Solar driven air thermochemical deoxygenation direct air carbon capture method and system

Abstract

The present application relates to the technical field of direct air carbon capture, in particular to a solar-driven air thermo-chemical deoxidization direct air carbon capture method and system, the present application adopts chemical looping air separation technology, first removes oxygen in air through an oxidation reactor and a reduction reactor, then sends the oxygen-poor air into a DAC carbon capture unit for decarburization, which can greatly reduce the air treatment amount of the DAC unit; at the same time, the present application uses solar energy to power the chemical looping reduction reactor, realizing clean and efficient power supply of the DAC unit; therefore, the solar-driven air thermo-chemical deoxidization direct air carbon capture method and system of the present application adopts a combination of chemical looping air separation and DAC, and uses the oxygen-poor air at the outlet of the chemical looping air separation oxidation reactor to drive a waste heat power generation unit to generate power, so as to meet the power and steam supply of the air decarburization process, thereby solving the problems of high energy consumption and high cost of the existing DAC technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct air carbon capture, in particular to a solar-driven air thermo-chemical deoxidization direct air carbon capture method and system. BACKGROUND

[0002] As an important technical means to cope with global climate change, direct air capture (DAC) technology is increasingly becoming a core component of emission reduction strategies in various countries. This technology has the characteristics of efficient capture of carbon dioxide from the atmosphere and flexible deployment, and can operate in diverse environments and effectively combine with renewable energy systems to achieve negative carbon emissions.

[0003] Due to its effect, direct air capture technology has attracted much attention and research. For example, patent technology document CN115445384A discloses a wind-solar complementary driven direct air carbon capture system and method for greenhouse, which uses wind energy and solar energy to complement power generation, can capture carbon dioxide from the air without additional carbon dioxide production, reduces the concentration of carbon dioxide in the air, and realizes the on-site utilization of carbon dioxide and the supply of carbon dioxide gas fertilizer for the greenhouse, thereby reducing the energy consumption and cost of direct air carbon capture technology. The invention can also realize continuous capture of carbon dioxide in the air and continuous supply of carbon dioxide products through intermittent operation of the carbon dioxide adsorption-thermal regeneration reactor, with high carbon dioxide capture efficiency, low adsorbent regeneration energy consumption, and flexible adjustment of system size according to demand. The invention closely combines air carbon capture with greenhouse gas fertilizer supply, not only realizes air carbon reduction, but also realizes on-site utilization of carbon dioxide products, provides a new type of pollution-free greenhouse carbon dioxide gas fertilizer technology, improves greenhouse crop yield, and increases crop carbon sink for the wind-solar complementary driven direct air carbon capture system and method for greenhouse.

[0004] However, the high energy consumption and high cost of these existing DAC technologies seriously hinder their development and deployment. For low-temperature adsorption DAC technology, energy consumption mainly occurs in the air compression process. However, due to the extremely low concentration of carbon dioxide in the air, compared with typical coal-fired flue gas, the air handling capacity of DAC technology is larger at the same carbon capture amount, and the corresponding air compression process consumes a lot of energy.

[0005] Therefore, according to the related technology in the above, it is urgent to develop a solar-driven air thermo-chemical deoxidization direct air carbon capture method and system. SUMMARY

[0006] Therefore, according to the related technology in the above, it is urgent to develop a solar-driven air thermo-chemical deoxidization direct air carbon capture method and system.

[0007] Based on the above purpose, the present application provides a solar-driven air thermo-chemical deoxidization direct air carbon capture method and system.

[0008] A solar-driven air thermo-chemical deoxidization direct air carbon capture method, comprising the following steps:

[0009] Step S1: After the air enters the oxidation reactor, it reacts with the metal oxygen carrier Me to generate MeO, and the oxygen in the air is consumed to become oxygen-poor air;

[0010] The MeO generated in the oxidation reactor enters the reduction reactor and is reduced to Me and pure oxygen under the thermal drive of solar energy;

[0011] The pure oxygen produced by the reduction reactor can be used for sale or oxygen supply for other energy processes;

[0012] The Me reduced in the reduction reactor will return to the oxidation reactor to continue to react with the oxygen in the air;

[0013] The pure oxygen is discharged from the outlet of the reduction reactor;

[0014] Step S2: The oxygen-poor air generated in the oxidation reactor enters the adsorption tower and contacts with the adsorbent to remove carbon dioxide in the oxygen-poor air, producing decarburized air and adsorbent completed with carbon dioxide adsorption;

[0015] The decarburized air is discharged from the adsorption tower to the atmospheric environment;

[0016] Step S3: The adsorbent completed with carbon dioxide adsorption produced by the adsorption tower enters the desorption tower to complete the desorption of carbon dioxide and returns to the adsorption tower again to continue to react with carbon dioxide in the air.

