A PVC centrifugal mother liquor ozone tail gas treatment system

Abstract

This utility model relates to the field of ozone tail gas treatment technology, specifically a PVC centrifugal mother liquor ozone tail gas treatment system. It includes a centrifugal mother liquor buffer tank, a second tail gas outlet pipe connected to the upper side of the buffer tank, a wind-cooled composite cooler connected to the outlet port of the second tail gas outlet pipe and located on the outer wall of the mother liquor inlet pipe, a third electric valve located on the first tail gas outlet pipe section, a dual-branch decomposition unit connected to the outlet port of the gas-liquid separation unit, an ozone content detection and emission unit connected to the outlet port of the dual-branch decomposition unit, and a return branch connected to the ozone content detection and emission unit and the gas-liquid separation unit near their outlet ports. This device uses low-temperature mother liquor heat exchange and wind cooling to reduce tail gas temperature, saving energy and preventing catalyst deactivation. Excess tail gas is returned downstream to reduce the load on the separation tank, and the dual-branch design ensures compliance. The dual-branch design allows for maintenance without shutdown, meets the requirements of continuous PVC production, and provides audible and visual alarms for stability.

Description

Technical Field

[0001] This utility model relates to the field of ozone exhaust gas treatment technology, specifically to an ozone exhaust gas treatment system for PVC centrifugal mother liquor. Background Technology

[0002] With increasingly stringent environmental protection requirements, ozone exhaust gas generated during the deep treatment of PVC centrifugal mother liquor is often difficult to treat. Although the deep treatment system is designed with ozone exhaust gas treatment devices, the high water content of the ozone exhaust gas causes the treatment devices to fail to operate continuously and stably. As a result, the treated ozone exhaust gas does not meet the standards and is directly discharged into the atmosphere, which not only pollutes the environment but also endangers the health of employees.

[0003] A Chinese patent publication (patent number CN219879561U) describes an ozone catalytic oxidation tank tail gas treatment system. While this system can treat ozone tail gas through a gas-liquid separator, an ozone decomposition catalyst, and a return pipeline, it has the following shortcomings for scenarios where PVC centrifugal mother liquor ozone tail gas has high temperature (40-60℃), high moisture content, and requires continuous treatment: First, direct entry of high-temperature tail gas into the catalyst easily leads to catalyst activity decay, and the lack of energy-saving utilization of low-temperature mother liquor (20-25℃) results in energy waste. Second, when tail gas exceeds the standard, it is only recirculated for retreatment. Long-term treatment of tail gas exceeding the standard can easily saturate the catalyst, reduce its activity, and make it difficult to stably reduce it to the standard range (≤0.02ppm). Furthermore, the recirculated tail gas needs to be re-entered into the gas-liquid separator for treatment, which increases the load on the gas-liquid separator and leads to a decrease in separation efficiency. Third, it only configures a single ozone decomposition catalyst without a backup treatment branch. When the catalyst needs to be replaced or the equipment needs maintenance, the entire tail gas treatment system needs to be shut down, which cannot meet the needs of PVC production for 24-hour continuous tail gas treatment. Utility Model Content

[0004] The purpose of this invention is to provide a PVC centrifugal mother liquor ozone tail gas treatment system to solve the problems of existing devices where high-temperature tail gas causes catalyst activity decay and fails to utilize low-temperature mother liquor for energy saving; tail gas exceeding standards is recirculated for reprocessing, which easily leads to a decrease in catalyst activity, difficulty in achieving stable standards, and an increase in the load on the gas-liquid separator; and the system only has a single ozone decomposition catalyst with no backup branch, requiring system shutdown during equipment maintenance, which cannot meet the continuous processing needs of PVC production.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a PVC centrifugal mother liquor ozone tail gas treatment system, comprising a centrifugal mother liquor buffer tank, an ozone tail gas inlet pipe connected to the upper side of the centrifugal mother liquor buffer tank, a mother liquor inlet pipe extending through and to the bottom of the centrifugal mother liquor buffer tank, and a gas-liquid separation unit for gas-liquid separation of the tail gas; further comprising a second tail gas outlet pipe connected to the upper side of the centrifugal mother liquor buffer tank, an air-cooled composite cooler connected to the outlet port of the second tail gas outlet pipe and disposed on the outer wall of the mother liquor inlet pipe, and a gas-liquid separation unit connected to the outlet port of the air-cooled composite cooler and the gas-liquid separation unit. The system includes a first exhaust pipe connected to the unit's air inlet port, a third electric valve installed on the first exhaust pipe section, a dual-branch decomposition unit connected to the gas-liquid separation unit's exhaust port, an ozone content detection and emission unit connected to the dual-branch decomposition unit's exhaust port, a return branch connected to the main exhaust pipe of the ozone content detection and emission unit and the gas-liquid separation unit, a PLC controller, and an audible and visual alarm. The air-cooled composite cooler, gas-liquid separation unit, third electric valve, return branch, audible and visual alarm, and ozone content detection and emission unit are all electrically connected to the PLC controller.

