Polymerizing kettle discharged material recovery system and recovery method

Abstract

The invention belongs to the technical field of chemical production, and particularly relates to a polymeric kettle discharged material recovery system and recovery method. The polymeric kettle discharge recovery system comprises a polymeric kettle, a discharge chute A, a discharge chute B, a foam catcher, a primary condenser, a secondary condenser, a condensate tank, a polymerization inhibitor pump, a first pressure transmitter, a first recovery valve, a second recovery valve, a polymeric kettle recovery main valve, a recovery regulating valve, a flow transmitter, a discharge chute recovery main valve, a third recovery valve and a fourth recovery valve, the system comprises a first pressure transmitter, a second pressure transmitter, a high-pressure recovery valve, a third pressure transmitter, a fourth pressure transmitter, a fifth pressure transmitter and a pressure adjusting module. By adding the high-pressure recovery operation, the running time of the compressor is shortened, the energy-saving effect is remarkable, and the running cost is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, and in particular relates to a polymerization kettle discharge recovery system and a recovery method. Background Art

[0002] In the vinyl chloride polymerization process, the polymerization kettle discharge compression recovery system is an important energy consumption link. Figure 2 As shown in the figure, the DCS system controls the gas vinyl chloride recovery operation by detecting the compression recovery main pipe pressure value (PT_R104). When the pressure value is ≤300kPa, the recovery compressor starts, and the vinyl chloride gas is compressed and sent to the primary and secondary cooling systems for condensation recovery until the pressure in the discharge tank drops to 50kPa, at which time the compressor stops.

[0003] However, the existing technology has the following problems:

[0004] 1. The recovery compressor starts too early, runs for too long, and consumes high energy.

[0005] 2. Long-term operation of the compressor increases equipment loss and operating costs.

[0006] 3. The overall energy efficiency of the system is low, and the energy-saving potential of the self-pressure recovery stage cannot be fully utilized.

[0007] Therefore, improvements are urgently needed. Summary of the Invention

[0008] In response to the above-mentioned defects in the prior art, the present invention provides a polymerization kettle discharge recovery system, comprising a polymerization kettle, a discharge trough A, a discharge trough B, a foam catcher, a primary condenser, a secondary condenser, a condensate tank and an inhibitor pump, the polymerization kettle is connected to the foam catcher through a first recovery main pipe, the first recovery main pipe is connected to the second recovery main pipe, and the discharge trough A and the discharge trough B are connected to the second recovery main pipe through a first recovery branch pipe and a second recovery branch pipe respectively, the foam catcher is connected to the primary condenser through a third recovery main pipe, the primary condenser is connected to the condensate tank through a first connecting pipe, the condensate tank is connected to the secondary condenser through a second connecting pipe, and the bottom of the condensate tank is connected to a drain pipe, the top of the secondary condenser is connected to a tail drain pipe, and the inhibitor pump is connected to the third recovery main pipe through a third connecting pipe.

[0009] A first pressure transmitter is provided on the top of the polymerization kettle, and a first recovery valve, a second recovery valve, a polymerization kettle recovery main valve, a recovery regulating valve and a flow transmitter are provided in sequence on the first recovery main pipe. The recovery regulating valve is communicatively connected to the flow transmitter, and the recovery regulating valve is provided with a flow regulating module. A discharge trough recovery main valve is provided on the second recovery main pipe, and a third recovery valve and a fourth recovery valve are provided on the first recovery branch pipe and the second recovery branch pipe respectively. A second pressure transmitter and a high-pressure recovery valve are provided in sequence on the third recovery main pipe, and a third pressure transmitter and a fourth pressure transmitter are provided on the top of the discharge trough A and the discharge trough B respectively. A discharge valve is provided on the discharge pipe, and a fifth pressure transmitter and a pressure regulating module are provided on the tail discharge pipe, and the fifth pressure transmitter is communicatively connected to the pressure regulating module.