[0017] Preferably, MeO and Me storage tanks are arranged between the oxidation reactor and the reduction reactor to adjust the instability of solar energy supply, and the excess solar energy is stored in the metal oxygen carrier Me during the day, and the air is reacted with Me to supply energy for the air decarburization process at night;

[0018] A waste heat power generation unit and a compressor are sequentially arranged between the oxidation reactor and the adsorption tower.

[0019] Preferably, the oxygen-poor air passes through compression during the process of entering the adsorption tower from the outlet of the oxidation reactor.

[0020] Preferably, the oxygen-poor air at the outlet of the oxidation reactor is used to drive the waste heat boiler to generate power, thereby providing electric energy and steam for the oxygen-poor air decarburization process;

[0021] The compression work required by the oxygen-poor air compression process is provided by the waste heat power generation unit, and the pumping work required by the vacuumization process of the desorption tower is provided by the waste heat power generation unit.

[0022] The heat energy required by the desorption tower desorption process is provided by extraction steam of a waste heat power generation unit.

[0023] Preferably, the adsorbent is an adsorbent prepared by loading organic amines on a solid porous material carrier;

[0024] The solid porous material is any one of zeolite, activated carbon, MOF material;

[0025] The organic amine is obtained by mixing primary amines and tertiary amines;

[0026] The tertiary amine is any one of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene;

[0027] The primary amine is any one of ethanolamine, 2-amino-2-methyl-1-propanol;

[0028] The adsorbent is prepared by a physical impregnation method.

[0029] Preferably, the metal oxygen carrier Me is any one of cobalt, copper, manganese.

[0030] Preferably, the reaction pressure in the oxidation reactor is 1-10 bar, and the reaction temperature is 900-1000℃;

[0031] The reaction temperature in the reduction reactor is 500-600℃.

[0032] Preferably, the working pressure of the adsorption tower is 1.5-3 bar to achieve a higher carbon dioxide adsorption amount;

[0033] The working pressure of the desorption tower is 0.01-0.1 bar to achieve a carbon dioxide recovery rate of about 90% and a carbon dioxide purity of more than 95%.

[0034] The application discloses a solar-driven air thermo-chemical deoxidization direct air carbon capture system, which comprises a solar heat collection field, a reduction reactor, an oxidation reactor, an adsorption tower and a desorption tower connected in sequence.

[0035] Preferably, the solar-driven air thermo-chemical deoxidization direct air carbon capture system further comprises a MeO storage tank, a Me storage tank and a waste heat recovery power generation unit, wherein the MeO storage tank and the Me storage tank are connected with the oxidation reactor and the reduction reactor, the MeO storage tank is used for storing the metal oxide MeO at the outlet of the oxidation reactor, and the Me storage tank is used for storing the metal Me at the outlet of the reduction reactor, so as to suppress the fluctuation of solar energy and realize long-time stable carbon capture.

[0036] The application has the following beneficial effects:

[0037] The application provides a solar-driven air thermo-chemical deoxidization direct air carbon capture method and system, and the chemical chain air separation technology is adopted to remove oxygen in air through the oxidation reactor and the reduction reactor, and then the oxygen-poor air is sent into a DAC carbon capture unit to perform deoxidization, so that the air treatment amount of the DAC unit can be greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the present application or the prior art, the drawings needed to be used in the following embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only a part of the present application, and other drawings can also be obtained by those skilled in the art without creative effort.

[0039] Figure 1 A solar energy driven air thermo-chemical deoxygenation direct air carbon capture method diagram in the present application;

[0040] Figure 2 A traditional low-temperature adsorption direct air carbon capture system diagram;

[0041] Figure 3 A solar energy driven air thermo-chemical deoxygenation direct air carbon capture system diagram in the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the present application will be further described in detail below in combination with specific embodiments.

