System and method for CO2 capture and electroregeneration and synchronous conversion

Abstract

A system and method for CO.sub.2 capture and electroregeneration and synchronous conversion are provided. The system includes a CO.sub.2 capture subsystem, which uses an absorption liquid to capture CO.sub.2 and generate a capture liquid; and a CO.sub.2 electroregeneration and synchronous conversion subsystem, including a cathode chamber provided with a cathode electrode, a sample inlet, and a sample outlet, an anode chamber having an anode electrode, a sample inlet connected to an outlet of the capture liquid of the CO.sub.2 capture subsystem, and a sample outlet connected to the sample inlet of the cathode chamber for introducing CO.sub.2 regenerated by anodic oxidation into the cathode chamber for electroreduction, and a balance chamber in the middle having a sample outlet connected to an inlet of the absorption liquid of the CO.sub.2 capture subsystem. The system can perform self-circulation and stably operate, to capture, regenerate and convert CO.sub.2.

Claims

1. A system for CO.sub.2 capture and electroregeneration and synchronous conversion, comprising: a CO.sub.2 capture subsystem and a CO.sub.2 electroregeneration and synchronous conversion subsystem; wherein the CO.sub.2 capture subsystem uses an absorption liquid to capture CO.sub.2 and generate a capture liquid; the CO.sub.2 electroregeneration and synchronous conversion subsystem comprises an electrolytic cell; a cation exchange membrane and an anion exchange membrane are arranged in the electrolytic cell at an interval, the cation exchange membrane and the anion exchange membrane separate the electrolytic cell into an anode chamber and a cathode chamber at the left and right ends, and a balance chamber in the middle; an anode electrode is arranged in the anode chamber, the anode chamber is further provided with a sample inlet and a sample outlet; a cathode electrode is arranged in the cathode chamber, and the cathode chamber is further provided with a sample inlet and a sample outlet; the balance chamber is provided with a sample outlet; and the sample inlet of the anode chamber is connected to an outlet of the capture liquid of the CO.sub.2 capture subsystem, and the sample outlet of the anode chamber is connected to the sample inlet of the cathode chamber for introducing CO.sub.2 regenerated by anodic oxidation into the cathode chamber for electroreduction; and the sample outlet of the balance chamber is connected to an inlet of the absorption liquid of the CO.sub.2 capture subsystem.

2. The system for CO.sub.2 capture and electroregeneration and synchronous conversion according to claim 1, wherein the anode electrode is an inert electrode, and the cathode electrode is provided with a catalyst catalyzing CO.sub.2 to have an electroreduction reaction.

3. The system for CO.sub.2 capture and electroregeneration and synchronous conversion according to claim 1, wherein the CO.sub.2 electroregeneration and synchronous conversion subsystem further comprises a power supply, and the anode electrode and the cathode electrode are connected to two ends of the power supply respectively.

4. The system for CO.sub.2 capture and electroregeneration and synchronous conversion according to claim 1, wherein the CO.sub.2 capture subsystem comprises a spray tower, a liquid storage tank and a spray device; the spray tower is provided with a gas inlet, a gas outlet, tower plates and a demister; the liquid storage tank comprises a liquid storage tank body A and a liquid storage tank body B; the liquid storage tank body A receives the capture liquid at a bottom of the spray tower and is connected to the sample inlet of the anode chamber; the liquid storage tank body B stores fresh alkali absorption liquid and is connected to the sample outlet of the balance chamber; and the spray device comprises a pump, a spray head and pipelines; and the spray head is connected to the liquid storage tank body B through the pipelines, and the pump is arranged on the pipelines.

5. A method for CO.sub.2 capture and electroregeneration and synchronous conversion of the system for CO.sub.2 capture and electroregeneration and synchronous conversion according to claim 1, comprising: introducing a gas containing CO.sub.2 into the CO.sub.2 capture subsystem and capturing CO.sub.2 by means of the absorption liquid to generate the capture liquid; introducing the capture liquid into the anode chamber of the CO.sub.2 electroregeneration and synchronous conversion subsystem, using the capture liquid as an anode electrolyte of the anode chamber, and enabling carbonate ions CO.sub.3.sup.2? in the capture liquid to be regenerated into CO.sub.2 by electrooxidation while generating cations, the cations entering the balance chamber through the cation exchange membrane; introducing the regenerated CO.sub.2 into the cathode chamber for electroreduction to generate high value-added products while consuming protons H.sup.+ to increase a concentration of hydroxide ions OH.sup.?, the hydroxide ions OH.sup.? entering the balance chamber through the anion exchange membrane; regenerating the hydroxide ions OH.sup.? and the cations in the balance chamber into a new absorption liquid; and introducing the regenerated new absorption liquid into the CO.sub.2 capture subsystem for capturing CO.sub.2, forming a cycle of CO.sub.2 capture, electroregeneration and synchronous conversion.

6. The method for CO.sub.2 capture and electroregeneration and synchronous conversion according to claim 5, further comprising: discharging the high value-added products through the sample outlet of the cathode chamber.

