Power Plants

Holtekamp steam power plant project submerged by sea water

noreply@blogger.com (Energetic) — Sat, 12 Mar 2011 07:58:00 +0000

The impact of the tsunami that came to Papua make the Holtekamp steam power plant project submerged by sea water, 115-150 cm.

President Director of PLN said "On Friday (11/03/2011) around 23:00 hours local time, the sea water entering the power plant on the north coast of Papua Holtekamp, between Jayapura and Papua New Guinea border. Area warehouses, and a location that is not a project area"said Dahlan.

Because of this puddle, the material is placed in storage projects part submerged. Containers are also a storehouse of material even abject 20-50 meters.

"When the inventory is being done by contractors and PLN. At the time of the incident there was no officer there. All personnel have been evacuated since at 18:30, and they were returning to the project site at 01.00 am.

Dahlan said the plant project is one of the acceleration program generating 10,000 MW. The new coal-powered power plant to be completed next year.

List of Electricity Production by Country

noreply@blogger.com (Energetic) — Tue, 08 Mar 2011 12:51:00 +0000

List of Electricity Production by Country

Rank	Country/Region	Electricity - production (kWh)	Date of information
-	World	19,894,777,395,212	2007
1	United States	4,110,259,050,000	2008
2	China	3,221,798,270,000	2008
3	Japan	1,009,445,000,000	2008
4	Russia	982,998,790,000	2008
5	India	787,546,450,000	2008
6	Canada	614,227,000,000	2008
7	Germany	589,042,000,000	2008
8	France	539,022,000,000	2008
9	Brazil	448,913,750,000	2008
10	Korea, South	415,970,000,000	2008
11	United Kingdom	363,203,000,000	2008
12	Italy	292,544,200,000	2008
13	Spain	288,549,000,000	2008
14	Australia	249,914,000,000	2008
15	Mexico	244,952,000,000	2008
16	South Africa	240,254,482,600	2007
17	Taiwan	224,985,000,000	2007
18	Ukraine	195,130,500,000	2007
19	Iran	193,308,000,000	2007
20	Turkey	190,973,000,000	2007
21	Saudi Arabia	190,127,000,000	2007
22	Poland	159,292,000,000	2007
23	Sweden	149,151,000,000	2007
24	Indonesia	147,045,000,000	2007
25	Thailand	147,025,000,000	2007
26	Norway	137,708,563,000	2007
27	Venezuela	124,906,000,000	2007
28	Argentina	120,828,000,000	2007
29	Egypt	118,966,000,000	2007
30	Malaysia	104,950,000,000	2007
31	Netherlands	103,429,000,000	2007
32	Pakistan	97,056,700,000	2007
33	Czech Republic	88,142,000,000	2007
34	Finland	81,182,000,000	2007
35	Belgium	80,840,000,000	2005
36	Kazakhstan	76,145,363,800	2007
37	United Arab Emirates	70,792,000,000	2007
38	Paraguay	70,000,000,000	2007
39	Switzerland	68,026,022,170	2007
40	Greece	67,800,000,000	2007
41	Austria	63,741,000,000	2007
42	Romania	60,556,000,000	2007¨
43	Chile	60,148,000,000	2007
44	Philippines	59,611,787,905	2007
45	Vietnam	59,010,000,000	2007
46	Portugal	53,635,000,000	2007
47	Colombia	53,624,072,370	2007
48	Israel	50,411,000,000	2007
49	Uzbekistan	49,376,000,000	2007
50	Bulgaria	43,670,000,000	2007
51	New Zealand	43,357,900,000	2007
52	Kuwait	41,500,000,000	2007
53	Hungary	40,000,000,000	2007
54	Denmark	39,227,000,000	2007
55	Hong Kong	38,947,777,780	2007
56	Singapore	37,485,360,000	2007
57	Algeria	36,684,000,000	2007
58	Syria	34,940,000,000	2007 est.
59	Serbia	34,834,000,000	2007
60	Iraq	33,530,000,000	2007 est.
61	Belarus	31,862,000,000	2007
62	Peru	29,551,000,000	2007
63	Slovakia	27,954,000,000	2007
64	Ireland	27,178,000,000	2007
65	Bangladesh	25,486,000,000	2007
66	Libya	23,983,000,000	2007
67	Puerto Rico	23,720,000,000	2007
68	Nigeria	21,920,000,000	2007
69	Morocco	21,556,000,000	2007
70	Korea, North	20,895,000,000	2007
71	Azerbaijan	20,580,000,000	2008
72	Qatar	18,525,000,000	2008
73	Ecuador	16,747,000,000	2007
74	Tajikistan	16,083,000,000	2008
75	Cuba	16,887,190,000	2007
76	Iceland	16,142,700,000	2008
77	Kyrgyzstan	15,961,000,000	2007
78	Mozambique	15,914,000,000	2007
79	Oman	15,085,000,000	2008
80	Slovenia	14,139,190,000	2007
81	Turkmenistan	14,128,000,000	2008
82	Dominican Republic	14,019,000,000	2007
83	Tunisia	13,785,000,000	2007
84	Jordan	12,213,000,000	2007
85	Lithuania	12,093,850,000	2007
86	Croatia	11,469,000,000	2007
87	Estonia	11,460,000,000	2007
88	Bosnia and Herzegovina	11,315,000,000	2007
89	Bahrain	10,254,000,000	2007
90	Zambia	9,752,000,000	2007
91	Sri Lanka	9,507,000,000	2007
92	Uruguay	9,265,000,000	2007
93	Lebanon	9,030,000,000	2007
94	Zimbabwe	8,890,000,000	2007
95	Costa Rica	8,808,000,000	2007
96	Guatemala	8,425,000,000	2007
97	Congo, Democratic Republic of the	8,217,000,000	2007
98	Georgia	7,970,000,000	2008
99	Jamaica	7,324,000,000	2007
100	Trinidad and Tobago	7,202,000,000	2007
101	Ghana	6,746,000,000	2007
102	Burma	6,286,000,000	2007
103	Macedonia	6,051,000,000	2007
104	Armenia	5,941,000,000	2006
105	Panama	5,661,000,000	2005
106	Kenya	5,502,000,000	2005
107	Albania	5,385,000,000	2005
108	Honduras	5,339,000,000	2005
109	El Salvador	5,316,000,000	2006
110	Côte d'Ivoire	5,305,000,000	2005
111	Bolivia	5,293,000,000	2006
112	Latvia	4,778,000,000	2005
113	Cyprus	4,618,000,000	2006
114	Yemen	4,456,000,000	2005 est.
115	Cameroon	4,090,000,000	2005
116	Kosovo	3,996,000,000	2006
117	Sudan	3,944,000,000	2005
118	Moldova	3,881,000,000	2005
119	Papua New Guinea	3,698,000,000	2005
120	Mongolia	3,430,000,000	2006
121	Luxembourg	3,156,000,000	2005 est.
122	Ethiopia	2,864,000,000	2005
123	Montenegro	2,864,000,000	2005 est.
124	Nicaragua	2,778,000,000	2006
125	Brunei	2,735,000,000	2005
126	Angola	2,585,000,000	2005
127	Nepal	2,511,000,000	2006
128	Mauritius	2,350,000,000	2006
129	Senegal	2,159,000,000	2006
130	Malta	2,106,000,000	2005
131	Bhutan	2,000,000,000	2005
132	Uganda	1,983,000,000	2005
133	Bahamas, The	1,894,000,000	2005
134	Tanzania	1,880,000,000	2005
135	Guam	1,793,000,000	2005
136	Laos	1,715,000,000	2005
137	Namibia	1,688,000,000	2005
138	Macau	1,670,000,000	2006
139	Suriname	1,530,000,000	2005
140	Gabon	1,520,000,000	2005
141	New Caledonia	1,508,000,000	2005
142	Malawi	1,397,000,000	2005
143	Netherlands Antilles	1,175,000,000	2005
144	Fiji	1,046,000,000	2005
145	Madagascar	1,046,000,000	2005
146	U.S. Virgin Islands	996,100,000	2005
147	Barbados	953,000,000	2005
148	Botswana	912,000,000	2005
149	Guinea	840,000,000	2006
150	Guyana	807,300,000	2005
151	Mali	804,000,000	2006
152	Aruba	770,000,000	2005
153	Afghanistan	754,200,000	2005
154	Bermuda	618,000,000	2005
155	Haiti	535,000,000	2005
156	Burkina Faso	516,200,000	2005
157	French Polynesia	462,000,000	2005
158	Swaziland	460,000,000	2007
159	Cayman Islands	400,000,000	2005
160	Congo, Republic of the	400,000,000	2007
161	Lesotho	350,000,000	2005
162	Liberia	319,300,000	2005
163	Djibouti	306,000,000	2006
164	Saint Lucia	304,200,000	2005
165	Greenland	300,000,000	2005
166	Faroe Islands	290,000,000	2005
167	Eritrea	274,000,000	2005
168	Somalia	270,000,000	2005
169	Seychelles	252,000,000	2006
170	Mauritania	248,000,000	2005
171	Sierra Leone	245,000,000	2005
172	Niger	234,100,000	2005
173	Belize	200,000,000	2007 est.
174	Micronesia, Federated States of	192,000,000	2002
175	American Samoa	180,000,000	2005
176	Togo	176,000,000	2005
177	Maldives	169,000,000	2005
178	Grenada	150,000,000	2005
179	Gambia, The	145,000,000	2005
180	Gibraltar	141,000,000	2005
181	Burundi	137,000,000	2005
182	Cambodia	134,000,000	2005
183	Saint Kitts and Nevis	125,000,000	2005
184	Saint Vincent and the Grenadines	115,000,000	2005
185	Central African Republic	109,000,000	2005
186	Antigua and Barbuda	105,000,000	2005
187	Samoa	105,000,000	2005
188	Benin	105,000,000	2005
189	Chad	95,000,000	2005
190	Rwanda	95,000,000	2005
191	Western Sahara	85,000,000	2005
192	Dominica	80,000,000	2005
193	Solomon Islands	60,000,000	2005
194	Guinea-Bissau	60,000,000	2005
195	Tonga	54,000,000	2006
196	Saint Pierre and Miquelon	50,000,000	2005
197	Cape Verde	45,000,000	2005
198	British Virgin Islands	45,000,000	2005
199	Vanuatu	41,000,000	2005
200	Cook Islands	30,000,000	2005
201	Nauru	30,000,000	2005
202	Equatorial Guinea	28,000,000	2005
203	Comoros	20,000,000	2005
204	Montserrat	20,000,000	2005
205	Sao Tome and Principe	18,000,000	2005
206	Falkland Islands	16,000,000	2005
207	Turks and Caicos Islands	11,570,000	2005
208	Kiribati	9,000,000	2005
209	Saint Helena	8,000,000	2005
210	Niue	3,000,000	2005
211	Gaza Strip	140,000	2005

List of Electricity Price by Country in Europe

noreply@blogger.com (Energetic) — Wed, 03 Nov 2010 14:40:00 +0000

List of Electricity Price by Country in Europe:

