System for reducing mechanical cleaning times of easily-blocked valve and process method thereof

Abstract

The invention discloses a system for reducing the number of mechanical cleaning times of an easily-blocked valve and a process method thereof, the left end and the right end of a line A are respectively connected with a reactor, the line A is provided with an HV1 valve, an LV1 control valve, a pressure release valve and an HV2 valve, and the line A is connected with a hot solvent flushing system; one end of the line B is connected to the inlet end of the HV1 valve, the other end of the line B is connected to the outlet end of the HV2 valve, the line B is connected with the HV5 valve, the pressure release valve, the LV2 control valve and the HV6 valve, the line A between the HV1 valve and the LV1 control valve is connected with a first pipeline with the HV4 valve, the line B between the HV5 valve and the LV2 control valve is connected with a second pipeline with the HV8 valve, and the first pipeline and the second pipeline are connected with a solvent recovery tank after being converged. A liquid level control valve is arranged in the reactor, and the LV1 control valve and the LV2 control valve can be connected with the liquid level control valve in a cascade manner, so that the device has the technical characteristics of preventing the regulating valve from being blocked, reducing the maintenance operation of the device, prolonging the long-period operation of the device and the like.

Description

Technical Field

[0001] The present invention relates to a system and a process method thereof, and more specifically, to a system and a process method thereof for reducing the number of mechanical cleaning times of easily blocked valves, and belongs to the field of petrochemical industry. Background Art

[0002] The key breakthrough directions for the development of the petroleum and chemical industry include key technologies such as high-end polyolefins, high-carbon α-olefin comonomers (C6, C8), and metallocene catalysts. However, due to the particularity of the high-carbon α-olefin reaction, the reaction system will inevitably produce polymers. Therefore, how to reduce the polymers in the system and efficiently clean up the polymers in the easily blocked areas is the focus of the current breakthrough.

[0003] At present, the main method is to set a filter in front of the regulating valve. However, even if a filter is set in front of the regulating valve, it cannot be completely filtered due to the particularity of the reaction materials. In addition, the diameter of the regulating valve at the reactor outlet is small, and the material is throttled and depressurized when passing through the regulating valve, so the regulating valve will often be blocked. When the regulating valve is blocked, cleaning the regulating valve is very time-consuming and labor-intensive. When the reaction conditions are not ideal, the reaction outlet regulating valve will not be switched and cleaned in time, which will cause the device to be forced to shut down. The longer the cutting time, the greater the difficulty of cleaning the polymer cooling. Since the regulating valve cannot be cleaned in time during normal production, the spare line regulating valve is replaced with a ball valve for manual control, but manual control is difficult to adjust, and the on-site hand valve cannot be left unattended, which greatly increases the labor cost and the risk of misoperation. Summary of the invention

[0004] In order to solve the above-mentioned problems of the prior art, the present invention provides a system and a process method for reducing the number of mechanical cleaning times of easily blocked valves, which have the technical characteristics of preventing control valves from being blocked, reducing equipment inspection and maintenance work, and extending the long-term operation of the equipment.

[0005] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0006] The present invention discloses a system for reducing the number of mechanical cleaning times of easily blocked valves, comprising an A line and a B line laid in a pipeline manner, wherein the left and right ends of the A line are respectively connected to a reactor and a downstream system, and the A line is sequentially connected to an HV1 valve, an LV1 control valve, a pressure relief valve equipped with a remote pressure gauge PZT1, and an HV2 valve, and a hot solvent flushing system is connected to the A line between the pressure relief valve equipped with a remote pressure gauge PZT1 and the HV2 valve;

[0007] One end of the B line is connected to the inlet end of the HV1 valve, and the other end of the B line is connected to the outlet end of the HV2 valve. The B line is sequentially connected with the HV5 valve, the pressure relief valve equipped with the remote pressure gauge PZT2, the LV2 control valve, and the HV6 valve. The A line between the HV1 valve and the LV1 control valve is connected to the No. 1 pipeline with the HV4 valve. The B line between the HV5 valve and the LV2 control valve is connected to the No. 2 pipeline with the HV8 valve. The No. 1 pipeline and the No. 2 pipeline are connected to the solvent recovery tank after being combined;

[0008] The hot solvent flushing system includes a hot solvent recovery tank, which is connected to pipeline No. 3 with a remote flow meter FI. The hot solvent flushing system is connected to line A through pipeline No. 3. Pipeline No. 3 is also connected to an HV3 valve. The inlet end of the HV3 valve is connected to pipeline No. 4. Pipeline No. 4 is connected to the pressure relief valve equipped with a pressure test PZT2 and line B between the HV6 valve. The pipeline No. 4 is connected to an HV7 valve. A liquid level control valve is provided in the reactor, and the LV1 control valve and the LV2 control valve can be connected in series with the liquid level control valve.

