Heating device of nylon 66 polymerization kettle

Abstract

The utility model belongs to the technical field of chemical equipment, and particularly relates to a heating device of a nylon 66 polymerization kettle. Comprising a biphenyl-diphenyl ether storage tank, a liquid outlet of the biphenyl-diphenyl ether storage tank is connected with a vaporizer, an outlet of the vaporizer is connected with a heating coil of a polymerization kettle, an outlet of the heating coil is connected with a reflux inlet of the vaporizer, and the outlet of the heating coil is further connected with a driving fluid inlet of an injection pump. An outlet of the injection pump is connected to a reflux inlet of the biphenyl-diphenyl ether storage tank through a pipeline; the liquid outlet of the biphenyl-diphenyl ether storage tank is further connected with a backflow pipeline, and the other end of the backflow pipeline is connected to a working fluid inlet of the injection pump. A control system is further included. The gas-phase biphenyl-diphenyl ether is adopted as a heating medium, the requirements for rapid heating and rapid cooling of the polymerization kettle are met, meanwhile, the heating coil of the polymerization kettle can be completely filled with the gas-phase biphenyl-diphenyl ether, uneven heating caused by local flow velocity difference of liquid heat conduction oil is avoided, the phenomenon that materials are locally overheated is reduced, and the product quality is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical equipment, and particularly relates to a heating device for a nylon 66 polymerization kettle. Background Art

[0002] Nylon 66 is the main product in the nylon series. It uses adipic acid and hexamethylenediamine as synthetic raw materials. A certain concentration of nylon 66 salt solution is first formed through the reaction of hexamethylenediamine and adipic acid. The solution is then concentrated and polymerized to remove water from the system to form a large molecular molten polymer. The finished product is then made through processes such as melt casting, cooling, and pelletizing. It has excellent mechanical properties, as well as advantages such as corrosion resistance, oil resistance, temperature resistance, and high modulus. It is widely used in engineering plastics, synthetic fibers and other fields, and plays an important role in automobiles, aerospace, shipbuilding, industrial yarns, and civilian yarns.

[0003] In the production process of nylon 66, the polymerization reaction is carried out in a polymerization kettle in batches. The production process requires continuous removal of water generated by the reaction to promote the polymerization towards macromolecular synthesis. As the molecular weight of the polymer increases, the viscosity of the system increases, and the temperature of the polymerization kettle needs to be continuously increased. The maximum material temperature can reach 280±5°C, and the reaction is mainly divided into a temperature increase and pressure increase section, a pressure holding section, a pressure reduction section, and a vacuum section. The entire process needs to be completed within a certain time. In the initial stage, the reactor material needs to be quickly heated to a certain temperature in a relatively short period of time. In the later pressure reduction stage, due to the reduction of water in the system, the temperature needs to be quickly reduced to prevent the kettle temperature from being too high, causing the material to crack and deteriorate. Currently, the industry mostly uses liquid high-temperature heat transfer oil to heat the polymerization kettle. However, this method has many problems: the liquid heat transfer oil system is large, the total oil volume is large, the temperature rises slowly, and maintaining high temperature for a long time consumes a large amount of natural gas; after the temperature reaches the required temperature, the oil inlet valve is closed, and the hot oil remaining in the coil cannot flow, which will continue to heat the material and cause overheating; the temperature control is delayed and there is a certain deviation, resulting in fluctuations in product quality; local overheating will cause the material to stick to the heating coil, resulting in uneven product viscosity and an increase in black particles; in addition, after the liquid enters the coil, the flow is slow in some areas due to different positions, causing uneven heating of the material.

[0004] Therefore, there is an urgent need for a heating device that can solve the above problems and meet the temperature control requirements of nylon 66 polymerization reaction. Utility Model Content

