Carbon dioxide capture method and system capable of simultaneously producing carbon monoxide and hydrogen gas.

Abstract

A method and system for collecting carbon dioxide capable of simultaneously producing carbon monoxide and hydrogen gas is provided. The method for collecting carbon dioxide capable of simultaneously producing carbon monoxide and hydrogen gas includes the steps of collecting carbon dioxide as a target component using an alkaline solution to obtain a carbonate-containing aqueous solution, performing a first electrolysis process on the carbonate-containing aqueous solution to obtain a bicarbonate-containing aqueous solution and hydrogen gas, and performing a second electrolysis process on the bicarbonate-containing aqueous solution in the presence of a catalyst to obtain carbon monoxide and hydrogen gas, the catalyst being one or more selected from the group consisting of metal elements, alloys, and compounds of Groups VIII, IB, IIB, IVA, and lanthanoid elements. The method allows the collected carbon dioxide to be consumed and used as a synthetic gas, further expanding the application field of carbon dioxide resource recovery, and also significantly reducing power consumption and process costs by converting a part of the carbonate in the carbonate solution into bicarbonate before the first electrolysis process.

Description

[Technical Field]

[0001] This application is based on and claims priority from a Chinese application with application number 202210311730.8 and filing date March 28, 2022, and the disclosures of said Chinese application are again incorporated into this application as a whole. This invention relates to the field of carbon dioxide capture, and more specifically to a carbon dioxide capture method and system capable of simultaneously producing carbon monoxide and hydrogen gas. [Background technology]

[0002] Currently, chemical absorption methods using liquid alkanolamines as CO2 absorbers have the advantages of rapid absorption and simple processes, making them one of the most studied and widely used techniques for CO2 capture. However, the regeneration process of alkanolamine absorbers requires the use of large amounts of vapor to absorb a certain amount of latent heat of vaporization, resulting in high energy consumption. Furthermore, the alkanolamine solvent decomposes to some extent during use, leading to amine loss and increased running costs.

[0003] To address the high energy consumption associated with using liquid alkanolamine solvents, CO2 capture using solid adsorbents / absorbents has become a focus of research. The regeneration process of such adsorbents / absorbents avoids the large amount of heat of vaporization required for water, and energy consumption is primarily due to the sensible heat of material temperature rise during regeneration and the heat of chemical reactions necessary for regeneration, significantly reducing regeneration energy consumption. However, this method places high demands on the solid adsorbent / absorbent; the adsorbent / absorbent used must possess excellent adsorption performance and thermal stability. High-performance adsorbents / absorbents are generally expensive, resulting in high initial investment costs. Furthermore, the development of suitable process equipment and process flows is necessary. Related adsorption and regeneration equipment typically utilizes fluidized beds, inevitably leading to material wear during operation and a certain amount of adsorbent / absorbent loss, increasing running costs. Therefore, relatively mature industrial applications of this method have not yet been reported.

[0004] Using inorganic alkaline solutions as absorbents for CO2 capture is less expensive than using solid adsorbents / absorbents. Furthermore, the carbonates obtained by absorbing CO2 with inorganic alkalis can usually be regenerated by reacting with Ca(OH)2. This method avoids the latent heat of vaporization of large amounts of water during the regeneration process, compared to chemical absorption methods using alkanolamine solvents. However, the Ca(OH)2 needed for regeneration is converted to CaCO3, which then needs to be calcined to become CaO, and then react with H2O again to regenerate Ca(OH)2. Therefore, this method is complex, and in addition, the calcination of CaCO3 increases energy consumption, and the consumption of calcination fuel leads to CO2 emissions, making it unfavorable in terms of both investment and running costs. Consequently, reducing the cost of CO2 capture is a major focus of current research. Furthermore, utilizing CO2 as a resource is another key point in current research. Products ultimately obtained by carbon capture technologies, which are mainstream in the market, are basically primarily CO2, and the utilization of the carbon element is singular. While it is possible to synthesize chemicals such as CO2-derived methanol and CO2-derived alkenes using captured CO2, the types of chemicals that need to be synthesized using CO2 as a raw material and the production capacity are limited. Therefore, how to further expand the application fields of CO2 as a resource, consume captured CO2 in a timely manner, and form a complete industrial chain is an important research direction.

[0005] In light of the above issues, there is a need to develop a CO2 capture method that can produce both CO and H2 simultaneously. [Overview of the project] [Problems that the invention aims to solve]

[0006] The main objective of the present invention is to provide a carbon dioxide collection method and system capable of simultaneously producing carbon monoxide and hydrogen gas, in order to solve the problems of conventional carbon dioxide collection methods, such as high collection costs and the fact that they produce only one product. [Means for solving the problem]

[0007] To achieve the above objective, one aspect of the present invention provides a carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas. The method comprises the steps of collecting carbon dioxide from a target component using an alkaline solution to obtain a carbonate-containing aqueous solution, and performing a first electrolysis process on the carbonate-containing aqueous solution. 1 The steps involve obtaining an aqueous solution containing bicarbonate and hydrogen gas, and in the presence of a catalyst 1 The process includes the step of performing a second electrolysis process on an aqueous solution containing bicarbonate to obtain carbon monoxide and hydrogen gas, wherein the catalyst is one or more selected from the group consisting of elemental metals, alloys, and compounds of Group VIII, Group IB, Group IIB, Group IVA, and lanthanide elements.

