Polypropylene process powder degassing system and its degassing process

Abstract

The present invention relates to a polypropylene process powder degassing system, comprising: a reaction discharge line and a powder degassing system connected to the reaction discharge line, wherein the powder degassing system comprises an expansion bag filter, a degassing bin, a steam tank and a drying tank connected in sequence, wherein one end of the reaction discharge line is connected to the reactor, and the other end is connected to the middle of the expansion bag filter, the bottom discharge port of the expansion bag filter is connected to the top feed port of the degassing bin through a first pipeline, the bottom discharge port of the degassing bin is connected to the top feed port of the steam tank through a second pipeline, and the bottom discharge port of the steam tank is connected to the top feed port of the drying tank through a third pipeline. The degassing effect is good, and heavy hydrocarbon impurities such as hydrocarbons, benzenes, aldehydes, and ketones in the product can be effectively removed.

Description

Technical Field

[0001] The invention relates to the technical field of polypropylene production, in particular to a polypropylene process powder degassing system and a degassing process thereof. Background Art

[0002] The finished products of polypropylene JPP process generally have a strong odor problem, which makes the products produced by this process unable to be widely used in the fields of food, medical care, high-end automotive interiors, etc., and seriously restricts the development of this process in high-end and cutting-edge fields. The main restrictive factor is that the original degassing and deactivation system cannot completely and effectively remove heavy hydrocarbon impurities such as benzene, aldehydes, and ketones in the product. Summary of the invention

[0003] In view of the deficiencies of the prior art, the object of the present invention is to provide a polypropylene process powder degassing system, which can effectively remove heavy hydrocarbon impurities such as hydrocarbons, benzenes, aldehydes, ketones, etc. in the polypropylene process powder.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A polypropylene process powder degassing system comprises: a reaction discharge line and a powder degassing system connected to the reaction discharge line, wherein the powder degassing system comprises an expansion bag filter, a degassing bin, a steam tank and a drying tank connected in sequence, wherein one end of the reaction discharge line is connected to the reactor, and the other end is connected to the middle of the expansion bag filter, the bottom discharge port of the expansion bag filter is connected to the top feed port of the degassing bin through a first pipeline, the bottom discharge port of the degassing bin is connected to the top feed port of the steam tank through a second pipeline, and the bottom discharge port of the steam tank is connected to the top feed port of the drying tank through a third pipeline.

[0006] Furthermore, it also includes a powder conveying system, the bottom discharge port of the drying tank is connected to the powder conveying system, and the powder conveying system includes a second rotary valve, a powder silo, a powder silo filter, a powder conveying nitrogen filter, a powder conveying compressor and a powder conveying nitrogen cooler, wherein the air outlet at the top of the powder silo is connected to the powder silo filter, the powder conveying nitrogen filter, the powder conveying compressor, the powder conveying nitrogen cooler and the powder inlet at the top of the powder silo in sequence through a pipeline to form a circulating gas flow channel, and the bottom discharge port of the drying tank is connected to the circulating gas flow channel through the second rotary valve.

[0007] Furthermore, it also includes a powder vibrating screen and a crusher, the bottom discharge port of the expansion bag filter is connected to the feed port of the powder vibrating screen through a first rotary valve, the qualified powder outlet of the powder vibrating screen is connected to the top feed port of the degassing bin, the unqualified powder outlet of the powder vibrating screen is connected to the feed port of the crusher, and the crusher discharge port is connected to the upper feed port of the degassing bin.

[0008] Preferably, the first rotary valve is a hydraulic rotary valve with a cutter.

[0009] Furthermore, the nitrogen inlet at the bottom of the degassing bin is connected to the first nitrogen pipeline through the first heater; the nitrogen outlet at the top of the degassing bin is connected to the membrane recovery system through the recovery gas compressor, and the nitrogen outlet of the membrane recovery system is connected to the first nitrogen pipeline to form a nitrogen circulation channel; a cooler and a first separator are sequentially arranged on the pipeline between the recovery gas compressor and the membrane recovery system; the upper outlet of the water scrubber is connected to the second separator.

[0010] Furthermore, the upper, middle and lower parts of the steam tank are respectively connected to steam pipelines; the top steam outlet of the steam tank is connected to the lower steam inlet of the water washing tower through a steam cyclone separator, and the upper exhaust port of the water washing tower is connected to the membrane recovery system through a recovery gas compressor; the upper outlet of the water washing tower is connected to the second separator.

