A solar-gas combined cycle power generation system

Abstract

A solar-gas combined cycle power generation system includes a gas-steam combined cycle subsystem and a solar direct steam subsystem. The gas-steam combined cycle subsystem includes a gas turbine, a waste heat boiler, a steam turbine unit and a feed water pump unit, and the solar direct steam subsystem includes a trough-type solar thermal collector preheating area, a thermal collector evaporation area, a thermal collector superheating area, a circulation pump and a steam-water separator. The exhaust gas of the gas turbine heats the high-pressure part of the feed water of the waste heat boiler to produce high-pressure steam. After preheating, the feed water of the low-pressure part can reach the saturation temperature through the evaporator and the solar collector. The hot water heater at the tail heats the inlet feed water of the solar collector preheating area, so as to reduce the exhaust gas temperature of the waste heat boiler. The present invention not only improves the heat exchange efficiency of the waste heat boiler, but also improves the energy utilization efficiency. According to the changes in the intensity of direct solar radiation, the operation mode can be flexibly changed to achieve stable operation of the unit, realizing multi-energy complementarity and cascade utilization.

Description

Technical Field

[0001] The invention relates to the technical field of power generation equipment, and in particular to a solar energy-gas combined cycle power generation system. Background Art

[0002] Solar energy is an inexhaustible clean energy with a very broad development prospect. Solar thermal power generation has been developed to varying degrees around the world, but due to the discontinuity and instability of solar energy, its large-scale commercial application has been hindered to a certain extent. Gas-steam combined cycle power generation is a clean energy power generation method with low environmental pollution, short construction period and reliable and stable operation. The core equipment of the gas-steam combined cycle is the gas turbine. The gas turbine is very stable during operation, but its performance is greatly affected by environmental factors. In order to improve the thermal efficiency of the gas-steam combined cycle, the exhaust temperature of the waste heat boiler can be reduced as much as possible within a certain range. Both forms of energy utilization have certain shortcomings. The complementary power generation form can effectively reduce the impact of high temperature weather on the unit output, and can also enable the unit to generate electricity continuously and stably.

[0003] The use of a single energy type is subject to many constraints. Therefore, in the future development process, building a comprehensive energy system that organically integrates and complements multiple energy sources is becoming a major trend. Summary of the invention

[0004] The purpose of the present invention is to provide a solar-gas combined cycle power generation system, which is an energy complementary power generation method. The operating performance of the system is improved by replacing the evaporator of the waste heat boiler with a solar collector field and using the boiler tail heater as a solar collector preheating method. This method can effectively improve the heat exchange efficiency of the waste heat boiler and the continuous stability of solar power generation.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A solar-gas combined cycle power generation system comprises a gas-steam combined cycle power generation subsystem and a solar direct steam subsystem, wherein the two subsystems are connected via a pipeline;

[0007] The gas-steam combined cycle power generation subsystem includes a gas turbine, a gas turbine generator, a waste heat boiler, a condenser, a steam turbine, a steam turbine generator, a condensate pump and a high-pressure feed water pump;

[0008] The gas turbine compressor is used to absorb air from the outside atmosphere and compress it. The compressed air is mixed with the fuel injected into the combustion chamber and then burned. The high-temperature and high-pressure flue gas generated enters the gas turbine turbine to work, driving the compressor to rotate and the gas turbine generator to generate electricity. The exhaust gas of the gas turbine enters the waste heat boiler, passes through the high-pressure superheater, high-pressure evaporator, high-pressure economizer, low-pressure superheater, low-pressure evaporator, low-pressure economizer and tail heat exchanger of the waste heat boiler, and is finally discharged to the atmosphere through the chimney; the high-pressure heat exchange steam generated in the high-pressure heat exchange zone directly enters the high-pressure cylinder of the steam turbine to work, and the feed water in the low-pressure heat exchange zone can enter the low-pressure evaporator or the heat collection evaporation zone of the solar direct steam system through the low-pressure steam drum after passing through the low-pressure economizer to generate low-pressure superheated steam; the tail heat exchanger preheats the feed water to 80°C to 90°C and then supplies it to the heat collection preheating zone of the solar direct steam; the high-pressure feed water pump is connected to the low-pressure steam drum, and the high-pressure feed water pump pressurizes the water in the low-pressure steam drum and supplies it to the high-pressure economizer;