[0008] Furthermore, the product of the first electrolysis process further contains first crude oxygen gas, and first crude oxygen gas contains some carbon dioxide, and a carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas purifies the first crude oxygen gas using a partially carbonate-containing aqueous solution to produce pure oxygen gas and 2nd The steps include obtaining an aqueous solution containing bicarbonate, 2nd The first electrolysis process is performed on the bicarbonate-containing aqueous solution. 1 The process further includes the step of obtaining an aqueous solution containing bicarbonate.

[0009] Furthermore, during the first electrolysis process, the electrolytic cell voltage was 1.1-4V, and the current density was 500-8000 A / m³. 2 The pH of the carbonate-containing aqueous solution is 10-14, and the concentration of carbonate in the carbonate-containing aqueous solution is 1-4.5 mol / L.

[0010] Furthermore, the carbon dioxide collection method, in which the product of the first electrolysis process further includes a regenerated alkaline solution and which can simultaneously produce carbon monoxide and hydrogen gas, further includes the step of involving at least a portion of the regenerated alkaline solution and / or at least the cathode solution obtained in the second electrolysis process as an alkaline solution in the collection process.

[0011] Furthermore, at least some of the regenerated alkaline solutions are cooled before participating in the collection process.

[0012] Furthermore, in the second electrolysis process, the electrolytic cell voltage is 100 - 220 V, the current density is 500 - 10000 A / m 2 and the catalyst loading is 1 - 200 mg / cm 2 and 1 the pH of the aqueous solution containing bicarbonate is 8 - 13, 1 and the concentration of bicarbonate in the aqueous solution containing bicarbonate is 1.5 - 3.8 mol / L.

[0013] Furthermore, the operating temperature of the first electrolysis process is 70 - 95°C, and the operating temperature of the second electrolysis process is 20 - 90°C.

[0014] Furthermore, the catalyst is one or more selected from the group consisting of metallic Au, metallic Ni, metallic Zn, CuPb, CeO2, and ZnO, and the catalyst loading is 30 - 80 mg / cm 2 and

[0015] Furthermore, the product of the second electrolysis process further contains second crude oxygen gas. The second crude oxygen gas contains some carbon dioxide. A carbon dioxide capture method capable of co-producing carbon monoxide and hydrogen gas further includes a step of purifying the second crude oxygen gas using some carbonate-containing aqueous solution to obtain pure oxygen gas and 2nd an aqueous solution containing bicarbonate.

[0016] Furthermore, in the capture process, the pressure is normal pressure, the concentration of the carbonate-containing aqueous solution is 1 - 4.5 mol / L, and the pH is 10 - 13.

[0017] Furthermore, in the purification process, 2nd in the aqueous solution containing hydrogen carbonate, the ratio of the molar amount of hydrogen carbonate to the total molar amount of carbonate and hydrogen carbonate is (0.1 - 1):1.

[0018] [[ID=4i]]Furthermore, a carbon dioxide capture method capable of co-producing carbon monoxide and hydrogen gas further includes a step of allowing some carbonate-containing aqueous solution to re-participate in the capture process.

[0019] Furthermore, the molar ratio of carbon monoxide to hydrogen gas obtained in the second electrolysis process is (0.1 to 1):1.

[0020] Another aspect of the present invention further provides a carbon dioxide capture system capable of co-producing carbon monoxide and hydrogen gas. The carbon dioxide capture system capable of co-producing carbon monoxide and hydrogen gas includes a carbon dioxide capture device, a first electrolysis device, and a second electrolysis device. The carbon dioxide capture device is provided with an alkaline solution inlet, a target component inlet, and a carbonate-containing aqueous solution discharge outlet. The first electrolysis device is provided with a carbonate-containing aqueous solution inlet, 1 a bicarbonate-containing aqueous solution discharge outlet, and a hydrogen gas outlet. The carbonate-containing aqueous solution discharge outlet is communicated with the carbonate-containing aqueous solution inlet. The 1 inside of the second electrolysis device is provided with a catalyst, and the first electrolysis device is provided with a bicarbonate-containing aqueous solution inlet and a cathode gas outlet. The cathode gas outlet is used to discharge carbon monoxide and hydrogen gas. The catalyst is one or more selected from the group consisting of simple metals, alloys, and compounds of Group VIII, Group IB, Group IIB, Group IVA, and lanthanoid elements.

[0021] Furthermore, the first electrolysis device is further provided with a first crude oxygen discharge outlet. The carbon dioxide capture system capable of co-producing carbon monoxide and hydrogen gas oxygen further includes a purification device. oxygen The purification device is provided with a crude oxygen inlet, an alkaline absorbent inlet, and 2nd a bicarbonate-containing aqueous solution discharge outlet. The crude oxygen inlet is communicated with the first crude oxygen discharge outlet. 2nd The bicarbonate-containing aqueous solution discharge outlet is carbonate communicated with the containing aqueous solution inlet.

