Recovery Boiler Blog

WORLD RECORD RB - 6 ABLE " RUNNING " 365 DAYS ( 12 MONTH MORE )

noreply@blogger.com (Anonymous) — Sun, 24 Nov 2013 01:28:00 -0800

Recovery Boiler - 6 is one of the two boiler units operating in the RB - 1 ( RB - 5 and RB - 6 ) . Boiler is located in the area currently only Riau.And Recovery boiler - 6, listed as one of the boilers are capable of operated for 365 days , 12 months without any stop engine and trip since September 10, 2012 until now .

This success is a remarkable feat achieved by RB - 6 . It was supported by all parties, especially the DCS operator and operators in the field .
Just before RB - 6 can operate 8 months ( 253 days ) from the date of 6 September 2012 without any stop .

( Figure Profile RB - 6 )

Recovery boiler - 6, which is headed by Mr. Badot Krawang said that this achievement can not be separated from the contribution of all employees RB - 1 from head shift , team leader and all operators ( DCS & Field ) .
He added that the key to this success should be maintained as long as they can pay attention to the following aspects :

1 . Controlling replacement Shootblower
2 . Set the combustion air ( Primary , Secondary and Tertiary Water Flow )
3 . Charbed control in the furnace to avoid the Carry Over
4 . Conditions attention Spray gun ( Black Liquor System)
5 . Set the temperature Black Liquor

Then how can this be achieved , so that the RB - 6 Capable of operating for 1 year ?
Badot krawang confidently said , what is needed is :

1 . All employees must be generous and caring with which he worked
2 . Improve Team Work solid
3 . Good information between leaders and subordinates
4 . Improve Preventive maintenance performance
5 . Good in the air Controlling combustion ( combustion)
6 . Good operational maintenance
7 . Good in controlling Charbed

( Figure Team Work RB - 1 )

Any changes would have a new problem arises as a result of these changes , but not the issue that we fear but how we can confront and resolve the issue to our progress .

This achievement is not only the best se - APP group , but to the world level .

Hopefully this achievement can be a positive reference value for the existing recovery boiler in the APP Group in particular .

HOW TO OPERATION OF SILO TANK SALT CAKE

noreply@blogger.com (Anonymous) — Thu, 21 Nov 2013 17:47:00 -0800

A. Start-up preparation

1 . Make sure the tool Already Ready To Operated
2 . Make sure Manhole Bottom Already Closed Meeting
3 . Open Drain Steam Heating And Air Compressor
4 . Close Manual Valve Compressor Enters Into The Tank Na2SO4 Up Down
5 . Make sure Manhole Over Charging Sodium In Good Condition ( Can Open Close )
6 . Make sure Hoise Crane Can Operated

B. How to start up

1 . Open mp Steam Line Heaters
2 . Start Compressors What's In the Rb - 5 More With Less Pressure 5 Bar
3 . Open Air Floor Instruments What's In 2 Rb - 6
4 . Open manual Valve What's In Charge Tank ( Valve Venting )
5 . Open the On / Off Valve Air Wearing Instruments Manual
6 . Enter Sodium ( Na2SO4 ) 1 Ton Silo Into The Tank
7 . Close Manual Valve Venting And Close On / Off Valve Manually
8 . Close Compressor Tank Drain 75 % And Up Close Drain Line Compressor 0 %
9 . Open Manual Bottom Valve Compressor Enters Into The Tank Sodium
10 . If Pressure Valve Closed Back It Up
11 . Go to Top of Manual Valve Compressor More Less 40 % Pressure Will Hold Up 1-4 Bar
12 . If the pressure Ditangki It 0 % So Sodium In Tank It Out

C. How to Stop

1 . To do Flushing Line and Tank are incompressible
2 . If It's Really Clean stop compressor
3 . Open Drain Tank and Drain Line
4 . Stop the heating steam .

SALT CAKE CHARGING SILO TANK SYSTEM DIRECTLY TO PRIMARY AIR PORT

noreply@blogger.com (Anonymous) — Sun, 1 Sep 2013 08:55:00 -0700

Figure.Primary Air Port

Figure.Na2SO4 (Salt Cake)

Create a new innovation is a priceless achievement.
The company has a large plant requires a lot of creative people to improve the performance of a plant.Dan companies will benefit more as well as with employees who there.They-those involved in the project got the reward they deserve.

One plant that is able to demonstrate achievement in the Recovery Boiler

Recovery boiler plant has made a creative idea to create a system of consumption of salt cake (Na2SO4) had the salt cake filling directly on point to the Primary Air Port (PAP) for direct combustion in the furnace. Salt cake is in the contents of the silo and the salt cake are encouraged to use the air in the direction of the Primary Air Port (PAP).

By charging Na2SO4 using this new system then charging Salt cake (Na2SO4) became more abundant, whereas previously the consumption of salt cake in Recovery boiler is only 45 tons / day and after using the silo Salt cake consumption grew 15 tons of salt cake and the current total consumption of salt cake for Recovery boiler-1 can reach 60 tons / day.

With the addition of salt consumption in the cake Recovery boiler is the quality GL to RC sent in for the better, and sulfidity in RC could rise.

Hopefully this article can be useful for all people.

RECOVERY BOILER

noreply@blogger.com (Anonymous) — Mon, 20 May 2013 07:58:00 -0700

Figure 3.1 The position of recovery boilers in pulp mills

After a while the vacuum in to write about the recovery boiler because of the many activities, this time the author presents articles about the recovery boiler and the supporters.this time the author will present an article about the recovery boiler.

Recovery boiler boiler is a special unit used for obtaining soda or to purify inorganic chemical compounds (chemical recovery) contained in the black liquor from the digester and the rest of the cooking as well as generating high-pressure steam (high pressure steam).

Combustion occurs in the recovery boiler produced steam (high pressure steam) which is used as turbines and organic compounds melt like lava called smelt, smelt is then mixed with a weak white liquor (WWL) to green liquor (GL), to be transferred to recausticizing (RC). Recausticizing (RC) aims to process green liquor (GL) to white liquor (WL), which will be reused as an ingredient in cooking wood digester (Pulp making section).

Figure 3.2 Cycle of Chemical Process of HBL (Heavy Black Liquor)

The fuel used in the recovery boiler in the form of heavy black liquor (HBL). Levels of black liquor ranged between 15% -18% solid and should be concentrated prior to reaching solid levels above 62% to be burned in the recovery boiler furnace. Therefore the weak black liquor (WBL) was concentrated in a vacuum evaporator plant into heavy black liquor with a solid content of 70% -72%.

Heavy black liquor (HBL) contains 20-30% inorganic chemical compound with the main content of sodium carbonate (Na2CO3) and sodium sulphate (Na2SO4) and 40-50% of organic compounds derived from wood for cooking in the digester and the rest is water.

With heavy burning black liquor (HBL), heat energy is released around 3100-3500 kcal / kg dry solid. Furthermore, the thermal energy will partly be used to convert inorganic compounds and partly used to generate steam.

Heavy black liquor (HBL) with a solid content of between 60-70% is sent to the evaporator plant into the mixing tank. In the mixing tank, black liquor (BL) mixed with soda, ash from the hopper and ash coming from the electrostatic precipitator coupled with makeup salt cake (Na2SO4).

From the mixing tank mix of heavy black liquor (HBL), ash and salt cake was pumped through the spray gun to be sprayed into the furnace and dried by blowing hot air, and then clump together to form charbed bottom of the furnace and burned after reaching the point of combustion. The need for combustion air is blown through the primary, secondary, and tertiary windbox located around the bottom of the furnace wall.

Before arriving in the furnace, a process of drying, phyrolisis and gasivikasi by blowing hot air by the reaction:

CO + O2 CO2

H2 + O2 H2O

The division of air is set as follows:

- Primary air flow = 30-35% of the total air requirements

- Secondary water flow = 50-60% of the total air requirements

- Tertiary air flow = 10-15% of the total air requirements

Figure 3.3 Distribution of the combustion air in the furnace

To initiate combustion in the furnace and used to stabilize the combustion of diesel fuel is sprayed burner start-up and load into the furnace burner.

During combustion, the following process takes place in the furnace, namely:

1. Organic compounds burn off heat and partially turned into gas

2. Sodium sulphate (Na2SO4) is reduced to a compound of sodium sulphite (na2 ¬ S)

3. Organic compounds melt like lava called smelt

Na2SO4 reduction depends on the reaction between Na2SO4 direct contact with hot carbon compound (which results from the burning of organic compounds) at a pressure below atmospheric pressure, such as the following reaction:

Na2SO4 Na2S + 2CO2

Na2SO4 Na2S + 4CO2

Speed reduction can be calculated using the equation:

Speed Reducers = x 100%

If the conditions of combustion is complete, the speed reduction will reach above 95%. Inorganic compounds melt (smelt) will gather around the side charbed and flow out through the smelt dissolving tank into the spout. The result is called green liquor dissolving and sent to recausticizing section for further processing into white liquor which is then sent to the digester and reused as cooking ingredients (cooking liquor).

The rest of the air and combustion gases called flue gas still contains a high heat value. Flue gas is sucked / drawn by induce Draft Fan (IDF) in which the flue gas will pass through the boiler tubes that turned into a high-pressure steam (high pressure steam) which is then used to drive turbine generators for generating electrical energy. So the production side of the recovery boiler is a high-pressure steam (60 bar).

Reactions that occur during the furnace can be seen in the following figure.

Figure 3.4 Chemical Reactions Happens When Using Combustion Furnace Underway

While the physical events that occur can be seen in Figure 3.5.

Figure 3.5 Physical Events Occurring On When Burning Furnace Progress in

3.1 Feed Water, deaerator, and Steam Drum

Feed water (boiler feed water) is a mixture of steam condensate and makeup water demineralizer mixed in the reservoir tank. Feed water is pumped to the deaerator where the feed water is sprayed over the top of the deaerator were greeted with a blast of steam from the bottom of the feed water to heat up to a temperature of about 1300C and simultaneously releasing free oxygen seyawa of feed water.

Furthermore, feed water flows through three layers of perforated plate into steam scrubbing vessel and over flow into the deaerator tank. Some steam together with oxygen-free exit through the venting deaerator. Warming events and the release of oxygen in the deaerator steam depending on usage and settings deaerator pressure and level. To enhance the removal of free oxygen that is still attached to the feed water, chemical compounds injected into the deaerator Hydrazine (N2H4) is that the current or the Deha (heptyl diethyl adipate).

From the deaerator, feed water is pumped into the boiler by using a feed water pump. Feed water pump consists of 3 units (50 Hz) and 1 unit (60 Hz) are smaller capacity. In normal operation the unit used feed water 1 (50 Hz), and other water feed stand by.

Feed water from the deaerator is pumped into the bottom header economizer I through pipes with outside diameter 159 mm. From the economizer header I water moves upward toward the economizer header I through 67 line pipe economizer. From the upper economizer header I move down to the water below the header economizer II, from there the water upward through pipe line 67 II to economizer header above. Feed water is heated to temperatures up to 2300C and 1300C will flow to the steam drum through 6 Conductor pipe plumbing expenses.

There are 6 pipe down comer overall, two down comer pipe connected to the boiling tube header panel or generation bank as a liaison water from the steam drum to the generation bank. Mixture of water and steam generation for banks will flow to the steam drum and water in the steam drum boiler liquid phase and vapor phase are separated by a cyclone separator, where the vapor that forms collected in the steam drum level is called saturated steam and boiler water level below steam drum re-circulated.

Due to release of steam is formed, the levels of minerals in the steam drum more and more viscous. So to stabilize the mineral content of a small amount of water in the boiler steam drum disposed towards continual continuous blow down expantion tank. In the continual blow down expantion tank boiler water turns into steam and partly flowed into deaerator, while the rest are discarded to blow down tank.

To maintain the quality of boiler water, injected a chemical compound sodium hydroxide (NaOH) and sodium Posphate (Na3PO4) diperpipaan feed water into economizer I.

3.2 superheater and Main Steam

Saturated vapor collected in steam drum is called saturated steam, passed through the screen towards the superheater tube I, II, III. This area is heated vapor from saturated steam conditions up steam superheater.

Penginjeksian feed water area located between the superheater header superheater I II and III superheater. In normal operating conditions, the temperature steam superheater region can be controlled as follows:

- Temperature steam after superheater I = 3430C

- Temperature steam after superheater II = 3870C

- Temperature steam after superheater III = 4550C

3.3 Burning Black Liquor (black liquor firing)

The main fuel recovery boiler is heavy black liquor concentration results in the evaporator plant WBL. Heavy black liquor is pumped to the mixing tank and mixed with ash (dust) and saltcake makeup (Na2SO4 powder) and stirred with an agitator. Heated with steam to the low temperature of about 105-1150C to obtain a perfect mix and does not clot. HBL then pumped to the pipeline system into spray gun and heated again with the steam press medium in direct contact (direct steam heater) to reach the appropriate temperature, around 115-1200C.

HBL then sprayed into the furnace through 6 sets of spray gun are placed symmetrically on the wall of the furnace between the level of secondary and tertiary water ring water ring with 3 sets are 3 sets on the left and on the right is a wall furnace.

The factors that affect the combustion HBL is:

-% Of total solid

- Viscosity

- Temperature

- Angle spraying

- The type and size of nozzle spray gun spray gun

HBL viscosity depends on% total solids and temperature HBL. When high viscosity will cause the spray HBL too rough so difficult to burn in the furnace, and vice versa if low viscosity will result in HBL too fine spray and increase the occurrence and chemical loss carry over (TRS)

HBL Flow spraying spraying depends on pressure, nozzle size and number of spray gun is used. Charbed formation at the base of the furnace depends on the viscosity, flow HBL spraying, spraying angle, the type of spray gun and the amount of air delivery and pressure.

In addition, for memualai combustion in the furnace, to shut down and to stabilize the operating conditions, use start up and load burner. Start up the burner and burner load should always be treated and prepared for any time will be used. Diesel oil or diesel used as fuel penyanggga recovery boiler. The raw materials sector in the tank without solar accommodated isolated and without heated by the temperature of the surrounding air is hot enough.

The capacity of each oil burner is as follows:

- Start-up burner = 500 kg / h solar

- Load burner = 2000 kg / h solar

3.4 Combustion Air and Flue Gas

Air exhaled by the primary combustion air into the primary air ring fan, secondary air fan into secondary and tertiary water ring water ring fan towards tertiary water. Primary and secondary air is heated first steam water heater using low and medium pressure steam to a temperature of about 1500C before being distributed kesetiap water ring equipped with windbox damper-damper to regulate air pressure and equitable distribution.

The tertiary air tertiary didistribusikian to ring without heated water, this is to prevent the gas temperature is not too high superheater region so as to avoid the occurrence of excessive heat (over heating) in the superheater tubes. In normal operation with full load of fuel usage of the air in total around 160,000 Nm3 / h.

3.5 Electrostatic Precipitator and Induced Draught Fans

Flue gas from the furnace is inhaled using Induced Draught Fan where the flue gas will pass through the screen first and then pass superheater tube, boiling tube panel (generation banks), economizer II, economizer I go into Electrostatic Precipitator and drawn by Induced Draught Fan then exhaled out through the chimney (stack).

As we know, a large number of chemical dust (dust) will carry over from the boiler and when discharged directly into the atmosphere means a chemical (chemical dust) and lead to harmful air pollution. To solve this problem, the flue gas is passed through a function captures Electrostatic Precipitator ash (dust) from the flue gas and recycled into the mixing tank where dust is mixed with HBL and burned back in the furnace. Electrostatic Precipitator consists of two units, each consisting of three electric fields (fields) with their efficiency masi8ng 99%.

3.6 Soot Blower

Soot blower has a double function, namely to soot blowing in normal operation and for soot blowing water in washing water when shut down. The goal is the same, namely to remove the dust attached / collected on superheater heating surface area, generation bank, economizer economizer I and II.

3.7 Green Liquor

Green liquor is a major product of the recovery boiler. In the process, black liquor (BL) contains two types of compounds are organic compounds (lignin and wood fiber) and inorganic compounds (Na2CO3 and Na2S). So the organic compounds in the BL will burn to the gas, while inorganic compounds burn to melt compound called smelt. Melt chemicals (smelt) will gather around the charbed and flows out through a gap called the smelt spout toward the dissolving tank. In the dissolving tank. In the dissolving tank, the smelt will be dissolved with weak white liquor (WWL) of the RC section (Section Recaustizing) becomes green liquor (GL). After that, smelt GCC's late (green liquor) will be sent back to the RC for processing into white liquor through recaustizing reaction. White liquor is used as a cooking ingredient in the digester timber (pulp making section).

Figure 3.6 Storage Tank Green Liquor

3.8 Drain and venting

Drain operated to reduce or to empty the boiler water if needed. While venting operated to remove air bubbles or steam from within the system at start up. At shut down venting opened to release the remaining pressure from the boiler. Some of the drain is connected to the inlet header blow down before being discharged into the ditch.

3.9 Security System

Recovery boiler is also equipped with safety systems and auxiliary units, such as:

- Interlock System

This system serves to prevent damage in case of deviation boiler operating conditions.

- Safety valve

This tool serves to keep the boiler pressure does not exceed the limits specified security.

- System rappid drain

This system serves to empty the boiler water to a minimum, if there is a severe leak that caused water boiler piping into the furnace.

The system is operated at the time of emergency and went so fast that boiler avoid further damage.

3.10 Blow Down Tank Continious

Water quality is maintained by opening continious boiler blow down tank. The goal of getting rid of the water from the steam drum to keep the concentration of water and to help control the level of steam drum. Continious blow down open continuously so that impurities in the steam drum is lost.

3.11 Sample Boiler Water

For quality control of boiler water used five sampling lines through attemperatur. Boiler water samples attemperatur cooled using cooling water is indirect contact.

The source sampling are:

a. Demineralized water

b. Feed water

c. Boiler water

d. Saturated steam

e. Superheated steam

f. Deaerator water in

see also previous article"Operation of vacuum evaporator"

Maybe useful.

3.12 Personal Protective Equipment (PPE)

Personal protective equipment used in the recovery boiler is as follows:

Figure 3.7 Personal Protective Equipment (PPE)

WHAT IS THE ELECTROSTATIC PRECIPITATOR

noreply@blogger.com (Anonymous) — Fri, 17 May 2013 03:21:00 -0700

This article will discuss the application of electrostatic theories that have been discussed in previous articles here. Application of electrostatic in the industrial world are used to address the problem of waste dust. Among other industries that apply the power plant, sugar mills and cement plants, one way is to use electrostatic precipitator (ESP).
Electrostatic precipitator (ESP) is one alternative dust catcher with high efficiency (up to above 90%) and the range is quite large particles are obtained. By using electro static precipitator (ESP), the amount of waste dust out of the chimney is expected to only about 0.16% (effective capture of dust reaches 99.84%).