[0009] The solar direct steam subsystem includes a heat collection preheating zone, a heat collection evaporation zone, a steam-water separator, a circulation pump and a heat collection superheating zone; the feed water of the heat collection preheating zone comes from the outlet of the hot water heat exchanger of the waste heat boiler, and the feed water enters the heat collection evaporation zone after preheating to reach the saturation temperature, and then is separated by the steam-water separator, and the saturated water returns to the heat collection evaporation zone through the circulation pump to continue heating, and the separated saturated steam passes through the heat collection superheating zone to generate low-pressure superheated steam, and the low-pressure superheated steam generated by the solar direct steam system and the low-pressure superheated steam generated by the waste heat boiler are combined and then enter the low-pressure superheated steam manifold, and then mixed with the high-pressure cylinder exhaust steam and enter the low-pressure cylinder of the turbine to do work; the exhaust steam of the low-pressure cylinder enters the condenser, and the condensed water is supplied to the low-pressure economizer and hot water heat exchanger of the waste heat boiler through the condensate pump, thereby achieving a thermal cycle.

[0010] A further improvement of the present invention is that the waste heat boiler is a dual-pressure natural circulation, and the low-pressure superheated steam generated in the low-pressure heat exchange zone of the waste heat boiler matches the parameters of the superheated steam generated by the solar direct steam system.

[0011] A further improvement of the present invention is that the heat collecting evaporation area of ​​the solar direct steam system is used to replace the low-pressure evaporator of the waste heat boiler.

[0012] A further improvement of the present invention is that a hot water heater is installed at the tail of the waste heat boiler to heat the feed water of the solar heat collection preheating area, so as to improve the heat exchange efficiency of the waste heat boiler and reduce the investment in the solar heat collection preheating area.

[0013] A further improvement of the present invention is that the solar direct steam system adopts a trough collector, and the trough solar collector field is divided into a preheating zone, an evaporation zone and a superheating zone according to different heat collection temperatures.

[0014] A further improvement of the present invention is that after the waste heat boiler low-pressure evaporator is put into use in the solar thermal field, it is completely or partially replaced. At this time, the temperature of the flue gas remains unchanged or is partially reduced when flowing through the low-pressure evaporator, and the water vapor with saturated temperature generated by the low-pressure evaporator and the solar thermal field enters the low-pressure steam drum for steam-water separation.

[0015] A further improvement of the present invention is that the waste heat boiler tail heater heats the condensate to 80°C to 90°C, which is close to the exhaust temperature of the waste heat boiler, and after heating, it is used as feed water for the preheating area of ​​the solar collector field.

[0016] A further improvement of the present invention is that the steam-water mixture in the evaporation zone of the solar collector field passes through a steam-water separator, the separated water enters the superheating zone of the collector field, and the separated water returns to the evaporation zone through a circulation pump.

[0017] A further improvement of the present invention is that the waste heat boiler is of double-pressure, horizontal, natural circulation type.

[0018] The present invention has at least the following beneficial technical effects:

[0019] 1. Solar energy and gas complement each other. Compared with single solar power generation, the power station can operate continuously without increasing energy storage, which effectively improves the stability of the unit. Compared with single gas power generation, the addition of solar power generation improves the power generation capacity of clean energy.

[0020] 2. The two energy sources are coupled through the waste heat boiler, and solar energy collection is used to replace the low-pressure evaporator of the waste heat boiler, which is flexible and reliable in operation.

[0021] 3. Using the tail heater of the waste heat boiler to heat the solar thermal feed water can reduce the exhaust gas temperature of the waste heat boiler and further improve the heat exchange efficiency of the waste heat boiler; on the other hand, it also reduces the investment in the solar thermal preheating area. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the solar energy-gas combined cycle power generation system of the present invention.

[0023] Description of reference numerals:

[0024] 1. Compressor, 2. Combustion chamber, 3. Gas turbine, 4. Gas turbine generator, 5. High-pressure superheater, 6. High-pressure evaporator, 7. High-pressure economizer, 8. High-pressure steam drum, 9. Low-pressure superheater, 10. Low-pressure evaporator, 11. Low-pressure economizer, 12. Low-pressure steam drum, 13. High-pressure feed water pump, 14. Tail heat exchanger, 15. Heat collection preheating area, 16. Heat collection evaporation area, 17. Steam-water separator, 18. Circulating pump, 19. Heat collection superheating area, 20. Condenser, 21. Low-pressure steam main pipe, 22. Turbine high-pressure cylinder, 23. Turbine low-pressure cylinder, 24. Turbine generator, 25. Condensate pump. DETAILED DESCRIPTION

[0025] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0026] Reference Figure 1 The purpose of this invention is to establish a form of energy utilization in which solar energy and gas-steam combined cycle complement each other, aiming to solve the utilization form of single energy, increase the complementary utilization of clean energy, and improve the efficiency and continuity of system operation.

