Gas-steam combined cycle power generation system and method coupled with thermochemical energy storage

Abstract

The invention discloses a gas-steam combined cycle power generation system and method coupled with thermochemical energy storage. Comprising a Ca (OH) 2 / CaO system thermochemical energy storage system, a high-pressure natural gas conveying pipeline, a natural gas differential pressure power generation system, a gas turbine power generation system, a waste heat boiler, a frequency division fluid preheater, a steam turbine power generation system, a water supply preheater, a valve A, a valve B, a valve C, an air preheater and a valve D, the Ca (OH) 2 / CaO system thermochemical energy storage system comprises a reactor body and a steam pocket, the system and the method can deeply integrate thermochemical energy storage, solar full spectrum utilization and pressure energy recovery, and meanwhile, multi-energy coupling and dynamic peak regulation can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of combined cycle power generation and relates to a gas-steam combined cycle power generation system and method coupled with thermochemical energy storage. Background Technology

[0002] Gas-steam combined cycle power generation systems have become the mainstream technology for modern thermal power generation due to their high efficiency and low emissions. However, with the large-scale grid connection of new energy sources and the increasing demand for grid peak shaving, traditional combined cycle systems still face the following technical bottlenecks: Insufficient peak-shaving capacity: Gas turbines are limited to minimum technical output and need to operate at reduced load during deep peak shaving, resulting in a significant decrease in thermal efficiency and deterioration in economic performance; Although the steam side can be adjusted by increasing or decreasing steam flow, the response speed is slow and it is limited by the waste heat recovery of the waste heat boiler.

[0003] Low overall energy utilization efficiency: After high-pressure natural gas is transported to the power plant, it needs to be depressurized at a pressure reducing station, resulting in a large amount of pressure energy being wasted; at the same time, the solar energy resources around the plant area are not fully integrated, and the energy conversion efficiency of conventional photovoltaic or solar thermal systems is limited.

[0004] Poor adaptability of energy storage technologies: Existing technologies such as molten salt thermal energy storage suffer from problems such as high-temperature corrosion and large heat loss, and are difficult to couple efficiently with steam systems. The application of chemical energy storage in combined cycle systems is mostly concentrated in the field of fuel reforming, and there is a lack of rapid response energy storage solutions for steam-side thermodynamic cycles.

[0005] Lack of system synergy optimization: Subsystems such as solar preheating, waste heat recovery, and energy storage and release operate independently, leading to improper matching of heat energy quality. For example, compressed air preheating and boiler feedwater heating require different temperature ranges, but traditional designs have not achieved cascaded utilization.

[0006] In recent years, although some research has attempted to introduce solar-assisted or compressed air energy storage, three major drawbacks remain: solar energy is utilized only in the form of photovoltaics or solar thermal, and full-spectrum frequency division technology has not been applied to combined cycle systems; energy storage systems mostly use physical thermal storage, resulting in low energy density and limited energy release temperature, making it impossible to directly improve steam parameters; and the natural gas pressure energy recovery device lacks integrated design with the combustion system, and the pressure-reducing power generation link is not included in the overall energy flow optimization. Therefore, there is an urgent need to develop a novel combined cycle system that deeply integrates thermochemical energy storage, full-spectrum solar energy utilization, and pressure energy recovery, and to overcome the limitations of existing technologies on flexibility, efficiency, and grid support capabilities through multi-energy coupling and dynamic peak-shaving strategies. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gas-steam combined cycle power generation system and method that couples thermochemical energy storage. This system and method can deeply integrate thermochemical energy storage, full-spectrum utilization of solar energy and pressure energy recovery, and can also achieve multi-energy coupling and dynamic peak shaving.

