Vinyl chloride gas recovery device

Abstract

The utility model discloses a vinyl chloride gas recovery device which comprises a polymerization kettle, the polymerization kettle is communicated with a material receiving groove through a pipeline, the material receiving groove is communicated with a recovery monomer buffer tank through a pipeline, the recovery monomer buffer tank is communicated with a water ring compressor through a pipeline, and the water ring compressor is communicated with a steam-water separator through a pipeline. The steam-water separator is communicated with a monomer recovery condenser through a pipeline, the monomer recovery condenser is communicated with a monomer liquid seal through a pipeline, and the monomer liquid seal is communicated with a monomer recovery tank through a pipeline; and an interlocking control device is also arranged between the recovery monomer buffer tank and the water ring compressor. The vinyl chloride gas recovery device provided by the utility model solves the problems that in the prior art, an operator frequently operates a recovery process, a recovery system is easy to explode after negative pressure occurs, and the energy consumption of equipment is high due to continuous full-load operation of a water ring compressor.

Description

Technical Field

[0001] The utility model belongs to the technical field of polyvinyl chloride production, and in particular relates to a vinyl chloride gas recovery device. Background Art

[0002] The main work of the polymerization process of the PVC device is to generate PVC resin by reacting vinyl chloride monomer in a polymerization kettle. Generally, after the reaction in the polymerization kettle, there is still 15% to 18% residual vinyl chloride that has not participated in the reaction. This part of vinyl chloride gas needs to be recycled. In the conventional recovery process, because the feeding and discharging operation of the polymerization kettle is an intermittent process operation, and the polymerization recovery system is a continuous process operation, when the polymerization kettle does not discharge, the water ring compressor will continue to operate at full load, which will cause the compressor inlet pipeline and equipment to be in a low pressure or negative pressure state. Generally, the operator will open the compressor outlet reflux regulating valve to balance the system pressure to prevent the recovery system from forming a negative pressure. If air enters the system, an explosive environment will be formed, which has a great safety hazard. Therefore, the existing recovery process requires operators to operate frequently, and the recovery system will also have the safety hazard of negative pressure. At the same time, the continuous full-load operation of the water ring compressor will also lead to high energy consumption of the equipment. Utility Model Content

[0003] The utility model aims to provide a vinyl chloride gas recovery device, which solves the problems of frequent operation of operators in the existing recovery process in the prior art, explosion caused by negative pressure in the recovery system, and high energy consumption of the equipment caused by continuous full-load operation of the water ring compressor.

[0004] The technical scheme adopted by the utility model is that the vinyl chloride gas recovery device comprises a polymerization kettle 1, the polymerization kettle 1 is connected with a material receiving tank 2 through a pipeline, the material receiving tank 2 is connected with a recovery monomer buffer tank 3 through a pipeline, the recovery monomer buffer tank 3 is connected with a water ring compressor 4 through a pipeline, the water ring compressor 4 is connected with a steam-water separator 5 through a pipeline, the steam-water separator 5 is connected with a recovery monomer condenser 6 through a pipeline, the recovery monomer condenser 6 is connected with a monomer liquid seal 7 through a pipeline, and the monomer liquid seal 7 is connected with a monomer recovery tank 8 through a pipeline;

[0005] An interlocking control device is also provided between the monomer recovery buffer tank 3 and the water ring compressor 4 .

[0006] The utility model is also characterized in that:

[0007] The interlocking control device includes a DCS control system 11, the recovery monomer buffer tank 3 is provided with a pressure transmitter 10, the pressure transmitter 10 is connected to the DCS control system 11 through a signal cable, the DCS control system 11 is connected to a frequency converter 12 through a line, the frequency converter 12 is connected to a variable frequency power supply 13 through a line, and a circuit breaker 14 is provided on the line between the frequency converter 12 and the variable frequency power supply 13;

[0008] The water ring compressor 4 is connected to a compressor motor 9 via a speed reducer, and the compressor motor 9 is connected to a frequency converter 12 via a three-phase power cable. A contactor 15 is provided on the three-phase power cable between the compressor motor 9 and the frequency converter 12 .

[0009] The maximum frequency setting limit of inverter 12 is 50Hz and the minimum frequency setting limit is 20Hz.

[0010] The interlocking pressure of the recovery monomer buffer tank 3 is set to 0.1 MPa.

[0011] The variable frequency power supply 13 is a 380V power supply.

[0012] A stirring device is provided in the polymerization kettle 1.