[0022] Furthermore, the carbonate-containing aqueous solution discharge outlet is communicated with the alkaline absorbent inlet and the alkaline solution inlet respectively.

[0023] Furthermore, the first electrolysis device further includes a regenerated alkaline liquid discharge outlet, and the regenerated alkaline liquid discharge outlet and the alkaline solution inlet are communicated via a regenerated alkaline liquid transport pipeline.

[0024] Furthermore, the carbon dioxide capture system, which is capable of producing both carbon monoxide and hydrogen gas, is further equipped with a buffer and a cooling device, and these buffers and cooling devices are sequentially installed in the regenerated alkaline liquid transport pipeline along the flow direction of the regenerated alkaline liquid.

[0025] Furthermore, the second electrolytic device is further equipped with a cathode electrolyte outlet and a second crude oxygen outlet. The cathode electrolyte outlet is connected to the alkaline solution inlet, and the second crude oxygen outlet is connected to the crude oxygen inlet. [Effects of the Invention]

[0026] By applying the technical solutions of the present invention, the objective of reducing carbon dioxide emissions can be achieved by capturing carbon dioxide from a target component (e.g., air or combustion exhaust gas) and converting it into a carbonate-containing aqueous solution. In the first electrolysis process, the carbonate-containing aqueous solution is lightly electrolyzed to convert the carbonate to bicarbonate, thereby regenerating the alkaline absorption solution and also producing some hydrogen gas as a by-product. Due to the action of a catalyst, a catalytic electrolytic reaction occurs in the second electrolysis process, yielding carbon monoxide and hydrogen gas. With the above method, the captured carbon dioxide can be consumed and utilized as synthesis gas, further expanding the application fields of carbon dioxide resource utilization. At the same time, by converting some of the carbonate in the carbonate solution to bicarbonate before the first electrolysis process, power consumption and process costs are significantly reduced. [Brief explanation of the drawing]

[0027] The drawings comprising this application are provided to provide a further understanding of the present invention, and the exemplary embodiments and descriptions thereof are for interpretation purposes only and do not unduly limit the present invention. [Figure 1] This is a schematic diagram of the structure of a carbon dioxide collection system capable of simultaneously producing carbon monoxide and hydrogen gas, as described in this application. [Modes for carrying out the invention]

[0028] In addition, the embodiments and features described herein can be combined with each other, as long as they do not contradict each other. The present invention will now be described in detail in relation to the embodiments.

[0029] As explained in the background technology section, conventional carbon dioxide collection methods have drawbacks such as high collection costs and the production of a single product. To solve these problems, this application provides a carbon dioxide collection method capable of producing both carbon monoxide and hydrogen gas. The carbon dioxide collection method capable of producing both carbon monoxide and hydrogen gas comprises the steps of collecting carbon dioxide from a target component using an alkaline solution to obtain a carbonate-containing aqueous solution, and then performing a first electrolysis process on the carbonate-containing aqueous solution. 1 The steps involve obtaining an aqueous solution containing bicarbonate and hydrogen gas, and in the presence of a catalyst 1 The process includes the step of performing a second electrolysis process on an aqueous solution containing bicarbonate to obtain carbon monoxide and hydrogen gas, wherein the catalyst is one or more selected from the group consisting of elemental metals, alloys, and compounds of Group VIII, Group IB, Group IIB, Group IVA, and lanthanide elements.

[0030] The above method allows for the collection of carbon dioxide from target components (e.g., air or combustion exhaust gas) and its conversion into a carbonate-containing aqueous solution, thereby achieving the objective of reducing carbon dioxide emissions. In the first electrolysis process, the carbonate-containing aqueous solution is lightly electrolyzed, converting the carbonate to bicarbonate, regenerating the alkaline absorption solution, and also producing some hydrogen gas as a by-product. Due to the action of a catalyst, the bicarbonate undergoes a catalytic electrolytic reaction in the second electrolysis process, yielding carbon monoxide and hydrogen gas. The above method allows for the consumption and utilization of the collected carbon dioxide as synthesis gas, further expanding the application fields of carbon dioxide resource utilization. At the same time, by converting some of the carbonate in the carbonate solution to bicarbonate before the first electrolysis, power consumption and process costs are significantly reduced.

[0031] In preferred embodiments, the product of the first electrolysis process further contains a first crude oxygen gas, the first crude oxygen gas contains some carbon dioxide, and a carbon dioxide collection method capable of producing both carbon monoxide and hydrogen gas involves purifying the first crude oxygen gas using a partially carbonate-containing aqueous solution to produce pure oxygen gas and 2nd The steps include obtaining an aqueous solution containing bicarbonate, 2nd The first electrolysis process is performed on the bicarbonate-containing aqueous solution. 1 The process further includes the step of obtaining an aqueous solution containing bicarbonate.

