Electrochemical reactor with alternately assembled negative and positive membrane electrodes

Abstract

The utility model discloses an electrochemical reactor with alternately assembled negative and positive membrane electrodes, and belongs to the field of electrochemistry. The reactor consists of a clamp, a bipolar plate, a partition plate, a composite membrane electrode and filler, and is provided with a cathode inlet, a cathode outlet, an anode inlet, an anode outlet, a reactor inlet and a reactor outlet. Wherein the composite membrane electrode is formed by compounding a plurality of layers of materials and is divided into a negative membrane electrode and a positive membrane electrode according to the types of ions generated by catalysis, and the negative membrane electrode and the positive membrane electrode are alternately assembled in the reactor assembly process. The reactor can be applied to an oxygen reduction reaction and an electro-thermal coupling reaction.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of electrochemical catalysis, and particularly relates to an electrochemical reactor with alternating assembly of negative and positive membrane electrodes and application of the electrochemical reactor in electrocatalytic reaction and "electric-thermal" coupling reaction. BACKGROUND

[0002] Traditional chemical processes have high energy consumption, complex process, serious pollution and low safety. With the development of green renewable energy, green electricity resources are increasingly abundant. Introducing electricity into traditional chemical production processes, using electrocatalysis to realize chemical process reengineering, and then reducing energy consumption, simplifying the process, reducing pollution and improving safety are inevitable trends in the development of chemical engineering.

[0003] Common fuel cell reactors and water electrolysis hydrogen production reaction tanks generally use membrane electrodes based on cation exchange membranes for assembly, thereby realizing one-way transfer of protons from the anode to the cathode. However, both types of reactors are subject to the type of ion exchange membrane and are only suitable for proton transfer reactions, lacking universality and expandability. With the development of anion exchange membranes and surface hydrophobic processes, anion membrane electrodes and membraneless electrodes have also gradually matured, making it possible for anions or molecules to transfer within the reactor, but subject to the existing reactor structure and assembly method, effective coupling production cannot be achieved.

[0004] The annual demand for hydrogen peroxide in China has exceeded tens of millions of tons, and the output value has reached hundreds of billions. At present, most hydrogen peroxide production enterprises still use the traditional anthraquinone process. This process requires a series of operations such as hydrogenation, oxidation, extraction and purification to produce hydrogen peroxide, while the electrocatalytic process for producing hydrogen peroxide can realize the direct synthesis process from hydrogen and oxygen to hydrogen peroxide, and can be used immediately, has low energy consumption, small risk and simple process. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing an electrochemical reactor with alternating assembly of negative and positive membrane electrodes and an application method thereof. The reactor in the utility model has simple structure, high safety, convenient assembly, strong adaptability and rich expandability. The application of the reactor in the utility model is for preparing hydrogen peroxide and olefin epoxidation.

[0006] The purpose of the utility model can be achieved by the following technical solutions:

[0007] An electrochemical reactor with alternating assembly of negative and positive membrane electrodes, the reactor comprising two clamps, one of the clamps being provided with an anode outlet and an anode inlet, and the other clamp being provided with a cathode outlet and a cathode inlet; N+2 bipolar plates are arranged between the two clamps, wherein N is an integer greater than or equal to 0;

[0008] The composite membrane positive electrode and the composite membrane negative electrode are arranged between the connected bipolar plates, and a baffle is arranged between the composite membrane positive electrode and the composite membrane negative electrode, and the baffle is provided with a reactor inlet and a reactor outlet.

[0009] In the technical scheme of the utility model, N is an integer of 0-100.

[0010] In the technical scheme of the utility model, the baffle is provided with filler, the filler is composed of solid electrolyte and powder catalyst mixed in proportion, the solid electrolyte accounts for 0.5-100% of the mass of the filler; the solid electrolyte is polymer electrolyte and oxide electrolyte, and the powder catalyst is molecular sieve catalyst, carbon-based catalyst or noble metal catalyst.

