Self-breathing diaphragm-free hydrogen peroxide electro-synthesis system

Abstract

The utility model discloses a kind of self-breathing diaphragm-free hydrogen peroxide electric synthesis systems, it is related to electrochemistry technical field.The system includes raw material pretreatment area, product collection area, electrolytic reaction zone, power supply area and gas purging area;Raw material pretreatment area is equipped with electrolyte storage tank, make-up pump, delivery pump, electrolyte raw material storage tank and high concentration product feed pump, electrolytic reaction zone is equipped with membraneless electrocatalytic reactor, membraneless electrocatalytic reactor includes anode catalytic electrode and cathode catalytic electrode, cathode catalytic electrode uses self-breathing three-dimensional porous electrode.The system of the utility model uses self-breathing diaphragm-free electrocatalysis method, by air self-suction directly utilizes ambient oxygen to realize hydrogen peroxide in-situ synthesis, significantly reduce the system energy consumption, while eliminating the dependence on proton exchange membrane, and can construct dynamic pH buffering mechanism to realize "interface proton dynamic balance", improve the ion concentration gradient problem of electrochemical device.

Description

Technical Field

[0001] This utility model relates to the field of electrochemical technology, specifically to a self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system. Background Technology

[0002] Hydrogen peroxide (H2O2) possesses diverse oxidizing properties and holds immense potential as an energy carrier, making it highly valuable for applications across various scientific fields. However, the primary method for large-scale industrial production of hydrogen peroxide remains the anthraquinone process. This process not only consumes large quantities of fossil fuels but also generates significant carbon emissions (approximately 3 tons of CO2 per ton of H2O2) and organic byproduct emissions.

[0003] Electrochemical two-electron oxygen reduction reaction (2e - ORR (Organic Renewable Energy) offers a more flexible and safer alternative for the decentralized and sustainable production of H2O2 from the Earth’s abundant O2 and H2O resources, utilizing renewable energy.

[0004] However, traditional submersible electrodes are limited by the low solubility of oxygen in water (8.1–8.5 mg / L at 25°C) and its relatively small diffusion coefficient (approximately 1.96–2.56 × 10⁻⁶). -9 m 2 The lack of an effective gas transport channel inside the reactor results in extremely low oxygen utilization (<1%), severely impacting H2O2 generation efficiency. Furthermore, developing a diaphragmless reactor design is a key strategy for improving system stability. It avoids performance degradation caused by the chemical degradation of the proton exchange membrane due to the conversion of H2O2 generated at the cathode into hydroxyl radicals (·OH), while also significantly reducing the system's ohmic impedance.

[0005] Therefore, a system that combines efficient gas channels with a stable structure and reactor is crucial for achieving efficient and stable electrosynthesis of hydrogen peroxide. Utility Model Content

[0006] The main purpose of this invention is to provide a self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system to overcome the problems of low oxygen utilization, insufficient system stability, and high energy consumption in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system includes a raw material pretreatment zone, a product collection zone, an electrolysis reaction zone, a power supply zone, and a gas purging zone;

[0009] The raw material pretreatment area is equipped with an electrolyte storage tank, a feed pump, a transfer pump, an electrolyte raw material storage tank, and a high-concentration product feed pump. The top of the electrolyte storage tank is equipped with a high-concentration product inlet, and the side is equipped with a high-concentration product outlet, an electrolyte raw material inlet, and an electrolyte outlet. The high-concentration product inlet is connected to the high-concentration product feed pump, and the high-concentration product outlet is connected to the second finished product tank in the product collection area. The electrolyte raw material inlet is connected to the electrolyte raw material storage tank through the feed pump, and the electrolyte outlet is connected to the electrolysis reaction area through the transfer pump.