One of the most important component in the production process at the Sugar Factory and power plant is the boiler. Its function is as a place to heat water, thus producing steam that will be used for further processing. At the power plant, steam is used to rotate the steam turbine as the driving generator.Untuk do its work, the boiler requires the presence of heat used to heat water. This heat is supplied from a section called the combustion chamber or furnace, where the combustion chamber is equipped with a combustion appliance or burner. The results of combustion in the combustion chamber contains a lot of dust since the fuel used is coal, and the dust will be carried with the flue gases to the chimney. Before the flue gas exit through the chimney, the flue gas will pass through the grille of a electrostatic precipitator (ESP).

Figure 1. Electrostatic precipitator overview.

Figure 2. Percentage capture of dust particles in the ESP.

How it Works Electrostatic Precipitator

The workings of the electro static precipitator (ESP) are (1) passing the exhaust gas (flue gas) through an electric field formed between the discharge electrode to the collector plate, flue gas containing dust grains initially neutral and charged at the time of passing an electric field, dust particles will be ionized so that the dust particles become negatively charged (-). (2) The dust particles are now negatively charged (-) is then attached to the plate-plate collector (collector plate), see figure 4. Dust collected in the collector plate is periodically transferred back from the collector through a vibration plate (rapping). The dust is then dropped into the tank (ash hoppers), see figure 1 and 2, and transported (moved) into the flyash silo with the way in vacuum or exhaled.

Figure 3. The parts of the electrostatic precipitator.

Figure 4. The ionization process.

Electric Field Formation Process

The process of forming an electric field: (1) There are two types of electrode, which is negatively charged discharge electrode and the collector plate is positively charged electrode. (2) Discharge electrode placed between the collector plate at a certain distance (a distance between the discharge electrode with the collector plate). (3) Discharge electrode was given an electric direct current (DC) with a minus charge (see figure 3), at a voltage level between 55-75 KvDC (initial power source is 380 volts AC, then increased by a transformer to around 55-75 Kv and revamped into DC power by rectifiers, taken only potential negative only). (4) grounded collector plate (on-grounding) to be positively charged. (5) Thus, at the time of discharge electrode DC current then given electric field is formed on the chamber containing the electrode curtains and dust particles will be attracted to these plates, clean gas then moves into the chimney.

Electrostatic precipitator is one way to Steam Power (power plant) or other industries that could potentially generate dust waste into environmentally friendly, at least to reduce the pollutant content of the discharged through the chimney.

see also previous article "Mechanisms of steam soot blower erosion"

May be useful.

VACUUM EVAPORATOR

noreply@blogger.com (Anonymous) — Fri, 10 May 2013 16:04:00 -0700

3.1 Definition of Vacuum Evaporator

Vacuum Evaporator unit is a process aimed at concentrating the waste in the leaching pulp Pulp Making (Black Liquor) by evaporation of water from the Black Liquor using steam. Black Liquor with a high content of total solid fuel will be used in the Recovery Boiler.

Figure 3.1 Position in Vacuum Evaporator Pulp Factory

3.2 Principle of Evaporator

Production processes in the pulp and paper cycle is a very complicated process and each one of the unit processes depend on each other. To maintain the lowest possible production costs, many of the remnants of a by-product production (by Product) be recovered, for example: Weak Black Liquor is a by-product of wood in the digester at cooking pekatkan the evaporator and the fuel in the Recovery Boiler for the purification of chemical compounds and also the utilization of the combustion heat.

Pulp produced by cooking wood chips (Wood Chip) mixed with a solution cook (Cooking Liquor) in the digester. At the time of cooking, cooking solutions containing inorganic chemical compounds with the main composition of caustic soda (NaOH) and sodium sulphide (Na2S) reacts with the sap wood (lignin) so that the wood fibers (fiber) apart and break down into fine fibers. The sap wood is mixed with a chemical compound is separated from the fine fibers (fibers) and the solution. Cooking the remaining aqueous solution is called "Weak Black Liquor" (WBL).

WBL water contains approximately 85-90% and the remaining 10-15% is a mixture of residual chemicals and organic compounds cooking wood (lignin). Percentage of cooking chemicals and chemical compounds other than water is expressed as "Black Liquor Solid" (% TS).

To allow the purification of this chemical compound return, WBL was concentrated by evaporating most of the water content in the evaporator, to obtain a solution with a greater percentage of their chemical compounds of water content, about 70% TS. Concentrated solution is called "Heavy Black Liquor" (HBL).

HBL is easily burned in recovery boilers, where the organic chemical compounds (lignin) went up in flames and heat release, and inorganic compounds are converted back into shape first compound was then used again as a solution cook.

3.2.1 Evaporation (Evaporation)

The water molecule consists of two hydrogen atoms (ions +) and one oxygen atom (ion -). These ions are strongly bonded to each other and join together with other water molecules. Evaporation happens when water molecules on the surface of the solution receive sufficient heat to escape from the bonds of other water molecules and change the liquid phase to gas phase.

In other words, the primary function of the evaporator is to separate the water from the Black Liquor by evaporation. Basically, the black liquor evaporator is heated until it reaches the boiling point (boiling point) so that the water contained in the Black Liquor will gradually evaporate and turn into steam (vapor) and separated from the Black Liquor is the higher viscosity.

3.2.2 Boiling Point (Boiling Point)

Water in the sea level (P = 1 atm) will boil at a temperature of 100oC. At the boiling point, the water will gradually evaporate. But if the air pressure is increased up to 4.2 bar, the water will evaporate at a temperature of 153oC. Accordingly, the vacuum pressure of water at 0:16 bar (-635 mbar) only requires the boiling point temperature of 56oC. It can be concluded that the water pressure is proportional to the temperature of boiling water, when the pressure off the boiling point of water will drop.

Figure 3.3 The water pressure is proportional to the temperature of the boiling point of water

3.2.3 Boiling Point Rise (BPR)

The boiling point of pure water at varying pressures are shown in the steam table. But to a solution of water containing dissolved solids, the boiling point will be higher due to more strongly bound water molecules with the solid, so it takes a stronger heat by evaporation of water.

Difference between the temperature of the solution to the boiling point temperature of water vapor that is formed (pure water base) is called the boiling point or boiling point elevation rise. The greater the amount of dissolved solids or total solid percentage, the more heat required to raise the temperature in line with the increase of boiling point.

Figure 3.4 Effect of increase in the percentage of total solid of the BPR

Figure 3.5 Comparison of temperature with the temperature Liquor steam / vapor

Figure 3.6 Design Solid (%) and the Boiling Point Rise (BPR) in each effect

3.2.4 Economy

Economic terms or steam economy is used to calculate the amount of water evaporated per ton of steam heating.

We know that by lowering the pressure will cause a decline in liquor boiling point. In this way allows the water vapor produced in a unit can be used as a heater next to the unit throughout the pressure on the next unit is lower than the previous unit.

This principle is applied in a vacuum evaporator with the system and is equipped with a condenser, to allow the Black Liquor gradual release of water vapor by utilizing only water vapor generated in a heating effect as the other effect. With this may be noted that the evaporator system which consists of 6 effect steam economy has a higher than 3 effect.

3.3 Type Evaporator

a. Film Evaporator, divided into two systems:

- Rising Film

- Falling Film

b. Forced Circulation Evaporator

Forced Circulation Evaporator drain operated with a Black Liquor filled piping where evaporation does not occur in the piping, but in a separate room.

- Rising Film Type

A common type of evaporator is of type Long Tube Vertical (LTV). Where Black Liqour evaporate in the heat of condensed steam piping and piping on the outside (shell side) and Black Liqour turbulent flow in wetting the surface of the pipe.

Black Liqour inserted at the bottom of the piping and flows up through the pipeline once. Black liquor received during passage through the piping hot, out on the top of the piping and vapor release. Black Liqour overflow into effect with the higher temperature and the resulting vapor is passed as a heater in a cooler effect.

This type is less profitable, which in the event of interference with the black liquor flow rate will affect all other units and cause unstable operating conditions.

In other words, turn down rate is low, so the reduction in black liquor under the design flow is not possible because it will reduce the thickness of the layer of Black Liquor on the surface of the pipe and out of control, which in the end of evaporation process must be stopped.

- Type of Falling Film

Preheat the operation principle of Falling Film (PF) is similar to the principle of Rising Film where PF is the development and refinement of the Rising film with some striking changes.

PF is still using the type of LTV, which occurs in the vapor piping and liquor sprayed each coat the walls of the piping and the flow of black liquor layer is much faster.

Tables. 3.1 The main difference PF and Rising Film

Figure 3.7 Differences Rising Falling Film with Film

With this circulation system, the flow velocity layer of Black Liqour expected to be higher, wherein the residence time (residence time) Black Liqour in the pipeline would be shorter and the thickness of the coating on the piping Black Liqour is controlled by regulating the circulation flow rate. The advantage is the tendency of scale formation is reduced and can be operated at turn down a lower rate, where the evaporator can operate normally with a low capacity of approximately 25% of the design.

To keep the load flow to Black Liqour Liqour Black coating thickness on the pipe steady and evenly, Black Liqour vapor is circulated from the body back into the distribution box at the top of the piping. Therefore, the operation of the circulation pump plays an important role of the evaporation system, where there is no other possibility to maintain the operating condition when the circulation pump can not run / damaged.

Black Liqour circulated through the piping at the top of the discharge pipe is placed at the center of the pipe heater (heating element) is called a preheat section (preliminary heating section). In this section Black Liqour temperature rose slightly and will release a little steam after arriving at the top of the liquor box. Then through a distribution box, Black liquor is distributed evenly kesetiap heating piping.

Steam or vapor is passed through the heater header and distributed around the outer wall heater through the piping and piping condensate after releasing heat.

Distribution of vapor and condensate separation as well as NCG gas collection takes place with the help of horizontal baffles arranged in such a way in the shell side.

Baffle also serves as a barrier (support) piping on body equipped with a vapor of Regional euroform entrainment separator, which serves to filter the vapor before it flows into the next effect, where if there is black liquor carry-over will be captured in the separator.

Separator consists of the elements in the form of a series of parallel baffles, where the incoming vapor direction vertically then deflected three times before exiting the separator. In this way the Black Liquor is shipped will be attached to the baffle separator, clump together and unite to form larger droplets, and falls by gravity back to the solution of Black Liquor.

Figure 3.8 Cross-section Evaporator

Figure 3.9 Cross-section Evaporator Body

Figure 3.10 Principle of Evaporator

Figure 3.11 Increase in Total Solid in every effect

Figure 3.12 The difference in temperature of heating steam temperature Black Liquor

3.4 Heat Transfer

Basic equation for Heat Transfer (Heat Tansfer) is:

where:

Q = Total heat energy is required (Kcal / h)

U = Heat Transfer Coefficient (Kcal / h.m ². º C)

A = Area of heat transfer area (m2)

 T = temperature difference between steam and vapor heating temperature Black Liquor premises (oC)

Matters affecting the Heat Transfer:

A. Scaling on the tube

2. Low Temperature Black Liquor

3. High levels of chemical in Black Liquor

4. High solid Black Liquor

5. The low velocity in a tube of Black Liquor

6. High viscosity Black Liquor

3.5 Description of Process Weak Black Liquor to Heavy Black Liquor

Weak Black Liquor at a concentration of 15% is pumped into the Feed Tank Flash causing the temperature of the vapor into the PF-6 and then go to PF-5. Of PF-5 PF-4 entered, then the PF-3 and then to the PF-2. Liquor from PF-2 body vapor through the reflux condenser to the PF-1 (A, B, C, D). In every body is equipped with circulating pumps and transfer pumps in effect 6,5,4,3 and 2. In every effect is also equipped with a control valve that regulates the amount of liquor in the transfer. On a three-body effect in operation and a standby body (washing / washing). Only one pump that serves as a transfer and circulation, unlike the other effect. Of the fourth body in effect one connected with each other piping with a program sequence. Piping system is equipped with an automatic on-off valve.see also previous article
"What is the recovery boiler?"
Maybe usefull.

BURNER MANAGEMENT SYSTEM (BMS)

noreply@blogger.com (Anonymous) — Wed, 8 May 2013 07:35:00 -0700

Technical data

Capacity oil 500 kg/h
Oil pressure ~ 6 bar
Combustion air pressure ~ 1200 pa
Atomizing steam pressure ~ 10 bar
Capacity, ignitor 125 kw
Gas pressure ignitor inlet ~ 0.1 bar
Air pressure ignitor inlet 1.0 kpa

Burner assembly

1. View for right side

2. Front view

3. Port view

4. Damper

5. Front part with oil gun and ignitor

6. Oil gun nozzle

I. Instructions

1. Preparation before operation

Fulfil before interlocks
Open the oil header valves to start circulation of oil to the burners
“burners permitted” should be indicated
Fulfil interlockings for boiler purge unless “liquor fire” or “burner in operation” is indicated
Open gas header valves
“permission to start” should be indicated

2. Start of burner

Make a insfection of burner opening into the furnace and clean it if necessary
Mount a well cleaned oil gun into the burner and connect hoses for for oil and atomizing medium
Insert burner into operation position
Open manual valves for oil, steam and ignitor gas
Adjust combustion air pressure to ~500 pa
“burner ready to start” should now be indicated
Press “start” push button
When “burner in operation” is indicated, adjust the combustion air to ~1200 pa and set the amount of rotary or parallel air
Rod the burner port frequently operation

3. Scavenge and stop of burner

Check if gas header valves is open
Check local manual gas valve is open
Press push button “stop & scavenge in progress” is not indicated any longer
Refract the burner to retracted position
Close manual valves for oil, steam and ignitor gas
Disconnect hoses for oil and atomizing steam
Adjust the combustion air pressure to ~250 pa. This will maintain enough cooling of the burner and winbox
Dismount the oil gun and clean the nozzle according to recommendations

4. Separate scavenge of burner gun

A separate scavenge is done when a burner tripped or if the operator like to do a extra scavenge to clean the oil gun better.

Check if gas header valves is open
Check if local manual gas valve is open
Push the burner into inserted position
Press push button “stop & scavenge
Wait for ~30 seconds until ” scavenge in progress” is not indicated any longer
Retract the burner to retracted position
Close manual valves for oil, steam and ignitor gas
Disconnect hoses for oil and atomizing steam
Adjust the combustion air pressure to ~250 pa. This will maintain enough cooling of the burner and winbox
Dismount the oil gun and clean the nozzle according to recommendations.

4. Burner tripped

Check first out information
Make changes according to first out information if possible.
Wait until boiler purge or reignition delay time is done try to start the burner again or make a separate scavenge of the oil gun.

II. Maintenance instruction

1.Cleaning of the oil gun nozzle

Replace the lock nut.try to avoid drop the top part of the nozzle.
Take out the nozzle top part

a. Clean holes in the nozzle with a suitable tool.

b. Clean the gap with a thin piece of metal.

Check if all opening in the nozzle base part is clean and that both copper gaskets are ok.
Check the status upon the locknut threads and threads on top of the oil gun.
Assemble the nozzle top part and locknut with the oil gun

Note: don’t use exesive force due to problem during disassemble when the oil gun is hot

Put the oil gun to storage or back into the burner.

Start oil burner and burner management system

1. Oil burning equipment, in general

The boiler is equipped with 3 straight burners whose function are:

Heat the boiler and create conditions for a safte liquor light-off, increase steam, -pressure before start of the liquor firing.
Support the liquor-firing when necessary
Enable a fast burn down of the smelt bed
Produce steam

The start burners are oil fired and are located in the secondary air register. They are equipped with individual air registers and air dampers. The oil is atomized by pressure steam (10 bar). The combustion air is supplied by the secondary air fan.

The burners are semi automatic. Manual insertion of oil burner gun and ignitor is needed before start up. When the gun is mounted and put into operation position the BMS will run the start up sequence upon order from operator.

Each burner is equipped with a gas-electrical igniter. An air fan supplies the igniters with combustion air and the flame scanner with cooling air. The cooling of the flame scanner must not be shut off more than for very short periods of time when the boiler is hot.

2. Oil System

The oil system consists of the following main components

One manual valve to isolate the start burner oil system
Automati main shut off valve. The valve is interlocked with the burner management system and automaticly shut off when the following occurs, emergency stop, emergency shut-down procedure, “fail to close” error on an individual safety shut-off valve.
Flow measurement
Flow controller for measuring of the oil flow to the burners. The oil flow is calculated as the difference between this oil flow and the oil flow in the oil return pipe.
Pressure control valve to reduce and maintain a oil pressure ~8 bar.
High pressure gauge, which interlocks the burners when the oil pressure gets to high (overload).
Low pressure gauge, which interlocks the burners when the oil pressure gets to low (to avoid operation during problematic conditions)
The following main components are located between the main oil circuit and the individual burners:
Manual shut off valve for oil. Close this valve before removal of oil burner gun.
Double automatic shut off valves that close when interlocks are activated. If these valves are not “provent” closed when they are supposed to, the error “failure to close” occurs and the main oil shut off valves close automatically.
Automatic valve that opens between the oil to the burner and the atomized steam for cleaning of the oil burner gun and hoses.
Pressure gauge for indication of oil pressure in oil burner gun.
The following components are located in the oil return pipe:
Low pressure gauge for oil. A warning is issued at to low temperature.
Flow measurement
The recirculation valve is interlocked the same way as the main oil shut off valve (see above).
Check valve which prevents oil to reach the burners from the oil return pipe.
Manual valve which can isolate the oil pipe around the boiler from oil flow.

3. Atomizing system

The oil is atomized by medium pressure steam (10 bar)

The atomizing system consists of the following components:

Each burner is equipped with the following components:

Manual valve and check valve. Close the manual valve for removal of the oil burner gun.
Always remove the atomizing hose first. Always connect it last.
Low pressure gauge that interlocks the operation of the burner when the pressure in atomizing steam gets to low.

4. Combustion air system

The combustion air is supplied from the secondary air fan och and the flow is regulated by the damper.

Each burner is equipped with:

Pressure gauge for the pressure of the combustion air fed to the burner.
Low pressure gauge for the air that interlocks the burners operation.

5. Ignition gas system

The ignition system supplies the gas-electric igniters with gas during start-up. It consists of the following components:

Self actuating valve that brings down the pressure from the bottles to 0.1 bar.
Two shut off valves and one ventilation valve in between. The valves controlled by the same signal. The valves are interlocked by the safety system.
Two pressure gauges: one high- and one low pressure gauge that interlocks the gas header at too high or low pressure.
Pressure gauge for indicationof gas pressure in igniters. The pressure should be 0.05 – 0.15 bar.
The gas header then leads to each and every burner and each burner is equipped with the following:
Manual valve that shall be shut off for maintenance or service of the igniters.
Automatic shut off valve, controlled by the burner safety system.

