TWI819466B - System and method for carbon dioxide electrolysis - Google Patents

Abstract

A system and a method for carbon dioxide electrolysis are provided. The system for carbon dioxide electrolysis includes electrochemical electrolysis equipment and an absorption unit fluidly connected with the electrochemical electrolysis equipment. A cathode reactant and an anode reactant are electrolyzed by the electrochemical electrolysis equipment to form a cathode mixture and an anode mixture. The cathode reactant includes carbon dioxide or compounds that containing a bicarbonate group or a carbonate group. The cathode mixture includes carbon monoxide and hydrogen gas. The anode mixture includes chlorine gas. The cathode-mixture is processed by the absorption unit to separate out a syngas containing carbon monoxide and hydrogen gas.

Description

Carbon dioxide electrolysis system and method

The present invention relates to a carbon dioxide electrolysis system and method, in particular to a carbon dioxide electrolysis system and method that can produce synthetic gas and chlorine gas.

Carbon dioxide gas produced by burning petrochemical materials is the main cause of the greenhouse effect. In order to slow down the problem of global warming, how to convert carbon dioxide gas into other reusable energy sources is one of the current important research and development goals.

In the prior art, various technologies for reducing carbon dioxide are disclosed. One such technology is to combine photocatalysts with a water-splitting system to reduce carbon dioxide in a manner similar to a plant's photosynthetic system. It first uses photocatalysis to decompose water and generate hydrogen ions, and then uses the hydrogen ions to reduce carbon dioxide. However, this device is a batch reaction device and is not conducive to processing large amounts of carbon dioxide.

Another technology for reducing carbon dioxide is to dissolve carbon dioxide in the electrolyte and reduce carbon dioxide through electrocatalysis. However, the diffusion capacity and concentration of carbon dioxide are affected by time, which in turn affects the conversion rate of carbon dioxide. Moreover, the reduction products of carbon dioxide include a variety of hydrocarbons, such as methane, methanol, ethane, ethanol, acetic acid or ethylene. Not all products can be used as fuel or as basic raw materials for other chemicals, so there is still a need to After multiple separation and purification steps, it has the disadvantage of complicated steps.

Therefore, how to reduce carbon dioxide to slow down the greenhouse effect and make the carbon dioxide reduction products pure and reusable has become one of the important issues to be solved by this project.

The technical problem to be solved by the present invention is to provide a carbon dioxide electrolysis system and method in view of the shortcomings of the existing technology.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a carbon dioxide electrolysis system. The carbon dioxide electrolysis system includes an electrochemical electrolysis device and an absorption unit in fluid communication with the electrochemical electrolysis device. The electrochemical electrolysis device electrolyzes a cathode reactant and an anode reactant to form a cathode mixture and an anode mixture respectively. Wherein, the cathode reactant includes carbon dioxide or a compound containing bicarbonate or carbonate, the cathode mixture includes carbon monoxide and hydrogen, and the anode mixture includes chlorine. The absorption unit processes the cathode mixture and separates a synthesis gas including carbon monoxide and hydrogen.

In some embodiments, the absorption unit distinguishes the cathode mixture into a cathode gas product and a reflux liquid, the cathode gas product includes synthesis gas, the reflux liquid includes bicarbonate, carbonate or hydroxide, and the reflux liquid is returned to the electrochemical electrolysis equipment.

In some embodiments, the carbon dioxide electrolysis system further includes: a first reactant preparation unit, the first reactant preparation unit is fluidly connected between the electrochemical electrolysis equipment and the absorption unit, and the first reactant preparation unit receives the reflux liquid, and providing cathode reactants to electrochemical electrolysis equipment.

In some embodiments, the cathode mixture includes a cathode gas mixture and a cathode liquid mixture, and the absorption unit processes the cathode gas mixture.

In some embodiments, the cathode mixture includes a cathode liquid mixture, and the cathode liquid mixture includes metal ions, hydroxide ions, or metal hydroxides.

In some embodiments, the carbon dioxide electrolysis system further includes: a first gas-liquid separation unit, the first gas-liquid separation unit is fluidly connected between the electrochemical electrolysis equipment and the absorption unit, and the first gas-liquid separation unit connects the cathode to The mixture is divided into a cathode gas mixture and a cathode liquid mixture.

In some embodiments, the carbon dioxide electrolysis system further includes: a first liquid processing unit, the first liquid processing unit is in fluid communication with the electrochemical electrolysis device, the first liquid processing unit processes the cathode liquid mixture to produce a first treatment liquid, and the first treatment liquid returns to the electrochemical electrolysis equipment.

In some embodiments, the carbon dioxide electrolysis system further includes: a first reactant preparation unit, the first reactant preparation unit is fluidly connected between the electrochemical electrolysis equipment and the first liquid treatment unit, the first reactant preparation unit The unit receives the first treatment liquid and provides cathode reactants to the electrochemical electrolysis device.

In some embodiments, the anode mixture includes an anode gas mixture and an anode liquid mixture.

