RSOC coupling coal-fired power generation system participating in primary frequency modulation and operation method

Abstract

The invention discloses an RSOC coupling coal-fired power generation system participating in primary frequency modulation and an operation method. The system comprises a coal-fired power generation unit thermodynamic system and a reversible solid oxide fuel cell RSOC coupling system. When the frequency of the power grid rapidly rises, various valves are reasonably controlled, the power of the steam turbine is rapidly increased, meanwhile, the RSOC is switched into a power generation mode, chemical energy is rapidly converted into electric energy to be merged into the power grid, reaction products are introduced into the small steam turbine to continue acting, and the total power generation power of the whole system is further rapidly increased; when the frequency of the power grid is rapidly reduced, the RSOC is switched into an electric energy storage mode while the power of the steam turbine is rapidly reduced by reasonably controlling various valves, electric energy generated by a coal-fired power generating unit is rapidly consumed through electrolysis, the high-pressure heater water supply flow is increased by utilizing water stored in a water storage tank, and the power of a high-pressure cylinder and a medium-pressure cylinder of the steam turbine is further rapidly reduced; and the total power of the whole system is rapidly reduced. Different power generation units are coupled, the characteristics of high power generation speed and flexible operation of the RSOC are brought into full play, and the primary frequency modulation capability of the coal-fired power generation system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal-fired power generation and frequency modulation, and in particular relates to a RSOC-coupled coal-fired power generation system and an operation method thereof that participates in primary frequency modulation. Background Art

[0002] With the proposal of the "dual carbon" goal, the installed capacity of new energy power generation such as wind power and solar energy has increased significantly. However, due to the fact that they are easily affected by factors such as seasons and the environment, the power generation is obviously intermittent and uncertain, which brings great challenges to the stability of the power grid frequency. my country is rich in coal resources, so thermal power units will still be the main power generation equipment for some time to come. In order to accept more new energy power generation and connect to the grid, thermal power units have to participate more deeply in the primary frequency regulation of the power grid. For thermal power units, there is a serious lag in the steam generation process. In order to meet the primary frequency regulation requirements of the power grid, the units often adopt the "furnace following machine" operation mode. When a primary frequency regulation action is required, the traditional method is to adjust the main steam valve. In order to further improve the frequency response speed, frequency regulation methods such as high-pressure steam extraction throttling, condensate throttling, and high-pressure bypass have emerged. However, due to the heat storage capacity of high and low heaters, deaerators, and condenser water levels, their frequency regulation capabilities are limited.

[0003] Reversible oxide fuel cell (RSOC) is an energy conversion device that takes into account both power generation and electrolysis operation modes, and has the characteristics of fast power generation speed and flexible operation. When the grid frequency drops, RSOC can generate electricity quickly to increase the grid frequency; when the grid frequency rises, RSOC can consume electricity and convert it into hydrogen, while reducing the grid frequency. Therefore, the coupling system of RSOC and coal-fired generator sets can better meet the primary frequency regulation requirements of the grid. Summary of the invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an RSOC-coupled coal-fired power generation system and an operation method participating in primary frequency regulation. The present invention takes into account the traditional method of regulating the main steam flow, couples RSOC, reasonably designs the system configuration, and adjusts the operation mode under different requirements, which can better meet the primary frequency regulation requirements of the power grid.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] RSOC-coupled coal-fired power generation system participating in primary frequency regulation, including thermal system of coal-fired power generation unit and reversible solid oxide fuel cell RSOC-coupled system;

[0007] The thermal system of the coal-fired power generation unit includes: a boiler 1, a steam turbine high-pressure cylinder 2, a steam turbine medium-pressure cylinder 3, a steam turbine low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, a low-pressure heater 8, a deaerator 9, a feedwater pump 10, a high-pressure heater 11, a feedwater heater 12, and a main steam regulating valve 13; the main steam outlet of the boiler 1 is connected to the steam inlet of the steam turbine high-pressure cylinder 2 through a pipeline, and part of the main steam is adjusted to enter the RSOC stack 19 through the main steam control valve 13, the steam extraction outlet of the steam turbine high-pressure cylinder 2 is connected to the steam inlet corresponding to the high-pressure heater 11 through a pipeline, the steam outlet of the steam turbine high-pressure cylinder 2 is connected to the steam inlet of the steam turbine medium-pressure cylinder 3 through the boiler 1, the first-stage steam extraction outlet of the steam turbine medium-pressure 3 is connected to the steam inlet corresponding to the high-pressure heater 11 through a pipeline, and the second-stage steam extraction outlet of the steam turbine medium-pressure cylinder 3 is connected to the deaerator 9 through a pipeline. The steam outlet of the intermediate pressure cylinder 3 of the steam turbine is connected to the steam inlet of the low pressure cylinder 4 of the steam turbine through a pipeline, the steam extraction outlet of the low pressure cylinder 4 of the steam turbine is connected to the low pressure heater 8 through a pipeline, the steam outlet of the low pressure cylinder 4 of the steam turbine is connected to the condenser 6 through a pipeline, the condensate working medium outlet of the condenser 6 is connected to the condensate working medium inlet of the low pressure heater 8 through a condensate pump 7, the condensate working medium outlet of the low pressure heater 8 is connected to the condensate working medium inlet of the deaerator 9 through a pipeline, the feed water working medium outlet of the deaerator 9 is connected to the feed water working medium inlet of the high pressure heater 11 through a feed water pump 10, the tube side outlet of the high pressure heater 11 is connected to the tube side inlet of the feed water heater 12 through a pipeline, the tube side outlet of the feed water heater 12 is connected to the boiler 1 through a pipeline, the high pressure cylinder 2 of the steam turbine, the intermediate pressure cylinder 3 of the steam turbine and the low pressure cylinder 4 of the steam turbine are coaxially connected, and are connected to the power grid through the generator 5;