6. Ignition and cooling air system

The ignitors combustion air is supplied by the cooling air fan. The cooling air fan also supply purge and cooling air to flame scanner on each oil burner. The system consists of the following components:

Low pressure switch that interlocks start-up of igniter at to low air pressure. Burnes operation will not be affected by the low pressure switch, that it is interlocked against start-up and oil gun scavange.
Local pressure indicator. Pressure during operation of fan should be ~4 kPa.
The air header then divides with one pipe to each burners is equipped with:
Manual valve for turning on/off the air. Note that the valve should only be closed during maintenance and service because the igniter and flame scanner need cooling.
Regulator for adjustment of air pressure to igniter. Proper air pressure varies in different installations due to different conditions in different boilers. The pressure to the igniters is set at start-up of the burner system. A check of correct air pressure can be done by looking at the flame. The most common error is too much gas flow in relationto the air flow. Too much gas flow puts the flame out. To little air flow gives a yellow flame and too much air flow gives a pinkish blowtorch looking flame. Incorrect air /gas flow does not give flame indication from the igniter (igniter in operation).

7. Burner Design

7.1 Design

Start burner design described below:

Figure1. View from side

Figure2. View from front

Figure3. View of fort, swirler and nozzle

The burner is a oil fired burner with a separate air register of parallel air type. It’s nominal capacity is 500 kg/h oil.

The capacity of all burners can be adjust with the pressure control valve in oil header line. (500 kg/h should be reach at-6 bar).

Atomizing air are to be delivered to the burner at 10 bar.

Air register contains of one cylindrical drum with a front plate bolted on to the secondary air drum. The air register is mounted into the tube wall opening.

On the burner front plate there is openings for sight glasses and rodding ports. All burner are equipt with flame scanners to monitor the oil flame. This is also mounted on the front door.

The amount of combustion air can be adjust with inbuilt damper. The damper position can be adjust with the adjusting wheel palced into the front palte.

Caution! The combustion air to the burner is not to be closed totally to secure enough cooling to the burner and burner air register.

Within the burner air register there is also a damper adjusting the amount of parallel or rotary air. By positioning the cylindricaldrum with the rod implemented on the front plate, you will partly cover the rotary air or parallel air register. With the rod totally inserted you will have 100 % parallel air.

By changing the amount rotary or parallel air, you change the looks upon the oil flame. With rotary air you will have a shorter and wider flame. Depending on the conditions in the furnace close to the burner you’ll have changes on the looks of the oil flame and also changes in the signal quality from the flame scanner.

The oil gun consists of two concentric pipes, where the oil goes through the inner pipe and atomizing steam between the inner and outer pipe. The burner is connected to each medium pipe by flexible hoses with quick couplings. Each quick couplings have a inbuilt check valve to minimize leakage from the hoses when being disconnected from the burner.

Figure 3. Oil gun with front door, swirler and nozzle.

The oil gun is inserted in the swirler pipe. The swirler pipe is mounted upon the front door. The oil gun nozzle position in the tube wall opening can be adjusted changing the position of the clamp. A equal clamp can be found to adjust the swirler position in the tube wall opening. The swirler task is to create stabil conditions close to the oil gun nozzle.

The distributed to the furnace by a nozzle described above. Thrue the nozzle the oil will be atomized by midpressure steam and create a fine mist of oil. The type of nozzle is written on to the nozzle base.

Figure 4. Oil gun nozzle.

7.2. TECHNICAL DATA

Capacity , burner 500 kg/h

Oil Pressure ca 0,6 MPa

Combustion air pressure ca 800-1500 Pa

Atomizing steam pressure ca 1,0 MPa

Capacity, initor 8 kg/h

Gas pressure, ignitor ca 15 kPa

Combustion air ignitor ca 2 kPa

7.3. Maintenance And Service

In order to achive suitable combustion it is important to make sure the nozzle is not cloed up dirt or worn down.Cloin up of single holes in the nozzle can affect the combustion.

To remove of the nozzle, the nut should be removed first. (See Figure 4). In order not to damage the threads it is recommended that the oil burner gun is cooled of before dismantling. When the nut has been removed the top part of the nozzle can be removed. After that the nozzle base part can be dismantled from the gun.

Note that the surfaces between the top and base part of the nozzle have a sealing affect, therefore handle these gently.

Clean the nozzle and make sure the holes and clean from dirt. When assembling the nozzle, make sure the 2 two differentcopper gaskets for oil and steam are in place. Also make sure the threads outside and inside of the pipe are clean and lubed with heat resisting lube.

NOTE! Prior to assembling of the nut, there is a gap between the guns outer pipe and the nozzle. This is because the nut centers the nozzle and the uns inner pipe. The gap is tightened when the nut is assembled.

The nozzle position in relation to the swirler can be adjusted by a clamp rin mounted on the oil burner un. Recommended distans between the top of the nozzle and the front of the swirler is approximately 35 mm.

Swirler position in the burner opening has great affect of the burners flame stability. The support pipe of the gun and the swirler should be retracted as far as possible without the oil mist hitting the port opening. Swirler position in the burner can be adjusted by a clamp ring mounted on the swirler pipe.

When the burner is not in operation the swirler and gun is retracted in the air register and the cooling air from the secondary air fan is kept on. Recommended coolin air pressure is approximately 250 Pa.

THE STEAM TURBINE

noreply@blogger.com (Anonymous) — Tue, 23 Apr 2013 10:06:00 -0700

There are three (3) important things that should be known by an operator to operate the power plant or the Power House.

1. SAFETY:

a. Security for the people (person). In this case to avoid the things that can cause an accident.

b. Security for equipment (equipment) prevent damage to the equipment with respect to the implementation of the operation as recommended by manufacturer (Manual Book) as well as good maintenance.

2. RELIABILITY / reliability of the unit by way of maintaining continuity of operations.

Avoid the trip unit by mistake and shut down operations due to equipment malfunction. In this case of course, supported by good maintenance.

3. Effeciency:

Carry out operations in order to achieve a high EFF by following operating instructions as recommended by manufacturer.

Before we discuss further steam turbine, it is good we need to know:

2. Power House = use his own power plant →

↓

- Factory

- Offices

- Housing

- Schools

- Mosques and Churches

- etc

Steam Turbines: is a first mover that converts the steam into potential energy kinetic energy. Further kinetic energy converted into mechanical energy in the form of the turbine shaft rotation

 CLASSIFICATION OF STEAM TURBINE

Steam turbines can be classified into categories berbedatergantung in construction, heat reduction process, the conditions of the beginning and end as well as its use in industrial steam as follows:

1. According Total Pressure Level:

a. Turbine Atua one level with one more level of speed that is usually a small capacity. The turbine is mostly used to drive centrifugal compressors and similar machines.

Example: Turbine DE-LAVAL (Fig. 1)

b. Impulse turbine with a single pressure level and the level of velocity (speed) double (compound). The system is applied to a single rotor turbine with curtis. (Fig.2)

c. Impulse turbine with multiple pressure levels and the rate is applied to the system velocity Rateau turbine. (Figure 3)

d. Impulse turbine with multiple velocity levels of stiffness with this system applied to the dual rotor turbine Curtis (Figure.4)

e. Turbine system using a combination of Curtis-Rateau (Fig.5)

f. Reaction turbine with multiple levels and a level of velocity. The system is applied to the turbine Parson (Figure. 6)

g. Impulse turbine combination - reaction. This system is applied in combination Curtis-Parson (Figure.7)

h. Reaction turbine with a rotor and a double round. The system is applied to the turbine Ljungstrom (Fig. 8)

Figure 1. Turbine Impulse Pressure Level and Velocity Single

Figure 2. Turbine Impulse Pressure Levels With Velocity Single and Dual Rate (Compound)

Figure 3. Turbine Impulse Pressure Level One Double and Velocity

Figure 4. Turbine Impulse Pressure Level and A Level Dual Velocity

Figure 5. Turbine Combination

Figure 6. Reaction Turbine With Pressure Level Double and One Velocity level

Figure 7. The combination of impulse turbines - Reaction

Figure 8. Reaction Turbine With Rotor and Round Doubles

2. According to the Steam Flow Direction:

a. Axial turbine, the steam is flowing in a direction parallel to the axis of the turbine.

b. Radial turbine, the steam is flowing in a direction perpendicular to the axis of the turbine.

3. By Number of Cylinders:

a. Turbine Single Cylinder

b. Turbine Double Cylinder

c. Three turbines slinder

d. Turbine Four Cylinder

4. According Methode settings:

a. Turbine with strangulation settings (throttling) the fresh steam entering through one or more (depending on power generated) strangler valve operated simultaneously.

b. Turbine with a steam nozzle arrangement fresh go through two or more regulators opener (Opening regulators) are sequential.

c. Turbine with setting step (by-pass governing) that besides the fresh steam supplied to the first level also directly channeled to one, two or even three mid-level turbine.

5. According to Steam Action Principle:

a. Impulse Turbine, its potential energy converted to kinetic energy in the nozzle or the passage formed by the stationary blades (blade guide) adjacent and in the motion blades (blade movie) kinetic energy is converted into mechanical energy.

b. Reaction turbine steam expansion axial blade passes between both blade guides and blade motion. Each level takes place almost at the same rate.

c. Radial reaction turbine without blades steering silent.

d. Radial reaction turbine with blade guides that are silent.

6. According Process Heat reduction:

a. Condensing turbine (condensing turbine) to the regenerator, in this type of steam turbine at a pressure lower than atmospheric pressure is applied to the condenser, the vapor also dicerat addition of medium levels of filler kettle to heat water, the amount of penceratan usually 2 to 3 to 8 - 9.

Latent heat of exhaust steam condensation during the turbine's all gone.

b. Condensing turbine with one or two penceratan of the medium at pressure levels for industrial purposes and heating.

c. Pressure turbine opponents (Back Pressure Turbine) exhaust steam is used for heating and industrial purposes.

d. Overlap turbine, the turbine is also opposed to the type of turbine pressure difference that is still used for the exhaust steam turbines condensing medium and low pressure.

e. Pressure turbine opponents (Back Pressure Turbine) with penceratan steam from medium levels at a particular pressure, in order to supply steam to consumers at various pressure and temperature conditions.

f. Low pressure turbine (pressure Discard) exhaust steam from steam engines used for power generation purposes.

g. Pressure turbine mixed with two or three levels of pressure with exhaust steam supply to the medium levels.

7. According to Steam Conditions Log In Position:

a. Low pressure turbine (Low Pressure Turbine) pressure (1.2-2.0) atm.

b. Intermediate pressure turbine (Middle Pressure) pressure (2-40) atm.

c. High-pressure turbine, the vapor pressure (40-170) atm.

d. Very high pressure turbine, the steam pressure (170-225) atm.

e. Super critical pressure turbine, the vapor pressure exceeds 225 atm.

8. According pemekaiannya industry:

a. Stationary turbine with a constant rotational momentum is mainly used to drive the alternator.

b. Stationary steam turbine varies with the rapidity which is used to drive the blower, turbo, air dealers (Air Circulator), pumps etc..

c. Turbine is not stationary with varying rapidity, turbines of this type usually used steamers, ships, railroad locomotives (Locomotive turbo)

All types of turbines that have been described above are dependent on the rapidity turn can be connected directly or through a reduction gear with engine-driven machine.

 STEAM TURBINE in use

Many industries use steam for industrial purposes except for process heat, or mechanical energy is also power to run the plane. Because of the special nature of the heat release time, the heat exchanger to heat during the process handover to the medium to be heated. Mechanical power of steam addition can be useful if the process temperature and high vapor pressure, further expands in the turbine pressure allowed an opponent to the required pressure.

Turbine Industry Divided Over Five Group:

1. Pressure turbine opponents (Back Pressure Turbine)

2. Condensing turbine (Condensing Turbine)

3. Extraction turbine / drain (Extraction Turbines)

4. Turbine combination (Mixing Turbines)

5. Turbine waveguide.

ad.1. Pressure Turbine Opponent:

pressure turbine opponents used when an industry that requires multiple steam as a source of potential energy as well as energy sources for processing purposes.

Figure 1. Pressure Turbine Opponents

ad.2. Condensing Turbine:

Condensing turbine is used when all the energy is used to generate steam power, while the former steam condenser is condensed into the opponent under pressure low enough to produce a high power, condensate water can be recirculated into the kettle.

Figure 2. Condensing Turbine

Ad.3. Turbine extraction:

Extraction turbine is divided into two types:

1. Extraction condensing turbine

2. Pressure extraction turbine opponents

Extraction condensing turbine, operating with dual vapor evaporation, which is in addition to power generation, as well as to supply the necessary steam extraction purposes.

Figure 3. Kettles turbines - Pressure Fight

ad.4. Mixed turbines (Turbine Mixing):

Turbine mixture also known as mixed pressure turbine (Mixed Pressure Turbine).

Low or medium pressure steam is used processed blended into the next level of a condensing turbine or a turbine pressure to boost power turbine opponents.

Figure 4. Mixed Turbines

ad.5. Turbine Pandu:

The turbine is also called pressure turbine turbine opponents because it is associated one or more existing turbines, specifically planned for a low initial pressure.

Figure 5. Turbine Pandu

 STEAM TURBINE PARTS

Steam turbine consists of several main parts such as:

1. Turbine house (Casing)

2. Rotating part (rotor)

3. Blades

4. Cushion

ad.1. Turbine house (Casing)

A turbine casing houses that make up the room (chamber) around the rotor to allow steam to flow across the blades.

Pedestal that serves as a buffer to put the pads are attached to the rotor casing. Generally one pedestal tied (Anchored) kepondasi dead, while others are placed on rail launcher (Sliding Feet) so that the casing to move freely. Due to the effect of expansion and contraction (Contraction), usually pedestal foundation is tied to the low pressure side of the pedestal or side adjacent to the generator (Generator End), while the other side is left to be able to move freely. When the casing and rotor temperature rises, the entire turbine construction will expand.

By placing one above the pedestal rail launcher (Sliding Feet), all turbine parts can move freely as it expands and as illustrated in Fig.1.

Figure 1. At the foundation casing construction

 Configuration Casing:

1. Casing intact

The entire casing is an integral part. Generally applied to the construction of small turbines.

2. Separate casing (Split Casing)

Turbine casing is 2 separate parts horizontally and connected into one binder bolts.

The second part of the casing, respectively called the upper casing (Top Half) and the casing bottom (Bottom Half). This construction is more widely used because of demolition and installation is relatively easy.

 Design Casing:

Turbine casing distinguished 3 categories:

a. Single Casing

b. Double Casing

c. Tripple Casing

Almost all of today applying steam turbine casing design double or triple casing for the period startnya faster, smaller problems of differential expansion and maintenance is relatively easy.

ad.a. Single Casing

Generally applied to the design of the old turbines and small capacity. Nevertheless turbines currently still no single casing design that applies mainly to the turbines for propulsion boiler water pump filler (BFPT). When this design is applied to large turbines, the turbine casing will be very thick so it takes quite a long time in the period of "warming" when it start to reach the full expansion.

This is because the walls are very thick casing and only heated by steam from one side of the inner side. These conditions resulted in substantial temperatu difference between the inner surface of the outer casing to the surface.

Thus the time required for temperature equalization becomes longer. Illustration of single casing turbine can be seen in Fig.1. following.

Figure 1. Single Turbine Casing

When the temperature of incoming steam turbine 454 ° C, then when the start-up temperature of the inside of the casing is also approaching 454 ° C. While the outside of the casing temperature is outside air temperature or about 38 ° C.

Thus, at the start there is a difference in temperature between the inner surface of the outer surface at 416 ° C.

The inside tends to expand while the outer portion is relatively not going to expand.

When the temperature difference is large enough, then in extreme conditions can cause cracks in the casing is quite thick.

ad.b. Double Casing

In double casing design consists of 2 turbine casing for each cylinder. Thus, the thickness of each - each case is only half the thickness of a single casing. Thus the distribution of heat and expansion process becomes faster.

Besides, as each segment becomes lighter casing, then maintenance becomes easier or faster.

As an illustration for tirbin double casing can be seen in Figure 2 below.

Figure 2. Double Turbine Casing

When the temperature of 460 ° C steam turbine atmospheric temperature being 38 ° C the difference in steam temperature 422 ° C. Double casing design advantage is that the Δt at 422 ° C is divided in 2 incoming steam casing, the casing (inner casing) at 460 ° C and out at about 349 ° C and then flows to the outer casing (outer casing) which means heating side the outside of the inner casing.

Thus Δt inner surface and outer inner casing is:

460 ° C - 349 ° C = 111 ° C

Moderate temperatures and the inner surface of the outer outer casing is:

349 ° C - 38 ° C = 311 ° C

Thus, in each case Δt becomes smaller to reduce possible cracking.

ad.c. Tripple casing

In the design of the casing tripple each cylinder consists of 3 pieces of the inner casing casing, intermediate casing and outer casing.seperti shown in the figure below.

Each casing walls become thinner and the relative temperature difference (Δt) each case will be lower so the time for even heat distribution is relatively even shorter.

Figure 3. Tripple Turbine Casing

ad.2. Rotor

Turbine rotor consists of a shaft with rings formed from a series of heated blades are aligned along the axis.

The rotor is the part of the turbine that converts the energy contained in the steam into mechanical energy in the form of shaft rotation.

In general there are two types of turbine rotor:

- Type rotor disk (Disk)

- Rotor drum

- Rotor disk type

On this type of rotor disks (Disk) is mounted on the shaft to form a disc ranks as shown below

Figure 4. type disc rotor (disc)

- Rotor drum

This type of rotor, shaft casted and shaped as desired and direct a series of blades mounted on a shaft. Rotor drum is very versatile and can be worn almost all types of turbines.

As an illustration of this type of rotor can be seen in the picture below

Figure 5. rotor drum

ad.3. Blade

is part of a turbine blade wherein the energy conversion occurs on the blade itself consists of a blade root portion, the body blades and blade tip as shown below

Figure 6. turbine blades

Blade as shown in Figure 6, then strung together to form a full circle.

The existing series of blades that functioned as the blade path and there are functionalized be fixed blade.

Series of blades mounted around a street circuit rotor blades are fixed mounted around the inner casing. The series blade serves to kinetic road steam into mechanical energy in the form of turbine shaft rotation. Being fixed blade, in addition there is a function to convert heat energy into kinetic energy, but there is also a function to reverse the flow direction of steam. Examples of the blade series can be seen in the picture below

Figure 7. blade path

In figure 7 shows that the blade root section is drilled into the grooves around the rotor, while the ends of the blades are united by a plate bajapenghubung called Shroud.

