RU2273740C1 - Method of operation of gas-steam thermoelectric plant - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: according to proposed method of operation of gas-steam thermoelectric plant, atmospheric air is compressed in compressor and fuel is combustion in said air, useful work of high-pressure turbine is used for compressing the air, useful work of low-pressure turbine is used to drive electric generator and generate power. Heat of waste steam-gas mixture is recovered for generation of superheated steam. Superheated steam is expanded in counterpressure steam turbine whose useful work is used for generation of power, and "ecological" steam expanded in counterpressure steam turbine is fed to combustion products coming out of high-pressure gas turbine, and "power generating: steam is fed into fuel burning zone of additional combustion chamber.

EFFECT: increased power and improved economy of gas-steam thermoelectric plant, possibility of use of existing gas and steam turbines with standard parameters of steam for creating said thermoelectric plant.

2 dwg

Description

The method of operation of a gas-steam cogeneration plant belongs to the field of energy.

There is a known method of operation of the Aquarius gas-steam installation, according to which atmospheric air is compressed in a compressor, fuel is burned in it, and "ecological" and "energy" steam flows are fed into the combustion products. The gas-vapor mixture is sequentially expanded in high and low pressure turbines, the useful work of high pressure turbines is used to compress air in the compressor, low pressure turbines are used to drive an electric generator and generate electricity. (Catalog of gas-turbine equipment "Gas-turbine technologies", 2003 - 2004, p. 173, 174, Fig. 16).

The heat of the gas-vapor mixture after the low-pressure gas turbine is utilized to generate superheated steam, which is used for injection into compressed air after the compressor and into the fuel combustion zone. Due to the "ecological" injection of steam into compressed air, the formation of nitrogen oxides in the combustion products is reduced, the "energy" injection of steam provides an increase in the power of high and low pressure combined-cycle turbines. Cooling water with a temperature of 20-30 ° С is injected into a gas-vapor mixture cooled during steam generation and the steam component of the gas-vapor mixture is condensed, a mixture of steam condensate and irrigation water is separated and steam condensate is separated, and the products of fuel combustion are vented to the atmosphere.

The separated water is divided into two streams, a smaller stream is used as feed water to generate steam when utilizing the heat of the steam-gas mixture spent in the turbines, the larger stream is cooled in a heat exchange unit and fed for injection into the gas-vapor mixture. The heat of a larger stream of separated water is diverted to the cooling system, and can also be used to heat make-up water or heating network water.

The closest in technical essence is the method of operation of a contact-type gas-steam heat and power plant with steam injection into a combustion chamber and a heat pump installation (Catalog of gas-turbine equipment "Gas-turbine technologies", 2003-2004, pp. 173, 174, Fig. 17., Combined-cycle plant PGU-60S. Commercial offer. FSUE "Salyut", 2005. ").

According to this method, atmospheric air is compressed in a compressor and fuel is burned in it, and "ecological" and "energy" steam flows are supplied to the fuel combustion products. The resulting vapor-gas mixture is successively expanded in high and low pressure turbines, the useful work of high pressure turbines is used to compress air in the compressor, and low pressure turbines are used to drive an electric generator and generate electricity.

The heat of the vapor-gas mixture after the low-pressure gas turbine is utilized to generate superheated steam. The resulting superheated steam is expanded in a counter-pressure steam turbine, the useful work of which is used to generate electricity. The exhaust steam is used for "environmental" injection into compressed air after the compressor and "energy" injection into the fuel combustion zone. Irrigation water with a temperature of 20-30 ° C is injected into the vapor-gas mixture cooled during steam generation and the vapor component of the vapor-gas mixture is condensed, the resulting mixture is separated steam condensate and irrigation water and separate it from the products of fuel combustion, followed by discharge of the latter into the atmosphere.

The separated water is divided into two streams, a smaller stream is used as feed water to generate steam, and the heat of the larger stream is used in a heat pump unit to heat the heating water of the heating system. The larger flow of separated water cooled in this case is supplied as irrigation water for injection into the vapor-gas mixture partially cooled during steam generation.

