Material conveying system and polypropylene catalyst system

Abstract

This invention relates to a material conveying system and a polypropylene catalyst system including the material conveying system. The material conveying system includes a main pipeline for conveying material in fluid form and a detection branch connected to the main pipeline for detecting pressure in the main pipeline; the upstream end of the main pipeline is fluidly connected to a material source and its downstream end is fluidly connected to a material reactor; wherein, the detection branch is provided with a first valve in a normally open state, a pressure gauge connected to the first valve, and an exhaust ring for venting gas from the detection branch; the pressure gauge and the exhaust ring are connected to each other and together define the branch channel for material flow. The material conveying system of this invention has a reduced branch channel volume in the detection branch, thus reducing the amount of material retained in the dead zone, thereby minimizing the impact of dead zone residual material on product quality / performance.

Description

Technical Field

[0001] This utility model relates to the field of catalyst technology, and more specifically to a material conveying system and a polypropylene catalyst system including such a material conveying system. Background Technology

[0002] In the industrial production of polypropylene, catalysts and modifiers are key materials for the polymerization reaction, and the stability of their delivery system and the purity of the materials directly determine the quality of the final polypropylene product. To monitor the pressure status of catalyst / modifier pipelines in real time, pressure gauges are commonly installed at the connection points of the main delivery pipelines to achieve accurate monitoring and early warning of abnormalities in the delivery pressure of materials (such as main catalysts or modifiers), ensuring the stability of the polymerization reaction.

[0003] In existing technologies, according to industry design specifications, a relatively large-diameter (e.g., 2-inch) connecting pipe is typically used on the detection branch equipped with a pressure gauge, along with a root valve of the corresponding diameter (e.g., 2-inch) to connect or disconnect the detection branch from the main delivery pipeline. Under normal operation or material conveying conditions, the root valve is normally open, but can be closed to cut off the material passage when the pressure gauge needs maintenance or replacement.

[0004] However, this traditional connection structure has significant technical drawbacks in practical applications. In particular, due to the large volume of the internal channels of the connecting pipes and root valves, a material stagnation dead zone forms within the area of ​​the connecting pipes and root valves during normal material transport, especially for catalysts in a slurry state. This results in a large amount of material being stored within the internal volume defined by the connecting pipes and root valves. This poses a certain risk in polypropylene production. For example, when switching between different types of catalysts or modifiers, the existing material stored in the aforementioned dead zone is difficult to completely remove in a short time. Fluctuations in downstream pressure can also lead to quality risks. For instance, when the downstream pressure of the main conveying pipeline fluctuates (such as pressure changes within the polymerization reactor), the pressure balance within the dead zone is disrupted. Residual material, under the influence of the pressure difference, gradually "seeps" out of the dead zone and enters the main conveying pipeline, mixing with the new material before being transported to the downstream polymerization reaction system. This can adversely cause the polymerization reaction conditions to deviate from the set parameters, leading to fluctuations in the performance of the final polypropylene product, and even the production of substandard products, seriously affecting production stability and product quality consistency.

[0005] Therefore, there is an urgent need for a new material conveying system that can reduce the volume at the detection branch and thus eliminate the impact of dead zone residue as much as possible. Utility Model Content

[0006] The purpose of this utility model is to solve at least one of the above-mentioned problems and / or other problems existing in the prior art.

[0007] According to one aspect of the present invention, a material conveying system is provided, the material conveying system comprising a main pipeline for conveying material in fluid form and a detection branch connected to the main pipeline for detecting pressure in the main pipeline; the upstream end of the main pipeline is fluidly connected to a material source and its downstream end is fluidly connected to a material reactor; wherein, the detection branch is provided with a first valve in a normally open state, a pressure gauge connected to the first valve, and an exhaust ring for venting gas in the detection branch; the pressure gauge and the exhaust ring are connected to each other and together define the branch channel for material flow.

[0008] In one implementation, the diameter of the main pipeline is equal to the diameter of the first valve.

