Efficient devolatilization process and equipment suitable for POE (Polyolefin Elastomer) production process

Abstract

The invention relates to an efficient devolatilization process and equipment suitable for a POE (Polyolefin Elastomer) production process, the process comprises three working sections of pre-removal, primary removal and fine removal, and the pre-removal working section enables the content of a light phase to be concentrated from 70-90% to be within 20%; strip falling enhanced heat transfer is adopted in the initial removal section and the fine removal section, the light content in the initial removal section is controlled within 2.5-7%, and the light content in the fine removal section is controlled within 1%; each of the primary removal section and the fine removal section adopts a single-tube-pass strip falling evaporator and comprises a separation chamber and a strip falling type heating chamber positioned in the center of an inner cavity of the separation chamber; the strip falling type heating chamber comprises an annular strip falling heat exchange tube bundle and a heat conduction oil backflow chamber arranged in a central cavity of the annular strip falling heat exchange tube bundle, a heat conduction oil outlet is formed in the upper end of the heat conduction oil backflow chamber, and a polymer inlet is formed in the upper portion of the space between the annular strip falling heat exchange tube bundle and the heat conduction oil backflow chamber. The reaction polymer material containing a large amount of solvent can be subjected to graded devolatilization at a time, so that the light phase content index is directly not higher than 1%, and even the PPM grade requirement is met.

Description

Technical Field

[0001] The invention belongs to the field of heat transfer and chemical separation, and specifically relates to a high-efficiency devolatilization process and equipment suitable for the POE production process, which is used for the heating devolatilization process of polymer PEO. Background Art

[0002] Polyethylene oxide PEO is a thermoplastic water-soluble polymer with the advantages of good water solubility, low toxicity, easy processing and molding, and has broad application prospects. In the production process of PEO, after the devolatilization stage, the product is directly extruded and granulated. Since the content of light phase components in the product directly affects the quality grade of the product, the devolatilization stage is crucial in the entire production process. However, as a material with high viscosity and low thermal conductivity, the POE devolatilization process has always been a difficult point. It is mainly reflected in: the initial raw material liquid, that is, the product of the self-reaction polymerization stage, has a large light phase content, requiring a large heat exchange area to quickly remove the solvent; as the solvent is removed, the volume flow rate of the material decreases, and the thermal conductivity decreases rapidly, and a better enhanced heat transfer method is required at this time; when the amount of solvent in POE continues to decrease, although the heat required for solvent evaporation is very small, the heat is difficult to transfer, so a higher heat transfer driving force is required, that is, a higher heating temperature is required. However, if the temperature is too high, POE will plasticize or even coke.

[0003] At present, the process routes of POE devolatilization in my country are generally the same, mostly using front-end preheating and subsequent one-time flash evaporation using high-efficiency heat transfer equipment. The flash evaporation method results in a large difference in the removal effect between the material wall and the internal light phase, and poor uniformity.

[0004] In order to enhance the heat transfer efficiency during the POE devolatilization process, the current industrial devolatilization mostly adopts a combination of static and dynamic devolatilization processes to control the light content within 1%. However, this method relies on the dynamic devolatilization process, that is, it is necessary to use scrapers, screws and other equipment with stirring devices to forcibly disturb the high-viscosity fluid to enhance heat transfer. Although it can increase the heat transfer efficiency to a certain extent, high-viscosity PEO will still have problems such as wall adhesion and local overheating. At the same time, the use of rotary machinery for forced stirring also has the disadvantages of small heat exchange area, high manufacturing and maintenance costs, small processing volume, and difficulty in enlargement and cleaning. For high-viscosity liquids, only static devolatilization is used, even if a three-stage static devolatilization cascade is used, the light phase content in the POE product is only maintained at more than 1% (2.5%-4.8%), and the quality of the product after granulation is far from meeting the requirements of high-quality products.

