Self-polymerization prevention device for safety valve of polymerization kettle

Abstract

The utility model discloses an anti-self-polymerization device for a safety valve of a polymerization kettle, belongs to the technical field of safety valves of polymerization kettles, and solves the problem that a pipe orifice of the safety valve at the top of the polymerization kettle generates a self-polymerization phenomenon. The two nitrogen conveying branch pipelines are gathered to one nitrogen conveying main pipeline, and a nitrogen adjusting valve is arranged on the nitrogen conveying main pipeline; a first safety valve and a second safety valve are arranged on the two nitrogen conveying branch pipelines respectively, a first pressure transmitter and a second pressure transmitter are correspondingly connected to the first safety valve and the second safety valve respectively, and the first pressure transmitter and the second pressure transmitter are interlocked with the nitrogen adjusting valve respectively. According to the utility model, a set of automatic nitrogen charging system is merged into the top of the polymerization kettle, and the nitrogen regulating valve and the two pressure transmitters are respectively interlocked, so that when the polymerization kettle begins to react, a DCS (Distributed Control System) program can automatically start the polymerization kettle to charge nitrogen, so that a safety valve pipeline is filled with nitrogen, and the self-polymerization phenomenon is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of polymerization kettle safety valves, and particularly relates to a polymerization kettle safety valve anti-self-polymerization device. Background Art

[0002] During the PVC resin production process, VCM monomer self-aggregation in the reaction equipment (polymerizer) can seriously affect the smooth operation of the production unit. To prevent overpressure in the polymerization reactor, two safety valves are installed on top of the reactor. During the polymerization process, the pipeline from the bottom of the safety valve to the top of the reactor becomes filled with VCM monomer. The gaseous VCM monomer is more likely to self-aggregate here, forming large aggregates, which can cause pipeline blockage and affect the normal activation of the safety valve. Utility Model Content

[0003] The utility model aims to provide a device for preventing self-aggregation of a safety valve of a polymerization kettle, so as to solve the problem of self-aggregation of a safety valve pipe opening on the top of the polymerization kettle.

[0004] The technical solution of the utility model is: a polymerization kettle safety valve anti-self-polymerization device, comprising a polymerization kettle, two nitrogen delivery branch pipelines are respectively provided on the top of the polymerization kettle, the two nitrogen delivery branch pipelines are converged into a nitrogen delivery main pipeline, and a nitrogen regulating valve is provided on the nitrogen delivery main pipeline; a first safety valve and a second safety valve are respectively provided on the two nitrogen delivery branch pipelines, the first safety valve and the second safety valve are respectively connected to a first pressure transmitter and a second pressure transmitter, the first pressure transmitter and the second pressure transmitter are respectively interlocked with the nitrogen regulating valve, and a first hand valve and a second hand valve are respectively provided on the nitrogen delivery branch pipelines between the first safety valve, the second safety valve and the polymerization kettle.

[0005] As a further improvement of the present invention, when the first pressure transmitter and the second pressure transmitter detect that the pressure is greater than 0.8 MPa, the opening of the nitrogen regulating valve is reduced.

[0006] As a further improvement of the present invention, when the first pressure transmitter and the second pressure transmitter detect that the pressure is greater than 0.95 MPa, the nitrogen regulating valve is closed.

[0007] The beneficial effects of the utility model are as follows: an automatic nitrogen filling system is incorporated into the top of the polymerization kettle, the automatic nitrogen filling system consists of a nitrogen delivery pipeline, a nitrogen regulating valve and two pressure transmitters are interlocked respectively, and the pressure interlock and system timer are used to realize the self-polymerization prevention of the polymerization kettle pipe mouth. When the polymerization kettle starts to react, the DCS program automatically starts the polymerization kettle to charge with nitrogen, so that the safety valve pipeline is filled with nitrogen, thereby reducing the occurrence of self-polymerization. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1It is a schematic diagram of the overall structure of the utility model.

[0009] In the figure: 1-polymerization kettle; 2-first manual valve; 3-second manual valve; 4-first safety valve; 5-second safety valve; 6-first pressure transmitter; 7-second pressure transmitter; 8-nitrogen regulating valve; 9-nitrogen delivery branch pipeline; 10-nitrogen delivery main pipeline. DETAILED DESCRIPTION

[0010] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0011] like Figure 1 As shown, a polymerization kettle safety valve anti-self-polymerization device includes a polymerization kettle 1, two nitrogen delivery branch pipes 9 are respectively provided on the top of the polymerization kettle 1, and the two nitrogen delivery branch pipes 9 are converged into a nitrogen delivery main pipe 10, and a nitrogen regulating valve 8 is provided on the nitrogen delivery main pipe 10; a first safety valve 4 and a second safety valve 5 are respectively provided on the two nitrogen delivery branch pipes 9, and the first safety valve 4 and the second safety valve 5 are respectively connected to a first pressure transmitter 6 and a second pressure transmitter 7, and the first pressure transmitter 6 and the second pressure transmitter 7 are respectively interlocked with the nitrogen regulating valve 8, and a first manual valve 2 and a second manual valve 3 are respectively provided on the nitrogen delivery branch pipe 9 between the first safety valve 4, the second safety valve 5 and the polymerization kettle 1.

