Para-aramid polymerization solvent system conveying device

Abstract

The utility model relates to the technical field of para-aramid production, in particular to a para-aramid polymerization solvent system conveying device. And the para-aramid polymerization solvent system is conveyed to the polymerizer through the conveying assembly. The conveying assembly comprises a pump arranged at the front end of the conveying assembly and used for providing power for conveyed materials; the conveying pipeline is connected with an outlet of the pump and an inlet of the polymerizer, the conveying pipeline is a double-layer pipeline, the inner layer of the conveying pipeline is used for conveying materials, and the interlayer of the conveying pipeline is communicated with an external refrigerant source or a heating medium source and used for refrigerating or heating the materials in the conveying pipeline. When the conveying pipeline is blocked, a heating medium is input into the interlayer of the conveying pipeline to heat materials in the conveying pipeline, the materials are dissolved or washed clean through flowing of the materials in the pipeline, and the pipeline is dredged under the condition that the pipeline is not disassembled.

Description

Technical Field

[0001] This utility model relates to the field of para-aramid production technology, and in particular to a para-aramid polymerization solvent system conveying device. Background Technology

[0002] Para-aramid fibers possess excellent mechanical properties, high temperature resistance, and chemical corrosion resistance, making them widely used in many high-end fields. Their preparation technology has always been one of the research hotspots in the field of materials science.

[0003] Low-temperature solution polycondensation is a commonly used method in the polymerization of para-aramid fibers. This method uses TPC (terephthaloyl chloride) and PPD (p-phenylenediamine) as raw materials, and polymerizes them at low temperatures in an amide-type aprotic polar solvent system such as N-methylpyrrolidone (NMP) to produce PPTA. Because the monomers TPC and PPD are highly reactive, and the product PPTA is difficult to dissolve in common solvents, an amide-type aprotic polar solvent such as NMP must be used, and a co-solvent (such as calcium chloride or lithium chloride) must be added. The cations in the co-solvent can complex with the carbonyl group of NMP, and the anions can combine with the hydrogen atoms on the amide bonds of the polymer, thereby increasing the solubility of PPTA. Currently, the commonly used solvent system is NMP and calcium chloride. Within a certain range, the higher the amount of calcium chloride used, the higher the molecular weight of the PPTA obtained from the polymerization.

[0004] In actual production, to improve the dissolution rate of calcium chloride in NMP, NMP is usually heated first, then calcium chloride is added and stirred to dissolve, followed by the addition of PPD to form a PPD solvent system. To ensure the smooth progress of the polymerization reaction, two key conditions must be met: first, the temperature of the PPD solvent system must be precisely controlled between 5 and 10 degrees Celsius; second, the feeding method for TPC and PPD should be continuous, and the feeding ratio between the two must be accurate. This is because, theoretically, in polycondensation reactions, only by maintaining equal amounts of the two monomers can the molecular weight of the polymer product be increased; even extremely small deviations in the ratio will significantly affect the molecular weight of the polymer.

[0005] However, temperature control in actual production presents a significant challenge. To maintain the PPD solvent system temperature between 5 and 10 degrees Celsius, refrigeration measures are often required in the delivery pipeline. However, during refrigeration, calcium chloride in the PPD solvent system easily precipitates and condenses on the inner wall of the pipeline. This phenomenon not only severely affects the accuracy of flow control, making it difficult for the polymerization reaction to proceed according to the expected feed ratio, but in more severe cases, it can cause complete pipeline blockage, leading to the shutdown of the entire production equipment, resulting in production interruptions, a significant reduction in efficiency, and a sharp increase in costs, severely restricting the industrial production efficiency and quality stability of para-aramid. Therefore, there is an urgent need to develop a novel para-aramid polymerization solvent system delivery device to effectively solve the above problems. Utility Model Content

[0006] The purpose of this invention is to provide a delivery device for a para-aramid polymerization solvent system to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A para-aramid polymerization solvent system conveying device, characterized in that it includes: a conveying assembly for conveying the para-aramid polymerization solvent system to the polymerizer;

[0009] The conveying assembly includes:

[0010] A pump, located at the front end of the conveying assembly, is used to provide power for the conveyed materials;

[0011] The conveying pipeline connects the outlet of the pump and the inlet of the polymerizer. The conveying pipeline is a double-layered pipeline, with the inner layer used for conveying materials and the interlayer connected to an external refrigerant or heat source for cooling or heating the materials inside the pipeline.

