High-efficiency devolatilization process and equipment suitable for POE production process

Abstract

The application discloses a high-efficiency devolatilization process and equipment suitable for a POE production process. The process comprises three sections of pre-devolatilization, primary devolatilization and fine devolatilization. The pre-devolatilization section concentrates the light phase content from 70-90% to 20% or below. The primary devolatilization and fine devolatilization sections adopt falling-film enhanced heat transfer. The light content in the primary devolatilization section is controlled in the range of 2.5-7%, and the light content in the fine devolatilization section is controlled to be 1% or below. The primary devolatilization section and the fine devolatilization section both adopt single-tube falling-film evaporators, which comprise a separation chamber and a falling-film heating chamber in the central cavity of the separation chamber. The falling-film heating chamber comprises annular falling-film heat exchange tube bundles and a heat-conducting oil return chamber arranged in the central cavity of the annular falling-film heat exchange tube bundles. The heat-conducting oil return chamber is provided with a heat-conducting oil outlet at the upper end. A polymer inlet is arranged above the space between the annular falling-film heat exchange tube bundles and the heat-conducting oil return chamber. The process can realize one-time devolatilization of reaction polymer materials containing a large amount of solvent, and directly reach the light phase content index of 1% or below, even reaching the requirement of PPM level.

Description

Technical Field

[0001] This invention belongs to the field of heat transfer and chemical separation, specifically relating to an efficient devolatilization process and equipment suitable for POE production, used for the heating and devolatilization process of polymer PEO. Background Technology

[0002] Polyethylene oxide (PEO) is a thermoplastic, water-soluble polymer with advantages such as good water solubility, low toxicity, and ease of processing and molding, making it a promising material for applications. In the PEO production process, after the devolatilization stage, the product is directly extruded and granulated. Since the content of the light phase component directly affects the product's quality grade, the devolatilization stage is crucial throughout the entire production process. However, as a high-viscosity, low-thermal-conductivity substance, the devolatilization process of POE has always been challenging. This is mainly due to the following: the initial feed liquid, i.e., the product from the self-reactive polymerization stage, has a high light phase content, requiring a large heat exchange area for rapid solvent removal; as the solvent is removed, the material volumetric flow rate decreases, and the thermal conductivity drops rapidly, necessitating a more optimized heat transfer method; when the solvent content in POE continues to decrease, although the heat required for solvent evaporation is small, it is difficult to transfer heat effectively, thus requiring a higher heat transfer driving force, i.e., a higher heating temperature. However, excessively high temperatures can lead to plasticization or even charring of POE.

[0003] Currently, the process routes for POE devolatilization in my country are largely the same, mostly adopting a method of preheating at the front end and then using high-efficiency heat transfer equipment for flash evaporation in one go. The flash evaporation method results in a large difference in the removal effect of light phases between the material wall and the interior, and poor uniformity.

[0004] To enhance heat transfer efficiency during POE devolatilization, current industrial devolatilization processes often combine static and dynamic methods to control the light phase content below 1%. However, this approach relies on dynamic devolatilization, which requires equipment with stirring devices such as scrapers and screws to forcibly agitate the high-viscosity fluid and enhance heat transfer. While this can increase heat transfer efficiency to some extent, high-viscosity PEO still suffers from issues like wall adhesion and localized overheating. Furthermore, forced stirring using rotary machinery has drawbacks such as small heat exchange area, high manufacturing and maintenance costs, and difficulty in scaling up and cleaning due to small throughput. For high-viscosity liquids, even with a three-stage static devolatilization cascade treatment, the light phase content in the POE product only maintains above 1% (2.5%-4.8%), and the quality of the granulated product falls far short of the requirements for high-quality products.

[0005] Therefore, it is crucial to develop an efficient devolatilization process suitable for POE production that can control the light phase content to within 1% without combining dynamic devolatilization. This is essential for accelerating the localization of POE production in my country. Summary of the Invention

[0006] The purpose of this invention is to provide a highly efficient static devolatilization process and equipment suitable for POE production, to solve the defects of existing static devolatilization processes, such as insufficient preheating, low efficiency of the main heat transfer equipment, and high light phase content of POE after devolatilization. Using the process of this invention, reactive polymer materials containing a large amount of solvent can be staged and devolatilized in a single step to achieve a light phase content of no more than 1%, or even reaching the PPM level.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect, the present invention provides an efficient devolatilization process applicable to the production process of POE. The process includes three stages: pre-devolatilization, primary devolatilization and fine devolatilization. The pre-devolatilization stage adopts an external circulation enhanced heat transfer method to concentrate the light phase content from 70-90% to less than 20%.

