阅读说明：本技术 H2o2的连续电化学合成系统 (H2O2Continuous electrochemical synthesis system ) 是由 王玉珏 展巨宏 夏广森 赵尔卓 杨宏伟 邱向阳 余刚 于 2021-08-05 设计创作，主要内容包括：本发明提供一种H-(2)O-(2)的连续电化学合成系统,包括：由电解槽和直流电源组成的电解系统,所述电解槽内设置有阳极、气体扩散阴极,在所述气体扩散阴极的远离所述阳极一侧设置有与所述气体扩散阴极相连通的气室；所述直流电源的正、负极分别连接所述阳极与所述气体扩散阴极；供气系统,所述供气系统用于向所述气室提供气体,所述气体为空气或O-(2)；供液系统,所述供液系统用于向所述电解槽提供电解液,所述电解液为可溶性硫酸盐溶液。根据本发明实施例的H-(2)O-(2)的连续电化学合成系统,一边向气体扩散阴极连续提供气体,另一边向电解槽连续提供电解液,能够实现H-(2)O-(2)的连续化生产,且系统能够长期稳定运行。(The invention provides a method for producing H 2 O 2 The continuous electrochemical synthesis system of (a), comprising: the electrolytic system consists of an electrolytic cell and a direct current power supply, wherein an anode and a gas diffusion cathode are arranged in the electrolytic cell, and a gas chamber communicated with the gas diffusion cathode is arranged on one side of the gas diffusion cathode, which is far away from the anode; the positive electrode and the negative electrode of the direct current power supply are respectively connected with the anode and the gas diffusion cathode; an air supply system for supplying air to the air chamber, the air being air or O 2 (ii) a And the liquid supply system is used for supplying electrolyte to the electrolytic cell, and the electrolyte is soluble sulfate solution. According to the embodiment of the inventionH of (A) to (B) 2 O 2 The continuous electrochemical synthesis system can continuously provide gas to the gas diffusion cathode and electrolyte to the electrolytic cell on the other side, and H can be realized 2 O 2 The system can run stably for a long time.)

1. H₂O₂The continuous electrochemical synthesis system of (2), comprising:

the electrolysis system comprises an electrolysis bath and a direct current power supply, an anode and a gas diffusion cathode are arranged in the electrolysis bath, a gas chamber communicated with the gas diffusion cathode is arranged on one side of the gas diffusion cathode, which is far away from the anode,

the positive electrode and the negative electrode of the direct current power supply are respectively connected with the anode and the gas diffusion cathode;

an air supply system for supplying air to the air chamber, the air being air or O₂；

And the liquid supply system is used for supplying electrolyte to the electrolytic cell, the electrolyte is a solution of soluble sulfate, and the soluble sulfate is sodium sulfate, potassium sulfate or a mixture thereof.

2. The system of claim 1, further comprising:

and the automatic control system adjusts the gas supply of the gas supply system to the electrolytic cell based on the gas flow sent by the gas supply system and/or the pressure signal of the gas chamber, and adjusts the liquid supply system to supply liquid to the electrolytic cell based on the conductivity of the electrolyte in the electrolytic cell and/or the liquid flow signal of the liquid supply system.

3. The system of claim 2, further comprising:

H₂alarm device, said H₂An alarm device measures H generated by the gas diffusion cathode₂Concentration of H in the measured₂And giving an alarm when the concentration exceeds a safety threshold.

4. The system of claim 1, wherein the gas supply system comprises:

a dryer for drying the gas;

and the flowmeter is used for controlling the gas flow of the dried gas.

5. The system of claim 1, wherein the liquid supply system comprises:

the water softening equipment is used for removing alkaline earth metal ions in tap water, and is an ion exchange type water softener or a nanofiltration membrane water softener;

an electrolyte storage tank, the electrolyte storage tank comprises a water inlet, a feed inlet and a liquid outlet, the water inlet is connected with the water outlet of the water softening equipment, the feed inlet is used for adding the soluble sulfate into the electrolyte storage tank, the liquid outlet is connected with the electrolytic cell to provide the electrolyte for the electrolytic cell,

and a stirrer is arranged in the electrolyte storage tank to stir to form the electrolyte.

6. The system of claim 1, wherein the liquid supply system comprises:

the reaction tank is provided with a precipitator adding port and a liquid inlet, the liquid inlet is used for adding a sodium sulfate crude salt solution into the reaction tank, and the precipitator adding port is used for adding a precipitator into the reaction tank so as to precipitate alkaline earth metal ions in the sodium sulfate crude salt solution;

the clarifying tank is connected with the reaction tank to receive the reaction liquid from the reaction tank, and is also connected with a flocculating agent supply device to supply flocculating agent into the clarifying tank;

and the filtering device is connected with the clarifying tank to filter the liquid from the clarifying tank to obtain the solution of the soluble sulfate which is refined for the first time.

7. The system of claim 6, wherein the filtering device comprises:

a sand filter connected to the clarification tank to coarsely filter the liquid from the clarification tank to obtain a coarse filtrate;

and the alpha-cellulose filter aid precoating carbon tube filter is connected with the sand filter to carry out fine filtration on coarse filtrate from the sand filter so as to obtain the solution of the once refined soluble sulfate.

