Polymer volatile matter removal and recovery device

Abstract

The utility model relates to a polymer volatile matter removal and recovery device, which belongs to the technical field of separation and comprises a primary positive pressure evaporation unit, a secondary vacuum extraction unit and a volatile matter recovery unit, and the primary positive pressure evaporation unit comprises a rising film type preheating evaporator, a flash separation mechanism and a falling film evaporator. And the secondary vacuum extraction unit comprises a feed heater, a gas stripping tower and a gas stripping tower gas-liquid separation module. The volatile matter recovery unit comprises a volatile matter recovery tower, a gas-phase volatile matter recovery module, a high-purity elementary substance or solvent collection module, a heavy component impurity collection module and a volatile matter recovery and reboiling module. According to the utility model, the foaming efficiency and the mass transfer area in the evaporation process are enhanced, the content of volatile matters in a polymer can be reduced to be below 0.1 wt% through two-stage evaporation, the polymer is effectively prevented from being deteriorated at high temperature in the evaporation process, the device is suitable for devolatilization of a heat-sensitive polymer, and meanwhile, the removed monomer and solvent are recycled and reused.

Description

Technical Field

[0001] The utility model relates to the field of separation technology, in particular to a polymer volatile matter removal and recovery device. Background Art

[0002] The industrial production process of polymers usually consists of the following steps: monomer synthesis and purification, monomer polymerization, solvent or monomer separation and recovery, and polymer processing. Before entering the polymer processing, various volatile components in the polymerization system, such as unreacted monomers, solvents, water, and various polymerization by-products, are required to be separated to improve the performance of the polymer. The volatile components are called "volatiles" and the process is called devolatilization. The content of volatiles in the polymerization reaction products can be as high as 80% or more. Whether they can be completely removed not only affects the quality of the polymer material, but is also the main source of energy consumption.

[0003] The devolatilization of polymers is a complex process. According to the research of Ramon.J.Albalak et al., the devolatilization process in most cases follows the foaming mechanism, that is, bubbles containing volatiles are formed in the polymer melt and removed. The difficulty is that with the removal of volatiles, the viscosity of the polymerization system will increase rapidly, and the difficulty of removal will also increase. The traditional method is to devolatilize by direct physical evaporation. The advantage of strengthening the devolatilization by increasing the operating temperature is that the operation is simple and easy to implement. The disadvantage is that when the volatiles reach a lower content, the volatiles are dissolved and wrapped in the polymer, which is difficult to completely remove. Too high a devolatilization temperature will also lead to an increase in the thermal degradation of the polymer, thereby causing the product performance to deteriorate. In actual production, the devolatilization effect is mainly improved from two aspects: the devolatilization process and the devolatilization equipment.

[0004] CN219110851U discloses a system for devolatilization of medium and low viscosity polymers, wherein the polymer is first preheated, enters a degassing tank to enhance bubble diffusion, and then is combined with a short-range distiller to finally remove under vacuum, but this method is only applicable to low viscosity polymer systems, and the working conditions with low volatile content. CN109646975A discloses a devolatilization device, which is composed of functions such as a feed distributor, heating, strip devolatilization and falling film devolatilization, and can complete efficient devolatilization at a suitable temperature, but is not applicable to high viscosity polymer systems, and simultaneously due to the complex structure of the equipment, long-term operation is prone to cause coking and clogging inside the evaporator, and the maintenance difficulty is large. Prior art, in order to remove volatiles to the greatest extent, often sets a multi-stage evaporator, and the devolatilization device structure is complex and expensive, not only the devolatilization efficiency is low under the working conditions of low concentration volatiles, but also causes excessive energy consumption, and does not consider the reuse of volatiles. Therefore, it is of great significance to design a device and method with simple process, high efficiency and low devolatilization limit to ensure stable quality of polymer products, reduce losses in the devolatilization process and reduce production costs. Utility Model Content

[0005] The purpose of the utility model is to provide a polymer volatile matter removal and recovery device in order to overcome the defects of the prior art.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] The technical solution of the utility model is to provide a polymer volatile matter removal and recovery device, comprising a primary positive pressure evaporation unit, a secondary vacuum extraction unit, and a volatile matter recovery unit.

[0008] Among them, the first-stage positive pressure evaporation unit includes a rising film preheating evaporator, a flash separation mechanism, and a falling film evaporator:

[0009] The rising film preheating evaporator comprises a first inlet end for introducing a volatile polymer, a second inlet end connected to the secondary vacuum extraction unit, a first outlet end connected to the flash separation mechanism, and a second outlet end for flowing out a devolatilized polymer, the first inlet end is connected to the first outlet end through a first heat exchange side, the second inlet end is connected to the second outlet end through a second heat exchange side, and the first heat exchange side is connected to the second heat exchange side for heat exchange;

[0010] The flash separation mechanism comprises a flash tank and a flash gas-liquid separation module: the flash tank comprises a first inlet end connected to the first outlet end of the rising film preheating evaporator, a first outlet end and a second inlet end connected to the flash gas-liquid separation module, and a second outlet end and a third inlet end connected to the falling film evaporator; the flash gas-liquid separation module comprises an inlet end connected to the first outlet end of the flash tank, a liquid phase outlet end connected to the second inlet end of the flash tank, and a gas phase outlet end connected to the volatile recovery unit;

[0011] The falling film evaporator comprises an inlet end connected to the second outlet end of the flash tank, and an outlet end connected to the secondary vacuum extraction unit and the third inlet end of the flash tank;

