Waste liquid evaporation and salt separation resource treatment system

Abstract

The application discloses a waste liquid evaporation and salt separation resource treatment system, and belongs to the field of desulfurization waste liquid treatment. The waste liquid evaporation and salt separation resource treatment system comprises, in sequence, an oxidation kettle, a decoloring tower, a first centrifugal separator, a vacuum evaporation kettle, a second centrifugal separator, a crystallization kettle and a third centrifugal separator. The liquid outlet end of a liquid inlet assembly is communicated with a liquid collecting ring. A plurality of nozzles are equidistantly and circumferentially spaced apart on the top of the liquid collecting ring and are all upwardly inclined towards the middle. One air outlet end of a gas distribution assembly extends to the upper part of the inside of the kettle body to spray air downward. The other air outlet end of the gas distribution assembly is located below the inside of the kettle body and has a plurality of gas distribution layers. Each stirring blade of a stirrer has one gas distribution layer below. Ammonium thiosulfate in the desulfurization waste liquid is completely converted into ammonium sulfate by a catalytic oxidation method, and then high-quality ammonium thiocyanate and ammonium sulfate are extracted by an evaporation and crystallization method.

Description

Technical Field

[0001] This invention belongs to the field of desulfurization wastewater treatment, and particularly relates to a wastewater evaporation and salt separation resource utilization system. Background Technology

[0002] The pre-ammonia desulfurization process has been widely used in the coking industry for desulfurization of coke oven gas in recent years. This process uses the ammonia naturally present in the coal gas as an alkali source and cobalt phthalocyanine (PDS) compounds as the main components as desulfurization and decyanation catalysts. It has low desulfurization operating costs, low investment, simple operation, high desulfurization and decyanation efficiency, and does not require an external alkali source. It is currently the most widely used desulfurization process in the coking industry. According to incomplete statistics, more than 200 enterprises nationwide have adopted this method for desulfurization, and all have achieved good results.

[0003] However, due to side reactions during the desulfurization process, byproduct salts such as ammonium thiocyanate, ammonium thiosulfate, and ammonium sulfate are generated and accumulate continuously. When the content of these byproduct salts in the desulfurization liquid exceeds 250 g / L, it will affect the desulfurization effect, increase energy consumption, and decrease desulfurization efficiency. The higher the byproduct salt content, the worse the desulfurization efficiency. In order to ensure desulfurization efficiency, it is necessary to discharge some desulfurization liquid and add some new desulfurization liquid to reduce the byproduct salt content in the desulfurization system. A coke oven gas desulfurization system with an annual coke production of 1 million tons needs to discharge more than 50 m3 of desulfurization liquid every day to basically ensure that the byproduct salt content in the desulfurization liquid does not exceed 250 g / L. At present, most coking plants in China use the coal-mixing incineration method to treat desulfurization wastewater, that is, mixing desulfurization wastewater into coal and sending it into the coke oven. However, this method reduces the calorific value of coal, produces a large amount of harmful gases after combustion, corrodes coke oven equipment, and the strong odor of ammonia and other substances in the wastewater creates an extremely poor operating environment during coal transportation. In addition, during the process of sending desulfurization wastewater to coal blending, it is impossible for all of it to remain in the coal. Nearly half of the desulfurization wastewater will seep into the ground, causing pollution to the earth and underground, resulting in serious secondary pollution. This method has not truly solved the problem of desulfurization wastewater pollution.

[0004] From another perspective, these substances are also high-value-added chemical products. Therefore, recovering high-value-added products from the discharged desulfurization liquid can balance the by-products in the desulfurization system, ensure desulfurization efficiency, eliminate environmental pollution, and generate certain economic benefits. This is a practical and feasible method for treating discharged desulfurization liquid.

[0005] Some research has been conducted both domestically and internationally on the treatment of desulfurization wastewater. A Japanese patent argues that recovering ammonium thiocyanate from desulfurization wastewater is extremely difficult because both ammonium thiosulfate and ammonium thiocyanate are highly soluble in water with very little difference in solubility, making separation based on solubility impossible. Therefore, the Japanese patent proposes an electrodialysis method. While this method can produce ammonium thiocyanate, its complex process, high equipment cost, and high power consumption have prevented its industrial-scale production.