[0032] By purifying the first crude oxygen gas using the carbonate-containing aqueous solution obtained during the carbon dioxide capture process, the carbon dioxide carried out by the oxygen gas can be recovered, which is advantageous in improving the carbon dioxide capture efficiency during the capture process. Furthermore, some of the carbonates in the carbonate-containing aqueous solution can be converted to bicarbonates during the purification process, and by using these as the electrolyte in the first electrolysis process, the power consumption of the first electrolysis process can be reduced to some extent, ultimately reducing the energy consumption of the system and lowering the overall process cost.

[0033] The first electrolysis process can convert the carbonate-containing aqueous solution into a bicarbonate-containing aqueous solution. In a preferred embodiment, during the first electrolysis process, the electrolytic cell voltage is 1.1 to 4V, and the current density is 500 to 8000 A / m². 2 The pH of the carbonate-containing aqueous solution is 10 to 14, and the concentration of carbonate in the carbonate-containing aqueous solution is 1 to 4.5 mol / L. The electrolytic cell voltage, current density, pH of the carbonate-containing aqueous solution, and concentration of carbonate in the first electrolysis process are within the above range but are not limited thereto; however, limiting them to the above range is advantageous for further improving the conversion rate of bicarbonate.

[0034] In preferred embodiments, the product of the first electrolysis process further includes a regenerated alkaline solution, and the carbon dioxide capture method capable of co-producing carbon monoxide and hydrogen gas further includes the step of involving at least a portion of the regenerated alkaline solution and / or at least the cathode solution obtained in the second electrolysis process as an alkaline solution in the capture process. Regenerating a portion of the alkaline solution (regenerated alkaline solution) in the first electrolysis process and using it again as a capture agent in the carbon dioxide capture process is advantageous in improving the raw material utilization rate in the overall process and therefore advantageous in further reducing costs.

[0035] Typically, after the first electrolysis process, the regenerated alkaline solution has a certain temperature. To suppress the influence of carbon dioxide absorption during the reuse process of the regenerated alkaline solution, it is preferable to first perform a cooling treatment on at least a portion of the regenerated alkaline solution before involving it in the collection process.

[0036] In a preferred embodiment, during the second electrolysis process, the electrolytic cell voltage is 100-220V and the current density is 500-10000A / m³. 2 The amount of catalyst supported is 1-200 mg / cm³. 2 And, 1 The pH of an aqueous solution containing bicarbonate is 8-13. 1 The concentration of bicarbonate in the bicarbonate-containing aqueous solution is 1.5 to 3.8 mol / L. The electrolytic cell voltage, current density, catalyst load, pH of the bicarbonate-containing aqueous solution, and bicarbonate concentration in the second electrolysis process are within but not limited to the above ranges; however, limiting them to the above ranges is advantageous for further improving the carbon monoxide yield.

[0037] Preferably, the operating temperature for the first electrolysis process is 70 to 95°C, and the operating temperature for the second electrolysis process is 20 to 90°C. Since temperature affects the efficiency of the electrolysis process to some extent, limiting the operating temperatures of the first and second electrolysis processes to the above ranges is advantageous for further improving the carbon monoxide yield.

[0038] To further improve the carbon monoxide yield and reaction activity, preferably, the catalyst used in this application includes, but is not limited to, one or more selected from the group consisting of metallic Au, metallic Ni, metallic Zn, CuPb, CeO2, and ZnO, and the catalyst loading amount is 30 to 80 mg / cm³. 2 That is the case.

[0039] In the second electrolysis process, a certain amount of crude oxygen gas (second crude oxygen gas) is also generated, and this second crude oxygen gas contains some carbon dioxide. In order to recover the carbon dioxide in the above second crude oxygen gas and improve the utilization rate of carbon elements, preferably, the above carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas involves purifying the second crude oxygen gas using a partially carbonate-containing aqueous solution, and then producing pure oxygen gas and 2nd The process further includes the step of obtaining an aqueous solution containing bicarbonate.

[0040] In preferred embodiments, during the collection process, the pressure is atmospheric pressure, the concentration of the carbonate-containing aqueous solution is 1 to 4.5 mol / L, and the pH is 10 to 13.

[0041] In preferred embodiments, during the purification process, the ratio of the molar amount of bicarbonate to the total molar amount of carbonate is (0.1~1):1. The ratio of the molar amount of bicarbonate to the total molar amount of carbonate is included in but not limited to the above range, and limiting it to the above range is advantageous for improving the CO yield in the second electrolysis process. Since the first electrolysis process also generates some hydrogen gas, mixing this with the carbon monoxide and hydrogen gas generated in the second electrolysis process allows for flexible adjustment of the carbon monoxide and hydrogen ratio in the synthesis gas.

[0042] Preferably, the molar ratio of carbon monoxide to hydrogen obtained in the second electrolysis process is (0.1 to 1):1.

