CN115646384A - A device for acrylonitrile-styrene polymerization - Google Patents

Abstract

The invention relates to a device for acrylonitrile-styrene polymerization reaction, wherein a first discharge hole of a first-stage reactor is connected with a feed inlet at the top of the first-stage reactor through a first forced reflux pipeline and is connected with a feed inlet in the middle of the first-stage reactor through a second forced reflux pipeline; the first forced return pipeline is connected with the raw material supply pipeline and is provided with a first mixer; the second discharge hole of the primary reactor is connected with the secondary reactor through a first discharge pipeline; a first discharge hole of the secondary reactor is connected with a feed inlet at the top of the secondary reactor through a third forced reflux pipeline and is connected with a feed inlet in the middle of the secondary reactor through a fourth forced reflux pipeline; the third forced reflux pipeline is connected with the first discharge pipeline and is provided with a second mixer; a second discharge hole of the secondary reactor is connected with the primary devolatilization device through a second discharge pipeline; the discharge hole of the first-stage devolatilization device is connected with the second-stage devolatilization device through a third discharge pipeline; the discharge hole of the secondary devolatilization device is connected with a fourth discharge pipeline.

Description

A device for acrylonitrile-styrene polymerization

Technical Field

The invention belongs to the technical field of chemical devices, and particularly relates to a device for acrylonitrile-styrene polymerization.

Background

Styrene-acrylonitrile copolymer (SAN), also known AS a thermoplastic resin, is colorless and transparent, and has excellent gloss, high temperature resistance, chemical medium resistance, hardness, dimensional stability, and high load-bearing capacity and rigidity. The method is widely applied to the fields of household appliances, buildings, automobiles and the like.

The polymerization of acrylonitrile and styrene is subject to emulsion polymerization, suspension polymerization, continuous bulk polymerization. However, the emulsion polymerization method is being eliminated due to the complex production process and high cost. The products produced by the suspension emulsion polymerization method have poor transparency and can only be used for ABS resin blended with base materials. The styrene-acrylonitrile polymer prepared by the continuous bulk polymerization method has the characteristics of excellent glossiness, high temperature resistance, chemical medium resistance, excellent hardness, dimensional stability, higher bearing capacity, rigidity and the like, and is the most common synthetic method of the styrene-acrylonitrile polymer in the industry. The continuous bulk polymerization method generally adopts a thermal initiation continuous bulk polymerization technology, and takes styrene and acrylonitrile as monomers, and a small amount of ethylbenzene is added as a diluting solvent to synthesize the styrene-acrylonitrile polymer. However, the current continuous bulk polymerization process generally has the following problems: 1. low conversion, which means that the back-end needs to consume more energy to purify the product and recover the unreacted starting materials. 2. The yellowness index increases, thereby affecting the quality of the product. 3. The system temperature increases and the devolatilization difficulty increases.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the device for acrylonitrile-styrene polymerization reaction, which can improve the acrylonitrile-styrene polymerization reaction effect and the product quality.

In order to solve the technical problems, the invention adopts the following technical scheme: an apparatus for acrylonitrile-styrene polymerization, comprising: the device comprises a primary reactor, a secondary reactor, a primary devolatilization device, a secondary devolatilization device, a first mixer and a second mixer; the first discharge hole at the bottom of the primary reactor is connected with the feed inlet at the top of the primary reactor through a first forced reflux pipeline, and is connected with the feed inlet in the middle of the primary reactor through a second forced reflux pipeline; the first forced return pipeline is connected with the raw material supply pipeline and is provided with the first mixer; a second discharge hole at the bottom of the primary reactor is connected with a feed inlet at the top of the secondary reactor through a first discharge pipeline; the first discharge hole at the bottom of the secondary reactor is connected with the feeding hole at the top of the secondary reactor through a third forced reflux pipeline and is connected with the feeding hole at the middle part of the secondary reactor through a fourth forced reflux pipeline; the third forced return pipeline is connected with the first discharge pipeline and is provided with the second mixer; a second discharge hole at the bottom of the secondary reactor is connected with a feed inlet of the primary devolatilization device through a second discharge pipeline; a discharge hole at the bottom of the primary devolatilization device is connected with a feeding hole of the secondary devolatilization device through a third discharge pipeline; and a discharge hole at the bottom of the secondary devolatilization device is connected with a fourth discharge pipeline and is used for outputting the product.

In a specific embodiment, the first discharge port at the bottom of the primary reactor is connected with the first forced reflux pipeline and the second forced reflux pipeline through a first forced reflux pump, the second discharge port at the bottom of the primary reactor is connected with the first discharge pipeline through a first discharge pump, the first discharge port at the bottom of the secondary reactor is connected with the third forced reflux pipeline and the fourth forced reflux pipeline through a second forced reflux pump, the second discharge port at the bottom of the secondary reactor is connected with the second discharge pipeline through a second discharge pump, the discharge port at the bottom of the primary devolatilizer is connected with the third discharge pipeline through a third discharge pump, and the discharge port at the bottom of the secondary devolatilizer is connected with the fourth discharge pipeline through a fourth discharge pump.

In a specific embodiment, the top of the first-stage reactor is connected with the inlet end of a first condenser through a first pipeline, the outlet end of the first condenser is connected with the inlet end of a first reflux tank, the outlet end of the first reflux tank is connected with the first-stage reactor through a first reflux pump, the top of the second-stage reactor is connected with the inlet end of a second condenser through a second pipeline, the outlet end of the second condenser is connected with the inlet end of a second reflux tank, and the outlet end of the second reflux tank is connected with the second-stage reactor through a second reflux pump.

In a specific embodiment, the included angle between the axis of the first condenser and the horizontal line is 5-90 degrees, and the included angle between the axis of the second condenser and the horizontal line is 5-90 degrees.