[0011] Preferably, the solid electrolyte is ion exchange resin DOWEX 50W*4, and the powder catalyst is titanium-silicon molecular sieve MACKLIN TS-1.

[0012] In the technical scheme of the utility model, the composite membrane positive electrode and the composite membrane negative electrode are both composed of diffusion layer, catalytic layer and transfer layer.

[0013] The diffusion layer is one of porous titanium plate, carbon paper, carbon cloth and carbon felt.

[0014] The catalytic layer is electrocatalyst, and the catalyst is hydrogen oxidation reaction catalyst, water oxidation reaction catalyst or oxygen reduction reaction catalyst.

[0015] The transfer layer is proton exchange membrane, polytetrafluoroethylene coating, surface modification coating of the catalytic layer or anion exchange membrane, and the effective area of the membrane electrode is 4-10000 cm 2 .

[0016] In the technical scheme of the utility model, the catalytic layer of the composite membrane negative electrode is the oxygen reduction catalyst prepared by the method recorded in embodiment 1 in the content disclosed by CN117431559A.

[0017] In the technical scheme of the utility model, the catalytic layer of the composite membrane positive electrode is hydrogen oxidation reaction catalyst MACKLIN 20% platinum carbon and water oxidation reaction catalyst Premetek 20% ruthenium carbon.

[0018] In the technical scheme of the utility model, the transfer layer is proton exchange membrane composite and anion exchange membrane.

[0019] In the technical scheme of the utility model, the clamps are fixed by bolts.

[0020] In the technical scheme of the utility model, the normal thickness of the baffle is 0.5-10 mm.

[0021] An oxidation reaction method using an electrochemical reactor assembled with alternating cathode and cation membrane electrodes, characterized in that the anode inlet feed is hydrogen or water, the cathode inlet feed is oxygen, the cathode undergoes an oxygen reduction reaction, and the reactor feed is pure water, which directly synthesizes hydrogen peroxide with the protons generated at the anode.

[0022] Alternatively, the feed at the anode inlet can be hydrogen or water, and the feed at the cathode inlet can be oxygen. An oxygen reduction reaction occurs at the cathode, while the feed at the reactor is a solvent. If the oxide is in the gas phase, it is mixed with oxygen and fed through the cathode inlet. If the oxide is in the liquid phase, it is mixed with solvent and fed through the reactor inlet. The oxidation reaction is achieved through "electro-thermal" coupling.

[0023] In this utility model, the clamp consists of an end plate and bolts, and its function is to fix the core components of the reactor, ensuring that the components are directly and tightly fitted to ensure airtightness. Its assembly pressure is 0.5-10MPa.

[0024] In this utility model, the bipolar plate has fluid channels on both sides and is composed of conductive materials such as graphite or metal.

[0025] In this utility model, the partition material is one or more of polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UPE), perfluoroalkoxy copolymer (PFA), polypropylene (PP), and polyvinyl chloride (PVC).

[0026] The beneficial effects of the technical solution provided by this utility model example:

[0027] (1) The reactor described in this utility model has a simple structure, high safety, convenient assembly, and strong adaptability. Compared with fuel cell reactors and water electrolysis hydrogen production reactors, it has rich scalability and can realize the transfer of anions or molecules in the reactor, thereby generating effective coupling reactions and stable and efficient production.

[0028] (2) The application method described in this utility model is simple to operate and has mild conditions, which greatly simplifies the anthraquinone process and the olefin epoxidation process, and realizes the one-step production of hydrogen peroxide or olefin epoxide. Attached Figure Description

[0029] Figure 1 This is a diagram showing the dismantling of a reactor (taking a 2-layer reactor as an example).

[0030] Figure 2 The completed blueprints for the reactor assembly (taking a 6-layer reactor as an example).

[0031] Figure 3 The results are from the 500-hour test of the reactor outlet products in Example 1.

[0032] Figure 4The results are from the 200-hour test of reactor outlet products in Example 3.