[0009] In one implementation, the diameter of the main pipeline and the diameter of the first valve are both 0.5 inches.

[0010] In one embodiment, the pressure gauge is in the form of a diaphragm pressure gauge, which includes a first flange and a second flange; the vent ring is disposed between the first flange and the second flange, such that the center holes of the first flange, the second flange and the vent ring are coaxially aligned to form the branch channel.

[0011] In one embodiment, sealing gaskets are provided between the first flange and the exhaust ring, and between the second flange and the exhaust ring.

[0012] In one embodiment, the vent ring has a radially extending vent hole on its inner peripheral wall that defines its central hole, and the vent ring is also provided with a second valve that is fluidly connected to the vent hole for controlling the opening or closing of the vent hole.

[0013] In one implementation, the upstream end of the main pipeline is switched to connect to different material sources according to a predetermined time interval.

[0014] In one embodiment, the material is a catalyst or a modifier.

[0015] In one embodiment, the catalyst or modifier is a catalyst or modifier used for the synthesis of polypropylene.

[0016] According to one aspect of the present invention, a polypropylene catalyst system is provided, the polypropylene catalyst system comprising the material conveying system as described above.

[0017] Compared to conventional solutions known in the prior art, the detection branch in the material conveying system according to this invention eliminates the original large-diameter connecting pipe and root valve, and only installs a root valve with the same diameter as the main pipeline, along with a pressure gauge and an exhaust ring directly connected to the root valve. Because the root valve diameter is smaller and the branch channel is jointly defined by the pressure gauge and the exhaust ring, the channel volume is significantly reduced, resulting in less material stagnating in the dead zone. This minimizes the impact of dead zone residue on product quality / performance. Furthermore, by installing the exhaust ring, gas in the detection branch can be released after the system's initial startup or material change, improving the accuracy of pressure detection on the main pipeline and further ensuring the stability of the material conveying system. Attached Figure Description

[0018] The features and advantages of this utility model will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on this utility model, wherein:

[0019] Figure 1 This is a schematic diagram of a material conveying system according to an embodiment of the present utility model;

[0020] Figure 2 This is a schematic diagram showing the assembly of the two flanges and the vent ring of a diaphragm pressure gauge; and

[0021] Figure 3 This is a schematic diagram of the exhaust ring according to a specific embodiment of the present invention. Detailed Implementation

[0022] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be implemented with any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims unless expressly set forth in the claims.

[0023] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0024] This utility model discloses a material conveying system, which is particularly suitable for conveying and pressure monitoring of fluid materials such as catalysts and modifiers during polypropylene synthesis. By optimizing the connection structure of the detection branch, the volume of the dead zone channel is reduced, thereby reducing the amount of material stuck in the dead zone and improving the stability and safety of material conveying.

[0025] like Figure 1 As shown, the material conveying system according to an embodiment of the present invention may include a main pipeline 1 and a detection branch pipeline 2. The main pipeline 1 is used to convey materials in fluid form (e.g., catalysts in slurry form or modifiers in liquid form), and its upstream end may be fluidly connected to different material sources 8 (e.g., catalyst storage tanks or modifier storage tanks) via, for example, a switching valve assembly (not shown in the figure), while its downstream end is fluidly connected to, for example, a material reactor 9 for polypropylene synthesis, to achieve continuous material conveying from the source to the reaction equipment. See also... Figure 1 The detection branch 2 is connected to the middle position between, for example, the upstream and downstream ends of the main pipeline 1, and is used to detect the material pressure in the main pipeline 1 in real time. The detection branch 2 is equipped with a first valve 3 (in the form of a root valve), a pressure gauge 4, and an exhaust ring 5 for venting gas from the detection branch. Under normal operating conditions of the material conveying system, the first valve 3 is always in a normally open state to ensure fluid connectivity between the detection branch 2 and the main pipeline 1, allowing the pressure gauge 4 to reflect pressure changes in the main pipeline 1 in real time, which helps determine whether the material conveying is stable and unobstructed.