8. The system of claim 6 or 7, wherein the liquid supply system further comprises:

and the chelating resin tower is connected with the filtering device so as to carry out secondary refining on the primary refined soluble sulfate solution and obtain a secondary refined soluble sulfate solution.

9. The system of claim 1, wherein a cation exchange membrane is further disposed in the electrolysis cell between the anode and the gas diffusion cathode.

10. The system of claim 1, wherein the anode comprises Ir oxide or a metal oxide mixture of Ir and one or more metals selected from Ru, Ta, Pt, Sn, and the gas diffusion cathode supports a catalyst that is one or more of a noble metal-based catalyst or a carbon-based catalyst selected from Au-Ni-Pt, Au-Pd, Pt-Hg, Pd-Sn, Ag-Pt catalyst, and the carbon-based catalyst is one or more selected from graphite, activated carbon, carbon black, carbon nanotubes, and graphene.

Technical Field

The invention relates to the technical field of electrochemical synthesis, in particular to H₂O₂The continuous electrochemical synthesis system of (1).

Background

H₂O₂Is an important chemical product and is widely used for papermaking, spinning, chemical synthesis, environmental management, medical disinfection and the like. At present, the anthraquinone method is mainly adopted for industrial mass production of H₂O₂The method obtains H with different concentrations through the processes of hydrogenation, oxidation, extraction, purification, concentration and the like₂O₂However, the method has the disadvantages of complicated process, discontinuous production process, toxic raw materials, toxic solvent, noble metal catalyst and explosive H₂And the like, the energy consumption is high and the danger is high. In addition to the danger of the production process, H₂O₂The self-chemical property is active, the danger is very high, severe reaction can be generated when the self-chemical property is met with light, heat, organic matters, metal oxides, salts and the like, the explosion risk is caused, the strong corrosiveness is caused, the transportation risk is large, the cost is high, the transportation distance is generally not more than 300 kilometers, and H is limited₂O₂The use of (1). To reduce transportation costs, current H₂O₂The product is mainly high-concentration product (with specifications of 27.5%, 35%, 50%, 60% and 70%), the transportation risk is high, and only low-concentration H is needed in many application scenes₂O₂The operation of diluting the concentrated solution is frequently carried out. Furthermore, H concentrations higher than 8%₂O₂The solution is a strictly controlled dangerous chemical, the use and approval procedure of the solution is complicated, the storage requirement is high, the storage amount is generally small for reducing the risk, and H is also limited₂O₂The use of (1).

Electrocatalytic oxygen (O)₂) The reduction reaction can be carried out by one-step electrochemical reaction₂And H₂Conversion of O to H₂O₂Is a simple and clean H₂O₂The synthesis method is expected to replace the multi-step anthraquinone method with complicated process at present, and is easy to realize H₂O₂Continuous production and in-situ production in specific application scenarios, H reduction₂O₂High costs and potential risks during production, transport, storage, use.

However, at present, no electrochemical synthesis of H is available₂O₂The continuous production equipment.

Disclosure of Invention

In view of the above, the present invention provides a method for producing H₂O₂Continuous electrochemical synthesis system of (1), realizing H₂O₂Continuous production and long-term stable operation of the system.

In order to solve the technical problems, the invention adopts the following technical scheme:

h according to an embodiment of the present invention₂O₂The continuous electrochemical synthesis system of (a), comprising:

an electrolysis system, which comprises an electrolysis bath and a direct current power supply,

an anode and a gas diffusion cathode are arranged in the electrolytic cell, and a gas chamber communicated with the gas diffusion cathode is arranged on one side of the gas diffusion cathode, which is far away from the anode;

the positive electrode and the negative electrode of the direct current power supply are respectively connected with the anode and the gas diffusion cathode;

a gas supply system for supplying gas to the gas diffusion cathode, the gas being air or O₂；

And the liquid supply system is used for supplying electrolyte to the electrolytic cell, the electrolyte is a solution of soluble sulfate, and the soluble sulfate is sodium sulfate, potassium sulfate or a mixture thereof.

Further, the system further comprises:

and the automatic control system adjusts the gas supply of the gas supply system to the electrolytic cell based on the gas flow sent by the gas supply system and/or the pressure signal of the gas chamber, and adjusts the liquid supply system to supply liquid to the electrolytic cell based on the conductivity of the electrolyte in the electrolytic cell and/or the liquid flow signal of the liquid supply system.

Further, the system further comprises:

H₂alarm device, said H₂An alarm device measures H generated by the gas diffusion cathode₂Concentration of H in the measured₂Alarm is given when the concentration exceeds a safety threshold

That is, through H₂Alarm device for measuring H near electrolytic tank₂Concentration, H after reaching the alarm concentration (i.e. safety threshold)₂The alarm device gives an alarm, and according to the alarm signal, the automatic control system can control the electrolysis system to stop running, and manually cut off the power to replace the gas diffusion cathode. Wherein the safety threshold value can be determined, for example, according to the volume of the enclosed space where the electrolytic cell is located and H₂10% of the lower limit of the explosion limit range is calculated and set.