[0005] To this end, developing an efficient devolatilization process suitable for POE production that can control the light phase content within 1% without combining it with dynamic devolatilization is crucial to accelerate the localization of POE production in my country. Summary of the invention

[0006] The purpose of the present invention is to provide an efficient static devolatilization process and equipment suitable for POE production, so as to solve the defects of insufficient preheating, low efficiency of the main heat transfer equipment, and high POE light phase content after devolatilization in the existing static devolatilization process. By using the process of the present invention, it is possible to achieve a one-time stepwise devolatilization of a reaction polymer material containing a large amount of solvent to directly reach a light phase content index of no more than 1%, or even to reach the PPM level requirement.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: In the first aspect, the present invention provides an efficient devolatilization process suitable for POE production, the process comprising three sections of pre-devolatilization, primary devolatilization and fine devolatilization, the pre-devolatilization section adopts an external circulation enhanced heat transfer method to concentrate the light phase content from 70-90% to less than 20%; The initial stripping stage uses stripping to enhance heat transfer, so that the light weight content is controlled within the range of 2.5-7%; The fine stripping section adopts stripping to enhance heat transfer, and the reduced pressure evaporation makes the light weight content controlled within 1%; Both the primary stripping section and the fine stripping section adopt a single-tube-pass strip-falling evaporator, including a separation chamber and a strip-falling heating chamber located in the center of the inner cavity of the separation chamber; the strip-falling heating chamber includes an annular strip-falling heat exchange tube bundle and a heat transfer oil reflux chamber arranged in the central cavity of the annular strip-falling heat exchange tube bundle, a heat transfer oil outlet is arranged at the upper end of the heat transfer oil reflux chamber, the upper end of the annular strip-falling heat exchange tube bundle is connected to the heat transfer oil inlet, and the lower part of the annular strip-falling heat exchange tube bundle is connected to the heat transfer oil reflux chamber through a lower tube compartment; a polymer inlet is arranged above the space between the annular strip-falling heat exchange tube bundle and the heat transfer oil reflux chamber.

[0008] Furthermore, the pressure of the pressurized operation is 0.1~1.0MPa (A), preferably 0.2~0.4MPa (A); the pressure of the reduced pressure evaporation is -0.08~ -0.05MPa (B); and the operating pressure of the initial degassing section is 0~0.5MPa (A).

[0009] Furthermore, the heating medium of the pre-degassing section is heat transfer oil or steam. When steam heating is adopted, the steam pressure is 0.3-0.5 MPa.

[0010] Furthermore, the temperature of the heat transfer oil at the inlet of the fine degassing section is higher than the temperature of the heat transfer oil at the inlet of the primary degassing section, and the temperature of the heat transfer oil at the inlet of the primary degassing section is 120-180°C.

