Chemical Engineering Techs

GATE Chemical Engineering Questions and Answers – Chemical Reaction Engineering

2022-10-11T17:51:00.004+05:30

Common data for the following two questions

The following gas phase reaction are carried out isothermally in a CSTR

A→2R; r₁ = k₁P_A; k₁ = 20 mol/(s-m³-bar)

A→3R; r₂ = k₂P_A; k₂ = 40 mol/(s-m³-bar)

Total pressure = 1 bar, F_A0 = 1 mol/s; feed is pure A

The volume of CSTR required for a fractional conversion equal to 0.3 due to the first reaction is

(A) 0.011

(B) 0.021

(D) 0.375

GATE 2003

Answer: (B)

What is the maximum possible value of F_R (mol/s)?

(A) 1/3

(B) ½

(D) 2

GATE 2003

Answer: (C)

A liquid phase reaction is to be carried out under isothermal. The reaction rate a function of conversion has been determined experimentally and is shown in Figure given below. What choice of reactor or combination of reactors will require the minimum overall reactor volume, if a conversion of 0.9 is desired?

(A) CSTR followed by a PFR

(B) PFR followed by a CSTR

(D) PFR followed by a CSTR followed by a PFR

GATE 2003

Answer: (D)

A CSTR is to be designed in which an exothermic liquid phase first order reaction of the type A→R is taking place. The reactor is to be provided with a jacket in which coolant is flowing.

Following data is given

C_A0 = 5 kmol/m³, X_A = 0.5

Feed temperature = reactor temperature = 40⁰C, rate constant at 40⁰C = 1 min^-1 (ΔH) = -40 KJ/mol, ρ = 1000 kg/m³, C_P = 4 J/g⁰C, q = 10^-3 m³/min (ρ and C_P are same for the reactant and product streams). The amount of heat to be removed is

(A) 2/3 kW

(B) 1 kW

(D) 4 kW

GATE 2003

Answer: (C)

An exothermic reaction takes place in an adiabatic reactor. The product temperature ____________ the reactor feed temperature.

(A) Is always equal to

(B) Is always greater than

(D) May be greater or less than

GATE 2002

Answer: (B)

The extent of a reaction is

(A) Different for reactants and products

(B) Dimensionless

(D) All of the above

GATE 2002

Answer: (A)

For an ideal plug flow reactor the value of the Peclet number is

(A) Zero

(B) Infinity

(D) 10

GATE 2002

Answer: (B)

In the hydro dealkylation of toluene to benzene, the following reaction occur

C₇H₈ + H₂ → C₆H₆ + CH₄

2C₆H₆ → C₁₂H₁₀ + H₂

Toluene and hydrogen are fed to a reactor in a molar ratio 1:5. 80% of the toluene gets converted and the selectivity of benzene (defined as moles of benzene formed/per moles of toluene converted) is 90%. The fractional conversion of hydrogen is

(A) 0.16

(B) 0.144

(D) 0.136

GATE 2002

Answer: (C)

A batch adiabatic reactor at an initial temperature 373 K is being used for the reaction A → B.

Assume the heat of reaction is -1 kJ/mol at 373 K and the heat capacity of both A and B to be constant and equal to 50 J/mol-K. The temperature rise after a conversion of 0.5 will be

(A) 5⁰C

(B) 10⁰C

(D) 100⁰C

GATE 2002

Answer: (B)

A pulse tracer is introduced in an ideal CSTR (with mean residence time τ) a time t = 0. The time taken for the exit concentration of the tracer to reach half of its initial value will be

(A) 2τ

(B) 0.5τ

(D) 0.693τ

GATE 2002

Answer: (D)

The reaction rate constant at two different temperatures T₁ and T₂ are related by

GATE 2001

Answer: (B)

The conversion for a second order irreversible reaction (constant volume)

in batch mode is given by

GATE 2001

Answer: (B)

The first order gas phase reaction

is conducted isothermally in batch mode. The rate of change of conversion with time is given by

GATE 2001

Answer: (C)

The reaction A → B is conducted in an isothermal batch reactor. If the conversion of A increases linearly with holding time, then the order of the reaction is

(A) 0

(B) 1

(D) 2

GATE 2000

Answer: (A)

The conversion for a first order liquid phase reaction A → B in a CSTR is 50%. If another CSTR of the same volume is connected in series, then the % conversion at the exit of second reactor will be

(A) 60

(B) 75

(D) 100

GATE 2000

Answer: (B)

The following half life data are available for the irreversible liquid phase reaction A → products.

Initial conc. (kmol/m³) Half life (min)

2 2

8 1

The overall order of the reaction is

(A) 0.5

(B) 1

(D) 2

GATE 2000

Answer: (C)

In solid catalyzed reactions the diffusional effects are more likely to affect the overall rate of reaction for

(A) Fast reactions in catalysts of small pore diameter

(B) Fast reactions in catalysts of large pore diameter

(D) Slow reactions in catalyst of large pore diameter

GATE 2000

Answer: (D)

The experimentally determined overall order for the reaction

A + B → C + D is two. Then the

(A) Reaction is elementary with a molecularity of 2

(B) Molecularity of the reaction is 2, but the reaction may not be elementary

(D) Reaction is elementary but the molecularity may not be 2

GATE 2000

Answer: (B)

For liquid phase parallel reaction

The desired product is R. A higher selectivity of R will be achieved if the reaction is conducted at

(A) Low temperature in a CSTR

(B) High temperature in a CSTR

(D) High temperature in a PFR

GATE 2000

Answer: (A)

The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m³ is fed to the reactor at the rate of 0.01 m³/s and at a temperature of 500 K. If the exit conversion is 20%, then the exit temperature (in K) is

Data: heat of reaction at 298 K = -50,000 KJ/kmol of A rejected

Heat capacities C_P,A = C_P,B = 100 KJ/kmol.K (may be assumed independent of temperature).

(A) 400

(B) 500

(D) 1000

GATE 2000

Answer: (C)

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Conference/Seminar/Workshop/FDP/STTP/Certificate Course/Special Lecture

2022-07-20T16:45:00.009+05:30

Event: Summer School on Nanomaterials: Concepts and Application

Type of Event: Summer School

Date: 21.08.2022 – 27.08.2022

Organized by: Centre for Research in Nanoscience and Nanotechnology (CRNN) University of Calcutta, West Bengal, India

Themes: fundamental aspects of Nanoscience and Nanotechnology, covering the areas of Physical, Chemical, Biological, and Engineering Sciences. Both basic concepts and applications will be covered.

Application Submission Deadline: 12.08.2022

Registration Deadline: 18.08.2022

Confirmation Deadline: 16.08.2022

Registration Fee: Faculty Member/Scientist/ Post-doctoral Fellow: INR 8000 Research Scholar/Student/ Technical Staff: INR 5000

For Details Click on: Brochure

Event: Training Program on R&D Equipment

Type of Event: Training Program

Date: 28.07.2022 – 03.08.2022

Organized by: Pt. Ravishankar Shukla University, Raipur (Spoke), NIT Warangal (Hub).

Themes: To gain knowledge about the in-depth analysis of the characterization techniques using high-end analytical instruments such as TD-GC-MS-ECD-FID, AAS, XRD, HPLC, NMR, Ion-Chromatography

Eligibility: Persons of Indian origin. Faculty/Scientists/Post-Doc Fellows / Ph.D.

Fellows / Industry Persons / M.Sc. students/ MTech.

Students who are actively involved in research and development (R&D) in the fields of Chemistry, Physics, Instrumentation, or any relevant area.

Not more than 3 participants from one institution per training program will be allowed

Date of Notification of Acceptance: The shortlisted candidates will be intimated through mail.

Registration Fee: No Registration Fee

For Details Click on: Brochure

Event: Circular Economy and Resource Recovery for Sustainability

Type of Event: Course

Date: 25.07.2022 – 29.07.2022

Organized by: Department of Chemical Engineering, National Institute of Technology WARANGAL, India.

Themes: Circular Economy in wastewater infrastructure: Introduction, Approaches, Water-Economy Nexus. Policy frameworks affecting circular economy approaches to wastewater treatment and resource (water, energy, nutrients) recovery. Resource recovery: Methods and limitations of water recovery for potable and non-potable applications. Resource recovery: Methods and limitations of nutrient recovery. Sludge treatment to minimize environmental impact. Intersections of water-energy-nutrient recovery and conflicts/synergies. Sludge treatment to recovery resources. Novel value chain configurations for product recovery from sludge. Wastewater treatment plant as a water resource recovery facility – conceptual modeling and simulations. Circular economy action plans to develop water-economy nexus. Sustainable water management in SMART Cities of the Future.

Registration Fee: Industry/ Research Organizations: Rs. 5,000/-

Faculty: Rs. 2,000/-

Students & Research Scholars: Without award of Grade: Rs. 1,000/-

With award of Grade: Rs. 1,500/-

Faculty/Scientists/Industry Participants from abroad: US $400

For Details Click on: Brochure

Event: Internship program on “Thermal Management of Thermoelectric Coolers for High-Performance Cooling Applications”

Type of Event: Internship Program

Date: 25.07.2022 – 25.08.2022

Organized by: Department of Mechanical Engineering, National Institute of Technology, Hamirpur, India

Themes: Thermal management system, Advancement of heat transfer augmentation for various fields and its techniques, Fabrication of thermal management system and Ansys Fluent Simulation of fluid flow.

Eligibility: M.Tech in Thermal or equivalent discipline form University/Institution/College

Registration Fee: No fee for this internship program

For Details Click on: Brochure

Event: International Conference On Advanced Functional Materials: Future Perspectives (AFMFP-2022)

Type of Event: International Conference

Date: 06.08.2022-08.08.2022

Organized by: Dr. B. R. Ambedkar National Institute of Technology Jalandhar, India

Themes: Polymers and Composites, Sensors and Actuators, Nanomaterials, Materials for Healthcare, Electronic Materials, Forensic Materials, Smart Textiles, Defense Materials, Energy Materials, Stimuli Responsive Materials, Materials for Catalysis, Materials for Environment, Materials for Manufacturing.

Registration Fee: Participant Indian (INR) Foreign (USD)

Industrial 5000 200

Faculty/Scientist 2000 100

Student 1000 80

For Details Click on: Brochure

Event: Online Workshop on “Intellectual Property Rights (IPR) & Patents and Design filing

Type of Event: Workshop

Mode: Online

Date: 26.07.2022 (2.30 P.M – 3.30 P.M.)

Organized by: National Institute of Technology Tiruchirappalli In association with Rajiv Gandhi National Institute of Intellectual Property Management (RGNIIPM) Government of India, Nagpur, India.

Registration Deadline: No fees

Registration Fee: No fees

For Details Click on: Brochure

Event: Short Term Course on Flow Visualisation and Measurement Techniques in the Incompressible and Compressible Flows

Type of Event: Short Term Course

Date: 1.08.2022 – 5.08.2022

Organized by: Department of Aerospace Engineering, Indian Institute of Technology Kharagpur, India.

Themes: 1. Introduction to Flow Visualisations and Measurements 2. Smoke and Dye Visualisations 3. PIV Measurements 4. Hotwire Anemometry Measurements 5. LDV Measurements 6. Schlieren Flow Visualisations 7. Temperature Measurements 8. Concluding Remarks

Last Date for receiving the application form with the Registration Fee : 28/ 07/ 2022

Intimation to the participants : 28/ 07/ 2022

Start of the Course : 01/ 08/ 2022

End of the Course : 05/ 08/ 2022

Registration Fee: Industry Participants = Rs. 12,000/-

Faculty from Colleges = Rs. 6,000/-

Students of IIT Kharagpur = Rs. 1,000/-

Students from other Institutions = Rs. 2,500/-

No fees for faculty from IIT Kharagpur.

GST 18% is included in the course fee.

For Details Click on: Brochure

Event: International Conference on Modeling, Analysis and Simulations of Multiscale Transport Phenomena (ICMASMTP - 2022)

Mode: Hybrid Mode

Type of Event: International Conference

Date: 25.08.2022-27.08.2022

Organized by: Department of Mathematics, IIT Kharagpur, India

Themes: Transport in Porous networks, Evolution Equations and Their Existence Theories, Homogenization Theory, Numerical Techniques and Simulations for Transport Processes, Free Boundary Problem, Multiscale modeling of electrokinetic transport, Computational Linear Algebra, Numerical Mathematics for Non-linear Systems, Micro- and Nano-fluidics Modeling, Theoretical and Computational Fluid Dynamics, Computational Biology, Machine learning approach.

Last date of Registration: July 31st, 2022

Registration Fee: For Online mode: Rs. 0 (registration is mandatory)

For Offline mode: Rs. 3000 (PhD students),

Rs. 5000 (Postdocs),

Rs. 10,000 (Faculties and industry participants)

For Details Click on: Brochure

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-22T16:57:00.006+05:30

SO₂ from air is absorbed by pure water in a counter current packed column operating at constant pressure. The compositions and the flow rates of the streams are shown in the figure.

In addition, use the following data and assumptions

· Column operates under isothermal conditions

· At the operating temperature of the column, y^* = 40x, where y^* is the mole fraction of SO₂ in the gas that is in equilibrium with water containing SO₂ at a mole fraction of x

· Solution is dilute and the operating line is linear

· Negligible amount of water evaporates

The number of transfer units (NTU) for this column is

(A) 0.5

(B) 1.0

(D) 2.0

GATE 2020

Answer: (D)

Ratio of momentum diffusivity to thermal diffusivity is

(A) Reynolds number

(B) Prandtl number

(D) Peclet number

GATE 2020

Answer: (D)

Two film theory applies for absorption of a solute from a gas mixture into a liquid solvent. The interfacial mass transfer coefficient (in mol m-2 s-1) for the gas side is 0.1 and for the liquid side is 3. The equilibrium relationship is y* = 2x, where x and y* are mole fractions of the solute in the liquid and gas phases, respectively. The ratio of the mass transfer resistance in the liquid film to the overall resistance is

(A) 0.0161

(B) 0.0322

(D) 0.0645

GATE 2020

Answer: (C)

Consider the equilibrium data for methanol-water system at 1 bar given in the figure below.

A distillation column operating at 1.0 bar is required to produce 92 mol% methanol. The feed is a saturated liquid. It is an equimolar mixture of methanol and water. The minimum reflux ratio is

(A) 0.33

(B) 0.50

(D) 1.17

GATE 2020

Answer: (B)

Two ideal cross-current stages operate to extract P from a feed containing P and Q, as shown below.

The mass flow rates of P and Q fed to Stage 1 are 1000 kg h^-1 and 10,000 kg h^-1, respectively. Pure solvent (S) is injected at mass flow rate of 5000 kg h^-1 and 15000 kg h^-1 to Stages 1 and 2, respectively. The components Q and S are immiscible. The equilibrium relation is given by Y^* = 1.5X, where X is the mass of P per unit mass of Q in the raffinate, and Y^* is mass of P per unit mass of S in the extract, which is in equilibrium with the raffinate. The mass flow rate of P (in kg h^-1) in the raffinate from Stage 2 is ________ (round off to nearest integer).

GATE 2020

Answer: 176

Consider a vertically falling film of water over an impermeable wall. The film is in contact with a static pool of non-reactive pure gas. The gas diffuses into the water film over the entire height of the falling film. The height of the film is m, and its thickness is m. The velocity of water, averaged over the film thickness, is 0.01 m s^-1. The gas concentration (in kg m^-3), averaged over the film thickness is

Where y is the vertical position in meters measured from the top of the wall.

In addition, use the following data and assumptions

o The flow is fully developed

o The width of the film is much larger than the thickness of the film, and the dissolved gas concentration is invariant over this width

o The solubility of the gas in water, C_Ai, is constant

o Pure water enters at y = 0

o The evaporation of water in negligible

The mass transfer coefficient on the liquid side (in mm s^-1), averaged over the entire height of the falling film is _______ (round off to 3 decimal places).

