A method and device for devolatilization of a high molecular polymer

Abstract

This invention discloses a method and apparatus for devolatilization of polymers. The devolatilization method divides the devolatilizer into first, second, and third devolatilization zones. Steam is introduced into the jacket and rotor shaft of the devolatilizer to heat the devolatilization zones. During the devolatilization process, the temperature of each devolatilization zone is strictly controlled. By obtaining the unit devolatilization time, the devolatilization temperature for the next unit devolatilization time is dynamically adjusted. The resulting high-viscosity melt is then crushed under hot medium conditions and undergoes deep devolatilization to obtain the final product. This method controls energy consumption during the devolatilization process by strictly regulating the temperature of each devolatilization zone based on the changes in the physicochemical properties of the material during the devolatilization process. The apparatus provided by this invention, through the setting of an independent closed heating system, not only effectively isolates the polymer from contact with the heating medium but also achieves distributed and precise temperature control, completely solving the generation of waste liquid and waste gas, and achieving the technical goal of highly efficient and waste-free devolatilization while significantly reducing energy consumption.

Description

Technical Field

[0001] This invention relates to a polymer devolatilization method, specifically a method and apparatus for devolatilization of high molecular weight polymers, belonging to the field of high molecular weight polymer devolatilization technology. Background Technology

[0002] Currently, the main technology for devolatilization of polymers is the water-wash coagulation devolatilization method. The main process involves adding the polymer solution to a coagulation vessel, introducing superheated steam to heat the third medium (water) to a certain temperature, and then using the hot water to further heat the polymer solution to remove the reacting monomers and solvents, thus achieving the purpose of water-wash coagulation devolatilization. However, this method has several drawbacks: it requires heating a low-thermal-conductivity liquid medium (water) as the heat source for heating the polymer solution; the process is lengthy, resulting in high energy consumption and production costs; it requires a large land area and numerous equipment, leading to high construction investment; it generates a large amount of waste liquid and waste gas, resulting in high environmental protection costs; and it is not suitable for the production of certain products, thus affecting the industrialization process of new products. Therefore, developing a new devolatilization method and apparatus is essential to effectively solve these problems. Summary of the Invention

[0003] To address the problems existing in the prior art, the first objective of this invention is to provide a method for devolatilization of polymers. This method controls energy consumption during the devolatilization process by strictly regulating the temperature of each devolatilization zone based on the changes in the physicochemical properties of the material during the devolatilization process. It employs a jacketed heating system and a rotor shaft heating system with steam as the heat source, avoiding direct contact between the heating medium and the polymer. This not only achieves precise temperature control but also completely eliminates the generation of waste liquid and waste gas, thereby achieving the technical objective of highly efficient and waste-free devolatilization while significantly reducing energy consumption.

[0004] The second objective of this invention is to provide a polymer devolatilization device that achieves dynamic temperature control during the devolatilization process by detecting changes in the physicochemical properties of the polymer in different zones. By setting up an independent closed heating system, it not only effectively isolates the polymer from the heating medium but also achieves distributed and precise temperature control. This device has the advantages of simple structure, stable performance, and low cost, and is suitable for large-scale industrial applications.

[0005] To achieve the above technical objectives, the present invention provides a polymer devolatilization device, including a devolatilizer (1), a deep devolatilization device, and a gas treatment device; a rotor shaft (2) is provided on the central axis of the long shaft of the devolatilizer, and a rotor shaft heating system is provided inside the rotor shaft for temperature control of the rotor shaft; a first devolatilization zone (4), a second devolatilization zone (5), and a third devolatilization zone (6) are arranged sequentially inside the devolatilizer along the rotor shaft entry direction, and a jacketed heating system is provided between the first, second, and third devolatilization zones and the shell of the devolatilizer, and a volatilization channel (3) connected to the gas treatment device is opened on each devolatilization zone; a polymer inlet (11) is opened on the first devolatilization zone of the devolatilizer, and a polymer outlet (12) connected to the deep devolatilization device is opened on the third devolatilization zone; a nitrogen inlet (13) is also opened on the first devolatilization zone for replacing the air atmosphere inside the devolatilizer.

[0006] As a preferred embodiment, the gas processing device includes a gas-liquid separator (71), a first condenser (72), a pre-pump buffer tank (73), a vacuum pump (74), a second condenser (75), and a liquid storage device (8) connected in sequence; the liquid phase component in the pre-pump buffer tank (73) directly enters the liquid storage device through a pipeline, and the gas phase component enters the second condenser through the vacuum pump.

[0007] As a preferred embodiment, the liquid storage device is also provided with an exhaust port that is directly connected to the first condenser.

[0008] As a preferred embodiment, the deep devolatilization device includes a colloidal transfer pump (15), a crushing and separation device (9), a gas-liquid stirring tank (10), and a transfer pump (14) connected in sequence.