Shroud serves to strengthen and reduce the vibration of a series of blades. Fixed blades are generally arranged in a semicircle on a segment called the diaphragm as terliahat in the picture below

Figure 8. Fixed blade

One segment of the diaphragm and then mounted on the casing around the bottom being a partner dippasang diaphragm segments at different parts of the upper casing.

When these two chassis together, between the diaphragm to form a full circle.

In general there are two types of blades:

- Blade impulse

- Blade reaction

Figure 9. impulse blade

On impulse blade, the entire heat energy changes into kinetic energy carried in fixed blade (nozzle).

When the blade across the road, the pressure did not change and theoretically, the vapor pressure before the blade the same way with the vapor pressure after the blade.

Because the turbine impulse pressure is often called flat. Denagn Thus, the turbine shaft with blades impulses arise virtually no axial force on the shaft.

Picture 10. blade reaction

Being on the blade reaction, some of the energy is converted into kinetic energy heat fixed and partly disudu disudu road.

Result: each blade through the ranks, the ranks of both fixed blade and the blade line, vapor pressure will decrease. Consequences on the turbine blades reactions, axial forces arise quite big on the rotor shaft.

ad.4. Cushion

as part of a rotating, the rotor has a tendency to move in both radial and axial direction, because it's riveted rotor should be good to avoid a shift of radial and axial overload. Diapkai component for this purpose is called bearing (Bearing).

Steam turbines are generally equipped by:

- Bearing journals (journal bearing)

- Axial bearing (thrust bearing)

to support the rotor and rotor to shift mebatasi. Picture below is an example of a typical bearing above.

Picture 11. Cushion

On journal bearings, the inner surface of which may be in direct contact with the surface of the metal shaft coated by white (white metal / Babbit) are soft. Besides, there is also a channel - the channel where the lubricating oil to flow into the channel Diman Bantala and lubricating oil can flow out left bearing.

While the axial bearing (thrust bearing) consists of a disc umumya (thrust collar) which is part of the shaft and the two shoes (thrust pad) attached to the casing. Axial bearing function:

- To control the axial position of the rotor relative to the casing.

- Prevents the interface between the rotating part with a stationary part.

Axial retaining Style

1. Dummy Piston / Piston Balancing

Directors at the turbine pressure drop occurs in each row of blades - blade motion, will mengakibatka onset enormous force on the rotor where the direction of the force is in line with the flow of steam.

So to reduce the load on the bearing axial (thrust) axial force is balanced with a counterweight or a dummy piston piston mounted on the turbine rotor.

Image. Piston construction balancer

On the turbine casing which has a cylinder with double or tripple dummy casing is connected to the piston-cylinder steam out, but on a machine - a machine that old low-pressure side of the dummy piston cylinder low pressure associated with.

To reduce steam leakage at the edge of the dummy piston seals fitted labyrint types.

On the high and low dummy mounted piston seals (seal labyrint). Difference in surface area between the low pressure side and high pressure side dummy piston gives rise to the pressure difference between the two sides of the dummy piston.

Differences so as to produce sufficient thrust to offset the effect of axial gay steam flow through the turbine blades.

If still no resultant force is usually small enough, then this style will be muted by Bantala axial (thrust bearing) mounted on the front turbine

Dummy piston is only required on turbine blade with single wing type of reaction.

On the type of impulse turbine no vapor pressure reduction in blade - blade motion.

To ensure this, it made a hole - the hole offsetting pressure on the rotor rim.

The turbine - turbine flow like the IP cylinder and low pressure cylinder (LP) arising force - axial force opposing directions.

Thus the force - axial forces will cancel each other out with each other.

2. Bearing Axial (Thrust bearing)

Axial bearing construction which is widely used in steam turbines:

- For the turbine shaft flexible coupling connected with each spindle has its own axial bearing.

- For turbines with solid coupling mounted only one axial bearing is usually placed between the cylinder the cylinder HP LP

Image. Location Thrust Bearing

BOILER PRINCIPLES

noreply@blogger.com (Anonymous) — Thu, 18 Apr 2013 01:20:00 -0700

Highlights

1. Definition boilers & steam forming process

2. Type boiler combustion system based

Furnace bed material
Excess / shortage of type-type boiler

3. System maintenance boiler

New Boiler / renovation
Routine care (internal)

4. Boiler interlocking

1. Boilers and process of formation of steam

Boiler (boiler) is a closed pressurized vessel,where water is converted into steam by the provision of heat (heat).
When the water is heated in a closed vessel (boiler) with
The addition of some heat, there will be a phase change from liquid to gas (evaporation process)
With increasing pressure, the boiling temperature of water will also rise.
vapor formed during the process of boiling at a certain pressure is still a steam / wet steam.
If the steam is still being given extra heat at a constant pressure point, then the volume will increase and temperature steam will pass through the point of saturation. Steam is commonly called steam up.
Steam heat up has many advantages because it can be transmitted over long distances with little loss of heat, contains a higher thermal energy, and can reduce the impact of erosion on turbine blades because of the water content in steam has been eliminated

Boilers and process of formation of steam
(Working substance flow diagram on the steam generator)

Internal circulation boiler

There are three types of internal circulation:
1. Forced (economizers) forced circulation (pipe economizer)
2. Natural (wall, roofs, generating section) natural circulation (the pipe wall)
3. Steam pressure difference (superheaters) circulation by pressure difference (steam piping up)

Circulation water / steam in the boiler
Forced circulation

In forced circulation, fluid (feed water) is pumped through the evaporator kettle. Water filler (feed water) can be pumped using only a small pipe
However, with very high pressures (in our boiler reaches about 100 bar).
High pressure forcing fluid flow in through the control valve to the economizer to be forwarded to the steam drum.

Natural circulation

The heat energy given to the combustion chamber will cause evaporation.
The steam has a lower specific gravity will rise upwards, while the heavier water will collect at the bottom of the steam drum (steam drum). Water is what will go down from the steam drum through the downcomer and enters the tube wall (wall tube boiler) natural (gravity)

Circulation pressure difference

As the laws of gravity and heat flow, vapor always flows from an area
Higher pressure to areas of low pressure. Steam in the steam drum of about 12 bar higher than the pressure of steam turbine header. This pressure difference causes the steam flow to the steam pipe up.

2. Type boiler combustion system based

1. Fixed bed (cb)
Do not have a sand layer with temperature (~ 750oc 900oc) in the bottom of the combustion chamber for burning media.

2. Fluidized bed boiler
Boiler wearing hot sand (800 ~ 900 oc) in the furnace. Fluidization
Using primary air of paf.

2.1. Bubbling fluidized bed boiler (BfB):
Bed experienced bubbling (centered) on the bottom of the boiler, bed material
(Sand) remain in the furnace

2.2. Circulating fluidized bed boiler (CFB):
Bed material moving / flying from the combustion chamber and circulating
Back to the combustion chamber with the aid of cyclone separator.

2.1 fixed bed boiler (cb)

The general condition of fixed bed boiler

smaller combustion area.
smaller boiler capacity
Efficiency lower combustion

1. Control fuel with air particles less than perfect
2. O2 (excess water) 3% ~ 10%
3. High carbon content in the ash residue.

Fuel type limited (especially bio-fuel)
The process of burning fuel down drastically if wet (because no charbed that retain heat combustion chamber)
No need oil for start-ups
lower operating costs

2.2 fluidized bed boiler. Bubbling fluidized bed boiler (BfB)

Bubbling fluidized bed boiler (BfB)
1. Bed material (sand) had bubbling (move / swirl) in the bottom of the engine, only a small portion of fine sand with a low specific gravity to fly left the combustion chamber.
2. Fluidization / bubbling is due to the primary air flow passing through the nozzle (on the whole) the basis of the combustion chamber with a speed of 2 ~ 3 m / sec.
3. At rest, the height of the sand combustion chamber is 45 ~ 75 cm from the bottom (nozzle). If the conditions of hot sand floating 90 ~ 150 cm.

Bubbling fluidized bed boiler (mb)

Bubbling fluidized bed boiler (pb)

2.2 fluidized bed boiler
Circulating fluidized bed boiler (CFB)

fluidization achieved with the primary air flow passing through the nozzle at the base of the engine, at a speed of 2 ~ 3m/detik sand still experiencing turbulence statically.
If the air velocity increased until reaching 5 ~ 6 m / sec will be circulating sand.
Bed material (sand) moving / swirling and some flew out of the engine and circulates back into the combustion chamber with the aid of cyclone separator.

Circulating fluidized bed boiler-CFB (mb)

Cyclone separator in mb

Specifications bedmaterial (sand) boiler

1. Sand for boiler BfB

Particle size = 0.5 ~ 2 mm
Density sand = 1.3 ~ 1.6 t/m3
Heat resistance> 1100 ° c

2. Sand for CFB boiler

Particle size = 0.13 ~ 0.6 mm
Sand density = 1.3 ~ 1.6 t/m3
Heat resistance> 1100 ° c

2.3 advantage fluidized bed boiler

larger boiler capacity (pressure & high temperature)
wider area burning, high heat transfer.
flexible fuel type, can change or mix and be able to
Using high moisturenya fuel.
High Efficiency burning and easy to control
Excess lower o2 (2 ~ 6%).
Environmentally friendly:

- The amount of carbon in the fly ash is lower.
- SO2 can be reduced by limestone injection
(SO2 + CaCO3 à gypsum)
- Low nox emissions due to higher combustion temperatures (750 ~ 900oc)

Type boiler in Sumatra

3. System maintenance boiler

New Boiler / renovation of boiler tube

- Alkali boiling
- Magnetic films formation
- Steam flushing

Routine care (internal treatment)

- Boiler water treatment system
• Corrosion control
• Scaling control
• Carry over control
- Trouble shooting (water quality)

3.1 Alkali boiling

Aiming to dispose or release a total carat, solids are sticky on the inside of the tube, minerals and oils and other substances that are not expected to be in the tube / drum.

Chemical needed for boiling alkali:
Soda ash / sodium carbonate (Na2CO3) =>
Total consumption 7.5 kg/m3 boiler volume.

Trisodium phosphate (na3po4) =>Total consumption 7.5 kg/m3 boiler volume.Chemical injection point:
Some through another drain economizer
Mostly through boiler blow down

The general procedure alkali boiling

1. Before the ignition process begins, boiler water recharge and do blow down several times, to remove dirt from sticking to the tube.
2. Fill the water boiler to normal levels, start ignition, an increase in temperature in the furnace or boiler water carried out following the curve of refractory curing.
3. When the water temperature reaches 90oc boiler and furnace temp. 90oc ~ 110oc conducted chemical charging through eco drain and blow down boiler.chemical directly charged to the end (+ 1 hour).
4. Perform chemical circulation for 7 ~ 10 hours, keep your furnace controls the temperature and press the starting valve.
5. Further raising the furnace temperature up to + 200oC and pressure (press) 7 ~ 10 bar, keep this condition for 10 ~ 12 hours.
6. Perform Circulate water blow down and boiler. Furnace temperature, drum press and steam drum level is maintained in accordance point 5, do the test water quality during blow down every 2 hours until normal parameter values.

Parameter test in boiling alkali

Sat Parameter Standard Remark
1. Coductivity
2. Ph
3. Phosphate (na3po4)
4. Silica (Si02)
5. Iron (fe)
6. Oil content Us / cm
-
-

Ppm
Ppm
Ppm <150
9.5 ~ 10.5

<3:50
<0.02
UDT

Standard operational
Eachs boiler

Remarks: if the above conditions have been achieved, the process can stop boiling lye.

3.2 Magnetic films formation

Boiler pipes made of stainless steel or mild steel mix. Once done boiling alkali, the conditions inside the boiler piping clean and very sensitive to corrosion. So to protect the surface of the pipe and prevents corrosion, is necessary to form a protective layer called "layer magnetic film"

Magnetic layer of the film will not provide total protection to the piping, but with protection against corrosion magnetic films can be reduced, as long as water quality can be maintained.

Magnetic layer of the film will be lost / damaged if the boiler water ph ph lower than when the formation of magnetic film.

The general procedure magnetic films

1. This process is a continuation of prosesalkali boiling.

2. If the process is done boiling lye, then proceed with the formation of "magnetic layer film".

3. Steam pressure is increased up to 35 ~ 40 bar, the pressure is controlled with a starting valve / steam to the mp header.

4. Ph in the process of measuring magnetic films approaching ph = 7 (normal ph), then do the test water quality parameters until all water boilers, steam as standard normal operations except ph bw remain near ph = 7, the process is carried out for 36 ~ 38 hours.

Reaction movie kimiamagnetic

With clean water and free oxygen reaction will occur below the
Different temperatures

At temperatures <60'c
2H2O + Fe fe (oh) 2 + h2

Reaction formed can not protect the steel from corrosive.

At temperatures of 60'c ~ 250'c2H2O + Fe fe (oh) 2 + h23fe (oh) 2
2H2O + H2 + Fe3O4 + 4H2 magnetic layer of the film has begun to take shape through 2 faseferro hydroxide.

1. At temperatures 250'c ~ 570'c
3fe + Fe3O4 + 4H2  4h2o
Film magnetic layer harder than the layer formed at low temperatures to protect the pipe from corrosive reaction.

Graph magnetic films formation (for example mb-12 for 32 hours)

3.3 Steam flushing

Aiming to clear the superheater tube & pipe line of solid material objects contained within the pipes that arise during manufacturing / development boiler. Solid objects such as: rust, powder grinding, sand, dirt, etc. should be cleaned so as not to damage the turbine blades.

The general procedure steam flushing:

All internal equipment drum demister, cyclone separator should be opened and removed the condition of the steam drum.

At around steam pipes, made after playing steam outlet valve to blow out blow out steam installed on the target plate of aluminum.
Steam fastest flushing done 1 x 4 hours, performed repeatedly until the inside of the boiler tube really clean, marked by conditions of the target plate (alluminium) no longer a solid object goresan-goresan/rusak severe beating.

Internal maintenance (routine) boiler
1. Routine maintenance (internal check)

System boiler water treatment

- Corrosion Control
- Carry over control
- Deposition / scaling control

Trouble shooting (water quality)

Boiler water treatment system

Things that need to be considered for the water boiler is hardness, chloride salts, silica and acidity and alkalinity of the gases dissolved in the water should not be ignored, such as co2 and o2

Boiler water treatment purposes

1. Prevent corrosion in boiler systems
Corrosion occurs due to the presence of:

Oxygen
Ph of water is too low / too high

2. Prevent deposition / scaling
scaling the result of minerals, especially ca, mg, the
(Deposition in boilers, especially in areas that have a high heat flux).

3. Prevent contamination of steam carry over
As a result of:

Water Impurities charging
parameter limits too far

CORROSION CONTROL

Prevention of corrosion in boiler systems

OPERATION OF VACUUM SYSTEM

noreply@blogger.com (Anonymous) — Mon, 15 Apr 2013 09:22:00 -0700

3.6.1 Start Vacuum System

To arouse a vacuum in the evaporator used a tool called Ejector.

If Black Liquor is charged each effect and Cooling water was circulated on Surface condensers and after / inter condenser, the vacuum system can be operated with the following procedures:

1. Open the manual valve inlet Primary and secondary steam ejector

2. Open the manual valve inlet vapor ejector Hoging

3. Open the manual valve inlet steam ejector hoging

4. Close bypass valve vacuum breaker

5. If the vacuum in the PF-6 has been achieved -700 mbar Hoging cap ejector and ejector Primary and secondary roads remain

Figure 3.13 Operation of Vacuum System

3.7 Procedure Start Evaporator

1. Charging Black Liquor into effect

• Start the pump WBL Feed

• Set the flash tank feed flow to approximately 30% of the design by adjusting the control valve WBL feed

• Raise the level of PF-6 to 80% and then start the circulation pump PF-6.

• Start Transfer pump PF-6 and set the level controller with set point 50% of auto

• Then Black Liquor will go to PF-5, and repeat the procedure as PF-6 for each effect 5, 4 effect, effect 3 and effect 2,

• If the Black Liquor has reached PF-2, select the PF1 sequence (eg ABC) and the valve-open valve in accordance with the order of sequence.

• Start Transfer pump PF-2 and set the level of 50% Auto

Figure 3.14 Cycle Black Liquor from WBL tank to the PF-2

• Raise the level of PF-1A to 80% and then start the circulation pump PF-1A

• Setting the level of PF-1A 50%

• Perform the same procedure for filling PF and PF-1B-1C

• Black Liquor Spill circulated to the tank or tank WBL

Figure 3.15 Cycle Black Liquor on the PF-1A, PF-1B,-1C PF, PF-1D

2. Operation of Steam and Condensate LP

If the vacuum in the PF-6 has been achieved -750 mbar the LP steam to PF-1 can dibuka.dengan following steps:

1. Make sure the vapor control valve to open ABC PF-1 to approximately 50%

2. Make sure the condensate level pot for PF-normal 1ABC Auto position set point 50%

3. Make sure the condensate flash tank pump ready and conductivity meter to function properly

4. Open the Manual Valve LP steam for PF-1ABC 100%

5. Open the LP steam control valve for PF-1ABC approximately 20% or LP steam flow set around 20 tonnes for each Effect 1ABC

6. Set desuperheater control valve to the Auto position set point around 135 s / d 140oc

7. If the condensate level has appeared in Flash Condensate tank, start the pump and condensate pump control valve set to 50% of auto

8. Change the position of the on-off valve condensate to Sequence

9. If steam has entered the Effect 1 then evaporation will occur at each effect and the condensate will occur

10. If an indication of the level of the Clean condensate flash tanks have emerged, Start clean condensate flash tank pump, then set Auto level controller to position the set point of 50% and set the on-off valve to the position of Sequence.

11. Note the level on Foul condensate flash tank, if the level has emerged pump start Foul condensate flash tank, then set the level controller to Auto position set point 50%

12. Adjusts the on-off valve to the Sequence (if high conductivity will automatically go to the spill tank)

Figure 3.16 Cycle LP Steam and Condensate in PF-1

Figure 3.17 Cycle Vapor and Condensate

3. Operation Stripper

Stripper is a tool that serves to purify Foul condensate by way of separation of the gases in the foul condensate to be burned again in RB / RC.

• Operating procedures Stripper system:

1. Make sure all equipment is ready to operate on stripper

2. Foul condensate tank pump start and open the outlet valve of the field manual

3. Open the control valve to the foul condensate Striping column and set the flow to approximately 70 m3 / H

4. If the level has appeared at the bottom of the stripping column start stripping column and set the pump control valve position set point Auto with 50%

5. Open Black Liquor incoming Reflux condenser (with manual valve open inlet and outlet reflux condenser).

6. Open the control valve outlet NCG Trim condenser approximately 25% and manual valve inlet flame arresters and make sure the path is open all the way NCG NCG burner or by pass into the atmosphere.