[0011] Furthermore, a steaming agitator is provided on the steaming tank.

[0012] Furthermore, the nitrogen inlet at the bottom of the drying tank is connected to the second nitrogen pipeline through the second heater; a washing tower, an inlet buffer tank and a drying blower are sequentially arranged on the pipeline between the second heater and the second nitrogen pipeline, the second nitrogen pipeline is connected to the nitrogen inlet at the bottom of the washing tower, the top nitrogen outlet of the washing tower is connected to the lower inlet of the inlet buffer tank, the top outlet of the inlet buffer tank is connected to the inlet of the drying blower, the outlet of the drying blower is connected to the inlet of the second heater, and the outlet of the second heater is connected to the nitrogen inlet at the bottom of the drying tank; the nitrogen outlet at the top of the drying tank is connected to the nitrogen inlet of the water washing tower through a drying cyclone separator, and the bottom powder outlet of the drying cyclone separator is connected to the circulating gas flow channel through a powder collection tank.

[0013] It should be noted that the beneficial effects of the present invention compared with the prior art are:

[0014] The polypropylene process powder degassing system provided by the present invention comprises: a reaction discharge line and a powder degassing system connected to the reaction discharge line, wherein the powder degassing system comprises an expansion bag filter, a degassing bin, a steam tank and a drying tank connected in sequence, wherein one end of the reaction discharge line is connected to the reactor, and the other end is connected to the middle of the expansion bag filter, the bottom discharge port of the expansion bag filter is connected to the top feed port of the degassing bin through a first pipeline, the bottom discharge port of the degassing bin is connected to the top feed port of the steam tank through a second pipeline, and the bottom discharge port of the steam tank is connected to the top feed port of the drying tank through a third pipeline. It has a good degassing effect and can effectively remove heavy hydrocarbon impurities such as hydrocarbons, benzene, aldehydes, ketones, etc. in the product.

[0015] Another object of the present invention is to provide a degassing process of the above-mentioned polypropylene process powder degassing system, comprising the following steps:

[0016] 1) The powder discharged from the reactor is passed into the expansion bag filter through the reaction discharge line, and the pressure is suddenly reduced through the expansion bag filter, and expansion separation is achieved;

[0017] 2) After the powder is discharged into the degassing bin through the expansion bag filter, it stays in the degassing bin for more than 2 hours, and then hot nitrogen is introduced into the degassing bin, and the hot nitrogen is used to reversely purge the degassing bin for degassing;

[0018] 3) The powder is discharged into the steamer through the degassing bin, and then steam is introduced into the steamer to cook the powder at high temperature in the steamer;

[0019] 4) The powder is discharged from the steam tank into the drying tank, where the steamed wet powder is dried.

[0020] Furthermore, the method further comprises the following steps:

[0021] The powder is discharged through the expansion bag filter and enters the vibrating screen. The qualified powder screened by the vibrating screen directly enters the degassing bin, and the unqualified powder screened by the vibrating screen is discharged into the grinder. The unqualified powder is crushed into fine chips by the grinder and enters the degassing bin.

[0022] It should be noted that the beneficial effects of the degassing process of the polypropylene process powder degassing system provided by the present invention are the same as the beneficial effects of the above-mentioned polypropylene process powder degassing system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0024] In the figure: 1, reaction discharge line, 2, first pipeline, 3, second pipeline, 4, third pipeline, 5, first nitrogen pipeline, 6, membrane recovery system, 7, steam pipeline, 8, second nitrogen pipeline, 9, extrusion granulation system, 10, tail gas compression system, 11, expansion bag filter, 12, degassing bin, 13, steam tank, 14, drying tank, 15, degassing bin bag filter, 16, first heater, 17, recovery gas compressor, 18, cooler, 19, cyclone separator, 20, water washing tower, 21, steam agitator, 22, second heater, 23, Drying cyclone separator, 24, powder collecting tank, 25, second rotary valve, 26, powder silo, 27, powder silo filter, 28, powder conveying nitrogen filter, 29, powder conveying compressor, 30, powder conveying nitrogen cooler, 31, vibrating screen, 32, pulverizer, 33, first rotary valve, 34, washing tower, 35, inlet buffer tank, 36, drying blower, 37, tower bottom reflux pump, 38, second cooler, 39, degassing bin exhaust gas recovery filter, 40, first separator, 41, second separator, 42, second tower bottom reflux pump. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Example