[0010] Optionally, the connection port between the second recovery main pipe and the first recovery main pipe is located between the polymerization kettle recovery main valve and the recovery regulating valve.

[0011] Optionally, the connection port between the third connecting pipe and the third recovery main pipe is located between the second pressure transmitter and the high-pressure recovery valve.

[0012] The present invention also provides a method for recovering discharged material from a polymerization reactor, comprising the following steps:

[0013] S1. Close the main recovery valve of the polymerization kettle and open the main recovery valve of the discharge chute to start recovering the vinyl chloride in the system.

[0014] S2. Select discharge trough A or discharge trough B to collect the material, and open the third recovery valve or the fourth recovery valve.

[0015] S3. Set the recovery regulating valve to an initial valve position of 50%, and increase the valve position opening at a valve position rate of 5% per second until the valve position reaches 70%.

[0016] S4. When the second pressure transmitter detects that the pressure in the third recovery main pipe is greater than 300KPa, the drain valve is opened and the inhibitor pump is started.

[0017] S5. Open the high-pressure recovery valve, set the threshold of 0.25MPa for the pressure regulating module, and start the automatic mode; set the valve position of the recovery regulating valve to 35%, and the flow regulating module will adjust the valve position according to 3000m based on the initial valve position of 35% of the recovery regulating valve. 3 The recovery speed is controlled by the set flow rate of / h.

[0018] S6. When the first pressure transmitter detects that the pressure of the polymerization kettle is less than 0.25 MPa, close the first recovery valve, the second recovery valve and the polymerization kettle recovery main valve, and open the discharge tank recovery main valve, and switch to the discharge tank recovery again.

[0019] S7. Select discharge trough A or discharge trough B to collect the material, and open the third recovery valve or the fourth recovery valve.

[0020] S8. When the third pressure transmitter or the fourth pressure transmitter detects that the pressure of the discharge trough A or the discharge trough B is less than 0.25 MPa, close the third recovery valve or the fourth recovery valve, and close the discharge trough recovery main valve.

[0021] S9: When the second pressure transmitter detects that the pressure of the third recovery main pipe is less than 250KPa, or the flow transmitter detects that the flow of the first recovery main pipe is less than 1800m 3 / h, close the high-pressure recovery valve and the recovery regulating valve.

[0022] S10: The recycling process ends.

[0023] Optionally, in steps S2 and S7, the discharge trough for receiving the material is selected based on the pressure and liquid level indicators in the discharge trough A or the discharge trough B.

[0024] Optionally, in step S3, while the recovery regulating valve is open, the gaseous vinyl chloride is defoamed by the foam trap and then recovered to the primary condenser and the secondary condenser for condensation.

[0025] Optionally, in step S5, when the stirring current of the polymerization kettle is low and the bottom valve of the polymerization kettle is closed, it is determined that the discharge of the polymerization kettle is completed, the third recovery valve VSP_R110a or the fourth recovery valve VSP_R110b, and the discharge trough recovery main valve VSP_R111 are closed, and the discharge trough A or the discharge trough B is suspended to continue collecting materials; the first recovery valve VSP_P107, the second recovery valve VSP_P109 and the polymerization kettle recovery main valve VSP_R108 are opened, and the polymerization kettle recovery is switched, and the recovery regulating valve is given a valve position of 100% to control the recovery speed.

[0026] The beneficial effects of the present invention are:

[0027] (1) Significantly reduce energy consumption: By adding high-pressure recovery operation, the compressor is no longer used during each kettle discharge, and all self-pressure recovery is used. This can save about 17 minutes of compressor operation time per kettle, and save more than 600,000 kWh of electricity each year, with significant energy-saving effects.

[0028] (2) Saving operating costs: After optimization, the compressor is no longer used during the discharge of the polymerization kettle, which can save about 380,000 yuan in electricity costs each year and reduce the compressor maintenance costs by 62,000 yuan each year, greatly reducing operating costs.