[0009] As a preferred embodiment, after the polymer discharge port of the devolatilizer discharges the material, it enters the crushing and separation device for crushing via a colloid conveying pump. The gas-liquid stirring tank is used to perform deep devolatilization on the crushed polymer particles, and discharge the volatiles and polymer.

[0010] As a preferred embodiment, the delivery pump is also directly connected to the crushing and separating device for multiple devolatilization processes.

[0011] As a preferred embodiment, the gas-liquid stirring vessel is also provided with an air inlet, which is connected to the rotor shaft heating system and the jacket heating system.

[0012] The present invention also provides a method for devolatilization of polymers, implemented by any one of the above-described apparatus, comprising the following steps:

[0013] S1. Steam is introduced into the jacket of the degassing machine and the rotor shaft (2) to preheat the degassing machine (1);

[0014] S2. The polymer is fed into the first devolatilization zone of the devolatilization machine through the polymer inlet (11), and then undergoes devolatilization treatment in the second and third devolatilization zones in sequence;

[0015] S3 obtains the initial viscosity value of the polymer entering the devolatilizer, the viscosity value of the first devolatilized product and the viscosity value of the second devolatilized product, and the devolatilized mass (wt). When the initial viscosity value is >0 and the viscosity value of the first devolatilized product is =0, step S4 is started. When the viscosity value of the first devolatilized product is >0, step S5 is started.

[0016] S4. Based on the initial viscosity value, the viscosity value of the first devolatilization product and the viscosity value of the second devolatilization product and the devolatilization mass (wt), set the rotational speed of the rotor shaft (2) and the devolatilization temperatures of the first devolatilization zone (4), the second devolatilization zone (5) and the third devolatilization zone (6);

[0017] S5. Obtain the mass of polymer transported per unit time. Take the time from entering the devolatilizer (1) to exiting the devolatilizer (1) as the unit devolatilization time. Obtain the initial viscosity value, the viscosity value of the first devolatilization product, the viscosity value of the second devolatilization product, and the devolatilization mass (wt) within the unit devolatilization time. Adjust the devolatilization temperature of the first devolatilization zone (4), the second devolatilization zone (5), and the third devolatilization zone (6) within the next unit devolatilization time.

[0018] S6. The high molecular polymer after devolatilization by the devolatilizer (1) is transported to the crushing and separation device (9) for crushing and separation;

[0019] S7. Perform deep devolatilization on the polymer particles, obtain the initial viscosity value and the deep devolatilization mass per unit time (wt), and adjust the devolatilization temperature and rotation speed of the gas-liquid stirred tank;

[0020] S8. Output polymer particles after deep devolatilization;

[0021] The devolatilization mass is the mass of volatiles (wt) released from the polymer, and the devolatilization mass per unit time depth (wt) is the mass of volatiles (wt) released from the polymer in the gas-liquid stirred tank per unit time.

[0022] The first devolatilization product is the polymer after it has undergone devolatilization treatment in the first devolatilization zone;

[0023] The second devolatilization product is the polymer after it has undergone devolatilization treatment in the second devolatilization zone.

[0024] As a preferred embodiment, the temperatures of the first, second, and third devolatilization zones in S4 are obtained through the following method:

[0025] S4-1. Temperature of the first devolatilization zone: Set the temperature of the first devolatilization zone and the rotor shaft speed according to the initial viscosity value;

[0026] S4-2. Temperature of the second and third devolatilization zones: Obtain the viscosity difference between the product of the previous devolatilization zone and the polymer of the previous two devolatilization zones, and set the temperature of the current devolatilization zone.

[0027] As a preferred embodiment, the temperature range of the first, second, and third devolatilization zones is one to five levels, namely: level one temperature is 80~100℃, level two temperature is 100~120℃, level three temperature is 120~140℃, level four temperature is 140~160℃, and level five temperature is 160~190℃.

[0028] As a preferred embodiment, the rotor shaft speed is either a high speed or a low speed, with the high speed being 68-200 rpm and the low speed being 16-68 rpm.

[0029] As a preferred embodiment, the temperature of the first devolatilization zone is: when the initial viscosity value is less than or equal to the first viscosity threshold, the devolatilization temperature of the first devolatilization zone (4) is set to a first-level temperature and the rotor shaft speed is a high speed; otherwise, the devolatilization temperature of the first devolatilization zone (4) is set to a second-level temperature and the rotor shaft speed is a low speed.

[0030] As a preferred embodiment, the temperature of the second devolatilization zone is as follows: when the difference between the viscosity value of the first devolatilization product and the initial viscosity value is less than or equal to the first viscosity difference, if the first devolatilization mass (wt) is less than or equal to the first mass (wt) threshold, the devolatilization temperature of the second devolatilization zone (5) is set to a fourth temperature; if the first mass threshold is less than or equal to the first devolatilization mass (wt) and less than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization zone (5) is set to a third temperature; if the first devolatilization mass (wt) is greater than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization zone (5) is set to a second temperature.