[0006] Currently, a small number of coking plants in China use a gradient crystallization method for salt extraction. After ammonia is evaporated from the desulfurization wastewater, the solution is heated and concentrated based on its different solubilities for stepwise crystallization and salt extraction, yielding ammonium thiocyanate, ammonium thiosulfate, and ammonium sulfate. However, because the solubility of ammonium thiosulfate and ammonium thiocyanate is very similar, the purity of the extracted salt is very low, ranging from 50-70%. The investment is high, and the operation is complex. In particular, the large quantity of low-purity ammonium thiosulfate extracted has no market demand and is essentially useless waste. Therefore, this method does not solve the pollution problem and is not feasible.

[0007] Another method is solvent extraction, which involves extracting ammonium sulfate, ammonium thiosulfate, and ammonium thiocyanate from the desulfurization wastewater using organic chemical solvents, and then preliminarily separating them with a purity of 90-95%. This method has significant drawbacks. First, the use of organic solvents not only increases costs but also causes severe pollution during distillation due to the presence of organic solvents in the extracted solution, resulting in substandard exhaust emissions requiring secondary treatment. Second, organic solvents are flammable and explosive, posing significant risks during transportation and storage. Third, the extracted chemical raw materials have low purity, failing to meet national minimum standards, resulting in low market prices.

[0008] Based on the characteristics of desulfurization wastewater from coking plants and the results of domestic and international research, it is not difficult to see that the key issues in the recycling and treatment of desulfurization wastewater are: first, ammonium thiocyanate and ammonium thiosulfate have similar solubilities and are difficult to separate, resulting in low purity of the separated byproduct salts, which cannot meet market demand; second, there is no market demand for the large amount of ammonium thiosulfate extracted from desulfurization wastewater. Summary of the Invention

[0009] The purpose of this invention is to propose a waste liquid evaporation and salt desalination resource utilization system, which completely converts ammonium thiosulfate in desulfurization waste liquid into ammonium sulfate through catalytic oxidation, and then extracts high-quality ammonium thiocyanate and ammonium sulfate through evaporation and crystallization, thereby completely solving two key problems in the treatment of coke oven gas desulfurization waste liquid.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] The present invention provides a waste liquid evaporation and salt resource utilization treatment method for desulfurization waste liquid treatment, comprising the following steps: S1: The desulfurization waste liquid is fed into an oxidation kettle, and catalytic oxidation is carried out in the presence of a catalyst and air to convert ammonium thiosulfate in the desulfurization waste liquid into ammonium sulfate; S2: The desulfurization waste liquid after catalytic oxidation is decolorized, and solid-liquid separation is performed on the decolorized desulfurization waste liquid to separate sulfur; S3: The desulfurized waste liquid is vacuum evaporated, and ammonium sulfate crystals are precipitated by cooling. Solid-liquid separation is carried out under constant temperature, and the separated ammonium sulfate crystals are dried to obtain ammonium sulfate; S4: The filtrate after solid-liquid separation in step S3 enters a crystallization kettle to obtain ammonium thiocyanate crystals. Solid-liquid separation is performed on the ammonium thiocyanate crystals, and the separated filtrate is returned to step S3 for further vacuum evaporation. The separated ammonium thiocyanate crystals are dried to obtain ammonium thiocyanate.

[0012] Preferably, in step S1, the exhaust gas discharged from the oxidation reactor is condensed to condense the exhaust gas containing ammonia into ammonia water, which is then returned to the desulfurization system. The condensed exhaust gas is then washed and absorbed before being discharged in compliance with emission standards.

[0013] Preferably, in step S3, the steam from the vacuum evaporation process is condensed into water and reused as washing water or circulating cooling water.

