Water treatment device for electrolytic hydrogen production of effluent of sewage plant

Abstract

The invention discloses a water treatment device for electrolytic hydrogen production of effluent from a sewage plant, the water treatment device comprises a device main body, a filter assembly and a sedimentation mechanism, the device main body comprises a shell, a partition plate and a pump body, the partition plate is fixed in the shell so as to divide an inner cavity of the shell into an upper accommodating cavity and a lower accommodating cavity, and the upper accommodating cavity is communicated with the lower accommodating cavity; a first mounting hole is formed in the partition plate, and a first control valve is arranged in the first mounting hole; and the settling mechanism is arranged in the lower accommodating cavity. The method has the beneficial effects that the alkaline electrolyte is mixed with the tail water in advance under the alkaline condition in the alkaline electrolysis process, metal cations in the tail water are promoted to be precipitated in advance and removed through membrane filtration, and then the mixed solution is introduced into the electrolytic bath, so that impurities are efficiently and economically removed, an expensive reverse osmosis device is not needed, and the method is simple and convenient to operate. And moreover, the generation amount of precipitates in the electrolytic bath is reduced, and the catalytic activity and stability of the electrode are improved.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment devices, and in particular to a water treatment device used for electrolyzing effluent from a sewage plant to produce hydrogen. Background Art

[0002] As a clean and efficient energy carrier, hydrogen energy is a key component of my country's energy system and a core direction for the development of strategic emerging industries. At present, more than 90% of hydrogen comes from fossil energy such as coal and natural gas. Its high energy consumption and high carbon emissions limit its widespread application in low-carbon fields. In contrast, green hydrogen can achieve true zero-carbon hydrogen production through electrolysis or photocatalytic water decomposition through fluctuating renewable energy such as wind and solar energy.

[0003] However, the process of producing hydrogen by electrolysis of water requires a lot of energy and high-quality water sources. In areas rich in clean energy, high-quality water sources are often scarce, resulting in a contradiction between "energy and water resources". It is worth noting that low-grade water (such as seawater, surface water, groundwater, and sewage treatment plant effluent, etc.) accounts for 97% of the world's water resources. If low-grade water can be directly used for electrolysis to produce hydrogen, it can not only avoid the large amount of pure water consumption in the traditional electrolysis hydrogen production process, but also save the construction of water purification facilities, thereby greatly reducing the infrastructure investment and operation and maintenance costs related to water treatment, thereby solving the fundamental contradiction between "energy and water resources" and realizing hydrogen production in the whole region.

[0004] Seawater is not advantageous due to its high salinity, which is 10 to 30 times that of other water sources. Although the quality of surface water and groundwater is similar to that of tailwater from sewage treatment plants, the water quality fluctuates greatly due to geological changes and seasonal factors, and these water sources give priority to meeting the water needs of municipal residents, agriculture and industry. In contrast, tailwater from sewage treatment plants has the advantages of stable water quality and quantity, making it an ideal choice for hydrogen production from low-grade water. More importantly, the pure oxygen produced during the electrolysis of water can be used as a high-quality oxygen source for the biological treatment process of sewage treatment plants, which helps to improve aeration efficiency and reduce energy consumption. At the same time, sewage treatment plants usually have a large footprint and less obstructed building conditions, which are suitable for installing photovoltaic systems to provide efficient energy supply for electrolysis equipment.

[0005] In the water electrolysis hydrogen production system, raw water enters the electrolysis cycle after adding electrolyte. As hydrogen and oxygen are generated, the electrolyte gradually concentrates. When the liquid level reaches a predetermined level, raw water needs to be replenished to maintain the normal operation of the system, and the concentration of the electrolyte will gradually accumulate trace impurity factors in the water. During the electrolysis process, the cathode produces a large amount of OH due to the hydrogen evolution reaction. - , causing the pH near the cathode to rise locally, and the rich Ca in the tail water 2+ Mg 2+ Will induce Mg(OH) 2 and Ca(OH)2 The precipitate is deposited and attached to the surface of the cathode catalyst, which hinders the exposure of active sites and thus reduces the catalytic activity and stability of the electrode. 2+ , Cu 2+ It may trigger the Fenton reaction to produce hydroxyl radicals to attack the diaphragm and electrode catalyst materials, thereby damaging the diaphragm and catalyst layer.