[0043] A second aspect of this application further provides a carbon dioxide collection system capable of co-producing carbon monoxide and hydrogen gas. The carbon dioxide collection system capable of co-producing carbon monoxide and hydrogen gas includes a carbon dioxide collection device 10, a first electrolytic device 20, and a second electrolytic device 30. The carbon dioxide collection device 10 is equipped with an alkaline solution inlet 101, a target component inlet 102, and a carbonate-containing aqueous solution outlet 103. 1st electrolyzer 20 In the carbonate-containing aqueous solution inlet 201, 1 A bicarbonate-containing aqueous solution outlet 202 and a hydrogen gas outlet 203 are installed, and the carbonate-containing aqueous solution outlet 103 is connected to the carbonate-containing aqueous solution inlet 201. A catalyst is installed inside the second electrolytic device 30, and 2nd electrolyzer 30 for 1 An inlet for a bicarbonate-containing aqueous solution and a cathode gas outlet are provided, and the cathode gas outlet is used to discharge carbon monoxide and hydrogen. The catalyst is one or more selected from the group consisting of elemental metals, alloys, and compounds of Group VIII, Group IB, Group IIB, Group IVA, and lanthanides.

[0044] The carbon dioxide capture device 10 captures carbon dioxide from target components such as air or combustion exhaust gas and converts it into a carbonate-containing aqueous solution, thereby reducing carbon dioxide emissions. The first electrolytic device 20 mildly electrolyzes the carbonate-containing aqueous solution to convert the carbonates into bicarbonates, thereby regenerating the alkaline absorption solution and producing some hydrogen gas as a by-product. Due to the action of a catalyst, the bicarbonates undergo a catalytic electrolytic reaction in the second electrolytic device 30, yielding carbon monoxide and hydrogen gas. With the above capture system, the captured carbon dioxide can be consumed and utilized as synthesis gas, further expanding the application fields of carbon dioxide resource utilization. At the same time, by converting some of the carbonates in the carbonate solution into bicarbonates before the first electrolysis, power consumption and process costs are significantly reduced.

[0045] In a preferred embodiment, the first electrolytic device 20 is further equipped with a first crude oxygen outlet, and the carbon dioxide collection system capable of producing carbon monoxide and hydrogen gas together further includes an oxygen purifier 40, the oxygen purifier 40 having a crude oxygen inlet 401, an alkaline absorbent inlet 402 and 2nd A bicarbonate-containing aqueous solution outlet 403 is installed, and the crude oxygen inlet 401 is connected to the first crude oxygen outlet. 2nd The outlet 403 for the bicarbonate-containing aqueous solution is Inlet 201 for carbonate-containing aqueous solution It is connected to the oxygen purification device 40. In the oxygen purification device 40, by purifying the first crude oxygen gas using the carbonate-containing aqueous solution obtained in the carbon dioxide collection device 10, carbon dioxide carried out by the oxygen gas can be recovered, which is advantageous in improving the carbon dioxide collection efficiency in the collection process. In addition, in the purification process, some of the carbonate in the carbonate-containing aqueous solution can be converted to bicarbonate, and by using this as the electrolyte in the first electrolytic device 20, the power consumption of the first electrolytic device 20 can be reduced to some extent, ultimately reducing the energy consumption of the system and lowering the overall process cost.

[0046] In order to further improve the utilization rate of raw materials and reduce process costs, preferably, the carbonate-containing aqueous solution outlet 103 is connected to the alkaline absorbent inlet 402 and the alkaline solution inlet 101, respectively.

[0047] In order to further improve the utilization rate of raw materials and reduce process costs, in a preferred embodiment, the first electrolytic device 20 is further equipped with a regenerated alkaline solution outlet 204, and the regenerated alkaline solution outlet 204 and the alkaline solution inlet 101 are in communication via a regenerated alkaline solution transport pipeline.

[0048] Preferably, a carbon dioxide capture system capable of simultaneously producing carbon monoxide and hydrogen gas further comprises a buffer device 50 and a cooling device 60, and the buffer device 50 and the cooling device 60 are sequentially installed in the regenerated alkaline liquid transport pipeline along the flow direction of the regenerated alkaline liquid. In the buffer device 50, the concentration and pH of the regenerated alkaline liquid can be adjusted by separately adding water. Since the regenerated alkaline liquid discharged after the first electrolysis usually has a certain temperature, installing the cooling device 60 is advantageous in suppressing the influence of carbon dioxide absorption during the reuse process of the regenerated alkaline liquid.

[0049] The second electrolytic device 30 also discharges a certain amount of crude oxygen gas (second crude oxygen gas), which contains some carbon dioxide. In order to recover the carbon dioxide in the second crude oxygen gas and improve the utilization rate of carbon elements, preferably the second electrolytic device 30 is further equipped with a cathode electrolyte outlet and a second crude oxygen outlet, the cathode electrolyte outlet and the alkaline solution inlet 101 are in communication, and the second crude oxygen outlet and the crude oxygen inlet 401 are in communication.

[0050] The present application will be described in more detail below with reference to specific embodiments, but these embodiments should not be understood as limitations on the scope of protection claimed by this application.