[0031] When the first viscosity difference < the difference between the viscosity of the first devolatilized product and the initial viscosity value ≤ the second viscosity difference, if the first devolatilized mass (wt) ≤ the first mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the fifth temperature level; if the first mass threshold < the first devolatilized mass (wt) ≤ the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the fourth temperature level; if the first devolatilized mass (wt) > the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the third temperature level.

[0032] When the difference between the viscosity of the first devolatilized product and the initial viscosity is greater than the second viscosity difference, if the first devolatilized mass (wt) is less than or equal to the first mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the sixth temperature level; if the first mass threshold is less than or equal to the first devolatilized mass (wt) and less than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the fifth temperature level; if the first devolatilized mass (wt) is greater than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the fourth temperature level.

[0033] As a preferred embodiment, the first viscosity difference refers to the difference between the viscosity values ​​of the products in the second devolatilization region and the first devolatilization region, and the second viscosity difference refers to the difference between the viscosity values ​​of the products in the third devolatilization region and the first devolatilization region; the first mass wt% threshold refers to the difference between the mass wt% of the products in the second devolatilization region and the first devolatilization region, and the second mass wt% threshold refers to the difference between the mass wt% of the products in the third devolatilization region and the second devolatilization region.

[0034] In this invention, the initial viscosity value is the viscosity of the polymer when it enters the devolatilization machine; the first devolatilization product viscosity value is the polymer viscosity value when the polymer passes through the first devolatilization zone and first obtains the first devolatilization product, about to enter the second devolatilization zone; the second devolatilization product viscosity value is the polymer viscosity value when the polymer passes through the second devolatilization zone and obtains the second devolatilization product, about to enter the third devolatilization zone; the first devolatilization mass is the mass of volatiles removed when the first devolatilization product is first obtained, which is the actual value achieved; the second devolatilization mass is the mass of volatiles removed when the second devolatilization product is first obtained, which is the actual value achieved; the first mass threshold and the second mass threshold are instrument settings that can be adjusted according to actual working conditions; the first viscosity difference and the second viscosity difference can be set according to the actual polymer composition to be devolatilized, the initial viscosity value, and the solute concentration at the time of discharge and the target solute concentration at the time of discharge. Under common working conditions, the first viscosity difference can be set to 2000 mPa•s; the second viscosity difference can be set to 3000 mPa•s.

[0035] As a preferred embodiment, the temperature of the third devolatilization zone is set as follows: when the difference between the viscosity value of the second devolatilization product and the viscosity value of the first devolatilization product is less than or equal to the first viscosity difference, the devolatilization temperature of the third devolatilization zone is set by the difference between the viscosity value of the second devolatilization product and the initial viscosity value and the second devolatilization mass.

[0036] When the difference between the viscosity of the second devolatilized product and the viscosity of the first devolatilized product is greater than the first viscosity difference, if the second devolatilized mass (wt) is greater than or equal to the third mass threshold, the devolatilization temperature of the third devolatilization region (6) is set to a first temperature; if the second devolatilized mass (wt) is less than the third mass threshold, the devolatilization temperature of the third devolatilization region is set by the difference between the viscosity of the second devolatilized product and the initial viscosity and the second devolatilized mass.

[0037] As a preferred embodiment, the process of setting the devolatilization temperature of the third devolatilization zone by the difference between the viscosity value of the second devolatilization product and the initial viscosity value and the second devolatilization mass (wt) is as follows:

[0038] When the difference between the viscosity of the second devolatilized product and the initial viscosity is greater than or equal to the third viscosity difference, if the second devolatilized mass (wt) is greater than or equal to the third mass threshold, the devolatilization temperature of the third devolatilization region is set to the second temperature; if the second devolatilized mass (wt) is less than the third mass threshold, the third devolatilization region is calculated according to the devolatilization temperature formula.

[0039] When the second viscosity difference is less than the difference between the viscosity of the second devoured product and the initial viscosity and less than the third viscosity difference, if the second devoured mass (wt) is greater than or equal to the third mass threshold, the devouring temperature of the third devouring region (6) is set to a first-level temperature; if the second devoured mass (wt) is less than the third mass threshold, it is calculated according to the devouring temperature formula.

[0040] When the difference between the viscosity of the second devolatilized product and the initial viscosity is less than the second viscosity difference, if the second devolatilized mass (wt) is greater than or equal to the third mass threshold, the devolatilization temperature of the third devolatilization region (6) is set to a first-level temperature; if the second devolatilized mass (wt) is less than the third mass threshold, it is calculated according to the devolatilization temperature formula.

[0041] As a preferred embodiment, the devolatilization temperature formula is: ;

[0042] in, The devolatilization temperature of the third devolatilization zone. This refers to the devolatilization temperature in the second devolatilization zone. The total mass of the polymer to be devolatilized; For the first devolatilization quality; This is the second devolatilization quality.

