Pesticide production wastewater treatment equipment and method

Abstract

The invention relates to the field of wastewater treatment of organic chemical industry production and environmental protection, and provides pesticide production wastewater treatment equipment and method.The pesticide production wastewater treatment equipment comprises a pretreatment system used for adjusting the pH value of a wastewater stock solution, and a post-treatment system used for conducting filtration, catalyst recovery and deamination separation treatment on oxidized wastewater; the oxidation system comprises a three-stage heat exchanger, a heat-conducting oil heater and a vertical oxidation tower; the stock solution with the adjusted pH is preheated through a three-stage heat exchanger, the preheated stock solution is heated through a heat conduction oil heater and then introduced into a vertical oxidation tower to be oxidized, the oxidized stock solution carries oxidation heat and returns to the three-stage heat exchanger to exchange heat with the stock solution so as to preheat the stock solution, and the heat conduction oil heater conducts temperature compensation on the stock solution in the initial stage. The oxidation tower decomposes macromolecular substances into micromolecular substances, oxidizes organic nitrogen into inorganic nitrogen, and separates the inorganic nitrogen in an ammonia molecule form through steam stripping; chemical heat in the reaction process is recycled through heat exchange, and energy is saved.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment in organic chemical production and environmental protection, in particular to a pesticide production wastewater treatment device and method. Background Art

[0002] The raw materials, intermediates and products of pesticide production are mostly toxic and harmful complex chemicals, some of which are highly toxic. The wastewater discharged by them also contains toxic components, and the composition is complex, including high concentrations of salt and organic nitrogen, which are high-molecular substances that are difficult to biodegrade. COD is as high as tens of thousands of mg / m 3 TN is also several thousand mg / m 3 . This type of wastewater cannot be directly treated biochemically, and must be pretreated effectively to decompose the macromolecular substances, separate ammonia nitrogen and salt, and reduce its toxicity. Chemical oxidation methods are generally used, such as Fenton reagent oxidation, microelectrolysis, chlorination, etc. After oxidation, the macromolecular substances are partially or completely decomposed into small molecular substances, and organic nitrogen becomes ammonia nitrogen, which can be separated by stripping or steam stripping, and the salt can be separated by evaporation and crystallization. The above chemical oxidation methods all have the problems of low oxidation efficiency, incomplete oxidation, high oxidant consumption, and high cost, and some substances cannot be decomposed, which brings limitations to their application; in addition, the existing method is to directly use a heating device to heat the stock solution, and the heat generated during the oxidation process is also directly discharged into the environment, and the treatment cost is high; how to use low-cost common oxidants to efficiently oxidize and decompose wastewater and improve the removal effect of small molecular solid particles and ammonia nitrogen in wastewater is a research direction in this field. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a pesticide production wastewater treatment equipment and method that can recycle oxidation heat, improve the removal of small molecular solid particles and ammonia nitrogen in wastewater, reduce energy loss and treatment costs, and improve oxidation decomposition efficiency.

[0004] The technical scheme of the present invention is: a pesticide production wastewater treatment equipment, including a pre-treatment system, an oxidation system and a post-treatment system, the pre-treatment system is used to adjust the pH value of the wastewater raw liquid, the post-treatment system is used to filter the oxidized wastewater, recover the catalyst and perform ammonia separation treatment, the oxidation system includes a three-stage heat exchanger, a thermal oil heater and a vertical oxidation tower, the raw liquid after pH adjustment is preheated by the three-stage heat exchanger, the preheated raw liquid is heated by the thermal oil heater and then passed into the vertical oxidation tower for oxidation, the oxidized raw liquid carries the oxidation heat back to the three-stage heat exchanger to exchange heat with the raw liquid to preheat the raw liquid, and the thermal oil heater performs temperature compensation on the raw liquid in the initial stage; The post-treatment system includes a cooler, a gas-liquid separation tank, an oxidizing liquid storage tank and an ion exchange resin adsorption tank. The oxidized raw liquid is transported to the cooler through a pipeline for cooling. The cooler is connected to the gas-liquid separation tank through a pipeline. The pressure relief tank is connected to the oxidizing liquid storage tank through an oxidizing liquid pump. The oxidizing liquid storage tank enters the ion exchange resin adsorption tank after passing through a secondary membrane separator. A membrane feed pump is provided between the oxidizing liquid storage tank and the secondary membrane separator. The raw liquid enters the ammonia separation system after catalyst adsorption recovery in the ion exchange resin adsorption tank. After the free ammonia is separated by a steam stripping device, the raw liquid enters the desalination and biochemical process for subsequent treatment.