GATE 2020

Answer: 0.03

The correct expression for the Colburn j-factor for mass transfer that relates Sherwood number (Sh), Reynolds number (Re) and Schmidt number (Sc) is

GATE 2019

Answer: (A)

Three distillation schemes for separating an equimolar, constant relative volatility ABC mixture into nearly pure components are shown. The usual simplifying assumptions such as constant molal overflow, negligible heat loss, ideal trays are valid. All the schemes are designed for minimum total reboiler duty. Given that the relative volatilities are in the ratio α_A:α_B:α_C ≡ 8:2:1, the correct option that arranges the optimally-designed schemes in ascending order of total reboiler duty is

(A) I, II, III

(B) III, I, II

(D) III, II, I

GATE 2019

Answer: (B)

In the drying of non-dissolving solids at constant drying conditions, the internal movement of moisture in the solid has a dominant effect on the drying rate during

(A) The initial adjustment period only

(B) The constant rate period only

(D) Both the initial adjustment and constant rate periods

GATE 2019

Answer: (C)

A binary mixture with components A and B is to be separated in a distillation column to obtain 95 mol% A as the top product. The binary mixture has a constant relative volatility α_AB = 2. The column feed is a saturated liquid containing 50 mol% A. Under the usual simplifying assumptions such as constant molal overflow, negligible heat loss, ideal trays, the minimum reflux ratio for this separation is____________________ (rounded off to one decimal place). GATE 2019

Answer: 1.7

A countercurrent absorption tower is designed to remove 95% of component A from an incoming binary gas mixture using pure solvent B. The mole ratio of A in the inlet gas is 0.02. The carrier gas flow rate is 50 kmol/h. The equilibrium relation is given by Y = 2X, where Y and X are the mole ratios of A in the gas and liquid phases, respectively. If the tower is operated at twice the minimum solvent flow rate, the mole ratio of A in the exit liquid stream is________________(rounded off to three decimal places).

GATE 2019

Answer: 0.005

100 kg of a feed containing 50 wt. % of a solute C is contacted with 80 kg of a solvent containing 0.5 wt.% of C in a mixer-settler unit. From this operation, the resultant extract and raffinate phases contain 40 wt.% and 20 wt.% of C, respectively. If E and R denote the mass of the extract and raffinate phases, respectively, the ratio E/R is

(A) ¼

(B) ½

(D) 1

GATE 2019

Answer: (C)

Two spherical camphor particles of radii 20 cm and 5 cm, far away from each other, are undergoing sublimation in a stream of air. The mass transfer coefficient is proportional to

Where, r(t) is the radius of the sphere at time t. Assume that the partial pressure of camphor far away from the surface of the particle is zero. Also, assume quasi-steady state, identical ambient conditions, and negligible heat effects. If t₁ and t₂ are the times required for complete sublimation of the 20 cm and 5 cm camphor particles, respectively, the ratio t₁/t₂ is _________ (rounded off to one decimal place).

GATE 2019

Answer: 8

Two packed towers are designed for the same mass velocity of the gas. The first has liquid and gas flow rates of 30 kg/s and 1.2 kg/s, respectively, while the corresponding flow rates in the second tower are 67.5 kg/s and 1.8 kg/s. The ratio of the design diameter of the wider tower to that of the narrower tower is

(A) 2

(B) 1.8

(D) 1.225

GATE 2018

Answer: (D)

According to the surface renewal theory, the unit of fractional rate of surface renewal is

(A) m² s^-2

(B) m² s^-1

(D) s^-1

GATE 2018

Answer: (D)

For absorption of H₂S from a mixture with hydrocarbon vapour into an aqueous alkanolamine solution, the liquid phase mass transfer resistance is

(A) Significantly higher than that of the gas phase

(B) Negligible compared to that of the gas phase

(D) Dependent on the gas phase mass transfer resistance

GATE 2018

Answer: (B)

Pitot tube is used to measure

(A) Liquid level in a tank

(B) Flow velocity at a point

(D) Vorticity

GATE 2018

Answer: (B)

The humidity of air at a dry-bulb temperature of 65°C is 0.025 kg water/kg dry air. The latent heat of vaporization of water at 0°C is 2500 KJ/kg. The psychometric ratio of air is 0.95 KJ (kg dry air)-1 K-1. Considering 0°C as reference temperature, the enthalpy of air (in KJ/kg) at its adiabatic saturation temperature of 35°C is _________ (rounded off to two decimal places).

GATE 2018

Answer: 124

It is decided to extract A from a feed containing 20 mol% A and 80 mol% B in two ideal cross-current stages as shown below, using equal amount of pure solvent C in each stage.

Components B and C are immiscible. 60% of A in the feed is extracted in stage 1. The equilibrium relation is given by Y^* = 1.5 X wher,

X = moles of A per mole of B in raffinate

Y^* = moles of A per mole of C in extract in equilibrium with raffinate

The mol % of A in raffinate from stage 2 is ____________ (rounded off to second decimal place).

GATE 2018

Answer: 3.85

A binary distillation column is designated by McCabe-Thiele method to get a distillate mole fraction of 0.9. The enriching section operating line has an intercept with y-axis at 0.3 mole fraction. The ratio of liquid to vapour molar flow rate in the enriching section is _______ (rounded off to third decimal place).

GATE 2018

Answer: 0.667

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Related Article:

GATE Chemical Engineering Questions and Answers – Chemical Reaction Engineering

GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-21T16:42:00.001+05:30

A fiberboard sheet (1.5 m × 2.0 m × 15 mm) is being dried by suspending it horizontally in a current of hot, dry air. The edges are insulated so that drying takes place only from the top and bottom surfaces. The wet sheet weighing 16 kg with initial moisture content of 60% loses moisture at a constant rate of 1.25 × 10^-5 kg m^-2 s^-1 until the moisture content falls to 30%. All moisture contents are on dry basis. The time required for drying during constant rate period (in hour) is _________________ (rounded off to third decimal place).

GATE 2018

Answer: 11.11

The composition of vapour entering a tray in a distillation column is 0.47. The average composition of the vapour leaving the tray is 0.53. The equilibrium composition of the vapour corresponding to the liquid leaving this tray is 0.52. All the compositions are expressed in mole fraction of the more volatile component.

The Murphree efficiency based on the vapour phase, rounded to the nearest integer, is ______ %.

GATE 2017

Answer: 120

Which of the following conditions are valid at the plait point?

P) Density difference between the extract and raffinate phases is zero

Q) Interfacial tension between the extract and raffinate phases is zero

R) Composition difference between the extract and raffinate phases is zero

(A) P and Q only

(B) Q and R only

(D) P, Q and R

GATE 2017

Answer: (D)

In a batch adsorption process, 5 g of fresh adsorbent is used to treat liter of an aqueous phenol solution. The initial phenol concentration is 100 mg/liter. The equilibrium relation is given by

q^* = 1.3C

Where, q* is the amount of phenol adsorbed In mg of phenol per gram of adsorbent and C is the concentration of phenol in mg/liter in the aqueous solution.

When equilibrium is attained between the adsorbent and the solution, the concentration of phenol in the solution, rounded to 1 decimal place, is _____________ mg/liter.

GATE 2017

Answer: 13.33

Consider steady state mass transfer of a solute A from a gas phase to a liquid phase. The gas phase bulk and interface mole fractions are y_A,G and y_A,i, respectively. The liquid phase bulk and interface mole fractions are x_A,L and x_A,i, respectively. The ratio (x_A,i – x_A,L)/(y_A,G – y_A,i) is very close to zero.

This implies that mass transfer resistance is

(A) Negligible in the gas phase only

(B) Negligible in the liquid phase only

(D) Considerable in both the phases

GATE 2017

Answer: (B)

The vapour phase composition and relative volatilities (with respect to n-propane) on an ideal tray of a distillation column are

Component	Methane	Ethane	n-Propane
Mole fraction in vapour	0.12	0.28	0.60
Relative volatility	10	4	1

The mole fraction of n-propane in the liquid phase, rounded to 2 decimal places, is ______.

GATE 2017

Answer: 0.9

The Sherwood number (Sh_L) correlation for laminar flow over a flat plate of length L is given by

Where, Re_L and Sc represent Reynolds number and Schmidt number, respectively.

This correlation, expressed in the form of Chilton-Colburn j_D factor, is

GATE 2017

Answer: (B)

Ina counter current stripping operation using pure steam, the mole ratio of a solute in the liquid stream is reduced from 0.25 to 0.05. The liquid feed flow rate, on a solute-free basis, is 3 mol/s. The equilibrium line for the system is given in the figure below.

The MINIMUM flow rate of pure steam for this process, rounded to 1 decimal place, is _____ mol/s.

GATE 2017

Answer: 4

A binary distillation column is to be designed using McCabe Thiele method. The distillate contains 90 mol% of the more volatile component. The point of intersection of the q-line with the equilibrium curve is (0.5, 0.7). The minimum reflux ratio (rounded off to the first decimal place) for this operation is _______.

GATE 2016

Answer: 1

Solute C is extracted in a batch process from its homogenous solution of A and C, using solvent B. The combined composition of the feed and the extracting solvent is shown in the figure below as point M, along with the tie line passing through it. The ends of the tie line are on the equilibrium curve.

What is the selectivity for C?

(A) 3.5

(B) 7

(D) 21

GATE 2016

Answer: (C)

At 30⁰C, the amounts of acetone adsorbed at partially pressures of 10 and 100 mmHg are 0.1 and 0.4 kg acetone/kg activated carbon, respectively. Assume Langmuir isotherm describes the adsorption of acetone on activated carbon. What is the amount of acetone adsorbed (in kg per kg of activated carbon) at a partial pressure of 50 mm Hg and 30⁰C?

(A) 0.23

(B) 0.25

(D) 0.35

GATE 2016

Answer: (C)

Consider the following two cases for a binary mixture of ideal gases A and B under steady state conditions. In Case 1, the diffusion of A occurs through non-diffusing B. In Case 2, equimolal counter diffusion of A and B occurs. In both the cases, the total pressure is 100 kPa and the partial pressures of A at two points separated by a distance of 10 mm are 10 kPa and 5 kPa. Assume that the Fick’s first law of diffusion is applicable. What is the ratio of molar flux of A in Case 1 to that in Case 2?

(A) 0.58

(B) 1.08

(D) 2.18

GATE 2016

Answer: (B)

A binary liquid mixture of benzene and toluene contains 20 mol% of benzene. At 350 K the vapour pressures of pure benzene and pure toluene are 92 kPa and 35 kPa, respectively. The mixture follows Raoult’s law. The equilibrium vapour phase mole fraction (rounded off to the second decimal place) of benzene in contact with this liquid mixture at 350 K is _______.

GATE 2016

Answer: 0.4

Match the dimensionless numbers in Group-1 with the ratios in Group-2.

	Group-1		Group-2
P	Biot number	I	Buoyancy force/viscous force
Q	Schmidt number	II	Inter thermal resistance of a solid/boundary layer thermal resistance
R	Grashof number	III	Momentum diffusivity /mass diffusivity

(A) P-II, Q-I, R-III

(B) P-I, Q-III, R-II

(D) P-II, Q-III, R-I

GATE 2016

Answer: ()

For what value of Lewis number, the wet-bulb temperature and adiabatic saturation temperature are nearly equal?

(A) 0.33

(B) 0.5

(D) 2

GATE 2016

Answer: (C)

A multi-stage, counter-current liquid-liquid extractor is used to separate solute C from a binary mixture (F) of a and C using solvent B. Pure solvent b is recovered from the raffinate R by distillation, as shown in the schematic diagram below.

Locations of different mixtures for this process are indicated on the triangular diagram below. P is the solvent-free raffinate, E is the extract, F is the feed and Δ is the difference point from which the mass balance lines originate. The line PB intersects the bimodal curve at U and T. The lines PΔ and FB intersect the bimodal at V and W respectively.

The raffinate coming out of the extractor is represented in the diagram by the point:

(A) T

(B) U

(D) W

GATE 2015

Answer: (B)

A binary feed consisting of 25 mol% liquid and 75 mol% vapour is separated in a staged distillation column. The mole fraction of the more volatile component in the distillate product is 0.95. The molar flow rate of distillate is 50% of the feed flow rate and the McCabe-Thiele method can be used to analyze the column. The q-line intersects the operating line of the enriching section at (0.35, 0.5) on the x - y diagram. The slope of the stripping section operating line (up to one decimal place) is __________.

GATE 2015

Answer: 1.4

Consider a steady state mass transfer process between well-mixed liquid and vapour phases of a binary mixture comprising of components A and B. The mole fractions of component A in the bulk liquid (x_A) and bulk vapour (y_A) phases are 0.36 and 0.16, respectively. The mass transfer coefficients for component A in liquid and vapour phases are 0.1 mol/(m².s) and 0.05 mol/(m².s), respectively. The vapour-liquid equilibrium can be approximated as y_A^* = 2x_A, for x_A less than 0.4. The mole fraction of A in the liquid at the interface (up to two decimal places) is _____________.

GATE 2015

Answer: 0.22

Adsorption on activated carbon is to be used for reducing phenol concentration in wastewater from 0.04 mol/l to 0.008 mol/l. The adsorption isotherm at the operating temperature can be expressed as q = 0.025 C^1/3; where q is the phenol concentration in solid (mol/g solid) and C is the phenol concentration in water (mol/l). The minimum amount of solid (in grams) required per liter of wastewater (up to one decimal place) is _____________.

GATE 2015

Answer: 6.4

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-20T14:37:00.007+05:30

For a binary mixture of components A and B, N_A and N_B denote the total molar fluxes of components A and B, respectively. J_A and J_B are the corresponding molar diffusive fluxes. Which of the following is true for equimolar counter-diffusion in the binary mixture?

(A) N_A + N_B = 0 and J_A +J_B ≠ 0

(B) N_A + N_B ≠ 0 and J_A +J_B = 0

(D) N_A + N_B = 0 and J_A +J_B = 0

GATE 2015

Answer: (D)

Benzene is removed from air by absorbing it in a non-volatile wash-oil at 100 kPa in a counter-current gas absorber. Gas flow rate is 100 mol/min, which includes 2 mol/min of benzene. The flow rate of wash-oil is 50 mol/min. Vapour pressure of benzene at the column conditions is 50 kPa. Benzene forms an ideal solution with the wash-oil and the column is operating at steady state. Gas phase can be assumed to follow ideal gas law. Neglect the change in molar flow rates of liquid and gas phases inside the column.

For this process, the value of the absorption factor (up to two decimal places) is ___________.

GATE 2015

Answer: 1.02

A spherical naphthalene ball of 2 mm diameter is subliming very slowly in stagnant air at 25°C. The change in the size of the ball during the sublimation can be neglected. The diffusivity of naphthalene in air at 25°C is 1.1×10^-6 m²/s.

The value of mass transfer coefficient is B×10^-3 m/s, where B (up to one decimal place) is ________.

GATE 2015

Answer: 1.1

Identify the WRONG statement amongst the following:

(A) Steam distillation is used for mixtures that are immiscible with water

(B) Vacuum distillation is used for mixtures that are miscible with water

(D) Vacuum distillation columns have larger diameters as compared to atmospheric columns for the same throughput

GATE 2015

Answer: (C)

Packed towers are preferred for gas-liquid mass transfer operations with foaming liquids because

(A) In packed tower, high liquid to gas ratios are best handled

(B) In packed towers, continuous contact of gas and liquid takes place

(D) In packed towers, the gas is not bubbled through the liquid pool

GATE 2014

Answer: (D)

A spherical storage vessel is quarter-filled with toluene. The diameter of the vent at the top of the vessel is 1/20^th of the diameter of the vessel. Under the steady state condition, the diffusive flux of toluene is maximum at

(A) The surface of the liquid

(B) The mid-plane of the vessel

(D) A distance 20 times the diameter of the vent away from the vent

GATE 2014

Answer: (C)

Assuming the mass transfer coefficients in the gas and the liquid phases are comparable, the absorption of CO₂ from reformer gas (CO₂+H₂) into an aqueous solution of diethanolamine is controlled by

(A) Gas phase resistance

(B) Liquid phase resistance

(D) Composition of the reformer gas

GATE 2014

Answer: (A)

Which one of the following statements is CORRECT for the surface renewal theory?

(A) Mass transfer takes place at steady state

(B) Mass transfer takes place at unsteady state

(D) Mass transfer depends only on the film resistance

GATE 2014

Answer: (B)

A spherical ball of benzoic acid (diameter = 1.5 cm) is submerged in a pool of still water. The solubility and diffusivity of benzoic acid in water are 0.03 kmol/m³ and 1.25×10^-9 m²/s respectively. Sherwood number is given as Sh = 2.0 + 0.6Re^0.5Sc^0.33. The initial rate of dissolution (in kmol/s) of benzoic acid approximately is

(A) 3.54×10^-11

(B) 3.54×10^-12

(D) 3.54×10^-14

GATE 2014

Answer: (B)

A wet solid of 100 kg is dried from a moisture content of 40 wt% to 10 wt%. the critical moisture content is 15 wt% and the equilibrium moisture content is negligible. All moisture contents are on dry basis. The falling rate is considered to be linear. It takes 5 hours to dry the material in the constant rate period. The duration (in hours) of the falling rate period is ___________.

GATE 2014

Answer: 1.22

A binary distillation column is operating with a mixed feed containing 20 mol% vapour. If the feed quality is changed to 80 mol% vapour, the change in the slope of the q-line is _________.