[0006] Furthermore, the gas-liquid separation unit includes a primary gas-liquid separator connected to the outlet port of the first exhaust gas outlet pipe, a humidity sensor disposed on the outlet port of the primary gas-liquid separator, a first outlet pipe connected to the outlet port of the primary gas-liquid separator, a fifth electric valve disposed on the first outlet pipe section, a second branch pipe and a second outlet pipe connected to the wall of the first outlet pipe and respectively corresponding to the inlet and outlet ends of the fifth electric valve, a secondary gas-liquid separator connected to the inlet port of the second branch pipe and the outlet port of the second outlet pipe, a seventh electric valve disposed on the second outlet pipe section, and a sixth electric valve disposed on the second branch pipe section; the humidity sensor, the fifth electric valve, the sixth electric valve, and the seventh electric valve are all electrically connected to the PLC controller.

[0007] Furthermore, the outlet ports of both the primary gas-liquid separator and the secondary gas-liquid separator are connected to drain pipes. Liquid level sensors are installed at the bottom of the outer walls of both the primary and secondary gas-liquid separators. A fourth electric valve is installed on the drain pipe section. Both liquid level sensors and the two fourth electric valves are electrically connected to the PLC controller.

[0008] Furthermore, the dual-branch decomposition unit includes a first electric three-way valve connected to the outlet port of the first outlet pipe, two first branch pipes respectively connected to the other two interfaces of the first electric three-way valve, ozone decomposers respectively installed on the two first branch pipe sections, and a second electric three-way valve connected to the outlet ports of the two first branch pipes. The outlet ports of the two first branch pipes are respectively connected to the two non-common interfaces of the second electric three-way valve. Both the first electric three-way valve and the second electric three-way valve are electrically connected to the PLC controller.

[0009] Furthermore, the ozone content detection and emission unit includes a first connecting pipe connected to the common end of the second electric three-way valve, an ozone concentration sensor and an induced draft fan arranged sequentially on the first connecting pipe section along the airflow direction, an exhaust pipe connected to the exhaust port of the induced draft fan, and a first electric valve arranged on the exhaust pipe section; the ozone concentration sensor, the drive motor of the induced draft fan, and the first electric valve are all electrically connected to the PLC controller.

[0010] Furthermore, the return branch includes a return pipe connected to the first outlet pipe section and located between the outlet ends of the second outlet pipe, a second electric valve disposed on the return pipe section, and a one-way valve disposed on the return pipe section; the air inlet of the return pipe is connected to the pipe wall of the exhaust pipe and located between the induced draft fan and the first electric valve.

[0011] Furthermore, the air-cooled composite cooler includes a shell, an air-cooling component disposed on one side of the outer wall of the shell, and a coil connected to the inlet port of the first exhaust gas outlet pipe and the outlet port of the second exhaust gas outlet pipe; the mother liquor inlet pipe penetrates the lower side of the shell and extends to the upper part of the shell, and the outer wall of the mother liquor inlet pipe is sealed to the penetration point of the shell; the coil is disposed on the outer wall of the mother liquor inlet pipe and located inside the shell.