In some embodiments, the carbon dioxide electrolysis system further includes: a second gas-liquid separation unit, the second gas-liquid separation unit is fluidly connected to the electrochemical electrolysis device, and the second gas-liquid separation unit differentiates the anode mixture into anode gas. mixture with the anode liquid mixture.

In some embodiments, the carbon dioxide electrolysis system further includes: a second liquid processing unit, the second liquid processing unit is in fluid communication with the electrochemical electrolysis device, the second liquid processing unit processes the anode liquid mixture to produce a second process liquid, and the second treatment liquid returns to the electrochemical electrolysis equipment.

In some embodiments, the carbon dioxide electrolysis system further includes: a second reactant preparation unit, the second reactant preparation unit is fluidly connected between the electrochemical electrolysis equipment and the second liquid treatment unit, and the second reactant preparation unit receives The second treatment liquid provides anode reactants to the electrochemical electrolysis equipment.

In some embodiments, the electrochemical electrolysis device includes a plurality of electrolysis units; wherein each electrolysis unit includes a cathode electrode located in a cathode chamber, an anode electrode located in an anode chamber, and an electrode sandwiched between the cathode electrode and the anode. An ion exchange membrane between the electrodes.

In some embodiments, the cathode electrode is disposed in the cathode chamber, a cathode catalyst is formed on the cathode electrode, the anode electrode is disposed in the anode chamber, an anode catalyst is formed on the anode electrode, and each two adjacent electrolysis units are Insulating plate interval; wherein, the material of the cathode catalyst includes iron, cobalt, nickel, copper, ruthenium, rhodium, silver, iridium, platinum, gold, titanium or a carbon compound containing any of the above metals, and the material of the anode catalyst includes ruthenium , rhodium, iridium, titanium or metal halides, metal oxides or metal hydroxides containing any of the above metals.

In some embodiments, the cathode chamber has an inlet for receiving cathode reactants and an outlet for discharging the cathode mixture, and the anode chamber has an inlet for receiving anode reactants and an outlet for discharging the anode mixture.

In some embodiments, the cathode chamber has an inlet to receive cathode reactants and two outlets to discharge the cathode mixture, and the anode chamber has an inlet to receive anode reactants and two outlets to discharge the anode mixture.

In some embodiments, the cathode reactant further includes a catholyte, and the catholyte contains bicarbonate or carbonate; wherein, the anode reactant further includes an anolyte, and the anolyte contains chloride ions.

In some embodiments, the anolyte includes salts containing chloride ions.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide an electrolysis method of carbon dioxide. The electrolysis method of carbon dioxide includes: using an electrochemical electrolysis device to electrolyze a cathode reactant and an anode reactant to form a cathode mixture and an anode mixture respectively; and using an absorption unit to process the cathode mixture to separate carbon monoxide and hydrogen. of a synthetic gas. Wherein, the cathode reactant includes carbon dioxide or a compound containing carbonate or bicarbonate, the cathode mixture includes carbon monoxide and hydrogen, and the anode mixture includes chlorine.

In some embodiments, after the absorption unit processes the cathode mixture, the cathode mixture is divided into a cathode gas product and a reflux liquid, the cathode gas product includes synthesis gas, and the reflux liquid includes bicarbonate, carbonate or hydroxide; wherein , the electrolysis method of carbon dioxide further includes: returning the reflux liquid to the electrochemical electrolysis equipment.

In some embodiments, the carbon dioxide electrolysis method further includes: transporting the reflux liquid to a first reactant preparation unit, and the first reactant preparation unit provides cathode reactants to the electrochemical electrolysis device.

In some embodiments, the cathode mixture includes a cathode gas mixture and a cathode liquid mixture, and the cathode liquid mixture includes metal ions, hydroxide ions or metal hydroxides.

One of the beneficial effects of the present invention is that the carbon dioxide electrolysis system and method provided by the present invention can pass "the cathode reactant includes carbon dioxide or a compound containing carbonate or bicarbonate, and the cathode mixture includes carbon monoxide and Hydrogen, the anode mixture includes chlorine" and the technical solution of "the absorption unit processes the cathode mixture and separates a synthesis gas including carbon monoxide and hydrogen", and has a decomposable greenhouse gas (carbon dioxide), and also produces a product that can be used as Effect of fuel synthesis gases (carbon monoxide and hydrogen).

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and illustration and are not used to limit the present invention.

The following is a specific example to illustrate the implementation of the "carbon dioxide electrolysis system and method" disclosed in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depictions based on actual dimensions, as is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of the present invention. In addition, the term "or" used in this article shall include any one or combination of more of the associated listed items depending on the actual situation.

