CN106380021A - High-concentration organic wastewater wet oxidation treatment system and method - Google Patents

Abstract

The invention discloses a wet oxidation treatment system for high-concentration organic wastewater, which is integrated with devices such as oxygen production, pretreatment, heat conduction oil heating, wet oxidation treatment, cooling and depressurization, gas-liquid separation, and tail gas treatment. The invention also discloses a method for treating high-concentration organic waste water by using the system. Compared with the prior art, the system of the present invention is convenient for transportation and installation, and has good integration; the system fully recycles the heat after reaction through multi-stage heat exchangers to preheat waste water and oxygen, which can reduce operating costs; The oxygen device uses air as raw material to produce high-purity oxygen on site for wet oxidation reaction, which can improve the efficiency of pollutant removal; the wet oxidation reaction device adopts bimetallic composite material, and the catalyst box is installed inside the reaction device, which is beneficial to improve the efficiency of the reaction device. Corrosion resistance and lower reaction conditions; the system can discharge slag from the reaction device during operation, which is beneficial to reduce the risk of system fouling and blockage, and can be widely used in the treatment of high-concentration refractory organic wastewater.

Description

A wet oxidation treatment system and method for high-concentration organic wastewater

technical field

The invention belongs to the technical field of water treatment, in particular to a wet oxidation treatment system and method for high-concentration organic wastewater.

Background technique

In recent decades, with the rapid development of industrialization, environmental pollution has become increasingly serious, especially water pollution. In my country, water pollution mainly comes from difficult-to-treat industrial sewage, especially sewage from petroleum, chemical, pesticide and other industries, which has the characteristics of high concentration, complex composition, poisonous and harmful, and poor biodegradability, which makes the traditional biodegradation process suffer. serious challenge. In addition, the extensive application of membrane technology in recent years has led to the further concentration of high-concentration industrial wastewater, and the resulting concentrated solution is a greater threat to humans and the environment.

Wet oxidation method is an advanced oxidation treatment process proposed in the 1950s. Due to its excellent characteristics in the treatment of high-concentration, toxic and harmful organic wastewater, this process has attracted the attention of scientists from various countries. The wet oxidation process is a treatment process that oxidizes and decomposes macromolecular organic substances in wastewater into small molecular organic substances, CO ₂ and water and other small molecular inorganic substances under high temperature and high pressure conditions. The reaction effluent of high-concentration organic wastewater treated by this process can meet the general biological treatment requirements.

At present, there are a series of problems in the actual industrial application of wet oxidation technology: (1) The oxidant commonly used in the process is air, the oxygen content in the air is about 20%, and the rest is nitrogen that does not participate in the reaction, so a large flow of air needs to be delivered to the reaction Therefore, larger compressors are required, and the investment cost of equipment is high. At the same time, the oxidation effect is not as good as that of pure oxygen, which also has a negative impact on the cost of tail gas treatment; The treatment effect of refractory substances such as small molecule organic acids and small molecule organic acids is poor; the main research direction at present is to prepare catalysts with high activity and high stability to improve conversion efficiency, and the second is to combine effluent with MVR, biochemical and other methods. Secondary treatment of wet oxidation effluent; (3) Tail gas problem. The composition of tail gas discharged from the wet oxidation system varies with the change of treatment medium and process conditions. The main components are N ₂ and CO ₂ , which generally have pungent odor and volatile Reactive organic gases must be dealt with.

Contents of the invention

The purpose of the present invention is to provide a wet oxidation treatment system for high-concentration organic wastewater, which integrates the functions of oxygen production, wastewater pretreatment, heat conduction oil heating, wet oxidation treatment, cooling and depressurization, and tail gas adsorption.

The object of the present invention is also to provide a method for wet oxidation treatment of high-concentration organic wastewater by using the above-mentioned system.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

A wet oxidation treatment system for high-concentration organic wastewater, including a pretreatment device, a heat transfer oil heating device, and a reaction device sequentially connected through pipelines;

A first heat exchanger is provided between the pretreatment device and the heat transfer oil heating device, and communicated through the inner pipe of the first heat exchanger;

The inlet of the reaction device is provided with a bypass for feeding oxygen, which is directly connected to the oxygen generator; the bypass for feeding oxygen is provided with a second heat exchanger, and the inner pipe of the second heat exchanger makes the oxygen generator communicate with the inlet of the reaction device;

The outlet of the reaction device is sequentially connected to the second heat exchanger outer pipe, the first heat exchanger outer pipe, the cooling device, the decompression device, the gas-liquid separation device and the tail gas treatment device through pipelines.

Preferably, a bypass pipeline is provided between the inlet and outlet of the heat-conducting oil heating device, and a temperature sensor and an automatic valve are provided for temporarily stopping the operation of the heat-conducting oil heating device.

Preferably, a bypass pipe and an automatic valve for slag discharge of the reaction device are provided between the inlet of the reaction device and the inlet of the cooling device, and an automatic valve is provided between the inlet and outlet of the reaction device to temporarily avoid oxygen and waste water when the slag is discharged from the reaction device. Bypass pipes and automatic valves leading to the reaction device.

