Method for preparing cement precursor and capturing CO2 based on electrochemical method

Abstract

The invention relates to a method for preparing a cement precursor and capturing CO2 on the basis of an electrochemical process, which comprises the following steps: connecting the anode of a primary battery with the cathode of the primary battery, connecting the cathode of an electrolytic cell with the anode of the primary battery, electrolyzing CaCO3 by using the electrolytic cell, generating a cement precursor Ca (OH) 2 in a first intermediate chamber, meanwhile, mixed gas of O2 and CO2 generated by the anode of the electrolytic tank and H2 generated by the cathode of the electrolytic tank are led to a primary battery through a gas pipeline, CO2 generated by the second middle cavity is captured, the device can generate a cement precursor Ca (OH) 2 and capture CO2 at the same time, and the captured CO2 can generate electric energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemistry, in particular to a method for preparing cement precursor and capturing CO2 based on electrochemical method. BACKGROUND

[0002] The electrochemical method driven by renewable electricity to convert calcium carbonate into cement clinker precursor calcium hydroxide represents an important technical direction for the low-carbon transformation of the cement industry. The core of this process is to directly decompose calcium carbonate through electrochemical reaction, avoiding the large consumption of fossil fuels and direct carbon emissions in the traditional limestone calcination process.

[0003] However, the electrochemical process itself has an inherent key problem in achieving the carbon reduction goal: while efficiently generating and separating high-purity Ca(OH)2, it is difficult to systematically capture the carbon dioxide gas inevitably associated with the reaction, and effectively utilize the byproduct hydrogen energy produced simultaneously, to achieve energy optimization and true carbon closed loop of the entire process.

[0004] Specifically, in the process of electrochemical decomposition of calcium carbonate: the anode reaction inevitably releases CO2 gas, calcium carbonate is oxidized and decomposed at the anode, inevitably producing carbon dioxide gas (usually mixed with oxygen). If this part of CO2 is directly discharged without treatment, it fundamentally undermines the carbon reduction value of the process. The cathode reaction produces hydrogen gas, water is reduced at the cathode to produce hydrogen gas, which is a byproduct containing chemical energy. Its energy value is usually not effectively captured and utilized in the existing separation reaction system, making it difficult to further reduce the energy consumption of the overall process. Lack of collaborative processing mechanism: existing technical solutions mainly focus on how to improve the generation efficiency or purity of Ca(OH)2, and fail to provide an integrated solution to co-convert and process the CO2-containing gas produced at the anode and the H2 produced at the cathode.

[0005] Therefore, developing a new type of electrochemical device and method that can integrally achieve efficient preparation / separation of cement precursor Ca(OH)2, simultaneous capture of associated CO2, and utilization of byproduct H2 chemical energy to generate useful electric energy is crucial for promoting the industrial application of this technology and achieving near-zero emissions in the cement production process. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a method for preparing cement precursor and capturing CO2 based on electrochemical method.

[0007] The technical scheme of the present application is as follows: A method for preparing cement precursor and capturing CO2 based on electrochemical method, comprising the following steps: The electrolytic cell and the primary cell are provided, the anode of the electrolytic cell is connected with the cathode of the primary cell, and the cathode of the electrolytic cell is connected with the anode of the primary cell; A first reaction solution is injected into the electrolytic cell, and a second reaction solution is injected into the primary cell; The electrolytic cell is powered, the electrolytic cell reacts to generate a cement precursor under power, the anode reaction of the electrolytic cell produces a carbon-containing mixed gas, and the cathode reaction of the electrolytic cell produces hydrogen gas; The carbon-containing mixed gas is introduced into the cathode of the primary cell, the hydrogen gas is introduced into the anode of the primary cell, and the primary cell reacts under catalysis to produce carbon dioxide gas and collect it.

[0008] Further, the electrolytic cell comprises a first anode chamber, a first cathode chamber and a first intermediate chamber between the two separated by an ion exchange membrane, the first reaction solution comprises a soluble calcium salt solution and a calcium carbonate source injected into the first anode chamber, an alkaline metal hydroxide solution injected into the first cathode chamber and a soluble potassium salt solution injected into the first intermediate chamber.

[0009] Further, the soluble calcium salt solution is a saturated CaCl2 solution or a saturated Ca(NO3)2 solution, the calcium carbonate source is CaCO3, the alkaline metal hydroxide solution is a KOH solution, and the soluble potassium salt solution is a saturated KNO3 solution or a saturated KCl solution.

