A combined cycle power generation system coupling thermo-chemical heat storage and a gas turbine waste heat boiler

Abstract

The present application relates to the technical field of circulating power generation, and in particular to a combined cycle power generation system coupled with a thermal chemical heat storage and a gas turbine waste heat boiler, comprising: a gas turbine power generation system; a thermal chemical heat storage system, comprising a heat source unit and a heat storage unit; a waste heat boiler heat exchange system, comprising at least a flue gas side, a thermal chemical heat storage side and a steam-water side, the flue gas side being in communication with a flue gas outlet of the gas turbine power generation system; the thermal chemical heat storage side being in communication with a heat release output end of the thermal chemical heat storage system, and the steam-water side being used for inputting feed water and outputting steam, the waste heat boiler heat exchange system heating the feed water to generate steam by using heat input from the flue gas side and the thermal chemical heat storage side; and a steam turbine power generation system, comprising a steam inlet, the steam inlet being in communication with a steam-water side outlet of the waste heat boiler heat exchange system, and being used for generating power by using the steam to do work. The present application realizes efficient complementation and dynamic scheduling of multiple energies (solar heat, off-peak electricity and gas).

Description

Technical Field

[0001] This invention relates to the field of cycle power generation technology, specifically to a combined cycle power generation system that couples thermochemical thermal storage with a gas turbine waste heat boiler. Background Technology

[0002] With the development of clean energy and high-efficiency power generation technologies, gas-steam combined cycle power generation systems have become the mainstream power generation form in modern power systems due to their high thermal efficiency and rapid start-up and shutdown characteristics. However, traditional combined cycle systems still have significant shortcomings: when the system is under low load or rapid adjustment conditions, the steam output of the steam turbine is limited, and the steam turbine power generation load and the unit's heating capacity are directly determined by the gas turbine load. The overall operating cost fluctuates drastically with gas prices, making it difficult to balance economy and flexibility.

[0003] To address these issues, researchers have attempted to introduce renewable energy sources and energy storage units into combined cycle processes to alleviate fuel dependence and improve peak-shaving performance. Among these, solar thermal energy storage technology, which uses solar energy to heat a storage medium (such as molten salt) for thermal energy storage, has been widely applied in the field of solar thermal power generation. Such systems can store heat during the day and release it at night, providing an additional heat source for the steam loop. However, traditional molten salt thermal storage is sensible heat storage, with relatively low energy density and a narrow usable temperature range (typically not exceeding 590℃). Furthermore, molten salt suffers from heat loss, crystallization risk, and corrosion problems during long-term cycling. Especially when coupled with a gas-steam combined cycle system, the thermal efficiency and response speed of molten salt thermal storage are difficult to match the high-temperature dynamic characteristics of gas turbine exhaust, thus limiting the overall system efficiency and operational stability.

[0004] In recent years, thermochemical energy storage (TCES) technology has attracted widespread attention as a new generation of high-density energy storage. This technology achieves energy absorption and release through reversible chemical reactions, enabling stable operation in a relatively high temperature range (600~1200℃) and achieving long-term energy storage, near-zero heat loss, and controlled heat release. Compared to sensible heat storage, thermochemical energy storage offers advantages such as high energy density, high heat transfer efficiency, fast response speed, and compatibility with multi-energy systems. Especially in gas-steam combined cycle systems, introducing thermochemical reaction energy storage units to the waste heat boiler heat source side, allowing the heat absorption and release processes of the reaction to be coupled synergistically with the gas turbine exhaust, will significantly improve steam production and peak-shaving response capabilities.

[0005] However, there is currently a lack of an engineering solution that can deeply integrate thermochemical energy storage modules with gas-steam combined cycle systems. Existing research mostly focuses on independent thermal storage systems and has not fully considered the heat transfer matching between chemical reaction energy storage units and waste heat boilers, reaction kinetic control, and the synergistic mechanism between the heat release phase and turbine load regulation, resulting in low energy utilization efficiency. Summary of the Invention

[0006] The purpose of this invention is to provide a combined cycle power generation system that couples thermochemical thermal storage with a gas turbine waste heat boiler, thus solving the problems in the prior art.

[0007] This invention is achieved through the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide a combined cycle power generation system coupling thermochemical thermal storage and a gas turbine waste heat boiler, comprising:

[0009] Gas turbine power generation system, used to burn fuel to generate electricity and output high-temperature flue gas;

[0010] A thermochemical thermal energy storage system includes a heat source unit and a thermal energy storage unit; the heat source unit is used to provide thermal energy for the endothermic reaction of the thermal energy storage unit; the thermal energy storage unit is used to absorb and store thermal energy in the thermal energy storage stage through a reversible chemical reaction, and release thermal energy to the thermochemical thermal energy storage side of the waste heat boiler heat exchange system in the heat release stage.

[0011] The waste heat boiler heat exchange system includes at least a flue gas side, a thermochemical heat storage side, and a steam-water side. The flue gas side is connected to the flue gas outlet of the gas turbine power generation system for introducing the high-temperature flue gas. The thermochemical heat storage side is connected to the heat release output end of the thermochemical heat storage system for introducing the heat energy released by the thermochemical heat storage system. The steam-water side is used to introduce feedwater and output steam. The waste heat boiler heat exchange system uses the heat input from the flue gas side and the thermochemical heat storage side to heat the feedwater to generate steam.

[0012] A steam turbine power generation system includes a steam inlet connected to the steam-water side outlet of the waste heat boiler heat exchange system, for generating electricity by utilizing the steam.

[0013] Preferably, the gas turbine power generation system includes a gas turbine generator, a compressor, a combustion chamber, and a gas turbine section. The outlet of the compressor is connected to the inlet of the combustion chamber, the outlet of the combustion chamber is connected to the inlet of the gas turbine section, and the gas turbine section is coaxially connected to the gas turbine generator.

[0014] The waste heat boiler heat exchange system includes a waste heat boiler. The flue gas side of the waste heat boiler is connected to the exhaust port of the turbine section of the gas turbine. The steam-water side outlet of the waste heat boiler is connected to the steam inlet of the turbine unit of the steam turbine power generation system. The turbine unit is coaxially connected to the turbine generator. The exhaust port of the turbine unit is sequentially connected to a condenser, a feedwater pump, and a feedwater heater. The outlet of the feedwater heater is connected to the steam-water side inlet of the waste heat boiler, forming a closed steam-water cycle.

[0015] Preferably, the thermal storage unit includes a fixed-bed thermochemical reactor, a reaction gas control valve, and a reaction gas preheater;

[0016] The fixed-bed thermochemical reactor is filled with a thermochemical heat storage medium and adopts a partitioned heat exchange structure. The reaction zone is isolated from the heat carrier gas channel, and the partitioned heat exchange and reaction heat exchange are achieved through the heat carrier gas.

[0017] In the heat storage mode, the heat-carrying gas is heated by the heat source unit and then enters the heat-carrying gas channel of the fixed bed thermochemical reactor. Through heat transfer through the partition wall, the thermochemical heat storage medium undergoes an endothermic decomposition reaction, converting thermal energy into chemical energy for storage.

[0018] In the exothermic mode, the reaction gas is heated by the reaction gas preheater and then enters the reaction zone of the fixed-bed thermochemical reactor through the reaction gas control valve. It undergoes an exothermic reaction with the thermochemical heat storage medium, and the released chemical heat is transferred to the heat carrier gas channel through the partition wall. The heated heat carrier gas is then transported to the thermochemical heat storage side of the waste heat boiler.

[0019] Preferably, the heat source unit is a photothermal concentrating heat collection system or an electric heating system;

[0020] The solar thermal concentrating and collecting system includes a heliostat field, a solar thermal concentrating and collecting system, and a heat absorber. The heat absorber is located at the focal point of the solar thermal concentrating and collecting system and is used to focus solar radiation to heat the air. The outlet of the heat absorber is connected to the inlet of the heat-carrying gas channel of the fixed bed thermochemical reactor.

[0021] The electric heating system includes an input interface for off-peak or abandoned electricity from the power grid and an electric heating device. The inlet of the electric heating device is used to introduce air, and the outlet of the electric heating device is connected to the inlet of the heat transfer gas channel of the fixed bed thermochemical reactor.

[0022] Preferably, the thermal storage unit includes a high-temperature particle storage tank, a high-temperature side particle circulation pump, a low-temperature particle storage tank, and a low-temperature side particle circulation pump.

[0023] The outlet of the low-temperature particle storage tank is connected to the inlet of the low-temperature side particle circulation pump, and the outlet of the low-temperature side particle circulation pump is connected to the inlet of the high-temperature particle storage tank. The heat source unit is used to heat the particles between the outlet of the low-temperature side particle circulation pump and the channel of the high-temperature particle storage tank. The outlet of the high-temperature particle storage tank is connected to the inlet of the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler via the high-temperature side particle circulation pump. The outlet of the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler is connected to the inlet of the low-temperature particle storage tank, forming a closed solid particle circulation loop.