In one embodiment, the first line is connected to the exhaust gas treatment device via a first trap and the second line is connected to the exhaust gas treatment device via a second trap.

In one embodiment, a first control valve is disposed on a pipeline connecting the first steam trap and the exhaust gas treatment device, and a second control valve is disposed on a pipeline connecting the second steam trap and the exhaust gas treatment device.

In a specific embodiment, the primary devolatilizer and the secondary devolatilizer are both connected to a vacuum device through a monomer recovery device, and the monomer recovery device is configured to recover a monomer generated by devolatilization of the primary devolatilizer and a monomer generated by devolatilization of the secondary devolatilizer in a vacuum environment provided by the vacuum device, and recover a monomer from a condensed liquid in the vacuum device.

In one embodiment, the monomer recovery unit is connected to the feed supply line.

In a particular embodiment, the vacuum device is coupled to the exhaust treatment device.

In a specific embodiment, a first preheater is arranged at the top of the secondary devolatilizer, the third discharge pipeline is connected with the feeding port of the secondary devolatilizer through the first preheater, a second preheater is arranged at the top of the primary devolatilizer, and the second discharge pipeline is connected with the feeding port of the primary devolatilizer through the second preheater.

In a specific embodiment, a stirring device is disposed in both the primary reactor and the secondary reactor, the stirring device comprises a radial flow stirrer and an axial flow stirrer, or a mixed stirrer comprising a radial flow stirring part and an axial flow stirring part.

In one embodiment, the paddle pattern of the stirring device comprises: the multi-layer four-blade flat blade, the multi-layer four-blade inclined blade, the multi-layer two-blade flat blade, the multi-layer two-blade inclined blade, the multi-layer three-blade turbine blade, the anchor blade, the ribbon blade, the screw blade or the combination of the above stirring type blades.

In a specific embodiment, when the stirring device comprises the radial flow stirrer and the axial flow stirrer, the radial flow stirrer and the axial flow stirrer are arranged at intervals up and down.

In an embodiment, the feeding direction of the first forced reflux pipeline at the feeding port at the top of the primary reactor is vertical downward, and the feeding direction of the first forced reflux pipeline after feeding is the same as the flow direction of the stream formed by stirring at the feeding port at the top of the primary reactor by the stirring device in the primary reactor, the feeding direction of the third forced reflux pipeline at the feeding port at the top of the secondary reactor is vertical downward, and the feeding direction of the third forced reflux pipeline after feeding is the same as the flow direction of the stream formed by stirring at the feeding port at the top of the secondary reactor by the stirring device in the secondary reactor.

In a specific embodiment, the feeding position of the second forced return line is below the liquid levels of the reaction liquid and the products in the first-stage reactor, the feeding direction of the second forced return line is horizontal direction, the feeding position of the fourth forced return line is below the liquid levels of the reaction liquid and the products in the second-stage reactor, and the feeding direction of the fourth forced return line is horizontal direction.

In a specific embodiment, the feeding position of the second forced reflux pipeline is one tenth to four fifths of the height of the liquid level in the primary reactor from the lower head of the primary reactor, and the feeding position of the fourth forced reflux pipeline is one tenth to four fifths of the height of the liquid level in the secondary reactor from the lower head of the secondary reactor.

In one embodiment, the feeding position of the second forced reflux pipeline is two fifths to seven tenths of the height of the liquid level in the primary reactor from the lower head of the primary reactor, and the feeding position of the fourth forced reflux pipeline is two fifths to seven tenths of the height of the liquid level in the secondary reactor from the lower head of the secondary reactor.

In a specific embodiment, the number of the second and/or fourth forced return lines is multiple.

In a specific embodiment, the number of the second forced return lines is an even number, and the number of the fourth forced return lines is an even number.

In a specific embodiment, the outside of the primary reactor, the outside of the secondary reactor, the outside of the first devolatilizer and the outside of the second devolatilizer are all sleeved with jacket portions, and heat tracing media are arranged in the jacket portions.

In one embodiment, the heat trace medium comprises steam or hot oil.

In one particular embodiment, the feedstock comprises: styrene, acrylonitrile, solvent and molecular weight regulator.

In one particular embodiment, the solvent comprises: toluene, butylbenzene, benzene and/or xylene and all isomers of xylene.

In a particular embodiment, the solvent is toluene.

In a specific embodiment, the temperature in the first stage reactor and the temperature in the second stage reactor are both 100 to 180 degrees celsius.

In one embodiment, the temperature in the primary reactor and the temperature in the secondary reactor are both 130 to 170 degrees Celsius.

In a specific embodiment, the temperature in the primary devolatilizer is from 100 to 180 degrees celsius, the pressure in the primary devolatilizer is from 1 to 50 kilopascals, the operating temperature of the secondary devolatilizer is from 200 to 300 degrees celsius, and the pressure in the secondary devolatilizer is from 1 to 50 kilopascals.

In one embodiment, the temperature in the primary devolatilizer is 130 to 170 ℃, the pressure in the primary devolatilizer is 5 to 39 kpa, the temperature in the secondary devolatilizer is 220 to 280 ℃, and the pressure in the secondary devolatilizer is 5 to 39 kpa.

Compared with the prior art, the invention has the beneficial effects that:

the method can improve the polymerization effect of the acrylonitrile-styrene, obtain high-quality acrylonitrile-styrene polymer products, save energy consumption, and has good economy and wide market prospect.

Drawings

FIG. 1 shows a schematic structural view of one embodiment of an apparatus for acrylonitrile-styrene polymerization according to the present invention;

FIG. 2 is a schematic view showing the effect of temperature and pressure upon removal of acrylonitrile in the primary devolatilizer of one embodiment of the apparatus for polymerization of acrylonitrile-styrene of the present invention.