[0006] At present, the deep treatment of sewage plant effluent into electrolyte mainly uses reverse osmosis technology, but due to its high investment and operating costs, as well as membrane pollution problems, it is difficult to be widely used in industry; another technology is ion adsorption, but high concentrations of OH - Affect its use and even quickly adsorb and saturate.

[0007] In traditional alkaline electrolysis, since the electrolyte is usually a high concentration of KOH, the tail water tends to precipitate quickly when it comes into contact with the electrolyte; at the same time, the circulation process causes the electrolyte to concentrate, which can also cause precipitation. This type of precipitation hinders the exposure of active sites, thereby reducing the catalytic activity and stability of the electrode. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and propose a water treatment device for electrolyzing hydrogen from sewage plant effluent, so as to solve the technical problem in the prior art that when tail water comes into contact with electrolyte, precipitation is easily and quickly generated, which hinders the exposure of active sites and thus reduces the catalytic activity and stability of the electrode.

[0009] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The present invention provides a water treatment device for producing hydrogen by electrolyzing effluent from a sewage plant, comprising: The device body comprises a shell, a partition and a pump body, wherein the partition is fixed in the shell to separate the inner cavity of the shell into an upper accommodating cavity and a lower accommodating cavity, a first mounting hole is provided on the partition, a first control valve is provided in the first mounting hole, a liquid inlet and a liquid outlet communicating with the lower accommodating cavity are provided on the shell, the liquid inlet and the liquid outlet are used to communicate with two ends of the electrolytic cell respectively, and two ends of the pump body are communicated with the lower accommodating cavity and the first mounting hole respectively; A filter assembly, the filter assembly comprising a first filter element and a second filter element sequentially arranged in the upper accommodating cavity along a height direction; and A sedimentation mechanism is arranged in the lower accommodating chamber.

[0010] In some embodiments, the shell includes a lower shell, an upper shell and an upper cover, the lower shell is detachably connected to one end of the upper shell, the upper cover is detachably connected to the other end of the upper shell, the partition is fixed in the lower shell, the first filter element is arranged in the upper shell, and the second filter element is arranged in the lower shell.

[0011] In some embodiments, a first pressurizing port and a tail water inlet are provided on the upper shell, a first pressurizing port is provided with a first pressurizing valve, the first pressurizing port is used to communicate with the outlet of the gas injection pressurizing device, a tail water inlet valve is provided on the tail water inlet, and the tail water inlet is used to supply the effluent from the sewage treatment plant.

[0012] In some embodiments, a dosing port is provided on the lower shell body, a dosing valve is provided on the dosing port, and the dosing port is used to add a complexing agent; a second pressurizing port is also provided on the lower shell body, a second pressurizing valve is provided on the second pressurizing port, and the second pressurizing port is used to connect with the outlet of the gas injection pressurizing device.

[0013] In some embodiments, the first filter element includes a first bracket and a plurality of first filter membranes, the first bracket is fixed in the upper shell, the first bracket is provided with a plurality of first fixing holes, and each of the first filter membranes is installed in a corresponding first fixing hole.

[0014] In some embodiments, the second filter element includes a second bracket and a plurality of second filter membranes, the second bracket is fixed in the lower shell, the second bracket is provided with a plurality of second fixing holes, and each of the second filter membranes is installed in a corresponding second fixing hole.