Further, the system further comprises:

H₂O₂storage tank, said H₂O₂A storage tank connected to the electrolytic cell for receiving H produced by the electrolytic cell₂O₂。

Further, the gas supply system includes:

a dryer for drying the gas;

and the flowmeter is used for controlling the gas flow of the dried gas.

According to some embodiments of the invention, the liquid supply system comprises:

the water softening equipment is used for removing alkaline earth metal ions in tap water, and is an ion exchange type water softener or a nanofiltration membrane water softener;

an electrolyte storage tank, the electrolyte storage tank comprises a water inlet, a feed inlet and a liquid outlet, the water inlet is connected with the water outlet of the water softening equipment, the feed inlet is used for adding the soluble sulfate into the electrolyte storage tank, the liquid outlet is connected with the electrolytic cell to provide the electrolyte for the electrolytic cell,

and a stirrer is arranged in the electrolyte storage tank to stir to form the electrolyte.

According to the requirements of national standards of drinking water and the technical sodium sulfate, ions of other alkaline earth metals such as beryllium, strontium, barium and radium in tap water and industrial sodium sulfate have low content and cannot generate large influence on electrolysis, however, the existence of calcium ions and magnesium ions can generate precipitation in the electrolysis process, so that adverse effect is generated on an electrolysis system, and therefore, the electrolysis efficiency can be effectively improved by removing the magnesium ions and the calcium ions in the tap water through the water softening equipment.

According to further embodiments of the invention, the liquid supply system comprises:

the reaction tank is provided with a precipitator adding port and a liquid inlet, the liquid inlet is used for adding a soluble sulfate crude salt solution into the reaction tank, and the precipitator adding port is used for adding a precipitator into the reaction tank so as to precipitate alkaline earth metal ions in the soluble sulfate crude salt solution;

the clarifying tank is connected with the reaction tank to receive the reaction liquid from the reaction tank, and is also connected with a flocculating agent supply device to supply flocculating agent into the clarifying tank;

and the filtering device is connected with the clarifying tank to filter the liquid from the clarifying tank to obtain the primary refined soluble sulfate solution.

The soluble sulfate may be, for example, sodium sulfate, potassium sulfate, or a mixture thereof.

The alkaline earth metal ion impurities may be, for example, calcium ions, magnesium ions, or a mixture thereof.

Further, the filtering apparatus includes:

a sand filter connected to the clarification tank to coarsely filter the liquid from the clarification tank to obtain a coarse filtrate;

and the alpha-cellulose filter aid precoating carbon tube filter is connected with the sand filter to carry out fine filtration on coarse filtrate from the sand filter so as to obtain the primary refined soluble sulfate solution.

Still further, the liquid supply system further comprises:

and the chelating resin tower is connected with the filtering device so as to carry out secondary refining on the solution of the soluble sulfate which is refined for the first time, and obtain the solution of the soluble sulfate which is refined for the second time.

According to further embodiments of the invention, a cation exchange membrane is further provided in the electrolytic cell between the anode and the gas diffusion cathode.

The cation exchange membrane is a selectively permeable membrane that allows only cations to permeate.

H formed at cathode₂O₂Is easy to diffuse or migrate to the anode for oxidative decomposition, and high concentration H cannot be obtained₂O₂. To avoid H₂O₂Oxidizing and obtaining high concentration of H₂O₂The electrolytic cell is divided into an anode chamber and a cathode chamber by adding a cation exchange membrane between the cathode and the anode, because of H₂O₂In water in the form of H₂O₂Molecule andions, while cation exchange membranes allow only cations to permeate, so H₂O₂Molecule andions are all retained in the cathode chamber, whereby a high concentration of H can be obtained₂O₂. The commercially available cation exchange membranes are various in types and can avoid H₂O₂Molecule andions migrate to and are oxidized by the anode to obtain a high concentration of H₂O₂。

Cation exchange membranes are optional components in electrolytic cells at low concentrations of H₂O₂Application scenarios (less than 1000mg/L), H₂O₂The anodic oxidation is not obvious, and a cation exchange membrane can be omitted.

Further, the anode contains Ir oxide or a metal oxide mixture of Ir and one or more metals selected from Ru, Ta, Pt and Sn, the gas diffusion cathode is loaded with a catalyst, the catalyst is a noble metal catalyst or a carbon-based catalyst, the noble metal catalyst is one or more catalysts selected from Au-Ni-Pt, Au-Pd, Pt-Hg, Pd-Sn and Ag-Pt, and the carbon-based catalyst is one or more catalysts selected from graphite, activated carbon, carbon black, carbon nanotubes and graphene.