[0026] like Figure 1 As shown, a polypropylene process powder degassing system comprises: a reaction discharge line 1 and a powder degassing system connected to the reaction discharge line 1, the powder degassing system comprises an expansion bag filter 11, a degassing bin 12, a steam tank 13 and a drying tank 14 connected in sequence, the reaction discharge line 1 is used to transport polypropylene process powder, one end of the reaction discharge line 1 is connected to the reactor, and the other end is connected to the middle of the expansion bag filter 11, the bottom discharge port of the expansion bag filter 11 is connected to the top feed port of the degassing bin 12 through a first pipeline 2, the bottom discharge port of the degassing bin 12 is connected to the top feed port of the steam tank 13 through a second pipeline 3, and the bottom discharge port of the steam tank 13 is connected to the top feed port of the drying tank 14 through a third pipeline 4.

[0027] It should be noted that the powder in the above technical solution is degassed in sequence through the expansion bag filter 11, the degassing bin 12, the steam tank 13 and the drying tank 14, and the degassing effect is good, and heavy hydrocarbon impurities such as hydrocarbons, benzene, aldehydes, ketones, etc. in the product can be effectively removed.

[0028] The present embodiment also includes a powder conveying system, the bottom discharge port of the drying tank 14 is connected to the powder conveying system, and the powder conveying system includes a second rotary valve 25, a powder bin 26, a powder bin filter 27, a powder conveying nitrogen filter 28, a powder conveying compressor 29 and a powder conveying nitrogen cooler 30, wherein the top air outlet of the powder bin 26 is connected to the powder bin filter 27, the powder conveying nitrogen filter 28, the powder conveying compressor 29, the powder conveying nitrogen cooler 30 and the powder inlet at the top of the powder bin 26 in sequence through a pipeline, and a circulating gas flow channel is formed, and the bottom discharge port of the drying tank 14 is connected to the circulating gas flow channel through the second rotary valve 25. The bottom outlet of the powder bin 26 is connected to the extrusion granulation system 9. The present embodiment includes two powder conveying compressors 29, one for standby and one for use, and specifically, the two powder conveying compressors 29 are arranged in parallel in the circulating gas flow channel. It should be noted that the powder conveying system of the present embodiment can realize the recycling of nitrogen, and the conveying efficiency is high.

[0029] The upper exhaust port of the expansion bag filter 11 of this embodiment is connected to the exhaust gas compression system 10 .

[0030] The nitrogen inlet at the bottom of the degassing bin 12 of this embodiment is connected to the first nitrogen pipeline 5 through the first heater 16. Specifically, the nitrogen outlet at the top of the degassing bin 12 is connected to the membrane recovery system 6 through the recovery gas compressor 17, and the nitrogen outlet of the membrane recovery system 6 is connected to the first nitrogen pipeline 5, and a nitrogen circulation channel is formed, which is conducive to degassing.

[0031] In this embodiment, the degassing bin bag filter 15 and the degassing bin exhaust gas filter 39 are sequentially arranged on the pipeline between the nitrogen outlet at the top of the degassing bin 12 and the recovery gas compressor, which are used to separate the fine powder entrained in the purified gas, and a metering scale is arranged at the bottom of the degassing bin 12 to weigh the weight of the powder in the bin. When in use, the powder flows evenly from top to bottom in the degassing bin 12 during the degassing process, and the hot nitrogen is reversely purged from bottom to top. The degassed powder is continuously transported downward through the V-shaped ball valve and enters the steaming tank 13.

[0032] The upper, middle and lower parts of the steam tank 13 of this embodiment are connected to the steam pipeline 7 respectively, the top steam outlet of the steam tank 13 is connected to the lower steam inlet of the water washing tower 20 through the steam cyclone separator 19, and the upper exhaust port of the water washing tower 20 is connected to the membrane recovery system 6 through the recovery gas compressor 17. The pipeline between the recovery gas compressor 17 and the membrane recovery system 6 in this embodiment is sequentially provided with a cooler 18 and a first separator 40. The upper outlet of the water washing tower 20 in this embodiment is connected to the second separator 41 for separating waste oil. A reflux pipeline is provided between the bottom outlet of the water washing tower 20 and the middle inlet of the water washing tower 20, and a second tower bottom reflux pump 42 is provided on the reflux pipeline, and the bottom outlet of the second separator 41 is connected to the inlet of the second tower bottom reflux pump 42 through a pipeline.