[0014] The present invention also provides a waste liquid evaporation and desalination resource utilization treatment system for implementing the above-mentioned waste liquid evaporation and desalination resource utilization treatment method, comprising an oxidation kettle, a decolorization tower, a first centrifugal separator, a vacuum evaporation kettle, a second centrifugal separator, a crystallization kettle, and a third centrifugal separator connected in sequence. The outlet of the third centrifugal separator is connected to the vacuum evaporation kettle through a first reflux pipe. The oxidation kettle includes a kettle body, a gas distribution assembly, a stirrer, a liquid collection ring, a nozzle, and a liquid inlet assembly. A stirrer is fixed on the top of the kettle body, and the stirring end of the stirrer extends into the interior of the kettle body. The liquid collection ring is disposed inside the kettle body. The outlet end of the liquid inlet assembly is connected to the liquid collection ring. Multiple nozzles are equidistantly connected to the top of the liquid collection ring along the circumference, and the multiple nozzles are all inclined upward towards the center so that the sprayed liquid is upward and converges towards the center. One of the gas outlet ends of the gas distribution assembly extends to the upper part of the kettle body and is located above the nozzle, spraying air downward in a jet manner. The other gas outlet end of the gas distribution assembly is located at the lower part of the kettle body and has multiple gas distribution sections. Each stirring blade of the stirrer has a gas distribution section below it.

[0015] Preferably, the gas distribution assembly includes an oxidation blower, a gas booster pump, a gas distribution plate, a first gas distribution pipe, a second gas distribution pipe, a gas collecting seat, and gas distribution sections. The outlet of the oxidation blower is connected to the first gas distribution pipe and the second gas distribution pipe. A gas booster pump is installed on the first gas distribution pipe. The gas distribution plate is fixed to the top wall of the vessel body. The outlet end of the first gas distribution pipe is connected to the gas distribution plate. The bottom of the gas distribution plate has multiple radially distributed first gas outlet holes. A perforation is opened in the middle of the gas distribution plate. The gas collecting seat is fixed to the bottom wall of the vessel body. Multiple gas distribution sections are fixedly connected to the inner side wall of the gas collecting seat. Each gas distribution section includes multiple gas distribution sections that are equidistantly distributed along the circumference of the gas collecting seat. The top of each gas distribution section has linearly distributed second gas outlet holes.

[0016] Preferably, the stirrer includes a motor, a stirring shaft, a first helical blade, a second helical blade, and stirring blades. The motor is fixed to the top wall of the vessel body, and the stirring shaft is fixed to the bottom end of the motor. Three stirring blades are fixed at axial intervals on the lower part of the stirring shaft. Each stirring blade is located above a gas distribution section. The first helical blade is fixed on the stirring shaft between the upper and middle stirring blades, and the second helical blade is fixed on the stirring shaft between the lower and middle stirring blades. The first and second helical blades have opposite helical directions.

[0017] Preferably, a sleeve is provided at both the first and second helical blades, and the two sleeves respectively surround the first and second helical blades and are fixed to the air distribution section.

[0018] Preferably, the liquid inlet assembly includes a liquid inlet pump, a liquid inlet pipe, and a liquid booster pump. One end of the liquid inlet pipe is connected to the liquid inlet pump, and the other end of the liquid inlet pipe is connected to the liquid collection ring. The liquid booster pump is installed on the liquid inlet pipe.

[0019] Preferably, the oxidation reactor further includes a second reflux pipe and a reflux pump. One end of the second reflux pipe is fixedly connected to the bottom of the reactor body, and the other end of the second reflux pipe is fixedly connected to the liquid inlet pipe and is located between the liquid booster pump and the liquid inlet pump.

[0020] Preferably, the oxidation reactor also includes a liquid flow meter, a gas flow meter, and a control cabinet. A gas flow meter is installed on the first gas distribution pipe, and a liquid flow meter is installed on the liquid inlet pipe. The liquid flow meter, gas flow meter, reflux pump, liquid booster pump, liquid inlet pump, gas booster pump, oxidation blower, and agitator are all electrically connected to the control cabinet.

