Thermal power plant waste heat thermochemical storage coupling oxygen-enriched combustion utilization system and method

Abstract

The invention relates to the technical field of energy storage, and discloses a thermal power plant waste heat thermochemical storage coupling oxygen-enriched combustion utilization system and method.The heat energy output end of a thermal power plant high-temperature flue gas / steam bypass is connected to the heat energy input end of a thermochemical energy storage and release reaction unit, and necessary heat energy is provided for an energy storage reactor; meanwhile, heat carried by flue gas of the thermal power plant and heat carried by steam which is easily wasted during low-load operation are fully utilized, so that the utilization efficiency of heat energy of the thermal power plant is improved, and energy waste is reduced or avoided; the thermal chemical energy storage and release reaction unit and the energy storage reaction material storage container are sequentially and circularly connected to form a loop, an energy storage chemical reaction product can be simply and conveniently regenerated through oxidation reaction, released heat is recycled, and waste heat storage and efficient utilization, energy conservation and consumption reduction of a thermal power plant are effectively achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to a system and method for utilizing waste heat from a thermal power plant coupled with oxygen-enriched combustion. Background Art

[0002] Thermal power plants often generate heat energy that is not fully used for power generation during the power generation process. This waste heat can be recovered and utilized through different technologies, such as using low-temperature economizer equipment to recover flue gas waste heat to heat boiler feed water, thereby improving energy conversion efficiency and reducing energy waste. However, there is still a lot of energy loss in the process of flue gas emissions and water circulation. The combustion of fossil fuels also produces a large amount of carbon dioxide emissions, making energy conservation, consumption reduction and emission reduction the primary goal that thermal power plants need to achieve. On the other hand, oxygen-enriched combustion technology uses pure oxygen or oxygen-enriched air as a combustion-supporting gas to make the fuel burn more completely, which not only improves combustion efficiency and heat utilization, but also helps to reduce pollutant emissions and improve the efficiency of subsequent carbon capture. These characteristics make the application of oxygen-enriched combustion technology in thermal power plants have important environmental and economic value, but at the same time, it also increases the operating cost of thermal power plants because of the need to provide high concentrations of oxygen.

[0003] Thermochemical energy storage technology stores and releases energy through reversible chemical reactions. It is an emerging and efficient energy storage method. Thermochemical heat storage converts thermal energy into chemical energy of energy storage materials for storage. It can provide a greater energy storage density than sensible heat storage and latent heat storage, and achieve long-term energy storage and long-distance transportation and reuse. Generally, thermochemical energy storage technology requires the use of reversible reactions of decomposition and synthesis of energy storage materials such as carbonates, hydroxides, metal hydrides, and metal oxides. A large amount of gaseous products are produced during the endothermic decomposition process, which increases the difficulty and cost of storing gaseous products. At the same time, current thermochemical energy storage technology is mainly used in the fields of concentrated solar energy storage and solar thermal power generation. The intermittent nature of solar energy also brings challenges to the start and stop process of the thermochemical energy storage reaction system. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a system and method for thermochemical storage of waste heat from a thermal power plant coupled with oxygen-enriched combustion utilization, so as to solve the technical problem of how to improve the storage and efficient utilization of waste heat in a thermal power plant in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] In the first aspect, the present invention provides a system for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, comprising a high-temperature flue gas / steam bypass of the thermal power plant, a thermochemical energy storage and release reaction unit, an energy storage reaction material storage container and an oxygen-enriched combustion system; the thermal energy output end of the high-temperature flue gas / steam bypass of the thermal power plant is connected to the thermal energy input end of the thermochemical energy storage and release reaction unit, the material output end of the thermochemical energy storage and release reaction unit is connected to the input end of the energy storage reaction material storage container, and the output end of the energy storage reaction material storage container is connected to the material input end of the thermochemical energy storage and release reaction unit to form a circulation loop; the oxygen output end of the thermochemical energy storage and release reaction unit is connected to the oxygen-enriched combustion system.