[0005] Preferably, the heat generated during the oxidation reaction in the vertical oxidation tower is the oxidation heat described in the present invention. The vertical oxidation tower is a pressure vessel with a height-to-diameter ratio of 10-20, which can withstand a high temperature of less than 300 degrees and a pressure of 8MPa; it is made of corrosion-resistant materials, and SS316L stainless steel, nickel-based alloy C-276, C-625 or titanium alloy are selected according to the concentration of chloride ions in the wastewater; when the wastewater stock enters the vertical oxidation tower, the catalyst and oxidant are mixed in advance, and after being pressurized by a high-pressure pump and heated by a heat exchanger and a thermal oil heater, it enters from the lower part of the vertical oxidation tower and flows slowly upward in sequence; under the action of the catalyst, the oxidant gradually oxidizes and decomposes the polymer substances in the wastewater; the catalyst is a soluble chemical substance, which is added to the wastewater in the pre-treatment system and mixed evenly, participates in promoting chemical decomposition in the vertical oxidation tower, is not decomposed itself, and is adsorbed by the resin in the post-treatment system for recovery.

[0006] Furthermore, the thermal oil heater includes a thermal oil heat exchanger, a thermal oil furnace and a thermal oil circulation pump. The outlet of the thermal oil heat exchanger is connected to the inlet of the thermal oil furnace through a pipeline. Two thermal oil circulation pumps in parallel are arranged on the pipeline. The outlet of the thermal oil furnace is connected to the inlet of the thermal oil heat exchanger through a pipeline. The thermal oil heat exchanger is used to heat the stock solution. The heating furnace heats the thermal oil and pumps the heated thermal oil from the bottom into the thermal oil heat exchanger through the thermal oil circulation pump. The reciprocating heat delivery ensures that the temperature of the stock solution entering the vertical oxidation tower is the optimal reaction temperature.

[0007] Furthermore, temperature transmitters are provided at the inlet and outlet of the thermal oil heat exchanger and the thermal oil furnace; the thermal oil heat exchanger is vertically arranged, and the thermal oil enters from the bottom and exits from the top.

[0008] Furthermore, the top of the vertical oxidation tower is connected to the pressure relief tank through a pipeline, and a safety valve and an alarm are provided on the pipeline; a plurality of temperature transmitters and pressure transmitters are provided at different elevations of the side wall and the top of the vertical oxidation tower to monitor the real-time temperature and pressure of the medium. Preferably, the oxidation and decomposition process of the polymer substance releases heat, and the temperature and pressure of the medium will increase during the reaction process; a plurality of temperature transmitters and pressure transmitters are provided at different elevations of the side wall and the top of the reaction tower to monitor the real-time temperature and pressure of the medium, facilitate regulation, prevent instantaneous over-temperature and over-pressure, and avoid the occurrence of safety accidents.

[0009] Furthermore, a catalyst and an oxidant are added to the pH-adjusted stock solution before entering the tertiary heat exchanger or the thermal oil heater; the oxidant is compressed air, pure oxygen or ozone.

[0010] Furthermore, the pretreatment system includes a raw liquid pool, a pH adjustment tank and a liquid storage tank. The raw liquid pool is connected to the pH adjustment tank through a pipeline. The pipeline is provided with a raw liquid pump, a flow meter, a flow regulating valve, a catalyst addition pipe and a dilute acid addition pipe. The pH adjustment tank is connected to the liquid storage tank through a regulating liquid pump. An ultrafiltration system is provided between the regulating liquid pump and the liquid storage tank. The liquid storage tank is connected to the oxidation system through a high-pressure pump; the raw liquid pump, the regulating liquid pump and the high-pressure pump are all configured as parallel double pumps.

[0011] Furthermore, the cooler is of shell-and-tube type, and the temperature of the oxidizing liquid is further reduced to room temperature by circulating cooling water, and enters the gas-liquid separation tank, at which point the system temperature and pressure are converted to room temperature and pressure; a wire mesh demister is installed at the upper part of the gas-liquid separation tank, and the gas is discharged from the upper part to the exhaust gas treatment system, and the liquid is pumped into the oxidizing liquid storage tank; the escaped gas at the upper part of the oxidizing liquid storage tank is also discharged to the exhaust gas treatment system.

[0012] Furthermore, a resin ion exchange adsorption column is provided in the ion exchange resin adsorption tank to adsorb and retain the catalyst in the oxidizing liquid, recover it through backwashing and regeneration, reuse it after treatment, and discharge the filtrate to the subsequent ammonia separation system.

