Carbon dioxide capture method, capture system and application thereof

Abstract

The application discloses a carbon dioxide capturing method, a capturing system and application thereof. The method comprises the following steps: mixing potassium carbonate solution and carbon dioxide gas to obtain a suspension, filtering the suspension to obtain a filtrate; after the battery device is powered on, the filtrate is introduced into a cathode area of the battery device, and carbon dioxide gas is introduced into the cathode area; after the solution in the cathode area is heated and the carbon dioxide is separated, the solution is introduced into an anode area of the battery device. The carbon dioxide capturing method provided by the application can generate electric energy while capturing carbon dioxide by using a battery device, carbon dioxide gas is introduced into the cathode area of the battery device to capture the carbon dioxide, after power on, K2CO3 is used as a reaction raw material of the anode area, the output power of the battery and the conversion rate of CO2 are high, the maximum power density can reach 50 W / m 2 , and the CO2 conversion rate can reach more than 24%.

Description

Technical Field

[0001] This invention relates to the field of environmental protection, specifically to a carbon dioxide capture method, capture system, and its application. Background Technology

[0002] Currently, global warming is an indisputable fact, and the emission of the greenhouse gas carbon dioxide is one of the main factors contributing to global warming. Conventional carbon dioxide emission reduction methods include carbon dioxide capture and storage (CCS) technology, which involves capturing carbon dioxide and then injecting it into underground reservoirs for long-term storage.

[0003] Depending on the application and the pressure of the feed gas, carbon dioxide capture methods are divided into dry capture and wet capture. Dry capture includes adsorption and membrane methods, which are generally suitable for applications with low carbon dioxide concentrations. Wet capture includes chemical absorption and physical absorption methods. Chemical absorption is mostly used for applications with relatively low feed gas pressure or at atmospheric pressure.

[0004] CN104275072A discloses a method for capturing CO2 using a chemical-physical composite absorbent. The technical solution includes conventional absorption and heating desorption processes for CO2 capture and separation, absorption and vacuum desorption processes, absorption and inert gas stripping processes, or processes that simultaneously absorb and separate SO2, H2S, and / or organic sulfur while capturing or separating CO2. The chemical-physical composite absorbent for capturing CO2 comprises, by weight percentage, 15-45% hydroxyethyl ethylenediamine, 10-30% sulfolane, and the remainder being water and other components, including 1% commonly used corrosion inhibitors and antioxidants. The absorption temperature is 30℃-80℃, the absorption pressure is 0.05-0.15 MPa, the desorption temperature is 80℃-130℃, and the desorption pressure is 0.1-0.2 MPa. This method improves the solubility of CO2 in the absorption-desorption cycle, reduces the heat of vaporization of water, and lowers the energy consumption and cost of CO2 capture.

[0005] This invention aims to capture carbon dioxide greenhouse gas in the atmosphere and simultaneously utilize the capture process for mineralization and power generation. Summary of the Invention

[0006] To address the aforementioned problems in existing technologies, this invention provides a carbon dioxide capture method, a capture system, and its application. The carbon dioxide capture method provided by this invention can generate electricity while capturing carbon dioxide, utilizing potassium carbonate (K₂CO₃) to provide carbonate ions to the anode region of the battery device. - Ions (CO3) 2- After carbon dioxide is enriched in the cathode region, it reacts to produce bicarbonate (HCO3-). - HCO3 -K provided by K2CO3 + Potassium bicarbonate (KHCO3) is further generated. The CO2 and K2CO3 generated after heating and decomposing KHCO3 can be used as reaction raw materials in the anodizing and anodic regions, respectively, to realize the recycling of products and reactants. Moreover, the maximum power density of the electrical energy generated by this invention is relatively high, and the conversion rate of CO2 is relatively high.

[0007] The first aspect of the present invention provides a carbon dioxide capture method, the method comprising:

[0008] Step A: Mix potassium carbonate solution and carbon dioxide gas to obtain a suspension, and then filter the suspension to obtain a filtrate.

[0009] Step B: After the battery device is powered on, the filtrate is introduced into the cathode region of the battery device, and carbon dioxide gas is introduced into the cathode region.

[0010] Step C: After the solution in the cathode region is heated and carbon dioxide is separated, it is then introduced into the anode region of the battery device.