[0013] The beneficial effects of the utility model are:

[0014] (1) The utility model recovery device can adjust the frequency of the water ring compressor inverter according to the inlet pressure of the water ring compressor by setting an interlocking control device between the pressure transmitter and the motor inverter, thereby avoiding negative pressure in the vinyl chloride recovery system, thereby forming an explosive environment and improving the recovery safety;

[0015] (2) The recycling device of the utility model can realize automatic frequency adjustment, reduce the operation frequency of the personnel on duty, and reduce the labor intensity of the personnel on duty. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the recycling and placement structure of the utility model;

[0017] Figure 2 It is a schematic diagram of frequency conversion control of a recycling and placing water ring compressor of the utility model.

[0018] In the figure, 1. polymerization kettle, 2. receiving tank, 3. monomer recovery buffer tank, 4. water ring compressor, 5. steam-water separator, 6. monomer recovery condenser, 7. monomer liquid seal, 8. monomer recovery tank, 9. compressor motor, 10. pressure transmitter, 11. DCS control system, 12. frequency converter, 13. variable frequency power supply, 14. circuit breaker, 15. contactor. DETAILED DESCRIPTION

[0019] The utility model is described in detail below with reference to the accompanying drawings and specific implementation modes.

[0020] Vinyl chloride gas recovery unit, such as Figure 1As shown, it includes a polymerization kettle 1, in which a stirring device is arranged, which can evenly stir the vinyl chloride monomer in the polymerization kettle 1, the polymerization kettle 1 is connected with a material receiving tank 2 through a pipeline, the material receiving tank 2 is connected with a monomer recovery buffer tank 3 through a pipeline, the monomer recovery buffer tank 3 is connected with a water ring compressor 4 through a pipeline, the water ring compressor 4 is connected with a steam-water separator 5 through a pipeline, the steam-water separator 5 is connected with a monomer recovery condenser 6 through a pipeline, the monomer recovery condenser 6 is connected with a monomer liquid seal 7 through a pipeline, and the monomer liquid seal 7 is connected with a monomer recovery tank 8 through a pipeline.

[0021] Vinyl chloride monomer is reacted in a polymerization kettle 1 to generate PVC resin slurry. After the polymerization reaction, 15% to 18% of residual vinyl chloride still remains unreacted. The generated PVC resin slurry and residual vinyl chloride gas are transported by the polymerization kettle 1 to a receiving tank 2 by self-pressure. Then, the vinyl chloride gas in the receiving tank 2 is recovered to a steam-water separator 5 by a water ring compressor 4 through a monomer recovery buffer tank 3. Then, the vinyl chloride gas is transported to a monomer recovery tank 8 through a monomer recovery condenser 6 and a monomer liquid seal 7, thereby completing efficient recovery of the vinyl chloride gas.

[0022] An interlocking control device is also provided between the monomer recovery buffer tank 3 and the water ring compressor 4. Specifically, Figure 2 As shown, the interlocking control device includes a DCS control system 11, and the recovery monomer buffer tank 3 is provided with a pressure transmitter 10, which is connected to the DCS control system 11 through a signal cable, and the DCS control system 11 is connected to a frequency converter 12 through a line, and the DCS control system adjusts the frequency of the frequency converter through the signal cable PID to realize the frequency modulation control of the water ring compressor motor, and the frequency converter 12 is connected to a variable frequency power supply 13 through a line, wherein the variable frequency power supply 13 is a 380V power supply, and a circuit breaker 14 is provided on the line between the frequency converter 12 and the variable frequency power supply 13;

[0023] The water ring compressor 4 is connected to a compressor motor 9 via a speed reducer, and the compressor motor 9 is connected to a frequency converter 12 via a three-phase power cable. A contactor 15 is provided on the three-phase power cable between the compressor motor 9 and the frequency converter 12 to start and stop the motor.

[0024] The upper limit of the frequency setting of the frequency converter 12 is 50Hz, the lower limit is 20Hz, and the interlocking pressure of the pressure setting of the recovery monomer buffer tank 3 is 0.1MPa.

[0025] Operation principle: The pressure transmitter on the recovery monomer buffer tank 3 monitors the inlet pressure of the water ring compressor 4 in real time, and transmits the pressure signal to the DCS control system 11. The pressure signal received by the DCS control system 11 is compared with the preset pressure setting value (0.1MPa). If the inlet pressure of the water ring compressor 4 is lower than 0.1MPa, the DCS control system 11 will issue a command to the frequency converter 12 to reduce the output frequency of the frequency converter 12, thereby reducing the speed of the water ring compressor 4 and reducing the air intake of the water ring compressor 4; on the contrary, if the inlet pressure of the water ring compressor 4 is higher than 0.1MPa, the DCS control system 11 will instruct the frequency converter 12 to increase the output frequency, so that the speed of the water ring compressor 4 is increased and the air intake is increased. Through this real-time monitoring and adjustment, the stable control of the inlet pressure of the water ring compressor 4 is achieved, ensuring that the system operates in a safe, stable and efficient state.