[0021] Preferably, the system further includes a first condenser, a second condenser, and a scrubbing tower. The first condenser is connected to the exhaust port of the oxidation reactor, the exhaust port of the first condenser is connected to the scrubbing tower, and the second condenser is connected to the steam exhaust port of the vacuum evaporation reactor.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. Ammonium thiosulfate, which has similar solubility to ammonium thiocyanate but is difficult to separate, is converted into ammonium sulfate, which has a significantly lower solubility, facilitating subsequent separation. The extracted products include ammonium sulfate, ammonium thiocyanate, and sulfur, meeting first-class quality standards and enjoying strong market demand. Extracting a large number of chemical products from desulfurization wastewater achieves energy conservation and emission reduction while simultaneously recycling resources, bringing significant economic benefits to enterprises—turning waste into treasure—a win-win situation. The process is simple, novel, reliable, advanced, and practical, solving the environmental pollution problem of desulfurization wastewater in coking plants and saving water. The entire treatment method adopts a closed-loop cycle, recovering all three products with zero emissions of waste gas, wastewater, and solid waste.

[0024] 2. The desulfurization wastewater is drawn into the collection ring via the inlet assembly and sprayed out through six nozzles. Since all six nozzles are centered and angled upwards, the sprayed wastewater collides and disperses in the central area above the nozzles, and mixes thoroughly with the air emitted from the upper outlet of the gas distribution assembly before falling into the lower part of the reactor. During the stirring process, the lower outlet of the gas distribution assembly provides air from the lower part of the reactor, mixing with the catalyst and desulfurization wastewater. Furthermore, because each stirring blade is located above a gas distribution section, the air supplied from the gas distribution section is immediately dispersed by the stirring blades upon entering the desulfurization wastewater, further improving mixing efficiency and uniformity, and enhancing the catalytic oxidation effect and efficiency.

[0025] 3. Air is distributed through the first air distribution pipe to the air distribution plate by an oxidation blower. A gas booster pump ensures high-pressure air ejection from the air distribution plate, allowing for better mixing with the high-pressure ejected desulfurization waste liquid. Air is then sent to the gas collection seat through the second air distribution pipe. This layered air distribution system, with its different distribution methods at the top and bottom, significantly improves the mixing of air with the desulfurization waste liquid and catalyst. The radially distributed first air outlet combined with the linearly distributed second air outlet ensures more widespread and uniform air distribution at their respective locations.

[0026] 4. Because the first and second helical blades are in opposite directions, they can simultaneously push the liquid towards the center or away from each other while stirring. The vertically arranged first and second helical blades and the horizontally arranged stirring blades can better achieve the mixing efficiency and effect of catalyst, desulfurization waste liquid, and air, thereby improving the efficiency and effect of catalytic oxidation.

[0027] 5. By cooperating with the sleeve and the first and second spiral blades, the effect of pushing the liquid is enhanced, further improving the mixing efficiency and effect.

[0028] 6. The installation of a reflux pump and a second reflux pipe enables the recycling of desulfurization wastewater, resulting in more thorough catalytic oxidation. Attached Figure Description

[0029] Figure 1 This is a system diagram of the waste liquid evaporation and salt separation resource utilization treatment of the present invention.

[0030] Figure 2 This is a schematic diagram of the main structure of the oxidation reactor of the present invention.

[0031] Figure 3 This is a top view schematic diagram of the liquid collecting ring and nozzle of the present invention.

[0032] Figure 4 This is a top view schematic diagram of the gas collecting seat and gas distribution section of the present invention.

[0033] Figure 5 This is a schematic diagram showing the fit between the sleeve, the first threaded blade, and the second threaded blade of the present invention.

[0034] Figure 6 This is a bottom view of the structure of the air distribution plate of the present invention.

[0035] Figure 7 This is a control block diagram of the present invention.

[0036] The labels in the attached diagram are as follows: 100-Oxidation kettle, 200-Decolorization tower, 300-First centrifuge, 400-Vacuum evaporation kettle, 500-Second centrifuge, 600-Crystallization kettle, 700-Third centrifuge, 800-First reflux pipe, 900-First condenser, 1000-Scrubbing tower, 1100-Second condenser, 1-Kettle body, 2-Gas distribution assembly, 21-Oxidation blower, 22-Gas booster pump, 23-Gas distribution plate, 24-First gas distribution pipe, 25-Second gas distribution pipe 26-Gas collecting seat, 27-Gas distribution section, 28-Perforation, 29-First air outlet, 210-Second air outlet, 3-Agitator, 31-Motor, 32-Agitator shaft, 33-First spiral blade, 34-Second spiral blade, 35-Agitator blade, 36-Sleeve, 4-Liquid collecting ring, 5-Nozzle, 6-Liquid inlet assembly, 61-Liquid inlet pump, 62-Liquid inlet pipe, 63-Liquid booster pump, 7-Second return pipe, 8-Return pump, 9-Liquid flow meter, 10-Gas flow meter, 11-Control cabinet. Detailed Implementation