[0051] [Example 1] A carbon dioxide capture method capable of simultaneously producing carbon monoxide and hydrogen gas includes the following steps.

[0052] In the carbon dioxide capture device 10, the carbon dioxide capture process includes that an alkaline solution enters the carbon dioxide capture device 10 from the alkaline solution inlet 101, and after the target component enters the carbon dioxide capture device 10 from the target component inlet, the alkaline solution captures carbon dioxide in the target component to obtain an aqueous solution containing carbonate. Here, the target component is air, the volume fraction of carbon dioxide is 400 ppm, the alkaline solution is a 1.1 mol / L KOH aqueous solution, and the aqueous solution containing carbonate is a 2.1 mol / L K2CO3 solution with a pH of 13.6. The aqueous solution containing carbonate is discharged from the aqueous solution containing carbonate discharge port 103, and the gas not captured is discharged from the top gas discharge port 104.

[0053] The aqueous solution containing carbonate is controlled by the aqueous solution containing carbonate transport pump 11 and the flow control valve 12 and enters the first electrolyzer 20 from the aqueous solution containing carbonate inlet 201. The first electrolysis process includes the following. Put the above K2CO3 solution into the electrolytic cell, and control the electrolytic cell voltage to 2.6 V and the current density to 1560 A / m 2 At the cathode, a KOH solution (regenerated alkaline solution) and hydrogen gas are obtained. The hydrogen gas is discharged from the hydrogen gas outlet 203, and the obtained KOH solution is discharged from the regenerated alkaline solution discharge port 204. The KOH solution is transported to the buffer device 50 by the regenerated alkaline solution transport pump 22, water is introduced into the buffer device 50 through the external makeup water transport pipeline 51 to adjust its pH, and then it is cooled by the cooling device 60 and then returned to the carbon dioxide capture device 10 through the alkaline solution inlet 101 for reuse. At the anode, a KHCO3 solution ( 1 an aqueous solution containing bicarbonate), and a first crude oxygen gas containing 42% CO2 by volume on a dry basis are obtained. The above 1 aqueous solution containing bicarbonate is 1 discharged from the 202 aqueous solution containing bicarbonate discharge port, The anolyte is transported to the second electrolytic device 30 by the first electrolytic device anolyte transport pump 21. and the first crude oxygen gas is discharged from the first crude oxygen gas discharge port.

[0054] The The second electrolysis process includes the following. The KHCO3 solution obtained at the anode in the first electrolysis process is transported to the electrolytic cell, the electrolytic cell voltage is set to 150 V, and the current density is 2500 A / m2 The electrolysis temperature was set to 45°C, and the catalyst load on the electrolytic cell ion membrane was 36 mg / cm³. 2 The catalyst used is metallic Au. At the cathode, a synthesis gas with a molar ratio of CO to H2 of 0.49:1 and a cathode electrolyte are obtained. At the anode, a second crude oxygen gas containing 9% CO2 by dry weight is obtained. The second crude oxygen gas is discharged from the second crude oxygen gas outlet, and the cathode electrolyte is returned to the carbon dioxide collection device 10 from the alkaline solution inlet by the second electrolytic device cathode liquid transport pump 31.

[0055] The first and second crude oxygen gases are transported by the anode gas transport fan 23 and enter the oxygen purification unit 40 from the crude oxygen inlet 401. The alkaline absorbent (at least a portion of the carbonate-containing aqueous solution obtained in the carbon dioxide capture process) enters the oxygen purification unit 40 from the alkaline absorbent inlet 402. The purification process includes the following: Before performing the first electrolysis on the portion of the carbonate-containing aqueous solution obtained in the carbon dioxide capture process, the first and second crude oxygen gases are first purified using this portion of the solution. 2nd A bicarbonate-containing aqueous solution and purified oxygen gas are obtained. Here, 2nd In the bicarbonate-containing aqueous solution, the ratio of the molar amount of bicarbonate to the total molar amount of carbonate and bicarbonate is 0.23:1. 2nd The bicarbonate-containing aqueous solution is discharged from outlet 403 and subsequently transported by the purification column bottom liquid transport pump 41. 2nd electrolyzer 30 The material is placed in the electrolytic cell and the electrolysis operation is performed. Oxygen gas is discharged from the top exhaust port 404 of the tower.

[0056] In this embodiment, it can be seen that the CO2 capture rate is 51% under the above conditions. Compared to directly performing the first electrolysis process on the carbonate solution, by installing a purification process, the recovery rate of captured CO2 can be improved from the conventional ~70% to ~98.6%, and the purification process converts some of the K2CO3 in the carbonate solution obtained in the carbon dioxide capture process to KHCO3, reducing the energy consumption of the first electrolysis process to ~13.6%. The single-pass conversion rate of carbon dioxide in the second electrolysis process is 28.7%, and the H2 obtained in the first electrolysis process can be doped with the synthesis gas obtained in the second electrolysis process according to downstream demand, so that the carbon-hydrogen ratio of the final synthesis gas can be adjusted within a predetermined range, enabling flexible adjustment.