Preferably, the pretreatment device includes a waste water regulating tank, and the waste water regulating tank has two inlets, one is connected to the waste water pump and the waste water storage tank in sequence through a pipeline, and the other is connected to the automatic acid-base pump and the acid-base storage tank in sequence through a pipeline. tank; the outlet of the wastewater regulating tank is connected to a pipeline filter and a high-pressure plunger pump in turn, and the outlet pipe of the high-pressure plunger pump is connected to the inner pipe of the first heat exchanger.

Further preferably, the wastewater regulating tank is provided with an agitator and an online pH meter; a flow meter and a pipeline filter are provided on the pipeline in front of the high-pressure plunger pump.

Preferably, the heat-conducting oil heating device includes a heat-conducting oil pump, a heat-conducting oil heater, a third heat exchanger, and a heat-conducting oil high level tank, wherein the outlet of the heat-conducting oil pump is connected to the inlet of the heat-conducting oil heater, and the outlet of the heat-conducting oil heater It is connected with the inlet of the outer pipe of the third heat exchanger, the outlet of the outer pipe of the third heat exchanger returns to the inlet of the heat transfer oil pump, and the inlet and outlet of the heat transfer oil pump are connected in parallel with the heat transfer oil high level tank.

Preferably, a catalyst box is provided in the reaction device; the wall of the reaction device is composed of inner and outer layers, the outer layer is a pressure-bearing layer made of carbon steel or stainless steel, and the inner layer is a corrosion-resistant layer made of nickel-based alloy . The catalyst box can be filled with catalyst particles, which can effectively reduce reaction conditions and improve the removal rate of pollutants. The reaction device adopting bimetal composite material is beneficial to improve the corrosion resistance of the reaction device and reduce the reaction conditions.

Preferably, the oxygen generator includes an air compressor, a first pressure swing adsorption oxygen generator, a second pressure swing adsorption oxygen generator and an oxygen booster connected in sequence through pipelines, wherein the first pressure swing The inlets of the adsorption oxygen generator tank and the second PSA oxygen generator tank are respectively provided with bypasses for nitrogen discharge, and the inlet of the oxygen booster is provided with an oxygen vent bypass, which is automatically adjusted through valves and oxygen flowmeters. Wherein, the pressure swing adsorption oxygen generators are one for use and one for standby, one oxygen generator is used to prepare high-purity oxygen, and the other is used to discharge nitrogen for standby.

Preferably, the cooling device includes a clean water storage tank, a clean water pump and a cooler connected in sequence through pipelines, a bypass pipeline is provided between the outlet of the clean water pump and the outlet of the waste water adjustment tank, and the bypass pipeline is connected with A pickling device, the pickling device includes a dispensing tank and a chemical pump, and the system is pickled by switching valves when shutting down.

Preferably, the pressure reducing device is an automatic back pressure valve, the gas-liquid separation device is a gas-liquid separator, and the tail gas treatment device is an activated carbon adsorber. The activated carbon adsorber can effectively remove organic pollutants in the tail gas and realize pollution-free discharge.

The method of wet oxidation treatment of high-concentration organic wastewater by using the above system: when the system is running, the air enters the oxygen generator to produce high-purity oxygen, and then enters the reaction device after passing through the inner tube of the second heat exchanger. At the same time, the organic wastewater passes through the pre-treatment The treatment device, after passing through the inner tube of the first heat exchanger, is heated by the activated heat conduction oil heating device and then enters the reaction device. In the reaction device, high-purity oxygen and organic wastewater undergo wet oxidation reaction, and the high-temperature gas-liquid mixture after the reaction passes through The outlet of the reaction device enters the outer tube of the second heat exchanger and the outer tube of the first heat exchanger in turn, and exchanges heat with high-purity oxygen and organic waste water respectively, and then cools down through the cooling device, and then drops to At normal pressure, after depressurization, it enters the gas-liquid separation device. The gas enters the tail gas treatment device through the upper part of the gas-liquid separation device for treatment and then is discharged. The liquid is discharged from the outlet at the lower end of the gas-liquid separation device for centralized treatment.

When the above-mentioned wet oxidation treatment system for high-concentration organic wastewater is in operation, the heat after the reaction is recycled through the first heat exchanger and the second heat exchanger to preheat organic wastewater and high-purity oxygen, which can reduce system operating costs .

Preferably, in the reaction device, high-purity oxygen and organic waste water are reacted at 250-300° C. and 5-12 MPa for 1-2 hours. After the wet oxidation reaction, the refractory organic matter in the organic wastewater is decomposed into small molecular compounds, the phosphorus element in the organophosphorus compound is decomposed into inorganic phosphorus, and the nitrogen element in the organic nitrogen compound is decomposed into ammonia nitrogen, which improves the waste water while removing COD. Biodegradability.

Preferably, a bypass pipeline is provided between the inlet and outlet of the heat-conducting oil heating device, and a temperature sensor and an automatic valve are provided for temporarily stopping the work of the heat-conducting oil heating device. The heat conduction oil heating device is activated only when the temperature is high, otherwise it is directly connected through the bypass pipe.