[0009] Preferably, the LV1 control valve, LV1 control valve, pressure relief valve, HV1 valve, HV2 valve, HV3 valve, HV4 valve, HV5 valve, HV6 valve, HV7 valve, and HV8 valve are all electronically controlled valves connected by communication, and also include a DCS system connected to the remote pressure gauge PZT1, remote pressure gauge PZT2, remote flowmeter FI and each valve.

[0010] The present invention discloses a process method for reducing the number of mechanical cleaning times of easily blocked valves, and the process method comprises:

[0011] 1) Under normal operating conditions, the HV1 valve and HV2 valve in line A are opened, the HV3 valve and HV4 valve are closed, and the LV1 control valve is connected in series with the liquid level control valve to realize automatic control of the liquid level; under normal operating conditions, the liquid level in the reactor is controlled at 50±5%, the opening of the LV1 control valve is 55±3%, and the reactor pressure is the pressure PI, which is set according to actual needs. The reactor pressure is set by the remote pressure sensor in the reactor; the HV5 valve, HV6 valve, HV7 valve, and HV8 valve in line B are closed, and the LV2 valve is opened to serve as a backup switching line;

[0012] 2) When the opening of the LV1 control valve is opened to more than 58%, the liquid level in the reactor continues to rise above the preset value, and the value of the remote pressure gauge PZT1 drops, the alarm is triggered, the delay is set to 15S, and the line is switched to B;

[0013] When putting Line B into use, first close the LV2 control valve to 0%, open the HV5 valve and HV6 valve, confirm that the HV5 valve and HV6 valve are open, slowly open the LV2 control valve, and set the opening OP at 0.2% / time, and set the climbing abnormal alarm according to actual needs;

[0014] 3) Cut out line A: When line B is in normal excess, the liquid level in the reactor drops, and the LV1 control valve is gradually closed. When the OP of the LV1 control valve is consistent with that of the LV2 control valve, the LV2 control valve is connected in series with the liquid level control valve in the reactor. After a delay of 10 seconds, when the liquid level in the reactor is stable, the LV1 control valve is disconnected in series with the liquid level control valve in the reactor, and the LV1 control valve is slowly closed at an opening OP of 0.2% / time, and the abnormal climbing alarm is set according to actual needs until LV1 is closed to 0%;

[0015] 4) When the LV1 control valve is closed to 0%, the reaction liquid level in the reactor does not rise, and the LV2 control valve opening OP is the same as the LV1 control valve opening OP, it is confirmed that the B line is put into use normally;

[0016] 5) Isolate line A: close HV1 valve and HV2 valve;

[0017] 6) Confirm the hot solvent pressure and temperature in the hot solvent recovery tank. If the pressure and temperature of the hot solvent recovery tank reaches the preset required value, perform pressure relief stage 1, open the HV4 valve to 25%, open the LV1 valve, and release the pipeline pressure PZT1 of the pressure relief valve equipped with the remote pressure gauge PZT1 to 30% of the normal pipeline pressure PZT1 pressure; in the pressure relief stage 2, release the pipeline pressure PZT1 solvent pressure of the pressure relief valve equipped with the remote pressure gauge PZT1 to the pressure of the solvent buffer tank, close the HV4 valve, and the pressure relief is completed;

[0018] 7) Intermittent hot washing of line A: Open the HV3 valve and observe whether the flow of the remote flow meter FI is normal. After the pressure rises to the preset hot washing oil pressure, refer to step 6) for the pipeline pressure relief process and repeat this flushing process 3 times;

[0019] 8) Continuous hot washing of line A: Open valves HV3 and HV4, confirm that the remote flow meter FI is normal, and continuously flush with hot solvent for 20 minutes. If the hot solvent flow remains normal, it is judged that the hot washing of each valve in line A is completed;

[0020] 9) Close the HV4 valve, wait for the remote pressure gauge PZT1 pressure to reach the system pressure during normal production, and then close the HV3 valve. At this time, line A is in normal standby after hot washing.

[0021] Preferably, if line B operates abnormally, the same method as steps 1) to 9) is adopted to switch from line B to line A.