[0057] [Example 2] This differs from Example 1 in that the catalyst is metallic Zn.

[0058] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 15.3%.

[0059] [Example 3] This differs from Example 1 in that the catalyst is metallic nickel.

[0060] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 16.1%.

[0061] [Example 4] This differs from Example 1 in that the catalyst is CuPb.

[0062] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 24.6%.

[0063] [Example 5] This differs from Example 1 in that the catalyst is CeO2.

[0064] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 22.3%.

[0065] [Example 6] This method differs from Example 1 in that the catalyst is ZnO.

[0066] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 19.4%.

[0067] [Example 7] Compared to Example 1, the catalyst loading amount is 30 mg / cm³. 2 They differ in that respect.

[0068] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 24.6%.

[0069] [Example 8] Compared to Example 1, the catalyst loading amount is 80 mg / cm³. 2 They differ in that respect.

[0070] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 29.8%.

[0071] [Example 9] Compared to Example 1, the catalyst loading amount is 16 mg / cm³. 2 They differ in that respect.

[0072] In the second electrolysis process, the single-pass conversion rate of carbon dioxide was 20.4%.

[0073] From the above explanation, it can be seen that the above embodiments of the present invention can achieve the following technical effects.

[0074] (1) In the CO2 collection and utilization system and method according to the present invention that can produce both CO and H2, crude O2 is purified using a carbonate-containing aqueous solution from a CO2 absorption tower, and the CO2 that has been removed by the O2 is recovered to ensure the collection efficiency of the system. Furthermore, by converting some of the carbonates in the carbonate-containing aqueous solution into bicarbonates and then electrolyzing them in an electrolytic cell, the power consumption of the electrolytic cell is reduced to some extent, and ultimately the energy consumption of the system is reduced.

[0075] (2) In the CO2 collection and utilization system and method according to the present invention that can produce both CO and H2, the collected CO2 is reacted with water by secondary catalytic electrolysis to ultimately convert it into synthesis gas of CO and H2, thereby allowing the collected CO2 to be consumed and utilized as synthesis gas, further expanding the application fields of CO2 resource utilization.

[0076] (3) In the CO2 collection and utilization system and method according to the present invention that can produce both CO and H2, the alkaline absorption solution can be regenerated by primary electrolysis, and some pure H2 can be produced as a by-product. The obtained H2 may be sold directly as a product, or it may be doped with the synthesis gas of CO and H2 obtained in the secondary electrolytic cell according to downstream demand to achieve flexible adjustment of the carbon-hydrogen ratio in the synthesis gas.

[0077] Furthermore, terms such as "first," "second," etc., used in the specification and claims of this application are not intended to describe a specific order or sequence, but rather to distinguish similar subjects. These terms may be replaced as appropriate so that the embodiments of this application described herein may be implemented, for example, in an order other than those described herein.

[0078] The foregoing describes only preferred embodiments of the present invention and does not limit it; those skilled in the art will know that the present invention can be modified and altered in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should all be within the scope of protection of the present invention. [Explanation of Symbols]

[0079] 10. Carbon dioxide capture device 101 Alkaline solution inlet 102 Target ingredient entry point 103 Carbonate-containing aqueous solution outlet 104 Tower top gas outlet 11. Carbonate-containing aqueous solution transport pump 12 Flow control valve 20 1st electrolysis device 201 Inlet for carbonate-containing aqueous solution 202 1 Discharge port for aqueous solution containing bicarbonate 203 Hydrogen gas outlet 204 Recycled alkaline solution outlet 21. First electrolytic device anode liquid transport pump 22 Regenerated Alkaline Liquid Transport Pump 23 Anode gas transport fan 30 2nd electrolyzer 31. Second electrolytic device cathode liquid transport pump 40. Oxygen gas purification system 401 Crude oxygen inlet 402 Alkaline absorbent inlet 403 2nd Discharge port for aqueous solution containing bicarbonate 404 Tower top exhaust vent 41 Purification column bottom liquid transport pump 50 Shock absorber 51 External supplementary water transport pipe 60 Cooling device

Claims

1. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas, The process involves using an alkaline solution to capture carbon dioxide from the target component and obtaining an aqueous solution containing carbonate, The first step is to perform an electrolysis process on the carbonate-containing aqueous solution to obtain a first crude oxygen gas containing some carbon dioxide, a first bicarbonate-containing aqueous solution, and hydrogen gas. The steps include: performing a second electrolysis process on the first bicarbonate-containing aqueous solution in the presence of a catalyst to obtain a second crude oxygen gas containing some carbon dioxide, carbon monoxide, and hydrogen gas; The steps include: purifying the first crude oxygen gas using a portion of the carbonate-containing aqueous solution to obtain pure oxygen gas and a second bicarbonate-containing aqueous solution; The steps include: purifying the second crude oxygen gas using a portion of the carbonate-containing aqueous solution to obtain pure oxygen gas and a second bicarbonate-containing aqueous solution; The process includes the step of performing the first electrolysis step on the second bicarbonate-containing aqueous solution to obtain the first bicarbonate-containing aqueous solution, The catalyst is metal Au, metal Ni, metal Zn, CuPb, CeO ２ , and one or more species selected from the group consisting of ZnO, A carbon dioxide collection method characterized by the ability to simultaneously produce carbon monoxide and hydrogen gas.