[0015] In some embodiments, the sedimentation mechanism includes a baffle and a plurality of inclined plates, wherein the baffle is fixed to the lower end of the partition, the baffle is inclined, and the height of the lower end thereof is higher than the height of the liquid inlet, and a left chamber and a right chamber are formed on both sides of the baffle respectively, the left chamber is connected to the liquid outlet, and the upper side of the right chamber is connected to the first mounting hole, and each of the inclined plates is evenly spaced, inclined and parallel to the left chamber.

[0016] In some embodiments, the sedimentation mechanism also includes a horizontal plate, which is fixed between the baffle and the lower shell, and a second mounting hole is opened on the horizontal plate, a second control valve is arranged in the second mounting hole, and both ends of the pump body are respectively connected to the first mounting hole and the second mounting hole.

[0017] In some embodiments, a liquid inlet valve is provided on the liquid inlet, and a liquid outlet valve is provided on the liquid outlet.

[0018] The present invention also provides a water treatment method for producing hydrogen by electrolysis of sewage plant effluent, which is applicable to the water treatment device for producing hydrogen by electrolysis of sewage plant effluent, and comprises the following steps: S1. After one round of electrolysis is completed, the first control valve is closed, and the alkaline electrolyte in the electrolytic cell is passed into the lower accommodating chamber through the liquid inlet. The alkaline electrolyte flows through the sedimentation mechanism and then flows back to the electrolytic cell from the liquid outlet to form a cycle. In this process, the sedimentation mechanism can remove the precipitate in the alkaline electrolyte. S2. After the precipitation in the alkaline electrolyte is completely removed, the first control valve and the pump body are opened, and the alkaline electrolyte in the lower receiving chamber is pumped into the upper receiving chamber through the pump body, and then the first control valve is closed, and then the tail water is passed into the upper receiving chamber. After the tail water passes through the first filter element, it is fully mixed with the alkaline electrolyte, so that the Ca in the tail water can be 2+ Mg 2+ , Mn 2+ The reaction generates Ca(OH) 2 Mg(OH) 2 and Mn(OH) 2 precipitation; S3, open the first control valve, open the pump body in reverse, and the new electrolyte, driven by the pump body, passes through the second filter element and enters the lower accommodating chamber, then close the first control valve, and then pass the new electrolyte into the electrolytic cell to prepare for the next round of electrolytic hydrogen production process.

[0019] Compared with the prior art, the water treatment device for electrolyzing hydrogen from sewage treatment plant effluent provided by the present invention has the following beneficial effects: the alkaline electrolyte is mixed with the tail water in advance through the alkaline conditions inherent in the alkaline electrolysis process, so that the metal cations in the tail water are precipitated in advance and removed by membrane filtration, and then the mixed solution is passed into the electrolytic cell, thereby efficiently and economically removing impurities without relying on expensive reverse osmosis devices, and reducing the amount of precipitation in the electrolytic cell; at the same time, the precipitation generated in the alkaline electrolysis process can be effectively removed through the sedimentation mechanism, ensuring the exposure of the active sites, thereby improving the catalytic activity and stability of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a water treatment device for producing hydrogen by electrolysis of effluent from a sewage plant provided by an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the structure of the water treatment device; Figure 3 yes Figure 1 A schematic diagram of the three-dimensional structure of the shell; Figure 4 yes Figure 1 A schematic cross-sectional view of a water treatment device; Description of the reference numerals: 1-device body, 11-housing, 111-lower housing, 1111-liquid inlet, 1112-liquid outlet, 1113-dosing port, 1114-dosing valve, 1115-drainage port, 1116-liquid inlet valve, 1117-liquid outlet valve, 1118-second pressurizing port, 1119-second pressurizing valve, 112-upper housing, 1121-first pressurizing port, 1122-tail water inlet, 1123-first pressurizing valve, 1124-tail water inlet valve, 1125- 13-upper cover, 12-partition, 121-first control valve, 13-pump body, 2-filter assembly, 21-first filter element, 211-first bracket, 2111-first fixing hole, 212-first filter membrane, 22-second filter element, 221-second bracket, 2211-second fixing hole, 222-second filter membrane, 3-sedimentation mechanism, 31-baffle, 32-inclined plate, 33-horizontal plate, 331-second control valve, 4-electrolyzer, 5-circulation pump, 6-heater. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] In order to solve the technical problem in the prior art that tail water is prone to rapid precipitation when in contact with the electrolyte, which hinders the exposure of active sites and thereby reduces the catalytic activity and stability of the electrode, the present invention provides a water treatment device for electrolyzing hydrogen from sewage plant effluent, which can reduce the amount of precipitation in the electrolytic cell, ensure the exposure of active sites, and thereby improve the catalytic activity and stability of the electrode.