[0012] Furthermore, a plurality of evenly distributed air outlets are provided through one side of the housing; the air-cooling assembly includes a cooling fan located on the other side of the housing, a fan shroud connected to the air outlet port of the cooling fan and connected to the inner wall of the housing, and a plurality of air blowing pipes connected to the side of the fan shroud facing the coil, the plurality of air blowing pipes being evenly distributed along the length of the coil; the drive motor of the cooling fan is electrically connected to the PLC controller.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model discloses a PVC centrifugal mother liquor ozone tail gas treatment system. The air-cooled composite cooler utilizes the 20-25℃ low-temperature mother liquor in the mother liquor inlet pipe to exchange heat with the high-temperature tail gas, combined with air cooling to lower the tail gas temperature to 25-30℃, preventing catalyst activity decay and achieving energy savings. The return branch recirculates excess tail gas downstream of the gas-liquid separation unit, eliminating the need for repeated gas-liquid separation and reducing the load on the separation tank. The dual-branch decomposition unit avoids the activity decline caused by a single catalyst treating excess tail gas for extended periods, ensuring stable tail gas compliance. The dual-branch design supports switching to the backup branch during maintenance without downtime, meeting the 24-hour continuous processing requirements of PVC production. An audible and visual alarm further ensures stable operation. Attached Figure Description

[0014] Figure 1 This is a cross-sectional schematic diagram of the PVC centrifugal mother liquor ozone tail gas treatment system of this utility model. Figure 2 This is an enlarged schematic diagram of the gas-liquid separation unit of this utility model; Figure 3 This is a cross-sectional schematic diagram of the air-cooled composite cooler of this utility model.

[0015] In the diagram: 1. Centrifugal mother liquor buffer tank; 2. Ozone exhaust gas inlet pipe; 3. Mother liquor inlet pipe; 4. Air-cooled composite cooler; 5. First exhaust gas outlet pipe; 6. Gas-liquid separation unit; 7. First electric three-way valve; 8. First branch pipe; 9. Ozone decomposer; 10. Second electric three-way valve; 11. First connecting pipe; 12. Ozone concentration sensor; 13. Exhaust fan; 14. First electric valve; 15. Exhaust gas discharge pipe; 16. Return pipe; 17. Second electric valve; 18. Third electric valve. 19. Valve; 20. Primary gas-liquid separator; 21. Drain pipe; 22. Fourth electric valve; 23. Liquid level sensor; 24. Humidity sensor; 25. First outlet pipe; 26. Fifth electric valve; 27. Secondary gas-liquid separator; 28. Second branch pipe; 29. ​​Sixth electric valve; 30. Second outlet pipe; 31. Seventh electric valve; 32. Housing; 33. Air outlet; 34. Cooling fan; 35. Air hood; 36. Air blower; 37. Second exhaust gas outlet pipe; 38. Coil. Detailed Implementation

[0016] Please see Figure 1-3 An ozone exhaust gas treatment system for PVC centrifugal mother liquor includes a centrifugal mother liquor buffer tank 1, an ozone exhaust gas inlet pipe 2 connected to the upper side of the centrifugal mother liquor buffer tank 1, a mother liquor water inlet pipe 3 extending through and to the bottom of the centrifugal mother liquor buffer tank 1, and a gas-liquid separation unit 6 for gas-liquid separation of the exhaust gas. It also includes a second exhaust gas outlet pipe 36 connected to the upper side of the centrifugal mother liquor buffer tank 1, an air-cooled composite cooler 4 connected to the outlet port of the second exhaust gas outlet pipe 36 and located on the outer wall of the mother liquor water inlet pipe 3, a first exhaust gas outlet pipe 5 connected to the outlet port of the air-cooled composite cooler 4 and the inlet port of the gas-liquid separation unit 6, and a gas-liquid separation unit 6 located on the upper side of the centrifugal mother liquor buffer tank 1. The system includes a third electric valve 18 on the exhaust pipe 5, a dual-branch decomposition unit connected to the exhaust port of the gas-liquid separation unit 6, an ozone content detection and emission unit connected to the exhaust port of the dual-branch decomposition unit, a return branch connected to the exhaust main pipe of the ozone content detection and emission unit and the gas-liquid separation unit 6, a PLC controller, and an audible and visual alarm (the audible and visual alarm is installed on the side of the pipe section between the induced draft fan 13 and the first electric three-way valve 7); the air-cooled composite cooler 4, the gas-liquid separation unit 6, the third electric valve 18, the return branch, the audible and visual alarm, and the ozone content detection and emission unit are all electrically connected to the PLC controller.

