CO₂-based thermochemical energy storage combined power generation system

Abstract

The present invention relates to the technical field of carbon dioxide power generation, and particularly relates to a thermochemical energy storage combined power generation system based on carbon dioxide, comprising: a first thermochemical reactor and a high-temperature turbine connected in sequence; further comprising: a second thermochemical reactor, the inlet end of the tube layer and the inlet end of the shell layer of which are both communicated with the outlet end of the high-temperature turbine; the first thermochemical reactor is filled with a carbon dioxide reversible release material, and the second thermochemical reactor is filled with a carbon dioxide reversible absorption material. The storage treatment of excess carbon dioxide has much lower treatment difficulty and energy consumption than that of carbon dioxide in waste gas. At the same time, during the process of storing carbon dioxide through the thermochemical energy storage combined power generation system based on carbon dioxide, the high-temperature turbine can be driven to operate and generate electricity, and the energy in the waste gas can be fully utilized, which can greatly reduce the energy consumption during the treatment of carbon dioxide waste gas in thermal power plants.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide power generation, and particularly to a thermochemical energy storage combined power generation system based on carbon dioxide. Background Art

[0002] In the traditional energy industry, the large-scale emission of carbon dioxide has caused serious environmental problems. Globally, the major large-scale emission sources of carbon dioxide are power plant emission sources and other industrial emission sources. Among them, thermal power plants mainly using fossil fuels are the largest fixed emission sources of carbon dioxide, discharging a large amount of carbon dioxide into the atmosphere during the power generation process, and the carbon dioxide in the flue gas of power plants accounts for 37.5% of the total carbon emissions.

[0003] In the prior art, in order to reduce the carbon emissions of thermal power plants, the chemical absorption decarbonization technology based on monoethanolamine (MEA) is usually used to decarbonize the waste gas discharged from power plants, resulting in a large amount of low-grade waste heat. When using calcium looping to decarbonize traditional thermal power, due to the too high reaction temperature of the thermal chemical reaction of calcium-based particles, the power generation system needs to output heat energy to the decarbonization system, resulting in a large amount of energy efficiency loss. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that a large amount of heat energy needs to be input during the decarbonization treatment of the waste gas discharged by thermal power plants in the prior art, resulting in waste of effective energy, so as to provide a thermochemical energy storage combined power generation system based on carbon dioxide.

[0005] To solve the above technical problem, the present invention provides a thermochemical energy storage combined power generation system based on carbon dioxide, including: a first thermochemical reactor and a high-temperature turbine connected in sequence;

[0006] It further includes: a second thermochemical reactor, the inlet end of the tube layer and the inlet end of the shell layer of which are both communicated with the outlet end of the high-temperature turbine;

[0007] The first thermochemical reactor is filled with a carbon dioxide reversible release material, and the second thermochemical reactor is filled with a carbon dioxide reversible absorption material.

[0008] Optionally, it further includes a second heat exchanger, the heat exchange side of which is communicated with the shell layer of the second thermochemical reactor to perform heat exchange with the tube layer of the second thermochemical reactor, the heat supply side of which is communicated with both ends of a steam turbine, and a water storage tank is connected between the second heat exchanger and the steam turbine.

[0009] Optionally, the high-temperature turbine and the steam turbine are connected by a shaft.

[0010] Optionally, the inlet and outlet sides of the shell layer of the first thermochemical reactor are communicated with a first heat exchanger.

[0011] Optionally, an inlet end of a tube layer of the first thermochemical reactor is further connected to a carbon dioxide storage tank, and an outlet end of the tube layer of the second thermochemical reactor communicates between the first thermochemical reactor and the carbon dioxide storage tank.

[0012] Optionally, the carbon dioxide reversible release material is one or more of BaCO3, SrCO3, Li2CO3, CaCO3, and perovskite oxides.

[0013] Optionally, the carbon dioxide reversible absorption material is one or more of CaO, MgO, ZnO, PbO, perovskite oxides, and zeolites.

[0014] Optionally, a pressure regulating device is installed at an outlet end of the carbon dioxide storage tank.