[0043] As a preferred embodiment, the temperature adjustment of the first, second, and third devolatilization zones in S5 is achieved through the following method:

[0044] S5-1. The formula for calculating the unit devolatilization time of polymer transported per unit time from entering the devolatilizer (1) to exiting the devolatilizer (1) is: t = ( ) / ;

[0045] Where t is the unit volatilization time. The volume of polymer delivered per unit time. The cross-sectional area of ​​the devolatilization unit. The propulsion speed of the rotor shaft, denoted as , and k as , which is the volume coefficient of the devourer.

[0046] S5-2. Obtain the initial viscosity value, the viscosity value of the first devolatilized product, the viscosity value of the second devolatilized product, and the devolatilized mass (wt) n times within a unit devolatilization time. Calculate the average initial viscosity, the average viscosity of the first devolatilized product, the average viscosity of the second devolatilized product, and the average devolatilized mass (wt).

[0047] S5-3. Obtain the difference between the average viscosity of the first devolatilized product and the initial average viscosity, the difference between the average viscosity of the second devolatilized product and the average viscosity of the first devolatilized product, and the average devolatilized mass (wt) within the current unit devolatilization time; when the average devolatilized mass (wt) = the first target devolatilized mass (wt), maintain the temperature set in each region in S4; when the average devolatilized mass (wt) < the first target devolatilized mass (wt), calculate the temperature of each devolatilization region using the devolatilization temperature formula per unit time;

[0048] The formula for the devolatilization temperature per unit time is: ;

[0049] in The primary target is devoured mass (wt). The average devolatilization mass (wt) This represents the desorption temperature of the desorption zone within the current unit desorption time. The de-volatilization temperature of the de-volatilization zone in the next unit of de-volatilization time, when When the calculated value is greater than the highest devolatilization temperature that the polymer can withstand, then Calculate the highest devolatilization temperature.

[0050] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0051] 1) The devolatilization method provided by this invention controls energy consumption during the devolatilization process by strictly regulating the temperature of each devolatilization zone based on the changes in the physicochemical properties of the material during the devolatilization process. It adopts a jacket heating system and a rotor shaft heating system with steam as the heat source, which avoids direct contact between the heating medium and the polymer. This not only achieves precise temperature control, but also completely solves the problem of waste liquid and waste gas generation, thereby achieving the technical goal of high-efficiency and waste-free devolatilization while significantly reducing energy consumption.

[0052] 2) The devolatilization device provided by the present invention achieves dynamic temperature control of the devolatilization process by detecting changes in the physicochemical properties of the polymer in different zones. By setting up an independent closed heating system, it not only effectively isolates the polymer from the heating medium, but also achieves distributed and precise temperature control. The device has the advantages of simple structure, stable performance and low cost, and is suitable for large-scale industrial applications.

[0053] 3) The technical solution provided by this invention uses steam to heat the jacket and rotor shaft of the devolatilizer, and then exchanges heat with the polymer. This replaces the need to heat a liquid medium (water) with low thermal conductivity as a heat source for heating the adhesive, avoiding the problems of high energy consumption and the generation of large amounts of waste liquid and waste gas. Based on the monitoring of the viscosity change and devolatilization mass (wt) data of the polymer, the jacket temperature and rotor shaft speed of the devolatilizer in the first, second, and third devolatilization zones are dynamically adjusted to improve the devolatilization efficiency. This method and device have advantages such as high devolatilization efficiency, low waste liquid and waste gas volume, high operational flexibility, short process route, and low investment cost. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the process for the polymer devolatilization method provided by the present invention;

[0055] Figure 2 This is a schematic diagram of the polymer devolatilization device provided by the present invention;

[0056] Figure 2 In the diagram, 1-devolatilizer, 2-rotor shaft, 3-evaporation channel, 4-first devolatilization zone, 5-second devolatilization zone, 6-third devolatilization zone, 71-gas-liquid separator, 72-first condenser, 73-pump buffer tank, 74-vacuum pump, 75-second condenser, 8-liquid storage device, 9-crushing and separating device, 10-gas-liquid stirring vessel, 11-polymer inlet, 12-polymer outlet, 13-nitrogen inlet, 14-transfer pump, 15-colloidal transfer pump. Detailed Implementation

[0057] The specific implementation schemes of the present invention will be described in detail and clearly below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0058] The embodiments provided by this invention are all implemented through the following devolatilization device: The polymer devolatilization device includes a devolatilizer 1, a deep devolatilization device, and a gas treatment device; a rotor shaft 2 is arranged on the central axis of the long shaft of the devolatilizer, and a rotor shaft heating system is provided inside the rotor shaft for temperature control; a first devolatilization zone 4, a second devolatilization zone 5, and a third devolatilization zone 6 are arranged sequentially inside the devolatilizer along the rotor shaft entry direction, and a jacketed heating system is provided between the first, second, and third devolatilization zones and the devolatilizer housing; each devolatilization zone has a volatilization channel 3 connected to the gas treatment device; the devolatilizer has a polymer inlet 11 in the first devolatilization zone and a polymer outlet 12 connected to the deep devolatilization device in the third devolatilization zone; a nitrogen inlet 13 is also provided in the first devolatilization zone for replacing the air atmosphere inside the devolatilizer.

