CO2 capture and electrochemical regeneration method

Abstract

The invention discloses a CO2 capture and electrochemical regeneration method. The method comprises the following steps: absorbing CO2 in a gas source by adopting an absorbent I to obtain an absorption rich solution; the absorption rich liquid is shunted into a chamber I and a chamber III; wherein the bottom of the chamber I is communicated with the chamber II, and the chamber II and the chamber III form an electrolytic tank through an isolation material; the absorption rich solution in the chamber II is electrolyzed to obtain H < + >, O2 and an absorbent II; the absorption rich solution in the chamber III is electrolyzed to obtain OH <-> and H2; the absorption rich solution in the chamber I reacts with H < + > obtained by electrolysis in the chamber II to obtain CO2; oH <-> obtained through electrolysis in the cavity III reacts with an absorbent II which is in the cavity II and permeates into the cavity III through the isolation material, and an absorbent I is obtained. According to the CO2 capture and electrochemical regeneration method, CO2 low-temperature regeneration is synchronously achieved by means of the hydrogen production process, the economical efficiency of the process is remarkably improved by means of generation of H2 and O2 with high purity, the comprehensive cost in the process is effectively reduced, and the method has great economic benefits.

Description

Technical Field

[0001] The present invention relates to a CO 2 Methods of capture and electrochemical regeneration. Background Art

[0002] CO 2 Capture utilization and storage (CCUS) is currently one of the most effective means to achieve large-scale carbon emission reduction. 2 The capture technology has good separation effect and is mature and reliable, but it is not suitable for large-scale combustion of tail gas CO. 2 Therefore, reducing energy consumption to reduce capture costs has become a common method for solvent-based CO 2 Capture technology research hotspot.

[0003] The invention patent with patent number CN1232500C discloses "a regeneration tower heat recovery method for chemical absorption liquid regeneration". The rich liquid at the lower outlet of the self-absorption tower is split into two paths in parallel, one of which enters the solution heat exchanger and exchanges heat with the hot lean liquid at the lower outlet of the regeneration tower to recover the sensible heat in the lean liquid; the other rich liquid enters the regeneration gas heat exchanger and exchanges heat with the hot regeneration gas at the top outlet of the regeneration tower to recover the latent heat of the regeneration gas. The rich liquid leaving the solution heat exchanger and the rich liquid leaving the regeneration gas heat exchanger enter the regeneration tower for regeneration separately or combined.

[0004] The invention patent with the patent number "CN103463955A" discloses "a process for separating and recovering carbon dioxide from industrial tail gas". This process is based on the traditional carbon dioxide capture process, integrating split desorption and heat pump distillation processes, effectively utilizing the latent heat of steam at the top of the analytical tower, greatly reducing operating energy consumption, and also obtaining high-purity carbon dioxide products.

[0005] Although the above process technology can significantly reduce the energy consumption of capture, the large-scale promotion of carbon capture technology is restricted by the high energy consumption and cost of large-scale capture, and the only product of the capture process is CO 2 , which makes the added value of this process technology low and does not have better economic benefits. Summary of the invention

[0006] In order to at least partially solve the above technical problems existing in the prior art, the embodiment of the present invention provides a CO 2 Methods of capture and electrochemical regeneration to improve the overall economic efficiency of the capture process.

[0007] As one aspect of the present invention, it relates to a CO 2 A method for capture and electrochemical regeneration, the method comprising the following steps:

[0008] Use absorbent I to absorb CO in the gas source2 , obtaining an absorption rich solution; dividing the absorption rich solution into chamber I and chamber III at a volume ratio of 2:1; wherein the bottom of chamber I is connected to chamber II, and chamber II and chamber III form an electrolytic cell through an isolation material;

[0009] The chamber II and the chamber III form an electrolytic cell through an isolation material;

[0010] The absorbed rich liquid in the chamber II is electrolyzed to obtain H + , O 2 and absorbent II; the absorption rich liquid in the chamber III is electrolyzed to obtain OH - and H 2 ;

[0011] The absorption rich solution in chamber I and the H obtained by electrolysis in chamber II + Reaction to obtain CO 2 ;

[0012] The OH obtained by electrolysis in chamber III - reacting with the absorbent II in the chamber II that penetrates into the chamber III through the isolation material to obtain the absorbent I; recycling the absorbent I to absorb CO in the gas source 2 .

[0013] In one or some possible embodiments, the absorbent I is an alkaline substance, and / or contains a potassium salt or a sodium salt of a basic amino acid.

[0014] In one or some possible embodiments, the alkaline substance is selected from K 2 CO 3 , KOH, Na 2 CO 3 or one or more of NaOH;

[0015] The basic amino acids are selected from one or more of glycine, alanine, valine, leucine, isoleucine, phenylalanine, proline, tryptophan, serine, tyrosine, cysteine, methionine, asparagine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine.

[0016] In one or some possible embodiments, the basic amino acid is selected from one or more of glycine, alanine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine.

[0017] In one or some possible embodiments, the concentration of the absorbent I is 0.5-3 mol / L.