[0026] In this embodiment, the diameter of the main pipeline 1 is preferably equal to the diameter of the first valve 3, for example, both being 0.5 inches. This advantageous design reduces turbulence and pressure loss of fluid materials at the connection between the main pipeline 1 and the detection branch 2, ensuring the accuracy of pressure detection. It is particularly suitable for conveying catalysts or modifiers with high viscosity. At the same time, the smaller diameter of the first valve also reduces the amount of material retained at the first valve.

[0027] See also Figure 1 and Figure 2 Pressure gauge 4 may be in the form of a diaphragm pressure gauge, which includes a first flange 41 and a second flange 42 disposed opposite to each other. See in particular Figure 2The exhaust ring 5 is a disc-shaped component and can be positioned between the first flange 41 and the second flange 42. The center holes (not specifically shown in the figure) of the first flange 41, the second flange 42, and the exhaust ring 5 are coaxially aligned to form a branch channel for material flow (i.e., after entering from the main pipeline 1 through the first valve 3, the material sequentially passes through the center hole of the first flange 41, the center hole of the exhaust ring 5, and the center hole of the second flange 42, finally contacting the diaphragm and driving the pressure gauge 4 to display the pressure value). To ensure the sealing of the branch channel, chemically resistant sealing gaskets 6 are provided between the first flange 41 and the exhaust ring 5, and between the second flange 42 and the exhaust ring 5, to prevent material leakage.

[0028] As can be seen from the above, the detection branch in the material conveying system of this utility model eliminates the large-diameter connecting pipe and large-diameter root valve in the existing design, and only sets up a root valve with the same diameter as the main pipe, as well as a pressure gauge and exhaust ring directly connected to the root valve. Through calculation and comparative analysis, the applicant found that, for the connection structure mentioned in the background art using a 2-inch connecting pipe and a 2-inch root valve, when conveying the main catalyst used in polypropylene synthesis, approximately 1.18 kg of residual material would remain in the dead zone. However, after adopting the improved technical solution according to this utility model, the residual material remaining in the dead zone is significantly reduced to only 0.17 kg. Furthermore, when conveying the modifier used in polypropylene synthesis, approximately 1.07 kg of residual material would remain in the dead zone. However, after adopting the improved technical solution according to this utility model, the residual material remaining in the dead zone is significantly reduced to only 0.12 kg. Therefore, it can be seen that the technical solution of this utility model has a significantly reduced channel volume, resulting in a reduction in the amount of material remaining in the dead zone, thus minimizing the impact of dead zone residue on product quality / performance.

[0029] See also Figure 3 The diagram illustrates the structure of an exhaust ring according to a specific embodiment of the present invention. An exhaust hole 51 extending radially is provided on the inner peripheral wall of the exhaust ring 5 (i.e., the wall surface defining the central hole), and a second valve 52 in fluid communication with the exhaust hole 51 is installed on the outer peripheral wall of the exhaust ring 5. When residual gas is detected in the branch 2 (such as after initial system startup or material replacement), the second valve 52 can be opened to allow the gas to be discharged through the exhaust hole 51 and the second valve 52. Once continuous material flow is observed, the second valve 52 is closed to ensure the branch channel is filled with material, preventing gas interference with pressure detection, thus improving the accuracy of main pipeline pressure detection and ensuring the stability of the material conveying system.

[0030] As mentioned earlier, the upstream end of main pipeline 1 can be switched to connect to different material sources (e.g., depending on the material output rate, such as an interval of 7-8 hours) according to predetermined time intervals. Figure 1 (The connection relationship is shown by dashed lines). For example, in the polypropylene synthesis process, main pipeline 1 can be connected to the catalyst source first, and the catalyst can be delivered to the reactor according to the dosage. After a predetermined time, the switching valve group is activated to switch main pipeline 1 to the modifier source, and the modifier can continue to be delivered, realizing the continuous alternating delivery of multiple materials. Of course, it should be understood that the switching of different material sources here can also be the switching between different storage tanks of the same type of material.