[0009] The initial stripping section uses strip-assisted heat transfer enhancement to keep the lightweight content within the range of 2.5-7%;

[0010] The fine stripping section uses a drop-bar heat transfer enhancement and reduced pressure evaporation to keep the light content below 1%.

[0011] Both the primary stripping section and the fine stripping section employ single-tube evaporators, including a separation chamber and a strip-type heating chamber located in the center of the separation chamber. The strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil reflux chamber located in the central cavity of the annular strip heat exchange tube bundle. A heat transfer oil outlet is provided 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 a lower tube box. A polymer inlet is provided above the space between the annular strip heat exchange tube bundle and the heat transfer oil reflux chamber.

[0012] Further, the pressure of the pressurization operation is 0.1~1.0MPa (A), preferably 0.2~0.4MPa (A); the pressure of the depressurization evaporation is -0.08~-0.05MPa (B); and the operating pressure of the initial desulfurization section is 0~0.5MPa (A).

[0013] Furthermore, the heating medium for the pre-de-stripping section is heat transfer oil or steam. When steam heating is used, the steam pressure is 0.3~0.5MPa.

[0014] Furthermore, the temperature of the heat transfer oil at the inlet of the fine stripping section is higher than that at the inlet of the heat transfer oil in the primary stripping section, where the temperature is 120-180℃.

[0015] Secondly, the present invention provides a high-efficiency devolatilization device suitable for the 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;

[0016] Both the primary stripping section and the fine stripping section employ single-tube evaporators, including a separation chamber and a strip-type heating chamber located in the center of the separation chamber. The strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil reflux chamber located in the central cavity of the annular strip heat exchange tube bundle. A heat transfer oil outlet is provided 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 a lower tube box. A polymer inlet is provided above the space between the annular strip heat exchange tube bundle and the heat transfer oil reflux chamber.

[0017] The raw material liquid containing 70-90% light content enters the pre-desorption heating chamber after heat exchange in the pre-desorption heating chamber. After gas-liquid separation in the pre-desorption separation chamber, part of the liquid phase enters the pre-desorption separation chamber again after heat exchange in the pre-desorption heating chamber via the pre-desorption circulation pump, and part of the liquid phase enters the polymer inlet of the primary desorption strip evaporator via 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. The outlet of the pre-desorption condenser is connected to the pre-desorption light phase storage tank.

[0018] The heat transfer oil inlet of the primary strip evaporator is connected to the outlet of the medium-temperature heat transfer oil furnace. 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 return chamber. The material enters the gas-liquid separation space in the separation chamber of the primary strip evaporator through the polymer inlet and diffuses downward along the wall of the heat transfer oil return chamber. Gas-liquid separation is carried out. 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.

[0019] The heat transfer oil inlet of the fine strip evaporator is connected to the outlet of the high-temperature heat transfer oil furnace. The heat transfer oil flows back to the high-temperature heat transfer oil furnace through the heat transfer oil outlet on the heat transfer oil return chamber. The material enters the gas-liquid separation space in the separation chamber of the fine strip evaporator through the polymer inlet and diffuses downward along the wall of the heat transfer oil return chamber. Gas-liquid separation is carried out. The separated gas phase is condensed by the fine strip condenser 6 and enters the fine strip light phase storage tank 12. The separated POE liquid is then entered into the next process of POE production by the fine strip discharge pump 13.

[0020] Furthermore, the outlet temperature of the high-temperature thermal oil furnace is higher than that of the medium-temperature thermal oil furnace, and the outlet temperature of the medium-temperature thermal oil furnace is not lower than 120℃.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention innovatively adopts a three-stage concentration process: forced circulation pre-desorption, medium-temperature single-pass drop-off evaporation initial desorption, and high-temperature single-pass drop-off evaporation fine desorption. It also optimizes the operation mode of pressurized pre-desorption, atmospheric pressure initial desorption, and depressurized fine desorption. Without relying on dynamic devolvation, it can concentrate the light phase content in POE raw materials from about 70-90% to less than 1% in one step with only two stages of static devolvation. It has the characteristics of high devolvation efficiency, low energy consumption, large processing capacity, and less clogging, and can solve the bottleneck of difficult devolvation in the existing POE production process. Attached Figure Description

[0023] Figure 1 Process flow diagram of this invention;

[0024] Figure 2 This is a schematic diagram of the structure of a single-pass evaporator according to an embodiment of the present invention.

