Electricity-hydrogen-heat multi-energy coupled power generation system and method

Abstract

The electricity-hydrogen-heat multi-energy coupled power generation system comprises a biomass system, a new energy station, a water electrolysis hydrogen production system, a coal-fired unit, a fused salt heat storage and exchange system, a hydrogen-containing fuel gas turbine power generation system and a steam turbine power generation system. The output end of the new energy station is connected with the input end of the water electrolysis hydrogen production system and the input end of the fused salt storage and heat exchange system, the output end of the coal-fired unit is connected with the input end of the fused salt storage and heat exchange system, and the output end of the biomass system and the output end of the water electrolysis hydrogen production system are both connected with the input end of the hydrogen-containing fuel gas turbine power generation system. The output end of the fused salt heat storage and exchange system is connected with the input end of the steam turbine power generation system. The power generation system is provided with the coal-fired unit, the new energy station and biogas to cooperate with multiple energy storage technologies such as heat storage and hydrogen storage, and has the advantages of improving the energy utilization rate, enhancing the stability of a power grid, reducing environmental pollution, achieving resource cyclic utilization, reducing the energy cost and the like.

Description

Technical Field

[0001] The present invention belongs to the field of electric power technology, and in particular relates to an electricity-hydrogen-heat multi-energy coupled power generation system and method. Background Art

[0002] As the proportion of new energy power generation capacity continues to increase, coal-fired power will gradually transform from the main power source to the supporting and regulating power source, which puts forward higher requirements on the flexibility of peak-shaving and frequency-regulating capabilities of coal-fired units. It is necessary to fully tap the peak-shaving and frequency-regulating potential of coal-fired units and improve the operating flexibility of coal-fired units to ensure the safe and stable operation of the power grid. The flexibility transformation of coal-fired unit boilers, which is in a low-load state during deep peak-shaving operation, has an adverse effect on the safe, stable, economical and environmentally friendly operation of coal-fired units. Therefore, it is possible to consider configuring energy storage systems for coal-fired units to achieve flexible operation of coal-fired units.

[0003] At present, the research on coupling coal-fired units with energy storage technology for peak load and frequency regulation is in its early stages. Most of the research is based on a single energy storage technology. Research on coupling coal-fired units with two or more energy storage technologies is still rare and has great limitations. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide an electric-hydrogen-heat multi-energy coupled power generation system and method.

[0005] The technical solution adopted by the present invention is: an electric-hydrogen-heat multi-energy coupled power generation system and method, including a biomass system, a new energy station, a water electrolysis hydrogen production system, a coal-fired unit, a molten salt storage and exchange system, a hydrogen-containing fuel gas turbine power generation system and a steam turbine power generation system, the output end of the new energy station is respectively connected to the water electrolysis hydrogen production system and the molten salt storage and exchange system input end, the output end of the coal-fired unit is connected to the molten salt storage and exchange system input end, the output end of the biomass system and the water electrolysis hydrogen production system are both connected to the hydrogen-containing fuel gas turbine power generation system input end, and the output of the molten salt storage and exchange system is connected to the input end of the steam turbine power generation system;

[0006] The biomass system is used to provide biomass energy;

[0007] The new energy station is used to provide new energy electricity, and the water electrolysis hydrogen production system is used to electrolyze water to produce hydrogen and oxygen according to the provided new energy electricity and store hydrogen energy and oxygen;

[0008] The coal-fired unit is used to provide electrical energy, and the molten salt heat storage and exchange system is used to perform electric-to-heat conversion and store thermal energy according to the provided new energy power or electrical energy;

[0009] The hydrogen-fueled gas turbine power generation system is used to convert at least one of biomass energy and hydrogen energy into electrical energy;

[0010] The steam turbine power generation system is used to convert thermal energy into electrical energy.

[0011] A power generation method based on the above-mentioned electric-hydrogen-heat multi-energy coupled power generation system performs any of the following power generation processes when the grid load is less than the load setting value:

[0012] 1) The coal-fired unit provides electricity, the new energy station does not provide new energy electricity, and the molten salt heat storage and exchange system converts electrical energy into thermal energy and stores it;

[0013] 2) The new energy station provides new energy electricity, the coal-fired unit does not provide electricity, and the water electrolysis hydrogen production system converts the new energy electricity into hydrogen energy and stores it;

[0014] 3) The new energy station provides new energy electricity, the coal-fired unit does not provide electricity, the water electrolysis hydrogen production system converts the new energy electricity into hydrogen energy and stores it, and the molten salt heat storage and exchange system converts the new energy electricity into heat energy and stores it;

[0015] 4) The coal-fired unit provides electricity, and the molten salt heat storage and exchange system converts the electricity into heat energy and stores it; the new energy station provides new energy electricity, and the water electrolysis hydrogen production system converts the new energy electricity into hydrogen energy and stores it.