[0013] Furthermore, an ammonia separation preheater is provided before the stripping device. The oxidizing liquid is first heated by the ammonia separation preheater, and then enters from the upper part of the stripping tower, countercurrently contacts with the steam entering from the lower part, and the free ammonia is taken out by the steam, discharged from the top, and enters the subsequent condensation and absorption device for ammonia water recovery; the wastewater after ammonia separation returns to the ammonia separation preheater to transfer heat to the oxidizing liquid that has just entered, and the wastewater after heat exchange enters the subsequent desalination and biochemical treatment system for further treatment and then meets the discharge standards; thereby improving the recovery efficiency of ammonia and reducing energy loss. Preferably, the stripping device is a stripping tower, and steam is introduced from the lower end of the stripping tower to improve the recovery effect of ammonia.

[0014] A method for treating pesticide production wastewater, using the above-mentioned pesticide production wastewater treatment equipment to treat wastewater, comprises the following steps: S1, the wastewater in the stock liquid pool is transported to the pH adjustment tank through the stock liquid pump, the pH adjuster and catalyst are added to adjust the pH value and filtered, and the filtrate is transported to the liquid storage tank for storage and standby use; S2, the filtrate in the S1 liquid storage tank is transported to the oxidation tank for oxidation, and the oxidant and the filtrate are transported to the oxidation tank together; S3, the filtrate is heat-exchanged through the three-stage heat exchanger before entering the oxidation tank, and then the filtrate containing the oxidant is heated by the thermal oil heater, and then enters the oxidation tank, where the filtrate is oxidized to generate heat, and the oxidized solution is again transported to the three-stage heat exchanger to heat the filtrate that has just entered, so as to preheat the filtrate that has just entered and reuse the oxidation heat, thereby reducing the energy loss in the process of heating the filtrate; S4, the solution after heat exchange is transported to the circulating cooler for cooling, and the pressure is released by the gas-liquid separation tank. After the pressure is released, it is pumped into the oxidation liquid storage tank, and the catalyst is recovered after filtration separation and ion exchange resin adsorption, and then the ammonia is separated by the steam stripping device, and finally enters the desalination and biochemical process for subsequent treatment.

[0015] The present invention has the following beneficial effects: 1. After the wastewater is oxidized by this device, the high-molecular toxic components are oxidized and decomposed into low-molecular or non-toxic substances or small molecules; organic nitrogen is oxidized into ammoniacal nitrogen, which can be separated by stripping or steam stripping; organic chlorine, organic sulfur, etc. are oxidized into inorganic salts and separated by evaporation and crystallization to provide water quality assurance for subsequent biochemical treatment processes; ammonia is recovered through the ammonia recovery system, and the ammonia separation preheater is preheated by the waste heat of the stripping tower during the recovery process, which improves the ammonia recovery efficiency and reduces energy loss and cost.

[0016] 2. The oxidant required by the present invention is oxygen, which can be conventional compressed air, pure oxygen or ozone, and the oxidation cost is greatly reduced.

[0017] 3. The catalyst is soluble in water and can be mixed evenly with wastewater. It has a good catalytic effect and is not oxidized itself. It can be recycled and reused without increasing operating costs.

[0018] 4. The chemical heat in the reaction process is recovered and utilized through heat exchange to heat the temperature of the liquid to be treated, thus saving energy and reducing operating costs.

[0019] 5. The thermal oil heater can heat the treated liquid evenly and prevent local excessive temperature from causing vaporization.

[0020] The detailed structure of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the oxidation system structure of the present invention; Figure 2 It is a schematic diagram of the structure of the pre-treatment system in the present invention; Figure 3 It is a schematic diagram of the structure of the post-processing system in the present invention; 1-pretreatment system, 2-three-stage heat exchanger, 3-thermal oil heat exchanger, 4-thermal oil furnace, 5-thermal oil circulation pump, 6-vertical oxidation tower, 7-pressure relief tank, 8-waste gas treatment system, 9-pressure relief waste liquid, 10-post-treatment system, 11-oxidant, 12-temperature transmitter, 13-pressure transmitter, 14-safety valve, 15-stock liquid tank, 16-stock liquid pump, 17-flow meter, 18-flow regulating valve, 19-catalyst addition pipe, 20-dilute acid addition pipe, 21-pipe mixer, 22-pH adjustment tank, 23-agitator, 24-adjusting liquid pump, 25-diaphragm ultrafiltration system, 26-liquid storage tank, 27-high-pressure pump, 28-oxidation system, 29-liquid level meter, 30-oxidation liquid, 31-circulating cooling water, 32-cooler, 33-cooling return pipe, 34-gas-liquid separation tank, 35-oxidation liquid pump, 36-oxidation liquid storage tank, 37-membrane feed pump, 38-secondary membrane separator, 39-ion exchange resin adsorption tank, 40-catalyst recovery, 41-ammonia separation preheater, 42-stripping tower, 43-deammoniation water recovery system, 44-steam, 45-subsequent desalination and biochemical treatment system. DETAILED DESCRIPTION Embodiment 1