7. The method for CO.sub.2 capture and electroregeneration and synchronous conversion according to claim 5, further comprising: providing the cathode electrode with a catalyst for CO.sub.2 electroreduction, achieving oriented preparation of different high value-added products from CO.sub.2 by changing the catalyst, wherein the value-added product is CO, methane, methanol, formic acid, ethanol, acetic acid or propanol.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The FIGURE is a structural schematic diagram of a system according to an embodiment of the present disclosure.

(2) In the FIGURE: 1, CO.sub.2 capture subsystem; 11, spray tower; 111, tower plate; 112, demister; 12, liquid storage tank; 121, liquid storage tank body A; 122, liquid storage tank body B; 13, spray device; 131, pump; 132, spray head; 133, pipeline; 2, CO.sub.2 electroregeneration and synchronous conversion subsystem; 21, power supply; 22, electrolytic cell; 23, cation exchange membrane; 24, anion exchange membrane; 25, anode chamber; 251, anode electrode; 26, cathode chamber; 261, cathode electrode; and 27, balance chamber.

DETAILED DESCRIPTION

(3) Implementations of the present disclosure will be described below in combination with the accompanying drawing.

(4) As shown in the FIGURE, a system for CO.sub.2 capture and electroregeneration and synchronous conversion of the present application includes a CO.sub.2 capture subsystem 1 and a CO.sub.2 electroregeneration and synchronous conversion subsystem 2.

(5) The CO.sub.2 capture subsystem 1 uses an absorption liquid to capture CO.sub.2 and generate a capture liquid.

(6) The CO.sub.2 electroregeneration and synchronous conversion subsystem 2 includes an electrolytic cell 22; a cation exchange membrane 23 and an anion exchange membrane 24 are arranged in the electrolytic cell 22 at an interval, and the cation exchange membrane 23 and the anion exchange membrane 24 separate the electrolytic cell 22 into an anode chamber 25 and a cathode chamber 26 at the left and right ends, and a balance chamber 27 in the middle.

(7) An anode electrode 251 and an anode electrolyte are arranged in the anode chamber 25, and the anode chamber 25 is further provided with a sample inlet and a sample outlet.

(8) A cathode electrode 261 and a cathode electrolyte are arranged in the cathode chamber 26, the cathode electrolyte is an electrolyte required for an electroreduction reaction of CO.sub.2; the cathode chamber 26 is further provided with a sample inlet and a sample outlet; and the balance chamber 27 is provided with a sample outlet.

(9) The sample inlet of the anode chamber 25 is connected to an outlet of the capture liquid of the CO.sub.2 capture subsystem 1, for using the capture liquid as the anode electrolyte.

(10) The sample outlet of the anode chamber 25 is connected to the sample inlet of the cathode chamber 26, for introducing CO.sub.2 regenerated by anodic oxidation into the cathode chamber 26 for reduction.

(11) The sample outlet of the balance chamber 27 is connected to an inlet of the absorption liquid of the CO.sub.2 capture subsystem 1, for supplementing an absorption liquid to the CO.sub.2 capture subsystem 1.

(12) Specifically, the anode electrode 251 is an inert electrode, and the cathode electrode 261 is provided with a catalyst catalyzing CO.sub.2 to have an electroreduction reaction.

(13) Specifically, the cathode electrolyte is one of a KHCO.sub.3 solution or a KCl solution with a concentration of 0.1 to 1 mol/L.

(14) Specifically, the anion exchange membrane 24 is a hydroxide ion exchange membrane.

(15) Specifically, the sample outlet of the anode chamber 25 and the sample inlet of the cathode chamber 26 are connected by an external channel, allowing the electroregenerated CO.sub.2 to enter the cathode chamber 26 for reduction.

(16) Specifically, the CO.sub.2 electroregeneration and synchronous conversion subsystem 2 further includes a power supply 21, and the anode electrode 251 and the cathode electrode 261 are connected to the two ends of the power supply 21 respectively.

(17) Specifically, the structure of the CO.sub.2 capture subsystem 1 includes a spray tower 11, a liquid storage tank 12 and a spray device 13.

(18) Specifically, the spray tower 11 is provided with a gas inlet, a gas outlet, tower plates 111 and a demister 112; the tower plates 111 are staggered to increase the contact area of a spray liquid and CO.sub.2.

(19) Specifically, the liquid storage tank 12 includes a liquid storage tank body A 121 and a liquid storage tank body B 122; the liquid storage tank body A 121 receives the capture liquid at the bottom of the spray tower 11 and is connected to the sample inlet of the anode chamber 25; the fresh alkali absorption liquid is in the liquid storage tank body B 122 and is connected to the sample outlet of the balance chamber 27.

(20) The spray device 13 includes a pump 131, a spray head 132 and pipelines 133; the spray head 132 is connected to the liquid storage tank body B 122 through the pipelines 133, and the pump 131 is arranged on the pipelines 133.