The technical scheme of the invention at least has one of the following beneficial effects:

h according to an embodiment of the present invention₂O₂The continuous electrochemical synthesis system can continuously provide gas to the gas diffusion cathode and electrolyte to the electrolytic cell on the other side, and H can be realized₂O₂The system can run stably for a long time;

further, by adjusting the current of the DC power supply, the generated H can be adjusted₂O₂Has a reduced H content as compared with the anthraquinone process₂O₂Diluting a concentrated solution;

further, through automatic control system, based on gas flow that gas supply system sent and/or the pressure signal of air chamber adjusts gas supply system to the air feed of electrolysis trough, both avoided oxygen supply volume or oxygen supply pressure not enough to lead to the negative pole gas diffusion passageway to be flooded by electrolyte, avoided using too high oxygen supply volume again and oxygen supply pressure to cause waste and running cost's improvement, just automatic control system based on in the electrolysis trough the conductivity of electrolyte and/or liquid flow signal of liquid supply system adjusts the liquid supply system to the electrolysis troughLiquid supply, can continuously and stably generate electrochemical synthesis reaction at the gas diffusion cathode to obtain H₂O₂；

Further, by H₂Alarm device detects H₂Concentration, which can effectively prevent H generation stop caused by filling or flooding of gas diffusion channels of the cathode with electrolyte (electrode wetting)₂O₂The risk of explosion caused by hydrogen evolution reaction begins to occur;

further, a saturated sodium sulfate electrolyte was prepared by an electrolyte refining system and the electrolyte Ca was removed²⁺、Mg²⁺And impurities are avoided, so that the scaling of the cathode and the damage to the ion exchange membrane are avoided.

Drawings

FIG. 1 is a drawing H of an embodiment of the present invention₂O₂Schematic diagram of a continuous electrochemical synthesis system of (a);

FIG. 2 is a schematic view of an air supply system according to an embodiment of the present invention;

FIG. 3 is a schematic view of a liquid supply system in an embodiment of the invention;

FIG. 4 is a schematic view of a liquid supply system in another embodiment of the invention;

FIG. 5 is a schematic view of an electrolytic cell in an embodiment of the present invention;

FIG. 6 is a schematic view of an electrolytic cell according to another embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.

First, a detailed description of H according to an embodiment of the present invention will be given with reference to the accompanying drawings₂O₂The continuous electrochemical synthesis system of (1).

As shown in fig. 1, H according to an embodiment of the present invention₂O₂The continuous electrochemical synthesis system comprises an electrolysis system 1, a gas supply system 300 and a liquid supply system 400.

The electrolysis system 1 includes an electrolysis cell 100 and a DC power supply 200.

As shown in fig. 5 to 6, a gas diffusion cathode 110 and an anode 120 are provided in the electrolytic cell 100, and a gas chamber 130 communicating with the gas diffusion cathode 110 is provided on the side of the gas diffusion cathode 110 remote from the anode 120. The electrolytic cell 100 is for containing an electrolyte.

The positive and negative poles of the dc power supply 200 are connected to the anode 120 and the gas diffusion cathode 110 in the electrolytic cell, respectively.

The gas supply system 300 is used to supply gas, such as air or O, to the plenum 130₂. Since the gas chamber 130 is in communication with the gas diffusion cathode 110, that is, the gas is supplied to the gas diffusion cathode 110 through the gas chamber 130 to generate O at the gas diffusion cathode₂And H₂Electrochemical synthesis reaction of O to H₂O₂。

The liquid supply system 400 is used to provide an electrolyte, such as a soluble sulfate solution, to the cell 100.

An electrolysis process:

(1) the positive pole of the DC power supply 200 is connected with the anode of the electrolytic cell 100The electrode 120 and the negative electrode of the DC power supply 200 are connected with the cathode of the electrolytic cell 100, namely the gas diffusion cathode 110, and the electrolysis is carried out in a constant current mode with the working current density of 20-300mA/cm²And the output H can be adjusted by adjusting the current in the electrolytic process₂O₂Concentration (typically between 0.1% and 30%).

(2) Gas management: the key to the long term stable operation of the electrolysis process is gas management of the gas chamber and the gas diffusion cathode. Generally, the current density is 20-300mA/cm²When the pressure and oxygen supply of the gas chamber 130 are respectively 5-100kPa O₂Or 20-500kPa air, 10-150mL/min O₂Or 50-750mL/min air.

H according to an embodiment of the present invention₂O₂The continuous electrochemical synthesis system of (1) continuously supplying gas to the gas diffusion cathode 110 and continuously supplying electrolyte to the electrolytic cell 100 on the other side, can realize H₂O₂The system can run stably for a long time. Further, H according to an embodiment of the present invention₂O₂The continuous electrochemical synthesis system can synthesize H with different concentrations by simply adjusting the power supply current of the direct current power supply₂O₂Satisfy various application scene pairs H₂O₂Need of (1), reduction of H₂O₂And (5) diluting the concentrated solution.

Further, the system may also include an automated control system 500. The automatic control system 500 adjusts the gas supply of the gas supply system 300 to the electrolytic cell based on the gas flow rate emitted by the gas supply system 300 and/or the pressure signal of the gas chamber 130, and the automatic control system 500 adjusts the liquid supply of the liquid supply system 400 to the electrolytic cell 100 based on the conductivity of the electrolyte in the electrolytic cell 100 and/or the liquid flow rate signal of the liquid supply system 400.

Thus, by adjusting the gas supply system 300 to supply gas to the electrolytic cell 100 based on the gas flow rate from the gas supply system 300 and/or the pressure signal from the gas chamber 130 through the automated control system 500, not only is the gas diffusion channel of the cathode prevented from being submerged by the electrolyte due to insufficient oxygen supply or insufficient oxygen supply pressure, but also waste and increased operating costs due to the use of excessive oxygen supply and oxygen supply pressure can be avoided.