7. Open warm water condenser inlet and outlet Trim

8. Open the LP steam or vapor into stripping column as needed or loaded with foul condensate ratio to 1:5 ton steam

9. Start pumping condensate pot if indications have appeared on the tank level and control level set to Auto position set point of 50%.

10. Set out with a press NCG NCG set the control valve

Figure 3.18 Process flow on Stripper

3.8 Personal Protective Equipment

Personal Protective Equipment used in the field Vacuum Evaporator:

1. Helm

2. Protective Goggles

3. Gloves

4. Protective Shoes

see also previous article"Vacuum Evaporator"

Maybe useful.

BBM STILL AGAINST OVERWHELMED WHATSAPP

noreply@blogger.com (Anonymous) — Wed, 20 Mar 2013 21:32:00 -0700

BlackBerry Messenger ( BBM ) app store may be topping the App Store and Google Play Store to subvert its competitors , WhatsApp . But actually , WhatsApp still excel far above the fuel .

WhatsApp now is cross- platform messaging service that is most widely used . CEO WhatsApp , Jan. Koum , stating that WhatsApp active users has reached 350 million .

The fuel itself is quickly dashed when released for Android and iOS . Number of downloads reached 10 million times in the first 24 hours and now announced penetrate 20 million .

Coupled with BBM in BlackBerry users reached 60 million , total fuel-consuming almost touched 100 million . But the difference is still hundreds of millions of WhatsApp .

" Monthly active users on BlackBerry , Android , and iPhone , has reached 80 million users . Thank you for your support during this , " said Head of BlackBerry Messenger , Andrew Bocking . BBM can be superior to the WhatsApp app store because that is measured is the number of downloads in certain period of time , instead of total download

If the growth of cross- platform BBM users keep on racing and not slow down drastically , it is not possible fuel capable of beating WhatsApp . But for now , WhatsApp is superior about the number of users , with a gap far enough .

SAMSUNG PREPARE GALAXY S4 ACTIVE MINI VERSION

noreply@blogger.com (Anonymous) — Wed, 13 Mar 2013 21:24:00 -0700

Variants of the Galaxy S4 would soon be increased . Because , Samsung reportedly is reportedly preparing another mini version of the flagship smartphone in the series GT - I8580 .

So , what's the difference with the Galaxy S4 Mini that was first marketed ? As quoted from Phone Arena , Wednesday ( 30/10/2013 ) , the GT - I8580 reportedly is a mini version of the Galaxy S4 Active . That is , the Galaxy S4 Active Mini version is supposedly also going to have the ability to withstand water and dust .

This news was confirmed when the Galaxy S4 Active Mini said to have been given the green light by the FCC to enter the production process . Even so , it remains unclear when the GT - I8580 will begin to be produced by Samsung .

Regarding the specifications, 400 Snapdragon processor clock speed of 1.2 GHz predicted strong will fill the kitchen spur . As for its RAM capacity is 1 GB . The size of the screen itself has a span of 4.65 inches and just rely on measuring 800x480 pixel resolution .

Sector camera was not very special because only equipped with 5 MP capabilities . For the operating system , the Galaxy S4 Active mini will be powered by Android 4.2 Jelly Bean .

With Active GS4 specifications are fairly ordinary Mini , Samsung seems to want additional dredge in the middle segment users who want a phone with the ability to withstand water and dust , but with a more affordable price alone .

DRINKING DRUGS CAN BE DEADLY BY ORANGE JUICE

noreply@blogger.com (Anonymous) — Sat, 9 Mar 2013 09:53:00 -0800

Eating grapefruit and some other citrus fruits are known to cause adverse reactions when combined with certain medications. The most recent research indicates, this risk is far greater than previously thought.

Research published in the Canadian Medical Association Journal stated, grapefruit and some other citrus fruits can cause death, acute renal failure, failed lungs, intestinal bleeding, and other serious health problems due to interactions with certain drugs.

A total of 85 drugs reported to interact with grapefruit, and 43 of which can cause serious side effects.
This reaction is due to the active ingredients in fruit that is a compound called furanocoumarin inhibit the action of enzymes in the body. In addition, these compounds can also increase the dose of the drug to be several times as much, which can cause overdose. In addition to grapefruit, other citrus fruits such as lemons and oranges also contain a compound furanocoumarin byword.

Drugs that can interact with other compounds in grapefruit include anti-hypertensive drugs, anti-cancer drugs and anti-cholesterol drugs.

Dr.. David Bailey, a Canadian scientist says, "although side effects are harmless enough, but grapefruit can also help to a certain type of treatment. But recently claimed discovery of the negative effects of grapefruit on drugs increased from 17 to 43 drugs during 2008 to 2012. This makes the increase is more than 6 drugs per year. "
Bailey added, "current knowledge about drug and food interactions are still lacking, both healthcare practitioners and patients."

For drugs with a low effect, furanocoumarin can increase the effect. But for drugs with effects already high, furanocoumarin instead will lead to over dosage up to 330%.

Dikarena the high risk in using grapefruit or other citrus in raising the dose of medication, then its use can not be done in general practice. "Understanding is very important, so that both doctors and patients should be cautious in utilizing grapefruit effect," said Bailey.

TRY 10 ENGINEERING STRESS RELIEVERS FROM VARIOUS COUNTRIES

noreply@blogger.com (Anonymous) — Sat, 9 Mar 2013 09:51:00 -0800

Whatever civilization and the condition of a nation, all of them must have experienced stress, although the term may vary. Stress is a condition in which the body's mental and physical pressure. And prolonged stress is not managed properly can lead to depression.

There is a proverb that reads Other Other Field Grasshopper, Other Other Lubuk The fish. That is, each region has a different way to handle the problem. The way it is generally based on tradition and local culture, but later became a habit that conserved.

As reported by Health.com, on Monday (26/11/2012), here are the ways of the various countries of the world to relieve stress.

1. Petit Aperitif in France

After the move and under stress, the French used to relax by doing petit aperitif, which is a small ritual by drinking a glass of wine accompanied by cashew nuts or chips, hummus and olive oil. The next thing to do is cook dinner.

Grape known in Europe has a relaxing effect. But more important is the ritual to separate the chaos at work from the comfort of home. Every ritual is carried comfortably can eliminate stress, both light exercise and talking with friends.

2. Sauna bath in Russia

To relieve the stress, the Russians are often gripped by the cold will do the sauna or steam bath using hot water. Just sitting in the extreme heat with sweat washing the body is able to be healers soul.

Warm bath or a hot steam bath not only create a warm hug skin, but a study from Yale University suggests that the warmth of the hot water vapor can trigger the brain and the body's response to emotional warmth and improves mood. Limit the sauna for 10 minutes to avoid dry skin.

3. Been to Home Friends Ala Denmark

Danish people to relax in understated enough friends or relatives house at night and weekends. The important thing is being happy at home and did not rush to go anywhere.

Create a party, the key is also simple, do not bother. If worried invite others to a party that had a perfect holiday, then the stress will also appear. Then weekends only meeting simple, usually enough desserts and beverages served.

4. Massage in Thailand

Thailand seems to have a similar tradition with Indonesia to relieve stress, ie massage. Massages are performed also similar, which is done with a strong, plus the pressure through the knee and elbow to eliminate stress.

Massaging the base of the neck and the surrounding area will release the hormone serotonin, a natural antidepressant. This effect will be even more powerful if asked couples doing the massage.

5. Drinking Mate in Argentina

In Argentina, there is a drink called mate, which circulated hot herbal drinks with friends like peace pipe on the Indians. It made the people so connected with the group and lowers stress.

According to a study in Belgium, eat or drink with a soothing release the hormone oxytocin. The existence of strong ties with the group would make someone be appreciated by others in the vicinity.

6. Laughter exercises in India

Every morning, several people in India do exercises laughing with smiling, waving and jumping. The more often this exercise is done, the better the resulting mood.

When laughing, the abdominal muscles to contract and trigger endorphins that make you feel better feelings, according to research from the University of Oxford. Laughed for a few minutes alone can soothe. Therefore, it is better to record a show or event humor favorites to watch again the night after the move.

7. Walk in Ireland

In cold weather though, in Ireland will remain often found people walking around outside with the kids. This method can be trusted to 'turn on' the brain back and give energy.

A study in 2012 found that people who rode a stationary bike for 30 minutes and then look at the photos turned out to be less anxiety disturbing than people who just sit quietly. It turns out exercise not only reduces anxiety, but also helped create a feeling of calm when faced with distressing events.

8. Together coffee in Sweden

In Sweden, there is a term called fika, the rest with a cup of coffee with friends. This little ritual has become part of the culture there since the 1700s. In many companies, employees do fika at about 10 am and 3 pm to go to a cafe drinking latte, tea or smoothie accompanied cinnamon, muffins, or macaroni.

Fika create a comfortable and peaceful feeling. A study conducted Massachusetts Institute of Technology found that people who socialize towards the end of the work day will be more productive than the 10-15% that do not socialize.

9. Foot soak in China

Chinese people used to soak feet in a large pot of hot water or referred to as 'yu zu' before bed. Usually done while sitting on the couch while reading a book or surfing the internet to fall asleep.

Ankle foot soak up the hot water is added salt and 2 tablespoons baking soda for 15 minutes can reduce swelling and improve blood circulation. In addition, the effect can also be soothing.

10. Keyif in Turkey

Turkish people used to do Keyif, it means enjoying pleasant things. Can practice by listening to music or straighten the legs and not think about anything that causes stress.

Stressful thoughts often come from the assumption that something bad will happen. If you can focus on the positive, negative thoughts trigger stress will disappear or at least diminish. One study found that people who were given a cold compress will greatly diminished sense of comfort when disambi not listen to music.

TOO LITTLE OR EQUALLY MOST DANGEROUS SPORTS FOR KNEE

noreply@blogger.com (Anonymous) — Thu, 7 Mar 2013 09:49:00 -0800

Lack of physical activity in middle age may cause the deterioration of cartilage in the knee and the risk of knee osteoarthritis. But based on research, too much physical activity in this age also have the same risks.

A new study says that high levels of physical activity and low, they may accelerate cartilage damage to the knee in adults who have middle-aged.

Researchers at the University of California San Francisco (UCSF) have previously found an association between physical activity with cartilage degeneration. However, the study only focused on one point of time.

UCSF researchers see changes in knee cartilage in a group of middle-aged adults during the 4-year study period. Researchers used magnetic resonance imaging (MRI)-based T2 relaxation time (part-time) to track the evolution of early degenerative changes in the knee cartilage.

"T2 relaxation time produced by MRI allows for the analysis of biochemical and molecular composition of cartilage. An increase in water mobility in damaged cartilage, and the resulting increase in water mobility increased T2 relaxation time, "Wilson said Lin, who led the study.

Researchers analyzed 205 patients aged 45 to 60 years, from UCSF Osteoarthritis Initiative, a national study funded by the National Institutes of Health for the prevention and treatment of knee osteoarthritis.
Participants were asked to fill out questionnaires to record their physical activity then researchers measured T2 values of cartilage in the femur, tibia and patella of the right knee joint at baseline, 2-year and 4-year study at the end of the study.

According to the study, people who often participate in sports such as running with high intensity, have been associated with a more degenerate cartilage and increased risk for development of osteoarthritis.

7 SIGNS YOUR OBSESSION ON SPORTS CAN BE DANGEROUS BODY

noreply@blogger.com (Anonymous) — Wed, 6 Mar 2013 09:42:00 -0800

Maintain health and fitness to sports or physical exercise is very important. But if exercise is done too much to memforsir power, which happens not to be healthy but health problems. These are the signs you exercise excessively and should be immediately wary, quoted from Time Gal.

1. Not Compromise on Health

There are times when the schedule is very solid routines so hours of sleep is reduced and the body was not fit. If you are experiencing now feel guilty for not being able to exercise, it is a problem that must be avoided. When you are injured, have a fever or lack of sleep but still think going to the gym is very important, it has become a problem that must be addressed. Regular exercise is necessary, but not what the occasional sports schedules passed.

2. Exercise is a Liability

Although the workout at the gym can make you feel happy, but it should not be a liability. Do exercise at intervals should be, because if it is too demanding it every day then it is not fun anymore training activities.

3. Calorie is the Enemy

If every time you eat foods calculate how long it takes to burn calories back, then maybe you are obsessed. Avoid the need not worry too much about calories into the body because the body also needs calories for energy.

4. Down Drastic Weight Loss

Someone who are obese tend to lose weight drastically when beginning a diet and exercise. In fact, the weight loss of more than 1.3 kg per week then it means you push yourself too hard.

5. Not Balanced

Do not get a solid workout schedule snatch happiness because it must pass through a preferred activity. Take the time to socialize with friends or family because it is not as important as exercise.

6. Prone to Injury

People who are prone to diligent exercise because muscle injury that kept working. If the center was injured, do not force yourself to exercise regularly but istirahatkanlah yourself so that you can recover health.

7. Run out of steam

Sports provide power is indeed a fact. However, if excessive exercise will harm you.

WHAT IS THE RECOVERY BOILER?

noreply@blogger.com (Anonymous) — Sun, 12 Aug 2012 03:19:00 -0700

Definition Recovery Boiler

Recovery Boiler A boiler is a special unit used to purify the compound - an organic chemical compounds contained in Black Liquor (waste cooking from the digester) and at the same time as high-pressure steam generator (High Pressure Steam).

Heavy Black Liquor (70% solid) containing:

An organic compound with the main content of Na2CO3, Na2SO4, NaOH, Na2S.
Organic compounds derived from wood during cooking in the digester in the form of wood fibers, ligmin
Water
Heat energy contained in the Heavy Black Liquor range 3100 - 3500 kcal / kg dry solid.
Heat energy is partly used to convert the organic compounds and partly used as fuel to generate steam
Heavy Black Liquor Evaporator Vacuum produced by the input to the Mixing Tank, in the mixing tank mixed with combustion ash from ESP (Electrostatic precipitator) and-1 from the economizer, economizer-2, Boiler Bank, then added with salt cake (Na2SO4 powder).
Once mixed in the Mixing Tank, Heavy Black Liquor (HBL) is sprayed into the furnace to burn through the spray gun. Prior to the furnace going process of drying by blowing hot air, then collects in the bottom of the furnace to form charbed and caught fire after reaching the point of combustion.
Combustion air needs exhaled through the Primary, Secondary and Tertiary wind boxes located around the bottom of the furnace wall.

To start combustion in the furnace as well as to stabilize the combustion conditions, use of diesel fuel is sprayed through a burner into the furnace.
During combustion, the following process takes place in the furnace are:
1. The compound - organic compound burning releases heat and partly turned into a gas.
2. Sodium sulphate (Na2SO4) contained in the HBL and the salt cake is reduced to a compound of sodium sulphite (Na2S)
Na2SO4 + 2C + 2 Co2 Ns2S
The speed reduction is calculated:
Reduction Rate: Na2S. X 100%
Na2S + Na2SO4
3. The compound - an organic compound called Smelt melt like lava.
If the conditions of combustion is complete, reduction rate reached> 95%
A melt of organic chemicals (smelt) will accumulate around the side charbed smelt spout and flow out into the dissolving tank, where in the dissolving tank, smelt will be dissolved with WLL (WEAK White Liquor) from RC, the mixture of smelt with the WLL-called Green liquor (GL) which is pumped from the dissolving tank RB to RC section for the Recausticyzing be WL (White Liquor) or cooking liquor
For reuse as raw wood cooking in digester (Pulp Making Section)

Time of air and gases - gases of combustion, called flue gas still contains a high amount of heat Energy.
Flue gas is inhaled / drawn by a device called the Induced Draft Fan (IDF), where the flue gas will pass through the pipe - boiler pipe so that water contained in boiler piping briefly - of land become heated and turned into high-pressure steam will then be used for the propulsion of Turbine Generator to generate electrical energy.
So the production side of the Recovery Boiler is STEAM high pressure (60 bar)

Smelt Reduction Efficiency:
Na2SO4 + 2C + Heat ----- Na2S + 2CO2
SRE = Na2S/Na2S + Na2SO4 x 100%
Recauticizing
--- CaO + H2O Ca (OH) 2
Ca (OH) 2 + Na2CO3 --- 2NaOH + CaCO3
CaCO3 + Heat ----- CaO + CO2

History of Recovery Boiler

Kraft Porridge was first developed in Germany in 1870's, in a strong sense in Germany: kraft pulp fiber slurry to produce hard at a short maturation process.
Addition of Na2SO4 will be accelerated with delignification process without reducing the strength of pulp fibers.
Pulp first made in 1909 in the city Roanake Rapids, North Carolina, kraft pulp growing popularity, in 1930 to found the Recovery Boiler is made more economical kraft pulp.
Today kraft pulp about 70% is produced in America.

Feed Water to Steam Cycle Recovery Boiler 6
Demineralizer water (steam PG) Feed Water Tanks economizer economizer 1 2 Dolezal (to RB & RB-6-12) Steam drum bottom of steam drum to the boiler wall piping, furnaces & Steam Boiler drum bank top to the screen tube Primary Secondary superheater superheater Tertiary superheater steam to the turbine generator.

Park Pressure Recovery Boiler
1. Furnace site of a combustion process HBL
2. Superheater is placed over the furnace, and the screen is protected with a nose tube.

Nose is designed to produce flue gas flow pressure of a strong and directed to the superheater, as well as to protect the superheater from the excess. Then superheater which comes from the furnace to the superheater. This event continues from primary superheater, secondary and tertiary superheater superheater.
3. Screen Tube
To avoid direct heat flue gas coming from the furnace to the superheater and the lower the temperature of the furnace by means used by the screen tube.
4. Boiler Bank
Its location is situated behind the superheater.
5. Economizer
Economizer economizer consists of 1 & 2 is the long stream counter flow between the flow of flue gas and feed water

Factors Supporting Recovery Boiler

1. Soot Blowing System
Aims to bring down the soot blowers or clean ash piping attached to the inside of the boiler (superheater, boiler bank, economizer).
RB-6, has 86 sets Sootblower (43 to the left, 43 top right)
2. Medium Pressure Steam
For Air preheater, start-up burner, smelt spout steam shuttering.
3. Low Pressure Steam
For water preheater
4. Condensate
5. Electrostatic precipitator (ESP)
Each RB must be equipped with ESP which is useful for capturing particles - solid particles contained in the flue gas further solid particles (ash) is returned to the mixing tank to be mixed with HBL
RB-5 Equipped with 2 sets ESP
RB-6 & 12 are equipped with 3 sets ESP
RB-11 is equipped with 4 sets ESP

Recovery Boiler is also equipped with security system

1. Interlock System
This system serves to prevent damage in case of irregularities Boiler operating conditions.
2. Safety Valve
This tool serves to keep the boiler pressure does not exceed the limits specified security pressures.
3. Rappid Drain System.
This system serves to empty the water boiler to a minimum label, if there is a severe leakage in the piping boiler causing water to enter into the furnace.
This system operated at the time of emergency and went so fast for Boilers avoid further damage.

