RU2349764C1 - Combined heat and power plant overbuilt with gas turbine plant - Google Patents

Abstract

FIELD: power production.

SUBSTANCE: combined heat and power plant is overbuilt with gas turbine plant. Air cooler - steam generator is available in the air duct behind air compressor. The steam generator includes economising, evaporating and steam superheating surfaces. The first stage of economising surface is linked with deaerator at water inlet. At water outlet, it is linked with gas water heater inlet of feed water. The gas water heater outlet is connected with the evaporating surface of the air cooler - steam generator via pipeline. The air cooler - steam generator outlet is linked with high pressure steam line of the combined heat and power plant through the additional steam heater. The low pressure combustion chamber and the second stage high-pressure steam heater are installed in series between the high and low pressure gas turbines. The gas water heater for delivery water from heat supply system is installed in low pressure gas line behind the gas water heater of feed water.

EFFECT: increase of effective power and cycle economy in combined heat and power plant overbuilt with gas turbine plant.

3 dwg

Description

The invention relates to the field of energy and can be applied to modernize existing heat and power plants.

An urgent task is the modernization of existing cogeneration plants with an increase in their thermal efficiency. The most effective is their modernization by means of superstructure with gas turbine units with steam recovery boilers. At the same time, steam from waste heat boilers is supplied via superheated steam pipelines to the main steam line of the cogeneration plant.

But when using the majority of gas turbines, due to the lowered gas temperatures at their exhaust in the waste heat boilers, the steam parameters that are standard for combined heat and power plants are not generated, therefore, afterburning boilers install fuel afterburners (S. Tsanev, V. Burov, V .Torzhkov. Efficiency of using fuel afterburning in CCGT-KES schemes with single-circuit boilers - utilizers. Gas Turbine Technologies, January-February 2003, p.2-6).

The closest in technical essence to the proposed technical solution is a combined cycle gas turbine unit (E.A. Manushin, V.E. Mikhaltsev, A.P. Chernobrovkin “Theory and design of gas turbine and combined installations.” M.: “Mechanical Engineering ", 1977, fig. 50, p. 127).

A combined cycle gas turbine unit contains a gas turbine unit equipped with an air compressor, high and low pressure gas turbines, a recuperator, high and low pressure combustion chambers, and a gas-water heater. An air compressor and a high pressure gas turbine are connected by a common shaft, a low pressure gas turbine (free turbine) is connected to an electric generator. The high pressure combustion chamber is installed in the duct in front of the high pressure gas turbine, the low pressure combustion chamber is located in the gas pipeline between the high and low pressure gas turbines. The recuperator is installed on the gas side in the gas duct between the exhaust pipe of the low pressure gas turbine and the gas-water heater, and on the air side - in the duct between the air compressor and the high-pressure steam generator of the steam turbine unit. The latter contains a high-pressure steam generator, a steam turbine associated with an electric generator, and a condenser. The condenser is connected by a feed water pipe through a feed pump and a gas-water heater with a high-pressure steam generator. The latter is connected in a sharp pair with a steam turbine. By compressed air, a high-pressure steam generator is included in the air duct between the recuperator and the high-pressure combustion chamber of the gas turbine unit. The use of a high-pressure steam generator in the prototype installation allows to reduce the metal consumption of a combined-cycle plant.

Placing a recuperator in the duct between the air compressor and the high-pressure steam generator increases the thermal efficiency of the combined cycle plant. The installation of a low-pressure combustion chamber in a gas pipeline between gas turbines of high and low pressure helps to increase the capacity of the installation and ensures its high thermal efficiency under variable loads.

But because of the high degrees of compression and the air temperature after the air compressor in gas turbine units with intermediate heat supply, the recuperative air heater used in the prototype is ineffective and does not significantly increase the thermal efficiency of the combined cycle plant. In addition, the placement of a high-pressure steam generator in the duct after the recuperative air heater does not allow steam to be generated in the high-pressure steam generator with standard parameters for existing steam turbine plants, which does not allow the use of a gas-vapor prototype unit for modernization of heat and power plants.

The objective of the proposed technical solution is the modernization of existing combined heat and power plants on a combined cycle cycle with their superstructure by a gas turbine unit, which allows to increase the thermal efficiency and electric power of the combined heat and power plant, and to reduce the metal consumption of a combined cycle plant.