[0022] As shown in the attached drawings: a pesticide production wastewater treatment equipment, including a pre-treatment system 1, an oxidation system 28 and a post-treatment system 10, the pre-treatment system 1 is used to adjust the pH value of the wastewater raw liquid, the post-treatment system 10 is used to filter the oxidized wastewater, recover the catalyst 40 and remove ammonia separation treatment, the oxidation system 28 includes a three-stage heat exchanger 2, a thermal oil heater and a vertical oxidation tower 6, the raw liquid after pH adjustment is preheated by the three-stage heat exchanger 2, the preheated raw liquid is heated by the thermal oil heater and then passed into the vertical oxidation tower 6 for oxidation, the oxidized raw liquid carries the oxidation heat back to the three-stage heat exchanger 2 to exchange heat with the raw liquid to preheat the raw liquid, and the thermal oil heater performs temperature compensation on the raw liquid in the initial stage.

[0023] Preferably, the vertical oxidation tower 6 is a pressure vessel with a height-to-diameter ratio of 10-20, which can withstand high temperatures within 300 degrees and a pressure of 8 MPa; it is made of corrosion-resistant materials, and SS316L stainless steel, nickel-based alloy C-276, C-625 or titanium alloy are selected according to the concentration of chloride ions in the wastewater; when the wastewater raw liquid enters the vertical oxidation tower 6, the catalyst and oxidant 11 are mixed in advance, and after being pressurized by the high-pressure pump 27 and heated by the heat exchanger and the thermal oil heater, it enters from the lower part of the vertical oxidation tower 6 and flows slowly upward in sequence; under the action of the catalyst, the oxidant 11 gradually oxidizes and decomposes the high-molecular substances in the wastewater; the catalyst is a soluble chemical substance, which is added to the wastewater in the pre-treatment system 1 and mixed evenly, participates in promoting chemical decomposition in the vertical oxidation tower 6, is not decomposed itself, and is adsorbed by the resin in the post-treatment system 10 for recovery.

[0024] The thermal oil heater includes a thermal oil heat exchanger 3, a thermal oil furnace 4 and a thermal oil circulation pump 5. The outlet of the thermal oil heat exchanger 3 is connected to the inlet of the thermal oil furnace 4 through a pipeline. Two thermal oil circulation pumps 5 are arranged in parallel on the pipeline. The outlet of the thermal oil furnace 4 is connected to the inlet of the thermal oil heat exchanger 3 through a pipeline. The thermal oil heat exchanger 3 is used to heat the stock solution. The heating furnace heats the thermal oil and pumps the heated thermal oil from the bottom into the thermal oil heat exchanger 3 through the thermal oil circulation pump 5. The reciprocating heat delivery ensures that the temperature of the stock solution entering the vertical oxidation tower 6 is the optimal reaction temperature.

[0025] Preferably, temperature transmitters 12 are provided at the inlet and outlet of the thermal oil heat exchanger 3 and the thermal oil furnace 4; the thermal oil heat exchanger 3 is vertically arranged, and the thermal oil enters from the bottom and exits from the top.

[0026] In the embodiment, the top of the vertical oxidation tower 6 is connected to the pressure relief tank 7 through a pipeline, and a safety valve 14 and an alarm are provided on the pipeline; a plurality of temperature transmitters 12 and pressure transmitters 13 are respectively provided at different elevations of the side wall and the top of the vertical oxidation tower 6 to monitor the real-time temperature and pressure of the medium; the pressure relief waste liquid 9 in the pressure relief tank 7 and the pressure relief waste liquid 9 in the vertical oxidation tower 6 are both returned to the stock liquid pool 15. Preferably, the oxidation and decomposition process of the polymer substance releases heat, and the temperature and pressure of the medium will increase during the reaction process; a plurality of temperature transmitters 12 and pressure transmitters 13 are respectively provided at different elevations of the side wall and the top of the reaction tower to monitor the real-time temperature and pressure of the medium, facilitate regulation, prevent instantaneous over-temperature and over-pressure, and avoid the occurrence of safety accidents.

[0027] In the embodiment, the oxidant 11 is added to the stock solution after pH adjustment before entering the tertiary heat exchanger 2; the oxidant 11 is compressed air, pure oxygen or ozone; in this embodiment, the oxidant 11 is oxygen.