[0016] Furthermore, it also includes executing any of the following power generation processes when the grid load is greater than or equal to the load setting value:

[0017] 1) The hydrogen energy storage capacity is greater than or equal to the hydrogen energy setting value, and the thermal energy storage capacity is greater than or equal to the thermal energy setting value. The hydrogen-fueled gas turbine power generation system converts hydrogen energy and biomass energy into electrical energy to supply power to the grid, and the steam turbine power generation system converts thermal energy into electrical energy to supply power to the grid;

[0018] 2) The hydrogen energy storage capacity is greater than or equal to the hydrogen energy setting value, and the thermal energy storage capacity is less than the thermal energy setting value, and the hydrogen-fueled gas turbine power generation system converts hydrogen energy and biomass energy into electrical energy to supply power to the grid;

[0019] 3) The hydrogen energy storage capacity is less than the hydrogen energy setting value, and the thermal energy storage capacity is greater than or equal to the thermal energy setting value, and the steam turbine power generation system converts thermal energy into electrical energy to supply power to the grid.

[0020] The beneficial effects of the present invention are:

[0021] The power generation system of the present invention is equipped with coal-fired units, new energy stations and biogas combined with various energy storage technologies such as heat storage and hydrogen storage. It has the advantages of improving energy utilization, enhancing power grid stability, reducing environmental pollution, promoting renewable energy consumption, optimizing energy structure, realizing resource recycling and reducing energy costs.

[0022] The present invention combines molten salt heat storage technology with renewable energy hydrogen production, storage and power generation technology, which improves the deep peak-shaving and frequency-regulating capabilities of coal-fired units. Molten salt heat storage technology has the advantages of large capacity and long cycle, and is widely used in heat storage in solar thermal power stations.

[0023] The power generation system of the present invention configures a molten salt heat storage system and a water electrolysis hydrogen production system for a new energy power station, converts the fluctuating new energy electricity into heat energy and hydrogen energy for storage, and reduces the wind and light abandonment rate of the new energy power station. Hydrogen energy is a secondary energy source that is abundant in source, green and low-carbon, widely used, and can be used as a large-scale long-term energy storage medium. It is an ideal interconnected medium to promote the clean and efficient use of traditional energy and support the large-scale development of renewable energy. The present invention uses renewable energy to produce hydrogen and generate electricity, which can smooth the random fluctuations of source and load and improve the flexibility of the power system.

[0024] During the peak-shaving period, the coal-fired unit of the present invention quickly converts the electricity generated by the generator of the coal-fired unit into molten salt heat through the molten salt electric heater and stores it, thereby realizing the load-reduced deep peak-shaving and rapid frequency-modulation operation of the unit; when it is necessary to increase the power generation, the molten salt heat storage and heat exchange system converts the molten salt heat into high-temperature steam heat, and generates electricity in the steam turbine; hydrogen energy and biomass energy can also be converted into electrical energy through a hydrogen-fueled gas turbine combined cycle system, thereby realizing the conversion and utilization of multiple energy sources and improving energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the power generation system of the present invention. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] like Figure 1 As shown, the present invention provides an electric-hydrogen-heat multi-energy coupled power generation system, including a biomass system, a new energy station, a water electrolysis hydrogen production system, a coal-fired unit, a molten salt storage and exchange system, a hydrogen-containing fuel gas turbine power generation system and a steam turbine power generation system, the output end of the new energy station is respectively connected to the water electrolysis hydrogen production system and the molten salt storage and exchange system input end, the output end of the coal-fired unit is connected to the molten salt storage and exchange system input end, the output end of the biomass system and the water electrolysis hydrogen production system are both connected to the hydrogen-containing fuel gas turbine power generation system input end, and the output of the molten salt storage and exchange system is connected to the input end of the steam turbine power generation system;

[0028] The biomass system is used to provide biomass energy;

[0029] The new energy station is used to provide new energy electricity, and the water electrolysis hydrogen production system is used to electrolyze water to produce hydrogen and oxygen according to the provided new energy electricity and store hydrogen energy and oxygen;

[0030] The coal-fired unit is used to provide electrical energy, and the molten salt heat storage and exchange system is used to perform electric-to-heat conversion and store thermal energy according to the provided new energy power or electrical energy;

[0031] The hydrogen-fueled gas turbine power generation system is used to convert at least one of biomass energy and hydrogen energy into electrical energy;

[0032] The steam turbine power generation system is used to convert thermal energy into electrical energy.

[0033] It can be understood that the biomass system includes a biomass biogas station, a purification unit, a valve E, and a biomass biogas booster connected in sequence, that is, the biomass biogas tank is connected to the gas inlet of the purification unit, the gas outlet of the purification unit is connected to the inlet of the biomass biogas booster through the valve E, and the outlet of the biomass biogas booster is connected to the fuel inlet pipeline of the combustion chamber of the hydrogen-containing fuel gas turbine power generation system. The function of the purification unit is to purify and remove impurities in the biogas, such as hydrogen sulfide, moisture and other pollutants.