[0008] To achieve the above objectives, this invention discloses a gas-steam combined cycle power generation system coupled with thermochemical energy storage, comprising a Ca(OH)2 / CaO system thermochemical energy storage system, a high-pressure natural gas transmission pipeline, a natural gas differential pressure power generation system, a gas turbine power generation system, a waste heat boiler, a frequency-controlled fluid preheater, a steam turbine power generation system, a feedwater preheater, valves A, B, and C, an air preheater, and valve D; the Ca(OH)2 / CaO system thermochemical energy storage system includes a reactor body and a steam drum; The high-pressure natural gas transmission pipeline is connected to the inlet of the natural gas differential pressure power generation system and the gas turbine power generation system. The outlet of the gas turbine power generation system is connected to the external environment through the heat release side of the waste heat boiler and the heat release side of the frequency-divided fluid preheater. The heat absorption side outlet of the waste heat boiler is divided into two paths after passing through the heat absorption side of the steam turbine power generation system and the feedwater preheater. One path is connected to the pipe-side inlet of the reactor body via valve A, and the other path is connected to the heat absorption side inlet of the waste heat boiler via valve B. The pipe-side outlet of the reactor body is connected to the heat absorption side inlet of the waste heat boiler via valve C. The outlet of the solar full-spectrum utilization system is connected to the inlet of the solar full-spectrum utilization system in sequence via the heat release side of the feedwater preheater, the heat release side of the air preheater, and the heat release side of the frequency-divided fluid preheater. The outlet of the steam drum is connected to the inlet of the steam drum via valve D, the shell side of the reactor shell, and valve E.

[0009] A further improvement of the gas-steam combined cycle power generation system coupled with thermochemical energy storage described in this invention is as follows: Furthermore, the outlet of the solar full-spectrum utilization system is connected to the inlet of the solar full-spectrum utilization system via the heat release side of the water preheater, the heat release side of the air preheater, the frequency-distributed fluid circulation pump, and the heat release side of the frequency-distributed fluid preheater.

[0010] Furthermore, the heat absorption side outlet of the waste heat boiler is divided into two paths after passing through the heat absorption side of the steam turbine power generation system, condenser, feedwater pump, and feedwater preheater.

[0011] Furthermore, a gas turbine power generation system includes a compressor, a combustion chamber, a gas turbine, and a gas turbine generator; The high-pressure natural gas transmission pipeline is connected to the inlet of the combustion chamber via the natural gas differential pressure power generation system. The outlet of the compressor is connected to the inlet of the combustion chamber, and the outlet of the combustion chamber is connected to the inlet of the gas turbine. The outlet of the gas turbine is connected to the external environment via the heat release side of the waste heat boiler and the heat release side of the frequency-diverting fluid preheater.

[0012] Furthermore, the heat absorption side outlet of the air preheater is connected to the inlet of the compressor.

[0013] Furthermore, the steam turbine power generation system includes a steam turbine and a steam turbine generator. The heat absorption side outlet of the waste heat boiler is divided into two paths after passing through the heat absorption side of the steam turbine and the feedwater preheater. The steam turbine is connected to the steam turbine generator.

[0014] Furthermore, the solar full-spectrum utilization system includes Fresnel lenses, vacuum collector tubes, and photovoltaic panels, which are distributed sequentially from top to bottom. The vacuum collector tubes are connected to the heat release side outlet of the frequency-divided fluid preheater and the heat release side inlet of the feedwater preheater.

[0015] Furthermore, in the solar radiation passing through the Fresnel lens, long-wavelength light is absorbed by the frequency-dividing fluid in the vacuum collector tube and converted into heat energy, while the remaining short-wavelength light passes through the frequency-dividing fluid in the vacuum collector tube and irradiates the photovoltaic panel for photoelectric conversion.

[0016] Furthermore, valves A, B, C, D, and E are all electrically operated regulating valves.