The invention provides a carbon dioxide electrolysis system, which includes an electrochemical electrolysis device and an absorption unit in fluid communication. Electrochemical electrolysis equipment is used to reduce carbon dioxide to achieve the effect of mitigating the greenhouse effect problem, and can also produce alkaline liquid products for commercial use. The absorption unit is used to separate carbon dioxide and carbon dioxide reduction products to obtain high-content synthesis gas (mixed gas of carbon monoxide and hydrogen), which can be used directly as fuel or as a basic raw material for other chemicals. In addition to synthesis gas, the gas phase products generated by the cathode may also include methane, ethane, ethylene or mixtures thereof, but still have synthesis gas as the main component.

The electrochemical electrolysis device of the present invention can electrolyze a cathode reactant and an anode reactant, and form a cathode mixture and an anode mixture respectively. Specifically, the cathode reactant includes carbon dioxide gas and a catholyte, and the anode reactant includes an anolyte. The half-reaction of cathode reactants at the cathode is: , as well as ;The half-reaction of the anode reactant at the anode is: . After electrolysis, the cathode mixture will contain carbon monoxide and hydrogen produced by the electrolysis reaction, liquid sodium hydroxide, and catholyte. The anode mixture includes chlorine gas produced by electrolysis and the anolyte.

Since carbon dioxide gas is introduced into the cathode of the present invention, there is no problem of low carbon dioxide conversion rate and unstable electrolysis reaction caused by the slow diffusion rate of carbon dioxide in the aqueous solution. Moreover, the cathode mixture produced by the electrolysis reaction includes a high content of synthesis gas, which can be used directly as fuel. Through the use of the absorption unit, the unelectrolyzed carbon dioxide in the cathode mixture can be absorbed to further obtain high-purity synthesis gas.

It can be seen from this that the carbon dioxide electrolysis system of the present invention can convert carbon dioxide into carbon monoxide and hydrogen at the cathode, not only decomposing greenhouse gases (carbon dioxide), but also producing synthetic gas (carbon monoxide and hydrogen) that can be used as fuel. Due to the high concentration of synthetic gas, it does not need to go through complicated separation or purification steps and can be directly used as fuel or the basic raw material for other chemicals. In other embodiments, the cathode reactant may also be a compound containing bicarbonate or carbonate.

The aforementioned catholyte may contain sodium hydroxide, sodium bromide, sodium bicarbonate, sodium sulfate, sodium phosphate, sodium hydrogenphosphate, lithium hydroxide, lithium bromide, lithium bicarbonate, lithium sulfate, lithium phosphate, lithium hydrogenphosphate, An aqueous electrolyte solution of potassium hydroxide, potassium bromide, potassium bicarbonate, potassium sulfate, potassium phosphate, potassium hydrogen phosphate or any combination thereof. In a preferred embodiment, the catholyte contains bicarbonate or carbonate. Preferably, the catholyte is an aqueous solution containing sodium bicarbonate. For example, carbon dioxide can be dissolved into an aqueous sodium hydroxide solution to form Sodium bicarbonate aqueous solution. Moreover, the concentration of the electrolyte in the catholyte is as low as 0.001M and as high as the saturation concentration of the electrolyte.

The aforementioned anolyte may contain sodium hydroxide, sodium bromide, sodium bicarbonate, sodium sulfate, sodium phosphate, sodium hydrogenphosphate, lithium hydroxide, lithium bromide, lithium bicarbonate, lithium sulfate, lithium phosphate, lithium hydrogenphosphate, An aqueous electrolyte solution of potassium hydroxide, potassium bromide, potassium bicarbonate, potassium sulfate, potassium phosphate, potassium hydrogen phosphate or any combination thereof. In a preferred embodiment, the anolyte contains chloride ions (especially salts containing chloride ions). Preferably, the anolyte is an aqueous solution containing sodium chloride. Moreover, the concentration of electrolyte in the anolyte is as low as 0.001M and as high as the saturation concentration of the electrolyte.

[First Embodiment]

Referring to Figure 1, a first embodiment of the present invention provides a carbon dioxide electrolysis system, which includes: electrochemical electrolysis equipment 1, a first reactant preparation unit 2, a second reactant preparation unit 3, a first Gas-liquid separation unit 4, a second gas-liquid separation unit 5 and absorption unit 6.

The electrochemical electrolysis device 1 is in fluid communication with the first reactant preparation unit 2 to receive the cathode reactant A1 provided by the first reactant preparation unit 2 . The electrochemical electrolysis device 1 is in fluid communication with the second reactant preparation unit 3 to receive the anode reactant A2 provided by the second reactant preparation unit 3 . The electrochemical electrolysis device 1 electrolyzes the cathode reactant A1 and the anode reactant A2, and forms a cathode mixture B1 and an anode mixture B2 respectively. Among them, the cathode reactant A1 is prepared by the first reactant preparation unit 2 after receiving the cathode electrolyte E1 and carbon dioxide gas, and the anode reactant A2 is prepared by the second reactant preparation unit 3 after receiving the anolyte E2 .