[0037] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0038] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] The waste liquid evaporation and salt desalination resource utilization method provided in this embodiment is used for desulfurization waste liquid treatment and includes the following steps:

[0040] S1: The desulfurization wastewater containing ammonium thiosulfate and ammonium thiocyanate is fed into oxidation reactor 100. Catalytic oxidation is performed with the addition of a catalyst and air to convert the ammonium thiosulfate in the wastewater into ammonium sulfate. The catalyst is titanium dioxide particles. Ammonium thiocyanate and ammonium sulfate have significantly different solubilities, making them easy to separate. The exhaust gas from oxidation reactor 100 is then condensed in the first condenser 900 to remove ammonia-laden gas, which is returned to the desulfurization system. The condensed exhaust gas is then washed and absorbed in scrubbing tower 1000 before being discharged in compliance with standards.

[0041] S2: The desulfurization waste liquid after catalytic oxidation is decolorized by decolorization tower 200. The decolorization packing is activated carbon. The decolorized desulfurization waste liquid is separated into solid and liquid by the first centrifugal separator 300 to separate sulfur (purity ≥97%).

[0042] S3: The sulfur-free waste liquid is vacuum evaporated in a vacuum evaporator. After evaporation to a certain extent, it is cooled to precipitate ammonium sulfate crystals. Under constant temperature conditions, solid-liquid separation is performed in a second centrifugal separator 500. The separated ammonium sulfate crystals are dried to obtain ammonium sulfate (purity ≥98.5%), which is then packaged as the finished product. The steam generated during the vacuum evaporation process is condensed into water in a second condenser 1100 and reused as washing water or circulating cooling water.

[0043] S4: The filtrate after solid-liquid separation in step S3 enters the crystallization kettle 600. After evaporation and cooling crystallization, ammonium thiocyanate crystals are obtained. The ammonium thiocyanate crystals are then separated into solid and liquid components using a third centrifuge 700. The separated filtrate is returned to step S3 for further vacuum evaporation. The separated ammonium thiocyanate crystals are dried to obtain ammonium thiocyanate (purity ≥99%), which is then packaged for sale. This process achieves the resource utilization of waste liquid through evaporation and salt separation.

[0044] This invention converts ammonium thiosulfate, which has a similar solubility to ammonium thiocyanate but is difficult to separate, into ammonium sulfate, which has a significantly different solubility, facilitating subsequent separation. The extracted products include ammonium sulfate, ammonium thiocyanate, and sulfur, meeting first-class product standards and enjoying strong market demand. Extracting a large number of chemical products from desulfurization wastewater achieves energy conservation and emission reduction while simultaneously recycling resources, bringing significant economic benefits to enterprises and turning waste into treasure—a win-win situation. The process is simple, novel, reliable, advanced, and practical, solving the environmental pollution problem of desulfurization wastewater in coking plants and saving water. The entire treatment method adopts a closed-loop cycle, recovering all three products with zero emissions of waste gas, wastewater, and solid waste.

[0045] Economic benefit analysis:

[0046] Treating 100m³ of desulfurization wastewater per day 3 Based on a daily production of approximately 10 tons of ammonium thiocyanate, 15 tons of ammonium sulfate, and 3.5 tons of sulfur.

[0047] Operating costs:

[0048]

[0049] Product Value:

[0050]

[0051] Daily profit: 67750 - 23000 = 44750 yuan.

[0052] Therefore, the waste liquid evaporation and salt separation resource utilization method of the present invention has significant economic benefits.

