REPORT ON INDUSTRIAL VISIT TO GAS POWER PLANT AT URAN
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ACKNOWLEDGMENT
We would give to say our great sincere thanks towards our guide Mrs. Jeesha Satheesh for introducing the subject & allow us to do our project in field of power plant engineering. Her constant guidance support and encouragement contributes very much in our efforts for completing this project. We would like to express our gratitude towards our head of department Mr. M. V. Bhatkar for his support and encouragement towards us. We want to take this opportunity to give our thanks to EESA head and all those who have engaged in this committee an all the members and of course batch member’s discussion with them helped us to and many concept. Lastly we want thanks to them who helped us directly to complete this report.
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Uran Gas Turbine Power Station
1. Postal Address of the Office/Power Station (Phone No. /Fax No.) Office of the Chief General Manager, Gas Turbine Power Station, and Uran At/Post: Bokadvira, Tal: Uran, District - Raigad. Pin-400 702, (Maharashtra State) India Phone: (022) 27222285, Fax: 0091-22-27221157 Gram:"Powergrid, Uran", Email:
[email protected]
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Uran Location: Maharashtra Operator : Maharashtra State Power Generation Co Ltd Configuration: 4 X 60 MW V93 GT (Unit-1 scrapped 2003), 2 X 336MW, 2+1 CCGT blocks withV94.2 gas turbines
Fuel: natural gas, oil Operation: 1982-1994 HRSG supplier: Deutsche Babcock T/G supplier: Siemens
EPC: Siemens, Lahmeyer, Tata Quick facts: Uran power station is near Bokadvira Village, 1km away from Uran town and 55Km from Mumbai by road. The site is surrounded on three side by the Arabian Sea. Uran cost about Rs 1,118.5 Crores. Grid connection is by 4 X 220Kv lines to Apta S/S and 2 X 220kV lines to Kharghar S/S.
Commissioning Date. Unit
Capacity (MW)
Date
2
60
29/03/82
3
60
26/05/82
4
60
21/07/82
5
108
10/10/85
6
108
02/08/85
7
108
17/06/85
8
108
15/01/86
A0
120
11/03/94
B0
120
28/10/94
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Performance Unit-wise Generation (Since commissioning) Gen.
Gen. Gen. MUs
Details
Gen. MUs
Gen. MUs
Gen. MUs
Gen. MUs
Gen. MUs
Gen. MUs
MUs
Units
UNIT-I
81-82
1.888
Gen. MUs
0.037
Total
Gen.
MUs
MUs
Total
Station
Gen. MUs
MUs
UNIT- UNIT- UNIT- UNIT- UNIT- UNIT- UNITII III IV V VI VII VIII
Gen.
UNIT- UNITA0 B0
1.925
1.925
82-83
283.783 266.722 264.173 246.951
1061.629
1061.629
83-84
380.333
412.82 397.226 404.147
1594.526
1594.526
84-85
298.077 362.856 219.769 414.282
1294.984
1294.984
85-86
199.146
133.62 186.135 33.365
48.806 1129.473
1129.473
86-87
54.336
96.169
23.483 285.226 527.416 498.152 544.065 553.07 2581.917
2581.917
87-88
25.06
254.451 303.124 143.671
68.992 203.529 255.88
2561.618
2561.618
88-89
204.205 214.376 163.609 179.774 234.111 484.342 81.763 360.785 1922.965
1922.965
89-90
241.368
715.605 159.55 2474.591
2474.591
90-91
70.213
601.51 633.668 562.243 2732.475
2732.475
91-92
0
315.241 199.815 333.46 566.768 543.188 408.467 552.806 2919.745
2919.745
92-93
0
299.961 288.573 209.975 414.597 360.103 533.505 513.134 2619.848
2619.848
93-94
503.5
71.326 380.025 216.927 613.81 0
242.634 247.207
159.279 169.986 276.393
0
375
517.067 370.545
75.98
444.2
195.627 202.543 532.461 189.234 1725.523
1.602
1.602
1727.125
94-95
3.871
58.447 207.634 58.885 760.023 600.891 649.829 599.641 2939.221 516.341 204.398 720.739
95-96
0
267.997 171.226 210.788 688.397 792.801 583.248 709.897 3424.354 739.614 711.096 1450.71 4875.064
96-97
0
162.065 154.624 155.974 884.189 738.083 750.575 465.167 3310.677 874.75 282.905 1157.655 4468.332
97-98
0
104.179 129.696 132.771 738.731 747.644 805.238 741.346 3399.605 774.938 829.276 1604.214 5003.819
98-99
0
105.421 118.878 18.917 832.948 799.313 757.988 749.906 3383.371 885.338 840.146 1725.484 5108.855
99-00
0
39.222
26.692