With the described method of operation of a gas-steam combined heat and power plant, they increase the thermal efficiency of the combined heat and power plant by utilizing the heat of the steam component of the steam-gas mixture and using it to heat the heating network water, increase the specific useful work and power of the gas part of the gas-steam combined heat and power plant, and provide a low concentration of harmful substances in the flue gases.

The superheated steam generated during the utilization of the heat of the spent steam-gas mixture is used for expansion in a backpressure steam turbine with its subsequent injection into the high-pressure combustion chamber of a steam-gas turbine.

In the described method, steam is injected in front of the high-pressure steam-gas turbine, in addition, due to the reduced parameters (6-7 MPa, 450-500 ° C) and the increased pressure of the steam supplied to the injection (2-3 MPa), the applied backpressure steam turbine installation will be have non-standard parameters and low electrical power. As a result, this method does not allow the use of existing gas and steam turbines when creating a contact-type gas-steam heat and power plant.

The objective of the proposed technical solution is to develop a method of operation of a gas-steam combined heat and power plant, which allows to increase its power and efficiency and use existing gas and steam turbines with standard steam parameters when creating it.

The problem is solved by the method of operation of a gas-steam heat and power plant, according to which atmospheric air is compressed in a compressor and fuel is burned in it, useful work of high-pressure turbines is used to compress air, and low-pressure turbines are used to drive an electric generator and generate electricity; the heat of the spent vapor-gas mixture is utilized to generate superheated steam, the superheated steam is expanded in a counter-pressure steam turbine, the useful work of which is used to generate electricity, while the "ecological" steam expanded in the counter-pressure steam turbine is fed to the combustion products leaving the high-pressure gas turbine, and "energy" steam is fed into the fuel combustion zone of an additional combustion chamber.

The use of an additional fuel supply between gas turbines of high and low pressure in the gas-steam combined heat and power plant and injection of "energy" steam expanded in the backpressure steam turbine into the combustion products allows increasing the electric and thermal power of the gas-steam combined heat and power plant.

The supply of “ecological” steam to the combustion products leaving the high-pressure turbine, which expanded in the backpressure steam turbine, allows the formation of nitrogen oxides in the gases discharged into the atmosphere to be reduced.

Increasing the temperature and flow rate of the gas-vapor mixture spent in the low-pressure gas-turbine allows the generation of high-pressure steam of standard parameters during heat recovery of the gas-vapor mixture, increasing the power of the backpressure steam turbine, as well as the power and efficiency of the gas-steam combined heat and power plant.

The proposed set of features is new and allows the use of existing counterpressure steam turbines and turbochargers of existing gas turbine units with a split shaft in a gas-steam heat and power plant, while significantly reducing the cost of creating such a gas-steam heat and power plant.

The drawings explain the proposed method of operation of a gas-steam combined heat and power plant: in Fig. 1, a block diagram is shown, in Fig. 2 its circuit diagram is shown.

The block diagram of figure 1 consists of three blocks: gas-steam turbine block 1; heat recovery unit of the gas-vapor mixture 2; unit for using the heat of separated water 3.

Figure 2 shows a schematic diagram of a gas-steam cogeneration plant for implementing the proposed method.

The gas-steam turbine unit 1 includes: an air compressor 4, a high-pressure combustion chamber 5, a high-pressure gas turbine 6 (compressor turbine), an afterburner 7 with an injection device 8, a low-pressure gas and steam turbine 9 (free power turbine), an electric generator 10, a backpressure steam turbine 11, the steam line of the “energy” 12 and the “ecological” steam 13, the superheated steam pipeline 14, the gas-vapor mixture pipeline 15.

The heat recovery unit of the gas-vapor mixture 2 includes: a steam boiler - utilizer 16, comprising a superheater 17, an evaporator 18, a water economizer 19, a gas-water heater 20, an irrigation device 21, a gas cooler-condenser 22 with a separation device, an exhaust gas duct 23 with a smoke exhauster, a separated water pipeline 24, pipelines direct 32 and return 33 network water heating system.

Block 3 of using the heat of separated water includes: a tank of separated water 25, an irrigation water pipe 26, a feed water pipe 27 of a recovery boiler 16 with a feed pump, a softening filter and a feed water deaerator 28, a heat pump installation 29, network water pipes 30 and 31.