[0053] like Figure 1-7As shown, this embodiment also provides a waste liquid evaporation and desalination resource recovery system for implementing the above-mentioned waste liquid evaporation and desalination resource recovery method. The system includes an oxidation reactor 100, a decolorization tower 200, a first centrifuge 300, a vacuum evaporation reactor 400, a second centrifuge 500, a crystallization reactor 600, and a third centrifuge 700 connected in sequence. The outlet of the third centrifuge 700 is connected to the vacuum evaporation reactor via a first reflux pipe 800. The oxidation reactor 100 includes a reactor body 1, a gas distribution assembly 2, a stirrer 3, a liquid collection ring 4, a nozzle 5, and a liquid inlet assembly 6. The stirrer 3 is fixed to the top of the reactor body 1. The stirring end extends into the interior of the vessel body 1. The liquid collecting ring 4 is located inside the vessel body 1. The liquid outlet of the liquid inlet assembly 6 communicates with the liquid collecting ring 4. Six nozzles 5 are equidistantly spaced along the top of the liquid collecting ring 4, and all six nozzles 5 are inclined upwards towards the center to ensure the sprayed liquid is directed upwards and converges towards the center. One outlet of the gas distribution assembly 2 extends into the upper interior of the vessel body 1, above the nozzles 5, and sprays air downwards. The other outlet of the gas distribution assembly 2 is located below the interior of the vessel body 1 and has three gas distribution sections 27. Each stirring blade 35 of the stirrer 3 has a gas distribution section 27 below it. A catalyst is placed inside the vessel body 1. The desulfurization waste liquid is drawn into the collection ring 4 through the liquid inlet assembly 6 and sprayed out by six nozzles 5. Since all six nozzles 5 are oriented towards the center and tilted upwards, the sprayed desulfurization waste liquid collides and disperses in the central area above the nozzles 5, and mixes thoroughly with the air sprayed from the upper outlet end of the gas distribution assembly 2 before falling into the lower part of the vessel body 1. The agitator 3 mixes the catalyst, desulfurization waste liquid, and air. During the agitation process, the lower outlet end of the gas distribution assembly 2 provides air from the lower part of the vessel body 1, mixing with the catalyst and desulfurization waste liquid. Furthermore, since each stirring blade 35 is located above a layer of gas distribution section 27, the air supplied from the gas distribution section 27 is dispersed by the stirring blades 35 as soon as it enters the desulfurization waste liquid, further improving mixing efficiency and uniformity, and enhancing the catalytic oxidation effect and efficiency.

[0054] The gas distribution assembly 2 includes an oxidation blower 21, a gas booster pump 22, a gas distribution plate 23, a first gas distribution pipe 24, a second gas distribution pipe 25, a gas collecting seat 26, and a gas distribution section 27. The outlet of the oxidation blower 21 is connected to the first gas distribution pipe 24 and the second gas distribution pipe 25. The first gas distribution pipe 24 is equipped with a gas booster pump 22. The gas distribution plate 23 is fixed to the inner top wall of the vessel body 1. The outlet end of the first gas distribution pipe 24 is connected to the gas distribution plate 23. The bottom of the gas distribution plate 23 has multiple radially distributed first gas outlet holes 29. The middle part of the gas distribution plate 23 has a perforation 28. The gas collecting seat 26 is fixed to the inner bottom wall of the vessel body 1. The inner side wall of the gas collecting seat 26 is fixedly connected to multiple gas distribution sections 27. Each gas distribution section 27 includes multiple gas distribution sections 27 that are equidistantly distributed along the circumference of the gas collecting seat 26. The top of each gas distribution section 27 has a linearly distributed second gas outlet hole 210. Air is distributed through the oxidation blower 21 and the first air distribution pipe 24 to the air distribution plate 23. The gas booster pump 22 ensures that the air is ejected at high pressure from the air distribution plate 23, allowing for better mixing with the high-pressure ejected desulfurization waste liquid. Air is then sent to the gas collection seat 26 through the second air distribution pipe 25. The air is further distributed by the layered air distribution section 27, thus achieving different air distribution methods at both the top and bottom, greatly improving the mixing of air with the desulfurization waste liquid and catalyst. The radially distributed first air outlet 29 combined with the linearly distributed second air outlet 210 ensures more widespread and uniform air distribution at their respective locations.