[0008] The reversible solid oxide fuel cell RSOC coupling system includes an RSOC stack 19, a first three-way mixing valve 14, an air exhaust valve 15, a boiler stable combustion valve 16, a first blower 17, a first regenerator 18, a second three-way mixing valve 20, an electrolysis mode regulating valve 21, a power generation mode regulating valve 29, a second regenerator 22, a condenser 23, a steam-water separator 24, a dryer 25, a hydrogen storage tank 26, a second blower 27, a third regenerator 28, a small steam turbine 30, a water storage tank 31, a fuel cell unit water pump 32, a water storage regulating valve 33, an AC to DC inverter 34, a first switch 35, a DC to AC The electrolytic working medium water comes from the main steam outlet of the boiler 1 and is connected to the main steam regulating valve 13 through a pipeline. The main steam regulating valve 13 is connected to the first three-way mixing valve 14 through a pipeline. After the electrolytic working medium water is mixed with hydrogen in the first three-way mixing valve 14, it is connected to the fuel side inlet of the RSOC stack 19 through a pipeline. The reaction hydrogen passes through the first fan 27, the third regenerator 28 fuel side, and the second regenerator 22 fuel side in the hydrogen storage tank 26 through a pipeline in sequence, and finally merges with the working medium water in the first three-way mixing valve 14. The fuel side outlet of the RSOC stack 19 is connected to the fuel side outlet of the RSOC stack 19 through the second three-way mixing valve 2 0 is divided into two paths, one of which is connected to the working medium inlet of the small steam turbine 30 through a pipeline via the power generation mode regulating valve 29, and the working medium outlet of the small steam turbine 30 is connected to the inlet of the condenser 23 through a pipeline. The small steam turbine 30 is coaxial with the small generator 38, and the small generator 38 is connected to the power grid through a cable. The other path is connected to the inlet of the condenser 23 through a pipeline via the electrolysis mode regulating valve 21, the fuel tail gas side of the second regenerator 22, and the shell side of the feed water heater 12, and the outlet of the condenser 23 is connected to the steam-water separator 24 through a pipeline. The water separated by the steam-water separator 24 enters the water storage tank 31, and the outlet of the water storage tank 31 is connected to the fuel cell unit. The source water pump 32 is connected through a pipeline, and the outlet pipeline of the fuel cell unit water pump 32 is connected to the condensate inlet pipeline of the deaerator 9 in the thermal system of the coal-fired power generation unit through the water storage regulating valve 33. The steam-water separator 24 is connected to the hydrogen storage tank 26 through the dryer 25 through a pipeline, forming a closed fuel pipeline; the outside air passes through the first fan 17 and the first regenerator 18 fuel side to enter the oxygen inlet end of the RSOC stack 19, and the oxygen at the oxygen outlet end of the RSOC stack 19 passes through the first regenerator 18 and the tail gas side of the third regenerator 28 in turn, and finally enters the boiler through the boiler stable combustion valve 16 or is discharged to the outside environment through the air exhaust valve 15;

[0009] The RSOC stack 19 is connected to the AC-to-DC inverter 34 and the DC-to-AC inverter 36 via cables. The AC-to-DC inverter 34 is connected to the grid via a first switch 35 , and the DC-to-AC inverter 36 is connected to the grid via a second switch 37 .