[0010] Further, the primary cell comprises a second anode chamber, a second cathode chamber and a second intermediate chamber between the two separated by an ion exchange membrane, the second reaction solution comprises a soluble calcium salt solution injected into the second anode chamber, an alkaline metal hydroxide solution injected into the second cathode chamber and water injected into the second intermediate chamber.

[0011] Further, the soluble calcium salt solution is a saturated CaCl2 solution or a saturated Ca(NO3)2 solution, and the alkaline metal hydroxide solution is a KOH solution.

[0012] Further, the carbon-containing mixed gas reacts to form carbonate ions at the cathode of the primary cell, and the hydrogen gas is oxidized to hydrogen ions at the anode of the primary cell, and the carbonate ions and the hydrogen ions react to produce carbon dioxide and water.

[0013] Further, an anode electrode is arranged in the second anode chamber, and a cathode electrode is arranged in the second cathode chamber, and a Pt / C catalyst is fixed on the surfaces of the anode electrode and the cathode electrode.

[0014] Further, the peak power of the primary cell is 9 mW / cm 2 .

[0015] Further, the maximum rate of CO2 capture of the original battery is 0.25 kg / (h·m 2 ).

[0016] Further, the maximum current density of the original battery is 60 mA / cm 2 .

[0017] Compared with the prior art, the present application has at least the following advantages: The present application relates to a method for preparing cement precursor and capturing CO2 based on electrochemical method, connecting the anode of the original battery with the cathode of the original battery, connecting the cathode of the electrolytic cell with the anode of the original battery, the electrolytic cell is used for electrolyzing CaCO3, the first intermediate chamber generates cement precursor Ca(OH)2, and the mixed gas of O2 and CO2 generated by the anode of the electrolytic cell and H2 generated by the cathode of the electrolytic cell are connected to the original battery through the gas pipeline, the second intermediate chamber generates CO2 which is captured, the device of the present application can generate cement precursor Ca(OH)2 and capture CO2 at the same time, and the captured CO2 can generate electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present application, the drawings required in the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn according to the actual proportion.

[0019] Figure 1 It is a structural schematic diagram of the device for preparing cement precursor and capturing CO2 based on electrochemical method of the present application; Figure 2 It is a monitoring diagram of the operating voltage stability of the original battery of test example one of the present application; Figure 3 It is an XRD characterization diagram of the product in the intermediate chamber of the electrolytic cell of test example two of the present application; Figure 4 It is a gas chromatogram of the purity analysis of the collected CO2 gas of test example three of the present application; Figure 5 It is a polarization curve diagram of the original battery of test example four of the present application; Figure 6 It is a diagram of the relationship between CO2 capture rate and current efficiency under different current densities of test example four of the present application.

[0020] Explanation of reference signs: electrolytic cell 1, first anode chamber 2, first cathode chamber 3, first intermediate chamber 4, first cation exchange membrane 5, first anion exchange membrane 6, original battery 7, second anode chamber 8, second cathode chamber 9, second intermediate chamber 10, second cation exchange membrane 11, second anion exchange membrane 12. DETAILED DESCRIPTION

[0021] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without some or all of these details under appropriate circumstances. The purpose of the above detailed description of the specific embodiments of the present application is to illustrate the application by examples.

[0022] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. The terms "comprises" and / or "comprising," or "includes" and / or "including" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0024] A method for preparing cement precursor and capturing CO2 by electrochemistry, comprising the following steps: providing an electrolytic cell 1 and a primary cell 7, connecting the anode of the electrolytic cell 1 with the cathode of the primary cell 7, connecting the cathode of the electrolytic cell 1 with the anode of the primary cell 7; injecting a first reaction solution into the electrolytic cell 1, and injecting a second reaction solution into the primary cell 7; powering the electrolytic cell 1, the electrolytic cell 1 generates cement precursor under the reaction of power, the anode reaction of the electrolytic cell 1 produces carbon-containing mixed gas, and the cathode reaction of the electrolytic cell 1 produces hydrogen; the carbon-containing mixed gas is introduced into the cathode of the primary cell 7, and the hydrogen is introduced into the anode of the primary cell 7, the primary cell 7 produces carbon dioxide gas under the catalytic action and collects.

[0025] The electrolytic cell 1 comprises a first anode chamber 2, a first cathode chamber 3 and a first intermediate chamber 4 between the two, separated by an ion exchange membrane, a first cation exchange membrane 5 is arranged between the first anode chamber 2 and the first intermediate chamber 4, a first anion exchange membrane 6 is arranged between the first cathode chamber 3 and the first intermediate chamber 4, and the first reaction solution comprises a soluble calcium salt solution injected into the first anode chamber 2 and a calcium source carbonate, an alkaline metal hydroxide solution injected into the first cathode chamber 3, and a soluble potassium salt solution injected into the first intermediate chamber 4. The soluble calcium salt solution is a saturated CaCl2 solution or a saturated Ca(NO3)2 solution, the calcium source carbonate is CaCO3, the alkaline metal hydroxide solution is a KOH solution, and the soluble potassium salt solution is a saturated KNO3 solution or a saturated KCl solution.