Further preferably, the set temperature is 200-250°C.

When the system is running, the heat transfer oil pump and the heat transfer oil heater are first started, and the heat transfer oil enters the outer pipe inlet of the third heat exchanger after being heated, and then flows back to the heat transfer oil heating system from the outer pipe outlet of the third heat exchanger for recycling; Automatically adjust the power of the heat transfer oil heater according to the temperature at the outlet of the inner tube of the third heat exchanger, so that the temperature at the outlet of the inner tube of the third heat exchanger reaches the set temperature; if the temperature at the outlet of the inner tube of the first heat exchanger has reached the set temperature If the temperature is fixed, the heat transfer oil heater will stop working. In order to protect the safety of the heat transfer oil heating system, the heat transfer oil pump will always run.

Preferably, a bypass pipe and valve for slag discharge of the reaction device is provided between the inlet of the reaction device and the inlet of the cooling device, and a bypass for temporarily preventing oxygen and waste water from entering the reaction device is provided between the inlet and outlet of the reaction device. pipelines and valves. When it is necessary to discharge slag from the reaction device (6) during operation, the preheated waste water and oxygen do not enter the reaction device (6) but directly enter the follow-up equipment through valve switching, and at the same time, the reaction device (20) is used to make the reaction device (6) The pressure is reduced by 2 to 3 MPa, and the residue and part of the waste in the reaction device (6) enter the cooler (19) from the inlet of the reaction device (6), and then enter the gas-liquid separation after being depressurized by the pressure reducing device (20). The device (21) is discharged after separation and treatment.

In this way, the slag discharge of the reaction device during the operation of the system is realized, which is beneficial to reduce the risk of system fouling and blockage.

The oxygen generator realizes on-site oxygen generation. When the system is running, the air is pressurized to 0.4-0.8 MPa by the air compressor, enters the first pressure swing adsorption oxygen generator tank or the second pressure swing adsorption oxygen generator tank, and passes through the pressure swing adsorption tank. The adsorption oxygen tank can produce high-purity oxygen with a purity of more than 90%, and the oxygen flow can be automatically adjusted by venting the bypass; the high-purity oxygen can be pressurized by an oxygen booster to a reaction pressure of 5-12MPa, High-purity oxygen enters the inner tube of the second heat exchanger to exchange heat with the fluid after the reaction. After preheating, the temperature can reach 250-300°C, and then directly enters the reaction device. High-purity oxygen is produced through the oxygen generator and used for wet oxidation reaction, which can improve the efficiency of pollutant removal.

When the system is running, the organic wastewater is pre-stored in the wastewater storage tank. According to the actual pH of the organic wastewater, an appropriate amount of acid (such as HNO ₃ ) or lye (such as KOH) is pre-stored in the acid-base tank; turn on the wastewater pump and acid-base The pump adds the waste water and acid-base solution into the waste water adjustment tank, and at the same time starts the agitator and monitors the pH of the mixed material, so that the pH of the material is controlled at the set value (pH 6-9). The adjusted material passes through the pipeline filter to filter out particulate matter and enters the high-pressure plunger pump; after the pressurization and flow control of the high-pressure plunger pump, the material enters the inner tube of the first heat exchanger to exchange heat with the reacted fluid, as shown in the first If the outlet temperature of the inner tube of the first heat exchanger is lower than the predetermined value of 200-250°C, it will automatically enter the heat transfer oil heating device for further heating, and the material that meets the preheating condition will enter the reaction device; if the outlet temperature of the inner tube of the first heat exchanger reaches the predetermined value If the temperature is 200-250°C, it will directly enter the reaction device through the bypass pipe of the inlet and outlet of the heat transfer oil heating device. Through the organic wastewater pretreatment device, the functions of homogenization, pH adjustment and filtration of wastewater are realized. Moreover, KOH is used instead of NaOH as the alkaline pH regulator, because the solubility of the formed K ₂ CO ₃ is higher than that of Na ₂ CO ₃ , so it is more effective in slowing down the fouling of the wet oxidation treatment system.

When the system is running, the clean water of the cooling device is stored in the clean water storage tank, and the clean water pump is used to drive the water into the inlet of the outer pipe of the cooler, and the clean water at the outlet of the outer pipe of the cooler flows back to the clean water storage tank for recycling; the clean water in the tank is replaced regularly to ensure cooling Effect. After the high-temperature gas-liquid mixture reacted in the reaction device passes through the outer tube of the second heat exchanger, the outer tube of the first heat exchanger, and then is treated by the cooling device, the temperature of the gas-liquid mixture drops to 50-80°C.

After the system is shut down, in addition to the normal water flushing, it is also necessary to start the pickling device to pickle the system. Switch valves and pipelines, drive the medicine in the dispensing tank into the system through the medicine pump, pickle each device and pipeline, and remove scale.

Preferably, during pickling, the heat conduction oil heater is activated to keep the temperature in the reaction device at 60-80°C; the medicine in the dispensing tank used for pickling is 2% HNO ₃ ; the pickling duration is more than 8 hours.