[0027] To achieve the above-mentioned purpose, the present invention provides a solar-gas combined cycle power generation system, comprising a gas turbine generator set consisting of a compressor 1, a combustion chamber 2, a gas turbine 3 and a gas turbine generator 4. The waste heat boiler consists of a high-pressure superheater 5, a high-pressure evaporator 6, a high-pressure economizer 7, a high-pressure drum 8, a high-pressure feedwater pump 13, a low-pressure superheater 9, a low-pressure evaporator 10, a low-pressure economizer 11, a low-pressure drum 12 and a tail heat exchanger 14. The solar direct steam system consists of a heat collection preheating area 15, a heat collection evaporation area 16, a steam-water separator 17, a circulating pump 18 and a heat collection superheating area 19. The equipment of the steam turbine generator set consists of a condenser 20, a low-pressure steam main pipe 21, a steam turbine high-pressure cylinder 22, a steam turbine low-pressure cylinder 23, a steam turbine generator 24 and a condensate pump 25.

[0028] The high-pressure superheated steam of the waste heat boiler is connected to the high-pressure cylinder of the steam turbine through the high-pressure steam pipeline, the low-pressure superheated steam of the waste heat boiler, the solar heat collection superheated steam and the high-pressure cylinder exhaust steam are connected to the low-pressure steam main pipe through the low-pressure steam pipeline, and the low-pressure steam main pipe enters the low-pressure cylinder of the steam turbine through the steam pipeline. The high-pressure cylinder and the low-pressure cylinder of the steam turbine drive the steam turbine generator after working.

[0029] The gas turbine exhaust temperature is above 540°C, the high-pressure superheated steam temperature is 500°C, and the pressure is 5MPa. The low-pressure superheated steam temperature is 200°C, the pressure is 0.5MPa, and the outlet temperature of the tail heat exchanger is 80°C. The outlet pressure of the condensate pump is 1MPa, and the outlet pressure of the high-pressure feed water pump is 5.9MPa.

[0030] The following is a further explanation of the use and method of the system: On rainy days or at night, the solar energy intensity is insufficient, the heat collection temperature cannot meet the design requirements, and the solar heat collection field cannot be put into operation. At this time, the unit should cut off the connection from the feed water to the tail heat exchanger and the solar heat collection superheating area to the low-pressure steam main pipe, and the gas-steam combined cycle unit continues to operate. When the unit is started. First, the gas turbine is started, and the exhaust gas enters the waste heat boiler. After the gas turbine stabilizes at a low load, the waste heat boiler slowly increases the temperature and pressure. After reaching a certain pressure, the gas turbine load is increased, and the parameters of the waste heat boiler are slowly increased to the rated value. Secondly, during the process of heating and pressurizing the waste heat boiler, the high and low pressure superheated steam should go to the condenser through the bypass system. After the temperature and pressure reach the rated value, the bypass is slowly closed, and the main steam enters the steam turbine to do work. Finally, after all parameters reach the rated working value, the gas turbine is loaded, and the steam turbine load is coordinated to increase to the rated value.

[0031] When the gas-steam combined cycle unit is stable and the direct solar radiation intensity reaches the required minimum value, the condensate is gradually opened to the solar field's heat collection preheating area according to the radiation intensity, and the water flow rate of the heat collection field should be adjusted according to the parameter changes of the heat collection superheated steam. The outlet of the waste heat boiler low-pressure economizer to the solar heat collection evaporation area is slowly opened, and the inlet and outlet flow rates are adjusted according to the outlet parameters of the heat collection evaporation area.

