CN101649010A - Spouted bed reactor and method thereof for synthesizing chlorinated polyvinyl chloride by using low-temperature plasmas - Google Patents

Abstract

A spouted bed reactor for low-temperature plasma synthesis of chlorinated polyvinyl chloride and its method, the reactor mainly includes a reactor main body, a gas-solid separation zone and a gas-solid separation device at the top of the reactor main body, etc. A low-temperature plasma generating device, which divides the interior of the reactor body into two parts: a low-temperature plasma reaction zone and a particle downward chlorine migration zone. The method for synthesizing chlorinated polyvinyl chloride in a spouted bed reactor provided by the present invention is to use low-temperature plasma to trigger the rapid chlorination of polyvinyl chloride, so that polyvinyl chloride particles are sprayed in the low-temperature plasma discharge area, and chlorination occurs Reaction: The particles taken out of the low-temperature plasma reaction zone by the gas flow settle in the particle's downward chlorine migration zone to realize the cyclic chlorination of the particles. The invention uses low-temperature plasma means to simultaneously activate chlorine gas and polyvinyl chloride particles at a relatively low temperature, preferably improving production efficiency and product quality.

Description

Spouted bed reactor and method for low temperature plasma synthesis of chlorinated polyvinyl chloride

technical field

The invention relates to a method and a reactor for synthesizing chlorinated polyvinyl chloride, in particular to a spouted bed reactor and a method for synthesizing chlorinated polyvinyl chloride with low-temperature plasma, belonging to the synthesis of a polymer material in the chlor-alkali industry Process and equipment.

Background technique

Chlorinated polyvinyl chloride (CPVC) is a new high-performance plastic. It is made of polyvinyl chloride (PVC) by means of reactive chlorination. The chlorine content increases from 56.8% of PVC to 60%-70%, theoretically up to 73.2%. Generally, CPVC has a chlorine content of 61. %-68%. Due to the increase in the content of polar elements, CPVC exhibits a series of characteristics that are much superior to PVC: the Vicat softening temperature reaches 90-125°C, after treatment, the maximum use temperature is 110°C, and the long-term use temperature is 95°C, which has better Weather resistance, corrosion resistance and aging resistance.

CPVC has high cost performance, broad market prospects and great application value; it can be widely used in cold and hot water pipelines, building materials and other fields. At the same time, the development of CPVC projects can balance the excess chlorine in the chlor-alkali industry, which is of great significance to the development of the recycling industry.

The existing CPVC production processes mainly include solution method (eliminated), water phase suspension method, gas-solid phase chlorination method, and liquid chlorine chlorination method. The aqueous phase suspension method is a production method commonly adopted by major companies.

Because the aqueous phase CPVC synthesis process still has the disadvantages of complex product separation, serious discharge of reaction waste liquid, environmental pollution, and dirty production environment, the gas-solid phase chlorination process has attracted widespread attention due to its clean production and easy control.

Low-temperature plasma CPVC synthesis technology is a new and promising CPVC synthesis approach. A method of low-temperature plasma chlorination of polymers (CN1749285A) invented by Meng Yuedong and Xiong Xinyang of the Institute of Plasma Physics, Chinese Academy of Sciences. Its characteristics Because the chlorination process of high molecular polymer is completed in the same plasma reactor, the two chlorine content results of PVC chlorination as an example are only 59% and 64.5%. In an article titled "Preparation of Chlorinated Polyvinyl Chloride by Low-temperature Plasma Gas Phase Method" published by Xiong Xinyang in 2006, the chlorination of PVC was realized in a traditional fluidized bed, but the chlorination result could only reach 59.4%.

Contents of the invention

The purpose of the present invention is to aim at the strong heat release in the PVC chlorination process, the PVC particles are easy to bond, and it is necessary to realize the characteristics of the decoupling of the chlorination and chlorine migration process. By adding a low-temperature plasma discharge area in the spouted bed reactor, a Realize the decoupling operation mode of PVC chlorination and chlorine migration process, and then achieve the purpose of improving PVC chlorination efficiency and product quality.