[0012] The secondary vacuum extraction unit includes a feed heater, a stripping tower and a stripping tower gas-liquid separation module:

[0013] The feed heater comprises an inlet end connected to the outlet end of the falling film evaporator and an outlet end connected to the stripping tower;

[0014] The stripping tower comprises a first inlet end connected to the outlet end of the feed heater, a second inlet end and a gas phase outlet end connected to the gas-liquid separation module of the stripping tower, and a bottom liquid phase outlet end connected to the second inlet end of the rising film preheating evaporator for heat recovery;

[0015] The gas stripping tower gas-liquid separation module includes an inlet end connected to the gas stripping tower gas phase outlet end, a gas phase outlet end connected to the volatile recovery unit, and a liquid phase outlet end connected to the second inlet end of the gas stripping tower for heat recovery;

[0016] The volatile recovery unit includes a volatile recovery tower, a gas phase volatile recovery module, a high-purity element or solvent collection module, a heavy component impurity collection module, and a volatile recovery reboiling module:

[0017] The volatile recovery tower includes a first inlet end connected to the gas phase outlet end of the flash gas-liquid separation module, a second inlet end connected to the gas phase outlet end of the gas stripping tower gas-liquid separation module, a tower top gas phase outlet end and a third inlet end connected to the gas phase volatile recovery module, a tower mid-outlet end connected to the high-purity element or solvent collection module, a tower bottom first outlet end and a fourth inlet end connected to the volatile recovery reboiler module, and a tower bottom second outlet end connected to the heavy component impurity collection module.

[0018] In some specific embodiments, the rising film preheating evaporator comprises a plurality of tubes for heating and vaporizing the polymer containing volatile components, wherein a packing assembly having the same length as the tubes and used for improving the bubbling efficiency and mass transfer area is provided in the tubes;

[0019] A flash filling section is provided on the top of the flash tank, and the first inlet end and the first outlet end of the flash tank are both located above the flash filling section;

[0020] The stripping tower is provided with a stripping filling section, the first inlet end and the second inlet end of the stripping tower are both located above the stripping filling section, and the stripping tower is provided with a stripping medium inlet below the stripping filling section.

[0021] As a more preferred embodiment, the outer diameter of the tube array ranges from 19 to 57 mm, the length of the tube array ranges from 2 to 10 m, and the filler components in the tube array may include a static mixer, a spiral belt, a spiral coil, a patterned internal part, etc.

[0022] The rising film preheating evaporator may also be a shell and tube heat exchanger, and its aspect ratio range is (1-20):1, more preferably (2-15):1.

[0023] More preferably, the flash packing section in the flash tank can be random packing or structured packing, wherein random packing such as ball rings, Raschig rings, etc. and structured packing such as sulzer structured wire mesh packing are selected.

[0024] In some specific embodiments, the flash gas-liquid separation module comprises a flash tank gas phase countercurrent condenser and a cyclone separator:

[0025] The flash tank gas phase countercurrent condenser comprises an inlet end connected to the first outlet end of the flash tank and an outlet end connected to the cyclone separator;

[0026] The cyclone separator comprises an inlet end connected to the outlet end of the flash tank gas phase countercurrent condenser, a top gas phase outlet end connected to the volatile recovery tower, and a bottom liquid phase outlet end connected to the second inlet end of the flash tank.

[0027] In some specific embodiments, the stripping tower gas-liquid separation module includes a stripping tower top gas phase condenser and a stripping tower top gas-liquid separation tank:

[0028] The gas stripping tower top gas phase condenser comprises an inlet end connected to the gas stripping tower top gas phase outlet end, and an outlet end connected to the gas-liquid separation tank at the top of the gas stripping tower;

[0029] The gas-liquid separation tank at the top of the gas stripping tower comprises an inlet end connected to the outlet end of the gas phase condenser at the top of the gas stripping tower, a top gas phase outlet end connected to the volatile recovery tower, and a bottom liquid phase outlet end connected to the second inlet end of the gas stripping tower.

[0030] In some specific embodiments, a volatile vacuum collection module is further provided between the top gas phase outlet end of the gas-liquid separation tank at the top of the gas stripping tower and the volatile recovery tower, and the volatile vacuum collection module includes a cryogenic medium heat exchanger, a volatile collection tank, and a vacuum pump group:

[0031] The cryogenic medium heat exchanger comprises an inlet end connected to the gas phase outlet end at the top of the gas-liquid separation tank at the top of the gas stripping tower, and an outlet end connected to the volatile component collection tank;

[0032] The volatile component collecting tank comprises an inlet end connected to the outlet end of the cryogenic medium heat exchanger, a top gas phase outlet end connected to the vacuum pump group, and a bottom liquid phase outlet end connected to the volatile component recovery tower.

[0033] In some specific embodiments, a volatile matter delivery pump is further provided at the liquid phase outlet end at the bottom of the volatile matter collection tank.

[0034] In some specific embodiments, the liquid phase outlet end of the gas stripping tower kettle is also connected to the inlet end of the feed heater to form a gas stripping circulation loop.

