Comprehensive treatment system for production wastewater

Abstract

The utility model discloses a production wastewater comprehensive treatment system which comprises a water pump, a heat exchanger set, a catalysis tank, an electrolytic bath and a salt substance recovery unit, the heat exchanger set comprises a plurality of heat exchangers connected in series, a supporting structure used for containing catalyst filler is arranged in the catalysis tank, and an electrode used for conducting electro-catalytic decomposition on wastewater is arranged in the electrolytic bath; the top of the electrolytic cell is provided with a gas-collecting hood for collecting gas generated in the electro-catalysis process, and the upper part of the electrolytic cell close to the gas-collecting hood is provided with an overflow port; a cold side outlet of the heat exchanger group is communicated with a water inlet in the bottom of the catalytic tank; a water outlet in the top of the catalytic tank is communicated with a hot side inlet of the heat exchanger group; a hot side outlet of the heat exchanger group is communicated with a water inlet of the electrolytic bath; an overflow port of the electrolytic bath is communicated with the salt material recovery unit; and a steam input pipe for increasing the temperature of the wastewater to be treated is connected to a pipeline between the cold side outlet of the heat exchanger group and the water inlet of the catalysis tank. Pollutants in the production wastewater can be specifically and efficiently removed, salt substances with high purity can be recycled, the cost of comprehensive treatment of the wastewater is reduced, deep utilization of energy is achieved, the production value of enterprises is improved, and good economic benefits and environmental protection values are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment, in particular to a comprehensive production wastewater treatment system. Background Art

[0002] Production wastewater from the fields of food, medicine, chemical industry, etc. usually has the characteristics of high salt content, high ammonia nitrogen and high COD. It is a type of wastewater that is difficult to treat. Due to its high salt content and microbial intolerance, the commonly used biological oxidation method has poor treatment effect. COD (chemical oxygen demand) is a chemical method to measure the equivalent amount of oxygen consumed when organic matter in water is oxidized by strong oxidants. It is used to indicate the amount of organic matter in water. The catalytic oxidation method is more effective in removing organic matter and reducing COD, but it has almost no treatment effect on salt and ammonia nitrogen; electrolysis technology can remove ammonia nitrogen and organic matter at the same time, but it consumes a lot of electricity and it is difficult to directly reduce all pollutants to the standards that meet the treatment requirements; although the coagulation and sedimentation method can remove ammonia nitrogen, the amount of flocculant required is often large, the treatment cost is high, and it may cause secondary pollution, resulting in excessive phosphorus content in the effluent; stripping method and ammonia evaporation process are commonly used methods to remove ammonia nitrogen, but the stripping method When treating wastewater, it is necessary to first adjust the pH of the wastewater to about 11 and introduce air, which is easy to cause scaling. In addition, the low-temperature stripping time is long, the efficiency is low, and the energy consumption of introducing air for a long time is high. The ammonia gas blown out needs to be absorbed by acid liquid. The ammonia nitrogen in the treated wastewater is still high, and it needs to be combined with other processes to be completely treated; the ammonia evaporation process also needs to adjust the pH first, and then use steam as a heat source, which consumes a lot of energy. It also needs circulating water to condense the evaporated gas. In actual applications, there will still be about 300 mg / L of ammonia nitrogen residue in the treated wastewater, which also needs to be combined with other processes to be completely treated; membrane filtration technology uses different membranes to remove ammonia nitrogen and salt respectively, and the membrane cost and maintenance cost are high. It is difficult for a single treatment process to achieve the treatment of all pollutants, accompanied by problems such as high cost or secondary pollution, and it is impossible to meet the treatment requirements for this type of wastewater. Therefore, in actual applications, various technologies need to be designed and combined to treat production wastewater.

