A devolatilization granulation device for styrene-based polymers

Abstract

The application discloses a devolatilization and granulation device for a styrene polymer, which comprises a primary devolatilizer and a secondary devolatilizer; a feeding end of the primary devolatilizer is connected with a first pipeline for receiving material to be devolatilized; a discharging end of the primary devolatilizer is connected with the secondary devolatilizer through a second pipeline; the primary devolatilizer is connected with a first vacuum device through a third pipeline and is connected with a fourth pipeline for receiving nitrogen; a first flow meter is arranged on the first pipeline, a first control valve is arranged on the third pipeline, and a second control valve is arranged on the fourth pipeline; the first flow meter is connected with the first control valve and the second control valve through a pressure indication controller and forms a flow pressure regulating loop, which is used for adjusting the pressure in the primary devolatilizer according to the flow of the material to be devolatilized, and then determining the devolatilization ratio of the primary devolatilizer according to the pressure in the primary devolatilizer, so that the feeding amount of the material entering the secondary devolatilizer and the components of the material are kept stable. The styrene polymer with high productivity and low residual monomer can be obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chemical devices, and particularly relates to a devolatilization and granulation device for styrene polymers. BACKGROUND

[0002] Styrene polymers include styrene-acrylonitrile copolymer (SAN resin or AS resin) and polystyrene (PS). Styrene polymers are white translucent to transparent thermoplastic resins, have good dimensional stability and processing performance, can be shaped by injection, extrusion or modification, and the shaped products can be used in daily necessities, household appliances, automobiles and stationery fields, and are widely used in national production and life.

[0003] The mainstream production process of styrene polymers is a solvent modified continuous bulk process technology, that is, monomer raw materials are polymerized by an initiator or heat initiation in the presence of an appropriate amount of solvent. The solvent modified continuous bulk process has the advantages of short process flow and less three-waste emissions. However, the solvent modified continuous bulk process has the disadvantages that the viscosity of the post-reaction material is high, the separation of unreacted monomers and solvent from the product is difficult, and the product has high residual monomer, so the process and equipment level of the devolatilization unit are key factors affecting the product quality and capacity of the solvent modified continuous bulk polymerization device.

[0004] The styrene polymer continuous bulk process generally uses one-stage devolatilization, and the residual monomer of the polymer product is generally higher than 2000 ppm (parts per million). Although the two-stage devolatilization process can reduce the residual monomer content in the product to a certain extent, due to the lack of effective devolatilization ratio control measures in the traditional two-stage devolatilization process, when the total amount of upstream material entering the devolatilization and granulation device changes, the amount of material entering the two devolatilizers will change, and especially the second-stage devolatilizer usually operates at a higher temperature, so the change in feed load will have a more obvious impact on the residual monomer and / or color of the product. In addition, the traditional whole device capacity is generally below 15 tons / hour, which is low in efficiency. SUMMARY

[0005] The present application aims to overcome the deficiencies of the prior art, and provides a devolatilization and granulation device for styrene polymers, which can obtain high-capacity, low-residual styrene polymers.

[0006] To solve the above technical problems, the present application adopts the following technical scheme: a devolatilization granulation device for styrene polymers, comprising: a primary devolatilizer and a secondary devolatilizer; wherein the feed end of the primary devolatilizer is connected with a first pipeline for receiving material to be devolatilized; the discharge end of the primary devolatilizer is connected with the secondary devolatilizer through a second pipeline; the primary devolatilizer is connected with a first vacuum device through a third pipeline, and is connected with a fourth pipeline for receiving nitrogen; a first flow meter is arranged on the first pipeline, a first control valve is arranged on the third pipeline, and a second control valve is arranged on the fourth pipeline; the first flow meter connects the first control valve and the second control valve through a pressure indication controller and forms a flow pressure regulation loop, which is used for adjusting the pressure in the primary devolatilizer according to the flow of the material to be devolatilized, and then determining the devolatilization ratio of the primary devolatilizer according to the pressure in the primary devolatilizer, so that the feed amount and the composition of the material entering the secondary devolatilizer remain stable.

[0007] In one specific embodiment, the secondary devolatilizer is connected with a second vacuum device through a fifth pipeline, and a first preheater is arranged at the top of the secondary devolatilizer, and the second pipeline is connected with the secondary devolatilizer through the first preheater.