[0034] It can be understood that a switch assembly is provided between the new energy station and the coal-fired unit and the water electrolysis hydrogen production system and the molten salt storage and heat exchange system. The switch assembly includes circuit breaker switch A, circuit breaker switch B and circuit breaker switch C. One end of the circuit breaker switch C is connected to the output end of the new energy station and one end of the circuit breaker switch B, and the other end is connected to the input end of the water electrolysis hydrogen production system. The other end of the circuit breaker switch B is connected to the input end of the molten salt storage and heat exchange system and one end of the circuit breaker switch A, and the other end of the circuit breaker switch A is connected to the output end of the coal-fired unit.

[0035] When the coal-fired unit is not involved in peak load regulation and frequency regulation, the coal-fired unit and its generator work normally. Usually, the installed capacity of the coal-fired unit is 300MW to 1000MW. At this time, the circuit breaker switch A is in the disconnected state. When the coal-fired unit is in peak load regulation and frequency regulation, the molten salt heat storage system works, the circuit breaker switch A is in the closed position, and the molten salt electric heater converts electrical energy into thermal energy and stores it in the high-temperature molten salt tank.

[0036] When the new energy power station does not participate in peak load regulation and frequency regulation, and no wind or solar power abandonment occurs, circuit breaker switch B and circuit breaker switch C are in the disconnected state. When the wind and solar resources are abundant, large-scale wind and solar power abandonment occurs in the new energy power station, and the coal-fired units do not participate in peak load regulation and frequency regulation, circuit breaker switch B and circuit breaker switch C are closed, and the new energy power station supplies power to the water electrolysis hydrogen production system and the molten salt electric heater, absorbing a large amount of new energy power. When the wind and solar resources are abundant, large-scale wind and solar power abandonment occurs in the new energy power station, and the coal-fired units participate in peak load regulation and frequency regulation, circuit breaker switch C and circuit breaker switch A are closed, and circuit breaker switch B is disconnected. The new energy power station supplies power to the water electrolysis hydrogen production equipment, and the coal-fired units supply power to the molten salt electric heater, realizing the peak load operation of the coal-fired units while absorbing a large amount of new energy power.

[0037] It can be understood that the water electrolysis hydrogen production system includes water electrolysis hydrogen production equipment, a hydrogen compression unit, an oxygen compression unit, a hydrogen storage unit, an oxygen storage unit, a hydrogen pressure reducing device and an oxygen pressure reducing device. The input end of the water electrolysis hydrogen production equipment is connected to the output end of the new energy station, and the water electrolysis hydrogen production equipment is provided with electricity by the new energy station. The hydrogen output end of the water electrolysis hydrogen production equipment is connected to the input end of the hydrogen compression unit, the output end of the hydrogen compression unit is connected to the input end of the hydrogen storage unit, and the output end of the hydrogen storage unit is connected to the input end of the hydrogen pressure reducing device through a valve C. The oxygen output end of the water electrolysis hydrogen production equipment is connected to the input end of the compression unit, the output end of the oxygen compression unit is connected to the input end of the oxygen storage unit, and the output end of the oxygen storage unit is connected to the input end of the oxygen pressure reducing device through a valve D. The output ends of the hydrogen pressure reducing device and the oxygen pressure reducing device are respectively connected to the fuel inlet and the combustion-supporting gas inlet of the combustion chamber of the hydrogen-containing fuel gas turbine power generation system. The hydrogen production technology used by the water electrolysis hydrogen production equipment can be any one of the following: alkaline water electrolysis hydrogen production technology (ALK), proton exchange membrane water electrolysis hydrogen production technology (PEM), high temperature solid oxide water electrolysis hydrogen production technology (SOEC) and anion exchange membrane water electrolysis hydrogen production technology (AEM).

[0038] It can be understood that the molten salt heat storage and exchange system includes a molten salt electric heater, a high-temperature molten salt tank, a low-temperature molten salt tank, a molten salt-steam superheater and a molten salt-steam evaporator. The input end of the molten salt electric heater is connected to the output end of the new energy station and the coal-fired unit. The molten salt electric heater can be powered by the new energy station or the coal-fired unit to operate. The high-temperature molten salt outlet of the molten salt electric heater is connected to the high-temperature molten salt inlet of the high-temperature molten salt tank, the high-temperature molten salt outlet of the high-temperature molten salt tank is connected to the high-temperature molten salt inlet of the molten salt-steam superheater, and the low-temperature molten salt outlet of the molten salt-steam superheater is connected to the molten salt -The high-temperature molten salt inlet of the steam evaporator, the low-temperature molten salt outlet of the molten salt-steam evaporator is connected to the low-temperature molten salt inlet of the low-temperature molten salt tank, the low-temperature molten salt outlet of the low-temperature molten salt tank is connected to the low-temperature molten salt inlet of the molten salt electric heater, the high-temperature steam outlet of the molten salt-steam superheater is connected to the high-temperature steam inlet of the steam turbine of the steam turbine power generation system through valve A, the low-temperature steam inlet of the molten salt-steam superheater is connected to the low-temperature steam outlet of the molten salt-steam evaporator, and the feed water inlet of the molten salt-steam evaporator is connected to the exhaust port of the steam turbine of the steam turbine power generation system through the feed water heat recovery system.

