Search

CN-121975557-A - Green electricity direct connection CO trapping2And is coupled with supercritical CO2System and method for storing energy to produce liquid fuel

CN121975557ACN 121975557 ACN121975557 ACN 121975557ACN-121975557-A

Abstract

The invention provides a system for directly capturing CO 2 and coupling supercritical CO 2 energy storage to prepare liquid fuel by green electricity. The invention also provides a method for preparing liquid fuel by directly capturing CO 2 through green electricity and coupling supercritical CO 2 energy storage. The system and the method for preparing the liquid fuel by directly capturing CO2 through green electricity and coupling supercritical CO2 energy storage can utilize redundant electric power to compress and store multi-captured carbon dioxide to a supercritical state when the green electricity is sufficient while preparing the green hydrocarbon liquid fuel and the alcohol liquid fuel, and can perform decompression expansion work on CO 2 to generate power when the electric power is insufficient, so that fluctuation of upstream carbon dioxide materials can be dealt with, and the defect of green electricity output can be dealt with to a certain extent, and the scale and the cost of other forms of energy storage can be reduced.

Inventors

  • WANG PENG
  • ZHANG HONGXI
  • Peng yongxing
  • GUO GANG
  • CUI LINGYUN
  • DING YIHAN

Assignees

  • 上海碳生万物工程技术有限公司

Dates

Publication Date
20260505
Application Date
20251231

Claims (10)