[0022] Beneficial effect: The present invention foresees the problem of valve blockage in advance, improves the degree of automation of the device, reduces the number of times the valve machinery needs to be opened for inspection and clearing to a certain extent, and reduces the risk of valve damage. Through this optimization, it can effectively avoid the situation where the system loses control and is unable to discharge materials and is forced to stop working due to the blockage of the regulating valve, thereby providing guarantee for the long-term production of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a system principle block diagram of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0025] The present invention adds a hot solvent backwashing line (hot solvent flushing system) in front of the regulating valve, and regularly switches the regulating valve according to the opening of the regulating valve to perform hot solvent backwashing, thereby preventing the regulating valve from being blocked, increasing the inspection and maintenance work of the device, and affecting the long-term operation of the device.

[0026] Design a hot solvent backwashing program control for easily blocked regulating valves. According to the opening of the regulating valves in actual production, automatic backwashing of each valve at the reactor discharge is achieved through the existing DCS system.

[0027] DCS system: that is, distributed control system is based on microprocessor, which is a new generation of instrument control system that adopts the design principles of decentralized control functions, centralized display operation, and taking into account both division and autonomy and comprehensive coordination.

[0028] like Figure 1 The figure shows a specific embodiment of a system for reducing the number of mechanical cleaning times of easily blocked valves and a process method thereof, wherein a system for reducing the number of mechanical cleaning times of easily blocked valves comprises a line A and a line B laid in a pipeline manner, the left and right ends of the line A are respectively connected to a reactor and a downstream system, the line A is sequentially connected to an HV1 valve, a LV1 control valve, a pressure relief valve equipped with a remote pressure gauge PZT1, and an HV2 valve, and a hot solvent flushing system is connected to the line A between the pressure relief valve equipped with a remote pressure gauge PZT1 and the HV2 valve;

[0029] One end of the B line is connected to the inlet end of the HV1 valve, and the other end of the B line is connected to the outlet end of the HV2 valve. The B line is sequentially connected with the HV5 valve, the pressure relief valve equipped with the remote pressure gauge PZT2, the LV2 control valve, and the HV6 valve. The A line between the HV1 valve and the LV1 control valve is connected to the No. 1 pipeline with the HV4 valve. The B line between the HV5 valve and the LV2 control valve is connected to the No. 2 pipeline with the HV8 valve. The No. 1 pipeline and the No. 2 pipeline are connected to the solvent recovery tank after being combined;

[0030] The hot solvent flushing system includes a hot solvent recovery tank, which is connected to the No. 3 pipeline with a remote flowmeter FI. The hot solvent flushing system is connected to the A line through the No. 3 pipeline. The No. 3 pipeline is also connected to the HV3 valve. The inlet end of the HV3 valve is connected to the No. 4 pipeline. The No. 4 pipeline is connected to the pressure relief valve equipped with a pressure test PZT2 and the B line between the HV6 valve. The No. 4 pipeline is connected to the HV7 valve. A liquid level control valve is provided in the reactor. The LV1 control valve and the LV2 control valve can be connected in series with the liquid level control valve. The LV1 control valve, the LV1 control valve, the pressure relief valve, the HV1 valve, the HV2 valve, the HV3 valve, the HV4 valve, the HV5 valve, the HV6 valve, the HV7 valve, and the HV8 valve are all electronically controlled valves connected by communication, and also include a DCS system connected to the remote pressure gauge PZT1, the remote pressure gauge PZT2, the remote flowmeter FI and each valve.

[0031] Using a system for reducing the number of mechanical cleaning times of easily blocked valves in the present application, a specific process method includes:

[0032] 1) Under normal operating conditions, the HV1 valve and HV2 valve in line A are opened, the HV3 valve and HV4 valve are closed, and the LV1 control valve is connected in series with the liquid level control valve to realize automatic control of the liquid level; under normal operating conditions, the liquid level in the reactor is controlled at 50±5%, the opening of the LV1 control valve is 55±3%, and the reactor pressure is the pressure PI, which is set according to actual needs. The reactor pressure is set by the remote pressure sensor in the reactor; the HV5 valve, HV6 valve, HV7 valve, and HV8 valve in line B are closed, and the LV2 valve is opened to serve as a backup switching line;

[0033] 2) When the LV1 control valve is opened to more than 65% (it can be triggered according to the actual setting, or lower than the minimum setting value, and the liquid level continues to drop), the reactor liquid level continues to rise above the preset value of 60%, and the value of the remote pressure gauge PZT1 drops, the alarm is triggered, the delay is set to 15S, and the line is switched to B;