The electrochemical electrolysis device 1 is in fluid communication with the first gas-liquid separation unit 4 to separate the gas phase component and the liquid phase component in the cathode mixture B1. The cathode mixture B1 can be distinguished by the first gas-liquid separation unit 4 into a cathode gas mixture V1 and a cathode liquid mixture L1. Specifically, the cathode gas mixture V1 includes carbon dioxide, carbon monoxide and hydrogen. The cathode liquid mixture L1 contains liquid sodium hydroxide and the catholyte E1. That is to say, the cathode liquid mixture L1 contains metal ions, hydroxide ions or metal hydroxides. It can be seen from this that the carbon dioxide electrolysis system of the present invention can simultaneously produce a cathode gas mixture V1 and a cathode liquid mixture L1 with economic value.

The electrochemical electrolysis device 1 is in fluid communication with the second gas-liquid separation unit 5 to separate the gas phase component and the liquid phase component in the anode mixture B2. The anode mixture B2 can be distinguished by the second gas-liquid separation unit 5 into an anode gas mixture V2 and an anode liquid mixture L2. Specifically, the anode gas mixture V2 includes chlorine gas, and the anode liquid mixture L2 includes the anolyte E2.

The absorption unit 6 is in fluid communication with the first gas-liquid separation unit 4 to process the cathode gas mixture V1. The absorption unit 6 absorbs carbon dioxide in the cathode gas mixture V1 to separate carbon monoxide and hydrogen. Specifically, the catholyte E1 is passed into the absorption unit 6 and brought into contact with the cathode gas mixture V1. At this time, carbon dioxide will be dissolved in the catholyte E1 from the cathode gas mixture V1.

Therefore, after the cathode gas mixture V1 contacts the cathode electrolyte E1, a cathode gas product P1 and a reflux liquid R1 will be formed. Cathode gas product P1 includes carbon monoxide and hydrogen. The reflux liquid R1 contains the catholyte E1, liquid sodium hydroxide (or liquid alkali) and carbon dioxide. It is worth noting that liquid sodium hydroxide and carbon dioxide will react to form an aqueous sodium bicarbonate solution, which can be used as the catholyte E1. Therefore, the reflux liquid R1 can be returned to the electrochemical electrolysis device 1 and reused as the cathode reactant A1. In a preferred embodiment, the reflux liquid R1 is first transported to the first reactant preparation unit 2, and then transported to the electrochemical electrolysis equipment 1 after appropriate preparation. Specifically, the reflux liquid R1 contains bicarbonate, carbonate or hydroxide.

The electrochemical electrolysis equipment 1 and the absorption unit 6 can form a circulation pipeline, so that the carbon dioxide electrolysis system of the present invention can stably produce the cathode gas product P1 and the cathode liquid mixture L1 with economic value, and can improve the use of the cathode reactant A1 efficiency.

Please refer to FIGS. 2 and 3 together. The chemical electrolysis equipment 1 of the present invention includes a plurality of electrolysis units 10 . In the first embodiment, a plurality of electrolysis units 10 are arranged in series, and an insulating plate 13 is spaced between every two adjacent electrolysis units 10 . In some embodiments, the number of electrolysis units 10 is 3 to 30.

It should be noted that the electrolysis units 10 arranged in series are illustrated in FIG. 2 , but the actual application is not limited to this, and multiple electrolysis units 10 can also be arranged in parallel. For example, several electrolysis units 10 can first be arranged in series to form an electrolysis module, and then, several electrolysis modules can be connected in parallel to form an electrolysis assembly to increase the processing capacity of carbon dioxide gas and/or Increase the concentration of cathode gas product P1.

Please refer to FIGS. 2 and 3 . Each electrolysis unit 10 includes a cathode electrode 14 located in a cathode chamber 11 , an anode electrode 15 located in an anode chamber 12 , and anode electrode 14 sandwiched between the cathode electrode 14 and the anode electrode. 15 between an ion exchange membrane 20.

Each cathode chamber 11 is formed with an inlet 111 on an inlet side to receive the cathode reactant A1, and each cathode chamber 11 is formed with an outlet 112 on an outlet side to discharge the cathode mixture B1, and the inlet side and the outlet sides facing each other. Each anode chamber 12 is formed with an inlet 121 on an inlet side to receive the anode reactant A2, and each anode chamber 12 is formed with an outlet 122 on an outlet side to discharge the anode mixture B2, and the inlet side and the outlet sides facing each other.

In some embodiments, the inlets 111 of each cathode chamber 11 are connected to each other by a pipeline to inject the cathode reactant A1 at the same time, and the inlets 121 of each anode chamber 12 are connected to each other by another pipeline to inject the anode reactant A2 at the same time. . The inlet 111 of the cathode chamber 11 and the inlet 121 of the anode chamber 12 are not connected. Similarly, the outlets 112 of each cathode chamber 11 are connected to each other by a pipeline, so that the electrolysis products produced by each electrolysis unit 10 are combined to form the cathode mixture B1. The outlets 122 of each anode chamber 12 are connected to each other by another pipeline, so that the electrolysis products generated by each electrolysis unit 10 are combined to form an anode mixture B2. The outlet 112 of the cathode chamber 11 is not connected with the outlet 122 of the anode chamber 12 .

