A coal-fired power generation system coupled with methanol-based hydrogen production and its operation method

Abstract

The present invention discloses a coal-fired power generation system coupled with methanol hydrogen production and its operating method. The system integrates a steam turbine steam cycle power generation system, a methanol hydrogen production system, and an internal combustion engine power generation system. By diverting a portion of the superheated steam at the boiler superheater and reheater outlets into the methanol reforming hydrogen production system, the air intake flow of the high-pressure cylinder and the intermediate-pressure cylinder is reduced, and the unit operating load is reduced, so that the minimum operating load of the unit is reduced by 10%-15% on the original basis. The internal combustion engine in the introduced internal combustion engine power generation system has a compact structure, easy operation, and fast startup, meeting the requirements of rapid load increase of the unit; the internal combustion engine fuel comes from the hydrogen produced during the deep adjustment period of the unit, and the fuel cost is low; the internal combustion engine exhaust is used to heat condensate and feed water, realizing energy cascade utilization.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible power generation of thermal power units, and relates to a coal-fired power generation system coupled with methanol to hydrogen production and an operation method thereof. Background Art

[0002] In the future, a new power system dominated by renewable energy will be built, characterized by clean, low-carbon, safe, and efficient energy. Due to the highly random and intermittent nature of wind and photovoltaic power generation, their large-scale integration into the grid has negatively impacted the safe and stable operation of the power grid. To improve the absorption capacity of renewable energy, thermal power plants, which account for over 70% of China's electricity generation, must assume peak-shaving duties, and deep peak-shaving will become a regular practice. As the grid's demand for peak-shaving capabilities from traditional thermal power plants continues to increase, the peak-shaving range of these plants urgently needs to expand beyond the traditional load range.

[0003] However, unit cycle efficiency drops significantly at low loads, and further increases in ramp rate are constrained by pulverizing and metal wall temperatures. Further flexibility enhancements are unlikely through modifications to coal-fired power units alone. To further enhance the peak-shaving capacity of thermal power units, improve system operational safety, broaden the peak-shaving range, and enhance operational flexibility, energy storage can be used to improve peak-shaving capacity and smooth the output curve. However, converting steam into electricity for storage results in significant energy waste, while technologies like batteries and compressed air storage are relatively immature and have drawbacks such as high investment and poor safety. In recent years, the use of condensate storage and heat grid energy storage in heating units to significantly enhance the rapid load-scaling capabilities of units has become a new hot topic. This regulation method is directly limited by the deaerator tank water level and the condensate valve opening, resulting in limited load ramping capabilities. Heat grid energy storage systems can utilize grid energy for short periods of time without significantly impacting heat users. However, grid energy storage is limited, and ultimately fuel is required to meet load demand. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a coal-fired power generation system coupled with methanol to hydrogen production and its operation method, so as to break through the traditional load range of thermal power units, improve the peak-shaving capability and rapid load change capability of the units, and further enhance the flexibility of the units.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A coal-fired power generation system coupled with methanol to hydrogen production includes a boiler, wherein the superheated steam of the boiler is divided into two branches, one branch connected to the steam input of a reactor, and the other branch connected to a high-pressure cylinder; the steam output of the high-pressure cylinder is connected to the reheat steam input of the boiler, and the reheat steam output is divided into two branches, one branch connected to the hot side input of a preheater, and the other branch connected to the steam input of an intermediate-pressure cylinder; the exhaust steam output of the intermediate-pressure cylinder is connected to the steam input of a low-pressure cylinder, and the hot side output of the preheater is connected to the steam input of the low-pressure cylinder;

[0007] The steam output end of the low-pressure cylinder is connected to the condenser, the output end of the condenser is connected to the cold side input end of the low-pressure heat exchanger, the cold side output end of the low-pressure heat exchanger is connected to the cold side input end of the high-pressure heat exchanger, and the cold side output end of the high-pressure heat exchanger is connected to the superheated steam pipeline of the boiler;

[0008] The gas output end of the reactor is connected to a hydrogen storage tank, the output end of the hydrogen storage tank is connected to an internal combustion engine, the output end of the internal combustion engine is connected to the hot side input end of the high-pressure heat exchanger, and the hot side output end of the high-pressure heat exchanger is connected to the hot side input end of the low-pressure heat exchanger.

