A dual-stage energy storage power generation system and method based on magnesium reduction of carbon dioxide

Abstract

The present invention discloses a two-stage energy storage power generation system and method based on magnesium reduction of carbon dioxide, wherein the outlet of a magnesium-carbon separation subsystem and the O2 outlet of an air separation device are connected to the inlet of a carbon / O2 burner, the outlet of the carbon / O2 burner is connected to the first boiler in a dual-combustion boiler turbine generator set, and the CO2 outlet of the first boiler is connected to a CO2 compression storage device; the outlet of the CO2 compression storage device and the outlet of the magnesium reduction subsystem are connected to the magnesium / CO2 burner; the magnesium / CO2 burner is connected to the second boiler in the dual-combustion boiler turbine generator set, and the MgO and C discharge outlets of the second boiler are connected to the magnesium-carbon separation subsystem; the power generation output end of the dual-combustion boiler turbine generator set is connected to an external power grid, and the hydrochloric acid preparation subsystem is connected to the magnesium-carbon separation subsystem and the magnesium reduction subsystem. The system and method can meet the power grid demand in extreme climates when no coal is available.

Description

Technical Field

[0001] The present invention belongs to the technical field of safe, zero-emission power generation, and relates to a two-stage energy storage power generation system and method based on magnesium reduction of carbon dioxide. Background Art

[0002] Since wind power and photovoltaic power generation are intermittent, random and volatile, they pose a huge challenge to the safety and reliability of the power system. Especially under extreme weather conditions, wind power and photovoltaic power generation are blocked and energy storage power stations are unavailable, and the power supply will face a huge crisis.

[0003] As far as current technology is concerned, due to cost constraints, the role of energy storage technology in wind and solar power generation on the power supply side is currently limited to eliminating small and short-term power fluctuations. It is impossible to adjust power supply according to grid demand in the short term. When there is no coal available, it is even more unable to cope with power crises in extreme climates. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a two-stage energy storage power generation system and method based on magnesium reduction of carbon dioxide, which can meet the power grid demand in extreme climates when no coal is available.

[0005] To achieve the above-mentioned purpose, the two-stage energy storage and power generation system based on magnesium reduction of carbon dioxide described in the present invention includes a power generation subsystem, a magnesium-carbon separation subsystem, a magnesium reduction subsystem and a hydrochloric acid preparation subsystem;

[0006] The power generation subsystem includes a dual combustion boiler turbine generator set, a carbon / O2 burner, a magnesium / CO2 burner, an air separation unit and a CO2 compression storage device;

[0007] The outlet of the magnesium-carbon separation subsystem and the O2 outlet of the air separation unit are connected to the inlet of the carbon / O2 burner, the outlet of the carbon / O2 burner is connected to the first boiler in the dual-combustion boiler turbine generator set, and the CO2 outlet of the first boiler is connected to the CO2 compression storage device;

[0008] The outlet of the CO2 compression storage device and the outlet of the magnesium reduction subsystem are connected to the magnesium / CO2 burner; the magnesium / CO2 burner is connected to the second boiler in the dual-combustion boiler turbine generator set, and the MgO and C discharge outlets of the second boiler are connected to the magnesium-carbon separation subsystem;

[0009] The power generation output end of the dual-combustion boiler turbine generator set is connected to the external power grid, and the hydrochloric acid preparation subsystem is connected to the magnesium-carbon separation subsystem and the magnesium reduction subsystem.

[0010] The magnesium-carbon separation subsystem includes a MgCl2 generation and separation device, a carbon storage field and a MgCl2 storage tank;

[0011] The input end of the MgCl2 generation and separation device is connected with the MgO and C discharge outlets of the second boiler and the hydrochloric acid preparation subsystem, the MgCl2 outlet of the MgCl2 generation and separation device is connected with the inlet of the MgCl2 storage tank, the outlet of the MgCl2 storage tank is connected with the magnesium reduction subsystem, the C outlet of the MgCl2 generation and separation device is connected with the inlet of the carbon storage field, the H2O outlet of the MgCl2 generation and separation device is connected with the hydrochloric acid preparation subsystem, and the outlet of the carbon storage field is connected with the inlet of the carbon / O2 burner.