[0025] In the diagram, 1 is the condensate tank, 2 is the pre-desorption heating chamber, 3 is the pre-desorption separation chamber, 4 is the pre-desorption condenser, 5 is the medium-temperature thermal oil furnace, 6 is the primary desorption condenser, 7 is the high-temperature thermal oil furnace, 8 is the fine desorption condenser, 9 is the fine desorption light phase storage tank, 10 is the fine desorption discharge pump, 11 is the fine desorption strip evaporator, 12 is the primary desorption light phase storage tank, 13 is the primary desorption discharge pump, 14 is the primary desorption strip evaporator, 15 is the pre-desorption light phase storage tank, 16 is the pre-desorption discharge pump, and 17 is the pre-desorption circulation pump.

[0026] A. Separation chamber; B. Drop-bar heating chamber; 21. Annular drop-bar heat exchange tube bundle; 22. Upper tube sheet; 23. Lower tube sheet; 24. Upper tube box end cap; 25. Lower tube box end cap; 26. Reflux chamber; 261. Shell and tube; 262. Upper end cap; 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 Implementation

[0027] The present technical solution will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0028] This invention discloses a static, high-efficiency devolatilization process suitable for POE production, comprising three stages: pre-devolatilization, primary devolatilization, and final devolatilization. The pre-devolatilization stage employs an external circulation system to enhance heat transfer, preferably using steam as the heating medium. Pressurized operation rapidly removes the light phase from the raw material, increasing the viscosity of the liquid and reducing the load on subsequent concentration. Primary devolatilization utilizes a sheet-fed evaporator to enhance heat transfer, preferably a single-tube sheet-fed evaporator heated by medium-temperature thermal oil, further increasing the heating temperature to ensure material flowability and further removing the light phase components from the liquid. Final devolatilization also employs a single-tube sheet-fed evaporator to enhance heat transfer, heated by high-temperature thermal oil, removing the light phase from the material to the required content level in a single pass; vacuum evaporation is preferred.

[0029] The pre-de-scraping section mainly includes a heating chamber, a separator, a condenser, a forced circulation pump, and a discharge pump. Its process is as follows:

[0030] Material flow: A certain mass flow rate of raw material with a light content of 70-90% is fed into the liquid. First, it is pressurized by the raw material pump and then enters the pre-desorption heating chamber through the circulating pipe riser. After heating, the superheated liquid phase enters the separation chamber for gas-liquid separation. A portion of the liquid phase flows down the circulating pipe into the pre-desorption circulating pump 17, where it is pressurized and mixed with the raw material feed, then flows back to the pre-desorption heating chamber. The pre-desorption discharge pump is a volumetric pump with metering function and is connected to the pre-desorption separation chamber 3 via pipeline. A portion of the liquid phase passes through the pre-desorption discharge pump 16 and enters the next stage.

[0031] 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 after condensation, it enters the pre-desorption light phase storage tank 15 for recycling; furthermore, 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).

[0032] A large amount of light phase material can be removed by pressure pre-removal treatment, and the light phase content is controlled below 20% after pre-removal treatment;

[0033] Heating medium flow: The heating medium in the pre-stripping section is heat transfer oil or steam. Steam heating is preferred. Heating steam at 0.3~0.5MPa enters the shell side of the pre-stripping heating chamber 2 through a regulating valve. After exchanging heat with the raw material feed liquid, the condensate enters the condensate tank 1.