[0034] When putting Line B into use, first close the LV2 control valve to 0%, open the HV5 valve and HV6 valve, confirm that the HV5 valve and HV6 valve are open, slowly open the LV2 control valve, and set the opening OP at 0.2% / time, and set the climbing abnormal alarm according to actual needs (set the climbing speed, which can be adjusted according to actual conditions, slowly control the valve opening speed, and set the climbing abnormal alarm);

[0035] 3) Cut out line A: When line B is in normal excess, the liquid level in the reactor decreases, and the LV1 control valve is gradually closed. When the OP of the LV1 control valve is consistent with that of the LV2 control valve, the LV2 control valve is connected in series with the liquid level control valve in the reactor. After a delay of 10 seconds, the LV1 control valve is disconnected from the liquid level control valve in the reactor in series, and the LV1 control valve is slowly closed at an opening OP of 0.2% / time, and the climbing abnormal alarm is set according to actual needs (the climbing speed is set, which can be adjusted according to actual conditions, the valve closing speed is slowly controlled, and the climbing abnormal alarm is set), until LV1 is closed to 0%;

[0036] 4) When the LV1 control valve is closed to 0%, the reaction liquid level in the reactor does not rise, and the LV2 control valve opening OP is the same as the LV1 control valve opening OP, it is confirmed that the B line is put into use normally;

[0037] 5) Isolate line A: close HV1 valve and HV2 valve;

[0038] 6) Confirm the hot solvent pressure and temperature in the hot solvent recovery tank. If the pressure and temperature of the hot solvent recovery tank reaches the preset required value, perform pressure relief stage 1, open the HV4 valve to 25%, open the LV1 valve, and release the pipeline pressure PZT1 of the pressure relief valve equipped with the remote pressure gauge PZT1 to 30% of the normal pipeline pressure PZT1 pressure; in the pressure relief stage 2, release the pipeline pressure PZT1 solvent pressure of the pressure relief valve equipped with the remote pressure gauge PZT1 to the pressure of the solvent buffer tank, close the HV4 valve, and the pressure relief is completed;

[0039] 7) Intermittent hot washing of line A: Open the HV3 valve and observe whether the flow of the remote flowmeter FI is normal. After the pressure rises to the preset hot washing oil pressure, refer to step 6) for the pipeline pressure relief process and repeat this flushing process 3 times (the number of times is adjustable);

[0040] 8) Continuous hot washing of line A: Open HV3 valve and HV4 valve, confirm that the remote flow meter FI is normal, and continuously flush with hot solvent for 20 minutes (time is adjustable). If the hot solvent flow remains normal, it is judged that the hot washing of each valve in line A is completed;

[0041] 9) Close the HV4 valve, wait for the remote pressure gauge PZT1 pressure to reach the system pressure during normal production, and then close the HV3 valve. At this time, line A is in normal standby after hot washing.

[0042] If line B operates abnormally, the same method from step 1) to step 9) is used to switch from line B to line A.

[0043] Each valve in the present application is preferably configured as an electrically controlled valve, which is centrally regulated by a DCS system.

[0044] Finally, it should be noted that the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by ordinary technicians in this field should be considered as the protection scope of the present invention.

Claims

1. A system for reducing the number of mechanical cleaning times of easily blocked valves, characterized in that: It includes line A and line B laid in a pipeline manner, the left and right ends of the line A are connected to the reactor and the downstream system respectively, the line A is sequentially connected with an HV1 valve, an LV1 control valve, a pressure relief valve equipped with a remote pressure gauge PZT1, and an HV2 valve, and a hot solvent flushing system is connected to the line A between the pressure relief valve equipped with a remote pressure gauge PZT1 and the HV2 valve; One end of the B line is connected to the inlet end of the HV1 valve, and the other end of the B line is connected to the outlet end of the HV2 valve. The B line is sequentially connected with the HV5 valve, the pressure relief valve equipped with the remote pressure gauge PZT2, the LV2 control valve, and the HV6 valve. The A line between the HV1 valve and the LV1 control valve is connected to the No. 1 pipeline with the HV4 valve. The B line between the HV5 valve and the LV2 control valve is connected to the No. 2 pipeline with the HV8 valve. The No. 1 pipeline and the No. 2 pipeline are connected to the solvent recovery tank after being combined; The hot solvent flushing system includes a hot solvent recovery tank, which is connected to pipeline No. 3 with a remote flow meter FI. The hot solvent flushing system is connected to line A through pipeline No.

