Feeding device for PVDF (Polyvinylidene Fluoride) production

Abstract

The utility model relates to the technical field of PVDF (Polyvinylidene Fluoride) production, in particular to a PVDF production feeding device which comprises a feeding pipe, a feeding end and a discharging end are arranged at two ends of the feeding pipe, the discharging end is connected with a polymerization kettle, a jacketed pipe is arranged outside the feeding pipe, a medium inlet and a medium outlet are arranged on the jacketed pipe, and a heat insulation sleeve is arranged outside the jacketed pipe. A heat insulation interlayer is arranged between the heat insulation sleeve and the jacketed pipe and is filled with inert gas; the feeding pipe is obliquely arranged, the lower end of the feeding pipe is a feeding end, and a liquid collecting hopper is arranged at the feeding end. According to the utility model, the product yield, the product quality stability and the production safety and stability are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of PVDF production, in particular to a PVDF production feeding device. Background Art

[0002] The production process of hazardous chemical processes often involves flammable, explosive and toxic hazardous substances. The leakage of these hazardous substances can easily lead to serious environmental disasters and emergencies. At the same time, hazardous chemical production equipment is a complex system. Its production is mainly carried out under adverse conditions such as high temperature and high pressure, which will lead to serious safety problems such as explosions and toxic gas leaks. In recent years, the country has attached great importance to production safety. Therefore, strengthening the chemical industry is crucial to the safe management of the production of hazardous chemicals. According to the "Catalogue of Key Regulated Hazardous Chemical Processes" (2013 complete version) of the former State Administration of Work Safety and the "Interim Provisions on the Supervision and Management of Major Hazard Sources of Hazardous Chemicals" (Order No. 40 of the former State Administration of Work Safety, revised according to Order No. 79 of the State Administration of Work Safety), PVDF polymerization process is a key regulated hazardous chemical process, and the materials used involve VDF, a major hazardous source material. PVDF chemical name: polyvinylidene fluoride, a polymer formed by the polymerization of monomer vinylidene fluoride (VDF). According to the polymerization reaction mechanism: VDF polymerization can be divided into bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and other polymerization methods. In industrial production, suspension polymerization and emulsion polymerization are the main ones. The emulsion polymerization method for preparing PVDF resin is to maintain a certain polymerization pressure and polymerization temperature in a polymerization system in the presence of emulsifiers, initiators, chain transfer agents, stabilizers, etc., and continuously introduce VDF monomers for polymerization reaction. The emulsion polymerization of VDF is actually a precipitation polymerization of a dilute aqueous solution, and its process includes: ① the mass transfer process of VDF monomer dissolving in the aqueous phase; ② dilute aqueous solution polymerization; ③ the polymer product particles are insoluble in water and precipitate from the aqueous phase, and form a dispersion under the action of a dispersant. Emulsion polymerization can be carried out under certain polymerization temperature and faster polymerization speed conditions. The polymerization reaction rate is controlled smoothly, the primary particle size is small, and the product quality is good.

[0003] However, the PVDF polymerization process is an exothermic reaction, and there are risks of over-temperature, over-pressure or stirring cessation in the polymerization process. During the PVDF emulsion polymerization process, the gaseous VDF is lifted from the inlet 0.75MPa(G) and 15°C to the outlet 4.5MPa(G) and 45°C by a diaphragm compressor and transported into the polymerization kettle for reaction. Since the compressor and the polymerization kettle are arranged in different factory buildings and the transportation pipeline is a certain distance away, the temperature is relatively low during transportation in winter, and the gaseous VDF is easy to liquefy, resulting in inaccurate measurement of the subsequent polymerization reaction material VDF by the mass flow meter, pressure and temperature fluctuations in the pipeline, uneven product quality, affecting the normal reaction, resulting in unqualified products, and affecting production efficiency. At the same time, liquid phase feed will also cause the local reaction temperature to be too high, affecting the safety of the reaction. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a PVDF production feeding device, which improves the product yield, product quality stability, and production safety and stability.

[0005] The PVDF production feeding device described in the utility model comprises a feeding pipe, wherein both ends of the feeding pipe are set as a feeding end and a discharging end, the discharging end is connected to a polymerization kettle, a jacket pipe is arranged outside the feeding pipe, a medium inlet and a medium outlet are arranged on the jacket pipe, a heat insulating sleeve is arranged outside the jacket pipe, a heat insulating interlayer is arranged between the heat insulating sleeve and the jacket pipe, and an inert gas is filled in the heat insulating interlayer; the feeding pipe is arranged inclined, the lower end is the feeding end, and a liquid collecting hopper is arranged at the feeding end.

[0006] Preferably, the heat-insulating sleeve is coated with a heat-insulating coating on its exterior, which can further prevent heat from escaping.

[0007] Preferably, a diaphragm compressor is further included, and the diaphragm compressor is connected to the feed end through a high-pressure buffer pipe. The diaphragm compressor can provide stable high-pressure gas to push the raw materials into the polymerization kettle, thereby improving the transmission efficiency and pressure stability of the raw materials.

[0008] Preferably, a pressure safety valve is provided on the high-pressure buffer pipe. In order to ensure the safety of the device, the high-pressure buffer pipe is also equipped with a pressure safety valve. When the pressure in the pipeline exceeds the preset safety value, the pressure safety valve will automatically open to release the excess pressure and protect the device from damage.