[0035] In some specific embodiments, the gas phase volatile recovery module includes a volatile recovery tower top condenser and a volatile recovery tower reflux tank:

[0036] The volatile recovery tower top condenser comprises an inlet end connected to the volatile recovery tower top gas phase outlet end, and an outlet end connected to the volatile recovery tower reflux tank;

[0037] The volatile recovery tower reflux tank comprises an inlet end connected to the outlet end of the condenser at the top of the volatile recovery tower, and an outlet end connected to the third inlet end of the volatile recovery tower for circulation recovery;

[0038] The high-purity monomer or solvent collection module includes a high-purity monomer or solvent condenser, and the high-purity monomer or solvent condenser includes an inlet end connected to the outlet end of the volatile recovery tower and an outlet end for flowing out the high-purity monomer solvent;

[0039] The volatile recovery reboiler module comprises a volatile recovery tower reboiler, wherein the volatile recovery tower reboiler comprises an inlet end connected to the first outlet end of the volatile recovery tower kettle, and an outlet end connected to the fourth inlet end of the volatile recovery tower;

[0040] The heavy component impurity collection module comprises a heavy component condenser, and the heavy component condenser comprises an inlet end connected with the second outlet end of the kettle of the volatile component recovery tower, and an outlet end for flowing out the heavy component impurities.

[0041] In some specific embodiments, a volatile recovery tower reflux pump is further provided at the outlet end of the volatile recovery tower reflux tank;

[0042] The outlet end of the volatile recovery tower is also provided with a high-purity monomer or solvent pump;

[0043] A recombinant pump is also provided at the second outlet end of the kettle of the volatile recovery tower.

[0044] In some specific embodiments, a falling film evaporator feed pump is also provided at the second outlet end of the flash tank;

[0045] The outlet of the falling film evaporator is also provided with a gas stripping tower feeding pump;

[0046] A polymer delivery pump is also provided at the liquid phase outlet end of the gas stripping tower kettle.

[0047] Compared with the prior art, the utility model has the following beneficial effects:

[0048] (1) The utility model improves the distribution of fluid on the wall of the tube by adding a packing component to the tube through the design of the rising film preheating evaporator, and can also increase the contact between the droplets and the highest steam temperature to maintain the film turbulence, thereby enhancing the foaming efficiency and mass transfer area during the evaporation process, and solves the problem that in the polymer system, as the volatile content decreases, the mass transfer of volatiles in the two-phase diffusion is limited, so that the tube always maintains a high foaming efficiency and diffusion rate. The instant flash separation of volatiles in the flash separation stage of positive pressure evaporation is realized, and more than 90 wt% of volatiles can be removed efficiently, with low energy consumption, simple process, and no need for complex evaporation equipment.

[0049] (2) The utility model adopts a vacuum extraction method to remove low-concentration volatiles from polymer species, making full use of waste heat. Under the premise of not increasing energy consumption, it can not only reduce the volatile content to below 0.1 wt%, but also effectively reduce the evaporation temperature, thus avoiding the problem of repeated high-temperature heating of the polymer during the evaporation process, which leads to increased color value, increased side reactions, poor product quality, etc. The utility model is suitable for heat-sensitive polymer systems.

[0050] (3) The utility model can purify the removed volatile components by distillation, and the monomers or solvents therein can be recycled after purification, thereby reducing raw material consumption and effectively reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a structural schematic diagram of the utility model.

[0052] The following are marked in the figure:

[0053] 1 is a rising film preheating evaporator, 2 is a flash tank, 3 is a flash tank gas phase countercurrent condenser, 4 is a cyclone separator, 5 is a falling film evaporator feed pump, 6 is a falling film evaporator, 7 is a gas stripping tower feed pump, 8 is a feed heater, 9 is a gas stripping tower top gas phase condenser, 10 is a gas stripping tower top gas-liquid separation tank, 11 is a gas stripping tower, 12 is a polymer delivery pump, 13 is a cryogenic medium heat exchanger, 14 is a volatile matter collection tank, 15 is a volatile matter delivery pump, 16 is a volatile matter recovery tower top condenser, 17 is a volatile matter recovery tower top condenser, 18 is a volatile matter recovery tower top condenser, 19 is a volatile matter recovery tower top condenser, 20 is a volatile matter recovery tower top condenser, 21 is a volatile matter recovery tower top condenser, 22 is a volatile matter recovery tower top condenser, 23 is a volatile matter recovery tower top condenser, 24 is a volatile matter recovery tower top condenser, 25 is a volatile matter recovery tower top condenser, 26 is a volatile matter recovery tower top condenser, 27 is a volatile matter recovery tower top condenser, 28 is a volatile matter recovery tower top condenser, 29 is a volatile matter recovery tower top condenser, 30 is a volatile matter recovery tower top condenser, 31 is a volatile matter recovery tower top condenser, 32 is a volatile matter recovery tower top condenser, 33 is a volatile matter recovery tower top condenser, 34 is a volatile matter recovery tower top condenser, 35 is a volatile matter recovery tower top condenser, 36 is a volatile matter recovery tower top condenser, 37 is a volatile matter recovery tower top condenser, 38 is a volatile matter recovery The volatile component recovery tower reflux tank, 18 is the volatile component recovery tower reflux pump, 19 is the volatile component recovery tower, 20 is the high-purity monomer or solvent pump, 21 is the high-purity monomer or solvent condenser, 22 is the volatile component recovery tower reboiler, 23 is the heavy component pump, 24 is the heavy component condenser, 25 is the flash gas-liquid separation module, 26 is the gas-liquid separation module of the gas stripping tower, 27 is the volatile component vacuum collection module, 28 is the gas phase volatile component recovery module, 29 is the high-purity single substance or solvent collection module, and 30 is the heavy component impurity collection module. DETAILED DESCRIPTION

[0054] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0055] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0056] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0057] In the following embodiments, unless otherwise specified, functional components or structures are conventional components or conventional structures used in the art to achieve corresponding functions.

[0058] Example 1

[0059] like Figure 1 As shown, a polymer volatile matter removal and recovery device includes three parts: a primary positive pressure evaporation unit, a secondary vacuum extraction unit, and a volatile matter recovery unit.