[0008] In one specific embodiment, the first preheater comprises a first hot medium inlet pipeline and a first hot medium outlet pipeline in communication with the first hot medium inlet pipeline, and the first hot medium in the first hot medium inlet pipeline and the first hot medium outlet pipeline is used to heat the material flowing through the first preheater and entering the secondary devolatilizer.

[0009] In one specific embodiment, a hot medium temperature adjusting valve is arranged on the first hot medium outlet pipeline near the outlet, a second flow meter is arranged on the second pipeline, the second flow meter is connected with the hot medium temperature adjusting valve through a temperature indication controller and forms a flow temperature regulation loop, which is used for adjusting the temperature of the first preheater according to the flow of the material entering the secondary devolatilizer, and then determining the operating temperature of the secondary devolatilizer.

[0010] In one specific embodiment, the temperature of the first hot medium is 20-80 degrees Celsius higher than the viscous flow state temperature of the material entering the secondary devolatilizer, and the pressure in the secondary devolatilizer is 0.5-3 kilopascals.

[0011] In one specific embodiment, a second preheater is arranged at the top of the primary devolatilizer, and the first pipeline is connected with the primary devolatilizer through the second preheater.

[0012] In one specific embodiment, the second preheater comprises a second hot medium inlet pipeline and a second hot medium outlet pipeline in communication with the second hot medium inlet pipeline, and the second hot medium in the second hot medium inlet pipeline and the second hot medium outlet pipeline is used to heat the material to be devolatilized flowing through the second preheater and entering the primary devolatilizer.

[0013] In one specific embodiment, the temperature of the second hot medium is 10-50 degrees Celsius higher than the temperature of the material to be devolatilized, and the pressure in the primary devolatilizer is 20-120 kilopascals.

[0014] In one specific embodiment, the device further comprises a plurality of pelletizers, and the bottom of the secondary devolatilizer is provided with a plurality of first conical discharge outlets, and the bottom of each first conical discharge outlet is connected to one of the pelletizers through a first discharge pump.

[0015] In one specific embodiment, the bottom discharge end of the primary devolatilizer is provided with a second conical discharge outlet, and the bottom of the second conical discharge outlet is connected to the second pipeline through a second discharge pump.

[0016] In one specific embodiment, the third pipeline is provided with a first separation tank and a first condensing device, and the first separation tank is arranged between the first condensing device and the primary devolatilizer.

[0017] In one specific embodiment, the fifth pipeline is provided with a second separation tank and a second condensing device, and the second separation tank is arranged between the second condensing device and the secondary devolatilizer.

[0018] In one specific embodiment, the first condensing device and the second condensing device are both connected to a condensate collection tank, and the condensate collection tank is connected to a recycling pipeline through a condensate recovery pump.

[0019] In one specific embodiment, the first vacuum device comprises a first vacuum pump, and the second vacuum device comprises a second vacuum pump.

[0020] Compared with the prior art, the beneficial effects of the present application are:

[0021] The present application can improve the product quality of styrene polymers, so that the residual monomer content of styrene polymer products is less than 600 ppm, the product yellow index is less than 2.0, and the hourly capacity of a single devolatilization and pelletization device is improved, so that the hourly capacity of the device is higher than 30 tons / hour, and the structure is simple, convenient to use, widely applicable, and has broad market prospects. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1A structural schematic diagram of one specific embodiment of the devolatilization and granulation device for styrene polymers of the present application is shown.

[0023] wherein, 1 - first stage devolatilizer; 2 - second stage devolatilizer; 3 - first line; 4 - second line; 5 - third line; 6 - first vacuum device; 7 - fourth line; 8 - first flow meter; 9 - first control valve; 10 - second control valve; 11 - pressure indicating controller; 12 - fifth line; 13 - second vacuum device; 14 - first preheater; 141 - first heat medium inlet line; 142 - first heat medium outlet line; 15 - heat medium temperature regulating valve; 16 - second flow meter; 17 - temperature indicating controller; 18 - second preheater; 181 - second heat medium inlet line; 182 - second heat medium outlet line; 19 - pelletizer; 20 - first conical discharge outlet; 21 - first discharge pump; 22 - second conical discharge outlet; 23 - second discharge pump; 24 - first separation tank; 25 - first condensing device; 26 - second separation tank; 27 - second condensing device; 28 - condensate collection tank; 29 - condensate recovery pump; 30 - recovery and reuse line. DETAILED DESCRIPTION

[0024] The present application is further described by the following examples with reference to the accompanying drawings.