The inlets 111 and 121 can be formed at any position of the cathode chamber 11 or the anode chamber 12. Generally speaking, the inlets 111 and 121 are formed near the bottom of the cathode chamber 11 or the anode chamber 12. Moreover, compared with the positions of the inlets 111 and 121, the positions of the outlets 112 and 122 are located at a higher height. For example, the inlets 111 and 121 may be formed near the bottom of the electrolysis unit 10 , and the outlets 112 and 122 may be formed at half or more of the height of the electrolysis unit 10 . However, the present invention is not limited thereto.

Please refer to FIG. 3 . The cathode electrode 14 is disposed on the cathode chamber 11 . A cathode catalyst 141 is formed on the cathode electrode 14 on a plane facing the ion exchange membrane 20 to promote the reduction reaction. The other plane of the cathode electrode 14 is located in the cathode chamber 11 and is in contact with the cathode reactant A1. The anode electrode 15 is disposed on the anode chamber 12, and an anode catalyst 151 is formed on the anode electrode 15 on a plane facing the ion exchange membrane 20 to promote the oxidation reaction. The other plane of the anode electrode 15 is located in the anode chamber 12 and is in contact with the anode reactant A2. An external power source can apply electrical energy to the cathode electrode 14 and the anode electrode 15 to perform electrolysis.

In order to prevent the cathode electrode 14 of the electrolysis unit 10 from contacting the anode electrode 15 of the adjacent electrolysis unit 10, an insulating plate 13 is provided between the adjacent electrolysis units 10 to completely separate them. In this way, when an external voltage is applied to the cathode electrode 14 and the anode electrode 15, it can be ensured that the cathode electrode 14 does not come into contact with the anode electrode 15 to avoid short circuit.

In the present invention, the cathode electrode 14 may have a dense network structure, and the material forming the cathode electrode 14 may be a conductive material, such as metal or carbon material. The anode electrode 15 may have a dense network structure, and the material forming the anode electrode 15 may be a conductive material, such as metal or carbon material.

The cathode catalyst 141 may be various metals, metal compounds, alloys, carbon compounds containing at least one of heteroatoms or metals, or any combination thereof. The metal may be vanadium, chromium, manganese, iron, cobalt, nickel, copper, tin, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, iridium, platinum, gold, aluminum , indium, titanium, lead, bismuth, antimony, tellurium, lanthanum, cerium, neodymium or combinations thereof. Metal compounds include organic metal compounds and inorganic metal compounds, and cover metal halides, metal oxides and metal hydroxides. The carbon compound containing at least one of heteroatoms or metals may be a structure composed of nitrogen-containing graphite, nitrogen-containing graphene, or nitrogen-containing carbon tubes and metal atoms.

The anode catalyst 151 may be various metals, metal compounds, alloys, carbon compounds containing at least one of heteroatoms or metals, or any combination thereof. The metal may be vanadium, chromium, manganese, iron, cobalt, nickel, copper, tin, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, iridium, platinum, gold, aluminum , indium, titanium, lead, bismuth, antimony, tellurium, lanthanum, cerium, neodymium or combinations thereof. Metal compounds include organic metal compounds and inorganic metal compounds, and cover metal halides, metal oxides and metal hydroxides. The carbon compound containing at least one of heteroatoms or metals may be a structure composed of nitrogen-containing graphite, nitrogen-containing graphene, or nitrogen-containing carbon tubes and metal atoms.

The thickness of the ion exchange membrane 20 is 10 microns to 5000 microns. The ion exchange membrane 20 can be a cation exchange membrane, for example: polyethylene sulfonic acid, fullerene cross-linked polysulfonic acid, polyacrylic acid or perfluoroethylene disulfonic acid. cation exchange membrane; alternatively, the ion exchange membrane 20 may be an anion exchange membrane, for example: an anion exchange membrane containing polystyrene methyltrimethylammonium chloride or polyether.

[Second Embodiment]

Referring to Figure 4, a second embodiment of the present invention provides a carbon dioxide electrolysis system, which is similar to the carbon dioxide electrolysis system of the first embodiment. The main difference is that the carbon dioxide electrolysis system of the second embodiment further includes a first A liquid treatment unit 7 and a second liquid treatment unit 8 .

The first liquid treatment unit 7 is in fluid communication with the first gas-liquid separation unit 4 to receive and appropriately process the cathode liquid mixture L1. The cathode liquid mixture L1 can form a first treatment liquid R1* after being processed by the first liquid treatment unit 7. The main component of the first treatment liquid R1* is the catholyte E1. Therefore, the first treatment liquid R1* can be returned to The electrochemical electrolysis equipment 1 is reused as the cathode reactant A1. In a preferred embodiment, the first treatment liquid R1* can be transported to the first reactant preparation unit 2 first, and then transported to the electrochemical electrolysis equipment 1 after being appropriately prepared. Specifically, the reflux liquid R1* contains bicarbonate, carbonate or hydroxide.