[0007] Preferably, the thermochemical energy storage and release reaction unit comprises an energy storage reactor, an energy release reactor and a solid oxygen storage unit;

[0008] The heat energy input end of the energy storage reactor is connected to the high-temperature flue gas / steam bypass of the thermal power plant; the solid-gas output end of the energy storage reactor is connected to the solid oxygen storage unit, the solid product output end of the solid oxygen storage unit is connected to the input end of the energy release reactor, and the material output end of the energy release reactor is connected to the energy storage reaction material storage container; the gas product output end of the solid oxygen storage unit is connected to the oxygen-enriched combustion system.

[0009] Preferably, the solid oxygen storage unit comprises a solid product storage container and an oxygen storage tank;

[0010] The solid product output end of the energy storage reactor is connected to the input end of the solid product storage container; the output end of the solid product storage container is connected to the input end of the energy release reactor;

[0011] The gas product output end of the energy storage reactor is connected to the input end of the oxygen storage tank; and the output end of the oxygen storage tank is connected to the input end of the energy release reactor.

[0012] Furthermore, the energy release reactor is provided with a gas input port for inputting air or oxygen.

[0013] In a second aspect, the present invention further provides a method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, based on the above-mentioned system for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, comprising the following process:

[0014] The high-temperature flue gas / steam bypass of the thermal power plant provides thermal energy to the energy storage reactor, and the energy storage material in the energy storage reactor undergoes an energy storage endothermic chemical reaction, and the solid product produced by the energy storage endothermic chemical reaction is transported to the solid product storage container, and the oxygen product is transported to the oxygen storage tank at the same time; the solid product storage container transports the solid product to the energy release reactor, and an exothermic reverse reaction of the energy storage endothermic chemical reaction occurs in the energy release reactor, and the product of the exothermic reverse reaction of the energy storage endothermic chemical reaction is transported to the energy storage reaction material storage container for providing energy storage material to the energy storage reactor; the oxygen in the oxygen storage tank is transported to the oxygen-enriched combustion system for providing oxygen to the oxygen-enriched combustion system.

[0015] Furthermore, the energy storage material in the energy storage reactor is M x O (y+2z) , the thermal energy provided to the energy storage reactor by the high-temperature flue gas / steam bypass of the thermal power plant causes the energy storage material in the energy storage reactor to undergo an energy storage endothermic chemical reaction. The specific reaction formula is as follows:

[0016] M x O (y+2z) +△H→M x O y +zO2

[0017] Among them, M x O y It is the solid product of the energy storage chemical reaction; O2 is the gaseous product of the energy storage chemical reaction.

[0018] Furthermore, the energy storage material M x O (y+2z) M is a metal material, and M includes one or more of Ba, Co, Mn, Cu, Fe and Zn, as well as alloys composed of M and composite materials doped with other substances.

[0019] Furthermore, the solid product of the energy storage endothermic chemical reaction undergoes an exothermic reverse reaction of the energy storage endothermic chemical reaction in the energy release reactor. The specific reaction formula is as follows:

[0020] M x O y +zO2→M x O (y+2z) +△H;

[0021] Among them, M x O (y+2z) For energy storage materials.

[0022] Furthermore, the solid product of the energy storage endothermic chemical reaction undergoes an exothermic reverse reaction of the energy storage endothermic chemical reaction in the energy release reactor, by inputting air or pure oxygen into the energy release reactor as a reactant of the reverse reaction, and the air serves as a thermal energy medium.