[0028] In the embodiment, the pretreatment system 1 includes a raw liquid pool 15, a pH adjustment tank 22 and a liquid storage tank 26. The raw liquid pool 15 is connected to the pH adjustment tank 22 through a pipeline. The pH adjustment tank 22 is provided with an agitator 23 to improve the pH value adjustment efficiency. The pipeline is provided with a raw liquid pump 16, a flow meter 17, a flow control valve 18, a catalyst addition pipe 19 and a dilute acid addition pipe 20. A pipeline mixer 21 is provided between the dilute acid addition pipe 20 and the pH adjustment tank 22 to improve the mixing uniformity of the raw liquid and the dilute acid; the pH adjustment tank 22 is connected to the liquid storage tank 26 through a regulating liquid pump 24, and a diaphragm ultrafiltration system 25 is provided between the regulating liquid pump 24 and the liquid storage tank 26. The liquid storage tank 26 is connected to the oxidation system 28 through a high-pressure pump 27; the raw liquid pump 16, the regulating liquid pump 24 and the high-pressure pump 27 are all configured as parallel double pumps.

[0029] In the embodiment, the post-treatment system 10 includes a cooler 32, a gas-liquid separation tank 34, an oxidizing liquid storage tank 36 and an ion exchange resin adsorption tank 39. The oxidized raw liquid, i.e., the oxidizing liquid 30, is transported to the cooler 32 through a pipeline for cooling. The cooler 32 is connected to the gas-liquid separation tank 34 through a pipeline. The pressure relief tank is connected to the oxidizing liquid storage tank 36 through an oxidizing liquid pump 35. The oxidizing liquid storage tank 36 enters the ion exchange resin adsorption tank 39 after passing through the secondary membrane separator 38. A membrane feed pump 37 is provided between the oxidizing liquid storage tank 36 and the secondary membrane separator 38. After the raw liquid is adsorbed by the ion exchange resin adsorption tank 39, a catalyst recovery 40 is performed, and then ammonia separation is performed through a steam stripping tower 42, and finally the desalination and biochemical process is entered for subsequent treatment.

[0030] Preferably, an ammonia separation preheater 41 is provided before the stripping tower 42. The oxidizing liquid is first heated by the ammonia separation preheater, and then enters from the upper part of the stripping tower 42, and contacts with the steam 44 entering from the lower part in countercurrent. The free ammonia is carried out by the steam 44, discharged from the top, and enters the subsequent condensation and absorption device for ammonia water recovery; the wastewater after ammonia separation returns to the ammonia separation preheater to transfer heat to the oxidizing liquid that has just entered. After heat exchange, the wastewater enters the subsequent desalination and biochemical treatment system 45 for further treatment and meets the discharge standards.

[0031] More preferably, the ammonia separation system includes an ammonia separation preheater 41 and a stripping tower 42. The filtrate after adsorption enters from the lower end of the ammonia separation preheater 41, and after preheating, enters from the upper end of the ammonia separation preheater 41 to the upper part of the stripping tower 42. Steam 44 is introduced into the lower end of the stripping tower. The top of the stripping tower 42 is connected to the ammonia water recovery system 43 through a pipeline to recover ammonia. The liquid after ammonia removal enters the ammonia separation preheater 41 from the bottom of the stripping tower 42 and the heat carried by the liquid is used to preheat the filtrate just entering the ammonia separation preheater 41. Finally, the bottom of the ammonia separation preheater 41 is connected to the subsequent desalination and biochemical treatment system 45 through a pipeline, thereby improving the recovery efficiency of ammonia and reducing energy loss.

[0032] In this embodiment, the tops of the pH adjustment tank 22, the liquid storage tank 26, the pressure relief tank 7, the gas-liquid separation tank 34 and the oxidation liquid storage tank 36 are all provided with exhaust pipes, and the exhaust pipes are all connected to the exhaust gas treatment system 8 to avoid directly discharging the exhaust gas into the surrounding environment, which is beneficial to the improvement of environmental protection. The pH adjustment tank 22, the liquid storage tank 26 and the oxidation liquid storage tank 36 are all provided with liquid level meters 29.

[0033] In the embodiment, the cooler 32 is a shell-and-tube type, and the temperature of the oxidizing liquid 30 is further reduced to room temperature by circulating cooling water 31. The oxidizing liquid 30 enters the gas-liquid separation tank 34, and the system temperature and pressure are converted to room temperature and pressure. The cooling water in the cooler 32 is cooled by the cooling return pipe 33 and then refluxed; a wire mesh demister is installed at the upper part of the gas-liquid separation tank 34, and the gas is discharged from the upper part to the exhaust gas treatment system 8, and the liquid is pumped into the oxidizing liquid storage tank 36; the escaped gas at the upper part of the oxidizing liquid storage tank 36 is also discharged to the exhaust gas treatment system 8.