[0023] See also Figure 1-Figure 4 , Figure 1 This is a schematic structural diagram of a water treatment device for producing hydrogen by electrolysis of effluent from a sewage treatment plant in one embodiment of the present invention. The water treatment device for producing hydrogen by electrolysis of effluent from a sewage treatment plant comprises a device body 1, a filtering component 2 and a sedimentation mechanism 3.

[0024] The device body 1 includes a shell 11, a partition 12 and a pump body 13. The partition 12 is fixed in the shell 11 to separate the inner cavity of the shell 11 into an upper accommodating chamber and a lower accommodating chamber. A first mounting hole is provided on the partition 12, and a first control valve 121 is arranged in the first mounting hole. A liquid inlet 1111 and a liquid outlet 1112 connected to the lower accommodating chamber are provided on the shell 11. The liquid inlet 1111 and the liquid outlet 1112 are used to be connected to the two ends of the electrolytic cell 4 respectively, and the two ends of the pump body 13 are connected to the lower accommodating chamber and the first mounting hole respectively; in this embodiment, the pump body 13 needs to meet the requirements of normal use in a strong alkaline environment, and at the same time meet the requirements of forward and reverse steering, so that the alkaline electrolyte can be pumped upward into the upper accommodating chamber to react with the tail water, and the reacted electrolyte can be discharged downward to the lower accommodating chamber and finally enter the electrolytic cell.

[0025] The filter assembly 2 includes a first filter element 21 and a second filter element 22 which are sequentially arranged in the upper accommodating cavity along the height direction.

[0026] The sinking mechanism 3 is arranged in the lower accommodating chamber.

[0027] Working process: After one round of electrolysis is completed, the first control valve 121 and the second control valve 331 are still in the closed state, the flow rate of the circulation pump 5 is reduced, and the alkaline electrolyte in the electrolytic cell 4 is passed into the lower accommodating chamber through the liquid inlet 1111. The alkaline electrolyte flows through the sedimentation mechanism 3 and then flows back to the electrolytic cell 4 from the liquid outlet 1112 to form a cycle. In this process, the slow circulation flow rate causes the sedimentation mechanism 3 to accumulate the precipitate generated by the concentration of the alkaline electrolyte, and finally discharges it from the sewage outlet 1115; after the precipitate in the alkaline electrolyte is completely removed, the first control valve 121 and the pump body 13 are opened, and the alkaline electrolyte in the lower accommodating chamber is pumped into the upper accommodating chamber through the pump body 13, and then the first control valve 121 is closed, and then the tail water (i.e., the effluent from the sewage treatment plant) is passed into the upper accommodating chamber. After the tail water passes through the first filter element 21, it is fully mixed with the alkaline electrolyte, so that the Ca in the tail water can be 2+ Mg 2+ , Mn 2+ Heavy metals react to generate Ca(OH) 2 Mg(OH) 2 、Mn(OH) 2 Sedimentation; the first filter element 21 can remove the original sediment in the tail water; open the first control valve 121, reversely open the pump body 13, and the new electrolyte (i.e., the liquid after the tail water and the electrolyte are mixed) is driven by the pump body 13 to pass through the second filter element 22 and enter the lower accommodating chamber, and then close the first control valve 121, and then the new electrolyte is introduced into the electrolytic cell 4 to prepare for the next round of electrolytic hydrogen production process, while the sediment produced by the reaction of the tail water and the alkaline electrolyte is blocked on the second filter element 22.