[0034] The primary stripping section mainly includes a strip-falling evaporator and a discharge pump. Preferably, the strip-falling evaporator is a single-pass strip-falling evaporator with jacket insulation, and the discharge pump is a gear pump with metering function. The process is as follows:

[0035] Material flow: The material after the discharge pump of the pre-stripping section enters the polymer receiving chamber from the top of the primary stripping evaporator 14. Under the action of pump pressure, it enters the fan-shaped gaps formed by the overlapping fins, exchanges heat with the high-temperature heat transfer oil in the tubes, and is then discharged to the gas-liquid separation space of the primary stripping heater. The gas phase enters the pre-stripping condenser 6 through the gas phase outlet at the top of the primary stripping evaporator, and after condensation, enters the primary stripping light phase storage tank 12. Further, the condensation pressure of the pre-stripping condenser 6 is 0-0.5 MPa (A), and the preferred operating pressure of the pre-stripping condenser is 0.08-0.3 MPa (A). The liquid phase falls into the lower space of the primary stripping evaporator 14, enters the primary stripping discharge pump 13 through the liquid outlet, and enters the next stage.

[0036] Heating medium flow: The heat transfer oil enters the evaporator in two streams;

[0037] The first stream: heat transfer oil at 120-180℃ enters from the upper tube chamber of the deflection type heater of the initial deflection evaporator, enters the lower end cap of the deflection type heater of the initial deflection evaporator through the heat exchange tube bundle, and then flows back to the medium temperature heat transfer oil furnace 5 through the heat transfer oil return chamber and the top heat transfer oil return port of the deflection type heater of the deflection evaporator.

[0038] The second stream: heat transfer oil at 150-250℃ enters the jacket of the evaporator jacket through the heat transfer oil inlet, flows out through the heat transfer oil outlet, and flows back to the high-temperature heat transfer oil furnace 7.

[0039] The initial stripping process controls the light content to approximately 2.5-7% (by mass).

[0040] The fine stripping section mainly includes a fine stripping evaporator and a discharge pump. Preferably, the evaporator is a single-pass evaporator with jacket insulation, and the discharge pump is a gear pump with metering function. The process is as follows:

[0041] Material flow: The material after the discharge pump 13 in the primary stripping section enters the polymer receiving chamber from the top of the fine stripping evaporator 11. Under pump pressure, it enters the fan-shaped gaps formed by the overlapping fins, exchanges heat with the high-temperature heat transfer oil in the tubes, and is then discharged into the gas-liquid separation space of the fine stripping evaporator. The gas phase enters the fine stripping condenser 8 through the gas phase outlet at the top of the fine stripping evaporator, and after condensation, enters the fine stripping light phase storage tank 9. The liquid phase falls into the lower space of the fine stripping evaporator, enters the fine stripping discharge pump 10 through the liquid outlet, and enters the extrusion granulation section.

[0042] Heating medium flow: 150-250 degrees Celsius heat transfer oil enters the fine strip evaporator in two streams;

[0043] The first stream: heat transfer oil at 150-250℃ enters from the upper tube chamber of the delaminated evaporator, passes through the heat exchange tube bundle into the lower end cap of the delaminated evaporator, and then flows back to the high-temperature heat transfer oil furnace through the heat transfer oil return chamber and the top heat transfer oil return port of the delaminated evaporator.

[0044] The second stream: heat transfer oil at 150-250℃ enters the jacket of the evaporator through the heat transfer oil inlet and flows out through the heat transfer oil outlet, returning to the high-temperature heat transfer oil furnace 7.

[0045] In the fine removal section, the working pressure of the fine removal condenser 8 is -0.08~-0.05MPa (B), which controls the light content to within 1%, and further to 0.1~1%, preferably at the ppm level. B represents the gauge pressure.

[0046] In this invention, the condenser and the evaporator are connected. The condenser is depressurized and the evaporator is depressurized. Similarly, the condenser is pressurized and the evaporator is pressurized.

[0047] Example 1

[0048] This embodiment applies to the efficient devolatilization process in POE production. The devolatilization process mainly includes three stages: pre-devolatilization, initial devolatilization, and final devolatilization.

[0049] Pre-desorption section: Raw materials containing 85% light content at 60°C are heated in the pre-desorption heating chamber and then pumped into the pre-desorption separation chamber 3. The steam valve of the pre-desorption heating chamber 2 is opened. The heating steam for the pre-desorption heating chamber 2 is saturated steam at 0.3 MPa. The steam valve opening is adjusted to evaporate the material. During stable operation, i.e., without considering start-up, shutdown, or accidents, the pressure of the pre-desorption condenser 4 is maintained at 0.2 MPa (A). The condensed light phase is returned to the pre-desorption light phase storage tank 15. Under the premise of a relatively constant liquid phase in the pre-desorption separation chamber 3, the steam inlet opening is adjusted until the flow rate of the pre-desorption discharge pump 16 reaches 5-7 cubic meters per hour, and this flow rate is maintained, allowing the pre-desorbed POE mixture to enter the next stage of the primary desorption section.

