Thermal power carbon capture and energy storage integrated system based on calcium cycle coupling chemical looping combustion technology

Abstract

The invention provides a thermal power carbon capture and energy storage integrated system based on a calcium cycle coupling chemical looping combustion technology, and belongs to the field of thermal chemical energy storage and CO2 capture. The system comprises an energy release / CO2 absorption unit and an energy storage / CO2 release unit, and integration of CO2 capture and energy storage can be realized at the same time. The energy release / CO2 absorption unit comprises a compressor, a mixer, a carbonation / oxidation reactor, an expansion machine and a steam preheater which are connected in sequence; the energy storage / CO2 release unit comprises a calcination / reduction reactor and a Rankine cycle part connected with the calcination / reduction reactor; in the system, CaO / MeOx-1 is converted into CaCO3 / MeOx through carbonation / oxidation reaction, CaCO3 / MeOx is converted into CaO / MeOx-1 through calcination / reduction reaction, and circulation is formed. The invention solves the problem of low power generation efficiency in the energy release process due to the temperature of superheated steam lower than 650 DEG C because the existing calcium-based CO2 capture / energy storage integrated system releases energy in the form of generating power through heat recovery and steam production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thermo-chemical energy storage and CO2 capture, and in particular to a thermal power carbon capture and energy storage integrated system based on calcium cycle coupled with chemical looping combustion technology. BACKGROUND

[0002] Carbon capture is one of the core technologies to address global climate change and achieve carbon neutrality. It is the first step in the carbon capture, utilization and storage (CCUS) technology system. The core goal of this field is to capture carbon dioxide from industrial emissions or the atmosphere and utilize or permanently store it. According to the separation timing and principle of carbon dioxide, the mainstream carbon capture technology can be divided into three categories: (1) post-combustion capture, which separates CO2 from flue gas generated after fuel combustion, and the mainstream technology is chemical absorption, such as organic amine solution absorption; (2) pre-combustion capture, which converts fuel into syngas (mainly H2 and CO2) before combustion, and then separates high-concentration CO2; (3) oxygen-enriched combustion, which uses high-purity oxygen instead of air to assist combustion, so that the combustion products are mainly CO2 and water vapor, thereby obtaining high-concentration and easily captured CO2.

[0003] In the field of carbon capture, thermo-chemical energy storage is a key supporting technology, and its core goal is to solve the high energy consumption problem in the carbon capture process and improve the economic and feasibility of the entire system. Thermo-chemical energy storage is a technology that uses reversible chemical reactions to store and release heat energy, like a high-efficiency "heat energy battery", which can flexibly store and allocate the heat energy required in the capture link. Calcium-based CO2 capture / energy storage integrated system is the most typical frontier technology in the field of carbon capture and thermo-chemical energy storage. This system uses the reversible chemical reaction of "calcium oxide / calcium carbonate" to simultaneously complete the two core tasks of capturing carbon dioxide from flue gas and storing heat energy in the same cycle.

[0004] The system contains two opposite chemical reactions, forming a closed cycle: First, carbon capture and heat storage (exothermic process): This step is carried out at a moderate temperature (about 600-700°C), and the system uses calcium oxide to capture carbon dioxide from industrial flue gas while releasing heat energy. The reaction equation is as follows: CaO (solid) + CO2 (gas) → CaCO3 (solid) + heat (Formula 1) This step is a carbonation reaction, in which calcium oxide combines with carbon dioxide to form calcium carbonate. This reaction releases a large amount of heat, which can be recovered for power generation or heating, achieving the output of chemical energy storage.

[0005] Second step, CO2 release and charging (endothermic process): This step is carried out at high temperature (about 850-950℃), the system releases the stored carbon dioxide, while needing to absorb a large amount of heat energy from the outside, the reaction equation is as follows: CaCO3 (solid) + heat → CaO (solid) + CO2 (gas) (Formula 2) This step is a calcination (or decomposition) reaction, calcium carbonate absorbs heat at high temperature, decomposes into high-purity carbon dioxide gas and regenerated calcium oxide. The absorbed heat energy (which can come from green electricity, waste heat, etc.) is converted into chemical energy stored in regenerated CaO, completing the energy input and storage of the system.