[0043] Embodiment 1: A solar energy driven air thermo-chemical deoxygenation direct air carbon capture method is as follows:

[0044] S1: According to the attached drawings Figure 3 The solar heat collection field, the reduction reactor, the MeO storage tank, the Me storage tank, the oxidation reactor, the waste heat power generation unit, the adsorption tower and the desorption tower are assembled into a solar energy driven air thermo-chemical deoxygenation direct air carbon capture system. Compared with the traditional low-temperature adsorption DAC system, the system adopts the chemical looping air separation technology, first passes the air into the chemical looping oxidation reactor to react with the metal Me, removes the oxygen in the air, then after compression, sends it into the adsorption tower for decarburization. At the same time, during the day, the concentrated solar energy is used to provide energy for the chemical looping deoxygenation process, a part of the solar energy is stored as chemical energy of the metal oxygen carrier, another part absorbs the oxygen in the air, and through the recovery of high-temperature waste heat, electricity and heat are generated to provide heat consumption and compression work for DAC. At night, the metal oxygen carrier in the storage tank is reacted with air to provide energy for DAC, and stable energy supply is realized;

[0045] S2: 30g of 1,8-diazabicyclo[5.4.0]undec-7-ene is mixed with 10g of ethanolamine, and then the zeolite is immersed therein to obtain an adsorbent;

[0046] S3: The adsorbent is placed in the adsorption tower;

[0047] S4: The cobalt is placed in the oxidation reactor and the reaction pressure in the oxidation reactor is set to 1 bar and the reaction temperature is 900℃;

[0048] S5: Set the reaction temperature in the reduction reactor to 500℃;

[0049] S6: Set the working pressure of the adsorption tower to 1.5 bar;

[0050] S7: Set the working pressure of the desorption tower to 0.1 bar;

[0051] S8: Introduce air into the oxidation reactor;

[0052] S9: Collect the decarburized air discharged from the adsorption tower and the carbon dioxide discharged from the desorption tower;

[0053] Example 2: A solar-driven air thermochemical deoxygenation direct air carbon capture method is as follows:

[0054] S1: According to the attached Figure 3 The solar heat collection field, the reduction reactor, the MeO storage tank, the Me storage tank, the oxidation reactor, the waste heat power generation unit, the adsorption tower, and the desorption tower are assembled into a solar-driven air thermochemical deoxygenation direct air carbon capture system;

[0055] S2: 30 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene is mixed with 13 g of ethanolamine, and then activated carbon is immersed therein to obtain an adsorbent;

[0056] S3: The adsorbent is placed into the adsorption tower;

[0057] S4: Copper is placed into the oxidation reactor, and the reaction pressure in the oxidation reactor is set to 5 bar, and the reaction temperature is 950℃;

[0058] S5: The reaction temperature in the reduction reactor is set to 550℃;

[0059] S6: The working pressure of the adsorption tower is set to 2.5 bar;

[0060] S7: The working pressure of the desorption tower is set to 0.05 bar;

[0061] S8: Air is introduced into the oxidation reactor;

[0062] S9: The decarburized air discharged from the adsorption tower and the carbon dioxide discharged from the desorption tower are collected;

[0063] Example 3: A solar-driven air thermochemical deoxygenation direct air carbon capture method is as follows:

[0064] S1: According to the attached Figure 3 The solar heat collection field, the reduction reactor, the MeO storage tank, the Me storage tank, the oxidation reactor, the waste heat power generation unit, the adsorption tower, and the desorption tower are assembled into a solar-driven air thermochemical deoxygenation direct air carbon capture system;

[0065] S2: 30 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene is mixed with 15 g of 2-amino-2-methyl-1-propanol, and then the MOF material is immersed therein to obtain an adsorbent;

[0066] S3: The adsorbent is placed into an adsorption tower;

[0067] S4: Manganese is placed into an oxidation reactor, and the reaction pressure in the oxidation reactor is set to 10 bar, and the reaction temperature is 1000°C;

[0068] S5: The reaction temperature in the reduction reactor is set to 600°C;

[0069] S6: The working pressure of the adsorption tower is set to 3 bar;

[0070] S7: The working pressure of the desorption tower is set to 0.01 bar;

[0071] S8: Air is introduced into the oxidation reactor;

[0072] S9: Decarburized air discharged from the adsorption tower and carbon dioxide discharged from the desorption tower are collected;

[0073] Comparative Example 1:

[0074] This comparative example is compared with Example 1 only by replacing "1,8-diazabicyclo[5.4.0]undec-7-ene and ethanolamine" used in the adsorbent preparation process with "1,8-diazabicyclo[5.4.0]undec-7-ene", and the rest of the steps and parameters are the same, and this comparative example will not be repeated here. Ultimately, carbon dioxide and decarburized air are obtained;

[0075] Comparative Example 2:

[0076] This comparative example is compared with Example 1 only by replacing "1,8-diazabicyclo[5.4.0]undec-7-ene and ethanolamine" used in the adsorbent preparation process with "ethanolamine", and the rest of the steps and parameters are the same, and this comparative example will not be repeated here. Ultimately, carbon dioxide and decarburized air are obtained;