[0012] The magnesium reduction subsystem includes a magnesium electrolysis device and a Mg storage tank;

[0013] The inlet of the electrolytic magnesium device is connected to the outlet of the MgCl2 storage tank, the Cl2 outlet of the electrolytic magnesium device is connected to the hydrochloric acid preparation subsystem, the Mg outlet of the electrolytic magnesium device is connected to the inlet of the Mg storage tank, and the outlet of the Mg storage tank is connected to the inlet of the magnesium / CO2 burner.

[0014] The salt preparation subsystem includes a hydrochloric acid generation device and a hydrochloric acid storage tank;

[0015] The Cl2 outlet of the electrolytic magnesium device and the H2O outlet of the MgCl2 generation and separation device are connected to the inlet of the hydrochloric acid generation device, and the outlet of the hydrochloric acid generation device is connected to the inlet of the hydrochloric acid storage tank; the outlet of the hydrochloric acid storage tank is connected to the inlet of the MgCl2 generation and separation device.

[0016] The carbon / O2 burner and the magnesium / CO2 burner are put into operation in different time periods or simultaneously.

[0017] The CO2 compression storage device is provided with an interface for receiving external CO2.

[0018] The dual-stage energy storage and power generation method based on magnesium reduction of carbon dioxide described in the present invention comprises:

[0019] When there is surplus renewable energy power supply, the MgCl2 in the MgCl2 storage tank is sent to the electrolytic magnesium device, and the surplus renewable energy power supply is used to electrolyze Mg and Cl2. The reaction process transfers the electrical energy to Mg to form a primary energy storage, and the generated Mg is sent to the Mg storage tank for storage to form a primary energy storage. The generated Cl2 is sent to the hydrochloric acid generation device, and the dilute hydrochloric acid generated by the hydrochloric acid generation device is sent to the hydrochloric acid storage tank for storage; when the Mg reserves reach the preset reserves, the magnesium / CO2 burner is put into operation for an exothermic reaction, and a part of the energy stored in Mg is output to the second boiler, and the other part is transferred to C to form a secondary energy storage;

[0020] In non-extreme climate conditions, only the Mg / CO2 burner is put into operation, and the dual-combustion boiler turbine generator set operates at a lower load. When the power generation subsystem is in operation, it outputs electric energy to the external power grid to consume the CO2 stored in the CO2 compression storage device. In this process, the MgO and C produced and the hydrochloric acid output from the hydrochloric acid storage tank are sent to the MgCl2 generation and separation device in proportion and separated by water. Among them, the separated C is sent to the carbon storage field for storage, the separated MgCl2 is sent to the MgCl2 storage tank for buffering, and the generated H2O is sent to the hydrochloric acid generation device;

[0021] When the entire network is unable to provide stable power supply due to a long-term lack of wind and light, the O2 output by the air separation unit and the C output by the carbon storage field are sent to the carbon / O2 burner for exothermic reaction. The dual-combustion boiler turbine generator set operates under high load conditions, and the CO2 produced by the carbon / O2 burner is sent back to the CO2 compression storage device for recycling.

[0022] The present invention has the following beneficial effects:

[0023] The two-stage energy storage and power generation system and method based on magnesium reduction of carbon dioxide described in the present invention forms a closed cycle with a fixed order (Mg→MgO→MgCl2→Mg) in the form of a single substance or a compound during specific operation, and there is no consumption of magnesium in the production process; in addition, the first-level Mg energy storage in the two-stage energy storage meets the short-term stable power supply of the power grid, and the second-level C energy storage can be stored indefinitely and in unlimited quantities to ensure the safety of power supply under extreme climatic conditions, and then meet the power grid needs in extreme climates when no coal is available; in addition, since the system consumes CO2 during operation, it can eliminate a large amount of CO2 sealed during the implementation of the "dual carbon" goals, alleviating or eliminating the risk of its leakage to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the present invention.