[0012] A flow meter is installed on a conveying pipeline to detect the flow rate of materials within the pipeline.

[0013] A thermometer, installed on a conveying pipeline, is used to detect the temperature of the material inside the pipeline.

[0014] As a further embodiment of the present invention, the inlet end of the refrigerant source or heat source of the conveying pipe jacket is located at the end of the material direction, and the outlet end of the refrigerant source or heat source is located at the beginning of the material direction.

[0015] As a further embodiment of this utility model, a refrigerant inlet valve and a heat medium inlet valve are arranged in parallel at the inlet end of the refrigerant source or heat medium source of the conveying pipeline, and a refrigerant outlet valve and a heat medium outlet valve are arranged in parallel at the outlet end of the refrigerant source or heat medium source of the conveying pipeline.

[0016] As a further embodiment of this utility model, it also includes a first valve, a second valve, and a stirring vessel. The stirring vessel is used to prepare and store the para-aramid polymerization solvent system, and its outlet is connected to the inlet of the pump. The first valve is set on the connecting pipe between the output end of the conveying component and the inlet of the polymerizer, and the second valve is set on the connecting pipe between the output end of the conveying component and the stirring vessel.

[0017] As a further embodiment of this utility model, there are two sets of conveying components, which are installed in parallel. The input end of each conveying component is connected to the outlet of the mixing tank, and the output end of each conveying component is connected to the polymerizer and the mixing tank respectively. Corresponding valves are provided to control the flow direction of the material at the output end.

[0018] As a further embodiment of this utility model, it also includes a controller and a frequency converter. The flow meter is electrically connected to the input terminal of the controller, the output terminal of the controller is electrically connected to the signal input terminal of the frequency converter, and the output terminal of the frequency converter is electrically connected to the motor of the pump.

[0019] As a further embodiment of this utility model, the thermometer is electrically connected to the input terminal of the controller.

[0020] The advantages of this utility model are:

[0021] During normal operation, refrigerant is introduced into the jacket of the conveying pipeline to cool the material inside the pipeline and make it meet the polymerization conditions.

[0022] When a blockage occurs in the conveying pipeline, a heating medium is introduced into the interlayer of the pipeline to heat the material inside. The flow of the material inside the pipeline dissolves or flushes it out, thus clearing the blockage without disassembling the pipeline.

[0023] This application also provides an implementation method in which two sets of conveying components are installed in parallel and work alternately. That is, when one conveying component is blocked, the other conveying component is switched to work. A heat medium is introduced into the blocked conveying component to heat the material in the conveying pipe. The flow of the material in the pipe is used to dissolve or flush it clean, and finally the machine can be operated without stopping.

[0024] Other features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a para-aramid polymerization solvent system conveying device according to the present invention;

[0026] Figure 2This is a schematic diagram of the operation of Example 2;

[0027] Figure 3 This is a schematic diagram of the operation of Example 3;

[0028] Figure 4 It is an electrical control function diagram;

[0029] List of reference numerals: 1. Mixing vessel; 2. Conveying assembly; 3. First valve; 4. Second valve; 5. Third valve; 6. Fourth valve; 7. Controller; 8. Frequency converter; 10. Aggregator.

[0030] Pump 201, conveying pipeline 202, flow meter 203, refrigerant outlet valve 204, heat medium outlet valve 205, refrigerant inlet valve 206, heat medium inlet valve 207, thermometer 208. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1

[0032] like Figure 1 As shown, a para-aramid polymerization solvent system conveying device is characterized by comprising: a conveying component 2, which is used to convey the para-aramid polymerization solvent system to the polymerizer 10;

[0033] The conveying assembly 2 includes: a pump 201, located at the front end of the conveying assembly 2, for providing power to the conveyed material; a conveying pipe 202, which connects the outlet of the pump 201 and the inlet of the aggregator 10, the conveying pipe 202 being a double-layer pipe, the inner layer of which is used to convey the material, and the interlayer of which is connected to an external refrigerant source or heat source for cooling or heating the material in the pipe; a flow meter 203, installed on the conveying pipe 202, for detecting the flow rate of the material in the pipe; and a thermometer 208, installed on the conveying pipe 202, for detecting the temperature of the material in the pipe.

