A PTA tail gas scrubber and scrubbing liquid treatment method

Abstract

The present invention discloses a PTA tail gas washing tower and a washing liquid treatment method, which relates to the technical field of chemical equipment, wherein the PTA tail gas washing tower includes a countercurrent high-temperature cooling device, a primary washing device, a secondary washing device, and a deep washing device; the countercurrent high-temperature cooling device includes a tail gas circulation cooling pipe and a cooling spray pipe, and the tail gas is cooled by spraying cooling water; the primary washing device and the secondary washing device are provided with a multi-layer filler filter plate and a spray head; the deep washing device includes a bottom air inlet, a waste liquid discharge hole and a washing liquid addition hole, and the present invention also relates to a PTA tail gas washing liquid treatment method. The tail gas washing device in the present invention has a simple structure and is convenient for later maintenance. Through the multi-stage treatment of the washing waste liquid resource recovery, physical and chemical and biochemical treatment, the pollutants are removed while balancing the economic and environmental protection issues.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical equipment, and more specifically, to a PTA tail gas washing tower and a washing liquid treatment method. Background Art

[0002] The p-xylene oxidation method is adopted in the production of PTA, and the generated tail gas contains a large amount of acidic gases (such as acetic acid vapor and carbon dioxide), volatile organic compounds (VOCs, such as methanol, benzene) and solid particles (catalyst dust, etc.). The fine catalyst dust particles in the tail gas cannot be completely captured by the washing liquid, and the residual particles are easily discharged in excess of the standard. Directly discharging these tail gases will cause serious pollution to the environment, and the tail gas also contains some recyclable resources (such as acetic acid), which need to be effectively treated. The absorption efficiency of the washing tower for carbon dioxide and other acidic gases (such as acetic acid vapor) may be insufficient, resulting in incomplete tail gas treatment, and the packing components in the washing tower are susceptible to pollutant deposition or scaling, which reduces the washing efficiency. Therefore, in order to solve the above-mentioned technical problems, the present invention proposes a PTA tail gas washing tower and a washing liquid treatment method. Summary of the invention

[0003] In view of the shortcomings of the prior art, the first object of the present invention is to provide a PTA tail gas washing tower.

[0004] To achieve the above object, the present invention provides the following technical scheme: a PTA tail gas washing tower, comprising a countercurrent high-temperature cooling device, a primary washing device, a secondary washing device, and a deep washing device, characterized in that the countercurrent high-temperature cooling device comprises a cooling water pipe 101, a cooling spray pipe 102, a tail gas inlet 103, a tail gas outlet 104, a tail gas circulation cooling pipe 105, a fan drive motor 106, a fan 107, a cooling pipe water pump 108, and a simple ladder 109, at least one group of cooling spray pipes is provided in the countercurrent high-temperature countercurrent cooling device, the tail gas circulation cooling pipe is located below the cooling spray pipe, and the fan is located above the cooling spray pipe;

[0005] The primary washing device comprises a primary washing tank body with a cooled tail gas inlet 201, a primary washing waste liquid discharge hole 202 at the bottom, and a primary washing tail gas discharge outlet 206 and a lifting hole 207 at the upper end, the primary tank body is supported by three brackets, a primary spray head 203 and a primary packing layer 205 are arranged inside the primary tank body, the primary spray head is arranged on a primary flange pipe 204, the primary spray head is located above the primary packing layer, and the cooled tail gas inlet is located below the primary packing layer;

[0006] The secondary washing device includes a secondary washing tank body with a primary washing tail gas inlet 301, a secondary washing waste liquid discharge hole 302 at the bottom, and a secondary washing tail gas discharge outlet 306 and a lifting hole 307 at the upper end. The secondary tank body is supported by three brackets, and a secondary spray head 303 and a secondary packing layer 305 are arranged inside the secondary tank body;

[0007] The deep washing device includes a deep washing tank body with a secondary washing exhaust gas inlet 401 at the bottom, a deep washing waste liquid discharge hole 402 and a deep washing exhaust gas discharge outlet 404 at the upper end, and a deep washing tank body with a lifting hole. The deep washing tank body is supported by three brackets and a deep washing liquid flange pipe 403 is provided on the deep washing tank body.

[0008] Preferably, the simple ladder 109 is located on the side of the countercurrent high-temperature cooling device.