[0015] The technical solution of the present invention has the following advantages:

[0016] 1. The thermochemical energy storage combined power generation system based on carbon dioxide provided by the present invention includes: a first thermochemical reactor and a high-temperature turbine connected in sequence; further includes: a second thermochemical reactor, an inlet end of a tube layer and an inlet end of a shell layer of which are both communicated with an outlet end of the high-temperature turbine; the first thermochemical reactor is filled with a carbon dioxide reversible release material, and the second thermochemical reactor is filled with a carbon dioxide reversible absorption material.

[0017] When the combined power generation system based on carbon dioxide thermochemical energy storage is connected to the thermal power generation system of a thermal power plant, during the energy storage process of the combined power generation system, the waste heat of the exhaust gas of the thermal power plant is transported to the first thermochemical reactor, causing the carbonate endothermic decomposition reaction to occur in the carbon dioxide reversible release material filling substance in the first thermochemical reactor, and generating solid oxides that remain in the first thermochemical reactor. The generated high-temperature carbon dioxide directly drives the high-temperature turbine to generate electricity. At this time, the pipeline between the inlet end of the tube layer of the second thermochemical reactor and the high-temperature turbine is opened, and the pipeline between the inlet end of the shell layer of the second thermochemical reactor and the high-temperature turbine is closed. The carbon dioxide at the outlet of the high-temperature turbine enters the tube layer of the second thermochemical reactor and reacts with the carbon dioxide reversible absorption material in the second thermochemical reactor to absorb carbon dioxide and produce carbonate stored in the second thermochemical reactor. During the energy release process of the combined power generation system, the exhaust gas with carbon dioxide in the thermal power plant is directly introduced into the first thermochemical reactor as a gas source. Among them, the carbon dioxide reacts with the material in the first thermochemical reactor and is absorbed. The heat released during the reaction heats the remaining exhaust gas to raise its temperature, and the heated exhaust gas is introduced into the high-temperature turbine to generate electricity. At this time, the pipeline between the inlet end of the tube layer of the second thermochemical reactor and the high-temperature turbine is closed, and the pipeline between the inlet end of the shell layer of the second thermochemical reactor and the high-temperature turbine is opened. The gas output from the high-temperature turbine enters the shell layer of the second thermochemical reactor to heat the second thermochemical reactor, causing the reversible absorption material that has absorbed carbon dioxide during the energy storage process in the second thermochemical reactor to undergo an endothermic decomposition reaction and release carbon dioxide. After the fillers inside the first thermochemical reactor and the second thermochemical reactor both return to the initial state, the energy release process ends. The storage treatment of excess carbon dioxide has much lower treatment difficulty and energy consumption for pure carbon dioxide than for carbon dioxide in exhaust gas. At the same time, during the process of storing carbon dioxide through the combined power generation system based on carbon dioxide thermochemical energy storage, it can also drive the high-temperature turbine to operate and generate electricity, making full use of the energy in the exhaust gas, and greatly reducing the energy consumption during the treatment of carbon dioxide exhaust gas in the thermal power plant.

[0018] 2. The combined power generation system based on carbon dioxide thermochemical energy storage provided by the present invention further includes a second heat exchanger. Its heat exchange side is connected to the shell layer of the second thermochemical reactor for heat exchange with the tube layer of the second thermochemical reactor, and its heat supply side is connected to both ends of the steam turbine. A water storage tank is connected between the second heat exchanger and the steam turbine. During the energy storage process, the second heat exchanger is used to absorb and utilize the heat generated by the reaction in the second thermochemical reactor, causing the water in the water storage tank to form steam to drive the steam turbine to operate and generate electricity, which can further improve the power generation efficiency in the combined power generation system and reduce the external energy consumption during carbon dioxide treatment.

[0019] 3. The combined power generation system based on carbon dioxide for thermochemical energy storage provided by the present invention has the high-temperature turbine and the steam turbine axially connected. By coupling the high-temperature turbine and the steam turbine for power generation, the overall power generation efficiency of the system can be improved. Description of the Drawings

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic diagram of the combined power generation system based on carbon dioxide for thermochemical energy storage provided in the embodiments of the present invention.