[0033] Preferably, the steaming tank 13 is provided with a steaming stirrer 21, the main function of which is to scrape the wall of the tank to prevent the fine powder from forming flakes on the wall of the tank, which is conducive to degassing. When in use, the steam after temperature reduction and pressure reduction in the steam pipeline 7 is added from the upper, middle and lower positions of the steaming tank 13 respectively. Under the stirring of the steaming stirrer 21, the powder in the steaming tank 13 is heated and purged by steam, and the odorous gases such as hydrocarbons, aldehydes, ketones, benzenes, heavy hydrocarbons, etc. in the powder are separated from the powder after steam heating and purging, and enter the water washing tower 20 after passing through the cyclone separator 19. After passing through the water washing tower 20, the oligomers and fine powder in the system are discharged from the water washing tower 20, and the waste oil is discharged from the second separator 41. The washed propylene gas is compressed by the recovery gas compressor 17 and then passes through the cooler 18. The condensed water is discharged from the bottom of the first separator 40, and the gas enters the inlet of the membrane recovery compressor for compression and separation. The high-purity nitrogen recovered by the membrane recovery device returns to the degassing bin 12 for cyclic degassing, and the degassing effect is good.

[0034] The nitrogen inlet at the bottom of the drying tank 14 of this embodiment is connected to the second nitrogen pipeline 8 through the second heater 22, and the pipeline between the second heater 22 and the second nitrogen pipeline 8 is sequentially provided with a washing tower 34, an inlet buffer tank 35 and a drying blower 36, so as to form a hot nitrogen circulation channel for degassing. Specifically, the second nitrogen pipeline 8 is connected to the nitrogen inlet at the bottom of the washing tower 34, the nitrogen outlet at the top of the washing tower 34 is connected to the lower inlet of the inlet buffer tank 35, the top outlet of the inlet buffer tank 35 is connected to the inlet of the drying blower 36, the outlet of the drying blower 36 is connected to the inlet of the second heater 22, and the outlet of the second heater 22 is connected to the nitrogen inlet at the bottom of the drying tank 14; the nitrogen outlet at the top of the drying tank 14 is connected to the nitrogen inlet at the bottom of the washing tower 34 through the drying cyclone separator 23, and the bottom powder outlet of the drying cyclone separator 23 is connected to the circulating gas flow channel through the powder collecting tank 24. In this embodiment, a reflux pipeline is provided between the bottom outlet of the washing tower 34 and the upper inlet of the washing tower 34 , and a bottom reflux pump 37 and a second cooler 38 are sequentially provided on the reflux pipeline.

[0035] When in use, the powder passes through the steaming tank 13 and enters the drying tank 14, where it is purged and dried by hot nitrogen circulation, and the powder is in a completely fluidized state in the drying tank 14. The dried powder passes through the second rotary valve 25 and is transported to the powder bin 26 by the powder transport compressor 29, and finally enters the extrusion granulation system 9.

[0036] In order to ensure that all irregular powders in the powder are completely separated and crushed, so that the gas phase powder can generally meet the conditions of steam drying, and avoid the irregular powder from being blocked in the steam tank 13 and the drying tank 14, the present embodiment also includes a powder vibrating screen 31 and a grinder 32, the bottom discharge port of the expansion bag filter 11 is connected to the feed port of the powder vibrating screen 31 through the first rotary valve 33, the qualified powder outlet of the powder vibrating screen 31 is connected to the top feed port of the degassing bin 12, the unqualified powder outlet of the powder vibrating screen 31 is connected to the feed port of the grinder 32, and the discharge port of the grinder 32 is connected to the upper feed port of the degassing bin 12.

[0037] Preferably, the first rotary valve 33 is a hydraulic rotary valve with a cutter. When in use, the hydraulic rotary valve can be reversed to cut off a large amount of irregular materials such as flakes, blocks, and lumps in the expansion bag filter 11, reducing the frequency of powder rotary valve stuck accidents, facilitating the smooth degassing, thereby improving the degassing efficiency.