  1. 1. A system for directly collecting CO 2 by green electricity and storing energy by coupling supercritical CO 2 to prepare liquid fuel is characterized by comprising a green electricity power supply unit (1), a CO 2 collecting unit (2) and a CO 2 buffer unit (3), the device comprises a first carbon utilization unit (4), a second carbon utilization unit (5) and a CO 2 energy storage unit (6), wherein the CO 2 capture unit (2), a CO 2 buffer unit (3), the first carbon utilization unit (4), The second carbon utilization unit (5) is communicated with the CO 2 capture unit (2) through a gas pipeline in sequence along the CO 2 input direction, the second carbon utilization unit (5) is also communicated with the CO 2 energy storage unit (6) through the gas pipeline, the CO 2 buffer unit (3) is communicated with the CO 2 energy storage unit (6) to form a circulation loop, a CO 2 compression unit (7) is arranged on the path of the CO 2 buffer unit (3) for inputting the CO 2 energy storage unit (6), a CO 2 expansion power generation unit (8) is arranged on the path of the CO 2 energy storage unit (6) for inputting the CO 2 buffer unit (3), and the green electricity supply unit (1) is respectively connected with the CO 2 capture unit (2), The first carbon utilization unit (4), the second carbon utilization unit (5), the CO 2 compression unit (7) and the CO 2 expansion power generation unit (8) are electrically connected.
  2. 2. The system for directly capturing CO 2 and coupling supercritical CO 2 energy storage to prepare liquid fuel by green electricity according to claim 1, wherein the system further comprises a steam waste heat power generation unit (9), the second carbon utilization unit (5) is respectively communicated with the CO 2 capturing unit (2) and the steam waste heat power generation unit (9) through steam pipelines, and the steam waste heat power generation unit (9) is respectively connected with the green electricity power supply unit (1) and the CO 2 expansion power generation unit (8) in an electrifying manner.
  3. 3. The system for directly capturing CO 2 and coupling supercritical CO 2 energy storage to prepare liquid fuel according to claim 1, wherein the CO 2 expansion power generation unit (8) is electrically connected with the green power supply unit (1).
  4. 4. A method for preparing liquid fuel by directly capturing CO 2 in green electricity and coupling supercritical CO 2 for energy storage, a system for preparing liquid fuel by directly capturing CO 2 in green electricity and coupling supercritical CO 2 for energy storage according to any one of claims 1 to 3, comprising the following steps: 1) Adopting green electric energy to supply power, capturing CO 2 from air and/or waste gas, and then buffering and temporarily storing; 2) And then carrying out at least one treatment selected from the following steps on the buffered CO 2 : 21 Reducing CO 2 into CO and by-producing H 2 , and carrying out thermochemical catalytic synthesis reaction on CO 2 , CO and H 2 to obtain liquid fuel and by-producing steam; 22 Compression and exotherm of CO 2 , obtaining a liquid and/or supercritical CO 2 storage, said stored CO 2 being subjected to any one of the steps selected from: 221 Continuing to store the CO 2 in a supercritical state; 222 The CO 2 in the supercritical state is heated and then decompressed, expanded, operated and generated to return to the step 1) to supply power, and partial gaseous CO 2 after expansion returns to the step 21); 3) Returning the byproduct steam obtained in step 21) to step 1) to capture CO 2 and/or generating power to step 1) for power.
  5. 5. The method of green direct capture CO 2 and coupling supercritical CO 2 energy storage for liquid fuel as claimed in claim 4 wherein step 1) comprises any one or more of the following conditions: a1 The green electric energy power supply is carried out through a green electric power supply unit; A2 The CO 2 capture is performed in a CO 2 capture unit; a3 The pressure difference of a fan is 3-7 kPa when the CO 2 is trapped; A4 The throughput of air and/or exhaust gas at the time of capturing the CO 2 is 1400-1500kNm 3 of air or 2000-5000Nm 3 of exhaust gas per 1 ton of CO 2 captured; a5 The CO 2 trap adsorbent is selected from any one or more of activated carbon, solid amine, metal Organic Frameworks (MOFs) or Covalent Organic Frameworks (COFs) in combination; a6 The captured CO 2 is buffered in a CO 2 buffer unit.
  6. 6. The method of green direct capture CO 2 and coupling supercritical CO 2 energy storage for liquid fuel as claimed in claim 4 wherein step 21) comprises any one or more of the following conditions: B1 The reduction of the CO 2 to CO and the byproduct H 2 are carried out in a first carbon utilization unit; B2 The reaction conditions of reducing the CO 2 into CO and generating the byproduct H 2 are that the voltage of an electrolytic tank is 2.5-4.5V and the pH value is 2-4; The temperature is 40-80 ℃; b3 The thermochemical catalytic synthesis reaction of CO 2 , CO, and H 2 is performed in a second carbon utilization unit; B4 The thermochemical catalytic synthesis reaction is Fischer-Tropsch synthesis and hydrogenation reaction; b5 The liquid fuel is selected from at least one of hydrocarbons or alcohols.
  7. 7. The method of green direct capture CO 2 and coupling supercritical CO 2 energy storage to produce liquid fuel of claim 6, comprising any one or more of the following conditions: c1 In the step B4, the reaction condition of the Fischer-Tropsch synthesis is that the pressure is 2-4 MPa, the temperature is 200-300 ℃, and the feeding mole ratio of H 2 /CO is 1.5-2.5; c2 In the step B4, the reaction condition of the hydrogenation reaction is that the pressure is 4-8 MPa, the temperature is 200-300 ℃, and the hydrogen consumption is 1.5-3.5wt% of Fischer-Tropsch oil; C3 In B5), the hydrocarbon is a mixture of normal and isoparaffins of C5 to C40; c4 In B5), the alcohol is selected from one or more of methanol, ethanol or glycol.
  8. 8. The method of green direct capture CO 2 and coupling supercritical CO 2 energy storage for producing a liquid fuel of claim 4, wherein step 22) or step 221) comprises any one or more of the following: d1 In step 22), the CO 2 is compressed and exothermic is performed in a CO 2 compression unit; D2 In step 22), the CO 2 is compressed and exothermic under the conditions of 10-25 MPa and 70-200 ℃ and D3) in step 22), the liquid and/or supercritical CO 2 is stored in a CO 2 energy storage unit; D4 In step 221), non-condensable impurity gases are also removed simultaneously, preferably the impurity gases are O 2 and/or N 2 .
  9. 9. The method of green direct capture CO 2 and coupling supercritical CO 2 energy storage for liquid fuel as claimed in claim 4 wherein step 22) comprises any one or more of the following conditions: E1 The supercritical CO 2 is heated and then subjected to decompression expansion to do work to generate power in a CO 2 expansion power generation unit; E2 The condition of heating the CO 2 in the supercritical state is that the temperature is between 350 and 550 ℃ and the pressure is between 10 and 25MPa; E3 The conditions of decompression expansion work doing power generation are that the pressure is reduced to 7.5-8 MPa and the temperature is reduced by 0-150 ℃.
  10. 10. The method of green direct capture CO 2 and coupling supercritical CO 2 energy storage for liquid fuel as claimed in claim 4 wherein step 3) comprises any one or more of the following conditions: F1 The byproduct steam returns to the CO 2 capturing unit to capture CO 2 ; F2 Generating electricity by the byproduct steam in a steam waste heat power generation unit; F3 The condition of generating electricity in the steam waste heat power generation unit is that the inlet pressure is 2-5 MPa and the outlet pressure is 0.2-0.5 MPa.