The second liquid treatment unit 8 is in fluid communication with the second gas-liquid separation unit 5 to receive and appropriately process the anode liquid mixture L2. The anode liquid mixture L2 can form a second treatment liquid R2* after being processed by the second liquid treatment unit 8. The main component of the second treatment liquid R2* is the anolyte E2. Therefore, the second treatment liquid R2* can be returned to Electrochemical electrolysis equipment 1 is reused as anode reactant A2. In a preferred embodiment, the second treatment liquid R2* can be first transported to the second reactant preparation unit 3, and then transported to the electrochemical electrolysis equipment 1 after appropriate preparation.

[Third Embodiment]

Please refer to FIG. 5 and FIG. 6 together. The third embodiment of the present invention provides a carbon dioxide electrolysis system, which is similar to the carbon dioxide electrolysis system of the first embodiment. The main difference is that: the carbon dioxide electrolysis system of the third embodiment The first gas-liquid separation unit 4 and the second gas-liquid separation unit 5 are not included.

Please refer to FIG. 6 . In the third embodiment, each cathode chamber 11 has two outlets 112A and 112B, and the two outlets 112A and 112B are formed at different height positions. The higher outlet 112A can be used to discharge the cathode gas mixture V1, while the lower outlet 112B can be used to discharge the cathode liquid mixture L1. Each anode chamber 12 has two outlets 112A and 112B, and the two outlets 112A and 112B are formed at different height positions. The higher outlet 122A can be used to discharge the anode gas mixture V2, while the lower outlet 122B can be used to discharge the anode liquid mixture L2. In this way, the use of the first liquid treatment unit 7 and the second liquid treatment unit 8 can be omitted.

It is worth noting that when the carbon dioxide electrolysis system of the third embodiment is used, the liquid height in the cathode chamber 11 and the anode chamber 12 needs to be maintained in a half-full or more than half-full state in order to distinguish the cathode gas mixture V1 with the cathode liquid mixture L1, and the effect of distinguishing the anode gas mixture V2 from the anode liquid mixture L2.

In addition to the first gas-liquid separation unit 4 and the second gas-liquid separation unit 5, the carbon dioxide electrolysis system in the third embodiment has an electrochemical electrolysis device 1, a first reaction similar to the carbon dioxide electrolysis system in the first embodiment. The reaction product preparation unit 2, the second reactant preparation unit 3 and the absorption unit 6 are not described again.

[Fourth Embodiment]

Please refer to FIG. 7 . The fourth embodiment of the present invention provides a carbon dioxide electrolysis system, which is similar to the carbon dioxide electrolysis system of the third embodiment. The main difference is that the carbon dioxide electrolysis system of the fourth embodiment further includes a first Liquid treatment unit 7 and second liquid treatment unit 8 .

The first liquid treatment unit 7 is in fluid communication with the electrochemical electrolysis device 1 to receive and appropriately process the cathode liquid mixture L1. The cathode liquid mixture L1 can form a first treatment liquid R1* after being processed by the first liquid treatment unit 7. The main component of the first treatment liquid R1* is the catholyte E1. Therefore, the first treatment liquid R1* can be returned to The electrochemical electrolysis equipment 1 is reused as the cathode reactant A1. In a preferred embodiment, the first treatment liquid R1* can be transported to the first reactant preparation unit 2 first, and then transported to the electrochemical electrolysis equipment 1 after being appropriately prepared.

The second liquid treatment unit 8 is in fluid communication with the electrochemical electrolysis device 1 to receive and appropriately process the anode liquid mixture L2. The anode liquid mixture L2 can form a second treatment liquid R2* after being processed by the second liquid treatment unit 8. The main component of the second treatment liquid R2* is the anolyte E2. Therefore, the second treatment liquid R2* can be returned to Electrochemical electrolysis equipment 1 is reused as anode reactant A2. In a preferred embodiment, the second treatment liquid R2* can be first transported to the second reactant preparation unit 3, and then transported to the electrochemical electrolysis equipment 1 after appropriate preparation.

Please refer to Figure 8. The present invention also provides an electrolysis method of carbon dioxide, which includes: using an electrochemical electrolysis device to electrolyze a cathode reactant and an anode reactant to form a cathode mixture and an anode mixture respectively (step S1 ); use an absorption unit to process the cathode mixture, and divide the cathode mixture into a cathode gas product and a reflux liquid (step S2); transport the reflux liquid to a first reactant preparation unit (step S3); first reactant preparation unit After receiving the reflux liquid, the cathode reactant is provided to the electrochemical electrolysis device (step S4).