The problem is solved due to the fact that the combined heat and power plant, built on a gas turbine installation, comprising: a gas turbine unit including an air compressor, gas turbines of high and low pressure, a recuperator, combustion chambers of high and low pressure, a gas-water heater, a high-pressure steam generator; the air compressor and the high-pressure gas turbine are connected by a common shaft, the low-pressure gas turbine is connected by a shaft to the electric generator, the high-pressure combustion chamber is installed in the duct in front of the high-pressure gas turbine, the low-pressure combustion chamber is located in the gas pipeline between the high and low pressure gas turbines, the recuperator is installed on the gas side in the duct between the exhaust pipe of the low pressure gas turbine and the gas-water feed water heater, and on the air side - in the duct between the air compressor and the high-pressure combustion chamber; a combined heat and power unit, including a steam boiler, a high pressure steam pipe, a heating steam turbine connected by a common shaft with an electric generator, a high pressure deaerator, a heating system with reverse and direct mains water pipes, heating surfaces of a high pressure steam generator connected to the inlet piping of feed water with a deaerator of the combined heat and power unit, and at the outlet with the high pressure steam line of this unit, while in the duct, between the air compressor and the recuperator In addition, a high-pressure air-cooler-steam generator is placed, including the first stage of the economizer, the second part of the evaporator and the first stage of the superheater heating surfaces; at the water inlet, the first stage of the economizer-like heating surface of the high-pressure air-cooler-steam generator is connected through the feed water pipeline to the deaerator of the heat and power unit, and at the outlet the inlet pipe of the gas-water feed water heater, including the second economizer stage of the feeder fresh water and the first part of the evaporative heating surface; the outlet pipe of the gas-water feed water heater is connected by a pipeline to the second part of the evaporating surface of the high-pressure air cooler-steam generator, the outlet pipe of which is connected by a steam pipe through an additional high-pressure second-stage superheater with a high-pressure steam pipe of the central heating unit; along the combustion products in the gas pipeline between the gas turbines of high and low pressure, a low-pressure combustion chamber and a high-pressure superheater of the second stage are sequentially placed; along the combustion products in the low pressure gas duct after the gas-water feed water heater, a gas-water heater of the heating network water is installed, connected to the return and direct water pipelines of the heat and power plant block.

The use of an additional high-pressure air cooler - a steam generator, including the first economizer, the second part of the evaporative and the first stage of the superheater heating surfaces and its placement in the air duct between the air compressor and the recuperator, as well as the use of an additional high-pressure superheater of the second stage installed in the duct between the high and low pressure gas turbines , and the placement of a low-pressure combustion chamber in front of it, can significantly reduce m the intensity of the gas turbine unit.

The installation of a high-pressure air-cooler-steam generator in the duct between the air compressor and the recuperator allows to lower the air temperature at the inlet to the recuperator and increase the degree of regeneration, thereby increasing the air temperature, reducing fuel consumption in the high-pressure combustion chamber and increasing the thermal efficiency of the combined heat and power plant, built-in gas turbine unit.

Sequential heating of the feed water entering the gas turbine unit from the heat and power plant deaerator, first in the first economizer part of the high-pressure air-cooler-steam generator, and then in the second economizer part in the gas-water feed water heater allows to lower the air temperature in front of the recuperator, increase the degree of regeneration and increase the heat efficiency gas turbine installation.

Placing a low-pressure combustion chamber in a gas pipeline between a high-pressure gas turbine and a second-stage high-pressure superheater allows to increase the temperature head and reduce its metal consumption, as well as to regulate the temperature of the steam supplied to the high-pressure steam pipeline of the combined heat and power plant and to maintain high thermal efficiency of the combined heat and power plant built into the gas turbine unit at its variable loads.

The combination of features is new and allows, due to this combination, to achieve a technical result, which consists in increasing the useful power and increasing the thermal efficiency of the combined heat and power plant built on a gas turbine plant.

The cogeneration plant superstructured by a gas turbine installation is shown in the drawings, in which Fig. 1 shows a schematic diagram of a cogeneration plant superstructured by a gas turbine installation, Fig. 2 shows its block diagram, and Fig. 3 shows a TS diagram of the working process of its gas turbine unit.

In Fig. 1, Fig. 2 shows a gas turbine unit 1, a cogeneration unit 2, an air compressor 3, a high-pressure air cooler-steam generator 4, a second evaporation part and a first stage of a superheater heating surfaces 5, a first economizer stage for heating the feed water 6, a recuperator 7, a chamber high pressure combustion 8, gas pipeline 9, high pressure gas turbine 10, steam pipe 11, second stage high pressure superheater 12, low pressure combustion chamber 13, low pressure gas turbine 14, electric generator 15, high pressure steam pipe 16, cogeneration steam turbine 17, electric generator 18, condenser 19, deaerator 20, feed pump 21, steam boiler 22, feed water pipe 23, return network water pipe 24, direct network water pipe 25, gas-water network heater water 26, gas duct 27, heated feed water pipe 28, gas-water heater 29, steam pipe 30.