[0012] When the first pressure transmitter 6 and the second pressure transmitter 7 detect that the pressure is greater than 0.8 MPa, the opening of the nitrogen regulating valve 8 is reduced; when the first pressure transmitter 6 and the second pressure transmitter 7 detect that the pressure is greater than 0.95 MPa, the nitrogen regulating valve 8 is closed.

[0013] After entering the nitrogen delivery main pipeline 10, high-purity nitrogen is divided into two paths through a three-way nitrogen regulating valve 8, entering the nitrogen delivery branch pipeline 9 at the bottom of the first safety valve 4 and the second safety valve 5. The first pressure transmitter 6 and the second pressure transmitter 7 are interlocked with the nitrogen regulating valve 8 to ensure stable nitrogen pressure in the pipeline. After the polymerization kettle 1 is put into production, the system automatically opens the nitrogen regulating valve 8 every 120 seconds to fill the pipeline with nitrogen. When the first pressure transmitter 6 and the second pressure transmitter 7 detect a pressure greater than 0.8MPa, the pressure interlock is triggered, and the system automatically reduces the opening of the nitrogen regulating valve 8, slowing the nitrogen filling rate in the pipeline. When the first pressure transmitter 6 and the second pressure transmitter 7 detect a pressure greater than 0.95MPa, the system automatically closes the nitrogen regulating valve 8, so that the pressure in the nitrogen delivery branch pipeline 9 at the bottom of the first safety valve 4 and the second safety valve 5 is equal to or slightly greater than the pressure in the polymerization kettle 1, thereby ensuring that gaseous VCM monomer does not accumulate in this pipeline and preventing the occurrence of self-aggregation.

[0014] During normal reaction of the polymerization kettle 1, the pressure is controlled at 0.8-0.95 MPa. When the set pressure is greater than 0.95 MPa, the nitrogen regulating valve 8 is closed, which can not only ensure the safe operation of the polymerization kettle and avoid overpressure, but also ensure that the nitrogen pressure in the nitrogen filling pipeline is greater than the pressure in the polymerization kettle 1, thereby avoiding the accumulation of gas inside the polymerization kettle 1 at the bottom of the safety valve; when the set pressure is greater than 0.8 MPa, reducing the opening of the nitrogen regulating valve 8 can achieve more precise control, reduce the nitrogen filling flow in advance, and avoid overpressure due to the delayed closing of the nitrogen regulating valve 8.

[0015] The combination of the first and second safety valves 4 and 5 with the first and second manual valves 2 and 3 can first improve maintenance convenience. For example, when a safety valve requires maintenance or calibration, if the safety valve is connected to the system and there are no manual valves, the entire system must be shut down and replaced before the safety valve can be removed. This not only increases the complexity and difficulty of maintenance but may also affect production continuity. However, the installation of manual valves allows for convenient maintenance or calibration of the safety valve without affecting the entire system.

[0016] Secondly, it ensures the safe release of nitrogen from the pipeline. In some cases, the pressure may not drop immediately after the safety valve is tripped, causing the safety valve to not return to its original position. This is where the manual valve comes in handy, ensuring that pressure can still be released through the manual valve in the event of a safety valve failure, preventing equipment damage from overpressure. Finally, it prevents malfunction of the safety valve. By controlling the manual valve, the manual valve can be closed when necessary, preventing unnecessary pressure release caused by malfunctioning of the safety valve, thereby ensuring system stability and safety.

Claims

1. A polymerization kettle safety valve anti-self-polymerization device, comprising a polymerization kettle, characterized in that: Two nitrogen delivery branch pipes (9) are respectively provided on the top of the polymerization kettle (1), and the two nitrogen delivery branch pipes (9) are combined into a nitrogen delivery main pipe (10). The nitrogen delivery main pipe (10) is provided with a nitrogen regulating valve (8); a first safety valve (4) and a second safety valve (5) are respectively provided on the two nitrogen delivery branch pipes (9), and the first safety valve (4) and the second safety valve (5) are respectively connected to a first pressure transmitter (6) and a second pressure transmitter (7). The first pressure transmitter (6) and the second pressure transmitter (7) are respectively interlocked with the nitrogen regulating valve (8), and a first manual valve (2) and a second manual valve (3) are respectively provided on the nitrogen delivery branch pipes (9) between the first safety valve (4), the second safety valve (5) and the polymerization kettle (1).

2. The anti-self-polymerization device of a polymerization kettle safety valve according to claim 1, characterized in that: When the first pressure transmitter (6) and the second pressure transmitter (7) detect that the pressure is greater than 0.8 MPa, the opening of the nitrogen regulating valve (8) is reduced.

3. The device for preventing self-polymerization of a polymerization kettle safety valve according to claim 1, characterized in that: When the first pressure transmitter (6) and the second pressure transmitter (7) detect that the pressure is greater than 0.95 MPa, the nitrogen regulating valve (8) is closed.

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