[0009] A further improvement of the present invention is:

[0010] Preferably, the output end of the condenser is connected to a condensate pump, and the outlet of the condensate pump is divided into two branches, one branch is connected to the low-pressure heater, and the other branch is connected to the cold side input end of the low-pressure heat exchanger; a third valve is provided on the connecting pipeline between the condensate pump and the low-pressure heat exchanger.

[0011] Preferably, the outlet of the low-pressure heater and the cold side outlet of the low-pressure heat exchanger are merged and connected to the deaerator together, and the inlet of the deaerator is also connected to the steam extraction outlet of the medium-pressure cylinder; the outlet of the deaerator is respectively connected to the cold side input port of the high-pressure heater and the cold side input port of the high-pressure heat exchanger.

[0012] Preferably, the outlet of the deaerator is connected to the high-pressure heater and the high-pressure heat exchanger respectively through a water feed pump, and a second valve is provided on the connecting pipeline between the water feed pump and the high-pressure heat exchanger.

[0013] Preferably, the cold side outlet of the high-pressure heater and the cold side outlet of the high-pressure heat exchanger are merged and connected to the superheated steam pipeline inlet of the boiler.

[0014] Preferably, the hydrogen and carbon dioxide outlets of the reactor are connected to a separator, and the liquid outlet of the separator is connected to the inlet of the mixer.

[0015] Preferably, the inlet of the mixer is also connected to the outlet of the raw material tank, and a booster pump is provided between the mixer and the raw material tank; the outlet of the mixer is connected to the cold side inlet of the preheater, and the cold side outlet of the preheater is connected to the inlet of the reactor.

[0016] Preferably, the gas outlet of the separator is connected to a pressure swing adsorption device, and the outlet of the pressure swing adsorption device is connected to the inlet of the hydrogen storage tank.

[0017] Preferably, a first valve is provided on the connecting pipeline between the hydrogen storage tank and the internal combustion engine; a first throttle valve is provided on the connecting pipeline between the superheated steam of the boiler and the reactor, and a second throttle valve is provided on the connecting pipeline between the reheated steam of the boiler and the preheater.

[0018] An operating method of the above-mentioned coal-fired power generation system coupled with methanol to hydrogen production, wherein a hydrogen storage tank outputs hydrogen to an internal combustion engine, and high-temperature exhaust gas output by the internal combustion engine passes through a high-pressure heat exchanger and a low-pressure heat exchanger in sequence, and is discharged into the atmosphere after being cooled;

[0019] The condensed water output from the condenser exchanges heat with the exhaust gas of the internal combustion engine in the low-pressure heat exchanger, and then enters the high-pressure heat exchanger to exchange heat with the exhaust gas of the internal combustion engine. The water vapor after heat exchange enters the superheater of the boiler.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention discloses a coal-fired power generation system coupled with methanol hydrogen production. The system integrates a steam turbine steam cycle power generation system, a methanol hydrogen production system, and an internal combustion engine power generation system. By diverting a portion of the superheated steam at the outlet of the boiler superheater and reheater into the methanol reforming hydrogen production system, the air intake flow of the high-pressure cylinder and the medium-pressure cylinder is reduced, and the operating load of the unit is reduced, so that the minimum operating load of the unit is reduced by 10%-15% on the original basis. The internal combustion engine in the introduced internal combustion engine power generation system has a compact structure, easy operation, and fast startup, meeting the requirements of rapid load increase of the unit. The fuel of the internal combustion engine comes from the hydrogen produced during the deep adjustment period of the unit, and the fuel cost is low; the exhaust gas of the internal combustion engine is used to heat condensate and feed water, realizing energy cascade utilization.

[0022] Furthermore, the steam turbine in the present system utilizes a combined high- and medium-pressure cylinder design. Superheated steam from the boiler's superheater and reheater outlets flows into the methanol reforming hydrogen production system at equal mass flow rates, balancing the turbine's axial thrust. The superheated steam diverted into the methanol reforming hydrogen production system ultimately merges with high-pressure exhaust steam and enters the boiler reheater, preventing overheating in the boiler reheater.

[0023] Furthermore, the thermal energy of superheated steam is converted into chemical energy of hydrogen for storage, thus improving the energy quality.