[0026] During operation, when the polymerization kettle 1 is discharging material, the pressure at the inlet of the water ring compressor 4 (i.e., the monomer recovery buffer tank 3) will continue to rise and exceed 0.1MPa. At this time, the interlocking control device corresponds to the frequency converter frequency of the water ring compressor 4 of 50Hz, so as to increase the operating load of the water ring compressor 4 and increase the pumping rate; when the polymerization kettle 1 is not discharging material, the pressure at the inlet of the water ring compressor 4 (monomer recovery buffer tank 3) will continue to decrease and be lower than 0.1MPa. At this time, the interlocking control device corresponds to the frequency converter frequency of the water ring compressor 4 of 20Hz, which reduces the operating load of the water ring compressor 4 and reduces the pumping rate, thereby stabilizing the recovery system pressure and reducing the power consumption of the water ring compressor.

[0027] Example 1

[0028] Vinyl chloride gas recovery unit, such as Figure 1 As shown, it includes a polymerization kettle 1, in which a stirring device is arranged, which can evenly stir the vinyl chloride monomer in the polymerization kettle 1, the polymerization kettle 1 is connected with a material receiving tank 2 through a pipeline, the material receiving tank 2 is connected with a monomer recovery buffer tank 3 through a pipeline, the monomer recovery buffer tank 3 is connected with a water ring compressor 4 through a pipeline, the water ring compressor 4 is connected with a steam-water separator 5 through a pipeline, the steam-water separator 5 is connected with a monomer recovery condenser 6 through a pipeline, the monomer recovery condenser 6 is connected with a monomer liquid seal 7 through a pipeline, and the monomer liquid seal 7 is connected with a monomer recovery tank 8 through a pipeline.

[0029] Vinyl chloride monomer is reacted in a polymerization kettle 1 to generate PVC resin slurry. After the polymerization reaction, 15% to 18% of residual vinyl chloride still remains unreacted. The generated PVC resin slurry and residual vinyl chloride gas are transported by the polymerization kettle 1 to a receiving tank 2 by self-pressure. Then, the vinyl chloride gas in the receiving tank 2 is recovered to a steam-water separator 5 by a water ring compressor 4 through a monomer recovery buffer tank 3. Then, the vinyl chloride gas is transported to a monomer recovery tank 8 through a monomer recovery condenser 6 and a monomer liquid seal 7, thereby completing efficient recovery of the vinyl chloride gas.

[0030] Example 2

[0031] Vinyl chloride gas recovery unit, such as Figure 1 As shown, it includes a polymerization kettle 1, the polymerization kettle 1 is connected to a material receiving tank 2 through a pipeline, the material receiving tank 2 is connected to a monomer recovery buffer tank 3 through a pipeline, the monomer recovery buffer tank 3 is connected to a water ring compressor 4 through a pipeline, the water ring compressor 4 is connected to a steam-water separator 5 through a pipeline, the steam-water separator 5 is connected to a monomer recovery condenser 6 through a pipeline, the monomer recovery condenser 6 is connected to a monomer liquid seal 7 through a pipeline, and the monomer liquid seal 7 is connected to a monomer recovery tank 8 through a pipeline.

[0032] An interlocking control device is also provided between the monomer recovery buffer tank 3 and the water ring compressor 4. Specifically, Figure 2 As shown, the interlocking control device includes a DCS control system 11, and the recovery monomer buffer tank 3 is provided with a pressure transmitter 10, which is connected to the DCS control system 11 through a signal cable, and the DCS control system 11 is connected to a frequency converter 12 through a line, and the DCS control system adjusts the frequency of the frequency converter through the signal cable PID to realize the frequency modulation control of the water ring compressor motor, and the frequency converter 12 is connected to a variable frequency power supply 13 through a line, wherein the variable frequency power supply 13 is a 380V power supply, and a circuit breaker 14 is provided on the line between the frequency converter 12 and the variable frequency power supply 13;

[0033] The water ring compressor 4 is connected to a compressor motor 9 via a speed reducer, and the compressor motor 9 is connected to a frequency converter 12 via a three-phase power cable. A contactor 15 is provided on the three-phase power cable between the compressor motor 9 and the frequency converter 12 to start and stop the motor.

[0034] The upper limit of the frequency setting of the frequency converter 12 is 50Hz, the lower limit is 20Hz, and the interlocking pressure of the pressure setting of the recovery monomer buffer tank 3 is 0.1MPa.