In order to achieve the above object, the present invention adopts the following technical solutions:

A spouted bed reactor for low-temperature plasma synthesis of chlorinated polyvinyl chloride, the spouted bed reactor includes a reactor main body 7, a raw material gas inlet 13, a raw material gas distributor 8 and a product outlet arranged at the lower part of the reactor main body The feed port 10, the polyvinyl chloride raw material feed port 12 arranged on the upper part of the reactor main body, the gas-solid separation zone 2 and the gas-solid separation device 1 arranged on the top of the reactor main body, are characterized in that: inside the reactor main body A low-temperature plasma generating device 4 is provided, which divides the interior of the reactor body into two parts: a low-temperature plasma reaction zone 5 and a particle downward chlorine migration zone 6, and a particle downward baffle is set on the upper part of the low-temperature plasma generating device 3. A loose gas distributor 9 is installed at the lower part of the low-temperature plasma generator. The loose gas distributor is connected to the inner wall of the reactor main body and the raw material gas distributor 8, and a loose gas inlet 11 is provided at the bottom of the reactor main body.

In the device provided by the present invention, it is characterized in that: the plasma generated by the low-temperature plasma generator is dielectric barrier discharge plasma, pulse plasma, radio frequency plasma or microwave plasma; the low-temperature plasma The generating device adopts intermittent discharge or continuous discharge.

A kind of method for synthesizing chlorinated polyvinyl chloride by low-temperature plasma provided by the invention is characterized in that the method comprises the steps:

1) The polyvinyl chloride granular raw material is loaded into the reactor from the feeding port, and the average particle diameter of the polyvinyl chloride granular raw material is 50-250 microns;

2) The raw material gas flows in from the raw material gas inlet 13, enters the low-temperature plasma reaction zone 5 through the raw material gas distributor 8, and drives the polyvinyl chloride particles to go upward, and activates the polyvinyl chloride particles and chlorine gas through the low-temperature plasma reaction zone, and a chlorination reaction occurs , the upward residence time of polyvinyl chloride particles in the low temperature plasma reaction zone is 1s~60s, the operating temperature is 60~120℃, and the operating pressure is 0.1~1.5atm;

3) The chlorinated polyvinyl chloride particles obtained by the reaction and the unreacted polyvinyl chloride particles are blocked at the particle downward baffle 3 and stop going upward, and enter the particle downward chlorine migration zone 6 to settle downward, and the particles are in countercurrent contact with the raw material gas during the downward process , to carry out the chlorine migration process, the operating temperature is maintained at 60-120 ° C, and the operating pressure is 0.1-1.5 atm;

4) The loosening gas flows in from the loosening gas inlet 11, and enters the chlorine migration area of the particles through the loosening gas distributor, so that the settled polyvinyl chloride particles and chlorinated polyvinyl chloride particles are loosened, and flow to the raw material gas distributor under the action of gravity 8, it is brought into the low-temperature plasma reaction zone 5 again by the inflowing raw material gas to realize the chlorination of particles in circulation;

5) The gas after the reaction enters the gas-solid separation zone 2, and the solid particles separated by sedimentation are returned to the reactor for cyclic chlorination. After the HCl is removed, the tail gas is mixed with the raw material gas, and some fine particles that are difficult to separate by gravity sedimentation are passed through the gas Solid separation device 1 separates;

6) When the chlorine content of the product granules meets the process requirements, stop feeding the feed gas and loosening gas, and use hot argon to purge the product, then remove the product granules from the product outlet 10 out of the reactor.

In the method of the present invention, it is characterized in that, the raw material gas is chlorine or a mixed gas of chlorine and inert gas, or a mixed gas of chlorine, nitrogen and hydrogen chloride, or a mixed gas of chlorine, inert gas and hydrogen chloride; The loosening gas is argon or nitrogen.