[0024] Furthermore, the steam flow entering the high-pressure cylinder and the intermediate-pressure cylinder through the bypass portion can reduce the unit output, and the steam flow entering the boiler remains basically unchanged, which is conducive to maintaining stable combustion in the boiler.

[0025] The present invention also discloses an operating method for a coal-fired power generation system coupled with methanol to hydrogen production. During a rapid load increase period, the method utilizes the exhaust gas of an internal combustion engine to heat part of the condensate and part of the feed water, reduces the steam extraction amount of the low-pressure heater and the high-pressure heater, and instantaneously increases the amount of steam entering the low-pressure cylinder and the high-pressure cylinder to perform work, thereby achieving the purpose of rapid load increase. Compared with traditional condensate regulation methods, the present invention is not limited by the water level of the deaerator tank and the opening of the condensate valve, can operate for a long time, and has a faster load increase rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural diagram of a coal-fired power generation system coupled with methanol to hydrogen production.

[0027] In the figure: 1 boiler; 2 high-pressure cylinder; 3 medium-pressure cylinder; 4 low-pressure cylinder; 5 first generator; 6 condenser; 7 condensate pump; 8 low-pressure heater; 9 deaerator; 10 feed water pump; 11 high-pressure heater; 12 first throttle valve; 13 second throttle valve; 14 raw material tank; 15 booster pump; 16 mixer; 17 preheater; 18 reactor; 19 separator; 20 pressure swing adsorption device; 21 hydrogen storage tank; 22 first valve; 23 internal combustion engine; 24 high-pressure heat exchanger; 25 low-pressure heat exchanger; 26 second generator; 27 second valve; 28 third valve. DETAILED DESCRIPTION

[0028] The present invention is described in further detail below with reference to the accompanying drawings:

[0029] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise expressly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] The invention discloses a structure of a coal-fired power generation system coupled with methanol-hydrogen production, comprising a steam turbine steam cycle power generation system, a methanol-hydrogen production system and an internal combustion engine power generation system.

[0031] The steam cycle system includes a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a first generator 5, a condenser 6, a condensate pump 7, a low-pressure heater 8, a deaerator 9, a feedwater pump 10 and a high-pressure heater 11.

[0032] The methanol hydrogen production system includes a raw material tank 14 , a booster pump 15 , a mixer 16 , a preheater 17 , a reactor 18 , a separator 19 , a pressure swing adsorption device 20 and a hydrogen storage tank 21 .

[0033] The internal combustion engine power generation system includes an internal combustion engine 23 , a high-pressure heat exchanger 24 , a low-pressure heat exchanger 25 and a second generator 26 .

[0034] The superheated steam outlet of boiler 1 is divided into two branches: the first branch and the second branch. The first branch is connected to the steam inlet of high-pressure cylinder 2, which is connected to the reheat steam pipeline inlet of boiler 1. The second branch is connected to the steam inlet of reactor 18. The reheated steam outlet is divided into two branches: the third branch and the fourth branch. The third branch is connected to intermediate-pressure cylinder 3, the exhaust outlet of intermediate-pressure cylinder 3 is connected to the steam inlet of low-pressure cylinder 4, and the extraction outlet of intermediate-pressure cylinder 3 is connected to the steam-side inlet of deaerator 9. The fourth branch is connected to the hot-side inlet of preheater 17. The power output ends of high-pressure cylinder 2, intermediate-pressure cylinder 3, and low-pressure cylinder 4 are connected to the first generator 5.

[0035] The exhaust steam outlet of the low-pressure cylinder 4 is divided into a fifth branch and a sixth branch. The fifth branch is connected to the inlet of the condenser 6. The outlet of the condenser 6 is connected to the condensate pump 7. The outlet of the condensate pump 7 is divided into two branches, which are respectively connected to the cold side inlet of the low-pressure heater 8 and the cold side inlet of the low-pressure heat exchanger 25. The cold side outlet of the low-pressure heater 8 and the cold side outlet of the low-pressure heat exchanger 25 merge and flow into the deaerator 9.