[0017] This application further proposes that the gas-liquid separation unit 6 includes a primary gas-liquid separator 19 connected to the outlet port of the first exhaust gas outlet pipe 5, a humidity sensor 23 disposed on the outlet port of the primary gas-liquid separator 19, a first outlet pipe 24 connected to the outlet port of the primary gas-liquid separator 19, a fifth electric valve 25 disposed on the pipe section of the first outlet pipe 24, a second branch pipe 27 and a second outlet pipe 29 connected to the pipe wall of the first outlet pipe 24 and respectively corresponding to the inlet end and outlet end of the fifth electric valve 25, a secondary gas-liquid separator 26 connected to the inlet port of the second branch pipe 27 and the outlet port of the second outlet pipe 29, a seventh electric valve 30 disposed on the pipe section of the second outlet pipe 29, and a sixth electric valve 28 disposed on the pipe section of the second branch pipe 27; the humidity sensor 23, the fifth electric valve 25, the sixth electric valve 28, and the seventh electric valve 30 are all electrically connected to the PLC controller.

[0018] Among them, the main outlet pipe of the gas-liquid separation unit 6 refers to the first outlet pipe 24; the inlet port of the first-stage gas-liquid separator 19 is sealed and connected to the outlet port of the first exhaust gas outlet pipe 5 through a flange; a humidity sensor 23 is fixedly installed at its outlet port through a threaded interface, and the detection probe extends into the port and directly contacts the exhaust gas. At the same time, the outlet port is connected to the inlet end of the first outlet pipe 24 through a flange.

[0019] Specifically, the humidity sensor 23 monitors the humidity of the exhaust gas after the first-stage separation in real time. When the humidity is ≤5%RH (meeting the requirements of subsequent ozone decomposition), the PLC controller opens the fifth electric valve 25 and closes the sixth electric valve 28 and the seventh electric valve 30. When the humidity is >8%RH, it immediately switches to the branch circuit and deeply removes water through the secondary gas-liquid separator 26 to ensure the dryness of the exhaust gas entering the dual-branch decomposition unit and avoid water vapor affecting the catalyst activity.

[0020] This application further proposes that the outlet ports of the primary gas-liquid separator 19 and the secondary gas-liquid separator 26 are both connected to a drain pipe 20, and a liquid level sensor 22 is provided at the bottom of the outer wall of the primary gas-liquid separator 19 and the secondary gas-liquid separator 26. A fourth electric valve 21 is provided on the pipe section of the drain pipe 20, and the two liquid level sensors 22 and the two fourth electric valves 21 are all electrically connected to the PLC controller.

[0021] Both the primary gas-liquid separator 19 and the secondary gas-liquid separator 26 have pre-set water outlet ports at their bottoms. The inlet ends of the two drain pipes 20 are sealed and connected to the corresponding outlet ports of the separators via flanges. A fourth electric valve 21 is fixedly installed in the middle of the drain pipe 20 via a flange. At the same time, a liquid level sensor 22 is fixedly installed on the bottom of the outer wall of both the primary gas-liquid separator 19 and the secondary gas-liquid separator 26 (near the water outlet port) via bolts. The detection probe of the sensor penetrates the separator wall and extends into the interior of the separator, and the distance between the bottom of the probe and the bottom wall of the separator is consistent.

[0022] Specifically, the liquid level sensor 22 and the fourth electric valve 21 are linked in a one-to-one manner, which can monitor and automatically discharge the condensate in the separator in real time, avoiding the problem of condensate accumulation leading to a reduction in separator volume and a decrease in gas-liquid separation efficiency.