Beneficial effects: Compared with the prior art, the wet oxidation treatment system of high-concentration organic wastewater of the present invention fully recycles the heat after reaction through multi-stage heat exchangers to preheat wastewater and high-purity oxygen, which can reduce system operation cost; high-purity oxygen is produced on-site by using air as a raw material through the oxygen production device, which can be used for wet oxidation reaction, which can improve the efficiency of pollutant removal; the wet oxidation reaction device adopts bimetallic composite material, and the catalyst box installed inside the reaction device can be used for Loading catalyst is beneficial to improve the corrosion resistance of the reaction device and reduce the reaction conditions; the system can discharge slagging from the reaction device during operation, which is beneficial to reduce the risk of system fouling and blockage; a waste water pretreatment device can realize waste water It has the functions of homogenization, pH adjustment and filtration; it is equipped with an activated carbon adsorber to remove organic pollutants in the tail gas; the system is easy to transport and install, has good integration, safe and reliable operation, and can be widely used in high-concentration refractory degradation Wet oxidation treatment of organic wastewater.

Description of drawings

Fig. 1 is the flow chart of the wet oxidation treatment system of high-concentration organic wastewater of the present invention;

Fig. 2 is a schematic structural diagram of a wet oxidation treatment system for high-concentration organic wastewater according to the present invention.

Among them: 1 air compressor, 2 first pressure swing adsorption oxygen tank, 3 second pressure swing adsorption oxygen tank, 4 oxygen booster, 5 second heat exchanger, 6 reaction device, 7 waste water storage tank, 8 Acid-base storage tank, 9 waste water pump, 10 automatic adjustment acid-base pump, 11 waste water adjustment tank, 12 pipeline filter, 13 high-pressure plunger pump, 14 first heat exchanger, 15 third heat exchanger, 16 heat conduction oil pump, 17 heat transfer oil heater, 18 heat transfer oil high level tank, 19 cooler, 20 pressure reduction device, 21 gas-liquid separation device, 22 tail gas treatment device, 23 medicine dispensing tank, 24 medicine pump, 25 clean water storage tank, 26 clean water pump.

detailed description

The wet oxidation treatment system and method for high-concentration organic wastewater of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Example 1

A wet oxidation treatment system for high-concentration organic wastewater as shown in Figure 1 includes a pretreatment device, a heat transfer oil heating device and a reaction device 6 connected in sequence by pipelines; between the pretreatment device and the heat transfer oil heating device A first heat exchanger 14 is provided, which communicates through the inner pipe of the first heat exchanger 14; the inlet of the reaction device 6 is provided with a bypass that feeds oxygen, directly connected to the oxygen generator; the bypass that feeds oxygen is provided with a second Two heat exchangers 5, the inlet of the oxygen generator and the reaction device 6 are communicated by the inner pipe of the second heat exchanger 5; The outer pipe of the device 14, the cooling device, the decompression device 20, the gas-liquid separation device 21 and the tail gas treatment device 22. In addition, a bypass pipe is provided between the inlet and outlet of the heat conduction oil heating device; a bypass pipe is provided between the inlet of the reaction device 6 and the inlet of the cooling device, and a bypass pipe is also provided between the inlet and outlet of the reaction device 6 .

As shown in Figure 2, the specific device and connection method of a wet oxidation treatment system for high-concentration organic wastewater are as follows:

1. Oxygen generating device: including an air compressor 1 , a first PSA oxygen generating tank 2 , a second PSA oxygen generating tank 3 and an oxygen booster 4 . Wherein, the outlet of the air compressor 1 is connected to the inlets of the first pressure swing adsorption oxygen generator tank 2 and the second pressure swing oxygen generator tank 3, and the outlets of the first pressure swing adsorption oxygen generator tank 2 and the second pressure swing oxygen generator tank 3 are connected with oxygen The inlet of the booster 4 is connected, the outlet of the oxygen booster 4 is connected with the inlet of the inner tube of the second heat exchanger 5 , and the outlet of the inner tube of the second heat exchanger 5 is connected with the inlet of the reaction device 6 . The inlets of the first pressure swing adsorption oxygen tank 2 and the second pressure swing oxygen tank 3 are respectively provided with nitrogen discharge bypasses, and the inlet of the oxygen booster 4 is provided with an oxygen venting bypass (with a venting bypass automatic regulating valve V1) And oxygen flow meter (FIC01). In addition, a pressure sensor (PIC02) and an automatic valve V2 are arranged on the outlet pipe of the inner pipe of the second heat exchanger 5 .