[0029] (3) Improve system efficiency: Under the premise of ensuring that the overall discharge and recovery time remains unchanged, the system operation logic is optimized and the overall efficiency of the system is improved.

[0030] (4) Extend equipment life: Reduce compressor operating time, reduce equipment loss, and extend equipment service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below with reference to the accompanying drawings and examples.

[0032] Figure 1 This is a structural schematic diagram of a polymerization kettle discharge recovery system provided by the present invention.

[0033] Figure 2 This is a structural diagram of the polymerization kettle discharge recovery system before the transformation. DETAILED DESCRIPTION

[0034] The present invention is described below in conjunction with the accompanying drawings and specific embodiments of the present invention. The description herein is only used to explain the present invention and is not intended to limit the present invention. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without creative work based on all other embodiments obtained in the present invention should be included in the scope of protection of the present invention.

[0035] Example 1

[0036] like Figure 1 As shown, an embodiment of the present invention provides a polymerization kettle discharge recovery system, including a polymerization kettle 1, a discharge trough A2, a discharge trough B3, a foam catcher 4, a primary condenser 5, a secondary condenser 6, a condensate tank 7 and an inhibitor pump PU_5F, the polymerization kettle is connected to the foam catcher through a first recovery main pipe P1, the first recovery main pipe is connected to the second recovery main pipe P2, and the discharge trough A and the discharge trough B are connected to the second recovery main pipe through a first recovery branch pipe P4 and a second recovery branch pipe P5 respectively, the foam catcher is connected to the primary condenser through a third recovery main pipe P3, the primary condenser is connected to the condensate tank through a first connecting pipe J1, the condensate tank is connected to the secondary condenser through a second connecting pipe J2, and the bottom of the condensate tank is connected to a drain pipe J5, the top of the secondary condenser is connected to a tail drain pipe J4, and the inhibitor pump is connected to the third recovery main pipe through a third connecting pipe J3.

[0037] The top of the polymerization kettle is provided with a first pressure transmitter PT_P102, and the first recovery valve VSP_P107, the second recovery valve VSP_P109, the polymerization kettle recovery valve VSP_R108, the recovery regulating valve FV_R101 and the flow transmitter FT_R101 are sequentially provided on the first recovery main pipe. The recovery regulating valve is connected to the flow transmitter, and the recovery regulating valve is provided with a flow regulating module FIC_R101. The second recovery main pipe is provided with a discharge trough recovery valve VSP_R111, and the first recovery branch pipe and the second recovery branch pipe are respectively provided with a third Recovery valve VSP_R110a and the fourth recovery valve VSP_R110b, the second pressure transmitter PT_R104 and the high-pressure recovery valve VSP_R105 are arranged on the third recovery main pipe in sequence, the third pressure transmitter PT_S101a and the fourth pressure transmitter PT_S101b are arranged on the top of the discharge trough A and the discharge trough B respectively, the discharge pipe is provided with a discharge valve VSP_VC31, the tail discharge pipe is provided with a fifth pressure transmitter PT_R105 and a pressure regulating module PIC_R105, and the fifth pressure transmitter is communicatively connected with the pressure regulating module.

[0038] In addition, the connection port between the second recovery main pipe and the first recovery main pipe is located between the polymerization kettle recovery main valve and the recovery regulating valve. The connection port between the third connecting pipe and the third recovery main pipe is located between the second pressure transmitter and the high-pressure recovery valve.

[0039] Example 2

[0040] An embodiment of the present invention provides a method for recovering discharged material from a polymerization reactor, comprising the following steps:

[0041] S1. Close the main recovery valve of the polymerization kettle and open the main recovery valve of the discharge chute to start recovering the vinyl chloride in the system.

[0042] S2. Select which discharge trough to collect the material based on the pressure and liquid level indicators in discharge trough A or discharge trough B. If the pressure and liquid level of discharge trough A are both small, open the third recovery valve for recovery.