1.465
00-01
0
17.668
30.382
0.013
01-02
0
65.546
73.966
5.676
02-03
0
15.03
45.561
11.429 732.818 858.701 469.188 431.378 2564.105 822.487 504.576 1327.063 3891.168
03-04
Scrapped
6.817
38.962
37.115 712.433 686.42 681.778 517.282 2680.807 702.74 622.684 1325.424 4006.231
04-05
Scrapped
0.679
17.95
3.402
547.743 821.489 647.459 629.801 2668.523 714.254 732.392 1446.646 4115.169
05-06
Scrapped 12.211
30.701
3.677
660.362 665.357 486.519 600.353 2459.18 697.142 621.17 1318.312 3777.492
06-07
Scrapped
0.894
1.436
689.397 855.751 581.677 463.04 2599.869 839.176 588.841 1428.017 4027.886
7.674
632.974 703.86 705.2
3659.96
581.31 569.679 2555.202 736.462 643.986 1380.448 3935.65
640.378 289.909 575.42
2258.97 751.957 462.197 1214.154 3473.124
644.299 558.979 518.582 569.639 2436.687 638.269 616.794 1255.063 3691.75
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1. INTRODUCTION Probably a windmill was that first turbine to produce useful work, wherein there is no pre compression and no combustion. The characteristic features of a gas turbine as we think of the name today include a compression process and a heat addition process.
The gas turbine represent perhaps the most satisfactory way of producing large amount of power in very small area. The efficiency of gas turbine is 20 to 30 % which is improved by installing steam power plant with gas plant (combine plant) to 45% or more. Same case is accrue in Uran gas plant initially only gas plant are installed the capacity is 4 X 60 MW V93 GT and due to some reasons one of them was scrapped in 2003 and before few days combine cycle plant are installed the capacity is 2+1 CCGT blocks withV94.2 gas turbines. The total capacity of plant right now is 792MW. The main advantages for Uran gas power plant is that , the some amount of fuel gas is obtain from Bombay high it menace some amount of gas is obtain from nearest site only as well as due to excessive amount of gas production the gas agencies burnt the gas in atmosphere so this gas is utilized to generate the electricity where there is a shortage is created of electricity. And remaining fuel is imported from Oman. 6
2. The Gas Turbine Advantage Since the no equipment used in gas plant is less compare to thermal plant, the capital cost considerably less. As well as the space requirement by machinery is less. ►
The vibration created by gas turbine is less because of perfect balancing of turbine blades, so the losses accrue by vibration is very less which give higher mechanical efficiency. ►
The pollution created by plant is very less compare to thermal plant, because the ash is absent in power production process as well as the carbon emission is very less. Carbon emission by different plant is shown in graph bellow. In the graph, carbon emission by gas plant is comparatively less. ►
The site of the steam plant is dictated by the availability of large cooling water where as an open cycle gas turbine plant can be located near the load center as no cooling water is required. The cooling water required for close cycle gas turbine is hardly 10% of the steam plant. ►
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The gas power plant can work quit economically for short running hours because steam plant required 3-4 days to start and gas plant required 1 day to start. ►
►Since
the gas turbine fuel is easily gasified and liquefied, the storage of fuel is much smaller and handling is easy.
►Gas
turbines plant can be built relatively quicker. They required much less space and civil engineering works and water supply. The gas turbine plants can be installed at selected load center as space requirement is considerably less where steam plant cannot be accommodate. ►
Above 550°C, the thermal efficiency of the gas turbine plant increases three times as fast the steam cycle efficiency for a given top temperature increase. ►
3. Disadvantages ►
Poor part load efficiency.