[0059] The rotor shaft heating system, jacket heating system, and deep devolatilization heating system are connected to an external steam device to form a circulating heating system. The steam temperature can be changed by controlling the external steam heating device. Steam temperature controllers can also be installed at the inlet and outlet of the rotor shaft heating system and jacket heating system to change the steam temperature.

[0060] The gas processing device includes a gas-liquid separator 71, a first condenser 72, a pre-pump buffer tank 73, a vacuum pump 74, and a second condenser 75 connected in sequence. The devolatilization machines 1 corresponding to the first devolatilization zone 4, the second devolatilization zone 5, and the third devolatilization zone 6 are equipped with evaporation channels 3, all connected to the gas-liquid separator 71. The outlet of the second condenser 75 is connected to a liquid storage device 8. The volatiles volatilized from the first devolatilization zone 4, the second devolatilization zone 5, and the third devolatilization zone 6 enter the gas-liquid separator 71 through the evaporation channels 3, separating the trace amounts of liquid carried in the volatiles. The gaseous volatiles pass through the first condenser 72 and then enter the pre-pump buffer tank 73, where the liquid volatiles are collected. Inside, the liquid volatiles in the pre-pump buffer tank 73 enter the storage device 8 through the outlet for storage, while the gaseous volatiles enter the second condenser 75 through the vacuum pump 74 for condensation. The condensed liquid volatiles then enter the storage device 8 for storage. During this process, some non-gaseous volatiles are carried into the storage device 8. This portion of gaseous volatiles enters the first condenser 72 through the exhaust port of the storage device 8 for condensation again. The gas-liquid separator 71, the first condenser 72, the pre-pump buffer tank 73, the vacuum pump 74, the second condenser 75, and the storage device 8 form a circulating volatiles recovery system. The devolatilization mass (wt) can also be obtained by monitoring the change in mass (wt) of the storage device 8 per unit time.

[0061] The deep devolatilization device includes a crushing and separating device 9 and a gas-liquid stirred tank 10 connected to the crushing and separating device 9. The crushing and separating device 9 is used to crush the high-viscosity polymer discharged from the material outlet 12 of the devolatilizer 1. The gas-liquid stirred tank 10 is used to perform deep devolatilization on the crushed polymer particles. The deep devolatilization heating system is used to heat the gas-liquid stirred tank 10. A high-viscosity adhesive delivery pump 15 is also provided between the crushing and separating device 9 and the material outlet 12 of the devolatilizer 1 to ensure that the high-viscosity adhesive can be smoothly delivered to the crushing and separating device 9.

[0062] The deep devolatilization device also includes a pump 14 for supplying a hot liquid medium to the crushing and separating device 9. In this scheme, the hot liquid medium is water, and the hot liquid medium originates from outside this scheme. The colloidal water after being crushed by the crushing and separating device 9 is transported to the gas-liquid stirring tank 10 for deep devolatilization, and the deeply devolatilized colloidal water is pumped into the next process.

[0063] Example 1

[0064] This embodiment describes the devolatilization of the polymer elastomers SIS and SBS, using cyclohexane as the de-devouring medium. The method and apparatus used are as follows: Figure 1 and Figure 2 As shown. The heat medium used for devolatilization is steam at 0.8–1.0 MPa and hot water at 90–98 °C. Cyclohexane has a heat capacity of 1.68 kJ / (kg·°C), an enthalpy of vaporization of 4.27 × 10² kJ / kg, and an azeotropic point with water of 68.95 °C. The hot water is used for deep devolatilization, and its flow rate is 12 m³ / kg. 3 / h.

[0065] The specific divergence process is as follows:

[0066] 1) Calculate the devolatilization mass of each section.

[0067] SBS adhesive solution enters from the polymer inlet 11 of the devolatilizer 1 at a feed rate of 300 kg / h. The initial SBS adhesive solution solid content (wt%) is 16%. The devolatilization target value for the first stage is an SBS adhesive solution solid content (wt%) of 35%. The target value for the second stage deep devolatilization is a cyclohexane content in the SBS particles ≤ 1000 ppm (wt%). The pure SBS polymer flow rate is 48 kg / h, and the cyclohexane solvent flow rate is:

[0068] 300kg / h - 48kg / h = 252kg / h;

[0069] The amount of cyclohexane solvent contained in SBS adhesive with a solid content of 35% is:

[0070] (48kg / h) / (35%)-48kg⁄h=89.143kg / h;

[0071] The amount of solvent removed is: 252 kg / h - 89.143 kg / h = 162.857 kg / h;

[0072] Therefore, the first target devolatilization mass is 162.857 kg / h, which is the volatile mass (wt) removed by devolatilizer 1 per hour, with 64.63% of cyclohexane removed; the second devolatilization target is to remove cyclohexane from SBS adhesive with a solid content of 35% in the deep devolatilization stage, which is to remove 89 kg / h of cyclohexane, which is the volatile mass that should be removed by gas-liquid stirred tank 10 per hour.

