Reactor catalyst supply system for producing polyethylene

Abstract

The utility model relates to a reactor catalyst supply system for producing polyethylene. The reactor catalyst supply system comprises a catalyst retention tank and two catalyst supply flows connected in parallel at the downstream of the catalyst retention tank, a crossover line is additionally arranged between the third-reaction catalyst supply pipeline and the first-reaction catalyst supply pipeline for parallel connection; through modification, a third metering pump is added in parallel on the basis of an original first metering pump and an original second metering pump, the phenomenon that a reactor must be shut down when the first metering pump or the second metering pump breaks down for a long time is avoided, and through modification of a third-reaction catalyst supply pipeline, the third-reaction catalyst supply pipeline and a first-reaction catalyst supply pipeline are connected in parallel, so that the first-reaction catalyst supply pipeline and the second-reaction catalyst supply pipeline are connected in parallel. Isolation from a secondary reaction catalyst supply pipeline is realized, and the problem that the second reactor and the third reactor are connected in parallel or the first reactor and the third reactor are connected in parallel to realize catalyst feeding is solved; through the technology, the influence of primary reaction or secondary reaction maintenance or catalyst metering pump maintenance on the production load of the device can be avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the supply structure of catalyst in polyethylene process, concretely relates to a reactor catalyst supply system for producing polyethylene, and carries out the optimized supply for polyethylene process, solves the problem that parallel catalyst feeding cannot be realized because of shutdown, belongs to the pipeline reconstruction technical field of chemical production process. BACKGROUND

[0002] The polyethylene Hostalen process before optimization structure has three reactors, can produce in series or parallel mode, and the parallel mode is designed as the first reactor and the second reactor in the process package, therefore two catalyst metering pumps are designed downstream of the catalyst residence tank, the first metering pump and the second metering pump, the two metering pump outlets are connected with the first and second catalyst metering pipelines respectively, the first catalyst metering pipeline terminal is connected with the first reverse catalyst supply line, and the second reverse catalyst supply line and the third reverse catalyst supply line are connected in parallel on the catalyst second metering pipeline.

[0003] When the first metering pump or the second metering pump appears long fault, the reactor has no catalyst feeding for a period of time, and the phenomenon that the reactor must be shut down is caused.

[0004] When the first reverse reactor or the second reverse reactor needs regular maintenance, and the second reverse catalyst supply line and the third reverse catalyst supply line are connected in parallel on the catalyst second metering pipeline, the parallel connection of the second reactor and the third reactor or the parallel connection of the first reactor and the third reactor cannot realize catalyst feeding. UTILITY MODEL CONTENT

[0005] In view of the above-mentioned technical problem that the reactor must be shut down when the metering pump of the polyethylene Hostalen process pipeline form fails, the utility model aims at providing a reactor catalyst supply system for producing polyethylene, according to the pipeline reconstruction of the design process flow, the influence of the device production load caused by the maintenance of the reactor (first reverse or second reverse) or the maintenance of the catalyst metering pump can be avoided.

[0006] In order to achieve the above object, the utility model adopts the technical scheme of: a reactor catalyst supply system for producing polyethylene, comprising: a catalyst residence tank and two catalyst supply processes connected downstream thereof; wherein one catalyst supply process is connected to a first reactor, and the other catalyst supply process is connected to a second reactor and a third reactor in parallel through a branch pipeline; the catalyst supply process connected to the first reactor is connected to the first reactor through a first catalyst supply pipeline; the other catalyst supply process is connected to the second reactor through a second catalyst supply pipeline and connected to the third reactor through a third catalyst supply pipeline; a cross line is added between the third catalyst supply pipeline and the first catalyst supply pipeline to realize parallel connection; and the third catalyst supply pipeline and the second catalyst supply pipeline are isolated.

[0007] The above modification of the third catalyst supply pipeline solves the problem of catalyst feeding of the second reactor and the third reactor in parallel or the first reactor and the third reactor in parallel.

[0008] Further, respective control valves are arranged on the first catalyst supply pipeline, the second catalyst supply pipeline and the third catalyst supply pipeline, and a corresponding control valve is arranged on the cross line between the third catalyst supply pipeline and the first catalyst supply pipeline; when any reactor needs to be repaired, the different processes are switched to open or close the control valves.

[0009] Further, the two catalyst supply processes are a first supply process and a second supply process; the same end of the first supply process and the second supply process is connected to one side of the catalyst residence tank.

[0010] Further, the first supply process comprises a first metering pump, a first catalyst metering pipeline, a first flow meter and the first catalyst supply pipeline; one end of the first metering pump is connected to the catalyst residence tank, and the other end is connected to the first catalyst metering pipeline; the inlet and outlet of the first metering pump are respectively provided with one-way valves; the first catalyst metering pipeline is provided with the first flow meter and controlled by a valve; and the first catalyst metering pipeline is connected to the first catalyst supply pipeline.