Since the turbine parts are subjected to extremely high temperature special metals and alloy are required for different component of the plants. ►
The temperature at turbine blades is too much high so special cooling method are required for cooling the turbine blades. ►
The rate of wear and tear of turbines is too much high therefore it has small operating life as well as it require high maintenance.7 ►
It require some external rotating energy to start up the compressor. In Uran gas plant one diesel generator set (DG set) is installed. ►
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4. Reasons to install the plant in Uran
As we know the plant should be located near to load center to avoid transmission costs and losses. Here Uran plant is located near to Apta substation as well as Kharghar substation so transmission cost is decreases and transmission efficiency increases. ►
The population in Uran especially near to the plant site is very less as well as there is no business center is located near to plant. We can say that the plant is located in remote place. ►
Uran is surrounded on three sides by Arabian Sea so fuel transportation is very easy and cheap as well as gas is alredy installed between Bombay high and Uran plant. ►
The local people of Uran are easily available as labours at low salaries. ►
Uran is 55Km from Mumbai by road as well as it is located near to Mumbai-Pune highway. So transportation of auxiliaries will be easy and more economical. ►
The cost of land in Uran is 2000Rs/sq.ft (approx) which is very low compare to any other place in harbor side. ►
The bearing capacity of the land in Uran is high, because the land is quit rocky. ►
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5. Different auxiliaries use in gas plants
For open cycle plant ►
Gas Turbine
►
Compressor
►
Combustor
►
Intercoolers
►
Regenerator
For combine cycle plant ►
Gas turbine
►
Compressor
►
Combustor
►
Intercooler & Regenerator
►
Heat exchanger
►
Steam turbine
►
Condenser & Cooling tower
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6. Component of combine cycle plant 6.1 Gas turbine A turbine is any kind of spinning device that uses the action of a fluid to produce work. Typical fluids are: air, wind, water, steam and helium. The first practical gas turbine used to generate electricity ran at Neuchatel, Switzerland in 1939, and was developed by the Brown Boveri Company.
A land-based open cycle gas turbine
The name "gas turbine" is somewhat misleading, because to many it implies a turbine engine that uses gas as its fuel. Actually a gas turbine (as shown schematically in above fig) has a compressor to draw in and compress gas (most usually air); a combustor (or burner) to add fuel to heat the compressed air; and a turbine to extract power from the hot air flow. There have been a profusion of "other names" for the gas turbine. For electrical power generation application it is generally called a gas turbine, also a combustion turbine (CT), a turbo shaft engine, and sometimes a gas turbine engine. For aviation applications it is usually called a jet engine, and various other names depending on the particular engine configuration or 11
application, such as: jet turbine engine; turbojet; turbofan; fanjet; and turboprop or prop jet (if it is used to drive a propeller). A turbine basically employs vanes or blades mounted on shaft and enclosed in a casing. The flow of fluid through the turbine in most design in axial and tangential to the rotor at nearly constant or increasing radius. The turbine employs in Uran gas plant are made from “CRAFT WORK UNION GERMANY” The basic requirement of turbine is: ► Light weight. ► High efficiency. ► Reliability in operation. ► Long working life. More stage of the turbine is always proffered in gas turbine power plant because it helps to reduce the stresses. In the blades and increases the overall life of the turbine. The following accessories are fitted to the turbine. Tachometer. ► An over speed governor. ► Lubricating oil pump ► Starting motor or engine (in Uran diesel engine is employs) ► Starting set up gears ► Oil cooler ► Filter ► Inlet & exhaust muffler ►
Gas turbine blades
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6.2 Compressor A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible, while some can be compressed, the main action of a pump is to pressurize and transport liquids.
Compressor is classified as follow
In gas turbine power plant generally following compressor are used ► Centrifugal type compressor ► Axial flow type compressor 13
6.2.1 Centrifugal type compressor The centrifugal compressor consists of an impeller and a diffuser. The impeller imparts the high kinetic energy to the air and diffuser converts the kinetic energy in the pressure energy. The pressure ratio of 2 to 3 is possible with single stage compressor an it can be increased up to 20 with 3-stage compressor.
In above diagram one compressor and one prime mover unit is displayed. Here prime mover is nothing but a gas turbine which indicate by red color and another unit is compressor which indicated by blue color. Due to prime mover rotation compressor also start rotating and it starts taking the air from it’s inlet (compressor ambient air inlet) and compress the air in very small volume (compressor housing in fig.) And fed this compressed air for further application through its outlet. In the centrifugal compressor Capacity varies directly as the speed ratio. ► Total pressure varies as the speed of the square ratio. ► Power input varies as the cube of the speed ratio. ► Pressure is developed independent of load, but the volume depends On the load. ►
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6.2.2 Axial flow compressor The axial flow compressor is commonly used in gas turbine installation. As axial flow compressor consist of a series of rotor and stator stages with decreasing diameter along the flow of air. The rotor blades are fixed on the rotor and rotor are fixed in shaft. The stator blades are fixed on stator in the following figure the upper and down part are stator blades and its housing and middle part is rotor blades and shaft
The stator blades guide the air flow to the next rotor stage coming from the previous rotor stage. The air flow along the axis of the rotor. The kinetic energy is given to the air as it passes through the rotor and parts of it are converted in to pressure. An axial compressor is capable of delivering constant volumes of air over varying discharge pressure. This of machine are very useful where constant pressure is require for variable load like gas power plant.