[0023] This application further proposes that the dual-branch decomposition unit includes a first electric three-way valve 7 connected to the outlet port of the first outlet pipe 24, two first branch pipes 8 connected to the other two interfaces of the first electric three-way valve 7, ozone decomposers 9 respectively installed on the pipe sections of the two first branch pipes 8, and a second electric three-way valve 10 connected to the outlet ports of the two first branch pipes 8. The outlet ports of the two first branch pipes 8 are respectively connected to the two non-common interfaces of the second electric three-way valve 10. The first electric three-way valve 7 and the second electric three-way valve 10 are both electrically connected to the PLC controller.

[0024] In particular, on each of the two first branch pipes 8, an ozone decomposer 9 is fixedly installed by a flange. The two ozone decomposers 9 are of the same model and specifications, and have the same amount of internal catalyst filling, to ensure that the decomposition effect is consistent when the single branch is running.

[0025] Specifically, the dual-branch layout, combined with the linkage switching of the first electric three-way valve 7 and the second electric three-way valve 10, allows the PLC controller to switch valves and activate the backup branch when the ozone decomposer 9 needs to be replaced or malfunctions, thus preventing the entire unit from shutting down and ensuring the continuity of ozone exhaust gas treatment.

[0026] This application further proposes that the ozone content detection and emission unit includes a first connecting pipe 11 connected to the common end of the second electric three-way valve 10, an ozone concentration sensor 12 and an induced draft fan 13 arranged sequentially on the pipe section of the first connecting pipe 11 along the airflow direction, an exhaust pipe 15 connected to the exhaust port of the induced draft fan 13, and a first electric valve 14 arranged on the pipe section of the exhaust pipe 15; the ozone concentration sensor 12, the drive motor of the induced draft fan 13 and the first electric valve 14 are all electrically connected to the PLC controller.

[0027] The ozone concentration sensor 12 is fixedly installed on the pipe section of the first connecting pipe 11 through a threaded interface. Its detection probe extends into the pipe and comes into direct contact with the exhaust gas to monitor the ozone concentration in real time. The air inlet of the induced draft fan 13 is sealed and connected to the air outlet of the first connecting pipe 11 through a flange to provide power for the exhaust gas transportation. Its air outlet is also connected to the air inlet of the exhaust gas pipe 15 through a flange.

[0028] This application further proposes that the return branch includes a return pipe 16 connected to the first outlet pipe 24 section and located between the outlet end of the second outlet pipe 29, a second electric valve 17 provided on the return pipe 16 section, and a one-way valve provided on the return pipe 16 section; the air inlet of the return pipe 16 is connected to the pipe wall of the exhaust pipe 15 and located between the induced draft fan 13 and the first electric valve 14.

[0029] The first connection end of the return pipe 16 is sealed and connected to the pipe section of the first outlet pipe 24 through a three-way connector, and the connection position is located between the outlet end of the second outlet pipe 29 and the inlet end of the first electric three-way valve 7, ensuring that the return exhaust gas can be directly merged into the main exhaust gas channel after water removal; the second connection end of the return pipe 16 is also sealed and connected to the pipe wall of the exhaust gas discharge pipe 15 through a three-way connector. This connection point is located between the exhaust port of the induced draft fan 13 and the inlet end of the first electric valve 14, which can directly intercept the exhaust gas exceeding the standard to be discharged.

[0030] Specifically, the linkage design between the second electric valve 17 and the PLC controller can automatically open and close according to the detection results of the ozone concentration sensor 12 without manual intervention, which not only improves the processing efficiency but also reduces the safety hazards of human contact with high-risk media.

[0031] This application further proposes that the air-cooled composite cooler 4 includes a housing 31, an air-cooling component disposed on one side of the outer wall of the housing 31, and a coil 37 connected to the inlet port of the first exhaust gas outlet pipe 5 and the outlet port of the second exhaust gas outlet pipe 36; the mother liquor inlet pipe 3 penetrates the lower side of the housing 31 and extends to the upper part of the housing 31, and the outer wall of the mother liquor inlet pipe 3 is sealed to the penetration point of the housing 31; the coil 37 is disposed on the outer wall of the mother liquor inlet pipe 3 and located inside the housing 31.