[0006] The raw material used by the calcium-based CO2 capture / energy storage integrated system is calcium oxide / calcium carbonate (such as limestone), which has extremely abundant reserves, low cost, and is non-toxic and harmless, avoiding the degradation, volatilization and potential pollution problems of traditional amine capture organic amine solvents. The system combines capture and energy storage into one, reducing the complexity and equipment investment of separate systems, and is particularly suitable for combination with high-emission industrial scenes such as coal-fired power plants, cement plants and steel plants, and has broad prospects.

[0007] However, the existing calcium-based CO2 capture / energy storage integrated system usually releases energy in the form of heat recovery to produce steam for power generation, and the temperature of the superheated steam is lower than 560℃. In thermal power generation, the temperature and pressure of the steam directly determine the thermal cycle efficiency (Carnot efficiency), and the power generation system driven by the medium-temperature steam generated by the system has limited power generation efficiency due to the temperature difference between the carbonation reactor temperature and the heat exchange temperature, and it is difficult to further improve the power generation efficiency. At the same time, when recovering the carbonation process energy to produce superheated steam, due to the large difference between the high-pressure steam phase change temperature (370℃) and the carbonation heat temperature (650℃), the carbonation heat recovery process has a large function loss, resulting in low power generation efficiency in the energy release process. SUMMARY

[0008] In view of the above problems existing in the prior art, the present application provides a thermal power carbon capture and energy storage integrated system based on calcium cycle coupled with chemical looping combustion technology. The present application solves the problem of low power generation efficiency in the energy release process caused by the temperature of the superheated steam being lower than 650℃ in the existing calcium-based CO2 capture / energy storage integrated system which releases energy in the form of heat recovery to produce steam for power generation.

[0009] The technical scheme of the present application is as follows: A thermal power carbon capture and energy storage integrated system based on calcium cycle coupled with chemical looping combustion technology, the system includes an energy release / CO2 absorption unit and an energy storage / CO2 release unit, and simultaneously realizes CO2 capture and energy storage integration; The CO2 release / absorption unit includes a compressor, a mixer, a carbonation / oxidation reactor, an expander, and a steam preheater connected in sequence; the steam outlet of the steam preheater is connected to the mixer; the carbonation / oxidation reactor is also connected to CaCO3 / MeO2. x Storage tanks and CaO / MeO x-1 Storage tanks; The CO2 storage / release unit includes a calcination / reduction reactor and a Rankine cycle connected thereto; the calcination / reduction reactor is also connected to CaCO3 / MeO2. x Storage tanks and CaO / MeO x-1 Storage tank.

[0010] Furthermore, the compressor in the CO2 release / absorption unit receives externally input industrial flue gas, pressurizes the industrial flue gas, and then delivers it to the mixer. The pressurization pressure range is 4-8 bar. The mixer mixes pressurized industrial flue gas with water vapor from a steam preheater and then delivers it to the carbonation / oxidation reactor. The carbonation / oxidation reaction occurs in the carbonation / oxidation reactor, converting CaO / MeO into carbon dioxide. x-1 CaO / MeO in storage tanks x-1 Converted to CaCO3 / MeO x Transported to CaCO3 / MeO x In the storage tank, high-temperature and high-pressure oxygen- and carbon-deficient air is directly generated to capture carbon dioxide in industrial flue gas. The carbonation / oxidation reaction is carried out at a temperature of 700-850°C and a reaction pressure of 4-8 bar.

[0011] Furthermore, the high-temperature, high-pressure, oxygen- and carbon-deficient air is transported to an expander, where it expands and performs work, then connects to a gas turbine generator to generate electricity, forming a high-temperature Brayton cycle. The resulting exhaust gas heats externally pressurized water in a steam preheater, converting the water into steam, which is then transported to a mixer. The steam mixes with the decarbonized flue gas to obtain wet flue gas, which is then discharged. This wet flue gas is fed into a carbonation / oxidation reactor for a carbonation / oxidation reaction, where CO2 and O2 in the flue gas provide the reaction elements. The steam and nitrogen absorb the heat of the reaction, causing the temperature to rise.

[0012] Preferably, the industrial flue gas includes coal-fired flue gas, natural gas power plant flue gas, or biomass power plant flue gas; the pressure of the external pressurized water is 4-6 bar.

[0013] Preferably, the CaO / MeO x-1 It is a solid adsorbent / oxygen support material, wherein Me includes one or more of Ni, Fe, Co, Mn or Cu, and CaO and MeO x-1The molar ratio of the feed is 6-30:1.