[0043] S3. Set the initial valve position of the recovery regulating valve to 50%, and increase the valve position opening at a valve position rate of 5% per second until the valve position is opened to 70%; during the process of opening the recovery regulating valve, the gaseous vinyl chloride is defoamed in the foam trap and then recovered to the primary condenser and the secondary condenser for condensation.

[0044] S4. When the second pressure transmitter detects that the pressure in the third recovery main pipe is greater than 300KPa, the drain valve is opened and the inhibitor pump is started.

[0045] S5. Open the high-pressure recovery valve, set the threshold of 0.25MPa for the pressure regulating module, and start the automatic mode; set the valve position of the recovery regulating valve to 35%, and the flow regulating module will adjust the valve position according to 3000m based on the initial valve position of 35% of the recovery regulating valve. 3 / h set flow rate to control the recovery speed; when the stirring current of the polymerization kettle is low and the bottom valve of the polymerization kettle is closed, it is determined that the discharge of the polymerization kettle is completed, the third recovery valve and the main recovery valve of the discharge chute are closed, and the discharge chute A is suspended to continue collecting materials; the first recovery valve, the second recovery valve and the main recovery valve of the polymerization kettle are opened, and the recovery of the polymerization kettle is switched to the recovery of the polymerization kettle, and the recovery regulating valve is given a valve position of 100% to control the recovery speed.

[0046] S6. When the first pressure transmitter detects that the pressure of the polymerization kettle is less than 0.25 MPa, close the first recovery valve, the second recovery valve and the polymerization kettle recovery main valve, and open the discharge tank recovery main valve, and switch to the discharge tank recovery again.

[0047] S7. Select which discharge trough to collect the material according to the pressure and liquid level indicators in discharge trough A or discharge trough B. If the pressure and liquid level of discharge trough B are both smaller, open the fourth recovery valve to recover the material.

[0048] S8. When the fourth pressure transmitter detects that the pressure of the discharge trough B is less than 0.25 MPa, the fourth recovery valve and the main recovery valve of the discharge trough are closed.

[0049] S9: When the second pressure transmitter detects that the pressure of the third recovery main pipe is less than 250KPa, or the flow transmitter detects that the flow of the first recovery main pipe is less than 1800m 3 / h, close the high-pressure recovery valve and the recovery regulating valve.

[0050] S10: The recycling process ends.

[0051] While the embodiments of the present invention have been described above, the above description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A polymerization kettle discharge recovery system, comprising a polymerization kettle, a discharge trough A, a discharge trough B, a foam catcher, a primary condenser, a secondary condenser, a condensate tank and a polymerization inhibitor pump, characterized in that: The polymerization kettle is connected to the foam trap through a first recovery main pipe, the first recovery main pipe is connected to the second recovery main pipe, and the discharge trough A and the discharge trough B are connected to the second recovery main pipe through a first recovery branch pipe and a second recovery branch pipe respectively, the foam trap is connected to the primary condenser through a third recovery main pipe, the primary condenser is connected to the condensate tank through a first connecting pipe, the condensate tank is connected to the secondary condenser through a second connecting pipe, and the bottom of the condensate tank is connected to a drain pipe, the top of the secondary condenser is connected to a tail pipe, and the inhibitor pump is connected to the third recovery main pipe through a third connecting pipe; A first pressure transmitter is provided on the top of the polymerization kettle, and a first recovery valve, a second recovery valve, a polymerization kettle recovery main valve, a recovery regulating valve and a flow transmitter are provided in sequence on the first recovery main pipe. The recovery regulating valve is communicatively connected to the flow transmitter, and the recovery regulating valve is provided with a flow regulating module. A discharge trough recovery main valve is provided on the second recovery main pipe, and a third recovery valve and a fourth recovery valve are provided on the first recovery branch pipe and the second recovery branch pipe respectively. A second pressure transmitter and a high-pressure recovery valve are provided in sequence on the third recovery main pipe, and a third pressure transmitter and a fourth pressure transmitter are provided on the top of the discharge trough A and the discharge trough B respectively. A discharge valve is provided on the discharge pipe, and a fifth pressure transmitter and a pressure regulating module are provided on the tail discharge pipe, and the fifth pressure transmitter is communicatively connected to the pressure regulating module.