[0025] The directional terms mentioned in the present application, such as "inner", "outer", "top", "bottom", etc., are only for reference to the accompanying drawings. Therefore, the directional terms used are for the purpose of illustration and understanding of the present application, and are not intended to limit the present application.

[0026] As Figure 1The devolatilization and granulation device for styrene polymer comprises a first devolatilizer 1 and a second devolatilizer 2. The feed end of the first devolatilizer 1 is connected with a first pipeline 3 for receiving the material to be devolatilized, and the first devolatilizer 1 can remove the solvent and monomer in the material to be devolatilized. The discharge end of the first devolatilizer 1 is connected with the second devolatilizer 2 through a second pipeline 4, and the second devolatilizer 2 can remove the remaining solvent and monomer in the material to be devolatilized. The first devolatilizer 1 is connected with a first vacuum device 6 through a third pipeline 5 and connected with a fourth pipeline 7 for receiving nitrogen, the first vacuum device 6 can vacuumize the first devolatilizer 1, and the nitrogen entering the first devolatilizer 1 can provide nitrogen sealing pressure. A first flowmeter 8 is arranged on the first pipeline 3, which can detect the flow (mass flow, feed amount) of the material to be devolatilized. A first control valve 9 is arranged on the third pipeline 5, which can realize vacuumization or stop vacuumization of the first devolatilizer 1 by opening or closing. A second control valve 10 is arranged on the fourth pipeline 7, which can realize the entry or stop of the nitrogen into the first devolatilizer 1 by opening or closing. The first flowmeter 8 is connected with the first control valve 9 and the second control valve 10 through a pressure indicating controller 11 and forms a flow-pressure regulating loop, which is used to adjust the pressure in the first devolatilizer 1 according to the flow of the material to be devolatilized, and then determine the devolatilization ratio of the first devolatilizer 1 according to the pressure in the first devolatilizer 1 (the percentage of the removed material amount to the solvent and monomer in the material to be devolatilized), so that the feed amount and the composition of the material entering the second devolatilizer 2 remain stable, the devolatilization is good, and excessive devolatilization can be avoided. In use, under the condition of devolatilization feed load change, the first devolatilizer 1 inlet flow-pressure regulating loop can automatically adjust the control pressure of the first devolatilizer 1, so as to adjust the devolatilization ratio of the first devolatilizer 1 and avoid excessive devolatilization. Specifically, the material to be devolatilized enters the first devolatilizer 1 to remove the solvent and monomer. After the first devolatilization in the first devolatilizer 1, the material to be devolatilized enters the second devolatilizer 2 to remove the remaining solvent and monomer. When the material to be devolatilized enters the first devolatilizer 1 for devolatilization, the pressure indicating controller 11 can automatically display the pressure value of the first devolatilization of the first devolatilizer 1 according to the feed amount of the material to be devolatilized on the first pipeline 3 detected by the first flowmeter 8, and adjust the opening or closing of the first control valve 9 and the opening or closing of the second control valve 10, so that the pressure value in the first devolatilizer 1 is in a stable equilibrium state. At the same time, when the flow of the material to be devolatilized changes, the pressure indicating controller 11 can automatically set the first devolatilization pressure (the pressure of the first devolatilization of the first devolatilizer 1) from one value to another value, for example, the change interval is 30 kPa to 90 kPa, according to the flow-pressure cascade control formed by the first flowmeter 8, the pressure indicating controller 11 and the first control valve 9 and the second control valve 10.For example, if the feed quantity of the material to be devolatilized changes from 36 tons to 15 tons, the pressure indicating controller 11 can automatically set the devolatilization pressure from 30 kPa to 90 kPa according to the flow-pressure cascade control. If the feed quantity of the material to be devolatilized changes from 15 tons to 36 tons, the pressure indicating controller 11 can automatically set the devolatilization pressure from 90 kPa to 30 kPa according to the flow-pressure cascade control. When the feed quantity of the material to be devolatilized is 15 tons, the devolatilization pressure is 90 kPa, and the devolatilization ratio of the primary devolatilizer 1 is 30%. When the feed quantity of the material to be devolatilized is 36 tons, the devolatilization pressure is 30 kPa, and the devolatilization ratio of the primary devolatilizer 1 is 80% (as shown in Table 1 below).