GATE 2014

Answer: 3.75

The packing of an existing absorption tower is replaced with a new type of packing. The height of the packing and the inlet conditions are maintained the same as before. Tests reveal that the number of transfer units is lower than before. This indicates that the tower with the new packing, when compared to that with the old packing, will

(A) Have a higher rate of absorption of the solute from the gas stream

(B) Have a lower rate of absorption of the solute from the gas stream

(D) Have a lower height of transfer unit

GATE 2013

Answer: (B)

The vapor-liquid equilibrium curve of a binary mixture A - B, may be approximated by a linear equation over a narrow range of liquid mole fractions (0.2 < x_A < 0.3) as follows

y_A = 1.325x_A + 0.121

Here y_A is the mole fraction of A in the vapor. 100 moles of a feed (x_AF = 0.28) is batch distilled to a final residue (x_AW = 0.2). Using the Rayleigh equation, the number of moles of the residue left behind in the distillation unit, up to 2 digits after the decimal point, is ____________.

GATE 2013

Answer: 66.7

A wet solid is dried over a long period of time by unsaturated air of nonzero constant relative humidity. The moisture content eventually attained by the solid is termed as the

(A) Unbound moisture content

(B) Bound moisture content

(D) Equilibrium moisture content

GATE 2013

Answer: (D)

A crosscurrent cascade of N ideal stages is used to treat a feed stream of molar flow rate E. The feed stream contains a solute which is to be recovered by a pure solvent having a molar flow rate S. The solvent is divided equally between these N stages. The linear equilibrium curve relating the mole fractions x and y* of the solute in the raffinate and the extract respectively, is given by y* = m x. Assume dilute conditions. The ratio of the solute mole fraction in the original feed to that in the exit raffinate stream i. e. (X₀/X_N) is given by

GATE 2013

Answer: (A)

A study was conducted in which water was pumped through cylindrical pipes made of a sparingly soluble solid. For a given pipe and certain flow conditions, the mass transfer coefficient k_c has been calculated as 1 mm/s using the correlation

Sh = 0.025 Re^0.6 Sc^0.33

If the velocity of the fluid and the diameter of the pipe are both doubled, what is the new value of k_c in mm/s, up to 2 digits after the decimal point? _____________

GATE 2013

Answer: 1.15

Common statement for the next two questions

The vapour liquid equilibrium relation for an ideal binary system is given by

Here x_A and are the mole fractions of species A in the liquid and vapour, respectively. The relative volatility (α_AB) is greater than unity.

The liquid mole fraction x_A at which the maximum difference between the equilibrium vapour mole fraction and liquid mole fraction occurs is

GATE 2013

Answer: (A)

A liquid having the composition found in the first part of the linked answer question, is flash distilled at a steady state to a final liquid mole fraction of 0.25. If α_AB is 2.5, the fraction of the feed vaporized is

(A) 0.08

(B) 0.20

(D) 0.74

GATE 2013

Answer: (C)

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-19T14:17:00.011+05:30

An equimolar mixture of A and B (A being more volatile) is flash distilled continuously at a feed rate of 100 kmol/h, such that the liquid product contains 40 mol% of A. If the relative volatility is 6, then the vapour product in kmol/h is

(A) 10

(B) 20

(D) 45

GATE 2012

Answer: (C)

Consider the drying operation shown in the figure below for a solid loading (dry basis) of 50 kg/m² with a constant drying rate of 5 kg/m².h. The falling rate of drying is linear with moisture content.

The drying time in hours required to reduce an initial moisture content of 25% to a final moisture content of 2% is

(A) 1.55

(B) 1.75

(D) 4.55

GATE 2012

Answer: (C)

In the Mc-Cabe-thiele diagram, if the x-coordinate of the point of intersection of the q-line and the vapour-liquid equilibrium curve is greater than the x-coordinate of the feed point, then the quality of the feed is

(A) Superheated vapour

(B) Liquid below bubble point

(D) Saturated liquid

GATE 2012

Answer: (B)

For which of the following combinations, does the absorption operation become gas-film controlled?

(P) The solubility of gas in the liquid is very high

(Q) The solubility of gas in the liquid is very low

(R) The liquid-side mass transfer coefficient is much higher than the gas-side mass transfer coefficient

(S) The liquid-side mass transfer coefficient is much lower than the gas-side mass transfer coefficient

(A) P & Q

(B) P & R

(D) Q & R

GATE 2012

Answer: (B)

Common data for the next two questions

A counter-current extraction column is designed to remove 99% of solute C from a solution of solvent A and solute C using pure solvent B. the initial concentration of solute in the solution of A + C is 20 wt%, and the total flow of solution is 1000 kg/h. If the equilibrium relationship is Y = 2X, where Y = mass of C/mass of A and X = mass of C/mass of B.

The minimum flow rate of solvent B required in kg/h is

(A) 1454

(B) 1584

(D) 1874

GATE 2012

Answer: (B)

If the flow rate of B is 2400 kg/h, then the theoretical number of stages in the column, using Kremser’s equation adjusted to the next integer is

(A) 5

(B) 9

(D) 13

GATE 2012

Answer: (B)

Common Data for the next two questions

A binary feed mixture containing equimolar quantities of components S and T is to be distilled in a fractionating tower at atmospheric pressure. The distillate contains 96 mol % S. The q-line (feed line) intersects the equilibrium line at x' = 0.46 and y'= 0.66, where x' and y' are mole fractions. Assume that the McCabe-Thiele method is applicable and the relative volatility is constant.

The minimum reflux ratio is

(A) 1.6

(B) 1.5

(D) 0.6

GATE 2011

Answer: (B)

The feed is

(A) At dew point

(B) At bubble point

(D) Partially vapour

GATE 2011

Answer: (D)

A gas mixture is in contact with a liquid. Component P in the gas mixture is highly soluble in the liquid. Possible concentration profiles during absorption of P are shown in the choices, where

x: mole fraction of P in bulk liquid

y: mole fraction of P in bulk gas

x_i: mole fraction of P at the interface in liquid

y_i: mole fraction of P at the interface in gas

y*: equilibrium gas phase mole fraction corresponding to x_i

The CORRECT profile is

GATE 2011

Answer: (A)

Ammonia (component 1) is evaporating from a partially filled bottle into surrounding air (component 2). The liquid level in the bottle and the concentration of ammonia at the top of the bottle are maintained constant. N_i is the molar flux relative to a fixed location in space and J_i is the molar flux with respect to the average molar velocity of the constituent species in the gas phase. Assume that air in the bottle is stagnant. Which ONE of the following is CORRECT?

(A) N₁ = constant, N₂ = 0, J₁ +J₂ = 0

(B) N₁ + N₂ = 0, J₁ +J₂ = 0

(D) N₁ = constant, N₂ = 0, J₁ = constant, J₂ = 0

GATE 2011

Answer: (A)

A batch of 120 kg wet solid has initial moisture content of 0.2 kg water/kg dry solid. The exposed area for drying is 0.05 m²/kg dry solid. The rate of drying follows the curve given below.

The time required (in hours) for drying this batch to a moisture content of 0.1 kg water/kg dry solid is

(A) 0.033

(B) 0.43

(D) 2.31

GATE 2011

Answer: (D)

Simultaneous heat and mass transfer is occurring in a fluid flowing over a flat plate. The flow is laminar. The concentration boundary layer will COINCIDE with the thermal boundary layer, when

(A) Sc = Nu

(B) Sh = Nu

(D) Sc = Pr

GATE 2011

Answer: (D)

The flooding velocity in a plate column, operating at 1 atm pressure, is 3 m/s. If the column is operated at 2 atm pressure, under otherwise identical conditions, the flooding velocity will be

GATE 2010

Answer: (A)

At 25⁰C and 90% relative humidity, water evaporates from the surface of a lake at the rate of 1.0 kg/m²/h. The relative humidity that will lead to an evaporation rate of 3.0 kg/m²/h, with other conditions remaining the same, is

(A) 30%

(B) 50%

(D) 70%

GATE 2010

Answer: (D)

Common Statement for the next two questions

Water is used to absorb ammonia from a gas mixture in a single separation stage contactor. The process is schematically represented in the figure below.

The molar gas and liquid flow rates, and the inlet mole fractions are given in the figure. Both the liquid and the gas phases are well mixed, and the equilibrium relation between y and x is given by y^* = x.

If the stage is ideal, then the value of y is

(A) 1/15

(B) 1/10

(D) 1/6

GATE 2010

Answer: (A)

If the stage efficiency is 50%, then the value of y is

(A) 1/12

(B) 1/6

(D) 1/3

GATE 2010

Answer: (A)

A liquid flows over a flat naphthalene plate of length L, at a Reynolds number (Re_L = Lρu_∞/μ) of 1500, as shown in the figure. The surface concentration of naphthalene is C_AI > C_A∞ and the surface temperature is T_C>T_∞. Assume Pr = Sc = 1.

Then the Nusselt number and the friction coefficient at x= L, are

(A) 10, 1/75

(B) 10, 10

(D) 1/75, 5

GATE 2010

Answer: (A)

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-18T14:08:00.002+05:30

According to the penetration theory of mass transfer, the mass transfer coefficient (k) varies with diffusion coefficient (D) of the diffusing species as

(A) D

(B) D^-1/2

(D) D^3/2

GATE 2009

Answer: (C)

The ratio of the liquid to gas flow rate in a counter-current gas absorption column is increased, at otherwise identical conditions. Which one of the following statements is true?

(A) The operating line shifts towards the equilibrium curve

(B) The operating line shifts away from the equilibrium curve

(D) The operating line does not shift

GATE 2009

Answer: (B)

Species A is diffusing at steady state from the surface of a sphere (radius = 1 cm) into a stagnant fluid. If the diffusive flux at a distance r = 3 cm from the center of the sphere is 27 mol/cm².s, the diffusive flux (in mol/cm².s) at a distance r = 9 cm is

(A) 1

(B) 3

(D) 27

GATE 2009

Answer: (B)

The feed to a binary distillation column has 40 mol % vapour and 60 mol % liquid. Then, the slope of the q-line in the McCabe-Thiele plot is

(A) -1.5

(B) -0.6

(D) 1.5

GATE 2009

Answer: (A)

The equilibrium moisture curve for a solid is shown below:

The total moisture content of the solid is X and it is exposed to air of relative humidity H. In the table below, Group I lists of the type of moisture, and Group II represents the region in the graph above

Group I	Group II
P. Equilibrium moisture	1
Q. Bound moisture	2
R. Unbound moisture	3
S. Free moisture	4

Which one of the following is the correct match?

(A) P-I, Q-2, R-3, S-4

(B) P-I, Q-3, R-4, S-2

(D) P-I, Q-2, R-4, S-3

GATE 2009

Answer: (B)

An equimolar mixture of four hydrocarbons (1, 2, 3, 4) is to be separated into high purity individual components using a sequence of simple distillation columns (one overhead and one bottom stream). Four possible schemes are shown below.

Component	K_i
1	6
2	3
3	2.5
4	1.1

Using the K_i (= y_i^*/x_i) values given above, the optimal scheme is

(A) P

(B) Q

(D) S

GATE 2009

Answer: (D)

Common data for the next two questions

A flash distillation drum (see figure below) is used to separate a methanol –water mixture. The mole fraction of methanol in the feed is 0.5, and the feed flow rate is 1000 kmol/hr. The feed is preheated in a heater with heat duty Q_h and is subsequently flashed in the drum. The flash drum can be assumed to be an equilibrium stage, operating adiabatically. The equilibrium relation between the mole fractions of methanol in the vapour and liquid phases is y^* = 4x. The ratio of distillate to feed flow rate is 0.5.

The mole fraction of methanol in the distillate is

(A) 0.2

(B) 0.7

(D) 0.9

GATE 2009

Answer: (C)

If the enthalpy of the distillate with reference to the feed is 3000 kJ/kmol, and the enthalpy of the bottoms with reference to the feed is -1000 kJ/kmol, the heat duty of the preheater (Q_h in kJ/hr) is

(A) -2×10⁶

(B) -1×10⁶

(D) 2×10⁶

GATE 2009

Answer: (C)

For a system containing species P, Q and R, composition at point k on the ternary plot is

(A) 62.5% P, 12.5% Q, 25% R

(B) 25% P, 62.5% Q, 12.5% R

(D) 12.5% P, 25% Q, 62.5% R

GATE 2008

Answer: (A)

In a countercurrent gas absorber, both the operating and equilibrium relations are linear. The inlet liquid composition and the exit gas composition are maintained constant. In order to increase the absorption factor

(A) The liquid flow rate should decrease

(B) The gas flow rate should increase

(D) The slope of the equilibrium line should decrease

GATE 2008

Answer: (D)

A rectangular slab of thickness 2b along the x axis and extending to infinity along the other directions is initially at concentration C_A0. At time t = 0, both surfaces of the slab (x = ±b) have their concentrations increased to C_AW and maintained at that value. Solute A diffuses into the solid. the dimensionless concentration C is defined as

C = (C_A-C_A0)/(C_AW – C_A0)

The diffusivity of A inside the solid is assumed constant. At a certain time instant, which one of the following is the correct representation of the concentration profile?

GATE 2008

Answer: (C)

In a binary mixture containing components A and B, the relative volatility of A with respect to B is 2.5 when mole fractions are used. The molecular weights of A and B are 78 and 92 respectively. If the compositions are however expressed in mass fractions the relative volatility will then be

(A) 1.18

(B) 2.12

(D) 2.95

GATE 2008

Answer: (C)

An ideal flash vaporization is carried out with a binary mixture at constant temperature and pressure. A process upset leads to an increase in the mole fraction of the heavy component in the feed. The flash vessel continues to operate at the previous temperature and pressure and still produces liquid and vapour. After steady state is re-established,

(A) The amount of vapour produced will increase

(B) The amount of liquid produces will decrease

(D) The new equilibrium compositions of the vapour and liquid products will remain as they were before the upset occurred

GATE 2008

Answer: (D)

A batch distillation operation is carried out to separate a feed containing 100 moles of a binary mixture of A and B. The mole fraction of A in the feed is 0.7. The distillation progress until the mole fraction of A in the residue decreases to 0.6. The equilibrium curve in this composition range may be linearized to y^* = 0.7353x + 0.3088. Here x and y are the mole fractions of the more volatile component A in the liquid and vapour phases respectively. The number of moles of residue is

(A) 73.53

(B) 48.02

(D) 30.24

GATE 2008

Answer: (B)

A packed tower containing Berl saddles is operated with a gas-liquid system in the countercurrent mode. Keeping the gas flow rate constant, if the liquid flow rate is continuously increased,

(A) The void fraction available for the gas to flow will decrease beyond the loading point

(B) The gas pressure drop will decrease

(D) The entrainment of liquid in the gas will considerably decrease near the flooding point

GATE 2008

Answer: (A)

A sparingly soluble solute in the form of a circular disk is dissolved in an organic solvent as shown in the figure. The area available for mass transfer from the disk is A and the volume of the initially pure organic solvent is V. The disk is rotated along the horizontal plane at a fixed rpm to produce a uniform concentration of the dissolving solute in the liquid.

The convective mass transfer coefficient under these conditions is k_c. The equilibrium concentration of the solute in the solvent is C^*. The time required for the concentration to reach 1% of the saturation value is given by

GATE 2008

Answer: (A)

Air concentrated with solute P is brought in contact with water. At steady state, the bulk concentrations of P in air and water are 0.3 and 0.02 respectively. The equilibrium equation relating the interface compositions is

y_P,i = 0.25x_P,i

Assume that the mass transfer coefficients F_G and F_L are identical. The gas phase mole fraction of P at the interface (y_P,i) is

(A) 0.0663

(B) 0.075

(D) 0.3

GATE 2008

Answer: (A)

A feed (F) containing a solute is contacted with a solvent (S) in an ideal stage as shown in the diagram below. Only the solute transfer into the solvent. The flow rates of all the streams are shown on a solute free basis and indicated by the subscript S. The compositions of the streams are expressed on a mole ratio basis. The extract leaving the contactor is divided into two equal parts, one part collected as the product (P) and the other stream is recycled to join the solvent. The equilibrium relationship is

Y^* = 2X

The product flow rate (P_s) and composition (Y_out) are

(A) P_s = 50 mol/s, Y_out = 0.3

(B) P_s = 100 mol/s, Y_out = 0.2

(D) P_s = 100 mol/s, Y_out = 0.4

GATE 2008

Answer: (B)

Common statement for the next two questions

A thin liquid film flows at steady state along a vertical surface as shown in the figure. The average velocity of the liquid film is 0.05 m/s. The viscosity of the liquid is 1 cP and its density is 1000 kg/m³. The initially pure liquid absorbs a sparingly soluble gas from air as it flows down. The length of the wall is 2 m and its width is 0.5 m. The solubility of the gas in the liquid is 3.4×10^-2 kmol/m³ and isothermal conditions may be assumed.