DOMESTIC ELECTRICITY PRICES –
€ per kWh electricity Consumption: 3500 kWh/year (30% during nighttime) Average amount in euro per one kilowatt-hour of electricity for domestic consumers. Incl. energy taxes & VAT. Effective: November '09		€ per kWh electricity Consumption: 7500 kWh/year (30% during nighttime) Average amount in euro per one kilowatt-hour of electricity for domestic consumers. Incl. energy taxes & VAT. Effective: November '09
Austria	€ 0.171	Austria	€ 0.147
Belgium	€ 0.172	Belgium	€ 0.152
Bulgaria	€ 0.093	Bulgaria	€ 0.077
Cyprus	€ 0.144	Cyprus	€ 0.142
Czech Rep,	€ 0.116	Czech Rep,	€ 0.087
Denmark	€ 0.268	Denmark	€ 0.232
Estonia	€ 0.091	Estonia	€ 0.076
Finland	€ 0.128	Finland	€ 0.107
France	€ 0.138	France	€ 0.117
Germany	€ 0.211	Germany	€ 0.204
Greece	€ 0.089	Greece	€ 0.089
Hungary	€ 0.148	Hungary	€ 0.146
Ireland	€ 0.184	Ireland	€ 0.153
Italy	€ 0.260	Italy	€ 0.224
Latvia	€ 0.088	Latvia	€ 0.077
Lithuania	€ 0.091	Lithuania	€ 0.079
Luxembourg	€ 0.189	Luxembourg	€ 0.182
Malta	€ 0.105	Malta	€ 0.120
Netherlands	€ 0.241	Netherlands	€ 0.240
Poland	€ 0.140	Poland	€ 0.127
Portugal	€ 0.172	Portugal	€ 0.143
Romania	€ 0.130	Romania	€ 0.114
Slovakia	€ 0.179	Slovakia	€ 0.136
Slovenia	€ 0.132	Slovenia	€ 0.113
Spain	€ 0.143	Spain	€ 0.117
Sweden	€ 0.195	Sweden	€ 0.192
United Kingdom	€ 0.138	United Kingdom	€ 0.128

List of World Electricity Consumption

noreply@blogger.com (Energetic) — Thu, 23 Sep 2010 19:04:00 +0000

This list of world electricity consumption based on The World Factbook. In addition, the per capita data for many countries may be slightly inaccurate as population data may not be for the same year that the consumption data are.

Average power per capita was calculated according to the formula:

Power = Consumption·1,000,000/(365.25·24)/population, where power is in watts and consumption is in MW·h/yr.

Rank	Country	Electricity consumption (MW·h/yr)	Population	Average power per capita (watts per person)
—	World	17,109,665,000	6,464,750,000	297
1	United States	3,872,598,000	298,213,000	1,460
2	China	3,650,600,000	1,315,844,000	277
—	European Union^[5]	2,950,297,000	459,387,000	700
3	Japan	1,007,067,000	128,085,000	868
4	Russia	840,380,000	141,927,297	785
5	India	568,000,000	1,103,371,000	50.5
6	Germany	547,326,000	82,329,758	822.22
7	Canada	536,054,000	32,268,000	1,910
8	France	447,233,000	60,496,000	851
9	Brazil	403,029,000	186,405,000	226
10	South Korea	386,169,000	47,817,000	879
11	United Kingdom	345,798,000	59,668,000	667
12	Italy	307,100,000	58,093,000	603
13	Spain	243,000,000	43,064,000	644
14	South Africa	241,400,000	47,432,000	581
15	Taiwan (Republic of China)	221,000,000	22,894,384	1,101
16	Australia	219,800,000	20,155,000	1,244
17	Mexico	183,300,000	107,029,000	195
18	Ukraine	181,900,000	46,481,000	446
19	Saudi Arabia	146,900,000	24,573,000	682
20	Iran	136,200,000	69,515,000	224
21	Sweden	134,100,000	9,041,000	1,692
22	Turkey	129,000,000	73,193,000	201
23	Poland	120,400,000	38,530,000	356
24	Thailand	117,700,000	64,233,000	209
25	Norway	113,900,000	4,620,000	2,812
26	Netherlands	108,200,000	16,299,000	757
27	Indonesia	108,000,000	222,781,000	55.3
28	Argentina	88,980,000	38,747,000	262
29	Finland	88,270,000	5,249,000	1,918
30	Egypt	84,490,000	74,033,000	130
31	Belgium	82,990,000	10,419,000	909
32	Malaysia	78,720,000	25,347,000	354
33	Kazakhstan	76,430,000	14,825,000	588
34	Venezuela	73,360,000	26,749,000	313
35	Pakistan	67,060,000	157,935,000	48.4
36	Austria	60,250,000	8,189,000	839
37	Czech Republic	59,720,000	10,220,000	667
38	Romania	58,490,000	21,711,000	307
39	Switzerland	58,260,000	7,252,000	916
40	Greece	54,310,000	11,120,000	557
41	United Arab Emirates	52,620,000	4,496,000	1,335
42	Vietnam	51,350,000	84,238,000	69.5
43	Portugal	48,550,000	10,495,000	528
44	Chile	48,310,000	16,295,000	338
45	Uzbekistan	47,000,000	26,593,000	202
46	Philippines	46,860,000	83,054,000	64.4
47	Israel	43,280,000	6,725,000	734
—	Hong Kong	40,300,000	7,041,000	653
48	Colombia	38,910,000	45,600,000	97.3
49	Bulgaria	37,400,000	7,726,000	552
50	New Zealand	37,390,000	4,028,000	1,059
51	Kuwait	36,280,000	2,687,000	1,540
52	Hungary	35,980,000	10,098,000	406
53	Singapore	35,920,000	4,326,000	947
54	Iraq	35,840,000	28,807,000	142
55	Denmark	34,020,000	5,431,000	715
56	Syria	34,000,000	19,043,000	204
57	Serbia	33,050,000	9,778,991	386
58	Belarus	29,490,000	9,755,000	345
59	Algeria	27,520,000	32,854,000	95.6
60	Azerbaijan	27,500,000	8,411,000	373
61	Slovakia	24,930,000	5,401,000	527
62	Ireland	24,090,000	4,148,000	663
—	Puerto Rico (US)	23,210,000	4,000,000	669
63	Peru	22,590,000	27,968,000	92.1
64	Morocco	20,670,000	31,478,000	74.9
65	Bangladesh	19,490,000	141,822,000	15.7
66	North Korea	18,570,000	22,488,000	94.2
67	Libya	18,180,000	5,853,000	354
68	Tajikistan	17,900,000	6,507,000	314
69	Nigeria	16,880,000	131,530,000	14.6
70	Croatia	14,970,000	4,551,000	375
71	Cuba	13,870,000	11,269,000	140
72	Slovenia	13,710,000	1,967,000	795
73	Qatar	12,520,000	813,000	1,757
74	Zimbabwe	12,270,000	13,010,000	108
75	Tunisia	11,170,000	10,102,000	126
76	Lebanon	10,580,000	3,577,000	337
77	Lithuania	9,296,000	3,431,000	309
78	Mozambique	9,127,000	19,792,000	52.6
79	Ecuador	8,855,000	13,228,000	76.4
80	Dominican Republic	8,791,000	8,895,000	113
81	Oman	8,661,000	2,567,000	385
82	Zambia	8,655,000	11,668,000	84.6
83	Republic of Macedonia	8,651,000	2,034,000	485
84	Bosnia and Herzegovina	8,574,000	3,907,000	250
85	Jordan	8,490,000	5,703,000	170
86	Kyrgyzstan	8,206,000	5,264,000	178
87	Iceland	8,152,000	295,000	3,152
88	Georgia	8,146,000	4,474,000	208
89	Costa Rica	7,776,000	4,327,000	205
90	Bahrain	7,614,000	727,000	1,195
91	Turkmenistan	7,602,000	4,833,000	179
92	Trinidad and Tobago	7,083,000	1,305,000	619
93	Sri Lanka	7,072,000	20,743,000	38.9
94	Uruguay	7,030,000	3,463,000	232
95	Ghana	6,906,000	22,113,000	35.6
96	Estonia	6,888,000	1,330,000	591
97	Guatemala	6,361,000	12,599,000	57.6
98	Luxembourg	6,315,000	465,000	1,549
99	Jamaica	6,131,000	2,651,000	264
100	Latvia	6,090,000	2,307,000	301
101	Paraguay	6,000,000	6,158,000	111
102	Moldova	5,551,000	4,206,000	151
103	Armenia	5,454,000	3,016,000	206
104	El Salvador	5,319,000	6,881,000	88.2
105	Democratic Republic of the Congo	5,272,000	57,549,000	10.5
106	Panama	4,735,000	3,232,000	167
107	Kenya	4,464,000	34,256,000	14.9
108	Kosovo	4,281,000	2,100,000	233
109	Cyprus	4,135,000	835,000	565
110	Honduras	4,036,000	7,205,000	63.9
111	Burma	3,744,000	50,519,000	8.45
112	Papua New Guinea	3,439,000	5,887,000	66.6
113	Cameroon	3,435,000	16,322,000	24.0
114	Bolivia	3,385,000	9,182,000	42.1
115	Yemen	3,381,000	20,975,000	18.4
116	Albania	3,323,000	3,130,000	121
117	Sudan	3,298,000	36,233,000	10.4
118	Mongolia	2,940,000	2,646,000	127
119	Nicaragua	2,929,000	5,487,000	60.9
120	Côte d'Ivoire	2,900,000	18,154,000	18.2
121	Namibia	2,863,000	2,031,000	161
122	Brunei	2,625,000	374,000	801
123	Botswana	2,602,000	1,765,000	168
124	Ethiopia	2,577,000	77,431,000	3.80
—	Macau (PRC)	2,370,000	460,000	588
125	Angola	2,201,000	15,941,000	15.8
126	Mauritius	2,068,000	1,245,000	189
127	Nepal	1,960,000	27,133,000	8.24
128	Malta	1,959,000	402,000	556
129	Senegal	1,859,000	11,658,000	18.2
130	Bahamas	1,762,000	323,000	622
131	Uganda	1,674,000	28,816,000	6.63
—	Guam (US)	1,667,000	170,000	1,119
132	Suriname	1,423,000	449,000	362
—	New Caledonia (France)	1,403,000	237,000	675
133	Malawi	1,299,000	12,884,000	11.5
134	Gabon	1,241,000	1,384,000	102
135	Swaziland	1,200,000	1,032,000	133
136	Tanzania	1,199,000	38,329,000	3.57
137	Laos	1,193,000	5,924,000	23.0
138	Madagascar	973,200	18,606,000	5.97
—	United States Virgin Islands (US)	926,400	112,000	944
—	Netherlands Antilles (Netherlands)	891,000	183,000	555
139	Barbados	886,300	270,000	374
140	Guinea	832,900	9,402,000	10.11
141	Mali	804,000	13,518,000	6.78
142	Afghanistan	801,400	29,863,000	3.06
143	Guyana	750,700	751,000	114
144	Fiji	735,600	848,000	99.0
—	Aruba (Netherlands)	716,100	99,000	825
—	Jersey (UK)	630,100	149,000	482
145	Benin	587,000	8,439,000	7.93
146	Togo	576,000	6,145,000	10.7
—	Bermuda (UK)	574,800	64,000	1,025
147	Republic of the Congo	572,000	3,999,000	16.3
148	Burkina Faso	480,100	13,228,000	4.14
149	Niger	437,700	13,957,000	3.58
—	French Polynesia (France)	429,700	257,000	191
150	Bhutan	380,000	2,163,000	20.0
—	Cayman Islands (UK)	372,000	45,000	943
151	Lesotho	338,500	1,795,000	21.5
152	Haiti	322,000	8,528,000	4.31
153	Liechtenstein	318,340	35,000	1,038
154	Liberia	296,900	3,283,000	10.3
155	Saint Lucia	282,900	161,000	200
—	Greenland (Denmark)	279,000	57,000	558
—	Faroe Islands (Denmark)	269,700	47,000	655
156	Somalia	251,100	8,228,000	3.48
157	Mauritania	230,600	3,069,000	8.57
158	Eritrea	228,000	4,401,000	5.91
159	Sierra Leone	227,900	5,525,000	4.71
160	Djibouti	226,900	793,000	32.6
161	Seychelles	216,600	81,000	305
162	Cambodia	206,600	14,071,000	1.67
163	Rwanda	198,400	9,038,000	2.50
164	Federated States of Micronesia	178,600	110,000	185
—	American Samoa (US)	167,400	65,000	294
165	Belize	162,800	270,000	68.8
166	Burundi	161,400	7,548,000	2.44
167	Maldives	157,100	329,000	54.5
—	Gibraltar (UK)	141,000	28,000	574
168	Grenada	139,500	103,000	155
—	Mayotte (France)	139,200	186,452	85.2
169	The Gambia	134,900	1,517,000	10.14
170	Saint Kitts and Nevis	116,300	43,000	309
171	Saint Vincent and the Grenadines	107,000	119,000	103
172	Central African Republic	101,400	4,038,000	2.86
174	Antigua and Barbuda	97,650	81,000	138
173	Samoa	97,650	185,000	60.2
175	Chad	88,350	9,749,000	1.03
176	Western Sahara	79,050	341,000	26.4
177	Dominica	74,400	79,000	107
178	Guinea-Bissau	55,800	1,586,000	4.01
179	Solomon Islands	55,800	478,000	13.3
180	Tonga	47,000	102,000	52.6
—	Saint Pierre and Miquelon (France)	46,500	6,000	884
—	British Virgin Islands (UK)	41,850	22,000	217
181	Cape Verde	41,850	507,000	9.42
182	Vanuatu	38,130	211,000	20.6
—	Cook Islands (NZ)	27,900	18,000	177
183	Nauru	27,900	14,000	227
184	Equatorial Guinea	26,040	504,000	5.89
185	Comoros	18,600	798,000	2.66
186	Montenegro	18,600	620,145	3.42
—	Montserrat (UK)	18,600	4,000	530
187	São Tomé and Príncipe	16,740	157,000	12.2
—	Falkland Islands (Islas Malvinas) (UK)	14,880	3,000	566
—	Turks and Caicos Islands (UK)	10,760	26,000	47.2
188	Kiribati	8,370	99,000	9.64
—	Saint Helena (UK)	7,440	5,000	170
189	Tuvalu	3,000	10,000	34.2
—	Niue (NZ)	2,790	1,000	318
190	Gaza Strip	230	1,482,405	0.02
—	Andorra		67,000
—	Anguilla (UK)		12,000
—	East Timor		947,000
—	French Guiana (France)		187,000
—	Guadeloupe (France)		448,000
—	Isle of Man (UK)		77,000
—	Marshall Islands		62,000
—	Martinique (France)		396,000
—	Monaco		35,000
—	Northern Mariana Islands (US)		81,000
—	Palau		20,000
—	Palestinian territories		2,500,000
—	Pitcairn Islands (UK)		67
—	Réunion (France)		785,000
—	San Marino		28,000
—	Tokelau (NZ)		1,000
—	Vatican City		783
—	Wallis and Futuna (France)		15,000