[0009] Preferably, a gas flow meter is provided on the feed pipe, and the gas flow meter is arranged close to the polymerization kettle. The gas flow meter can accurately measure the amount of raw materials entering the polymerization kettle, and provide accurate data support for production.

[0010] Preferably, a drain valve is provided on the liquid collecting hopper, so that the liquid in the liquid collecting hopper can be drained regularly to maintain the normal operation of the device.

[0011] Preferably, a coil is provided in the jacket tube, the coil is spirally arranged around the feed pipe, and the two ends of the coil are respectively connected to the medium inlet and the medium outlet. Such a design enables the medium to heat the feed pipe evenly, thereby improving the stability of temperature control.

[0012] Valves can be installed on the pipeline according to the control needs, and the opening and closing of the valve can be conveniently used to control the flow of materials in the corresponding pipeline and adjust the flow of materials.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. A jacket pipe is installed outside the feed pipe to control the feed temperature by adjusting the temperature of the medium in the jacket pipe to prevent VDF from liquefying during transportation;

[0015] 2. The heat-insulating sleeve has a heat-insulating effect, which prevents the heat of the medium in the jacket from escaping, improves the efficiency of the device, prevents heat waste, and saves energy;

[0016] 3. The feed pipe is set at an angle, which can collect the liquid generated in the feed pipe into the liquid collecting hopper in time to prevent the liquid from remaining in the pipeline and affecting production.

[0017] 4. The utility model improves product yield, product quality stability, and production safety and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the PVDF production feeding device of the utility model;

[0019] In the figure: 1. feed pipe; 2. polymerization kettle; 3. jacket pipe; 4. medium inlet; 5. medium outlet; 6. thermal insulation sleeve; 7. thermal insulation interlayer; 8. liquid collecting hopper; 9. diaphragm compressor; 10. high-pressure buffer pipe; 11. pressure safety valve; 12. gas flow meter; 13. drain valve. DETAILED DESCRIPTION

[0020] The present invention will be described clearly and completely below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the PVDF production feeding device described in the utility model includes a feeding pipe 1, wherein both ends of the feeding pipe 1 are set as a feeding end and a discharging end, the discharging end is connected to a polymerization kettle 2, a jacket tube 3 is provided outside the feeding pipe 1, a medium inlet 4 and a medium outlet 5 are provided on the jacket tube 3, a heat insulating sleeve 6 is provided outside the jacket tube 3, a heat insulating interlayer 7 is provided between the heat insulating sleeve 6 and the jacket tube 3, and an inert gas is filled in the heat insulating interlayer 7; the feeding pipe 1 is inclined, and the lower end is the feeding end, and a liquid collecting hopper 8 is provided at the feeding end.

[0022] The exterior of the heat-insulating sleeve 6 is coated with a heat-insulating coating.

[0023] It also includes a diaphragm compressor 9 which is connected to a feed end via a high-pressure buffer pipe 10 .

[0024] A pressure safety valve 11 is provided on the high pressure buffer pipe 10 .

[0025] A gas flow meter 12 is provided on the feed pipe 1 , and the gas flow meter 12 is arranged close to the polymerization kettle 2 .

[0026] The liquid collecting hopper 8 is provided with a drain valve 13 .

[0027] A coil is arranged in the jacket pipe 3, and the coil is spirally arranged around the feed pipe. Two ends of the coil are respectively connected to a medium inlet 4 and a medium outlet 5.

Claims

1. A PVDF production feeding device, comprising a feeding pipe (1), wherein both ends of the feeding pipe (1) are set as a feeding end and a discharging end, and the discharging end is connected to a polymerization kettle (2), characterized in that: A jacket tube (3) is provided outside the feed tube (1), a medium inlet (4) and a medium outlet (5) are provided on the jacket tube (3), a heat insulating sleeve (6) is provided outside the jacket tube (3), a heat insulating interlayer (7) is provided between the heat insulating sleeve (6) and the jacket tube (3), and an inert gas is filled in the heat insulating interlayer (7); the feed tube (1) is arranged in an inclined manner, the lower end of which is the feed end, and a liquid collecting hopper (8) is provided at the feed end.

2. The PVDF production feeding device according to claim 1, characterized in that: The exterior of the heat-insulating sleeve (6) is coated with a heat-insulating coating.

3. The PVDF production feeding device according to claim 1, characterized in that: It also includes a diaphragm compressor (9), which is connected to the feed end via a high-pressure buffer pipe (10).

4. The PVDF production feeding device according to claim 3, characterized in that: A pressure safety valve (11) is provided on the high-pressure buffer pipe (10).

5. The PVDF production feeding device according to claim 1, characterized in that: A gas flow meter (12) is provided on the feed pipe (1), and the gas flow meter (12) is arranged close to the polymerization kettle (2).

6. The PVDF production feeding device according to claim 1, characterized in that: The liquid collecting hopper (8) is provided with a liquid discharge valve (13).

7. The PVDF production feeding device according to claim 1, characterized in that: A coil is arranged inside the jacket pipe (3), and the coil is spirally arranged around the feed pipe. Both ends of the coil are respectively connected to a medium inlet (4) and a medium outlet (5).

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