[0077] Comparative Example 3:

[0078] This comparative example is compared with Example 1 only by replacing "1,8-diazabicyclo[5.4.0]undec-7-ene and ethanolamine" used in the adsorbent preparation process with "polyethyleneimine", and the rest of the steps and parameters are the same, and this comparative example will not be repeated here. Ultimately, carbon dioxide and decarburized air are obtained;

[0079] Comparative Example 4:

[0080] The comparative example is compared with example 1 without MeO and Me storage tanks between the oxidation reactor and the reduction reactor, and the remaining steps and parameters are the same. The comparative example will not be repeated. Finally, carbon dioxide and decarburized air are obtained;

[0081] Comparative example 5:

[0082] The comparative example is compared with example 1, only replacing the working pressure of the adsorption tower from “1.5 bar” to “0.5 bar”, and the remaining steps and parameters are the same. The comparative example will not be repeated. Finally, carbon dioxide and decarburized air are obtained;

[0083] Comparative example 6:

[0084] The comparative example is compared with example 1, only replacing the working pressure of the desorption tower from “0.1 bar” to “1 bar”, and the remaining steps and parameters are the same. The comparative example will not be repeated. Finally, carbon dioxide and decarburized air are obtained.

[0085] Performance test:

[0086] According to the test standard of “GB / T18204.24 Public place health test method, second part: Chemical pollutants”, the purity and carbon dioxide recovery rate of carbon dioxide distributed at 00:00 and 12:00 of each day in example 1- example 3 and comparative example 1- comparative example 6 are determined; the average value of 30 days is taken as the determination result, and finally it is found that the solar-driven air thermochemical decarburization direct air carbon capture method and system has more excellent carbon dioxide recovery capacity and recovery stability; this may be due to the adsorbent provided by the application is prepared by compounding tertiary amine and primary amine, and the compounding of tertiary amine and primary amine has stronger carbon dioxide affinity capacity; and when the MeO storage tank and the Me storage tank are connected with the oxidation reactor and the reduction reactor, the MeO storage tank can be used to store the metal oxide MeO at the outlet of the oxidation reactor, and the Me storage tank can be used to store the metal Me at the outlet of the reduction reactor, so as to suppress the volatility of solar energy and realize long-term stable carbon capture; the working pressure of the adsorption tower and the desorption tower is also the best working pressure adjusted by the application, which can make the application have more excellent carbon dioxide recovery capacity;

[0087] Figure 2 The traditional low-temperature adsorption DAC process flowchart is composed of an adsorption tower and a desorption tower. Air is first compressed by a compressor and then enters the adsorption tower to contact the adsorbent. CO2 in the air is removed, and decarburized air is discharged from the top of the adsorption tower. Then, the adsorbent that has adsorbed CO2 enters the desorption tower for regeneration. The desorption tower is maintained in a vacuum environment by a vacuum pump to ensure a high CO2 desorption rate. The power and steam required for regeneration are provided externally.

[0088] Figure 3 The system of the solar-driven air thermo-chemical deoxidization direct air carbon capture method provided by the application is composed of a solar heat collection field, a reduction reactor, a MeO storage tank, a Me storage tank, an oxidation reactor, a waste heat power generation unit, an adsorption tower and a desorption tower. Compared with a traditional low-temperature adsorption DAC system, the system adopts a chemical looping air separation technology, air is first introduced into a chemical looping oxidation reactor to react with metal Me, oxygen in the air is removed, and then the compressed air is sent into the adsorption tower for decarburization. At the same time, during the day, concentrated solar energy is used to provide energy for the chemical looping deoxidization process, a part of the solar energy is stored as chemical energy of the metal oxygen carrier, another part of the solar energy absorbs oxygen in the air, and electricity and heat are generated by recycling high-temperature waste heat, thereby providing heat consumption and compression work for DAC. At night, the metal oxygen carrier in the storage tank is reacted with air to provide energy for DAC, thereby realizing stable energy supply.