2. Pretreatment device: including wastewater regulating tank 11, wastewater pump 9, wastewater storage tank 7, automatic acid-base adjustment pump 10, acid-base storage tank 8, pipeline filter 12 and high-pressure plunger pump 13. The outlet of the waste water storage tank 7 is connected to the inlet of the waste water pump 9, the outlet of the acid-base tank 8 is connected to the inlet of the acid-base pump 10, and the outlet of the waste water pump 9 and the acid-base pump 10 are respectively connected to two inlets of the waste water regulating tank 11, and the waste water regulation The outlet of the tank 11 is connected to the inlet of the pipeline filter 12, the outlet of the pipeline filter 12 is connected to the inlet of the high-pressure plunger pump 13, and the outlet of the high-pressure plunger pump 13 is connected to the inlet of the inner tube of the first heat exchanger 14. The outlet of the tube in the heat exchanger 14 is connected with the inlet of the tube in the third heat exchanger 15, the outlet of the tube in the third heat exchanger 15 is connected with the inlet of the reaction device 6, and the inlet and outlet of the tube in the third heat exchanger 15 Set bypass and automatic valves V7, V8 and V9. The wastewater regulating tank 11 is provided with an agitator and an online pH meter (pHIC03), which can automatically adjust the start and stop of the acid-base pump 10 to control the wastewater to reach the set pH value. A flowmeter (FIC04) is installed on the pipeline before the high-pressure plunger pump 13 to automatically adjust the frequency converter frequency of the plunger pump to realize the automatic adjustment of the flow rate.

3. Heat conduction oil heating device: including heat conduction oil pump 16, heat conduction oil heater 17, third heat exchanger 15 and heat conduction oil head tank 18. The outlet of the heat transfer oil pump 16 is connected to the inlet of the heat transfer oil heater 17, the outlet of the heat transfer oil heater 17 is connected to the inlet of the third heat exchanger 15 outer pipe, and the outlet of the third heat exchanger 15 outer pipe returns to the outlet of the heat transfer oil pump 16. The inlet, the inlet and outlet of the heat transfer oil pump 16 are connected in parallel with the heat transfer oil head tank 18 . A temperature sensor TIC06 is provided on the inlet pipeline of the third heat exchanger 15 , and bypasses and valves V7 , V8 and V9 are provided at the inlet and outlet of the inner pipe of the third heat exchanger 15 . Temperature sensors (TIC06) and (TIC07) are respectively arranged on the inner tube inlet and outlet pipelines of the third heat exchanger 15, and the temperature sensor (TIC06) controls the opening and closing of the inlet and outlet valves V7, V8 and V9 of the third heat exchanger 15, The temperature sensor (TIC07) automatically controls the heating power of the heat conduction oil heater 17.

4. A catalyst box is arranged in the reaction device 6; the wall of the reaction device 6 is composed of inner and outer layers, the outer layer is a pressure-bearing layer made of carbon steel or stainless steel, and the inner layer is a corrosion-resistant layer made of nickel-based alloy. The outlet of the reaction device 6 is connected with the inlet of the second heat exchanger 5 outer tubes, the outlet of the second heat exchanger 5 outer tubes is connected with the first heat exchanger 14 outer tube inlets, and the outlet of the first heat exchanger 14 outer tubes Connect with the inner pipe inlet of the cooler 19, the inner pipe outlet of the cooler 19 is connected with the inlet of the pressure reducing device 20 automatic back pressure valve, the outlet of the automatic back pressure valve is connected with the inlet of the gas-liquid separator 21 gas-liquid separator, The gas outlet of the gas-liquid separator is connected to the inlet of the activated carbon adsorber of the tail gas treatment device 22, and the gas product after adsorption treatment is discharged to the outside, and the effluent of the gas-liquid separator is collected and disposed of; Road and related automatic valves V10, V13 and V12, the inlet of the reaction device 6 is connected with the inner pipe inlet of the cooler 19, and an automatic valve V12 is provided. The reaction device 6 is provided with a pressure sensor (TIC09), which is linked with the opening of the decompression device 20 to automatically control the system pressure.

5. Cooling device: including clean water storage tank 25, clean water pump 26 and cooler 19. Clean water is stored in the clean water storage tank 25, the outlet of the clean water storage tank 25 is connected to the inlet of the clean water pump 26, the outlet of the clean water pump 26 is connected to the outer pipe inlet of the cooler 19, and the outer pipe outlet of the cooler 19 is connected to the outlet of the clear water storage tank 25. Backwater connection. In addition, a bypass pipeline is provided between the outlet of the clean water pump 26 and the outlet of the waste water regulating tank 11, and the bypass pipeline is connected with a pickling device, and the pickling device includes a dispensing tank 23 and a medicament pump 24, and the dispensing tank 23 The outlet of the medicament pump 24 is connected to the inlet of the medicament pump 24, and the outlet of the medicament pump 24 is connected to the inlet of the pipeline filter 12.

The pressure reducing device 20 is an automatic back pressure valve.

The gas-liquid separation device 21 is a gas-liquid separator. A liquid level gauge (LIC10) is set on the gas-liquid separator, and an automatic regulating valve V14 is set on the liquid outlet pipeline of the gas-liquid separator, and the opening of the automatic regulating valve V14 controls the liquid level gauge (LIC10) to reach the set value.

The tail gas treatment device 22 is an activated carbon adsorber.