[0027] Table 1: Process parameter data of the material to be devolatilized entering the primary devolatilizer 1 and the secondary devolatilizer 2

[0028]

[0029] Therefore, the flow-pressure cascade control can increase the load of the primary devolatilization (the feed quantity of the material to be devolatilized), so that the feed quantity of the material to be devolatilized can change within a certain range (for example, 15-39 tons). When the feed quantity of the material to be devolatilized increases, the pressure indicating controller 11 can automatically adjust the pressure in the primary devolatilizer 1 according to the pressure cascade control, so that the devolatilization ratio of the primary devolatilizer 1 also increases, and the feed quantity and the composition of the material entering the secondary devolatilizer 2 remain stable. When the devolatilization pressure deviates from the stable equilibrium state, if the pressure in the primary devolatilizer 1 is too small, the pressure indicating controller 11 controls the second control valve 10 to open, and nitrogen gas enters the primary devolatilizer 1, so that the pressure in the primary devolatilizer 1 increases, and at the same time, the pressure indicating controller 11 controls the first control valve 9 to close, and stops the vacuum pumping. If the pressure in the primary devolatilizer 1 is too large, the pressure indicating controller 11 controls the first control valve 9 to open, and the first vacuum device pumps the vacuum, so that the pressure in the primary devolatilizer 1 decreases, and at the same time, the pressure indicating controller 11 controls the second control valve 10 to close, and stops the nitrogen gas filling. When the devolatilization pressure is in the stable equilibrium state, the first control valve 9 and the second control valve 10 are both closed. The pressure indicating controller 11 can automatically adjust the pressure in the primary devolatilizer 1 according to the flow of the material to be devolatilized detected by the first flow meter 8, and keep the pressure in the primary devolatilizer 1 in the stable equilibrium state, so that the stability, safety and reliability of the primary devolatilization are improved, the quantitative devolatilization effect is good, and over-devolatilization can be avoided.

[0030] In a specific embodiment, the primary devolatilization of the primary devolatilizer 1 is used to remove most of the acrylonitrile. The secondary devolatilization of the secondary devolatilizer 2 is used to remove toluene, styrene and a small amount of residual acrylonitrile.

[0031] In a specific embodiment, the secondary devolatilizer 2 is connected with the second vacuum device 13 through the fifth pipeline 12, and the second vacuum device 13 can vacuumize the secondary devolatilizer 2. The top of the secondary devolatilizer 2 is provided with the first preheater 14, and the second pipeline 4 is connected with the secondary devolatilizer 2 through the first preheater 14, and the first preheater 14 can heat the material flowing through the first preheater 14 and entering the secondary devolatilizer 2.

[0032] In a specific embodiment, the first preheater 14 comprises the first heat medium inlet pipeline 141 and the first heat medium outlet pipeline 142 in communication with the first heat medium inlet pipeline 141, and the material flowing through the first preheater 14 and entering the secondary devolatilizer 2 is heated by the first heat medium in the first heat medium inlet pipeline 141 and the first heat medium outlet pipeline 142, which has high heating efficiency, good heating effect, and simple structure and is convenient to use.