Flue Gas Stack

noreply@blogger.com (Energetic) — Fri, 20 Aug 2010 08:06:00 +0000

A flue gas stack is a type of chimney, a vertical pipe, channel or similar structure through which combustion product gases called flue gases are exhausted to the outside air. Flue gases are produced when coal, oil, natural gas, wood or any other fuel is combusted in an industrial furnace, a power plant's steam-generating boiler, or other large combustion device. Flue gas is usually composed of carbon dioxide (CO₂) and water vapor as well as nitrogen and excess oxygen remaining from the intake combustion air. It also contains a small percentage of pollutants such as particulate matter, carbon monoxide, nitrogen oxides and sulfur oxides. The flue gas stacks are often quite tall, up to 400 meters (1300 feet) or more, so as to disperse the exhaust pollutants over a greater area and thereby reduce the concentration of the pollutants to the levels required by governmental environmental policy and environmental regulation.

When the flue gases are exhausted from stoves, ovens, fireplaces, or other small sources within residential abodes, restaurants, hotels, or other public buildings and small commercial enterprises, their flue gas stacks are referred to as chimneys.

Flue gas stack draft (or draught)

The combustion flue gases inside the flue gas stacks are much hotter than the ambient outside air and therefore less dense than the ambient air. That causes the bottom of the vertical column of hot flue gas to have a lower pressure than the pressure at the bottom of a corresponding column of outside air. That higher pressure outside the chimney is the driving force that moves the required combustion air into the combustion zone and also moves the flue gas up and out of the chimney. That movement or flow of combustion air and flue gas is called "natural draft (or draught)", "natural ventilation", "chimney effect", or "stack effect". The taller the stack, the more draft (or draught) is created.

The equation below provides an approximation of the pressure difference, ΔP, (between the bottom and the top of the flue gas stack) that is created by the draft:

where:
ΔP	= available pressure difference, in Pa
C	= 0.0342
a	= atmospheric pressure, in Pa
h	= height of the flue gas stack, in m
T_o	= absolute outside air temperature, in K
T_i	= absolute average temperature of the flue gas inside the stack, in K

The above equation is an approximation because it assumes that the molar mass of the flue gas and the outside air are equal and that the pressure drop through the flue gas stack is quite small. Both assumptions are fairly good but not exactly accurate.

The flue gas flow rate induced by the draft

As a "first guess" approximation, the following equation can be used to estimate the flue gas flow rate induced by the draft of a flue gas stack. The equation assumes that the molar mass of the flue gas and the outside air are equal and that the frictional resistance and heat losses are negligible:

where:
Q	= flue gas flow rate, m³/s
A	= cross-sectional area of chimney, m² (assuming it has a constant cross-section)
C	= discharge coefficient (usually taken to be from 0.65 to 0.70)
g	= gravitational acceleration at sea level, 9.807 m/s²
H	= height of chimney, m
T_i	= absolute average temperature of the flue gas in the stack, K
T_o	= absolute outside air temperature, K

Designing chimneys and stacks to provide the correct amount of natural draft involves a great many factors such as:

The height and diameter of the stack.
The desired amount of excess combustion air needed to assure complete combustion.
The temperature of the flue gases leaving the combustion zone.
The composition of the combustion flue gas, which determines the flue gas density.
The frictional resistance to the flow of the flue gases through the chimney or stack, which will vary with the materials used to construct the chimney or stack.
The heat loss from the flue gases as they flow through the chimney or stack.
The local atmospheric pressure of the ambient air, which is determined by the local elevation above sea level.

The calculation of many of the above design factors requires trial-and-error reiterative methods.

Governmental agencies in most countries have specific codes which govern how such design calculations must be performed. Many non-governmental organizations also have codes governing the design of chimneys and stacks (notably, the ASME codes).

Stack design

The design of large stacks poses considerable engineering challenges. Vortex shedding in high winds can cause dangerous oscillations in the stack, and may lead to its collapse. The use of helical faring is common to prevent this process occurring at or close to the resonant frequency of the stack.

Other items of interest

Some fuel-burning industrial equipment does not rely upon natural draft. Many such equipment items use large fans or blowers to accomplish the same objectives, namely: the flow of combustion air into the combustion chamber and the flow of the hot flue gas out of the chimney or stack.

A great many power plants are equipped with facilities for the removal of sulfur dioxide (i.e., flue gas desulfurization), nitrogen oxides (i.e, selective catalytic reduction, exhaust gas recirculation, thermal deNOx, or low NOx burners) and particulate matter (i.e., electrostatic precipitator)s. At such power plants, it is possible to use a cooling tower as a flue gas stack. Examples can be seen in Germany at the Power Station Staudinger Grosskrotzenburg and at the Rostock Power Station. Power plants without flue gas purification, would experience serious corrosion in such stacks.

In the United States and a number of other countries, atmospheric dispersion modeling studies are required to determine the flue gas stack height needed to comply with the local air pollution regulations. The United States also limits the maximum height of a flue gas stack to what is known as the "Good Engineering Practice (GEP)" stack height. In the case of existing flue gas stacks that exceed the GEP stack height, any air pollution dispersion modeling studies for such stacks must use the GEP stack height rather than the actual stack height.

Flue-gas desulfurization

noreply@blogger.com (Energetic) — Wed, 18 Aug 2010 22:20:00 +0000

Flue gas desulfurization (FGD) is a technology used to remove sulfur dioxide (SO₂) from the exhaust flue gases of fossil fuel power plants. Fossil fuel power plants burn coal or oil to produce steam for steam turbines, which in turn drive electricity generators.

Sulfur dioxide is one of the elements forming acid rain. Tall flue gas stacks disperse emissions by diluting the pollutants in ambient air and transporting them to other regions.

As stringent environmental regulations regarding SO₂ emissions have been enacted in many countries, SO₂ is now being removed from flue gases by a variety of methods. The below is among the common methods used:

Wet scrubbing using a slurry of alkaline sorbent, usually limestone or lime, or seawater to scrub gases;
Spray-dry scrubbing using similar sorbent slurries;
Wet sulfuric acid process recovering sulfur in the form of commercial quality sulfuric acid;
SNOX Flue gas desulfurization removes sulfur dioxide, nitrogen oxides and particulates from flue gases;
Dry sorbent injection systems.

For a typical coal-fired power station, FGD will remove 95 percent or more of the SO₂ in the flue gases.

History

Methods of removing sulfur dioxide from boiler and furnace exhaust gases have been studied for over 150 years. Early ideas for flue gas desulfurization were established in England around 1850.