[0003] The existing technology for treating wastewater with high salt content, high ammonia nitrogen and high COD can often only treat each pollutant separately, such as removing organic matter through catalytic oxidation technology, removing ammonia nitrogen through stripping or ammonia evaporation process and combining it with the treatment of chemicals to meet the ammonia nitrogen removal requirements, and separating salts through membrane filtration. However, it is difficult to effectively combine the various treatment methods, resulting in cumbersome overall treatment process steps, high energy consumption, and easily affected treatment effects. For example, when production needs to recover salt substances in wastewater, the organic matter and ammonia nitrogen in the wastewater must be removed first and then the salt can be recovered by evaporation and crystallization. The wastewater cannot be directly evaporated and crystallized because, on the one hand, the salt obtained by direct evaporation has more impurities and is yellow in color, which cannot meet the recycling standards and can only be treated as waste; on the other hand, the mother liquor after direct evaporation and crystallization not only greatly increases the concentration of pollutants, but also makes the pollutants more complex and more difficult to handle, causing problems for environmental protection and sewage discharge pressure; therefore, if ammonia nitrogen is removed by ammonia evaporation process, it will directly affect the recovery of salt; if ammonia nitrogen is removed by stripping, it needs to be done at low temperature, and the wastewater temperature is high after catalytic oxidation to remove organic matter, and there will still be waste of residual heat even after heat is recovered by heat exchange.

[0004] Therefore, in order to achieve low-cost and efficient treatment of high-salt, high-ammonia nitrogen and high-COD wastewater, as well as the recycling of salt resources in the wastewater, it is necessary to design a scientific and reasonable comprehensive treatment system to meet environmental protection requirements while improving production value. Utility Model Content

[0005] In order to solve at least one of the problems mentioned in the background technology, an embodiment of the present application provides a comprehensive treatment system for production wastewater, which electrolyzes the production wastewater with a higher temperature after catalytic oxidation to efficiently remove organic matter and ammonia nitrogen, and recovers and purifies the salt-containing wastewater with higher purity after electrolysis, organically combines catalytic oxidation technology and electrolysis technology, improves wastewater treatment efficiency and energy utilization, and solves the problem that salt substances are difficult to recycle.

[0006] The embodiment of the present application provides a comprehensive treatment system for production wastewater, including a water pump, a heat exchanger group, a catalytic tank, an electrolytic cell and a salt substance recovery unit, wherein the heat exchanger group includes a plurality of heat exchangers connected in series, the catalytic tank is provided with a support structure for placing catalyst fillers, the electrolytic cell is provided with electrodes for electrocatalytically decomposing wastewater, the top of the electrolytic cell is provided with a gas collecting hood for collecting gas generated during the electrocatalytic process, and the upper part of the electrolytic cell is provided with an overflow port near the gas collecting hood;

[0007] The water pump outlet is connected to the cold side inlet of the heat exchanger group, the cold side outlet of the heat exchanger group is connected to the water inlet at the bottom of the catalyst tank, the water outlet at the top of the catalyst tank is connected to the hot side inlet of the heat exchanger group, the hot side outlet of the heat exchanger group is connected to the water inlet of the electrolytic cell, and the overflow of the electrolytic cell is connected to the salt substance recovery unit;

[0008] A steam input pipe for increasing the temperature of the wastewater to be treated is connected to the pipeline between the cold side outlet of the heat exchanger group and the water inlet of the catalyst tank.

[0009] In an achievable embodiment, the heat exchanger is a coiled tube heat exchanger, the total number of the coiled tube heat exchangers is M, M is an integer ≥ 2, N of which are cross-connected heat exchangers, N is an integer 1≤N<M, and the rest are conventionally connected heat exchangers;

[0010] The tube side of the cross-connected heat exchanger and the shell side of the conventionally connected heat exchanger serve as cold side channels of the heat exchanger group, and the shell side of the cross-connected heat exchanger and the tube side of the conventionally connected heat exchanger serve as hot side channels of the heat exchanger group.

[0011] In a feasible implementation, the cross-connected heat exchanger is arranged in the hot side channel of the heat exchanger group where the wastewater temperature is 90-100°C.

[0012] In a feasible embodiment, the heat exchanger group includes two wound tube heat exchangers, one of which is a cross-connected heat exchanger, the cross-connected heat exchanger is arranged far away from the catalyst tank, and the conventionally connected heat exchanger is arranged close to the catalyst tank; the tube-side inlet of the cross-connected heat exchanger serves as the cold-side inlet of the heat exchanger group, the shell-side outlet of the conventionally connected heat exchanger serves as the cold-side outlet of the heat exchanger group, the tube-side inlet of the conventionally connected heat exchanger serves as the hot-side inlet of the heat exchanger group, and the shell-side outlet of the cross-connected heat exchanger serves as the hot-side outlet of the heat exchanger group.