[0018] In one or some possible embodiments, in the electrolytic cell, the electrolysis temperature is 20-95° C., the electrolysis voltage is 2.0-6.3 V, and the electrolysis time is 1-72 h.

[0019] In one or some possible embodiments, the chamber II is an anode chamber, and the chamber III is a cathode chamber;

[0020] In the anode chamber, the anode electrode material is Pt or an alloy;

[0021] In the cathode chamber, the cathode electrode material is selected from Pt, Fe, graphite or alloy materials.

[0022] In one or some possible embodiments, the isolation material is selected from one of filter paper, cotton fiber, porous ceramic cotton cloth or cationic membrane.

[0023] The beneficial effects of the above technical solution provided by the embodiment of the present application include at least:

[0024] The present invention CO 2 The capture and electrochemical regeneration method realizes CO 2 Low temperature regeneration, with the help of producing higher purity H 2 and O 2 , which significantly improves the economy of the process and can effectively reduce the overall cost of the process, which is extremely economical.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 CO 2 Process flow diagram of capture and electrochemical regeneration. DETAILED DESCRIPTION

[0028] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0029] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] In the description of the present invention, it should be noted that the terms "include", "including", "have", "contain" and the like are open terms, meaning including but not limited to.

[0032] The present invention is further described below in conjunction with specific examples, and the protection scope of the present invention is not limited by the following examples. The sources of materials mainly involved in the examples are all conventional commercial products.

[0033] Refer to the attached Figure 1 , including absorption device and regeneration device; containing CO 2 The gas source reacts chemically with the lean absorption liquid in the absorption unit, CO 2 Separated from the gas source and transferred into solution. Absorbing CO 2 The rich solution is regenerated electrochemically in the regeneration unit, and the anode and cathode regions are separated by an isolation material. The regeneration process produces H 2 , and obtain CO 2 , O 2 The regenerated lean absorption liquid can be returned to the absorption unit for recycling.

[0034] Example 1

[0035] This embodiment provides a CO 2 Capture methods and electrochemical regeneration methods, including:

[0036] Use absorbent I to absorb CO in the gas source 2 , obtaining absorption rich solution;

[0037] In the embodiment of the present invention, the absorbent I may be an alkaline substance, a potassium salt or a sodium salt containing an alkaline amino acid, or a mixture of the two.

[0038] In the embodiment of the present invention, the concentration of absorbent I is 0.5-3 mol / L, including but not limited to 0.5 mol / L or 3 mol / L.

[0039] The absorbed rich liquid is diverted to chamber I and chamber III; wherein the bottom of chamber I is connected to chamber II, and chamber II and chamber III form an electrolytic cell through an isolation material;

[0040] In the embodiment of the present invention, the diversion ratio is 2:1.

[0041] In the embodiment of the present invention, the electrolysis cell has an electrolysis temperature of 20 to 95° C., an electrolysis voltage of 2.0 to 6.3 V, and an electrolysis time of 1 to 72 h.

[0042] In an embodiment of the present invention, the chamber II is an anode chamber, and the chamber III is a cathode chamber; in the anode chamber, the anode electrode material is Pt, Fe, graphite or an alloy material; in the cathode chamber, the cathode electrode material is selected from Pt, Fe, graphite or an alloy material.

[0043] In a specific embodiment, the electrode material may be the above-mentioned metal material or non-metallic corrosion-resistant material.

[0044] In an embodiment of the present invention, the isolation material is selected from one of filter paper, cotton fiber, porous ceramic cotton cloth or cationic membrane.

[0045] The absorbed rich liquid in the chamber II is electrolyzed to obtain H + , O 2 and absorbent II; the absorption rich liquid in the chamber III is electrolyzed to obtain OH - and H 2 ;

[0046] In the embodiment of the present invention, absorbent II includes but is not limited to KHCO 3 .

[0047] The absorption rich solution in chamber I and the H obtained by electrolysis in chamber II + Reaction to obtain CO 2 ;

[0048] The OH obtained by electrolysis in chamber III - reacting with the absorbent II in the chamber II that penetrates into the chamber III through the isolation material to obtain the absorbent I; recycling the absorbent I to absorb CO in the gas source 2 .

[0049] Example 2

[0050] Based on the same inventive concept, the method and some conditions of Example 1 are adopted to provide a method for capturing CO from air. 2 The specific operation of electrolytic regeneration includes:

[0051] Step 1: CO 2 absorb

[0052] At room temperature 20°C, CO 2 Air with a content of about 410 ppm was passed into an absorption device with a diameter of 5 cm and a height of 20 cm and filled with bulk fillers at a flow rate of 15 L / h. The absorbent I was a 1.5 mol / L potassium glycine solution, which was injected into the absorption device at a flow rate of 0.5 L / h, and the circulation was opened for 2 hours until the CO in the air was 2 The concentration no longer decreases, and the CO 2 absorb;