With the construction of large scale power plants in England in the 1920s, the problems associated with large volumes of SO₂ from a single site began to concern the public. The SO₂ emissions problem did not receive much attention until 1929, when the House of Lords upheld the claim of a landowner against the Barton Electricity Works of the Manchester Corporation for damages to his land resulting from SO₂ emissions. Shortly thereafter, a press campaign was launched against the erection of power plants within the confines of London. This outcry led to the imposition of SO₂ controls on all such power plants.

The first major FGD unit at a utility was installed in 1931 at Battersea Station, owned by London Power Company. In 1935, an FGD system similar to that installed at Battersea went into service at Swansea Power Station. The third major FGD system was installed in 1938 at Fulham Power Station. These three early large-scale FGD installations were abandoned during World War II. Large-scale FGD units did not reappear at utilities until the 1970s, where most of the installations occurred in the United States and Japan.

As of June 1973, there were 42 FGD units in operation, 36 in Japan and 6 in the United States, ranging in capacity from 5 MW to 250 MW. As of around 1999 and 2000, FGD units were being used in 27 countries, and there were 678 FGD units operating at a total power plant capacity of about 229 gigawatts. About 45% of the FGD capacity was in the U.S., 24% in Germany, 11% in Japan, and 20% in various other countries. Approximately 79% of the units, representing about 199 gigawatts of capacity, were using lime or limestone wet scrubbing. About 18% (or 25 gigawatts) utilized spray-dry scrubbers or sorbent injection systems.

Sulfuric acid mist formation

Fossil fuels such as coal and oil contain a significant amount of sulfur. When fossil fuels are burned, about 95 percent or more of the sulfur is generally converted to sulfur dioxide (SO₂). Such conversion happens under normal conditions of temperature and of oxygen present in the flue gas. However, there are circumstances under which such reaction may not occur.

For example, when the flue gas has too much oxygen and the SO₂ is further oxidized to sulfur trioxide (SO₃). Actually, too much oxygen is only one of the ways that SO₃ is formed. Gas temperature is also an important factor. At about 800 °C, formation of SO₃ is favored. Another way that SO₃ can be formed is through catalysis by metals in the fuel. Such reaction is particularly true for heavy fuel oil, where a significant amount of vanadium is present. In whatever way SO₃ is formed, it does not behave like SO₂ in that it forms a liquid aerosol known as sulfuric acid (H₂SO₄) mist that is very difficult to remove. Generally, about 1% of the sulfur dioxide will be converted to SO₃. Sulfuric acid mist is often the cause of the blue haze that often appears as the flue gas plume dissipates. Increasingly, this problem is being addressed by the use of wet electrostatic precipitators.

FGD chemistry

Basic principles

Most FGD systems employ two stages: one for fly ash removal and the other for SO₂ removal. Attempts have been made to remove both the fly ash and SO₂ in one scrubbing vessel. However, these systems experienced severe maintenance problems and low removal efficiency. In wet scrubbing systems, the flue gas normally passes first through a fly ash removal device, either an electrostatic precipitator or a wet scrubber, and then into the SO₂ absorber. However, in dry injection or spray drying operations, the SO₂ is first reacted with the sorbent and then the flue gas passes through a particulate control device.

Another important design consideration associated with wet FGD systems is that the flue gas exiting the absorber is saturated with water and still contains some SO₂. These gases are highly corrosive to any downstream equipment such as fans, ducts, and stacks. Two methods that can minimize corrosion are: (1) reheating the gases to above their dew point, or (2) choosing construction materials and design conditions that allow equipment to withstand the corrosive conditions. Both alternatives are expensive, and engineers designing the system determine which method to use on a site-by-site basis.

Scrubbing with a basic solid or solution

SO₂ is an acid gas and thus the typical sorbent slurries or other materials used to remove the SO₂ from the flue gases are alkaline. The reaction taking place in wet scrubbing using a CaCO₃ (limestone) slurry produces CaSO₃ (calcium sulfite) and can be expressed as:

CaCO₃ (solid) + SO₂ (gas) → CaSO₃ (solid) + CO₂ (gas)

When wet scrubbing with a Ca(OH)₂ (lime) slurry, the reaction also produces CaSO₃ (calcium sulfite) and can be expressed as:

Ca(OH)₂ (solid) + SO₂ (gas) → CaSO₃ (solid) + H₂O (liquid)

When wet scrubbing with a Mg(OH)₂ (magnesium hydroxide) slurry, the reaction produces MgSO₃ (magnesium sulfite) and can be expressed as:

Mg(OH)₂ (solid) + SO₂ (gas) → MgSO₃ (solid) + H₂O (liquid)

To partially offset the cost of the FGD installation, in some designs, the CaSO₃ (calcium sulfite) is further oxidized to produce marketable CaSO₄ · 2H₂O (gypsum). This technique is also known as forced oxidation:

CaSO₃ (solid) + H₂O (liquid) + ½O₂ (gas) → CaSO₄ (solid) + H₂O

A natural alkaline usable to absorb SO₂ is seawater. The SO₂ is absorbed in the water, and when oxygen is added reacts to form sulfate ions SO₄- and free H⁺. The surplus of H⁺ is offset by the carbonates in seawater pushing the carbonate equilibrium to release CO₂ gas:

SO₂ (gas) + H₂O + ½O₂ (gas)→ SO₄^2- (solid) + 2H⁺

HCO₃^- + H⁺ → H₂O + CO₂ (gas)

Types of wet scrubbers used in FGD

To promote maximum gas-liquid surface area and residence time, a number of wet scrubber designs have been used, including spray towers, venturis, plate towers, and mobile packed beds. Because of scale buildup, plugging, or erosion, which affect FGD dependability and absorber efficiency, the trend is to use simple scrubbers such as spray towers instead of more complicated ones. The configuration of the tower may be vertical or horizontal, and flue gas can flow cocurrently, countercurrently, or crosscurrently with respect to the liquid. The chief drawback of spray towers is that they require a higher liquid-to-gas ratio requirement for equivalent SO2 removal than other absorber designs.

Mobile-bed scrubbers

Venturi-rod scrubbers

A venturi scrubber is a converging/diverging section of duct. The converging section accelerates the gas stream to high velocity. When the liquid stream is injected at the throat, which is the point of maximum velocity, the turbulence caused by the high gas velocity atomizes the liquid into small droplets, which creates the surface area necessary for mass transfer to take place. The higher the pressure drop in the venturi, the smaller the droplets and the higher the surface area. The penalty is in power consumption.

For simultaneous removal of SO₂ and fly ash, venturi scrubbers can be used. In fact, many of the industrial sodium-based throwaway systems are venturi scrubbers originally designed to remove particulate matter. These units were slightly modified to inject a sodium-based scrubbing liquor. Although removal of both particles and SO₂ in one vessel can be economic, the problems of high pressure drops and finding a scrubbing medium to remove heavy loadings of fly ash must be considered. However, in cases where the particle concentration is low, such as from oil-fired units, it can be more effective to remove particulate and SO₂ simultaneously.

Plate towers

Packed bed scrubbers

A packed scrubber consists of a tower with packing material inside. This packing material can be in the shape of saddles, rings, or some highly specialized shapes designed to maximize contact area between the dirty gas and liquid. Packed towers typically operate at much lower pressure drops than venturi scrubbers and are therefore cheaper to operate. They also typically offer higher SO₂ removal efficiency. The drawback is that they have a greater tendency to plug up if particles are present in excess in the exhaust air stream.

Spray towers

A spray tower is the simplest type of scrubber. It consists of a tower with spray nozzles, which generate the droplets for surface contact. Spray towers are typically used when circulating a slurry (see below). The high speed of a venturi would cause erosion problems, while a packed tower would plug up if it tried to circulate a slurry.

Counter-current packed towers are infrequently used because they have a tendency to become plugged by collected particles or to scale when lime or limestone scrubbing slurries are used.

Scrubbing reagent

As explained above, alkaline sorbents are used for scrubbing flue gases to remove SO₂. Depending on the application, the two most important are lime and sodium hydroxide (also known as caustic soda). Lime is typically used on large coal or oil fired boilers as found in power plants, as it is very much less expensive than caustic soda. The problem is that it results in a slurry being circulated through the scrubber instead of a solution. This makes it harder on the equipment. A spray tower is typically used for this application. The use of lime results in a slurry of calcium sulfite (CaSO₃) that must be disposed of. Fortunately, calcium sulfite can be oxidized to produce by-product gypsum (CaSO₄ · 2H₂O) which is marketable for use in the building products industry.

Caustic soda is limited to smaller combustion units because it is more expensive than lime, but it has the advantage that it forms a solution rather than a slurry. This makes it easier to operate. It produces a solution of sodium sulfite/bisulfite (depending on the pH), or sodium sulfate that must be disposed of. This is not a problem in a kraft pulp mill for example, where this can be a source of makeup chemicals to the recovery cycle.

Scrubbing with sodium sulfite solution

It is possible to scrub sulfur dioxide by using a cold solution of sodium sulfite, this forms a sodium hydrogen sulfite solution. By heating this solution it is possible to reverse the reaction to form sulfur dioxide and the sodium sulfite solution.

In some ways this can be thought of as being similar to the reversible liquid-liquid extraction of an inert gas such as xenon or radon (or some other solute which does not undergo a chemical change during the extraction) from water to another phase. While a chemical change does occur during the extraction of the sulfur dioxide from the gas mixture, it is the case that the extraction equilibrium is shifted by changing the temperature rather than by the use of a chemical reagent.

Gas phase oxidation followed by reaction with ammonia

A new, emerging flue gas desulfurization technology has been described by the IAEA. It is a radiation technology where an intense beam of electrons is fired into the flue gas at the same time as ammonia is added to the gas. The Chendu power plant in China started up such a flue gas desulfurization unit on a 100 MW scale in 1998. The Pomorzany power plant in Poland also started up a similar sized unit in 2003 and that plant removes both sulfur and nitrogen oxides. Both plants are reported to be operating successfully. However, the accelerator design principles and manufacturing quality need further improvement for continuous operation in industrial conditions.

No radioactivity is required or created in the process. The electron beam is generated by a device similar to the electron gun in a TV set. This device is called an accelerator. This is an example of a radiation chemistry process where the physical effects of radiation are used to process a substance.

The action of the electron beam is to promote the oxidation of sulfur dioxide to sulfur(VI) compounds. The ammonia reacts with the sulfur compounds thus formed to produce ammonium sulfate which can be used as a fertilizer according to the IAEA. In addition, it can be used to lower the nitrogen oxide content of the flue gas. This method has attained industrial plant scale.

Facts and statistics

Flue gas desulfurization scrubbers have been applied to combustion units firing coal and oil that range in size from 5 MW to 1500 MW. Scottish Power are spending £400 million installing FGD at Longannet power station which has a capacity of over 2 GW. Dry scrubbers and spray scrubbers have generally been applied to units smaller than 300 MW.

Approximately 85% of the flue gas desulfurization units installed in the US are wet scrubbers, 12% are spray dry systems and 3% are dry injection systems.