[0028] The technical solution provided by the present invention uses the alkaline conditions inherent in the alkaline electrolysis process to mix the alkaline electrolyte with the tail water in advance, so as to promote the early precipitation of metal cations in the tail water and remove them through membrane filtration, and then pass the mixed solution into the electrolytic cell, thereby efficiently and economically removing impurities without relying on expensive reverse osmosis devices, and reducing the amount of precipitation in the electrolytic cell; at the same time, the precipitation generated in the alkaline electrolysis process can be effectively removed by the sedimentation mechanism, ensuring the exposure of active sites, thereby improving the catalytic activity and stability of the electrodes in the electrolytic cell.

[0029] It should be pointed out that the existing alkaline electrolyte circulation system also includes a circulation pump 5 and a heater 6. The inlet of the circulation pump 5 is connected to one end of the electrolytic cell 4, the outlet of the circulation pump 5 is connected to the liquid inlet 1111, one end of the heater 6 is connected to the other end of the electrolytic cell 4, and the other end of the heater 6 is connected to the liquid outlet 1112.

[0030] In one embodiment, see Figure 2-Figure 4 The outer shell 11 includes a lower shell 111, an upper shell 112 and an upper cover 113. The lower shell 111 is detachably connected to one end of the upper shell 112, and the upper cover 113 is detachably connected to the other end of the upper shell 112. The partition 12 is fixed in the lower shell 111, the first filter element 21 is arranged in the upper shell 112, and the second filter element 22 is arranged in the lower shell 111.

[0031] In one embodiment, see Figure 2-Figure 4 The upper shell 112 is provided with a first pressurizing port 1121 and a tail water inlet 1122. The first pressurizing port 1121 is provided with a first pressurizing valve 1123. The first pressurizing port 1121 is used to communicate with the outlet of the gas injection pressurizing device, so that the upper accommodating cavity can be pressurized to promote the mixed liquid to pass through the first filter element 21. The tail water inlet 1122 is provided with a tail water inlet valve 1124. The tail water inlet 1122 is used to supply the effluent (i.e., tail water) of the sewage treatment plant.

[0032] In one embodiment, see Figure 2-Figure 4 The lower shell 111 is provided with a dosing port 1113, and a dosing valve 1114 is provided on the dosing port 1113. The dosing port 1113 is used to add a complexing agent. In this embodiment, the complexing agent is EDTA complexing agent, which is used to remove the residual Ca in the alkali solution. 2+ .

[0033] In one embodiment, see Figure 2-Figure 4The first filter element 21 includes a first bracket 211 and a plurality of first filter membranes 212. The first bracket 211 is fixed in the upper shell 112. The first bracket 211 is provided with a plurality of first fixing holes 2111. Each of the first filter membranes 212 is installed in the corresponding first fixing holes 2111. In this embodiment, the first filter membrane 212 can be a microfiltration membrane or an ultrafiltration membrane. If the tail water passes smoothly, the gas injection pressurization device may not be started. Otherwise, the upper cover 113 needs to be sealed and the gas injection pressurization device is simultaneously used. When the first filter membrane 212 is seriously contaminated, the upper cover 113 can be opened to replace a new membrane.

[0034] In one embodiment, see Figure 2-Figure 4 The second filter element 22 includes a second bracket 221 and a plurality of second filter membranes 222. The second bracket 221 is fixed in the lower shell 111. The second bracket 221 is provided with a plurality of second fixing holes 2211. Each second filter membrane 222 is installed in the corresponding second fixing hole 2211. In this embodiment, the second filter membrane 222 can be a microfiltration membrane or an ultrafiltration membrane. If the tail water passes smoothly, the gas injection pressurization device may not be started. Otherwise, the upper cover 113 needs to be sealed and the gas injection pressurization device needs to be started. When the second filter membrane 222 is seriously contaminated, the upper shell 112 can be disassembled to expose the second filter element 22 and replace it with a new membrane.