[0009] Preferably, the primary spray head is arranged on the primary flange pipe 204 , the primary spray head 203 is located above the primary packing layer 205 , and the cooled exhaust gas inlet 201 is located below the primary packing layer 205 .

[0010] Preferably, the secondary spray head is arranged on the secondary flange pipe 304 , the secondary spray head 303 is located above the secondary packing layer 305 , and the primary washing tail gas inlet 301 is located below the secondary packing layer 305 .

[0011] Preferably, the primary washing device and the secondary washing device have the same structure.

[0012] Preferably, at least one set of spray heads is provided in the primary washing tank.

[0013] Preferably, at least one primary filler layer is provided in the primary washing tank.

[0014] Preferably, at least one set of spray heads is provided in the secondary washing tank.

[0015] Preferably, at least one primary filler layer is provided in the secondary washing tank.

[0016] Preferably, the cooling medium in the countercurrent high-temperature cooling device is cooling water or cooling liquid.

[0017] Preferably, the washing liquid in the primary washing device is circulating water or a washing liquid containing acetic acid.

[0018] Preferably, the washing liquid in the secondary washing device is a sodium hydroxide solution or a sodium carbonate solution.

[0019] Preferably, the washing liquid in the deep washing device is hydrogen peroxide or sodium hypochlorite.

[0020] Preferably, the primary filler layer (205) in the primary washing device is a plastic net made of PP or PE material.

[0021] Preferably, the secondary filler layer (305) in the secondary washing device is a plastic net made of PP or PE material.

[0022] The second object of the present invention is to provide a method for treating the PTA tail gas washing liquid produced by the above-mentioned washing tower, comprising the following steps:

[0023] S1: Collect the washing waste liquid discharged from the primary washing device, the secondary washing device and the deep washing device into a storage tank;

[0024] S2: Separate larger particles and impurities from the washing liquid by gravity settling, and use filtering equipment to remove finer particles;

[0025] S3: adding a neutralizing agent to the washing waste liquid to adjust the pH value of the washing waste liquid to neutral;

[0026] S4: The washing waste liquid is sent to the distillation tower, and the condensate is separated into two parts through the collector, which can be recycled and stored, and the light phase organic matter acetic acid and toluene used in the subsequent process and the heavy phase water which can be reused as washing liquid or enter the wastewater treatment system;

[0027] S5: adding sodium carbonate to the washing waste liquid to cause the metal ions to form cobalt carbonate and manganese carbonate precipitation, which are then removed by centrifugal separation;

[0028] S6: sending the washing waste liquid to the anaerobic generator to decompose acetic acid and hydrogen by microorganisms under anaerobic conditions;

[0029] S7: In the aerobic reactor, aeration increases the oxygen content to further degrade acetic acid and toluene;

[0030] S8: evaporating the water in the washing waste liquid through an evaporation device, concentrating the inorganic salt in the waste liquid to precipitate solids, and recovering them by filter pressing;

[0031] S9: Activated carbon is used to remove trace pollutants, and coagulants are added to remove residual fine particles;

[0032] S10: Online monitoring equipment detects the treated wastewater to ensure that COD, BOD and heavy metal indicators are qualified.

[0033] The PTA tail gas washing liquid treatment method of the present invention further comprises: in step S4, the distillation tower heat exchanger preheats the waste liquid distillation temperature to 80°C, and the heating temperature is set to 118°C;

[0034] In step S5, the reaction temperature is maintained at 50-60°C.

[0035] The method for treating PTA tail gas washing liquid of the present invention further comprises: in step S1,

[0036] It is characterized in that: in step S3, the neutralizing agent is an acidic or alkaline solution.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention adopts a multi-stage washing process and sets a special washing section in the washing tower according to the physical and chemical characteristics of different pollutants. For example, an alkali washing section is set for acidic waste gas pollutants to remove the acidic components through alkali neutralization. The division of labor and synergy between the various sections ensure the targeted removal of different pollutants, greatly improve the washing efficiency, and reduce the content of residual pollutants in the tail gas.