The highest SO₂ removal efficiencies (greater than 90%) are achieved by wet scrubbers and the lowest (less than 80%) by dry scrubbers. However, the newer designs for dry scrubbers are capable of achieving efficiencies in the order of 90%.

In spray drying and dry injection systems, the flue gas must first be cooled to about 10-20 °C above adiabatic saturation to avoid wet solids deposition on downstream equipment and plugging of baghouses.

The capital, operating and maintenance costs per short ton of SO₂ removed (in 2001 US dollars) are:

For wet scrubbers larger than 400 MW, the cost is $200 to $500 per ton
For wet scrubbers smaller than 400 MW, the cost is $500 to $5,000 per ton
For spray dry scrubbers larger than 200 MW, the cost is $150 to $300 per ton
For spray dry scrubbers smaller than 200 MW, the cost is $500 to $4,000 per ton

Alternative methods of reducing sulfur dioxide emissions

An alternative to removing sulfur from the flue gases after burning is to remove the sulfur from the fuel before or during combustion. Hydrodesulfurization of fuel has been used for treating fuel oils before use. Fluidized bed combustion adds lime to the fuel during combustion. The lime reacts with the SO₂ to form sulfates which become part of the ash.

Electricity Generation

noreply@blogger.com (Energetic) — Thu, 12 Aug 2010 21:56:00 +0000

Electricity generation is the process of creating electricity from other forms of energy.

The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday. His basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet.

For electric utilities, it is the first process in the delivery of electricity to consumers. The other processes, electric power transmission, electricity distribution, and electrical power storage and recovery using pumped storage methods are normally carried out by the electrical power industry.

Electricity is most often generated at a power station by electromechanical generators, primarily driven by heat engines fueled by chemical combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. There are many other technologies that can be and are used to generate electricity such as solar photovoltaics and geothermal power.

Methods of generating electricity

There are seven fundamental methods of directly transforming other forms of energy into electrical energy:

Static electricity, from the physical separation and transport of charge (examples: triboelectric effect and lightning)
Electromagnetic induction, where an electrical generator, dynamo or alternator transforms kinetic energy (energy of motion) into electricity
Electrochemistry, the direct transformation of chemical energy into electricity, as in a battery, fuel cell or nerve impulse
Photoelectric effect, the transformation of light into electrical energy, as in solar cells
Thermoelectric effect, direct conversion of temperature differences to electricity, as in thermocouples, thermopiles, and Thermionic converters.
Piezoelectric effect, from the mechanical strain of electrically anisotropic molecules or crystals
Nuclear transformation, the creation and acceleration of charged particles (examples: betavoltaics or alpha particle emission)

Static electricity was the first form discovered and investigated, and the electrostatic generator is still used even in modern devices such as the Van de Graaff generator and MHD generators. Electrons are mechanically separated and transported to increase their electric potential.

Almost all commercial electrical generation is done using electromagnetic induction, in which mechanical energy forces an electrical generator to rotate. There are many different methods of developing the mechanical energy, including heat engines, hydro, wind and tidal power.

The direct conversion of nuclear energy to electricity by beta decay is used only on a small scale. In a full-size nuclear power plant, the heat of a nuclear reaction is used to run a heat engine. This drives a generator, which converts mechanical energy into electricity by magnetic induction.

Most electric generation is driven by heat engines. The combustion of fossil fuels supplies most of the heat to these engines, with a significant fraction from nuclear fission and some from renewable sources. The modern steam turbine invented by Sir Charles Parsons in 1884 - today generates about 80 percent of the electric power in the world using a variety of heat sources.

Turbines

All turbines are driven by a fluid acting as an intermediate energy carrier. Many of the heat engines just mentioned are turbines. Other types of turbines can be driven by wind or falling water.

Sources include:

Steam - Water is boiled by:
- Nuclear fission,
- The burning of fossil fuels (coal, natural gas, or petroleum). In hot gas (gas turbine), turbines are driven directly by gases produced by the combustion of natural gas or oil. Combined cycle gas turbine plants are driven by both steam and natural gas. They generate power by burning natural gas in a gas turbine and use residual heat to generate additional electricity from steam. These plants offer efficiencies of up to 60%.
- Renewables. The steam generated by:
  - Biomass
  - The sun as the heat source: solar parabolic troughs and solar power towers concentrate sunlight to heat a heat transfer fluid, which is then used to produce steam.
  - Geothermal power. Either steam under pressure emerges from the ground and drives a turbine or hot water evaporates a low boiling liquid to create vapour to drive a turbine.
Other renewable sources:
- Water (hydroelectric) - Turbine blades are acted upon by flowing water, produced by hydroelectric dams or tidal forces.
- Wind - Most wind turbines generate electricity from naturally occurring wind. Solar updraft towers use wind that is artificially produced inside the chimney by heating it with sunlight, and are more properly seen as forms of solar thermal energy.

Reciprocating engines

Small electricity generators are often powered by reciprocating engines burning diesel, biogas or natural gas. Diesel engines are often used for back up generation, usually at low voltages. However most large power grids also use diesel generators, originally provided as emergency back up for a specific facility such as a hospital, to feed power into the grid during certain circumstances. Biogas is often combusted where it is produced, such as a landfill or wastewater treatment plant, with a reciprocating engine or a microturbine, which is a small gas turbine.

Photovoltaic panels

Unlike the solar heat concentrators mentioned above, photovoltaic panels convert sunlight directly to electricity. Although sunlight is free and abundant, solar electricity is still usually more expensive to produce than large-scale mechanically generated power due to the cost of the panels. Low-efficiency silicon solar cells have been decreasing in cost and multijunction cells with close to 30% conversion efficiency are now commercially available. Over 40% efficiency has been demonstrated in experimental systems. Until recently, photovoltaics were most commonly used in remote sites where there is no access to a commercial power grid, or as a supplemental electricity source for individual homes and businesses. Recent advances in manufacturing efficiency and photovoltaic technology, combined with subsidies driven by environmental concerns, have dramatically accelerated the deployment of solar panels. Installed capacity is growing by 40% per year led by increases in Germany, Japan, California and New Jersey.

Other generation methods

Various other technologies have been studied and developed for power generation. Solid-state generation (without moving parts) is of particular interest in portable applications. This area is largely dominated by thermoelectric (TE) devices, though thermionic (TI) and thermophotovoltaic (TPV) systems have been developed as well. Typically, TE devices are used at lower temperatures than TI and TPV systems. Piezoelectric devices are used for power generation from mechanical strain, particularly in power harvesting. Betavoltaics are another type of solid-state power generator which produces electricity from radioactive decay. Fluid-based magnetohydrodynamic (MHD) power generation has been studied as a method for extracting electrical power from nuclear reactors and also from more conventional fuel combustion systems. Osmotic power finally is another possibility at places where salt and sweet water merges.

Electrochemical electricity generation is also important in portable and mobile applications. Currently, most electrochemical power comes from closed electrochemical cells ("batteries"), which are arguably utilized more as storage systems than generation systems, but open electrochemical systems, known as fuel cells, have been undergoing a great deal of research and development in the last few years. Fuel cells can be used to extract power either from natural fuels or from synthesized fuels (mainly electrolytic hydrogen) and so can be viewed as either generation systems or storage systems depending on their use.

List of Largest Power Plants in the World

noreply@blogger.com (Energetic) — Wed, 02 Jun 2010 16:46:00 +0000

The following page lists the largest power plants in the world in terms of current installed electrical capacity. Non-renewable power plants are those that run on coal, fuel oils and natural gas, while renewable power plants run on fuel sources such as biomass, geothermal heat, hydro, solar energy, solar heat, tides, waves and the wind. Only the most significant fuel source are listed for power stations that run on multiple sources.

At present, the largest power generating facility ever built is the Three Gorges Dam in China. The facility generates power by utilizing 32 turbines, each with a capacity of 700 MW. This totals the installed capacity to 22,500 MW, more than twice the installed capacity of the largest nuclear power station, the Kashiwazaki-Kariwa Nuclear Power Plant at 8,212 MW.

Although currently only a proposal, the Grand Inga Dam in Congo would surpass all existing power stations, including the Three Gorges Dam, if construction commences as planned in 2014. The design targets to top 39,000 MW in installed capacity, nearly twice that of the Three Gorges. This is nearly sufficient to meet the entire power demand of the African continent.

Non-renewable power plants

Largest Coal Power Plants

Rank	Station	Country	Capacity (MW)
1	Taichung Power Plant	Taiwan	5,780
2^A	Guodian Beilun Power Station	China	5,000
2^A	Waigaoqiao Power Station	China	5,000
4	Bełchatów Power Station	Poland	4,440
5	Zouxian Power Station	China	4,400

Largest Fuel oil Power Plants

Rank	Station	Country	Capacity (MW)
1	Surgut-2 Power Station	Russia	4,800
2	Kashima Power Station	Japan	4,400
3	Surgut-1 Power Station	Russia	3,280
4	Hirono Power Station	Japan	3,200
5	Ryazan Power Station	Russia	2,800

Largest Natural gas Power Plant

Rank	Station	Country	Capacity (MW)
1	Kawagoe Power Station	Japan	4,802
2	Chita Power Station	Japan	3,966
3^B	Kostromskaya Power Station	Russia	3,600
3^B	Sodegaura Power Station	Japan	3,600
5	Futtsu Power Station	Japan	3,520

Largest Nuclear Power Plants

Rank	Station	Country	Capacity (MW)
1	Kashiwazaki-Kariwa Nuclear Power Plant	Japan	8,212
2	Bruce Nuclear Generating Station	Canada	7,276
3	Ulchin Nuclear Power Plant	South Korea	5,881
4	Yeonggwang Nuclear Power Station	South Korea	5,875
5	Gravelines Nuclear Power Station	France	5,706

Largest Peat Power Plants

Rank	Station	Country	Capacity (MW)
1	Shatura Power Station	Russia	1,020
2	Kirov Power Station	Russia	300
3	Toppila Power Station	Finland	190
4	West Offaly Power Station	Republic of Ireland	150
5	Lough Ree Power Station	Republic of Ireland	100

Renewable power stations

Largest Biomass Power Plants

Rank	Station	Country	Capacity (MW)
1	Alholmens Kraft Power Station	Finland	265
2	Rumford Cogen Power Station	United States	102
3	Pécs Power Station	Hungary	65
4	Delano Power Station	United States	57
5	Stevens Croft Power Station	Scotland	52

Largest Geothermal Power Plants

Rank	Station	Country	Capacity (MW)
1	Cerro Prieto Geothermal Power Station	Mexico	720
2	Hellisheidi Power Station	Iceland	300
3	Wayang Windu Geothermal Power Station	Indonesia	227
4	Wairakei Power Station	New Zealand	181
5	Reykjanes Power Station	Iceland	150

Largest Hydroelectric Power Plants

Rank	Station	Country	Capacity (MW)
1	Three Gorges Dam	China	22,500
2	Itaipu Dam	Brazil - Paraguay	14,000
3	Guri Dam	Venezuela	10,200
4	Tucurui Dam	Brazil	8,370
5	Grand Coulee Dam	United States	6,809