[0034] In this embodiment, the prepared para-aramid polymerization solvent system is pumped into the conveying pipe 202 via pump 201. Since NMP needs to be heated to increase the dissolution rate of calcium chloride during the preparation of the para-aramid polymerization solvent system, the resulting dissolved and mixed material has a certain temperature, which does not meet the requirements for subsequent polymerization. Therefore, the material needs to be cooled. Thus, the conveying pipe 202 is configured as a double-layer pipe. The inner layer of the conveying pipe is used to convey the material, and the outer layer is used to convey the temperature-regulating medium. In normal operation, the outer layer of the conveying pipe is connected to an external refrigerant source. The refrigerant flows through the outer layer to cool the material in the inner layer of the conveying pipe. Thermometer 208 is electrically connected to the input terminal of controller 7 and is used to detect whether the temperature of the material in the inner layer of the conveying pipe meets the polymerization requirements.

[0035] When excessive calcium chloride precipitates from the inner layer of the conveying pipe and the pipe needs to be cleared, disconnect the connection between the conveying pipe 202 and the polymerizer, stop the input of refrigerant into the pipe jacket, and instead input high-temperature heat medium. Utilize the flow of material in the pipe to dissolve or flush it clean, thus clearing the pipe without disassembling it.

[0036] In a preferred embodiment of this invention, the inlet end of the refrigerant or heat source in the interlayer of the conveying pipe 202 is located at the end in the material direction, and the outlet end of the refrigerant or heat source is located at the beginning in the material direction. Reversing the flow direction of the temperature-regulating medium from the material flow direction helps to precisely control the temperature of the material inside the conveying pipe 202.

[0037] In a preferred embodiment of this invention, a refrigerant inlet valve 206 and a heat medium inlet valve 207 are provided in parallel at the inlet end of the refrigerant source or heat medium source of the conveying pipeline 202, and a refrigerant outlet valve 204 and a heat medium outlet valve 205 are provided in parallel at the outlet end of the refrigerant source or heat medium source of the conveying pipeline 202. Example 2

[0038] In addition to all the contents of the previous embodiment, this embodiment also includes a first valve 3, a second valve 4, and a stirred tank 1. The stirred tank 1 is used to prepare and store the para-aramid polymerization solvent system, and its outlet is connected to the inlet of the pump 201. The first valve 3 is set on the connecting pipe between the output end of the conveying component 2 and the inlet of the polymerizer 10, and the second valve 4 is set on the connecting pipe between the output end of the conveying component 2 and the stirred tank 1.

[0039] In Embodiment 1, heating the conveying pipe 202 with a heat medium achieves the effect of cleaning the pipe. However, the material inside the pipe cannot be used for polymerization at this time and needs to be recycled through a container. To address this issue, this embodiment sets up a return pipe between the output end of the conveying component 2 and the mixing vessel 1, and sets up a first valve 3 and a second valve 4 to control the flow direction of the material. Specifically, during normal operation, the first valve 3 is open and the second valve 4 is closed, allowing the material to enter the polymerizer 10. When pipe cleaning is required, the first valve 3 is closed and the second valve 4 is opened, allowing the material flushing the pipe to enter the mixing vessel 1 through the pipe. Example 3

[0040] In addition to including all the contents of the previous embodiment, this embodiment has two sets of conveying components 2, which are installed in parallel. The input end of each conveying component 2 is connected to the outlet of the mixing vessel 1, and the output end of each conveying component 2 is connected to the polymerizer 10 and the mixing vessel 1 respectively. Corresponding valves are provided to control the flow direction of the material at the output end.

[0041] In this embodiment, the two sets of conveying components 2 work alternately to complete the pipeline cleaning without stopping the machine. Specifically, when the first set of conveying components 2 is working, a refrigerant is introduced into the interlayer of the conveying pipeline 202 to cool the material, the first valve 3 is open and the second valve 4 is closed; at this time, the second set of conveying components 2 is in the cleaning state, a heating medium is introduced into the interlayer of the conveying pipeline 202 to heat the material, the third valve 5 is closed and the fourth valve 6 is open.