2. In the first electrolysis process, the electrolytic cell voltage was 1.1 to 4 V, and the current density was 500 to 8000 A / m². ２ The pH of the carbonate-containing aqueous solution is 10 to 14, and the concentration of carbonate in the carbonate-containing aqueous solution is 1 to 4.5 mol / L. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

3. The product of the first electrolysis process further contains a regenerated alkaline solution. The carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas is, The process further includes a step of introducing at least a portion of the regenerated alkaline solution and / or at least the cathode solution obtained in the second electrolysis process as the alkaline solution to participate in the collection process. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

4. At least some of the regenerated alkaline solution is cooled before participating in the collection process. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas, as described in feature 3.

5. In the second electrolysis process described above, the electrolytic cell voltage is 100 to 220 V, and the current density is 500 to 10000 A / m². ２ The amount of catalyst supported is 1 to 200 mg / cm³. ２ The pH of the first bicarbonate-containing aqueous solution is 8 to 13, and the concentration of bicarbonate in the first bicarbonate-containing aqueous solution is 1.5 to 3.8 mol / L. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

6. The operating temperature for the first electrolysis process is 70 to 95°C, and the operating temperature for the second electrolysis process is 20 to 90°C. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

7. The amount of catalyst supported is 30-80 mg / cm³. ２ That is, A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

8. During the collection process, the pressure is normal, the carbonate-containing aqueous solution has a concentration of 1 to 4.5 mol / L, and a pH of 10 to 13. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

9. In the purification process described above, in the aqueous solution containing the second bicarbonate, the ratio of the molar amount of bicarbonate to the total molar amount of carbonate and bicarbonate is (0.1 to 1):

1. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

10. The carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas is, The further step includes reintroducing a portion of the carbonate-containing aqueous solution into the collection process. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

11. The molar ratio of carbon monoxide to hydrogen gas obtained in the second electrolysis process is (0.1 to 1):

1. A carbon dioxide collection method capable of simultaneously producing carbon monoxide and hydrogen gas as described in feature 1.

12. A carbon dioxide collection system capable of simultaneously producing carbon monoxide and hydrogen gas, It includes a carbon dioxide collection device (10), a first electrolysis device (20), a second electrolysis device (30), and an oxygen gas purification device (40), The carbon dioxide collection device (10) is provided with an alkaline solution inlet (101), a target component inlet (102), and a carbonate-containing aqueous solution outlet (103). The first electrolytic device (20) is provided with a carbonate-containing aqueous solution inlet (201), a first bicarbonate-containing aqueous solution outlet (202), a hydrogen gas outlet (203), a first crude oxygen outlet, and a regenerated alkaline solution outlet (204), the carbonate-containing aqueous solution outlet (103) and the carbonate-containing aqueous solution inlet (201) are in communication, and the regenerated alkaline solution outlet (204) and the alkaline solution inlet (101) are in communication via a regenerated alkaline solution transport pipeline. A catalyst is installed inside the second electrolytic device (30), and the second electrolytic device (30) is provided with a first bicarbonate-containing aqueous solution inlet, a cathode gas outlet, a cathode electrolyte outlet, and a second crude oxygen outlet, the cathode gas outlet is used to discharge carbon monoxide and hydrogen gas, and the cathode electrolyte outlet and the alkaline solution inlet (101) are in communication. The catalyst is metal Au, metal Ni, metal Zn, CuPb, CeO ２ , and one or more selected from the group consisting of ZnO, The oxygen gas purification apparatus (40) is equipped with a crude oxygen inlet (401), an alkaline absorbent inlet (402), and a second bicarbonate-containing aqueous solution outlet (403). The crude oxygen inlet (401) and the first crude oxygen outlet are connected, the second crude oxygen outlet and the crude oxygen inlet (401) are connected, and the second bicarbonate-containing aqueous solution outlet (403) and the carbonate-containing aqueous solution inlet (201) are connected. A carbon dioxide collection system capable of simultaneously producing carbon monoxide and hydrogen gas, characterized by the following features.

13. The carbonate-containing aqueous solution outlet (103) is connected to the alkaline absorbent inlet (402) and the alkaline solution inlet (101), respectively. A carbon dioxide collection system capable of simultaneously producing carbon monoxide and hydrogen gas, as described in claim 12.

14. The carbon dioxide collection system capable of simultaneously producing carbon monoxide and hydrogen gas further comprises a buffer (50) and a cooling device (60), and the buffer (50) and the cooling device (60) are sequentially installed in the transport pipeline of the regenerated alkaline liquid along the flow direction of the regenerated alkaline liquid. A carbon dioxide collection system capable of simultaneously producing carbon monoxide and hydrogen gas, as described in claim 12.

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