[0022] Description of the reference numerals: 1, the first thermochemical reactor; 2, the second thermochemical reactor; 3, the high-temperature turbine; 4, the steam turbine; 5, the first heat exchanger; 6, the second heat exchanger; 7, the water storage tank; 8, the carbon dioxide storage tank. Detailed Embodiments

[0023] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] As Figure 1 shown is a thermochemical energy storage combined power generation system based on carbon dioxide provided in this embodiment, including: a first thermochemical reactor 1 and a high-temperature turbine 3 connected in sequence.

[0028] It further includes: a second thermochemical reactor 2, the inlet ends of the tube layer and the shell layer of which are both communicated with the outlet end of the high-temperature turbine 3; the shell layer of the second thermochemical reactor 2 is communicated with the heat exchange side of a second heat exchanger 6, that is, the heat exchange medium in the second heat exchanger 6 flows between the shell layer of the second chemical reactor and the second heat exchanger 6 to perform heat exchange with the tube layer of the second thermochemical reactor 2. The heat supply side of the second heat exchanger 6 is communicated with both ends of a steam turbine 4, and a water storage tank 7 is connected between the second heat exchanger 6 and the steam turbine 4. The water in the water storage tank 7 is heated into steam and flows between the second heat exchanger 6 and the steam turbine 4 to drive the steam turbine 4 to operate and generate electricity. An auxiliary pump is installed on the water storage tank to drive the steam in the water storage tank to circulate.

[0029] The high-temperature turbine 3 is shaft-connected to the steam turbine 4, and the high-temperature turbine 3 and the steam turbine 4 share a rotating shaft and rotate synchronously to generate electricity synchronously.

[0030] A first heat exchanger 5 is communicated on both sides of the inlet and outlet of the shell layer of the first thermochemical reactor 1. The waste gas of the thermal power plant with waste heat is introduced into the first heat exchanger 5. After heating the heat exchange medium in the first heat exchanger 5, the heat exchange medium is used to heat up the first thermochemical reactor 1 to facilitate the control of the temperature in the first thermochemical reactor 1.

[0031] The outlet end of the tube layer of the second thermochemical reactor 2 is communicated with the inlet end of the tube layer of the first thermochemical reactor 1. A pressure regulating device is installed at the outlet end of the carbon dioxide storage tank 8. The pure carbon dioxide output by the second thermochemical reactor 2 is returned to the inlet of the first thermochemical reactor 1 to react with the oxide in the first thermochemical reactor 1. Together with the pressure regulating device at the outlet end of the carbon dioxide storage tank 8, the gas pressure inside the first thermochemical reactor 1 is controlled, so that the first thermochemical reactor 1 can fully absorb carbon dioxide.

[0032] The first thermochemical reactor 1 is filled with a carbon dioxide reversible release material, and the second thermochemical reactor 2 is filled with a carbon dioxide reversible absorption material. The carbon dioxide reversible release material is one or more of carbonates such as CaCO3, BaCO3, SrCO3, Li2CO3, etc., or can also be one or more of carbon dioxide pore absorption and release materials such as perovskite oxides. The carbon dioxide reversible absorption material is one or more of oxides such as CaO, MgO, ZnO, PbO that can absorb carbon dioxide, or can also be one or more of carbon dioxide pore absorption and release materials such as perovskite oxides and zeolites.

[0033] As Figure 1 shown, the energy storage and combined power generation functions of the system are realized through the following steps: First, during the energy storage process, the waste heat resources of the thermal power plant or the solar heat source are transmitted to the first thermochemical reactor 1 through the first heat exchanger 5. The first thermochemical reactor 1 has a packed bed reaction structure, and a carbonate endothermic decomposition reaction occurs. The generated solid-phase oxide remains in the packed bed layer, and the generated high-temperature carbon dioxide directly drives the high-temperature turbine to generate electricity. At this time, the valve between the high-temperature turbine 3 and the inlet end of the shell layer of the second thermochemical reactor 2 is closed, and the valve between the high-temperature turbine 3 and the inlet end of the tube layer of the second thermochemical reactor 2 is opened. The carbon dioxide at the outlet of the high-temperature turbine 3 enters the tube layer of the second thermochemical reactor 2 and reacts with the oxide in the second thermochemical reactor 2 to generate carbonate by an exothermic reaction. The second thermochemical reactor 2 preferably has a packed bed reaction structure, and the generated carbonate remains in the packed bed layer. The generated heat is connected to the steam turbine through the second heat exchanger 6 to generate electricity again.

