A method for resolving pre-polymerization reactor discharge line plugging

Abstract

The application provides a method for solving the blockage of a pre-polymerization reactor discharge line, comprising: isolating a pre-polymerization reactor from a first loop reactor; discharging first material in the pre-polymerization reactor; filling the pre-polymerization reactor with liquid phase propylene; discharging second material in the pre-polymerization reactor; and stopping the isolation of the pre-polymerization reactor from the first loop reactor. The application can conveniently solve the problem of the blockage of the pre-polymerization reactor discharge line, effectively reduce the material cost, and ensure the long-period normal operation of the pre-polymerization reactor.

Description

Technical Field

[0001] This invention relates to the field of polypropylene process technology, and in particular to a method for solving the blockage of the discharge line of a prepolymer reactor. Background Technology

[0002] In the dual-loop polypropylene process, the prepolymerization reactor and the first loop reactor are connected by the prepolymerization reactor discharge line. In actual production, the prepolymerization reactor discharge line is affected by the smoothness of the pipeline, the flange connection gasket, and the smoothness of the discharge plunger valve channel, which causes the pressure in the prepolymerization reactor to rise. This leads to poor discharge from the prepolymerization reactor, or even failure to discharge, requiring large-scale shutdown of the equipment and spending a lot of time repairing the prepolymerization reactor discharge line. This not only increases material costs but also affects the long-term operation of the prepolymerization reactor. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method for solving the blockage of the discharge line of a prepolymerization reactor. By introducing liquid propylene, a pressure difference is generated between the inside and outside of the prepolymerization reactor. The pressure difference is used to discharge the deposits in the discharge line of the prepolymerization reactor. This method can conveniently solve the problem of blockage of the discharge line of the prepolymerization reactor without large-scale equipment shutdown, effectively reduce material costs, and ensure that the prepolymerization reactor can operate normally for a long period of time.

[0004] In a first aspect, embodiments of the present invention provide a method for solving the blockage of the discharge line of a prepolymerization reactor, characterized in that it includes:

[0005] Step 1: Isolate the prepolymerization reactor from the first loop reactor;

[0006] Preferably, the feeding of the three agents and propylene into the prepolymerization reactor is stopped;

[0007] Step 2: Discharge the first material from the prepolymerization reactor;

[0008] Preferably, the first material in the prepolymerization reactor is discharged to a low-pressure flare system;

[0009] Step 3: Introduce liquid propylene into the prepolymerization reactor to bring the internal pressure of the prepolymerization reactor to the first operating pressure, and then discharge the second material from the prepolymerization reactor;

[0010] The second material includes the liquid propylene and the deposits in the discharge line of the prepolymerization reactor;

[0011] Preferably, the operation of repeatedly filling the prepolymerization reactor with the liquid propylene to bring the interior of the prepolymerization reactor to a first operating pressure and then discharging the second material from the prepolymerization reactor is performed.

[0012] Preferably, the second material in the prepolymerization reactor is discharged to a low-pressure flare system;

[0013] Step 4: Stop isolating the prepolymerization reactor from the first loop reactor;

[0014] Preferably, after the prepolymerization reactor is isolated from the first loop reactor, the manual valve of the discharge plunger valve is opened, and when the internal pressure of the prepolymerization reactor reaches the second operating pressure, the manual valve of the discharge plunger valve is closed.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a method for solving the blockage of the discharge line of a prepolymerization reactor, provided by an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram illustrating the working principle of a method for solving the blockage of the discharge line of a prepolymerization reactor, provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The present invention provides a method for solving the blockage of the discharge line of a prepolymerization reactor, which can remove the deposits in the discharge line of the prepolymerization reactor without stopping the operation, thus solving the problem of blockage of the discharge line of the prepolymerization reactor.

[0022] To facilitate understanding of this embodiment, in conjunction with Figure 1 This invention provides a detailed description of a method for solving the blockage of the discharge line of a prepolymer reactor, as disclosed in an embodiment of the invention.