[0011] This invention utilizes a battery device to capture carbon dioxide while simultaneously generating electrical energy. Specifically, carbon dioxide gas is introduced into the cathode region of the battery device for enrichment, and upon energization, the carbon dioxide is converted into HCO3. - It can react with K in the filtrate + KHCO3 is generated, and the CO2 and K2CO3 produced after heating and decomposition of KHCO3 can be used as reaction raw materials in the cathode and anode regions, respectively, to achieve material recycling. Moreover, K2CO3 and KHCO3 have high solubility, which can improve the battery output power and CO2 conversion rate. Furthermore, since the requirements for the reaction raw materials of the battery device are low, this invention can greatly expand the source of raw materials.

[0012] In some embodiments of the carbon dioxide capture method according to the present invention, the cathode electrode of the battery device is selected from a carbon cloth electrode. Preferably, the cathode electrode is a carbon cloth supported electrode, and the supported element is selected from at least one of platinum, palladium, and nickel.

[0013] In some embodiments of the carbon dioxide capture method according to the present invention, the anode electrode is selected from a porous membrane gas diffusion electrode. Preferably, the anode electrode is a hydrogen diffusion electrode.

[0014] According to some embodiments of the carbon dioxide capture method of the present invention, the battery device is provided with a cation exchange membrane that divides the battery device into the anode region and the cathode region.

[0015] According to some embodiments of the carbon dioxide capture method of the present invention, in step A, the concentration of the potassium carbonate solution is 0.5 to 10 mol / L, and carbon dioxide gas is bubbled into the potassium carbonate solution at a rate of 0.01 to 2 L / min to obtain the suspension.

[0016] According to some embodiments of the carbon dioxide capture method of the present invention, step A further includes: stirring the suspension before performing the filtration process.

[0017] According to some embodiments of the carbon dioxide capture method of the present invention, in step A, the conditions of the stirring process include: a stirring speed of 50 to 1000 rpm and a stirring time of 1 to 60 min.

[0018] According to some embodiments of the carbon dioxide capture method of the present invention, in step B, the rate at which the carbon dioxide gas is introduced into the cathode region is 0.01 to 2 L / min.

[0019] According to some embodiments of the carbon dioxide capture method of the present invention, step C is followed by: passing the solution in the anode region into the cathode region.

[0020] According to some embodiments of the carbon dioxide capture method of the present invention, after step C, the method further includes: the solution in the cathode region is heated and carbon dioxide is separated, and then introduced into the anode region of the battery device, wherein the main component of the solution is K2CO3, and while the solution is circulating in the anode region, the solution after the reaction at the anode electrode is drawn into the cathode region for circulation at a rate of 5 to 1000 mL / min.

[0021] According to some embodiments of the carbon dioxide capture method of the present invention, in step C, the solution is drawn from the cathode region at a rate of 5 to 1000 mL / min for the heating treatment.

[0022] According to some embodiments of the carbon dioxide capture method of the present invention, step A further includes: the filtrate is circulated between the filtrate storage device and the cathode zone at a rate of 5 to 1000 mL / min.

[0023] In the battery device of the present invention, while capturing CO2 with conventional K2CO3 solution, a certain amount of electrical energy can be generated, greatly improving the practicality and economy of the capture process. The overall chemical reaction process occurring in the battery device is shown in equation (1) below:

[0024] CO2 + K2CO3 + H2O = 2KHCO3 + electrical energy (1)

[0025] Specifically, the main chemical reactions occurring inside the battery device are shown in equations (2) and (3) below:

[0026] Cathode region: 2CO2 + 2H2O + 2K + +2e - →2KHCO3+H2 (2)

[0027] Anode region: 2K₂CO₃ + H₂ → 2KHCO₃ + 2K + +2e - (3)

[0028] In the cathode region of the battery device, CO2 and H2O react to form HCO3. - and H + HCO3 - Further with K passing through the cation exchange membrane via the anode region + The reaction yields KHCO3 and H2O. + At the cathode electrode, H2 combines with electrons and is reduced to H2. The H2 generated at the cathode then cycles back to the anode region and, under the influence of the anode electrode, loses electrons and is oxidized to H2. + H + It then reacts with K2CO3 in the anode region to produce KHCO3 and K + K + The reaction proceeds through the cation exchange membrane into the cathode region. The KHCO3 generated in the anode and cathode regions, after being decomposed by heating, yields CO2 and K2CO3, which can then be used as reaction feedstocks in the cathode and anode regions, respectively, thus achieving a recycling process.