[0042] When the first set of conveying components 2 is being cleaned, a heat medium is introduced into the jacket of the conveying pipe 202 to heat the material, the first valve 3 is closed and the second valve 4 is opened; at this time, the second set of conveying components 2 is in the conveying state, a cold medium is introduced into the jacket of the conveying pipe 202 to cool the material, the third valve 5 is opened and the fourth valve 6 is heated. Example 4

[0043] This embodiment, in addition to including all the contents of the previous embodiment, provides a material flow control method and a pipeline switching control method in Embodiment 3. It includes a controller 7 and a frequency converter 8. The flow meter 203 is electrically connected to the input terminal of the controller 7, the output terminal of the controller 7 is electrically connected to the signal input terminal of the frequency converter 8, and the output terminal of the frequency converter 8 is electrically connected to the motor of the pump 201.

[0044] When the pipeline is in transport mode, the controller 7 controls the flow rate using a PID algorithm. The input signals to the PID controller are the flow rate of the flow meter 203 and the speed signal of the frequency converter 8. When the flow rate setpoint is stable, the speed of the frequency converter 8 is an approximately stable value. When the pipeline is blocked, the PID controller will inevitably increase the speed of the frequency converter 8 in order to maintain the set flow rate. The controller 7 records the speed of the frequency converter 8. When the speed exceeds the warning value, it is determined that the pipeline is blocked. At this time, the controller controls the corresponding valve to switch between the two sets of transport components 2.

[0045] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A conveying device for a para-aramid polymerization solvent system, characterized in that, include: Conveying assembly (2), which is used to convey the para-aramid polymerization solvent system to the polymerizer (10); The conveying assembly (2) includes: A pump (201) is located at the front end of the conveying assembly (2) and is used to provide power for conveying materials; The conveying pipe (202) is connected to the outlet of the pump (201) and the inlet of the aggregator (10). The conveying pipe (202) is a double-layer pipe. The inner layer of the pipe is used to convey materials, and the interlayer of the pipe is connected to an external cold medium source or hot medium source for cooling or heating the materials in the pipe. A flow meter (203) is installed on the conveying pipeline (202) to detect the flow rate of the material in the pipeline; A thermometer (208) is installed on the conveying pipe (202) to detect the temperature of the material inside the pipe.

2. The para-aramid polymerization solvent system conveying device according to claim 1, characterized in that, The inlet end of the cold medium source or hot medium source of the interlayer of the conveying pipeline (202) is located at the end of the material direction, and the outlet end of the cold medium source or hot medium source is located at the beginning of the material direction.

3. The para-aramid polymerization solvent system conveying device according to claim 2, characterized in that, The inlet end of the conveying pipeline (202) for the refrigerant source or the heat source is provided with a refrigerant inlet valve (206) and a heat source inlet valve (207) in parallel, and the outlet end of the conveying pipeline (202) for the refrigerant source or the heat source is provided with a refrigerant outlet valve (204) and a heat source outlet valve (205) in parallel.

4. The para-aramid polymerization solvent system conveying device according to claim 3, characterized in that, It also includes a first valve (3), a second valve (4), and a stirring vessel (1). The stirred tank (1) is used for preparing and storing the para-aramid polymerization solvent system, and its outlet is connected to the inlet of the pump (201). The first valve (3) is installed on the connecting pipe between the output end of the conveying assembly (2) and the inlet of the aggregator (10). The second valve (4) is installed on the connecting pipe between the output end of the conveying assembly (2) and the stirring vessel (1).

5. The para-aramid polymerization solvent system conveying device according to claim 4, characterized in that, There are two sets of conveying components (2), which are installed in parallel. The input end of each conveying component (2) is connected to the outlet of the mixing tank (1), and the output end of each conveying component (2) is connected to the agglomerator (10) and the mixing tank (1) respectively. Corresponding valves are provided to control the flow direction of the material at the output end.

6. The conveying device for a para-aramid polymerization solvent system according to claim 5, characterized in that, It also includes a controller (7) and a frequency converter (8). The flow meter (203) is electrically connected to the input terminal of the controller (7), the output terminal of the controller (7) is electrically connected to the signal input terminal of the frequency converter (8), and the output terminal of the frequency converter (8) is electrically connected to the motor of the pump (201).

7. The para-aramid polymerization solvent system conveying device according to claim 6, characterized in that, The thermometer (208) is electrically connected to the input terminal of the controller (7).

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