[0017] This invention discloses a gas-steam combined cycle power generation method coupled with thermochemical energy storage, comprising the following steps: Let the power generation of the natural gas differential pressure power generation system, the gas turbine power generation system, the steam turbine power generation system, and the solar full-spectrum utilization system be P1, P2, P3, and P4, respectively. Then the maximum power generation of the system is P = P1 + P2 + P3 + P4. When P1+P2+P3 < actual power consumption When P1+P2+P3+P4 is less than or equal to P4, the electricity generated by the natural gas differential pressure power generation system, gas turbine power generation system, steam turbine power generation system, and solar full-spectrum utilization system will all be used for electricity users. When the actual electricity consumption When P1+P2+P3 <=, the electrical energy P4 generated by the solar full-spectrum utilization system is connected to the Ca(OH)2 / CaO thermochemical energy storage system, and valves A, C and D are closed, while valves B and E are opened to convert electrical energy P4 into chemical energy and store it in the Ca(OH)2 / CaO thermochemical energy storage system. When the actual electricity consumption When P2+P3 <=, the electrical energy P1+P4 generated by the natural gas pressure differential power generation system and the solar full-spectrum utilization system is connected to the Ca(OH)2 / CaO system thermochemical energy storage system. Valves A, C and D are closed, and valves B and E are opened to convert the electrical energy P1+P4 into chemical energy and store it in the Ca(OH)2 / CaO system thermochemical energy storage system. When the actual electricity consumption When P2 <=, the electrical energy P1+P3+P4 generated by the natural gas pressure differential power generation system, the steam turbine power generation system, and the solar full-spectrum utilization system is connected to the Ca(OH)2 / CaO thermochemical energy storage system. Valves A, C, and D are closed, and valves B and E are opened to convert the electrical energy P1+P3+P4 into chemical energy and store it in the Ca(OH)2 / CaO thermochemical energy storage system. When the actual electricity consumption When P1+P2+P3+P4 is greater than or equal to P4, valves A, C, and D are opened, while valves B and E are closed. Water vapor from the steam drum is then introduced into the shell side of the reactor body, where it reacts chemically with CaO and releases heat. Feedwater flowing from the feedwater preheater outlet first enters the tube side of the reactor body through valve A to absorb chemical heat, and then enters the waste heat boiler through valve C for heat exchange. This converts the chemical energy stored in the Ca(OH)2 / CaO thermochemical energy storage system into the thermal energy of the water vapor. Simultaneously, the output of the feedwater pump is increased, increasing the steam flow rate and improving the power generation of the steam turbine power generation system.

[0018] The present invention has the following beneficial effects: In practical operation, the gas-steam combined cycle power generation system and method with coupled thermochemical energy storage described in this invention allocates the power generation of the natural gas pressure differential power generation system, the gas turbine power generation system, the steam turbine power generation system, and the solar full-spectrum utilization system according to the actual power consumption, so as to achieve deep integration of thermochemical energy storage, solar full-spectrum utilization, and pressure energy recovery. At the same time, it can realize multi-energy coupling and dynamic peak shaving, which is extremely practical. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a structural diagram of the present invention.

[0020] Among them, 1 is a high-pressure natural gas transmission pipeline, 2 is a natural gas differential pressure power generation system, 3 is a gas turbine power generation system, 4 is a waste heat boiler, 5 is a steam turbine power generation system, 6 is a solar full-spectrum utilization system, 7 is a Ca(OH)2 / CaO system thermochemical energy storage system, 8 is air, 9 is an air preheater, 10 is a condenser, 11 is a feedwater pump, 12 is a feedwater preheater, 13 is valve A, 14 is valve B, 15 is valve C, 16 is valve D, 17 is valve E, 18 is a frequency-distributed fluid preheater, 19 is a frequency-distributed fluid circulation pump, 3-1 is a compressor, 3-2 is a combustion chamber, 3-3 is a gas turbine, 3-4 is a gas turbine generator, 5-1 is a steam turbine, 5-2 is a steam turbine generator, 6-1 is a Fresnel lens, 6-2 is a vacuum heat collection tube, 6-3 is a photovoltaic power generation panel, 7-1 is the reactor body, and 7-2 is the steam drum. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0025] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0026] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] Example 1 refer to Figure 1The gas-steam combined cycle power generation system coupled with thermochemical energy storage described in this invention includes a high-pressure natural gas transmission pipeline 1, a natural gas differential pressure power generation system 2, a gas turbine power generation system 3, a waste heat boiler 4, a steam turbine power generation system 5, a full-spectrum solar energy utilization system 6, a Ca(OH)2 / CaO system thermochemical energy storage system 7, an air preheater 9, a condenser 10, a feedwater pump 11, a feedwater preheater 12, valves A13, B14, C15, D16, and E17. Frequency-divided fluid preheater 18 and frequency-divided fluid circulation pump 19; gas turbine power generation system 3 includes compressor 3-1, combustion chamber 3-2, gas turbine 3-3 and gas turbine generator 3-4; steam turbine power generation system 5 includes steam turbine 5-1 and steam turbine generator 5-2; solar full-spectrum utilization system 6 includes Fresnel lens 6-1, vacuum collector tube 6-2 and photovoltaic power generation panel 6-3; Ca(OH)2 / CaO system thermochemical energy storage system 7 includes reactor body 7-1 and steam drum 7-2; The high-pressure natural gas transmission pipeline 1 is connected to the inlet of the combustion chamber 3-2 via the natural gas differential pressure power generation system 2. The outlet of the compressor 3-1 is connected to the inlet of the combustion chamber 3-2. The outlet of the combustion chamber 3-2 is connected to the inlet of the gas turbine 3-3. The outlet of the gas turbine 3-3 is connected to the external environment via the heat release side of the waste heat boiler 4 and the heat release side of the frequency-divided fluid preheater 18.