Wherein, 1-a first-stage reactor; 2-a secondary reactor; 3-first-stage devolatilization device; 4-a secondary devolatilization device; 5-a first mixer; 6-a second mixer; 7-a first forced return line; 8-a second forced return line; 9-raw material supply line; 10-a first discharge line; 11-a third forced return line; 12-a fourth forced return line; 13-a second discharge line; 14-a third discharge line; 15-a fourth discharge line; 16-a first forced reflux pump; 17-a first discharge pump; 18-a second forced reflux pump; 19-a second discharge pump; 20-a third discharge pump; 21-a fourth discharge pump; 22-a first conduit; 23-a first condenser; 24-a first reflux drum; 25-a first reflux pump; 26-a second conduit; 27-a second condenser; 28-a second reflux drum; 29-a second reflux pump; 30-a first trap; 31-an exhaust gas treatment device; 32-a second trap; 33-a first control valve; 34-a second control valve; 35-monomer recovery unit; 36-vacuum means; 37-a first preheater; 38-stirring device.

Detailed Description

The invention will be further described with reference to examples of embodiments shown in the drawings.

Directional phrases used in connection with the present invention, such as "inner," "outer," "top," "bottom," "center," "upper," "lower," etc., are intended to refer only to the manner in which the appended drawings are referred to. Accordingly, the directional terminology is used for purposes of illustration and understanding and is in no way limiting.

As shown in fig. 1, the apparatus for acrylonitrile-styrene polymerization according to the present invention comprises: a first-stage reactor 1, a second-stage reactor 2, a first-stage devolatilizer 3, a second-stage devolatilizer 4, a first mixer 5 and a second mixer 6. Wherein, the first discharge gate of first order reactor 1 bottom passes through the pan feeding mouth of first order reactor 1 top of first forced return line 7 connection to connect the pan feeding mouth in first order reactor 1 middle part through second forced return line 8, can increase the dwell time of the interior material of first order reactor 1, and make the axial of material and radial mix more even. The first forced return pipeline 7 is connected with the raw material supply pipeline 9 and is provided with the first mixer 5, so that a product in the first forced return pipeline 7, unreacted raw materials and raw materials in the raw material supply pipeline 9 are mixed and then enter the primary reactor 1, and the mixing uniformity of the materials entering the primary reactor 1 can be improved. The second discharge hole at the bottom of the primary reactor 1 is connected with the feeding hole at the top of the secondary reactor 2 through a first discharge pipeline 10, so that the retention time of materials in the secondary reactor 2 can be prolonged. The first discharge port at the bottom of the secondary reactor 2 is connected with the feeding port at the top of the secondary reactor 2 through a third forced return pipeline 11 and is connected with the feeding port at the middle part of the secondary reactor 2 through a fourth forced return pipeline 12, so that the retention time of materials in the secondary reactor 2 can be prolonged, and the axial and radial mixing of the materials is more uniform. The third forced return pipeline 11 is connected with the first discharging pipeline 10 and is provided with the second mixer 6, so that the product in the third forced return pipeline 11, the unreacted raw material and the product in the first discharging pipeline 10 are mixed with the unreacted raw material and then enter the secondary reactor 2, and the mixing uniformity of the materials entering the secondary reactor 2 can be improved. A second discharge hole at the bottom of the secondary reactor 2 is connected with a feeding hole of the primary devolatilization device 3 through a second discharge pipeline 13. The discharge hole at the bottom of the first-stage devolatilization device 3 is connected with the feeding hole of the second-stage devolatilization device 4 through a third discharge pipeline 14. The discharge hole at the bottom of the secondary devolatilization device 4 is connected with a fourth discharge pipeline 15 and used for outputting products. During the use, the first reactor 1 forces the ejection of compact backward flow to the first reactor 1 through first forced backflow pipeline 7 and second forced backflow pipeline 8, the second reactor 2 forces the ejection of compact backward flow to the second reactor 2 through third forced backflow pipeline 11 and fourth forced backflow pipeline 12 in, can make the reaction system mix more evenly, dwell time increases, thereby can improve the conversion rate of acrylonitrile-styrene polymerization, utilize the first grade of one-level devolatilization ware 3 to remove most acrylonitrile, thereby reduce the time of acrylonitrile in the reaction system, and utilize the second grade of second grade devolatilization ware 4 to remove styrene, toluene and a small amount of acrylonitrile, thereby reduce the content of impurity, and then can obtain high-quality acrylonitrile-styrene polymer product, simultaneously can reduce the energy consumption, and good economic nature.

In a specific embodiment, the first discharge port at the bottom of the primary reactor 1 is connected with the first forced reflux pipeline 7 and the second forced reflux pipeline 8 through the first forced reflux pump 16, and the first forced reflux pump 16 is used for pressurizing and forced reflux, so that the structure is simple and the use is convenient. The second discharge gate of first order reactor 1 bottom is connected with first ejection of compact pipeline 10 through first discharge pump 17, utilizes the ejection of compact of first discharge pump 17 pressurization, simple structure, convenient to use. The first discharge port at the bottom of the secondary reactor 2 is connected with the third forced reflux pipeline 11 and the fourth forced reflux pipeline 12 through the second forced reflux pump 18, and the second forced reflux pump 18 is used for pressurizing and forced reflux, so that the structure is simple and the use is convenient. The second discharge hole at the bottom of the secondary reactor 2 is connected with the second discharge pipeline 13 through a second discharge pump 19, and the second discharge pump 19 is used for pressurizing and discharging, so that the structure is simple and the use is convenient. The discharge gate of ware 3 bottom is taken off to one-level is connected with third ejection of compact pipeline 14 through third discharge pump 20, utilizes the ejection of compact of third discharge pump 20 pressurization, simple structure, convenient to use. The discharge gate of 4 bottoms of ware is waved in the second grade passes through fourth discharge pump 21 and is connected with fourth discharge pipeline 15, utilizes the ejection of compact of fourth discharge pump 21 pressurization, simple structure, convenient to use. The first forced reflux pump 16 and the first discharge pump 17 may be provided in combination or separately, as required. Preferably, the first forced reflux pump 16 and the first discharge pump 17 are provided separately.