[0010] The electrolysis reaction zone is equipped with a membrane-free electrocatalytic reactor, which includes an anode catalytic electrode and a cathode catalytic electrode. The cathode catalytic electrode is a self-breathing three-dimensional porous electrode. The anode and cathode catalytic electrodes are respectively connected to the power supply zone. The membrane-free electrocatalytic reactor is equipped with an electrolyte inlet, an electrolyte outlet, and a gas inlet. The electrolyte inlet is connected to the delivery pump, and the electrolyte outlet is connected to a product output pipeline. The product output pipeline is connected to a circulation pipeline and a flow pipeline. The circulation pipeline is connected to the high-concentration product feed pump, and the flow pipeline is connected to the first finished product tank in the product collection zone. The gas inlet is connected to the gas purging zone.

[0011] Furthermore, the electrolyte storage tank is connected to a concentration sensor, which is used to detect the concentration of hydrogen peroxide in the electrolyte storage tank.

[0012] Furthermore, the flow rates of the feed pump and the delivery pump are 5–80 mL / min.

[0013] Furthermore, the product collection area is equipped with a first finished product tank, a second finished product tank, a first peristaltic pump, and a second peristaltic pump. The flow pipeline is connected to the first finished product tank through the first peristaltic pump, and the high-concentration product outlet is connected to the second finished product tank through the second peristaltic pump.

[0014] The first finished product tank is a low-concentration finished product tank, and the second finished product tank is a high-concentration finished product tank.

[0015] Furthermore, the membrane-free electrocatalytic reactor is connected to a temperature control unit and a pressure gauge.

[0016] Furthermore, the anode catalytic electrode is connected to the positive electrode of the power supply region, and the cathode catalytic electrode is connected to the negative electrode of the power supply region.

[0017] Furthermore, the gas purging zone is equipped with an air pump and a gas flow valve. The air pump is used to provide purging gas with a flow rate of 2 to 20 mL / min, and the purging gas is introduced into the gas inlet through the gas flow valve.

[0018] Furthermore, the anode catalytic electrode is any one of an iridium-tantalum electrode, a platinum electrode, a ruthenium-iridium electrode, a graphite electrode, or a titanium suboxide electrode, and the cathode catalytic electrode is an electrode with two or more of the following materials loaded on its surface: carbon nanotubes, carbon black, graphite, or graphene. The distance between the anode catalytic electrode and the cathode catalytic electrode is 5–40 mm. The anode catalytic electrode is located near the electrolyte inlet, and the cathode catalytic electrode is located near the electrolyte outlet.

[0019] Furthermore, the cathode catalytic electrode has a hydrophobicity of level 1 to 3, and the hydrophobicity of the cathode catalytic electrode gradually decreases from the air-facing side to the electrolyte-facing side. The contact angle of the cathode catalytic electrode on the air-facing side is 135° to 155°, and the contact angle on the electrolyte-facing side is 110° to 125°.

[0020] Furthermore, the electrolyte storage tank stores any one or two of the following: a strong base-weak acid salt solution, a strong acid-strong base salt solution, or an acidic salt solution. The strong base-weak acid salt is any one of sodium carbonate, disodium hydrogen phosphate, sodium citrate, potassium carbonate, potassium dihydrogen phosphate, or potassium citrate. The acidic salt is any one of sodium bicarbonate, calcium dihydrogen phosphate, sodium dihydrogen phosphate, potassium bicarbonate, dipotassium hydrogen phosphate, or sodium bisulfate. The strong acid-strong base salt is any one of sodium chloride, sodium sulfate, potassium chloride, or potassium sulfate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The cathode catalytic electrode adopts a self-breathing three-dimensional porous electrode. The hydrophobic microenvironment inside the self-breathing three-dimensional porous electrode forms a gas transport channel to achieve air self-intake, efficiently constructing a gas-liquid-solid three-phase interface, significantly improving oxygen mass transfer efficiency, promoting in-situ H2O2 synthesis and reducing system energy consumption. The gas purging zone effectively removes the self-breathing three-dimensional porous electrode through directional airflow, avoiding the problem of capillary droplets blocking the gas diffusion channel caused by the internal and external pressure difference after the electrocatalytic reaction. This ensures that ambient oxygen can smoothly reach the reaction site through natural diffusion, thereby maintaining the self-breathing function of the cathode catalytic electrode and ensuring the continuous and efficient progress of the electrochemical reaction.