[0036] The deaerator 9 is provided with two inlets, one connected to the extraction steam outlet of the intermediate pressure cylinder 3, and the other connected to the converging pipeline of the cold side outlet of the low pressure heater 8 and the cold side outlet of the low pressure heat exchanger 25. The outlet of the deaerator 9 is divided into two routes, one connected to the cold side inlet of the high pressure heater 11, and the other connected to the cold side inlet of the high pressure heat exchanger 24; the hot side inlet of the high pressure heater 11 is connected to the exhaust steam of the high pressure cylinder 2, and the cold side outlet pipeline of the high pressure heater 11 and the cold side outlet pipeline of the high pressure heat exchanger 24 are merged and then merged into the superheater inlet of the boiler 1.

[0037] The superheated steam inlet of reactor 18 is connected to the superheater outlet pipeline of boiler 1. The gas outlet of reactor 18 is connected to separator 19. The hydrogen and carbon dioxide outlets of separator 19 enter pressure swing adsorption unit 20. The hydrogen from pressure swing adsorption unit 20 is input into hydrogen storage tank 21. The outlet of hydrogen storage tank 21 is connected to internal combustion engine 23. One inlet of internal combustion engine 23 is connected to the outlet of hydrogen storage tank 21, and another inlet is connected to an air pipeline. The power output end of internal combustion engine 23 is connected to second generator 26 for driving second generator 26. The high-pressure steam outlet of internal combustion engine 23 is connected to the hot side inlet of high-pressure heat exchanger 24, which is connected to the hot side inlet of low-pressure heat exchanger 25. The gas discharged from low-pressure heat exchanger 25 is cooled and discharged into the atmosphere. The steam outlet of reactor 18 is connected to the reheat steam pipeline of boiler 1.

[0038] Methanol is stored in the raw material tank 14, the outlet of the raw material tank 14 is connected to the booster pump 15, the outlet of the booster pump 15 is connected to the mixer 16, the mixer 16 has two inlets, one is connected to the outlet of the separator 19, and one is connected to the outlet of the booster pump 15, the outlet of the mixer 16 is connected to the cold side inlet of the preheater 17, the cold side outlet of the preheater 17 is connected to the inlet of the reactor 18, the hot side inlet of the preheater 17 is connected to the fourth branch of the reheat steam outlet pipeline of the boiler 1, and the hot side outlet of the preheater 17 is connected to the steam inlet of the low-pressure cylinder 4.

[0039] A first throttle valve 12 is provided on the second branch, a second throttle valve 13 is provided on the fourth branch, and a second valve 13 is provided on the connecting pipe between the feedwater pump 10 and the inlet of the high-pressure heat exchanger 24. This valve controls the flow of steam from the deaerator 9 into the high-pressure heater 24. A third valve 28 is provided on the connecting pipe between the outlet of the condensate pump 7 and the low-pressure heat exchanger 2. A first valve 22 is provided on the connecting pipe between the outlet of the hydrogen storage tank 21 and the internal combustion engine 23.

[0040] The working process of the device of the present invention is:

[0041] Deep adjustment process: The superheated steam at the outlet of boiler 1 in the steam turbine steam cycle power generation system is divided into two streams. One stream directly enters the high-pressure cylinder 2 to expand and perform work, driving the first generator 5 to generate electricity. The exhaust steam of the 2 high-pressure cylinders enters the reheater of boiler 1 for heating, and then enters the medium-pressure cylinder 3 and the low-pressure cylinder 4 in turn to expand and perform work, driving the first generator 5 to generate electricity; the other superheated steam enters the methanol reforming hydrogen production system through the first throttle valve 12, releases heat on the hot side of the reactor 18 in the methanol reforming hydrogen production system, and then merges with the exhaust steam of the high-pressure cylinder 2, and then enters the reheater of boiler 1. From the reheater outlet of boiler 1, the superheated steam is extracted again, throttled by the second throttle valve 13, and then enters the preheater 17 of the methanol reforming hydrogen production system to release heat, and then merges with the exhaust steam of the medium-pressure cylinder 3.

[0042] The exhaust steam from the low-pressure cylinder 4 in the steam turbine steam cycle power generation system enters the condenser 6 for heat exchange, passes through the condensate pump 7, and then passes through the low-pressure heater 8, the deaerator 9 and the feed water pump 10, and then enters the high-pressure heater 24, and then returns to the boiler 1 in the coal-fired power generation unit.