[0050] Primary stripping section: A POE liquid containing approximately 15-20% light content and at a temperature of approximately 80-90℃ enters from the top inlet of the primary stripping evaporator 14. The material first flows downwards along the wall of the heat transfer oil return chamber in the primary stripping evaporator, then disperses into the gap space between the heat transfer fins of the primary stripping evaporator, exchanging heat with the heat transfer oil in the medium-temperature heat transfer oil furnace 5. The temperature further increases to 100-150℃, and then diffuses into the gas-liquid separation space outside the heat transfer oil return chamber of the primary stripping evaporator 14, achieving gas-liquid separation. The gas phase enters the primary stripping condenser 6, and after condensation, enters the primary stripping light phase storage tank 12. The POE liquid then enters the next stage, the fine stripping evaporator 11, via the primary stripping discharge pump 13. The inlet oil temperature of the medium-temperature heat transfer oil furnace 5 in this section is controlled at 150-180℃; the operating pressure of the primary stripping condenser 6 is atmospheric pressure.

[0051] Fine Desulfurization Section: POE liquid containing approximately 2.5-7% light phase and at a temperature of approximately 100-150℃ enters from the top inlet of the fine desulfurization evaporator 11. The material first flows downwards along the wall of the heat transfer oil return chamber in the fine desulfurization evaporator, then fills the internal space and disperses into the gap space between the heat transfer fin assemblies of the fine desulfurization evaporator, where it exchanges heat with the heat transfer oil from the high-temperature heat transfer oil furnace 7, further increasing the temperature to 130-180℃, and then diffuses into the gas-liquid separation space outside the heat transfer oil return chamber of the fine desulfurization evaporator, achieving gas-liquid separation. The gas phase enters the fine desulfurization condenser 8, and after condensation, enters the fine desulfurization light phase storage tank 9; the POE liquid containing 0.1-1% light phase is then pumped by the fine desulfurization discharge pump 10 to the next process in POE production. The outlet oil temperature of the high-temperature thermal oil furnace 7 in this section is controlled at 180-200℃; the working pressure of the fine decondenser 8 is 0.02~0.05MPa (A), where A represents absolute pressure.

[0052] Example 2

[0053] This embodiment applies to the efficient devolatilization process in POE production. The devolatilization process mainly includes three stages: pre-devolatilization, primary devolatilization, and final devolatilization. In the pre-devolatilization stage, the pressure of the pre-devolatilization condenser is maintained at 0.4 MPa (A), and the light content entering the primary devolatilization stage is approximately 16-18%, with the working pressure of the primary devolatilization condenser 6 at 0.2 MPa (A). Entering the final devolatilization stage, the light content is approximately 2.5-6%, with the working pressure of the final devolatilization condenser 8 at 0.04 MPa (A).

[0054] Example 3

[0055] This embodiment of a single-pass evaporator includes a separation chamber and a scallop heating chamber located in the center of the separation chamber. The scallop heating chamber includes an annular scallop heat exchange tube bundle and a heat transfer oil reflux chamber disposed in the central cavity of the annular scallop heat exchange tube bundle. A heat transfer oil outlet is provided at the upper end of the heat transfer oil reflux chamber. The upper end of the annular scallop heat exchange tube bundle is connected to a heat transfer oil inlet, and the lower part of the annular scallop heat exchange tube bundle is connected to the heat transfer oil reflux chamber through a lower tube box. A polymer inlet is provided above the space between the annular scallop heat exchange tube bundle and the heat transfer oil reflux chamber.

[0056] This devolatilizer achieves a single-pass flow process of heat transfer oil by adding a heat transfer oil return chamber in the central cavity of the annular strip heat exchanger tube bundle. The heat transfer oil enters from the upper tube box of the devolatilizer, flows through the annular strip heat exchanger tube bundle once, then enters the tube bundle head (i.e., the lower tube box), then turns back along the heat transfer oil return chamber, and finally exits from the heat transfer oil outlet on the end cover of the upper tube box of the devolatilizer.