Largest Photovoltaic Power Plants

Rank	Station	Country	Capacity (MW)
1	Olmedilla Photovoltaic Park	Spain	60
2	Strasskirchen Solar Park	Germany	54
3	Lieberose Photovoltaic Park	Germany	53
4	Puertollano Photovoltaic Park	Spain	50
5	Moura Photovoltaic Power Station	Portugal	42

Largest Solar thermal Power Plants

Rank	Station	Country	Capacity (MW)
1	Andasol Solar Power Station	Spain	100
2^C	SEGS VIII	United States	80
2^C	SEGS IX	United States	80
4	Nevada Solar One	United States	64
5	Alvarado I	Spain	50

Largest Tidal Power Plants

Rank	Station	Country	Capacity (MW)
1	Rance Tidal Power Station	France	240
2	Annapolis Royal Generating Station	Canada	20
3	Jiangxia Tidal Power Station	China	3.9
4	Kislaya Guba Tidal Power Station	Russia	1.7
N/A^D

Largest Wave Power Plant

Rank	Station	Country	Capacity (MW)
1	Agucadoura Wave Farm	Portugal	2.25
2	Islay Limpet	United Kingdom	0.5

Largest Wind Power Plants

Rank	Station	Country	Capacity (MW)
1	Roscoe Wind Farm	United States	782
2	Horse Hollow Wind Energy Center	United States	736
3	Tehachapi Pass Wind Farm	United States	705
4	Capricorn Ridge Wind Farm	United States	663
5	San Gorgonio Pass Wind Farm	United States	615

Cooling Tower

noreply@blogger.com (Energetic) — Mon, 26 Apr 2010 13:43:00 +0000

Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or rely solely on air to cool the working fluid to near the dry-bulb air temperature. Common applications include cooling the circulating water used in oil refineries, chemical plants, power plants and building cooling. The towers vary in size from small roof-top units to very large hyperboloid structures (as in Image 1) that can be up to 200 metres tall and 100 metres in diameter, or rectangular structures (as in Image 2) that can be over 40 metres tall and 80 metres long. Smaller towers are normally factory-built, while larger ones are constructed on site. They are often associated with nuclear power plants in popular culture.

A hyperboloid cooling tower was patented by Frederik van Iterson and Gerard Kuypers in 1918.

Classification by use

Cooling towers can generally be classified by use into either HVAC (air-conditioning) or industrial duty as suggested by Rantael, Rogellito and Stronghold, April in the book The Mystery of Cooling Towers Unfolded.

HVAC

An HVAC cooling tower is a subcategory rejecting heat from a chiller. Water-cooled chillers are normally more energy efficient than air-cooled chillers due to heat rejection to tower water at or near wet-bulb temperatures. Air-cooled chillers must reject heat at the dry-bulb temperature, and thus have a lower average reverse-Carnot cycle effectiveness. Large office buildings, hospitals, and schools typically use one or more cooling towers as part of their air conditioning systems. Generally, industrial cooling towers are much larger than HVAC towers.

HVAC use of a cooling tower pairs the cooling tower with a water-cooled chiller or water-cooled condenser. A ton of air-conditioning is the removal of 12,000 Btu/hour (3517 W). The equivalent ton on the cooling tower side actually rejects about 15,000 Btu/hour (4396 W) due to the heat-equivalent of the energy needed to drive the chiller's compressor. This equivalent ton is defined as the heat rejection in cooling 3 U.S. gallons/minute (1,500 pound/hour) of water 10 °F (5.56 °C), which amounts to 15,000 Btu/hour, or a chiller coefficient-of-performance (COP) of 4.0. This COP is equivalent to an energy efficiency ratio (EER) of 13.65.

Industrial cooling towers

Industrial cooling towers can be used to remove heat from various sources such as machinery or heated process material. The primary use of large, industrial cooling towers is to remove the heat absorbed in the circulating cooling water systems used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants, food processing plants, semi-conductor plants, and other industrial facilities. The circulation rate of cooling water in a typical 700 MW coal-fired power plant with a cooling tower amounts to about 71,600 cubic metres an hour (315,000 U.S. gallons per minute) and the circulating water requires a supply water make-up rate of perhaps 5 percent (i.e., 3,600 cubic metres an hour).

If that same plant had no cooling tower and used once-through cooling water, it would require about 100,000 cubic metres an hour ^[4] and that amount of water would have to be continuously returned to the ocean, lake or river from which it was obtained and continuously re-supplied to the plant. Furthermore, discharging large amounts of hot water may raise the temperature of the receiving river or lake to an unacceptable level for the local ecosystem. Elevated water temperatures can kill fish and other aquatic organisms. A cooling tower serves to dissipate the heat into the atmosphere instead and wind and air diffusion spreads the heat over a much larger area than hot water can distribute heat in a body of water. Some coal-fired and nuclear power plants located in coastal areas do make use of once-through ocean water. But even there, the offshore discharge water outlet requires very careful design to avoid environmental problems.

Petroleum refineries also have very large cooling tower systems. A typical large refinery processing 40,000 metric tonnes of crude oil per day (300,000 barrels per day) circulates about 80,000 cubic metres of water per hour through its cooling tower system.

The world's tallest cooling tower is the 200 metre tall cooling tower of Niederaussem Power Plant.

Cooling Tower Heat transfer methods

With respect to the heat transfer mechanism employed, the main types are:

Wet cooling towers or simply cooling towers operate on the principle of evaporation. The working fluid and the evaporated fluid (usually H₂O) are one and the same.
Dry coolers operate by heat transfer through a surface that separates the working fluid from ambient air, such as in a heat exchanger, utilizing convective heat transfer. They do not use evaporation.
Fluid coolers are hybrids that pass the working fluid through a tube bundle, upon which clean water is sprayed and a fan-induced draft applied. The resulting heat transfer performance is much closer to that of a wet cooling tower, with the advantage provided by a dry cooler of protecting the working fluid from environmental exposure.

In a wet cooling tower, the warm water can be cooled to a temperature lower than the ambient air dry-bulb temperature, if the air is relatively dry. As ambient air is drawn past a flow of water, evaporation occurs. Evaporation results in saturated air conditions, lowering the temperature of the water to the wet bulb air temperature, which is lower than the ambient dry bulb air temperature, the difference determined by the humidity of the ambient air.

To achieve better performance (more cooling), a medium called fill is used to increase the surface area between the air and water flows. Splash fill consists of material placed to interrupt the water flow causing splashing. Film fill is composed of thin sheets of material upon which the water flows. Both methods create increased surface area.

Air flow generation methods

With respect to drawing air through the tower, there are three types of cooling towers:

Natural draft, which utilizes buoyancy via a tall chimney. Warm, moist air naturally rises due to the density differential to the dry, cooler outside air. Warm moist air is less dense than drier air at the same pressure. This moist air buoyancy produces a current of air through the tower.
Mechanical draft, which uses power driven fan motors to force or draw air through the tower.
- Induced draft: A mechanical draft tower with a fan at the discharge which pulls air through tower. The fan induces hot moist air out the discharge. This produces low entering and high exiting air velocities, reducing the possibility of recirculation in which discharged air flows back into the air intake. This fan/fin arrangement is also known as draw-through. (see Image 2, 3)
- Forced draft: A mechanical draft tower with a blower type fan at the intake. The fan forces air into the tower, creating high entering and low exiting air velocities. The low exiting velocity is much more susceptible to recirculation. With the fan on the air intake, the fan is more susceptible to complications due to freezing conditions. Another disadvantage is that a forced draft design typically requires more motor horsepower than an equivalent induced draft design. The forced draft benefit is its ability to work with high static pressure. They can be installed in more confined spaces and even in some indoor situations. This fan/fill geometry is also known as blow-through. (see Image 4)
Fan assisted natural draft. A hybrid type that appears like a natural draft though airflow is assisted by a fan.

Hyperboloid (hyperbolic) cooling towers have become the design standard for all natural-draft cooling towers because of their structural strength and minimum usage of material. The hyperboloid shape also aids in accelerating the upward convective air flow, improving cooling efficiency. They are popularly associated with nuclear power plants. However, this association is misleading, as the same kind of cooling towers are often used at large coal-fired power plants as well. Similarly, not all nuclear power plants have cooling towers, instead cooling their heat exchangers with lake, river or ocean water.

Categorization by air-to-water flow

Crossflow

Crossflow is a design in which the air flow is directed perpendicular to the water flow (see diagram below). Air flow enters one or more vertical faces of the cooling tower to meet the fill material. Water flows (perpendicular to the air) through the fill by gravity. The air continues through the fill and thus past the water flow into an open plenum area. A distribution or hot water basin consisting of a deep pan with holes or nozzles in the bottom is utilized in a crossflow tower. Gravity distributes the water through the nozzles uniformly across the fill material.

Counterflow

In a counterflow design the air flow is directly opposite to the water flow (see diagram below). Air flow first enters an open area beneath the fill media and is then drawn up vertically. The water is sprayed through pressurized nozzles and flows downward through the fill, opposite to the air flow.

Common to both designs:

The interaction of the air and water flow allow a partial equalization and evaporation of water.
The air, now saturated with water vapor, is discharged from the cooling tower.
A collection or cold water basin is used to contain the water after its interaction with the air flow.

Both crossflow and counterflow designs can be used in natural draft and mechanical draft cooling towers.

Cooling tower as a flue gas stack

At some modern power plants, equipped with flue gas purification like the Power Station Staudinger Grosskrotzenburg and the Power Station Rostock, the cooling tower is also used as a flue gas stack (industrial chimney). At plants without flue gas purification, problems with corrosion may occur.

Wet cooling tower material balance

Quantitatively, the material balance around a wet, evaporative cooling tower system is governed by the operational variables of makeup flow rate, evaporation and windage losses, draw-off rate, and the concentration cycles:

M	= Make-up water in m³/h
C	= Circulating water in m³/h
D	= Draw-off water in m³/h
E	= Evaporated water in m³/h
W	= Windage loss of water in m³/h
X	= Concentration in ppmw (of any completely soluble salts … usually chlorides)
X_M	= Concentration of chlorides in make-up water (M), in ppmw
X_C	= Concentration of chlorides in circulating water (C), in ppmw
Cycles	= Cycles of concentration = X_C / X_M (dimensionless)
ppmw	= parts per million by weight

In the above sketch, water pumped from the tower basin is the cooling water routed through the process coolers and condensers in an industrial facility. The cool water absorbs heat from the hot process streams which need to be cooled or condensed, and the absorbed heat warms the circulating water (C). The warm water returns to the top of the cooling tower and trickles downward over the fill material inside the tower. As it trickles down, it contacts ambient air rising up through the tower either by natural draft or by forced draft using large fans in the tower. That contact causes a small amount of the water to be lost as windage (W) and some of the water (E) to evaporate. The heat required to evaporate the water is derived from the water itself, which cools the water back to the original basin water temperature and the water is then ready to recirculate. The evaporated water leaves its dissolved salts behind in the bulk of the water which has not been evaporated, thus raising the salt concentration in the circulating cooling water. To prevent the salt concentration of the water from becoming too high, a portion of the water is drawn off (D) for disposal. Fresh water makeup (M) is supplied to the tower basin to compensate for the loss of evaporated water, the windage loss water and the draw-off water.