[0024] In the thermal storage mode, the low-temperature particles are transported to the high-temperature particle storage tank by the low-temperature side particle circulation pump. The heat source unit heats the particles before they enter the high-temperature particle storage tank, causing the particles to undergo an endothermic decomposition reaction, converting thermal energy into chemical energy for storage. The high-temperature particles after the reaction enter the high-temperature particle storage tank.

[0025] In exothermic mode, high-temperature particles are transported to the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler via the high-temperature side particle circulation pump. They come into contact with the reaction gas and undergo an exothermic reaction. The released chemical heat and particle sensible heat together heat the steam-water side of the waste heat boiler. The low-temperature particles after the reaction enter the low-temperature particle storage tank.

[0026] Preferably, the heat source unit is a photothermal concentrating heat collection system or an electric heating system;

[0027] The solar thermal concentrating system includes a heliostat field, a solar thermal concentrating system, and a particle heat absorber. The particle heat absorber is located between the low-temperature particle circulation pump and the high-temperature particle storage tank. The particle heat absorber is located at the focal point of the solar thermal concentrating system and is used to focus solar radiation to heat the particles in the particle heat absorber.

[0028] The electric heating system includes an input interface for off-peak or abandoned electricity from the power grid and an electric heating device. The electric heating device is located on the particle conveying channel between the low-temperature particle circulation pump and the high-temperature particle storage tank, or inside the high-temperature particle storage tank, and is used to heat the particles using electric energy during periods of low electricity prices.

[0029] Preferably, when the medium of the reversible chemical reaction is a carbonate system or a metal hydride system, the thermochemical thermal storage system further includes a reaction gas supply device, the outlet of which is connected to the inlet of the reaction gas preheater, for providing reaction gas corresponding to the medium of the reversible chemical reaction.

[0030] Preferably, the system further includes an intelligent control system, the intelligent control system comprising:

[0031] The status sensing module is used to collect system operating parameters, including grid load demand, load change rate, gas turbine exhaust temperature, steam pressure and steam flow rate of waste heat boiler, and bed temperature of fixed bed thermochemical reactor or granular absorber.

[0032] The principle priority decision module, connected to the state perception module, is used to generate control strategies based on safety constraint principles, steam supply stability principles, equipment life protection principles, operational economy principles, and low-carbon operation principles.

[0033] The operation mode management module, connected to the principle priority decision module, is used to output control signals to each actuator according to the generated control strategy, so as to realize the dynamic coordinated control of the gas turbine heat source and the thermochemical thermal storage heat source.

[0034] Preferably, the principle priority decision module is further used for:

[0035] Based on the preset safety constraint principles, it is determined whether the system meets the safe operation conditions. If the bed temperature of the fixed bed thermochemical reactor or the particle heat absorber exceeds the preset safety upper limit, the bed temperature difference exceeds the allowable range, the main steam pressure of the waste heat boiler exceeds the safety threshold, the heat exchange wall temperature of the waste heat boiler exceeds the allowable material temperature, the fluidization state of the fluidized bed is abnormal, or the concentration of the reactant gas is abnormal, a safety protection strategy is generated. The safety protection strategy is to reduce the thermochemical reaction rate or exit the heat release operation state and limit the gas turbine load change rate.

[0036] After meeting the safety constraints, the main steam pressure or temperature is judged to be deviated from the set value according to the steam supply stability principle. If a deviation occurs, a steam supply stability strategy is generated. The steam supply stability strategy is to restore the main steam parameters to the stable range by adjusting the thermochemical heat release power, the opening of the steam bypass valve, or the gas turbine load.

[0037] After meeting the requirements for stable steam supply, a life protection strategy is generated based on the equipment life protection principle. The life protection strategy is to limit the rate of change of bed temperature and the rate of change of thermochemical exothermic power of the fixed bed thermochemical reactor or the particle heat absorber in order to reduce thermal shock and material fatigue.

[0038] After meeting the equipment life protection requirements, an economic optimization strategy is generated based on the principle of operational economy. The economic optimization strategy is to optimize the allocation ratio of gas turbine output and thermochemical heat storage heat release power to minimize the comprehensive value of fuel consumption cost, unit start-up and shutdown loss and carbon emission cost.

[0039] Preferably, after meeting the economic optimization requirements, when there is a surplus of renewable energy or the risk of curtailment, a low-carbon operation strategy is generated by implementing the low-carbon operation principle. The low-carbon operation strategy is to drive a thermochemical endothermic reaction to achieve thermal storage operation.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] By introducing a thermochemical thermal energy storage system comprising a heat source unit and a thermal energy storage unit into a combined cycle system, and connecting the heat release output of the thermal energy storage unit to the thermochemical thermal energy storage side of the waste heat boiler, the chemical reaction heat released by the thermochemical thermal energy storage system and the flue gas from the gas turbine form a parallel heating structure within the waste heat boiler. In thermal energy storage mode, the system can utilize the heat energy provided by the gas turbine flue gas or the heat source unit to drive an endothermic reaction in the thermal energy storage medium, converting electrical energy or solar energy into chemical energy for storage. In heat release mode, the chemical heat released by the thermal energy storage unit and the gas turbine flue gas together heat the steam-water side of the waste heat boiler, enabling the steam turbine to obtain higher steam output and steam parameters under the same gas consumption conditions, thereby improving the overall power generation capacity and peak-shaving response speed of the combined cycle system.

[0042] By employing a coupled structure with gas turbine exhaust and thermochemical thermal storage as dual heat sources, the system can flexibly adjust the output ratio of the two heat sources when the grid load fluctuates. When the load increases, the stored heat is released first to supplement steam production; when the load decreases, excess energy is stored first. This reduces efficiency losses and thermal stress accumulation caused by frequent load changes in the gas turbine, extending the equipment's service life. Simultaneously, the thermochemical thermal storage system features high energy density, long storage period, and low heat loss, enabling stable operation in a high-temperature range of 600℃ to 1000℃. This effectively overcomes the shortcomings of traditional molten salt sensible heat storage, such as narrow temperature range and high heat loss, achieving efficient complementarity and dynamic scheduling of multiple energy sources (solar thermal, off-peak electricity, and gas). Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0044] Figure 1 Schematic diagram of the combined cycle power generation system coupled with thermochemical thermal storage and gas turbine waste heat boiler provided by the present invention Figure 1 ;

[0045] Figure 2 Schematic diagram of the combined cycle power generation system coupled with thermochemical thermal storage and gas turbine waste heat boiler provided by the present invention Figure 2 ;

[0046] Figure 3Schematic diagram of the combined cycle power generation system coupled with thermochemical thermal storage and gas turbine waste heat boiler provided by the present invention Figure 3 ;

[0047] Figure 4 Schematic diagram of the combined cycle power generation system coupled with thermochemical thermal storage and gas turbine waste heat boiler provided by the present invention Figure 4 ;

[0048] The attached diagram shows the markings and corresponding component names:

[0049] 1. Gas turbine generator; 2. Compressor; 3. Combustion chamber; 4. Gas turbine section; 5. Waste heat boiler; 6. Exhaust system and chimney; 7. Steam turbine unit; 8. Steam turbine generator; 9. Condenser; 10. Feedwater pump; 11. Feedwater heater; 12. Heliostat field; 13. Photothermal concentrating system; 14. Absorber; 15. Fixed-bed thermochemical reactor; 151. Reactant gas control valve; 16. Reactant gas preheater; 17. Reactant gas supply device; 18. Grid off-peak electricity or abandoned electricity input interface; 19. Electric heating device; 20. Particle absorber; 21. High-temperature particle storage tank; 22. High-temperature side particle circulation pump; 23. Low-temperature particle storage tank; 24. Low-temperature side particle circulation pump. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0052] It should be noted that all actions involving the acquisition of signals, information, or data in this invention are carried out in compliance with the relevant data protection laws and regulations of the locality and with authorization from the owner of the relevant device.

[0053] Example 1

[0054] Please see Figure 1 This invention provides a combined cycle power generation system coupling thermochemical thermal storage and a gas turbine waste heat boiler, comprising:

[0055] Gas turbine power generation system, used to burn fuel to generate electricity and output high-temperature flue gas;

[0056] A thermochemical thermal energy storage system includes a heat source unit and a thermal energy storage unit; the heat source unit is used to provide thermal energy for the endothermic reaction of the thermal energy storage unit; the thermal energy storage unit is used to absorb and store thermal energy in the thermal energy storage stage through a reversible chemical reaction, and release thermal energy to the thermochemical thermal energy storage side of the waste heat boiler heat exchange system in the heat release stage.