[0043] In the steam turbine steam cycle power generation system, the extraction steam of the high-pressure cylinder 2 is introduced into the high-pressure heater 11; the extraction steam of the low-pressure cylinder 4 is introduced into the low-pressure heater 8; and the extraction steam of the medium-pressure cylinder 3 is introduced into the deaerator 9.

[0044] In the methanol reforming hydrogen production system, the methanol and desalted water mixture from the outlet of the raw material tank 14 is pressurized by the booster pump 15 and then enters the mixer 16. After mixing with the unreacted methanol and desalted water mixture from the separator 19, it enters the cold side of the preheater 17 for heat exchange to become superheated steam. Thereafter, it enters the reactor 18 to undergo a methanol-steam reforming reaction to generate hydrogen and carbon dioxide. The steam then enters the separator 19. In the separator 19, the unreacted methanol and desalted water mixture flows into the mixer 16 through a pipeline. The hydrogen and carbon dioxide enter the pressure swing adsorption device through a pipeline, where the carbon dioxide is adsorbed and the hydrogen enters the hydrogen storage tank 21 to be stored.

[0045] The temperature of the methanol and steam reforming reaction is 200~300℃, the reaction pressure is 1~5MPa, and the catalyst used is CuO / ZnO / Al2O3.

[0046] The methanol reforming reactor adopts a shell-and-tube reactor, the mixed steam of methanol and desalted water flows through the inner tube of the shell-and-tube reactor, and the superheated steam at the outlet of the boiler superheater flows through the outer tube of the shell-and-tube reactor.

[0047] The pressure of the superheated steam at the boiler superheated steam outlet after throttling is the same as the exhaust pressure of the high-pressure cylinder, and the pressure of the superheated steam at the boiler reheated steam outlet after throttling is the same as the exhaust pressure of the medium-pressure cylinder.

[0048] By reducing the air intake flow of the high-pressure cylinder and the intermediate-pressure cylinder, the operating load of the unit is reduced, so that the minimum operating load of the unit is reduced by 10%-15% from the original basis.

[0049] Rapid load change process: The boiler superheater and reheater outlets no longer input superheated steam to the methanol reforming hydrogen production system, and the methanol hydrogen production system stops working.

[0050] When the power plant receives a load increase instruction, hydrogen 21 from the hydrogen storage tank is mixed with air and enters the internal combustion engine 23 to burn and produce work, driving the second generator 26 to generate electricity, thereby rapidly increasing the load of the unit; the high-temperature exhaust gas of the internal combustion engine 23 passes through the hot side of the high-pressure heat exchanger 24 and the low-pressure heat exchanger 25 in turn to release heat, and is discharged into the atmosphere after cooling.

[0051] In the steam turbine steam cycle power generation system, a stream of condensate is drawn out from the outlet of the condensate pump 6 and enters the low-pressure heat exchanger 25 for heat exchange with the exhaust gas of the internal combustion engine 23, and then returns to the deaerator 9. By reducing the flow rate of condensate in the low-pressure heater 8, the steam extraction amount of the low-pressure cylinder 3 is reduced, and the amount of steam entering the low-pressure cylinder 3 for work is instantaneously increased, thereby quickly increasing the unit load; similarly, a stream of feed water is drawn out from the outlet of the feed water pump and enters the high-pressure heat exchanger 24 for heat exchange with the exhaust gas of the internal combustion engine 23, and then returns to the boiler 1. By reducing the flow rate of feed water in the high-pressure heater 24, the steam extraction amount of the high-pressure cylinder 24 is reduced, and the amount of steam entering the high-pressure cylinder for work is instantaneously increased, thereby quickly increasing the unit load.