[0029] The carbon dioxide capture method provided by this invention has a wide range of raw material sources, which can greatly expand its application scope. Furthermore, both K₂CO₃ and KHCO₃ have high solubility, which can improve the battery's output power and CO₂ conversion rate. The maximum power density can reach 50 W / m³. 2 The CO2 conversion rate can reach over 24%.

[0030] A second aspect of the present invention provides a carbon dioxide capture system for the above-described capture method, the system comprising the battery device, a filtrate storage device, and a circulation device, the circulation device being capable of circulating the filtrate between the filtrate storage device and the cathode region of the battery device.

[0031] A third aspect of the present invention provides an application of the above-described carbon dioxide capture method or carbon dioxide capture system in carbon dioxide capture.

[0032] The beneficial effects of this invention are:

[0033] The carbon dioxide capture method provided by this invention utilizes a battery device to capture carbon dioxide while simultaneously generating electrical energy. Carbon dioxide gas is introduced into the cathode region of the battery device for capture, and after energization, K2CO3 serves as the reaction material in the anode region, where carbon dioxide reacts to form HCO3. - It can react with K in the filtrate + KHCO3 is generated, and the CO2 and K2CO3 produced after heating and decomposition of KHCO3 can be used as reaction raw materials in the cathode and anode regions, respectively, realizing the recycling of materials. Furthermore, both K2CO3 and KHCO3 have high solubility, which can improve the battery's output power and CO2 conversion rate, with a maximum power density reaching 50 W / m³. 2 The CO2 conversion rate can reach over 24%.

[0034] The battery device in this invention has low requirements for the reaction raw materials, which greatly expands the source of raw materials, making the carbon dioxide capture method of this invention applicable to most application environments. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the battery device and its internal reaction provided in Embodiment 1 of the present invention.

[0036] Figure 2 This is a schematic flowchart of the carbon dioxide capture process provided in Embodiment 1 of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Anode electrode; 2. Cation exchange membrane; 3. Cathode electrode; Detailed Implementation

[0039] To make the present invention easier to understand, the present invention will be described in detail below with reference to the embodiments and accompanying drawings. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0040] The testing method and equipment used in this invention are as follows:

[0041] (1) The carbon dioxide conversion rate was calculated by measuring the concentration of CO2 in the gas stream. The CO2 concentration analyzer was purchased from Beijing Huayun Instrument Co., Ltd., model GXH-3011 online infrared gas analyzer.

[0042] (2) The hydrogen diffusion electrode was a Pt305 model purchased from Tianjin Aida Hengsheng Company.

[0043] (3) The platinum-supported Pt / C electrode on carbon cloth was GC0101, purchased from Tianjin Aida Hengsheng Company.

[0044] (4) The cation exchange membrane was purchased from Merck's Nafion 117 model.

[0045] All other reagents are available commercially.

[0046]

Example 1

[0047] In this embodiment, K2CO3 is used as an alkaline absorbent to capture CO2 in the original flue gas and generate electricity. Figure 1 As shown, in the housing of the CO2 capture battery device, a cation exchange membrane 2, which allows only cations to pass through but blocks anions, divides the device into an anode region and a cathode region. A hydrogen diffusion electrode is used as the anode electrode 1, and a carbon cloth-supported Pt / C electrode is used as the cathode electrode 3.

[0048] Prepare 200 mL of a 2 mol / L K₂CO₃ solution. Gradually bubble CO₂-containing flue gas into the K₂CO₃ solution at a rate of 20 mL / min to form a suspension. Stir at 300 rpm for 20 min, then filter the suspension. Circulate the filtrate between the filtrate storage device and the cathode zone at a rate of 20 mL / min. Simultaneously, the CO₂-containing flue gas is bubbled into the cathode zone at a rate of 20 mL / min. The solution is extracted from the cathode zone at a rate of 20 mL / min. After being regenerated by heating at 100°C to separate CO₂, the solution is condensed to room temperature and then introduced into the anode zone. When the solution accumulates to 100 mL in the anode zone, while the solution is circulating in the anode zone, it is simultaneously extracted at a rate of 20 mL / min and sent to the cathode zone to form a circulation system.