[0010] The operation method of the RSOC coupled coal-fired power generation system participating in primary frequency modulation is as follows:

[0011] (1) When the grid frequency increases rapidly, the reversible solid oxide fuel cell RSOC coupling system needs to be able to quickly increase the power generation to meet the grid primary frequency regulation requirements. At this time, the RSOC stack 19 is in the power generation mode. The second switch 37 is closed, the first switch 35 is disconnected, the main steam regulating valve 13 is adjusted down, more main steam enters the turbine to do work, and the power of the coal-fired unit is quickly increased. The second fan 27 is turned on to draw hydrogen from the hydrogen storage tank 26, and after being preheated by the third reheater 28 and the second reheater 22 in turn, it is mixed with a small amount of main steam at the first three-way mixing valve 14 and then enters the fuel inlet end of the RSOC stack 19. The first fan 17 is turned on to allow air to be preheated on the fuel side of the first reheater 18 and then enter the oxygen inlet end of the RSOC stack 19. Hydrogen and oxygen quickly react chemically to supply the grid. The frequency response speed of the reversible solid oxide fuel cell RSOC coupling system is improved. The oxygen-depleted air at the oxygen outlet of the RSOC stack 19 passes through the first regenerator 18 and the third regenerator 28 to utilize the remaining heat. The air exhaust valve 15 is opened, the boiler stable combustion valve 16 is closed, and the gas is discharged into the external environment. The electrolysis mode regulating valve 21 is closed, and the power generation mode regulating valve 29 is opened to allow the exhaust gas at the fuel outlet of the RSOC stack 19 to pass into the steam inlet of the small steam turbine 30 to do work. The small steam turbine 30 drives the small generator 38 to generate electricity and then is connected to the power grid through a cable, further improving the frequency response speed of the reversible solid oxide fuel cell RSOC coupling system. The exhaust steam discharged from the outlet of the small steam turbine 30 passes through the condenser 23 and the steam-water separator 24 to collect water into the water storage tank 31 for reuse.

[0012] (2) When the grid frequency decreases rapidly, the coupling system needs to be able to quickly reduce the power generation to meet the grid primary frequency regulation requirements. At this time, the RSOC stack 19 is in the electrolysis mode. The first switch 35 is closed and the second switch 37 is opened. The grid power is converted into DC power through the AC to DC inverter 34 and enters the RSOC stack 19 to provide energy for the electrolysis reaction. The main steam regulating valve 13 is adjusted to reduce the amount of steam entering the turbine, quickly reduce the turbine power, and increase the amount of water vapor entering the RSOC stack 19 to provide reactants for the electrolysis reaction. The second fan 27 draws out hydrogen, which is preheated and mixed with the main steam at the first three-way mixing valve 14. Then, it enters the fuel inlet end of the RSOC stack 19. The air passes through the first fan 17 and the first regenerator 18 into the oxygen inlet end of the RSOC stack 19. Water undergoes electrolysis reaction in the ROSC stack 19 to consume the power of the coal-fired unit power generation unit. The oxygen outlet end of the RSOC stack 19 The rich oxygen is preheated through the first reheater 18 and the third reheater 28 for the reaction gas. The air regulating valve 15 and the boiler stable combustion valve 16 are adjusted to make full use of the rich oxygen. The electrolysis mode regulating valve 21 is opened, and the power generation mode regulating valve 29 is closed, so that the gas product at the RSOC fuel outlet end preheats the reaction gas through the second reheater 22. The boiler feed water is heated through the feed water heater 12 to realize the cascade utilization of the electrolysis waste heat. Finally, the reaction product hydrogen and the water that does not participate in the reaction are condensed and separated through the condenser 23 and the steam-water separator 24, and the water is stored in the water storage tank 31. The hydrogen is dried by the dryer 25 and stored in the hydrogen storage tank 26. The water storage regulating valve 33 is opened, and the water in the water storage tank 31 is collected into the condensate pipeline of the deaerator 9 in the thermal system of the coal-fired power generation unit through the fuel cell unit water pump 32, so as to increase the feed water flow of the high-pressure heater 11, thereby increasing the steam extraction amount, and further quickly reducing the turbine power.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The present invention couples a coal-fired power generation system with a reversible solid oxide fuel cell (RSOC), and rationally designs the system configuration. Under different operating modes, the system internal working fluid can be fully utilized, and water can be drawn from the main steam, which not only meets the temperature requirements of the RSOC stack, but also reduces the heat exchange link, and can quickly react in the RSOC stack to meet the frequency modulation requirements, while taking into account the way of adjusting the main steam flow rate, further improving the frequency modulation capability of the entire system.

[0015] 2. The present invention can realize fast switching of operation modes by controlling various valves, without stopping the machine, and is easy to operate and has a fast response speed. Under this coupling system, the main steam valve in the boiler does not need to frequently adjust its valve opening when responding to the primary frequency modulation demand of the power grid, thereby reducing throttling losses.