[0011] In a second aspect, the present invention provides a high-efficiency devolatilization device suitable for use in a POE production process, the device comprising: a pre-devolatilization separation chamber, a pre-devolatilization heating chamber, a primary-devolatilization strip evaporator, and a fine-devolatilization strip evaporator; Both the primary stripping section and the fine stripping section adopt a single-tube-pass strip evaporator, including a separation chamber and a strip-type heating chamber located in the center of the inner cavity of the separation chamber; the strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil return chamber arranged in the central cavity of the annular strip heat exchange tube bundle, a heat transfer oil outlet is arranged at the upper end of the heat transfer oil return chamber, the upper end of the annular strip heat exchange tube bundle is connected to the heat transfer oil inlet, and the lower part of the annular strip heat exchange tube bundle is connected to the heat transfer oil return chamber through the lower tube compartment; a polymer inlet is arranged above the space between the annular strip heat exchange tube bundle and the heat transfer oil return chamber; The raw material liquid containing 70-90% light weight enters the pre-desorption separation chamber after heat exchange in the pre-desorption heating chamber. After the pre-desorption separation chamber performs gas-liquid separation, part of the liquid phase passes through the pre-desorption circulation pump and heat exchange in the pre-desorption heating chamber and enters the pre-desorption separation chamber again, and part of the liquid phase enters the polymer inlet of the primary desorption strip evaporator through the pre-desorption discharge pump; the gas phase separated in the pre-desorption separation chamber enters the pre-desorption condenser through the gas phase outlet at the top of the pre-desorption separation chamber 3, and the outlet of the pre-desorption condenser is connected to the pre-desorption light phase storage tank; The heat transfer oil inlet of the primary strip evaporator is connected to the outlet of the medium-temperature heat transfer oil furnace, and the heat transfer oil flows back to the medium-temperature heat transfer oil furnace through the heat transfer oil outlet on the heat transfer oil reflux chamber; the material enters through the polymer inlet along the wall surface of the heat transfer oil reflux chamber in the primary strip evaporator downward and diffuses to the gas-liquid separation space in the separation chamber of the primary strip evaporator to perform gas-liquid separation, and the separated gas phase is condensed by the primary strip condenser 6 and enters the primary strip light phase storage tank 12; the separated POE liquid enters the fine strip evaporator 11 through the primary strip discharge pump 13; The heat transfer oil inlet of the refined strip evaporator is connected to the outlet of the high-temperature heat transfer oil furnace, and the heat transfer oil returns to the high-temperature heat transfer oil furnace through the heat transfer oil outlet on the heat transfer oil reflux chamber; the material enters through the polymer inlet along the wall of the heat transfer oil reflux chamber in the refined strip evaporator and diffuses downward to the gas-liquid separation space in the separation chamber of the refined strip evaporator to perform gas-liquid separation, and the separated gas phase is condensed by the refined strip condenser 6 and enters the refined strip light phase storage tank 12; the separated POE liquid enters the next process of POE production through the refined strip discharge pump 13.

[0012] Furthermore, the outlet temperature of the high-temperature thermal oil furnace is higher than the outlet temperature of the medium-temperature thermal oil furnace, and the outlet temperature of the medium-temperature thermal oil furnace is not less than 120°C.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention innovatively adopts a three-stage concentration process of forced circulation pre-degassing, medium-temperature single-tube-pass strip evaporation primary degassing and high-temperature single-tube-pass strip evaporation fine degassing, and preferably adopts the operation mode of pressurized pre-degassing, normal pressure primary degassing and reduced pressure fine degassing. It can concentrate the light phase content in the POE raw material from the initial 70-90% to less than 1% at one time without the help of dynamic devolatilization and only using two-stage static devolatilization at a lower cost. It has the characteristics of high devolatilization efficiency, low energy consumption, large processing capacity, not easy to clog, etc., and can solve the bottleneck of difficult devolatilization in the existing POE production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Process flow chart of the present invention; Figure 2 The present invention is a schematic structural diagram of a single-pass strip evaporator according to an embodiment of the present invention.

[0015] In the figure, 1 is a condensed water tank, 2 is a pre-desorption heating chamber, 3 is a pre-desorption separation chamber, 4 is a pre-desorption condenser, 5 is a medium-temperature thermal oil furnace, 6 is a primary desorption condenser, 7 is a high-temperature thermal oil furnace, 8 is a fine desorption condenser, 9 is a fine desorption light phase storage tank, 10 is a fine desorption discharge pump, 11 is a fine desorption strip evaporator, 12 is a primary desorption light phase storage tank, 13 is a primary desorption discharge pump, 14 is a primary desorption strip evaporator, 15 is a pre-desorption light phase storage tank, 16 is a pre-desorption discharge pump, and 17 is a pre-desorption circulation pump; A separation chamber, B falling bar heating chamber, 21 annular falling bar heat exchange tube bundle, 22 upper tube sheet, 23 lower tube sheet, 24 upper tube compartment end cover, 25 lower tube compartment head, 26 reflux chamber, 261 shell and tube, 262 upper head, 231 through hole, 221 gap, 27 first annular baffle, 28 second annular baffle, 29 third annular baffle, N1 heat transfer oil inlet, N2 heat transfer oil outlet, N3 polymer inlet, N4 polymer outlet, N5 light component gas phase outlet. DETAILED DESCRIPTION