[0033] In one specific embodiment, a heat medium temperature adjusting valve 15 is arranged on the first heat medium outlet pipeline 142 near the outlet, which can adjust the temperature of the first heat medium by controlling the flow rate of the first heat medium, and then determine the temperature of the first preheater 14 according to the temperature of the first heat medium, and the position near the outlet of the first heat medium outlet pipeline 142 can improve the heating effect of the first preheater 14 by adjusting the temperature of the first heat medium after heat exchange, and prevent the inaccuracy of the temperature caused by heat loss. A second flow meter 16 is arranged on the second pipeline 4, which can detect the flow (mass flow, feed amount) of the material entering the secondary devolatilizer 2 on the second pipeline 4. The second flow meter 16 is connected with the heat medium temperature adjusting valve 15 through a temperature indicating controller 17 and forms a flow-temperature adjusting loop, which is used to adjust the temperature of the first preheater 14 according to the flow of the material entering the secondary devolatilizer 2, and then determine the operating temperature of the secondary devolatilizer 2, which can avoid the degradation of the styrene polymer in the secondary devolatilization process caused by too high temperature, so that the residual monomer content in the styrene polymer product after secondary devolatilization is less than 600 ppm, and the product yellow index is less than 2.0, while avoiding incomplete devolatilization. In use, the inlet flow-temperature adjusting loop of the secondary devolatilizer 2 can automatically adjust the operating temperature of the secondary devolatilizer 2 within a certain range, avoiding the degradation of the styrene polymer in the devolatilization process caused by too high temperature. Specifically, when the material entering the secondary devolatilizer 2 is subjected to secondary devolatilization, the temperature indicating controller 17 can automatically display the operating temperature of the secondary devolatilizer 2 according to the flow detected by the second flow meter 16, and adjust the flow rate of the first heat medium through the heat medium temperature adjusting valve 15 to make the temperature of the first preheater 14 in a stable equilibrium state, and then make the operating temperature of the secondary devolatilizer 2 in a stable equilibrium state. At the same time, when the flow of the material entering the secondary devolatilizer 2 changes, the temperature indicating controller 17 can automatically set the secondary devolatilization temperature (the operating temperature of the secondary devolatilizer 2 during secondary devolatilization) from one value to another value, for example, the change interval is 240 degrees Celsius to 310 degrees Celsius, according to the flow-temperature cascade split-range control formed by the second flow meter 16 and the heat medium temperature adjusting valve 15. As an example, if the feed amount of the material entering the secondary devolatilizer 2 changes from 26.4 tons to 13.5 tons, the temperature indicating controller 17 can automatically set the secondary devolatilization temperature from 310 degrees Celsius to 240 degrees Celsius according to the flow-temperature cascade split-range control. If the feed amount of the material entering the secondary devolatilizer 2 changes from 13.5 tons to 26.4 tons, the temperature indicating controller 17 can automatically set the secondary devolatilization temperature from 240 degrees Celsius to 310 degrees Celsius according to the flow-temperature cascade split-range control.When the feed amount of the material into the secondary devolatilizer 2 is 13.5 tons, the secondary devolatilization temperature is 240 degrees Celsius, the devolatilization ratio of the secondary devolatilizer 2 is 70%, the devolatilization ratio of the primary devolatilizer 1 is 30%, and the ratio of the devolatilization ratio of the primary devolatilizer 1 to the devolatilization ratio of the secondary devolatilizer 2 is 3:7. When the feed amount of the material into the secondary devolatilizer 2 is 26.4 tons, the secondary devolatilization temperature is 310 degrees Celsius, the devolatilization ratio of the secondary devolatilizer 2 is 20%, the devolatilization ratio of the primary devolatilizer 1 is 80%, and the ratio of the devolatilization ratio of the primary devolatilizer 1 to the devolatilization ratio of the secondary devolatilizer 2 is 8:2 (as shown in Table 1 above). Therefore, the flow temperature cascade split-range control can increase the load of the secondary devolatilization (the feed amount of the material into the secondary devolatilizer 2), so that the feed amount of the material into the secondary devolatilizer 2 can be changed within a certain range (for example, 13.5-26.4 tons), and when the feed amount of the material into the secondary devolatilizer 2 increases, the temperature cascade control of the temperature indicating controller 17 can automatically adjust the operating temperature in the secondary devolatilizer 2 to meet the heat balance requirement, so that the solvent and monomer in the material into the secondary devolatilizer 2 are completely removed, and the ratio of the devolatilization ratio of the primary devolatilizer 1 to the devolatilization ratio of the secondary devolatilizer 2 tends to increase. Moreover, when the secondary devolatilization temperature deviates from the stable balance state, if the operating temperature in the secondary devolatilizer 2 is too low, the temperature indicating controller 17 controls the heat medium temperature adjusting valve 15 to increase the flow rate to increase the first heat medium temperature, so that the temperature of the first preheater 14 increases, and then the operating temperature of the secondary devolatilizer 2 increases; if the operating temperature in the secondary devolatilizer 2 is too high, the temperature indicating controller 17 controls the heat medium temperature adjusting valve 15 to slow down the flow rate to decrease the first heat medium temperature, so that the temperature of the first preheater 14 decreases, and then the operating temperature of the secondary devolatilizer 2 decreases. When the secondary devolatilization temperature is in the stable balance state, the heat medium temperature adjusting valve 15 is in the stable balance state. The temperature indicating controller 17 can automatically adjust the temperature of the first preheater 14 according to the flow rate of the material into the secondary devolatilizer 2 detected by the second flow meter 16, so that the operating temperature of the secondary devolatilizer 2 is kept in the stable balance state, thereby improving the stability, safety and reliability of the secondary devolatilization. Moreover, the feed amount of the material into the secondary devolatilizer 2 and the components of the material remain stable, and the flow temperature adjusting loop can avoid coking of the material with too low flow rate in the first preheater 14 at high temperature, or incomplete devolatilization of the material with too high flow rate in the secondary devolatilizer 2 at high temperature, which causes too high residual monomer content in the product.