[0057] The waste heat boiler heat exchange system includes at least a flue gas side, a thermochemical heat storage side, and a steam-water side. The flue gas side is connected to the flue gas outlet of the gas turbine power generation system for introducing the high-temperature flue gas. The thermochemical heat storage side is connected to the heat release output end of the thermochemical heat storage system for introducing the heat energy released by the thermochemical heat storage system. The steam-water side is used to introduce feedwater and output steam. The waste heat boiler heat exchange system uses the heat input from the flue gas side and the thermochemical heat storage side to heat the feedwater to generate steam.

[0058] A steam turbine power generation system includes a steam inlet connected to the steam-water side outlet of the waste heat boiler heat exchange system, for generating electricity by utilizing the steam.

[0059] Specifically, the gas turbine power generation system is used to burn fuel to generate electricity and output high-temperature flue gas. This gas turbine power generation system can use a conventional gas turbine generator set. Air is drawn in and compressed by a compressor, and the compressed air is sent to the combustion chamber to mix and burn with gaseous fuels such as natural gas or hydrogen, generating high-temperature, high-pressure gas. The gas expands in the turbine, doing work to drive the generator to rotate, thereby converting the chemical energy of the fuel into electrical energy for output. The gas, still at a high temperature after performing its work, is discharged from the turbine exhaust port as high-temperature flue gas, serving as a heat source for subsequent waste heat recovery.

[0060] The thermochemical thermal storage system includes a heat source unit and a thermal storage unit. The heat source unit provides thermal energy for the endothermic reaction of the thermal storage unit and can employ a solar thermal collector based on concentrated solar power or an electric heating device utilizing off-peak electricity. The thermal storage unit absorbs and stores thermal energy during the storage phase through a reversible chemical reaction and releases the thermal energy to the thermochemical thermal storage side of the waste heat boiler heat exchange system during the exothermic phase. It can employ a fixed-bed reactor or a fluidized-bed reactor using metal oxides, carbonates, or metal hydrides as the reaction medium. In the storage mode, the high-temperature thermal energy provided by the heat source unit drives the thermal storage medium to undergo an endothermic decomposition reaction, converting thermal energy into chemical energy stored in the reaction products. In the exothermic mode, a gas matching the reaction system is introduced into the thermal storage unit, causing the thermal storage medium to undergo a reverse exothermic reaction, converting the stored chemical energy back into thermal energy for output.

[0061] The waste heat boiler heat exchange system includes at least a flue gas side, a thermochemical heat storage side, and a steam-water side. The flue gas side is connected to the flue gas outlet of the gas turbine power generation system to introduce the high-temperature flue gas. The thermochemical heat storage side is connected to the heat release output end of the thermochemical heat storage system to introduce the heat energy released by the thermochemical heat storage system. The steam-water side is used to introduce feedwater and output steam. The waste heat boiler heat exchange system uses the heat input from the flue gas side and the thermochemical heat storage side to heat the feedwater to generate steam. The waste heat boiler can adopt a three-channel heat exchange structure. The flue gas side receives the exhaust gas from the gas turbine and transfers the heat to the steam-water side. The thermochemical heat storage side receives the chemical reaction heat released by the heat storage unit in heat release mode and transfers the heat to the steam-water side. The two heat sources work in parallel inside the boiler to heat the feedwater and convert it into steam. The steam output from the steam-water side is then sent to the steam turbine power generation system to do work.

[0062] The steam turbine power generation system includes a steam inlet connected to the steam-water side outlet of the waste heat boiler heat exchange system, used to generate electricity by utilizing the steam. This steam turbine power generation system can employ a conventional steam turbine generator set. Steam enters the turbine through the main steam pipeline, expands and performs work in each stage of the turbine blades, converting the steam's thermal energy into the mechanical energy of the rotor rotation, driving the coaxially connected generator to output electrical energy. The exhaust steam, after completing its work, is cooled and condensed into water by the condenser, and then pressurized by the feedwater pump before returning to the steam-water side inlet of the waste heat boiler, forming a closed water-steam circulation loop.

[0063] In some implementation methods, reference is made to Figures 1 to 4The gas turbine power generation system includes a gas turbine generator 1, a compressor 2, a combustion chamber 3, and a gas turbine section 4. The outlet of the compressor 2 is connected to the inlet of the combustion chamber 3, and the outlet of the combustion chamber 3 is connected to the inlet of the gas turbine section 4. The gas turbine section 4 is coaxially connected to the gas turbine generator 1. The compressor compresses ambient air and sends it into the combustion chamber, where fuel and compressed air are mixed and burned to generate high-temperature, high-pressure gas. The gas drives the turbine section to rotate and perform work, which in turn drives the gas turbine generator to output electrical energy. The gas is discharged as high-temperature flue gas after the work is done. This gas turbine power generation system can use natural gas or hydrogen as fuel. The temperature of the high-temperature flue gas generated by combustion is typically maintained between 500°C and 650°C, providing a high-grade heat source for subsequent waste heat recovery.

[0064] In a combined cycle power generation system, the compressor continuously draws in ambient air and compresses it. The compressed air mixes and burns with fuel in the combustion chamber, producing high-temperature, high-pressure gas that drives the turbine blades to rotate. The turbine rotor then drives the generator to output electrical energy. The flue gas, after performing its work, still possesses a high thermodynamic energy level; direct emission would result in significant energy loss. By connecting the exhaust port of the gas turbine section to the flue gas side of a waste heat boiler, the high-temperature flue gas serves as one of the main heat sources for the waste heat boiler in subsequent heat exchange processes. After releasing heat within the waste heat boiler, the flue gas cools and is eventually discharged through the exhaust system. This arrangement allows the heat energy generated by fuel combustion to be partially converted into electrical energy in the gas turbine, while the remaining heat energy is recovered as flue gas by the waste heat boiler for secondary power generation, thus achieving the staged utilization of fuel heat energy.

[0065] In some implementation methods, reference is made to Figures 1 to 4 The waste heat boiler heat exchange system includes a waste heat boiler 5. The flue gas side of the waste heat boiler 5 is connected to the exhaust port of the turbine section 4 of the gas turbine. The steam-water side outlet of the waste heat boiler 5 is connected to the steam inlet of the turbine unit 7 of the steam turbine power generation system. The turbine unit 7 is coaxially connected to the turbine generator 8. The exhaust port of the turbine unit 7 is sequentially connected to the condenser 9, the feedwater pump 10, and the feedwater heater 11. The outlet of the feedwater heater 11 is connected to the steam-water side inlet of the waste heat boiler 5, forming a closed water-steam cycle. The waste heat boiler 5 receives the high-temperature flue gas discharged from the gas turbine on the flue gas side and transfers the heat to the steam-water side. After absorbing the heat, the steam-water side converts the feedwater into steam and sends it into the turbine unit. The flue gas is finally discharged through the exhaust system and chimney 6. After the steam expands and does work in the turbine unit to drive the turbine generator to generate electricity, the exhaust steam enters the condenser to cool and condense into water. After being pressurized by the feedwater pump, it is sent to the feedwater heater for preheating and then returned to the waste heat boiler for reheating, forming a cycle.

[0066] In a combined cycle power generation system, the waste heat boiler, as the core unit for heat energy integration and transfer, plays a crucial role in converting flue gas heat into steam power. Connected to the exhaust end of the gas turbine on the flue gas side, it receives high-temperature flue gas at approximately 500℃ to 650℃. Inside the boiler, the flue gas flows through heat exchangers, evaporators, and economizers, transferring heat to the feedwater on the steam-water side. This forms a closed water-steam cycle: feedwater, pressurized by a feedwater pump, is sent to the feedwater heater, where it is preheated using the waste heat from the flue gas at the tail end of the waste heat boiler. It then enters the evaporation section of the waste heat boiler to absorb heat and convert it into saturated steam. The saturated steam further absorbs heat in the superheating section, becoming high-temperature, high-pressure superheated steam, which is then sent to the turbine unit to perform work. The exhaust steam, after performing work, enters the condenser, exchanges heat with cooling water, and condenses into water. The condensate is then pressurized again by the feedwater pump and returned to the boiler, achieving recycling. The condenser can be water-cooled or air-cooled, and the feedwater heater can be a low-pressure heater or a high-pressure heater. Through this closed-loop structure, steam can return to the boiler for reheating after completing its work, realizing the recycling of the working fluid. At the same time, some of the waste heat from the flue gas is recovered through feedwater preheating, improving the overall thermal efficiency of the system.