[0016] The technical solution is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0017] The present invention discloses a static and efficient devolatilization process suitable for POE production, which includes three sections: pre-devolatilization, primary devolatilization and fine devolatilization. The pre-devolatilization section adopts an external circulation enhanced heat transfer method, preferably steam is used as a heating medium, and a pressurized operation is performed to quickly remove the light phase in the raw material, so as to increase the viscosity of the feed liquid and reduce the subsequent concentration load; the primary devolatilization adopts strip-falling to enhance heat transfer, preferably a single-tube strip-falling evaporator is used, and medium-temperature heat transfer oil is used for heating, so as to further increase the heating temperature to ensure the fluidity of the material and further remove the light phase component in the feed liquid; the fine devolatilization still adopts a single-tube strip-falling evaporator to enhance heat transfer, and high-temperature heat transfer oil is used for heating, so as to remove the light phase in the material to the content index required by the process at one time, and preferably reduced pressure evaporation is used.

[0018] The equipment of the pre-degassing section mainly includes a heating chamber, a separator, a condenser, a forced circulation pump and a discharge pump. The process is as follows: Material flow: The raw material inlet liquid with a certain mass flow rate containing 70-90% light weight is first pressurized by the raw material pump and enters the pre-desorption heating chamber from the circulation pipe riser; after heating, the superheated liquid phase enters the separation chamber to achieve gas-liquid separation; part of the liquid phase enters the pre-desorption circulation pump 17 along the circulation pipe downcomer, mixes with the raw material inlet liquid after pressurization, and flows back to the pre-desorption heating chamber again. The pre-desorption discharge pump is a volumetric pump with a metering function, and is connected to the pre-desorption separation chamber 3 through a pipeline. Part of the liquid phase enters the next section through the pre-desorption discharge pump 16.

[0019] The gas phase enters the pre-desorption condenser 4 through the gas phase outlet at the top of the pre-desorption separation chamber 3, and enters the pre-desorption light phase storage tank 15 after condensation for recycling; further, the condensation pressure of the pre-desorption condenser 4 is 0.1~1.0MPa (A), and the preferred condenser pressure is 0.2~0.4MPa (A).

[0020] A large amount of light phase material can be removed by pressurized pre-desorption treatment, and the light phase content is controlled below 20% after pre-desorption treatment; Direction of heating medium: The heating medium of the pre-degassing section is heat transfer oil or steam. Steam heating is preferably used, and 0.3-0.5 MPa heating steam enters the shell side of the pre-degassing heating chamber 2 through a regulating valve, and after heat exchange with the raw material inlet liquid, the condensate enters the condensate tank 1.

[0021] The equipment of the primary stripping section mainly includes a strip evaporator and a discharge pump. Preferably, the strip evaporator adopts a single-tube strip evaporator and uses a jacket for heat preservation. The discharge pump adopts a gear pump with a metering function. The process is as follows: Material flow: The material after the discharge pump of the pre-desorption section enters the polymer holding chamber from the top of the primary strip evaporator 14, and under the action of the pump pressure, enters the fan-shaped strip gap formed by the overlapping fins, and after heat exchange with the high-temperature heat transfer oil in the tubes, it is discharged to the gas-liquid separation space of the primary strip heater; the gas phase enters the pre-desorption condenser 6 through the gas phase outlet at the top of the primary strip evaporator, and enters the primary desorption light phase storage tank 12 after condensation; further, the condensation pressure of the pre-desorption condenser 6 is 0-0.5MPa (A), and the preferred operating pressure of the pre-desorption condenser is 0.08-0.3MPa (A). The liquid phase falls into the lower space of the primary strip evaporator 14, enters the primary desorption discharge pump 13 through the liquid outlet, and enters the next section.

[0022] Direction of heating medium: The heat transfer oil enters the strip evaporator in two streams; The first stream: 120-180℃ heat transfer oil enters from the upper tube compartment of the strip heater of the primary strip evaporator, enters the lower head of the strip heater of the primary strip evaporator through the heat exchange tube bundle, and then flows back to the medium-temperature heat transfer oil furnace 5 from the heat transfer oil return port on the top of the strip heater of the strip evaporator through the heat transfer oil return chamber; The second stream: heat transfer oil at 150-250° C. enters the jacket from the heat transfer oil inlet of the jacket of the primary strip evaporator, flows out from the heat transfer oil outlet, and flows back to the high-temperature heat transfer oil furnace 7.