[0014] Further, the calcination / reduction reactor in the energy storage / CO2 release unit receives CaCO3 / MeO x CaCO3 / MeO in the storage tank x , reacts with the external carbon-containing fuel to generate gaseous products CO2 and H2O and solid product CaO / MeO x-1 , the reaction temperature is 850-950℃, the reaction pressure is normal pressure, and the heat required in the reaction process is provided by electric heating.

[0015] Preferably, the solid product CaO / MeO x-1 CaO / MeO is transported back to the storage tank and then recycled to the carbonation / oxidation reactor; x-1 The storage tank, and then recycled to the carbonation / oxidation reactor; The gaseous products CO2 and H2O enter the Rankine cycle part, the heat carried by the gaseous products is recovered by Rankine cycle to generate electricity, and the condensed CO2 and H2O are separated to obtain high-purity CO2.

[0016] Further, the Rankine cycle part includes a waste heat boiler, a steam turbine unit, a steam turbine unit generator, a product condenser, a water pump, and a condenser; The waste heat boiler is connected to the product condenser and the steam turbine unit respectively, the steam turbine unit is connected to the condenser, and the condenser is connected to the waste heat boiler through the water pump; The gaseous products CO2 and H2O are cooled in the waste heat boiler and transported to the product condenser to be separated in the form of gaseous CO2 and liquid H2O; the heat obtained in the waste heat boiler generates high-pressure steam, which is then input into the steam turbine unit to expand and do work, driving the steam turbine unit generator to generate electricity; the exhaust steam at the outlet of the steam turbine unit enters the condenser to be condensed to form condensed water, which is pressurized by the water pump after being cooled and then transported back to the waste heat boiler to absorb heat to obtain high-pressure steam, forming a Rankine cycle.

[0017] Preferably, the carbon-containing fuel includes a mixture of one or more of natural gas, biomass, ammonia, or hydrogen; MeO x The mass ratio to the carbon-containing fuel is 10-30:1; the electric heating can use valley electricity and / or renewable green electricity for heating, so as to convert renewable energy power into chemical energy of solid materials.

[0018] In the system provided by the application, the energy release / CO2 absorption unit is used to realize CO2 capture in the flue gas of a coal-fired power plant, a natural gas power plant, or a biomass power plant and energy release of solid energy storage materials; the energy storage / CO2 release unit converts the energy of solid energy storage materials into electricity and obtains high-purity CO2, so as to realize storage of valley electricity and / or green electricity and CO2 capture.

[0019] The beneficial technical effect of the present application is that: 1. Compared with the method of recovering heat by using the Brayton cycle in the prior art, the present application innovatively generates high-temperature and high-pressure oxygen-poor and carbon-poor air directly in the carbonation / energy release process by flue gas pressurization and coupling of a chemical looping oxidation process, and then recovers the waste heat of the spent air by the Brayton cycle and in the form of preheated water vapor.

[0020] 2. Compared with the method of recovering power generation by using the CO2 Brayton cycle in the prior art, the present application directly uses the carbonation / oxidation reaction heat as a heat source to heat high-pressure flue gas, and the working medium for work is different, the working medium for work of the present application is wet flue gas, and CO2 can be captured and the oxygen medium involved in the flue gas can be fully utilized at the same time of the Brayton cycle.

[0021] 3. The present application fully utilizes the O2 and CO2 components in the flue gas and improves the power generation efficiency in the energy release stage by coupling the chemical looping oxidation process and generating power by the high-temperature Brayton cycle; the air of the coal-fired power plant can be preheated by the spent air after expansion, and the power generation efficiency of the coal-fired power plant can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a structural schematic diagram of a power plant carbon capture and energy storage integrated system of a calcium cycle coupled with a chemical looping combustion technology of the present application; In the figure, 1 is a compressor, 2 is a mixer, 3 is a carbonation / oxidation reactor, 4 is an expander, 41 is a gas turbine generator, 5 is a steam preheater, 6 is a CaCO3 / MeO x storage tank, 7 is a CaO / MeO x-1 storage tank, 8 is a calcination / reduction reactor, 9 is a waste heat boiler, 10 is a steam turbine unit, 11 is a steam turbine unit generator, 12 is a product condenser, 13 is a water pump, and 14 is a condenser.