[0055] The agitator 3 includes a motor 31, a stirring shaft 32, a first spiral blade 33, a second spiral blade 34, and stirring blades 35. The motor 31 is fixed to the top wall of the vessel body 1, and the stirring shaft 32 is fixed to the bottom end of the motor 31. Three stirring blades 35 are fixed axially at intervals on the lower part of the stirring shaft 32. Each stirring blade 35 is located above a gas distribution section 27. The first spiral blade is fixed on the stirring shaft 32 between the upper and middle stirring blades 35, and the second spiral blade is fixed on the stirring shaft 32 between the lower and middle stirring blades 35. The spiral directions of the first and second spiral blades are opposite. The motor 31 drives the stirring shaft 32 to rotate, which in turn drives the stirring blades 35 to rotate, and simultaneously drives the first spiral blade 33 and the second spiral blade 34 to rotate. Since the spiral directions of the first spiral blade 33 and the second spiral blade 34 are opposite, the material liquid can be pushed towards the center or away from each other while stirring. The vertically arranged first helical blade 33, the second helical blade 34, and the horizontally arranged stirring blade 35 can better achieve the mixing efficiency and effect of catalyst, desulfurization waste liquid, and air, thereby improving the efficiency and effect of catalytic oxidation.

[0056] Each of the first helical blade 33 and the second helical blade 34 is provided with a sleeve 36, which encloses the first helical blade 33 and the second helical blade 34 respectively, and the sleeves 36 are fixed to the air distribution section 27. Through the cooperation of the sleeves 36 with the first helical blade 33 and the second helical blade 34, the effect of pushing the liquid is enhanced, and the mixing efficiency and effect are further improved.

[0057] The liquid inlet assembly 6 includes an inlet pump 61, an inlet pipe 62, and a liquid booster pump 63. One end of the inlet pipe 62 is connected to the inlet pump 61, and the other end is connected to the collection ring 4. The liquid booster pump 63 is installed on the inlet pipe 62. The desulfurization waste liquid is pumped to the inlet pipe 62 by the inlet pump 61 and then sent to the collection ring 4 by the inlet pipe 62. The liquid booster pump 63 causes the desulfurization waste liquid to be sprayed out at high pressure, which increases the impact force and makes the desulfurization waste liquid dispersed more widely and finely, and better mixes with the sprayed air.

[0058] The oxidation reactor 100 also includes a second reflux pipe 7 and a reflux pump 8. One end of the second reflux pipe 7 is fixedly connected to the bottom of the reactor body 1, and the other end of the second reflux pipe 7 is fixedly connected to the liquid inlet pipe 62, and is located between the liquid booster pump 63 and the liquid inlet pump 61. The arrangement of the reflux pump 8 and the second reflux pipe 7 enables the recycling of desulfurization wastewater, making the catalytic oxidation more thorough.

[0059] The oxidation reactor 100 also includes a liquid flow meter 9, a gas flow meter 10, and a control cabinet 11. A gas flow meter 10 is installed on the first gas distribution pipe 24, and a liquid flow meter 9 is installed on the liquid inlet pipe 62. The liquid flow meter 9, gas flow meter 10, reflux pump 8, liquid booster pump 63, liquid inlet pump 61, gas booster pump 22, oxidation blower 21, and stirrer 3 are all electrically connected to the control cabinet 11. The flow rates of the liquid and gas inlet can be controlled by the liquid flow meter 9 and gas flow meter 10, thereby improving the catalytic oxidation effect.