[0023] In the initial desulfurization stage, the light weight content is controlled at about 2.5-7% (mass content).

[0024] The equipment of the fine stripping section mainly includes a fine stripping stripping evaporator and a discharge pump. Preferably, the stripping stripping evaporator adopts a single-tube stripping evaporator and adopts a jacket for heat preservation. The discharge pump adopts a gear pump with a metering function. The process is as follows: Material flow: The material after the discharge pump 13 of the primary stripping section enters the polymer containing chamber from the top of the fine strip evaporator 11, and under the action of the pump pressure, enters the fan-shaped strip gap formed by the overlapping fins, and after heat exchange with the high-temperature heat transfer oil in the tubes, it is discharged to the gas-liquid separation space of the fine strip evaporator; the gas phase enters the fine strip condenser 8 through the gas phase outlet at the top of the fine strip evaporator, and enters the fine strip light phase storage tank 9 after condensation. The liquid phase falls into the lower space of the fine strip evaporator, enters the fine strip discharge pump 10 through the liquid outlet, and enters the extrusion granulation section.

[0025] Direction of heating medium: 150-250 degrees Celsius heat transfer oil enters the fine shedding strip evaporator in two streams; The first stream: 150-250℃ heat transfer oil enters from the upper tube compartment of the strip heater of the fine strip evaporator, enters the lower head of the strip heater of the fine strip evaporator through the heat exchange tube bundle, and then flows back to the high-temperature heat transfer oil furnace through the heat transfer oil reflux chamber and the heat transfer oil reflux port on the top of the strip heater of the fine strip evaporator; The second stream: heat transfer oil at 150-250° C. enters the jacket from the heat transfer oil inlet of the jacket of the fine shedding strip evaporator, flows out from the heat transfer oil outlet, and flows back to the high-temperature heat transfer oil furnace 7.

[0026] In the fine degassing section, the working pressure of the fine degassing condenser 8 is -0.08~ -0.05MPa (B), so that the light weight content is controlled within 1%, further controlled within 0.1~1%, preferably at ppm level. B represents the gauge pressure.

[0027] In the present invention, the condenser and the strip evaporator are connected, the condenser is decompressed, and the strip evaporator is operated under reduced pressure, and similarly, the condenser is pressurized, and the strip evaporator is operated under pressurization.

[0028] Example 1 This embodiment is applicable to the high-efficiency devolatilization process in the POE production process, wherein the devolatilization process mainly includes three stages: pre-devolatilization, primary devolatilization and fine devolatilization.

[0029] Pre-desorption section: The raw material at 60°C containing 85% light weight is heated in the pre-desorption heating chamber and then pumped into the pre-desorption separation chamber 3. Open the steam valve of the pre-desorption heating chamber 2. The heating steam of the pre-desorption heating chamber 2 uses 0.3MPa saturated steam. Adjust the opening of the steam valve to evaporate the material. During stable operation, that is, regardless of the start-up or shutdown or accident status, the pressure of the pre-desorption condenser 4 is maintained at 0.2MPa (A), and the condensed light phase is refluxed to the pre-desorption light phase storage tank 15. Under the premise that the liquid in the pre-desorption separation chamber 3 is relatively constant, adjust the steam inlet opening until the flow rate of the pre-desorption discharge pump 16 reaches 5-7 cubic meters / h, and maintain this flow rate so that the pre-desorption POE mixed liquid enters the next level of primary desorption section; Primary degassing section: POE liquid containing about 15-20% light weight and a temperature of about 80-90°C enters from the top inlet of the primary degassing strip evaporator 14. The material first flows downward along the wall surface of the heat transfer oil reflux chamber in the primary degassing strip evaporator, and then disperses into the gap space between the heat transfer fin components of the primary degassing strip evaporator, and exchanges heat with the heat transfer oil of the medium-temperature heat transfer oil furnace 5. The temperature is further increased to 100-150°C, and diffuses to the gas-liquid separation space outside the heat transfer oil reflux chamber in the primary degassing strip evaporator 14 to achieve gas-liquid separation; the gas phase enters the primary degassing condenser 6, and enters the primary degassing light phase storage tank 12 after condensation; the POE liquid enters the next-level fine degassing strip evaporator 11 through the primary degassing discharge pump 13. The inlet oil temperature of the medium-temperature heat transfer oil furnace 5 in this section is controlled at 150-180°C; the working pressure of the primary degassing condenser 6 is normal pressure.