[0023] Figure 2 FIG. 2 is a structural schematic diagram of a calcium-based energy storage / carbon capture integrated system in a comparative example; In the figure, 15 is a carbonation reactor, 16 is a CaCO3 storage tank, 17 is a CaO storage tank, and 18 is a calcination reactor. DETAILED DESCRIPTION

[0024] The present application will be described in detail below in conjunction with the drawings and examples. Obviously, the described examples are only some of the examples of the present application, but not all the examples. Based on the examples in the present application, all other examples obtained by a person of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0025] The embodiment provides a power plant carbon capture and energy storage integrated system based on calcium cycle coupled chemical looping combustion technology, and the structure is as shown in Figure 1

[0026] The system comprises a CO2 releasing / absorbing unit and an energy storage / CO2 releasing unit, and can realize the integration of CO2 capture and energy storage. The CO2 releasing / absorbing unit comprises a compressor 1, a mixer 2, a carbonation / oxidation reactor 3, an expander 4 and a steam preheater 41 connected in sequence; and the energy storage / CO2 releasing unit comprises a calcination / reduction reactor 8 and a Rankine cycle part connected with the calcination / reduction reactor 8.

[0027] The CO2 releasing / absorbing unit further comprises CaCO3 / MeO x storage tank 6 and CaO / MeO x-1 storage tank 7, and the carbonation / oxidation reactor 3 is connected with the CaCO3 / MeO x storage tank 6 and CaO / MeO x-1 storage tank 7, and the calcination / reduction reactor 8 is also connected with the CaCO3 / MeO x storage tank 6 and CaO / MeO x-1 storage tank 7. The CaCO3 / MeO x storage tank 6 and CaO / MeO x-1 storage tank 7 is cyclically connected between the carbonation / oxidation reactor 3 and the calcination / reduction reactor 8.

[0028] The CaO / MeO x-1 is a solid adsorption / oxygen carrier material, wherein Me comprises one or more of Ni, Fe, Co, Mn or Cu, and the feed molar ratio of CaO to MeO x-1 is 6-30:1.

[0029] The compressor 1 in the CO2 releasing / absorbing unit receives externally input industrial flue gas, and the industrial flue gas is pressurized and then delivered to a pressurized flue gas inlet of the mixer 2, and the pressure range of the pressurization is 4-8 bar; the industrial flue gas comprises coal-fired flue gas, natural gas power plant flue gas or biomass power plant flue gas.

[0030] In the CO2 releasing / absorbing unit, a steam preheater 5 is further included, and a water vapor outlet of the steam preheater 5 is connected with a water vapor inlet of the mixer 2; the steam preheater 5 is heated by low-temperature and low-pressure exhaust gas obtained after turbine work of the expander 4. The industrial flue gas after pressurization is mixed with water vapor from the steam preheater 5 in the mixer 2, and then delivered to the carbonation / oxidation reactor 3.

[0031] The carbonation / oxidation reaction occurs in the carbonation / oxidation reactor 3, and the CaO / MeO x-1 ​CaO / MeO in storage tank 7 x-1 Converted to CaCO3 / MeO x Transported to CaCO3 / MeO x In storage tank 6, high-temperature and high-pressure oxygen- and carbon-deficient air is directly generated to capture carbon dioxide in industrial flue gas. The carbonation / oxidation reaction is carried out at a temperature of 700-850°C and a reaction pressure of 4-8 bar.

[0032] The high-temperature, high-pressure oxygen- and carbon-deficient air is transported to an expander, where it expands and performs work in the turbine and is connected to a gas turbine generator to generate electricity, forming a high-temperature Brayton cycle. The resulting exhaust gas is used in a preheater 5 to heat externally pressurized water, converting the water into water vapor. The pressure of the externally pressurized water is 4-6 bar.

[0033] Most of the resulting water vapor is transported to mixer 2, and the remaining water vapor is mixed with the decarbonized flue gas to obtain wet flue gas for discharge. The wet flue gas is fed into carbonation / oxidation reactor 3 for carbonation / oxidation reaction, in which CO2 and O2 in industrial flue gas provide reaction elements. Water vapor and nitrogen absorb the heat of reaction and heat up, and then enter expander 4 for recycling.