[0023] Furthermore, the oxygen in the oxygen storage tank is transported to the oxygen-enriched combustion system, which uses pure oxygen or oxygen-enriched air as the combustion-supporting gas. The combustion forms include slightly oxygen-enriched combustion, oxygen spray gun, pure oxygen combustion and air-oxygen combustion.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] The present invention provides a system for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion. The heat output end of the high-temperature flue gas / steam bypass of the thermal power plant is connected to the heat input end of the thermochemical energy storage and release reaction unit, providing necessary heat energy for the energy storage reactor. At the same time, the heat carried by the flue gas of the thermal power plant and the heat carried by the steam that is easily wasted during low-load operation are fully utilized, thereby improving the utilization efficiency of the thermal energy of the thermal power plant and reducing or avoiding energy waste. The thermochemical energy storage and release reaction unit and the energy storage reaction material storage container are connected in a circular manner in sequence to form a loop. The energy storage chemical reaction product can be simply regenerated and released through an oxidation reaction for recycling and utilization, effectively realizing the storage and efficient utilization of waste heat from the thermal power plant and energy saving and consumption reduction. At the same time, the oxygen output end of the thermochemical energy storage and release reaction unit is connected to the oxygen-enriched combustion system, realizing continuous storage of waste heat from the thermal power plant and reduction of pollutant emissions, and ensuring stable operation of the thermal power plant during low-load periods.

[0026] Furthermore, the thermochemical energy storage and release reaction unit includes an energy storage reactor, an energy release reactor and a solid oxygen storage unit; the heat energy input end of the energy storage reactor is connected to the high-temperature flue gas / steam bypass of the thermal power plant; the solid gas output end of the energy storage reactor is connected to the solid oxygen storage unit, the solid product output end of the solid oxygen storage unit is connected to the input end of the energy release reactor, and the material output end of the energy release reactor is connected to the energy storage reaction material storage container; the gas product output end of the solid oxygen storage unit is connected to the oxygen-enriched combustion system; the energy storage reactor uses the flue gas or steam from the high-temperature flue gas bypass or steam bypass of the thermal power plant as the fuel. The heat medium fluid can stably supply the required heat for the energy storage reaction; the energy storage reactor stores the solid products and gas products separately through the solid oxygen storage unit and then transports them to the energy release reactor and the oxygen-enriched combustion system. The solid products are output in the energy release reactor to obtain energy storage materials, which greatly improves the recycling of energy storage materials. The oxygen-enriched combustion system uses pure oxygen or oxygen-enriched air as a combustion-supporting gas for combustion, which can reduce the theoretical amount of air for fuel combustion in the boiler of a thermal power plant, speed up the fuel combustion rate, increase the theoretical flame temperature, and reduce flue gas emissions, thereby reducing pollutants and carbon dioxide emissions.

[0027] The present invention also provides a method for utilizing waste heat from a thermal power plant by coupling thermochemical storage with oxygen-enriched combustion, wherein an energy storage endothermic chemical reaction occurs in the energy storage material in the energy storage reactor, and the solid product produced by the energy storage endothermic chemical reaction is transported to a solid product storage container, and the oxygen product is transported to an oxygen storage tank at the same time; the solid product storage container transports the solid product to an energy release reactor, an exothermic reverse reaction of the energy storage endothermic chemical reaction occurs in the energy release reactor, and the product of the exothermic reverse reaction of the energy storage endothermic chemical reaction is transported to an energy storage reaction material storage container for providing energy storage material to the energy storage reactor; the oxygen in the oxygen storage tank is transported to an oxygen-enriched combustion system, which can realize continuous storage of waste heat from the thermal power plant and ensure stable operation of the thermal power plant during low-load periods, while replacing an air separation unit and providing oxygen for the oxygen-enriched combustion system of the thermal power plant, and the energy storage chemical reaction product can be simply regenerated through an oxidation reaction and released heat for recycling, thereby achieving the purposes of storing and efficiently utilizing waste heat from the thermal power plant, saving energy and reducing consumption, and reducing pollutant emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of a system for thermochemical storage of waste heat from a thermal power plant coupled with oxygen-enriched combustion utilization in an embodiment of the present invention.

[0029] In the figure: 1- high temperature flue gas / steam bypass of thermal power plant; 2- energy storage reactor; 3- solid product storage container; 4- energy release reactor; 5- energy storage reaction material storage container; 6- oxygen storage tank; 7- oxygen-enriched combustion system; DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0033] The object of the present invention is to provide a system and method for utilizing waste heat from a thermal power plant in a thermochemical manner coupled with oxygen-enriched combustion, so as to solve the technical problem in the prior art of how to improve the storage and efficient utilization of waste heat from a thermal power plant.