[0060] The first-stage positive pressure evaporation unit performs evaporation under the condition of high volatile content, reducing the volatile content from 80wt% to below 10wt%.

[0061] The secondary vacuum extraction unit is used to finally remove the polymer system with a volatile content below 10wt%, reducing the volatile content to below 0.1wt%.

[0062] The volatile matter recovery unit recovers the volatile matters evaporated from the first two stages, including monomers or solvents and other impurities.

[0063] The first part is a positive pressure evaporation unit:

[0064] The primary positive pressure evaporation unit comprises a rising film preheating evaporator 1, a flash separation mechanism, and a falling film evaporator 6:

[0065] The rising film preheating evaporator 1 includes a first inlet end for introducing a volatile polymer, a second inlet end connected to the secondary vacuum extraction unit, a first outlet end connected to the flash separation mechanism, and a second outlet end for flowing out a devolatilized polymer, wherein the first inlet end is connected to the first outlet end through a first heat exchange side, the second inlet end is connected to the second outlet end through a second heat exchange side, and the first heat exchange side is heat exchange connected to the second heat exchange side. The rising film preheating evaporator 1 includes a plurality of tubes for heating and vaporizing a volatile polymer, wherein a packing assembly having the same length as the tubes and used to improve the bubbling efficiency and mass transfer area is provided in the tubes. Exemplarily, the rising film preheating evaporator 1 is a shell and tube heat exchanger, wherein the outer diameter of the tubes ranges from 19 to 57 mm, the length of the tubes ranges from 2 to 10 m, and the aspect ratio ranges from (1 to 20):1, preferably (2 to 15):1. The packing components filled inside the tubes may include spiral twisted ribbons, static mixers, spiral coils, patterned internals, etc., to increase the foaming rate and mass transfer area in the tubes.

[0066] The flash separation mechanism includes a flash tank 2 and a flash gas-liquid separation module 25:

[0067] The flash tank 2 includes a first inlet end connected to the first outlet end of the rising film preheating evaporator 1, a first outlet end and a second inlet end connected to the flash gas-liquid separation module 25, and a second outlet end and a third inlet end connected to the falling film evaporator 6. More preferably, the second outlet end of the flash tank 2 is also provided with a falling film evaporator feed pump 5, and is connected to the falling film evaporator 6 through the falling film evaporator feed pump 5. A flash packing section is provided at the top of the flash tank 2, and the first inlet end and the first outlet end of the flash tank 2 are both located above the flash packing section. Exemplarily, the flash packing section can be selected as random packing or structured packing, and random packing such as ball rings, Raschig rings, etc. are selected, and structured packing such as sulzer structured wire mesh packing is selected.

[0068] The flash gas-liquid separation module 25 includes an inlet end connected to the first outlet end of the flash tank 2, a liquid phase outlet end connected to the second inlet end of the flash tank 2, and a gas phase outlet end connected to the volatile recovery unit. More specifically, the flash gas-liquid separation module 25 includes a flash tank gas-phase countercurrent condenser 3 and a cyclone separator 4: the flash tank gas-phase countercurrent condenser 3 includes an inlet end connected to the first outlet end of the flash tank 2 and an outlet end connected to the cyclone separator 4; the cyclone separator 4 includes an inlet end connected to the outlet end of the flash tank gas-phase countercurrent condenser 3, a top gas phase outlet end connected to the volatile recovery unit, and a bottom liquid phase outlet end connected to the second inlet end of the flash tank 2. Exemplarily, the cyclone separator 4 is a cyclone separator with a pressure drop of less than 1 kPa.

[0069] The falling film evaporator 6 includes an inlet end connected to the second outlet end of the flash tank 2, and an outlet end connected to the secondary vacuum extraction unit and the third inlet end of the flash tank 2. The outlet end of the falling film evaporator 6 is connected to the third inlet end of the flash tank 2 to form an evaporation circulation loop. In this evaporation circulation loop, the volatile content of the circulating liquid in the flash tank 2 is not more than 10wt%, more preferably ≤6wt%, and the mass ratio of the circulation amount to the feed amount is (50~1):1, preferably (30~10):1. In addition, a stripping tower feeding pump 7 is also provided at the outlet end of the falling film evaporator 6, and is respectively connected to the third inlet end of the flash tank 2 and the secondary vacuum extraction unit through the stripping tower feeding pump 7.

[0070] The second part is the secondary vacuum extraction unit:

[0071] The secondary vacuum extraction unit includes a feed heater 8, a stripping tower 11 and a stripping tower gas-liquid separation module 26:

[0072] The feed heater 8 includes an inlet end connected to the outlet end of the falling film evaporator 6 and an outlet end connected to the stripping tower 11 .

[0073] The stripping tower 11 includes a first inlet end connected to the outlet end of the feed heater 8, a second inlet end and a gas phase outlet end connected to the gas-liquid separation module 26 of the stripping tower, and a bottom liquid phase outlet end connected to the second inlet end of the rising film preheating evaporator 1 for heat recovery. In this heat recovery, the volatile content of the circulating liquid does not exceed 1wt%, more preferably ≤0.1wt%, and the mass ratio of the circulating amount to the feed amount is (20~1):1, preferably (10~5):1. Exemplarily, the stripping tower 11 is a packed tower, which is provided with a stripping packing section, the first inlet end and the second inlet end of the stripping tower 11 are both located above the stripping packing section, and the stripping tower 11 is provided with a stripping medium inlet below the stripping packing section. The stripping medium is selected from an inert gas such as nitrogen, argon, etc., and the stripping medium is first heated and then enters the stripping tower 11 from the stripping medium inlet. The bottom liquid phase outlet end of the stripping tower 11 is also connected to the inlet end of the feed heater 8 to form a stripping circulation loop. In addition, a polymer delivery pump 12 is provided at the liquid phase outlet of the bottom of the stripping tower 11, and is connected to the second inlet end of the rising film preheating evaporator 1 and the inlet end of the feed heater 8 respectively through the polymer delivery pump 12.