Description

System and method for directly capturing CO 2 through green electricity and coupling supercritical CO 2 energy storage to prepare liquid fuel Technical Field The invention belongs to the technical field of energy conservation and environmental protection, and relates to a system and a method for directly capturing CO 2 by green electricity and coupling supercritical CO 2 energy storage to prepare liquid fuel. Background Under the background of carbon peak and carbon neutralization, the utilization of wind, light and green electricity for capturing and utilizing carbon dioxide is an important means for realizing carbon emission reduction. The direct air carbon capture (DAC) is flexible in site selection, does not depend on a fossil fuel carbon emission source, can be maximally close to a green electricity generation side, can convert captured carbon dioxide into liquid fuel, can realize carbon reduction and carbon negative, and can convert unstable wind, light and green electricity into stable and high-energy-density chemical energy for storage, so that the DAC has great ecological and economic significance. However, in the utilization process of green electricity, because of the fluctuation of the output of wind, light and green electricity, great challenges are presented to the stable and efficient operation of chemical devices such as carbon capture, carbon utilization and the like. The mismatching of green electricity and carbon capture and carbon utilization can cause the electricity discarding of green electricity, the overload or insufficient load of chemical equipment, the stable operation of the chemical equipment is impacted, and the like. The adoption of battery energy storage has the problems of high cost, influence on the service life of the battery due to frequent charge and discharge and the like. The adoption of compressed air and compressed CO 2 gas for energy storage has the problems of low energy storage density, large occupied area and low energy efficiency. Pumped storage is greatly limited by natural conditions, and has strict requirements on terrains. Therefore, an energy storage scheme with lower comprehensive cost is designed, the total scale of energy storage is reduced, and the method has great significance for the development of the green direct connection-carbon capture-carbon utilization technology. On the other hand, CO 2 enters the supercritical state after exceeding 31.1 ℃ and 7.39 MPa. Supercritical CO 2(S-CO2) has the density similar to that of liquid, the viscosity is smaller than that of liquid, and the energy storage density is larger than that of gas, so that the supercritical CO 2(S-CO2) is an ideal energy storage working medium. At present, the patent and technology related to supercritical CO 2 energy storage mostly uses CO 2 as an independent closed-loop energy storage working medium, or uses the coupling of carbon emission of flue gas, energy storage of green electricity supercritical CO 2 and oil displacement, but does not have the deep coupling case of converting CO 2 into fuel by utilizing green electricity carbon capture, supercritical CO 2 energy storage and carbon, and the advantages of supercritical CO 2 energy storage cannot be furthest exerted, such as reducing the refining cost of carbon capture product gas, improving the adaptability of a carbon capture device to green electricity fluidity, reducing the capacity of a high-pressure supercritical CO 2 storage tank, the volume of a low-pressure CO 2 buffer gas tank and the like. Disclosure of Invention In view of the above-mentioned characteristics of the prior art, the present invention aims to provide a system and a method for directly capturing CO 2 by green electricity and coupling supercritical CO 2 to store energy for preparing liquid fuel, which uses wind-solar green electricity as energy source to capture carbon dioxide in gas, especially air, selectively converts the captured carbon dioxide into CO by electrochemical or electrothermal method, simultaneously prepares green hydrogen, and prepares green hydrocarbon and alcohol liquid fuel by fischer-tropsch synthesis and hydrogenation of CO 2, CO and H 2. Under the condition of sufficient green electricity, the load of the carbon capture unit is lifted to capture CO 2 more, redundant electric power is utilized to compress the carbon dioxide captured more to a supercritical state for storage, when the electric power is insufficient, the load of the carbon capture unit is reduced or stopped, and the stored supercritical CO2 is subjected to decompression expansion to do work for generating electricity, so that the fluctuation of upstream carbon dioxide materials can be dealt with, and the shortage of green electricity output can be dealt with to a certain extent. The integrated consideration of the CO 2 as an energy storage medium, capturing, utilizing and converting materials can reduce the conventional energy storage scale to the maximum extent and imp