A water balance around the entire system is:

M = E + D + W

Since the evaporated water (E) has no salts, a chloride balance around the system is:

M (X_M) = D (X_C) + W (X_C) = X_C (D + W)

and, therefore:

X_C / X_M = Cycles of concentration = M ÷ (D + W) = M ÷ (M – E) = 1 + [E ÷ (D + W)]

From a simplified heat balance around the cooling tower:

E = C · ΔT · c_p ÷ H_V

where:
H_V	= latent heat of vaporization of water = ca. 2260 kJ / kg
ΔT	= water temperature difference from tower top to tower bottom, in °C
c_p	= specific heat of water = ca. 4.184 kJ / (kg°C)

Windage (or drift) losses (W) from large-scale industrial cooling towers, in the absence of manufacturer's data, may be assumed to be:

W = 0.3 to 1.0 percent of C for a natural draft cooling tower without windage drift eliminators

W = 0.1 to 0.3 percent of C for an induced draft cooling tower without windage drift eliminators

W = about 0.005 percent of C (or less) if the cooling tower has windage drift eliminators

Cycles of concentration represents the accumulation of dissolved minerals in the recirculating cooling water. Draw-off (or blowdown) is used principally to control the buildup of these minerals.

The chemistry of the makeup water including the amount of dissolved minerals can vary widely. Makeup waters low in dissolved minerals such as those from surface water supplies (lakes, rivers etc.) tend to be aggressive to metals (corrosive). Makeup waters from ground water supplies (wells) are usually higher in minerals and tend to be scaling (deposit minerals). Increasing the amount of minerals present in the water by cycling can make water less aggressive to piping however excessive levels of minerals can cause scaling problems.

As the cycles of concentration increase the water may not be able to hold the minerals in solution. When the solubility of these minerals have been exceeded they can precipitate out as mineral solids and cause fouling and heat exchange problems in the cooling tower or the heat exchangers. The temperatures of the recirculating water, piping and heat exchange surfaces determine if and where minerals will precipitate from the recirculating water. Often a professional water treatment consultant will evaluate the makeup water and the operating conditions of the cooling tower and recommend an appropriate range for the cycles of concentration. The use of water treatment chemicals, pretreatment such as water softening, pH adjustment, and other techniques can affect the acceptable range of cycles of concentration.

Concentration cycles in the majority of cooling towers usually range from 3 to 7. In the United States the majority of water supplies are well waters and have significant levels of dissolved solids. On the other hand one of the largest water supplies, New York City, has a surface supply quite low in minerals and cooling towers in that city are often allowed to concentrate to 7 or more cycles of concentration.

Besides treating the circulating cooling water in large industrial cooling tower systems to minimize scaling and fouling, the water should be filtered and also be dosed with biocides and algaecides to prevent growths that could interfere with the continuous flow of the water. For closed loop evaporative towers, corrosion inhibitors may be used, but caution should be taken to meet local environmental regulations as some inhibitors use chromates.

Ambient conditions dictate the efficiency of any given tower due to the amount of water vapor the air is able to absorb and hold, as can be determined on a psychrometric chart.

Cooling Tower Operation In Freezing Weather

Cooling towers with malfunctions can freeze during very cold weather. Typically, freezing starts at the corners of a cooling tower with a reduced or absent heat load. Increased freezing conditions can create growing volumes of ice, resulting in increased structural loads. During the winter, some sites continuously operate cooling towers with 40 °F (4 °C) water leaving the tower. Basin heaters, tower draindown, and other freeze protection methods are often employed in cold climates.

Do not operate the tower unattended.
Do not operate the tower without a heat load. This can include basin heaters and heat trace. Basin heaters maintain the temperature of the water in the tower pan at an acceptable level. Heat trace is a resistive element that runs along water pipes located in cold climates to prevent freezing.
Maintain design water flow rate over the fill.
Manipulate airflow to maintain water temperature above freezing point.

Some commonly used terms in the cooling tower industry

Drift - Water droplets that are carried out of the cooling tower with the exhaust air. Drift droplets have the same concentration of impurities as the water entering the tower. The drift rate is typically reduced by employing baffle-like devices, called drift eliminators, through which the air must travel after leaving the fill and spray zones of the tower.
Blow-out - Water droplets blown out of the cooling tower by wind, generally at the air inlet openings. Water may also be lost, in the absence of wind, through splashing or misting. Devices such as wind screens, louvers, splash deflectors and water diverters are used to limit these losses.
Plume - The stream of saturated exhaust air leaving the cooling tower. The plume is visible when water vapor it contains condenses in contact with cooler ambient air, like the saturated air in one's breath fogs on a cold day. Under certain conditions, a cooling tower plume may present fogging or icing hazards to its surroundings. Note that the water evaporated in the cooling process is "pure" water, in contrast to the very small percentage of drift droplets or water blown out of the air inlets.
Blow-down - The portion of the circulating water flow that is removed in order to maintain the amount of dissolved solids and other impurities at an acceptable level. It may be noted that higher TDS (total dissolved solids) concentration in solution results in greater potential cooling tower efficiency. However the higher the TDS concentration, the greater the risk of scale, biological growth and corrosion.
Leaching - The loss of wood preservative chemicals by the washing action of the water flowing through a wood structure cooling tower.
Noise - Sound energy emitted by a cooling tower and heard (recorded) at a given distance and direction. The sound is generated by the impact of falling water, by the movement of air by fans, the fan blades moving in the structure, and the motors, gearboxes or drive belts.
Approach - The approach is the difference in temperature between the cooled-water temperature and the entering-air wet bulb temperature (twb). Since the cooling towers are based on the principles of evaporative cooling, the maximum cooling tower efficiency depends on the wet bulb temperature of the air. The wet-bulb temperature is a type of temperature measurement that reflects the physical properties of a system with a mixture of a gas and a vapor, usually air and water vapor
Range - The range is the temperature difference between the water inlet and water exit.
Fill - Inside the tower, fills are added to increase contact surface as well as contact time between air and water. Thus they provide better heat transfer. The efficiency of the tower also depends on them. There are two types of fills that may be used:
- Film type fill (causes water to spread into a thin film)
- Splash type fill (breaks up water and interrupts its vertical progress)

Fire hazards

Cooling towers which are constructed in whole or in part of combustible materials can support propagating internal fires. The resulting damage can be sufficiently severe to require the replacement of the entire cell or tower structure. For this reason, some codes and standards recommend combustible cooling towers be provided with an automatic fire sprinkler system. Fires can propagate internally within the tower structure during maintenance when the cell is not in operation (such as for maintenance or construction), and even when the tower is in operation, especially those of the induced-draft type because of the existence of relatively dry areas within the towers.

Stability

Being very large structures, they are susceptible to wind damage, and several spectacular failures have occurred in the past. At Ferrybridge power station on 1 November 1965, the station was the site of a major structural failure, when three of the cooling towers collapsed due to vibrations in 85mph winds. Although the structures had been built to withstand higher wind speeds, the shape of the cooling towers meant that westerly winds were funnelled into the towers themselves, creating a vortex. Three out of the original eight cooling towers were destroyed and the remaining five were severely damaged. The towers were rebuilt and all eight cooling towers were strengthened to tolerate adverse weather conditions. Building codes were changed to include improved structural support, and wind tunnel tests introduced to check tower structures and configuration.

Steam Turbine use in a Power Plant

noreply@blogger.com (Energetic) — Wed, 21 Apr 2010 17:51:00 +0000

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884.

It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher power-to-weight ratio. Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about 80% of all electricity generation in the world is by use of steam turbines. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process.

Types of Steam Turbine

Steam turbines are made in a variety of sizes ranging from small <1 style="font-size:130%;">

Steam Supply and Exhaust Condition
These types include condensing, noncondensing, reheat, extraction and induction.

Noncondensing or backpressure turbines are most widely used for process steam applications. The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. These are commonly found at refineries, district heating units, pulp and paper plants, and desalination facilities where large amounts of low pressure process steam are available.

Condensing turbines are most commonly found in electrical power plants. These turbines exhaust steam in a partially condensed state, typically of a quality near 90%, at a pressure well below atmospheric to a condenser.

Reheat turbines are also used almost exclusively in electrical power plants. In a reheat turbine, steam flow exits from a high pressure section of the turbine and is returned to the boiler where additional superheat is added. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion.

Extracting type turbines are common in all applications. In an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sent to boiler feedwater heaters to improve overall cycle efficiency. Extraction flows may be controlled with a valve, or left uncontrolled.

Induction turbines introduce low pressure steam at an intermediate stage to produce additional power.

Casing or Shaft Arrangements

These arrangements include single casing, tandem compound and cross compound turbines. Single casing units are the most basic style where a single casing and shaft are coupled to a generator. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A cross compound turbine is typically used for many large applications.

Principle of Operation and Design

An ideal steam turbine is considered to be an isentropic process, or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. No steam turbine is truly “isentropic”, however, with typical isentropic efficiencies ranging from 20%-90% based on the application of the turbine. The interior of a turbine comprises several sets of blades, or “buckets” as they are more commonly referred to. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

Turbine efficiency

To maximize turbine efficiency the steam is expanded, generating work, in a number of stages. These stages are characterized by how the energy is extracted from them and are known as either impulse or reaction turbines. Most steam turbines use a mixture of the reaction and impulse designs: each stage behaves as either one or the other, but the overall turbine uses both. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type.

Impulse turbines

An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage.

As the steam flows through the nozzle its pressure falls from inlet pressure to the exit pressure (atmospheric pressure, or more usually, the condenser vacuum). Due to this higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity. The steam leaving the moving blades is a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit velocity is commonly called the "carry over velocity" or "leaving loss".

Reaction turbines

In the reaction turbine, the rotor blades themselves are arranged to form convergent nozzles. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor.

Operation and Maintenance of Steam Turbine

When warming up a steam turbine for use, the main steam stop valves (after the boiler) have a bypass line to allow superheated steam to slowly bypass the valve and proceed to heat up the lines in the system along with the steam turbine. Also a turning gear is engaged when there is no steam to the turbine to slowly rotate the turbine to ensure even heating to prevent uneven expansion. After first rotating the turbine by the turning gear, allowing time for the rotor to assume a straight plane (no bowing), then the turning gear is disengaged and steam is admitted to the turbine, first to the astern blades then to the ahead blades slowly rotating the turbine at 10 to 15 RPM to slowly warm the turbine.