[0060] It also includes a first condenser 900, a second condenser 1100, and a scrubbing tower 1000. The first condenser 900 is connected to the exhaust port of the oxidation kettle 100, the exhaust port of the first condenser 900 is connected to the scrubbing tower 1000, and the second condenser 1100 is connected to the steam exhaust port of the vacuum evaporation kettle.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A waste liquid evaporation and salt separation resource utilization system, characterized in that: It includes an oxidation reactor, a decolorization tower, a first centrifuge, a vacuum evaporation reactor, a second centrifuge, a crystallization reactor, and a third centrifuge connected in sequence; The outlet of the third centrifuge is connected to the vacuum evaporator through the first reflux pipe; The oxidation reactor includes a reactor body, a gas distribution assembly, a stirrer, a liquid collection ring, and a liquid inlet assembly; A stirrer is fixed to the top of the vessel body, and the stirring end of the stirrer extends into the interior of the vessel body. The liquid collecting ring is disposed inside the vessel body, and the liquid outlet end of the liquid inlet assembly is connected to the liquid collecting ring. Multiple nozzles are equidistantly connected to the top of the liquid collecting ring along the circumference, and all of the multiple nozzles are inclined upward toward the center so that the sprayed liquid is upward and converges toward the center. One of the air outlets of the air distribution assembly extends to the upper part of the interior of the vessel and is located above the nozzle, spraying air downwards in a jet manner. The other air outlet of the air distribution assembly is located below the interior of the vessel and has multiple air distribution sections. Each stirring blade of the stirrer has a layer of the air distribution section below it. The gas distribution assembly includes an oxidation fan, a gas booster pump, a gas distribution disc, a first gas distribution pipe, a second gas distribution pipe, a gas collection seat, and a gas distribution section; The outlet of the oxidation blower is connected to a first air distribution pipe and a second air distribution pipe. A gas booster pump is installed on the first gas distribution pipe, the gas distribution plate is fixed to the top wall of the vessel body, the gas outlet end of the first gas distribution pipe is connected to the gas distribution plate, the bottom of the gas distribution plate is provided with a plurality of radially distributed first gas outlet holes, and the middle of the gas distribution plate is provided with a perforation. The gas collecting seat is fixed to the bottom wall of the vessel body. The inner side wall of the gas collecting seat is fixedly connected to multiple gas distribution sections. Each gas distribution section includes multiple gas distribution sections that are equally spaced along the circumference of the gas collecting seat. The top of each gas distribution section is provided with a second gas outlet hole that is linearly distributed. The stirrer includes a motor, a stirring shaft, a first spiral blade, a second spiral blade, and stirring blades; The motor is fixed to the top wall of the vessel, and a stirring shaft is fixed to the bottom of the motor. Three stirring blades are fixed at axial intervals on the lower part of the stirring shaft, and each stirring blade is located above the first layer of the gas distribution section. A first helical blade is fixed on the stirring shaft between the upper and middle stirring blades, and a second helical blade is fixed on the stirring shaft between the lower and middle stirring blades. The first and second helical blades have opposite helical directions. A sleeve is provided at both the first and second helical blades, and the two sleeves respectively surround the first and second helical blades. The sleeves are fixed to the air distribution section. The oxidation reactor also includes a second reflux pipe and a reflux pump; One end of the second reflux pipe is fixedly connected to the bottom of the vessel body, and the other end of the second reflux pipe is fixedly connected to the liquid inlet assembly.

2. The waste liquid evaporation and salt desalination resource utilization system according to claim 1, characterized in that: The liquid inlet assembly includes a liquid inlet pump, a liquid inlet pipe, and a liquid booster pump; One end of the inlet pipe is connected to the inlet pump, and the other end of the inlet pipe is connected to the liquid collection ring. A liquid booster pump is provided on the inlet pipe.

3. The waste liquid evaporation and salt desalination resource utilization system according to claim 2, characterized in that: The other end of the second return pipe is fixedly connected to the inlet pipe and is located between the liquid booster pump and the inlet pump.

4. The waste liquid evaporation and salt desalination resource utilization system according to claim 3, characterized in that: The oxidation reactor also includes a liquid flow meter, a gas flow meter, and a control cabinet; A gas flow meter is installed on the first gas distribution pipe, and a liquid flow meter is installed on the liquid inlet pipe; The liquid flow meter, gas flow meter, reflux pump, liquid booster pump, inlet pump, gas booster pump, oxidation fan, and agitator are all electrically connected to the control cabinet. The waste liquid evaporation and desalination resource utilization system also includes a first condenser, a second condenser, and a scrubbing tower; The first condenser is connected to the exhaust port of the oxidation vessel, the exhaust port of the first condenser is connected to the washing tower, and the second condenser is connected to the steam discharge port of the vacuum evaporation vessel.

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