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6.2.3 Combustor Combustor is a place where the compressed air and gas are mixed up and finally fired. The primary function of the combustor is to provide for chemical reaction of fuel and air being supplied by the compressor
Above diagram shows the arrangement of combustor and compressor. The compresed air is fed to combustion chamber (combustor). Here in combustor the fuel (gas) is injected from nozzle and some igniting arrangement is provided, due to this ignition, the mixture is catching the fire (action like blast is accrue). These forces of blast is directly acted upon the turbine blade and due to this force turbine start rotating. The flow of hot air is called as thrust. The turbine is mechanically coupled with compressor which is passed through combustor. It must fulfill following condition The pressure losses must be low. ► Carbon deposition must not be formed in any condition. ► Flame propagation. ► No fuel is remaining after the burning. ►
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6.2.4 Intercooler In the gas turbine plant the intercooler is generally used when the pressure ratio used is sufficiently large and compression is completed with two or more stages. The cooling of compressed air is generally done with the use of cooling water
6.2.5 Regenerators In the regenerator heat transfer takes place between the exhaust gases and cool air. It is usually made in shell and tube construction with gas flowing inside the tubes and air outside the tubes. Here red flow indicate flow of hot gas and blue flow indicate the flow of cool air.
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6.2.6 Heat exchanger & steam turbine This auxiliary are generally found in combine cycle power plant. Where the west heat develops by gas turbine is reused to boil the water or making the steam. The transferring of heat from hot gas to water is carried out in heat exchanger. Heat exchanger have tubes which is merge in water tank and gas is passed through tubes so water will gates heated up and finally steam is obtained from upper side.
6.2.7 Steam turbine 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.
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6.2.8 Air cooled condenser
In Uran gas plant air cooled condenser is employs to condense the steam. In Uran due to shortage of cooling water, the cooled condenser is installed. As well as plant is situated near to sea so air is humid compare to any other place and therefore cooling tower are effectively works. Uran gas plant the startup of fan of cooling system can be carried out by gear system. Due to wear and tear this gear system is replaced by variable frequency drive (VFDs).
Air cooled condenser
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7. Classification of gas power plant Open cycle gas plant. ► Close cycle gas plant. ► Combine cycle gas plant. (Uran gas plant is combine cycle plant ) ►
7.1 Open cycle gas plant. In this type of plant the cycle of fluid is not completed. in it air is taken and smoke or waste product is exhausted. Here air is taken from atmosphere. And it compressed by compressor and fired in combustor. This mixture is used to rotate the turbine and finally the hot air(waste gas) Is liberated in atmosphere. It is also called as simple cycle plant.
7.2 Close cycle plant In this type of plant, fuel is not directly burning with air but air is used again and again. In it air is compressed and burnt in compressor and combustor respectively. And finally due to this air, turbine starts rotating. Instead of liberating the gas in atmosphere, it will be cool down and reused again and again.
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7.3 Combine cycle power plant A combined cycle is characteristic of a power producing engine or plant that employs more than one thermodynamic cycle. Heat engines are only able to use a portion of the energy their fuel generates (usually less than 50%). The remaining heat (e.g., hot exhaust fumes) from combustion is generally wasted. Combining two or more thermodynamic cycles, such as the Brayton cycle and Rankine cycle, results in improved overall efficiency. In combine cycle power plant, a gas turbine generator generates electricity and the waste heat is used to make steam to generate additional electricity via a steam turbine, this last step enhances the efficiency of electricity generation.
An open circuit gas turbine cycle has a compressor, a combustor and a turbine. For gas turbines the amount of metal that must withstand the high temperatures and pressures is small, and lower quantities of expensive materials can be used. In this type of cycle, the input temperature to the turbine (the firing temperature), is relatively high (900 to 1,400 °C). 21
The output temperature of the flue gas is also high. This is therefore high enough to provide heat for a second cycle which uses steam as the working fluid.
Uran gas plant is one of the examples of combine cycle power plant. In Uran gas plant, pair of 2 gas unit is fed their heat to 2 appropriate boilers and the steam of both the boiler is fed to 1 steam turbine. This is one unit, there are one more unit like this.
Advantages of combine cycle plant Improved efficiency ► More suitable for rapid start and shutdown ► Less cooling water is required ► Combine system offers self-sustaining features ►
Working principal of combine cycle plant
In combine cycle plant the atmospheric air is compressed by compressor. This compressed air is now fed to combustor, in combustor gas is mixed with compressed air and this mixture is ignited so high temperature thrust is produce, this thrust is use to rotate the gas turbine, now high temperature waste product is fed to heat exchanger, in heat exchanger this waste heat is utilized for making the steam. This high pressure steam is fed to steam turbine and finally power is developed (from gas as well as steam turbine). Then the steam is condensed and cool down and reused.
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