[0026] The primary cell 7 comprises a second anode chamber 8, a second cathode chamber 9 and a second intermediate chamber 10 between the two, separated by an ion exchange membrane, a second cation exchange membrane 11 is arranged between the second anode chamber 8 and the second intermediate chamber 10, and a second anion exchange membrane 12 is arranged between the second cathode chamber 9 and the second intermediate chamber 10. In this embodiment, the second cation exchange membrane 11 is Nafion117, and the second anion exchange membrane 12 is SustainionX37. The second reaction solution comprises a soluble calcium salt solution injected into the second anode chamber 8, an alkaline metal hydroxide solution injected into the second cathode chamber 9, and water injected into the second intermediate chamber 10. The soluble calcium salt solution is a saturated CaCl2 solution or a saturated Ca(NO3)2 solution, and the alkaline metal hydroxide solution is a KOH solution.

[0027] The second anode chamber 8 is provided with an anode electrode, and the second cathode chamber 9 is provided with a cathode electrode. Pt / C catalyst is fixed on the surface of the anode electrode and the cathode electrode.

[0028] The working principle of the preparation of cement precursors and the capture of CO2 based on the electrochemical method is as follows: The electrolyte in the first anode chamber 2 of the electrolytic cell 1 is a saturated CaCl2 suspension, and the suspended solid component is CaCO3. The reactions occurring are shown in equations (1) and (2). It can be seen that in the first anode chamber 2, a mixed gas with a ratio of O2 to CO2 of 1:2 will be produced, and Ca 2+ Pass through the first cation exchange membrane 5 into the first intermediate chamber 4.

[0029] The electrolyte in the first cathode chamber 3 of the electrolytic cell 1 is a 1 mol / L KOH solution. The reaction occurring is shown in equation (3). It can be seen that in the first cathode chamber 3, H2 and OH- It enters the first intermediate chamber 4 after passing through the first anion exchange membrane 6.

[0030] The solution in the first intermediate chamber 4 of the electrolytic cell 1 is a saturated KNO3 solution, and the reaction that occurs is shown in equation (4). The precipitate Ca(OH)2 generated in the first intermediate chamber 4 is collected and dried.

[0031] The electrolyte in the second cathode chamber 9 of the galvanic cell 7 is a 1 mol / L KOH solution. A Pt / C catalyst is fixed on the surface of the cathode electrode. A mixture of CO2 and O2 obtained from the previous reaction is introduced into the second cathode chamber 9. The reactions that occur are shown in equations (5) and (6). CO3 is generated in the second cathode chamber 9. 2- Ions, CO3 2- It passes through the second anion exchange membrane 12 and enters the second intermediate chamber 10.

[0032] The electrolyte in the second anode chamber 8 of the galvanic cell 7 is saturated Ca(NO3)2. A Pt / C catalyst is fixed on the surface of the anode electrode. H2 obtained from the previous reaction is introduced into the second anode chamber 8. The reaction that occurs is shown in equation (7). It can be seen that the introduced H2 will be oxidized to H in the second anode chamber 8. + H + It enters the second intermediate chamber 10 after passing through the second cation exchange membrane 11.

[0033] Pure water is circulated into the second intermediate chamber 10 of the galvanic cell 7, and the reaction that occurs is shown in equation (8). CO2 is generated in the intermediate chamber and collected by the gas collection device.

[0034] Test Example 1 Figure 2 To monitor the cell voltage of galvanic cell 7 during operation using an electrochemical workstation, at a voltage of 100 mA / cm², 2 Under the operating conditions, the voltage was continuously operated for 150 minutes, and as can be seen from the figure, the voltage exhibited good stability.

[0035] Test Example 2: Analysis of Ca(OH)2 products from the electrolytic cell Figure 3The image shows the XRD characterization of the product in the intermediate cavity of the electrolytic cell after the reaction. As can be seen from the image, 18.0°, 28.7°, 34.1°, 47.1°, 50.8°, 54.4° and 64.2° all correspond to the characteristic peaks of calcium hydroxide, and are consistent with the standard diffraction peaks of calcium hydroxide (JCPDS No. 44-1481). No other crystalline phase characteristic peaks were detected, indicating that a high-purity cement clinker precursor Ca(OH)2 was successfully prepared.