[0023] The use of a membrane-free electrocatalytic reactor avoids the problem of proton exchange membranes being derivatized into hydroxyl radicals (·OH) by H2O2, fundamentally preventing the performance degradation caused by chemical degradation, and significantly reducing the ohmic impedance of the system.

[0024] The electrolyte provided in the raw material pretreatment zone significantly suppresses the ion concentration gradient phenomenon caused by pH dynamic fluctuations at the electrode / solution interface, which is beneficial to improving the H2O2 generation efficiency.

[0025] By setting up feed pumps and delivery pumps, and by precisely adjusting the flow rate of the delivery pumps that deliver electrolyte / products to the electrolysis reaction zone, it is not only beneficial to remove H2O2 from the electrode surface and reduce the decomposition of H2O2, but also helps to reduce the change in electric field gradient caused by the migration of reactants / products. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0027] Explanation of reference numerals in the attached diagram: 1. Raw material pretreatment area; 2. Product collection area; 3. Electrolysis reaction area; 4. Power supply area; 5. Gas purging area; 11. Electrolyte storage tank; 12. Feed pump; 13. Transfer pump; 14. Electrolyte raw material storage tank; 15. High-concentration product feed pump; 111. High-concentration product inlet; 112. High-concentration product outlet; 113. Electrolyte raw material inlet; 114. Concentration sensor; 115. Electrolyte outlet; 21. First finished product tank; 22. Second finished product tank; 23. First peristaltic pump; 24. Second peristaltic pump; 31. Temperature control unit; 32. Pressure gauge; 33. Membrane-free electrocatalytic reactor; 331. Anode catalytic electrode; 332. Cathode catalytic electrode; 333. Electrolyte inlet; 334. Electrolyte outlet; 335. Gas inlet; 51. Purge gas; 52. Gas flow valve. Detailed Implementation

[0028] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0029] Combination Figure 1 This embodiment provides a self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system, including a raw material pretreatment zone 1, a product collection zone 2, an electrolysis reaction zone 3, a power supply zone 4, and a gas purging zone 5.

[0030] The raw material pretreatment area 1 is equipped with an electrolyte storage tank 11, a feed pump 12, a transfer pump 13, an electrolyte raw material storage tank 14, and a high-concentration product feed pump 15. The top of the electrolyte storage tank 11 is equipped with a high-concentration product inlet 111, and the side is equipped with a high-concentration product outlet 112, an electrolyte raw material inlet 113, and an electrolyte outlet 115. The high-concentration product inlet 111 is connected to the high-concentration product feed pump 15, and the high-concentration product outlet 112 is connected to the second finished product tank 22 of the product collection area 2. The electrolyte raw material inlet 113 is connected to the electrolyte raw material storage tank 14 through the feed pump 12, and the electrolyte outlet 115 is connected to the electrolysis reaction area 3 through the transfer pump 13. The electrolyte storage tank 11 is connected to a concentration sensor 114, which is used to detect the concentration of hydrogen peroxide in the electrolyte storage tank 11.

[0031] Specifically, the flow rates of the feed pump 12 and the transfer pump 13 are 5–80 mL / min.

[0032] Product collection area 2 is equipped with a first finished product tank 21, a second finished product tank 22, a first peristaltic pump 23 and a second peristaltic pump 24. The flow pipeline 336 is connected to the first finished product tank 21 through the first peristaltic pump 23, and the high-concentration product outlet 112 is connected to the second finished product tank 22 through the second peristaltic pump 24. Among them, the first finished product tank 21 is a low-concentration finished product tank, and the second finished product tank 22 is a high-concentration finished product tank.