In a specific embodiment, the top of the first-stage reactor 1 is connected to the inlet end of a first condenser 23 through a first pipeline 22, the outlet end of the first condenser 23 is connected to the inlet end of a first reflux drum 24, and the outlet end of the first reflux drum 24 is connected to the first-stage reactor 1 through a first reflux pump 25, so that the temperature in the first-stage reactor 1 can be maintained at a specific value.

In a specific embodiment, the angle between the axis of the first condenser 23 and the horizontal line is 5 to 90 degrees, which can prevent residues in the first condenser 23 from causing monomer polymerization and coking.

In a specific embodiment, the top of the secondary reactor 2 is connected to the inlet of a second condenser 27 through a second pipe 26, the outlet of the second condenser 27 is connected to the inlet of a second reflux drum 28, and the outlet of the second reflux drum 28 is connected to the secondary reactor 2 through a second reflux pump 29, so that the temperature inside the secondary reactor 2 can be maintained at a specific value.

In a specific embodiment, the angle between the axis of the second condenser 27 and the horizontal line is 5 to 90 degrees, which can prevent residues in the second condenser 27 from causing monomer polymerization coking.

In one particular embodiment, first conduit 22 is coupled to exhaust treatment device 31 via a first trap 30, which enables non-condensable gasses within first conduit 22 to enter exhaust treatment device 31 and prevent the accumulation of non-condensable gasses within first conduit 22. The second pipeline 26 is connected with the exhaust gas treatment device 31 through the second steam trap 32, so that the non-condensable gas in the second pipeline 26 can enter the exhaust gas treatment device 31, and the non-condensable gas is prevented from accumulating in the second pipeline 26.

In one particular embodiment, a first control valve 33 is provided in the line connecting first trap 30 to exhaust treatment device 31, and when an increase in pressure is detected in first line 22, first control valve 33 is opened to vent the non-condensable gasses into exhaust treatment device 31. A second control valve 34 is provided on a pipe connecting the second trap 32 and the exhaust gas treatment device 31, and when an increase in pressure in the second pipe 26 is detected, the second control valve 34 is opened to discharge the non-condensable gas into the exhaust gas treatment device 31.

In a specific embodiment, the primary devolatilizer 3 and the secondary devolatilizer 4 are both connected to a vacuum device 36 through a monomer recovery device 35, so that the primary devolatilizer 3 and the secondary devolatilizer 4 can be devolatilized under a vacuum negative pressure environment, respectively, and the devolatilized monomers can enter the monomer recovery device 35, respectively. Specifically, most of the acrylonitrile can be removed by the first-stage devolatilization of the first-stage devolatilizer 3, so that the time of the acrylonitrile in a system can be reduced, and the yellow index of a product can be effectively reduced. The second-stage devolatilization of the second-stage devolatilizer 4 can remove styrene, toluene and a small amount of acrylonitrile, thereby reducing the content of impurities and facilitating the obtainment of high-quality acrylonitrile-styrene polymer products. The monomer recovery device 35 is used for recovering the monomers generated by devolatilization of the first-stage devolatilizer 3 and the monomers generated by devolatilization of the second-stage devolatilizer 4 under the vacuum environment provided by the vacuum device 36, and recovering the monomers from the condensed liquid in the vacuum device 36 so as to recycle the monomers.

In a specific embodiment, the monomer recovery unit 35 is connected to the raw material supply line 9, so that the monomer recovered by the monomer recovery unit 35 can be mixed with the raw material in the raw material supply line 9 and the material in the first forced reflux line 7 via the first mixer 5 and then enter the first-stage reactor 1.

In a specific embodiment, the vacuum device 36 is connected to the exhaust gas treatment device 31, so that the exhaust gas generated by the vacuum device 36 can enter the exhaust gas treatment device 31 to prevent environmental pollution.

In a specific embodiment, a first preheater 37 is disposed at the top of the secondary devolatilizer 4, and the third discharging pipeline 14 is connected to the feeding port at the top of the secondary devolatilizer 4 through the first preheater 37, so that the material in the third discharging pipeline 14 can be heated and then enter the secondary devolatilizer 4, thereby facilitating the removal of styrene, toluene and a small amount of acrylonitrile.

In a specific embodiment, a second preheater is disposed on primary devolatilizer 3, and second discharge line 13 is connected to the feed port of primary devolatilizer 3 through the second preheater. When in use, the first-stage devolatilization device 3 usually adopts the process conditions of low pressure (1-50 kPa) and low temperature (100-180 ℃) to remove most of acrylonitrile, and the operation can effectively reduce the yellow index of the product. However, if the ambient temperature is low and the pipeline from the secondary reactor 2 to the primary devolatilizer 3 is long (the reaction liquid mixture has more heat transfer with the environment, which causes the temperature of the reaction liquid mixture to be low and cannot effectively remove the monomers), the temperature compensation can be performed by using the second preheater, so as to ensure the temperature of the material in the second discharge pipeline 13 entering the primary devolatilizer 3.