[0023] Example 1:

[0024] The method for solving the blockage of the discharge line of a prepolymerization reactor disclosed in this embodiment of the invention comprises the following steps:

[0025] Step 1: Isolate the prepolymerization reactor from the first loop reactor;

[0026] Specifically, the internal operator activates the interlocking system, and the external operator closes the manual valve of the discharge plunger valve to isolate the prepolymerization reactor from the first loop reactor. The interlocking system is used to control, but is not limited to, the prepolymerization reactor, the first loop reactor, the discharge plunger valve, the regulating valve, and the discharge valve after startup. The manual valve of the discharge plunger valve is installed at one end of the discharge line of the prepolymerization reactor, located inside the first loop reactor.

[0027] Preferably, the feeding of the three agents and propylene into the prepolymerization reactor is stopped;

[0028] Step 2: Discharge the first material from the prepolymerization reactor;

[0029] Specifically, the operator opens the manual valve of the discharge valve at the bottom of the prepolymerization reactor to discharge the first material in the prepolymerization reactor; the first material is the material remaining in the prepolymerization reactor, including polypropylene slurry and three agents;

[0030] Preferably, the first material in the prepolymerization reactor is discharged to a low-pressure flare system;

[0031] Step 3: Introduce liquid propylene into the prepolymerization reactor to bring the internal pressure of the prepolymerization reactor to the first operating pressure, and then discharge the second material from the prepolymerization reactor.

[0032] Specifically, the operator fills the prepolymerization reactor with liquid propylene through the regulating valve of the propylene feed until the internal pressure of the prepolymerization reactor reaches the first operating pressure. Once the internal pressure of the prepolymerization reactor reaches the first operating pressure, the operator opens the manual valve of the discharge valve at the bottom of the prepolymerization reactor. At this time, a pressure difference is generated between the inside and outside of the prepolymerization reactor, which allows the second material to be discharged through the discharge valve. The second material includes liquid propylene and the deposits in the discharge line of the prepolymerization reactor.

[0033] Preferably, the operation of repeatedly filling the prepolymerization reactor with liquid propylene to bring the interior of the prepolymerization reactor to a first operating pressure and discharging the second material from the prepolymerization reactor is performed; exemplarily, the operation is repeated 2 to 3 times.

[0034] Preferably, the second material in the prepolymerization reactor is discharged to a low-pressure flare system;

[0035] Step 4: Stop isolating the prepolymerization reactor from the first loop reactor;

[0036] Specifically, the internal operator resets the interlock system, at which point the discharge valve at the bottom of the prepolymer reactor closes, stopping the isolation between the prepolymer reactor and the first loop reactor, and completing the cleaning of the prepolymer reactor discharge line;

[0037] Preferably, after the prepolymerization reactor is isolated from the first loop reactor, the manual valve of the discharge plunger valve is opened, and when the internal pressure of the prepolymerization reactor reaches the second operating pressure, the manual valve of the discharge plunger valve is closed.

[0038] Specifically, after the prepolymerization reactor is isolated from the first loop reactor, the operator opens the manual valve of the discharge plunger valve. When the internal pressure of the prepolymerization reactor reaches the second operating pressure, the manual valve of the discharge plunger valve is closed. The opening and closing operation of the manual valve of the discharge plunger valve can clean the deposits inside the valve body channel of the discharge plunger valve.

[0039] Example 2:

[0040] To enable those skilled in the art to better and more clearly understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments. The specific steps are as follows:

[0041] Taking a 100,000-ton / year polypropylene plant as an example, combined with Figure 2The internal operator activates the interlocking system IS202, and the external operator closes the hand valve HV2203A of the discharge plunger valve to isolate the prepolymerization reactor R200 from the first loop reactor R201. At the same time, the feeding of the three agents and propylene into the prepolymerization reactor R200 is stopped. At this time, the pressure inside the prepolymerization reactor R200 is about 3.8 MPa.