[0039] It can be understood that the hydrogen-containing fuel gas turbine power generation system includes a compressor, a combustion chamber, a hydrogen-containing fuel gas turbine and a first generator, the fuel inlet of the combustion chamber is connected to the output end of the biogas increasing device and the output end of the hydrogen pressure reducing device, the combustion-supporting gas inlet of the combustion chamber is connected to the output end of the compressor and the output end of the oxygen pressure reducing device, the compressor input end is used to communicate with the atmosphere, the combustion chamber output end is connected to the hydrogen-containing fuel gas turbine input end, and the hydrogen-containing fuel gas turbine output end is connected to the first generator.

[0040] It can be understood that the steam turbine power generation system includes a steam turbine and a second generator, the input end of the steam turbine is connected to the output end of the molten salt heat storage and exchange system, and the output end of the steam turbine is connected to the second generator.

[0041] It can be understood that a waste heat system for waste heat recovery is also provided between the hydrogen-fueled gas turbine power generation system, the molten salt heat storage and exchange system and the steam turbine power generation system. The waste heat system includes a waste heat boiler and a feed water heat recovery system. The high-temperature gas inlet of the waste heat boiler is connected to the exhaust outlet of the hydrogen-fueled gas turbine power generation system, the feed water inlet of the waste heat boiler is connected to the first feed water outlet of the feed water heat recovery system, the high-temperature steam outlet of the waste heat boiler is connected to the high-temperature steam inlet of the steam turbine of the steam turbine power generation system, the feed water inlet of the feed water heat recovery system is connected to the exhaust port of the steam turbine of the steam turbine power generation system, and the second feed water outlet of the feed water heat recovery system is connected to the feed water inlet of the molten salt-steam evaporator of the molten salt heat storage and exchange system.

[0042] Based on the above-mentioned electric-hydrogen-heat multi-energy coupled power generation system, the present invention also provides a power generation method, which performs any of the following power generation processes (i.e., stores excess electric energy) when the grid load is less than the load setting value (i.e., the grid load is low):

[0043] 1) When the grid load is very low, the new energy power station does not participate in the peak load and frequency regulation, and the coal-fired unit is in the peak load and frequency regulation, the circuit breaker switches B and C are in the disconnected state, the molten salt heat storage system is working, the circuit breaker switch A is in the closed position, and the molten salt electric heater heats the low-temperature molten salt from 290°C to 565°C high-temperature molten salt, and stores it in the high-temperature molten salt tank, realizing the function of converting electrical energy into thermal energy and storing it. Taking a 300MW coal-fired unit as an example, assuming that a peak load capacity of 30% THA is required, the peak load power is 90MW, and the working power of the molten salt electric heater at this time is 90MW. Assuming that the frequency regulation performance of the unit is to be improved, the adjustment rate is increased from 1.5% Pn / min to about 9% Pn / min (Pn takes the maximum rated capacity of the unit) by adjusting the operating power of the molten salt electric heater.

[0044] 2) When wind and solar resources are abundant and the grid load is low, and new energy power stations have small-scale wind and solar power abandonment, the new energy power stations only supply power to the water electrolysis hydrogen production equipment to achieve new energy electricity consumption and storage.

[0045] The electrolysis water hydrogen production equipment is working. Assuming that the installed capacity of the new energy power station is 200MW and the wind and solar power abandonment rate is 5%, the power of the electrolysis water hydrogen production system is 10MW, which can realize the consumption of new energy power and reduce the abandonment of wind and solar power. The hydrogen (1.6MPa) produced by the electrolysis of water is compressed by the hydrogen compression unit and stored in the hydrogen storage unit (pressure 20~45MPa). The oxygen (1.6MPa) produced by the electrolysis of water is stored in the oxygen storage unit (pressure 12~15MPa) after passing through the oxygen compression unit.

[0046] 3) When wind and solar resources are abundant and the grid load is low, new energy power stations abandon wind and solar power on a large scale, and coal-fired units do not participate in peak regulation, the new energy power stations supply power to the water electrolysis hydrogen production system and molten salt electric heaters, absorbing a large amount of new energy electricity.

[0047] At this time, circuit breaker switch A is disconnected, circuit breaker switch B and circuit breaker switch C are combined, and the water electrolysis hydrogen production equipment and molten salt electric heater are powered on. According to the remaining storable heat of the molten salt heat storage system and the remaining storable capacity of the hydrogen and oxygen storage units, the working power of the water electrolysis hydrogen production equipment and the molten salt electric heater is adjusted and allocated. For example, when the molten salt heat storage system is fully stored, the circuit breaker switch B is disconnected, and only the water electrolysis hydrogen production equipment works. Assuming that the installed capacity of the new energy power station is 200MW, and the wind and solar abandonment rate is 15%, the power of the water electrolysis hydrogen production equipment and the molten salt electric heater is 30MW. According to the actual situation and energy storage requirements of the molten salt heat storage system and the hydrogen and oxygen storage unit, the power of the water electrolysis hydrogen production equipment and the molten salt electric heater can be allocated to realize the consumption of new energy electricity and reduce the abandonment of wind and solar. The hydrogen (1.6MPa) produced by water electrolysis is compressed by the hydrogen compression unit and stored in the hydrogen storage unit (pressure 20~45MPa). The oxygen (1.6MPa) generated by water electrolysis passes through the oxygen compression unit and is stored in the oxygen storage unit (pressure 12-15MPa).