In step S1, the cathode reactant includes carbon dioxide gas and a cathode electrolyte, the anode reactant includes an anolyte, and the cathode mixture includes carbon monoxide, hydrogen, liquid sodium hydroxide and cathode electrolyte produced by the electrolysis reaction, and the anode mixture Includes chlorine gas and anolyte. In step S2, the cathode gas product includes carbon monoxide and hydrogen, which is synthesis gas. The reflux liquid includes catholyte, liquid sodium hydroxide and carbon dioxide, so it can be refluxed to the electrochemical electrolysis equipment through steps S3 to S4 to improve the carbon dioxide conversion rate of the carbon dioxide electrolysis method of the present invention. According to the above method, the present invention can convert carbon dioxide into synthetic gas that can be used as fuel, which not only alleviates the problem of greenhouse effect, but also provides renewable energy.

[Beneficial effects of the embodiment]

One of the beneficial effects of the present invention is that the carbon dioxide electrolysis system and method provided by the present invention can be achieved by "the cathode reactant A1 includes carbon dioxide or a compound containing carbonate or bicarbonate, and the cathode mixture B1 includes Carbon monoxide and hydrogen, the anode mixture B1 includes chlorine" and the technical solution of "the absorption unit 6 processes the cathode mixture B1 and separates a synthesis gas including carbon monoxide and hydrogen", and has a decomposable greenhouse gas (carbon dioxide), The effect is also produced of synthesis gases (carbon monoxide and hydrogen) that can be used as fuel, as well as an alkaline liquid product that has commercial uses.

Furthermore, the carbon dioxide electrolysis system and method of the present invention distinguishes the cathode mixture into a cathode gas product and a reflux liquid through "the absorption unit. The cathode gas product includes the synthesis gas, and the reflux liquid The technical solution of "refluxing the liquid to the electrochemical electrolysis equipment" can increase the content of synthesis gas in the cathode gas product and can be stably produced in a continuous manner.

The contents disclosed above are only preferred and feasible embodiments of the present invention, and do not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. within the scope of the patent.

1: Electrochemical electrolysis equipment 2: First reactant preparation unit 3: Second reactant preparation unit 4: First gas-liquid separation unit 5: Second gas-liquid separation unit 6: Absorption unit 7: First liquid handling unit 8: Second liquid handling unit A1: cathode reactant A2: Anode reactant B1: Cathode mixture B2: Anode mixture E1: catholyte E2: Anolyte V1: cathode gas mixture V2: anode gas mixture L1: cathode liquid mixture L2: anode liquid mixture P1: cathode gas product R1: Reflux liquid R1*: first treatment liquid R2*: Second treatment liquid 10:Electrolysis unit 11:Cathode chamber 111:Entrance 112, 112A, 112B: Exit 12:Anode chamber 121:Entrance 122, 122A, 122B: Exit 13:Insulation board 14:Cathode electrode 141:Cathode catalyst 15:Anode electrode 151:Anode catalyst 20:Ion exchange membrane

Figure 1 is a functional block diagram of a carbon dioxide electrolysis system according to the first embodiment of the present invention.

Figure 2 is a three-dimensional schematic diagram of the electrochemical electrolysis equipment of the present invention.

Figure 3 is a schematic side cross-sectional view of the electrochemical electrolysis equipment according to the first embodiment of the present invention.

Figure 4 is a functional block diagram of a carbon dioxide electrolysis system according to the second embodiment of the present invention.

Figure 5 is a functional block diagram of a carbon dioxide electrolysis system according to the third embodiment of the present invention.

Figure 6 is a schematic side cross-sectional view of the electrochemical electrolysis equipment according to the third embodiment of the present invention.

Figure 7 is a functional block diagram of a carbon dioxide electrolysis system according to the fourth embodiment of the present invention.

Figure 8 is a flow chart of the carbon dioxide electrolysis method of the present invention.

1: Electrochemical electrolysis equipment 2: First reactant preparation unit 3: Second reactant preparation unit 4: First gas-liquid separation unit 5: Second gas-liquid separation unit 6: Absorption unit A1: cathode reactant A2: Anode reactant B1: Cathode mixture B2: Anode mixture E1: catholyte E2: Anolyte V1: cathode gas mixture V2: anode gas mixture L1: cathode liquid mixture L2: anode liquid mixture P1: cathode gas product R1: Reflux liquid

Claims (18)