[0073] 2) Start the device to perform devolatilization

[0074] The data calculated in step 1) shows that the SIS feed rate is 300 kg / h, the initial SBS solution solid content (wt%) is 10%, and the temperature is 65℃. The SBS solution enters the machine body through the material inlet 11 of the devolatilizer 1, and then passes through the shell and internal components of the three-section zone of the devolatilizer 1. The shell temperature of the devolatilizer 1 is 110-150℃, and the internal temperature of the devolatilizer 1 is 150-178℃. The cyclohexane in the SBS solution is removed from the three devolatilization ports of the devolatilizer 1 and enters the recovery device. The mass of cyclohexane removed is 214.19 kg / h, and the removal rate is 79.33%. At this time, the solid content of the SBS solution reaches 32%-35% (wt%), and the steam consumption is 1.013 t / t. The SBS solution after devolatilization is discharged from the material outlet 12 of the devolatilizer 1 and enters the crushing and separation device 9. Mechanical crushing and separation are performed under hot water conditions of 90℃ to 98℃. The crushed and separated SBS solution becomes rubber particles and enters the gas-liquid stirred tank 10 for deep devolatilization. The released cyclohexane enters the recovery device, and the rubber particle water enters the next process. At this point, the cyclohexane content in the rubber particles is 850-1000 ppm (wt%), the particle size is Ø3-Ø5 mm, and the length is 5-9 mm.

[0075] As can be seen from the above data, the device and method provided by this invention for deep devolatilization of polymers, based on the three-stage devolatilization zone setting of the devolatilizer, achieves a cyclohexane removal rate of 79.33%, which is much higher than the calculated 64.63% removal rate of the devolatilizer. This provides a good precursor for subsequent deep devolatilization. Furthermore, after deep devolatilization, the cyclohexane content in the resulting particles is only 850-1000 ppm, with a cyclohexane removal rate ≥99.9%, and it has good continuous performance.

Claims

1. A method for devolatilization of a polymer, characterized in that, include: S1. Steam is introduced into the jacket of the degassing machine and the rotor shaft (2) to preheat the degassing machine (1); S2. The polymer is fed into the first devolatilization zone of the devolatilization machine through the polymer inlet (11), and then undergoes devolatilization treatment in the second and third devolatilization zones in sequence; S3 obtains the initial viscosity value of the polymer entering the devolatilizer, the viscosity value of the first devolatilized product and the viscosity value of the second devolatilized product, and the devolatilized mass (wt). When the initial viscosity value is >0 and the viscosity value of the first devolatilized product is =0, step S4 is started. When the viscosity value of the first devolatilized product is >0, step S5 is started. S4. Based on the initial viscosity value, the viscosity value of the first devolatilization product and the viscosity value of the second devolatilization product and the devolatilization mass (wt), set the rotational speed of the rotor shaft (2) and the devolatilization temperatures of the first devolatilization zone (4), the second devolatilization zone (5) and the third devolatilization zone (6); S5. Obtain the mass of polymer transported per unit time. Take the time from entering the devolatilizer (1) to exiting the devolatilizer (1) as the unit devolatilization time. Obtain the initial viscosity value, the viscosity value of the first devolatilization product, the viscosity value of the second devolatilization product, and the devolatilization mass (wt) within the unit devolatilization time. Adjust the devolatilization temperature of the first devolatilization zone (4), the second devolatilization zone (5), and the third devolatilization zone (6) within the next unit devolatilization time. S6. The high molecular polymer after devolatilization by the devolatilizer (1) is transported to the crushing and separation device (9) for crushing and separation; S7. Perform deep devolatilization on the polymer particles, obtain the initial viscosity value and the deep devolatilization mass per unit time (wt), and adjust the devolatilization temperature and rotation speed of the gas-liquid stirred tank; S8. Output polymer particles after deep devolatilization; The devolatilization mass is the mass of volatiles (wt) released from the polymer, and the devolatilization mass per unit time depth (wt) is the mass of volatiles (wt) released from the polymer in the gas-liquid stirred tank per unit time. The first devolatilization product is the polymer after it has undergone devolatilization treatment in the first devolatilization zone; The second devolatilization product is the polymer after it has undergone devolatilization treatment in the second devolatilization zone; The apparatus for implementing the above method includes a devolatilizer (1), a deep devolatilization device, and a gas treatment device; a rotor shaft (2) is provided on the central axis of the long shaft of the devolatilizer, and a rotor shaft heating system is provided inside the rotor shaft for temperature control of the rotor shaft; a first devolatilization zone (4), a second devolatilization zone (5), and a third devolatilization zone (6) are arranged sequentially inside the devolatilizer along the rotor shaft entry direction, and a jacketed heating system is provided between the first, second, and third devolatilization zones and the devolatilizer housing, and a volatilization channel (3) connected to the gas treatment device is opened on each devolatilization zone; a polymer inlet (11) is opened on the first devolatilization zone of the devolatilizer, and a polymer outlet (12) connected to the deep devolatilization device is opened on the third devolatilization zone; a nitrogen inlet (13) is also opened on the first devolatilization zone for replacing the air atmosphere inside the devolatilizer.