[0035] In one embodiment, see Figure 2-Figure 4 The sedimentation mechanism 3 includes a baffle 31 and a plurality of inclined plates 32. The baffle 31 is fixed to the lower end of the partition 12. The baffle 31 is tilted, and the height of the lower end thereof is higher than the height of the liquid inlet 1111. The two sides of the baffle 31 form a left chamber and a right chamber respectively. The left chamber is connected to the liquid outlet 1112, and the upper side of the right chamber is connected to the first mounting hole. Each inclined plate 32 is evenly spaced, tilted and parallel to the left chamber. When in use, the electrolyzed water slowly flows upward through the gaps between the inclined plates 32 to the liquid outlet 1112. In this process, the sediment in the electrolyzed water will descend along the inclined plates 32 until it is deposited at the bottom of the lower shell 111. A sewage outlet 1115 is provided at the bottom of the lower shell 111. A sewage outlet 1115 is provided with a sewage valve. By opening the sewage valve regularly, the sediment accumulated at the sewage outlet 1115 can be cleaned.

[0036] In one embodiment, see Figure 2-Figure 4 The sedimentation mechanism 3 also includes a transverse plate 33, which is fixed between the baffle 31 and the lower shell 111. A second mounting hole is opened on the transverse plate 33, and a second control valve 331 is arranged in the second mounting hole. The two ends of the pump body 13 are respectively connected to the first mounting hole and the second mounting hole.

[0037] In one embodiment, see Figure 2-Figure 4 The liquid inlet 1111 is provided with a liquid inlet valve 1116 , and the liquid outlet 1112 is provided with a liquid outlet valve 1117 .

[0038] In one embodiment, see Figure 2-Figure 4 A second pressurizing port 1118 is also provided on the lower shell 111, and a second pressurizing valve 1119 is provided on the second pressurizing port 1118. The second pressurizing port 1118 is used to be connected to the outlet of the gas injection pressurizing device, so that the lower accommodating cavity can be pressurized to promote the mixed liquid to pass through the second filter element 22.

[0039] The present invention also provides a water treatment method for producing hydrogen by electrolysis of sewage plant effluent, which is applicable to the water treatment device for producing hydrogen by electrolysis of sewage plant effluent, and comprises the following steps: S1. After one round of electrolysis is completed, the first control valve 121 and the second control valve 331 are still in the closed state, the flow rate of the circulation pump 5 is reduced, and the alkaline electrolyte in the electrolytic cell 4 is passed into the lower accommodating chamber through the liquid inlet 1111. The alkaline electrolyte flows through the sedimentation mechanism 3 and then flows back to the electrolytic cell 4 from the liquid outlet 1112 to form a cycle. In this process, the slow circulation flow rate causes the sedimentation mechanism 3 to accumulate the precipitate generated by the concentration of the alkaline electrolyte, and finally discharges it from the sewage outlet 1115; S2. After the precipitation in the alkaline electrolyte is completely removed, the first control valve 121, the second control valve 331 and the pump body 13 are opened, and the alkaline electrolyte in the lower accommodating chamber is pumped into the upper accommodating chamber through the pump body 13. At this time, the liquid level of the alkaline electrolyte in the upper accommodating chamber is at the liquid level B. Then the first control valve 121 and the second control valve 331 are closed, and then the liquid inlet valve 1116 is opened to pass a certain amount of tail water (i.e., the effluent from the sewage treatment plant) into the upper accommodating chamber, and then the liquid inlet valve 1116 is closed. After the tail water passes through the first filter element 21, it is fully mixed with the alkaline electrolyte. At this time, the liquid level reaches the liquid level C, which can make the Ca in the tail water 2+ Mg 2+ , Mn 2+ The reaction generates Ca(OH) 2 Mg(OH) 2 and Mn(OH) 2 Then open the dosing valve 1114, and introduce the complexing agent into the upward receiving chamber to remove the residual Ca in the alkali solution. 2+ It should be pointed out that due to Ca(OH) 2 It is slightly soluble in water. Therefore, simply reacting with alkaline electrolyte cannot remove the Ca in the tail water. 2+ Therefore, in the present invention, the residual Ca in the alkali solution is removed by introducing a complexing agent into the upward receiving chamber. 2+ , which can completely remove Ca 2+ ; S3, open the first control valve 121 and the second control valve 331, and open the pump body 13 in reverse. Driven by the pump body 13, the new electrolyte (i.e., the liquid obtained by mixing tail water and electrolyte) passes through the second filter element 22 and enters the lower accommodating chamber. At this time, the liquid level reaches the liquid level A, and the first control valve 121 and the second control valve 331 are closed. The new electrolyte is then introduced into the electrolytic cell 4 through the circulation pump 5 to prepare for the next round of electrolytic hydrogen production process. The precipitate produced by the reaction of tail water and alkaline electrolyte is blocked on the second filter element 22.