[0016] 3. The products after the RSOC stack reaction have a lot of waste heat. Through the corresponding heat recovery device, the energy can be used in a cascade manner to improve the energy utilization efficiency of the entire system. In addition, the water generated in the RSOC stack power generation mode can be added to the deaerator condensate to increase the boiler feed water flow when the grid frequency decreases, thereby increasing the high-pressure steam extraction volume and further quickly reducing the power of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of an RSOC-coupled coal-fired power generation system participating in primary frequency regulation. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and implementation modes.

[0019] Reversible oxide fuel cell (RSOC) is an energy conversion device that takes into account both power generation and electrolysis operation modes, and has the characteristics of fast power generation speed and flexible operation. When the grid frequency decreases, the flow rate of main steam entering RSOC is increased, and the power of coal-fired units is quickly reduced. At the same time, the power generated by the coal-fired units can be converted into chemical energy for storage; when the grid frequency rises, the flow rate of main steam entering RSOC is reduced, and the power of coal-fired units is quickly increased. At the same time, the chemical energy in RSOC can be converted into electrical energy. Therefore, the coal-fired power generation system coupled with ROSC can better meet the primary frequency regulation requirements of the grid.

[0020] like Figure 1 As shown, the present invention provides a RSOC coupled coal-fired power generation system participating in primary frequency modulation, including a thermal system of a coal-fired power generation unit and a reversible solid oxide fuel cell RSOC coupled system.

[0021] The thermal system of the coal-fired power generation unit includes: a boiler 1, a steam turbine high-pressure cylinder 2, a steam turbine intermediate-pressure cylinder 3, a steam turbine low-pressure cylinder 4, a generator 5, a condenser 6, a condensate pump 7, a low-pressure heater 8, a deaerator 9, a feedwater pump 10, a high-pressure heater 11, a feedwater heater 12, and a main steam regulating valve 13; the main steam outlet of the boiler 1 is connected to the steam inlet of the steam turbine high-pressure cylinder 2 through a pipeline, and part of the main steam is adjusted to enter the RSOC stack 19 through the main steam control valve 13, the steam extraction outlet of the steam turbine high-pressure cylinder 2 is connected to the corresponding steam inlet of the high-pressure heater 11 through a pipeline, the steam outlet of the steam turbine high-pressure cylinder 2 is connected to the steam inlet of the steam turbine intermediate-pressure cylinder 3 through the boiler 1, the first-stage steam extraction outlet of the steam turbine intermediate-pressure 3 is connected to the corresponding steam inlet of the high-pressure heater 11 through a pipeline, and the second-stage steam extraction outlet of the steam turbine intermediate-pressure cylinder 3 is connected to the deaerator 9 through a pipeline The steam outlet of the intermediate pressure cylinder 3 of the steam turbine is connected to the steam inlet of the low pressure cylinder 4 of the steam turbine through a pipeline, the steam extraction outlet of the low pressure cylinder 4 of the steam turbine is connected to the low pressure heater 8 through a pipeline, the steam outlet of the low pressure cylinder 4 of the steam turbine is connected to the condenser 6 through a pipeline, the condensate working medium outlet of the condenser 6 is connected to the condensate working medium inlet of the low pressure heater 8 through a condensate pump 7, the condensate working medium outlet of the low pressure heater 8 is connected to the condensate working medium inlet of the deaerator 9 through a pipeline, the feed water working medium outlet of the deaerator 9 is connected to the feed water working medium inlet of the high pressure heater 11 through a feed water pump 10, the tube side outlet of the high pressure heater 11 is connected to the tube side inlet of the feed water heater 12 through a pipeline, the tube side outlet of the feed water heater 12 is connected to the boiler 1 through a pipeline, the high pressure cylinder 2 of the steam turbine, the intermediate pressure cylinder 3 of the steam turbine and the low pressure cylinder 4 of the steam turbine are coaxially connected, and connected to the power grid through the generator 5;