[0025] Among them, 1 is a dual-combustion boiler turbine generator set, 2 is a power generation output end, 3 is a carbon / O2 burner, 4 is a magnesium / CO2 burner, 5 is a MgO, C discharge outlet, 6 is a CO2 outlet, 7 is an air separation device, 8 is a CO2 compression storage device, 9 is a MgCl2 generation and separation device, 10 is a MgCl2 storage tank, 11 is an electrolytic magnesium device, 12 is a Mg storage tank, 13 is a carbon storage field, 14 is a hydrochloric acid generation device, and 15 is a hydrochloric acid storage tank. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0027] The accompanying drawings show schematic diagrams of structures according to embodiments disclosed in the present invention. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0028] refer to Figure 1 The dual-stage energy storage and power generation system based on magnesium reduction of carbon dioxide described in the present invention includes a power generation subsystem, a magnesium-carbon separation subsystem, a magnesium reduction subsystem and a hydrochloric acid preparation subsystem;

[0029] The power generation subsystem includes a dual-combustion boiler turbine generator set 1, a carbon / O2 burner 3, a magnesium / CO2 burner 4, an air separation device 7 and a CO2 compression storage device 8; the outlet of the magnesium-carbon separation subsystem and the O2 outlet of the air separation device 7 are connected to the inlet of the carbon / O2 burner 3, the outlet of the carbon / O2 burner 3 is connected to the first boiler in the dual-combustion boiler turbine generator set 1, and the CO2 outlet 6 of the first boiler is connected to the CO2 compression storage device 8; the CO2 compression storage device 8 is provided with an interface for receiving external CO2, and the outlet of the CO2 compression storage device 8 and the magnesium reduction subsystem are connected to the magnesium / CO2 burner 4; the magnesium / CO2 burner 4 is connected to the second boiler in the dual-combustion boiler turbine generator set 1, and the MgO and C discharge outlets 5 of the second boiler are connected to the magnesium-carbon separation subsystem; the carbon / O2 burner 3 and the magnesium / CO2 burner 4 can be put into operation in time division or simultaneously, and the power generation output end 2 of the dual-combustion boiler turbine generator set 1 is connected to the external power grid;

[0030] The magnesium-carbon separation subsystem includes a MgCl2 generation and separation device 9, a carbon storage field 13 and a MgCl2 storage tank 10; the input end of the MgCl2 generation and separation device 9 is connected to the MgO, C discharge port 5 of the second boiler and the hydrochloric acid preparation subsystem, the MgCl2 outlet of the MgCl2 generation and separation device 9 is connected to the inlet of the MgCl2 storage tank 10, the outlet of the MgCl2 storage tank 10 is connected to the magnesium reduction subsystem, the C outlet of the MgCl2 generation and separation device 9 is connected to the inlet of the carbon storage field 13, the H2O outlet of the MgCl2 generation and separation device 9 is connected to the hydrochloric acid preparation subsystem, and the outlet of the carbon storage field 13 is connected to the inlet of the carbon / O2 burner 3.

[0031] The magnesium reduction subsystem includes an electrolytic magnesium device 11 and a Mg storage tank 12; the inlet of the electrolytic magnesium device 11 is connected to the outlet of the MgCl2 storage tank 10, the Cl2 outlet of the electrolytic magnesium device 11 is connected to the hydrochloric acid preparation subsystem, the Mg outlet of the electrolytic magnesium device 11 is connected to the inlet of the Mg storage tank 12, and the outlet of the Mg storage tank 12 is connected to the inlet of the magnesium / CO2 burner 4.

[0032] The salt preparation subsystem includes a hydrochloric acid generating device 14 and a hydrochloric acid storage tank 15; the Cl2 outlet of the electrolytic magnesium device 11 and the H2O outlet of the MgCl2 generating and separating device 9 are connected to the inlet of the hydrochloric acid generating device 14, and the outlet of the hydrochloric acid generating device 14 is connected to the inlet of the hydrochloric acid storage tank 15; the outlet of the hydrochloric acid storage tank 15 is connected to the inlet of the MgCl2 generating and separating device 9; Cl2 and H2O react in the hydrochloric acid generating device 14 to generate hydrochloric acid, which is sent to the hydrochloric acid storage tank 15.