[0030] Refining and degassing section: a POE liquid containing about 2.5-7% light weight and a temperature of about 100-150°C enters from the top inlet of the refined degassing strip evaporator 11, and the material first flows downward along the wall surface of the heat transfer oil reflux chamber in the refined degassing strip evaporator, and then fills the internal space and disperses into the gap space between the heat transfer fin components of the refined degassing strip evaporator, and exchanges heat with the heat transfer oil from the high-temperature heat transfer oil furnace 7. The temperature is further increased to 130-180°C, and diffuses to the gas-liquid separation space outside the heat transfer oil reflux chamber in the refined degassing strip evaporator to achieve gas-liquid separation; the gas phase enters the refined degassing condenser 8, and enters the refined degassing light phase storage tank 9 after condensation; the POE liquid containing 0.1-1% light phase enters the next process of POE production through the refined degassing discharge pump 10. The outlet oil temperature of the high-temperature heat-conducting oil furnace 7 in this section is controlled at 180-200°C; the working pressure of the fine degassing condenser 8 is 0.02-0.05MPa (A), where A represents absolute pressure.

[0031] Example 2 This embodiment is applicable to the efficient devolatilization process in the POE production process. The devolatilization process mainly includes three sections: pre-devolatilization, primary devolatilization and fine devolatilization. The pressure of the pre-devolatilization condenser in the pre-devolatilization section is maintained at 0.4MPa (A), and the light weight entering the primary devolatilization section is about 16-18%, and the working pressure of the primary devolatilization condenser 6 is 0.2MPa (A); entering the fine devolatilization section, the light weight is about 2.5-6%, and the working pressure of the fine devolatilization condenser 8 is 0.04MPa (A).

[0032] Example 3 The single-pass strip evaporator of this embodiment includes a separation chamber and a strip-type heating chamber located in the center of the inner cavity of the separation chamber; the strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil reflux chamber arranged in the central cavity of the annular strip heat exchange tube bundle, a heat transfer oil outlet is arranged at the upper end of the heat transfer oil reflux chamber, the upper end of the annular strip heat exchange tube bundle is connected to the heat transfer oil inlet, and the lower part of the annular strip heat exchange tube bundle is connected to the heat transfer oil reflux chamber through the lower tube compartment; a polymer inlet is arranged above the space between the annular strip heat exchange tube bundle and the heat transfer oil reflux chamber.

[0033] The devolatilizer adds a heat transfer oil reflux chamber in the central cavity of the annular strip heat exchange tube bundle, so that the heat transfer oil enters from the upper tube compartment of the devolatilizer, flows through the annular strip heat exchange tube bundle once, then enters the tube bundle head (i.e., the lower tube compartment), then turns back along the heat transfer oil reflux chamber, and finally is discharged from the heat transfer oil outlet on the end cover of the upper tube compartment of the devolatilizer. This is a single-pass flow process of the heat transfer oil.

[0034] Example 4 The single-pass strip evaporator in this embodiment includes a separation chamber A and a strip-type heating chamber B located in the center of the inner cavity of the separation chamber; the strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil reflux chamber 26 arranged in the central cavity of the annular strip heat exchange tube bundle, and a heat transfer oil outlet N2 is arranged at the upper end of the heat transfer oil reflux chamber 26, the upper end of the annular strip heat exchange tube bundle is connected to the heat transfer oil inlet N1, and the lower part of the annular strip heat exchange tube bundle is connected to the heat transfer oil reflux chamber 26 through the lower tube compartment; a polymer inlet N3 is arranged above the space between the annular strip heat exchange tube bundle and the heat transfer oil reflux chamber.