[0048] 4) When wind and solar resources are abundant and the grid load is low, and new energy power stations abandon wind and solar power on a large scale, and coal-fired units participate in peak load and frequency regulation, the new energy power station supplies power to the water electrolysis hydrogen production system, and the coal-fired units supply power to the molten salt electric heater, thereby absorbing a large amount of new energy electricity and achieving peak load operation of the coal-fired units.

[0049] At this time, circuit breaker switch A is combined, circuit breaker switch B is disconnected, and circuit breaker switch C is combined. The molten salt electric heater heats the low-temperature molten salt from 290°C to a high-temperature molten salt of 565°C and stores it in a high-temperature molten salt tank. Taking a 300MW coal-fired unit as an example, assuming that the peak-shaving capacity of 30% THA is required, the peak-shaving power is 90MW, and the working power of the molten salt electric heater at this time is 90MW. Assuming that the frequency regulation performance of the unit is to be improved, the adjustment rate is increased from 1.5% Pn / min to about 9% Pn / min (Pn takes the maximum rated capacity of the unit) by adjusting the operating power of the molten salt electric heater. At the same time, the water electrolysis hydrogen production equipment is working. Assuming that the installed capacity of the new energy power station is 200MW and the wind and solar abandonment rate is 15%, the power of the water electrolysis hydrogen production equipment is 30MW, realizing the consumption of new energy power and reducing wind and solar abandonment. The hydrogen (1.6MPa) produced by water electrolysis is compressed by the hydrogen compression unit and stored in the hydrogen storage unit (pressure 20~45MPa). The oxygen (1.6MPa) generated by water electrolysis passes through the oxygen compression unit and is stored in the oxygen storage unit (pressure 12-15MPa).

[0050] The power generation method of the present invention further includes executing any of the following power generation processes (i.e., converting the stored thermal energy and hydrogen energy into electrical energy and supplying it to the power grid) when the power grid load is greater than or equal to the load setting value (i.e., the power grid load is high):

[0051] 5) When the grid load is high and the molten salt heat storage and exchange system and steam turbine generator alone, or the hydrogen-fueled gas turbine power generation system alone cannot meet the peak power generation requirements, if the hydrogen energy storage capacity is greater than or equal to the hydrogen energy set value, and the thermal energy storage capacity is greater than or equal to the thermal energy set value, the molten salt heat storage and exchange system and the steam turbine, as well as the hydrogen-fueled gas turbine power generation system are started at the same time for peak power generation.

[0052] At this time, valve C is opened, and the hydrogen enters the combustion chamber after being decompressed to about 1.5-2.5MPa by the hydrogen decompression device. After the biomass biogas (usually at a pressure of 0.02-0.5MPa) produced by the biogas digester passes through the purification unit, valve E is opened, and the biomass biogas (CH4) is pressurized to about 1.5-2.5MPa by the biomass biogas booster device, and then mixed with hydrogen and enters the combustion chamber. By adjusting the opening of valves C and E, the ratio of hydrogen and biogas entering the combustion chamber is adjusted. The ratio of hydrogen mass to total fuel gas mass can be adjusted in the range of 0-100%.

[0053] When valve D is opened, oxygen is decompressed to 1.5-2.5MPa by the oxygen decompression device and enters the combustion chamber after mixing with air. When valve F is opened, air enters the compressor and after being pressurized, the pressure is 1.5-2.5MPa and enters the combustion chamber after mixing with oxygen. By adjusting the opening of valves D and F, the ratio of air and oxygen entering the combustion chamber can be adjusted. The ratio of oxygen mass to total combustion-supporting gas mass can be adjusted in the range of 0-100%.

[0054] After the hydrogen-containing fuel gas and oxygen-rich combustion air are burned in the combustion chamber, they enter the hydrogen-containing fuel gas turbine to perform work and generate electricity through the generator. After the work is completed, the exhaust gas (exhaust temperature is 565-600°C) enters the waste heat boiler for heat exchange.

[0055] Valve A and valve B are opened, and the water flow is distributed by adjusting the opening of valve A and valve B. The feed water flows through the molten salt-steam evaporator and molten salt-steam superheater in sequence, and is heated by high-temperature molten salt to superheated steam (560°C). After mixing with the superheated steam from the waste heat boiler, it enters the steam turbine to do work and generates electricity through the generator. The exhaust steam of the steam turbine enters the feed water heat recovery system and is heated to 285°C, and then enters the molten salt-steam evaporator to complete the cycle.