[0040] The beneficial effects of the technical solution provided by the present invention include: (1) The alkaline electrolyte is mixed with the tail water in advance through the alkaline conditions inherent in the alkaline electrolysis process, so that the metal cations in the tail water are precipitated in advance and removed by membrane filtration. The mixed solution is then passed into the electrolytic cell, thereby efficiently and economically removing impurities without relying on expensive reverse osmosis equipment and reducing the amount of precipitation in the electrolytic cell. (2) The precipitation generated during alkaline electrolysis can be effectively removed through the sedimentation mechanism, ensuring the exposure of active sites, thereby improving the catalytic activity and stability of the electrodes in the electrolytic cell; (3) A removable membrane is provided. When the filtration effect is reduced due to membrane contamination, it can be repaired by removing the water tank and replacing a new membrane; (4) A membrane support is provided to accommodate different types of membranes to achieve electrolyte clarification effects, including microfiltration and ultrafiltration. An additional top pressurization device can be provided to ensure the normal operation of the ultrafiltration system.

[0041] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A water treatment device for producing hydrogen by electrolysis of sewage plant effluent, characterized in that: include: The device body comprises a shell, a partition and a pump body, wherein the partition is fixed in the shell to separate the inner cavity of the shell into an upper accommodating cavity and a lower accommodating cavity, a first mounting hole is provided on the partition, a first control valve is provided in the first mounting hole, a liquid inlet and a liquid outlet communicating with the lower accommodating cavity are provided on the shell, the liquid inlet and the liquid outlet are used to communicate with two ends of the electrolytic cell respectively, and two ends of the pump body are communicated with the lower accommodating cavity and the first mounting hole respectively; A filter assembly, the filter assembly comprising a first filter element and a second filter element sequentially arranged in the upper accommodating cavity along a height direction; and A sedimentation mechanism is arranged in the lower accommodating chamber.

2. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 1, characterized in that: The shell includes a lower shell, an upper shell and an upper cover. The lower shell is detachably connected to one end of the upper shell, and the upper cover is detachably connected to the other end of the upper shell. The partition is fixed in the lower shell, the first filter element is arranged in the upper shell, and the second filter element is arranged in the lower shell.

3. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 2, characterized in that: A first pressurizing port and a tail water inlet are provided on the upper shell. A first pressurizing port is provided with a first pressurizing valve. The first pressurizing port is used to communicate with the outlet of the gas injection pressurizing device. A tail water inlet valve is provided on the tail water inlet. The tail water inlet is used to supply the effluent from the sewage treatment plant.

4. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 2, characterized in that: The lower shell is provided with a dosing port, on which a dosing valve is provided, and the dosing port is used to add a complexing agent; the lower shell is also provided with a second pressurizing port, on which a second pressurizing valve is provided, and the second pressurizing port is used to communicate with the outlet of the gas injection pressurizing device.

5. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 2, characterized in that: The first filter element includes a first bracket and a plurality of first filter membranes. The first bracket is fixed in the upper shell. The first bracket is provided with a plurality of first fixing holes. Each of the first filter membranes is installed in a corresponding first fixing hole.

6. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 2, characterized in that: The second filter element includes a second bracket and a plurality of second filter membranes. The second bracket is fixed in the lower shell. The second bracket is provided with a plurality of second fixing holes. Each of the second filter membranes is installed in a corresponding second fixing hole.

7. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 1, characterized in that: The sedimentation mechanism includes a baffle and a plurality of inclined plates, wherein the baffle is fixed to the lower end of the partition, the baffle is inclined, and the height of the lower end thereof is higher than the height of the liquid inlet, and a left chamber and a right chamber are formed on both sides of the baffle respectively, the left chamber is connected to the liquid outlet, and the upper side of the right chamber is connected to the first mounting hole, and each of the inclined plates is evenly spaced, inclined and parallel to the left chamber.

8. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 7, characterized in that: The sedimentation mechanism also includes a transverse plate, which is fixed between the baffle and the lower shell. A second mounting hole is opened on the transverse plate, and a second control valve is arranged in the second mounting hole. Both ends of the pump body are connected to the first mounting hole and the second mounting hole respectively.

9. The water treatment device for producing hydrogen by electrolysis of sewage plant effluent according to claim 1, characterized in that: The liquid inlet is provided with a liquid inlet valve, and the liquid outlet is provided with a liquid outlet valve.

10. A water treatment method for producing hydrogen by electrolysis of sewage plant effluent, characterized in that: The water treatment device for producing hydrogen by electrolysis of sewage plant effluent is applicable to any one of claims 1 to 9, and comprises the following steps: S1. After one round of electrolysis is completed, the first control valve and the second control valve are still in the closed state, the circulation pump flow rate is reduced, and the alkaline electrolyte in the electrolytic cell is passed into the lower accommodating chamber through the liquid inlet. The alkaline electrolyte flows through the sedimentation mechanism and then returns to the electrolytic cell from the liquid outlet to form a cycle. In this process, the slow circulation flow rate causes the sedimentation mechanism to accumulate the precipitate generated by the concentration of the alkaline electrolyte, and finally discharges it from the sewage outlet; S2. After the precipitation in the alkaline electrolyte is completely removed, the first control valve, the second control valve and the pump body are opened, and the alkaline electrolyte in the lower accommodating chamber is pumped into the upper accommodating chamber through the pump body. At this time, the liquid level of the alkaline electrolyte in the upper accommodating chamber is at liquid level B, and then the first control valve and the second control valve are closed, and then the inlet valve is opened to pass a certain amount of tail water (i.e., effluent from the sewage treatment plant) into the upper accommodating chamber, and then the inlet valve is closed. After the tail water passes through the first filter element, it is fully mixed with the alkaline electrolyte. At this time, the liquid level reaches liquid level C, which can make the Ca in the tail water 2+ Mg 2+ , Mn 2+ The reaction generates Ca(OH)2, Mg(OH)2 and Mn(OH)2 precipitation; then open the dosing valve and introduce the complexing agent into the upper chamber to remove the residual Ca in the alkali solution. 2+ ; S3. Open the first control valve and the second control valve, and open the pump body in reverse. Driven by the pump body, the new electrolyte (i.e., the liquid after the tail water and the electrolyte are mixed) passes through the second filter element and enters the lower accommodating chamber. At this time, the liquid level reaches the liquid level A. Close the first control valve and the second control valve, and then pass the new electrolyte into the electrolytic cell through the circulation pump to prepare for the next round of electrolytic hydrogen production process. The precipitate produced by the reaction of the tail water and the alkaline electrolyte is blocked on the second filter element.

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