If the exit average concentration in the liquid is measured to be 1.4×10^-2 kmol/m³, the total mass transfer rate (in kmol/s) of the sparingly soluble gas into the liquid is

(A) 0.133×10^-4

(B) 0.434×10^-7

(D) 17×10^-2

GATE 2008

Answer: (B)

The mass transfer coefficient k_c,avg (in m/s), averaged along the length of the vertical surface is

(A) 2.94×10^-6

(B) 2.27×10^-6

(D) 1.65×10^-6

GATE 2008

Answer: (D)

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-17T16:16:00.003+05:30

The following figure depicts steady one-dimensional diffusion of water vapour from the surface of water taken in a conical flask at room temperature. Derive the governing equation for determining the concentration profile of water vapour in the gas medium. Neglect change of level of water due to condensation. The temperatures of the gas and the liquid media are identical and constant.

GATE 2007

Answer: (A)

If T_A and T_B are the boiling points of pure A and B respectively and T_AB is that of a non homogeneous immisible mixture of A and B, then

(A) T_AB<T_A and T_B

(B) T_AB>T_A and T_B

(D) T_B>T_AB>T_A

GATE 2007

Answer: (A)

In a distillation operation, it is desired to have a very high purity bottom product. Initially, a kettle-type reboiler is used at the bottom of the column and the following analytical equation is used to obtain the equilibrium trays in the exhausting section of the column.

Where x_m is the composition of the liquid leaving tray m. Tray m is the last equilibrium tray obtained by a McCabe Thiele graph of the exhausting section. If the kettle-type reboiler is replaced by a thermo-syphon reboiler, the analytical equation, for the exhausting section will be

GATE 2007

Answer: (C)

A 50 cm × 50 cm × 1 cm flat wet sheet weighing 2 kg initially, was dried from both the sides under constant drying rate period. It look 1000 secs for the weight of the sheet to reduce to 1.75 kg. Another 1 m × 1 m × 1 cm flat sheet is to be dried from one side only. Under the same drying rate and other conditions, time required for drying (in secs) from initial weight of 4 kg to 3 kg is

(A) 1000

(B) 1500

(D) 2500

GATE 2007

Answer: (C)

It is desired to reduce the concentration of pyridine in 500 kg of aqueous solution from 20 weight percent to 5 wt percent in a single batch extraction using chlorobenzene as solvent. Equilibrium compositions (end points of the tie line) in terms of weight percent of pyridine-water-chlorobenzene are (5, 95, 0) and (11, 0, 89). The amount of pure solvent required in kg for the operation is

(A) 607

(B) 639

(D) 1501

GATE 2007

Answer: (B)

Benzene in an air-benzene mixture is to be reduced from 5.2 mol% in the feed to 0.5 mol% by contacting with wash oil in a multistage countercurrent gas absorber. The inlet flow rate of air-benzene mixture is 10 mol/s while benzene free wash oil comes in at 9.5 mol/s. If the equilibrium curve is given as Y* = X, where Y* and X are equilibrium mole ratios of benzene in air and benzene in oil, the number of equilibrium stages required to achieve the above separation is

(A) 12

(B) 10

(D) 6

GATE 2007

Answer: (B)

Given the following statements listed from P to T, select the correct combination of TRUE statements from the choices that follow this list.

(P) Plate columns are preferred when the operation involves liquids containing suspended solids.

(Q) Packed towers are preferred if the liquids have a large foaming tendency.

(R) The pressure drop through packed towers is more than the pressure drop through plate columns designed for the same duty

(S) Packed columns are preferred when large temperature changes are involved in distillation operations.

(T) Packed towers are cheaper than plate towers if highly corrosive fluids must be handled.

(A) T, S, P

(B) P, Q, T

(D) R, Q, S

GATE 2007

Answer: (B)

If the percentage humidity of air (30°C, total pressure 100 kPa) is 24% and the saturation pressure of water vapour at that temperature is 4 kPa, the percent relative humidity and the absolute humidity of air are

(A) 25.2, 0.0062

(B) 25, 0.0035

(D) 18.2, 0.0035

GATE 2007

Answer: (A)

Common data for the next three questions

A binary distillation column separates 100 mol/h of a feed mixture into distillate D and residue W. The McCabe-Thiele diagram for this process is given below. The relative volatility for the binary system is constant at 2.4

The distillate and residue flow rates (in mol/h) are

(A) D = 48.4, W = 51.6

(B) D = 51.6, W = 48.4

(D) D = 45.3, W = 54.7

GATE 2006

Answer: (A)

The ratio of liquid to vapour molar flow rates in the rectifying section is

(A) 0.64

(B) 1.00

(D) 1.80

GATE 2006

Answer: (A)

The minimum number of theoretical stages (inclusive of reboiler) for this process is

(A) 5.2

(B) 6.1

(D) Infinite

GATE 2006

Answer: (C)

A saturated vapour is fed to a distillation column at 180 kmol/h. Both the rectifying and stripping section of the column operate at 60% of their respective flooding velocities. The flooding velocity of the rectifying section is twice that of the stripping section. The assumptions of constant molar overflow and constant molar vapour density throughout the column are valid. If the boil-up rate is 60 kmol/h, then the relationship between the diameters of the rectifying section (d_r) and the stripping section (d_s) is

GATE 2006

Answer: (A)

Experiments conducted with a sparingly dissolving cylinder wall in a flowing liquid yielded the following correlation for the Sherwood number

Sh = 0.023(Re)^0.83(Sc)^1/3

Assuming the applicability of the Chilton-Colburn analogy, the corresponding correlation for heat transfer is

(A) St = 0.023(Gr)^0.83(Pr)^1/3

(B) Sh = 0.023(Re)^0.83(Pr)^1/3

(D) Nu = 0.069(We)^0.5(Pr)^4/3

GATE 2006

Answer: (B)

A drug tablet of mass M₀ administered orally at time t = 0 reaches the intestine at time t = τ without losing any mass. From the intestine, the drug is absorbed into blood. The rate of absorption is found to be proportional to the mass of the drug in the intestine with the proportional constant k. Assuming no drug is lost from the blood, the total mass of the drug in the blood M_b at time t ≥ τ is given by

(A) M_b = M₀[1-exp{-k(t-τ)}]

(B) M_b = M₀[1-exp{-kτ)}]

(D) M_b = M₀[1-exp{-k(t+τ)}]

GATE 2006

Answer: (C)

100 mol of a binary mixture F containing 60 mol% A (more volatile) and 40% B is treated in a batch distillation still. After 1 h, 70 mol of the distillate are collected leaving behind the residue W. Relative volatility α is 2. The governing equation is

Log(Fx_F/Wx_W) = α log[{F(1-x_F)}/{W(1-x_W)}]

The average mole fraction of A in the distillate is

(A) 0.43

(B) 0.61

(D) 0.73

GATE 2006

Answer: (C)

In a multistage counter current isothermal stripping column, the feed containing 0.05 mol of solute/mol solute free oil is treated with steam. The absorption factor A = 0.65. The equilibrium relation is given by Y^* = 2X, where Y^* and X refer to the equilibrium mole ratio in the steam and oil phases respectively. The Kremsen equation is given as follows (‘0’ refers liquid inlet at the top, N_P refers to the last stage at the bottom).

If the steam is initially free of solute and its exit molar ratio (mol solute/mol steam) is 0.0624, then the number of equilibrium stages required is

(A) 4.2

(B) 5.2

(D) 8.2

GATE 2006

Answer: (B)

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-16T13:56:00.006+05:30

An ideal single stage extraction process is used to treat 100 mol/s of an organic feed solution. The solute concentration in this solution is to be reduced from 0.5 mol% to 0.1 mol%. A pure solvent S is used. To reduce the solvent requirement by half for the same separation,

(A) Add one more ideal co-current stage

(B) Use another pure solvent S*whose partition coefficient is twice that of S

(D) Double the residence time of the solvent S in the contactor

GATE 2006

Answer: (B)

Common statement for the next two questions

Consider the diffusion of a reactant A through a cylindrical catalyst pore of radius R and length L>>R. Reactant A undergoes a zero order reaction on the cylindrical surface of the pore. The following equation describes changes in the concentration of A within the pore due to the axial diffusion of A and the disappearance of A due to reaction d²C_A/dx²=K, where C_A is the concentration of A at a distance from the pore entrance and K is a constant.

The minimum pore length for A to be completely converted within the pore is

(A) (C_A0/K)^1/2

(B) (C_A0/2K)^1/2

(D) (2C_A0/K)^1/2

GATE 2006

Answer: (D)

If the concentration of A at the pore entrance (x = 0) is C_A0 and x = L is a dead end where no reaction occurs, the concentration profile of A in the pore is given by

(A) C_A(x) = Kx²/2 – KLx + C_A0

(B) C_A(x) = Kx(x-L)/2 – C_A0x/L + C_A0

(D) C_A(x) = C_A0((L-x)/L)

GATE 2006

Answer: (B)

The ratio of diffusion coefficient in a gas to that in a liquid is of the order of

(A) 10⁵

(B) 10^-5

(D) 10²

GATE 2005

Answer: (A)

In a tray column, separating a binary mixture, with non-ideal stages. One of the following statement is TRUE.

(A) Point efficiency can exceed 100%

(B) Murphree efficiency cannot exceed 100%

(D) Both Murphree and point efficiencies can exceed 100%

GATE 2005

Answer: (C)

A distillation column at a pilot plant is scaled up by 3 times for industrial use at steady state. After scaling up

(A) The number of theoretical trays increases by 3 times

(B) The minimum reflux ratio is increased by three times

(D) The feed composition and product compositions are increased by three times

GATE 2005

Answer: (C)

A separation column for vapour-liquid contact processes 200 kmol/hr of vapour. The flooding velocity is 3 m/s. If the column operates at 85% of flooding velocity and the down comer area is !0% of the total cross sectional area, what is diameter of the column? Average density of vapour = 2 kg/m³ and its molecular weight = 44.

(A) 0.82 m

(B) 0.72 m

(D) 1 m

GATE 2005

Answer: (A)

Match the variation of mass transfer coefficient given by the theory in Group –I with the appropriate variation in Group –II

(A) P – 1, Q – 2, R – 3

(B) P – 2, Q – 1, R – 3

(D) P – 3, Q – 2, R – 1

GATE 2005

Answer: (C)

Two solid discs of benzoic acid (molecular weight = 122) of equal dimensions are spinning separately in large volumes of water and air at 300 K. the mass transfer coefficients for benzoic acid in water and air are 0.9×10^-5 and 0.4710^-2 m/s respectively. The solubility of benzoic acid in water is 3 kg/m³ and the equilibrium vapour pressure of benzoic acid in air is 0.04 Kpa. Then the disc

(A) Dissolves faster in air than in water

(B) Dissolve faster in water than in air

(D) Does not dissolve either in water or in air

GATE 2005

Answer: (B)

For a two phase feed, where 80% of the feed is vaporized under column conditions, the feed line slope in the Mcabe-Thiele method for distillation column design, is

(A) -1/4

(B) +1/4

(D) - 4

GATE 2005

Answer: (A)

In the triangular diagram represented below for a batch separation process, a stream F, is mixed with a solvent B to produce products R and E. Substance A is the carrier liquid and c is the solute to be extracted. The amounts of B and E are 1 kg and 1.20 kg respectively. The length FM is 3.1 and length FB is 8.5 units on the figure. The ratio R/E is estimated to be

(A) 1.285

(B) 2

(D) 2.5

GATE 2005

Answer: (A)

A filter cake is dried with air at wet and dry bulb temperatures of 300 and 323 K respectively. The heat transfer coefficient is 11 W/(m²K) and the latent heat of vaporization of water is 2500 KJ/kg. Mass transfer does not limit the process. Select the drying rate during the constant rate period. Neglect conduction through the solid and radiation effects.

(A) 1.32×10^-2 Kg m^-2 s^-1

(B) 0.71×10^-2 Kg m^-2 s^-1

(D) 0.10×10^-3 Kg m^-2 s^-1

GATE 2005

Answer: (D)

Common Statement for the next two questions

A binary gas mixture of a solute and a carrier gas is treated in a countercurrent gas absorption column, containing ideal trays, using a solvent. The compositions y and x (see figure below) are the mole fractions of the solute in the gas and liquid respectively. Also V and L are the molar flow rates of the gas liquid respectively. Assume that the carrier gas is insoluble in the solvent and that the vapour pressure of the solvent is very low at the given conditions of the column. Further the gas and liquid streams are sufficiently dilute that L and v may assumed to be constant throughout the column. The equilibrium relation is given by y* = mx, where m is a positive constant.

For any value of m, the change in liquid composition across a tray is independent of the tray location if

(A) (L/V) = 1

(B) (mL/V) = 1

(D) (L/mV) = 1

GATE 2005

Answer: (D)

Under the correct condition corresponding to part (a), the number of ideal trays in the column is given by

GATE 2005

Answer: (C)

In a distillation operation, what is the effect of the temperature of the reflux stream (given) on the condenser and reboiler loads?

Reflux conditions: (i) reflux stream is completely liquid and is at its bubble point

(ii) reflux stream is below its bubble point

(A) Condenser and reboiler loads are the same in both cases

(B) Reboiler load is the same in both the cases but condenser load is higher in case (ii)

(D) Both condenser and reboiler loads are higher in case (ii) as compared to case (i)

GATE 2004

Answer: (D)

A long cylinder and a sphere both of 5 cm diameter are made from the same porous material. The flat ends of cylinder are sealed. Both the cylinder and sphere are saturated with the same solution of sodium chloride. Later, both the objects are immersed for a short and equal interval of time in a large tank of water, which is well agitated. The fractions of salt remaining in the cylinder and the sphere are X_c and X_s respectively. Which of the following statements is correct?

(A) X_c > X_s

(B) X_c = X_s

(D) X_c is greater /less than X_s depending on the length of the cylinder

GATE 2004

Answer: (C)

At equilibrium, the concentration of water in vapour phase (C^*) in kg/m³ of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by C^* = 0.0667m. To maintain dry conditions in a room of air space 100 m³ containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after long time (during which the temperature is maintained constant) is

(A) 0.0

(B) 0.2

(D) 1.0

GATE 2004

Answer: (C)

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-15T17:11:00.006+05:30

A distillation column with n plates is being operated under normal conditions. At some point in time, the operation is shifted to total reflux conditions (i.e. no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,

(A) Composition of vapours and that of liquid do not vary throughout the column

(B) Reboiler load and condenser load are minimum

(D) The reflux and bottom compositions correspond to the maximum enrichment achievable.

GATE 2004

Answer: (D)

An aqueous solution of methanol is to be distilled in a tray column. High pressure stem is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored: (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii)

(A) Less number of trays required

(B) Composition of the residue remains unchanged

(D) More number of trays are required and the residue composition is more dilute in methanol

GATE 2004

Answer: (A)

A 25 cm×25 cm×1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1 m× 1 m×1 cm flat sheet of the same material is to be dried from one side only. Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 19.6 kg is

(A) 1000

(B) 1500

(D) 2500

GATE 2004

Answer: (C)

Acetone is to be removed from air in an isothermal absorber using pure water as solvent. The incoming air contains 5 mol% of acetone (y_in = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is

N + 2 = 6 log(y_in/y_out)

For 98% recovery of acetone, the number of trays required is/are

(A) 1

(B) 8

(D) 10

GATE 2004

Answer: (C)

Common data for the next two questions

An air-water vapour has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 KPa and the vapour pressures of water at 40°C and 60°C are 7.30 KPa and 19.91 KPa respectively.

The humidity of air sample expressed as kg of water vapour/kg of dry air is

(A) 0.048

(B) 0.079

(D) 0.152

GATE 2004

Answer: (A)

The wet bulb temperature T_w for the above mixture would be

(A) Less than 40°C

(B) 40°C

(D) 60°C

GATE 2004

Answer: (C)

Common data for the next two questions

Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 Kpa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mol/m. The diffusivity of aniline in air is 0.74×10^-5 m²/s.

The numerical value of the mass transfer coefficient is 7.4×10^-3. Its units are

(A) m/s

(B) cm/s

(D) kmol/(m² s Pa)

GATE 2004

Answer: (A)

The rate of evaporation of aniline is 2.97×10^-4. Its units are

(A) mol/s

(B) mol/(cm² s)

(D) kmol/(m² s)

GATE 2004

Answer: (D)

A distillation column operates 10,000 kg/hr of a benzene-toluene mixture as shown in the figure. In the figure x_F, x_D and x_W represent the weight fractions of benzene in the feed, distillate and residue respectively.