[0034] In a specific embodiment, the temperature of the first heat medium is 20-80 degrees Celsius higher than the stick flow temperature of the material into the secondary devolatilizer 2, which can improve the stability of the material into the secondary devolatilizer 2, and avoid degradation of the styrene polymer caused by too high temperature.

[0035] In a specific embodiment, the operating temperature of the secondary devolatilizer 2 is 250-310 degrees Celsius, and the pressure in the secondary devolatilizer 2 is 0.5-3 kPa, which can improve the secondary devolatilization effect, avoid excessive temperature to degrade the styrene polymer, and avoid incomplete devolatilization.

[0036] In a specific embodiment, the first heat medium includes hot oil, which has good heating effect.

[0037] In a specific embodiment, the top of the primary devolatilizer 1 is provided with a second preheater 18, and the first pipeline 3 is connected with the primary devolatilizer 1 through the second preheater 18. The second preheater 18 can heat the devolatilization material flowing through the second preheater 19 and entering the primary devolatilizer 1.

[0038] In a specific embodiment, the second preheater 18 includes a second heat medium inlet pipeline 181 and a second heat medium outlet pipeline 182 in communication with the second heat medium inlet pipeline 181, and the second heat medium in the second heat medium inlet pipeline 181 and the second heat medium outlet pipeline 182 is used to heat the devolatilization material flowing through the second preheater 18 and entering the primary devolatilizer 1. The heating efficiency is high, the heating effect is good, and the structure is simple and convenient to use.

[0039] In a specific embodiment, the temperature of the second heat medium is 10-50 degrees Celsius higher than the temperature of the devolatilization material, and the pressure in the primary devolatilizer 1 is 20-120 kPa, which can improve the primary devolatilization effect, avoid excessive temperature to degrade the styrene polymer, and avoid incomplete devolatilization.

[0040] In a specific embodiment, the second heat medium includes hot oil, which has good heating effect.

[0041] In a specific embodiment, the device further includes a plurality of granulators 19, such as 1# granulator, 2# granulator, 3# granulator, etc. The bottom of the secondary devolatilizer 2 is provided with a plurality of first conical discharge ports 20, which can facilitate the outflow of the material completing the secondary devolatilization from the secondary devolatilizer 2. The bottom of each first conical discharge port 20 is connected with one of the granulators 19 through a first discharge pump 21, which can improve the devolatilization and granulation device capacity and improve the granulation production capacity of a single set of devolatilization and granulation device. For example, the hourly production capacity of a single set of secondary devolatilization device is higher than 30 tons / hour.

[0042] In a specific embodiment, the bottom discharge end of the primary devolatilizer 1 is provided with a second conical discharge port 22, which can facilitate the outflow of the material completing the primary devolatilization from the primary devolatilizer 1. The bottom of the second conical discharge port 22 is connected with the second pipeline 4 through a second discharge pump 23, which can facilitate the material completing the primary devolatilization in the primary devolatilizer 1 to enter the second pipeline 4.

[0043] In a specific embodiment, the third pipeline 5 is provided with a first separation tank 24 and a first condensing device 25, the first separation tank 24 is arranged between the first condensing device 25 and the first devolatilizer 1, so that the gas generated by the first devolatilization can be condensed in the first condensing device 25, and the gas-liquid and / or gas-solid separation can be carried out by the first separation tank 24 before entering the first condensing device 25, so as to prevent the first condensing device 25 from being blocked.

[0044] In a specific embodiment, the fifth pipeline 12 is provided with a second separation tank 26 and a second condensing device 27, the second separation tank 26 is arranged between the second condensing device 27 and the second devolatilizer 2, so that the gas generated by the second devolatilization can be condensed in the second condensing device 27, and the gas-liquid and / or gas-solid separation can be carried out by the second separation tank 26 before entering the second condensing device 27, so as to prevent the second condensing device 27 from being blocked.