[0013] In an achievable embodiment, the heat exchanger group includes four coiled tube heat exchangers, two of which are cross-connected heat exchangers, the two cross-connected heat exchangers are respectively a cross-connected heat exchanger I and a cross-connected heat exchanger II, and the two conventionally connected heat exchangers are respectively a conventionally connected heat exchanger I and a conventionally connected heat exchanger II, and the cross-connected heat exchanger I, the cross-connected heat exchanger II, the conventionally connected heat exchanger I and the conventionally connected heat exchanger II are connected in sequence;

[0014] The cross-connected heat exchanger I is arranged far away from the catalytic tank, and the conventionally connected heat exchanger II is arranged close to the catalytic tank. The tube-side inlet of the cross-connected heat exchanger I serves as the cold-side inlet of the heat exchanger group, and the shell-side outlet of the conventionally connected heat exchanger II serves as the cold-side outlet of the heat exchanger group. The tube-side inlet of the conventionally connected heat exchanger II serves as the hot-side inlet of the heat exchanger group, and the shell-side outlet of the cross-connected heat exchanger I serves as the hot-side outlet of the heat exchanger group.

[0015] In a feasible embodiment, a pressure gauge and a thermometer are respectively provided on the pipeline between the water pump outlet and the cold side inlet of the heat exchanger group, on the pipeline between the hot side outlet of the heat exchanger group and the water inlet of the electrolyzer, and on the pipeline between the cold side outlet of the heat exchanger group and the water inlet of the catalyst tank, and a thermometer is provided on the pipeline between the water outlet of the catalyst tank and the hot side inlet of the heat exchanger group.

[0016] In a feasible embodiment, the salt substance recovery unit includes a membrane filtration device or an evaporation crystallization device.

[0017] In an achievable embodiment, the electrolytic cell comprises a cell body, a plurality of longitudinally extending baffles are arranged in the cell body, the baffles comprise an upper baffle and a lower baffle, the upper baffle is connected to the top inner wall of the cell body, the lower baffle is connected to the bottom inner wall of the cell body, the upper baffles and the lower baffles are staggered one by one to divide the cell body into electrolytic chambers which are sequentially connected to each other;

[0018] Each electrolytic chamber is provided with a cathode and an anode which are arranged parallel to each other, and the cathode and the anode are electrically connected to a power source through a wire respectively.

[0019] In a feasible implementation, a sewage outlet is provided at the bottom of the tank body, and aeration plates are evenly laid inside the tank body near the bottom.

[0020] In a feasible embodiment, an anti-vortex baffle and a plurality of anti-vortex ribs are provided inside the catalytic tank, the anti-vortex ribs are connected to the water inlet of the catalytic tank, each of the anti-vortex ribs extends in the radial direction of the water inlet, the top of the anti-vortex rib is connected to the anti-vortex baffle, and the anti-vortex baffle extends in the horizontal direction.

[0021] In summary, the comprehensive treatment system for production wastewater provided by the present application organically combines catalytic oxidation technology with electrolysis technology. The effluent from catalytic oxidation enters the electrolytic cell for subsequent decomposition after heat exchange with the wastewater to be treated through a heat exchanger. The conductivity of wastewater with a certain temperature is enhanced, and the deep utilization of energy is realized. The organic matter and ammonia nitrogen in the production wastewater are removed in a targeted and efficient manner, which is economical and environmentally friendly, and is conducive to improving the production value of the enterprise. The wastewater after electrolysis can be simply recycled to obtain salt substances with higher purity, and no secondary pollution is generated, which has good economic benefits and environmental protection value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A system diagram of a comprehensive production wastewater treatment system provided in an embodiment of the present application;

[0024] Figure 2 Another structural schematic diagram of a heat exchanger group provided in an embodiment of the present application;

[0025] Figure 3 for Figure 2 Connection diagram of the intercooler side channel;

[0026] Figure 4 for Figure 2 Connection diagram of the medium heat side channel;

[0027] Figure 5 A schematic diagram of the structure of the catalyst tank provided in the embodiment of the present application;

[0028] Figure 6 for Figure 5 Center AA view.