[0039] 2. The present invention overcomes the problem of blockage of traditional structured packing due to narrow pores and uneven gas-liquid distribution by arranging self-cleaning mesh packing inside the washing tower. The washing liquid flows evenly along the surface of the mesh packing to form a continuous and stable liquid film, which improves the mass transfer efficiency. In addition, the mesh structure of the packing can use the gas-liquid flushing force to self-clean, avoid the long-term accumulation of particles and adhesions, reduce the maintenance frequency and extend the service life of the packing.

[0040] 3. The present invention uses a multi-stage treatment of the washing waste liquid and a comprehensive application of physical, chemical and biological technologies to achieve the removal of pollutants while further recovering available resources. Suspended matter and large particle impurities in the waste liquid are removed by precipitation separation and filtration; then, a neutralizing agent such as sodium carbonate is added to precipitate heavy metal ions (such as cobalt and manganese), and the components are recovered by centrifugal equipment for industrial production; the residual organic matter in the waste liquid is decomposed by anaerobic fermentation, and the generated by-products (such as methane) can be reused for energy supply. Finally, the difficult-to-degrade organic matter is further degraded by aerobic treatment, so that the effluent meets the discharge standards, and at the same time, the acetic acid in the waste liquid is separated and purified for secondary utilization. The entire process focuses on the combination of resource recycling and pollution control, reducing environmental pressure while improving economic benefits, and achieving the goal of green production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 It is a schematic diagram of the structure of the countercurrent high-temperature cooling device in the present invention;

[0043] Figure 2 It is a structural schematic diagram of the primary washing device in the present invention;

[0044] Figure 3 It is a structural schematic diagram of the secondary washing device in the present invention;

[0045] Figure 4 It is a schematic diagram of the structure of the deep washing device in the present invention.

[0046] 101. Cooling water pipe; 102. Cooling spray pipe; 103. Exhaust gas inlet; 104. Exhaust gas outlet; 105. Exhaust gas circulation cooling pipe; 106. Fan drive motor; 107. Fan; 108. Cooling pipe water pump; 109. Simple ladder; 201. Cooled exhaust gas inlet; 202. Primary washing waste liquid discharge hole; 203. Primary spray head; 204. Primary flange pipeline; 205. Primary packing layer; 206. Primary washing exhaust gas outlet; 207. Lifting hole; 301. Primary washing exhaust gas inlet; 302. Secondary washing waste liquid discharge hole; 303. Secondary spray head; 304. Secondary flange pipeline; 305. Secondary packing layer; 306. Secondary washing exhaust gas outlet; 401. Secondary washing exhaust gas inlet; 402. Deep washing waste liquid discharge hole; 403. Deep washing liquid flange pipeline; 404. Deep washing exhaust gas outlet. DETAILED DESCRIPTION

[0047] like Figure 1-4 As shown, the present invention provides a PTA tail gas washing tower, including a countercurrent high-temperature cooling device, a primary washing device, a secondary washing device and a deep washing device, the countercurrent high-temperature cooling device is provided with a cooling water pipe 101, the cooling water enters the cooling spray pipe 102 through the cooling water pipe 101 under the lifting of the cooling pipe water pump 108, the PTA tail gas is introduced into the tail gas circulation cooling pipe 105 from the tail gas inlet hole 103, the cooling spray pipe 105 sprays water to cool the tail gas circulation pipe 105, the tail gas outlet hole 104 discharges the cooled tail gas, the fan driving motor 106 drives the fan 107 to rotate, accelerates the cooling of the cooling water sprayed from the cooling spray pipe 102 and takes away the heat, and the simple ladder 109 is located on the side for later maintenance of the equipment.

[0048] The primary washing device includes a primary washing tank body with a cooled exhaust gas inlet 201, a primary washing waste liquid discharge hole 202 at the bottom, and a primary washing exhaust gas outlet 206 and a lifting hole 207 at the upper end. The primary tank body is supported by three brackets. A primary spray head 203 and a primary packing layer 205 are arranged inside the primary tank body. The primary spray head is arranged on a primary flange pipe 204. The primary spray head is located above the primary packing layer. The cooled exhaust gas inlet is located below the primary packing layer. The cooled exhaust gas is sprayed and washed by the acetic acid washing liquid sprayed by the primary packing layer and the primary spray head, and finally sent out from the primary washing exhaust gas outlet at the top.