[0033] In the figure: 1—clamp; 2—partition; 3—bipolar plate; 4—packing; 5—composite membrane electrode (anode); 6—composite membrane electrode (cathode); 7—anode outlet; 8—anode inlet; 9—cathode outlet; 10—cathode inlet; 11—reactor inlet; 12—reactor outlet; 13—bolt.

[0034] Table 1 shows the reactor outlet product concentration detection results in Example 1, Comparative Example 1, Comparative Example 2, and Example 2.

[0035] Table 2 shows the test results of the H2O2 content, acidity, color, total organic carbon (TOC), acid radical ions, and metal impurities in the reactor outlet products of Example 1.

[0036] Table 3 shows the reactor outlet product yield test results in Examples 3 and 4. Detailed Implementation

[0037] The following embodiments will further illustrate the present invention, but the content of the present invention is not limited thereto. Unless otherwise specified, the reagents used in the following embodiments are conventional reagents available in the art; the methods used, unless otherwise specified, are conventional methods in the art.

[0038] The reactor assembly described in this utility model is as follows:

[0039] The fixture, bipolar plate, composite membrane electrode, separator, etc. are used as... Figure 1 As shown, the components are stacked sequentially. The filler is then filled into the cavity formed by the separator and the composite membrane electrode. A normal pressure of 2 MPa relative to the clamp is applied to ensure a tight seal, and the assembly is secured with bolts. Details are as follows:

[0040] The reactor includes two clamps, one of which has an anode outlet 7 and an anode inlet 8, and the other has a cathode outlet 9 and a cathode inlet 10. Several bipolar plates 3 are arranged between the two clamps. A composite membrane anode 5 and a composite membrane cathode 6 are arranged between the connected bipolar plates 3. A partition 2 is arranged between the composite membrane anode 5 and the composite membrane cathode 6. The partition 2 has a reactor inlet 11 and a reactor outlet 12.

[0041] The clamps are fixed together with bolts. The normal thickness of the partition (2) is 5mm.

[0042] Example 1:

[0043] When used in the production of hydrogen peroxide, the effective area of ​​the membrane electrode in the reactor is 900 cm². 2The reactor has 6 layers (including 7 bipolar plates 3 and 6 separators 2). The separators 2 are made of PTFE with a thickness of 2mm. The filler in the separators is 100% solid electrolyte (DOWEX 50W*4 ion exchange resin). The composite membrane anode 5 uses carbon paper (SGL 36BB), a platinum-carbon catalyst (MACKLIN 20% platinum-carbon hydroxide catalyst), and a proton exchange membrane (DuPont N212). The composite membrane cathode 6 uses carbon paper (SGL 36BB), an oxygen reduction catalyst (prepared by the method described in Example 1 of CN117431559A), and an anion exchange membrane (FuMA-Tech). After assembly, the reactor was cleaned with ultrapure water for 24 hours. The reactor was placed in a clean room, hydrogen was introduced into the anode, oxygen was introduced into the cathode, and water flowed into the reactor. A voltage of 12V was applied to the anode and cathode of the reactor, and the product at the reactor outlet was measured for testing.

[0044] Comparative Example 1:

[0045] Simply change the effective area of ​​the membrane electrode to 1 cm² 2 The number of bipolar plates is 2, and the other processes are the same as in Example 1.

[0046] Comparative Example 2:

[0047] The only difference is that the anion electrode is replaced with a composite of carbon paper and oxygen reduction catalyst (CN117431559A Example 1), while the rest of the process is the same as in Example 1.

[0048] Example 2:

[0049] When used in the production of hydrogen peroxide, the effective area of ​​the membrane electrode in the reactor is 100 cm². 2 The reactor has four layers (including five bipolar plates 3 and four separators 2). The separators 2 are made of PEEK material with a thickness of 2 mm. The filler in the separators is 100% solid electrolyte (DOWEX 50W x 4 ion exchange resin). The composite membrane anode 5 is composed of carbon paper (SGL 36BB), a ruthenium carbon catalyst (Premetek 20% ruthenium carbon catalyst for water oxidation reaction), and a proton exchange membrane (DuPont N212). The composite membrane cathode 6 is composed of carbon paper (SGL 36BB), an oxygen reduction catalyst (prepared by the method described in Example 1 of CN117431559A), and an anion exchange membrane (FuMA-Tech). A 0.1M sulfuric acid solution is introduced into the anode, oxygen is introduced into the cathode, and water is introduced into the reactor. An 8V voltage is applied to the reactor anode and cathode, and the product at the reactor outlet is measured.