[0052] Deep adjustment working process:

[0053] Close the second valve 27 and the third valve 28, open the first throttle valve 12 and the second throttle valve 13, and the superheated steam from the outlet of the superheater of the boiler 1 is split into two streams. One stream enters the methanol reforming hydrogen production system after being throttled by the first throttle valve 12, releases heat on the hot side of the reactor 18 in the methanol reforming hydrogen production system, and then merges with the exhaust steam of the high-pressure cylinder; the other stream of superheated steam enters the high-pressure cylinder 2 to expand and perform work, driving the first generator 5 to generate electricity. The exhaust steam of the high-pressure cylinder 2 merges with the superheated steam flowing through the methanol reforming hydrogen production system and then enters the reheater of the boiler 1. The superheated steam from the outlet of the boiler reheater is split into two streams. One stream enters the methanol reforming hydrogen production system after being throttled by the second throttle valve 13, releases heat on the hot side of the preheater 17 in the methanol reforming hydrogen production system, and then merges with the exhaust steam of the intermediate-pressure cylinder; the other stream expands and performs work through the intermediate-pressure cylinder 3 and the low-pressure cylinder 4 in sequence, driving the first generator 5 to generate electricity. The exhaust steam from the low-pressure cylinder 4 enters the condenser 6 for heat exchange, passes through the condensate pump 7, and then passes through the low-pressure heater 8, and then passes through the deaerator 10 and the feed water pump 10 in sequence, and then enters the high-pressure heater 11, and then returns to the boiler 1 in the coal-fired power generation unit.

[0054] In the steam turbine steam cycle power generation system, the extraction steam of the high-pressure cylinder 2 is introduced into the high-pressure heater 11; the extraction steam of the low-pressure cylinder 4 is introduced into the low-pressure heater 8; and the extraction steam of the medium-pressure cylinder 3 is introduced into the deaerator 9.

[0055] In the methanol reforming hydrogen production system, the methanol and desalted water mixture from the outlet of the raw material tank 14 is pressurized by the booster pump 15 and then enters the mixer 16. After mixing with the unreacted methanol and desalted water mixture from the separator 19, it enters the cold side of the preheater 17 for heat exchange to become superheated steam. Thereafter, it enters the reactor 18 for a methanol-steam reforming reaction to generate hydrogen and carbon dioxide. The steam then enters the separator 19. In the separator 19, the unreacted methanol and desalted water mixture flows into the mixer 16 through a pipeline. The hydrogen and carbon dioxide enter the pressure swing adsorption device 20 through a pipeline, where the carbon dioxide is adsorbed and the hydrogen enters the hydrogen storage tank 21 for storage.

[0056] Rapid load increase process:

[0057] When the power plant receives a load increase command, it closes the first and second throttle valves 12 and 13 and opens the first, second, and third valves 22, 27, and 28. At this point, the boiler's superheater and reheater outlets no longer supply superheated steam to the methanol reforming hydrogen production system, and the methanol hydrogen production system ceases operation. Hydrogen from the hydrogen storage tank 21 mixes with air and enters the internal combustion engine 23, where it burns and generates work, driving the second generator 26 to generate electricity, rapidly increasing the unit's load. The high-temperature exhaust gas from the internal combustion engine 23 passes through the hot side of the high-pressure heat exchanger 24 and the low-pressure heat exchanger 25, releasing heat before cooling and being discharged into the atmosphere.