[0032] Among them, the mother liquor inlet pipe 3 passes through the pre-set opening on the lower side of the outer shell 31 in a vertical direction, and the pipe wall and the inner wall of the opening are sealed and connected by a high temperature resistant sealing ring; the coil 37 is fixed to the mother liquor inlet pipe 3 in a spiral winding manner inside the outer shell 31, and the air inlet end of the coil 37 is sealed and connected to the air outlet port of the second tail gas outlet pipe 36 through a flange, and the air outlet end is also sealed and connected to the air inlet port of the first tail gas outlet pipe 5 through a flange.

[0033] Specifically, the coil 37 is wound around the outer wall of the mother liquor inlet pipe 3, so that the high-temperature exhaust gas (40-60℃) can directly exchange heat with the low-temperature mother liquor (20-25℃) in the mother liquor inlet pipe 3, thus preventing the high-temperature exhaust gas from entering the subsequent gas-liquid separation unit 6 and ozone decomposer.

[0034] This application further proposes that a plurality of evenly distributed air outlet holes 32 are provided through one side of the outer casing 31; the air-cooling assembly includes a cooling fan 33 fixedly installed on the other side of the outer casing 31 by bolts, a fan shroud 34 connected to the air outlet port of the cooling fan 33 by a flange seal and connected to the inner wall of the outer casing 31, and a plurality of air blowing pipes 35 connected to the side of the fan shroud 34 facing the coil 37, the plurality of air blowing pipes 35 being evenly distributed along the length of the coil 37; the drive motor of the cooling fan 33 is electrically connected to the PLC controller.

[0035] Multiple air outlets 32 form an airflow discharge channel; the end of the shroud 34 away from the cooling fan 33 is fixedly connected to the inner wall of the outer casing 31 by welding.

[0036] Specifically, the cooling fan 33, the fan shroud 34, and the air duct 35 can deliver cool air to the outer wall of the coil 37 to avoid exhaust gas temperature fluctuations caused by uneven local cooling. At the same time, the air outlet 32 ​​on one side of the outer casing 31 and the cooling fan 33 on the other side form a convective airflow to accelerate the discharge of heat from the inside of the outer casing 31, preventing high temperature from affecting the activity of the catalyst in the subsequent ozone decomposer 9 and extending the service life of the catalyst.

[0037] Working process and principle: When the device is working, the PVC centrifugal mother liquor is transported to the bottom of the centrifugal mother liquor buffer tank 1 through the mother liquor inlet pipe 3. The unreacted ozone tail gas in the mother liquor is collected in the gas phase space at the top of the buffer tank 1 through the ozone tail gas inlet pipe 2. Then, the PLC controller simultaneously opens the third electric valve 18 and the cooling fan 33. The tail gas enters the coil 37 through the second tail gas outlet pipe 36. At this time, the low temperature mother liquor of 20-25℃ in the mother liquor inlet pipe 3 forms an indirect heat exchange with the coil 37. At the same time, the cold air generated by the cooling fan 33 is diverted to multiple air blowing pipes 35 through the air hood 34 and blown evenly onto the outer wall of the coil 37. The high temperature tail gas (40-60℃) is cooled down to 25-30℃ under the synergistic effect of heat exchange and air cooling. After cooling, the tail gas enters the first stage gas-liquid separator 19 of the gas-liquid separation unit 6 through the first tail gas outlet pipe 5, and the condensate entrained in the tail gas is initially separated.