[0038] The degassing process of the polypropylene process powder degassing system of this embodiment includes the following steps:

[0039] 1) The powder discharged from the reactor is passed into the expansion bag filter 11 through the reaction discharge line 1, and the pressure is reduced through the expansion bag filter 11, and expansion separation is achieved. It should be noted that the gas pressure drops suddenly during the discharge of the reactor powder, so that a large amount of hydrocarbons entrained in the powder are released, thereby achieving the first step of degassing the powder. After the first step, the hydrocarbons in the powder are only 2-5% w / w.

[0040] 2) After the powder is discharged into the degassing bin 12 through the expansion bag filter 11, it stays in the degassing bin 12 for more than 2 hours, and then hot nitrogen is introduced into the degassing bin 12, and the hot nitrogen is used to reversely purge the degassing bin 12 for degassing. It should be noted that the powder is degassed by reversely purge with hot nitrogen for more than 2 hours, so that the hydrocarbon content in the powder is reduced to 1000-4000ppm.

[0041] 3) The powder is discharged into the steaming tank 13 through the degassing bin 12, and then steam is introduced into the steaming tank 13 to perform high-temperature steaming on the powder in the steaming tank 13. It should be noted that the high-temperature steaming of the powder by steam can completely remove the residual odor impurities in the powder, as well as the impurities such as hydrocarbons, ketones, aldehydes, benzene, etc. generated by the deactivation reaction, and the hydrocarbon substances in the powder can be reduced to less than 100 ppm.

[0042] 4) The powder is discharged from the steaming tank 13 to the drying tank 14, and the cooked wet powder is dried in the drying tank 14. It should be noted that drying the cooked wet powder can prevent water vapor from entering the extruder to cause damage to the template, cutter, and screw, thereby improving the degassing efficiency.

[0043] It should be noted that in the above process in this embodiment, the powder is sequentially degassed by the pressure drop of the expansion bag filter 11, degassed by reverse blowing of hot nitrogen in the degassing bin 12, degassed by high-temperature steaming of the powder by steam in the steaming tank 13, and dried in the drying tank 14. The degassing effect is good, and heavy hydrocarbon impurities such as hydrocarbons, benzene, aldehydes, ketones, etc. in the product can be effectively removed.

[0044] In order to ensure that all irregular powders in the powder are completely separated and crushed, so that the gas phase powder can generally meet the conditions of steam drying, and avoid the irregular powder from being blocked in the steam tank 13 and the drying tank 14, the degassing process in one embodiment also includes screening and crushing the powder after the pressure drop, and then using hot nitrogen to reversely blow for degassing. Specifically, the powder is discharged from the expansion bag filter 11 and enters the vibrating screen 31. The qualified powder screened by the vibrating screen 31 directly enters the degassing bin 12. The unqualified powder screened by the vibrating screen 31 is discharged into the pulverizer 32. The unqualified powder is crushed into fine chips by the pulverizer 32 and enters the degassing bin 12.

[0045] It should be noted that a first rotary valve 33 is also provided between the expansion bag filter 11 and the vibrating screen 31. The powder in the expansion bag filter 11 is discharged into the vibrating screen 31 through the first rotary valve 33. Preferably, the first rotary valve 33 is a hydraulic rotary valve with a cutter. When in use, the hydraulic rotary valve can be reversed to cut off a large amount of irregular materials such as flakes, blocks, and pellets in the expansion bag filter 11, thereby reducing the frequency of accidents caused by the powder rotary valve being stuck, thereby improving the degassing efficiency.