An electrolysis system for carbon dioxide, which includes: an electrochemical electrolysis device that electrolyzes a cathode reactant and an anode reactant to form a cathode mixture and an anode mixture respectively; wherein the cathode reactant includes carbon dioxide or contains Bicarbonate or carbonate compound, the cathode mixture includes carbon dioxide, carbon monoxide and hydrogen, the anode mixture includes chlorine; a first gas-liquid separation unit, the first gas-liquid separation unit is fluidly connected to the electrochemical Electrolysis equipment, the first gas-liquid separation unit differentiates the cathode mixture into a cathode gas mixture and a cathode liquid mixture; and an absorption unit is in fluid communication with the first gas-liquid separation unit to process the cathode gas mixture, and separate a synthesis gas composed of the carbon monoxide and the hydrogen. The carbon dioxide electrolysis system according to claim 1, further comprising: a first reactant preparation unit fluidly connected between the electrochemical electrolysis equipment and the absorption unit, The first reactant preparation unit receives a reflux liquid and provides the cathode reactant to the electrochemical electrolysis device. The carbon dioxide electrolysis system of claim 1, wherein the cathode liquid mixture contains metal ions, hydroxide ions or metal hydroxides. The carbon dioxide electrolysis system according to claim 1, further comprising: a first liquid treatment unit, the first liquid treatment unit is in fluid communication with the electrochemical electrolysis equipment, the first liquid treatment unit processes the cathode The liquid mixture is mixed to produce a first treatment liquid, and the first treatment liquid is returned to the electrochemical electrolysis device. The carbon dioxide electrolysis system according to claim 4, further comprising: a first reactant preparation unit, the first reactant preparation unit is fluidly connected to the Between the electrochemical electrolysis equipment and the first liquid treatment unit, the first reactant preparation unit receives the first treatment liquid and provides the cathode reactant to the electrochemical electrolysis equipment. The carbon dioxide electrolysis system of claim 1, wherein the anode mixture includes an anode gas mixture and an anode liquid mixture. The carbon dioxide electrolysis system according to claim 6, further comprising: a second gas-liquid separation unit, the second gas-liquid separation unit is fluidly connected to the electrochemical electrolysis equipment, and the second gas-liquid separation unit The anode mixture is divided into the anode gas mixture and the anode liquid mixture. The carbon dioxide electrolysis system of claim 6, further comprising: a second liquid treatment unit, the second liquid treatment unit is in fluid communication with the electrochemical electrolysis equipment, and the second liquid treatment unit processes the anode The liquid mixture is mixed to produce a second treatment liquid, and the second treatment liquid is returned to the electrochemical electrolysis device. The carbon dioxide electrolysis system according to claim 8, further comprising: a second reactant preparation unit, the second reactant preparation unit is fluidly connected between the electrochemical electrolysis equipment and the second liquid treatment unit. , the second reactant preparation unit receives the second treatment liquid and provides the anode reactant to the electrochemical electrolysis device. The carbon dioxide electrolysis system of claim 1, wherein the electrochemical electrolysis equipment includes a plurality of electrolysis units; wherein each electrolysis unit includes a cathode electrode located in a cathode chamber, an anode electrode located in an anode chamber. an anode electrode and an ion exchange membrane sandwiched between the cathode electrode and the anode electrode. The carbon dioxide electrolysis system of claim 10, wherein the cathode electrode is disposed in the cathode chamber, a cathode catalyst is formed on the cathode electrode, and the anode electrode is disposed in the anode chamber, so The anode electrode is formed with An anode catalyst, each two adjacent electrolysis units are separated by an insulating plate; wherein, the material of the cathode catalyst includes iron, cobalt, nickel, copper, ruthenium, rhodium, silver, iridium, platinum, gold , titanium or a carbon compound containing any of the above metals, and the material of the anode catalyst contains ruthenium, rhodium, iridium, titanium or a metal halide, metal oxide or metal hydroxide containing any of the above metals. The carbon dioxide electrolysis system of claim 9, wherein the cathode chamber has an inlet for receiving the cathode reactant and an outlet for discharging the cathode mixture, and the anode chamber has an an inlet to receive the anode reactants and an outlet to discharge the anode mixture. The carbon dioxide electrolysis system of claim 9, wherein the cathode chamber has an inlet to receive the cathode reactant and two outlets to discharge the cathode mixture, and the anode chamber has an inlet to receive the cathode reactant. the anode reactants and two outlets to discharge the anode mixture. The carbon dioxide electrolysis system of claim 1, wherein the cathode reactant further includes a catholyte, the catholyte contains bicarbonate or carbonate; wherein the anode reactant further includes a cathode. An anolyte containing chloride ions. The carbon dioxide electrolysis system of claim 1, wherein the anolyte includes salts containing chloride ions. An electrolysis method of carbon dioxide, which includes: using an electrochemical electrolysis device to electrolyze a cathode reactant and an anode reactant to form a cathode mixture and an anode mixture respectively; wherein the cathode reactant includes carbon dioxide or carbonate-containing Or a compound of bicarbonate, the cathode mixture includes carbon dioxide, carbon monoxide and hydrogen, the anode mixture includes chlorine; the cathode mixture is divided into a cathode gas mixture and a cathode liquid mixture by a first gas-liquid separation unit; and An absorption unit is used to process the cathode gas mixture to separate a synthesis gas composed of carbon monoxide and hydrogen. The electrolysis method of carbon dioxide according to claim 16, further comprising: transporting a reflux liquid to a first reactant preparation unit, and the first reactant preparation unit provides the cathode reactant to the electrochemical electrolysis equipment. The electrolysis method of carbon dioxide according to claim 16, wherein the cathode liquid mixture contains metal ions, hydroxide ions or metal hydroxides.

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