Compared with the prior art, the present invention has the following advantages:

①Using low-temperature plasma means to simultaneously activate chlorine gas and polyvinyl chloride particles at a relatively low temperature to improve production efficiency and product quality; Smaller than pollution, it is a cleaner new synthesis process; ③Using a spouted bed reactor, it is possible to realize the uplink rapid chlorination of polyvinyl chloride particles in the low temperature plasma reaction zone and the downlink chlorine migration zone of the particles in the same reactor The slow sedimentation chlorine migration; ④Using the spouted bed reactor, the dispersion of the gas-solid phase fluidization of polyvinyl chloride particles can be realized, and it can be operated at a high particle density, and it is easy to transfer heat. ⑤This process decouples the two processes of polyvinyl chloride chlorination and chlorine migration and homogenization in different areas of the reactor, and utilizes the characteristics of low-temperature plasma that can generate ultraviolet light. Outside the low-temperature plasma reaction area, the particles settle A slow chlorination reaction can still occur during the migration process, which improves the reaction efficiency. ⑥The overall scale of the low-temperature plasma reaction zone is small, and does not require a large amount of raw material gas for transportation; the particles are less affected by the electric field, and can be operated at a high particle density. The residence time of the particles in the plasma area is short, which can weaken the damage and etching effect of the plasma on the particles, and is beneficial to the improvement of product quality.

Description of drawings

Fig. 1 is a flow chart of the first embodiment provided by the present invention and a schematic diagram of a low-temperature plasma CPVC synthesis spouted bed device.

Among them, 1-gas-solid separation device; 2-gas-solid separation zone; 3-particle downflow baffle; 4-low temperature plasma generator; 5-low temperature plasma reaction zone; 6-particle downflow chlorine migration zone; 7-reaction 8-Raw material gas distributor; 9-Loose gas distributor; 10-Product outlet; 11-Loose gas inlet; 12-PVC raw material inlet; 13-Raw gas inlet.

Detailed ways

The present invention will be further described below in conjunction with the embodiments and accompanying drawings, without any limitation to the present invention.

Fig. 1 is a flow chart of an embodiment provided by the present invention and a schematic diagram of the structure and process flow of a low-temperature plasma CPVC synthesis spouted bed reactor. The spouted bed reactor comprises a reactor main body 7, a raw material gas inlet 13, a raw material gas distributor 8 and a product discharge port 10 arranged at the lower part of the reactor main body, and a polyvinyl chloride raw material inlet arranged at the upper part of the reactor main body 12. The gas-solid separation zone 2 and the gas-solid separation device 1 are arranged on the top of the reactor body, and a low-temperature plasma generator 4 is installed inside the reactor body, and the low-temperature plasma generator divides the interior of the reactor body into low-temperature plasma There are two parts, the reaction zone 5 and the particle downward chlorine migration zone 6. The particle downward baffle 3 is arranged on the upper part of the low-temperature plasma generator, and the loose gas distributor 9 is arranged on the lower part of the low-temperature plasma generator. The loose gas distributor and the reactor main body The inner wall is connected to the raw material gas distributor 8, and a loose gas inlet 11 is provided at the bottom of the reactor main body. The outside of the reactor is heated by winding a heating tape, and the reaction temperature is controlled by an automatic temperature control device.

The plasma generated by the low temperature plasma generator is dielectric barrier discharge plasma, pulse plasma, radio frequency plasma or microwave plasma, and the input power of the low temperature plasma power supply is 10-100W. The low-temperature plasma generating device adopts intermittent discharge or continuous discharge.

The method for synthesizing chlorinated polyvinyl chloride by low-temperature plasma provided by the invention, the specific steps of the method are as follows:

1) The polyvinyl chloride granular raw material is loaded into the reactor from the feeding port, with an average particle size of 50-250 microns;

2) The raw material gas flows in from the raw material gas inlet 13, enters the low-temperature plasma reaction zone 5 through the raw material gas distributor 8, and drives the polyvinyl chloride particles to go upward, and activates the polyvinyl chloride particles and chlorine gas through the low-temperature plasma reaction zone, and a chlorination reaction occurs , the upward residence time of polyvinyl chloride particles in the low temperature plasma reaction zone is 1s~60s, the operating temperature is 60~120℃, and the operating pressure is 0.1~1.5atm;

3) The chlorinated polyvinyl chloride particles obtained by the reaction and the unreacted polyvinyl chloride particles are blocked at the particle downward baffle 3 and stop going upward, and enter the particle downward chlorine migration zone 6 to settle downward, and the particles are in countercurrent contact with the raw material gas during the downward process , to carry out the chlorine migration process, the operating temperature is maintained at 60-120 ° C, and the operating pressure is 0.1-1.5 atm;