[0034] The calcination / reduction reactor 8 in the energy storage / CO2 release unit receives CO2 from CaCO3 / MeO x CaCO3 / MeO in storage tank 6 x It reacts with external carbon-containing fuels to produce gaseous products CO2 and H2O and solid products CaO / MeO. x-1 The reaction temperature is 850-950℃, the reaction pressure is atmospheric pressure, and the heat required for the reaction process is provided by electric heating. The carbon-containing fuel includes one or more of natural gas, biomass, ammonia, or hydrogen; the electric heating can be carried out using off-peak electricity and / or renewable green electricity, thereby converting renewable energy electricity into the chemical energy of solid materials.

[0035] The solid product CaO / MeO x-1 Transported back to CaO / MeO x-1 The waste is then returned to the carbonation / oxidation reactor 3 for recycling in storage tank 7. The gaseous products CO2 and H2O enter the Rankine cycle section, where the heat they carry is recovered and used to generate electricity. The condensed CO2 is separated from H2O to obtain high-purity CO2. The Rankine cycle section includes a waste heat boiler 9, a steam turbine unit 10, a steam turbine generator 11, a product condenser 12, a water pump 13, and a condenser 14.

[0036] Waste heat boiler 9 is connected to product condenser 12 and turbine unit 10. Turbine unit 10 is connected to condenser 14, and condenser 14 is connected to waste heat boiler 9 via a water pump. The gaseous products CO2 and H2O are cooled in waste heat boiler 9 and transported to product condenser 12, where they are separated as gaseous CO2 and liquid H2O. The heat obtained in waste heat boiler 9 generates high-pressure steam, which is then input into turbine unit 10 to expand and do work, driving turbine generator 11 to generate electricity. The exhaust steam from turbine unit 10 enters condenser 14 and condenses to form condensate. The cooled condensate is pressurized by water pump 13 and transported back to waste heat boiler 9 to absorb heat and obtain high-pressure steam, forming a Rankine cycle.

[0037] In this system, the CO2 release / absorption unit can be used to capture CO2 in the flue gas of coal-fired power plants, natural gas power plants or biomass power plants and release energy from solid energy storage materials; the CO2 storage / release unit converts the energy of solid energy storage materials into electricity and obtains high-purity CO2, thereby realizing the storage of off-peak electricity and / or green electricity and CO2 capture.

[0038] Comparative example: The comparative example uses a traditional calcium-based integrated energy storage / carbon capture system, with a structure as follows: Figure 2 As shown, the solid carriers are CaCO3 / CaO, placed in CaCO3 storage tank 16 and CaO storage tank 17 respectively. These two tanks are connected to carbonation reactor 15 and calcination reactor 18 respectively, forming a circulating connection. Industrial flue gas enters carbonation reactor 15 to undergo carbonation (reaction equation shown in Equation 1), and calcination reaction occurs in calcination reactor 18 (reaction equation shown in Equation 2). The heat of carbonation, the sensible heat of decarbonized flue gas, and the sensible heat of calcination products in both reactions are recovered through a Rankine cycle. The structure of the Rankine cycle is the same as in the embodiment, consisting of waste heat boiler 9, turbine unit 10, turbine generator 11, product condenser 12, water pump 13, and condenser 14.

[0039] Test example: Using flue gas from a 600 MW coal-fired power plant as the target for capture, operational tests were conducted on the two systems in the example and comparative cases, respectively.

[0040] In the comparative system, the adsorbent was CaO / CaCO3, the CaO feed rate was 12.98 kmol / s, the carbonation reactor 15 operated at a temperature of 650℃ and a pressure of atmospheric pressure, and the CO2 capture rate in the flue gas was 90%. The calcination reactor 18 operated at a temperature of 900℃ and a pressure of atmospheric pressure. The exhaust gas temperature of the waste heat boiler 9 was 70℃, and triple reheat was used. The steam parameters and pressures were 566℃ / 566℃ / 305℃ and 126 bar / 26 bar / 5.5 bar, respectively.

[0041] In the system of this embodiment, the selected adsorbent and oxygen carrier are CaO / CaCO3 and Ni / NiO, respectively. The feed molar amounts of CaO and Ni to the carbonation / oxidation reactor are 12.98 kmol / s and 0.83 kmol / s, respectively. The outlet pressure of compressor 1 is 6 bar. The pressure of the external pressurized water introduced into steam preheater 5 is 6 bar. The temperature of the steam fed into mixer 2 from steam preheater 5 is 160-200°C. The exhaust gas temperature of steam preheater 5 is 70°C.