The proposed method of operation of a gas-steam cogeneration plant is as follows. Atmospheric air is compressed by a compressor 4 of a gas-steam-turbine unit 1, directed to a high-pressure combustion chamber 5, and fuel is burned therein.

The combustion products of the fuel are sequentially expanded in high-pressure and low-pressure turbines 9. The high-pressure gas turbine 6 of the gas-steam turbine unit 1 operates on the products of the combustion of fuel leaving the main combustion chamber 5.

The useful work of a high-pressure gas turbine 6 is used to compress the air in the compressor 4. To the products of fuel combustion spent in a high-pressure gas turbine 6, "ecological" steam is supplied from the backpressure steam turbine 11 through the steam line 13, using it for injection into the combustion products leaving high pressure turbines 6. Fuel is supplied to the additional afterburner 7. In the injection device 8 of the additional afterburner 7 through the steam line 12 serves "energy" steam flow.

The temperature of the resulting vapor-gas mixture at the inlet to the uncooled gas-vapor turbine 9 is set at 900 ° C.

The useful work of the combined cycle gas turbine 9 and the backpressure steam turbine 11 is used to drive the electric generator 10 and generate electricity.

The gas-vapor mixture exiting the gas-vapor turbine 9 through the gas-vapor mixture pipeline 15 is supplied to the recovery boiler 16 of the heat recovery unit 2 of the gas-vapor mixture. The heat of the vapor-gas mixture is disposed of in a waste heat boiler 16 to generate superheated high pressure steam. Feed water is supplied to the economizer 19, the boiler - the utilizer 16. Saturated steam is generated in the evaporation surface 18. After overheating in the superheater 17, superheated high-pressure steam with standard initial parameters is supplied through the steam line 14 to the backpressure steam turbine 11 of the gas-steam turbine unit 1. The gas-vapor mixture after the water economizer 19 is cooled in the gas-water heater 20, heating the mains water of the heating network through the pipeline 31 of the return heating system line and discharged through the pipeline 32 of the direct heating network line.

In the steam-gas mixture cooled in the gas-water heater 20 of the recovery boiler 16, cooling water with a temperature of 20-30 ° C. is injected through the irrigation device 21, supplied from the heat use unit 3 of the separated water through the irrigation water pipe 26. Due to this, in the gas-cooler-condenser 22 condense the vapor component of the vapor-gas mixture. In the separation device of the gas cooler-condenser 23, a mixture of condensate of the vapor-gas mixture and irrigation water from the fuel combustion products is separated. The products of combustion in the exhaust duct 23 with a smoke exhauster are discharged into the atmosphere.

The water separated in the gas cooler-condenser separation device 22 is piped 24 to the separated water tank 25. A smaller portion of the separated water is fed through the feed water pipe 27 after it is softened and deaerated in the installation 28 to the inlet of the water economizer 19 of the recovery boiler 16 of the unit 2 heat recovery gas-vapor mixture.

Most of the separated water is fed to the inlet of the heat pump unit 29, in which it is cooled by heating network water in it. Mains water through a pipeline 30 is supplied to a heat pump installation 29 from a return pipe of a heating network 33 and is withdrawn through a pipeline 31 of network water to a direct heating network 32 of a heat and gas mixture recovery unit 2.

Cooled in the heat pump unit 29, most of the separated water through the irrigation water pipe 26 is supplied to the irrigation device 21 for injection into the gas-vapor mixture exiting the gas-water heater 20 of the recovery boiler 16 of the heat and gas mixture recovery unit 2.

Claims (1)

The method of operation of a gas-steam heat and power plant, according to which atmospheric air is compressed in a compressor and fuel is burned in it in a combustion chamber, useful work of a high-pressure turbine is used to compress air, and a low-pressure turbine is used to drive an electric generator and generate electricity; the heat of the spent steam-gas mixture is utilized for generating superheated steam and heating the mains water, the superheated steam is expanded in a counter-pressure steam turbine, the useful work of which is used to generate electricity, the “ecological” steam expanded in the counter-pressure steam turbine is fed to the combustion products leaving the high-pressure gas turbine , characterized in that the "energy" steam is fed into the combustion zone of the fuel of the same combustion chamber, and the heating of the network water is additionally carried out through heat pump installation.

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