[0034] The energy release process of the combined power generation system for thermochemical energy storage based on carbon dioxide is achieved through the following steps: The waste gas source of the thermal power plant containing low partial pressure carbon dioxide to be captured is directly introduced into the tube layer of the first thermochemical reactor 1, where a high-temperature carbonation exothermic reaction occurs. The generated solid carbonate remains in the packed bed layer of the first thermochemical reactor 1, and the decarbonized gas directly drives the high-temperature turbine 3 to generate electricity. At this time, the valve between the high-temperature turbine 3 and the inlet end of the tube layer of the second thermochemical reactor 2 is closed, and the valve between the high-temperature turbine 3 and the inlet end of the shell layer of the second thermochemical reactor 2 is opened. The waste gas after removing carbon dioxide enters the shell layer of the second thermochemical reactor 2 through the gas outlet of the high-temperature turbine 3, and promotes an endothermic decomposition reaction to occur in the second thermochemical reactor 2. The high partial pressure carbon dioxide generated in the tube layer of the second thermochemical reactor enters the first thermochemical reactor 1 again through the carbon dioxide storage tank 8 and the pressure regulating device, realizing the quality improvement of the chemical reaction heat pump and enhancing the energy release efficiency. When the substances inside the first thermochemical reactor 1 and the second thermochemical reactor return to the initial state, the excess carbon dioxide is stored, and the energy release process ends.

[0035] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A thermochemical energy storage combined power generation system based on carbon dioxide, characterized in that, Comprising: A first thermochemical reactor (1) and a high-temperature turbine (3) connected in sequence, and both sides of the inlet and outlet of the shell layer of the first thermochemical reactor (1) are communicated with a first heat exchanger (5); It further comprises: a second thermochemical reactor (2), the inlet end of its tube layer and the inlet end of its shell layer are both communicated with the outlet end of the high-temperature turbine (3); The first thermochemical reactor (1) is filled with a carbon dioxide reversible release material, and the carbon dioxide reversible release material is one or more of BaCO3, SrCO3, Li2CO3, CaCO3, perovskite oxides, and the second thermochemical reactor (2) is filled with a carbon dioxide reversible absorption material; A second heat exchanger (6), its heat exchange side is communicated with the shell layer of the second thermochemical reactor (2) to perform heat exchange with the tube layer of the second thermochemical reactor (2), and its heat supply side is communicated with both ends of a steam turbine (4), and a water storage tank (7) is connected between the second heat exchanger (6) and the steam turbine (4).

2. The combined power generation system for thermochemical energy storage based on carbon dioxide according to claim 1, wherein The high-temperature turbine (3) is shaft-connected to the steam turbine (4).

3. The combined power generation system for thermochemical energy storage based on carbon dioxide according to claim 1 or 2, characterized in that, The inlet end of the tube layer of the first thermochemical reactor (1) is further connected to a carbon dioxide storage tank (8), and the outlet end of the tube layer of the second thermochemical reactor (2) is communicated between the first thermochemical reactor (1) and the carbon dioxide storage tank (8).

4. The combined power generation system for thermochemical energy storage based on carbon dioxide according to claim 1 or 2, characterized in that, The carbon dioxide reversible absorption material is one or more of CaO, MgO, ZnO, PbO, perovskite oxides, and zeolites.

5. The carbon dioxide-based thermochemical energy storage combined power generation system according to claim 3, wherein A pressure regulating device is installed at the outlet end of the carbon dioxide storage tank (8).

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