[0029] Description of reference numerals:

[0030] 10-heat exchanger group; 101-cold side inlet; 102-cold side outlet; 103-hot side inlet; 104-hot side outlet; 11-cross-connected heat exchanger; 111-cross-connected heat exchanger I; 112-cross-connected heat exchanger II; 12-conventional connection heat exchanger; 121-conventional connection heat exchanger I; 122-conventional connection heat exchanger II; 20-catalytic tank; 21-catalyst filler; 22-support structure; 23-anti-vortex baffle; 24-anti-vortex rib plate; 30-electrolyzer; 31-gas collecting hood; 32-tank body; 33-baffle; 34-overflow port; 35-drainage port; 36-aeration plate; 40-water pump; 50-steam inlet pipe. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the embodiment of the present application. It is worth noting that the embodiments described in the drawings are only part of the embodiments of the present application, not all of the embodiments. That is, the embodiments described by the drawings are exemplary and are intended to be used to explain the present application, and cannot be understood as limiting the present application.

[0032] The following will be combined Figure 1 to Figure 6 The comprehensive production wastewater treatment system provided in the embodiment of the present application is described.

[0033] The present application embodiment provides a comprehensive treatment system for production wastewater, such as Figure 1 and Figure 5 As shown, it includes a water pump 40, a heat exchanger group 10, a catalytic tank 20, an electrolytic cell 30 and a salt recovery unit. The heat exchanger group 10 includes a plurality of heat exchangers connected in series. The catalytic tank 20 is provided with a support structure 22 for placing a catalyst filler 21. The electrolytic cell 30 is provided with electrodes for electrocatalytic decomposition of wastewater. The top of the electrolytic cell 30 is provided with a gas collecting hood 31 for collecting gases generated during the electrocatalytic process. An overflow port 34 is provided at the upper part of the electrolytic cell 30 near the gas collecting hood 31.

[0034] The outlet of the water pump 40 is connected to the cold side inlet 101 of the heat exchanger group 10, the cold side outlet 102 of the heat exchanger group 10 is connected to the water inlet at the bottom of the catalyst tank 20, the water outlet at the top of the catalyst tank 20 is connected to the hot side inlet 103 of the heat exchanger group 10, the hot side outlet 104 of the heat exchanger group 10 is connected to the water inlet of the electrolytic cell 30, and the overflow port 34 of the electrolytic cell 30 is connected to the salt substance recovery unit.

[0035] A steam input pipe 50 for increasing the temperature of the wastewater to be treated is connected to the pipeline between the cold side outlet 102 of the heat exchanger group 10 and the water inlet of the catalyst tank 20 .

[0036] Among them, the wastewater to be treated is pre-treated and fully mixed with the oxidant before entering this system for comprehensive treatment.

[0037] Generally, the shell side of the heat exchanger is used as the cold side channel and the tube side is used as the hot side channel. Alternatively, part of the shell side of the heat exchanger can be used as the hot side channel and the tube side can be used as the cold side channel as in the following case.

[0038] The wastewater after catalytic oxidation still has a certain temperature after heat exchange in the heat exchanger, the conductivity of the wastewater is enhanced, the current density is increased, the treatment effect of organic matter and ammonia nitrogen is better than conventional electrocatalysis, and electricity is saved. The electrode includes a cathode and an anode arranged oppositely, and the gas collecting hood 31 collects hydrogen generated by the cathode during electrocatalysis for subsequent treatment.

[0039] The overall process of the comprehensive treatment system for production wastewater of the embodiment of the present application is as follows: the wastewater to be treated flows from the cold side inlet 101 of the heat exchanger group 10 through the water pump 40, passes through the cold side channel for heat exchange and temperature rise, and then flows out from the cold side outlet 102; the wastewater to be treated is mixed with high-temperature steam through the steam input pipe 50 to the wastewater to be entered into the catalytic tank 20; the wastewater to be treated reaching the reaction temperature enters the catalytic tank 20, the organic matter in the wastewater is oxidized and decomposed, the COD of the wastewater is greatly reduced, and then discharged from the catalytic tank 20; the high-temperature catalytic reaction wastewater flows from the hot side inlet 103 of the heat exchanger group 10, passes through the hot side channel for heat exchange and temperature reduction, and then flows out from the hot side outlet 104, and then enters the electrolytic cell 30 for further treatment, the organic matter and ammonia nitrogen in the wastewater are electrocatalytically decomposed, and the gas collecting hood 31 collects the tail gas in the electrolytic cell 30; the upper clear liquid in the electrolytic cell 30 is discharged to the salt substance recovery unit through the overflow port 34, and the ammonia nitrogen and organic matter in the wastewater after catalytic oxidation treatment and electrolysis treatment are basically removed, and the salt substance with higher purity can be obtained by recycling treatment.