[0067] In some implementation methods, reference is made to Figures 1 to 2 The thermal storage unit includes a fixed-bed thermochemical reactor 15, a reaction gas control valve 151, and a reaction gas preheater 16. The fixed-bed thermochemical reactor 15 is filled with a thermochemical thermal storage medium and employs a partitioned heat exchange structure. The reaction zone is isolated from the heat transfer gas channel, and the partitioned heat exchange and reaction heat exchange are achieved through the heat transfer gas. The thermochemical thermal storage medium can be a substance capable of reversible endothermic or exothermic reactions at high temperatures, such as metal oxides, carbonates, or metal hydrides. The heat transfer gas can be a heat-conducting medium such as air or nitrogen. The reaction gas control valve 151 is used to regulate the flow rate and on / off state of the reaction gas, and the reaction gas preheater 16 is used to heat the reaction gas to a set temperature before sending it into the reaction zone.

[0068] In thermal storage mode, the heat-carrying gas, heated by the heat source unit, enters the heat-carrying gas channel of the fixed-bed thermochemical reactor 15. Heat transfer through the indirect wall causes the thermochemical storage medium to undergo an endothermic decomposition reaction, converting thermal energy into chemical energy for storage. When the system is under low load or when renewable energy is abundant, the heat source unit, such as a solar thermal concentrator or electric heating system, heats the heat-carrying gas to a high temperature of 600°C to 1000°C. As the high-temperature heat-carrying gas flows through the heat-carrying gas channel of the fixed-bed reactor, heat is transferred through the reactor wall to the reaction zone, driving the thermochemical storage medium to undergo a decomposition reaction. For example, when using a metal oxide system, high-valence oxides absorb heat and decompose into low-valence oxides, releasing oxygen; when using a carbonate system, carbonates decompose into metal oxides and carbon dioxide. The reaction products are stored inside the reactor or in independent storage tanks, converting thermal energy into chemical energy for storage, achieving long-term near-zero heat loss energy storage.

[0069] In exothermic mode, the reactant gas, after being heated by the reactant gas preheater 16, enters the reaction zone of the fixed-bed thermochemical reactor 15 via the reactant gas control valve 151. It undergoes an exothermic reaction with the thermochemical heat storage medium, and the released chemical heat is transferred through the partition wall to the heat carrier gas channel. The heated heat carrier gas is then transported to the thermochemical heat storage side of the waste heat boiler 5. When the grid load increases or power generation is required, the control system opens the reactant gas control valve and selects the appropriate reactant gas according to the type of heat storage medium used (e.g., air for metal oxide systems, carbon dioxide for carbonate systems, and hydrogen for metal hydride systems). The reactant gas, after being heated to an appropriate temperature by the preheater, enters the reaction zone and undergoes a reverse chemical reaction with the heat storage medium, converting the stored chemical energy into released heat energy. The released heat is transferred through the partition wall to the heat carrier gas channel, heating the heat carrier gas to a high temperature before it is sent to the thermochemical heat storage side of the waste heat boiler. This heat, combined with the gas turbine exhaust, heats the steam and water side, thereby increasing steam production and turbine output without increasing fuel consumption.

[0070] This indirect-bed structure allows for heat transfer between the thermal storage unit and the waste heat boiler via a heat transfer gas loop. The isolation between the reaction zone and the heat transfer gas channel prevents direct contact between the reaction medium and the heat transfer gas, ensuring independent control of the reaction atmosphere and avoiding contamination of the heat exchange walls by reaction products. In thermal storage mode, the reactor stores thermal energy in the form of chemical energy, with an energy density higher than sensible thermal storage, and the storage period is not limited by time. In exothermic mode, the exothermic power can be flexibly controlled by adjusting the flow rate and temperature of the reaction gas, enabling rapid response to steam parameters.

[0071] In some implementation methods, reference is made to Figure 1The heat source unit can be a solar thermal concentrating system. The solar thermal concentrating system includes a heliostat field 12, a solar thermal concentrating system 13, and a receiver 14. The receiver 14 is located at the focal point of the solar thermal concentrating system 13 and is used to focus solar radiation to heat the air. The outlet of the receiver 14 is connected to the inlet of the heat-carrying gas channel of the fixed-bed thermochemical reactor 15. The heliostat field consists of multiple sun-tracking mirrors that reflect and converge solar radiation to the solar thermal concentrating system. The solar thermal concentrating system further focuses the light onto the receiver, heating the air inside the receiver to a high temperature.

[0072] When solar thermal resources are abundant and the system is in thermal storage mode, the heliostat tracks the sun's position and reflects incident sunlight to the solar thermal concentrating system. After secondary focusing, a high-energy flux density light spot is formed at the focal point of the receiver. Air is used as the heat transfer medium inside the receiver; as it flows through, it absorbs the focused light energy, raising its temperature to over 600°C. This high-temperature air is then piped into the heat transfer gas channel of the fixed-bed thermochemical reactor. Through heat transfer via the insulator walls, it drives the thermochemical thermal storage medium within the reactor to undergo an endothermic decomposition reaction, converting solar energy into stored chemical energy. This solar thermal collection method converts unstable solar radiation into a stable and controllable high-temperature heat input, providing a clean heat source for the thermochemical thermal storage system. When there is insufficient sunlight at night or on cloudy or rainy days, the system can switch to gas turbine exhaust heating or electric heating to supplement heat, achieving multi-energy complementary operation.

[0073] refer to Figure 2 The heat source unit can be an electric heating system. The electric heating system includes a grid off-peak electricity or abandoned electricity input interface 18 and an electric heating device 19. The inlet of the electric heating device 19 is used to introduce air, and the outlet of the electric heating device 19 is connected to the inlet of the heat-carrying gas channel of the fixed-bed thermochemical reactor 15. The grid off-peak electricity or abandoned electricity input interface is used to connect to electricity generated during off-peak hours or abandoned renewable energy, and the electric heating device is used to convert electrical energy into heat energy to heat the air.

[0074] During periods of low electricity load or when power curtailment occurs, the system connects to low-priced electricity through the grid's off-peak or curtailment input interface, activating the electric heating device. The electric heating device can employ resistance heating, electromagnetic induction heating, or electrode heating to heat the air flowing through it to the required temperature. This high-temperature air is then piped into the heat-carrying gas channel of the fixed-bed thermochemical reactor. Through heat transfer via the indirect walls, it drives the thermochemical storage medium within the reactor to undergo an endothermic decomposition reaction, converting electrical energy into stored chemical energy. This electric heating method allows the system to store energy at night or during periods of low electricity prices, and release heat during the day or during periods of high electricity prices to drive a steam turbine for power generation, achieving peak shaving and valley filling. Electromagnetic induction heating provides rapid response and precise temperature control; resistance heating offers a simpler structure and lower cost. By configuring different types of electric heating devices, the system can flexibly adjust the thermal storage power based on grid price signals and power curtailment, improving the economics of energy utilization and the grid's ability to absorb renewable energy.

[0075] In some implementation methods, reference is made to Figures 3 to 4 The heat storage unit includes a high-temperature particle storage tank 21, a high-temperature side particle circulation pump 22, a low-temperature particle storage tank 23, and a low-temperature side particle circulation pump 24. The outlet of the low-temperature particle storage tank 23 is connected to the inlet of the low-temperature side particle circulation pump 24, and the outlet of the low-temperature side particle circulation pump 24 is connected to the inlet of the high-temperature particle storage tank 21. The heat source unit is used to heat the particles between the outlet of the low-temperature side particle circulation pump 24 and the channel of the high-temperature particle storage tank 21. The outlet of the high-temperature particle storage tank 21 is connected to the inlet of the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler 5 via the high-temperature side particle circulation pump 22, and the outlet of the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler 5 is connected to the inlet of the low-temperature particle storage tank 23, forming a closed solid particle circulation loop. The high-temperature side particle circulation pump and the low-temperature side particle circulation pump can be equipped with mechanical conveying devices or pneumatic conveying devices to drive the particles to circulate in the loop.

[0076] In thermal storage mode, low-temperature particles are transported to the high-temperature particle storage tank 21 via the low-temperature side particle circulation pump 24. The heat source unit heats the particles before they enter the high-temperature particle storage tank 21, causing them to undergo an endothermic decomposition reaction, converting thermal energy into chemical energy for storage. The high-temperature particles after the reaction then enter the high-temperature particle storage tank 21. When the system is under low load or when renewable energy is abundant, the heat source unit, such as a solar thermal concentrating collector system or an electric heating system, provides high-temperature thermal energy. The solid particles before entering the high-temperature particle storage tank 21 form a fluidized bed under the action of fluidizing gas. The particles are uniformly heated within the bed and undergo an endothermic decomposition reaction, converting thermal energy into chemical energy stored inside the particles. For example, when metal oxide particles are used, the particles decompose into low-valence oxides at high temperatures and release oxygen; when carbonate particles are used, the particles decompose into metal oxides and release carbon dioxide. The high-temperature particles that have completed the endothermic reaction enter the high-temperature particle storage tank for storage via a conveying pipeline. An insulation layer is installed on the outside of the high-temperature particle storage tank to reduce heat loss during storage.