[0035] Operation principle: The pressure transmitter 10 on the recovery monomer buffer tank 3 monitors the inlet pressure of the water ring compressor 4 in real time, and transmits the pressure signal to the DCS control system 11. The pressure signal received by the DCS control system 11 is compared with the preset pressure setting value (0.1MPa). If the inlet pressure of the water ring compressor 4 is lower than 0.1MPa, the DCS control system 11 will issue a command to the frequency converter 12 to reduce the output frequency of the frequency converter 12, thereby reducing the speed of the water ring compressor 4 and reducing the suction volume of the water ring compressor 4; on the contrary, if the inlet pressure of the water ring compressor 4 is higher than 0.1MPa, the DCS control system 11 will instruct the frequency converter 12 to increase the output frequency, so that the speed of the water ring compressor 4 is increased and the suction volume is increased. Through this real-time monitoring and adjustment, the stable control of the inlet pressure of the water ring compressor 4 is achieved, ensuring that the system operates in a safe, stable and efficient state.

[0036] Example 3

[0037] The method for recovering vinyl chloride using a vinyl chloride gas recovery device comprises the following specific steps:

[0038] Vinyl chloride monomer is reacted in a polymerization kettle 1 to generate PVC resin slurry. After the polymerization reaction, 15% to 18% of residual vinyl chloride still remains unreacted. The generated PVC resin slurry and residual vinyl chloride gas are transported by the polymerization kettle 1 to a receiving tank 2 by self-pressure. Then, the vinyl chloride gas in the receiving tank 2 is recovered to a steam-water separator 5 by a water ring compressor 4 through a monomer recovery buffer tank 3. Then, the vinyl chloride gas is transported to a monomer recovery tank 8 through a monomer recovery condenser 6 and a monomer liquid seal 7, thereby completing efficient recovery of the vinyl chloride gas.

[0039] During operation, when the polymerization kettle 1 is discharging material, the pressure at the inlet of the water ring compressor 4 (i.e., the monomer recovery buffer tank 3) will continue to rise and exceed 0.1MPa. At this time, the interlocking control device corresponds to the frequency converter frequency of the water ring compressor 4 of 50Hz, so as to increase the operating load of the water ring compressor 4 and increase the pumping rate; when the polymerization kettle 1 is not discharging material, the pressure at the inlet of the water ring compressor 4 (monomer recovery buffer tank 3) will continue to decrease and be lower than 0.1MPa. At this time, the interlocking control device corresponds to the frequency converter frequency of the water ring compressor 4 of 20Hz, which reduces the operating load of the water ring compressor 4 and reduces the pumping rate, thereby stabilizing the recovery system pressure and reducing the power consumption of the water ring compressor.

Claims

1. Vinyl chloride gas recovery device, characterized in that: The invention comprises a polymerization kettle (1), wherein the polymerization kettle (1) is connected to a material receiving tank (2) via a pipeline, the material receiving tank (2) is connected to a monomer recovery buffer tank (3) via a pipeline, the monomer recovery buffer tank (3) is connected to a water ring compressor (4) via a pipeline, the water ring compressor (4) is connected to a steam-water separator (5) via a pipeline, the steam-water separator (5) is connected to a monomer recovery condenser (6) via a pipeline, the monomer recovery condenser (6) is connected to a monomer liquid seal (7) via a pipeline, and the monomer liquid seal (7) is connected to a monomer recovery tank (8) via a pipeline; An interlocking control device is also provided between the monomer recovery buffer tank (3) and the water ring compressor (4).

2. The vinyl chloride gas recovery device according to claim 1, characterized in that: The interlocking control device comprises a DCS control system (11); the monomer recovery buffer tank (3) is provided with a pressure transmitter (10); the pressure transmitter (10) is connected to the DCS control system (11) via a signal cable; the DCS control system (11) is connected to a frequency converter (12) via a line; the frequency converter (12) is connected to a variable frequency power supply (13) via a line; and a circuit breaker (14) is provided on the line between the frequency converter (12) and the variable frequency power supply (13); The water ring compressor (4) is connected to a compressor motor (9) via a reducer, and the compressor motor (9) is connected to a frequency converter (12) via a three-phase power cable. A contactor (15) is provided on the three-phase power cable between the compressor motor (9) and the frequency converter (12).

3. The vinyl chloride gas recovery device according to claim 2, characterized in that: The frequency of the frequency converter (12) is set at a maximum limit of 50 Hz and a minimum limit of 20 Hz.

4. The vinyl chloride gas recovery device according to claim 3, characterized in that: The pressure setting interlocking pressure of the monomer recovery buffer tank (3) is 0.1 MPa.

5. The vinyl chloride gas recovery device according to claim 2, characterized in that: The variable frequency power supply (13) is a 380V power supply.

6. The vinyl chloride gas recovery device according to claim 1, characterized in that: The polymerization kettle (1) is provided with a stirring device.

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