[0034] The ion exchange resin adsorption tank 39 is provided with a resin ion exchange adsorption column, which adsorbs and intercepts the catalyst in the oxidizing liquid 30, recovers it through backwashing and regeneration, and reuses it after treatment. The filtrate is discharged to the subsequent ammonia separation system for separation. Embodiment 2

[0035] A method for treating pesticide production wastewater, using the pesticide production wastewater treatment equipment of the above embodiment to treat the wastewater, comprises the following steps: S1, the wastewater in the stock liquid pool 15 is transported to the pH adjustment tank 22 through the stock liquid pump 16, the pH adjuster dilute acid and the catalyst are added and mixed through the pipeline mixer 21 and then enter the pH adjustment tank 22, the pH value is adjusted after stirring, the liquid after the pH value is adjusted is filtered through the membrane ultrafiltration system 25, and the filtrate is transported to the liquid storage tank 26 for storage and standby use; S2, the filtrate in the S1 liquid storage tank 26 is transported to the vertical oxidation tower 6 for oxidation, and the oxidant 11 is transported to the vertical oxidation tower 6 together with the filtrate; S3, the filtrate is heat-exchanged through the three-stage heat exchanger 2 before entering the vertical oxidation tower 6, and then the filtrate containing the oxidant 11 is heated and compensated by the thermal oil heater, and then enters the vertical oxidation tower 6, the filtrate is oxidized in the vertical oxidation tower 6 to generate heat, and the oxidized filtrate is again transported to the three-stage heat exchanger 2 to heat the filtrate that has just entered, so as to preheat the filtrate that has just entered and reuse the oxidation heat, thereby reducing the energy loss in the process of heating the filtrate; S4, the solution after heat exchange is transported to the circulating cooler 32 for cooling, and the gas-liquid separation tank 34 is used for pressure relief, and then the solution is pumped into the oxidation liquid storage tank 36, and solid-liquid separation is performed in the secondary membrane separator 38, and the filtrate is adsorbed by the ion exchange resin, and then the catalyst is recovered 40 and the ammonia separation system is used for subsequent treatment; Preferably, the waste gas in the entire reaction process is treated by a waste gas treatment system 8 to avoid direct discharge that affects the surrounding environment. The vertical oxidation tower 6 is provided with a safety valve 14, an alarm and a temperature transmitter 12 for monitoring the temperature of the oxidation tower. When the temperature and pressure in the tower are too high, the pressure can be relieved to the pressure relief tank 7 through the safety valve 14. The oxidizing liquid 30 after pressure relief and the oxidizing liquid 30 overflowing from the vertical oxidation tower 6 are returned to the raw liquid pool 15 to avoid direct discharge. Embodiment 3

[0036] Pesticide production wastewater from various places is collected in the stock liquid pool 15, and is lifted by the stock liquid pump 16 to enter the pH adjustment tank 22; before entering the tank, the catalyst and dilute acid are added and mixed by the pipeline mixer 21 respectively, and then the mixed liquid is transported to the mixing tank and stirred and mixed evenly by the stirrer 23. It is pressurized by the regulating liquid pump 24 and enters the membrane ultrafiltration system 25, and after the solid matter is removed, it enters the treatment liquid storage tank 26, and is pressurized by the high-pressure pump 27 and transported to the subsequent oxidation system 28.

[0037] Before entering the oxidation system 28, compressed air is added, and then the tertiary heat exchanger 2 and the thermal oil heater heat the filtrate. At the initial stage of system startup, there is no high-temperature oxidation liquid 30 to provide heat; at this time, the subsequent thermal oil heater is used to heat up. After the wastewater raw liquid is heated to the required temperature by the thermal oil heater, it enters the vertical oxidation tower 6 from the bottom of the vertical oxidation tower 6; catalytic oxidation reaction is carried out during the slow rising process; high-molecular toxic substances are oxidized and decomposed into low-molecular or small-molecular substances with low toxicity or non-toxicity, and inorganic nitrogen and inorganic sulfur are oxidized into ammonia nitrogen and inorganic salts.