Specifically, according to the magnitude of the working current density, the oxygen supply amount and the working pressure of the gas chamber suitable for the current density are automatically matched. When the electrolytic cell is operated at any current density, the electrolytic cell has better working pressure and oxygen supply quantity of the gas chamber for long-term stable operation, and the built-in current density of the automatic control system is 20-300mA/cm²The optimal air chamber pressure and oxygen supply amount corresponding to each current density in the range realize optimal gas management on the basis, thereby avoiding that the cathode gas diffusion channel is submerged by electrolyte due to insufficient oxygen supply amount or oxygen supply pressure, and avoiding waste and improvement of operation cost caused by overhigh oxygen supply amount and oxygen supply pressure.

In addition, the automatic control system 500 adjusts the liquid supply system 400 to supply liquid to the electrolytic cell based on the conductivity of the electrolyte in the electrolytic cell 100 and/or the liquid flow signal of the liquid supply system 400, and can control the conductivity of the electrolyte to a certain level, so that the electrochemical synthesis reaction can be continuously and stably generated at the gas diffusion cathode to obtain H₂O₂。

Further, the system may further include H₂An alarm device 600. H₂Alarm device 600 measures H generated in the vicinity of gas diffusion cathode 110₂In accordance with the H₂The concentration and the volume of the enclosed space in which the cell 100 is located, an alarm is generated. According to the volume of the closed space where the electrolytic cell is located and H₂Calculating 10% of lower limit value of explosion limit range, setting alarm concentration, and after the alarm concentration is reached, H₂The alarm device gives an alarm. For example, an alarm sound is given, and a warning message for replacing the gas diffusion cathode 110 is given. Based on the alarm signal, the automatic control system can be controlled to stop the operation of the electrolysis system, manually cut off the power to replace the gas diffusion cathode, and the like.

By H₂Alarm device 600 detects H₂Concentration, which can effectively prevent H generation stop caused by filling or flooding of gas diffusion channels of the cathode with electrolyte (electrode wetting)₂O₂And the risk of explosion of the hydrogen evolution reaction begins to occur.

In addition, the synthesis system may further include:

H₂O₂storage tank, said H₂O₂A storage tank connected to the electrolytic cell for receiving H produced by the electrolytic cell₂O₂。

The electrolytic cell 100, the DC power supply 200, the gas supply system 300, and the liquid supply system 400 will be described in further detail with reference to FIGS. 2 to 6.

First, the air supply system 300 is described in conjunction with fig. 2.

As shown in fig. 2, the air supply system 300 of the present invention includes a dryer 310 and a flow meter 320.

The dryer 310 is used to dry the gas, and the dried gas is supplied to the gas chamber 130 through the flow meter 320. The dryer 310 is an optional component, and air may enter the air chamber of the electrolyzer 100 directly without passing through the dryer during seasons and regions where the relative humidity of the air is less than 30%.

The function of the gas supply system is as follows: providing electric synthesis H₂O₂The desired reactant O₂(ii) a Maintaining a certain pressure in the air chamber; and thirdly, the gas supplied to the gas chamber 130 in the electrolytic bath 100 is dried, so that the water accumulation of the gas chamber caused by high air humidity is avoided.

As an example, the air supply system may adopt several structures as follows:

the air supply system is as follows: as shown in fig. 2, a fan 330 is included in addition to the dryer 310 and the flow meter 320.

The process flow of the gas supply system is as follows: air is delivered to the dryer 310 by the blower 330 to obtain dry air; the dry air is then introduced into the air chamber 130 of the electrolytic cell 100 at a flow rate and pressure through the flow meter 320.

The blower 330 can be selected according to the pressure required by the air chamber in the actual operation process of the electrolytic cell 100, generally, the pressure of the air chamber is lower than 15kPa, and the blower can be used for supplying oxygen; the pressure of the air chamber is 15-200kPa, and a blower can be used for supplying oxygen; the pressure of the air chamber is higher than 200kPa, and oxygen can be supplied by a compressor.

The dryer 310 can be a tube type, and the interior of the dryer is filled with allochroic silicagel which can be heated and regenerated for recycling.

And a second gas supply system: comprises a dryer 310, a molecular sieve oxygenerator and a flow meter 320.

And a second process flow of the gas supply system: the air enters the molecular sieve oxygen generator after being dried by the dryer 310, the oxygen concentration of the generated gas is more than or equal to 90 percent, and the generated gas of the oxygen generator is introduced into the air chamber 130 of the electrolytic cell 100 at a certain flow rate and pressure through the flow meter 320.

The dryer 310 is a tube type and is connected with the air inlet of the molecular sieve oxygen generator, and the interior of the dryer is filled with allochroic silica gel which can be heated and regenerated for recycling.

And a third gas supply system: including air or O₂Cylinder, pressure reducing valve, flow meter 320.