2. The method for devolatilization of a polymer according to claim 1, characterized in that: The gas processing device includes a gas-liquid separator (71), a first condenser (72), a pre-pump buffer tank (73), a vacuum pump (74), a second condenser (75), and a liquid storage device (8) connected in sequence. The liquid phase component in the pre-pump buffer tank (73) enters the liquid storage device directly through a pipeline, and the gas phase component enters the second condenser through the vacuum pump. The liquid storage device is also provided with an exhaust port that is directly connected to the first condenser.

3. The method for devolatilization of a polymer according to claim 1, characterized in that: The deep devolatilization device includes a colloid conveying pump (15), a crushing and separating device (9), a gas-liquid stirring tank (10), and a conveying pump (14) connected in sequence. After the polymer discharge outlet of the devolatilizer discharges the material, it enters the crushing and separating device for crushing via the colloid conveying pump. The gas-liquid stirring tank is used to perform deep devolatilization on the crushed polymer particles and discharge the volatiles and polymer. The conveying pump is also directly connected to the crushing and separating device for multiple devolatilization operations. The gas-liquid stirring tank is also provided with an air inlet and is connected to the rotor shaft heating system and the jacket heating system.

4. The method for devolatilization of a polymer according to claim 1, characterized in that: The temperatures of the first, second, and third devolatilization zones in S4 are obtained through the following method: S4-1. Temperature of the first devolatilization zone: Set the temperature of the first devolatilization zone and the rotor shaft speed according to the initial viscosity value; S4-2. Temperature of the second and third devolatilization zones: Obtain the viscosity difference between the product of the previous devolatilization zone and the polymer of the previous two devolatilization zones, and set the temperature of the current devolatilization zone; The temperature range of the first, second and third devolatilization zones is from one to five levels, namely: Level 1 temperature is 80~100℃, Level 2 temperature is 100~120℃, Level 3 temperature is 120~140℃, Level 4 temperature is 140~160℃, and Level 5 temperature is 160~190℃. The rotor shaft speed is either high or low, with high speed being 68-200 rpm and low speed being 16-68 rpm.

5. The method for devolatilization of a polymer according to claim 1, characterized in that: The first devolatilization zone temperature is: when the initial viscosity value is less than or equal to the first viscosity threshold, the devolatilization temperature of the first devolatilization zone (4) is set to the first temperature level and the rotor shaft speed is high speed; otherwise, the devolatilization temperature of the first devolatilization zone (4) is set to the second temperature level and the rotor shaft speed is low speed.

6. The method for devolatilization of a polymer according to claim 1, characterized in that: The temperature of the second devolatilization zone is as follows: when the difference between the viscosity value of the first devolatilization product and the initial viscosity value is less than or equal to the first viscosity difference, if the first devolatilization mass (wt) is less than or equal to the first mass (wt) threshold, the devolatilization temperature of the second devolatilization zone (5) is set to the fourth temperature level; if the first mass threshold is less than or equal to the first devolatilization mass (wt) and less than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization zone (5) is set to the third temperature level; if the first devolatilization mass (wt) is greater than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization zone (5) is set to the second temperature level. When the first viscosity difference < the difference between the viscosity of the first devolatilized product and the initial viscosity value ≤ the second viscosity difference, if the first devolatilized mass (wt) ≤ the first mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the fifth temperature level; if the first mass threshold < the first devolatilized mass (wt) ≤ the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the fourth temperature level; if the first devolatilized mass (wt) > the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to the third temperature level. When the difference between the viscosity of the first devolatilized product and the initial viscosity is greater than the second viscosity difference, if the first devolatilized mass (wt) is less than or equal to the first mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to a temperature of level six; if the first mass threshold is less than or equal to the first devolatilized mass (wt) and less than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to a temperature of level five; if the first devolatilized mass (wt) is greater than or equal to the second mass threshold, the devolatilization temperature of the second devolatilization region (5) is set to a temperature of level four. The first viscosity difference refers to the difference between the viscosity value of the product in the second devolatilization region and the viscosity value of the product in the first devolatilization region; the second viscosity difference refers to the difference between the viscosity value of the product in the third devolatilization region and the viscosity value of the product in the first devolatilization region; the first mass wt% threshold refers to the difference between the mass wt% of the product in the second devolatilization region and the mass wt% of the product in the first devolatilization region; the second mass wt% threshold refers to the difference between the mass wt% of the product in the third devolatilization region and the mass wt% of the product in the second devolatilization region.