[0031] Since the detection branch 2 of the material conveying system can monitor the pressure in the main pipeline 1 in real time, during the material switching process, the change in the reading of the pressure gauge 4 can be used to determine whether the switching is in place (such as a sudden pressure change indicating that the material source has been switched). At the same time, the exhaust ring 5 can promptly discharge the gas mixed in during the switching process, ensuring the continuity and accuracy of pressure monitoring.

[0032] In this embodiment, the material can specifically be a catalyst or modifier used for synthesizing polypropylene, and the material conveying system described above can be used in the polypropylene catalyst system. In actual operation, the catalyst used for polypropylene synthesis can be conveyed from the storage tank to the material reactor via the main pipeline 1. The first valve 3 is normally open, and the pressure gauge 4 displays the pressure in the main pipeline 1 in real time. When the system is shut down and restarted, the second valve 52 is opened to purge the air in the detection branch 2. After catalyst flows out, the second valve 52 is closed to ensure that the reading of the pressure gauge 4 accurately reflects the catalyst delivery pressure and avoids catalyst metering deviation caused by abnormal pressure.

[0033] According to the material conveying system of this utility model, by improving the design of the detection branch, the amount of material stuck in the dead zone is reduced, thereby minimizing the impact of dead zone residue on product quality / performance. In addition, by setting an exhaust ring, the accuracy of the pressure detection of the main pipeline is improved, ensuring the stability of the material conveying system.

[0034] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of this invention. Other embodiments of this invention will be apparent to those skilled in the art based on the practice of this invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A material conveying system, characterized in that, The material conveying system includes a main pipeline (1) for conveying material in fluid form and a detection branch (2) connected to the main pipeline (1) for detecting the pressure in the main pipeline; the upstream end of the main pipeline is fluidly connected to a material source (8) and the downstream end is fluidly connected to a material reactor (9); wherein, the detection branch (2) is provided with a first valve (3) in a normally open state, a pressure gauge (4) connected to the first valve, and an exhaust ring (5) for venting gas in the detection branch; the pressure gauge (4) and the exhaust ring (5) are connected to each other and together define the branch channel for material flow.

2. The material conveying system according to claim 1, characterized in that, The diameter of the main pipeline (1) is equal to the diameter of the first valve (3).

3. The material conveying system according to claim 2, characterized in that, The diameter of the main pipeline (1) and the diameter of the first valve (3) are both 0.5 inches.

4. The material conveying system according to any one of claims 1 to 3, characterized in that, The pressure gauge (4) is in the form of a diaphragm pressure gauge, which includes a first flange (41) and a second flange (42); the exhaust ring (5) is disposed between the first flange and the second flange, such that the center holes of the first flange, the second flange and the exhaust ring are coaxially aligned to form the branch channel.

5. The material conveying system according to claim 4, characterized in that, A sealing gasket (6) is provided between the first flange (41) and the exhaust ring (5) and between the second flange (42) and the exhaust ring (5).

6. The material conveying system according to claim 4, characterized in that, The vent ring (5) has a radially extending vent hole (51) on its inner peripheral wall that defines its central hole. The vent ring is also provided with a second valve (52) that is fluidly connected to the vent hole and is used to control the opening or closing of the vent hole.

7. The material conveying system according to any one of claims 1 to 3, characterized in that, The upstream end of the main pipeline (1) is switched to connect to different material sources according to a predetermined time interval.

8. The material conveying system according to any one of claims 1 to 3, characterized in that, The material is a catalyst or a modifier.

9. The material conveying system according to claim 8, characterized in that, The catalyst or modifier is a catalyst or modifier used for the synthesis of polypropylene.

10. A polypropylene catalyst system, characterized in that, The polypropylene catalyst system includes a material conveying system according to any one of claims 1 to 9.

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