[0056] The other feed water enters the waste heat boiler after passing through valve B, where it is heated to 560°C to become superheated steam. After mixing with the superheated steam from the molten salt-steam superheater, it enters the steam turbine to perform work and generates electricity through the generator. The exhaust steam from the steam turbine enters the feed water heat recovery system and is heated to 285°C. It then passes through valve B and enters the waste heat boiler to complete the cycle.

[0057] Through the above process, if the output power of the hydrogen-fueled gas turbine is 100MW and the output power of the steam turbine is 90MW, the total output power of the hydrogen-fueled gas turbine power generation system and the steam turbine power generation system is 190MW, which can achieve a peak power generation capacity of 63% THA (based on a 300MW coal-fired unit).

[0058] 6) When the molten salt heat storage and exchange system has insufficient heat storage capacity, but sufficient hydrogen and oxygen storage capacity, that is, the hydrogen energy storage capacity is greater than or equal to the hydrogen energy setting value, and the thermal energy storage capacity is less than the thermal energy setting value, the hydrogen-fueled gas turbine power generation system is started to generate electricity, and the molten salt heat storage and exchange system does not work.

[0059] At this time, valve C is opened, and hydrogen enters the combustion chamber after being decompressed to about 1.5-2.5MPa by the hydrogen decompression device. After the biogas (usually at a pressure of 0.02-0.5MPa) produced by the biogas digester passes through the purification unit, valve E is opened, and the biogas (CH4) is pressurized to about 1.5-2.5MPa by the biogas booster device, and then mixed with hydrogen and enters the combustion chamber. By adjusting the opening of valves C and E, the ratio of hydrogen and biogas entering the combustion chamber is adjusted. The ratio of hydrogen mass to total fuel gas mass can be adjusted in the range of 0-100%. When pure hydrogen or a high proportion of hydrogen is used for combustion, CO2 in the combustion products is greatly reduced, which can reduce carbon emissions.

[0060] When valve D is opened, oxygen is decompressed to 1.5-2.5MPa by the oxygen decompression device, and then mixed with air and enters the combustion chamber. When valve F is opened, air enters the compressor, and after being pressurized, the pressure is 1.5-2.5MPa, and then mixed with oxygen and enters the combustion chamber. By adjusting the opening of valves D and F, the ratio of air and oxygen entering the combustion chamber can be adjusted. The adjustable range of the ratio of oxygen mass to the total combustion-supporting gas mass is 0-100%. The use of oxygen-enriched combustion can increase the concentration of CO2 in the combustion products, making it easier to capture and seal. At the same time, oxygen-enriched combustion can also solve the problem of nitrogen oxide (NOx) emissions in the combustion process of traditional gas turbines, because the use of pure oxygen for combustion can avoid the participation of nitrogen in the air in the reaction, thereby reducing the generation of NOx.

[0061] After the hydrogen-containing fuel gas and oxygen-enriched combustion air are burned in the combustion chamber, they enter the hydrogen-containing fuel gas turbine to perform work and generate electricity through the generator. After the work is completed, the exhaust gas (exhaust temperature is 565-600°C) enters the waste heat boiler for heat exchange. Valve B is opened, valve A is closed, and the outlet water of the feed water heat recovery system enters the waste heat boiler after passing through valve B, and is heated to 560°C to become superheated steam. Subsequently, the superheated steam drives the steam turbine to perform work and generate electricity. The exhaust steam of the steam turbine enters the feed water heat recovery system and is heated to 285°C, and then enters the waste heat boiler through valve B to complete the cycle.

[0062] Through the above process, if the output power of the hydrogen-fueled gas turbine is 100MW and the output power of the steam turbine is 50MW, the output power of the hydrogen-fueled gas turbine combined cycle system is 150MW, which can achieve 50% THA's peak power generation capacity (based on a 300MW coal-fired unit).

[0063] 7) When the storage capacity of hydrogen and oxygen is insufficient, but the heat storage capacity of the molten salt heat storage and exchange system is sufficient, the hydrogen energy storage capacity is less than the hydrogen energy setting value, and the heat energy storage capacity is greater than or equal to the heat energy setting value, the molten salt heat storage and exchange system and the steam turbine are started to generate electricity, and the hydrogen fuel gas turbine power generation system does not work.

[0064] The steam turbine power generation system is put into operation, valve A is opened, valve B is closed, the high-temperature steam (560°C) at the outlet of the molten salt-steam superheater enters the steam turbine to perform work and generates electricity through the generator, the exhaust steam of the steam turbine enters the feed water heat recovery system and is heated to 285°C, and then flows through the molten salt-steam evaporator and the molten salt-steam superheater in turn, and is heated by the high-temperature molten salt to become superheated high-temperature steam (560°C). Through the above process, if the output power of the steam turbine power generation system is 90MW, it can achieve a peak power generation capacity of 30% THA (based on a 300MW coal-fired unit).