The gas turbine unit 1 includes: an air compressor 3, a high-pressure air cooler-steam generator 4, which includes the first economizer stage for heating the feed water 6, the second evaporation part and the first stage of the superheater heating surfaces 5, recuperator 7, high pressure combustion chamber 8, gas pipeline 9, high-pressure gas turbine pressure 10, steam line 11, high-pressure superheater of the second stage 12, low-pressure combustion chamber 13, low-pressure gas turbine 14, electric generator 15, pipeline Flax water 23, return water conduit 24, the conduit line 25 the water mains, gas-delivery water heater 26, flue 27, the preheated feed water conduit 28, gas-heater 29, the steam pipe 30.

The cogeneration unit 2 includes: a high pressure steam line 16, a cogeneration steam turbine 17, an electric generator 18, a condenser 19, a deaerator 20, a feed pump 21, a steam boiler 22.

The combined heat and power plant, built on a gas turbine installation, operates as follows. Atmospheric air compressed in the air compressor 3 of the gas turbine unit 1 enters the high-pressure air cooler-steam generator 4, in which the first stage of the superheater, the second part of the evaporative 5 heating surfaces and the first economizer stage 6 of the feed water are placed along the air.

Cooled in the high-pressure air cooler-steam generator 4, the compressed air is then heated in the heated side of the recuperator 7 by the exhaust gases of the low-pressure gas turbine 14 and is additionally heated in the high-pressure combustion chamber 8 by burning fuel. Then, the resulting combustion products, leaving the gas pipeline 9, expand in a high-pressure gas turbine 10 leading to an air compressor 3, are heated in a low-pressure combustion chamber 13, partially cooled in a high-pressure superheater of the second stage 12. After that, the exhaust gases expand in a low-pressure gas turbine 14, driving the electric generator 18, and are supplied to the heating side of the recuperator 7.

After the recuperator 7, the exhaust gases through the gas duct 27 sequentially pass through the heating sides of the gas-water heater 29, the gas-water heater of network water 26 and are discharged into the atmosphere.

Feed water from the deaerator 20 of the cogeneration unit 2 by the feed pump 21 is fed through the feed water pipe 23 to the first economizer stage 6 of feed water heating of the high-pressure air cooler-steam generator 4 of the gas turbine unit 1. Then, it is fed through the heated feed water pipe 28 to the second economizer feed water heating stage gas-water heater 29 and further enters the first part of the evaporative heating surface of this heater and then through the pipe 30 under leads to the inlet pipe of the second evaporation part and the first superheater stage 5 of the high-pressure air cooler-steam generator 4. From the outlet pipe of the first stage of the superheater 5, partially superheated water vapor enters the heated side of the high-pressure superheater of the second stage 12 and is then fed to the high pressure steam pipe 16 of the block combined heat and power plants 2. After expansion in the cogeneration steam turbine 17, leading the electric generator 18, this steam condenses into condensate SATOR 19. The steam condensate is heated in regenerative heaters and deaerated in the deaerator 20. The main part of the feed water from the deaerator 20 is fed by the feed pump 21 to the boiler unit 22 of the heat and power unit 2, the superheated steam from which is sent to the high pressure steam line 16. A smaller part of the feed water is supplied feed pump 21 through the feed water pipe 23 to the first economizer stage for heating the feed water 6 high-pressure air cooler-steam generator 4 of the gas turbine unit 1 .

In the TS-diagram in figure 3 shows the thermal processes in the gas and steam-water circuits of the gas turbine unit 1. The numbers in this diagram indicate the characteristic points of its working process:

- points 1-2, air compression in the air compressor 3 (figure 2);

- points 2-3, air cooling in the cooled side of the high-pressure air cooler-steam generator 4 (figure 2).

In its heated side:

- feed water heating in the economizer part (EC1) of the first stage of feed water heating 6;

- completion of evaporation of feed water (ISP2) and superheating of steam in the first stage (PP1) of superheating heating surfaces;

- points 3-12, air heating in the recuperator 7 (figure 2);

- points 12-4, the supply of heat of fuel in the combustion chamber of high pressure 8 (figure 2);

- points 4-5, the expansion of the combustion products in a high pressure gas turbine 10 (figure 2);

- points 5-6, the heat supply of fuel in the combustion chamber of high pressure 13 (figure 2);

- points 6-7, cooling of the combustion products in a high-pressure superheater of the second stage 12 (Fig.2), with steam overheating in its heated side (PP2);

- points 7-8, the expansion of the products of combustion in a low-pressure gas turbine 14 (figure 2);

- points 8-9, cooling of the combustion products in the recuperator 7 (Fig.2) with heating in its heated side of the compressed air 3-12;

- points 9-10, the cooling of the combustion products in the gas-water heater 29 (Fig. 2), in its heated side, the feed water is heated (the second heating stage is EC2) and its partial evaporation in the evaporative heating surface (ISP1);

- points 10-11, the cooling of the combustion products in a gas-water heater of network water 26 (figure 2).