[0049] The secondary washing device includes a secondary washing tank body with a primary washing exhaust gas inlet 301, a secondary washing waste liquid discharge hole 302 at the bottom, and a secondary washing exhaust gas outlet 306 and a lifting hole 307 at the upper end. The secondary tank body is supported by three brackets. A secondary spray head 303 and a secondary packing layer 305 are arranged inside the secondary tank body. The exhaust gas after primary washing is sprayed and washed with sodium hydroxide solution sprayed from the secondary packing layer and the secondary spray head, and finally sent out from the secondary washing exhaust gas outlet at the top.

[0050] The deep washing device comprises a deep washing tank body with a secondary washing exhaust gas inlet 401, a deep washing waste liquid discharge hole 402 and a deep washing exhaust gas outlet 404 at the top, and a deep washing tank body with a hoisting hole. The deep washing tank body is supported by three brackets. A deep washing liquid flange pipeline 403 is provided on the deep washing tank body. The exhaust gas after the secondary washing is introduced into the sodium hypochlorite solution of the tank body through the flange pipeline for washing, and finally sent out from the deep washing exhaust gas outlet at the top.

[0051] The PTA tail gas washing liquid treatment method of the present invention specifically comprises the following steps:

[0052] (1) Collect the washing waste liquid discharged from the primary washing device, the secondary washing device, and the deep washing device into a storage tank;

[0053] (2) The washing waste liquid enters a dedicated sedimentation tank or sedimentation tank, where the flow rate of the liquid slows down and the larger particles (such as dust, solid impurities, etc.) suspended in the washing waste liquid sink to the bottom of the tank under the action of gravity. To improve the sedimentation efficiency, a separation zone is designed to extend the liquid residence time and separate the particles through internal baffles or multi-stage sedimentation structures. The settled particles are concentrated at the bottom sewage outlet and are regularly cleaned or transported to the solid waste treatment system through the sewage valve. After gravity sedimentation, the washing liquid flows into the sand filter and further filters the smaller suspended particles through the quartz sand layer filled in the filter. The filtered liquid is discharged from the outlet and the fine particles remain in the sand layer. To maintain the filtering effect, the sand filter needs to be backwashed regularly, using clean water to backwash the sand layer and remove the accumulated particles.

[0054] (3) Washing waste liquid usually contains acidic components discharged during the production of acetic acid and PTA, which are highly acidic. The pH value of the waste liquid is preliminarily measured using an online pH detector to confirm its acid strength. The pH value is usually between 4 and 6. According to the acidity and treatment volume of the waste liquid, a neutralizer solution of appropriate concentration is prepared. For example, sodium hydroxide can be prepared as a 5%-10% alkali solution. The solution is prepared using corrosion-resistant equipment (such as a stirring tank, a stainless steel container) to ensure that the neutralizer is completely dissolved or forms a uniform emulsion. The neutralizer solution is continuously added to the waste liquid flow through an automatic metering pump. For small-scale waste liquid treatment, the neutralizer can be injected manually or by an intermittent pump. A mixing reaction tank or a dosing mixing tank is set up, and a mechanical agitator is used to mix the neutralizer solution. Or use a gas stirring device to fully mix the neutralizer and the waste liquid to ensure that the neutralizer and the waste liquid are in uniform contact. To accelerate the reaction, the stirring intensity can be controlled or the residence time of the waste liquid can be extended (10-30 minutes); install a pH monitor in the mixing reaction tank or the dosing mixing tank to monitor the pH value changes of the waste liquid in real time to ensure that the neutralization process is controlled or set up an automatic control system to adjust the amount of neutralizer added according to the pH feedback signal to avoid excessive neutralization causing the waste liquid to become alkaline; if the pH value of the waste liquid after neutralization is lower than 6, continue to add an appropriate amount of neutralizer. If the pH value is too high (greater than 8), use acetic acid to reversely adjust it to neutrality; use sodium hydroxide to neutralize and generate salt, and the waste liquid passes through a sedimentation tank to separate the precipitate. The waste liquid after neutralization can enter the subsequent treatment unit.