The reflux ratio is

(A) 0.5

(B) 0.6

(D) 2.0

GATE 2004

Answer: (B)

Minimum reflux ratio in a distillation column results in

(A) Optimum number of trays

(B) Minimum reboiler size

(D) Minimum number of trays

GATE 2003

Answer: (B)

Component A is diffusing in a medium B. The flux NA relative to a stationary point is equal to the flux due to molecular diffusion if

(A) Diffusion of A is in stagnant medium B

(B) Mass transfer is accompanied by reaction

(D) There is equimolar counter diffusion

GATE 2003

Answer: (D)

The diffusion coefficient, in m2/s, of acetic acid in benzene (liquid in liquid) is

(A) 2.09×10^-4

(B) 2.09×10^-5

(D) 2.09×10^-12

GATE 2003

Answer: (C)

In distillation column sizing calculations by short cut methods, match the following

P	Underwood’s equation	1	Number of real trays
Q	Fenske equation	2	Column diameter
R	Gilliland’s equation	3	Minimum number of ideal trays
S	Vapour velocity at flooding	4	Actual number of ideal trays
		5	Minimum reflux ratio
		6	Tray efficiency

(A) P-1, Q-3, R-4, S-6

(B) P-2, Q-5, R-1, S-3

(D) P-5, Q-3, R-4, S-2

GATE 2003

Answer: (C)

Compound A is extracted from a solution of A + B into a pure solvent S. A co-current unit is used for the liquid-liquid extraction. The inlet rate of the solution containing A is 200 mol of B/h-m² and the solvent flow rate is 400 mol of S/h-m². The equilibrium data is represented by Y = 2X, where Y is in mol of A/mol of B and X is in mol of A/mol of S. The maximum percentage extraction achieved in the unit is

(A) 25%

(B) 50%

(D) 90%

GATE 2003

Answer: (B)

The following plot gives the saturated-humidity (H) versus temperature (T)

Line joining (H₁, T₁) and (H₂, T₂) is the constant enthalpy line. Choose the correct one from the following options.

(A) T₁ = Dew point temp, T₂ = Dry bulb temperature, T₃ = Wet bulb temp

(B) T₁ = Dew point temp, T₂ = Wet bulb temperature, T₃ = Dry bulb temp

(D) T₁ = Dry bulb temp, T₂ = Wet bulb temperature, T₃ = Dew point temp

GATE 2003

Answer: (D)

A solid is being dried in the linear drying rate regime from moisture content X₀ to X_F. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture, X₀. The drying time for m = (L_S/AR_C) is

(A) M(X₀ - X_F)

(B) M(X₀/X_F)

(D) mX₀ ln(X₀/X_F)

Where, L_S = Total mass of dry solids, A = total surface area for drying, R_C = constant maximum drying rate per unit area and X = moisture content (in mass of water/mass of dry solids).

GATE 2003

Answer: (D)

A pure drug is administered as a sphere and as a cube. The amount of drug is the same in the two tablets. Assuming that the shape and size do not influence of mass transfer, the ratio of rate of dissolution in water at t = 0 for the cubic to spherical tablet is

(A) 0.54

(B) 1.04

(D) 1.94

GATE 2003

Answer: (C)

The Reynolds number of the liquid was increased 100 fold for a laminar falling film used for gas liquid contacting. Assuming the penetration theory is applicable, the fold-increase in the mass transfer coefficient (K_c) for tha same system is

(A) 100

(B) 10

(D) 1

GATE 2003

Answer: (B)

H₂S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data given by y = 1.5x. The bulk concentration of H₂S has to be reduced from 0.05 and 0.001 mole fraction in the gas side. The height of the tower (in meter) corresponding to an operating line given by y = 5x + 0.001 is

(A) 2.0

(B) 1.56

(D) 0.56

GATE 2003

Answer: (A)

Experiments were conducted to determine the flux of a species A in a stagnant medium across gas-liquid interface. The overall mass transfer coefficient based on the liquid side for dilute systems for the above was estimated to be 4×10^-3 kg-mol/m²-s. The equilibrium data for the system is given as Y = 2X. The flux across the interface X = 0.01, respectively is concentration of A in gas phase and liquid phase as Y = 0.4 and X = 0.01, respectively is

(A) 5.6×10^-4

(B) 8.5×10^-4

(D) 8.5×10^-3

GATE 2003

Answer: (B)

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GATE Chemical Engineering Questions and Answers - Mass Transfer

2021-08-14T14:48:00.008+05:30

It takes 6 h to dry a wet solid from 50% moisture content to the critical moisture content of 15%. How much longer will it take to dry the solid to 10% moisture content. Under the same drying conditions (the equilibrium moisture content of the solid is 5%).

(A) 15 min

(B) 51 min

(D) 94 min

GATE 2002

Answer: (C)

According to the Fenske equation, what will be the minimum of plates required in a distillation column to separate an equimolar binary mixture of components A and B into an overhead fraction containing 99 mol% A and a bottoms fraction containing 98 mol% B? [Assume that the relative volatility (α_AB = 2) does not change appreciably in the column]

(A) 5

(B) 9

(D) 28

GATE 2002

Answer: (C)

The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is

(A) Nusselt number

(B) Sherwood number

(D) Stanton number

GATE 2002

Answer: (C)

The Reynolds analogy for momentum, heat and mass transfer is best applicable for

(A) Gases in turbulent flow

(B) Gases in laminar flow

(D) Liquids and gases in laminar flow

GATE 2002

Answer: (A)

For gas absorption the height of a transfer unit, based on the gas phase, is given by (G: superficial molar gas velocity; L: superficial molar liquid velocity; F_G: mass transfer coefficient mol/m².S; a: interfacial area per unit volume of tower)

(A) G/F_Ga

(B) F_G/Ga

(D) L/F_GG

GATE 2001

Answer: (A)

The Lewis relation for air-water humidification is given by (k_y: mass transfer coefficient of moisture in air; h_G: heat transfer coefficient; C_s: heat capacity of vapour gas mixture)

GATE 2001

Answer: (C)

The surface renewal frequency in Dankwert’s model of mass transfer is given by (k_L: mass transfer coefficient, m/s)

GATE 2001

Answer: (C)

The interfacial area per unit volume of dispersion in a gas – liquid contactor for frictional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m²/m³)

(A) 500

(B) 1200

(D) 800

GATE 2001

Answer: (B)

For equimolar counter diffusion from a sphere to a surrounding stationary infinite medium, the mass flux N_Ai of the diffusion component A at the interface is given by N_Ai = D_A(C_Ai - C_Ab)/R where D_A is the diffusivity, R the radius of the sphere and C_Ai and C_Ab the molar concentrations of A at the interface and at a point far away from the sphere. Sherwood number based on the diameter of the sphere is equal to

(A) 1

(B) 2

(D) 4

GATE 2001

Answer: (B)

In a single stage extraction process 10 kg of pure solvent S (containing no solute A) is mixed with 30 kg of feed F containing A at a mass fraction X_F = 0.2. The mixture splits into an extract phase E and a raffinate phase R, containing A at X_E = 0.5 and X_R = 0.05 respectively. The total mass of the extract phase is (in kg).

(A) 6.89

(B) 8.89

(D) 8.25

GATE 2001

Answer: (B)

200 kg of solid (on dry basis) is subjected to a drying process for a period of 5000 s. The drying occurs in the constant rate period with the drying rate as NC = 0.5×10^-3 kg/m²-s. The initial moisture content of the solid is 0.2 kg moisture /kg dry solid. The interfacial area available for drying is 4 m²/100 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)

(A) 0.5

(B) 0.05

(D) 0.15

GATE 2001

Answer: (C)

The McCabe ΔL law states that the

(A) Molar heat of vaporization of components are nearly equal.

(B) Linear crystal growth rate depends on the degree of super saturation

(D) Linear crystal growth rate depends on the crystal size.

GATE 2000

Answer: (A)

For the nth tray (counter from the bottom of a distillation column), the Murphree efficiency is given by

GATE 2000

Answer: (B)

At 750 K and 1 atm, the approximate value of the Schmidt number for air is

(A) 0.01

(B) 0.1

(D) 10

GATE 2000

Answer: (B)

In a laboratory test run, the rate of drying was found to be 0.5×10^-3 kg/m² when the moisture content reduced from 0.4 to 0.1 on a dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m²/kg of dry solid. The time required (in second) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is

(A) 2000

(B) 4000

(D) 6000

GATE 2000

Answer: (C)

Consider a system in which component A is being transferred from a gas phase to a liquid phase. The equilibrium relation is given by y_A = 0.75 x_A where y_A and x_A are mole fractions of A in gas and liquid phase respectively. At one point in the equipment, the gas contains 10 mole% A and liquid 2 mole% A. Gas film mass transfer coefficient k_y at this point is 10 kmol/(kr.m².Δy_A) and 60% of the resistance is in the gas film. Calculate the overall mass transfer coefficient in kmol/(hr.m².Δy_A)

(A) 6

(B) 7

(D) 9

GATE 2000

Answer: (A)

The individual mass transfer coefficients (mol/m².S) for absorption of a solute from a gas mixture into a liquid are K_L = 4.5 and K_G = 1.5. the slope of the equilibrium line is 3. Which of the following resistance is (are) controlling?

(A) Liquid side

(B) Gas side

(D) Both liquid and gas side

GATE 2000

Answer: (D)

The absorption factor is defined as

(A) L/mG

(B) G/mL

(D) LG/m

GATE 2000

Answer: (A)

An alkaline solution is used to reduce the concentration of carbon dioxide in a stream 10% to 0.1% by absorption with irreversible chemical reaction. The overall number of transfer units based on gas phase is

(A) 9.21

(B) 4.605

(D) 0.001

GATE 1999

Answer: (B)

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GATE Chemical Engineering Questions and Answers - Mechanical Operations

2021-08-13T15:29:00.008+05:30

In a constant pressure cake filtration with an in-compressible cake layer, volume of the filtrate (V) is measured as a function of time t. The plot of t/V versus V results in a straight line with an intercept of 10⁴ s m^-3. Area of the filter is 0.05 m², viscosity of the filtrate is 10^-3 Pa s, and the overall pressure drop across the filter is 200 KPa. The value of the filter-medium resistance (in m^-1) is

(A) 1×10⁹

(B) 1×10¹¹

(D) 1×10¹⁰

GATE 2020

Answer: (B)

A rigid spherical particle undergoes free settling in a liquid of density 750 kg m^-3 and viscosity 9.81×10^-3 Pa s. Density of the particle is 3000 kg m^-3 and the particle diameter is 2×10^-4 m. Acceleration due to gravity is 9.81 ms^-2. Assuming stokes’ law to be valid, the terminal settling velocity (in m s^-1) of the particle is

(E) 4×10^-3

(F) 3×10^-3

(G) 2×10^-3

(H) 5×10^-3

GATE 2020

Answer: (D)

Consider a cylinder (diameter D and length D), a sphere (diameter D) and a cube (side length D). Which of the following statements concerning the sphericity (ф) of the above objects is true:

GATE 2019

Answer: (A)

A disk turbine is used to stir a liquid in a baffled tank. To design the agitator, experiments are performed in a lab scale model with a turbine diameter of 0.05 m and a turbine impeller speed of 600 rpm. The liquid viscosity is 0.001 Pa s while the liquid density is 1000 kg/m³. The actual application has a turbine diameter of 0.5 m, an impeller speed of 600 rpm, a liquid viscosity of 0.1 Pa s and a liquid density of 1000 kg/m³. The effect to gravity is negligible. If the power required in the lab –scale model is P₁ and the estimated power for the actual application is P₂, then the ratio P₂/P₁ is

(A) 10³

(B) 10⁴

(D) 10⁶

GATE 2019

Answer: (C)

The terminal velocity of spherical particle in gravitational settling under Stokes’ regime varies

(A) Linearly with the particle diameter

(B) Linearly with the viscosity of the liquid

(D) Inversely with the density of particle

GATE 2018

Answer: C

Critical speed of a ball mill depends on

(A) The radius of the mill (shell) and the radius of the particles

(B) The radius of the mill (shell) and the density of the particles

(D) The radius of the balls and the radius of the mill (shell)

GATE 2018

Answer: D

Match the equipment in Column A with the corresponding process in Column B

Column A	Column B
(P) Centrifugal sifter	(I) Mixing
(Q) Ball mill	(II) Sedimentation
(R) Gravity thickener	(III) screening
(S) Two-arm kneader	(IV) Grinding

(A) P-I, Q-IV, R-II, S-III

(B) P-III, Q-IV, R-II, S-I

(D) P-IV, Q-III, R-I, S-II

GATE 2018

Answer: B

In a roll crusher, rolls of diameter 1 m each are set in such a manner that minimum clearance between the crushing surfaces is 15 mm. if the angle of nip is 31°, the maximum diameter of the particle (in mm) which can be crushed is ___________ (rounded off to three decimal places).

GATE 2018

Answer: 53.3

Which of the following is the correct sequence of equipment for size reduction of solids?

GATE 2017

Answer: D

Size analysis was carried out on a sample of gravel. The data for mass fraction (x_i) and average particle diameter (D_pi) of the fraction is given in the table below:

X_i	0.2	0.4	0.4
D_pi (mm)	5	10	20

The mass mean diameter of the sample, to the nearest integer, is _____ mm.

GATE 2017

Answer: 13

In a cyclone separator used for separation of solid particles from a dust laden gas, the separation factor is defined as the ratio of the centrifugal force to the gravitational force acting on the particle. S_r denotes the separation factor at a location (near the wall) that is at a radial distance r from the centre of the cyclone. Which one of the following statements is INCORRECT?

(A) S_r depends on mass of the particle

(B) S_r depends on the acceleration due to gravity

(D) S_r depends on the radial location (r) of the particle

GATE 2016

Answer: (A)

A vertical cylindrical vessel has a layer of kerosene (of density 800 kg/m³) over a layer of water (of density 1000 kg/m³). L -shaped glass tubes are connected to the column 30 cm apart. The interface between the two layers lies between the two points at which the L-tubes are connected. The levels (in cm) to which the liquids rise in the respective tubes are shown in the figure below.

The distance (x in cm, rounded off to the first decimal place) of the interface from the point at which the lower L-tube is connected is _______.

GATE 2016

Answer: 10

A typical batch filtration cycle consists of filtration followed by washing. One such filtration unit operating at constant pressure difference first filters a slurry during which 5 liters of filtrate is collected in 100 s. this is followed by washing, which is done for t_w seconds and uses 1 liter of wash water. Assume the following relation to be applicable between the applied pressure drop ΔP, cake thickness L at time t, and volume of liquid V collected in time t:

ΔP/L = k₁ dV/dt L=k₂V, if L is changing

K₁ and k₂ can be taken to be constant during filtration and washing. The wash time t_w, in seconds (up to one decimal place), is _____________.

GATE 2015

Answer: 40

The diameter of sand particles in a sample range from 50 to 150 microns. The number of particles of diameter x in the sample is proportional to 1/(50+x). The average diameter in microns (up to one decimal place) is _______.

GATE 2015

Answer: 94.3

In order to produce fine solid particles between 5 and 10 µm, the appropriate size reducing equipment is

(A) Fluid energy mill

(B) Hammer mill

(D) smooth roll crusher

GATE 2014

Answer: (A)

Slurries are most conveniently pumped by a

(A) Syringe pump

(B) Diaphragm pump

(D) gear pump

GATE 2014

Answer: (B)

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GATE Chemical Engineering Questions and Answers - Mechanical Operations

2021-08-12T15:29:00.004+05:30

In the Tyler standard screen scale series, when the mesh number increases from 3 mesh to 10 mesh, then

(A) The clear opening decreases

(B) The clear opening increases

(D) The wire diameter increases

GATE 2013

Answer: (A)

Taking the acceleration due to gravity to be 10 m/s², the separation factor of a cyclone 0.5 m in diameter and having a tangential velocity of 20 m/s near the wall is ___________.

GATE 2013

Answer: 160

100 ton/h of a rock feed, of which 80% passed through a mesh size of 2.54 mm, were reduced in size such that 80% of the crushed product passed through a mesh size of 1.27 mm. The power consumption was 100 kW. If 100 ton/h of the same material is similarly crushed from a mesh size of 5.08 mm to a mesh size of 2.54 mm, the power consumption (in kW, to the nearest integer) using Bond’s law, is __________.

GATE 2013

Answer: 70.7 ton/h

The particle size distributions of the feed and collected solids (sampled for same duration) for a gas cyclone are given below.

Size range (µm)	1-5	5-10	10-15	15-20	20-25	25-30
Weight of feed in the size range (g)	2.0	3.0	5.0	6.0	3.0	1.0
Weight of collected solids in the size range (g)	0.1	0.7	3.6	5.5	2.9	1.0

What is the collection efficiency (in PERCENTAGE) of the gas cyclone?