[0005] In view of the above shortcomings in the prior art, the purpose of the present invention is to provide a heating device for a nylon 66 polymerization kettle, which adopts gaseous biphenyl-biphenyl ether as a heat medium to meet the requirements of rapid heating and cooling of the polymerization kettle. At the same time, the gaseous biphenyl-biphenyl ether can completely fill the heating coil of the polymerization kettle, avoiding uneven heating of the liquid heat transfer oil due to local flow rate differences, reducing the phenomenon of local overheating of the material, thereby reducing the black particle content of the nylon 66 product and improving its viscosity uniformity.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] The heating device of the nylon 66 polymerization kettle includes a biphenyl-biphenyl ether storage tank, a liquid outlet of the biphenyl-biphenyl ether storage tank connected to a vaporizer via a pipeline, the outlet of the vaporizer connected to a heating coil of the polymerization kettle via a pipeline, the outlet of the heating coil connected to a reflux port of the vaporizer via a pipeline, the outlet of the heating coil is also connected to an injection fluid inlet of a jet pump via a pipeline, and the outlet of the jet pump is connected to the reflux port of the biphenyl-biphenyl ether storage tank via a pipeline; the liquid outlet of the biphenyl-biphenyl ether storage tank is also connected to a reflux pipeline, the other end of the reflux pipeline is connected to the working fluid inlet of the jet pump; the gas outlet of the biphenyl-biphenyl ether storage tank is connected to a condenser via a pipeline, and the outlet of the condenser is connected to an exhaust gas treatment device via a pipeline; and a control system is also included.

[0008] An oil supply pump is provided on the liquid outlet pipeline of the biphenyl-biphenyl ether storage tank, and the oil supply pump is electrically connected to the control system.

[0009] A first control valve is provided on the pipeline from the biphenyl-biphenyl ether storage tank to the vaporizer, and a second control valve is provided on the reflux pipeline. The first control valve and the second control valve are electrically connected to the control system respectively.

[0010] A thermal oil heating device is provided in the vaporizer, and the thermal oil heating device is electrically connected to the control system.

[0011] The vaporizer is provided with a liquid level gauge, which is electrically connected to the control system.

[0012] A third control valve is provided on the pipeline from the outlet of the heating coil to the vaporizer, a fourth control valve is provided on the pipeline from the outlet of the heating coil to the jet pump, and a temperature monitoring device is also provided on the outlet pipeline of the heating coil. The third control valve, the fourth control valve and the temperature monitoring device are respectively electrically connected to the control system.

[0013] The working principle of the heating device of the nylon 66 polymerization kettle is as follows:

[0014] When the polymerization kettle needs to be heated, the liquid biphenyl / biphenyl ether in the biphenyl / biphenyl ether storage tank is pumped through the outlet and pipeline to the vaporizer, driven by the oil supply pump. At this time, the first control valve opens and the second control valve closes. A level gauge on the vaporizer monitors the liquid level in real time. When the liquid level reaches 60%, the control system shuts off the oil supply pump and the first control valve, halting the oil supply. The thermal oil heater in the vaporizer activates, heating the liquid biphenyl / biphenyl ether to the vaporization temperature. The resulting vaporized biphenyl / biphenyl ether enters the polymerization kettle's heating coil through the outlet pipeline, where it heats the contents through heat exchange. The heated vaporized biphenyl / biphenyl ether condenses into a liquid phase within the heating coil. The control system then opens the third and first control valves, allowing the liquid biphenyl / biphenyl ether condensed within the heating coil to flow back through the heating coil outlet, the third and first control valves, and finally back to the vaporizer's reflux port, rejoining the vaporization cycle and maintaining stable liquid level, temperature, and pressure within the vaporizer.

[0015] When the polymerization kettle needs to be cooled, the control system closes the third control valve, simultaneously opens the fourth and second control valves, and activates the fuel pump and jet pump. The jet pump's working fluid inlet is connected to the liquid biphenyl-biphenyl ether in the biphenyl-biphenyl ether storage tank via a return line, serving as the working medium. The induced fluid inlet is connected via a pipeline to the vaporous biphenyl-biphenyl ether at the outlet of the heating coil. The jet pump rapidly extracts the vaporous biphenyl-biphenyl ether from the heating coil and returns it to the biphenyl-biphenyl ether storage tank via the jet pump outlet pipeline. When the temperature monitoring device detects that the temperature has dropped to the set value, the control system closes the fourth and second control valves, the fuel pump, and the jet pump, completing the cooling process.

