Gas Power PlantNTPC dadri (u.P.)By - Ayush SrivastavaB.Tech (EN) 4th year

Topics to be covered:IntroductionGas turbineGeneratorUnits ConfigurationStart-up And Applications of Gas Turbinescombined cycle processWaste heat recovery boiler(WHRB)Steam turbineAdvantages & Applications

NTPC Limited is an Indian PSU Public Sector Undertaking , engaged in the business of generation of electricity . The headquarters of the company is situated at New Delhi. NTPC's core business is generation and sale of electricity to state-owned power distribution companies and State Electricity Boards in India. The company also undertakes consultancy and turnkey project contracts that involve engineering, project management, construction management and operation and management of power plants.

NTPC is the largest power generation company of India with an electric power generating capacity of 47228 MW . A public sector company, it was incorporated in the year 1975 to accelerate power development in the country as a wholly owned company of the Government of India.15 coal based (24,395 MW), 7 gas based (3,955 MW)

History

The company was founded in November 1975 as "National Thermal Power Corporation Private Limited". It started work on its first thermal power project in 1976 at Shaktinagar (named National Thermal Power Corporation Private Limited Singrauli) in Uttar Pradesh.In the same year, its name was changed to "National Thermal Power Corporation Limited". In 1983, NTPC began commercial operations (of selling power) and earned profits of INR 4.5 crores in FY 1982-83. By the end of 1985, it had achieved power generation capacity of 2000 MW.

NTPC Dadri plant and township are property of ntpc ltd. and were built around 1988-1990.

NTPC Dadri is a unique power plant of NTPC group which has both coal based thermal plant and gas based thermal plant & it also comprises solar plant as well.

Toal capacity of coal plant is1820MW and gas plant is 817MW .

Solar plant is of 5 MW

Total power generated is 2642MW

NTPC DADRI

Coal plantStageUnit NumberInstalled Capacity (MW)Date of Commissioning1st12101991 October1st22101992 December1st32101993 March1st42101994 March2nd54902010 January2nd64902010 JulyTotalSix1820

The coal for the power plant is sourced from Piparwar Mines, Jharkhand.

Source of water for the power plant is Upper Ganga Canal.

Gas plantStageUnit NumberInstalled Capacity (MW)Date of CommissioningGT / ST1st1130.191992 MarchGT2130.191992 MayGT3130.191992 JuneGT4130.191992 NovemberGT5154.511993 FebruaryST6154.511993 MarchSTTotalSix829.78

The gas for the power plant is sourced from GAIL HBJ Pipeline, it also supports HSD as alternate fuel.

Source of water for the power plant is Upper Ganga Canal.

Solar Plant

Dadri solar plant started functioning from March 2013.

Its a 5 mega watt project .

On an average solar power plant generates 7.26 million units annually

It is covering an area of 27 acres .

Gas Plant

Components of gas plantCompressorTurbine ( Steam & Gas )Combustion chamberAlternatorPreheaterHeat recovery boiler

Parts of gas turbine

Motion of Compressor and Turbine

Flow of Air

Gas TurbineGas Turbine is a heat engineThe Process Includes:

Compression :Drawing air into the engine, pressurizing it, and then feeding it to the combustion chamber.Compresser consist of 16 stages , with curved blades .

Combustion :typically made up of a ring of fuel injectors that inject a steady stream of fuel into combustion chambers where it mixes with the air. The combustion produces a high temperature, high pressure gas stream that enters and expands through the turbine section.

Working Principle Brayton Cycle

1-2: Compression

2-3: Combustion

3-4: Expansion through Turbine and exhaust nozzle

4-1: Heat rejection to atmosphere

Simplified Prototype of Steam Turbines Working.

Courtesy:

Jacking oil is provider at the shaft of the turbine and alternator to reduce the friction .

Start-up of the GT is driven with the help of starting equipment which runs the generator as a motor with speed increasing from 0 to 600rpm. At this speed a pilot flame is ignited in the combustion chamber, fuel (gas/naphtha) enters and combustion takes place.Start-up of the GT

Start-up of the Gas TurbineThe speed increases further both with the help of generator motoring and the combustion of fuel up to about 2000 rpm. At this speed starting equipment is switched off and only the generator is made ready for synchronization with the grid. After synchronizations, the turbine load increases up to base load with more and more fuel entering the combustion chamber.

Working of Gas TurbineGas turbine basically operates in two types

Simple cycle operation ( open cycle )

Combined cycle operation ( closed cycle )

Simple Cycle Operation

A simple cycle operation turbine(SCCT) is a type ofgas turbinemost frequently used in the power generation, aviation (jet engine), and oil and gas industry (electricity generation and mechanical drives).

Combined Cycle OperationThe Combustion Turbine

Natural gas is mixed with air and burned in the combustion chamber to create the high pressure gasses needed to spin a turbine. This part of the plant is a single cycle, combustion turbine. These are sometimes called CTs. CTs are normally designed to meet peak loads.A combined cycle power plant is a dual cycle plant. The "2nd" part of the combined cycle is a heat recovery unit. It takes advantage of the energy in the exhaust gasses to create steam. The steam spins a steam turbine to generate additional electricity. The combined cycle plants are normally designed to meet base and intermediate loads.The Combined Cycle Plant

Gas turbine Steam turbineCombined operation

Heat Recovery Steam Generators

Waste Heat Recovery Boiler(WHRB)Heat Recovery Steam Generators (HRSG) have found application in a wide range of industries where the cogeneration of steam and electricity is required, in order to obtain an independent power plant and negligible emission levels.

Heat Recovery Steam Generator

Control Room

SCAD system is used for controlling as well as monitoring .Three CPUs were used in parallel to send current and recorded data.

Switch Yard

Switch yard consist of huge size transformers and a number of circuit-breakrs .

It is basically for switching of supply for transmission .

Conclusion Gas turbine power plants can be started up and run at full capacity in only 10 to 20 minutes, making them well suited as backup plants for utility companies that require additional electricity immediately.

Gas turbine systems also require much less water than steam power plants, and they are easily converted into combined cycle power plants, which are much more efficient.

DisadvantagesThe power needed to drive the compressor reduces the net outputs, consuming more fuel to do the same amount of work.

The operating temperature in gas turbines is higher than in other power plant systems and can shorten the lifespan of some of the system components

The efficiency level of gas turbine plants are lower than those of other types of power plants.

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ApplicationsGas turbine power plants are used to supply peak loads in steam or hydro-plants.

They are used as standby plants for hydro-electric power plants.

Gas turbines are used in jet, aircraft and ships.

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