The gas supply system comprises three process flows: air or O in cylinders₂After being decompressed by the decompression valve, the gas is introduced into the gas chamber of the electrolytic cell 100 through the flow meter 320 at a certain flow rate and pressure, and the pressure and the flow rate are respectively adjusted by the decompression valve and the flow meter 320.

Wherein oxygen-enriched gas (oxygen content is more than or equal to 90%) or O generated by oxygen generator is adopted₂The steel cylinder is used as O₂When the source is used in electrolytic reactions, O₂The flow rate and the working pressure of the air chamber can be operated according to the oxygen supply amount of the air source and the air pressure of 20-30%.

The liquid supply system 400 is described in further detail below in conjunction with FIGS. 3-4.

The liquid supply system 400 is mainly used for preparing electrolyte for electrolysis process and removing alkaline earth metal ions such as Ca from the electrolyte²⁺、Mg²⁺And impurities are avoided, so that the scaling of the cathode and the damage to the cation exchange membrane are avoided, and the service life of the cation exchange membrane and the service life of the gas diffusion cathode are prolonged.

Wherein, analytical pure, high-grade pure sodium sulfate or industrial sodium sulfate high-grade products are adopted as electrolytes, tap water is used for preparing the electrolytes, and industrial sodium sulfate with high impurity content can also be used as the electrolytes, and the tap water is used for preparing the electrolytes.

The liquid supply system 400 shown in fig. 3 may be used when preparing an electrolyte from tap water using analytically pure, sodium sulfate or sodium sulfate industrial grade products as electrolytes.

As shown in FIG. 3, the liquid supply system 400 includes a water softener and an electrolyte reservoir.

Wherein the water softening plant is used for removing alkaline earth metal ions such as Ca from tap water²⁺、Mg²⁺. For example, the water softening apparatus may be an ion exchange type water softener, a nanofiltration membrane water softener, or the like.

Electrolyte reserve tank includes water inlet and charge door and liquid outlet, the water inlet links to each other in order to receive the demineralized water that comes from water softening equipment through softening treatment with water softening equipment's delivery port, the feed inlet be used for to add the soluble sulfate as the electrolyte in the electrolyte reserve tank, sodium sulfate, potassium sulfate or its mixture for example, electrolysis trough 100 is connected in order to provide to electrolysis trough 100 to electrolyte, be equipped with the mixer in the electrolyte reserve tank and form with the stirring electrolyte.

Further, the electrolyte storage tank may be used for preparing and storing the concentrated electrolyte, and the liquid supply system 400 may further include a pipeline mixer, the pipeline mixer connects the water softening equipment and the electrolyte storage tank, and the concentrated electrolyte is mixed and diluted by the pipeline mixer to obtain a diluted electrolyte with a predetermined concentration for being supplied to the electrolytic cell 100.

The liquid supply system 400 shown in fig. 4 may be used when the electrolyte is prepared from tap water with industrial sodium sulfate having a high impurity content as the electrolyte.

As shown in FIG. 4, the liquid supply system 400 includes: a reaction tank, a clarifying tank and a filtering device.

Wherein the reaction tank is provided with a precipitator adding port and a liquid inlet, the liquid inlet is used for adding sodium sulfate crude salt solution such as industrial sodium sulfate aqueous solution into the reaction tank, and the precipitator adding port is used for adding a precipitator such as sodium hydroxide, sodium carbonate and the like into the reaction tank so as to precipitate alkaline earth metal ions such as Ca in the sodium sulfate crude salt solution²⁺、Mg²⁺Or mixtures thereof.

The clarifying tank is connected with the reaction tank to receive the reaction liquid from the reaction tank, and is also connected with a flocculating agent supply device to supply a flocculating agent such as sodium polyacrylate into the clarifying tank.

And the filtering device is connected with the clarifying tank to filter the liquid from the clarifying tank to obtain the primary refined soluble sulfate solution.

That is, first, a precipitant such as sodium carbonate or sodium hydroxide is used to perform a substitution reaction with alkaline earth metal ions such as calcium ions or magnesium ions in an industrial sodium sulfate aqueous solution to precipitate the alkaline earth metal ions; then, the fine particles are flocculated by passing through a clarifying tank, and finally, the fine precipitate particles remained in the clarifying tank are further filtered by a filtering device. Thereby avoiding cathode scaling and damage to the ion exchange membrane.

Further, as shown in fig. 4, the filtering apparatus may include:

a sand filter connected to the clarification tank to coarsely filter the liquid from the clarification tank to obtain a coarse filtrate;

and the alpha-cellulose filter aid precoating carbon tube filter is connected with the sand filter to carry out fine filtration on coarse filtrate from the sand filter so as to obtain the once refined soluble sulfate solution.

Thus, the precipitate particles of different sizes can be further removed by fractional filtration to obtain a primary purified soluble sulfate solution.

Further, as shown in fig. 4, the liquid supply system may further include: and (4) a chelating resin tower. And the chelating resin tower is connected with the filtering device to carry out secondary refining on the primary refined soluble sulfate solution to obtain a secondary refined soluble sulfate solution. The secondary salt refining principle is ion exchange method, ion exchange resin and Na in chelating resin tower⁺Weak binding force with alkaline earth metal ions such as Ca²⁺、Mg²⁺Strong binding force when containing Ca²⁺、Mg²⁺After entering the chelating resin tower, unstable Na is combined with resin⁺Quilt Ca²⁺、Mg²⁺Substitution, thereby removing Ca²⁺、Mg²⁺。

The above primary and secondary refining can remove impurities such as calcium ions and magnesium ions in the alkaline earth metal ions in the electrolyte solution, i.e., the soluble sulfate solution, to a great extent.