[0077] In exothermic mode, high-temperature particles are transported by the high-temperature side particle circulation pump 22 to the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler 5. There, they come into contact with the reacting gas and undergo an exothermic reaction. The released chemical heat, along with the sensible heat of the particles, heats the steam-water side of the waste heat boiler 5. The resulting low-temperature particles then enter the low-temperature particle storage tank 23. When the grid load increases or additional power generation is required, the high-temperature side particle circulation pump continuously feeds high-temperature particles from the high-temperature particle storage tank into the gas-solid reaction heat exchange chamber. This chamber is located at the front end of the waste heat boiler and contains heat exchange walls and heated surface tube bundles. Depending on the selected particle type, a corresponding reacting gas is introduced into the chamber (e.g., air for metal oxide systems, carbon dioxide for carbonate systems, and hydrogen for metal hydride systems). The high-temperature particles react with the reacting gas in a reverse exothermic reaction, converting the stored chemical energy into released heat energy. The chemical heat released by the reaction, along with the sensible heat carried by the particles themselves, is transferred through the heat exchange walls to the steam-water side of the waste heat boiler, heating the feedwater to generate steam. After the exothermic reaction is completed, the temperature of the particles decreases. They are collected by a separation device and enter a low-temperature particle storage tank, waiting for the next heat storage cycle.

[0078] Through this fluidized bed closed-loop particle circulation structure, the thermal storage unit achieves continuous circulation and transport of the thermal storage medium between the thermal storage and heat release stages. The particle absorber is coupled to the heat source unit, which can heat the particles to the reaction temperature and complete the heat absorption and energy storage under photothermal or electric heating conditions; the gas-solid reaction heat exchange chamber is coupled to the waste heat boiler, which can simultaneously transfer chemical heat and sensible heat to the steam-water side during heat release. During the circulation process, the particles act as both a chemical reaction carrier storing chemical energy and a sensible heat carrier carrying heat, realizing the synergistic utilization of chemical energy and thermal energy. The fluidized bed structure enables the particles to form a uniform fluidization state in both the absorber and the reaction chamber, resulting in high heat transfer efficiency and fast reaction rate, making it suitable for peak-shaving scenarios requiring rapid response and high power output.

[0079] In some implementation methods, reference is made to Figure 3 The heat source unit can be a solar thermal concentrating solar collector system. The solar thermal concentrating solar collector system includes a heliostat field 12, a solar thermal concentrating solar collector system 13, and a particle heat absorber 20. The particle heat absorber 20 is located between the low-temperature particle circulation pump 24 and the high-temperature particle storage tank 21. The particle heat absorber 20 is located at the focal point of the solar thermal concentrating solar collector system 13, used to focus solar radiation to heat the particles inside the particle heat absorber 20. The heliostat field consists of multiple sun-tracking mirrors that reflect and converge solar radiation to the solar thermal concentrating solar collector system. The solar thermal concentrating solar collector system further focuses the light onto the particle heat absorber, heating the solid particles inside the particle heat absorber to a high temperature. The particle heat absorber can adopt an open-top or closed tube sheet structure, with an internal fluidizing distributor and wear-resistant lining to achieve uniform fluidization of the particles and efficient heat absorption.

[0080] When solar thermal resources are abundant and the system is in thermal storage mode, heliostats track the sun's position and reflect incident sunlight to the solar thermal concentrating system. After secondary focusing, a high-energy flux density light spot is formed within the particle receiver. The particle receiver can adopt an open-top or closed tube-plate structure, with an internal fluidized bed distributor. Solid particles form a fluidized bed under the action of fluidizing gas. During the circulation of the particles within the bed, they absorb the focused light energy, raising their temperature to over 600℃ and undergoing an endothermic decomposition reaction, converting solar energy into chemical energy stored inside the particles. The high-temperature particles that have completed the endothermic reaction are then transported through pipelines to a high-temperature particle storage tank for storage. This solar thermal collection method converts unstable solar radiation into stable and controllable high-temperature heat energy input, providing a clean heat source for the thermochemical thermal storage system. When there is insufficient sunlight at night or on cloudy or rainy days, the system can switch to gas turbine exhaust heating or electric heating to supplement heat, achieving multi-energy complementary operation.

[0081] refer to Figure 4The heat source unit can employ an electric heating system. The electric heating system includes a grid off-peak electricity or abandoned electricity input interface 18 and an electric heating device 19. The electric heating device 19 is located on the particle conveying channel between the low-temperature particle circulation pump 24 and the high-temperature particle storage tank 21, or inside the high-temperature particle storage tank 21, and is used to heat the particles using electrical energy during periods of low electricity prices. The grid off-peak electricity or abandoned electricity input interface is used to connect to off-peak electricity or abandoned renewable energy, and the electric heating device is used to convert electrical energy into heat energy to directly heat the particles.

[0082] During periods of low electricity load or when power curtailment occurs, the system connects to low-cost electricity through the grid's off-peak or curtailed power input interface, and the electric heating device starts operating. When the electric heating device is installed on the particle conveying channel, the low-temperature particles flow through the heating zone during transport from the low-temperature particle storage tank to the high-temperature particle storage tank, absorbing the heat released by the electric heating device and heating up. When the electric heating device is installed inside the high-temperature particle storage tank, the particles directly absorb the heat released by the electric heating device during their fluidized movement within the tank. The electric heating device can employ resistance heating, electromagnetic induction heating, or electrode heating to achieve rapid heating of the particles. After heating, the particles undergo an endothermic decomposition reaction inside the high-temperature particle storage tank, converting electrical energy into chemical energy for storage. This electric heating method allows the system to store energy at night or during periods of low electricity prices, and release heat during the day or during periods of high electricity prices to drive a steam turbine for power generation, achieving peak shaving and valley filling of electricity. When the electric heating device is installed on the particle conveying channel, continuous heating of the particles can be achieved, suitable for high-flow-rate conditions; when installed inside the high-temperature particle storage tank, the heating area is concentrated, resulting in higher thermal efficiency. By configuring different types of electric heating devices, the system can flexibly adjust the thermal storage power according to the grid electricity price signal and the situation of power curtailment, thereby improving the economic efficiency of energy utilization.

[0083] In some implementation methods, reference is made to Figures 1 to 4 When the medium for the reversible chemical reaction is a carbonate system or a metal hydride system, the thermochemical thermal storage system further includes a reaction gas supply device 17. The outlet of the reaction gas supply device 17 is connected to the inlet of the reaction gas preheater 16, and is used to provide the reaction gas corresponding to the medium for the reversible chemical reaction. The reaction gas supply device may include a gas storage tank, a booster compressor, a flow regulating valve, and a recovery unit. The gas storage tank is used to store carbon dioxide or hydrogen, the booster compressor is used to boost the gas to the required pressure, the flow regulating valve is used to control the gas flow rate, and the recovery unit is used to collect and recycle unreacted gas.

[0084] When using a carbonate system, the reaction gas supply device provides carbon dioxide gas. In thermal storage mode, the carbonate medium decomposes into metal oxides at high temperatures, releasing carbon dioxide. The released carbon dioxide can be collected, cooled, compressed, and stored in a gas storage tank by a recovery unit, achieving gas recycling. In exothermic mode, the reaction gas supply device pressurizes the stored carbon dioxide using a booster compressor and sends it to the reaction gas preheater. After being heated to the set temperature, it enters the reaction zone, where it undergoes a carbonation reaction with the metal oxides, releasing heat. The supply pressure and flow rate of carbon dioxide directly affect the reaction rate and exothermic power; precise control of the exothermic power can be achieved through a flow regulating valve.

[0085] When using a metal hydride system, the reaction gas supply unit provides hydrogen. In thermal storage mode, the metal hydride decomposes into metal at high temperature, releasing hydrogen. The released hydrogen is collected and purified by a recovery unit and stored in a high-safety-level hydrogen storage device. In exothermic mode, the reaction gas supply unit pressurizes the stored hydrogen using a booster compressor and sends it to the reaction gas preheater. After being heated to a set temperature, it enters the reaction zone, where it undergoes a hydrogenation reaction with the metal, releasing heat. Due to the flammable and explosive properties of hydrogen, the reaction gas supply unit must be equipped with explosion-proof valves, an online hydrogen concentration monitor, and an inert gas replacement module to ensure safe operation in a high-temperature hydrogen environment.