[0045] In a specific embodiment, the first condensing device 25 and the second condensing device 27 are connected to a condensate collecting tank 28, the condensate collecting tank 28 is connected to a recycling pipeline 30 through a condensate recycling pump 29, the condensed liquid in the first condensing device 25 and the second condensing device 27 enters the condensate collecting tank 28, and is pumped out through the recycling pipeline 30 by the condensate recycling pump 29 for recycling, so that the condensed liquid can be recycled, the structure is simple, the use is convenient, and the economy is good.

[0046] In a specific embodiment, the first vacuum device 6 includes a first vacuum pump, the structure is simple, and the use is convenient. The second vacuum device 13 includes a second vacuum pump, the structure is simple, and the use is convenient.

[0047] In a specific embodiment, the material to be devolatilized includes reaction products and unreacted monomers and solvents from the reactor.

[0048] The present application is used in the process of producing styrene polymer resin by using bulk polymerization process. The reaction product and unreacted monomer and solvent from the reactor are controlled by flow to enter the second preheater 18. The devolatilized material is heated and controlled by pressure to enter the first devolatilizer 1 to carry out the first devolatilization. The material after the first devolatilization is sent to the second preheater 18 by the second discharge pump 23. The temperature parameter of the second devolatilizer 2 is automatically adjusted by the second flow meter 16. The material after the first devolatilization is heated by the second preheater 18 and enters the second devolatilizer 2 to carry out the second devolatilization. The material after the second devolatilization is sent to the corresponding pelletizer 19 by the first discharge pump 21, thereby completing the two-stage devolatilization and granulation of the product. Specifically, when the feed amount of the material to be devolatilized is 15 tons, the first devolatilization pressure is 90 kPa, the devolatilization ratio of the first devolatilizer 1 is 30%, the second feed amount is 13.5 tons, the second devolatilization temperature is 240°C, and the devolatilization ratio of the second devolatilization is 70%. When the feed amount of the material to be devolatilized is 36 tons, the first devolatilization pressure is 30 kPa, the devolatilization ratio of the first devolatilizer 1 is 80%, the second feed amount is 26.4 tons, the second devolatilization temperature is 310°C, and the devolatilization ratio of the second devolatilization is 20%. Therefore, when the feed amount of the material to be devolatilized increases, the flow pressure cascade split-range adjustment can automatically adjust the pressure in the first devolatilizer 1, so that the devolatilization ratio of the first devolatilizer 1 also increases, thereby keeping the feed amount and the composition of the material entering the second devolatilizer 2 stable. Moreover, when the feed amount of the material entering the second devolatilizer 2 increases, the flow temperature cascade split-range adjustment can automatically adjust the operating temperature in the second devolatilizer 2 to meet the heat balance requirement, so that the solvent and monomer entering the second devolatilizer 2 are completely removed, and the ratio of the first devolatilization ratio to the second devolatilization ratio shows an increasing trend (as shown in Table 1 above).

[0049] The scope of the present application is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the scope and spirit of the present application. If these modifications and variations belong to the scope of the claims of the present application and their equivalent technologies, the intention of the present application also includes these modifications and variations.

Claims

1. A devolatilization granulation apparatus for styrene-based polymers, characterized in that, include: A primary devolatilizer (1) and a secondary devolatilizer (2); wherein, the feed end of the primary devolatilizer (1) is connected to a first pipeline (3) to receive the material to be devolatilized; the discharge end of the primary devolatilizer (1) is connected to the secondary devolatilizer (2) through a second pipeline (4); the primary devolatilizer (1) is connected to a first vacuum device (6) through a third pipeline (5) and to a fourth pipeline (7) to receive nitrogen; a first flow meter (8) is provided on the first pipeline (3), and a first control valve (9) is provided on the third pipeline (5). The fourth pipeline (7) is equipped with a second control valve (10). The first flow meter (8) is connected to the first control valve (9) and the second control valve (10) through a pressure indicator controller (11) to form a flow pressure regulation loop. It is used to adjust the pressure in the first-stage devourer (1) according to the flow rate of the material to be devoured, and then determine the devouring ratio of the first-stage devourer (1) according to the pressure in the first-stage devourer (1), so that the feed amount and composition of the material entering the second-stage devourer (2) remain stable.