[0035] The stave-type heating chamber B comprises an annular stave heat exchange tube bundle 21, an upper tube sheet 22, a lower tube sheet 23, an upper tube compartment end cover 24, a lower tube compartment head 25, and a heat transfer oil reflux chamber 26; the annular stave heat exchange tube bundle comprises 4-10 layers of an equal number of heat exchange tubes distributed in an annular shape, and a plurality of groups of fins arranged in sequence and staggered along the axial direction of the heat exchange tubes; each fin in the fin group only penetrates two adjacent rows of heat exchange tubes to form a circular ring, and in the axial direction of the heat exchange tube, all the tubes are staggered from bottom to top, thereby dividing the internal space of the separation chamber into three parts: a gas-liquid separation chamber outside the fin group ring; a polymer containing cavity inside the fin group ring, and a plurality of heat transfer chambers formed between the overlapping fins.

[0036] The upper tube box is fixed above the upper tube plate, and the lower tube box is fixed below the lower tube plate. The heat transfer oil reflux chamber is located in the center of the polymer accommodating chamber, and includes a shell tube and an upper head. The lower end of the shell tube is connected to the lower tube box through the opening on the lower tube plate, and the upper end is connected to the upper head of the reflux chamber and passes through the upper tube plate, with a gap between the shell tube and the upper tube plate.

[0037] Furthermore, a first annular partition 27 is provided on the upper head of the heat transfer oil return chamber, and the first annular partition is sealed and connected to the upper head of the heat transfer oil return chamber and the end cover of the upper tube compartment of the strip-type heating chamber, and the outer side thereof is connected to the polymer inlet N3 by the space enclosed by the third annular partition 29 on the side wall of the upper tube compartment; inside the first annular partition, the central opening of the upper head of the return chamber is connected to the heat transfer oil outlet. The lower end of the shell and tube is fixedly sealed with the lower tube sheet, and a through hole is opened in the center of the lower tube sheet, through which the shell and tube are connected to the lower tube compartment, and the space enclosed by the shell and tube, the lower tube compartment head, and the upper head is the heat transfer oil return chamber.

[0038] The separation chamber A comprises a separation chamber shell, a light component gas phase outlet N5 and a polymer outlet N4. The separation chamber shell is connected to the upper tube plate of the falling bar heating chamber by bolts and is provided with a jacket for heat insulation.

[0039] Any matters not described in the present invention are applicable to the prior art.

Claims

1. An efficient devolatilization process suitable for POE production process, characterized in that: The process includes three sections: pre-degassing, primary degassing and fine degassing. The pre-degassing section adopts an external circulation enhanced heat transfer method to concentrate the light phase content from 70-90% to less than 20%. The initial stripping stage uses stripping to enhance heat transfer, so that the light weight content is controlled within the range of 2.5-7%; The fine stripping section adopts stripping to enhance heat transfer and reduces the pressure of evaporation to control the light weight content within 1%; Both the primary stripping section and the fine stripping section adopt a single-tube-pass strip-falling evaporator, including a separation chamber and a strip-falling heating chamber located in the center of the inner cavity of the separation chamber; the strip-falling heating chamber includes an annular strip-falling heat exchange tube bundle and a heat transfer oil reflux chamber arranged in the central cavity of the annular strip-falling heat exchange tube bundle, a heat transfer oil outlet is arranged at the upper end of the heat transfer oil reflux chamber, the upper end of the annular strip-falling heat exchange tube bundle is connected to the heat transfer oil inlet, and the lower part of the annular strip-falling heat exchange tube bundle is connected to the heat transfer oil reflux chamber through a lower tube compartment; a polymer inlet is arranged above the space between the annular strip-falling heat exchange tube bundle and the heat transfer oil reflux chamber.