[0042] The carbonation / oxidation reactor 3 operates at a temperature of 750℃ and a pressure of 6 bar, with a CO2 absorption rate of 90% and an O2 absorption rate of 40% in the flue gas. The calcination / reduction reactor 8 operates at a temperature of 900℃ and a pressure of atmospheric pressure, using coal as the selected carbon-containing fuel with a NiO / coal fuel mass ratio of 10:1, and generating green electricity. The waste heat boiler 9 has a flue gas temperature of 70℃, employs triple-pressure reheat, and has steam parameters and pressures of 566℃ / 566℃ / 305℃ and 126 bar / 26 bar / 5.5 bar, respectively.

[0043] CO2 and H2O in calcination / reduction reactor 8 are condensed in product condenser 12 after heat recovery by waste heat boiler 9, yielding CO2 and H2O respectively. In this embodiment, the CO2 flow rate is 129.97 kg / s and the H2O flow rate is 2.76 kg / s. In the comparative system, the condensed product is CO2 with a mass flow rate of 114.28 kg / s.

[0044] The specific operating parameters and results of the two systems, the comparative example and the embodiment, are shown in Table 1 below.

[0045] Table 1 Note: Round trip efficiency = Net power output / (Power input + Fuel energy input); * Negative values ​​indicate power consumption, positive values ​​indicate power output; Net power output = Gas turbine power generation + Steam turbine power generation - Compressor power consumption.

[0046] As can be seen from Table 1, in the embodiment of the present invention, the heat generated by the carbonation / oxidation reactor 3 is released through a high-temperature Brayton cycle, and the total output power of the expander 4 and compressor 1 is 317.0 MW. In the comparative example, the heat generated by the carbonation reactor 15 is recovered in the waste heat boiler 9 to produce high-temperature steam, and then does work through a Rankine cycle.

[0047] Due to the different heat recovery method of the carbonation reactor 15, the power generation of the turbine unit 10 of the waste heat boiler 9 in this embodiment of the invention is 183.7 MW less than that in the comparative example (accounting for 27.7% of the energy input), but the output power through the high-temperature Brayton cycle is 317.0 MW (accounting for 39.9% of the energy input). This shows that the method proposed in this invention can have a higher power generation efficiency than the traditional energy release process power generation method.

[0048] The comparison shows that, on the one hand, the present invention increases the partial pressure of CO2 and oxygen in the carbonation / oxidation process by pressurizing the flue gas, allowing the carbonation / oxidation reactor 3 to operate at a higher temperature, thus increasing the heat source temperature; on the other hand, the high-temperature Brayton cycle directly heats the flue gas inside the carbonation / oxidation reactor 3, eliminating the heat exchange temperature difference. Compared to the Rankine cycle which uses steam as the working fluid, the flue gas exiting the carbonation / oxidation reactor 3 directly enters the expander 4, and the inlet temperature of the expander 4 is higher than the inlet temperature of the turbine unit 11. Therefore, the system proposed in this invention has a higher power generation efficiency in the energy release stage, and the overall round-trip efficiency is increased from 34.9% to 45.9% compared to the comparative example.

[0049] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, and for those of ordinary skill in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. Therefore, the present invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims

1. An integrated carbon capture and energy storage system for thermal power plants based on calcium cycle coupled chemical looping combustion technology, characterized in that, The system comprises two parts: an energy release / absorption CO2 unit and an energy storage / release CO2 unit, thus achieving integrated CO2 capture and energy storage. The CO2 release / absorption unit includes a compressor, a mixer, a carbonation / oxidation reactor, an expander, and a steam preheater connected in sequence; the steam outlet of the steam preheater is connected to the mixer; the carbonation / oxidation reactor is also connected to CaCO3 / MeO2. x Storage tanks and CaO / MeO x-1 Storage tanks; The CO2 storage / release unit includes a calcination / reduction reactor and a Rankine cycle connected thereto; the calcination / reduction reactor is also connected to CaCO3 / MeO2. x Storage tanks and CaO / MeO x-1 Storage tank.