[0022] The reversible solid oxide fuel cell RSOC coupling system includes an RSOC stack 19, a first three-way mixing valve 14, an air exhaust valve 15, a boiler combustion stabilization valve 16, a first blower 17, a first regenerator 18, a second three-way mixing valve 20, an electrolysis mode regulating valve 21, a power generation mode regulating valve 29, a second regenerator 22, a condenser 23, a steam-water separator 24, a dryer 25, a hydrogen storage tank 26, a second blower 27, a third regenerator 28, a small steam turbine 30, a water storage tank 31, a fuel cell unit water pump 32, a water storage regulating valve 33, an AC to DC inverter 34, a first switch 35, a DC to AC inverter 36, a second switch 37, and a small generator 38; an electrolysis The working medium water comes from the main steam outlet of the boiler 1 and is connected to the main steam regulating valve 13 through a pipeline. The main steam regulating valve 13 is connected to the first three-way mixing valve 14 through a pipeline. The electrolyzed working medium water is mixed with hydrogen in the first three-way mixing valve 14 and is connected to the fuel side inlet of the RSOC stack 19 through a pipeline. The reaction hydrogen passes through the first fan 27, the third regenerator 28 fuel side, and the second regenerator 22 fuel side in the hydrogen storage tank 26 through a pipeline in sequence, and finally merges with the working medium water in the first three-way mixing valve 14. The fuel side outlet of the RSOC stack 19 is divided into two paths after passing through the second three-way mixing valve 20. One path is connected to the working medium inlet of the small steam turbine 30 through a pipeline via the power generation mode regulating valve 29. The small steam turbine The working medium outlet of the machine 30 is connected to the inlet of the condenser 23 through a pipeline, the small steam turbine 30 is coaxial with the small generator 38, the small generator 38 is connected to the power grid through a cable, and the other way is connected to the inlet of the condenser 23 through a pipeline via the electrolysis mode regulating valve 21, the fuel tail gas side of the second heat exchanger 22, and the shell side of the feed water heater 12. The outlet of the condenser 23 is connected to the steam-water separator 24 through a pipeline, and the water separated by the steam-water separator 24 enters the water storage tank 31. The outlet of the water storage tank 31 is connected to the fuel cell unit water pump 32 through a pipeline. The outlet pipeline of the fuel cell unit water pump 32 is connected to the condensate inlet pipeline of the deaerator 9 in the thermal system of the coal-fired generator set through the water storage regulating valve 33. The separator 24 is connected to the hydrogen storage tank 26 through a pipeline via a dryer 25 to form a closed fuel pipeline; the outside air enters the oxygen inlet end of the RSOC stack 19 through the first fan 17 and the fuel side of the first reheater 18, and the oxygen at the oxygen outlet end of the RSOC stack 19 passes through the first reheater 18 and the exhaust side of the third reheater 28 in turn, and finally enters the boiler through the boiler stable combustion valve 16 or is discharged to the outside environment through the air exhaust valve 15; the RSOC stack 19 is connected to the AC to DC inverter 34 and the DC to AC inverter 36 through cables, the AC to DC inverter 34 is connected to the power grid through the first switch 35, and the DC to AC inverter 36 is connected to the power grid through the second switch 37.

[0023] The operation method of the RSOC coupled coal-fired power generation system participating in primary frequency regulation is as follows:

[0024] When the grid frequency increases rapidly, the reversible solid oxide fuel cell RSOC coupling system needs to be able to quickly increase the power generation to meet the grid primary frequency regulation requirements. At this time, the RSOC stack 19 is in the power generation mode, the second switch 37 is closed, the first switch 35 is disconnected, and the generated electricity is converted into AC power through the DC to AC inverter 36 and then connected to the grid; the main steam regulating valve 13 is adjusted down to allow more main steam to enter the turbine to do work, and the power of the coal-fired unit is quickly increased. The second fan 27 is turned on to draw hydrogen from the hydrogen storage tank 26, and the hydrogen is preheated in turn through the third reheater 28 and the second reheater 22, and then mixed with a small amount of main steam at the first three-way mixing valve 14 to enter the fuel inlet end of the RSOC stack 19. Since the main steam temperature is very high, the reactants can quickly reach a higher temperature during mixing, which improves the RSOC reaction speed and efficiency; the first fan 17 is turned on to allow air to pass through the first reheater 18 to preheat the fuel side After being heated, the hydrogen enters the oxygen inlet of the RSOC stack 19, and the hydrogen and oxygen react rapidly to supply power to the power grid, thereby improving the frequency response speed of the reversible solid oxide fuel cell RSOC coupling system. The oxygen-depleted air at the oxygen outlet of the RSOC stack 19 passes through the first regenerator 18 and the third regenerator 28 to utilize the remaining heat; the air exhaust valve 15 is opened, and the boiler stable combustion valve 16 is closed to discharge the gas into the external environment; the electrolysis mode regulating valve 21 is closed, and the power generation mode regulating valve 29 is opened to allow the exhaust gas at the fuel outlet of the RSOC stack 19 to pass into the steam inlet of the small steam turbine 30 to perform work, and the small steam turbine 30 drives the small generator 38 to generate electricity and the generated electricity is connected to the power grid through the cable, further improving the frequency response speed of the reversible solid oxide fuel cell RSOC coupling system, and the exhaust steam discharged from the outlet of the small steam turbine 30 passes through the condenser 23 and the steam-water separator 24 to collect water into the water storage tank 31 for reuse.