In general, the system has a high degree of automation and is safe and reliable in operation. The inlet pipeline of the oxygen booster 4 is equipped with an oxygen flow meter (FIC01) and an automatic adjustment valve V1 for the venting bypass, and the opening of the automatic adjustment valve V1 controls the oxygen flow rate entering the system to reach the required set value; A pressure sensor (PIC02) and an automatic valve V2 are set on the pipeline at the outlet of the inner tube. When the pressure (PIC02) is lower than the pressure (PIC06) of the reaction device 6, the valve V2 is closed and the oxygen supply is stopped; until (PIC02) is higher than the pressure of the reaction device 6 6 pressure (PIC06), the valve V2 is opened to start oxygen supply. The wastewater regulating tank 11 is provided with an agitator and an online pH meter (pHIC03), which can automatically adjust the start and stop of the acid-base pump 10 to adjust the wastewater to a set pH value. A flowmeter (FIC04) is installed on the pipeline before the high-pressure plunger pump 13 to automatically adjust the frequency converter frequency of the plunger pump to realize the automatic adjustment of the flow rate. Temperature sensors (TIC06) and (TIC07) are respectively arranged on the inner tube inlet and outlet pipelines of the third heat exchanger 15, and the temperature sensor (TIC06) controls the opening and closing of the inlet and outlet valves V7, V8 and V9 of the third heat exchanger 15, The temperature sensor (TIC07) automatically controls the heating power of the heat conduction oil heater 17. The reaction device 6 is provided with a pressure sensor (TIC09), which is linked with the opening degree of the automatic back pressure valve of the decompression device 20 to automatically control the system pressure. The gas-liquid separation device 21 is equipped with a liquid level gauge (LIC10) on the gas-liquid separator, and a regulating valve V14 is set on the liquid outlet pipeline of the gas-liquid separator to automatically adjust the opening of the valve V14 to control the liquid level gauge (LIC10) to reach the set value.

Example 2

The method of wet oxidation treatment of high-concentration organic wastewater by using the above system:

When the system is running:

1. The air is pressurized to 0.4-0.8 MPa by the air compressor 1, and enters the first PSA oxygen generator tank 2 or the second PSA oxygen generator tank 3; among them, the PSA oxygen generator tanks are one for use and one for standby , when one oxygen generator is preparing high-purity oxygen, the other is discharging nitrogen for backup. Through the first PSA oxygen generator tank 2 or the second PSA oxygen generator tank 3, high-purity oxygen with a purity of more than 90% can be produced, and the opening of the valve V1 is automatically adjusted to control the oxygen flow rate entering the system to reach the required set value The high-purity oxygen can be pressurized by the oxygen booster 4 to a reaction pressure of 5-12MPa, and the pressurized high-purity oxygen enters the inner tube of the second heat exchanger 5 to exchange heat with the fluid after the reaction, and the temperature after preheating It can reach 250-300°C and enter the reaction device 6 directly. During operation, when the pressure (PIC02) is lower than the pressure (PIC06) of the reaction device 6, the valve V2 is closed and the oxygen supply is stopped; until (PIC02) is higher than the pressure of the reaction device 6 (PIC06), the valve V2 is opened and the oxygen supply is started oxygen.

2. The waste water is pre-stored in the waste water storage tank 7. According to the actual pH of the waste water, an appropriate amount of acid (such as HNO ₃ ) or lye (such as KOH) is pre-stored in the acid-base tank 8, and the waste water pump 9 and the acid-base pump are turned on. 10 Add waste water and acid-base to the waste water regulating tank 11, start the agitator at the same time and monitor the pH of the mixed material, so that the pH of the material is controlled at the set value (pH is 6-9). The adjusted material passes through the pipeline filter 12 to filter out particulate matter and enters the high-pressure plunger pump 13. After the pressurization and flow control of the high-pressure plunger pump 13, the material enters the inner tube of the first heat exchanger 14 to exchange with the reacted fluid. If the temperature at the outlet of the inner tube of the first heat exchanger 14 is less than 200-250°C, it can enter the third heat exchanger 15 and be further heated with the heat transfer oil, and the material that reaches the preheating condition enters the reaction device 6; The outlet temperature of the inner tube of the device 14 has reached 200-250° C., and can directly enter the reaction device 6 through the bypass of the inlet and outlet of the third heat exchanger 15 .

3. Start the heat-conducting oil pump 16 and the heat-conducting oil heater 17. After being heated, the heat-conducting oil enters the inlet of the outer pipe of the third heat exchanger 15, and then flows from the outlet of the outer pipe of the third heat exchanger 15 back to the heat-conducting oil heating system for recycling . After the system is running normally, the power of the heat transfer oil heater 17 is automatically adjusted according to the temperature at the outlet of the inner tube of the third heat exchanger 15. When the temperature sensor TIC06 reaches the set temperature, the bypass valve V9 is automatically opened, and V7 and V8 are automatically closed. The third heat exchanger 15 stops using, and the heat conduction oil heater 17 stops heating at the same time, which can reduce the system operating cost. In order to protect the safety of the heat transfer oil heating system, the heat transfer oil pump 16 will always run.