The electrolytic cell 100 is described in detail below with reference to fig. 5 to 6.

According to some embodiments of the invention, as shown in fig. 5, an ion-free membrane electrolyzer is used. The non-ionic membrane electrode tank has simple structure and is mainly suitable for producing low-concentration H₂O₂(1000mg/L or less).

As shown in FIG. 5, a gas diffusion cathode 110, an anode 120 and a gas chamber 130 are arranged in the electrolytic cell 100, wherein the gas chamber 130 is arranged at the side of the gas diffusion cathode far away from the anode and is communicated with the gas diffusion cathode 110.

In which the cathode, i.e. the gas diffusion cathode 110, is electrocatalyzed₂Reduction of H₂O₂Reaction of (2), O in the gas cell 130₂The gas diffusion cathode 110 reaches the interface with the electrolyte to react, and the gas diffusion cathode 110 is connected with the gas chamber plate frame through gluing or fastening bolts/nuts to form a sealed gas chamber 130.

The gas chamber 130 may be equipped with a gas diffusion cathode 110 on one side (as shown in fig. 5) or on both sides (not shown), as desired. When the gas diffusion cathode 110 is assembled on one side, the other side is replaced with a plate (which may be a metal plate, a plexiglass plate, etc.) having the same size as the gas diffusion cathode 110 to seal the gas chamber.

Further, the anode 120 is an oxygen evolution anode, and the active component is an oxide of a noble metal Ir or a metal oxide mixture of Ir and other metal elements, such as Ru, Ta, Pt, Sn, and the like.

The active component of the gas diffusion cathode 110 can be a noble metal catalyst (e.g., Au-Ni-Pt, Au-Pd, Pt-Hg, Pd-Sn, Ag-Pt, etc.), a carbon-based catalyst (e.g., graphite, activated carbon, carbon black, carbon nanotube, or graphene, etc.), and the carbon-based catalyst can be modified by oxidation, heteroatom doping, etc. to improve the electrocatalytic O₂Reduction of H₂O₂Selectivity of (ii).

According to other embodiments of the present invention, as shown in FIG. 6, an ion membrane electrolyzer may also be used.

In the ion membrane electrolyzer, as shown in fig. 6, a cation exchange membrane 140 is further provided between the anode 120 and the gas diffusion cathode 110. That is, the electrolytic cell 100 is partitioned into an anode chamber and a cathode chamber by the cation exchange membrane 140, and the other side of the cathode chamber is the gas chamber. During the electrolysis, the pressure of the cathode chamber can be maintained to be 5-10kPa higher than that of the anode chamber.

Similarly, gas cell 130 can be equipped with gas diffusion cathode 110 on one side (as shown in FIG. 6) or on both sides (not shown), and when the gas diffusion cathode is equipped on one side, the gas cell is sealed instead with a sheet material (which can be a metal sheet, a plexiglass sheet, etc.) of the same size as the gas diffusion cathode on the other side.

Next, the above-mentioned H is combined₂O₂Continuous electrochemical Synthesis System of (1), Explanation H₂O₂The continuous electrochemical synthesis method of (1).

Using the above-mentioned H₂O₂Continuous electrochemical synthesis system of (1) to carry out H₂O₂The continuous electrochemical synthesis method comprises the following steps:

step S1, supplying direct current to an electrolytic cell by a direct current power supply, wherein the electrolytic cell is filled with electrolyte and is provided with an anode, a gas diffusion cathode and a gas chamber communicated with the gas diffusion cathode;

step S2, gas is supplied to the gas chamber of the electrolytic cell through a gas supply system, and the electrolyte is continuously supplied to the electrolytic cell through a liquid supply system, so that the gas and the electrolyte generate electrolytic reaction on the surface of the gas diffusion cathode to obtain H₂O₂。

That is, H can be achieved by continuously supplying gas to the gas diffusion cathode 110 and electrolyte to the electrolytic cell 100₂O₂The system can run stably for a long time.

According to the method, the H with different concentrations can be synthesized by simply adjusting the magnitude of the power supply current of the direct current power supply₂O₂Satisfy all kinds of responsesBy scene pair H₂O₂Need of (1), reduction of H₂O₂And (5) diluting the concentrated solution.

Further, the synthesis method may further include:

step S3, adjusting the gas supply system according to the gas pressure of the gas chamber and/or the gas flow of the gas;

and step S4, adjusting the liquid supply system to supply the electrolyte to the electrolytic cell according to the conductivity of the electrolyte in the electrolytic cell and/or the liquid flow signal of the liquid supply system.

That is, in step S3, the gas supply system 300 is adjusted to supply gas to the electrolytic cell 100 based on the gas flow rate from the gas supply system 300 and/or the pressure signal from the gas chamber 130, so as to avoid the gas diffusion channel of the cathode from being submerged by the electrolyte due to insufficient oxygen supply or oxygen supply pressure, and to avoid waste and increase in running cost due to excessive oxygen supply and oxygen supply pressure.