4) The loosening gas flows in from the loosening gas inlet 11, and enters the chlorine migration area of the particles through the loosening gas distributor, so that the settled polyvinyl chloride particles and chlorinated polyvinyl chloride particles are loosened, and flow to the raw material gas distributor under the action of gravity 8, it is brought into the low-temperature plasma reaction zone 5 again by the inflowing raw material gas to realize the chlorination of particles in circulation;

5) The gas after the reaction enters the gas-solid separation zone 2, and the solid particles separated by sedimentation are returned to the reactor for cyclic chlorination. After the HCl is removed, the tail gas is mixed with the raw material gas, and some fine particles that are difficult to separate by gravity sedimentation are passed through the gas Solid separation device 1 separates;

6) When the chlorine content of the product granules meets the process requirements, stop feeding the feed gas and loosening gas, and use hot argon to purge the product, then pour the product granules out of the reactor from the product outlet 10 .

The method for preparing chlorinated polyvinyl chloride in a low-temperature plasma spouted bed is characterized in that the raw material gas is chlorine or a mixed gas of chlorine and an inert gas, or a mixed gas of chlorine, nitrogen and hydrogen chloride, or chlorine, A mixed gas of inert gas and hydrogen chloride; the loosening gas is argon or nitrogen.

Example 1

The reactor was operated at atmospheric pressure. PVC particles with an average particle size of 250 μm are loaded into the reactor at the polyvinyl chloride raw material feed port 12, and the feed mass is 5 g. The input power of the low temperature plasma power supply is 50W. The reaction temperature was 100°C. Argon is used as the loosening gas, which is introduced from the loosening gas inlet 11, and the PVC particles deposited at the bottom of the reactor are dispersed under the action of the loosening gas; pure chlorine gas is input from the raw material gas inlet 13, and the PVC particles are entrained at a relatively high flow rate and pass through quickly Low-temperature plasma reaction zone 5 activates chlorine gas and PVC particles, and chlorination reaction occurs, and the residence time is 60s. The chlorinated polyvinyl chloride particles obtained by the reaction and the unreacted polyvinyl chloride particles go up to the particle downstream baffle plate 3, and return to the particle downstream chlorine migration zone 6 under the action of the baffle plate, and in the particle downstream chlorine migration zone 6, the chlorination The mixed gas of polyvinyl chloride particles and unreacted polyvinyl chloride particles and chlorine gas and argon gas flows downward at a slow speed to realize the process of chlorine migration.

After 3 hours of circulating operation, the obtained chlorinated polyvinyl chloride granular product was removed from the product discharge port 10, and the chlorine content was 68.9% as measured by the oxygen cylinder combustion method, meeting the production requirements of CPVC.

Example 2

The reactor was operated at atmospheric pressure. PVC particles with an average particle size of 150 μm are loaded into the reactor at the polyvinyl chloride raw material feed port 12, and the feed mass is 5 g. The input power of the low temperature plasma power supply is 50W. The reaction temperature was 100°C. Using argon as the loosening gas, it is introduced from the loosening gas inlet 11, and the PVC particles deposited on the bottom of the reactor are dispersed under the action of the loosening gas; the mixed gas of chlorine and argon is input from the raw material gas inlet 13, and the chlorine gas fraction is 80%. Entrained PVC particles pass through the low-temperature plasma reaction zone 5 quickly at a relatively high flow rate, activating chlorine gas and PVC particles, and chlorination reaction occurs, and the residence time is 60s. The PVC granules go up to the baffle plate 3, and flow back to the chlorine migration area 6 under the action of the baffle. The mixed gas of argon goes down slowly in cross-flow to realize the process of chlorine migration.

After 3 hours of circulating operation, the obtained CPVC product was removed from the product outlet 10, and the chlorine content was 67.0% as measured by the oxygen bottle combustion method, meeting the production requirements of CPVC.