(21) According to the system for CO.sub.2 capture and electroregeneration and synchronous conversion, the CO.sub.2 capture liquid generated by the CO.sub.2 capture subsystem 1 flows into the CO.sub.2 electroregeneration and synchronous conversion subsystem 2, and the absorption liquid regenerated by the CO.sub.2 electroregeneration and synchronous conversion subsystem 2 flows back to the CO.sub.2 capture subsystem 1, so that the CO.sub.2 capture subsystem 1 and the CO.sub.2 electroregeneration and synchronous conversion subsystem 2 are organically connected in series, achieving CO.sub.2 capture, regeneration and synchronous conversion, which enables the overall system to operate stably.

(22) A method for CO.sub.2 capture and electroregeneration and synchronous conversion of the system for CO.sub.2 capture and electroregeneration and synchronous conversion of the present application includes: introducing the gas containing CO.sub.2 into the CO.sub.2 capture subsystem 1 and capturing CO.sub.2 by means of an absorption liquid to generate a capture liquid; introducing the capture liquid into the anode chamber 25 of the CO.sub.2 electroregeneration and synchronous conversion subsystem 2, using the capture liquid as an anode electrolyte of the anode chamber 25, and enabling carbonate ions CO.sub.3.sup.2? in the capture liquid to be regenerated into CO.sub.2 by electrooxidation while generating cations, the cations entering the balance chamber 27 through the cation exchange membrane 23; introducing the regenerated CO.sub.2 into the cathode chamber 26 for electroreduction to generate high value-added products while consuming protons H.sup.+ in the solution to increase the concentration of hydroxide ions OH.sup.?, the hydroxide ions OH.sup.? entering the balance chamber 27 through the anion exchange membrane 24; regenerating the hydroxide ions OH.sup.? and the cations in the balance chamber 27 into a new absorption liquid; and introducing the regenerated new absorption liquid into the CO.sub.2 capture subsystem 1 for capturing CO.sub.2, forming a cycle of CO.sub.2 capture, electroregeneration and synchronous conversion.

(23) The method for CO.sub.2 capture and electroregeneration and synchronous conversion further includes: discharging the high value-added products through the sample outlet of the cathode chamber 26.

(24) The method for CO.sub.2 capture and electroregeneration and synchronous conversion further includes: the cathode electrode 261 being provided with a catalyst for CO.sub.2 electroreduction, achieving the oriented preparation of different high value-added products, such as CO, methane, methanol, formic acid, ethanol, acetic acid or propanol, from CO.sub.2 by changing the type of the catalyst.

(25) As an implementation, the above method for CO.sub.2 capture and electroregeneration and synchronous conversion, as shown in the FIGURE, includes as follows: the gas containing CO.sub.2 is introduced from the gas inlet at the bottom of the spray tower 11 of the CO.sub.2 capture subsystem 1, and the spray device 13 pumps the fresh CO.sub.2 absorption liquid in the liquid storage tank body B 122 to the top of the spray tower 11 for spraying, with the gas flowing from bottom to top and the absorption liquid flowing from top to bottom; the capture liquid after capturing CO.sub.2 flows into the liquid storage tank body A 121, and the gas is discharged from the gas outlet after being de-watered by the demister 112; the CO.sub.2 capture liquid stored in the liquid storage tank body A 121 is introduced to the sample inlet of the anode chamber 25 of the CO.sub.2 electroregeneration and synchronous conversion subsystem 2, and the carbonate ions CO.sub.3.sup.2? in the CO.sub.2 capture liquid is electrooxidized to generate CO.sub.2, which then flows out from the sample outlet of the anode chamber 25 and flows to the sample inlet of the cathode chamber 26 through an external channel; cations in the anode chamber 25 enter the balance chamber 27 through the cation exchange membrane 23 under the effect of the concentration difference; CO.sub.2 entering from the sample inlet of the cathode chamber 26 through the external channel undergoes an electroreduction reaction under the action of the catalyst in the cathode electrode 261 to produce high-value products; hydrogen ions H.sup.+ in the solution are consumed simultaneously in the electroreduction process of CO.sub.2, and the concentration of hydroxide ions OH.sup.? in the cathode chamber 26 gradually increases, which enter the balance chamber 27 through the anion exchange membrane 24 under the action of the concentration difference; the cations (M.sup.+ ions as shown in the FIGURE) entering the balance chamber 27 from the anode chamber 25 through the cation exchange membrane 23 and the hydroxide ions OH.sup.? entering the balance chamber 27 from the cathode chamber 26 through the anion exchange membrane 24 are regenerated into a fresh CO.sub.2 absorption liquid (MOH as shown in the FIGURE) in the balance chamber 27 of the CO.sub.2 electroregeneration and synchronous conversion subsystem 2, which flows back to the liquid storage tank body B 122 of the CO.sub.2 capture subsystem 1, realizing the balanced and stable operation of the system for CO.sub.2 capture and electroregeneration and synchronous conversion.

(26) It can be understood by those skilled in the art that: the above description is only preferred embodiments of the present disclosure and is not intended to limit the present disclosure. Although the present disclosure is described in detail with reference to the foregoing embodiments, a person skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments, or make equivalent replacements to some of the technical features. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.