4. The preheated high-purity oxygen and the material enter the reaction device 6 together, and a wet oxidation reaction occurs. The reaction temperature is 250-300° C., the reaction pressure is 5-12 MPa, and the reaction time is 1-2 hours. After the reaction, the refractory organic matter in the organic wastewater is decomposed into small molecular compounds, the phosphorus element in the organic phosphorus compound is decomposed into inorganic phosphorus, and the nitrogen element in the organic nitrogen compound is decomposed into ammonia nitrogen, which improves the biochemical efficiency of wastewater while removing COD. sex. The gas-liquid mixture processed by the reaction device 6 enters the outer tube of the second heat exchanger 5 to exchange heat with high-pressure oxygen, then enters the outer tube of the first heat exchanger 14 to exchange heat with waste water, and then enters the outer tube of the cooler 19. Tube and clean water heat exchanger, the temperature of the gas-liquid mixture after three-stage cooling drops to 50-80°C, then drops to normal pressure through the pressure-reducing device 20, and enters the gas-liquid separator after the pressure is reduced. The gas enters the activated carbon adsorber through the upper part of the gas-liquid separator for treatment and then is discharged, and the liquid is discharged from the outlet at the lower end of the gas-liquid separator for centralized treatment.

5. When the system is running normally, the valves V10 and V12 are opened, the valves V11 and V13 are closed, and the preheated waste water and oxygen enter the follow-up equipment through the reaction device 6 . When the system is running to remove waste in the reaction device 6, valves V11 and V13 are opened, valves V10 and V12 are closed, and the preheated waste water and oxygen do not enter the reaction device 6, but directly enter the follow-up equipment. Automatically adjust the opening of the decompression device 20 to reduce the system pressure by 2 to 3 MPa. The materials and some wastes in the reaction device 6 enter the cooler 19 from the inlet of the reaction device 6 through the valve V11, and enter the gas-liquid after being depressurized by the decompression device 20. Separator 21 performs separation.

6. The clear water is stored in the clear water storage tank 25, and the clear water pump 26 is used to pump water into the inlet of the outer pipe of the cooler 19, and the clear water at the outlet of the outer pipe of the cooler 19 flows back to the clear water storage tank 25 for recycling; the clear water in the tank is regularly replaced to ensure cooling Effect.

7. After the system shuts down, perform normal water flushing first, then start the heat transfer oil heater 17 to keep the temperature in the reaction device 6 at 60-80°C, and then start the medicine pump 24 to extract the medicine stored in the medicine dispensing tank 23 to the pipeline and system Pickling to remove scale. Wherein, the pickling agent is 2% HNO ₃ ; the pickling duration is more than 8 hours.

Utilize the wet oxidation treatment system of the high-concentration organic wastewater of this embodiment 1 and the method for embodiment 2 to carry out wet oxidation treatment to glyphosate and dimethoate pesticide wastewater, and the effect is shown in Table 1.

Table 1 Treatment effect of wet oxidation on glyphosate and dimethoate pesticide production wastewater

Claims (13)