[0016] The small amount of gaseous biphenyl-biphenyl ether remaining in the biphenyl-biphenyl ether storage tank enters the condenser through the gas outlet, is condensed into liquid phase and then flows back to the biphenyl-biphenyl ether storage tank. The uncondensed exhaust gas is purified by the exhaust gas treatment device.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The heating device of the nylon 66 polymerization kettle described in the present invention adopts gaseous biphenyl-biphenyl ether as the heat medium, which can be quickly filled and evenly contacted in the heating coil, thereby significantly improving the heating efficiency; when cooling, the gaseous heat medium in the coil is quickly extracted by the jet pump to stop heating, thereby solving the overheating problem caused by residual liquid heat transfer oil and meeting the temperature change rate requirements of each stage of the polymerization reaction;

[0019] (2) The utility model adopts gaseous biphenyl-biphenyl ether as the heat medium, which can completely fill the heating coil of the polymerization kettle, avoid the uneven heating of the liquid heat transfer oil due to the local flow rate difference, reduce the phenomenon of local overheating of the material and adhesion of the coil, reduce the black particle content of the nylon 66 product, and improve the viscosity uniformity of the nylon 66 product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the heating device of the nylon 66 polymerization kettle described in the present invention;

[0021] In the figure: 1. Biphenyl-biphenyl ether storage tank; 2. Vaporizer; 3. Heating coil; 4. Jet pump; 5. Reflux line; 6. Condenser; 7. Exhaust gas treatment device; 8. Oil supply pump; 9. First control valve; 10. Second control valve; 11. Thermal oil heating device; 12. Liquid level gauge; 13. Third control valve; 14. Fourth control valve; 15. Temperature monitoring device. DETAILED DESCRIPTION

[0022] In order to make the purpose and technical solution of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings.

[0023] Example 1

[0024] like Figure 1 As shown, the heating device of the nylon 66 polymerization kettle includes a biphenyl-biphenyl ether storage tank 1, the liquid outlet of the biphenyl-biphenyl ether storage tank 1 is connected to the vaporizer 2 through a pipeline, the outlet of the vaporizer 2 is connected to the heating coil 3 of the polymerization kettle through a pipeline, the outlet of the heating coil 3 is connected to the reflux port of the vaporizer 2 through a pipeline, the outlet of the heating coil 3 is also connected to the injection fluid inlet of the jet pump 4 through a pipeline, and the outlet of the jet pump 4 is connected to the reflux port of the biphenyl-biphenyl ether storage tank 1 through a pipeline; the liquid outlet of the biphenyl-biphenyl ether storage tank 1 is also connected to the reflux pipeline 5, and the other end of the reflux pipeline 5 is connected to the working fluid inlet of the jet pump 4; the gas outlet of the biphenyl-biphenyl ether storage tank 1 is connected to the condenser 6 through a pipeline, and the outlet of the condenser 6 is connected to the tail gas treatment device 7 through a pipeline; and also includes a control system.

[0025] An oil supply pump 8 is provided on the liquid outlet pipeline of the biphenyl-biphenyl ether storage tank 1 , and the oil supply pump 8 is electrically connected to the control system.

[0026] A first control valve 9 is provided on the pipeline from the biphenyl-biphenyl ether storage tank 1 to the vaporizer 2, and a second control valve 10 is provided on the reflux pipeline 5. The first control valve 9 and the second control valve 10 are electrically connected to the control system respectively.

[0027] The vaporizer 2 is provided with a thermal oil heating device 11 , which is electrically connected to the control system.

[0028] The vaporizer 2 is provided with a liquid level meter 12, which is electrically connected to the control system.

[0029] A third control valve 13 is provided on the pipeline from the outlet of the heating coil 3 to the vaporizer 2, a fourth control valve 14 is provided on the pipeline from the outlet of the heating coil 3 to the jet pump 4, and a temperature monitoring device 15 is also provided on the outlet pipeline of the heating coil 3. The third control valve 13, the fourth control valve 14 and the temperature monitoring device 15 are respectively electrically connected to the control system.

[0030] When working, the specific steps are as follows:

[0031] When the polymerization kettle needs to be heated, the control system opens first control valve 9 and starts oil pump 8, transferring liquid biphenyl-biphenyl ether from biphenyl-biphenyl ether storage tank 1 to vaporizer 2. When the liquid level gauge 12 in vaporizer 2 indicates the liquid level reaches 60%, the control system automatically closes first control valve 9 and oil pump 8, stopping the oil supply. The control system then activates the thermal oil heater 11 in vaporizer 2 to heat and vaporize the liquid biphenyl-biphenyl ether. The resulting gaseous biphenyl-biphenyl ether enters the polymerization kettle's heating coil 3 through the outlet pipeline, beginning to heat the materials within the polymerization kettle. The control system then opens third control valve 13 and first control valve 9, causing the condensed liquid within heating coil 3 to flow back into vaporizer 2 through the outlet of heating coil 3, the third control valve 13, and the first control valve 9, completing a circulation cycle. Heating continues until the materials within the polymerization kettle reach the desired temperature, completing the heating phase.