(A) 31

(B) 60

(D) 69

GATE 2011

Answer: (D)

The critical speed (revolutions per unit time) of a ball mill of radius R, which uses balls of radius r, is

GATE 2010

Answer: (D)

The power required for size reduction in crushing is

GATE 2008

Answer: (C)

For laminar flow conditions, the relationship between the pressure drop (ΔP_c) across an incompressible filter cake and the specific surface area (S₀) of the particles being filtered is given by ONE of the following

(A) ΔP_c is proportional to S₀

(B) ΔP_c is proportional to 1/S₀

(D) ΔP_c is proportional to 1/S₀²

GATE 2008

Answer: (C)

Consider the scale-up of a cylindrical baffled vessel configured to have the standard geometry (i.e. height = diameter). In order to maintain an equal rate of mass transfer under turbulent conditions for a Newtonian fluid, the ratio of the agitator speeds should be (given N₁, D₁ are agitator speed and vessel diameter before scale-up; N₂, D₂ are agitator speed and vessel diameter after scale-up)

GATE 2008

Answer: (D)

Two identically sized spherical particles A and B having densities ρ_A and ρ_B respectively, are settling in a fluid of density ρ. Assuming free settling under turbulent flow conditions, the ratio of the terminal settling velocity of particle A to that of particle B is given by

GATE 2008

Answer: (A)

In Tyler series, the ratio of the aperture size of a screen to that of the next smaller screen is

GATE 2007

Answer: (B)

Size reduction of coarse hard solids using a crusher is accomplished by

(A) Attrition

(B) Compression

(D) Impact

GATE 2007

Answer: (B)

In constant pressure filtration, the rate of filtration follows the relation (v: filtrate volume, t: time, k and c: constants).

GATE 2007

Answer: (B)

Sticky materials are transported by

(A) Apron conveyor

(B) Screw conveyor

(D) Hydraulic conveyor

GATE 2007

Answer: (B)

A filtration is conducted at constant pressure to recover solids from dilute slurry. To reduce the time of filtration, the solids concentration in the feed slurry is increased by evaporating half the solvent. If the resistance of the filter medium is negligible, the filtration time will be reduced by a factor of

(A) 1

(B) 2

(D) 8

GATE 2006

Answer: (C)

Common Statement for next two questions

A continuous grinder obeying the Bond crushing law grinds a solid at the rate of 1000 kg/hr from the initial diameter of 10 mm to the final diameter of 1 mm.

If the market now demands particles of size 0.5 mm, the output rate of the grinder (in kg/hr) for the same power input would be reduced to

(A) 227

(B) 474

(D) 856

GATE 2006

Answer: (C)

In order to restore the output back to 1000 kg/hr, an additional grinder was installed. The two grinders can be operated either in series (configuration-1) or parallel (configuration-2). Compare the two configurations in terms of the additional power consumption over the case above.

(A) Configuration-1 consumes less power than configuration-2

(B) Configuration-2 consumes less power than configuration-1

(D) Configuration-2 consumes less or more power than configuration-1 depending on how the feed is distributed between the two grinders in configuration-2 (the parallel configuration)

GATE 2006

Answer: (C)

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GATE Chemical Engineering Questions and Answers - Mechanical Operations

2021-08-11T13:35:00.008+05:30

The critical speed of the ball mill of radius R, which contains balls of radius r, is proportional to

(A) (R-r)^-0.5

(B) (R-r)^-1

(D) (R-r)²

GATE 2005

Answer: (A)

A centrifuge of diameter 0.2 m in a pilot plant rotates at a speed of 50 Hz in order to achieve effective separation. If this centrifuge is scaled up to a diameter of 1 m in the chemical plant, and the same separation factor is to be achieved, what is the rotational speed of the scaled up centrifuge?

(A) 15 Hz

(B) 22.36 Hz

(D) 44.72 Hz

GATE 2005

Answer: (B)

For a cyclone of diameter 0.2 m with a tangential velocity of 15 m/s at the wall. The separation factor is

(A) 2250

(B) 1125

(D) 230

GATE 2004

Answer: (D)

Match the system in Group I with equipment used to separate them in Group II

Group I Group II

P. gas-solid 1. filter press

Q. Liquid-Liquid 2. Cyclone

3. decanter

4. thickner

(A) P – 1, Q – 2

(B) P – 2, Q – 3

(D) P –4, Q – 1

GATE 2004

Answer: (B)

The cumulative mass fractions of particles smaller than size d_j for a collection of N_i particles of diameter d_i and mass m_i (I = 1, 2, 3, ……., ∞) is given by

GATE 2004

Answer: (A)

The Kozney-Carman equation, rewritten in terms of non-dimensional numbers, gives (ΔP/ρu²) proportional to

GATE 2004

Answer: (A)

U_mf is the minimum fluidization velocity for a bed of particles. An increase in the superficial gas velocity from 2U_mf to 2.5U_mf results in (all velocities are smaller than the entertainment velocity of the particles) no change in

(A) Drag on particles

(B) Drag on column walls

(D) The bed voidage

GATE 2004

Answer: (B)

To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of

(A) (1.2)^3/2

(B) (1.2)^3/5

(D) (1.2)^5/3

GATE 2004

Answer: (D)

A centrifugal filtration unit operating at a rotational speed ω has inner surface of the liquid (density ρ_L) located at a radial distance R from the axis of rotation. The thickness of the liquid film is δ and no cake is formed. The initial pressure drop during filtration is

GATE 2004

Answer: (C)

In constant pressure filtration

(A) Resistance decreases with time

(B) Rate of filtration is constant

(D) Rate of filtration decreases with time

GATE 2004

Answer: (D)

Energy requirement (per unit mass of material crushed/ground) is highest for

(A) Jaw crusher

(B) Rod mill

(D) Fluid energy mill

GATE 2003

Answer: (D)

The basic filtration equation is given as

Where, V is volume of the filtrate; A is the filtration area; a is specific cake resistance, μ is viscosity of the filtrate, and C is the concentration of solids in the feed slurry. In a 20 mm. constant rate filtration, 5 m³ of filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes will it take for another 5 m³ of filtrate to be produced? Neglect filter medium resistance, R_m; assume incompressible cake

(A) 10

(B) 20

(D) 30

GATE 2003

Answer: (A)

The power number for a stirred tank becomes constant at high Reynolds number. In this limit, the variation of power input with impeller rotational speed (n) is proportional to

(A) N⁰

(B) N¹

(D) N³

GATE 2001

Answer: D

Energy required per unit mass to grind limestone particles of very large size to 100 µm is 12.7 KWh/Ton. An estimate (using Bond’s law) of the energy to grind the particles from a very large size to 50 µm is

(A) 6.35 KWh/Ton

(B) 9.0 KWh/Ton

(D) 25.4 KWh/Ton

GATE 2001

Answer: C

The volumetric flow rate during constant pressure filtration is given by

dV/dt = 1/(K_cV + Q₀) Where Q₀ = 1/q₀

and V is the total volume of filtrate collected in time t, and K_c and Q₀ are constant

Given V = 1.0 lit at t = 41.3 sec and V = 2.0 lit at t = 108.3 sec. Find K_C.

(A) 26 S/lit²

(B) 28 S/lit²

(D) 32 S/lit²

GATE 2001

Answer: A

A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.4 µm/s. If the Richardson-Zaki index is 4.5, then the terminal settling velocity of sand grain is

(A) 0.9 µm/s

(B) 1 µm/s

(D) 0.02 µm/s

GATE 2000

Answer: A

For a sphere falling in a constant drag coefficient regime, its terminal velocity depends on its diameter ‘d’ as

(A) d

(B) d^0.5

(D) 1/d

GATE 2000

Answer: B

During washing of filter at the end of constant pressure filtration, the rate of washing equals the

(A) Rate of filtration at time zero

(B) Rate of filtration at the end of filtration

(D) Rate of filtration at the end of filtration but decreases with time subsequently

GATE 1999

Answer: B

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Conference/Seminar/Workshop/FDP/STTP/Certificate Course/Special Lecture

2021-08-10T21:42:00.008+05:30

Event: One-Week Virtual Short term Training Program on “Computational Fluid Dynamics: Part-II (Intermediate Level)”

Type of Event: Short term Training Program

Date: 16.08.2021 – 20.08.2021

Organized by: Department of Mechanical Engineering, S.V. National Institute of Technology Surat, 395 007 Gujarat, India

Eligibility: Under Graduate, Post Graduate and PhD Students, Faculty of Engineering, Engineers & Scientists from Industry.

Course Contents: through CFD, Higher order schemes to Finite Difference Method, Coupled heat transfer using DOMFVM, Multiphase Flow Modeling, Lattice Boltzmann Method, Meshless Technique applied to Bioheat Transfer, Inverse methods to heat transfer problem, Transport in porous media, Combustion modeling, Demonstration on ANSYS-Fluent and/or OPEN- FOAM and/or Code Development

Registration Deadline: 13.08.2021

Registration Fee: UG, PG, Research Scholars ₹ 500/-, Faculty ₹ 1000/, Industry Delegate ₹ 2000/.

For Details Click on: Brochure

Event: Short-Term Training Course on “X-ray Diffraction: Theory, Methods and Workflow (XRD 2021)”

Type of Event: Short-Term Training Course

Date: 06.09.2021 – 15.09.2021

Organized by: Department of Materials and Metallurgical Engineering in collaboration with Department of Physics Maulana Azad National Institute of Technology Bhopal – 462003

Eligibility: Undergraduate and postgraduate students of science and engineering discipline looking for certified courses, Research scholars looking for interpreting their xrd data Analysts, Technicians looking for refresher course, Lab managers who are responsible for the instrument or generating data in production line Teaching, faculty who are handling this course Researchers.

Course Contents: Basics of X-Ray Powder Diffraction, Principal and crystallography History of X-rays. Diffractometer: Theory and Instrumental Details (Tube design, Goniometer, Detector, sample holder) Demonstration of Equipments Sample preparation: Powders (grain size effects, packing/preferred orientation, sample height and width) Thin-films, Capillary/fibers, Single crystal and biological samples Data collection, optimization of scan parameters, scan optimization, Profile Fitting for Quantitative Analysis, Acquisition of pattern, Peak indexing, Phase identification Scherrer Equation, Williamson Hall Plot, Calculation of Crystallite size and Lattice strain X-ray Technique for Thin film Study and Fundamentals of Rietveld Refinement XRD Simulation

Registration Deadline: 30.08.2021

Registration Fee: Rs 500/- for students and Rs 1000/- for teaching faculties, researchers and Industrialist.

For Details Click on: Brochure

Event: Short term Course on “Project Land Acquisition, Environmental Clearance, CSR and Industrial Regulations”

Type of Event: Short Term Course

Date: 07.12.2021 – 11.12.2021

Organized by: Department of Mining Engineering Indian Institute of Technology, Kharagpur, India

Eligibility: All the executives of Public and Private industries, Department of State, and Central ministry, Public Utilities, Core Industry, Mining, Oil and Gas, PWD, Railway, Aviation, Port, Roads, Power, Highway Authority, DM’s Office, Banks and other officers as appropriate.

Course Contents: Basics of environmental Management. Understanding of Indian Land and RFCTLARR ‘2013. Environmental Clearance Act Rules 2006 Notifications and Circulars. Forest Rights Act and Diversion of Forest Land for Various Purposes. Roles of Administrators. Defense for Clearance. Compensation Design for Long-term Results. Environmental Clearance Regulations. Environmental Impact Assessment Criteria & Checklist. Public Hearing & Corporate Social Responsibility. Strategic CSR Management. Recant Industrial Regulations: Facility Act, Contract Labour Act, MMDR Act etc.

Registration Deadline: Not mentioned

Registration Fee: Rs.21,000.00 per participant + GST@18% Will have to be paid as per GOI rules..

For Details Click on: Brochure

Event: 2^nd International Conference on Chemical, Bio & Environmental Engineering (CHEMBIOEN-2021)

Type of Event: International Conference

Date: 20.08.2021-22.08.2021

Organized by: Department of Chemical Engineering, Dr B R Ambedkar National Institute of Technology, Jalandhar, Punjab-144011, India

Themes: Advance Oxidation Processes, Bio-chemical Engineering, Chemical Reaction Engineering, Computational Fluid Dynamics, Downstream Processing, Environment Impact Assessment, Environment Management, Fluidization, Fluid Flow, Green Technologies, Chemical Engineering, Environmental Engineering, Biochemistry, Genetic & Protein Engineering, Fuel and Energy, Heat and Mass Transfer, Material Science & Engineering, Modeling and Simulation, Nanotechnology, Process Control, Pollution Monitoring, New and Renewable Energy, Separation Processes, Solar Cells, Water and Air Treatment, Nanobiotechnology, Pharmaceutical Biotechnology, Any other related topic.

Abstract Submission Deadline: Extended date 12.08/2021

Full Paper Publication Process: Date extended

Registration Deadline: Date extended

Registration Fee: Indian delegates (Faculty, scientists, Research Scholar, students) Rs. 2000/-

Foreign Delegates USD 50

For Details Click on: Brochure

Event: Online Faculty Development Programme (e-FDP) on “Additive Manufacturing: Programming, Operation & Applications (AMPOA-21)”

Type of Event: Faculty Development Programme

Date: 20.09.2021 – 24.09.2021

Organized by: Department of Industrial & Production Engineering Dr. B R Ambedkar National Institute of Technology, Jalandhar, India

Eligibility: Not mentioned.

Course Contents: Additive Manufacturing: Programming, Operation & Applications.

Registration Deadline: Not mentioned

Registration Fee: There is No Registration Fee.

For Details Click on: Brochure

Event: International Webinar on “Rubber Products for a Green Future: Recycling & Sustainability (RPGF 2021)”

Type of Event: International Webinar

Date: 02.09.2021

Organized by: Indian Institute of Technology, Kharagpur, India

Key Topics: Thermoplastic elastomers: process, properties and recent applications

Natural rubber based nanocomposites

Silica filled rubber compounding ingredients for natural rubber

Block co-polymers with complex architectures

Characterization of Rubber nanocomposites via SAXS

Eligibility: Not mentioned.

Registration Deadline: Not mentioned

Registration Fee: There is No Registration Fee.

For Details Click on: Brochure

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Conference/Seminar/Workshop/FDP/STTP/Certificate Course/Special Lecture

2021-08-03T21:30:00.003+05:30

Event: Internet Course – Environmental Management (EM 2021)

Type of Event: Internet Course

Date: 04.09.2021 – 08.12.2021

Organized by: Indian Institute of Science (IISc), Bengaluru.

Themes: Principles of Environmental Management. Principles of Ecology, Environment & Environmental Management. Municipal Solid Waste Management – Principle and case studies. Policies and Legal Aspect of Environmental Management. Overview of Environmental Impact Assessment (EIA); Preparation and Review of Environmental Impact Assessment Report. Environmental Audit. Life Cycle Assessment as EM Tool. Environmental Management Systems Standards: ISO 14000 (EMS). Environmental Design. Environmental Economics. Application of Geoinformatics (Geographic Information System (GIS) and Remote Sensing) in Environmental Management. Carrying capacity assessment.

Application Submission Deadline: 05.08.2021

Registration Deadline: 05.08.2021

Confirmation Deadline: 15.08.2021

Registration Fee: Rs 20000 + 18% GST for participants nominated from academic institutions and government agencies

Rs. 18000+18% GST for ISTE Members with work experience of 5 years as teaching faculty and nominated from academic institutions.

Rs. 10000+18% GST for PG students and weaker sections (including SCs/STs – include certificate), unemployed FRESH graduates (graduated after 2018).

Rs.28,000+18% GST for participants from industries and independent consultants

For Details Click on: Brochure

Event: A National Conference on “Sustainable Environment: Challenges and Opportunities”

Type of Event: National Conference

Date: 08.09.2021 - 09.09.2021

Organized by: Center for Continuing Education, Dr B R Ambedkhar National Institute Technology, Jalandhar.

Themes: Global Environmental Changes; Environmental Disasters and Hazards; Loss of Biodiversity; Pollution: Decreasing Air, Water and Noise Quality; Population and Environment; Environment and Health; Environment and Education; Water Scarcity and Shortage; Lack of Waste Management; World Food Problems including Food Wastage and Hunger; Desertification; Soil exploitation.

Abstract Submission Deadline: 05.08.2021

Date of Notification of Abstract Acceptance: 10.08.2021

Registration Deadline: 20.08.2021

Registration Fee: Faculty/Scientists Rs. 1000; Research Scholars Rs. 600; UG/PG Students Rs. 300

For Details Click on: Brochure

Event: 2^nd International Conference on Chemical, Bio & Environmental Engineering (CHEMBIOEN-2021)

Type of Event: International Conference

Date: 20.08.2021-22.08.2021

Organized by: Department of Chemical Engineering, Dr B R Ambedkhar National Institute Technology, Jalandhar, India.

Themes: Advance Oxidation Processes; Bio-chemical Engineering; Chemical Reaction Engineering; Computational Fluid Dynamics; Downstream Processing; Environment Impact Assessment; Environment Management; Fluidization; Fluid Flow; Green Technologies; Chemical Engineering; Environmental Engineering; Biochemistry; Genetic & Protein Engineering; Fuel and Energy; Heat and Mass Transfer; Material Science & Engineering; Modeling and Simulation; Nanotechnology; Process Control; Pollution Monitoring; New and Renewable Energy; Separation Processes; Solar Cells; Water and Air Treatment; Nanobiotechnology; Pharmaceutical Biotechnology; Any other related topic.