[0030] The heat absorption side outlet of the waste heat boiler 4 is connected to the inlet of the steam turbine 5-1. The outlet of the steam turbine 5-1 is divided into two paths after passing through the heat absorption side of the condenser 10, the feed water pump 11, and the feed water preheater 12. One path is connected to the pipe side inlet of the reactor body 7-1 via valve A13, and the other path is connected to the heat absorption side inlet of the waste heat boiler 4 via valve B14. The pipe side outlet of the reactor body 7-1 is connected to the heat absorption side inlet of the waste heat boiler 4 via valve C15.

[0031] The heat absorption side outlet of the air preheater 9 is connected to the inlet of the compressor 3-1.

[0032] The outlet of the solar full-spectrum utilization system 6 is connected to the inlet of the solar full-spectrum utilization system 6 in sequence via the heat release side of the water preheater 12, the heat release side of the air preheater 9, the heat release side of the frequency-distributed fluid circulation pump 19 and the heat release side of the frequency-distributed fluid preheater 18.

[0033] The outlet of steam drum 7-2 is connected to the inlet of steam drum 7-2 via valve D16, the shell side of the reactor shell, and valve E17.

[0034] The solar full-spectrum utilization system 6 includes a Fresnel lens 6-1, a vacuum heat collection tube 6-2, and a photovoltaic power generation panel 6-3. The Fresnel lens 6-1, the vacuum heat collection tube 6-2, and the photovoltaic power generation panel 6-3 are distributed from top to bottom. The vacuum heat collection tube 6-2 is connected to the heat release side outlet of the frequency-divided fluid preheater 18 and the heat release side inlet of the feedwater preheater 12.

[0035] The gas-steam combined cycle power generation method coupled with thermochemical energy storage according to the present invention includes the following steps: High-pressure natural gas flowing from high-pressure natural gas pipeline 1 first enters the natural gas differential pressure power generation system 2 to generate electricity. It then enters combustion chamber 3-2 and mixes with air compressed by compressor 3-1 to produce high-temperature, high-pressure gas. This high-temperature, high-pressure gas drives gas turbine 3-3 to perform work and drives gas turbine generator 3-4 to generate electricity. After completing its work, the gas flows out of gas turbine 3-3 and first enters waste heat boiler 4 for heat exchange, heating the feedwater into high-temperature steam. Then, the steam exits from the waste heat boiler 4 through the flue gas outlet. The steam discharged from the chimney enters the frequency-controlled fluid preheater 18 for further heat exchange, transferring as much heat as possible to the frequency-controlled fluid. The high-temperature steam generated in the waste heat boiler 4 drives the steam turbine 5-1 to perform work and powers the steam generator 5-2 to generate electricity. After completing its work, the steam exits the steam turbine 5-1 and enters the condenser 10 for heat exchange, then is pumped back into the waste heat boiler 4 via the feedwater pump 11 for circulation. The water exiting the feedwater pump 11 is preheated by the feedwater preheater 12 before entering the waste heat boiler 4, thereby increasing the boiler's heat transfer efficiency. The boiler feedwater temperature is adjusted to reduce the gas consumption of the waste heat boiler 4; air is preheated by air preheater 9 before entering compressor 3-1, thereby increasing the air temperature and reducing the power consumption of compressor 3-1; in the solar radiation passing through Fresnel lens 6-1, long-wavelength light is absorbed and converted into heat energy by the frequency-dividing fluid in vacuum collector tube 6-2, while the remaining short-wavelength light passes through the frequency-dividing fluid in vacuum collector tube 6-2 and irradiates photovoltaic panel 6-3 for photoelectric conversion, thus realizing a solar-driven cogeneration process. The frequency-divided fluid flowing into the vacuum collector tube 6-2 absorbs heat energy and then flows out of the vacuum collector tube 6-2 outlet. It then passes through the feedwater preheater 12 and the air preheater 9 in sequence to transfer the heat energy to the feedwater and air of the waste heat boiler 4. The low-temperature frequency-divided fluid flowing out of the air preheater 9 will be pumped back into the vacuum collector tube 6-2 through the frequency-divided fluid circulation pump 19 for circulating heat absorption. The frequency-divided fluid is preheated by the frequency-divided fluid preheater 18 before flowing into the vacuum collector tube 6-2 to fully recover the waste heat of the system.