Example 3

The reactor was operated at atmospheric pressure. PVC particles with an average particle size of 50 μm are loaded into the reactor at the polyvinyl chloride raw material feed port 12, and the feed mass is 5 g. The input power of the low temperature plasma power supply is 100W. The reaction temperature was 60°C. Argon is used as the loosening gas, which is introduced from the loosening gas inlet 11, and the PVC particles deposited on the bottom of the reactor are dispersed under the action of the loosening gas; pure chlorine gas is input from the raw material gas inlet 13, and the PVC particles are entrained at a relatively high flow rate to move up quickly Through the low-temperature plasma reaction zone 5, chlorine gas and PVC particles are activated, and a chlorination reaction occurs, and the residence time is 10s. The PVC granules go up to the baffle plate 3, and flow back to the chlorine migration zone 6 under the action of the baffle plate. The mixed gas of argon goes down slowly in cross-flow to realize the process of chlorine migration.

After 4 hours of circulating operation, the obtained CPVC product was removed from the product discharge port, and the chlorine content was 65.7% as measured by the oxygen bottle combustion method, which met the production requirements of CPVC.

Example 4

The reactor was operated at 1.5 atm absolute pressure. PVC particles with an average particle size of 150 μm are loaded into the reactor at the polyvinyl chloride raw material feed port 12, and the feed mass is 5 g. The input power of the low temperature plasma power supply is 100W. The reaction temperature was 90°C. Argon is used as the loosening gas, which is introduced from the loosening gas inlet 11, and the PVC particles deposited at the bottom of the reactor are dispersed under the action of the loosening gas; pure chlorine gas is input from the raw material gas inlet 13, and the PVC particles are entrained at a relatively high flow rate and pass through quickly In the low-temperature plasma discharge area, chlorine gas and PVC particles are activated, and a chlorination reaction occurs, and the residence time is 20s. The PVC granules go up to the baffle plate 3, and flow back to the chlorine migration zone 6 under the action of the baffle plate. The mixed gas of argon goes down slowly in cross-flow to realize the process of chlorine migration.

After 2.5 hours of circulating operation, the obtained CPVC product was removed from the product discharge port 10, and the chlorine content was 69.0% as measured by the oxygen bottle combustion method, meeting the production requirements of CPVC.

Example 5

The reactor was operated at an absolute pressure of 0.5 atm. The PVC particles with an average particle size of 200 μm are loaded into the reactor at the feed port 12, and the feed mass is 5 g. The input power of the low-temperature plasma reaction zone 6 is 50W. The reaction temperature was 120°C. Argon is used as the loosening gas, and it is introduced from the gas path 11, and the PVC particles deposited at the bottom of the reactor are dispersed under the action of the loosening gas; pure chlorine gas is input from the gas path 13, and the PVC particles are entrained at a relatively high flow rate to fluidize and move upward quickly Through the low-temperature plasma discharge area, chlorine gas and PVC particles are activated, and a chlorination reaction occurs, and the residence time is 10s. The PVC particles go up to the particle baffle plate 5, and flow back to the settled chlorine migration zone 4 under the action of the baffle plate. In the down-going bed, they cross-flow with the mixed gas of chlorine gas and argon gas and descend slowly to realize the process of chlorine migration.

After 4 hours of circulating operation, the obtained CPVC product was removed from the discharge port 10, and the chlorine content was 67.5% as measured by the oxygen cylinder combustion method, which met the production requirements of CPVC.

Example 6

The reactor was operated at an absolute pressure of 0.1 atm. The PVC particles with an average particle size of 250 μm are loaded into the reactor at the feed port 12, and the feed mass is 5 g. The input power of the low-temperature plasma reaction zone 6 is 10W. The reaction temperature was 100°C. Argon is used as the loosening gas, and it is introduced from the gas path 11, and the PVC particles deposited at the bottom of the reactor are dispersed under the action of the loosening gas; pure chlorine gas is input from the gas path 13, and the PVC particles are entrained at a relatively high flow rate to fluidize and move upward quickly Through the low-temperature plasma discharge area, chlorine gas and PVC particles are activated, and a chlorination reaction occurs, and the residence time is 5s. The PVC particles go up to the particle baffle plate 5, and flow back to the settled chlorine migration zone 4 under the action of the baffle plate. In the down-going bed, they cross-flow with the mixed gas of chlorine gas and argon gas and descend slowly to realize the process of chlorine migration.