[0036] Purity analysis of CO2 prepared in Test Example 3 CO2 capture process: A mixture of O2 and CO2 gas, already generated, is pumped into the cathode of galvanic cell 7; H2 gas is pumped into the anode. The intermediate chamber is filled with solid electrolyte and purified water is pumped in. The CO2 generated in the intermediate chamber is collected through a gas bag. During the reaction, CO2 is continuously discharged from the pipes along with the water flow. The maximum output power of the battery is set to 30 mA / cm². 2 The CO2 gas produced under these conditions was collected and analyzed using a gas chromatograph. The results are as follows: Figure 4 As shown in the FID peak diagram, there is only one CO2 main peak. The peak area was calculated and compared with the peak area of ​​pure CO2 gas. The calculated purity of CO2 is over 98%.

[0037] Test Example 4: Primary Battery Performance Test This test example uses a fuel cell tester to measure the voltage of the primary cell 7 reaction at different current densities, obtaining the cell's polarization curve and the CO2 capture rate and current density at different current densities. Figure 5 The curve shows that the open-circuit voltage is 1.08V and the short-circuit current can reach 60mA / cm. 2 Peak power can reach 9mW / cm 2 The efficiency and rate of CO2 capture current at different current densities are as follows: Figure 6 As shown, to maximize efficiency, the CO2 capture rate is 0.25 kg / (h·m²) under the condition that the battery reaches its peak power. 2 The current efficiency is around 90%, while the current rate of Direct Air Capture (DAC) technology is approximately 0.041 kg / (h·m). 2 This means that the CO2 capture rate of this technology is more than 6 times that of the others.

[0038] The above examples are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.

Claims

1. A method for preparing cement precursors and capturing CO2 based on an electrochemical method, characterized in that, Includes the following steps: An electrolytic cell (1) and a galvanic cell (7) are provided, the anode of the electrolytic cell (1) is connected to the cathode of the galvanic cell (7), and the cathode of the electrolytic cell (1) is connected to the anode of the galvanic cell (7). The first reaction solution is injected into the electrolytic cell (1), and the second reaction solution is injected into the galvanic cell (7); When the electrolytic cell (1) is energized, the electrolytic cell (1) reacts under the energization to generate cement precursor. The anode reaction of the electrolytic cell (1) generates a carbon-containing mixed gas, and the cathode reaction of the electrolytic cell (1) generates hydrogen. The carbon-containing mixed gas is introduced into the cathode of the galvanic cell (7), and the hydrogen gas is introduced into the anode of the galvanic cell (7). The galvanic cell (7) reacts under catalysis to produce carbon dioxide gas, which is then collected.

2. The method according to claim 1, characterized in that, The electrolytic cell (1) includes a first anode chamber (2), a first cathode chamber (3), and a first intermediate chamber (4) between them, separated by an ion exchange membrane. The first reaction solution includes a soluble calcium salt solution and a calcium source carbonate injected into the first anode chamber (2), an alkaline metal hydroxide solution injected into the first cathode chamber (3), and a soluble potassium salt solution injected into the first intermediate chamber (4).

3. The method according to claim 2, characterized in that, The soluble calcium salt solution is a saturated CaCl2 solution or a saturated Ca(NO3)2 solution, the calcium source carbonate is CaCO3, the alkaline metal hydroxide solution is a KOH solution, and the soluble potassium salt solution is a saturated KNO3 solution or a saturated KCl solution.

4. The method according to claim 1, characterized in that, The galvanic cell (7) includes a second anode chamber (8), a second cathode chamber (9), and a second intermediate chamber (10) between them, separated by an ion exchange membrane. The second reaction solution includes a soluble calcium salt solution injected into the second anode chamber (8), an alkaline metal hydroxide solution injected into the second cathode chamber (9), and water injected into the second intermediate chamber (10).

5. The method according to claim 4, characterized in that, The soluble calcium salt solution is a saturated CaCl2 solution or a saturated Ca(NO3)2 solution, and the alkaline metal hydroxide solution is a KOH solution.

6. The method according to claim 5, characterized in that, The carbon-containing mixed gas reacts at the cathode of the galvanic cell (7) to form carbonate ions, and the hydrogen gas is oxidized at the anode of the galvanic cell (7) to form hydrogen ions. The carbonate ions and the hydrogen ions react to produce carbon dioxide and water.

7. The method according to claim 5, characterized in that, An anode electrode is provided in the second anode chamber (8), and a cathode electrode is provided in the second cathode chamber (9). A Pt / C catalyst is fixed on the surface of the anode electrode and the cathode electrode.

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