[0040] Exemplarily, the present application uses hydrogen peroxide as an oxidant, the catalyst filler 21 is a wet catalyst, and a low-temperature wet catalytic oxidation process (LDO) is used. The reaction time is 10 to 15 minutes. The shell side of each heat exchanger is used as the cold side channel of the heat exchanger group 10, and the tube side of each heat exchanger is used as the hot side channel. The LDO outlet water is heat exchanged and its temperature is controlled to be 70 to 90°C; the LDO outlet water enters the electrolytic cell 30 for electro-oxidation treatment to continue to reduce the organic matter and ammonia nitrogen pollutant content of the wastewater. Only simple operations are required in the subsequent recovery of salt substances that meet the reuse standards. After actual production tests, the temperature results are measured: the cold side inlet water temperature of the heat exchanger group 10 is about 30°C, the cold side outlet water temperature is about 110°C, the hot side inlet water temperature of the heat exchanger group 10 is about 150°C, and the hot side outlet water temperature is about 70°C.

[0041] The comprehensive production wastewater treatment system provided by the present application organically combines catalytic oxidation technology with electrolysis technology. The catalytic oxidation effluent enters the electrolytic cell 30 for subsequent decomposition after heat exchange with the wastewater to be treated through a heat exchanger. The conductivity of the wastewater is enhanced at a certain temperature, and the deep utilization of energy is achieved. The organic matter and ammonia nitrogen in the production wastewater are effectively removed in a targeted manner, which is economical and environmentally friendly and is conducive to improving the production value of the enterprise. The wastewater after electrolysis can be simply recycled to obtain salt substances with higher purity without causing secondary pollution, and has good economic benefits and environmental protection value.

[0042] In one possible implementation, Figures 1-2 As shown, the heat exchanger is a coiled tube heat exchanger, the total number of which is M, where M is an integer ≥ 2, of which N are cross-connected heat exchangers 11, where N is an integer 1≤N<M, and the rest are conventionally connected heat exchangers 12.

[0043] The tube side of the cross-connected heat exchanger 11 and the shell side of the conventionally connected heat exchanger 12 serve as the cold side channel of the heat exchanger group 10 , and the shell side of the cross-connected heat exchanger 11 and the tube side of the conventionally connected heat exchanger 12 serve as the hot side channel of the heat exchanger group 10 .

[0044] In general, the shell side of the heat exchanger usually uses cold water and the tube side uses hot water to reduce heat loss. In actual application, it is found that cross-using the shell side and tube side of some heat exchangers, that is, setting a cross-connected heat exchanger 11 with hot water running on the shell side and cold water running on the tube side, can achieve better heat exchange effect. The reasons for this heat exchange effect are as follows:

[0045] The shell side of the heat exchanger is relatively thick, and the distance that the water flows through is relatively short, so the water temperature in the shell side will be uneven, which will affect the overall heat exchange effect; the tube side of the heat exchanger is relatively thin, spirally arranged, and the path that the water flows through is relatively long, and the heat exchange is more uniform. By setting up a cross-connected heat exchanger 11, the cold water is heated more. Since the heat of the cold water is exchanged from the hot water, the hot water will also cool down more, and the heat loss will be reduced, thereby achieving a better heat exchange effect and increasing the heat exchange temperature by 5 to 10°C.

[0046] A temperature test was conducted on the comprehensive production wastewater treatment system equipped with the cross-connected heat exchanger 11. The outlet water temperature of the cold side of the heat exchanger group 10 was 115-120°C, and the outlet water temperature of the hot side was 60-65°C.

[0047] With this arrangement, the heat exchanger group 10 has a better heat exchange effect, and the system heat energy utilization rate is improved, which is beneficial to saving the power consumption of electrocatalysis and reducing the production and operation costs.

[0048] In a feasible implementation, the cross-connected heat exchanger 11 is arranged at a wastewater temperature of 90-100° C. in the hot side channel of the heat exchanger group 10 .