In addition, in step S4, the liquid supply system 400 is adjusted to supply liquid to the electrolytic cell based on the conductivity of the electrolyte in the electrolytic cell 100 and/or the liquid flow rate signal of the liquid supply system 400, so that the conductivity of the electrolyte can be controlled to a certain level, and the electrochemical synthesis reaction can be continuously and stably generated at the gas diffusion cathode to obtain H₂O₂。

Further, the synthesis method may further include:

step S5, measuring H generated by the gas diffusion cathode₂In accordance with the H₂The concentration and the volume of the enclosed space in which the electrolytic cell is located give an alarm.

That is, through H₂Alarm device 600 detects H₂Concentration, which can effectively prevent H generation stop caused by filling or flooding of gas diffusion channels of the cathode with electrolyte (electrode wetting)₂O₂And the risk of explosion of the hydrogen evolution reaction begins to occur.

Specifically, for example, H₂Alarm device 600 detects H near the electrolytic cell₂Concentration exceeding a predetermined safety value (e.g. depending on the enclosed space in which the cell is located)Volume sum H₂The value calculated by 10 percent of the lower limit value of the explosion limit range) is an alarm, and a signal is transmitted to an automatic control system to automatically close the direct current power supply and stop electrolysis.

In step S1, the DC power supply is, for example, a constant current power supply, and the current density is 20-300mA/cm²。

Further, step S2 may include:

and step S21, drying the gas, and supplying the dried gas to the gas chamber.

That is, the gas is dried and supplied to the gas chamber.

The gas is air or O₂The gas flow rate is 50-750mL/min in the case of air, O₂Under the condition of (2), the concentration is 10-150 mL/min. And in the electrolytic process, the working pressure of the air chamber can be 20-500kPa under the condition of air and O₂In the case of (B), 5 to 100 kPa. By continuously and stably supplying O required for electrolytic reaction₂(air) capable of continuously and stably performing an electrolytic reaction to obtain H₂O₂。

Under the condition of using the ion membrane electrolytic cell, the pressure of the cathode chamber can be controlled and maintained to be higher than the pressure of the anode chamber by 5-10kPa during the electrolysis process, so that the cation exchange membrane is tightly attached to the anode, and the membrane vibration and damage caused by frequent changes of the pressures of the cathode chamber and the anode chamber are reduced.

The gas supply conditions can ensure that the gas diffusion cathode can stably generate H for a long time₂O₂The pressure difference between the cathode chamber and the cathode chamber can obviously prolong the service life of the membrane.

In step S21, the dried O₂Or the relative humidity of the air is 30% or less. That is, when the relative humidity of the atmosphere is 30% or less, the atmosphere can be directly supplied to the gas chamber of the electrolytic cell without being dried.

Step S22, supplying a refined electrolyte solution through an electrolyte solution refining system, and supplying the refined electrolyte solution to the electrolytic cell.

That is, the electrolytic solution needs to be refined to remove impurities therein and then supplied to the electrolytic bath.

Specifically, step S22 may include:

mixing softened water with purified sodium sulfate to obtain a refined soluble sulfate solution;

providing the refined soluble sulfate solution to the electrolytic cell.

That is, when purified sodium sulfate is reused, it can be directly dissolved in demineralized water to form an electrolyte solution of a desired concentration, and the electrolyte solution can be supplied to the electrolytic cell. Of course, the softened water may be commercially available softened water, or tap water may be passed through a water softening plant to remove alkaline earth metal ions such as Ca therefrom²⁺、Mg²⁺And preparing softened water after impurities are waited.

In addition, the electrolyte can also be prepared using crude sodium sulfate salt with tap water.

At this time, step S22 includes:

stirring the crude sodium sulfate salt with tap water to obtain a saturated crude sodium sulfate salt aqueous solution;

adding sodium carbonate and/or sodium hydroxide into the saturated crude sodium sulfate salt water solution to enable alkaline earth metal ions Ca in the saturated crude sodium sulfate salt water solution to be in a Ca state²⁺、Mg²⁺Precipitating a generated precipitate to obtain a reaction solution;

adding a flocculating agent into the reaction solution, and carrying out rough filtration through a quartz sand filter to obtain a rough filtrate;

and filtering the crude filtrate by using an alpha-cellulose filter aid precoated carbon tube filter to obtain a primary refined soluble sulfate solution.

That is, the fine precipitate particles are flocculated by adding a flocculant, and finally, primary purification is performed by rough filtration and fine filtration using a filter.

Further, after the primary purification, the secondary purification may be carried out by utilizing the ion exchange principle in order to further remove a small amount of alkaline earth metal ions such as calcium and magnesium ions remaining therein. Specifically, the method comprises the following steps:

introducing the primary refined soluble sulfate solution into a chelating resin tower for exchange to obtain a secondary refined soluble sulfate solution;

and mixing the secondary refined soluble sulfate solution with softened water to obtain the refined soluble sulfate solution with the preset concentration.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.