RB Quality Control

1. Demineralizer Water Conductivity pH 6.0 ~ 8.0 <5.0 ms / cm 2. Feed Water Conductivity pH 8.0 ~ 9.5 <5.0 ms / cm SiO2 <40.0 ~ 50.0 ppb 10.0 ppb N2H4 3. Boiler water pH 9.5 ~ 10.5 Conductivity <150.0 mx / cm PO4 2.0 ~ 12.0 ppm SiO2 <3:50 ppm 4. Saturated Steam Conductivity pH 7.5 ~ 9.5 <5.0 ms / cm SiO2 <40.0 ppb 5. Steam superheater Conductivity pH 7.5 ~ 9.5 <5.0 mx / cm SiO2 <40.0 ppb 6. Green Liquor NaOH 12.0 ~ 20.0 g / l Na2S 25.0 ~ 35.0 g / l Na2CO3 70.0 ~ 85.0 g / l TSS <1500 ppm 7. Smelt Reduction rate> 95.0%.see also previous article"How does a power plant boiler work?".

HOW DOES A POWER PLANT BOILER WORK

noreply@blogger.com (Anonymous) — Fri, 10 Aug 2012 00:12:00 -0700

This time articel is i will study about how recovery boiler work. after yesterday I was talking about "THE ELECTROSTATIC PRECIPITATOR".The boiler generates high pressure steam by transfering the heat of Combustion in various heat transfer sections. This part of the article series briefly describes the flow and arrangement of the heat transfer sections in a boiler. In line diagrams help make the concept clear. The Basics. Volume of one unit mass of steam is thousand times that of water, When water is converted to steam in a closed vessel the pressure will increase. Boiler uses this principle to produce high pressure steam. Conversion of Water to Steam evolves in three stages. • Heating the water from cold condition to boiling point or saturation temperature – sensible heat addition. • Water boils at saturation temperature to produce steam - Latent heat.addition. • Heating steam from saturation temperature to higher temperature called Superheating to increase the power plant output and efficiency. Sensible Heat Addition Feed Water Pump. The first step is to get a constant supply of water at high pressure into the boiler. Since the boiler is always at a high pressure. ‘Boiler feed water pump’ pumps the water at high pressure into the boiler from the ‘feed water tank’. The pump is akin to the heart in the human body. Pre-Heating 'Feed water heaters’, using extracted steam from the turbine, adds a part of the sensible heat even before the water enters the boiler. Economiser. Most of the sensible heat is absorbed in the Economiser. These are a set of coils made from steel tubes located in the tail end of a boiler. The hot gases leaving the boiler furnace heat the water in the coils. The water temperature is slightly less than the saturation temperature. From the economiser the water is fed to the 'drum'. Pre-Heating & Economiser Latent Heat Addition Drum. The drum itself a large cylindrical vessel that functions as the storage and feeding point for water and the collection point for water and steam mixture. This is the largest and most important pressure part in the boiler and weighs in the range 250 Tons for 600 MW power plant. Water Walls Boiling takes place in the ‘Water Walls’ which are water filled tubes that form the walls of the furnace. Water Walls get the water from the ‘downcomers’ which are large pipes connected to the drum. The downcomers and the water wall tubes form the two legs of a water column. As the water heats up in the furnace a part of the water in the water-wall tubes becomes steam. This water steam mixture has a lower density than the water in the downcomers. This density difference creates a circulation of water from the drum, through the downcomers, water walls and back to the drum. Steam collects at the upper half of the drum. The steam is then sent to the next sections. The temperature in the drum, downcomers and water wall is at the saturation temperature. WaterWalls SuperHeat / ReHeat SuperHeater Steam from the drum passes to the SuperHeater coils placed in the Flue gas path.. The steam temperature increases from the saturation temperature till the maximum required for operation. The superheated steam then finally goes to the turbine.Final Superheater temperatures are in the Range of 540 to 570 °C for large power plants and SuperHeated steam pressures are around 175 bar. Reheater Steam from the exhaust of the first stage turbine goes back to the boiler for reheating and is returned to the second stage. Reheater coils in the flue gas path does the reheating of the returned steam. The reheat steam is at a much lower pressure than the super heated steam but the final reheater temperature is the same as the superheated steam temperature. Reheating to high temperatures improves the output and efficiency of the Power Plant. Final Reheater temperatures are normally in the range of 560 to 600 °C. Reheat steam pressures are normally around 45 bar. SuperHeater / ReHeater The above are the major water and steam circuit items in a boiler and are collectively called the ‘pressure parts’.
see also previous article "What is the electrostatic precipitator ?"
Maybe Useful.

MECHANISMS OF STEAM SOOT BLOWER EROSION

noreply@blogger.com (Anonymous) — Thu, 26 Jul 2012 03:18:00 -0700

There are many mechanisms that can cause steam soot blower erosion of boiler tubes at various heat transfer sections. Knowing the way these mechanisms contribute to erosion will help to prevent loss of availability of boiler.

Soot blowers are provided in boilers at various locations like water-walls, superheaters, reheaters, economizers and air pre-heaters. Steam soot blowers have specific advantage and disadvantages over other types. The advantages being mainly their low capital cost, operating cost and the effectiveness of cleaning in areas like furnace, superheaters and reheaters.

The major disadvantages are they need a higher level of maintenance; effectiveness is low in oil firing mainly in air pre-heater area. They need warm up and condensate draining before startup. The mechanisms of steam soot blower erosion of heat transfer tubes can be a single factor or multiple factors acting individually or in unison. There are much more than hundred soot boilers in boilers generating and supplying steam for a 500 MW and above plants.

Possible mechanisms

All blowers are set to be set at the right steam pressure recommended by the designer if this is not done then it leads to poor cleaning or higher rate of tube erosion due to high steam pressure. This is true for all soot blowers in the boiler starting from furnace to air pre-heater.
The alignment of the blower with respect to the furnace walls, superheater tubes, reheater tubes, economizer tubes and air pre-heater tubes or elements is very critical and not maintaining this leads to erosion of the tubes and subsequent metal wastage. The thinning of the tubes finally leads to pinhole failures and many secondary figures due to this depending upon the orientation of the leak.
It is required to ensure at least 50 degree centigrade of super heat in the steam being used for blowing. If the super heat in the steam is lower than required then during blowing wet steam impinge the tubes at high velocity and the impact force damaging the heat transfer tubes. This can be identified by the typical spit like metal wastage on the tubes surrounding the blower’s area of effectiveness.
The duration of operation of blowers is another main reason for erosion of the heat transfer tubes. Even if you maintain the correct pressure and temperature the erosion will take place at a slow phase if duration is more than required.
In coal fired boiler if alignment is not correct then the ash deposits being cleaned can get entrained and cause erosion of tubes. However in oil fired boilers it is not a mechanism that can happen due to the fact that the ash in oil is not significant at all.
The higher frequency of operation of the soot blowers than needed also leads to tube erosion.
Optimizing the soot blower operation is important as operating those blowers where deposits are not there or very low will lead to metal wastage over a period of time.
Failure to drain the condensate in the soot blower steam pipes is also contributing mechanism of tube erosion. The condensate gets entrained in the steam while the blower operates and has a much higher damaging effect than the lower degree of superheat in steam.

It has been seen in many boilers, mainly coal fired boilers, the soot blower erosion is one of the main contributing factors for loss of boiler availability. In the case of chemical recovery boilers also the soot blowers attribute to the loss of availability of boiler in a significant way

Soot blowers keep the heat transfer surfaces in a boiler clean. A brief description of the working of soot blowers is given in this article.

Chimney Sweeps have been legendary characters in English literature from Hans Christian Anderson to Charles Dickens. In the earlier days when houses had fireplaces, the Chimney Sweep did the function of cleaning the soot from the chimney. In the modern day boiler, the soot blower does the same function.

In oil fired boilers, over a period of time the heat transfer tubes get covered by a layer of soot or fine carbon deposit. This reduces the heat transfer from the hot gases to the water and reduces the efficiency of the boiler.

In coal fired boilers, the furnace area gets covered by slag which is molten ash. The ash also sticks to the heat transfer surface in the other heat transfer areas. These ash accumulations reduce heat transfer and increase the tube metal temperatures leading to failure of the tubes.

Tube cleaning is done periodically to remove the ash or soot deposits. Steam is the medium used for cleaning. The steam is taken from the boiler itself.

The soot blower consists of a lance tube with a nozzle at the end. When it is operated, the lance is extended into the boiler and steam is admitted through the lance. The steam comes out as a high velocity jet through the nozzles, which cleans the ash deposited on the surface. When the lance moves into the boiler it is also rotating so that it cleans the sweeping area covered by the circular travel of the nozzle. The lance is then retracted back.

There are two types of soot blowers.

One with a very long lance called the “long retractable soot blowers.” This is normally used to clean the ash deposit from between the coils of superheaters and economisers.

The other type is the shorter lance type called the “wall blowers.” These are used to clean the furnace walls. The lance extends a short distance around 200 mm from the furnace wall. The nozzle direction is such that the steam impinges on the walls cleaning the surface. During operation, the lance rotates cleaning the radial area covered by the steam from the nozzle.

The deposits on the walls are due to the chemical constituents of ash, and the amount of combustion air. If the ash contains more of Ferrous Sulphide, then the melting temperature of the ash is low which makes the ash melt and stick to the walls.

A large coal fired Thermal power plant will have around two hundred soot blowers of both types arranged to cover all the area of the boiler. This will be programmed to automatically operate to a required sequence.

Intelligent soot blower systems calculate the trends in the temperature increase in different sections of a boiler. The program then decides which soot blowers have to be operated and at what frequency.

High-pressure water lances are also used in some units where the slagging is very heavy.
see also previous article "What is the black liquor?"

May be useful.

FURNACE CAMERA

noreply@blogger.com (Anonymous) — Mon, 23 Jul 2012 10:51:00 -0700

This day i will taking about Furnace Camera.As the current technological developments in power plant technology especially the use of recovery boiler is constantly innovating in order to complement the existing deficiencies in the means of production to facilitate the operation of the recovery boiler.

Currently the power plant that uses a recovery boiler there is a lack of technology to the unavailability of a device to control the conditions inside the boiler (furnace). So far the recovery boiler operator can only monitor the condition of the inside of the furnace manually just by looking at the field by controlling the air of room pannel (dcs). but that's not enough data taken with the actual data. accuracy conditions may only be 65% to monitor conditions inside the furnace charbed.

Camera Enclosure with Lens

The above shows what is removed and store during shutdown or repair

Camera Enclosure Interior

Back of camera core

Removing Camera Core

Camera Retract system

Camera Port

Cleaner

Control Enclosure

Solenoid valve assembly

(Inside control enclosure)

Valve Manual override

Siemens LOGO PLC

Settable Parameter available from key pad on Logo:

Cycle time (time between cleaning cycles)

Cleaning stroke time (time energized and de-energized

Number of cleaning strokes

Pneumatic System

Lens tube/manifold pressure to be maintained between 1.5 and 2 BAR

Input pressure to the system should be 5 and 12 bar

The cleaning cylinder (with check valve) acts as an accumulator to retract camera in the event of a line failure.

System Faults and General Maintenance

LENS CLEANING

The most common form of maintenance on the camera lens system will be cleaning the “objective” lens – that part of the lens system furthest from the camera. Periodic, daily cleaning of the objective lens should be expected, although cleaning intervals of 5 or 6 days are not un-common.

A dirty objective will produce an image that is fuzzy or appears out of focus. The part of the objective that requires cleaning is the protective clear sapphire window, which is very hard and difficult to inadvertently scratch, but relatively easy to break.

Warning:

Do not attempt to clean a hot lens! The objective lens assembly must be below 110°F or comfortable to the touch before cleaning.

To clean the objective lens sapphire:

Retract the lens by selecting “RETRACT” at the control enclosure.

Allow the lens to cool for several minutes.

Once cool (relatively comfortable to the touch), turn the supply air to the lens system off at the shut-off valve.

Using a cotton swab and alcohol, reach into the end of the lens assembly and clean any dirt or oil that may have collected on the objective sapphire.

Char build-up on or around the lens tube should also be cleaned at this time.

Turn the supply air on.

Most Faults and the probable reason for the fault are broadcast on the face of the Control Panel

The camera has 30-seconds to cool down once an overtemp

Situation is discovered.

There are three different faults that will cause the camera to retract:

Camera enclosure over temp - temporary over temp recognized

Camera has retracted and then cooled to operating temp check air supply and for combustion air leaks

Camera over temp - system is shut down

Camera retracted and failed to cool within 30 seconds camera has been shut off as result to avoid damage. Check air supply and cooler adjustment.

Low air pressure – camera retracted to avoid overheating

Check for compressed air leaks and ball valve position

Retract limit fail – automatic cleaning not possible

Important to keep the retract cleaned and lubricated so if a overtemp condition occurs the retract can do what it is supposed to do

Output fail check fuse 1

Output fail check fuse 2

Output fail check fuse 3

There are three different ouput faults that are monitored

Maybe usefull.

WHAT IS THE BLACK LIQUOR?

noreply@blogger.com (Anonymous) — Sun, 8 Jul 2012 03:19:00 -0700

Concentrated black liquor contains organic dissolved wood residue in addition to sodium sulfate from the cooking chemicals added at the digester. Combustion of the organic portion of chemicals produces heat. In the recovery boiler heat is used to produce high pressure steam, which is used to generate electricity in a turbine. The turbine exhaust, low pressure steam is used for process heating.

Combustion of black liquor in the recovery boiler furnace needs to be controlled carefully. High concentration of sulfur requires optimum process conditions to avoid production of sulfur dioxide and reduced sulfur gas emissions. In addition to environmentally clean combustion, reduction of inorganic sulfur must be achieved in the char bed.

The recovery boiler process has several unit processes:

Combustion of organic material in black liquor to generate steam
Reduction of inorganic sulfur compounds to sodium sulfide, which exits at the bottom as smelt
Production of molten inorganic flow of mainly sodium carbonate and sodium sulfide, which is later recycled to the digester after being re-dissolved
Recovery of inorganic dust from flue gas to save chemicals
Production of sodium fume to capture combustion residue of released sulfur compounds

First recovery boilers

Some features of the original recovery boiler have remained unchanged to this day. It was the first recovery equipment type where all processes occurred in a single vessel. The drying, combustion and subsequent reactions of black liquor all occur inside a cooled furnace. This is the main idea in Tomlinson’s work.

Secondly the combustion is aided by spraying the black liquor into small droplets. Controlling process by directing spray proved easy. Spraying was used in early rotary furnaces and with some success adapted to stationary furnace by H. K. Moore. Thirdly one can control the char bed by having primary air level at char bed surface and more levels above. Multiple level air system was introduced by C. L. Wagner.

Recovery boilers also improved the smelt removal. It is removed directly from the furnace through smelt spouts into a dissolving tank. Some of the first recovery units employed the use of Cottrell’s electrostatic precipitator for dust recovery.

Babcock & Wilcox was founded in 1867 and gained early fame with its water tube boilers. The company built and put into service the first black liquor recovery boiler in the world in 1929.This was soon followed by a unit with completely water cooled furnace at Windsor Mills in 1934. After reverberatory and rotating furnaces the recovery boiler was on its way.

The second early pioneer, Combustion Engineering based its recovery boiler design on the pioneering work of William M. Cary, who in 1926 designed three furnaces to operate with direct liquor spraying and on work by Adolph W. Waern and his recovery units.

Recovery boilers were soon licensed and produced in Scandinavia and Japan. These boilers were built by local manufacturers from drawings and with instructions of licensors. One of the early Scandinavian Tomlinson units employed a 8.0 m high furnace that had 2.8*4.1 m furnace bottom which expanded to 4.0*4.1 m at superheater entrance.

This unit stopped production for every weekend. In the beginning economizers had to be water washed twice every day, but after installation of shot sootblowing in the late 1940s the economizers could be cleaned at the regular weekend stop.

The construction utilized was very successful. One of the early Scandinavian boilers 160 t/day at Korsnäs, operated still almost 50 years later.

Development of recovery boiler technology

The use of Kraft recovery boilers spread fast as functioning chemical recovery gave Kraft pulping an economic edge over sulfite pulping.

The first recovery boilers had horizontal evaporator surfaces, followed by superheaters and more evaporation surfaces. These boilers resembled the state-of-the-art boilers of some 30 years earlier. This trend has continued until today. Since a halt in the production line will cost a lot of money the adopted technology in recovery boilers tends to be conservative.

The first recovery boilers had severe problems with fouling.

Tube spacing wide enough for normal operation of a coal fired boiler had to be wider for recovery boilers. This gave satisfactory performance of about a week before a water wash. Mechanical sootblowers were also quickly adopted. To control chemical losses and lower the cost of purchased chemicals electrostatic precipitators were added. Lowering dust losses in flue gaseshas more than 60 years of practice.

One should also note square headers in the 1940 recovery boiler. The air levels in recovery boilers soon standardized to two: a primary air level at the char bed level and a secondary above the liquor guns.

In the first tens of years the furnace lining was of refractory brick. The flow of smelt on the walls causes extensive replacement and soon designs that eliminated the use of bricks were developed.

Improving air systems

To achieve solid operation and low emissions the recovery boiler air system needs to be properly designed. Air system development continues and has been continuing as long as recovery boilers have existed.As soon as the target set for the air system has been met new targets are given. Currently the new air systems have achieved low NOx, but are still working on lowering fouling. Table 1 visualizes the development of air systems.

Table 1: Development of air systems.

Air system

Main target

But also should

1st generation

Stable burning of black liquor

2nd generation

high reduction

Burn liquor

3rd generation

decrease sulfur emissions

Burn black liquor, high reduction

4th generation

low NOx

Burn black liquor, high reduction and low sulfur emission

5th generation

decrease superheater and boiler bank fouling

Burn black liquor, high reduction, low emissions

The first generation air system in the 1940s and 1950s consisted of a two level arrangement; primary air for maintaining the reduction zone and secondary air below the liquor guns for final oxidation.The recovery boiler size was 100 – 300 TDS (tons of dry solids) per day. and black liquor concentration 45 – 55 %. Frequently to sustain combustion auxiliary fuel needed to be fired. Primary air was 60 – 70 % of total air with secondary the rest. In all levels openings were small and design velocities were 40 – 45 m/s. Both air levels were operated at 150oC. Liquor gun or guns were oscillating. Main problems were high carryover, plugging and low reduction. But the function, combustion of black liquor, could be filled.