[0025] When the grid frequency drops rapidly, the reversible solid oxide fuel cell RSOC coupling system needs to be able to quickly reduce the power generation to meet the grid primary frequency regulation requirements. At this time, the RSOC stack 19 is in the electrolysis mode, the first switch 35 is closed, and the second switch 37 is opened. The grid power is converted into DC power through the AC to DC inverter 34 and enters the RSOC stack 19 to provide energy for the electrolysis reaction, quickly consuming the power of the coal-fired generator unit; the main steam regulating valve 13 is adjusted to reduce the amount of steam entering the turbine, quickly reduce the turbine power, and increase the amount of steam entering the RSOC stack. The amount of water vapor in 19 provides reactants for the electrolysis reaction; the hydrogen is drawn out by the second fan 27, and after being preheated, it is mixed with the main steam in the first three-way mixing valve 14 and then enters the fuel inlet end of the RSOC stack 19. Since the temperature of the main steam is high, the temperature of the reactants can reach a higher temperature after mixing, providing favorable conditions for the RSOC reaction; the outside air passes through the first fan 17 and the first regenerator 18 into the oxygen inlet end of the RSOC stack 19. The water undergoes an electrolysis reaction in the RSOC stack 19, consuming the electric energy of the thermal system of the coal-fired power generation unit. The oxygen in the RSOC stack 19 The oxygen-enriched air at the outlet is preheated through the first reheater 18 and the third reheater 28 to preheat the reaction gas. Finally, the oxygen-enriched air after heat exchange can be controlled by the boiler stable combustion valve 16 to enter the furnace to achieve stable combustion under low boiler load. In order to avoid safety problems caused by excessive combustion intensity in the furnace, it can also be discharged into the atmosphere through the air exhaust valve 15; open the electrolysis mode regulating valve 21, close the power generation mode regulating valve 29, so that the gas product at the fuel outlet of the RSOC stack 19 preheats the reaction gas through the second reheater 22, and heats the boiler feed water through the feed water heater 12 to achieve the electrolysis residue The heat is utilized in stages. Finally, the reaction product hydrogen and the water that has not participated in the reaction are condensed and separated by the condenser 23 and the steam-water separator 24 respectively, and the water is stored in the water storage tank 31. The hydrogen is dried by the dryer 25 and stored in the hydrogen storage tank 26. The water storage regulating valve 33 is opened, and the water in the water storage tank 31 is introduced into the condensate pipeline of the deaerator 9 in the thermal system of the coal-fired generator set through the fuel cell unit water pump 32, thereby increasing the water flow rate of the high-pressure heater 11, thereby increasing the steam extraction volume, reducing the main steam flow rate of the high- and medium-pressure cylinders of the turbine, and further quickly reducing the turbine power.

[0026] When the grid frequency rises rapidly, the present invention reasonably controls various valves to rapidly increase the steam turbine power while switching RSOC to power generation mode, rapidly converts chemical energy into electrical energy and incorporates it into the grid, and passes the reaction product into a small steam turbine to continue to work, further rapidly increasing the total power generation of the entire system; when the grid frequency drops rapidly, the present invention reasonably controls various valves to rapidly reduce the steam turbine power while switching RSOC to power storage mode, rapidly consumes the electrical energy generated by the coal-fired generator set through electrolysis, and uses the water stored in the water storage tank to increase the high-pressure feed water flow, further rapidly reducing the power of the high-pressure cylinders of the steam turbine, and achieving the purpose of rapidly reducing the total power of the entire system. The present invention couples different power generation units, gives full play to the characteristics of RSOC's fast power generation speed and flexible operation, and improves the primary frequency regulation capability of the coal-fired power generation system.