[0038] During the initial separation process, the humidity sensor 23 at the outlet port of the primary gas-liquid separator 19 monitors the humidity of the exhaust gas in real time. If the detected humidity is ≤5%RH, the PLC controller directly opens the fifth electric valve 25, the first electric three-way valve 7, the second electric three-way valve 10, and the induced draft fan 13, and the exhaust gas enters the dual-branch decomposition unit through the first outlet pipe 24. If the detected humidity is >8%RH, the fifth electric valve 25 is immediately closed, and the sixth electric valve 28 and the seventh electric valve 30 are opened simultaneously. The exhaust gas is introduced into the secondary gas-liquid separator 26 through the second branch pipe 27 for deep dehydration. After dehydration, the exhaust gas flows into the first outlet pipe 24 through the second outlet pipe 29. At the same time, the liquid level sensor 22 at the bottom of the primary gas-liquid separator 19 and the secondary gas-liquid separator 26 continuously monitors the condensate level. When the liquid level reaches 300mm, the PLC controller automatically opens the fourth electric valve 21 on the corresponding drain pipe 20 to drain the water. When the liquid level drops to 50mm, the fourth electric valve 21 is automatically closed to prevent liquid residue from affecting the gas-liquid separation effect.

[0039] The exhaust gas entering the dual-branch decomposition unit is distributed by the first electric three-way valve 7 to the ozone decomposer 9 corresponding to one of the first branch pipes 8 (the ozone decomposer 9 of the other first branch pipe 8 is in standby mode). Ozone is decomposed into oxygen under the action of a catalyst. After decomposition, the exhaust gas enters the first connecting pipe 11 through the second electric three-way valve 10. The ozone concentration sensor 12 detects the exhaust gas concentration in real time. If the concentration is ≤0.02ppm, the PLC controller opens the first electric valve 14, and the exhaust gas is discharged through the exhaust pipe 15 under the suction of the induced draft fan 13, meeting the emission standards. If the concentration is >0.02ppm, the PLC controller immediately closes the first electric valve 14 and simultaneously opens the second electric valve 17. It then switches to the first branch pipe 8 corresponding to the backup ozone decomposer 9 through the linkage of the first electric three-way valve 7 and the second electric three-way valve 10. The excess exhaust gas flows back to the first outlet pipe 24 through the return pipe 16 with a one-way valve (to prevent backflow) and re-enters the dual-branch decomposition unit for secondary treatment. At the same time, the audible and visual alarm is activated to issue an abnormality warning, reminding the staff to carry out maintenance work on the faulty ozone decomposer 9 in a timely manner.

[0040] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A PVC centrifugal mother liquor ozone tail gas treatment system, comprising a centrifugal mother liquor buffer tank (1), an ozone tail gas inlet pipe (2) connected to the upper side of the centrifugal mother liquor buffer tank (1), a mother liquor water inlet pipe (3) extending through and to the bottom of the centrifugal mother liquor buffer tank (1), and a gas-liquid separation unit (6) for gas-liquid separation of the tail gas, characterized in that, It also includes a second tail gas outlet pipe (36) connected to the upper side of the centrifugal mother liquor buffer tank (1), an air-cooled composite cooler (4) connected to the outlet port of the second tail gas outlet pipe (36) and located on the outer wall of the mother liquor inlet pipe (3), a first tail gas outlet pipe (5) connected to the outlet port of the air-cooled composite cooler (4) and the inlet port of the gas-liquid separation unit (6), a third electric valve (18) located on the pipe section of the first tail gas outlet pipe (5), a dual-branch decomposition unit connected to the outlet port of the gas-liquid separation unit (6), an ozone content detection and emission unit connected to the outlet port of the dual-branch decomposition unit, a return branch connected to the main outlet pipe of the ozone content detection and emission unit and the gas-liquid separation unit (6), a PLC controller and an audible and visual alarm; the air-cooled composite cooler (4), the gas-liquid separation unit (6), the third electric valve (18), the return branch, the audible and visual alarm and the ozone content detection and emission unit are all electrically connected to the PLC controller.

2. The ozone exhaust gas treatment system according to claim 1, characterized in that, The gas-liquid separation unit (6) includes a first-stage gas-liquid separator (19) connected to the outlet port of the first exhaust gas outlet pipe (5), a humidity sensor (23) located at the outlet port of the first-stage gas-liquid separator (19), a first outlet pipe (24) connected to the outlet port of the first-stage gas-liquid separator (19), a fifth electric valve (25) located on the pipe section of the first outlet pipe (24), a second branch pipe (27) and a second outlet pipe (29) connected to the pipe wall of the first outlet pipe (24) and respectively corresponding to the inlet and outlet ends of the fifth electric valve (25), a second-stage gas-liquid separator (26) connected to the inlet port of the second branch pipe (27) and the outlet port of the second outlet pipe (29), a seventh electric valve (30) located on the pipe section of the second outlet pipe (29), and a sixth electric valve (28) located on the pipe section of the second branch pipe (27); the humidity sensor (23), the fifth electric valve (25), the sixth electric valve (28), and the seventh electric valve (30) are all electrically connected to the PLC controller.