[0086] Compared to metal oxide systems, which can directly utilize oxygen from the air as the reactant gas, carbonate and metal hydride systems require independent reactant gas supply devices to provide carbon dioxide or hydrogen. By configuring a gas storage tank, a booster compressor, and a recovery unit, the reactant gas supply device can achieve closed-loop recycling of the reactant gas, reducing gas consumption and emissions. In exothermic mode, the exothermic rate can be dynamically controlled by adjusting the pressure and flow rate of the reactant gas, thereby matching the heat demand of turbine load changes. After the system has been running for a long time, the reactant gas can be purified and replenished through the recovery unit to maintain a stable reaction atmosphere and ensure the cyclic stability and service life of the thermochemical thermal storage system.

[0087] In some embodiments, the system further includes an intelligent control system, which includes:

[0088] The status sensing module is used to collect system operating parameters, including grid load demand, load change rate, gas turbine exhaust temperature, steam pressure and flow rate of waste heat boiler 5, and bed temperature of fixed-bed thermochemical reactor 15 or granular absorber 20. The status sensing module can be implemented using a combination of a distributed sensor network and a data acquisition system. Grid load demand and load change rate can be obtained through a power measurement device at the grid connection interface; gas turbine exhaust temperature can be measured at the exhaust pipe using thermocouples or infrared thermometers; steam pressure and flow rate of the waste heat boiler can be measured at the steam-water side outlet pipe using pressure transmitters and flow meters; and bed temperature can be achieved using a multi-point thermocouple array arranged at different heights inside the reactor. The analog signals collected by each sensor are converted from analog to digital and then sent to the controller for unified processing.

[0089] During system operation, the status sensing module continuously collects the above parameters at a set sampling frequency, forming a real-time operating status dataset. Grid load demand reflects the current power generation tasks the system needs to undertake, while the load change rate characterizes the grid's requirement for the unit's regulation speed. Gas turbine exhaust temperature is a direct indicator of the quality of the heat source on the flue gas side, determining the basic heat load capacity of the waste heat boiler. Steam pressure and steam flow rate are key operating parameters on the turbine side, reflecting the degree of deviation between the current steam output and the set value. The bed temperature of the fixed-bed thermochemical reactor or granular absorber is an important indicator of the chemical reaction process within the heat storage unit; the uniformity of bed temperature distribution directly affects the reaction rate and heat storage / release efficiency. By aggregating these multi-dimensional parameters into the control system, complete operating status information is provided to the subsequent decision-making module.

[0090] The principle priority decision-making module, connected to the state perception module, is used to generate control strategies based on safety constraint principles, steam supply stability principles, equipment life protection principles, operational economy principles, and low-carbon operation principles. The principle priority decision-making module can be implemented using an embedded controller or an industrial computer, and internally has preset judgment logic and priority order for each principle.

[0091] Safety constraints are prioritized to ensure system operational safety. When the status sensing module detects that the bed temperature exceeds the preset safety limit, the bed temperature difference exceeds the allowable range, the main steam pressure of the waste heat boiler exceeds the safety threshold, the boiler heat exchanger wall temperature exceeds the material's allowable temperature, or the fluidized bed fluidization state or reactant gas concentration is abnormal, the priority decision module immediately generates a safety protection strategy. This strategy reduces the thermochemical reaction rate or exits the heat release operation state, and limits the gas turbine load change rate. After meeting the safety constraints, the decision module determines whether the main steam pressure or temperature deviates from the set value based on the steam supply stability principle. If a deviation occurs, a steam supply stabilization strategy is generated, adjusting the thermochemical heat release power, steam bypass valve opening, or gas turbine load to restore the main steam parameters to a stable range. After meeting the steam supply stabilization requirements, the decision module generates a lifespan protection strategy based on the equipment lifespan protection principle, limiting the bed temperature change rate and the thermochemical heat release power change rate to reduce thermal shock and material fatigue. After meeting equipment lifespan protection requirements, the decision-making module generates an economic optimization strategy based on the principle of operational economy. This strategy optimizes the allocation of the ratio between gas turbine output and thermochemical thermal storage heat release power, minimizing the combined cost of fuel consumption, unit start-up and shutdown losses, and carbon emission costs. When there is a surplus of renewable energy or a risk of curtailment, the decision-making module prioritizes low-carbon operation principles, generating a low-carbon operation strategy to drive the thermochemical endothermic reaction for thermal storage operation. Through a five-level principle-based hierarchical judgment, the decision-making module can generate a comprehensive control strategy that balances safety, stability, lifespan, economy, and low carbon emissions under different operating conditions.

[0092] The operation mode management module, connected to the principle priority decision module, is used to output control signals to each actuator according to the generated control strategy, thereby realizing dynamic coordinated control of the gas turbine heat source and the thermochemical thermal storage heat source. The operation mode management module can be implemented using a programmable logic controller or a distributed control system, and has pre-set execution schemes corresponding to each control strategy.

[0093] When a safety protection strategy is received, the operation mode management module outputs a signal to the reactant gas control valve to reduce or close it, thereby lowering the thermochemical reaction rate or exiting the heat release operation state. Simultaneously, it outputs a load change rate limit signal to the gas turbine control system to prevent excessive thermal shock to the equipment. When a steam supply stabilization strategy is received, the operation mode management module, based on the direction and magnitude of the main steam parameter deviation, outputs a flow rate adjustment signal to the reactant gas supply device of the thermochemical thermal storage system to adjust the heat release power, or outputs an opening adjustment signal to the steam bypass valve to bypass part of the steam, or outputs a load adjustment signal to the gas turbine control system to bring the main steam parameters back to the set value. When a lifespan protection strategy is received, the operation mode management module outputs a change rate limit signal to the reactant gas control valve to prevent sudden changes in heat release power from causing drastic fluctuations in bed temperature. When an economic optimization strategy or a low-carbon operation strategy is received, the operation mode management module, based on the target output ratio calculated through optimization, outputs a load setpoint to the gas turbine control system, and simultaneously outputs flow rate and speed setpoints to the reactant gas supply device and circulating pump of the thermochemical thermal storage system to achieve coordinated distribution of the output from the two heat sources. Through the coordinated actions of various actuators, the operation mode management module transforms the control strategies generated by the decision-making module into specific physical actions, enabling the system to maintain dynamic coordination between the gas turbine heat source and the thermochemical thermal storage heat source under different operating conditions.

[0094] In some implementations, the principle priority decision module is further used for:

[0095] Based on the preset safety constraint principles, it is determined whether the system meets the safe operation conditions. If the bed temperature of the fixed bed thermochemical reactor 15 or the granular heat absorber 20 exceeds the preset safety upper limit, the bed temperature difference exceeds the allowable range, the main steam pressure of the waste heat boiler 5 exceeds the safety threshold, the heat exchange wall temperature of the waste heat boiler 5 exceeds the material allowable temperature, the fluidization state of the fluidized bed is abnormal, or the concentration of the reacting gas is abnormal, a safety protection strategy is generated. The safety protection strategy is to reduce the thermochemical reaction rate or exit the heat release operation state and limit the gas turbine load change rate.

[0096] After meeting the safety constraints, the main steam pressure or temperature is judged to be deviated from the set value according to the steam supply stability principle. If a deviation occurs, a steam supply stability strategy is generated. The steam supply stability strategy is to restore the main steam parameters to the stable range by adjusting the thermochemical heat release power, the opening of the steam bypass valve, or the gas turbine load.

[0097] After meeting the requirements for stable steam supply, a life protection strategy is generated according to the equipment life protection principle. The life protection strategy is to limit the rate of change of bed temperature and the rate of change of thermochemical heat release power of the fixed bed thermochemical reactor 15 or the particle heat absorber 20 in order to reduce thermal shock and material fatigue.

[0098] After meeting the equipment life protection requirements, an economic optimization strategy is generated based on the principle of operational economy. The economic optimization strategy is to optimize the allocation ratio of gas turbine output and thermochemical heat storage heat release power to minimize the comprehensive value of fuel consumption cost, unit start-up and shutdown loss and carbon emission cost.

[0099] Specifically, the principle priority decision module determines whether the system meets safe operating conditions based on preset safety constraint principles. If the bed temperature of the fixed-bed thermochemical reactor 15 or the granular heat absorber 20 exceeds the preset safety upper limit, the bed temperature difference exceeds the allowable range, the main steam pressure of the waste heat boiler 5 exceeds the safety threshold, the heat exchange wall temperature of the waste heat boiler 5 exceeds the material's allowable temperature, the fluidized bed fluidization state is abnormal, or the reactant gas concentration is abnormal, a safety protection strategy is generated. The safety protection strategy is to reduce the thermochemical reaction rate or exit the heat release operation state, and limit the gas turbine load change rate. The safety constraint principle serves as the highest priority decision basis to ensure the safety of equipment and personnel during system operation.