Extended Abstract Submission Deadline:

Date of Notification of Abstract Acceptance:

Full Paper submission Deadline:

Registration Deadline:

Registration Fee: Category I:

Indian Delegates (Faculty, Scientists, Research Scholars, Students) Rs. 2000/- Foreign Delegates USD 50

Category II:

Indian Delegates (Faculty, Scientists, Research Scholars, Students) Rs. 1000/-

For Details Click on: Brochure

Event: 2nd National and 1st International conference on Advances in Fluid Flow and Thermal Sciences

Type of Event: International conference

Date: 24.09.2021 – 25.09.2021

Organized by: Department of Mechanical Engineering SVNIT-Surat, Gujarat, India

Themes: Mini/Micro/Nanoscale Flow and Heat Transfer Multiphase Flow and Heat Transfer. Flow Instability and Turbulence. Porous Media, Radiation, Inverse. and Bio Heat Transfer Computational Methods. Combustion, Fire and Fuels. Refrigeration and Cryogenics. Flow Visualization, Measurement. Instrumentation Application of AI in Flow and. Heat Transfer Thermal management of Electronics systems. Flow and Heat Transfer in Advanced Applications. Thermo-economic Analysis of. Energy Systems.

Extended Abstract Submission Deadline:

Date of Notification of Abstract Acceptance:

Full Paper submission Deadline:

Registration Deadline: 30.08.2021

Registration Fee: Students/ Research Scholars: INR 3000/-

Academic Institutions: INR 7500/-

For Details Click on: Brochure

Event: 7^th National and 1^st International Conference on Refrigeration and Air Conditioning (NCRAC 2022)

Type of Event: International Workshop

Date: 24.02.2022-26.02.2022

Organized by: Indian Institute of Technology Guwahati & Indian Institute of Technology Tirupati, In association with Indian Society of Heating Refrigerating and Air Conditioning Engineers (ISHRAE), India

Themes: Energy efficiency and cold/heat recovery, Novel/alternate ecofriendly RAC systems, Natural/new refrigerants and mixtures, Refrigerated cold chain, transport and cold stores, Food cold storage and refrigerated transport, Sorption heating and cooling systems, District heating and cooling, Desiccant and evaporative cooling, Polygeneration, Indoor air quality and Industrial ventilation, Green buildings, Modern innovations in HVAC systems, Low temperature applications, Building services and automations, Materials for energy conversion systems, Thermodynamic cycles, Thermal comfort and comfort standards, Thermal energy storage, Materials and HMT in HVAC &R.

Full Paper submission Deadline: 01.11.2021

Registration Deadline:

Registration Fee: Per delegate it is Rs. 6,000/-

For student authors from academic institutes and research labs is Rs. 4,000/-. The registration fee for industry participants is Rs. 10,000/-

For Details Click on: Brochure

Event: One Week AICTE Training and Learning (ATAL) Academy Sponsored Online Faculty Development Program On “Design Thinking and Product Development”

Type of Event: FDP

Date: 23.08.2021-27.08.2021

Organized by: The Department of Mechanical Engineering National Institute of Technology Arunachal Pradesh, India.

Themes: Three phases of Design Thinking as such Inspire, Ideate and Implement and thus improve the product development process. The course will also emphasize on the use of practical design thinking methods and tools used in every stage of new product development phase and adopt new attitudes about new product development and customer problem solving.

Eligibility: The program is open to members of faculty of various engineering disciplines, PG and Ph.D. research scholars, startup entrepreneurs, employees, professionals, managers and leaders involved in designing products or services, scientists and professionals from R&D organizations, industries, govt. bodies.

Registration Deadline: Not mentioned

Registration Fee: Nil

For Details Click on: Brochure

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Chemical Engineering Textbooks

2021-05-10T09:18:00.001+05:30

Fluid Mechanics:

1. A Text Book of Fluid Mechanics and Hydraulic Machines, by Dr. R. K. Bansal

2. Fluid Mechanic, by L. D. Landau and E. M. Lifshitz

3. Fluid Mechanics, by Joseph H. Spurk, and Nuri Aksel

4. Fluid Mechanics for Chemical Engineering, by Noel de Nevers

5. Unit Operations of Chemical Engineering, by Warren L. McCabe, Julian C. Smith, Peter Harriott

6. Chemical Engineering Fluid Mechanics, by Ron Darby

7. Fluid Mechanics, by Kreith, F and Berger, S.A.

8. Fluid Mechanics, by Pijush K. Kundu, Ira M. Cohen

Heat Transfer:

1. Heat Transfer: A Practical Approach, by Yunus A. Cengel

2. Heat Transfer, by J.P. Holman

3. Engineering Heat Transfer, by Dr. William S. Janna

4. Process Heat Transfer, by Donald Q. Kern

Mechanical operation:

1. Unit Operations in Chemical Engineering, McGraw-Hill, Fourth Edition, 1984, by McCabe, W.L, Smith J.C and Harriot, P.

2. Chemical Engineering, Volume 2, Third Edition, Pergamon Press, 1977, by Coulson, J.M., Richardson, J.F.

3. Introduction to Chemical Engineering, TMH, by Badger and Bencharo.

Mass Transfer:

1. Principles of Mass Transfer and Separation Processes, by Binay K. Dutta

2. Mass-Transfer Operations, by Robert E. Treybal

3. Mass Transfer in Chemical Engineering Processes, Edited by Jozef Markoš

4. Fundamentals of heat and mass transfer, by Incropera/Dewitt/Bergman/Lavine

5. Heat and Mass Transfer, by Kreith, F. Boehm, R.F.

6. Hydrodynamics, Mass and heat transfer in Chemical Engineering, by A.D. Polyanin, A.M. Kutepov, A. V. Vyazmin and D. A. Kazenin

Chemical Reaction Engineering:

1. Chemical Reaction Engineering, by Octave Levenspiel

2. Elements of Chemical Reaction Engineering, by H. Scott Fogler

3. Introduction to Chemical Reaction Engineering and Kinetics, By Ronald W. Missen Charles A. Mims Bradley A. Saville

4. The Engineering of Chemical Reactions, by Lanny D. Schmidt

Thermodynamics:

1. Introduction to Chemical Engineering Thermodynamics, By J.M. Smith, H.C. Van Ness, M.M. Abbott

2. Engineering Thermodynamics, By R.K. Rajput

3. Chemical Thermodynamics of Materials, by Svein Stølen, Tor Grande, Neil L. Allan

4. Thermodynamics An Engineering Approach, by Yunus A. Cengel, Michael A. Boles

5. Thermodynamics of systems containing flexible-chain polymers by Vitaly J. Klenin

Chemical Process Calculations (Stoichiometry):

1. Chemical Process Principles, by Olaf A. Hougen and Kenneth M. Watson

2. Basic Principles and Calculations in Chemical Engineering, by David M. Himmelblau James B. Riggs

Chemical Process Technology:

1. Outlines of Chemical Technology Affiliated East West Press Dryden, C. E., and Rao, M.G. (Ed.).

2. Sherve’s Chemical Process Industries, MGH 5th Edn, Austins, G.T.

Process Control:

1. Essentials of Process Control, by Michael L. Luyben and William L. Luyben

2. Process control systems, by F. G. Shinskey

3. Chemical Process Control and Chemical Modeling, by Stephanopulos

4. Process systems analysis and control, by Donald R. Coughanowr

Transport Phenomena:

1. Transport Phenomena, by Bird, Stewart, Lightfoot

2. Thermodynamic and Transport Properties of Fluids, by G. F. C. Rogers and Y. R. Mayhew

3. Transport Processes and Unit Operations, by Christie J. Geankoplis

4. Transport Phenomena and Unit Operations, by Richard G. Griskey

Plant Design and Economics:

1. Plant Design and Economics for Chemical Engineers, by Max S. Peters Klaus D. Timmerhaus

2. Preliminary Chemical Engineering Plant Design, by William D. Baasel

Modelling, Simulation and Optimization:

1. Process Plant Simulation, by B.V. Babu

2. Process Modeling, Simulation, and Control for Chemical Engineers, by William L. Luyben

3. Modeling of Chemical Kinetics and Reactor Design, by A. Kayode Coker

4. Integrated Design and Simulation of Chemical Processes, by Alexandre C. Dimian

Energy Technology:

1. Fuels & Combustion, by Dr. Samir Sarkar,Orient Longmans

2. Elements of Fuels. Furnace and Refractories, by O.P .Gupta

Conference/Seminar/Workshop/FDP/STTP/Certificate Course/Special Lecture

2021-03-26T23:51:00.008+05:30

Event: National e-Conference on “RECENT TRENDS IN FLUID DYNAMICS RESEARCH (RTFDR-21)”

Type of Event: National Conference

Date: 02.04.2021-04.04.2021

Organized by: Department of Chemical Engineering National Institute of Technology Rourkela, Rourkela.

Themes: Fluid Mechanics and Applications, Microfluidics and Nanofluidics, Numerical Methods for Multiphase Flows, Cavitation, Combustion, Fluid-Particle Interactions in Turbulence, Biological Flows, CFD, Experimental Fluid mechanics, Convection heat transfer, Numerical heat transfer, Fluid power, Experimental heat transfer, Fluidization, Non-Newtonian rheology, Boundary layer theory.

Abstract Submission Deadline: Abstract submission date 28/03/2021

Full Paper Publication Process: 05.05.2021 Onwards

Registration Deadline: 29.03.2021

Registration Fee: Category –I (ABSTRACT ONLY)

INR 500: FOR ALL

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Event: INTERNATIONAL CONFERENCE on “Recent Development on Materials, Reliability, Safety and Environmental Issues”

Type of Event: International Conference

Date: 25.06.2021 - 27.06.2021

Organized by: Department of Chemical Engineering, Department of Electronics & Communication Engineering, Department of Industrial & Production Engineering, Dr B R Ambedkhar National Institute Technology, Jalandhar.

Themes: Solid Waste Management, E Waste Management, Water and wastewater treatment, Air Pollution, Risk Assessment, Membrane Separation Processes, Advance Oxidation Processes, Biodegradable polymers, Sustainable development, Nanomaterials, Biopolymers Green technology, Biofuels Ion exchange, adsorption Economic analysis Nanofiltration Innovations in pollution abatement VLSI Circuit Design Nanoelectronics MEMS Technology Microelectronics & Nanotechnology, Electronics Communication RF & Antenna Design Electronics System Design FPGA/ASIC Based Design Internet of Things Machine Learning Solar/PV cell Design Materials, Synthesis & Characterization Flexible Devices Organic Electronics Nano & Bio Sensors Safety & Loss prevention Security Risk Assessment Inherent Safer Processes Bhopal Gas Tragedy & its effects on safety, Reliability, Vulnerability assessment Reliability modeling & Evaluation RAMS Analysis FMECA Fault tolerant Systems Maintenance Strategies Reliability Evaluation using Simulation Nets Application of Soft Computing Techniques

Abstract Submission Deadline: 10.05.2021

Date of Notification of Abstract Acceptance: 20.05.2021

Full Paper submission Deadline: 10.05.2021

Submission of Camera ready paper: 31.05.2021

Registration Deadline: 31.05.2021

Registration Fee: Online:

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Category I - Rs. 1500, Category II – Rs. 2500, Category III – Rs. 3000

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Category I - 100 USD, Category II - 200 USD, Category III - 250 USD

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Event: Eighth International Conference on “Theoretical, Applied, Computational and Experimental Mechanics (ICTACEM)”

Type of Event: International Conference

Date: 20.12.2021-22.12.2021

Organized by: Department of Aerospace Engineering, Indian Institute of Technology Kharagpur, India.

Themes: Fluid mechanics, Solid mechanics and Dynamics, Flight mechanics, Control and Navigation, Propulsion and Combustion

Extended Abstract Submission Deadline: 01.04.2021

Date of Notification of Abstract Acceptance: 31.07.2021

Full Paper submission Deadline: 30.09.2021

Registration Deadline: 31/10/2021

Registration Fee: Delegates from SAARC Countries:

Before 31.10.2021:

Educational Institutions Rs. 8000

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Educational Institutions Rs. 10000

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Educational/research Institutes US$ 450

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Event: Five days Online Training on “Safety Engineering in Mines for Augmenting Safety Management”

Type of Event: Short Term Course

Date: 04.05.2021 – 08.05.2021

Organized by: Organized by the Department of Mining Engineering, Indian Institute of Technology Kharagpur, India

Eligibility: Not mentioned.

Course Contents: Industry 4.0: Challenges and opportunities, Root cause analysis of safety deterioration, Assessment of wellness of engineering systems, Mechatronics for understanding system performance, Slope Stability Radars (SSR)- Practical application in mines for monitoring of slope failures, VISION ZERO: from concept to realization in mining industry.

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Event: National Workshop on “Air Pollution and Health Hazards (APHH-2021)”

Type of Event: National Workshop

Date: 31.03.2021

Organized by: Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, Punjab and Punjab Pollution Control Board, Punjab State Government, Punjab, India

Eligibility: Administrative Officers, Industry Professionals, Academicians, Medical professionals, and other Stake Holders.

Course Contents: To create awareness amongst the participants regarding policies, guidelines, standards w.r.t. air quality for healthy life forms. To apprise the participants to polluted air, its sources, Health hazards and control measures for air pollution. The role of various stakeholders in controlling the air pollution. Current impact of air pollution and human lifestyle on present COVID-19 pandemic.

Registration Deadline: 30.03.2021

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Chemical Engineering Jobs

2021-03-25T15:58:00.004+05:30

Name of the Post: Deputy Secretary (Food Processing)

Organization: Ministry of Food Processing Industries

Essential Qualification: B.E./B.Tech in Food Technology/ Food Engineering/ Agricultural Engineering/ Chemical Engineering Or Bachelor’s Degree in Biotechnology/ Dairying/ Fisheries/ Animal Husbandry from a recognized University/ Institution.

Desirable Qualification: Master’s Degree from a recognized University/ Institution in the related fields.

No. of Posts: One

Experience required (in years): Ten years’ experience in Food Processing Industry/Sector

Employment type: Permanent

Salary: Pay Level-12 in the Pay Matrix as per 7th CPC

Category: Govt. Jobs

Mode of Selection: Interview

Application Fee: Nil

Last date of Application: Online Application 03.05.2021

Date of Interview/Exam: Not Mentioned

For details click on: Advertisement

Name of the Post: Research Associate (Postdoctoral Fellow)

Organization: Indian Institute of Technology Gandhinagar

Essential Qualification: Ph.D. (graduated or submitted Thesis) in Chemical Engineering/Physics/Computer Science/Chemistry/Mathematics/Mechanical Engineering/Material Science.

Desirable Qualification: The applicant should have expertise in developing the MCMC-based algorithms, or applying them in their research projects. The applicant should be proficient in computer programming and should be experienced in performing simulations/calculations using high performance computing (HPC) systems. The experience in developing applications for HPC systems is desirable.

No. of Posts: not mentioned

Experience required (in years): ₹ 47,000 to 50,000 based on qualifications/experience

Employment type: Temporary [one year (Extendable to additional 1 year)]

Salary: ₹ 47,000 to 50,000 based on qualifications/experience

Category: Govt. Jobs

Mode of Selection: Online interview

Application Fee: Nil

Last date of Application: Not mentioned

Date of Interview/Exam: Not mentioned

For details click on: Advertisement

Name of the Post: Senior Research Fellows

Organization: Indian Institute of Technology Guwahati

Essential Qualification: M Tech in Chemical Engineering/Biotechnology

Desirable Qualification: Research experience in Biopolymer extraction and modification/biodegradable Polymers/Migration Studies/polymer Coating

No. of Posts: Two

Experience required (in years): Two Years

Employment type: Temporary (11 months)

Salary: Rs. 35000 + HRA 5,600/-

Category: Govt. Jobs

Mode of Selection: Online Interview

Application Fee: Nil

Last date of Application: 25.03.2021

Date of Interview/Exam: on 30.03.2021

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Name of the Post: Postdoctoral Fellow

Organization: ICT-IOC Odisha Campus, Bhubaneswar

Essential Qualification: PhD in Chemical Engineering/ Chemistry/Physics, Candidate who have submitted thesis and awaiting for degree is also eligible to apply

Desirable Qualification: Not mentioned

No. of Posts: 05

Experience required (in years): Not mentioned

Employment type: Temporary (up to two years depending upon performance)

Salary: Rs. 50,000/- per month

Category: Govt. Jobs

Mode of Selection: Interview

Application Fee: Nil

Last date of Application: 30.03.2021

Date of Interview/Exam: Not mentioned

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Name of the Post: Project Fellow

Organization: Institute of Chemical Technology, Mumbai

Essential Qualification: Master’s degree in Chemistry/Physics/Chemical Engineering/Material Science.