[0046] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "one side", "top", "inside", "front", "center", "two ends" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise clearly specified and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0047] In the description of the present invention, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0048] Although the embodiments of the present invention have been shown and described above, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Polypropylene process powder degassing system, characterized by: include: A reaction discharge line and a powder degassing system connected to the reaction discharge line, wherein the powder degassing system comprises an expansion bag filter, a degassing bin, a steam tank and a drying tank connected in sequence, one end of the reaction discharge line is connected to the reactor, and the other end is connected to the middle of the expansion bag filter, the bottom discharge port of the expansion bag filter is connected to the top feed port of the degassing bin through a first pipeline, the bottom discharge port of the degassing bin is connected to the top feed port of the steam tank through a second pipeline, and the bottom discharge port of the steam tank is connected to the top feed port of the drying tank through a third pipeline; It also includes a powder conveying system, the bottom discharge port of the drying tank is connected to the powder conveying system, and the powder conveying system includes a second rotary valve, a powder bin, a powder bin filter, a powder conveying nitrogen filter, a powder conveying compressor, and a powder conveying nitrogen cooler, wherein the top gas outlet of the powder bin is sequentially connected to the powder bin filter, the powder conveying nitrogen filter, the powder conveying compressor, the powder conveying nitrogen cooler, and the powder inlet at the top of the powder bin through a pipeline, and a circulating gas flow channel is formed, and the bottom discharge port of the drying tank is connected to the circulating gas flow channel through the second rotary valve; the bottom outlet of the powder bin is connected to the extrusion granulation system, The invention also includes two powder conveying compressors, one for backup and the other for use, which are arranged in parallel in the circulating gas flow channel; the invention also includes a powder vibrating screen and a pulverizer, the bottom discharge port of the expansion bag filter is connected to the feed port of the powder vibrating screen through a first rotary valve, the qualified powder outlet of the powder vibrating screen is connected to the feed port at the top of the degassing bin, the unqualified powder outlet of the powder vibrating screen is connected to the feed port of the pulverizer, and the discharge port of the pulverizer is connected to the feed port at the top of the degassing bin; The first rotary valve is a hydraulic rotary valve with a cutter.

2. The polypropylene process powder degassing system according to claim 1, characterized in that: The nitrogen inlet at the bottom of the degassing bin is connected to the first nitrogen pipeline through the first heater; the nitrogen outlet at the top of the degassing bin is connected to the membrane recovery system through the recovery gas compressor, and the nitrogen outlet of the membrane recovery system is connected to the first nitrogen pipeline to form a nitrogen circulation channel; a cooler and a first separator are sequentially arranged on the pipeline between the recovery gas compressor and the membrane recovery system.

3. The polypropylene process powder degassing system according to claim 1, characterized in that: The upper, middle and lower parts of the steam tank are connected to steam pipelines respectively; the top steam outlet of the steam tank is connected to the lower steam inlet of the water washing tower through a steam cyclone separator, and the upper exhaust port of the water washing tower is connected to the membrane recovery system through a recovery gas compressor; the upper outlet of the water washing tower is connected to the second separator.

4. The polypropylene process powder degassing system according to claim 3, characterized in that: The steaming tank is provided with a steaming stirrer.

5. The polypropylene process powder degassing system according to claim 3, characterized in that: The nitrogen inlet at the bottom of the drying tank is connected to the second nitrogen pipeline through the second heater; a washing tower, an inlet buffer tank and a drying blower are sequentially arranged on the pipeline between the second heater and the second nitrogen pipeline, the second nitrogen pipeline is connected to the nitrogen inlet at the bottom of the washing tower, the nitrogen outlet at the top of the washing tower is connected to the lower inlet of the inlet buffer tank, the top outlet of the inlet buffer tank is connected to the inlet of the drying blower, the outlet of the drying blower is connected to the inlet of the second heater, and the outlet of the second heater is connected to the nitrogen inlet at the bottom of the drying tank; the nitrogen outlet at the top of the drying tank is connected to the nitrogen inlet of the water washing tower through a drying cyclone separator, and the bottom powder outlet of the drying cyclone separator is connected to the circulating gas flow channel through a powder collecting tank.

6. The degassing process of the polypropylene process powder degassing system according to claims 1-5, characterized in that: The following steps are involved: 1) The powder discharged from the reactor is passed into the expansion bag filter through the reaction discharge line, and the pressure is reduced through the expansion bag filter, and expansion separation is achieved; 2) After the powder is discharged into the degassing bin through the expansion bag filter, it stays in the degassing bin for more than 2 hours, and then hot nitrogen is introduced into the degassing bin, and the hot nitrogen is used to reversely purge the degassing bin for degassing; 3) The powder is discharged into the steamer through the degassing bin, and then steam is introduced into the steamer to cook the powder at high temperature in the steamer; 4) The powder is discharged from the steam tank into the drying tank, where the steamed wet powder is dried.

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