[0074] The gas-liquid separation module 26 of the gas stripping tower includes an inlet end connected to the gas phase outlet end of the top of the gas stripping tower 11, a gas phase outlet end connected to the volatile recovery unit, and a liquid phase outlet end connected to the second inlet end of the gas stripping tower 11 for heat recovery. More specifically, the gas stripping tower gas-liquid separation module 26 includes a gas stripping tower top gas phase condenser 9 and a gas stripping tower top gas-liquid separation tank 10: the gas stripping tower top gas phase condenser 9 includes an inlet end connected to the gas phase outlet end of the top of the gas stripping tower 11, and an outlet end connected to the gas stripping tower top gas-liquid separation tank 10; the gas stripping tower top gas-liquid separation tank 10 includes an inlet end connected to the outlet end of the gas stripping tower top gas phase condenser 9, a top gas phase outlet end connected to the volatile recovery unit, and a bottom liquid phase outlet end connected to the second inlet end of the gas stripping tower 11.

[0075] A volatile vacuum collection module 27 is also provided between the top gas phase outlet of the gas-liquid separation tank 10 at the top of the gas stripping tower and the volatile recovery unit. The volatile vacuum collection module 27 includes a cryogenic medium heat exchanger 13, a volatile collection tank 14, and a vacuum pump group: the cryogenic medium heat exchanger 13 includes an inlet end connected to the top gas phase outlet of the gas-liquid separation tank 10 at the top of the gas stripping tower, and an outlet end connected to the volatile collection tank 14; the volatile collection tank 14 includes an inlet end connected to the outlet of the cryogenic medium heat exchanger 13, a top gas phase outlet end connected to the vacuum pump group, and a bottom liquid phase outlet end connected to the volatile recovery unit. As a more preferred embodiment, a volatile delivery pump 15 is also provided at the bottom liquid phase outlet of the volatile collection tank 14, and is connected to the volatile recovery unit through the volatile delivery pump 15.

[0076] The third part is the volatile matter recovery unit:

[0077] The volatile recovery unit includes a volatile recovery tower 19, a gas phase volatile recovery module 28, a high purity element or solvent collection module 29, a heavy component impurity collection module 30, and a volatile recovery reboiling module:

[0078] The volatile recovery tower 19 includes a first inlet end connected to the gas phase outlet end at the top of the cyclone separator 4, a second inlet end connected to the liquid phase outlet end at the bottom of the volatile collection tank 14, a tower top gas phase outlet end and a third inlet end connected to the gas phase volatile recovery module 28, a tower middle outlet end connected to the high purity element or solvent collection module 29, a tower bottom first outlet end and a fourth inlet end connected to the volatile recovery reboiler module, and a tower bottom second outlet end connected to the heavy component impurity collection module 30. Exemplarily, the volatile recovery tower 19 is a plate tower, and the removed volatiles are distilled and recovered.

[0079] The gas phase volatile recovery module 28 includes a volatile recovery tower top condenser 16 and a volatile recovery tower reflux tank 17: the volatile recovery tower top condenser 16 includes an inlet end connected to the gas phase outlet end of the top of the volatile recovery tower 19 and an outlet end connected to the volatile recovery tower reflux tank 17; the volatile recovery tower reflux tank 17 includes an inlet end connected to the outlet end of the volatile recovery tower top condenser 16 and an outlet end connected to the third inlet end of the volatile recovery tower 19 for circulation recovery. More preferably, a volatile recovery tower reflux pump 18 is also provided at the outlet end of the volatile recovery tower reflux tank 17, and is connected to the third inlet end of the volatile recovery tower 19 through the volatile recovery tower reflux pump 18.

[0080] The high-purity monomer or solvent collection module 29 includes a high-purity monomer or solvent condenser 21, and the high-purity monomer or solvent condenser 21 includes an inlet end connected to the outlet end of the volatile recovery tower 19 and an outlet end for flowing out the high-purity monomer solvent. Preferably, a high-purity monomer or solvent pump 20 is also provided at the outlet end of the volatile recovery tower 19, and is connected to the inlet end of the high-purity monomer or solvent condenser 21 through the high-purity monomer or solvent pump 20.

[0081] The volatile recovery reboiler module includes a volatile recovery tower reboiler 22, and the volatile recovery tower reboiler 22 includes an inlet end connected to the first outlet end of the tower kettle of the volatile recovery tower 19, and an outlet end connected to the fourth inlet end of the volatile recovery tower 19.

[0082] The heavy component impurity collection module 30 includes a heavy component condenser 24, and the heavy component condenser 24 includes an inlet end connected to the outlet end of the tower kettle of the volatile component recovery tower 19 and an outlet end for flowing out the heavy component impurities. Preferably, a heavy component pump 23 is further provided at the second outlet end of the tower kettle of the volatile component recovery tower 19, and is connected to the inlet end of the heavy component condenser 24 through the heavy component pump 23.