The combined heat and power plant, built on a gas turbine installation, is made as follows. Between the air compressor 3 and the recuperator 7, a high-pressure air cooler-steam generator 4 is additionally installed. The outlet air pipe of the recuperator 7 is connected through a gas pipeline 9 and a high-pressure combustion chamber 8 to a high-pressure gas turbine 10, the outlet pipe of which through a low-pressure combustion chamber 13 and an additional high-pressure superheater the second stage 12 is connected to the inlet of the low pressure gas turbine 14.

A high-pressure gas turbine 10 is connected by a common shaft with an air compressor 3, and a low-pressure gas turbine 14 is connected by a shaft with an electric generator 15. In the course of the combustion products, a gas-water feed water heater 29 and a gas-water heating network water heater 26 are located in the gas duct. High-pressure air cooler-steam generator 4 includes the economizer part of the first stage of heating the feed water 6, the second part of the evaporation surface and the first stage of the superheater heating surfaces 5. In gas-water feed water heater 29 installed economizer part of the second stage of feed water heating and the first part of the evaporative heating surface.

The deaerator 20 of the cogeneration unit 2, through the feed pump 21 is connected by the feed water pipes 23 to the steam boiler 22 of the cogeneration unit 2 and to the inlet pipe of the economizer part of the first stage of the feed water heating 6 of the high-pressure air cooler-steam generator 4 of the gas turbine unit 1. Its outlet pipe is connected by a heated feed pipe water 28 with an inlet pipe of the economizer part (second stage of feedwater heating) of a gas-water feedwater heater 29.

The outlet pipe of the first part of the evaporative heating surface of this heater is connected by a pipe 30 to the inlet pipe of the second evaporative heating surface 5 of the high-pressure air cooler-steam generator 4. The output pipe of the first stage of the superheater 5 of the high-pressure air cooler-steam generator 4 is connected by the steam pipe 11 through the heating surface of the second stage of the high-pressure steam heater 12 high pressure 16 block cogeneration plant 2.

Claims (1)

A combined heat and power plant built on a gas turbine installation and containing a gas turbine unit including an air compressor, high and low pressure gas turbines, a recuperator, high and low pressure combustion chambers, a gas-water heater, and a high-pressure steam generator; the air compressor and the high-pressure gas turbine are connected by a common shaft, the low-pressure gas turbine is connected by a shaft to the electric generator, the high-pressure combustion chamber is installed in the duct in front of the high-pressure gas turbine, the low-pressure combustion chamber is located in the gas pipeline between the high and low pressure gas turbines, the recuperator is installed on the gas side in the duct between the exhaust pipe of the low pressure gas turbine and the gas-water feed water heater, and on the air side - in the duct between the air compressor and the high-pressure combustion chamber; a combined heat and power unit, including a steam boiler, a high pressure steam pipe, a heating steam turbine connected by a common shaft with an electric generator, a high pressure deaerator, a heating system with reverse and direct mains water pipes, heating surfaces of a high pressure steam generator connected to the inlet piping of feed water with a deaerator of the combined heat and power unit, and at the outlet with the high pressure steam line of this unit, characterized in that in the duct between the air compressor and The co-cooler additionally contains a high-pressure air-cooler-steam generator, including the first economizer stage, the second evaporative part and the first stage of the superheater heating surfaces, the first stage of the economizer-type heating surface of the high-pressure air-cooler-steam generator is connected through a feed water pipe to the deaerator of the central heating unit at the water inlet the inlet pipe of the gas-water feed water heater, including the second economizer stup the lack of feed water and the first part of the evaporative heating surface; the outlet pipe of the gas-water feed water heater is connected by a pipeline to the second part of the evaporating surface of the high-pressure air cooler-steam generator, the outlet pipe of which is connected by a steam pipe through an additional high-pressure second-stage superheater with a high-pressure steam pipe of the central heating unit; along the combustion products in the gas pipeline between the gas turbines of high and low pressure, a low-pressure combustion chamber and a high-pressure superheater of the second stage are sequentially placed; along the combustion products in the low pressure gas duct after the gas-water feed water heater, a gas-water heater of the heating network water is installed, connected to the return and direct water pipelines of the heat and power plant block.

Images