The second generation air system targeted high reduction. In 1954 CE moved their secondary air from about 1 m below the liquor guns to about 2 m above them.The air ratios and temperatures remained the same, but to increase mixing 50 m/s secondary air velocities were used. CE changed their frontwall/backwall secondary to tangential firing at that time. In tangential air system the air nozzles are in the furnace corners. The preferred method is to create a swirl of almost the total furnace width. In large units the swirl caused left and right imbalances. This kind of air system with increased dry solids managed to increase lower furnace temperatures and achieve reasonable reduction. B&W had already adopted the three-level air feeding by then.

Third generation air system was the three level air. In Europe the use of three levels of air feeding with primary and secondary below the liquor guns started about 1980. At the same time stationary firing gained ground. Use of about 50 % secondary seemed to give hot and stable lower furnace.Higher black liquor solids 65 – 70 % started to be in use. Hotter lower furnace and improved reduction were reported. With three level air and higher dry solids the sulfur emissions could be kept in place.

Fourth generation air systems are the multilevel air and the vertical air. As the feed of black liquor dry solids to the recovery boiler have increased, achieving low sulfur emissions is not anymore the target of the air system. Instead low NOx and low carryover are the new targets.
Multilevel air

The three-level air system was a significant improvement, but better results were required. Use of CFD models offered a new insight of air system workings. The first to develop a new air system was Kvaerner (Tampella) with their 1990 multilevel secondary air in Kemi, Finland, which was later adapted to a string of large recovery boilers.Kvaerner also patented the four level air system, where additional air level is added above the tertiary air level. This enables significant NOx reduction.
Vertical air

Vertical air mixing was invented by Erik Uppstu.His idea is to turn traditional vertical mixing to horizontal mixing. Closely spaced jets will form a flat plane. In traditional boilers this plane has been formed by secondary air. By placing the planes to 2/3 or 3/4 arrangement improved mixing results. Vertical air has a potential to reduce NOx as staging air helps in decreasing emissions.In vertical air mixing, primary air supply is arranged conventionally. Rest of the air ports are placed on interlacing 2/3 or 3/4 arrangement.

Black liquor dry solids

Net heating values of industrial black liquors at various concentrations

As fired black liquor is a mixture of organics, inorganics and water. Typically the amount of water is expressed as mass ratio of dried black liquor to unit of black liquor before drying. This ratio is called the black liquor dry solids.

If the black liquor dry solids is below 20 % or water content in black liquor is above 80 % the net heating value of black liquor is negative. This means that all heat from combustion of organics in black liquor is spent evaporating the water it contains. The higher the dry solids, the less water the black liquor contains and the hotter the adiabatic combustion temperature.

Black liquor dry solids have always been limited by the ability of available evaporation.Virgin black liquor dry solids of recovery boilers is shown as a function of purchase year of that boiler.

Virgin black liquor dry solids as a function of purchase year of the recovery boiler

When looking at the virgin black liquor dry solids we note that on average dry solids has increased. This is especially true for latest very large recovery boilers. Design dry solids for green field mills have been either 80 or 85 % dry solids. 80 % (or before that 75 %) dry solids has been in use in Asia and South America. 85 % (or before that 80 %) has been in use in Scandinavia and Europe.
High temperature and pressure recovery boiler

Development of recovery boiler main steam pressure and temperature was rapid at the beginning. By 1955, not even 20 years from birth of recovery boiler highest steam pressures were 10.0 MPa and 480oC. The pressures and temperatures used then backed downward somewhat due to safety.By 1980 there were about 700 recovery boilers in the world.

Development of recovery boiler pressure, temperature and capacity.
Safety

One of the main hazards in operation of recovery boilers is the smelt-water explosion. This can happen if even a small amount of water is mixed with the solids in high temperature. Smelt-water explosion is purely a physical phenomenon. The smelt water explosion phenomena have been studied by Grace.By 1980 there were about 700 recovery boilers in the world.The liquid - liquid type explosion mechanism has been established as one of the main causes of recovery boiler explosions.

In the smelt water explosion even a few liters of water, when mixed with molten smelt can violently turn to steam in few tenths of a second. Char bed and water can coexist as steam blanketing reduces heat transfer. Some trigger event destroys the balance and water is evaporated quickly through direct contact with smelt. This sudden evaporation causes increase of volume and a pressure wave of some 10 000 – 100 000 Pa. The force is usually sufficient to cause all furnace walls to bend out of shape. Safety of equipment and personnel requires an immediate shutdown of the recovery boiler if there is a possibility that water has entered the furnace. All recovery boilers have to be equipped with special automatic shutdown sequence.

The other type of explosions is the combustible gases explosion. For this to happen the fuel and the air have to be mixed before the ignition. Typical conditions are either a blackout (loss of flame) without purge of furnace or continuous operation in a substoichiometric state. To detect blackout flame monitoring devices are installed, with subsequent interlocked purge and startup. Combustible gas explosions are connected with oil/gas firing in the boiler. As also continuous O2 monitoring is practiced in virtually every boiler the noncombustible gas explosions have become very rare.
Modern recovery boiler

The modern recovery boiler is of a single drum design, with vertical steam generating bank and wide spaced superheaters. This design was first proposed by Colin MacCallum in 1973 in a proposal by Götaverken (now Metso Power inc.) for a large recovery boiler having a capacity of 4,000,000 lb of black liquor solids per day for a boiler in Skutskär, Sweden, but this design was rejected as being too advanced at that time by the prospective owner. MacCallum presented the design at BLRBAC and in a paper "The Radiant Recovery Boiler" printed in Tappi magazine in December 1980. The first boiler of this single-drum design was sold by Götaverken at Leaf River in Mississippi in 1984. The construction of the vertical steam generating bank is similar to the vertical economizer. Vertical boiler bank is easy to keep clean. The spacing between superheater panels increased and leveled off at over 300 but under 400 mm. Wide spacing in superheaters helps to minimize fouling. This arrangement, in combination with sweetwater attemperators, ensures maximum protection against corrosion. There have been numerous improvements in recovery boiler materials to limit corrosion.
The effect of increasing dry solids concentration has had a significant effect on the main operating variables. The steam flow increases with increasing black liquor dry solids content. Increasing closure of the pulp mill means that less heat per unit of black liquor dry solids will be available in the furnace. The flue gas heat loss will decrease as the flue gas flow diminishes. Increasing black liquor dry solids is especially helpful since the recovery boiler capacity is often limited by the flue gas flow.

A modern recovery boiler consists of heat transfer surfaces made of steel tube; furnace-1, superheaters-2, boiler generating bank-3 and economizers-4. The steam drum-5 design is of single-drum type. The air and black liquor are introduced through primary and secondary air ports-6, liquor guns-7 and tertiary air ports-8. The combustion residue, smelt exits through smelt spouts-9 to the dissolving tank-10.

The nominal furnace loading has increased during the last ten years and will continue to increase. Changes in air design have increased furnace temperatures.This has enabled a significant increase in hearth solids loading (HSL) with only a modest design increase in hearth heat release rate (HHRR). The average flue gas flow decreases as less water vapor is present. So the vertical flue gas velocities can be reduced even with increasing temperatures in lower furnace.

The most marked change has been the adoption of single drum construction. This change has been partly affected by the more reliable water quality control. The advantages of a single drum boiler compared to a bi drum are the improved safety and availability. Single drum boilers can be built to higher pressures and bigger capacities. Savings can be achieved with decreased erection time. There is less tube joints in the single drum construction so drums with improved startup curves can be built.

The construction of the vertical steam generating bank is similar to the vertical economizer, which based on experience is very easy to keep clean.Vertical flue gas flow path improves the cleanability with high dust loading.To minimize the risk for plugging and maximize the efficiency of cleaning both the generating bank and the economizers are arranged on generous side spacing. Plugging of a two drum boiler bank is often caused by the tight spacing between the tubes.

The spacing between superheater panels has increased. All superheaters are now wide spaced to minimize fouling. This arrangement, in combination with sweetwater attemperators, ensures maximum protection against corrosion. With wide spacing plugging of the superheaters becomes less likely, the deposit cleaning is easier and the sootblowing steam consumption is lower. Increased number of superheaters facilitates the control of superheater outlet steam temperature especially during start ups.

The lower loops of hottest superheaters can be made of austenitic material, with better corrosion resistance. The steam velocity in the hottest superheater tubes is high, decreasing the tube surface temperature. Low tube surface temperatures are essential to prevent superheater corrosion. A high steam side pressure loss over the hot superheaters ensures uniform steam flow in tube elements.
Future prospects
Recovery boilers have been the preferred mode of Kraft mill chemical recovery since the 1930s and the process has been improved considerably since the first generation. There have been attempts to replace the Tomlinson recovery boiler with recovery systems yielding higher efficiency. The most promising candidate appears to be gasification,where Chemrec's technology for entrained flow gasification of black liquor could prove to be a strong contender.

Even if new technology is able to compete with traditional recovery boiler technology the transition will most likely be gradual. First, manufacturers of recovery boilers such as Metso, Andritz andMitsubishi, can be expected to continue development of their products. Second, Tomlinson recovery boilers have a long life span, often around 40 years, and will probably not be replaced until the end of their economic lifetime, and may in the meantime be upgraded at intervals of 10 – 15 years.
see also previous article "Ncg (non condensible gases)"
May be useful.

NCG (NON CONDENSIBLE GASES)

noreply@blogger.com (Anonymous) — Thu, 5 Jul 2012 10:59:00 -0700

NCG Burning in Recovery Boilers This time i will explain about Non Condensible Gases or NCG in Power plant boiler.after yesterday I was talking about "How does a power plant boiler work?" NCG = Non Condensible Gases NCG are: the non-condensable gas, this gas has a very distinctive odor karesteristik. This odor is caused by a mixture of sulfur into TRS (Total Reduced Sulfur) Categories A.Composition and NCG NCG content include: Hydrogen sulfide (H2S) Mercaptan (CH3SH) Dimethyl sulfide (CH3) 2S Dimethyl disulfide (CH3) 2S2 Ethanol (C2H5OH) NCG gases are divided into two categories, namely: LVHC = Low Volume High Cocentration High Volume Low HVLC = Cocentration B. Sources of NCG NCG is the fuel in the RECOVERY BOILER sourced from: A. LVHC: a. Strippe gas b. Gas from the evaporator plan (VE) c. Faul VE Condensate Tank d. Digester plan (PULP MAKING) 2. HVLC: a. WBL Gas Tanks & Tank HBL 3 & VE b. Gas & PULP MAKING Design Data LVHC RB-1 Design Data Stripper Gas: Flow = 1550 Nm ³ / h Temp = 80 ° C Moisture = 48% Volume Gases from Evaporator Flow = 680 Nm ³ / h Temp = 50 ° C Moisture = 13% Volume Digester gas form Flow = 335 Nm ³ / h Temp = 90 ° C Moisture = 71%.see also previous article "Vacuum evaporator(VE)

Volume RB NCG SYSTEM (LVHC)

RB ODOROUS GAS ( HVLC)

Odorous Gas

1.NCG CONTENT

2.CONCENTRATION

Maybe useful.

COAL BOILER

noreply@blogger.com (Anonymous) — Tue, 12 Jun 2012 00:19:00 -0700

Classification of coal quality are generally divided into two, namely the division in this scientifically based pembatubaraaan level, and the division based on the intended use.Based on sequence pembatubaraannya, coal is divided into a young coal (brown coal or lignite), sub-bituminous, bituminous, and anthracite. While based on the intended use, divided into coal steam coal (steam coal), coal coke (coking coal or metallurgical coal), and anthracite.Steam coal is coal which use the most extensive scale.

Based on the method, be using steam coal consist of direct utilization of coal that meets certain specifications used immediately after going through the process of crushing (crushing / milling) as the first coal power plant, then use the first process to facilitate handling (handling) such as CWM (Coal Water Slurry), COM (Coal Oil Mixture), and CCS (Coal Cartridge System), and then pemanfataan through a conversion process such as gasification and liquefaction of coalIn the coal power plant, the fuel used is coal steam which consists of sub-bituminous and bituminous class. Lignite also started to get a place as a fuel in power plant lately, along with the development of technology that can accommodate the generation of low-quality coal.

Figure 1. Electric generation scheme on coal power plant

(Source: The Coal Resource, 2004)

At the power plant, coal is burned in the boiler produces heat which is used to change the water in the pipe that is passed in the boiler into steam, which then is used to drive turbines and generators rotate. Electricity generation in power plant performance is largely determined by the thermal efficiency in coal combustion process, because in addition to an effect on the efficiency of generation, can also lower the cost of generation. Then in terms of environment, it is known that the amount of CO2 emissions per unit of calories from coal is the highest when compared with other fossil fuels, with a comparison to coal, oil, and gas is 5:4:3. So based on trials that get the results that the increase in thermal efficiency by 1% will be able to reduce CO2 emissions by 2.5%, then the thermal efficiency will be improved significantly reduce the environmental burden caused by burning coal.Therefore, it can be said that the combustion technology (combustion technology) is a major theme in the effort to increase coal utilization efficiency is directly at the same time anticipating the future environmental issues.Basically the method of burning the plant is divided into three, namely the burning of a layer of fixed (fixed bed combustion), the burning of coal powder (pulverized coal combustion / PCC), and the burning of a floating layer (fluidized bed combustion / FBC). Figure 3 below shows the type - the type of boiler used for each - each combustion method.Figure 2. A typical boiler by combustion method(Source: Idemitsu Kosan Co.., Ltd.)Combustion Layer FixedCoating method still uses stoker boiler for combustion processes. As the fuel is coal with ash content that is not too low and the maximum size of about 30mm. In addition, because of the limitation of coal grain size distribution is used, it is necessary to reduce the amount of fine coal that come mixed into coal. The reason does not use coal with ash content is too low is because the method of this combustion, coal is burned on top of a thick ash layer formed on the lattice of fire (fire traveling grate) in stoker boilers. If levels of very little ash, ash layer will not be formed on the lattice so that combustion will occur directly on the lattice, which can cause severe damage in that section. Therefore, the ash content of coal is preferred for this type of boiler is about 10-15%. The minimum thick layer of ash that is needed for combustion is 5cm.Figure 3. Stoker Boiler(Source: Idemitsu Kosan Co.., Ltd.)In this stoker combustion, ash from burning of small amounts of fly ash, only about 30% of the total. Then with an effort such as the burning of two levels of NOx, NOx levels can be lowered to about 250-300 ppm. Meanwhile, to reduce SOx, still needed additional facilities such as flue gas desulfurization equipment.Combustion of Coal Powder (Pulverized Coal Combustion / PCC)Today, most especially the large-capacity power plant is still using the PCC method on the combustion of fuel. This is because the PCC system is a proven technology and has a high level of reliability. Efforts to improve plant performance is mainly done by increasing the temperature and pressure of the steam produced during the combustion process.Development starts from the sub-critical steam, then super-critical steam, steam and ultra super critical (USC). As an example of USC power plant which uses technology is generating no. 1 and 2 belong to J-Power in Tachibana Bay, Japan, which boilernya respectively - each with a capacity of 1050 MW Babcock made by Hitachi. The resulting vapor pressure is 25 MPa (254.93 kgf/cm2) and the temperature reached 600 ℃ / 610 ℃ (1 stage reheat cycles). The development of steam conditions and graph generation efficiency improvement at PCC is shown in figure 4 in below.Figure 4. The development of steam power plant conditions(Source: Clean Coal Technologies in Japan, 2005)At PCC, crushed coal by using coal PULVERIZER used (coal mill) up to a 200 mesh (74μm diameter), and then together - the same with the combustion air is sprayed into the boiler to be burned. Combustion method is sensitive to the quality of coal being used, especially the nature ketergerusan (grindability), slagging properties, properties fauling, and water content (moisture content). Coal is preferred for PCC boilers that have properties ketergerusan with HGI (Hardgrove Grindability Index) above 40 and the water content of less than 30%, and the ratio of fuel (fuel ratio) is less than 2. Combustion with the PCC method will produce ash which consists itself of clinker ash as much as 15% and the rest of the fly ash.Figure 5. PCC Boiler(Source: Idemitsu Kosan Co.., Ltd.)...