In a specific embodiment, the stirring devices 38 are disposed in the primary reactor 1 and the secondary reactor 2, so as to improve the mixing uniformity of the reaction systems in the primary reactor 1 and the secondary reactor 2. The stirring device 38 includes a radial flow stirrer and an axial flow stirrer, or a mixed stirrer including a radial flow stirring portion and an axial flow stirring portion, which can realize a combination of radial flow stirring and axial flow stirring, so that the horizontal direction and the vertical direction of the reaction system in the first-stage reactor 1 and the second-stage reactor 2 are uniformly mixed, and the conversion rate can be further improved.

In one particular embodiment, the paddle pattern of the stirring device 38 comprises: the multi-layer four-blade flat blade, the multi-layer four-blade inclined blade, the multi-layer two-blade flat blade, the multi-layer two-blade inclined blade, the multi-layer three-blade turbine blade, the anchor blade, the ribbon blade, the screw blade or the combination of the above stirring type blades, and the multi-layer four-blade flat blade, the multi-layer four-blade inclined blade, the multi-layer three-blade turbine blade, the anchor type blade, the ribbon blade, the screw type blade or the combination of the above stirring type blades has simple structure and convenient use.

In a specific embodiment, when the stirring device 38 includes a radial flow stirrer and an axial flow stirrer, the radial flow stirrer and the axial flow stirrer are arranged at an interval from top to bottom, so that a stirring manner combining the radial flow stirring and the axial flow stirring can be conveniently realized, and the reaction system can be uniformly mixed.

In a specific embodiment, the feeding direction of the first forced circulation line 7 at the feeding port at the top of the first reactor 1 is vertical downward, and the feeding direction is the same as the flow direction of the stream formed by the stirring device 38 in the first reactor 1 at the feeding port at the top of the first reactor 1 after feeding, so that the flow of the stream in the first reactor 1 vertically downward can be increased through the first forced circulation line 7, and the axial mixing of the reaction system in the first reactor 1 is better. I.e. by further pushing the stirring effect in the primary reactor 1 by means of forced reflux.

In a specific embodiment, the feeding direction of the third forced circulation line 11 at the feeding port at the top of the secondary reactor 2 is vertical downward, and the feeding direction is the same as the flow direction of the stream formed by the stirring device 38 in the secondary reactor 2 at the feeding port at the top of the secondary reactor 2 after feeding, so that the flow of the stream in the secondary reactor 2 vertically downward can be increased through the third forced circulation line 11, and the axial mixing of the reaction system in the secondary reactor 2 is better. I.e. by further pushing the stirring effect in the secondary reactor 2 by means of forced reflux.

In a specific embodiment, the feeding position of the second forced reflux line 8 is below the liquid level of the reaction liquid and the product in the first-stage reactor 1, and the feeding direction of the second forced reflux line 8 is horizontal, so that the mixing degree of the reaction system in the first-stage reactor 1 in the horizontal direction can be increased, and the radial mixing of the reaction system in the first-stage reactor 1 is better. I.e. by further pushing the stirring effect in the primary reactor 1 by means of forced reflux.

In a specific embodiment, the height of the feeding position of the second forced reflux pipeline 8 from the lower end socket of the first-stage reactor 1 is one tenth to four fifths of the height of the liquid level in the first-stage reactor 1, so that the mixing degree of the reaction system in the first-stage reactor 1 in the horizontal direction can be further increased.

In a preferred embodiment, the feeding position of the second forced reflux line 8 is separated from the lower head of the first-stage reactor 1 by a height of two fifths to seven tenths of the height of the liquid level in the first-stage reactor 1, so that the mixing degree of the reaction system in the first-stage reactor 1 in the horizontal direction can be further increased.

In a specific embodiment, the feeding position of the fourth forced return line 12 is below the liquid level of the reaction liquid and the product in the secondary reactor 2, and the feeding direction of the fourth forced return line 12 is horizontal, so that the mixing degree of the reaction system in the secondary reactor 2 in the horizontal direction can be increased, and the radial mixing of the reaction system in the secondary reactor 2 is better. I.e. by further pushing the stirring effect in the secondary reactor 2 by means of forced reflux.

In a specific embodiment, the height of the feeding position of the fourth forced return pipeline 12 from the lower end socket of the secondary reactor 2 is one tenth to four fifths of the height of the liquid level in the secondary reactor 2, so that the mixing degree of the reaction system in the secondary reactor 2 in the horizontal direction can be further increased.

In a preferred embodiment, the feeding position of the fourth forced return line 12 is separated from the bottom head of the secondary reactor 2 by a height of two fifths to seven tenths of the height of the liquid level in the secondary reactor 2, so that the mixing degree of the reaction system in the secondary reactor 2 in the horizontal direction can be further increased.

In a specific embodiment, the number of the second forced return lines 8 and/or the fourth forced return lines 12 is multiple, which can further increase the mixing degree of the reaction system in the first stage reactor 1 and/or the second stage reactor 2 in the horizontal direction.

In a specific embodiment, the number of the second forced reflux lines 8 is even, for example, the number of the second forced reflux lines 8 is 2, 4, 6, 8 or 10, and the reaction system in the first-stage reactor 1 can be better mixed by the symmetrical arrangement. The number of the fourth forced return lines 12 is even, for example, the number of the fourth forced return lines 12 is 2, 4, 6, 8 or 10, which can make the reaction system in the secondary reactor 2 mix better by the symmetrical arrangement.

In a specific embodiment, the outside of the first-stage reactor 1, the outside of the second-stage reactor 2, the outside of the first devolatilizer 3 and the outside of the second devolatilizer 4 are all sleeved with jacket parts, heat tracing media are arranged in the jacket parts, and a jacket heat tracing mode is adopted, so that the heat transfer efficiency can be improved, the heat tracing effect is good, the structure is simple, and the use is convenient.