[0032] The purpose of the present invention is to propose a method, a specific unit start-up and shutdown and operation strategy, and the relevant knowledge should be well known to professional and technical personnel.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A solar-gas combined cycle power generation system, characterized in that: It includes a gas-steam combined cycle power generation subsystem and a solar direct steam subsystem, and the two subsystems are connected by pipelines; The gas-steam combined cycle power generation subsystem includes a gas turbine, a gas turbine generator, a waste heat boiler, a condenser, a steam turbine, a steam turbine generator, a condensate pump and a high-pressure feed water pump; The compressor is used to absorb air from the outside atmosphere and compress it. The compressed air is mixed with the fuel injected into the combustion chamber and then burned. The high-temperature and high-pressure flue gas generated enters the turbine of the gas engine to work, driving the compressor to rotate and the gas engine generator to generate electricity. The exhaust gas of the gas turbine enters the waste heat boiler, passes through the high-pressure superheater, high-pressure evaporator, high-pressure economizer, low-pressure superheater, low-pressure evaporator, low-pressure economizer and tail heat exchanger of the waste heat boiler in turn, and is finally discharged to the atmosphere through the chimney; the high-pressure heat exchange steam generated in the high-pressure heat exchange zone directly enters the high-pressure cylinder of the steam turbine to work, and the feed water in the low-pressure heat exchange zone passes through the low-pressure drum after passing through the low-pressure economizer, and the other way passes through the heat collection evaporation zone of the solar direct steam system to generate low-pressure superheated steam; the tail heat exchanger preheats the feed water and supplies it to the heat collection preheating zone of the solar direct steam; the high-pressure feed water pump is connected to the low-pressure drum, and the high-pressure feed water pump pressurizes the water in the low-pressure drum and supplies it to the high-pressure economizer; The solar direct steam subsystem includes a heat collection preheating zone, a heat collection evaporation zone, a steam-water separator, a circulation pump and a heat collection superheating zone; the feed water of the heat collection preheating zone comes from the outlet of the tail heat exchanger of the waste heat boiler, and the feed water enters the heat collection evaporation zone after preheating to reach the saturation temperature, and then passes through the steam-water separator for separation, and the saturated water returns to the heat collection evaporation zone through the circulation pump for further heating, and the separated saturated steam passes through the heat collection superheating zone to generate low-pressure superheated steam, and the low-pressure superheated steam generated by the solar direct steam system and the low-pressure superheated steam generated by the waste heat boiler are combined and then enter the low-pressure superheated steam manifold, and then mixed with the high-pressure cylinder exhaust steam and enter the low-pressure cylinder of the steam turbine to perform work, wherein the saturated temperature water vapor generated by the low-pressure evaporator and the solar collector field enters the low-pressure steam drum for steam-water separation; the exhaust steam of the low-pressure cylinder enters the condenser, and the condensed water is supplied to the low-pressure economizer and the tail heat exchanger of the waste heat boiler through the condensate pump, thereby achieving a thermodynamic cycle; The waste heat boiler is a dual-pressure natural cycle, and the low-pressure superheated steam generated in the low-pressure heat exchange zone of the waste heat boiler matches the parameters of the superheated steam generated by the solar direct steam system; The waste heat boiler tail heater heats the condensed water to 80°C to 90°C, which is close to the exhaust temperature of the waste heat boiler. After heating, it is used as feed water for the preheating area of ​​the solar thermal field.

2. A solar-gas combined cycle power generation system according to claim 1, characterized in that: The heat collecting evaporation area of ​​the solar direct steam system is used to replace the low-pressure evaporator of the waste heat boiler.

3. A solar-gas combined cycle power generation system according to claim 1, characterized in that: A tail heat exchanger is installed at the tail of the waste heat boiler to heat the feed water of the solar heat collection preheating area, which is used to improve the heat exchange efficiency of the waste heat boiler and reduce the investment in the solar heat collection preheating area.

4. A solar-gas combined cycle power generation system according to claim 1, characterized in that: The solar direct steam system uses a trough collector. According to the different collection temperatures, the trough solar collector field is divided into a preheating zone, an evaporation zone and a superheating zone.

5. The solar-gas combined cycle power generation system according to claim 1, characterized in that: The steam-water mixture in the evaporation zone of the solar collector field passes through the steam-water separator, the separated steam enters the superheating zone of the collector field, and the separated water returns to the evaporation zone through the circulation pump.

6. A solar-gas combined cycle power generation system according to claim 1, characterized in that: The waste heat boiler is of double-pressure, horizontal, natural circulation type.

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