[0055] (4) Preheat the waste liquid to a temperature close to the distillation temperature (70-80°C) through a heat exchanger to reduce the energy consumption in the tower; use a continuous distillation tower with packing or multi-layer tower plates in the tower, control the heating temperature at 118°C, and configure a heat-integrated heat exchanger or reboiler to fully recover the waste heat generated during the distillation process; the washing waste liquid is stably fed into the feed section of the distillation tower through a metering pump, and the feed flow rate is dynamically adjusted according to the tower's processing capacity and the properties of the waste liquid; a heater is installed at the bottom of the tower to heat the waste liquid to the target temperature, so that the organic matter is vaporized into steam, while the non-volatile components (salt, solid impurities) remain at the bottom of the tower to form residual liquid; the tower is filled with The material or tower plate can strengthen the gas-liquid contact, so that the low-boiling point organic matter gradually rises and separates, the water vapor and organic mixed gas moves to the top of the tower, and the high-boiling point substances and impurities gather at the bottom of the tower; a condenser is set on the top of the tower, and the rising steam is quickly condensed into liquid by a cooling medium (cooling water or frozen brine), and the condensate is separated into two parts by a collector: the light phase organic matter (acetic acid, toluene) is recovered and stored for subsequent processes or sold, and the heavy phase water can be reused as a washing liquid or enter wastewater treatment; the residual liquid at the bottom of the distillation tower contains non-volatile impurities and high-boiling point substances, which are transported to solid waste treatment or concentrated and dried through a sewage pipe.

[0056] (5) The washing waste liquid contains metal ions such as cobalt ions and manganese ions. According to the metal ion concentration of the waste liquid, a sodium carbonate solution of appropriate concentration (5%-10%) is prepared to ensure uniform dispersion during the reaction. The reaction temperature is maintained at 50-60°C. A stirring device or a dissolving tank is used to completely dissolve the sodium carbonate to prevent particles from clogging the feed pipe. The waste liquid is added in batches according to the amount of waste liquid to be treated, and the uniformity of the reaction is ensured by quantitative control. While adding sodium carbonate, mechanical stirring or air stirring is used to make the sodium carbonate fully react with the metal ions in the waste liquid to form a uniform precipitate. The waste liquid after the reaction is sent to a centrifuge, and the centrifugal force generated by high-speed rotation (3000-5000 rpm) is used to separate the precipitate (cobalt carbonate and manganese carbonate) from the liquid phase. After drying, it is sold as a raw material for cobalt-manganese compounds or recovered by chemical reduction process with high purity cobalt and manganese. The separated liquid can enter the subsequent treatment link.

[0057] (6) Send the washing waste liquid to the anaerobic generator. According to the concentration of organic matter in the waste liquid, set the liquid residence time to 12-48 hours and control the organic load rate of the reactor to 2-10kg COD / m 3 ·d; Under anaerobic conditions, microorganisms gradually degrade acetic acid and hydrogen in the wastewater into methane (CH4), carbon dioxide (CO2) and a small amount of by-products.

[0058] (7) After the washing wastewater from PTA tail gas treatment is treated in an anaerobic reactor, the organic matter concentration (COD) has been greatly reduced, but the residual COD is still higher than the emission standard and is further degraded through aerobic treatment; the wastewater temperature is controlled at 20-30°C, the pH value of the wastewater is detected and adjusted to between 6.5 and 8.5 (by adding acid or alkali), and a suitable aerobic reactor is selected according to the wastewater flow, COD concentration and treatment standard. The dissolved oxygen concentration (DO) in the wastewater is maintained at 2-4 mg / L through aeration. The wastewater stays in the aerobic reactor for 6-12 hours. During aeration, the stirring device is started to fully mix the wastewater and microorganisms; the effluent from the aerobic reactor is passed through a secondary sedimentation tank to separate the activated sludge and the treated clean water, and part of the separated activated sludge is returned to the aerobic reactor.

[0059] (8) If there are suspended solids or sediments in the waste liquid, they are first removed by filtering equipment, and the pH value of the waste liquid is adjusted to neutral to reduce the corrosion of the acid or alkalinity to the evaporation equipment. The waste liquid is preheated to 40-50°C before entering the evaporation equipment, and the evaporation temperature is controlled at 60-120°C. The operation is carried out under a vacuum environment (-0.08 to -0.09MPa) to concentrate the inorganic salts to 80-90% saturation state, thereby promoting the precipitation and crystallization of salts. The slurry after evaporation and concentration is discharged from the bottom of the evaporator and transported to a filter press to separate the inorganic salts from the liquid part in the slurry, and the separated mother liquor is returned to the evaporator for re-concentration. The inorganic salt crystals after filter pressing contain a certain amount of water, which are further dehydrated by drying equipment. The drying temperature is controlled at 80-120°C to make the water content less than 5%.