[0011] Further, the second supply process comprises a second metering pump, a second catalyst metering pipeline, a second flow meter and the second catalyst supply pipeline and the third catalyst supply pipeline; one end of the second metering pump is connected to the catalyst residence tank, and the other end is connected to the second catalyst metering pipeline; the inlet and outlet of the second metering pump are respectively provided with one-way valves; the second catalyst metering pipeline is provided with the second flow meter and controlled by a valve; and the second catalyst supply pipeline and the third catalyst supply pipeline are connected to the second catalyst metering pipeline in parallel.

[0012] Further, the first catalyst metering pipeline and the second catalyst metering pipeline are connected through a pipeline, and a control valve is arranged on the pipeline.

[0013] Further, the first metering pump and the second metering pump are both in the form of reciprocating diaphragm pumps, which are used as the delivery equipment for pressurizing and adjusting the flow of the catalyst.

[0014] Further, the first catalyst metering pipeline and the second catalyst metering pipeline are both delivery pipelines for measuring the flow of the catalyst, which are used for measuring the mass flow of the catalyst.

[0015] Further, in the above scheme, in order to avoid the phenomenon that the reactor must be stopped when the first metering pump or the second metering pump fails for a long time, a third metering pump is added in parallel between the first metering pump and the second metering pump, the inlet and outlet of the third metering pump are connected to the upstream and downstream of the first metering pump and the second metering pump through pipelines, and the pipelines connecting the third metering pump are provided with corresponding inlet valves and outlet valves; when the first metering pump and the second metering pump fail, the reactor does not need to be stopped, and the catalyst can be supplied to the downstream reactors by closing the inlet and outlet gates of the first metering pump and the second metering pump and opening the corresponding control valves of the third metering pump.

[0016] The catalyst supply system adopting the scheme has the beneficial effects that: by means of the reform, a third metering pump is added in parallel on the basis of the original first metering pump and the second metering pump, so that the phenomenon that the reactor must be stopped when the first metering pump or the second metering pump fails for a long time is avoided, and the three-reaction catalyst supply pipeline is also reformed, the three-reaction catalyst supply pipeline is connected in parallel with the one-reaction catalyst supply pipeline, and is isolated from the two-reaction catalyst supply pipeline, so that the problem of feeding the catalyst when the second reactor and the third reactor are connected in parallel or the first reactor and the third reactor are connected in parallel is solved; by means of the technology, the influence of the repair of the one-reaction or the two-reaction or the repair of the catalyst metering pump on the production load of the device can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The figure is a structural diagram of the utility model.

[0018] In the figure, 1 is a catalyst residence tank, 2 is a first reactor, 3 is a second reactor, 4 is a third reactor, 5 is a one-reaction catalyst supply pipeline, 6 is a two-reaction catalyst supply pipeline, 7 is a three-reaction catalyst supply pipeline, 8 is a cross line, 9 is a first metering pump, 10 is a first catalyst metering pipeline, 11 is a first flowmeter, 12 is a second metering pump, 13 is a second catalyst metering pipeline, 14 is a second flowmeter, and 15 is a third metering pump. DETAILED DESCRIPTION

[0019] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0020] like Figure 1 The catalyst supply system for a reactor used in the production of polyethylene, as shown, includes: a catalyst residence tank 1 and two catalyst supply processes connected in parallel downstream; one catalyst supply process is connected to a first reactor 2, and the other catalyst supply process is connected in parallel to a second reactor 3 and a third reactor 4 via branch lines; the catalyst supply process connected to the first reactor 2 is connected to the first reactor 2 via a first-stage catalyst supply line 5; the other catalyst supply process is connected to the second reactor 3 via a second-stage catalyst supply line 6, and simultaneously connected to the third reactor 4 via a third-stage catalyst supply line 7; a crossover line 8 is added between the third-stage catalyst supply line 7 and the first-stage catalyst supply line 5 for parallel connection; this achieves isolation between the third-stage catalyst supply line 7 and the second-stage catalyst supply line 6.

[0021] Each of the primary catalyst supply line 5, the secondary catalyst supply line 6, and the tertiary catalyst supply line 7 is equipped with its own control valve. At the same time, a corresponding control valve is installed on the cross line 8 between the tertiary catalyst supply line 7 and the primary catalyst supply line 5. When any reactor needs maintenance, the different processes are switched to open or close the control valves.

[0022] The two catalyst supply processes are the first supply process and the second supply process, respectively; the same end of the first supply process and the second supply process are both connected to one side of the catalyst residence tank 1.

[0023] The first supply process includes: a first metering pump 9, a first catalyst metering pipeline 10, a first flow meter 11, and a first reaction catalyst supply pipeline 5; the first metering pump 9 is connected to the catalyst residence tank 1 at one end of the pipeline and to the first catalyst metering pipeline 10 at the other end. One-way valves are respectively installed at the inlet and outlet of the first metering pump 9. The first catalyst metering pipeline 10 is equipped with a first flow meter 11 and is controlled by a valve. The first catalyst metering pipeline 10 is connected to the first reaction catalyst supply pipeline 5 at the end.