When done burning, nitrogen compounds present in coal will oxidize to form the so-called fuel NOx NOx, whereas nitrogen in the combustion air will oxidize to form NOx too high temperature is called thermal NOx. In total NOx emissions in flue gas, fuel NOx content reaches 80-90%. To overcome this NOx, denitrasi action (de-NOx) in the boiler during the combustion process takes place, by utilizing the properties of NOx reduction in coal.Figure 6. Denitrasi process in PCC boilers(Source: Coal Science Handbook, 2005)In the combustion process, the speed of injection of coal powder and air mixture into the boiler is reduced so that the ignition and combustion of fuel also slows. It can lower the combustion temperature, which resulted in decreased levels of thermal NOx.In addition, as shown in Figure 6 above, the fuel is not all feed into the main combustion zone, but some included in the section on the upper main burner. NOx is produced from primary pembakara subsequently burned through 2 levels. In the reduction zone which is a first-degree arson or arson is also called reduction (reducing combustion), nitrogen content in the fuel is converted to N2. Next, do a second degree burning or combustion oxidation (oxidizing combustion), the form of complete combustion in the combustion zone. With this action, NOx in exhaust gas can be compressed up to 150-200 ppm. As for the desulfurization still requires additional equipment ie flue gas desulfurization equipment.Floating layer combustion (Fluidized Bed Combustion / FBC)In the combustion method FBC, coal crushed first by using the maximum-sized crusher to 25mm. Unlike combustion using coal stoker who put on the lattice heat during combustion or spray PCC method of coal and air mixture during combustion, coal grains kept in a floating position, by passing a certain wind speed from the bottom of the boiler. The balance between the upward push of the wind and gravity will keep the grains of coal remain in the floating position so as to form a layer of a fluid is always moving. This condition will cause the fuel combustion is more perfect because of the position of coal is always changing so that air circulation can be run properly and sufficient for the combustion process.Due to the nature of such combustion, the fuel specification requirements that will be used for the FBC is not as restrictive as in other combustion methods. In general, there are no special restrictions for levels of fly substances (volatile matter), the ratio of fuel (fuel ratio) and ash content. In fact all kinds, including low rank coal can be burned with either though using the method of this FBC. Only when the coal will be incorporated into the boiler, the water content attached to the surface (free moisture) are expected to not more than 4%. In addition to the above advantages, the value added of the FBC method is a tool used coal crusher is not too complicated, and the size of the boiler can be reduced and made compact.When the combustion temperature in the PCC is around 1400 - 1500 ℃, then the FBC, the combustion temperature range between 850-900 ℃ course so that the levels of thermal NOx that arise can be suppressed. In addition, the mechanism of combustion of 2 levels as in the PCC, the total NOx levels can be reduced again.Then, when the desulfurization equipment is still required for the handling of SOx in combustion method fixed and PCC, then at FBC, desulfurization can occur simultaneously with the combustion process in boilers. This is done by mixing limestone (lime stone, CaCO3) and the coal then simultaneously inserted into the boiler. SOx produced during the combustion process, will react with lime to form gypsum (calcium sulfate). In addition to the desulfurization process, limestone also serves as a medium for the fluidized bed due to its software so that the pipe heater (heat exchanger tubes) is installed in the boiler is not easy to wear.Figure 7. A typical FBC boiler(Source: Coal Science Handbook, 2005)Based on the working mechanism of combustion, the method is divided into two namely Bubbling FBC FBC and circulating FBC (CFBC), as shown in Figure 7 above. It could be argued that the Bubbling FBC FBC is a basic principle, while the CFBC is development.In CFBC, there is another tool installed on a boiler is a high temperature cyclone. Fluidized bed of media particles that have not reacted and unburned coal which flew with the flow of exhaust gas will be separated in the cyclone is then channeled back to the boiler. Through this circulation process, fluidized bed height can be maintained, denitrasi process may take more optimal, and higher combustion efficiency can be achieved. Therefore, in addition to low-quality coal, materials such as biomass, sludge, plastics, and scrap tires can also be used as fuel in the CFBC. The ash residue almost entirely of fly ash with the flue gas flow, and will be arrested first by using the Electric Precipitator before the flue gas exit to the chimney (stack).Figure 8. CFBC Boiler(Source: Idemitsu Kosan Co.., Ltd.)At FBC, when the pressure inside the boiler the same as the outside air pressure, called the Atmospheric FBC (AFBC), whereas when the pressure is higher than the outside air pressure, about 1 MPa, called the pressurized FBC (PFBC).Combustion air pressure factors influence the development of this FBC technology. To Bubbling FBC develops from PFBC to Advanced PFBC (A-PFBC), while for CFBC thereafter developed into the Internal CFBC (ICFBC) and then pressurized ICFBC (PICFBC).PFBCIn PFBC, in addition to the heat generated is used to heat water into steam to turn a steam turbine, combustion gas is also produced which has a high pressure gas turbine that can play, so that using a PFBC power plant generation has a better efficiency compared to AFBC due to a combination of mechanisms (combined cycle) is. Gross value generation efficiency (gross efficiency) can reach 43%.In accordance with the principles of combustion in FBC, SOx produced at PFBC can be suppressed by the mechanism of desulfurization along with combustion in the boiler, while the NOx can be suppressed by combustion at relatively low temperatures (about 860 ℃) and the burning of 2 levels. Because the gases of combustion are used again by running into the gas turbine, the combustion ash that come flowing out along with the gas needs to be removed first. Use CTF (Ceramic Tube Filter) can effectively capture these ashes.Pressurized condition that produces a better combustion will automatically reduce levels of CO2 emissions so as to reduce the environmental burden.Figure 9. Working principle of PFBC(Source: Coal Note, 2001)To further improve thermal efficiency, gasification unit partially (partial gasifier), which uses gasification technology floating layer (fluidized bed gasification) was then added to the PFBC unit. With the combination of gasification technology is the effort to increase the temperature of the gas at the entrance (inlet) gas turbine allows it to be done.In the process of partial gasification in the gasifier, the carbon conversion is achieved is about 85%. This value can be increased to 100% through a combination with the oxidizing agent (oxidizer). Further development of PFBC is called the Advanced PFBC (A-PFBC), the working principle is shown in Figure 10 below. Efficiency of net generation (net efficiency) which produced the A-PFBC is very high, can reach 46%.Figure 10. The working principle of A-PFBC(Source: Coal Science Handbook, 2005)ICFBCSectional boilers ICFBC shown in figure 11 below.Figure 11. Sectional boilers ICFBC(Source: Coal Note, 2001)As shown in the figure, the main combustion chamber (primary combustion chamber) and the decision space heat (heat recovery chamber) separated by a barrier wall mounted sideways. Then, because the pipe heater (heat exchange tube) is not attached directly to the main combustion chamber, then no worries about wear and tear of the pipe so that the silica sand is used instead of limestone for FBC media. Limestone is still being used as a reducing agent, SOx, only the numbers pressed in accordance with the purposes only.At the bottom of the main combustion chamber windbox attached to the wind flow to the boiler, where the small-volume air flows through the middle to create the layer moves (moving bed) is weak, and large-volume air flow through both sides of the windbox is to create a strong layer moves. Thus, in the middle of the main combustion chamber will form a layer moves down slowly, while on both sides of the room, the media will be lifted FBC strong upward toward the center of the main combustion chamber and then come down slowly - land, and then raised again by the large volume of the windbox wind. This process will create a spiral flow (spiral flow) that occurs continuously in the main combustion chamber. The mechanism of spiral flow of media FBC can keep floating layer so that a uniform temperature. In addition, because the flow is moving at a very dynamic, the disposal of unburnt material is also easier.Then, when the media is a powerful FBC raised up at the top of the barrier wall, some will be turned toward the heat collection chamber. Because the space is also taking a hot air flow from the bottom, then the space will be formed layers move down slowly as well. As a result, the media FBC will flow from the main combustion chamber leading to the capture chamber heat and then back again into the main combustion chamber, forming a circulation flow (circulating flow) between the two spaces. Using a heating pipe installed in the room taking the heat, the heat from the primary combustion chamber flows through the mechanism of circulation taken earlier.In general, changes in the volume of air supplied to the heat collection chamber is directly proportional to the coefficient of thermal conductivity as a whole. Thus it is only by setting the volume of the wind, heat and temperature levels keterambilan on floating layer can be well controlled, so that the load settings can be done easily as well.To further improve the performance of the generation, the process on ICFBC then pressurized by entering the unit ICFBC into pressurized container (pressurized vessel), hereinafter referred to as pressurized ICFBC (PICFBC). With this mechanism in addition to water vapor, will be produced also a high-pressure combustion gases that can be used to rotate so that the generation of gas turbines in combination (combined cycle) can be realized.Generation Coal Gasification Combined WithIncreasing the efficiency of generation with a combination of mechanisms through the use of synthetic gas gasification process results as in A-PFBC, the next generation of technology lead to further intensify the use of coal gasification technology into the generation system. This effort eventually resulted in the generation system called the Integrated Coal Gasification Combined Cycle (IGCC).Since this paper only discusses the development of power generation technology, then an explanation of how the coal gasification process takes place will not be described here.IGCCAn outline flow chart IGCC power generation system is shown in figure 12Figure 12. Typical IGCC(Source: Clean Coal Technologies in Japan, 2005) below.As shown in the figure, there are tools on the gasification system (gasifier) used to produce gas, generally entrained flow type. Available on the market today for those types such as Chevron Texaco (now owned by GE Energy's license), E-Gas (formerly owned by Dow's license, then Destec, and last Conoco Phillips), and Shell. The working principle is the same all three devices, namely coal and high levels of oxygen incorporated into it and then performed the reaction of partial oxidation (partial oxidation) to produce synthetic gas (syngas), which is composed of over 85% of H2 and CO. Because the reaction takes place at high temperatures, ash in coal will melt and form a slag in a molten state (glassy slag). The heat generated by the gasification process can be used to generate high pressure steam, which then flowed into the steam turbine.Oxygen is used for the gasification process generated from the facility Air Separation Unit (ASU). This unit serves to separate the oxygen from the air through cryogenic separation mechanism, producing a yield of about 95% oxygen. In addition to oxygen, the ASU also produced nitrogen used as inert media for feeding coal into the gasifier, but can also be used to lower the temperature of the combustor so that NOx emissions can be controlled.In the synthesis gas, in addition to H2 and CO is also produced other elements that are not environmentally friendly such as HCN, H2S, NH3, COS, mercury vapor, and char.Therefore, the gas must be processed first to remove the part before it is sent to the gas turbine. Flue gas from the gas turbine and then flows to the Heat Recovery Steam Generator (HRSG) which serves to change the heat of the gas into water vapor, which then flowed into the steam turbine. With this mechanism, the efficiency of the resulting net generation is also far exceeds the generation of the regular system (PCC) that currently dominate. In addition to the generation efficiency, another advantage IGCC is very low emission levels of pollutants generated, fuel flexibility that can be used, water usage is 30-40% lower than conventional power plant (PCC), a significant level of CO2 capture, slag can be utilized to construction materials, and others - others.An example is the Nuon IGCC located in Buggenum, the Netherlands, with a capacity of 250mW. The plant produces a net efficiency of 43% (Low Heating Value), with the performance of environmental quality standards are very good. NOx emissions are produced very low at less than 10 ppm, then the sulfur removal efficiency above 99%, the level of flyash emissions, chloride compounds and volatile heavy metals that can be practically zero, and the waste water can be recirculated back so that no waste water disposal into the environment.In addition to these advantages, there are also weaknesses in the IGCC system developed at this time, for example, the amount of generation capacity is determined based on the number of units and gas turbine model to be used. Examples for GE Frame 7FA gas turbines with a capacity of 275MW. If IGCC will be operated with a generating capacity of 275MW, is quite a unit that is installed. When the second unit to be used, means the generation capacity to 550MW, and if 3 units it will be 825MW. Then when the desired generation capacity is under 200MW, then the model used is no longer the GE Frame 7FA, but GE 7FA with a capacity of 197MW. Similarly, if the generation capacity requires a smaller, then the GE 6FA a capacity of 85MW can be used.With the combination of model and number of gas turbine units to be used this, but will limit the generation capacity in the IGCC, is actually also will narrow the operating range. For example when going to lower the load at peak operation, it should be done by reducing the load on the gas turbine. Decrease the burden of this gas turbine will automatically lower the efficiency of generation and the consequences are less well on emissions of pollutants generated. Another weakness that need to be observed from the IGCC system today is the generation cost per kW and operation & maintenance (O & M) are more expensive, as well as the availability factor (AF) is lower than the PCC.IGCC history began in 1970 when the company STEAG of West Germany the expandable capacity of 170MW IGCC. Much later, demonstration project called Cool Water IGCC plant was launched in the U.S. in 1984, which operates a 120MW IGCC capacity until 1989. As of this writing, there is actually not a purely commercial IGCC units. The main cause is a large construction investments, as well as IGCC technology that has not been proven. IGCC technology here means the circuit of the entire building process (building blocks) that form the IGCC system intact. This needs to be emphasized because of their technology - for example, each unit in IGCC gasifier, HRSG, gas turbines, steam turbines, and the other is a proven technology. During the development of which lasted about 20 years since the Cool Water project, IGCC units are in commercial operation today both in the U.S. and in Europe in the first demonstration plant status. Examples of some of the IGCC plant is1. Tampa Electric Polk Power Station IGCC 250mW, located in Florida, USA. IGCC is operating since September 1996 under the Tampa project, using a gasifier of Chevron Texaco (now GE Energy). The fuel used is coal and petroleum coke (petcoke). The problem faced is more low carbon conversion rate compared with the planned value.Fauling had also occurred in the gas cooler.2. 260MW IGCC Wabash River Power Station, located in Indiana, USA. Operation since September 1995 under the Wabash River project, this plant uses gasification technology from Global Energy (now part of Conoco Phillips). Since the end of the project from the U.S. Department of Energy (DOE) in 2001, the fuel used is 100% petcoke.3. 250mW Nuon IGCC Power Station, located in Buggenum, Netherlands. This stems from IGCC Demkolec project that began in January 1994. The technology used is from Shell, the fuel is coal mixed with biomass (sludge and waste wood) to further reduce CO2 emissions. The problem that ever happened was a gas leak, the onset of cooler and cooler fauling on gas when mixed sludge of about 4-5%....

Figure 13. Nuon IGCC, Buggenum(Source: Thomas Chhoa, Shell Gas & Power, 2005)4. Elcogas 300MW IGCC Power Station, located in Puertollano, Spain. IGCC plant is in operation since June 1996 under the project Puertollano, using gasification technology from Prenflow (currently part of Shell). Fuel is a mixture of petcoke and coal ash 40% yield with a ratio of 50:50. Under the program of the European Union, this plant is planned as a place for the project taking CO2 (CO2 recovery) and H2 production.Taking into account various factors, including the generation of high efficiency, environmentally friendly factor, and a proven gasification technology, an effort to further reduce the weaknesses of IGCC have been started.Apart from cost, effort has also been conducted to further improve the efficiency of generation, namely by adding a fuel cell (fuel cell) into the IGCC system. Thus, there will be three types of combinations of generation in this new system of gas turbines, steam turbines, and fuel cell. Generation method is called with Integrated Coal Gasification Fuel Cell Combined Cycle (IGFC), the diagram shown in figure 16 alirnya below.Figure 14. Typical IGFC(Source: Clean Coal Technologies in Japan, 2005)In fuel cells, electricity generation is done directly through an electrochemical reaction between hydrogen and oxygen so that the energy loss rate and efficiency pembangkitannya little high. Hydrogen can be derived from natural gas, bio gas, or gases of coal gasification. Based on the material used for the electrolyte, the fuel cell is divided into 4-Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (MCFC), Solid-Oxide Fuel Cell (SOFC) and Proton-Exchange Membrane Fuel Cell (PEFC). Below is shown the characteristics of the four types of fuel cells.Table 1. Characteristics of Fuel Cells(Source: Clean Coal Technologies in Japan, 2005)From the table above shows that fuel cells are suitable for combination with the generation of gas turbines is the SOFC, because the reaction produces very high temperatures.Compared with the PCC, the generation with IGFC method is theoretically capable of reducing CO2 emissions by 30%. Another plus is the high efficiency of the generation that can be achieved is at least 55%. Besides these advantages, there are several things to consider before IGFC really - really can be applied commercially. The first is the urgency of IGCC technology maturation, because IGFC basically is the development of IGCC. Then, the need for fuel cell development but low-cost high-efficiency, to support the generation cost competitive in the future.CoverDevelopments in power plant coal combustion technology has been presented above. In general it can be said that a growing technology does not depart from the principal so-called 3E, namely Engineering (technical side), Economy (the economy), and the Environment (the environment). In the early stages, Economy factor may be the primary consideration for the construction of generation facilities, followed by Engineering, and the last Environment. But along with efforts to reduce pollution or environmental contamination that caused the tightness of environmental quality standards, it appears that the order of 3E is starting to change. Environment factors are slowly ranks first in the consideration of technology development, and engineering, and last precisely Economy.Taking the example of IGCC, it is natural that the early stage of development would require a large fee. But along with the strengthening of environmental issues and the technology matures, it will decrease the cost and at a certain time would be competitive against existing technologies. Instead, the existing generation technologies, for example, which currently dominates the PCC, gradually will be more expensive to accommodate the environmental quality standards are increasingly stringent, and in the end it actually would cost in terms of economics. Showing below the generation cost comparison between IGCC and PCC in the U.S. over the last 20 years, and predictions in the future.Figure 15. Generation Cost Comparison IGCC and PCC per kW in the U.S.(Source: JCOAL Journal, vol.3, January 2006)From the chart above shows that over the last 20 years, the cost of generation for the PCC increased by about 50%. This increase is caused by the addition of equipment to reduce the environmental burden, such as facilities desulfurization (FGD). In contrast, the generation cost per kW at IGCC actually decline, and expected in 2010, its value will be equal to the PCC, which is about $ 1200.Reference1. Amick, Phil, Flexibility Coal Gasification for Fuels & Products, ConocoPhillips, 20052. Baardson, John A., Coal to liquids: Shell Coal Gasification with Fischer-Tropsch Synthesis, Baardson Energy LLC, 2003.3. Chhoa, Thomas, Shell Gasification Business in Action, Shell Gas & Power, 2005.4. JCOAL, Coal Science Handbook, the Japan Coal Energy Center, 2005.5. JCOAL, JCOAL Journal Vol. 2, nov. 2005, the Japan Coal Energy Center, 2005.6. JCOAL, JCOAL Journal Vol. 3, January 2006, the Japan Coal Energy Center, 2006.7. JCOAL, JCOAL Journal Vol. 4, mar. 2006, the Japan Coal Energy Center, 2006.8. Presentation Materials, Idemitsu Kosan Co.., Ltd., 2003.9. Sekitan no Kiso Chishiki, Sekitan Shigen Kaihatsu Kabushiki Kaisha.10. Shigen Enerugi Shigen Nenryou Bu-Chou, Ko-to-ru No. 2001 Nen Ban, Shigen Sangyou Shinbunsha, 2001.11. Sema, Tohru, Karyoku Hatsuden Souron, Denki Gakkai, 2002.12. WCI, The Coal Resource, World Coal Institute, 2004.

see also previous article "Chemical recovery boiler"

CHEMICAL RECOVERY BOILER

noreply@blogger.com (Anonymous) — Mon, 28 May 2012 03:19:00 -0700

HEART OF A CHEMICAL PULP MILL

The recovery boiler plays a central role in the chemical cycle of a modern pulp mill. The boiler produces energy for the mill.

The spent liquor from the digesting plant goes first to the evaporation plant where the dry solids content of the liquor is increased. Then the evaporated liquor comes to the recovery boiler plant. Fly ash from electrostatic precipitators is mixed into the black liquor. After additional concentration of the black liquor in the evaporation plant the liquor is burned in the combustion chamber of the boiler.

Feed water is pumped first to the economizers where it is preheated by flue gas. The water then enters the water circulation system of the boiler. During combustion of the black liquor high pressure steam is generated in the boiler. The superheated steam flows from boiler to a turbine generator plant.

The hot smelt flow of the regenerated chemicals is drained from the furnace floor to the dissolving tank. The chemicals are dissolved into weak white liquor and returned to a recausticizing plant for further processing.

EXPERIENCE

Manufacturing of steam boilers started in Varkaus, Finland, in 1872. The first boilers were used in vessels. The first recovery boiler was manufactured in 1952 for Lohja-Kotka Oy, Finland. The steam pressure was 45 bar and steam temperature 400 C. The dry solids combustion capacity of the boiler was 110 tons per day. The combustion capacity of modern recovery boilers is about 30 times higher.see also previous article "Furnace camera"

May be useful.

RECOVERY BOILER WORK SYSTEM

noreply@blogger.com (Anonymous) — Mon, 7 May 2012 22:27:00 -0700