2. The system according to claim 1, characterized in that, The compressor in the CO2 release / absorption unit receives externally input industrial flue gas, pressurizes the industrial flue gas, and then delivers it to the mixer. The pressurization pressure range is 4-8 bar. The mixer mixes pressurized industrial flue gas with water vapor from a steam preheater and then delivers it to the carbonation / oxidation reactor. The carbonation / oxidation reaction occurs in the carbonation / oxidation reactor, converting CaO / MeO into carbon dioxide. x-1 CaO / MeO in storage tanks x-1 Converted to CaCO3 / MeO x Transported to CaCO3 / MeO x In the storage tank, high-temperature and high-pressure oxygen- and carbon-deficient air is directly generated to capture carbon dioxide in industrial flue gas. The carbonation / oxidation reaction is carried out at a temperature of 700-850°C and a reaction pressure of 4-8 bar.

3. The system according to claim 2, characterized in that, The high-temperature, high-pressure, oxygen- and carbon-deficient air is transported to an expander, where it expands and performs work, then connects to a gas turbine generator to generate electricity, forming a high-temperature Brayton cycle. The resulting exhaust gas heats external pressurized water in a steam preheater, converting the water into steam, which is then transported to a mixer. The steam and decarbonized flue gas are mixed to produce wet flue gas, which is then discharged. The wet flue gas is then fed into a carbonation / oxidation reactor for a carbonation / oxidation reaction, where CO2 and O2 in the flue gas provide the reaction elements. The steam and nitrogen absorb the heat of the reaction and increase the temperature.

4. The system according to claim 3, characterized in that, The industrial flue gas includes coal-fired flue gas, natural gas power plant flue gas, or biomass power plant flue gas; the pressure of the external pressurized water is 4-6 bar.

5. The system according to claim 3, characterized in that, The CaO / MeO x-1 It is a solid adsorbent / oxygen support material, wherein Me includes one or more of Ni, Fe, Co, Mn or Cu, and CaO and MeO x-1 The feed molar ratio is 6-30:

1.

6. The system according to claim 1, characterized in that, The calcination / reduction reactor in the energy storage / CO2 release unit receives CO2 / MeO2. x CaCO3 / MeO in storage tank x It reacts with external carbon-containing fuels to produce gaseous products CO2 and H2O and solid products CaO / MeO. x-1 The reaction temperature is 850-950℃, the reaction pressure is atmospheric pressure, and the heat required for the reaction process is provided by electric heating.

7. The system according to claim 6, characterized in that, The solid product CaO / MeO x-1 Transported back to CaO / MeO x-1 The waste is then returned to the carbonation / oxidation reactor for recycling. The gaseous products CO2 and H2O enter the Rankine cycle section, and the heat they carry is recovered and used to generate electricity. The condensed CO2 is separated from H2O to obtain high-purity CO2.

8. The system according to claim 7, characterized in that, The Rankine cycle includes a waste heat boiler, a steam turbine unit, a steam turbine generator, a product condenser, a water pump, and a condenser. The waste heat boiler is connected to the product condenser and the steam turbine unit respectively. The steam turbine unit is connected to the condenser. The condenser is connected to the waste heat boiler through a water pump. The gaseous products CO2 and H2O are cooled in the waste heat boiler and transported to the product condenser, where they are separated as gaseous CO2 and liquid H2O. The heat obtained in the waste heat boiler generates high-pressure steam, which is then fed into the turbine unit to expand and do work, driving the turbine generator to generate electricity. The exhaust steam from the turbine unit enters the condenser and condenses to form condensate. After being cooled, the condensate is pressurized by a water pump and transported back to the waste heat boiler to absorb heat and obtain high-pressure steam, forming a Rankine cycle.

9. The system according to claim 7, characterized in that, The carbon-containing fuel includes one or more of natural gas, biomass, ammonia, or hydrogen; MeO x The mass ratio of carbon-containing fuel to electric heating is 10-30:1; the electric heating can be carried out using off-peak electricity and / or renewable green electricity, thereby converting renewable energy electricity into the chemical energy of solid materials.

10. The system according to claim 1, characterized in that, The CO2 release / absorption unit is used to capture CO2 in the flue gas of coal-fired power plants, natural gas power plants or biomass power plants and release energy from solid energy storage materials; the CO2 storage / release unit converts the energy of solid energy storage materials into electricity and obtains high-purity CO2, thereby realizing the storage of off-peak electricity and / or green electricity and CO2 capture.

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