2. The process according to claim 1, characterized in that The pressure of the pressurized operation is 0.1~1.0MPa (A), preferably 0.2~0.4MPa (A); the pressure of the reduced pressure evaporation is -0.08~ -0.05MPa; the operating pressure of the initial degassing section is 0~0.5MPa (A).

3. The process according to claim 1, characterized in that The heating medium of the pre-desorption section is heat transfer oil or steam. When steam heating is adopted, the steam pressure is 0.3-0.5 MPa.

4. The process according to claim 1, characterized in that The temperature of the heat transfer oil at the inlet of the fine degassing section is higher than the temperature of the heat transfer oil at the inlet of the primary degassing section, and the temperature of the heat transfer oil at the inlet of the primary degassing section is 120-180°C.

5. An efficient devolatilization device suitable for POE production process, characterized in that: The equipment comprises: a pre-desorption separation chamber, a pre-desorption heating chamber, a primary desorption strip evaporator, and a fine desorption strip evaporator; Both the primary stripping section and the fine stripping section adopt a single-tube-pass strip evaporator, including a separation chamber and a strip-type heating chamber located in the center of the inner cavity of the separation chamber; the strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil return chamber arranged in the central cavity of the annular strip heat exchange tube bundle, a heat transfer oil outlet is arranged at the upper end of the heat transfer oil return chamber, the upper end of the annular strip heat exchange tube bundle is connected to the heat transfer oil inlet, and the lower part of the annular strip heat exchange tube bundle is connected to the heat transfer oil return chamber through the lower tube compartment; a polymer inlet is arranged above the space between the annular strip heat exchange tube bundle and the heat transfer oil return chamber; The raw material liquid containing 70-90% light weight enters the pre-desorption separation chamber after heat exchange in the pre-desorption heating chamber. After the pre-desorption separation chamber performs gas-liquid separation, part of the liquid phase passes through the pre-desorption circulation pump and heat exchange in the pre-desorption heating chamber and enters the pre-desorption separation chamber again, and part of the liquid phase enters the polymer inlet of the primary desorption strip evaporator through the pre-desorption discharge pump; the gas phase separated in the pre-desorption separation chamber enters the pre-desorption condenser through the gas phase outlet at the top of the pre-desorption separation chamber 3, and the outlet of the pre-desorption condenser is connected to the pre-desorption light phase storage tank; The heat transfer oil inlet of the primary strip evaporator is connected to the outlet of the medium-temperature heat transfer oil furnace, and the heat transfer oil flows back to the medium-temperature heat transfer oil furnace through the heat transfer oil outlet on the heat transfer oil reflux chamber; the material enters through the polymer inlet along the wall of the heat transfer oil reflux chamber in the primary strip evaporator downward and diffuses to the gas-liquid separation space in the separation chamber of the primary strip evaporator to perform gas-liquid separation, and the separated gas phase is condensed by the primary strip condenser and enters the primary strip light phase storage tank; the separated POE liquid enters the fine strip evaporator through the primary strip discharge pump; The heat transfer oil inlet of the refined shedding strip evaporator is connected to the outlet of the high-temperature heat transfer oil furnace, and the heat transfer oil returns to the high-temperature heat transfer oil furnace through the heat transfer oil outlet on the heat transfer oil reflux chamber; the material enters through the polymer inlet along the wall of the heat transfer oil reflux chamber in the refined shedding strip evaporator and diffuses downward to the gas-liquid separation space in the separation chamber of the refined shedding strip evaporator to perform gas-liquid separation, and the separated gas phase is condensed by the refined degassing condenser and enters the refined degassing light phase storage tank; the separated POE liquid enters the next process of POE production through the refined degassing discharge pump.

6. The device according to claim 5, characterized in that The outlet temperature of the high-temperature thermal oil furnace is higher than the outlet temperature of the medium-temperature thermal oil furnace, and the outlet temperature of the medium-temperature thermal oil furnace is not less than 120°C.

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