3. The ozone exhaust gas treatment system according to claim 2, characterized in that, The outlet ports of the primary gas-liquid separator (19) and the secondary gas-liquid separator (26) are both connected to a drain pipe (20). The bottom of the outer wall of the primary gas-liquid separator (19) and the secondary gas-liquid separator (26) are equipped with a liquid level sensor (22). A fourth electric valve (21) is provided on the pipe section of the drain pipe (20). The two liquid level sensors (22) and the two fourth electric valves (21) are electrically connected to the PLC controller.

4. The ozone exhaust gas treatment system according to claim 2, characterized in that, The dual-branch decomposition unit includes a first electric three-way valve (7) connected to the outlet port of the first outlet pipe (24), two first branch pipes (8) connected to the other two interfaces of the first electric three-way valve (7), an ozone decomposer (9) respectively installed on the pipe sections of the two first branch pipes (8), and a second electric three-way valve (10) connected to the outlet ports of the two first branch pipes (8). The outlet ports of the two first branch pipes (8) are respectively connected to the two non-common interfaces of the second electric three-way valve (10). The first electric three-way valve (7) and the second electric three-way valve (10) are both electrically connected to the PLC controller.

5. The ozone exhaust gas treatment system according to claim 4, characterized in that, The ozone content detection and emission unit includes a first connecting pipe (11) connected to the common end of the second electric three-way valve (10), an ozone concentration sensor (12) and an induced draft fan (13) arranged sequentially on the pipe section of the first connecting pipe (11) along the airflow direction, an exhaust pipe (15) connected to the exhaust port of the induced draft fan (13), and a first electric valve (14) arranged on the pipe section of the exhaust pipe (15); the ozone concentration sensor (12), the drive motor of the induced draft fan (13) and the first electric valve (14) are all electrically connected to the PLC controller.

6. The ozone exhaust gas treatment system according to claim 5, characterized in that, The return branch includes a return pipe (16) connected to the first outlet pipe (24) section and located between the outlet end of the second outlet pipe (29), a second electric valve (17) provided on the return pipe (16) section, and a one-way valve provided on the return pipe (16) section; the air inlet of the return pipe (16) is connected to the pipe wall of the exhaust pipe (15) and located between the induced draft fan (13) and the first electric valve (14).

7. The ozone exhaust gas treatment system according to claim 1, characterized in that, The air-cooled composite cooler (4) includes a shell (31), an air-cooling component disposed on one side of the outer wall of the shell (31), and a coil (37) connected to the inlet port of the first exhaust gas outlet pipe (5) and the outlet port of the second exhaust gas outlet pipe (36); the mother liquor inlet pipe (3) penetrates the lower side of the shell (31) and extends to the upper part of the shell (31), and the outer wall of the mother liquor inlet pipe (3) is sealed to the penetration point of the shell (31); the coil (37) is disposed on the outer wall of the mother liquor inlet pipe (3) and located inside the shell (31).

8. The ozone exhaust gas treatment system according to claim 7, characterized in that, The outer casing (31) has a plurality of evenly distributed air outlets (32) through one side; the air-cooling assembly includes a cooling fan (33) located on the other side of the outer casing (31), a fan shroud (34) connected to the air outlet of the cooling fan (33) and connected to the inner wall of the outer casing (31), and a plurality of air blowing pipes (35) connected to the side of the fan shroud (34) facing the coil (37), and the plurality of air blowing pipes (35) are evenly distributed along the length of the coil (37); the drive motor of the cooling fan (33) is electrically connected to the PLC controller.

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