2. The devolatilization granulation apparatus for styrene-based polymers according to claim 1, characterized in that, The secondary devolatilizer (2) is connected to the second vacuum device (13) through the fifth pipeline (12). The top of the secondary devolatilizer (2) is provided with a first preheater (14). The second pipeline (4) is connected to the secondary devolatilizer (2) through the first preheater (14).

3. The devolatilization granulation apparatus for styrene-based polymers according to claim 2, characterized in that, The first preheater (14) includes a first heat medium inlet pipe (141) and a first heat medium outlet pipe (142) connected to the first heat medium inlet pipe (141), and uses the first heat medium in the first heat medium inlet pipe (141) and the first heat medium outlet pipe (142) to heat the material flowing through the first preheater (14) and entering the secondary devolatilizer (2).

4. The devolatilization granulation apparatus for styrene-based polymers according to claim 3, characterized in that, A heat medium temperature regulating valve (15) is installed near the outlet of the first heat medium outlet pipeline (142), and a second flow meter (16) is installed on the second pipeline (4). The second flow meter (16) is connected to the heat medium temperature regulating valve (15) through a temperature indicator controller (17) to form a flow temperature regulating loop, which is used to adjust the temperature of the first preheater (14) according to the flow rate of the material entering the secondary devolatilizer (2), thereby determining the operating temperature of the secondary devolatilizer (2).

5. The devolatilization granulation apparatus for styrene-based polymers according to claim 3, characterized in that, The temperature of the first heat medium is 20 to 80 degrees Celsius higher than the viscous flow temperature of the material entering the secondary devolatilizer (2), and the pressure inside the secondary devolatilizer (2) is 0.5 to 3 kPa.

6. The devolatilization granulation apparatus for styrene-based polymers according to claim 1, characterized in that, The top of the first-stage devolatilizer (1) is provided with a second preheater (18), and the first pipeline (3) is connected to the first-stage devolatilizer (1) through the second preheater (18).

7. The devolatilization granulation apparatus for styrene-based polymers according to claim 6, characterized in that, The second preheater (18) includes a second heat medium inlet pipe (181) and a second heat medium outlet pipe (182) connected to the second heat medium inlet pipe (181), and uses the second heat medium in the second heat medium inlet pipe (181) and the second heat medium outlet pipe (182) to heat the material to be devolve that flows through the second preheater (18) and enters the first-stage devolveizer (1).

8. The devolatilization granulation apparatus for styrene-based polymers according to claim 7, characterized in that, The temperature of the second heat medium is 10 to 50 degrees Celsius higher than the temperature of the material to be devolatilized, and the pressure inside the first-stage devolatilizer (1) is 20 to 120 kPa.

9. The devolatilization granulation apparatus for styrene-based polymers according to claim 1, characterized in that, The device also includes multiple pelletizers (19), and the bottom of the secondary devolatilizer (2) is provided with multiple first conical discharge ports (20), and the bottom of each first conical discharge port (20) is connected to one of the pelletizers (19) through a first discharge pump (21).

10. The devolatilization granulation apparatus for styrene-based polymers according to claim 1, characterized in that, The bottom discharge end of the first-stage devourer (1) is provided with a second conical discharge port (22), and the bottom of the second conical discharge port (22) is connected to the second pipeline (4) through the second discharge pump (23).

11. The devolatilization granulation apparatus for styrene-based polymers according to claim 2, characterized in that, The third pipeline (5) is provided with a first separation tank (24) and a first condensation device (25), and the first separation tank (24) is located between the first condensation device (25) and the first-stage devolatilizer (1).

12. The devolatilization granulation apparatus for styrene-based polymers according to claim 11, characterized in that, The fifth pipeline (12) is provided with a second separation tank (26) and a second condensation device (27), and the second separation tank (26) is located between the second condensation device (27) and the secondary devolatilizer (2).

13. The devolatilization granulation apparatus for styrene-based polymers according to claim 12, characterized in that, The first condensing device (25) and the second condensing device (27) are both connected to a condensate collection tank (28), which is connected to a recycling pipeline (30) via a condensate recovery pump (29).

14. The devolatilization granulation apparatus for styrene-based polymers according to claim 2, characterized in that, The first vacuum device (6) includes a first vacuum pump, and the second vacuum device (13) includes a second vacuum pump.

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