[0065] 8) When the power grid needs a rapid load increase response, the hydrogen-fueled gas turbine power generation system is started to generate electricity.

[0066] At this time, valve C and valve D are opened, and hydrogen and oxygen are respectively mixed with biomass gas and air after being decompressed, and burned in the combustion chamber. Then, the high-temperature and high-pressure gas drives the hydrogen-containing fuel gas turbine to generate electricity, rapidly increasing the power generation output. The hydrogen-containing fuel gas turbine has the performance of rapid start and stop (5 minutes to start) and rapid load increase, and the rapid load increase capacity can reach 40MW / min.

[0067] The above-mentioned hydrogen energy setting value, thermal energy setting value, and load setting value may be the same or different in different power generation processes, and are set specifically according to actual needs.

[0068] In summary, the present invention utilizes coal-fired units with molten salt heat storage and exchange and steam turbine power generation, and couples new energy, hydrogen energy, and biomass energy, and utilizes hydrogen-fueled gas turbine combined cycle system power generation technology to achieve deep peak regulation and peak operation of coal-fired units. The deep peak regulation capacity can reach 30%, and the peak operation can reach 163%, which greatly improves the operation flexibility and safety of large coal-fired units. At the same time, the use of new energy power hydrogen production and heat storage technology realizes the consumption of new energy power and reduces the abandonment rate of wind and solar power. The electric-hydrogen-heat multi-energy coupled power generation system and method proposed by the present invention strongly supports the consumption of new energy and the safe and stable operation of new power systems.

[0069] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

Claims

1. An electricity-hydrogen-heat multi-energy coupled power generation system, characterized in that: It includes a biomass system, a new energy station, a water electrolysis hydrogen production system, a coal-fired unit, a molten salt storage and heat exchange system, a hydrogen-containing fuel gas turbine power generation system and a steam turbine power generation system, wherein the output end of the new energy station is respectively connected to the water electrolysis hydrogen production system and the molten salt storage and heat exchange system input end, the output end of the coal-fired unit is connected to the molten salt storage and heat exchange system input end, the output ends of the biomass system and the water electrolysis hydrogen production system are both connected to the hydrogen-containing fuel gas turbine power generation system input end, and the output of the molten salt storage and heat exchange system is connected to the input end of the steam turbine power generation system; The biomass system is used to provide biomass energy; The new energy station is used to provide new energy electricity, and the water electrolysis hydrogen production system is used to electrolyze water to produce hydrogen and oxygen according to the provided new energy electricity and store hydrogen energy and oxygen; The coal-fired unit is used to provide electrical energy, and the molten salt heat storage and exchange system is used to perform electric-to-heat conversion and store thermal energy according to the provided new energy power or electrical energy; The hydrogen-fueled gas turbine power generation system is used to convert at least one of biomass energy and hydrogen energy into electrical energy; The steam turbine power generation system is used to convert thermal energy into electrical energy.

2. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: The biomass system comprises a biomass biogas station, a purification processing unit, a valve E, and a biomass biogas boosting device which are connected in sequence, and the output end of the biomass biogas boosting device is connected to the input end of a hydrogen-containing fuel gas turbine power generation system.

3. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: A switch assembly is provided between the new energy station and the coal-fired unit and the water electrolysis hydrogen production system and the molten salt storage and heat exchange system. The switch assembly includes a circuit breaker switch A, a circuit breaker switch B and a circuit breaker switch C. One end of the circuit breaker switch C is connected to the output end of the new energy station and one end of the circuit breaker switch B, and the other end is connected to the input end of the water electrolysis hydrogen production system. The other end of the circuit breaker switch B is connected to the input end of the molten salt storage and heat exchange system and one end of the circuit breaker switch A. The other end of the circuit breaker switch A is connected to the output end of the coal-fired unit.

4. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: The water electrolysis hydrogen production system comprises water electrolysis hydrogen production equipment, a hydrogen compression unit, an oxygen compression unit, a hydrogen storage unit, an oxygen storage unit, a hydrogen pressure reducing device and an oxygen pressure reducing device. The input end of the water electrolysis hydrogen production equipment is connected to the output end of the new energy station, the hydrogen output end of the water electrolysis hydrogen production equipment is connected to the input end of the hydrogen compression unit, the output end of the hydrogen compression unit is connected to the input end of the hydrogen storage unit, the output end of the hydrogen storage unit is connected to the input end of the hydrogen pressure reducing device, the oxygen output end of the water electrolysis hydrogen production equipment is connected to the input end of the compression unit, the output end of the oxygen compression unit is connected to the input end of the oxygen storage unit, the output end of the oxygen storage unit is connected to the input end of the oxygen pressure reducing device, and the output ends of the hydrogen pressure reducing unit and the oxygen pressure reducing unit are both connected to the input end of the hydrogen-containing fuel gas turbine power generation system.

5. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: The molten salt heat storage and exchange system includes a molten salt electric heater, a high-temperature molten salt tank, a low-temperature molten salt tank, a molten salt-steam superheater and a molten salt-steam evaporator. The input end of the molten salt electric heater is connected to the output end of the new energy station and the coal-fired unit, the high-temperature molten salt outlet of the molten salt electric heater is connected to the high-temperature molten salt inlet of the high-temperature molten salt tank, the high-temperature molten salt outlet of the high-temperature molten salt tank is connected to the high-temperature molten salt inlet of the molten salt-steam superheater, the low-temperature molten salt outlet of the molten salt-steam superheater is connected to the high-temperature molten salt inlet of the molten salt-steam evaporator, the low-temperature molten salt outlet of the molten salt-steam evaporator is connected to the low-temperature molten salt inlet of the low-temperature molten salt tank, the low-temperature molten salt outlet of the low-temperature molten salt tank is connected to the low-temperature molten salt inlet of the molten salt electric heater, the high-temperature steam outlet of the molten salt-steam superheater is connected to the input end of the steam turbine power generation system, the low-temperature steam inlet of the molten salt-steam superheater is connected to the low-temperature steam outlet of the molten salt-steam evaporator, and the feed water inlet of the molten salt-steam evaporator is connected to the exhaust port of the steam turbine power generation system.

6. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: The hydrogen-containing fuel gas turbine power generation system comprises a compressor, a combustion chamber, a hydrogen-containing fuel gas turbine and a first generator, wherein the input end of the combustion chamber is connected to a biomass system, a water electrolysis hydrogen production system and an output end of the compressor, the compressor input end is used to communicate with the atmosphere, the combustion chamber output end is connected to the hydrogen-containing fuel gas turbine input end, and the hydrogen-containing fuel gas turbine output end is connected to the first generator.

7. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: The steam turbine power generation system comprises a steam turbine and a second generator, wherein the input end of the steam turbine is connected to the output end of the molten salt heat storage and exchange system, and the output end of the steam turbine is connected to the second generator.

8. The electric-hydrogen-heat multi-energy coupled power generation system and method according to claim 1, characterized in that: A waste heat system for waste heat recovery is also provided between the hydrogen-fueled gas turbine power generation system and the molten salt heat storage and exchange system and the steam turbine power generation system. The waste heat system includes a waste heat boiler and a feed water heat recovery system. The high-temperature gas inlet of the waste heat boiler is connected to the exhaust outlet of the hydrogen-fueled gas turbine power generation system, the feed water inlet of the waste heat boiler is connected to the first feed water outlet of the feed water heat recovery system, the high-temperature steam outlet of the waste heat boiler is connected to the high-temperature steam inlet of the steam turbine of the steam turbine power generation system, the feed water inlet of the feed water heat recovery system is connected to the exhaust port of the steam turbine of the steam turbine power generation system, and the second feed water outlet of the feed water heat recovery system is connected to the feed water inlet of the molten salt-steam evaporator of the molten salt heat storage and exchange system.

9. A power generation method based on the electric-hydrogen-heat multi-energy coupled power generation system according to claim 1, characterized in that: When the grid load is less than the load setting value, any of the following power generation processes is performed: 1) The coal-fired unit provides electricity, the new energy station does not provide new energy electricity, and the molten salt heat storage and exchange system converts electrical energy into thermal energy and stores it; 2) The new energy station provides new energy electricity, the coal-fired unit does not provide electricity, and the water electrolysis hydrogen production system converts the new energy electricity into hydrogen energy and stores it; 3) The new energy station provides new energy electricity, the coal-fired unit does not provide electricity, the water electrolysis hydrogen production system converts the new energy electricity into hydrogen energy and stores it, and the molten salt heat storage and exchange system converts the new energy electricity into heat energy and stores it; 4) The coal-fired unit provides electricity, and the molten salt heat storage and exchange system converts the electricity into heat energy and stores it; the new energy station provides new energy electricity, and the water electrolysis hydrogen production system converts the new energy electricity into hydrogen energy and stores it.

10. The power generation method according to claim 9, characterized in that: It also includes executing any of the following power generation processes when the grid load is greater than or equal to the load setting value: 1) The hydrogen energy storage capacity is greater than or equal to the hydrogen energy setting value, and the thermal energy storage capacity is greater than or equal to the thermal energy setting value. The hydrogen-fueled gas turbine power generation system converts hydrogen energy and biomass energy into electrical energy to supply power to the grid, and the steam turbine power generation system converts thermal energy into electrical energy to supply power to the grid; 2) The hydrogen energy storage capacity is greater than or equal to the hydrogen energy setting value, and the thermal energy storage capacity is less than the thermal energy setting value, and the hydrogen-fueled gas turbine power generation system converts hydrogen energy and biomass energy into electrical energy to supply power to the grid; 3) The hydrogen energy storage capacity is less than the hydrogen energy setting value, and the thermal energy storage capacity is greater than or equal to the thermal energy setting value, and the steam turbine power generation system converts thermal energy into electrical energy to supply power to the grid.

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