[0033] The electrolysis reaction zone 3 is equipped with a temperature control unit 31, a pressure gauge 32, and a membraneless electrocatalytic reactor 33. The membraneless electrocatalytic reactor 33 includes an anode catalytic electrode 331 and a cathode catalytic electrode 332. The cathode catalytic electrode 332 is a self-breathing three-dimensional porous electrode. The anode catalytic electrode 331 and the cathode catalytic electrode 332 are respectively connected to the power supply zone 4. The membraneless electrocatalytic reactor 33 is equipped with an electrolyte inlet 333, an electrolyte outlet 334, and a gas inlet 335. The electrolyte inlet 333 is connected to the delivery pump 13. The electrolyte outlet 334 is connected to the product output pipeline 338. The product output pipeline 338 is connected to the circulation pipeline 337 and the overflow pipeline 336. The circulation pipeline 337 is connected to the high-concentration product feed pump 15. The overflow pipeline 336 is connected to the first finished product tank 21 of the product collection zone 2. The gas inlet 335 is connected to the gas purging zone 5.

[0034] Specifically, the temperature control unit 31 and the pressure gauge 32 are both connected to the membraneless electrocatalytic reactor 33. The temperature control unit 31 adjusts the heating / cooling power in real time through a PID algorithm to control the temperature of the reaction system to 25-35°C. The pressure gauge 32 monitors the pressure of the membraneless electrocatalytic reactor 33 in real time and adjusts the flow rate of the delivery pump to maintain the stability of the reaction interface.

[0035] The power supply zone 4 supplies or cuts off power to the electrolysis reaction zone 3 through an operating circuit switch, and controls the operating current to 1-10A. The anode catalytic electrode 331 is connected to the positive terminal of the power supply zone 4, and the cathode catalytic electrode 332 is connected to the negative terminal of the power supply zone 4.

[0036] The gas purging zone 5 is equipped with a purging gas 51 and a gas flow valve 52. The gas flow valve 52 connects the purging gas 51 to the gas inlet 335 in the electrolysis reaction zone 3. The flow rate of the purging gas is 2 to 20 mL / min, and the purging time is 1 to 5 min. Before the purging gas 51 is driven into the gas inlet 335 in the electrolysis reaction zone, the power supply to the power supply zone 4 must be cut off.

[0037] Specifically, the purge gas 51 is any one of air, oxygen, nitrogen or argon, and a gas pump can be used to supply the purge gas 51.

[0038] In this embodiment, the dimensions of both the anode catalytic electrode and the cathode catalytic electrode are 9–100 cm. 2 .

[0039] In this embodiment, the electrolyte storage tank 11 stores any one or two of the following: a strong base weak acid salt solution, a strong acid strong base salt solution, or an acidic salt solution. If it is any two solutions, their molar ratio is 1 to 5:1. The strong base weak acid salt is any one of sodium carbonate, disodium hydrogen phosphate, sodium citrate, potassium carbonate, potassium dihydrogen phosphate, or potassium citrate. The acidic salt is any one of sodium bicarbonate, calcium dihydrogen phosphate, sodium dihydrogen phosphate, potassium bicarbonate, dipotassium hydrogen phosphate, or sodium bisulfate. The strong acid strong base salt is any one of sodium chloride, sodium sulfate, potassium chloride, or potassium sulfate.

[0040] Specifically, the electrolyte concentration is 0.05–0.2 mol / L, and the pH value is controlled within the range of 7–8.5.

[0041] In this embodiment, the anode catalytic electrode 331 is any one of an iridium-tantalum electrode, a platinum electrode, a ruthenium-iridium electrode, a graphite electrode, or a titanium suboxide electrode, and the cathode catalytic electrode 332 is an electrode with two or more of the following materials loaded on its surface: carbon nanotubes, carbon black, graphite, or graphene. The distance between the anode catalytic electrode 331 and the cathode catalytic electrode 332 is 5–40 mm. The anode catalytic electrode 331 is located near the electrolyte inlet 333, and the cathode catalytic electrode 332 is located near the electrolyte outlet 334.