[0036] The electricity generated in the natural gas differential pressure power generation system 2, the gas turbine power generation system 3, the steam turbine power generation system 5, and the solar full-spectrum utilization system 6 will be supplied to electricity users. When the Ca(OH)2 / CaO system thermochemical energy storage system 7 is in the energy storage stage, the reactor body 7-1, as an electricity user, consumes the system's electrical energy. The Ca(OH)2 inside it decomposes to generate CaO and water vapor. The generated water vapor enters the steam drum 7-2 from the shell side of the reactor body 7-1 through valve E17, thereby converting electrical energy into chemical energy stored in Ca(OH)2. In the Ca(OH)2 / CaO thermochemical energy storage system 7, when the Ca(OH)2 / CaO thermochemical energy storage system 7 is in the energy release stage, the water vapor in the steam drum 7-2 enters the shell side of the reactor body 7-1 through valve D16, reacts chemically with CaO and releases heat. At this time, the feedwater flowing out from the outlet of the feedwater preheater 12 does not directly enter the waste heat boiler 4 through valve B14 for heat exchange, but enters the tube side of the reactor body 7-1 through valve A13 to absorb chemical heat, and then enters the waste heat boiler 4 through valve C15 for heat exchange.

[0037] Let the power generation of the natural gas pressure differential power generation system 2, the gas turbine power generation system 3, the steam turbine power generation system 5, and the solar full-spectrum utilization system 6 be P1, P2, P3, and P4, respectively. Then the maximum power generation of the system is P = P1 + P2 + P3 + P4.

[0038] When P1+P2+P3 < actual power consumption When P1+P2+P3+P4 is less than or equal to P4, the electricity generated by the natural gas pressure differential power generation system 2, the gas turbine power generation system 3, the steam turbine power generation system 5, and the solar full-spectrum utilization system 6 will all be used for electricity users.

[0039] When the actual electricity consumption When P1 + P2 + P3 is less than or equal to P3, the electrical energy P4 generated by the full-spectrum solar energy utilization system 6 is connected to the Ca(OH)2 / CaO thermochemical energy storage system 7, and valves A13, C15 and D16 are closed, while valves B14 and E17 are opened, thereby converting the electrical energy P4 into chemical energy and storing it in the Ca(OH)2 / CaO thermochemical energy storage system 7.

[0040] When the actual electricity consumption When P2+P3 <=, the electrical energy P1+P4 generated by the natural gas pressure differential power generation system 2 and the solar full-spectrum utilization system 6 is connected to the Ca(OH)2 / CaO system thermochemical energy storage system 7, and valves A13, C15 and D16 are closed, while valves B14 and E17 are opened, thereby converting the electrical energy P1+P4 into chemical energy and storing it in the Ca(OH)2 / CaO system thermochemical energy storage system 7.

[0041] When the actual electricity consumption When P2 <=, the electrical energy P1+P3+P4 generated by the natural gas pressure differential power generation system 2, the steam turbine power generation system 5, and the solar full-spectrum utilization system 6 is connected to the Ca(OH)2 / CaO system thermochemical energy storage system 7. Valves A13, C15, and D16 are closed, and valves B14 and E17 are opened, thereby converting the electrical energy P1+P3+P4 into chemical energy and storing it in the Ca(OH)2 / CaO system thermochemical energy storage system 7.