2. The polymerizer discharge recovery system according to claim 1, characterized in that: The connecting port between the second recovery main pipe and the first recovery main pipe is located between the polymerization kettle recovery main valve and the recovery regulating valve.

3. The polymerizer discharge recovery system according to claim 2, characterized in that: The connection port between the third connecting pipe and the third recovery main pipe is located between the second pressure transmitter and the high-pressure recovery valve.

4. A recovery method based on the polymerization reactor discharge recovery system according to any one of claims 1 to 3, characterized in that: The steps include: S1. Close the main recovery valve of the polymerization kettle and open the main recovery valve of the discharge tank to start recovering vinyl chloride in the system; S2. Select discharge trough A or discharge trough B to collect the material, and open the third recovery valve or the fourth recovery valve; S3. Set the recovery regulating valve to an initial valve position of 50%, and increase the valve position opening at a valve position rate of 5% per second until the valve position reaches 70%; S4. When the second pressure transmitter detects that the pressure in the third recovery main pipe is greater than 300 kPa, the drain valve is opened and the polymerization inhibitor pump is started; S5. Open the high-pressure recovery valve, set the threshold of 0.25MPa for the pressure regulating module, and start the automatic mode; set the valve position of the recovery regulating valve to 35%, and the flow regulating module will adjust the valve position according to 3000m based on the initial valve position of 35% of the recovery regulating valve. 3 / h set flow rate to control the recovery speed; S6. When the first pressure transmitter detects that the pressure of the polymerization kettle is less than 0.25 MPa, the first recovery valve, the second recovery valve and the polymerization kettle recovery main valve are closed, and the discharge tank recovery main valve is opened to switch to the discharge tank recovery again; S7, select discharge trough A or discharge trough B to collect the material, and open the third recovery valve or the fourth recovery valve; S8. When the third pressure transmitter or the fourth pressure transmitter detects that the pressure of the discharge trough A or the discharge trough B is less than 0.25 MPa, close the third recovery valve or the fourth recovery valve, and close the discharge trough recovery main valve; S9: When the second pressure transmitter detects that the pressure of the third recovery main pipe is less than 250KPa, or the flow transmitter detects that the flow of the first recovery main pipe is less than 1800m 3 / h, close the high-pressure recovery valve and the recovery regulating valve; S10: The recycling process ends.

5. The recovery method of the polymerization reactor discharge recovery system according to claim 4, characterized in that: In steps S2 and S7, the discharge trough A or the discharge trough B is selected to receive the material based on the pressure and liquid level indicators in the discharge trough A or the discharge trough B.

6. The recovery method of the polymerization reactor discharge recovery system according to claim 4, characterized in that: In step S3, while the recovery regulating valve is open, the gaseous vinyl chloride is defoamed by the foam trap and then recovered to the primary condenser and the secondary condenser for condensation.

7. The recovery method of the polymerization reactor discharge recovery system according to claim 4, characterized in that: In step S5, when the low stirring current alarm of the polymerization kettle is sounded and the bottom valve of the polymerization kettle is closed, it is determined that the discharge of the polymerization kettle is completed, the third recovery valve VSP_R110a or the fourth recovery valve VSP_R110b, and the discharge trough recovery main valve VSP_R111 are closed, and the discharge trough A or the discharge trough B is suspended to continue collecting materials; the first recovery valve VSP_P107, the second recovery valve VSP_P109 and the polymerization kettle recovery main valve VSP_R108 are opened, and the polymerization kettle recovery is switched, and the recovery regulating valve is given a valve position of 100% to control the recovery speed.

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