[0042] The operator opened the discharge valve HV2203B at the bottom of the prepolymerization reactor R200 to discharge the remaining polypropylene slurry and three agents in the prepolymerization reactor R200 to the low-pressure flare system. At this time, the pressure in the prepolymerization reactor R200 was 0 MPa.

[0043] The operator fills the prepolymer reactor R200 with liquid propylene through the cross-line of the propylene feed regulating valves FV2004 and FV2201 until the prepolymer reactor R200 reaches the operating pressure of 4.0 MPa. At this time, the liquid propylene and the attached substances in the discharge line of the prepolymer reactor are discharged to the low-pressure flare system.

[0044] The operation of filling the prepolymer reactor R200 with liquid propylene and discharging the liquid propylene from the prepolymer reactor R200 was repeated three times.

[0045] The internal operator resets the interlock system IS202. At this time, the discharge valve HV2203B at the bottom of the prepolymerization reactor R200 is closed, and the external operator closes the manual valve of the discharge plunger valve HV2203A. After the pressure in the prepolymerization reactor R200 rises to 4.2MPa, the manual valve of the discharge plunger valve HV2203A is quickly opened. At this time, the pressure in the prepolymerization reactor R200 is about 3.5MPa, which can carry out normal production operations.

[0046] Specifically, by cleaning the discharge line of the prepolymer reactor and removing the deposits inside the discharge plunger valve body, propylene loss can be reduced by 10 tons, saving approximately 56,800 yuan in propylene costs; nitrogen loss can be reduced by 40,000 standard cubic meters, saving approximately 40,000 yuan in nitrogen costs; based on a polypropylene benefit of 450 yuan / ton, a loss of 540,000 yuan can be avoided in 96 hours, resulting in a total cost saving of 636,800 yuan.

[0047] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method of resolving pre-polymerization reactor discharge line plugging, characterized by, The method comprises: Step 1: isolating the prepolymerization reactor from the first loop reactor; Step 2: discharging a first material in the prepolymerization reactor; Step 3: filling the prepolymerization reactor with liquid phase propylene, so that the interior of the prepolymerization reactor reaches a first operating pressure, and discharging a second material in the prepolymerization reactor; wherein the second material comprises the liquid phase propylene and attachments in the discharge line of the prepolymerization reactor; Step 4: stopping the isolation of the prepolymerization reactor from the first loop reactor.

2. A method of resolving pre-polymer reactor discharge line plugging as claimed in claim 1, wherein, The isolation of the prepolymerization reactor from the first loop reactor in the step 1 further comprises: stopping the transmission of the third agent feed and the propylene feed to the prepolymerization reactor.

3. The method of resolving pre-polymer reactor discharge line plugging as claimed in claim 1, wherein, The discharging of the first material in the prepolymerization reactor in the step 2 comprises: discharging the first material in the prepolymerization reactor to a low-pressure flare system.

4. The method of resolving pre-polymer reactor discharge line plugging as claimed in claim 1, wherein, The filling of the prepolymerization reactor with liquid phase propylene, so that the interior of the prepolymerization reactor reaches a first operating pressure, and discharging a second material in the prepolymerization reactor in the step 3 further comprises: repeating the operation of filling the prepolymerization reactor with the liquid phase propylene, so that the interior of the prepolymerization reactor reaches a first operating pressure, and discharging a second material in the prepolymerization reactor.

5. The method of resolving pre-polymer reactor discharge line plugging as claimed in claim 1, wherein, The discharging of the second material in the prepolymerization reactor in the step 3 comprises: discharging the second material in the prepolymerization reactor to a low-pressure flare system.

6. The method of resolving pre-polymer reactor discharge line plugging as claimed in claim 1, wherein, The stopping of the isolation of the prepolymerization reactor from the first loop reactor in the step 4 further comprises: opening a hand valve of a discharge plunger valve, and closing the hand valve of the discharge plunger valve when the interior of the prepolymerization reactor reaches a second operating pressure.

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