In a specific embodiment, the heat tracing medium comprises steam or hot oil, and the heat tracing effect is good and economical.

In one particular embodiment, the feedstock comprises: styrene, acrylonitrile, solvent and molecular weight regulator, and can improve the polymerization effect of acrylonitrile-styrene. Wherein the feeding mass ratio of the styrene to the acrylonitrile is 7:3, the polymerization reaction of acrylonitrile-styrene has good effect.

In a particular embodiment, the feedstock comprises styrene and acrylonitrile. Wherein, the mass fraction of the styrene is 50-90 percent, the mass fraction of the acrylonitrile is 10-50 percent, and the high-quality acrylonitrile-styrene polymer product can be conveniently obtained. Preferably, the mass fraction of styrene is 60% to 80%. The mass fraction of the acrylonitrile is 20-40%, and the high-quality acrylonitrile-styrene polymer product can be further conveniently obtained.

In a particular embodiment, the solvent comprises: toluene, butylbenzene, benzene and/or xylene and all isomers of xylene can enhance the acrylonitrile-styrene polymerization effect. Preferably, the solvent is toluene, so that the reaction temperature can be reduced, the energy consumption can be saved, and the yellow index of the product can be reduced.

In a specific embodiment, the mass fraction of the toluene in the raw materials is 1-10%, the energy-saving effect is good, and the effect of reducing the yellow index of the product is good.

In a specific embodiment, the temperature in the primary reactor 1 and the temperature in the secondary reactor 2 are both 100-180 ℃, which can improve the polymerization effect of acrylonitrile-styrene.

In a preferred embodiment, the temperature in the first-stage reactor 1 and the temperature in the second-stage reactor 2 are both 130-170 ℃, so that the polymerization effect of acrylonitrile-styrene can be further improved.

In a specific embodiment, the temperature in the first-stage devolatilizer 3 is 100-180 ℃, the pressure in the first-stage devolatilizer 3 is 1-50 kPa, most of acrylonitrile can be removed by adopting the process conditions of low pressure and low temperature, and the yellow index of the product is effectively reduced. As shown in FIG. 2, the reaction curve was 150 degrees Celsius based on the reaction system, and the total conversion was 78% by weight (mass) percent ratio). The ordinate in figure 2 is the mass fraction of acrylonitrile after the primary devolatilization and the abscissa is the temperature of the material entering the primary devolatilization (in c), the different curves representing different pressures (PRE, in bar). It can be obtained from the sensitivity result curve of fig. 2 that when the pressure is low and the temperature is 130 degrees centigrade or higher, the mass fraction of acrylonitrile has not changed much, and the difficulty obtained by comprehensively considering the low pressure, the pressure in the primary devolatilizer 3 is set to 5 kpa during the operation, the temperature in the primary devolatilizer 3 is set to 150 degrees centigrade, and at this time, the temperature in the primary devolatilizer 3 is the same as the temperature of the reaction system, and it should be noted that the environmental temperature is low, and when the pipeline from the secondary reactor 2 to the primary devolatilizer 3 is long, the second preheater may be added for temperature compensation.

In a preferred embodiment, the temperature in the primary devolatilizer 3 is 130 to 170 ℃, the pressure in the primary devolatilizer 3 is 5 to 39 kPa, the removal effect of acrylonitrile is good, and the effect of reducing the yellowness index of the product is good. It is further preferred that the pressure within the primary devolatilizer 3 be 5 kPa.

In a specific embodiment, the operating temperature of the secondary devolatilizer 4 is 200 to 300 ℃, and the pressure inside the secondary devolatilizer 4 is 1 to 50 kpa, which can effectively remove the remaining styrene, toluene and a small amount of acrylonitrile impurities.

In a preferred embodiment, the temperature in the secondary devolatilizer 4 is 220-280 ℃, the pressure in the secondary devolatilizer 4 is 5-39 kPa, and the removal effect of impurities such as styrene, toluene and a small amount of acrylonitrile is good. Further preferably, the pressure within secondary devolatilizer 4 is 5 kPa.

When the device is used, one material in the product in the first-stage reactor 1 and one part of the incompletely reacted raw materials is forcedly refluxed through the first forced reflux pipeline 7, is mixed with the raw materials through the first mixer 5 during the overcharging of the forced reflux and then enters the first-stage reactor 1, the other material in one part is forcedly refluxed into the first-stage reactor 1 through the second forced reflux pipeline 8, and the other part of the product and the incompletely reacted raw materials enter the second-stage reactor 2 through the first discharge pipeline 10. Products in the secondary reactor 2 and one material in one part of the incompletely reacted raw materials are forcedly refluxed through a third forced reflux pipeline 11, and are mixed with the materials in the first discharging pipeline 10 through a second mixer 6 during the overcharging of the forced reflux and then enter the secondary reactor 2, the other material in one part is forcedly refluxed into the secondary reactor 2 through a fourth forced reflux pipeline 12, and the other part of products and the incompletely reacted raw materials enter a primary devolatilization device 3 through a second discharging pipeline 13 to be subjected to primary devolatilization. The discharge in the primary devolatilization device 3 enters the secondary devolatilization device 4 through a third discharge pipeline 14 for secondary devolatilization. The monomer generated by the two-stage devolatilization and the condensate in the vacuum device 36 both enter the monomer recovery device 35, the monomer is recovered by the monomer recovery device 35, and the recovered monomer is conveyed to the raw material supply pipeline 9 for reuse. The acrylonitrile-styrene polymerization product after the two-stage devolatilization is output through a fourth discharge pipeline 15.