[0042] When the actual electricity consumption When P1+P2+P3+P4 is greater than or equal to P4, valves A13, C15, and D16 are opened, while valves B14 and E17 are closed. This allows steam from the steam drum 7-2 to be introduced into the shell side of the reactor body 7-1, where it reacts chemically with CaO and releases heat. Feedwater flowing from the outlet of the feedwater preheater 12 enters the pipe side of the reactor body 7-1 through valve A13 to absorb chemical heat, and then enters the waste heat boiler 4 through valve C15 for heat exchange. This converts the chemical energy stored in the Ca(OH)2 / CaO thermochemical energy storage system 7 into the thermal energy of steam, increasing the steam temperature and thus the power generation efficiency of the steam turbine power generation system 5. Simultaneously, the output of the feedwater pump 11 can be increased to increase the steam flow rate and improve the power generation of the steam turbine power generation system 5.

[0043] In this embodiment, valves A13, B14, C15, D16, and E17 are all electric regulating valves. In actual operation, the valve opening can be adjusted according to the actual situation to match the different power demand of the power plant.

[0044] The high-pressure natural gas in the high-pressure natural gas transmission pipeline 1 does not need to be depressurized at the pressure reducing station before entering the combustion chamber 3-2. Instead, the natural gas pressure is reduced to the pressure required by the natural gas pressure differential power generation system 2, thus avoiding the waste of natural gas pressure energy and improving the power generation and comprehensive utilization efficiency of natural gas energy in the power plant.

[0045] By coupling the full-spectrum solar energy utilization system 6, the solar energy resources around the gas-steam combined cycle power plant can be fully utilized. Not only can the heat energy absorbed by the frequency-divided fluid in the vacuum collector tube 6-2 be transferred to the compressed air and feedwater through the air preheater 9 and feedwater preheater 12, but it can also generate electricity through the photovoltaic power generation panel 6-3, further improving the power generation capacity and efficiency of the power plant.

[0046] By using the high-temperature section of the frequency-divided fluid to heat the feedwater of the waste heat boiler 4 and the low-temperature section to heat the air, the synergistic optimization of the thermal system is achieved, which can maximize the utilization of thermal energy grade.

[0047] After passing through the frequency-distributed fluid circulation pump 19, the low-temperature frequency-distributed fluid first enters the frequency-distributed fluid preheater 18 for preheating, and then flows into the vacuum heat collection tube 6-2 to fully recover the waste heat of the system and improve the energy utilization efficiency of the system.

[0048] The frequency converter of the circulating pump can be used to control the flow rate of the sub-frequency fluid based on the real-time power load and solar radiation intensity, thereby optimizing the dynamic control strategy and achieving precise matching between power load, power generation and sub-frequency fluid flow rate.

[0049] This invention can perform peak shaving through the Ca(OH)2 / CaO system thermochemical energy storage system 7. The operating state (energy storage stage or energy release stage) of the Ca(OH)2 / CaO system thermochemical energy storage system 7 and the opening degree of valves A13, B14, C15, D16 and E17 can be adjusted according to the different power demand of the power plant to match the different power demand of the power plant.

[0050] This invention greatly increases the power plant's ability to quickly adjust load and its economic efficiency in deep peak shaving. It also has the ability to convert surplus electrical energy of the power plant, surrounding solar energy, and some waste heat from the gas turbines into high-grade thermal energy that can be stored for a long time and released quickly, thus significantly improving the overall flexibility, economy, and grid support of the power plant.

[0051] This invention can effectively recover the pressure energy that would otherwise be wasted in natural gas pressure reduction stations and convert it into electrical energy, thereby improving the power generation of power plants and the overall utilization efficiency of natural gas energy.

[0052] This invention utilizes full-spectrum solar energy utilization technology to preheat compressed air and feedwater of waste heat boiler 4, reducing the power consumption of compressor 3-1 by 10-15%, reducing the gas consumption of waste heat boiler 4, providing additional clean electricity, and increasing the comprehensive utilization rate of solar energy by more than 30%.

[0053] This invention uses the high-temperature section of the frequency-divided fluid to heat the feedwater of the waste heat boiler 4, and the low-temperature section to heat the air, thereby achieving synergistic optimization of the thermal system and maximizing the utilization of thermal energy grade.