[0057] Example 4

[0058] In this embodiment, a single-pass evaporator includes a separation chamber A and a slat-type heating chamber B located in the center of the separation chamber. The slat-type heating chamber includes an annular slat-type heat exchange tube bundle and a heat transfer oil reflux chamber 26 disposed in the central cavity of the annular slat-type heat exchange tube bundle. A heat transfer oil outlet N2 is provided at the upper end of the heat transfer oil reflux chamber 26. The upper end of the annular slat-type heat exchange tube bundle is connected to a heat transfer oil inlet N1, and the lower part of the annular slat-type heat exchange tube bundle is connected to the heat transfer oil reflux chamber 26 through a lower tube box. A polymer inlet N3 is provided above the space between the annular slat-type heat exchange tube bundle and the heat transfer oil reflux chamber.

[0059] The drop-bar heating chamber B includes an annular drop-bar heat exchange tube bundle 21, an upper tube sheet 22, a lower tube sheet 23, an upper tube end cap 24, a lower tube end cap 25, and a heat transfer oil return chamber 26. The annular drop-bar heat exchange tube bundle includes 4-10 layers of equally distributed heat exchange tubes in an annular shape, and several sets of fins arranged alternately along the axial direction of the heat exchange tubes. Each fin in the fin set penetrates only two adjacent rows of heat exchange tubes, forming a ring. In the axial direction of the heat exchange tubes, the entire tube is arranged alternately from bottom to top, thereby dividing the internal space of the separation chamber into three parts: a gas-liquid separation chamber outside the fin ring; a polymer receiving chamber inside the fin ring; and numerous heat transfer chambers formed between the overlapping fins.

[0060] The upper tube box is fixed above the upper tube sheet, and the lower tube box is fixed below the lower tube sheet. The heat transfer oil reflux chamber is located in the center of the polymer receiving cavity and includes a shell tube and an upper end cap. The lower end of the shell tube communicates with the lower tube box through an opening on the lower tube sheet, and the upper end is connected to the upper end cap of the reflux chamber and passes through the upper tube sheet, with a gap between the shell tube and the upper tube sheet.

[0061] Furthermore, a first annular baffle 27 is provided on the upper end cap of the heat transfer oil reflux chamber. The first annular baffle is sealed and connected to the upper end cap of the heat transfer oil reflux chamber and the end cap of the upper tube box of the drop-bar heating chamber. The space enclosed by the first annular baffle and the third annular baffle 29 on the side wall of the upper tube box is connected to the polymer inlet N3. Inside the first annular baffle, a central opening is made on the upper end cap of the reflux chamber, which is connected to the heat transfer oil outlet. The lower end of the shell tube is fixedly sealed to the lower tube sheet. A through hole is opened in the center of the lower tube sheet, through which the shell tube communicates with the lower tube box. The space enclosed by the shell tube, the lower tube box end cap, and the upper end cap is the heat transfer oil reflux chamber.

[0062] The separation chamber A includes 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 sheet of the drop-bar heating chamber by bolts and is equipped with a jacket for heat preservation.

[0063] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A highly efficient devolatilization process suitable for POE production, characterized in that, The process includes three stages: pre-desorption, primary desorption, and fine desorption. The pre-desorption stage adopts an external circulation enhanced heat transfer method to control the light phase content from 70-90% to less than 20%. The initial stripping section uses strip-assisted heat transfer enhancement to keep the light content within the range of 2.5-7%; the heat transfer oil temperature at the inlet of the initial stripping section is 120-180℃. The fine stripping section uses a drop-bar heat transfer enhancement and reduced pressure evaporation to keep the light content below 1%. Both the primary stripping section and the fine stripping section employ single-tube evaporators, including a separation chamber and a strip-type heating chamber located in the center of the separation chamber. The strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil reflux chamber located in the central cavity of the annular strip heat exchange tube bundle. A heat transfer oil outlet is provided 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 a lower tube box. A polymer inlet is provided above the space between the annular strip heat exchange tube bundle and the heat transfer oil reflux chamber. The annular strip heat exchange tube bundle includes 4-10 layers of equally distributed heat exchange tubes in a ring shape, and several sets of fins arranged alternately along the axial direction of the heat exchange tubes. Each fin in the fin set penetrates only two adjacent rows of heat exchange tubes, forming a ring. The entire tube is arranged alternately from bottom to top along the axial direction of the heat exchange tubes, thereby dividing the internal space of the separation chamber into three parts: the gas-liquid separation chamber outside the fin ring; the polymer receiving chamber inside the fin ring; and the numerous heat transfer chambers formed between the overlapping fins.