One specific example is listed below:

the raw materials comprise styrene, acrylonitrile, toluene and a molecular weight regulator, wherein the feeding ratio of the styrene to the acrylonitrile is 7:3 (mass ratio) (feed mass ratio) and the reaction is initiated thermally. The temperature of the reaction system was 150 ℃. The pressure in the first-stage devolatilizer 3 was 5 kPa, and the feed temperature was 150 ℃. The pressure of the secondary devolatilizer 4 is 5 kpa, and the material flowing out of the primary devolatilizer 3 is heated to 250 ℃ by a first preheater 37. The conversion rate after the two-stage reaction in the first-stage reactor 1 and the second-stage reactor 2 was able to reach 78% by weight, after the two-stage devolatilization in the first-stage devolatilizer 3 and the second-stage devolatilizer 4, in which the mass fractions of styrene and acrylonitrile were close to 0, and the yellowness index of the acrylonitrile-styrene polymerization product was less than 5.

The protective scope of the present invention is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present invention by those skilled in the art without departing from the scope and spirit of the present invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (28)

1. An apparatus for acrylonitrile-styrene polymerization, comprising: a primary reactor (1), a secondary reactor (2), a primary devolatilization device (3), a secondary devolatilization device (4), a first mixer (5) and a second mixer (6); wherein the content of the first and second substances,

a first discharge hole at the bottom of the primary reactor (1) is connected with a feed inlet at the top of the primary reactor (1) through a first forced reflux pipeline (7), and is connected with a feed inlet in the middle of the primary reactor (1) through a second forced reflux pipeline (8); the first forced return line (7) is connected with a raw material supply line (9) and is provided with the first mixer (5); a second discharge hole at the bottom of the primary reactor (1) is connected with a feeding hole at the top of the secondary reactor (2) through a first discharge pipeline (10); a first discharge hole at the bottom of the secondary reactor (2) is connected with a feed inlet at the top of the secondary reactor (2) through a third forced reflux pipeline (11) and is connected with a feed inlet in the middle of the secondary reactor (2) through a fourth forced reflux pipeline (12); the third forced return pipeline (11) is connected with the first discharge pipeline (10) and is provided with the second mixer (6); a second discharge hole at the bottom of the secondary reactor (2) is connected with a feed inlet of the primary devolatilizer (3) through a second discharge pipeline (13); a discharge hole at the bottom of the primary devolatilization device (3) is connected with a feeding hole of the secondary devolatilization device (4) through a third discharge pipeline (14); and a discharge hole at the bottom of the secondary devolatilization device (4) is connected with a fourth discharge pipeline (15) and is used for outputting products.

2. The apparatus according to claim 1, wherein the first discharge port of the bottom of the first stage reactor (1) is connected to the first forced reflux pipeline (7) and the second forced reflux pipeline (8) through a first forced reflux pump (16), the second discharge port of the bottom of the first stage reactor (1) is connected to the first discharge pipeline (10) through a first discharge pump (17), the first discharge port of the bottom of the second stage reactor (2) is connected to the third forced reflux pipeline (11) and the fourth forced reflux pipeline (12) through a second forced reflux pump (18), the second discharge port of the bottom of the second stage reactor (2) is connected to the second discharge pipeline (13) through a second discharge pump (19), the discharge port of the bottom of the first stage devolatilizer (3) is connected to the third discharge pipeline (14) through a third discharge pump (20), and the discharge port of the bottom of the second stage devolatilizer (4) is connected to the fourth discharge pipeline (15) through a fourth discharge pump (21).

3. An apparatus for polymerization of acrylonitrile-styrene according to claim 1, characterized in that the top of the first reactor (1) is connected to the inlet of a first condenser (23) by a first pipe (22), the outlet of the first condenser (23) is connected to the inlet of a first reflux drum (24), the outlet of the first reflux drum (24) is connected to the first reactor (1) by a first reflux pump (25), the top of the second reactor (2) is connected to the inlet of a second condenser (27) by a second pipe (26), the outlet of the second condenser (27) is connected to the inlet of a second reflux drum (28), and the outlet of the second reflux drum (28) is connected to the second reactor (2) by a second reflux pump (29).

4. An apparatus for polymerization of acrylonitrile-styrene according to claim 3, characterized in that the axis of the first condenser (23) is at an angle of 5-90 degrees to the horizontal and the axis of the second condenser (27) is at an angle of 5-90 degrees to the horizontal.

5. Apparatus for polymerization of acrylonitrile-styrene according to claim 3, characterized in that the first line (22) is connected to an exhaust gas treatment device (31) through a first trap (30) and the second line (26) is connected to the exhaust gas treatment device (31) through a second trap (32).

6. The apparatus for polymerization of acrylonitrile-styrene according to claim 5, wherein a first control valve (33) is provided on a line connecting the first trap (30) and the waste gas treatment device (31), and a second control valve (34) is provided on a line connecting the second trap (32) and the waste gas treatment device (31).

7. The apparatus for polymerization of acrylonitrile-styrene according to claim 5, wherein the primary devolatilizer (3) and the secondary devolatilizer (4) are connected to a vacuum device (36) through a monomer recovery device (35), and the monomer recovery device (35) is used for recovering the monomer devolatilized by the primary devolatilizer (3) and the monomer devolatilized by the secondary devolatilizer (4) under the vacuum environment provided by the vacuum device (36) and recovering the monomer from the condensed liquid in the vacuum device (36).

8. The apparatus for polymerization of acrylonitrile-styrene according to claim 7, characterized in that the monomer recovery unit (35) is connected to the raw material supply line (9).

9. The apparatus for polymerization of acrylonitrile-styrene according to claim 7, characterized in that the vacuum device (36) is connected to the waste gas treatment device (31).