[0034] Example 1

[0035] See also Figure 1 In one embodiment of the present invention, a system for utilizing waste heat from a thermal power plant coupled with thermochemical storage and oxygen-enriched combustion is provided, comprising a high-temperature flue gas / steam bypass 1 of the thermal power plant, a thermochemical energy storage and release reaction unit, an energy storage reaction material storage container 5 and an oxygen-enriched combustion system 7; the thermal energy output end of the high-temperature flue gas / steam bypass 1 of the thermal power plant is connected to the thermal energy input end of the thermochemical energy storage and release reaction unit, the material output end of the thermochemical energy storage and release reaction unit is connected to the input end of the energy storage reaction material storage container 5, and the output end of the energy storage reaction material storage container 5 is connected to the material input end of the thermochemical energy storage and release reaction unit to form a circulation loop; the oxygen output end of the thermochemical energy storage and release reaction unit is connected to the oxygen-enriched combustion system 7.

[0036] Specifically, the thermochemical energy storage and release reaction unit includes an energy storage reactor 2, an energy release reactor 4 and a solid oxygen storage unit;

[0037] The heat energy input end of the energy storage reactor 2 is connected to the high-temperature flue gas / steam bypass 1 of the thermal power plant; the solid-gas output end of the energy storage reactor 2 is connected to the solid oxygen storage unit, the solid product output end of the solid oxygen storage unit is connected to the input end of the energy release reactor 4, and the material output end of the energy release reactor 4 is connected to the energy storage reaction material storage container 5; the gas product output end of the solid oxygen storage unit is connected to the oxygen-enriched combustion system 7.

[0038] Specifically, the solid oxygen storage unit includes a solid product storage container 3 and an oxygen storage tank 6;

[0039] The solid product output end of the energy storage reactor 2 is connected to the input end of the solid product storage container 3; the output end of the solid product storage container 3 is connected to the input end of the energy release reactor 4;

[0040] The gas product output end of the energy storage reactor 2 is connected to the input end of the oxygen storage tank 6 ; the output end of the oxygen storage tank 6 is connected to the input end of the energy release reactor 4 .

[0041] The energy release reactor 4 is provided with a gas input port for inputting air or oxygen.

[0042] In this embodiment, the high-temperature flue gas / steam bypass 1 of the thermal power plant refers to a bypass that leads out a part of the high-temperature flue gas from the turning chamber of the thermal power plant boiler, or a bypass that leads out a part of the high-temperature and high-pressure steam from the boiler to the steam turbine, and is mainly composed of a bypass valve, a bypass pipeline, a heating pipe facility, and a corresponding control system. Its main function is to provide the necessary heat energy for the energy storage reactor, and at the same time make full use of the heat carried by the flue gas of the thermal power plant and the heat carried by the steam that is easily wasted during low-load operation, thereby improving the utilization efficiency of the thermal energy of the thermal power plant and reducing or avoiding energy waste. The type and facilities of the bypass are selected and designed according to the reaction temperature requirements of the energy storage reactor 2.

[0043] In this embodiment, the energy storage reactor 2 is the place where the energy storage endothermic chemical reaction occurs. The flue gas or steam from the high-temperature flue gas / steam bypass 1 of the thermal power plant is used as the heating medium fluid, which can stably supply the required heat for the energy storage reaction. The type of the energy storage reactor can be a fixed bed reactor, a fluidized bed reactor, a moving bed reactor, etc.

[0044] In this embodiment, the solid product storage container 3 refers to a container that can stably store the solid products of the energy storage endothermic chemical reaction. It is required to be able to adapt to the storage conditions of the reaction products and can be conveniently transported to the location where it is needed, and then connected to the energy release reactor 4.

[0045] In this embodiment, the energy release reactor 4 is the place where the exothermic reverse reaction of the energy storage endothermic chemical reaction and the regeneration of the energy storage material occur. The energy storage material generated by the exothermic reverse reaction is transported to the energy storage reaction material storage container 5 for storage.