[0049] Among them, in actual applications, some wastewater is prone to scaling when the temperature rises, and some wastewater has solid precipitation when the temperature drops. When performing heat exchange operations on high-salt wastewater, it is found that when the temperature drops to dozens of degrees, salt crystals or precipitation will be precipitated in the wastewater. Therefore, wastewater with a temperature range that is prone to scaling is allowed to pass through the shell side of the cross-connected heat exchanger 11 as much as possible, giving full play to the advantages of the coarse shell side, which is not easy to clog and easy to clean. This setting can reduce the situation where the heat exchanger is prone to scaling, improve the reliability of system operation, and reduce the cost of operation, maintenance and cleaning.

[0050] In one possible implementation, Figure 1As shown, the heat exchanger group 10 includes two wound tube heat exchangers, one of which is a cross-connected heat exchanger 11, the cross-connected heat exchanger 11 is arranged far away from the catalyst tank 20, and the conventionally connected heat exchanger 12 is arranged close to the catalyst tank 20. The tube side inlet of the cross-connected heat exchanger 11 serves as the cold side inlet 101 of the heat exchanger group 10, the shell side outlet of the conventionally connected heat exchanger 12 serves as the cold side outlet 102 of the heat exchanger group 10, the tube side inlet of the conventionally connected heat exchanger 12 serves as the hot side inlet 103 of the heat exchanger group 10, and the shell side outlet of the cross-connected heat exchanger 11 serves as the hot side outlet 104 of the heat exchanger group 10.

[0051] With this arrangement, the outlet water of the catalyst tank 20 flows through the hot side channel of the heat exchanger group 10 in the order of tube side first and shell side for heat exchange and cooling, and the outlet water of the water pump 40 flows through the cold side channel of the heat exchanger group 10 in the order of tube side first and shell side for heat exchange and heating. This can improve the heat exchange effect while reducing the scaling problem of wastewater. The overall structure of the system is simple, the process design is scientific, and it is easy to install and maintain.

[0052] In one possible implementation, Figures 2 to 4 As shown, the heat exchanger group 10 includes four coiled tube heat exchangers, two of which are cross-connected heat exchangers 11, the two cross-connected heat exchangers are respectively cross-connected heat exchanger I 111 and cross-connected heat exchanger II 112, and the two conventionally connected heat exchangers 12 are respectively conventionally connected heat exchanger I 121 and conventionally connected heat exchanger II 122. The cross-connected heat exchanger I 111, the cross-connected heat exchanger II 112, the conventionally connected heat exchanger I 121 and the conventionally connected heat exchanger II 122 are connected in sequence.

[0053] The cross-connected heat exchanger I 111 is arranged away from the catalyst tank 20, and the conventionally connected heat exchanger II 122 is arranged close to the catalyst tank 20. The tube-side inlet of the cross-connected heat exchanger I 111 serves as the cold-side inlet 101 of the heat exchanger group 10, and the shell-side outlet of the conventionally connected heat exchanger II 122 serves as the cold-side outlet 102 of the heat exchanger group 10. The tube-side inlet of the conventionally connected heat exchanger II 122 serves as the hot-side inlet 103 of the heat exchanger group 10, and the shell-side outlet of the cross-connected heat exchanger I 111 serves as the hot-side outlet 104 of the heat exchanger group 10.

[0054] This arrangement allows for step-by-step heat exchange through multiple heat exchangers, ensuring a stable heat exchange effect and making the system generally applicable to various wastewater treatment requirements.

[0055] In one possible implementation, Figure 1As shown, pressure gauges and thermometers are respectively provided on the pipeline between the outlet of the water pump 40 and the cold side inlet 101 of the heat exchanger group 10, on the pipeline between the hot side outlet 104 of the heat exchanger group 10 and the water inlet of the electrolyzer 30, and on the pipeline between the cold side outlet 102 of the heat exchanger group 10 and the water inlet of the catalyst tank 20, and a thermometer is provided on the pipeline between the water outlet of the catalyst tank 20 and the hot side inlet 103 of the heat exchanger group 10.

[0056] This setting allows accurate and timely control and adjustment of the system based on real-time monitored data, thereby improving operational stability.

[0057] In a feasible embodiment, the salt substance recovery unit includes a membrane filtration device or an evaporation crystallization device.