[0033] The dual-stage energy storage and power generation method based on magnesium reduction of carbon dioxide described in the present invention comprises:

[0034] When there is surplus renewable energy power supply, the MgCl2 in the MgCl2 storage tank 10 is sent to the electrolytic magnesium device 11, and the surplus renewable energy power supply is used for electrolysis to generate Mg and Cl2. The reaction process transfers the electric energy to Mg to form a primary energy storage, and the generated Mg is sent to the Mg storage tank 12 for storage to form a primary energy storage, and the generated Cl2 is sent to the hydrochloric acid generation device 14, and the dilute hydrochloric acid generated by the hydrochloric acid generation device 14 is sent to the hydrochloric acid storage tank 15 for storage, wherein the design reserves of the Mg storage tank 12 and the MgCl2 storage tank 10 are calculated and determined based on the total electric energy that needs to be consumed within the design days of the primary energy storage; when the Mg reserves reach the preset reserves, the magnesium / CO2 burner 4 is put into operation, and its reaction is an exothermic reaction: 2Mg+CO2=2MgO+C, and the reaction process outputs part of the energy stored in Mg to the second boiler in the form of reaction heat, and the other part is transferred to C to form a secondary energy storage;

[0035] In non-extreme climate conditions, the dual-combustion boiler turbine generator set 1 only operates the Mg / CO2 burner, and the unit operates at a relatively low load. When the power generation subsystem is in operation, it flexibly outputs electric energy to the grid, and consumes the CO2 stored in the CO2 compression storage device 8. When the CO2 reserves in the CO2 compression storage device 8 are small, it is supplemented from the outside. In this process, the MgO and C produced and the hydrochloric acid output from the hydrochloric acid storage tank 15 are proportionally sent to the MgCl2 generation and separation device 9. Since MgCl2 dissolves in water, while C does not dissolve in water, the separation of MgCl2 and C is achieved. The separated C is sent to the carbon storage field 13 for storage, the separated MgCl2 is sent to the MgCl2 storage tank 10 for short-term buffering, and the generated H2O is sent to the hydrochloric acid generation device 14 for use in preparing hydrochloric acid.

[0036] When the entire network is short of wind and light for a long time, causing the power grid to be unable to supply stable power, the O2 output by the air separation unit 7 and the C output by the carbon storage field 13 are sent to the carbon / O2 burner 3 for an exothermic reaction. The reaction formula is: C+O2=CO2, and the dual-combustion boiler turbine generator set 1 operates under high load conditions; the CO2 generated by the carbon / O2 burner 3 is sent back to the CO2 compression storage device 8 for recycling.

Claims

1. A two-stage energy storage and power generation system based on magnesium reduction of carbon dioxide, characterized in that: It includes a power generation subsystem, a magnesium-carbon separation subsystem, a magnesium reduction subsystem and a hydrochloric acid preparation subsystem; The power generation subsystem comprises a dual combustion boiler turbine generator set (1), a carbon / O2 burner (3), a magnesium / CO2 burner (4), an air separation device (7) and a CO2 compression storage device (8); The outlet of the magnesium-carbon separation subsystem and the O2 outlet of the air separation unit (7) are connected to the inlet of the carbon / O2 burner (3), the outlet of the carbon / O2 burner (3) is connected to the first boiler in the dual-combustion boiler turbine generator set (1), and the CO2 outlet (6) of the first boiler is connected to the CO2 compression storage device (8); The outlet of the CO2 compression storage device (8) and the outlet of the magnesium reduction subsystem are connected to the magnesium / CO2 burner (4); the magnesium / CO2 burner (4) is connected to the second boiler in the dual-combustion boiler turbine generator set (1); and the MgO and C discharge outlet (5) of the second boiler is connected to the magnesium-carbon separation subsystem; The power output end (2) of the dual combustion boiler turbine generator set (1) is connected to an external power grid, and the hydrochloric acid preparation subsystem is connected to the magnesium-carbon separation subsystem and the magnesium reduction subsystem; The carbon / O2 burner (3) and the magnesium / CO2 burner (4) are put into operation in different time periods or simultaneously; The CO2 compression storage device (8) is provided with an interface for receiving external CO2; The magnesium-carbon separation subsystem comprises a MgCl2 generation and separation device (9), a carbon storage field (13) and a MgCl2 storage tank (10); The input end of the MgCl2 generation and separation device (9) is connected to the MgO and C discharge outlet (5) of the second boiler and the hydrochloric acid preparation subsystem, the MgCl2 outlet of the MgCl2 generation and separation device (9) is connected to the inlet of the MgCl2 storage tank (10), the outlet of the MgCl2 storage tank (10) is connected to the magnesium reduction subsystem, the C outlet of the MgCl2 generation and separation device (9) is connected to the inlet of the carbon storage field (13), the H2O outlet of the MgCl2 generation and separation device (9) is connected to the hydrochloric acid preparation subsystem, and the outlet of the carbon storage field (13) is connected to the inlet of the carbon / O2 burner (3); The magnesium reduction subsystem comprises a magnesium electrolysis device (11) and a Mg storage tank (12); The inlet of the electrolytic magnesium device (11) is connected to the outlet of the MgCl2 storage tank (10), the Cl2 outlet of the electrolytic magnesium device (11) is connected to the hydrochloric acid preparation subsystem, the Mg outlet of the electrolytic magnesium device (11) is connected to the inlet of the Mg storage tank (12), and the outlet of the Mg storage tank (12) is connected to the inlet of the magnesium / CO2 burner (4).