[0046] In this embodiment, the energy storage reaction material storage container 5 refers to a container that can stably store energy storage materials, is required to be able to adapt to the storage conditions of the energy storage materials, and can be conveniently transported and connected to the energy storage reactor 2.

[0047] In this embodiment, the oxygen storage tank 6 is a container that can stably store the energy-storing endothermic chemical reaction gas product O2, and supplies oxygen to the oxygen-enriched combustion system 7 of the thermal power plant.

[0048] In this embodiment, the oxygen-enriched combustion system 7 is a boiler combustion technology system in a thermal power plant that uses pure oxygen or oxygen-enriched air as a combustion-supporting gas. It can be in the form of slightly oxygen-enriched combustion, oxygen spray gun, pure oxygen combustion, air-oxygen combustion, etc., and uses oxygen transported from the oxygen storage tank 6 as the oxygen source, and no longer requires an air separation unit. The system can reduce the theoretical air volume for fuel combustion in the thermal power plant boiler, speed up the fuel combustion speed, increase the theoretical flame temperature, reduce the flue gas emissions, and thus reduce the pollutants and carbon dioxide emissions.

[0049] In summary, the present invention provides a system for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, wherein the heat output end of the high-temperature flue gas / steam bypass of the thermal power plant is connected to the heat input end of the thermochemical energy storage and release reaction unit, providing necessary heat energy for the energy storage reactor, while making full use of the heat carried by the flue gas of the thermal power plant and the heat carried by the steam that is easily wasted during low-load operation, thereby improving the utilization efficiency of the thermal energy of the thermal power plant and reducing or avoiding energy waste; the thermochemical energy storage and release reaction unit and the energy storage reaction material storage container are connected in a circular manner in sequence to form a loop, and the energy storage chemical reaction product can be simply regenerated and released through an oxidation reaction for recycling and utilization, effectively realizing the storage and efficient utilization of waste heat from the thermal power plant and energy saving and consumption reduction, and at the same time, the oxygen output end of the thermochemical energy storage and release reaction unit is connected to the oxygen-enriched combustion system, realizing continuous storage of waste heat from the thermal power plant and reduction of pollutant emissions, thereby ensuring stable operation of the thermal power plant during low-load periods.

[0050] Example 2

[0051] This embodiment 2 provides a method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, based on the above-mentioned system for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, including the following process:

[0052] The high-temperature flue gas / steam bypass 1 of the thermal power plant provides thermal energy to the energy storage reactor 2, and the energy storage material in the energy storage reactor 2 undergoes an energy storage endothermic chemical reaction, and the solid product produced by the energy storage endothermic chemical reaction is transported to the solid product storage container 3, and the oxygen product is transported to the oxygen storage tank 6; the solid product storage container 3 transports the solid product to the energy release reactor 4, and an exothermic reverse reaction of the energy storage endothermic chemical reaction occurs in the energy release reactor 4, and the product of the exothermic reverse reaction of the energy storage endothermic chemical reaction is transported to the energy storage reaction material storage container 5 for providing energy storage material to the energy storage reactor 2; the oxygen in the oxygen storage tank 6 is transported to the oxygen-enriched combustion system 7 for providing oxygen to the oxygen-enriched combustion system 7.

[0053] Specifically, the energy storage material in the energy storage reactor 2 is M x O (y+2z) , the thermal energy provided by the high-temperature flue gas / steam bypass 1 of the thermal power plant to the energy storage reactor 2 causes the energy storage material in the energy storage reactor 2 to undergo an energy storage endothermic chemical reaction. The specific reaction formula is as follows:

[0054] M x O (y+2z) +△H→M x O y +zO2

[0055] Among them, M x O y It is the solid product of the energy storage chemical reaction; O2 is the gaseous product of the energy storage chemical reaction.