[0058] Among them, after the wastewater is treated by catalytic oxidation and electrocatalysis in turn, the organic matter and ammonia nitrogen pollutants in the wastewater are effectively removed, and then desalination is carried out by membrane filtration, which is simple to operate and can make the membrane have a longer service life, avoiding the blockage and damage of the membrane by wastewater pollution; or the salt-containing wastewater after catalytic oxidation and electrocatalysis treatment is evaporated and concentrated, and finally evaporated and crystallized to obtain solid salt that meets the reuse standard, which can reduce evaporation energy consumption and make the mother liquor easy to handle. In this way, the clean recovery of salt substances can be achieved at a low cost, and good economic benefits can be achieved.

[0059] In one possible implementation, Figure 1 As shown, the electrolytic cell 30 includes a cell body 32, in which a plurality of longitudinally extending baffles 33 are provided, the baffles 33 include an upper baffle and a lower baffle, the upper baffle is connected to the top inner wall of the cell body 32, the lower baffle is connected to the bottom inner wall of the cell body 32, the upper baffles and the lower baffles are staggered one by one to divide the cell body 32 into electrolytic chambers which are sequentially connected to each other.

[0060] Each electrolytic chamber is provided with a cathode and an anode which are arranged parallel to each other, and the cathode and the anode are electrically connected to a power source through a wire respectively.

[0061] With this arrangement, the flow rate of the wastewater is reduced under the action of the baffle 33, so that the wastewater can be discharged from the overflow port 34 only after it has passed through each electrolytic chamber in turn and has been fully electrocatalytically decomposed. This can further improve the electrocatalytic efficiency, further reduce organic matter and ammonia nitrogen pollutants in the wastewater, and facilitate subsequent recovery and treatment.

[0062] In one possible implementation, Figure 1 As shown, a sewage outlet 35 is provided at the bottom of the tank body 32, and aeration plates 36 are evenly laid on the inner side of the tank body 32 near the bottom.

[0063] This arrangement allows for timely discharge of sludge to avoid clogging of the aeration disk, which is beneficial to efficient electrolysis and improves operational stability.

[0064] In one possible implementation, Figure 6 As shown, an anti-vortex baffle 23 and a plurality of anti-vortex ribs 24 are provided inside the catalytic tank 20. The anti-vortex ribs 24 are connected to the water inlet of the catalytic tank 20. Each anti-vortex rib 24 extends along the radial direction of the water inlet. The top of the anti-vortex rib 24 is connected to the anti-vortex baffle 23. The anti-vortex baffle 23 extends in the horizontal direction.

[0065] With this arrangement, the wastewater entering the catalytic tank 20 has a certain flow rate, and the anti-vortex baffle 23 and the anti-vortex rib plate 24 make the wastewater evenly distributed around, so that the wastewater can be kept in a first-in-first-out and last-in-last-out state for a certain residence time. This prevents the wastewater from rushing to a higher position in the tank and being discharged from the outlet before the residence time is reached, so that the wastewater can fully react in the catalytic tank 20 and improve the catalytic oxidation treatment efficiency.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A comprehensive treatment system for industrial wastewater, characterized in that: It includes a water pump, a heat exchanger group, a catalytic tank, an electrolytic cell and a salt recovery unit. The heat exchanger group includes a plurality of heat exchangers connected in series. The catalytic tank is provided with a support structure for placing catalyst fillers. The electrolytic cell is provided with electrodes for electrocatalytically decomposing wastewater. The top of the electrolytic cell is provided with a gas collecting hood for collecting gas generated during the electrocatalytic process. The upper part of the electrolytic cell is provided with an overflow port near the gas collecting hood. The water pump outlet is connected to the cold side inlet of the heat exchanger group, the cold side outlet of the heat exchanger group is connected to the water inlet at the bottom of the catalyst tank, the water outlet at the top of the catalyst tank is connected to the hot side inlet of the heat exchanger group, the hot side outlet of the heat exchanger group is connected to the water inlet of the electrolytic cell, and the overflow of the electrolytic cell is connected to the salt substance recovery unit; A steam input pipe for increasing the temperature of the wastewater to be treated is connected to the pipeline between the cold side outlet of the heat exchanger group and the water inlet of the catalyst tank.

2. The comprehensive production wastewater treatment system according to claim 1 is characterized in that: The heat exchanger is a coiled tube heat exchanger, the total number of the coiled tube heat exchangers is M, M is an integer ≥ 2, N of which are cross-connected heat exchangers, N is an integer 1≤N<M, and the rest are conventionally connected heat exchangers; The tube side of the cross-connected heat exchanger and the shell side of the conventionally connected heat exchanger serve as cold side channels of the heat exchanger group, and the shell side of the cross-connected heat exchanger and the tube side of the conventionally connected heat exchanger serve as hot side channels of the heat exchanger group.