[0089] In combination with Figure 1 and Figure 2 It can be known that, compared with the prior art, the application solves the problems of high energy consumption and high cost of the existing DAC technology, and has more excellent carbon dioxide recovery capacity and recovery stability;

[0090] This may be because, by adopting the chemical looping air separation technology, the oxygen in the air is first removed, and then the oxygen-poor air is sent into the DAC carbon capture unit for decarburization, which can greatly reduce the air treatment amount of the DAC unit, and is expected to reduce the air compression work by about 20%-30%, and at the same time, the carbon dioxide concentration in the captured air is increased, and the capture energy consumption is reduced. The application uses solar energy to supply energy for the chemical looping reduction reactor, realizes clean and efficient energy supply for the DAC unit, and at the same time, the storage tank is additionally provided to store energy, thereby realizing long-period stable operation of the DAC capture technology. The application adopts the chemical looping air separation and DAC combined mode, and the oxygen-poor air at the outlet of the chemical looping air separation oxidation reactor is used to drive the waste heat power generation unit to generate electricity, thereby meeting the supply of electricity and steam for the air decarburization process, realizing self-sufficiency of the system energy demand, and at the same time, the electricity and steam can be outputted to the outside.

[0091] Those skilled in the art should understand that the discussion of any of the above embodiments is only exemplary, and is not intended to imply that the scope of the application is limited to these examples; under the idea of the application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the application as described above. In order to be brief, they are not provided in details.

[0092] The present application is intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the appended claims. Accordingly, any and all such alternatives, modifications, equivalents, improvements and the like are intended to be encompassed by the present application.

Claims

1. A solar-driven air thermochemical deoxygenation direct air carbon capture method, characterized in that, It comprises the following steps: Step S1: After the air enters the oxidation reactor, it reacts with the metal oxygen carrier Me to generate MeO, and the oxygen in the air is consumed to become oxygen-poor air. The MeO generated in the oxidation reactor enters the reduction reactor and is reduced to Me and pure oxygen under the heat drive of solar energy. The Me reduced in the reduction reactor returns to the oxidation reactor to continue to react with the oxygen in the air; Step S2: The oxygen-poor air generated in the oxidation reactor enters the adsorption tower and is in contact with the adsorbent to remove carbon dioxide in the oxygen-poor air, thereby generating decarburized air and the adsorbent that has completed carbon dioxide adsorption. The adsorbent is prepared by loading organic amine on a solid porous material carrier; The solid porous material is any one of zeolite, activated carbon, and MOF material; The organic amine is obtained by mixing primary amine and tertiary amine; The tertiary amine is any one of 1,8-diazabicyclo[5.4.0]undec-7-ene and 1,5,7-triazabicyclo[4.4.0]dec-5-ene; The primary amine is any one of ethanolamine and 2-amino-2-methyl-1-propanol; The mass ratio of the primary amine to the tertiary amine is 3:1-1.5; Step S3: The adsorbent that has completed carbon dioxide adsorption generated by the adsorption tower enters the desorption tower to complete the desorption of carbon dioxide, and then returns to the adsorption tower to continue to react with carbon dioxide in the air.

2. The solar-driven air thermochemical deoxygenation direct air carbon capture method according to claim 1, wherein, The pure oxygen is discharged from the outlet of the reduction reactor; The oxygen-poor air is compressed during the process of entering the adsorption tower from the outlet of the oxidation reactor; The decarburized air is discharged from the adsorption tower to the atmospheric environment.

3. The solar-driven air thermochemical deoxygenation direct air carbon capture method according to claim 1, wherein, The metal oxygen carrier Me is any one of cobalt, copper, and manganese.

4. The solar-driven air thermochemical deoxygenation direct air carbon capture method according to claim 1, wherein, The reaction pressure in the oxidation reactor is 1-10 bar; The reaction temperature in the oxidation reactor is 900-1000℃; The reaction temperature in the reduction reactor is 500-600℃.

5. The solar-driven air thermochemical deoxygenation direct air carbon capture method according to claim 1, wherein, The working pressure of the adsorption tower is 1.5-3 bar, and the working pressure of the desorption tower is 0.01-0.1 bar.

6. A solar-driven air thermochemical deoxygenation direct air carbon capture system according to any one of claims 1-5, characterized in that, The solar-driven air thermochemical deoxygenation direct air carbon capture system comprises, in sequence, a solar heat collection field, a reduction reactor, an oxidation reactor, an adsorption tower, and a desorption tower; MeO storage tanks and Me storage tanks are arranged between the oxidation reactor and the reduction reactor; A waste heat power generation unit and a compressor are sequentially arranged between the oxidation reactor and the adsorption tower.

7. The solar-driven air thermochemical deoxygenation direct air carbon capture system of claim 6, wherein, The compression work required by the compression process of the oxygen-poor air is provided by the waste heat power generation unit; The pump work required by the vacuumization process of the desorption tower is provided by the waste heat power generation unit; The heat energy required by the desorption process of the desorption tower is provided by the steam extraction of the waste heat power generation unit.

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