[0083] In this embodiment, a method for removing volatile components such as monomers and solvents from a polymer and recovering the volatile components based on the above-mentioned polymer volatile component removal and recovery device is also provided, comprising the following steps:

[0084] First, the polymer stream containing volatile components such as monomers or solvents is preheated by a rising film preheating evaporator 1, and the preheated polymer stream enters a flash tank 2. The preheating temperature range is 70-150°C, preferably 90-120°C.

[0085] Second, in the flash tank 2, the polymer solution is immediately evaporated and separated, and the evaporated volatiles such as monomers or solvents are immediately separated from the polymer system in the form of gas phase. In the process of leaving the flash tank 2, they are initially stripped with the feed raw materials, and carry part of the volatiles into the flash tank gas phase countercurrent condenser 3 and cyclone separator 4 for treatment, and flow out from the cyclone separator 4 in the form of gas phase to the volatile recovery tower 19. In this process, the pressure in the flash tank 2 is controlled at 0.1-0.5 MPa, preferably 0.15~0.3 MPa.

[0086] Third, the polymer in the flash tank 2 is sent to the high-efficiency falling film evaporator 6 through the falling film evaporator feed pump 5, and the volatile components such as monomers or solvents are removed again. The temperature of the falling film evaporator 6 is controlled at 150-250°C, preferably 160-180°C.

[0087] Fourth, after positive pressure evaporation, the volatile content in the polymer solution is reduced to less than 10%, and the polymer material is then sent to the stripping tower 11 by the stripping tower feed pump 7, and at the same time returned to the flash tank 2 through the evaporation circulation path, so that the volatile content of the circulating liquid in the flash tank 2 is always below 10 wt%, preferably below 6 wt%. In this evaporation circulation loop, the mass ratio of the circulation amount to the feed amount is 50~1:1, preferably 30~10:1.

[0088] The stripping tower 11 is a medium vacuum packed tower, and the stripping medium adopts inert gas, including nitrogen, argon, etc. The stripping medium is heated to 165°C and enters the stripping tower 11 from the bottom of the packing. The pressure in the stripping tower 11 is controlled at 0.001-0.09 MPa, preferably 0.005~0.08 MPa. After being treated by the stripping tower 11, the volatile components such as monomers, solvents and the stripping medium are treated by the gas phase condenser 9 at the top of the stripping tower and the gas-liquid separation tank 10 at the top of the stripping tower, and then flow out from the top of the gas-liquid separation tank 10 at the top of the stripping tower to the cryogenic medium heat exchanger 13 in the form of gas phase, and the stripping medium gas stripping and liquid monomers or solvents are separated after heat exchange with the cryogenic medium, and the liquid monomers or solvents are collected in the volatile collection tank 14, and finally the liquid monomers or solvents are sent to the volatile recovery tower 19, and the gas phase outlet at the top of the volatile collection tank 14 is connected to the vacuum pump group to provide a vacuum environment for the entire secondary vacuum extraction unit.

[0089] Fifth, the volatile content of the polymer material after the stripping process is reduced to less than 0.1wt%, and is sent to the rising film preheating evaporator 1 for heat recovery. The mass ratio between the circulation amount and the feed amount between the stripping tower 11 and the rising film preheating evaporator 1 is (20-1):1, preferably (10-5):1.

[0090] Sixth, the gas phase separated by the cyclone separator 4 and the liquid phase of the volatile collection tank 14 are processed by the volatile recovery tower 19. The volatile recovery tower 19 is a plate-type atmospheric pressure tower with an operating pressure of 1kPaG~100kPaG. The gas phase enters the volatile recovery tower reflux tank 17 after condensation by the volatile recovery tower top condenser 16. Part of it is refluxed and enters the volatile recovery tower 19 again, and part of it is sent out for processing. The volatile recovery tower reboiler 22 is heated by low-pressure steam to provide weight to the volatile recovery tower 19. The part containing heavy component impurities flows out through the second outlet end of the tower kettle of the volatile recovery tower 19, and after being processed by the heavy component condenser 24, the heavy component impurities flow out. The part containing high-purity monomers or solvents flows out through the outlet of the volatile recovery tower 19, and after being processed by the high-purity monomer or solvent condenser 21, the high-purity monomers or solvents flow out.

[0091] Example 2

[0092] Based on the polymer volatile matter removal and recovery device provided in Example 1, this example provides a specific method for treating a polymer solution containing polytetrahydrofuran-methanol (purchased from Xinjiang Guotai Xinhua Chemical Co., Ltd.).

[0093] First, a 62% wt polytetrahydrofuran-methanol polymer solution is fed into a rising film preheating evaporator 1 through a polymer solution feed pipeline and preheated to 110°C.

[0094] The rising film preheating evaporator 1 adopts: the tube size is 38*6000*2 mm (outer diameter*length*thickness), the tube is filled with patterned internals (purchased from CAlGAVIN, UK), and each tube is filled with a patterned internal.

[0095] Next, it enters the flash tank 2 for flash evaporation. There is no heat input to the flash tank 2. Even if the flash evaporation is separated immediately, the operating pressure is 0.18 MPa. The gas phase volatiles flashed out are separated by the flash tank gas phase countercurrent condenser 3 and the cyclone separator 4, and the gas phase enters the volatile recovery tower 19. The liquid phase enters the flash tank 2 for flash evaporation again, which can reduce the solvent content of the flash tank 2.

[0096] Next, the polymer treated by the flash tank 2 enters the falling film evaporator 6, and the falling film evaporator 6 heats the polymer to 165°C before entering the flash tank 2. The mass ratio of the circulation amount of the positive pressure evaporation to the feed amount is 20:1, and the volatile content of the circulating liquid in the flash tank 2 is 8wt%.