[0024] The second supply process comprises a second metering pump 12, a second catalyst metering pipeline 13, a second flow meter 14 and a two-way catalyst supply pipeline 6 and a three-way catalyst supply pipeline 7; the second metering pump 12 is connected to the catalyst residence tank 1 through a pipeline at one end and connected to the second catalyst metering pipeline 13 at the other end, the inlet and outlet of the second metering pump 12 are respectively provided with a one-way valve, the second catalyst metering pipeline 13 is provided with the second flow meter 14 and controlled through a valve, and the two-way catalyst supply pipeline 6 and the three-way catalyst supply pipeline 7 are connected in parallel to the second catalyst metering pipeline 13.

[0025] The first catalyst metering pipeline 10 and the second catalyst metering pipeline 13 are connected through a pipeline, and a control valve is arranged on the pipeline.

[0026] In the above scheme, in order to avoid the phenomenon that the reactor must be shut down when the first metering pump 9 or the second metering pump 12 fails for a long time, a third metering pump 15 is arranged in parallel between the first metering pump 9 and the second metering pump 12, the inlet and outlet of the third metering pump 15 are respectively connected to the upstream and downstream of the first metering pump 9 and the second metering pump 12 through pipelines, and the pipelines connected to the third metering pump 15 are respectively provided with corresponding inlet valves and outlet valves; when the first metering pump 9 and the second metering pump 12 fail, the reactor does not need to be shut down, the corresponding control valves of the third metering pump 15 are opened by closing the inlet and outlet gates of the first metering pump 9 and the second metering pump 12, so that the catalyst is supplied to the downstream reactors.

[0027] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0028] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0029] In the utility model, unless another definite provision and limitation, the term "mount", "link", "connect", "fix" and so on term should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated; can be mechanical connection, also can be electrical connection; can be direct connection, also can pass through intermediate medium indirectly connect, can be two element inside's intercommunication or two element's mutual action relation, unless another definite limitation. For the ordinary skill in the art, can understand the concrete meaning of above-mentioned term in the utility model according to specific circumstances.

[0030] In the utility model, unless another definite provision and limitation, first feature is "on" or "under" second feature can be that first and second features directly contact, or first and second features indirectly contact by intermediate medium. Moreover, first feature is "on", "above" and "on" second feature can be that first feature is directly above or obliquely above second feature, or just indicates that the horizontal height of first feature is higher than that of second feature. First feature is "under", "below" and "under" second feature can be that first feature is directly below or obliquely below second feature, or just indicates that the horizontal height of first feature is less than that of second feature.

[0031] It should be noted that when an element is referred to as "fixed to" or "set to" another element, it can be directly on another element or there can be a middle element. When an element is referred to as "connected to" another element, it can be directly connected to another element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

Claims

1. A reactor catalyst supply system for producing polyethylene, characterized by, The application relates to a catalyst residence tank and two catalyst supply processes connected downstream of the catalyst residence tank; wherein one catalyst supply process is connected to a first reactor, and the other catalyst supply process is connected to a second reactor and a third reactor in parallel through branch pipelines; the catalyst supply process connected to the first reactor is connected to the first reactor through a first catalyst supply pipeline; the other catalyst supply process is connected to the second reactor through a second catalyst supply pipeline and connected to the third reactor through a third catalyst supply pipeline; a cross line is added in parallel between the third catalyst supply pipeline and the first catalyst supply pipeline; the two catalyst supply processes are a first supply process and a second supply process; the same end of the first supply process and the second supply process is connected to one side of the catalyst residence tank; the first supply process comprises a first metering pump, a first catalyst metering pipeline, a first flow meter and the first catalyst supply pipeline; one end of the first metering pump is connected to the catalyst residence tank, and the other end is connected to the first catalyst metering pipeline; the inlet and outlet of the first metering pump are respectively provided with one-way valves; the first catalyst metering pipeline is provided with the first flow meter and controlled through a valve; and the first catalyst metering pipeline is connected to the first catalyst supply pipeline; the second supply process comprises a second metering pump, a second catalyst metering pipeline, a second flow meter and the second catalyst supply pipeline and the third catalyst supply pipeline; one end of the second metering pump is connected to the catalyst residence tank, and the other end is connected to the second catalyst metering pipeline; the inlet and outlet of the second metering pump are respectively provided with one-way valves; the second catalyst metering pipeline is provided with the second flow meter and controlled through a valve; the second catalyst supply pipeline and the third catalyst supply pipeline are connected in parallel to the second catalyst metering pipeline; the first catalyst metering pipeline and the second catalyst metering pipeline are connected through a pipeline; and a control valve is arranged on the pipeline. A third metering pump is arranged in parallel between the first metering pump and the second metering pump; the inlet and outlet of the third metering pump are respectively connected to the upstream and downstream of the first metering pump and the second metering pump through pipelines; and the pipelines connected to the third metering pump are respectively provided with corresponding inlet valves and outlet valves.

2. A reactor catalyst supply system for the production of polyethylene according to claim 1, characterized in that: ​

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