[0053] Step 2: CO 2 regeneration

[0054] The CO 2 The absorbed rich liquid is divided into chamber I, chamber II and chamber III, wherein 100 mL is added to chamber I and chamber II (the bottom of chamber I and chamber II are connected), and 50 mL is added to chamber III;

[0055] The isolation material between chamber II and chamber III is a cotton fiber filter paper, and the Pt anode and Pt cathode are placed in the anode chamber and cathode chamber respectively (chamber II is the anode chamber, and chamber III is the cathode chamber). A constant current electrolysis of 30 mA is passed between the anode and the cathode, and the corresponding voltage is about 2.5-3.8 V. The electrolysis is continued for 3 hours. During the electrolysis process, the rotor is continuously stirred at a rate of 200 rpm to make the liquid composition in chambers I, II and III uniform. At the same time, 0.8 L / h of N is passed into chambers I, II and III respectively. 2 , and then connect the corresponding CO 2 , O 2 , H 2 Analyzer;

[0056] The data from the analyzer show that during the electrolysis experiment, a peristaltic pump was used to pass about 10 ml of the electrolyte solution in chamber III into the absorption device every hour. The absorption process was related to the CO 2 React and control CO in gas 2 The removal rate is 75%. After the solution comes out of the absorption device, 10 mL of electrolyte solution is passed into chamber I using a peristaltic pump to continue the electrolysis reaction;

[0057] After the electrolysis experiment was carried out for 1 hour, the pH value of the anode chamber solution was measured to be 1.9, and the pH value of the cathode chamber solution was 12.3. At this time, the gas concentrations corresponding to the three chambers were 1.2% CO 2 , 1.3% O 2 , 2.5% H 2 ;

[0058] During the electrolysis experiment, about 10 ml of the electrolyte solution in chamber III was passed into the absorption device using a peristaltic pump every hour, and then 10 ml of the electrolyte solution in the absorption device was passed into chamber I using a peristaltic pump to continue the electrolysis reaction;

[0059] The solution entering the absorption device continues to absorb CO 2 Repeat the above process until the liquid level in chambers Ⅰ, Ⅱ and Ⅲ drops to the upper edge of the isolation material in chambers Ⅱ and Ⅲ, and the reaction ends. When the reaction ends, CO is measured. 2 The regeneration rate is 90%.

[0060] Therefore, the present invention CO 2 The capture and electrochemical regeneration method realizes CO 2 Low temperature regeneration, with the help of producing higher purity H 2 and O 2 , which significantly improves the economy of the process and can effectively reduce the overall cost of the process, which is extremely economical.

[0061] Although the description of the present invention has been quite detailed and has been described in particular with respect to several described embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, so as to effectively cover the intended scope of the present invention. In addition, the present invention is described above with the embodiments foreseeable by the inventors, and its purpose is to provide a useful description, and those non-substantial changes to the present invention that are not currently foreseen may still represent equivalent changes of the present invention.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0063] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for CO2 capture and electrochemical regeneration, characterized in that: The method comprises the following steps: Adopt absorbent I to absorb CO2 in the gas source to obtain absorption rich liquid; divide the absorption rich liquid into chamber I and chamber III; wherein the bottom of chamber I is connected to chamber II, and chamber II and chamber III form an electrolytic cell through an isolation material; The absorbed rich liquid in the chamber II is electrolyzed to obtain H + , O2 and absorbent II; the absorption rich liquid in the chamber III is electrolyzed to obtain OH - and H2; The absorption rich solution in chamber I and the H obtained by electrolysis in chamber II + Reaction to obtain CO2; The OH obtained by electrolysis in chamber III - The absorbent I is obtained by reacting with the absorbent II in the chamber II that permeates into the chamber III through the isolation material; and the absorbent I is circulated to absorb CO2 in the gas source.

2. The method according to claim 1, characterized in that The absorbent I is an alkaline substance and / or a potassium salt or sodium salt containing an alkaline amino acid.

3. The method according to claim 2, characterized in that The alkaline substance is selected from one or more of K2CO3, KOH, Na2CO3 or NaOH; The basic amino acids are selected from one or more of glycine, alanine, valine, leucine, isoleucine, phenylalanine, proline, tryptophan, serine, tyrosine, cysteine, methionine, asparagine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine.

4. The method according to claim 3, characterized in that The basic amino acid is selected from one or more of glycine, alanine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine.

5. The method according to claim 1 or 2, characterized in that: The concentration of the absorbent I is 0.5-3 mol / L.

6. The method according to claim 1, characterized in that In the electrolytic cell, the electrolysis temperature is 20-95° C., the electrolysis voltage is 2.0-6.3 V, and the electrolysis time is 1-72 h.

7. The method according to claim 6, characterized in that The chamber II is the anode chamber, and the chamber III is the cathode chamber; In the anode chamber, the anode electrode material is Pt, Fe, graphite or alloy material; In the cathode chamber, the cathode electrode material is selected from Pt, Fe, graphite or alloy materials.

8. The method according to claim 1, characterized in that The isolation material is selected from one of filter paper, cotton fiber, porous ceramic cotton cloth or cationic membrane.

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