[0056] Among them, the energy storage material M x O (y+2z) M is a metal material, including one or more of Ba, Co, Mn, Cu, Fe and Zn, as well as alloys composed of M and composite materials doped with other substances. x O (y+2z) / M x O y Material pairs include BaO2 / BaO, Co3O4 / CoO, Mn2O3 / Mn3O4, CuO / Cu2O, Fe2O3 / Fe3O4, ZnO / Zn, etc.

[0057] Specifically, the solid product of the energy storage endothermic chemical reaction undergoes an exothermic reverse reaction of the energy storage endothermic chemical reaction in the energy release reactor 4. The specific reaction formula is as follows:

[0058] M x O y +zO2→M x O (y+2z) +△H;

[0059] Among them, M x O (y+2z) For energy storage materials.

[0060] In this embodiment, the solid product of the energy storage endothermic chemical reaction undergoes an exothermic reverse reaction of the energy storage endothermic chemical reaction in the energy release reactor 4. By inputting air or pure oxygen into the energy release reactor 4 as a reactant for the reverse reaction, the air also serves as a thermal energy medium.

[0061] In this embodiment, the oxygen in the oxygen storage tank 6 is transported to the oxygen-enriched combustion system 7. The oxygen-enriched combustion system 7 uses pure oxygen or oxygen-enriched air as the combustion-supporting gas. The combustion forms include slightly oxygen-enriched combustion, oxygen spray gun, pure oxygen combustion and air-oxygen combustion.

[0062] In summary, the present embodiment provides a method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, wherein an energy storage endothermic chemical reaction occurs in the energy storage material in the energy storage reactor, and the solid product produced by the energy storage endothermic chemical reaction is transported to a solid product storage container, and the oxygen product is transported to an oxygen storage tank at the same time; the solid product storage container transports the solid product to an energy release reactor, an exothermic reverse reaction of the energy storage endothermic chemical reaction occurs in the energy release reactor, and the product of the exothermic reverse reaction of the energy storage endothermic chemical reaction is transported to an energy storage reaction material storage container for providing energy storage materials to the energy storage reactor; the oxygen in the oxygen storage tank is transported to the oxygen-enriched combustion system, which can realize continuous storage of waste heat from the thermal power plant and ensure stable operation of the thermal power plant during low-load periods, while replacing the air separation unit and providing oxygen for the oxygen-enriched combustion system of the thermal power plant, and the energy storage chemical reaction product can be simply regenerated through an oxidation reaction and released heat for recycling, thereby achieving the purpose of storing and efficiently utilizing waste heat from the thermal power plant, saving energy and reducing consumption, and reducing pollutant emissions.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A thermal power plant waste heat thermochemical storage coupled with oxygen-enriched combustion utilization system, characterized in that: It comprises a thermal power plant high-temperature flue gas / steam bypass (1), a thermochemical energy storage and release reaction unit, an energy storage reaction material storage container (5) and an oxygen-enriched combustion system (7); the thermal energy output end of the thermal power plant high-temperature flue gas / steam bypass (1) is connected to the thermal energy input end of the thermochemical energy storage and release reaction unit, the material output end of the thermochemical energy storage and release reaction unit is connected to the input end of the energy storage reaction material storage container (5), and the output end of the energy storage reaction material storage container (5) is connected to the material input end of the thermochemical energy storage and release reaction unit to form a circulation loop; the oxygen output end of the thermochemical energy storage and release reaction unit is connected to the oxygen-enriched combustion system (7).

2. A thermal power plant waste heat thermochemical storage coupled with oxygen-enriched combustion utilization system according to claim 1, characterized in that: The thermochemical energy storage and release reaction unit comprises an energy storage reactor (2), an energy release reactor (4) and a solid oxygen storage unit; The heat energy input end of the energy storage reactor (2) is connected to the high-temperature flue gas / steam bypass (1) of the thermal power plant; the solid-gas output end of the energy storage reactor (2) is connected to a solid oxygen storage unit, the solid product output end of the solid oxygen storage unit is connected to the input end of the energy release reactor (4), and the material output end of the energy release reactor (4) is connected to an energy storage reaction material storage container (5); the gas product output end of the solid oxygen storage unit is connected to an oxygen-enriched combustion system (7).