Desirable Qualification: Not mentioned

No. of Posts: One

Experience required (in years): Not mentioned

Employment type: Temporary (Two years)

Salary:Rs. 20,000/- pm

Category: Govt. Jobs

Mode of Selection: Interview

Application Fee: Nil

Last date of Application: 26.03.2021

Date of Interview/Exam: 30.03.2021

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GATE Chemical Engineering Questions and Answers – Project Engineering

2021-03-08T21:18:00.008+05:30

The end of a cylindrical vessel can be closed by a head, which can be one of the four shapes. For the same thickness, choose the one which can withstand the highest pressure.

(A) Flat plate

(B) Hemispherical

(D) Ellipsoidal

GATE 2001

Answer: (B)

P is the investment made on an equipment, S is its salvage value and n is the life of the equipment in years. The depreciation for m^th year by the sum of years-digits method will be

(A) (P - S)/n

(B) 1 - (P/S)^1/m

(D) 2(n – m + 1)(P - S)/n(m + 1)

GATE 2001

Answer: (D)

An investment of Rs. 1000 is carrying an interest of 10% compounded quarterly. The value of the investment at the end of five years will be

(A) 1000(1+0.1/4)²⁰

(B) 1000(1+0.2)²⁰

(D) 1000(1+0.1/2)⁵

GATE 2001

Answer: (A)

For a cylindrical internally pressurized vessel which of the following closure types would withstand highest pressure if each closure is of the same material and thickness?

(A) Hemispherical

(B) Ellipsoidal

(D) Flat plate

GATE 1998

Answer: (A)

For a gas cylinder designed on the “thin cylinder principle” calculate the thickness of a seamless cylinder under the following conditions.

Pressure of N₂ gas in the cylinder = 100×10⁵ N/m²

Tensile stress permissible = 1200×10⁵ N/m²

Internal diameter of the cylinder = 25 cm

(A) 10.4 mm

(B) 11.5 mm

(D) 13.5 mm

GATE 1992

Answer: (A)

The plant of a chemical company has an initial worth of Rs. 50 lakhs and an estimated exchange value of Rs. 2 lakhs in service life of 8 years. Estimate the book value of the plant at the end of 4 years for straight line method of depreciation?

(A) Rs. 24 lakhs

(B) Rs. 26 lakhs

(D) Rs. 30 lakhs

GATE 1992

Answer: (B)

The cost of a blower in 1980 is Rs. 2000. What is the cost of the blower in 1988 with the same capacity? The cost index for the blower in 1980 and 1988 are respectively 250 and 300.

(A) Rs. 1800

(B) Rs. 2100

(D) Rs. 2600

GATE 1992

Answer: (C)

A reactor having a salvage value of Rs 10,000 is estimated to have a service life of 10 years. The annual interest rate is 10%. The original cost of the reactor was Rs. 80,000. The book value of the reactor after 5 years will be

(A) Rs. 40,000

(B) Rs. 45,000

(D) Rs. 52,000

GATE 1991

Answer: (B)

In the manufacturing industry breakeven point occurs when

(A) The annual rate of production equals the assigned value

(B) The total annual product cost equals the total annual sales

(D) The annual sales equals the fixed costs

GATE 1991

Answer: (B)

A standard type of heat exchanger with a negligible scrap costs Rs. 40000 and will have a useful life 6 years. Assuming an effective compound interest of 10% per year, the capitalized cost of a heat exchanger will be

(A) Rs. 60880

(B) Rs. 90880

(D) Rs. 81880

GATE 1991

Answer: (C)

The total capital investment for a chemical plant is Rs. 1000000 and the working capital is Rs. 100000. If a turnover ratio is 1 the gross annual sales will be

(A) Rs. 800000

(B) Rs. 900000

(D) Rs. 1100000

GATE 1991

Answer: (B)

A heat exchanger with an initial investment of Rs. 300000 has a 6 years life. How much can be spent on an improved design which has a life of 12 years and is expected to save Rs. 10000 per year? Annual compounded interest rate is 8%.

(A) Rs. 232232

(B) Rs. 261400

(D) Rs. 352340

GATE 1991

Answer: (B)

A spherical storage tank is having an outer diameter of 2 m and a thickness of 5 mm. The tank seems are welded and having joint efficiency of 0.85. The material of construction will be plain carbon steel. The chemical will be stored at maximum temperature of 298 K. No corrosion problems are expected. What maximum internal pressure the tank will withstand safely. Allowable design stress value at working temperature = 118 MN/m².

(A) 1.003 Mn/m²

(B) 1.05 Mn/m²

(D) 2.68 MN/m²

GATE 1991

Answer: (A)

For a project having a life of ten years the following cash flow pattern is expected:

End of year

Net cash flow

1 - 10

-5000000

2000000

-15000000

If the expected interest rate is 2% what is your recommendation about implementing the project

(A) May be recommended for implementation

(B) May not be recommended for implementation

(D) None of these

GATE 1990

Answer: (A)

The annual production costs for a plant are Rs. 36.4 lakhs while the sum of annual fixed charges, overhead costs and general expenses are Rs. 26.0 lakhs. What is the breakeven point in units of production per year if the total annual sales are 72.8 lakhs and the product sells at Rs. 520 per unit.

(A) 1000

(B) 1500

(D) 15000

GATE 1989

Answer: (C)

For a 1-1 fixed tube sheet heat exchanger the following data are given

Design inside pressure: shell side 10³ KN/m²

Tube side 2×10³ KN/m²

Design temperature shell side 50°C

Tube side 150°C

Allowable stress value at both design temperature is 1.2×10⁵ KN/m². Shell inside dia = 0.6 m, corrosion allowance is 3×10^-3 m and joint efficiency = 1. What is the shell thickness?

(A) 5.50×10³ m

(B) 6.5×10³ m

(D) 8.5×10³ m

GATE 1990

Answer: (A)

A bond matures after5 years and has a maturity value of Rs. 1000. If the interest rate is 12%, what is the present worth of the bond?

(A) Rs. 568

(B) Rs. 575

(D) Rs. 590

GATE 1988

Answer: (A)

Cylindrical shell A closed at the ends have been provided with 3 circumferential ring stiffeners. Shell B is identical to A but is provided with 6 circumferential stiffeners. Which vessel can withstand more internal pressure.

(A) A

(B) B

(D) Same pressure in both

GATE 1988

Answer: (B)

A heat exchanger of area 10 m² costed Rs.50000 in 1985. What is the estimated cost of a 15 m² exchanger in 1987. Assume that the cost index in 1985 was 270 and in 1987 is 320.

(A) Rs. 70250

(B) Rs. 75580

(D) Rs. 87750

GATE 1988

Answer: (B)

A plant is producing 1000 tons per year of a product. The overall yield is 70% on mass basis. The raw material costs Rs. 100/ton and the product sells at Rs. 350 per ton. A process modification has been devised that will increase the yield to 75%. The additional investment required is Rs. 400000. What is the rate of return for the additional investment made?

(A) 3.5%

(B) 4.5%

(D) 6.5%

GATE 1987

Answer: (B)

GATE Chemical Engineering Questions and Answers – Chemical Reaction Engineering

2021-03-01T21:21:00.011+05:30

For the liquid phase zero order reaction A → B, the conversion of A in a CSTR is found to be 0.3 at a space velocity of 0.1 min. What will be the conversion for a PFR with a space velocity of 0.2 min^-1. Assume that all the other operating conditions are same for CSTR and PFR.

(A) 0.15

(B) 0.25

(D) 0.45

GATE 1999

Answer: (A)

Consider the nth order irreversible liquid phase reaction A → B. Which one of the following plots involving half-life of the reaction (t^1/2) and the initial reactant concentration (C_A0) gives a straight line plot?

(A) C_A0 vs t_1/2

(B) lnC_A0 vs t_1/2

(D) lnC_A0 vs lnt_1/2

GATE 1999

Answer: (D)

At a given value of E/R (ratio of activation energy and gas constant), the ratio of the rate constant at 500 K and 400 K is 2 if Arrhenius law is used. What will be this ratio if transition state theory is used with the same value of E/R?

(A) 1.6

(B) 2

(D) 2.5

GATE 1999

Answer: (D)

For the reaction A + B → 2B + C

(A) r_A = r_B

(B) r_A = -r_B

(D) r_A = r_B/2

GATE 1999

Answer: (B)

Overall order of reaction for which the rate constant has units of (mol/lit)^-3/2 is

(A) -3/2

(B) ½

(D) 5/2

GATE 1999

Answer: (D)

For the reaction P + 2Q → 3R, molar rate of consumption of P is

(A) double of that of Q

(B) same as that of Q

(D) 2/3 of that of Q

GATE 1998

Answer: (C)

Molecularity of an elementary reaction

P + Q → R + S is

(A) 1

(B) 2

(D) 4

GATE 1998

Answer: (B)

For a given duty and for all positive reaction orders, the size of a mixed reactor is

(A) Smaller than that of a plug flow reactor

(B) Same as that of a plug flow reactor

(D) None of the above

GATE 1998

Answer: (C)

A reversible liquid phase endothermic reactions is to be carried out in a plug flow reactor. For minimum reactor volume it should be operated such that the temperature along the length

(A) Decreases

(B) Increases

(D) First increases and then decreases

GATE 1997

Answer: (C)

The gas phase reaction 2A → B is carried out in an isothermal plug flow reactor. The feed consists of 80 mole% A and 20 mole% inerts. If the conversion of A at the reactor exit is 50%, then C_A/C_A0 at the outlet of the reactor is

(A) 2/3

(B) 5/8

(D) 3/8

GATE 1997

Answer: (B)

For first order isothermal chemical reaction in a porous catalyst, the effectiveness factor is 0.3. The effectiveness factor will increase if the

(A) Catalyst size is reduced or the catalyst diffusivity is reduced

(B) Catalyst size is reduced or the catalyst diffusivity is increased

(D) Catalyst size is increased or the catalyst diffusivity is increased

GATE 1997

Answer: (B)

From Collision theory, the reaction rate constant is proportional to

GATE 1996

Answer: (D)

The Kundsen diffusivity is dependent on

(A) The molecular velocity only

(B) The pore radius of the catalysis only

(D) The molecular velocity and pore radius of the catalysts

GATE 1996

Answer: (D)

For a first order chemical reaction in a porous catalyst, the Thiele modulus is 10. The effectiveness factor is approximately equal to

(A) 1

(B) 0.5

(D) 0

GATE 1996

Answer: (C)

When an exothermic reversible reaction is conducted adiabatically the rate of reaction

(A) Continuously increases

(B) Continuously decreases

(D) Passes through a minimum

GATE 1996

Answer: (C)

The energy balance equation over a tubular reactor under transient conditions is

(A) An ordinary non-linear differential equation

(B) An algebraic equation

(D) A non-linear partial differential equation

GATE 1996

Answer: (D)

For a mixed flow reactor operating at steady state, the rate of reaction is given by

(A) F_A0/V-dC_A/dt

(B) F_A0/V + dC_A/dt

(D) –dC_A/dt

GATE 1996

Answer: (C)

For a tubular reactor with space time τ and residence time θ, the following statement holds

(A) τ and θ are always equal

(B) τ = θ when the fluid density changes in the reactor

(D) τ = θ for a non-isothermal reactor

GATE 1996

Answer: (C)

For an isothermal variable volume batch reactor, the following reaction is applicable for a first order irreversible reaction.

GATE 1996

Answer: (C)

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GATE Chemical Engineering Questions and Answers – Chemical Reaction Engineering

2021-02-25T14:37:00.008+05:30

The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 K to 500 K. Assuming Transition state theory is valid, the value of E/R is

(A) 8987 K

(B) 9210 K

(D) 8621 K

GATE 1995

Answer: (C)

The dimensions of rate constant for reaction 3A → B are lit/(g.mol.min). Therefore the reaction order is

(A) 0

(B) 1

(D) 3

GATE 1995

Answer: (C)

A first order reaction A → B occurs in an isothermal porous catalyst pellet of spherical shape. If the concentration of A at the centre of the pellet is much less than that at the external surface, the process is limited by

(A) Diffusion within the pellet

(B) Reaction

(D) None of the above

GATE 1995

Answer: (A)

To maximize the formation of R in the simultaneous reactions

We should have

(A) Low C_A, low C_B

(B) Low C_A, high C_B

(D) High C_A, high C_B

GATE 1994

Answer: (B)

For the gaseous reaction 2A → B where the feed consists of 50 mole% A and 50 mole% inerts, the expansion factor is

(A) 1

(B) -0.5

(D) 0

GATE 1994

Answer: (C)

The conversion of a reactant undergoing a first order reaction at a time equal to three times the half life of the reaction is

(A) 0.875

(B) 0.50

(D) Not impossible to calculate because of insufficient data

GATE 1992

Answer: (A)

A gaseous reaction A → 2B + C takes place isothermally in a constant pressure reactor. Starting with a gaseous mixture containing 50% A (rest inerts), the ratio of final to initial volume is found to be 1.6. the percentage conversion of A is

(A) 30

(B) 50

(D) 74

GATE 1992

Answer: (C)

The unit of frequency factor in Arrhenius equation

(A) Are the same as those of the rate constant

(B) Depend on the order of the reaction

(D) Are cycles per unit time

GATE 1992

Answer: (A)

Thiele modulus is defined as

(A) D/K

(B) K/D

(D) LK/D

GATE 1991

Answer: (C)

The reaction between A and B produces the desired product R as well as the unwanted product S. what level of reactant concentration (high, medium, low) should we use for the following reaction scheme in order to maximize the conversion of A to R.

Reaction scheme:

(A) Low C_A, low C_B

(B) High C_B, any C_A

(D) High C_A, any C_B

GATE 1991

Answer: (B)

The rate of a liquid phase reaction of the type A + B → P is found to be independent of concentration of A and B and equal to 1 kmol/m³.min at 300 K. Find the conversion in a mixed flow reactor having volume equal to 2 m³ with feed concentration of A and b equal to 5 kmol/m³, feed flow rate equal to 1 m³/min and the reactor temperature equal to 300 K.

(A) 0.4

(B) 0.5

(D) 0.7

GATE 1991

Answer: (A)

For an elementary reaction A + B → products, the reaction rate at 500 K is ten times that at 400 K. Calculate the activation energy for this reaction

(A) 38.29 KJ/g.mol

(B) 42.25 KJ/g.mol

(D) 48.35 KJ/g.mol

GATE 1990

Answer: (A)

What is the exit conversion of reactant A for a zero order reaction taking place in a CSTR with the following data (rate constant = 1 mol/min.lit, feed concentration = 1 mole/lit, feed flow rate = 0.5 lit/min and reactor volume = 1 lit)

(A) 50%

(B) 75%

(D) 200%

GATE 1990

Answer: (D)

An exothermic gas phase reaction proceeds according to the equation 3A + 2D 2R. The equilibrium conversion for this reaction

(A) Increases with increase in temperature

(B) Decreases on dilution with an inert gas

(D) Is unbaffled by the presence of a catalyst

GATE 1990

Answer: (D)

In a homogeneous gas phase reaction A + 2B → R + S. What is the relationship between r_A and r_B?

(A) 2r_A = r_B

(B) r_A = 2r_B

(D) none of these

GATE 1990

Answer: (A)

For the following reaction, the rate constant at 373 K is 0.5 per min 0.5 A + B → C. The overall order of reaction is

(A) 0.5

(B) 1.0

(D) 0

GATE 1989

Answer: (B)

From the stoichiometry, one can say that the following reaction is non-elementary

N₂ + 3H₂ → 2NH₃

The reason is

(A) No elementary reaction has an order greater than 2

(B) The order of the forward reaction is not the same as that of the backward reaction

(D) None of these

GATE 1989

Answer: (A)

In transition state theory the rate of the reaction is derived by assuming that the activated complex in equilibrium with

(A) The products

(B) The reactants

(D) None of the above

GATE 1988

Answer: (B)

Liquid A decomposes by first order kinetics in an isothermal batch reactor. 50% of A is converted in 300 seconds. The time required for a conversion of 75% is

(A) 300 × 0.75/0.25 sec

(B) 300 ln 1 sec

(D) 300 {(ln0.25)/(ln0.5)}

GATE 1988

Answer: (D)

The reaction A → B occurs in an isothermal catalyst pellet under steady state conditions. If the diffusion of A into the pellet is the rate controlling steps, the rate of diffusion of A is

(A) Faster than the rate of reaction

(B) Equal to the rate of reaction

(D) May be faster or slower depending on the kinetics

GATE 1988

Answer: (C)

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Related Article:

GATE Chemical Engineering Questions and Answers – Chemical Process Technology