3. Pipeline No. 3 is also connected to an HV3 valve. The inlet end of the HV3 valve is connected to pipeline No.

4. Pipeline No. 4 is connected to the pressure relief valve equipped with a pressure test PZT2 and line B between the HV6 valve. The pipeline No. 4 is connected to an HV7 valve. A liquid level control valve is provided in the reactor, and the LV1 control valve and the LV2 control valve can be connected in series with the liquid level control valve.

2. A system for reducing the number of mechanical cleaning times of easily blocked valves according to claim 1, characterized in that: The LV1 control valve, LV1 control valve, pressure relief valve, HV1 valve, HV2 valve, HV3 valve, HV4 valve, HV5 valve, HV6 valve, HV7 valve, and HV8 valve are all electronically controlled valves connected by communication, and also include a DCS system connected to the remote pressure gauge PZT1, remote pressure gauge PZT2, remote flowmeter FI and each valve.

3. A process for reducing the number of mechanical cleaning times of easily blocked valves, characterized in that The process method includes: 1) Under normal operating conditions, the HV1 valve and HV2 valve in line A are opened, the HV3 valve and HV4 valve are closed, and the LV1 control valve is connected in series with the liquid level control valve to realize automatic liquid level control; under normal operating conditions, the liquid level in the reactor is controlled at 50±5%, and the opening of the LV1 control valve is 55±3%; the HV5 valve, HV6 valve, HV7 valve, and HV8 valve in line B are closed, and the LV2 valve is opened to serve as a backup switching line; 2) When the opening of the LV1 control valve is opened to more than 58%, the liquid level in the reactor continues to rise above the preset value, and the value of the remote pressure gauge PZT1 drops, the alarm is triggered, the delay is set to 15S, and the line is switched to B; When putting Line B into use, first close the LV2 control valve to 0%, open the HV5 valve and HV6 valve, confirm that the HV5 valve and HV6 valve are open, slowly open the LV2 control valve, and set the opening OP at 0.2% / time, and set the climbing abnormal alarm according to actual needs; 3) Cut out line A: When line B is in normal excess, the liquid level in the reactor drops, and the LV1 control valve is gradually closed. When the OP of the LV1 control valve is consistent with that of the LV2 control valve, the LV2 control valve is connected in series with the liquid level control valve in the reactor. After a delay of 10 seconds, when the liquid level in the reactor is stable, the LV1 control valve is disconnected in series with the liquid level control valve in the reactor, and the LV1 control valve is slowly closed at an opening OP of 0.2% / time, and the abnormal climbing alarm is set according to actual needs until LV1 is closed to 0%; 4) When the LV1 control valve is closed to 0%, the reaction liquid level in the reactor does not rise, and the LV2 control valve opening OP is the same as the LV1 control valve opening OP, it is confirmed that the B line is put into use normally; 5) Isolate line A: close HV1 valve and HV2 valve; 6) Confirm the hot solvent pressure and temperature in the hot solvent recovery tank. If the pressure and temperature of the hot solvent recovery tank reaches the preset required value, perform pressure relief stage 1, open the HV4 valve to 25%, open the LV1 valve, and release the pipeline pressure PZT1 of the pressure relief valve equipped with the remote pressure gauge PZT1 to 30% of the normal pipeline pressure PZT1 pressure; in the pressure relief stage 2, release the pipeline pressure PZT1 solvent pressure of the pressure relief valve equipped with the remote pressure gauge PZT1 to the pressure of the solvent buffer tank, close the HV4 valve, and the pressure relief is completed; 7) Intermittent hot washing of line A: Open the HV3 valve and observe whether the flow of the remote flow meter FI is normal. After the pressure rises to the preset hot washing oil pressure, refer to step 6) for the pipeline pressure relief process and repeat this flushing process 3 times; 8) Continuous hot washing of line A: Open valves HV3 and HV4, confirm that the remote flow meter FI is normal, and continuously flush with hot solvent for 20 minutes. If the hot solvent flow remains normal, it is judged that the hot washing of each valve in line A is completed; 9) Close the HV4 valve, wait for the remote pressure gauge PZT1 pressure to reach the system pressure during normal production, and then close the HV3 valve. At this time, line A is in normal standby after hot washing.

4. A process method for reducing the number of mechanical cleaning times of easily blocked valves according to claim 3, characterized in that: If line B operates abnormally, the same method from step 1) to step 9) is used to switch from line B to line A.

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