3. A thermal power plant waste heat thermochemical storage coupled with oxygen-enriched combustion utilization system according to claim 2, characterized in that: The solid oxygen storage unit comprises a solid product storage container (3) and an oxygen storage tank (6); The solid product output end of the energy storage reactor (2) is connected to the input end of the solid product storage container (3); the output end of the solid product storage container (3) is connected to the input end of the energy release reactor (4); The gas product output end of the energy storage reactor (2) is connected to the input end of the oxygen storage tank (6); and the output end of the oxygen storage tank (6) is connected to the input end of the energy release reactor (4).

4. A thermal power plant waste heat thermochemical storage coupled with oxygen-enriched combustion utilization system according to claim 2, characterized in that: The energy release reactor (4) is provided with a gas input port for inputting air or oxygen.

5. A method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion, characterized in that: A thermal power plant waste heat thermochemical storage coupled with oxygen-enriched combustion utilization system according to any one of claims 1 to 4 comprises the following processes: The high-temperature flue gas / steam bypass (1) of the thermal power plant provides thermal energy to the energy storage reactor (2), and the energy storage material in the energy storage reactor (2) undergoes an energy storage endothermic chemical reaction, and the solid product produced by the energy storage endothermic chemical reaction is transported to the solid product storage container (3), and the oxygen product is transported to the oxygen storage tank (6); the solid product storage container (3) transports the solid product to the energy release reactor (4), and an exothermic reverse reaction of the energy storage endothermic chemical reaction occurs in the energy release reactor (4), and the product of the exothermic reverse reaction of the energy storage endothermic chemical reaction is transported to the energy storage reaction material storage container (5) for providing energy storage material to the energy storage reactor (2); the oxygen in the oxygen storage tank (6) is transported to the oxygen-enriched combustion system (7) for providing oxygen to the oxygen-enriched combustion system (7).

6. The method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion according to claim 5, characterized in that: The energy storage material in the energy storage reactor (2) is M x O (y+2z) The thermal energy provided by the high-temperature flue gas / steam bypass (1) of the thermal power plant to the energy storage reactor (2) causes the energy storage material in the energy storage reactor (2) to undergo an energy storage endothermic chemical reaction. The specific reaction formula is as follows: M x THE (y+2z) +△H→M x THE y +zO2 Among them, M x O y It is the solid product of the energy storage chemical reaction; O2 is the gaseous product of the energy storage chemical reaction.

7. The method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion according to claim 6, characterized in that: The energy storage material M x O (y+2z) M is a metal material, including one or more of Ba, Co, Mn, Cu, Fe and Zn, as well as alloys composed of M and composite materials doped with other substances.

8. The method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion according to claim 6, characterized in that: The solid product of the energy storage endothermic chemical reaction undergoes an exothermic reverse reaction of the energy storage endothermic chemical reaction in the energy release reactor (4). The specific reaction formula is as follows: M x O y +zO2→M x O (y+2z) +△H; Among them, M x O (y+2z) For energy storage materials.

9. The method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion according to claim 8, characterized in that: The solid product of the energy storage endothermic chemical reaction undergoes an exothermic reverse reaction of the energy storage endothermic chemical reaction in the energy release reactor (4), and air or pure oxygen is introduced into the energy release reactor (4) as a reactant of the reverse reaction, and air is used as a thermal energy medium.

10. The method for utilizing waste heat from a thermal power plant by thermochemical storage coupled with oxygen-enriched combustion according to claim 8, characterized in that: The oxygen in the oxygen storage tank (6) is transported to the oxygen-enriched combustion system (7). The oxygen-enriched combustion system (7) uses pure oxygen or oxygen-enriched air as the combustion-supporting gas. The combustion forms include slightly oxygen-enriched combustion, oxygen spray gun, pure oxygen combustion and air-oxygen combustion.

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