[0097] Next, the polymer with a volatile content of 8 wt% after falling film evaporation treatment is preheated to 165°C by a feed heater 8 and enters the stripping tower 11 from the top. Nitrogen is used as the stripping medium and the nitrogen is heated to an operating pressure of 80 kPa. The polymer after stripping flows out from the bottom of the stripping tower 11 to the rising film preheating evaporator 1 for heat recovery. In this heat recovery, the mass ratio of the circulation amount to the feed amount is 10:1, and the volatile content of the gas circulating liquid is 0.08 wt% of the polymer.

[0098] Next, the volatiles removed from the top of the stripping tower 11 are processed by the gas phase condenser 9 at the top of the stripping tower and the gas-liquid separation tank 10 at the top of the stripping tower. The separated gas phase is heat exchanged by the cryogenic medium heat exchanger 13 and enters the volatile collection tank 14, and the liquid phase returns to the stripping tower 11. The liquid phase in the volatile collection tank 14 is also sent to the volatile recovery tower 19 for further processing, and the gas phase is connected to the vacuum pump group to provide a vacuum environment for the entire secondary vacuum extraction unit.

[0099] Next, in the volatile recovery tower 19, the removed volatiles are distilled and purified. The volatile recovery tower 19 is a normal pressure plate tower with an operating pressure of 5±0.5 kPaG, an operating temperature of 90°C±1, and 20 trays. The gas phase is condensed by the volatile recovery tower top condenser 16 and enters the volatile recovery tower reflux tank 17. Part of it is refluxed to the volatile recovery tower 19, and part of it is sent out for treatment. The volatile recovery tower reboiler 22 is heated by low-pressure steam to provide weight to the volatile recovery tower 19. The part containing heavy component impurities flows out through the second outlet end of the tower kettle of the volatile recovery tower 19, and after being treated by the heavy component condenser 24, the heavy component impurities flow out. The part containing high-purity monomers or solvents flows out through the outlet of the volatile recovery tower 19, and after being treated by the high-purity monomer or solvent condenser 21, the high-purity monomers or solvents flow out.

[0100] The above description of the embodiments is to facilitate the understanding and use of the utility model by those skilled in the art. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the utility model is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the utility model without departing from the scope of the utility model should be within the scope of protection of the utility model.

Claims

1. A polymer volatile matter removal and recovery device, characterized in that: It includes a primary positive pressure evaporation unit, a secondary vacuum extraction unit, and a volatile matter recovery unit. The first-stage positive pressure evaporation unit includes a rising film preheating evaporator (1), a flash separation mechanism, and a falling film evaporator (6): The rising film preheating evaporator (1) comprises a first inlet end for introducing a volatile polymer, a second inlet end connected to the secondary vacuum extraction unit, a first outlet end connected to the flash separation mechanism, and a second outlet end for discharging a devolatilized polymer, wherein the first inlet end is connected to the first outlet end via a first heat exchange side, the second inlet end is connected to the second outlet end via a second heat exchange side, and the first heat exchange side is connected to the second heat exchange side for heat exchange; The flash separation mechanism comprises a flash tank (2) and a flash gas-liquid separation module (25): the flash tank (2) comprises a first inlet end connected to the first outlet end of the rising film preheating evaporator (1), a first outlet end and a second inlet end connected to the flash gas-liquid separation module (25), and a second outlet end and a third inlet end connected to the falling film evaporator (6); the flash gas-liquid separation module (25) comprises an inlet end connected to the first outlet end of the flash tank (2), a liquid phase outlet end connected to the second inlet end of the flash tank (2), and a gas phase outlet end connected to the volatile matter recovery unit; The falling film evaporator (6) comprises an inlet end connected to the second outlet end of the flash tank (2), and an outlet end connected to the secondary vacuum extraction unit and the third inlet end of the flash tank (2); The secondary vacuum extraction unit comprises a feed heater (8), a stripping tower (11) and a stripping tower gas-liquid separation module (26): The feed heater (8) comprises an inlet end connected to the outlet end of the falling film evaporator (6) and an outlet end connected to the stripping tower (11); The stripping tower (11) comprises a first inlet end connected to the outlet end of the feed heater (8), a second inlet end and a gas phase outlet end connected to the gas-liquid separation module (26) of the stripping tower, and a bottom liquid phase outlet end connected to the second inlet end of the rising film preheating evaporator (1) for heat recovery; The stripping tower gas-liquid separation module (26) comprises an inlet end connected to the gas phase outlet end of the stripping tower (11), a gas phase outlet end connected to the volatile matter recovery unit, and a liquid phase outlet end connected to the second inlet end of the stripping tower (11) for heat recovery; The volatile recovery unit comprises a volatile recovery tower (19), a gas phase volatile recovery module (28), a high purity element or solvent collection module (29), a heavy component impurity collection module (30), and a volatile recovery reboiling module: The volatile recovery tower (19) comprises a first inlet end connected to the gas phase outlet end of the flash gas-liquid separation module (25), a second inlet end connected to the gas phase outlet end of the gas stripping tower gas-liquid separation module (26), a tower top gas phase outlet end and a third inlet end connected to the gas phase volatile recovery module (28), a tower mid-outlet end connected to the high-purity element or solvent collection module (29), a tower bottom first outlet end and a fourth inlet end connected to the volatile recovery reboiler module, and a tower bottom second outlet end connected to the heavy component impurity collection module (30).