Claims

1. RSOC coupled coal-fired power generation system participating in primary frequency regulation, characterized by: It includes the thermal system of coal-fired power generation units and the reversible solid oxide fuel cell RSOC coupling system; The thermal system of the coal-fired power generation unit comprises: a boiler (1), a high-pressure cylinder of a steam turbine (2), an intermediate-pressure cylinder of a steam turbine (3), a low-pressure cylinder of a steam turbine (4), a generator (5), a condenser (6), a condensate pump (7), a low-pressure heater (8), a deaerator (9), a feedwater pump (10), a high-pressure heater (11), a feedwater heater (12), and a main steam regulating valve (13); the main steam outlet of the boiler (1) is connected to the steam inlet of the high-pressure cylinder of the steam turbine through a pipeline, and part of the main steam is regulated to enter the RSOC stack (19) through the main steam control valve (13); the steam extraction outlet of the high-pressure cylinder of the steam turbine (2) is connected to the steam inlet corresponding to the high-pressure heater (11) through a pipeline; the steam outlet of the high-pressure cylinder of the steam turbine (2) is connected to the steam inlet of the intermediate-pressure cylinder of the steam turbine (3) through the boiler (1); the first-stage steam extraction outlet of the intermediate-pressure cylinder of the steam turbine (3) is connected to the steam inlet corresponding to the high-pressure heater (11) through a pipeline; the second-stage steam extraction outlet of the intermediate-pressure cylinder of the steam turbine (3) is connected to the deaerator (9) through a pipeline. The steam outlet of the intermediate pressure cylinder (3) of the steam turbine is connected to the steam inlet of the low pressure cylinder (4) of the steam turbine through a pipeline, the steam extraction outlet of the low pressure cylinder (4) of the steam turbine is connected to the low pressure heater (8) through a pipeline, the steam outlet of the low pressure cylinder (4) of the steam turbine is connected to the condenser (6) through a pipeline, the condensate working medium outlet of the condenser (6) is connected to the condensate working medium inlet of the low pressure heater (8) through a condensate pump (7), and the condensate working medium outlet of the low pressure heater (8) is connected to the deaerator ( 9), the feed water working medium outlet of the deaerator (9) is connected to the feed water working medium inlet of the high-pressure heater (11) through the feed water pump (10), the tube side outlet of the high-pressure heater (11) is connected to the tube side inlet of the feed water heater (12) through a pipeline, the tube side outlet of the feed water heater (12) is connected to the boiler (1) through a pipeline, the turbine high-pressure cylinder (2), the turbine intermediate-pressure cylinder (3) and the turbine low-pressure cylinder (4) are coaxially connected and connected to the power grid through the generator (5); The reversible solid oxide fuel cell RSOC coupling system comprises an RSOC stack (19), a first three-way mixing valve (14), an air exhaust valve (15), a boiler combustion stabilization valve (16), a first blower (17), a first regenerator (18), a second three-way mixing valve (20), an electrolysis mode regulating valve (21), a power generation mode regulating valve (29), a second regenerator (22), a condenser (23), a steam-water separator (24), a dryer (25), a hydrogen storage tank (26), a second blower (27), a third regenerator (28), a small steam turbine (30), a water storage tank (31), and a fuel cell unit water pump (32). 2), a water storage regulating valve (33), an AC to DC inverter (34), a first switch (35), a DC to AC inverter (36), a second switch (37), and a small generator (38); the electrolytic working medium water comes from the main steam outlet of the boiler (1) and is connected to the main steam regulating valve (13) through a pipeline, the main steam regulating valve (13) is connected to the first three-way mixing valve (14) through a pipeline, the electrolytic working medium water is mixed with hydrogen in the first three-way mixing valve (14) and is connected to the fuel side inlet of the RSOC stack (19) through a pipeline, and the reaction hydrogen passes through the first fan (27), the third regenerator ( 28) fuel side, the second regenerator (22) fuel side, and finally merge with the working medium water at the first three-way mixing valve (14). The fuel side outlet of the RSOC stack (19) is divided into two paths after passing through the second three-way mixing valve (20). One path is connected to the working medium inlet of the small steam turbine (30) through a pipeline via the power generation mode regulating valve (29). The working medium outlet of the small steam turbine (30) is connected to the inlet of the condenser (23) through a pipeline. The small steam turbine (30) is coaxial with the small generator (38). The small generator (38) is connected to the power grid through a cable. The other path is connected to the electrolysis mode regulating valve (21) and the second regenerator (22) fuel tail. The gas side and the shell side of the feed water heater (12) are connected to the inlet of the condenser (23) through a pipeline, the outlet of the condenser (23) is connected to the steam-water separator (24) through a pipeline, the water separated by the steam-water separator (24) enters the water storage tank (31), the outlet of the water storage tank (31) is connected to the fuel cell unit water pump (32) through a pipeline, the outlet pipeline of the fuel cell unit water pump (32) is connected to the condensate inlet pipeline of the deaerator (9) in the thermal system of the coal-fired generator set through a water storage regulating valve (33), and the hydrogen after the water is removed from the steam-water separator (24) is connected to the hydrogen storage tank (26) through a pipeline via a dryer (25), thereby forming a closed fuel pipeline; The outside air passes through the first fan (17) and the fuel side of the first regenerator (18) and enters the oxygen inlet end of the RSOC stack (19). The oxygen at the oxygen outlet end of the RSOC stack (19) passes through the first regenerator (18) and the tail gas side of the third regenerator (28) in sequence, and finally enters the boiler through the boiler combustion stabilization valve (16) or is discharged to the outside environment through the air exhaust valve (15); The RSOC stack (19) is connected to the AC-to-DC inverter (34) and the DC-to-AC inverter (36) via cables; the AC-to-DC inverter (34) is connected to the power grid via a first switch (35); and the DC-to-AC inverter (36) is connected to the power grid via a second switch (37).