Problems with turbines are now rare and maintenance requirements are relatively small. Any imbalance of the rotor can lead to vibration, which in extreme cases can lead to a blade letting go and punching straight through the casing. It is, however, essential that the turbine be turned with dry steam. If water gets into the steam and is blasted onto the blades (moisture carryover) rapid impingement and erosion of the blades can occur, possibly leading to imbalance and catastrophic failure. Also, water entering the blades will likely result in the destruction of the thrust bearing for the turbine shaft. To prevent this, along with controls and baffles in the boilers to ensure high quality steam, condensate drains are installed in the steam piping leading to the turbine.

Speed regulation

The control of a turbine with a governor is essential, as turbines need to be run up slowly, to prevent damage while some applications (such as the generation of alternating current electricity) require precise speed control. Uncontrolled acceleration of the turbine rotor can lead to an overspeed trip, which causes the nozzle valves that control the flow of steam to the turbine to close. If this fails then the turbine may continue accelerating until it breaks apart, often spectacularly. Turbines are expensive to make, requiring precision manufacture and special quality materials. During normal operation in synchronization with the electricity net powerplants are governed with a five percent droop speed control . This means the full load speed is 100% and the no load speed is 105%. This is required for the stable operation of the net without hunting and dropouts of powerplants. Normally the changes in speed are minor . Adjustments in power output are made by slowly raising the droop curve by increasing the spring pressure on a centrifugal governor. Generally this is a basic system requirement for all powerplants because the older and newer plants have to be compatible in response to the instantaneous changes in frequency without depending on outside communication.

Direct drive

Electrical power plants use large steam turbines driving electric generators to produce most (about 80%) of the world's electricity. Most of these centralised stations are of two types, fossil fuel power plants and nuclear power plants, but some countries are using concentrating solar power (CSP) to create the steam. Steam turbines can also be used directly to drive large centrifugal pumps, such as feedwater pumps at a thermal power plant.

It has been proposed that, given sufficient solar energy, silicon might be refined for use as a coal replacement for this type of engine.

The turbines used for electric power generation are most often directly coupled to their generators. As the generators must rotate at constant synchronous speeds according to the frequency of the electric power system, the most common speeds are 3000 r/min for 50 Hz systems, and 3600 r/min for 60 Hz systems. In installations with high steam output, as may be found in nuclear power plant, the generator sets may be arranged to operate at half these speeds, but with four-pole generators.

Power Plant

noreply@blogger.com (Energetic) — Fri, 16 Apr 2010 15:07:00 +0000

A power plant is an industrial facility for the generation of electric power.

Power plant is also used to refer to the engine in ships, aircraft and other large vehicles. Some prefer to use the term energy center because it more accurately describes what the plants do, which is the conversion of other forms of energy, like chemical energy, gravitational potential energy or heat energy into electrical energy. However, power plant is the most common term in the U.S, while elsewhere power station and power plant are both widely used, power station prevailing in many Commonwealth countries and especially in the United Kingdom.

At the center of nearly all power plants is a generator, a rotating machine that converts mechanical energy into electrical energy by creating relative motion between a magnetic field and a conductor. The energy source harnessed to turn the generator varies widely. It depends chiefly on which fuels are easily available and on the types of technology that the power company has access to.

Thermal Power Plant

In thermal power plants, mechanical power is produced by a heat engine that transforms thermal energy, often from combustion of a fuel, into rotational energy. Most thermal power plants produce steam, and these are sometimes called steam power stations. Not all thermal energy can be transformed into mechanical power, according to the second law of thermodynamics. Therefore, there is always heat lost to the environment. If this loss is employed as useful heat, for industrial processes or district heating, the power plant is referred to as a cogeneration power plant or CHP (combined heat-and-power) plant. In countries where district heating is common, there are dedicated heat plants called heat-only boiler stations. An important class of power plants in the Middle East uses by-product heat for the desalination of water.

The efficiency of a steam turbine is limited by the maximum temperature of the steam produced and is not directly a function of the fuel used. For the same steam conditions, coal, nuclear and gas power plants all have the same theoretical efficiency. Overall, if a system is on constantly (base load) it will be more efficient than one that is used intermittently(peak load).

Besides use of reject heat for process or district heating, one way to improve overall efficiency of a power plant is to combine two different thrmodynamic cycles. Most commonly, exhaust gases from a gas turbine are used to generate steam for a boiler and steam turbine. The combination of a "top" cycle and a "bottom" cycle produces higher overall efficiency than either cycle can attain alone.

Classification of Power Plant
Thermal power plants are classified by the type of fuel and the type of prime mover installed.

Thermal Power Plant By Fuel

Nuclear power plants use a nuclear reactor's heat to operate a steam turbine generator. About 20% of electric generation in the USA is produced by nuclear power plants.
Fossil fuelled power plants may also use a steam turbine generator or in the case of natural gas fired plants may use a combustion turbine. A coal-fired power station produces electricity by burning coal to generate steam, and has the side-effect of producing a large amount of carbon dioxide, which is released from burning coal and contributes to global warming. About 50% of electric generation in the USA is produced by coal fired power plants
Geothermal power plants use steam extracted from hot underground rocks.
Renewable energy plants or
Biomass Fuelled Power Plants may be fuelled by waste from sugar cane, municipal solid waste, landfill methane, or other forms of biomass.
In integrated steel mills, blast furnace exhaust gas is a low-cost, although low-energy-density, fuel.
Waste to energy plants, heat from industrial processes is occasionally concentrated enough to use for power generation, usually in a steam boiler and turbine.
Solar thermal electric plants use sunlight to boil water, which turns the generator.

Thermal Power Plant By prime mover

Steam turbine plants use the dynamic pressure generated by expanding steam to turn the blades of a turbine. Almost all large non-hydro plants use this system. About 80% of all electric power produced in the world is by use of steam turbines.
Gas turbine plants use the dynamic pressure from flowing gases (air and combustion products) to directly operate the turbine. Natural-gas fuelled (and oil fueled) combustion turbine plants can start rapidly and so are used to supply "peak" energy during periods of high demand, though at higher cost than base-loaded plants. These may be comparatively small units, and sometimes completely unmanned, being remotely operated. This type was pioneered by the UK, Princetown being the world's first, commissioned in 1959.
Combined cycle plants have both a gas turbine fired by natural gas, and a steam boiler and steam turbine which use the hot exhaust gas from the gas turbine to produce electricity. This greatly increases the overall efficiency of the plant, and many new baseload power plants are combined cycle plants fired by natural gas.
Internal combustion Reciprocating engines are used to provide power for isolated communities and are frequently used for small cogeneration plants. Hospitals, office buildings, industrial plants, and other critical facilities also use them to provide backup power in case of a power outage. These are usually fuelled by diesel oil, heavy oil, natural gas and landfill gas.
Microturbines, Stirling engine and internal combustion reciprocating engines are low-cost solutions for using opportunity fuels, such as landfill gas, digester gas from water treatment plants and waste gas from oil production.

Cooling towers
Cooling towers evaporating water at Ratcliffe-on-Soar Power Station, United Kingdom.

All thermal power plants produce waste heat energy as a byproduct of the useful electrical energy produced. The amount of waste heat energy equals or exceeds the amount of electrical energy produced. Gas-fired power plants can achieve 50% conversion efficiency while coal and oil plants achieve around 30-49%. The waste heat produces a temperature rise in the atmosphere which is small compared to that of greenhouse-gas emissions from the same power plant. Natural draft wet cooling towers at nuclear power plants and at some large fossil fuel fired power plants use large hyperbolic chimney-like structures (as seen in the image at the left) that release the waste heat to the ambient atmosphere by the evaporation of water (lower left image). However, the mechanical induced-draft or forced-draft wet cooling towers (as seen in the image to the right) in many large thermal power plants, nuclear power plants, fossil fired power plants, petroleum refineries, petrochemical plants, geothermal, biomass and waste to energy plants use fans to provide air movement upward through downcoming water and are not hyperbolic chimney-like structures. The induced or forced-draft cooling towers are typically rectangular, box-like structures filled with a material that enhances the contacting of the upflowing air and the downflowing water.

In areas with restricted water use a dry cooling tower or radiator, directly air cooled, may be necessary, since the cost or environmental consequences of obtaining make-up water for evaporative cooling would be prohibitive. These have lower efficiency and higher energy consumption in fans than a wet, evaporative cooling tower.

Where economically and environmentally possible, electric companies prefer to use cooling water from the ocean, or a lake or river, or a cooling pond, instead of a cooling tower. This type of cooling can save the cost of a cooling tower and may have lower energy costs for pumping cooling water through the plant's heat exchangers. However, the waste heat can cause the temperature of the water to rise detectably. Power plants using natural bodies of water for cooling must be designed to prevent intake of organisms into the cooling cycle. A further environmental impact would be organisms that adapt to the warmer plant water and may be injured if the plant shuts down in cold weather.

In recent years, recycled wastewater, or grey water, has been used in cooling towers. The Calpine Riverside and the Calpine Fox power stations in Wisconsin as well as the Calpine Mankato power station in Minnesota are among these facilities.

Other sources of energy

Other power plants use the energy from wave or tidal motion , wind, sunlight or the energy of falling water, hydroelectricity. These types of energy sources are called renewable energy.

Hydroelectricity

Hydroelectric dams impound a reservoir of water and release it through one or more water turbines to generate electricity.

Pumped storage

A pumped storage hydroelectric power plant is a net consumer of energy but decreases the price of electricity. Water is pumped to a high reservoir when the demand, and price, for electricity is low. During hours of peak demand, when the price of electricity is high, the stored water is released through turbines to produce electric power.

Solar Power Plant

A solar photovoltaic power plant uses photovoltaic cells to convert sunlight into direct current electricity using the photoelectric effect. This type of plant does not use rotating machines for energy conversion.

Solar thermal power plants are another type of solar power plant. They use either parabolic troughs or heliostats to direct sunlight onto a pipe containing a heat transfer fluid, such as oil. The heated oil is then used to boil water into steam, which turns a turbine that drives an electrical generator. The central tower type of solar thermal power plant uses hundreds or thousands of mirrors, depending on size, to direct sunlight onto a receiver on top of a tower. Again, the heat is used to produce steam to turn turbines that drive electrical generators.

There is yet another type of solar thermal electric plant. The sunlight strikes the bottom of a water pond, warming the lowest layer of water which is prevented from rising by a salt gradient. A Rankine cycle engine exploits the temperature difference in the water layers to produce electricity.

Not many solar thermal electric plants have been built. Most of them can be found in the Mojave Desert of the United States although Sandia National Laboratory (again in the United States), Israel and Spain have also built a few plants.

Wind Power Plant

Wind turbines can be used to generate electricity in areas with strong, steady winds, sometimes offshore. Many different designs have been used in the past, but almost all modern turbines being produced today use a three-bladed, upwind design. Grid-connected wind turbines now being built are much larger than the units installed during the 1970s, and so produce power more cheaply and reliably than earlier models. With larger turbines (on the order of one megawatt), the blades move more slowly than older, smaller, units, which makes them less visually distracting and safer for airborne animals. Old turbines are still used at some wind farms, for example at Altamont Pass and Tehachapi Pass.