[0032] When the polymerization kettle needs to be cooled, the control system closes the third control valve 13, stopping the reflux of the gaseous biphenyl-biphenyl ether to the vaporizer 2. At the same time, the fourth control valve 14 and the second control valve 10 are opened, and the oil supply pump 8 and the jet pump 4 are started. The working fluid inlet of the jet pump 4 draws the liquid biphenyl-biphenyl ether in the biphenyl-biphenyl ether storage tank 1 through the reflux line 5, and the induced fluid inlet draws the gaseous biphenyl-biphenyl ether in the heating coil 3. After mixing, the two are refluxed to the biphenyl-biphenyl ether storage tank 1 through the outlet of the jet pump 4. When the temperature monitoring device 15 indicates that the temperature has dropped to the set value, the control system closes the fourth control valve 14, the second control valve 10, the oil supply pump 8, and the jet pump 4, stopping the cooling.

[0033] The small amount of gaseous biphenyl-biphenyl ether remaining in the biphenyl-biphenyl ether storage tank 1 enters the condenser 6 through the gas outlet, is condensed into a liquid phase and then flows back to the biphenyl-biphenyl ether storage tank 1. The remaining tail gas is treated by the tail gas treatment device 7 and then discharged.

Claims

1. A heating device for a nylon 66 polymerization kettle, characterized in that: The invention comprises a biphenyl-biphenyl ether storage tank (1), a liquid outlet of the biphenyl-biphenyl ether storage tank (1) connected to a vaporizer (2) through a pipeline, an outlet of the vaporizer (2) connected to a heating coil (3) of a polymerization kettle through a pipeline, an outlet of the heating coil (3) connected to a reflux port of the vaporizer (2) through a pipeline, an outlet of the heating coil (3) further connected to an injection fluid inlet of a jet pump (4) through a pipeline, and an outlet of the jet pump (4) connected to the reflux port of the biphenyl-biphenyl ether storage tank (1) through a pipeline; a liquid outlet of the biphenyl-biphenyl ether storage tank (1) further connected to a reflux pipeline (5), the other end of the reflux pipeline (5) being connected to a working fluid inlet of the jet pump (4); a gas outlet of the biphenyl-biphenyl ether storage tank (1) connected to a condenser (6) through a pipeline, and an outlet of the condenser (6) connected to an exhaust gas treatment device (7) through a pipeline; and also comprises a control system.

2. The heating device for nylon 66 polymerization kettle according to claim 1, characterized in that: An oil supply pump (8) is provided on the liquid outlet pipeline of the biphenyl-biphenyl ether storage tank (1), and the oil supply pump (8) is electrically connected to the control system.

3. The heating device for nylon 66 polymerization kettle according to claim 1, characterized in that: A first control valve (9) is provided on the pipeline from the biphenyl-biphenyl ether storage tank (1) to the vaporizer (2), and a second control valve (10) is provided on the return pipeline (5). The first control valve (9) and the second control valve (10) are respectively electrically connected to the control system.

4. The temperature raising device for nylon 66 polymerization kettle according to claim 1, characterized in that: A thermal oil heating device (11) is provided in the vaporizer (2), and the thermal oil heating device (11) is electrically connected to the control system.

5. The temperature raising device for nylon 66 polymerization kettle according to claim 1, characterized in that: The vaporizer (2) is provided with a liquid level meter (12), and the liquid level meter (12) is electrically connected to the control system.

6. The temperature raising device for nylon 66 polymerization kettle according to claim 1, characterized in that: A third control valve (13) is provided on the pipeline from the outlet of the heating coil (3) to the vaporizer (2), a fourth control valve (14) is provided on the pipeline from the outlet of the heating coil (3) to the injection pump (4), and a temperature monitoring device (15) is also provided on the outlet pipeline of the heating coil (3). The third control valve (13), the fourth control valve (14) and the temperature monitoring device (15) are respectively electrically connected to the control system.

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