2. The method for operating the RSOC coupled coal-fired power generation system participating in primary frequency modulation according to claim 1, characterized in that: The details are as follows: (1) When the grid frequency increases rapidly, the reversible solid oxide fuel cell RSOC coupling system needs to be able to quickly increase the power generation to meet the grid primary frequency regulation requirements. At this time, the RSOC stack (19) is in the power generation mode, the second switch (37) is closed, the first switch (35) is opened, the main steam regulating valve (13) is adjusted down, more main steam enters the turbine to perform work, and the power of the coal-fired unit is quickly increased. The second fan (27) is turned on, hydrogen is drawn from the hydrogen storage tank (26), and is preheated in the third reheater (28) and the second reheater (22) in turn. After being mixed with a small amount of main steam at the first three-way mixing valve (14), it enters the fuel inlet end of the RSOC stack (19). The first fan (17) is turned on to allow air to pass through the first reheater (18) to be preheated on the fuel side and then enter the oxygen inlet end of the RSOC stack (19). The hydrogen and oxygen quickly undergo a chemical reaction to supply power to the grid. The frequency response speed of the reversible solid oxide fuel cell (RSOC) coupling system is improved. The oxygen-depleted air at the oxygen outlet of the RSOC stack (19) is passed through a first regenerator (18) and a third regenerator (28) to realize the utilization of the remaining heat. The air exhaust valve (15) is opened, the boiler combustion stabilization valve (16) is closed, and the gas is discharged into the external environment. The electrolysis mode regulating valve (21) is closed, and the power generation mode regulating valve (29) is opened, so that the exhaust gas at the fuel outlet of the RSOC stack (19) is passed into the steam inlet of the small steam turbine (30) to perform work. The small steam turbine (30) drives the small generator (38) to generate electricity and then is connected to the power grid through a cable, so as to further improve the frequency response speed of the reversible solid oxide fuel cell (RSOC) coupling system. The exhaust steam discharged from the outlet of the small steam turbine (30) is passed through a condenser (23) and a steam-water separator (24) to collect water into a water storage tank (31) for reuse. (2) When the grid frequency decreases rapidly, the reversible solid oxide fuel cell RSOC coupling system needs to be able to quickly reduce the power generation to meet the grid primary frequency regulation requirements. At this time, the RSOC stack (19) is in the electrolysis mode, the first switch (35) is closed, and the second switch (37) is opened. The grid power is converted into direct current through the AC to DC inverter (34) and enters the RSOC stack (19) to provide energy for the electrolysis reaction. The main steam regulating valve (13) is adjusted to reduce the amount of steam entering the turbine, and the turbine power is quickly reduced. The amount of water vapor entering the RSOC stack (19) is increased to provide reactants for the electrolysis reaction; the hydrogen is drawn out by the second fan (27), preheated, mixed with the main steam in the first three-way mixing valve (14), and then enters the fuel inlet end of the RSOC stack (19); the air passes through the first fan (17) and the first regenerator (18) into the oxygen inlet end of the RSOC stack (19); the water undergoes an electrolysis reaction in the RSOC stack (19) to consume the electric energy of the coal-fired unit power generation unit; the RSOC stack (19) outputs oxygen. The oxygen-enriched gas at the outlet is preheated by the first regenerator (18) and the third regenerator (28). The oxygen-enriched gas is fully utilized by adjusting the air regulating valve (15) and the boiler combustion stabilization valve (16). The electrolysis mode regulating valve (21) is opened and the power generation mode regulating valve (29) is closed, so that the gas product at the fuel outlet of the RSOC stack (19) preheats the reaction gas through the second regenerator (22). The boiler feed water is heated by the feed water heater (12) to realize the cascade utilization of the electrolysis waste heat. Finally, the condenser (2 3) The steam-water separator (24) condenses and separates the reaction product hydrogen and the water that has not participated in the reaction, respectively, and stores the water in the water storage tank (31). The hydrogen is dried by the dryer (25) and then stored in the hydrogen storage tank (26). The water storage regulating valve (33) is opened, and the water in the water storage tank (31) is introduced into the condensate pipeline of the deaerator (9) in the thermal system of the coal-fired power generation unit through the fuel cell unit water pump (32), thereby increasing the water flow rate of the high-pressure heater (11), thereby increasing the steam extraction amount, and further quickly reducing the power of the steam turbine.

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