[0050] Example 3:

[0051] When used for electro-thermal coupling to achieve the propylene oxidation reaction, the effective area of ​​the membrane electrode in the reactor is 100 cm².2 The reactor has four layers (including five bipolar plates 3 and four separators 2). Separators 2 are made of PEEK material with a thickness of 2 mm. The filler in the separators is a mixture of solid electrolyte (DOWEX 50W x 4 ion exchange resin) and powdered catalyst (MACKLIN TS-1 titanium silicon molecular sieve) in a certain proportion (resin mass ratio 99%). The composite membrane anode 5 uses carbon paper (SGL 36BB), platinum-carbon catalyst (MACKLIN 20% platinum-carbon hydroxide catalyst), and proton exchange membrane (DuPont N212). The composite membrane cathode 6 uses carbon paper (SGL 28BC), oxygen reduction catalyst (CN117431559A Example 1), and is surface modified with tetraethylammonium hydroxide. Hydrogen gas is introduced into the anode, a mixture of oxygen and propylene gas is introduced into the cathode, and methanol is introduced into the reactor. An 8V voltage is applied to the reactor anode and cathode, and the product at the reactor outlet is measured.

[0052] Example 4:

[0053] When used for "electro-thermal" coupling to achieve ethylene oxidation, only the oxygen and propylene mixture is replaced with an oxygen and ethylene mixture; the rest of the process is the same as in Example 3.

[0054] Figure 1 , Figure 2 The reactor structure and assembly method in Example 1 are illustrated using a 6-layer reactor as an example. Figure 3 This demonstrates that the reactor in Example 1 exhibits good stability when used for hydrogen peroxide production. Figure 4 The reactor used in Example 3 for the olefin oxidation process also exhibits good stability. Table 1 shows that different reactor sizes significantly affect the concentration of the effluent product. Table 2 shows that improvements to the reactor material and pipelines enable the hydrogen peroxide product to meet the UP-4 grade hydrogen peroxide standard (HG / T 5736-2020). Table 3 shows that the reactor can achieve the oxidation of various olefins through an electro-thermal coupled reaction.

[0055] Table 1 shows the reactor outlet product concentration detection results in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example 2.

[0056]

[0057] Table 2 shows the test results of the H2O2 content, acidity, color, total organic carbon (TOC), acid radical ions, and metal impurities in the reactor outlet products of Example 1.

[0058]

[0059]

[0060]

[0061] Table 3 shows the reactor outlet product yield test results in Examples 3 and 4.

[0062]

Claims

1. An electrochemical reactor with alternating cathode and cation membrane electrodes, characterized in that, The reactor includes two clamps, one of which has an anode outlet (7) and an anode inlet (8), and the other clamp has a cathode outlet (9) and a cathode inlet (10); N+2 bipolar plates (3) are provided between the two clamps, where N is an integer greater than or equal to 0; A composite membrane anode (5) and a composite membrane cathode (6) are provided between the connected bipolar plates (3). A partition (2) is provided between the composite membrane anode (5) and the composite membrane cathode (6). A reactor inlet (11) and a reactor outlet (12) are provided on the partition (2).

2. The electrochemical reactor with alternating cathode and cation membrane electrodes according to claim 1, characterized in that, N is an integer from 0 to 100.

3. The electrochemical reactor with alternating cathode and cation membrane electrodes according to claim 1, characterized in that, The clamps are fixed together with bolts.

4. The electrochemical reactor with alternating cathode and cation membrane electrodes according to claim 1, characterized in that, The normal thickness of the partition (2) is 0.5-10mm.

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