2. The dual-stage energy storage and power generation system based on magnesium reduction of carbon dioxide according to claim 1 is characterized in that: The hydrochloric acid preparation subsystem comprises a hydrochloric acid generating device (14) and a hydrochloric acid storage tank (15); The Cl2 outlet of the electrolytic magnesium device (11) and the H2O outlet of the MgCl2 generating and separating device (9) are connected to the inlet of the hydrochloric acid generating device (14); the outlet of the hydrochloric acid generating device (14) is connected to the inlet of the hydrochloric acid storage tank (15); and the outlet of the hydrochloric acid storage tank (15) is connected to the inlet of the MgCl2 generating and separating device (9).

3. A two-stage energy storage and power generation method based on magnesium reduction of carbon dioxide, characterized in that: The dual-stage energy storage and power generation system based on magnesium reduction of carbon dioxide according to claim 2 comprises: When there is surplus renewable energy power supply, the MgCl2 in the MgCl2 storage tank (10) is fed into the electrolytic magnesium device (11), and the surplus renewable energy power supply is used to electrolyze and generate Mg and Cl2. The reaction process transfers the electrical energy to Mg to form primary energy storage. The generated Mg is fed into the Mg storage tank (12) for storage to form primary energy storage. The generated Cl2 is fed into the hydrochloric acid generation device (14), and the dilute hydrochloric acid generated by the hydrochloric acid generation device (14) is fed into the hydrochloric acid storage tank (15) for storage. When the Mg reserve reaches a preset reserve, the magnesium / CO2 burner (4) is put into operation to perform an exothermic reaction, and a part of the energy stored in Mg is output to the second boiler, and the other part is transferred to C to form secondary energy storage. When the climatic conditions are not extreme, only the Mg / CO2 burner is put into operation, and the dual-combustion boiler turbine generator set (1) operates at a relatively low load. When the power generation subsystem is in operation, it outputs electric energy to the external power grid to consume the CO2 stored in the CO2 compression storage device (8). In this process, the MgO and C generated and the hydrochloric acid output from the hydrochloric acid storage tank (15) are sent to the MgCl2 generation and separation device (9) in proportion and separated by water. The separated C is sent to the carbon storage field (13) for storage, the separated MgCl2 is sent to the MgCl2 storage tank (10) for buffering, and the generated H2O is sent to the hydrochloric acid generation device (14); When the entire network is short of wind and light for a long time, causing the power grid to be unable to supply stable power, the O2 output from the air separation unit (7) and the C output from the carbon storage field (13) are sent to the carbon / O2 burner (3) for exothermic reaction, and the dual-combustion boiler turbine generator set (1) operates under high load conditions. The CO2 generated by the operation of the carbon / O2 burner (3) is sent back to the CO2 compression storage device (8) for recycling.

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