2. The process according to claim 1, characterized in that, The absolute pressure of the pre-de-descaling section is 0.1~1.0MPa; the gauge pressure of the reduced pressure evaporation is -0.08~-0.05MPa; and the absolute pressure of the initial de-descaling section is 0~0.5MPa.

3. The process according to claim 2, characterized in that, The absolute pressure of the pre-de-processing section pressurization operation is 0.2~0.4MPa.

4. The process according to claim 1, characterized in that, The heating medium for the pre-de-stripping section is heat transfer oil or steam. When steam heating is used, the steam pressure is 0.3~0.5MPa.

5. The process according to claim 1, characterized in that, The temperature of the heat transfer oil at the inlet of the fine stripping section is higher than that at the inlet of the heat transfer oil in the primary stripping section.

6. A high-efficiency devolatilization device suitable for POE production process, characterized in that, The equipment includes: a pre-de-stripping separation chamber, a pre-de-stripping heating chamber, a primary de-stripping evaporator, and a fine de-stripping evaporator; Both the primary stripping section and the fine stripping section employ single-tube evaporators, including a separation chamber and a strip-type heating chamber located in the center of the separation chamber. The strip-type heating chamber includes an annular strip heat exchange tube bundle and a heat transfer oil reflux chamber located in the central cavity of the annular strip heat exchange tube bundle. A heat transfer oil outlet is provided 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 a lower tube box. A polymer inlet is provided above the space between the annular strip heat exchange tube bundle and the heat transfer oil reflux chamber. The annular strip heat exchange tube bundle includes 4-10 layers of equally distributed heat exchange tubes in a ring shape, and several sets of fins arranged alternately along the axial direction of the heat exchange tubes; each fin in the fin set penetrates only two adjacent rows of heat exchange tubes, forming a ring shape, and the entire tube is arranged alternately from bottom to top along the axial direction of the heat exchange tubes, thereby dividing the internal space of the separation chamber into three parts: the gas-liquid separation chamber outside the fin ring; the polymer receiving chamber inside the fin ring; and the numerous heat transfer chambers formed between the overlapping fins; The raw material liquid containing 70-90% light content enters the pre-desorption heating chamber after heat exchange in the pre-desorption heating chamber. After gas-liquid separation in the pre-desorption separation chamber, part of the liquid phase enters the pre-desorption separation chamber again after heat exchange in the pre-desorption heating chamber via the pre-desorption circulation pump, and part of the liquid phase enters the polymer inlet of the primary desorption strip evaporator via 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. 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. 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 return chamber. The material enters the gas-liquid separation space in the separation chamber of the primary strip evaporator through the polymer inlet and diffuses downward along the wall of the heat transfer oil return chamber. Gas-liquid separation is carried out. The separated gas phase is condensed by the primary strip condenser and enters the primary strip light phase storage tank. The separated POE liquid is then pumped into the fine strip evaporator by the primary strip discharge pump. The heat transfer oil inlet of the fine strip evaporator is connected to the outlet of the high-temperature heat transfer oil furnace. The heat transfer oil flows back to the high-temperature heat transfer oil furnace through the heat transfer oil outlet on the heat transfer oil return chamber. The material enters the gas-liquid separation space in the separation chamber of the fine strip evaporator through the polymer inlet and diffuses downward along the wall of the heat transfer oil return chamber. Gas-liquid separation is carried out. The separated gas phase is condensed by the fine strip condenser and enters the fine strip light phase storage tank. The separated POE liquid is then sent to the next process of POE production by the fine strip discharge pump.

7. The device according to claim 6, characterized in that, The outlet temperature of a high-temperature thermal oil furnace is higher than that of a medium-temperature thermal oil furnace, while the outlet temperature of a medium-temperature thermal oil furnace is not lower than 120℃.

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