[0100] During system operation, if the bed temperature of a fixed-bed thermochemical reactor or granular absorber exceeds the preset safety limit, it may lead to sintering of the reaction medium or damage to the reactor structure. A bed temperature difference exceeding the allowable range indicates uneven temperature distribution within the reaction zone, posing a risk of localized overheating. When the main steam pressure of the waste heat boiler exceeds the safety threshold, it may trigger overpressure protection of the pressure vessel. If the heat exchanger wall temperature exceeds the material's allowable temperature, it may cause pipe creep or cracking. Abnormal fluidization state of the fluidized bed manifests as fluctuations in bed pressure drop or particle blockage; abnormal reactant gas concentration may trigger combustion or explosion risks. The principle priority decision module monitors the above parameters in real time. When any parameter exceeds the safety boundary, it immediately interrupts the normal scheduling logic and generates a safety protection strategy. This strategy prioritizes reducing the thermochemical reaction rate or causing the system to exit the heat release operation state, while simultaneously outputting a load change rate limit signal to the gas turbine control system to avoid thermal shock caused by rapid load changes, ensuring the system operates within the safety boundary.

[0101] After meeting safety constraints, the principle priority decision module determines whether the main steam pressure or temperature deviates from the set value according to the steam supply stability principle. If a deviation occurs, a steam supply stability strategy is generated. This strategy involves adjusting the thermochemical heat release power, the steam bypass valve opening, or the gas turbine load to restore the main steam parameters to a stable range. The steam supply stability principle is used to ensure the stability of steam quality on the turbine side and avoid affecting power generation efficiency and equipment lifespan due to fluctuations in steam parameters.

[0102] When the main steam pressure is lower than the set value, it indicates that the steam output is insufficient to meet the turbine's demand. The priority decision module will prioritize increasing the thermochemical heat release power by increasing the reaction gas flow rate or particle circulation volume to allow the thermal storage unit to release more heat and supplement the steam-side heat load. If the main steam pressure is higher than the set value, the thermochemical heat release power will be reduced or some steam will be diverted through a steam bypass valve. When the main steam temperature deviates from the set value, the heat distribution entering the waste heat boiler can be changed by adjusting the reaction heat flux, or the steam temperature can be adjusted by using desuperheating water. If the thermochemical thermal storage system's adjustment capability is insufficient to eliminate steam parameter deviations, the gas turbine load will be adjusted to change the heat of the flue gas entering the waste heat boiler. Through coordinated adjustment using multiple methods, the main steam pressure, temperature, and flow rate will operate within the allowable fluctuation range, ensuring stable power generation by the turbine unit.

[0103] After meeting the steam supply stability requirements, the principle priority decision module generates a lifespan protection strategy based on the equipment lifespan protection principle. This strategy limits the rate of change of bed temperature and the rate of change of thermochemical heat release power in the fixed-bed thermochemical reactor 15 or the granular heat absorber 20 to reduce thermal shock and material fatigue. The equipment lifespan protection principle is used to extend the service life of key equipment in the thermochemical thermal storage system and waste heat boiler.

[0104] During system operation, rapid changes in bed temperature can generate thermal stress inside the reactor, and frequent temperature fluctuations may lead to cracking of the reaction medium or fatigue damage to the reactor wall. The principle priority decision module sets an upper limit on the rate of bed temperature change. When the rate of temperature change exceeds the set threshold, it limits the rate of change of the reactant gas flow rate or particle circulation volume to ensure a smoother change in bed temperature. Similarly, sudden changes in thermochemical exothermic power can subject the waste heat boiler heat exchanger wall to alternating heat loads, accelerating material fatigue. The lifespan protection strategy limits the rate of change of exothermic power to ensure a smooth transition in heat input. For fluidized bed structures, excessive particle erosion of the wall is prevented by adjusting the fluidizing gas velocity. Through these limiting measures, the accumulation of thermal stress under frequent peak-shaving conditions is reduced, extending the service life of the reactor and heat exchange equipment.

[0105] After meeting the equipment lifespan protection requirements, the principle priority decision module generates an economic optimization strategy based on the principle of operational economy. This strategy optimizes the allocation of the ratio between gas turbine output and thermochemical thermal storage heat release power to minimize the combined cost of fuel consumption, unit start-up and shutdown losses, and carbon emission costs. The principle of operational economy aims to minimize system operating costs while meeting safety and stability constraints.

[0106] The principle-priority decision-making module establishes a comprehensive cost function based on current gas prices, the thermal storage status of the thermal storage system, grid load demand, and carbon emission allowance prices. Fuel consumption costs are positively correlated with gas turbine output. When gas prices are high, the thermal storage system is prioritized to release heat to bear the heat load, reducing gas consumption. Unit start-up and shutdown losses include efficiency decline and increased maintenance costs caused by frequent load changes in the gas turbine. When the load change rate is large, the thermal storage unit is prioritized to bear transient heat compensation, keeping the gas turbine in a high-efficiency and stable load range. Carbon emission costs are related to fuel consumption and carbon emission factors. When there is a surplus of renewable energy, thermal storage operation is prioritized to absorb low-carbon energy and reduce overall carbon emissions. The decision-making module calculates the optimal output ratio of the gas turbine and the thermal storage system through optimization algorithms, generating an economic optimization strategy to minimize the comprehensive cost while meeting operational constraints.

[0107] In some implementations, after meeting the economic optimization requirements, when there is a surplus of renewable energy or the risk of curtailment, a low-carbon operation strategy is generated by implementing the low-carbon operation principle. The low-carbon operation strategy is to drive a thermochemical endothermic reaction to achieve thermal storage operation.

[0108] After meeting economic optimization requirements, when there is a surplus of renewable energy or a risk of power curtailment, the principle priority decision module executes the low-carbon operation principle to generate a low-carbon operation strategy. This strategy involves driving a thermochemical endothermic reaction to achieve thermal energy storage operation. The low-carbon operation principle is used to convert excess electrical or thermal energy into chemical energy for storage through a thermochemical thermal energy storage system when there is a surplus of renewable energy generation or a risk of power curtailment on the grid, thereby reducing fossil fuel consumption and overall carbon emissions.

[0109] When there is a surplus of renewable energy generation such as wind and solar power in the power grid, the grid dispatch center may require thermal power units to reduce their output to absorb renewable energy. If gas turbines continue to operate at their rated load, this will crowd out the grid connection space for renewable energy. The principle priority decision module obtains renewable energy generation forecast data and grid dispatch instructions through the state perception module. When a surplus of renewable energy or a risk of power curtailment is detected, the low-carbon operation principle is prioritized, provided that safety constraints, stable steam supply, equipment lifespan protection, and economic optimization requirements are met. This principle drives thermochemical endothermic reactions to achieve thermal storage operation: For systems using fixed-bed reactors, the electric heating system is activated to heat the heat transfer gas and send it into the heat transfer gas channel of the fixed-bed thermochemical reactor. Through heat transfer via the indirect wall, the thermal storage medium undergoes an endothermic decomposition reaction, storing the excess energy during periods of renewable energy surplus as chemical energy. For systems using fluidized-bed reactors, the heat source unit heats the solid particles in the particle absorber, causing the particles to undergo an endothermic decomposition reaction, storing the excess energy in the high-temperature particles. Through this thermal energy storage operation mode, the system converts renewable energy that might otherwise be abandoned into chemical energy storage. When the grid load increases, the heat is released in the heat release mode to drive the steam turbine to generate electricity, realizing the transfer and utilization of renewable energy on a time scale, reducing the system's dependence on fossil fuels and the overall carbon emission level.

[0110] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined cycle power generation system coupling thermochemical thermal storage and a gas turbine waste heat boiler, characterized in that, include: Gas turbine power generation system, used to burn fuel to generate electricity and output high-temperature flue gas; A thermochemical thermal energy storage system includes a heat source unit and a thermal energy storage unit; the heat source unit is used to provide thermal energy for the endothermic reaction of the thermal energy storage unit; the thermal energy storage unit is used to absorb and store thermal energy in the thermal energy storage stage through a reversible chemical reaction, and release thermal energy to the thermochemical thermal energy storage side of the waste heat boiler heat exchange system in the heat release stage. The waste heat boiler heat exchange system includes at least a flue gas side, a thermochemical heat storage side, and a steam-water side. The flue gas side is connected to the flue gas outlet of the gas turbine power generation system for introducing the high-temperature flue gas. The thermochemical heat storage side is connected to the heat release output end of the thermochemical heat storage system for introducing the heat energy released by the thermochemical heat storage system. The steam-water side is used to introduce feedwater and output steam. The waste heat boiler heat exchange system uses the heat input from the flue gas side and the thermochemical heat storage side to heat the feedwater to generate steam. A steam turbine power generation system includes a steam inlet connected to the steam-water side outlet of the waste heat boiler heat exchange system, for generating electricity by utilizing the steam.