[0060] (9) The waste liquid flow rate is controlled at 5 L / min, the adsorption process is carried out at 30-40 ° C, and the dosage is adjusted to 5-10 g / L according to the pollutant concentration in the waste liquid; the pollutants in the waste liquid after adsorption are discharged and enter the subsequent coagulation treatment. According to the particle concentration and pH value in the waste liquid, the optimal dosage is determined through a small test, and an inorganic coagulant is added. In the coagulation tank, the coagulant and the waste liquid are fully mixed by rapid stirring at 100 rpm for 30-60 seconds; the stirring speed is slowed down to 20-40 rpm, and the reaction is carried out for 10-20 minutes to allow the colloidal particles to gradually form flocs; the waste liquid enters the sedimentation tank, and the flocs settle to the bottom by gravity for 0.5-2 hours to separate the clear liquid and sludge.

[0061] (10) Online monitoring equipment is used to detect the treated wastewater COD: ≤100mg / L, BOD: ≤30mg / L, heavy metals: manganese ≤0.1mg / L, cobalt ≤0.05mg / L.

[0062] Working principle:

[0063] The PTA tail gas enters the tail gas circulation cooling pipe 105 through the tail gas inlet hole 103. The cooling water is lifted by the cooling pipe water pump 108 and sprayed on the tail gas circulation cooling pipe 105 through the cooling water pipe 101 and the cooling spray pipe 102. The fan driving motor 106 drives the fan 107 to rotate, accelerating the cooling and flow of the cooling water.

[0064] The cooled exhaust gas enters the primary washing device through the cooled exhaust gas inlet 201, and the primary flange pipe 204 introduces acetic acid washing liquid, which is sprayed on the primary packing layer 205 through the primary spray head 203. The cooled exhaust gas passes through the primary packing layer 205 and the primary spray head 203 for primary washing in the rising process. The exhaust gas after primary washing is discharged through the top primary washing exhaust gas outlet 206, and the primary washing liquid waste is output to the waste liquid storage tank through the primary washing waste liquid discharge hole 202.

[0065] The tail gas after primary washing enters the secondary washing device through the primary washing tail gas inlet 301, and the secondary flange pipe 304 introduces the sodium hydroxide solution and sprays it on the secondary packing layer 305 through the primary and secondary spray heads 303. The tail gas after primary washing passes through the secondary packing layer 305 and the secondary spray head 303 for secondary washing in the rising process. The tail gas after secondary washing is discharged through the top secondary washing tail gas outlet 306, and the secondary washing waste liquid is output to the waste liquid storage tank through the secondary washing waste liquid discharge hole 302.

[0066] The tail gas after secondary washing enters the deep washing device through the secondary washing tail gas inlet 401, and the deep washing flange pipe 403 introduces the sodium hypochlorite solution into the tank body. The tail gas after secondary washing is fully reacted in the tank body and is discharged through the top deep washing tail gas outlet 404. The deep washing waste liquid is output to the waste liquid storage tank through the deep washing waste liquid discharge hole 402.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A PTA tail gas scrubber, comprising a countercurrent high-temperature cooling device, a primary scrubber, a secondary scrubber, and a deep scrubber connected in sequence, characterized in that: The countercurrent high-temperature cooling device comprises a cooling water pipe (101), a cooling spray pipe (102), an exhaust gas inlet hole (103), an exhaust gas outlet hole (104), an exhaust gas circulation cooling pipe (105), a fan drive motor (106), a fan (107), and a cooling pipe water pump (108); at least one group of cooling spray pipes (102) is provided in the countercurrent high-temperature countercurrent cooling device, the exhaust gas circulation cooling pipe is located below the cooling spray pipe, and the fan is located above the cooling spray pipe; the cooling water pipe (101) is connected to the cooling spray pipe (102); The primary washing device comprises a primary washing tank body having a cooled exhaust gas inlet (201) and a primary washing waste liquid discharge hole (202) at the bottom and a primary washing exhaust gas outlet (206) and a hanging hole (207) at the upper end, the primary tank body being supported by a bracket, a primary spray head (203) and a primary packing layer (205) being arranged inside the primary tank body, the primary spray head being arranged on a primary flange pipe (204), the primary spray head being located above the primary packing layer, and the cooled exhaust gas inlet being located below the primary packing layer; The secondary washing device comprises a secondary washing tank body having a primary washing tail gas inlet (301) and a secondary washing waste liquid discharge hole (302) at the bottom and a secondary washing tail gas discharge outlet (306) and a hanging hole (307) at the upper end, wherein the secondary tank body is supported by three brackets and a secondary spray head (303) and a secondary packing layer (305) are arranged inside the secondary tank body; The deep washing device comprises a deep washing tank body with a secondary washing exhaust gas inlet (401) at the bottom, a deep washing waste liquid discharge hole (402), a deep washing exhaust gas discharge outlet (404) at the upper end, and a deep washing tank body with a lifting hole. The deep washing tank body is supported by three brackets, and a deep washing liquid flange pipeline (403) is provided on the deep washing tank body.