[0042] The cathode catalytic electrode 332 has hydrophobicity of grade 1 to 3, and the hydrophobicity of the cathode catalytic electrode 332 gradually decreases from the air-facing side to the electrolyte-facing side. The contact angle of the cathode catalytic electrode 332 on the air-facing side is 135° to 155°, and the contact angle on the electrolyte-facing side is 110° to 125°. The concentration of hydrogen peroxide solution generated by the self-breathing three-dimensional porous electrode is 15 to 1500 mg / L.

[0043] The working principle is as follows:

[0044] This embodiment can adjust the product collection system according to the hydrogen peroxide concentration requirement, and can be divided into a circulation system and an overflow system.

[0045] Circulation System: The electrolyte in the electrolyte storage tank 11 in the raw material pretreatment zone 1 is transported by the transfer pump 13 to the electrolyte inlet 333 of the membraneless electrocatalytic reactor 33 in the electrolysis reaction zone 3. Hydrogen peroxide is efficiently synthesized through the oxygen evolution reaction occurring at the anode catalytic electrode 331 and the two-electron oxygen reduction reaction occurring at the cathode catalytic electrode 332. The membraneless electrocatalytic reactor adopts the reaction principle as shown in equations (1)-(2):

[0046] Anode reaction: 2H₂O → O₂ + 4H₂O+ +4e - (1)

[0047] Cathode reaction: O2 + 2H2O + 2e - →H₂O₂ + 2OH⁻ - (2)

[0048] The electrolyte then flows out through the electrolyte outlet 334 of the membraneless electrocatalytic reactor 33 in the electrolysis reaction zone 3. The product electrolyte is circulated through the product output pipeline 338 and the circulation pipeline 337 to achieve hydrogen peroxide electrolyte circulation. Based on the real-time monitoring data of the concentration sensor 114 connected to the electrolyte storage tank 11, the system can automatically control the flow: qualified products are collected into the high-concentration finished product tank, while unqualified electrolytes are returned to the electrolysis reaction zone 3 to continue the reaction until the hydrogen peroxide product concentration reaches the standard.

[0049] The electrolyte in the electrolyte storage tank 11 of the raw material pretreatment zone 1 is transported by the transfer pump 13 to the electrolyte inlet 333 of the membrane-free electrocatalytic reactor 33 in the electrolysis reaction zone 3. Hydrogen peroxide is efficiently synthesized through the oxygen evolution reaction at the anode catalytic electrode 331 and the two-electron oxygen reduction reaction at the cathode catalytic electrode 332. The electrolyte then flows out through the electrolyte outlet 334 of the membrane-free electrocatalytic reactor 33 in the electrolysis reaction zone. The concentration of electrosynthesized hydrogen peroxide is controlled by adjusting the flow rate of the transfer pump 13 and the current in the power supply zone 4.

[0050] In addition, the flow system also needs to start the feed pump 12 to inject the electrolyte in the electrolyte raw material storage tank 14 into the electrolyte storage tank 11 in a metered manner. The flow rates of the feed pump 12 and the transfer pump 13 are kept consistent. The product electrolyte is collected into the low-concentration finished product tank via the product output line 338 and the flow line 336.

[0051] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system, characterized in that, It includes a raw material pretreatment area (1), a product collection area (2), an electrolysis reaction area (3), a power supply area (4), and a gas purging area (5); The raw material pretreatment area (1) is equipped with an electrolyte storage tank (11), a feed pump (12), a transfer pump (13), an electrolyte raw material storage tank (14), and a high-concentration product feed pump (15). The top of the electrolyte storage tank (11) is equipped with a high-concentration product inlet (111), and the side is equipped with a high-concentration product outlet (112), an electrolyte raw material inlet (113), and an electrolyte outlet (115). The high-concentration product inlet (111) is connected to the high-concentration product feed pump (15). The high-concentration product outlet (112) is connected to the second finished product tank (22) of the product collection area (2). The electrolyte raw material inlet (113) is connected to the electrolyte raw material storage tank (14) through the feed pump (12). The electrolyte outlet (115) is connected to the electrolysis reaction area (3) through the transfer pump (13). The electrolysis reaction zone (3) is equipped with a membrane-free electrocatalytic reactor (33), which includes an anode catalytic electrode (331) and a cathode catalytic electrode (332). The cathode catalytic electrode (332) is a self-breathing three-dimensional porous electrode. The anode catalytic electrode (331) and the cathode catalytic electrode (332) are respectively connected to the power supply zone (4). The membrane-free electrocatalytic reactor (33) is equipped with an electrolyte inlet (333), an electrolyte outlet (334), and a gas inlet (335). The electrolyte inlet (333) is connected to the delivery pump (13), the electrolyte outlet (334) is connected to the product output pipeline (338), the product output pipeline (338) is connected to the circulation pipeline (337) and the overflow pipeline (336) respectively, the circulation pipeline (337) is connected to the high concentration product feed pump (15), the overflow pipeline (336) is connected to the first finished product tank (21) of the product collection area (2), and the gas inlet (335) is connected to the gas purging area (5).

2. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The electrolyte storage tank (11) is connected to a concentration sensor (114), which is used to detect the concentration of hydrogen peroxide in the electrolyte storage tank (11).

3. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The flow rates of the feed pump (12) and the delivery pump (13) are 5 to 80 mL / min.

4. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The product collection area (2) is equipped with a first finished product tank (21), a second finished product tank (22), a first peristaltic pump (23) and a second peristaltic pump (24). The flow pipeline (336) is connected to the first finished product tank (21) through the first peristaltic pump (23), and the high-concentration product outlet (112) is connected to the second finished product tank (22) through the second peristaltic pump (24). The first finished product tank (21) is a low-concentration finished product tank, and the second finished product tank (22) is a high-concentration finished product tank.

5. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The membrane-free electrocatalytic reactor (33) is connected to a temperature control unit (31) and a pressure gauge (32).

6. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The anode catalytic electrode (331) is connected to the positive electrode of the power supply region (4), and the cathode catalytic electrode (332) is connected to the negative electrode of the power supply region (4).

7. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The gas purging zone (5) is equipped with an air pump and a gas flow valve (52). The air pump is used to provide purging gas (51) with a flow rate of 2 to 20 mL / min. The purging gas (51) is introduced into the gas inlet (335) through the gas flow valve (52).

8. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The anode catalytic electrode (331) is any one of an iridium-tantalum electrode, a platinum electrode, a ruthenium-iridium electrode, a graphite electrode, or a titanium suboxide electrode. The cathode catalytic electrode (332) is an electrode with two or more of the following materials loaded on its surface: carbon nanotubes, carbon black, graphite, or graphene. The distance between the anode catalytic electrode (331) and the cathode catalytic electrode (332) is 5 to 40 mm. The anode catalytic electrode (331) is located near the electrolyte inlet (333), and the cathode catalytic electrode (332) is located near the electrolyte outlet (334).

9. A self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 8, characterized in that, The cathode catalytic electrode (332) has hydrophobicity of level 1 to 3, and the hydrophobicity of the cathode catalytic electrode (332) gradually decreases from the air-facing side to the electrolyte-facing side. The contact angle of the cathode catalytic electrode (332) facing the air is 135° to 155°, and the contact angle facing the electrolyte is 110° to 125°.

10. The self-breathing, diaphragm-free hydrogen peroxide electrosynthesis system as described in claim 1, characterized in that, The electrolyte storage tank (11) stores any one or two of the following: a strong base weak acid salt solution, a strong acid strong base salt solution, or an acidic salt solution. The strong base weak acid salt is any one of sodium carbonate, disodium hydrogen phosphate, sodium citrate, potassium carbonate, potassium dihydrogen phosphate, or potassium citrate. The acidic salt is any one of sodium bicarbonate, calcium dihydrogen phosphate, sodium dihydrogen phosphate, potassium bicarbonate, dipotassium hydrogen phosphate, or sodium bisulfate. The strong acid strong base salt is any one of sodium chloride, sodium sulfate, potassium chloride, or potassium sulfate.

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