1. A wet oxidation treatment system for high-concentration organic wastewater, characterized in that: It includes a pretreatment device, a heat conduction oil heating device and a reaction device (6) sequentially connected through pipelines; A first heat exchanger (14) is arranged between the pretreatment device and the heat transfer oil heating device, and the inner pipe of the first heat exchanger (14) is communicated; The inlet of the reaction unit (6) is provided with a bypass that feeds oxygen, directly connected to the oxygen generator; the bypass that feeds oxygen is provided with a second heat exchanger (5), through which the second heat exchanger ( 5) the inner pipe makes the inlet of the oxygen generator communicate with the reaction unit (6); The outlet of the reaction device (6) is connected to the second heat exchanger (5) outer pipe, the first heat exchanger (14) outer pipe, cooling device, decompression device (20), gas-liquid separation device ( 21) and tail gas treatment device (22). 2. The wet oxidation treatment system for high-concentration organic wastewater according to claim 1, wherein a bypass pipe is provided between the inlet and outlet of the heat-conducting oil heating device, and a heat-conducting oil heating device is provided for temporarily terminating Working temperature sensors and automatic valves. 3. The wet oxidation treatment system of high-concentration organic wastewater according to claim 1, characterized in that, a bypass for the reaction device (6) slagging is provided between the inlet of the reaction device (6) and the inlet of the cooling device Pipes and automatic valves, bypass pipes and automatic valves are provided between the inlet and outlet of the reaction device (6) to temporarily prevent oxygen and waste water from entering the reaction device (6) when the reaction device (6) discharges slag. 4. The wet oxidation treatment system of high-concentration organic wastewater according to any one of claims 1-3, characterized in that, the pretreatment device comprises a wastewater regulating tank (11), and the wastewater regulating tank (11) There are two inlets, one is sequentially connected to the waste water pump (9) and the waste water storage tank (7) through the pipeline, and the other is connected to the automatic adjustment acid-base pump (10) and the acid-base storage tank (8) through the pipeline in sequence; The outlet of the tank (11) is sequentially connected to the pipeline filter (12) and the high-pressure plunger pump (13), and the outlet of the high-pressure plunger pump (13) communicates with the inner pipe of the first heat exchanger (14). 5. The wet oxidation treatment system of high-concentration organic wastewater according to any one of claims 1-3, characterized in that, the heat-conducting oil heating device comprises a heat-conducting oil pump (16), a heat-conducting oil heater (17), The third heat exchanger (15) and heat conduction oil head tank (18), wherein, the outlet of heat conduction oil pump (16) is connected with the inlet of heat conduction oil heater (17), and the outlet of heat conduction oil heater (17) is connected with the third The inlet of the heat exchanger (15) outer pipe is connected, and the outlet of the third heat exchanger (15) outer pipe returns to the inlet of the heat transfer oil pump (16), and the inlet and outlet of the heat transfer oil pump (16) are connected in parallel with the heat transfer oil head tank (18). 6. The wet oxidation treatment system of high-concentration organic wastewater according to any one of claims 1-3, characterized in that, a catalyst box is provided in the reaction device (6); the wall of the reaction device (6) It consists of inner and outer layers, the outer layer is a pressure-bearing layer made of carbon steel or stainless steel, and the inner layer is a corrosion-resistant layer made of nickel-based alloys. 7. The wet oxidation treatment system of high-concentration organic wastewater according to any one of claims 1-3, characterized in that, the oxygen generator comprises an air compressor (1), a first Pressure swing adsorption oxygen generator (2), second pressure swing adsorption oxygen generator (3) and oxygen booster (4), wherein, the first pressure swing adsorption oxygen generator (2) and the second pressure swing adsorption The inlets of the adsorption oxygen generator (3) are respectively provided with nitrogen discharge bypasses, and the inlets of the oxygen booster (4) are provided with oxygen venting bypasses, which are automatically adjusted by valves and oxygen flowmeters. 8. The wet oxidation treatment system of high-concentration organic wastewater according to any one of claims 1-3, wherein the cooling device comprises a clear water storage tank (25) and a clear water pump (26) connected in sequence through pipelines ) and cooler (19), a bypass pipeline is provided between the outlet of the clear water pump (26) and the outlet of the waste water regulating tank (11), and the bypass pipeline is connected with a pickling unit, and the pickling unit It includes a medicine dispensing tank (23) and a medicine pump (24), and when the system is shut down for pickling, the switch of the pipeline is realized through the valve. 9. The wet oxidation treatment system of high-concentration organic wastewater according to any one of claims 1-3, characterized in that, the decompression device (20) is an automatic back pressure valve, and the gas-liquid separation device ( 21) is a gas-liquid separator, and the tail gas treatment device (22) is an activated carbon adsorber. 10. Utilize the system described in claim 1 to carry out the method for wet oxidation treatment of high-concentration organic waste water, it is characterized in that, make high-purity oxygen after the air enters the oxygen generator, after passing through the second heat exchanger (5) inner tube Enter the reaction device (6), at the same time, the organic waste water passes through the pretreatment device, after passing through the inner tube of the first heat exchanger (14), enters the reaction device (6) after being heated by the heat conduction oil heating device started, and the reaction device (6 ), high-purity oxygen and organic waste water undergo wet oxidation reaction, and the high-temperature gas-liquid mixture after the reaction enters the outer tube of the second heat exchanger (5) and the first heat exchanger (14) through the outlet of the reaction device (6) ) to exchange heat with high-purity oxygen and organic waste water respectively, then cool down through the cooling device, and then drop to normal pressure through the decompression device (20), and enter the gas-liquid separation device (21) after decompression, and the gas The upper part of the gas-liquid separation device (21) enters the tail gas treatment device (22) for treatment and then is discharged, and the liquid is discharged from the water outlet at the lower end of the gas-liquid separation device (21) for centralized treatment. 11. The method according to claim 10, characterized in that, in the reaction device (6), high-purity oxygen and organic waste water are reacted at 250-300° C. and 5-12 MPa for 1-2 hours. 12. The method according to claim 10, characterized in that, a bypass pipeline is provided between the inlet and outlet of the heat transfer oil heating device, and a temperature sensor and an automatic valve for temporarily stopping the work of the heat transfer oil heating device are provided, The heat conduction oil heating device is started only when the system is started and the feed preheating temperature is lower than the set temperature, otherwise it is directly connected through the bypass pipeline. 13. The method according to claim 10, characterized in that, a bypass pipe and a valve for slagging of the reaction device (6) are provided between the inlet of the reaction device (6) and the inlet of the cooling device, and the reaction device (6) There are bypass pipes and valves for temporarily preventing oxygen from entering the reaction device (6) between the inlet and outlet. When it is necessary to discharge slag from the reaction device (6) during operation, switch the valve so that the preheated Waste water and oxygen do not enter the reaction device (6) but directly enter the follow-up equipment. At the same time, the pressure of the reaction device (6) is reduced by 2 to 3 MPa through the pressure reducing device (20), and the residue and part of the waste in the reaction device (6) are discharged from the reaction device. The inlet of (6) enters the cooler (19), and then enters the gas-liquid separation device (21) for separation and treatment after being decompressed by the decompression device (20) and then discharged.