[0049] like Figure 2 As shown, in this embodiment, the raw flue gas containing CO2 is processed... Figure 1 The battery device shown captures CO2 and generates electricity, then emits the remaining waste gas. The potassium bicarbonate produced during the capture and power generation process is heated to obtain CO2 and K2CO3, thus achieving regeneration. CO2 and K2CO3 are then used as reactants in the cathode and anode regions of the battery device, respectively.

[0050] A power load is connected between the cathode and anode, and the output power is adjusted by controlling the resistance of the power load. At 25°C, the current is set to increase from 0mA to the maximum output current at a rate of 2mA / s. Under these conditions, the maximum battery voltage is measured to be 0.6V, and the maximum power density is 50W / m³. 2 The CO2 conversion rate is 24%.

[0051]

Example 2

[0052] In this embodiment, K2CO3 is used as an alkaline absorbent to capture CO2 in the original flue gas and generate electricity. Figure 1As shown, in the housing of the CO2 capture battery device, a cation exchange membrane 2, which allows only cations to pass through but blocks anions, divides the device into an anode region and a cathode region. A hydrogen diffusion electrode is used as the anode electrode 1, and a carbon cloth-supported Pd / C electrode is used as the cathode electrode 3.

[0053] Prepare 200 mL of a 2 mol / L K₂CO₃ solution. Gradually bubble CO₂-containing flue gas into the K₂CO₃ solution at a rate of 20 mL / min to form a suspension. Stir at 300 rpm for 20 min, then filter the suspension. Circulate the filtrate between the filtrate storage device and the cathode zone at a rate of 20 mL / min. Simultaneously, the CO₂-containing flue gas is bubbled into the cathode zone at a rate of 20 mL / min. The solution is extracted from the cathode zone at a rate of 20 mL / min. After being regenerated by heating at 100°C to separate CO₂, the solution is condensed to room temperature and then introduced into the anode zone. When the solution accumulates to 100 mL in the anode zone, while the solution is circulating in the anode zone, it is simultaneously extracted at a rate of 20 mL / min and sent to the cathode zone to form a circulation system.

[0054] like Figure 2 As shown, in this embodiment, the raw flue gas containing CO2 is processed... Figure 1 The battery device shown captures CO2 and generates electricity, then emits the remaining waste gas. The potassium bicarbonate produced during the capture and power generation process is heated to obtain CO2 and K2CO3, thus achieving regeneration. CO2 and K2CO3 are then used as reactants in the cathode and anode regions of the battery device, respectively.

[0055] A power load is connected between the cathode and anode, and the output power is adjusted by controlling the resistance of the power load. At 25°C, the current is set to increase from 0mA to the maximum output current at a rate of 2mA / s. Under these conditions, the maximum battery voltage is measured to be 0.58V, and the maximum power density is 47W / m³. 2 The CO2 conversion rate is 23%.

[0056]

Example 3

[0057] In this embodiment, K2CO3 is used as an alkaline absorbent to capture CO2 in the original flue gas and generate electricity. Figure 1 As shown, in the housing of the CO2 capture battery device, a cation exchange membrane 2, which allows only cations to pass through but blocks anions, divides the device into an anode region and a cathode region. A hydrogen diffusion electrode is used as the anode electrode 1, and a carbon cloth-supported Ni / C electrode is used as the cathode electrode 3.

[0058] Prepare 200 mL of a 2 mol / L K₂CO₃ solution. Gradually bubble CO₂-containing flue gas into the K₂CO₃ solution at a rate of 20 mL / min to form a suspension. Stir at 300 rpm for 20 min, then filter the suspension. Circulate the filtrate between the filtrate storage device and the cathode zone at a rate of 20 mL / min. Simultaneously, the CO₂-containing flue gas is bubbled into the cathode zone at a rate of 20 mL / min. The solution is extracted from the cathode zone at a rate of 20 mL / min. After being regenerated by heating at 100°C to separate CO₂, the solution is condensed to room temperature and then introduced into the anode zone. When the solution accumulates to 100 mL in the anode zone, while the solution is circulating in the anode zone, it is simultaneously extracted at a rate of 20 mL / min and sent to the cathode zone to form a circulation system.