[0054] In this invention, the low-temperature frequency-divided fluid first enters the frequency-divided fluid preheater 18 for preheating after passing through the frequency-divided fluid circulation pump 19, and then flows into the inlet of the vacuum heat collection tube 6-2 to fully recover the waste heat of the system and improve the energy utilization efficiency of the system.

[0055] This invention uses a circulating pump with variable frequency control to control the flow rate of a frequency-divided fluid based on real-time power load and solar radiation intensity, optimizing the dynamic control strategy to achieve precise matching between power load, power generation, and the flow rate of the frequency-divided fluid.

[0056] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0057] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0058] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A gas-steam combined cycle power generation system coupled with thermochemical energy storage, characterized in that, The system comprises a Ca(OH)2 / CaO thermochemical energy storage system (7), a high-pressure natural gas pipeline (1), a natural gas pressure differential power generation system (2), a gas turbine power generation system (3), a waste heat boiler (4), a frequency division fluid preheater (18), a steam turbine power generation system (5), a feedwater preheater (12), a valve A (13), a valve B (14), a valve C (15), an air preheater (9), and a valve D (16); the Ca(OH)2 / CaO thermochemical energy storage system (7) comprises a reactor body (7-1) and a steam drum (7-2); The high-pressure natural gas pipeline (1) is connected to the inlet of the gas turbine power generation system (3) through the natural gas pressure differential power generation system (2), and the outlet of the gas turbine power generation system (3) is connected to the outside environment through the heat-releasing side of the waste heat boiler (4) and the heat-releasing side of the frequency division fluid preheater (18). The outlet of the waste heat boiler (4) is divided into two paths after passing through the heat-absorbing side of the steam turbine power generation system (5) and the heat-absorbing side of the feedwater preheater (12), one path is connected to the tube side inlet of the reactor body (7-1) through the valve A (13), and the other path is connected to the heat-absorbing side inlet of the waste heat boiler (4) through the valve B (14); the tube side outlet of the reactor body (7-1) is connected to the heat-absorbing side inlet of the waste heat boiler (4) through the valve C (15). The outlet of the solar full-spectrum utilization system (6) is connected to the inlet of the solar full-spectrum utilization system (6) in sequence through the heat-releasing side of the feedwater preheater (12), the heat-releasing side of the air preheater (9), and the heat-releasing side of the frequency division fluid preheater (18); the outlet of the steam drum (7-2) is connected to the inlet of the steam drum (7-2) through the valve D (16), the shell side of the reactor shell, and the valve E (17).

2. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 1, wherein, The outlet of the solar full-spectrum utilization system (6) is connected to the inlet of the solar full-spectrum utilization system (6) in sequence through the heat-releasing side of the feedwater preheater (12), the heat-releasing side of the air preheater (9), the frequency division fluid circulating pump (19), and the heat-releasing side of the frequency division fluid preheater (18).

3. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 1, wherein, The outlet of the waste heat boiler (4) is divided into two paths in sequence after passing through the steam turbine power generation system (5), the condenser (10), the feedwater pump (11), and the heat-absorbing side of the feedwater preheater (12).

4. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 3, wherein, The gas turbine power generation system (3) comprises a compressor (3-1), a combustion chamber (3-2), a gas turbine (3-3), and a gas turbine generator (3-4); The high-pressure natural gas pipeline (1) is connected to the inlet of the combustion chamber (3-2) through the natural gas pressure differential power generation system (2); the outlet of the compressor (3-1) is connected to the inlet of the combustion chamber (3-2); the outlet of the combustion chamber (3-2) is connected to the inlet of the gas turbine (3-3); the outlet of the gas turbine (3-3) is connected to the outside environment in sequence through the heat-releasing side of the waste heat boiler (4) and the heat-releasing side of the frequency division fluid preheater (18).

5. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 4, wherein, The heat-absorbing side outlet of the air preheater (9) is connected to the inlet of the compressor (3-1).

6. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 1, wherein, The steam turbine power generation system (5) comprises a steam turbine (5-1) and a steam turbine generator (5-2), and the heat absorption side outlet of the waste heat boiler (4) is divided into two routes after passing through the heat absorption side of the steam turbine (5-1) and the feedwater preheater (12), and the steam turbine (5-1) is connected with the steam turbine generator (5-2).

7. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 1, wherein, The solar full spectrum utilization system (6) comprises a Fresnel lens (6-1), a vacuum heat collecting pipe (6-2) and a photovoltaic power generation panel (6-3), and the Fresnel lens (6-1), the vacuum heat collecting pipe (6-2) and the photovoltaic power generation panel (6-3) are sequentially arranged from top to bottom, and the vacuum heat collecting pipe (6-2) is connected with the heat absorption side outlet of the frequency separation fluid preheater (18) and the heat absorption side inlet of the feedwater preheater (12).

8. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 7, wherein, Among the solar radiation passing through the Fresnel lens (6-1), long-wave light is absorbed by the frequency separation fluid in the vacuum heat collecting pipe (6-2) and converted into heat energy, and the remaining short-wave light passes through the frequency separation fluid in the vacuum heat collecting pipe (6-2) and irradiates on the photovoltaic power generation panel (6-3) to perform photoelectric conversion.

9. The coupled thermochemical energy storage gas-steam combined cycle power generation system of claim 1, wherein, The valve A (13), the valve B (14), the valve C (15), the valve D (16) and the valve E (17) are all electrically adjusted valves.

10. A method of coupled thermochemical energy storage for a gas-steam combined cycle power generation, characterized in that, The gas-steam combined cycle power generation system coupled with thermochemical energy storage according to claim 1, comprising the following steps: The power generation capacities of the natural gas differential pressure power generation system (2), the gas turbine power generation system (3), the steam turbine power generation system (5) and the solar full spectrum utilization system (6) are respectively P1, P2, P3 and P4, and the maximum power generation capacity P of the system is P=P1+P2+P3+P4; The steam turbine power generation system (5) comprises a steam turbine (5-1) and a steam turbine generator (5-2), and the heat absorption side outlet of the waste heat boiler (4) is divided into two routes after passing through the heat absorption side of the steam turbine (5-1) and the feedwater preheater (12), and the steam turbine (5-1) is connected with the steam turbine generator (5-2). When P1+P2+P3< actual power consumption When P1+P2+P3< actual power consumption, the electric energy generated by the natural gas pressure differential power generation system (2), the gas turbine power generation system (3), the steam turbine power generation system (5) and the solar full spectrum utilization system (6) are all used for electric users. When the actual power consumption P4 is connected to the Ca(OH)2 / CaO thermo-chemical energy storage system (7), and the valve A (13), the valve C (15) and the valve D (16) are closed, the valve B (14) and the valve E (17) are opened, and the electric quantity P4 is converted into chemical energy and stored in the Ca(OH)2 / CaO thermo-chemical energy storage system (7). When the actual power consumption P1+P4 into the Ca(OH)2 / CaO system thermo-chemical energy storage system (7), and closes the valve A (13), the valve C (15) and the valve D (16), opens the valve B (14) and the valve E (17), and converts the electric energy P1+P4 into chemical energy and stores in the Ca(OH)2 / CaO system thermo-chemical energy storage system (7). When the actual power consumption <= P2, then the electric energy P1+P3+P4 generated by the natural gas pressure differential power generation system (2), the steam turbine power generation system (5) and the solar full spectrum utilization system (6) is connected to the Ca(OH)2 / CaO system thermochemical energy storage system (7), and the valve A (13), the valve C (15) and the valve D (16) are closed, the valve B (14) and the valve E (17) are opened, and the electric energy P1+P3+P4 is converted into chemical energy and stored in the Ca(OH)2 / CaO system thermochemical energy storage system (7). When the actual power consumption is less than the target power consumption, then open valve A (13), valve C (15) and valve D (16), close valve B (14) and valve E (17), the water vapor in the steam drum (7-2) is passed into the shell side of the reactor body (7-1) to react with CaO and release heat, the feed water flowing out of the feed water preheater (12) outlet first enters the tube side of the reactor body (7-1) through valve A (13) to absorb the chemical heat, and then enters the waste heat boiler (4) through valve C (15) to exchange heat, converting the chemical energy stored in the Ca(OH)2 / CaO system thermo-chemical energy storage system (7) into the heat energy of water vapor, at the same time, increasing the output of the feed water pump (11) to increase the steam flow and improve the power generation of the steam turbine power generation system (5).

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