3. The comprehensive production wastewater treatment system according to claim 2 is characterized in that: The cross-connected heat exchanger is arranged at a wastewater temperature of 90-100°C in the hot side channel of the heat exchanger group.

4. The comprehensive production wastewater treatment system according to claim 2 is characterized in that: The heat exchanger group includes two wound tube heat exchangers, one of which is a cross-connected heat exchanger, the cross-connected heat exchanger is arranged far away from the catalyst tank, and the conventionally connected heat exchanger is arranged close to the catalyst tank; the tube-side inlet of the cross-connected heat exchanger serves as the cold-side inlet of the heat exchanger group, the shell-side outlet of the conventionally connected heat exchanger serves as the cold-side outlet of the heat exchanger group, the tube-side inlet of the conventionally connected heat exchanger serves as the hot-side inlet of the heat exchanger group, and the shell-side outlet of the cross-connected heat exchanger serves as the hot-side outlet of the heat exchanger group.

5. The comprehensive production wastewater treatment system according to claim 2 is characterized in that: The heat exchanger group includes four coiled tube heat exchangers, two of which are cross-connected heat exchangers, the two cross-connected heat exchangers are respectively a cross-connected heat exchanger I and a cross-connected heat exchanger II, and the two conventionally connected heat exchangers are respectively a conventionally connected heat exchanger I and a conventionally connected heat exchanger II, and the cross-connected heat exchanger I, the cross-connected heat exchanger II, the conventionally connected heat exchanger I and the conventionally connected heat exchanger II are connected in sequence; The cross-connected heat exchanger I is arranged far away from the catalytic tank, and the conventionally connected heat exchanger II is arranged close to the catalytic tank. The tube-side inlet of the cross-connected heat exchanger I serves as the cold-side inlet of the heat exchanger group, and the shell-side outlet of the conventionally connected heat exchanger II serves as the cold-side outlet of the heat exchanger group. The tube-side inlet of the conventionally connected heat exchanger II serves as the hot-side inlet of the heat exchanger group, and the shell-side outlet of the cross-connected heat exchanger I serves as the hot-side outlet of the heat exchanger group.

6. The comprehensive production wastewater treatment system according to any one of claims 1 to 5, characterized in that: A pressure gauge and a thermometer are respectively provided on the pipeline between the water pump outlet and the cold side inlet of the heat exchanger group, on the pipeline between the hot side outlet of the heat exchanger group and the water inlet of the electrolyzer, and on the pipeline between the cold side outlet of the heat exchanger group and the water inlet of the catalyst tank. A thermometer is provided on the pipeline between the water outlet of the catalyst tank and the hot side inlet of the heat exchanger group.

7. The comprehensive production wastewater treatment system according to claim 6 is characterized in that: The salt substance recovery unit comprises a membrane filtration device or an evaporation crystallization device.

8. The comprehensive production wastewater treatment system according to claim 6 is characterized in that: The electrolytic cell comprises a cell body, wherein a plurality of longitudinally extending baffles are arranged in the cell body, wherein the baffles comprise an upper baffle and a lower baffle, wherein the upper baffle is connected to the inner wall of the top of the cell body, and the lower baffle is connected to the inner wall of the bottom of the cell body, and the upper baffles and the lower baffles are arranged alternately to divide the cell body into electrolytic chambers which are sequentially connected to each other; Each electrolytic chamber is provided with a cathode and an anode which are arranged parallel to each other, and the cathode and the anode are electrically connected to a power source through a wire respectively.

9. The comprehensive production wastewater treatment system according to claim 8, characterized in that: A sewage outlet is arranged at the bottom of the tank body, and aeration plates are evenly laid on the inner side of the tank body near the bottom.

10. The comprehensive production wastewater treatment system according to claim 6, characterized in that: An anti-vortex baffle and a plurality of anti-vortex ribs are provided inside the catalytic tank. The anti-vortex ribs are connected to the water inlet of the catalytic tank. Each of the anti-vortex ribs extends in the radial direction of the water inlet. The top of the anti-vortex rib is connected to the anti-vortex baffle. The anti-vortex baffle extends in the horizontal direction.

Images