2. A PTA tail gas scrubber according to claim 1, characterized in that: The simple ladder (109) is located on the side of the countercurrent high-temperature cooling device; The primary spray head is arranged on the primary flange pipe (204), the primary spray head (203) is located above the primary packing layer (205), and the cooled exhaust gas inlet (201) is located below the primary packing layer (205); The secondary spray head is arranged on the secondary flange pipe (304), the secondary spray head (303) is located above the secondary packing layer (305), and the primary washing tail gas inlet (301) is located below the secondary packing layer (305).

3. A PTA tail gas scrubber according to claim 1, characterized in that: At least one set of spray heads is provided in the primary washing tank; At least one primary filler layer is provided in the primary washing tank; At least one set of spray heads is provided in the secondary washing tank; At least one primary filler layer is arranged in the secondary washing tank.

4. A PTA tail gas scrubber according to claim 1, characterized in that: The cooling medium in the countercurrent high-temperature cooling device is cooling water; The washing liquid in the primary washing device is circulating water or a washing liquid containing acetic acid; The washing liquid in the secondary washing device is a sodium hydroxide solution or a sodium carbonate solution; The washing liquid in the deep washing device is hydrogen peroxide or sodium hypochlorite solution.

5. A PTA tail gas scrubber according to claim 1, characterized in that: The primary filler layer (205) in the primary washing device is a plastic net made of PP or PE material; The secondary packing layer (305) in the secondary washing device is a plastic net made of PP or PE material.

6. A method for treating PTA tail gas washing liquid, characterized in that: The steps include: S1: Collect the washing waste liquid discharged from the primary washing device, the secondary washing device and the deep washing device into a storage tank; S2: Separate larger particles and impurities from the washing liquid by gravity settling, and use filtering equipment to remove finer particles; S3: adding a neutralizing agent to the washing waste liquid to adjust the pH value of the washing waste liquid to neutral; S4: The washing waste liquid is sent to the distillation tower, and the condensate is separated into two parts through the collector, which can be recycled and stored, and the light phase organic matter acetic acid and toluene used in the subsequent process and the heavy phase water which can be reused as washing liquid or enter the wastewater treatment system; S5: adding sodium carbonate to the washing waste liquid to cause the metal ions to form cobalt carbonate and manganese carbonate precipitation, which are then removed by centrifugal separation; S6: sending the washing waste liquid to the anaerobic generator to decompose acetic acid and hydrogen by microorganisms under anaerobic conditions; S7: In the aerobic reactor, aeration increases the oxygen content to further degrade acetic acid and toluene; S8: evaporating the water in the washing waste liquid through an evaporation device, concentrating the inorganic salt in the waste liquid to precipitate solids, and recovering them by filter pressing; S9: Activated carbon is used to remove trace pollutants, and coagulants are added to remove residual fine particles; S10: Online monitoring equipment detects the treated wastewater to ensure that COD, BOD and heavy metal indicators are qualified.

7. A method for treating PTA tail gas scrubbing liquid according to claim 6, characterized in that: In step S4, the distillation tower heat exchanger preheats the waste liquid distillation temperature to 80°C, and the heating temperature is set to 118°C; In step S5, the reaction temperature is maintained at 50-60°C.

8. A method for treating PTA tail gas scrubbing liquid according to claim 6, characterized in that: In step S3, the neutralizing agent is an acidic or alkaline solution.

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