[0058] In the steam turbine steam cycle power generation system, a stream of condensate is drawn out from the outlet of the condensate pump 7 and enters the low-pressure heat exchanger 25 for heat exchange with the exhaust gas of the internal combustion engine, and then returns to the deaerator 9. By reducing the flow rate of condensate in the low-pressure heater 8, the steam extraction amount from the low-pressure cylinder 4 is reduced, and the amount of steam entering the low-pressure cylinder 4 for work is instantaneously increased, thereby quickly increasing the unit load; similarly, a stream of feed water is drawn out from the outlet of the feed water pump 10 and enters the high-pressure heat exchanger 24 for heat exchange with the exhaust gas of the internal combustion engine 23, and then returns to the boiler 1. By reducing the flow rate of feed water in the high-pressure heater 24, the steam extraction amount of the high-pressure cylinder 2 is reduced, and the amount of steam entering the high-pressure cylinder 2 for work is instantaneously increased, thereby quickly increasing the unit load.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A coal-fired power generation system coupled with methanol to hydrogen production, characterized in that: The invention comprises a boiler (1), wherein the superheated steam of the boiler (1) is divided into two branches, one branch is connected to the steam input end of the reactor (18), and the other branch is connected to the high-pressure cylinder (2); the steam output end of the high-pressure cylinder (2) is connected to the reheated steam input end of the boiler (1), and the output end of the reheated steam is divided into two branches, one branch is connected to the hot side input end of the preheater (17), and the other branch is connected to the steam input end of the intermediate-pressure cylinder (3); the exhaust steam output end of the intermediate-pressure cylinder (3) is connected to the steam input end of the low-pressure cylinder (4), and the hot side output end of the preheater (17) is connected to the steam input end of the low-pressure cylinder (4); The steam output end of the low-pressure cylinder (4) is connected to the condenser (6), the output end of the condenser (6) is connected to the cold side input end of the low-pressure heat exchanger (25), the cold side output end of the low-pressure heat exchanger (25) is connected to the cold side input end of the high-pressure heat exchanger (24), and the cold side output end of the high-pressure heat exchanger (24) is connected to the superheated steam pipeline of the boiler (1); The gas output end of the reactor (18) is connected to a hydrogen storage tank (21), the output end of the hydrogen storage tank (21) is connected to an internal combustion engine (23), the output end of the internal combustion engine (23) is connected to the hot side input end of a high-pressure heat exchanger (24), and the hot side output end of the high-pressure heat exchanger (24) is connected to the hot side input end of a low-pressure heat exchanger (25); The output end of the condenser (6) is connected to a condensate pump (7), and the outlet of the condensate pump (7) is divided into two branches, one branch is connected to the low-pressure heater (8), and the other branch is connected to the cold side input end of the low-pressure heat exchanger (25); a third valve (28) is provided on the connecting pipeline between the condensate pump (7) and the low-pressure heat exchanger (25); The outlet of the low-pressure heater (8) and the cold-side outlet of the low-pressure heat exchanger (25) are connected to the deaerator (9) after merging, and the inlet of the deaerator (9) is also connected to the steam extraction outlet of the medium-pressure cylinder (3); the outlet of the deaerator (9) is respectively connected to the cold-side input port of the high-pressure heater (11) and the cold-side input port of the high-pressure heat exchanger (24); The outlet of the deaerator (9) is connected to the high-pressure heater (11) and the high-pressure heat exchanger (24) respectively through the feed water pump (10), and a second valve (27) is provided on the connecting pipeline between the feed water pump (10) and the high-pressure heat exchanger (24); The cold side outlet of the high-pressure heater (11) and the cold side outlet of the high-pressure heat exchanger (24) are connected to the superheated steam pipeline inlet of the boiler (1); The hydrogen and carbon dioxide outlets of the reactor (18) are connected to a separator (19), and the liquid outlet of the separator (19) is connected to the inlet of the mixer (16); The inlet of the mixer (16) is also connected to the outlet of the raw material tank (14), and a booster pump (15) is provided between the mixer (16) and the raw material tank (14); the outlet of the mixer (16) is connected to the cold side inlet of the preheater (17), and the cold side outlet of the preheater (17) is connected to the inlet of the reactor (18).

2. A coal-fired power generation system coupled with methanol to hydrogen production according to claim 1, characterized in that: The gas outlet of the separator (19) is connected to a pressure swing adsorption device (20), and the outlet of the pressure swing adsorption device (20) is connected to the inlet of a hydrogen storage tank (21).

3. The coal-fired power generation system coupled with methanol to hydrogen production according to claim 1, characterized in that: A first valve (22) is provided on the connecting pipeline between the hydrogen storage tank (21) and the internal combustion engine (23); a first throttle valve (12) is provided on the connecting pipeline between the superheated steam of the boiler (1) and the reactor (18); and a second throttle valve (13) is provided on the connecting pipeline between the reheated steam of the boiler (1) and the preheater (17).

4. An operating method of the coal-fired power generation system coupled with methanol to hydrogen production according to claim 1, characterized in that: The hydrogen storage tank (21) outputs hydrogen to the internal combustion engine (23), and the high-temperature exhaust gas output by the internal combustion engine (23) passes through the high-pressure heat exchanger (24) and the low-pressure heat exchanger (25) in sequence, and is discharged into the atmosphere after being cooled; The condensed water output from the condenser (6) exchanges heat with the exhaust gas of the internal combustion engine (23) in the low-pressure heat exchanger (25), and then enters the high-pressure heat exchanger (24) to exchange heat with the exhaust gas of the internal combustion engine (23). The water vapor after heat exchange enters the superheater of the boiler (1).

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