2. The system according to claim 1, characterized in that, The gas turbine power generation system includes a gas turbine generator (1), a compressor (2), a combustion chamber (3), and a gas turbine section (4). The outlet of the compressor (2) is connected to the inlet of the combustion chamber (3), the outlet of the combustion chamber (3) is connected to the inlet of the gas turbine section (4), and the gas turbine section (4) is coaxially connected to the gas turbine generator (1). The waste heat boiler heat exchange system includes a waste heat boiler (5). The flue gas side of the waste heat boiler (5) is connected to the exhaust port of the turbine section (4) of the gas turbine. The steam-water side outlet of the waste heat boiler (5) is connected to the steam inlet of the turbine unit (7) of the steam turbine power generation system. The turbine unit (7) is coaxially connected to the turbine generator (8). The exhaust port of the turbine unit (7) is sequentially connected to the condenser (9), the feed water pump (10), and the feed water heater (11). The outlet of the feed water heater (11) is connected to the steam-water side inlet of the waste heat boiler (5), forming a closed water-steam cycle.

3. The system according to claim 2, characterized in that, The thermal storage unit includes a fixed-bed thermochemical reactor (15), a reaction gas control valve (151), and a reaction gas preheater (16). The fixed-bed thermochemical reactor (15) is filled with thermochemical heat storage medium and adopts a partitioned heat exchange structure. The reaction zone is isolated from the heat carrier gas channel, and the partitioned heat exchange and reaction heat exchange are achieved through the heat carrier gas. In the heat storage mode, the heat-carrying gas is heated by the heat source unit and then enters the heat-carrying gas channel of the fixed bed thermochemical reactor (15). Through heat transfer through the partition wall, the thermochemical heat storage medium undergoes an endothermic decomposition reaction, converting thermal energy into chemical energy for storage. In the exothermic mode, the reaction gas is heated by the reaction gas preheater (16) and then enters the reaction zone of the fixed bed thermochemical reactor (15) through the reaction gas control valve (151). It reacts with the thermochemical heat storage medium to produce an exothermic reaction. The released chemical heat is transferred to the heat carrier gas channel through the partition wall. The heated heat carrier gas is then transported to the thermochemical heat storage side of the waste heat boiler (5).

4. The system according to claim 3, characterized in that, The heat source unit is a photothermal concentrating heat collection system or an electric heating system; The solar thermal concentrating system includes a heliostat field (12), a solar thermal concentrating system (13), and a receiver (14). The receiver (14) is located at the focal point of the solar thermal concentrating system (13) and is used to focus solar radiation to heat the air. The outlet of the receiver (14) is connected to the inlet of the heat-carrying gas channel of the fixed bed thermochemical reactor (15). The electric heating system includes a grid off-peak electricity or abandoned electricity input interface (18) and an electric heating device (19). The inlet of the electric heating device (19) is used to introduce air, and the outlet of the electric heating device (19) is connected to the heat-carrying gas channel inlet of the fixed bed thermochemical reactor (15).

5. The system according to claim 2, characterized in that, The thermal storage unit includes a high-temperature particle storage tank (21), a high-temperature side particle circulation pump (22), a low-temperature particle storage tank (23), and a low-temperature side particle circulation pump (24). The outlet of the low-temperature particle storage tank (23) is connected to the inlet of the low-temperature side particle circulation pump (24), and the outlet of the low-temperature side particle circulation pump (24) is connected to the inlet of the high-temperature particle storage tank (21). The heat source unit is used to heat the particles between the outlet of the low-temperature side particle circulation pump (24) and the channel of the high-temperature particle storage tank (21). The outlet of the high-temperature particle storage tank (21) is connected to the inlet of the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler (5) via the high-temperature side particle circulation pump (22). The outlet of the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler (5) is connected to the inlet of the low-temperature particle storage tank (23), forming a closed solid particle circulation loop. In the heat storage mode, the low-temperature particles are transported to the high-temperature particle storage tank (21) by the low-temperature side particle circulation pump (24). The heat source unit heats the particles before they enter the high-temperature particle storage tank (21) to cause the particles to undergo an endothermic decomposition reaction, converting thermal energy into chemical energy for storage. The high-temperature particles after the reaction enter the high-temperature particle storage tank (21). In the exothermic mode, high-temperature particles are transported to the gas-solid reaction heat exchange chamber at the front end of the waste heat boiler (5) via the high-temperature side particle circulation pump (22), where they come into contact with the reaction gas and undergo an exothermic reaction. The released chemical heat and particle sensible heat together heat the steam-water side of the waste heat boiler (5), and the low-temperature particles after the reaction enter the low-temperature particle storage tank (23).

6. The system according to claim 5, characterized in that, The heat source unit is a photothermal concentrating heat collection system or an electric heating system; The solar thermal concentrating system includes a heliostat field (12), a solar thermal concentrating system (13), and a particle heat absorber (20). The particle heat absorber (20) is located between the low-temperature particle circulation pump (24) and the high-temperature particle storage tank (21). The particle heat absorber (20) is located at the focal point of the solar thermal concentrating system (13) and is used to focus solar radiation to heat the particles in the particle heat absorber (20). The electric heating system includes a grid off-peak electricity or abandoned electricity input interface (18) and an electric heating device (19). The electric heating device (19) is located on the particle conveying channel between the low-temperature side particle circulation pump (24) and the high-temperature particle storage tank (21), or inside the high-temperature particle storage tank (21), and is used to heat the particles using electric energy during periods of low-priced electricity.

7. The system according to any one of claims 3-6, characterized in that, When the medium of the reversible chemical reaction is a carbonate system or a metal hydride system, the thermochemical thermal storage system further includes a reaction gas supply device (17), the outlet of which is connected to the inlet of the reaction gas preheater (16) to provide the reaction gas corresponding to the medium of the reversible chemical reaction.

8. The system according to claim 1, characterized in that, The system also includes an intelligent control system, which includes: The status sensing module is used to collect system operating parameters, including grid load demand, load change rate, gas turbine exhaust temperature, steam pressure and steam flow of waste heat boiler (5), and bed temperature of fixed bed thermochemical reactor (15) or granular heat absorber (20). The principle priority decision module, connected to the state perception module, is used to generate control strategies based on safety constraint principles, steam supply stability principles, equipment life protection principles, operational economy principles, and low-carbon operation principles. The operation mode management module, connected to the principle priority decision module, is used to output control signals to each actuator according to the generated control strategy, so as to realize the dynamic coordinated control of the gas turbine heat source and the thermochemical thermal storage heat source.

9. The system according to claim 8, characterized in that, The principle priority decision module is also used for: According to the preset safety constraint principle, it is determined whether the system meets the safe operation conditions. If the bed temperature of the fixed bed thermochemical reactor (15) or the particle heat absorber (20) exceeds the preset safety upper limit, the bed temperature difference exceeds the allowable range, the main steam pressure of the waste heat boiler (5) exceeds the safety threshold, the heat exchange wall temperature of the waste heat boiler (5) exceeds the material allowable temperature, the fluidization state of the fluidized bed is abnormal, or the concentration of the reactant gas is abnormal, a safety protection strategy is generated. The safety protection strategy is to reduce the thermochemical reaction rate or exit the heat release operation state and limit the gas turbine load change rate. After meeting the safety constraints, the main steam pressure or temperature is judged to be deviated from the set value according to the steam supply stability principle. If a deviation occurs, a steam supply stability strategy is generated. The steam supply stability strategy is to restore the main steam parameters to the stable range by adjusting the thermochemical heat release power, the opening of the steam bypass valve, or the gas turbine load. After meeting the requirements for stable steam supply, a life protection strategy is generated according to the equipment life protection principle. The life protection strategy is to limit the rate of change of bed temperature and the rate of change of thermochemical heat release power of the fixed bed thermochemical reactor (15) or the particle heat absorber (20) in order to reduce thermal shock and material fatigue. After meeting the equipment life protection requirements, an economic optimization strategy is generated based on the principle of operational economy. The economic optimization strategy is to optimize the allocation ratio of gas turbine output and thermochemical heat storage heat release power to minimize the comprehensive value of fuel consumption cost, unit start-up and shutdown loss and carbon emission cost.

10. The system according to claim 9, characterized in that, After meeting the requirements for economic optimization, when there is a surplus of renewable energy or the risk of curtailment, the low-carbon operation principle is implemented to generate a low-carbon operation strategy, which is to drive thermochemical endothermic reaction to achieve thermal storage operation.

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