7. The method for devolatilization of a polymer according to claim 1, characterized in that: The temperature of the third devolatilization zone is set as follows: when the difference between the viscosity value of the second devolatilization product and the viscosity value of the first devolatilization product is less than or equal to the first viscosity difference, the devolatilization temperature of the third devolatilization zone is set by the difference between the viscosity value of the second devolatilization product and the initial viscosity value and the second devolatilization mass. When the difference between the viscosity of the second devolatilized product and the viscosity of the first devolatilized product is greater than the first viscosity difference, if the second devolatilized mass (wt) is greater than or equal to the third mass threshold, the devolatilization temperature of the third devolatilization region (6) is set to a first temperature; if the second devolatilized mass (wt) is less than the third mass threshold, the devolatilization temperature of the third devolatilization region is set by the difference between the viscosity of the second devolatilized product and the initial viscosity and the second devolatilized mass.

8. The method for devolatilization of a polymer according to claim 1, characterized in that: The process of setting the devolatilization temperature of the third devolatilization zone by using the difference between the viscosity value of the second devolatilization product and the initial viscosity value and the second devolatilization mass (wt) is as follows: When the difference between the viscosity of the second devolatilized product and the initial viscosity is greater than or equal to the third viscosity difference, if the second devolatilized mass (wt) is greater than or equal to the third mass threshold, the devolatilization temperature of the third devolatilization region is set to the second temperature; if the second devolatilized mass (wt) is less than the third mass threshold, the third devolatilization region is calculated according to the devolatilization temperature formula. When the second viscosity difference is less than the difference between the viscosity of the second devoured product and the initial viscosity and less than the third viscosity difference, if the second devoured mass (wt) is greater than or equal to the third mass threshold, the devouring temperature of the third devouring region (6) is set to a first-level temperature; if the second devoured mass (wt) is less than the third mass threshold, it is calculated according to the devouring temperature formula. When the difference between the viscosity of the second devolatilized product and the initial viscosity is less than the second viscosity difference, if the second devolatilized mass (wt) is greater than or equal to the third mass threshold, the devolatilization temperature of the third devolatilization region (6) is set to a first-level temperature; if the second devolatilized mass (wt) is less than the third mass threshold, it is calculated according to the devolatilization temperature formula. The formula for the devolatilization temperature is: ; in, The devolatilization temperature of the third devolatilization zone. This refers to the devolatilization temperature in the second devolatilization zone. The total mass of the polymer to be devolatilized; For the first devolatilization quality; This is the second devolatilization quality.

9. The method for devolatilization of a polymer according to claim 1, characterized in that: The temperatures of the first, second, and third devolatilization zones in S5 are obtained through the following method: S5-1. The formula for calculating the unit devolatilization time of polymer transported per unit time from entering the devolatilizer (1) to exiting the devolatilizer (1) is: t = ( ) / ; Where t is the unit volatilization time. The volume of polymer delivered per unit time. The cross-sectional area of ​​the devolatilization unit. The propulsion speed of the rotor shaft, is the length of the devourer, and k is the volume coefficient of the devourer; S5-2. Obtain the initial viscosity value, the viscosity value of the first devolatilized product, the viscosity value of the second devolatilized product, and the devolatilized mass (wt) n times within a unit devolatilization time. Calculate the average initial viscosity, the average viscosity of the first devolatilized product, the average viscosity of the second devolatilized product, and the average devolatilized mass (wt). S5-3. Obtain the difference between the average viscosity of the first devolatilized product and the initial average viscosity, the difference between the average viscosity of the second devolatilized product and the average viscosity of the first devolatilized product, and the average devolatilized mass (wt) within the current unit devolatilization time; when the average devolatilized mass (wt) = the first target devolatilized mass (wt), maintain the temperature set in each region in S4; when the average devolatilized mass (wt) < the first target devolatilized mass (wt), calculate the temperature of each devolatilization region using the devolatilization temperature formula per unit time; The formula for the devolatilization temperature per unit time is: ; in The primary target is devoured mass (wt). The average devolatilization mass (wt) This represents the desorption temperature of the desorption zone within the current unit desorption time. The de-volatilization temperature of the de-volatilization zone in the next unit of de-volatilization time, when When the calculated value is greater than the highest devolatilization temperature that the polymer can withstand, then Calculate the highest devolatilization temperature.

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