[0038] Since the oxidation reaction process releases heat, the temperature of the reaction liquid further rises. After leaving the reactor, it returns to the previous three-stage heat exchanger 2 to transfer the heat to the subsequent oxidized liquid 30, and then enters the gas-liquid separation tank 34 after further cooling to room temperature through the cooler 32. The gas contains ammonia and various acidic components. The waste gas is sent to the waste gas treatment system 8 and is treated by acid washing, alkali washing and water washing before it meets the emission standards; the liquid is lifted by a pump and sent to the oxidation liquid storage tank 36, and then sent to the secondary membrane separator 38 through the membrane feed pump 37. After removing the solid matter generated in the oxidation process, it enters the ion exchange resin adsorption tank 39 for catalyst recovery 40. The catalyst recovered by backwashing and regeneration is reused after treatment, and the oxidation liquid 30 after the catalyst is added is discharged to the subsequent ammonia separation process for further treatment. Embodiment 4

[0039] When the concentration of pollutants in the wastewater is high enough, the reaction heat can maintain the heat required by the system, and the thermal oil heater can be disabled at this time; when the concentration of pollutants in the wastewater is higher, the reaction heat may exceed the heat required by the system, and the temperature of the medium in the vertical oxidation tower 6 will rise abnormally, and the pressure will also rise accordingly; when the pressure exceeds the set maximum value, the safety valve 14 at the top of the reaction tower will jump open, and part of the reaction medium will enter the pressure relief tank 7, and an alarm will be sounded at the same time to remind the operating personnel to make timely adjustments, reduce the amount of liquid inlet or adjust to reduce the concentration of organic matter so that the system can return to normal; the operation of other parts is the same as that of Example 3. Embodiment 5

[0040] When the concentration of organic matter in the wastewater is not high enough, the reaction heat is not enough to maintain the thermal balance of the system. At this time, the thermal oil heater needs to be turned on. The thermal oil furnace 4 first heats the thermal oil to a specified temperature, and then the heat is transferred to the treated liquid after heat exchange through the thermal oil heat exchanger 3, so that it enters the vertical oxidation tower 6 after heating to the required temperature; the thermal oil is circulated for heating and heat exchange; the system temperature is adjusted in real time by adjusting the thermal oil circulation flow and electric power; the temperature value of the inlet of the vertical oxidation tower 6 is linked to the adjustment mechanism; the operation of other parts is the same as that of Example 3.

[0041] After the wastewater is oxidized by the equipment in the present invention, the high-molecular toxic components are oxidized and decomposed into low-toxic or non-toxic low-molecular substances or small molecules; organic nitrogen is oxidized into ammoniacal nitrogen, which can be separated by methods such as stripping or steam stripping; the organic chlorine, organic sulfur, etc. contained are oxidized into inorganic salts, which are separated by evaporation and crystallization methods to provide water quality assurance for subsequent biochemical treatment processes. The oxidant 11 required by the present invention is oxygen, which can be conventional compressed air, pure oxygen or ozone, and the oxidation cost is greatly reduced. The catalyst is soluble in water, mixes evenly with the wastewater, has a good catalytic effect, and is not oxidized itself, can be recycled and reused, and does not increase operating costs. The chemical heat in the reaction process is recycled and utilized through heat exchange to heat the temperature of the liquid to be treated, saving energy and facilitating the reduction of operating costs. The thermal oil heater can heat the liquid to be treated evenly and prevent local excessive temperature from causing vaporization.

[0042] The above are preferred embodiments of the present invention and the technical principles used therein. For those skilled in the art, without departing from the spirit and scope of the present invention, any obvious changes such as equivalent transformation, simple replacement, etc. based on the technical solution of the present invention are within the scope of protection of the present invention.

Claims

1. A pesticide production wastewater treatment equipment, comprising a pre-treatment system, an oxidation system and a post-treatment system, wherein the pre-treatment system is used to adjust the pH value of the wastewater stock solution, and the post-treatment system is used to filter the oxidized wastewater, recover the catalyst and perform ammonia separation treatment, characterized in that: The oxidation system comprises a three-stage heat exchanger, a thermal oil heater and a vertical oxidation tower. The stock solution after pH adjustment is preheated by the three-stage heat exchanger. The preheated stock solution is heated by the thermal oil heater and then passed into the vertical oxidation tower for oxidation. The oxidized stock solution carries oxidation heat and returns to the three-stage heat exchanger to exchange heat with the stock solution to preheat the stock solution. In the initial stage, the thermal oil heater performs temperature compensation on the stock solution. The post-treatment system includes a cooler, a gas-liquid separation tank, an oxidizing liquid storage tank and an ion exchange resin adsorption tank. The oxidized raw liquid is transported to the cooler through a pipeline for cooling. The cooler is connected to the gas-liquid separation tank through a pipeline. The pressure relief tank is connected to the oxidizing liquid storage tank through an oxidizing liquid pump. The oxidizing liquid storage tank enters the ion exchange resin adsorption tank after passing through a secondary membrane separator. A membrane feed pump is provided between the oxidizing liquid storage tank and the secondary membrane separator. The raw liquid enters the ammonia separation system after catalyst adsorption recovery in the ion exchange resin adsorption tank. After the free ammonia is separated by a steam stripping device, the raw liquid enters the desalination and biochemical process for subsequent treatment.

2. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: The thermal oil heater comprises a thermal oil heat exchanger, a thermal oil furnace and a thermal oil circulation pump. The outlet of the thermal oil heat exchanger is connected to the inlet of the thermal oil furnace through a pipeline. Two thermal oil circulation pumps in parallel are arranged on the pipeline. The outlet of the thermal oil furnace is connected to the inlet of the thermal oil heat exchanger through a pipeline.

3. The pesticide production wastewater treatment equipment according to claim 2, characterized in that: The inlet and outlet of the thermal oil heat exchanger and the thermal oil furnace are both provided with temperature transmitters; the thermal oil heat exchanger is arranged vertically.

4. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: The top of the vertical oxidation tower is connected to the pressure relief tank through a pipeline, and a safety valve and an alarm are provided on the pipeline; a plurality of temperature transmitters and pressure transmitters are provided at different elevations of the side wall and the top of the vertical oxidation tower to monitor the real-time temperature and pressure of the medium.

5. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: The catalyst and oxidant are added to the pH-adjusted stock solution before entering the three-stage heat exchanger or the thermal oil heater; the oxidant is compressed air, pure oxygen or ozone.

6. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: The pretreatment system includes a raw liquid pool, a pH adjustment tank and a liquid storage tank. The raw liquid pool is connected to the pH adjustment tank through a pipeline. The pipeline is provided with a raw liquid pump, a flow meter, a flow regulating valve, a catalyst addition pipe and a dilute acid addition pipe. The pH adjustment tank is connected to the liquid storage tank through a regulating liquid pump. An ultrafiltration system is provided between the regulating liquid pump and the liquid storage tank. The liquid storage tank is connected to the oxidation system through a high-pressure pump. The raw liquid pump, the regulating liquid pump and the high-pressure pump are all configured as parallel double pumps.

7. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: The cooler is of shell-and-tube type, and the temperature of the oxidizing liquid is further reduced to room temperature by circulating cooling water, and enters the gas-liquid separation tank, at which point the system temperature and pressure are converted to room temperature and pressure; a wire mesh demister is installed at the upper part of the gas-liquid separation tank, and the gas is discharged from the upper part to the exhaust gas treatment system, and the liquid is pumped into the oxidizing liquid storage tank; the escaped gas at the upper part of the oxidizing liquid storage tank is also discharged to the exhaust gas treatment system.

8. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: The ion exchange resin adsorption tank is provided with a resin ion exchange adsorption column, which adsorbs and intercepts the catalyst in the oxidizing liquid, recovers it through backwashing regeneration, reuses it after treatment, and discharges the filtrate to the subsequent ammonia separation preheater.

9. The pesticide production wastewater treatment equipment according to claim 1, characterized in that: An ammonia separation preheater is provided before the stripping device. The oxidizing liquid is first heated by the ammonia separation preheater, and then enters from the upper part of the stripping tower, where it is countercurrently contacted with the steam entering from the lower part. The free ammonia is carried out by the steam, discharged from the top, and enters the subsequent condensation and absorption device for ammonia water recovery. The wastewater after ammonia separation returns to the ammonia separation preheater to transfer heat to the oxidizing liquid that has just entered. After heat exchange, the wastewater enters the subsequent desalination and biochemical treatment system for further treatment before meeting the discharge standards.

10. A method for treating pesticide production wastewater, using the pesticide production wastewater treatment equipment according to any one of claims 1 to 9 to treat the wastewater, characterized in that: The following steps are involved: S1, the wastewater in the stock liquid pool is transported to the pH adjustment tank through the stock liquid pump, the pH adjuster and catalyst are added to adjust the pH value and filtered, and the filtrate is transported to the liquid storage tank for storage and standby use; S2, the filtrate in the S1 liquid storage tank is transported to the oxidation tank for oxidation, and the oxidant and the filtrate are transported to the oxidation tank together; S3, the filtrate is heat exchanged through the three-stage heat exchanger before entering the oxidation tank, and then the filtrate containing the oxidant is heated by the thermal oil heater, and then enters the oxidation tank. The filtrate oxidized in the oxidation tank is transported to the three-stage heat exchanger to exchange heat with the filtrate that has just entered; S4, the solution after heat exchange is transported to the circulating cooler for cooling, and the pressure is released by the gas-liquid separation tank. After the pressure is released, it is pumped into the oxidation liquid storage tank, and the catalyst is recovered after filtration separation and ion exchange resin adsorption, and then the ammonia is separated by the steam stripping device, and finally enters the desalination and biochemical process for subsequent treatment.

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