10. The apparatus for polymerization of acrylonitrile-styrene according to claim 1, wherein the top of the secondary devolatilizer (4) is provided with a first preheater (37), the third discharge line (14) is connected with the feed inlet of the secondary devolatilizer (4) through the first preheater (37), the top of the primary devolatilizer (3) is provided with a second preheater, and the second discharge line (13) is connected with the feed inlet of the primary devolatilizer (3) through the second preheater.

11. The apparatus for polymerization of acrylonitrile-styrene according to claim 1, wherein stirring means (38) are provided in both the primary reactor (1) and the secondary reactor (2), the stirring means (38) comprising a radial flow stirrer and an axial flow stirrer, or a hybrid stirrer comprising a radial flow stirring section and an axial flow stirring section.

12. Apparatus for the polymerization of acrylonitrile-styrene according to claim 11, characterized in that the blade type of the stirring device (38) comprises: the multi-layer four-blade flat blade, the multi-layer four-blade inclined blade, the multi-layer two-blade flat blade, the multi-layer two-blade inclined blade, the multi-layer three-blade turbine blade, the anchor blade, the ribbon blade, the screw blade or the combination of the above stirring type blades.

13. Apparatus for the polymerization of acrylonitrile-styrene according to claim 11, wherein the stirring device (38) comprises the radial flow stirrer and the axial flow stirrer, and the radial flow stirrer and the axial flow stirrer are arranged at an upper and lower interval.

14. The apparatus for polymerization of acrylonitrile-styrene according to claim 11, wherein the feeding direction of the first forced return line (7) at the feeding port at the top of the primary reactor (1) is vertical downward, and the feeding direction is the same as the flowing direction of the stream formed by the stirring device (38) in the primary reactor (1) at the feeding port at the top of the primary reactor (1), the feeding direction of the third forced return line (11) at the feeding port at the top of the secondary reactor (2) is vertical downward, and the feeding direction is the same as the flowing direction of the stream formed by the stirring device (38) in the secondary reactor (2) at the feeding port at the top of the secondary reactor (2).

15. The apparatus for polymerization of acrylonitrile-styrene according to claim 1, wherein the feeding position of the second forced reflux line (8) is below the liquid level of the reaction liquid and the product in the first stage reactor (1), the feeding direction of the second forced reflux line (8) is horizontal, the feeding position of the fourth forced reflux line (12) is below the liquid level of the reaction liquid and the product in the second stage reactor (2), and the feeding direction of the fourth forced reflux line (12) is horizontal.

16. The apparatus for polymerization of acrylonitrile-styrene according to claim 15, wherein the feeding position of the second forced return line (8) is at a height of one tenth to four fifths of the height of the liquid level in the first reactor (1) from the bottom head of the first reactor (1), and the feeding position of the fourth forced return line (12) is at a height of one tenth to four fifths of the height of the liquid level in the second reactor (2) from the bottom head of the second reactor (2).

17. The apparatus for polymerization of acrylonitrile-styrene according to claim 16, wherein the feeding position of the second forced reflux line (8) is located at a height from the bottom head of the first reactor (1) ranging from two fifths to seven tenths of the height of the liquid level in the first reactor (1), and the feeding position of the fourth forced reflux line (12) is located at a height from the bottom head of the second reactor (2) ranging from two fifths to seven tenths of the height of the liquid level in the second reactor (2).

18. Apparatus for the polymerization of acrylonitrile-styrene according to claim 1, characterized in that the number of said second forced return line (8) and/or said fourth forced return line (12) is multiple.

19. Apparatus for the polymerization of acrylonitrile-styrene according to claim 18, characterized in that said second forced return lines (8) are even numbered and said fourth forced return lines (12) are even numbered.

20. The apparatus for acrylonitrile-styrene polymerization according to claim 1, wherein a jacket portion is sleeved on the outside of the primary reactor (1), the outside of the secondary reactor (2), the outside of the first devolatilizer (3) and the outside of the second devolatilizer (4), and a heat tracing medium is disposed in the jacket portion.

21. The apparatus for polymerization of acrylonitrile-styrene of claim 20, wherein the heat tracing medium comprises steam or hot oil.

22. The apparatus for acrylonitrile-styrene polymerization according to claim 1, wherein the raw materials comprise: styrene, acrylonitrile, solvent and molecular weight regulator.

23. The apparatus for polymerization of acrylonitrile-styrene of claim 22, wherein the solvent comprises: toluene, butylbenzene, benzene and/or xylene and all isomers of xylene.

24. The apparatus for polymerization of acrylonitrile-styrene of claim 23, wherein the solvent is toluene.

25. The apparatus for polymerization of acrylonitrile-styrene according to claim 1, wherein the temperature in the primary reactor (1) and the temperature in the secondary reactor (2) are both between 100 and 180 ℃.

26. The apparatus for polymerization of acrylonitrile-styrene according to claim 25, wherein the temperature in the primary reactor (1) and the temperature in the secondary reactor (2) are both 130-170 ℃.

27. The apparatus for polymerization of acrylonitrile-styrene according to claim 1, wherein the temperature inside the primary devolatilizer (3) is 100-180 degrees celsius, the pressure inside the primary devolatilizer (3) is 1-50 kpa, the operating temperature of the secondary devolatilizer (4) is 200-300 degrees celsius, and the pressure inside the secondary devolatilizer (4) is 1-50 kpa.

28. An apparatus for polymerization of acrylonitrile-styrene according to claim 27, wherein the temperature inside the primary devolatilizer (3) is 130-170 ℃, the pressure inside the primary devolatilizer (3) is 5-39 kpa, the temperature inside the secondary devolatilizer (4) is 220-280 ℃, and the pressure inside the secondary devolatilizer (4) is 5-39 kpa.

Images