2. The polymer volatile matter removal and recovery device according to claim 1, characterized in that: The rising film preheating evaporator (1) comprises a plurality of tubes for heating and vaporizing the polymer containing volatile components, wherein a packing component having the same length as the tubes and used for improving the bubbling efficiency and mass transfer area is arranged in the tubes; A flash filling section is provided at the top of the flash tank (2), and a first inlet end and a first outlet end of the flash tank (2) are both located above the flash filling section; The stripping tower (11) is provided with a stripping filling section, the first inlet end and the second inlet end of the stripping tower (11) are both located above the stripping filling section, and the stripping tower (11) is provided with a stripping medium inlet below the stripping filling section.

3. The polymer volatile matter removal and recovery device according to claim 1, characterized in that: The flash gas-liquid separation module (25) comprises a flash tank gas phase countercurrent condenser (3) and a cyclone separator (4): The flash tank gas phase countercurrent condenser (3) comprises an inlet end connected to the first outlet end of the flash tank (2) and an outlet end connected to the cyclone separator (4); The cyclone separator (4) comprises an inlet end connected to the outlet end of the flash tank gas phase countercurrent condenser (3), a top gas phase outlet end connected to the volatile matter recovery tower (19), and a bottom liquid phase outlet end connected to the second inlet end of the flash tank (2).

4. The polymer volatile matter removal and recovery device according to claim 1, characterized in that: The stripping tower gas-liquid separation module (26) comprises a stripping tower top gas phase condenser (9) and a stripping tower top gas-liquid separation tank (10): The gas stripping tower top gas phase condenser (9) comprises an inlet end connected to the gas stripping tower top gas phase outlet end (11), and an outlet end connected to the gas-liquid separation tank (10) at the top of the gas stripping tower; The gas-liquid separation tank (10) at the top of the gas stripping tower comprises an inlet end connected to the outlet end of the gas-phase condenser (9) at the top of the gas stripping tower, a top gas-phase outlet end connected to the volatile recovery tower (19), and a bottom liquid-phase outlet end connected to the second inlet end of the gas stripping tower (11).

5. The polymer volatile matter removal and recovery device according to claim 4, characterized in that: A volatile component vacuum collection module (27) is also provided between the top gas phase outlet end of the gas-liquid separation tank (10) at the top of the gas stripping tower and the volatile component recovery tower (19). The volatile component vacuum collection module (27) comprises a cryogenic medium heat exchanger (13), a volatile component collection tank (14), and a vacuum pump group: The cryogenic medium heat exchanger (13) comprises an inlet end connected to the gas phase outlet end at the top of the gas-liquid separation tank (10) at the top of the gas stripping tower, and an outlet end connected to the volatile component collection tank (14); The volatile matter collection tank (14) comprises an inlet end connected to the outlet end of the cryogenic medium heat exchanger (13), a top gas phase outlet end connected to the vacuum pump group, and a bottom liquid phase outlet end connected to the volatile matter recovery tower (19).

6. The polymer volatile matter removal and recovery device according to claim 5, characterized in that: A volatile matter delivery pump (15) is also provided at the bottom liquid phase outlet of the volatile matter collection tank (14).

7. The polymer volatile matter removal and recovery device according to claim 1, characterized in that: The liquid phase outlet end of the bottom of the gas stripping tower (11) is also connected to the inlet end of the feed heater (8) to form a gas stripping circulation loop.

8. The polymer volatile matter removal and recovery device according to claim 1, characterized in that: The gas phase volatile recovery module (28) comprises a volatile recovery tower top condenser (16) and a volatile recovery tower reflux tank (17): The volatile recovery tower top condenser (16) comprises an inlet end connected to the gas phase outlet end of the top of the volatile recovery tower (19), and an outlet end connected to the volatile recovery tower reflux tank (17); The volatile recovery tower reflux tank (17) comprises an inlet end connected to the outlet end of the volatile recovery tower top condenser (16), and an outlet end connected to the third inlet end of the volatile recovery tower (19) for circulation recovery; The high-purity monomer or solvent collection module (29) comprises a high-purity monomer or solvent condenser (21), wherein the high-purity monomer or solvent condenser (21) comprises an inlet end connected to the outlet end of the volatile recovery tower (19), and an outlet end for flowing out the high-purity monomer solvent; The volatile recovery reboiler module comprises a volatile recovery tower reboiler (22), wherein the volatile recovery tower reboiler (22) comprises an inlet end connected to a first outlet end of a kettle of the volatile recovery tower (19), and an outlet end connected to a fourth inlet end of the volatile recovery tower (19); The heavy component impurity collection module (30) comprises a heavy component condenser (24), wherein the heavy component condenser (24) comprises an inlet end connected to the second outlet end of the bottom of the volatile component recovery tower (19), and an outlet end for flowing out the heavy component impurities.

9. The polymer volatile matter removal and recovery device according to claim 8, characterized in that: A volatile recovery tower reflux pump (18) is also provided at the outlet end of the volatile recovery tower reflux tank (17); The volatile recovery tower (19) is also provided with a high-purity monomer or solvent pump (20) at the outlet end of the tower; A recombinant component pump (23) is also provided at the second outlet end of the bottom of the volatile component recovery tower (19).

10. The polymer volatile matter removal and recovery device according to claim 1, characterized in that: A falling film evaporator feed pump (5) is also provided at the second outlet end of the flash tank (2); A stripping tower feeding pump (7) is also provided at the outlet end of the falling film evaporator (6); A polymer delivery pump (12) is also provided at the liquid phase outlet end of the bottom of the gas stripping tower (11).

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