[0059] like Figure 2 As shown, in this embodiment, the raw flue gas containing CO2 is processed... Figure 1 The battery device shown captures CO2 and generates electricity, then emits the remaining waste gas. The potassium bicarbonate produced during the capture and power generation process is heated to obtain CO2 and K2CO3, thus achieving regeneration. CO2 and K2CO3 are then used as reactants in the cathode and anode regions of the battery device, respectively.

[0060] A power load is connected between the cathode and anode, and the output power is adjusted by controlling the resistance of the power load. At 25°C, the current is set to increase from 0mA to the maximum output current at a rate of 2mA / s. Under these conditions, the maximum battery voltage is measured to be 0.58V, and the maximum power density is 45W / m³. 2 The CO2 conversion rate is 21%.

[0061] Comparative Example 1

[0062] The operation method of this comparative example is the same as that of the embodiment, except that K2CO3 is replaced with Na2SO4.

[0063] At a temperature of 25℃, with the current increased from 0mA to the maximum output current at a rate of 2mA / s, the measured maximum battery voltage was 0.52V, and the maximum power density was 35W / m³. 2 The CO2 conversion rate is 17%.

[0064] The above description is merely a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, based on the technical teachings provided by the present invention and as common knowledge in the field, other equivalent modifications and improvements can be made, and these should also be considered within the scope of protection of the present invention.

Claims

1. A method for capturing carbon dioxide, the method comprising: Step A, mixing a potassium carbonate solution and carbon dioxide gas to obtain a suspension, the suspension being filtered to obtain a filtrate; Step B, after the battery device is powered on, the filtrate is introduced into a cathode region of the battery device, and carbon dioxide gas is introduced into the cathode region; Step C, after the solution in the cathode region is heated and the carbon dioxide is separated, the solution is introduced into an anode region of the battery device; In step A, the concentration of the potassium carbonate solution is 0.5-10 mol / L, and the carbon dioxide gas is introduced into the potassium carbonate solution at a rate of 0.01-2 L / min to obtain the suspension.

2. The carbon dioxide capture method of claim 1, wherein, The cathode electrode of the battery device is selected from a carbon cloth electrode, and the anode electrode is selected from a porous membrane gas diffusion electrode.

3. The carbon dioxide capture method of claim 2, wherein, The cathode electrode is a carbon cloth supported electrode, and the supported element is selected from at least one of platinum, palladium and nickel; and the anode electrode is a hydrogen gas diffusion electrode.

4. The carbon dioxide capture method according to any one of claims 1 to 3, wherein, The battery device is provided with a cation exchange membrane to separate the battery device into the anode region and the cathode region.

5. The carbon dioxide capture method according to any one of claims 1 to 3, wherein, In step A, the suspension is stirred before the filtration.

6. The carbon dioxide capture method of claim 5, wherein, The stirring conditions include a stirring speed of 50-1000 rpm and a stirring time of 1-60 min.

7. The carbon dioxide capture method according to any one of claims 1 to 3, wherein, In step B, the rate of introducing the carbon dioxide gas into the cathode region is 0.01-2 L / min.

8. The carbon dioxide capture method according to any one of claims 1 to 3, wherein, After step C, the solution in the anode region is introduced into the cathode region.

9. The carbon dioxide capture method according to any one of claims 1 to 3, wherein, In step C, the solution is extracted from the cathode region at a rate of 5-1000 mL / min for the heating treatment.

10. The carbon dioxide capture method according to any one of claims 1 to 3, wherein, In step A, the filtrate is circulated between a filtrate storage device and the cathode region at a rate of 5-1000 mL / min.

11. A carbon dioxide capture system for use in the method of any one of claims 1-10, characterized in that, The system comprises the battery device, the filtrate storage device and a circulation device, and the circulation device can circulate the filtrate between the filtrate storage device and the cathode region of the battery device.

12. Use of the method for capturing carbon dioxide according to any one of claims 1-10 or the system for capturing carbon dioxide according to claim 11 in capturing carbon dioxide.

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