After 4 hours of circulating operation, the obtained CPVC product was removed from the discharge port 10, and measured by the oxygen bottle combustion method, the chlorine content was 66.2%, which met the production requirements of CPVC.

Claims (4)

1. A spouted bed reactor for low-temperature plasma synthesis of chlorinated polyvinyl chloride, the spouted bed reactor comprises a reactor main body (7), a raw material gas inlet (13) arranged at the reactor main body bottom, a raw material gas Distributor (8) and product discharge port (10), polyvinyl chloride raw material feed port (12) arranged on the upper part of the reactor main body, gas-solid separation zone (2) and gas-solid separation device arranged on the top of the reactor main body (1), characterized in that: a low-temperature plasma generating device (4) is provided inside the reactor body, and the low-temperature plasma generating device divides the interior of the reactor body into a low-temperature plasma reaction zone (5) and a particle There are two parts of the downward chlorine migration area (6). A particle downward baffle (3) is arranged on the upper part of the low-temperature plasma generating device, and a loose gas distributor (9) is arranged on the lower part of the low-temperature plasma generating device. The loose gas distributor and the reactor The inner wall of the main body is connected with the raw material gas distributor (8), and a loose gas inlet (11) is provided at the bottom of the main body of the reactor. 2. A spouted bed reactor for synthesizing chlorinated polyvinyl chloride with low-temperature plasma according to claim 1, characterized in that: the plasma generated by the low-temperature plasma generator is dielectric barrier discharge plasma, Pulse plasma, radio frequency plasma or microwave plasma; the low-temperature plasma generating device adopts intermittent discharge or continuous discharge. 3. A method for synthesizing chlorinated polyvinyl chloride using a spouted bed reactor as claimed in claim 1, characterized in that the method comprises the steps: 1) The polyvinyl chloride granular raw material is loaded into the reactor from the feeding port, and the average particle diameter of the polyvinyl chloride granular raw material is 50-250 microns; 2) The raw material gas flows in from the raw material gas inlet (13), enters the low-temperature plasma reaction zone (5) through the raw material gas distributor (8), drives the polyvinyl chloride particles upward, and activates the polyvinyl chloride particles and Chlorine gas, chlorination reaction occurs, the residence time of polyvinyl chloride particles ascending in the low temperature plasma reaction zone is 1s~60s, the operating temperature is 60~120℃, and the operating pressure is 0.1~1.5atm; 3) The chlorinated polyvinyl chloride particles obtained by the reaction and the unreacted polyvinyl chloride particles are blocked at the particle downward baffle (3) and stop going upward, and enter the particle downward chlorine migration area (6) to settle downward, and the particles are in the process of descending with The raw material gas is contacted in countercurrent to carry out the process of chlorine migration, the operating temperature is maintained at 60-120 °C, and the operating pressure is 0.1-1.5 atm; 4) The loosening gas flows in from the loosening gas inlet (11), and enters the particle downward chlorine migration area through the loosening gas distributor, so that the settled polyvinyl chloride particles and chlorinated polyvinyl chloride particles are loosened, and flow to the raw material gas under the action of gravity On the distributor (8), it is brought into the low-temperature plasma reaction zone (5) by the inflowing raw material gas again, so as to realize the cyclic chlorination of the particles; 5) The gas after the reaction enters the gas-solid separation zone (2), and the solid particles separated by sedimentation return to the reactor for cyclic chlorination. After the tail gas is removed from HCl, it is mixed with the raw material gas, and some fine particles that are difficult to separate by gravity sedimentation, Separation through the gas-solid separation device (1); 6) When the chlorine content of the product granules meets the process requirements, stop feeding the feed gas and loosening gas, and use hot argon to purge the product, and then remove the product granules from the product outlet (10) out of the reactor. 4. The method for synthesizing chlorinated polyvinyl chloride in a spouted bed reactor according to claim 3, wherein the raw material gas is chlorine or a mixed gas of chlorine and inert gas, or a mixture of chlorine, nitrogen and hydrogen chloride gas, or a mixed gas of chlorine, inert gas and hydrogen chloride; the loosening gas is argon or nitrogen.

Images