Production device and process of impact-resistant polypropylene based on dehydrogenation chamber-depropylene tower

Abstract

The present invention relates to a production device and process of impact-resistant polypropylene based on a dehydrogenation warehouse-depropylene tower, the device includes a first reactor and a second reactor sequentially arranged along the flow direction of the main material, a dehydrogenation warehouse is also provided between the first reactor and the second reactor, a depropylene tower for receiving condensate formed by condensation of the top gas phase is also provided beside the second reactor, the top outlet of the depropylene tower is also returned to connect the second reactor, and the bottom outlet is also returned to connect the dehydrogenation warehouse. The present invention adopts a combined process of a dehydrogenation warehouse and a depropylene tower, effectively solving the problem of excess hydrogen and propylene, not only the operation process is simple (continuous operation, no need for an air lock system), but also the energy consumption of the device is reduced, and it can be used for the production of high-quality, full-grade (including homopolymers, random copolymers, impact copolymers, terpolymers) polypropylene powders and pellets.

Description

Technical Field

[0001] The invention belongs to the technical field of polypropylene production, and relates to a production device and process of impact-resistant polypropylene based on a dehydrogenation bin-depropylene tower. Background Art

[0002] Polypropylene is a thermoplastic synthetic resin with excellent performance generated by the polymerization reaction of propylene monomer under the action of a catalyst. Polypropylene has good properties such as non-toxicity, chemical resistance, low relative density, heat resistance, and easy processing and molding. It can be processed into woven products, injection molded products, films, pipes, etc. It is widely used in various industrial and civil plastic products such as the automotive industry, household appliances, packaging industry, engineering plastics, and building materials.

[0003] The main polypropylene production processes are slurry process, bulk process, gas phase process and liquid phase bulk and gas combined process. The research and development of gas phase polypropylene process began in the early 1960s. Compared with slurry process and liquid phase bulk process, gas phase process has the advantages of being able to adjust product varieties in a wide range, easy to control the molecular weight and comonomer content of propylene products, suitable for the production of impact-resistant polypropylene resins, good device safety, and convenient start and stop. At present, newly built polypropylene devices basically adopt gas phase process and bulk process. With the continuous progress of high-activity and high-regularity polymerization catalysts, polypropylene process technology has been greatly developed, which not only simplifies the process flow, but also eliminates the process flow of removing catalyst residues and random polymers of by-products, improves product quality, and reduces the investment and production cost of production equipment.

[0004] The polypropylene processes at home and abroad are as follows:

[0005] 1) Gas phase polymerization process

[0006] ①Novolen process

[0007] The Novolen process was successfully developed by BASF. This gas phase process uses a vertical reactor with a double-screw stirring reactor for polymerization. This reactor can evenly distribute the PTK catalyst in the monomers of gas phase polymerization. The heat removal method of the polymerization reactor relies on the circulation of propylene gas. Liquid propylene is pumped into the reactor, and part of the polymerization heat is absorbed by the vaporization of propylene. The unreacted gaseous propylene is condensed with water to liquefy it and then pumped back to the reactor for use. The Novolen process can produce a wide range of various polypropylene products. The two reactors of the Novolen process can be designed as a "switchable" mode, that is, the two reactors can be connected in series to produce impact copolymers, or they can be operated in parallel to produce homopolymers and random products.

[0008] ②Unipol gas phase polypropylene process

[0009] Grace's Unipol gas phase process transplants the fluidized bed process used in polyethylene production equipment into the polypropylene process production, and has been successful. This process only needs one fluidized bed main reactor to produce homopolymer and random copolymer products, and the operating conditions can be adjusted within a large range to keep the product performance uniform. The Unipol process has the following advantages: ① Fully fluidized operation, simple reactor design; ② Can be used in conjunction with super-condensed state operation; ③ One fluidized bed main reactor can be used to produce homopolymers and random copolymers; ④ The operating conditions can be adjusted within a large operating range to keep the product performance uniform; ⑤ The process has low cost, short route, good performance, small footprint, great potential, no special requirements for materials, and is highly competitive.

[0010] ③Spherizone process

[0011] BaSell's Spherizone process is a gas phase, non-metallocene process developed on the basis of the Spheripol process. The main feature of this process is that it uses a single multi-zone circulating reactor (MZCR) instead of the loop reactor of the Spheripol process. The multi-zone circulating reactor is divided into two reaction zones, the ascending section and the descending section. The reaction temperature, hydrogen concentration, and monomer concentration can be controlled separately, and the gradually growing polymer particles are rapidly circulated multiple times in the two reaction zones. Homopolymer, binary and ternary random copolymer products can all be produced in the multi-zone circulating reactor, while impact copolymers require a gas phase fluidized bed reactor. Using the different operating modes of the multi-zone circulating reactor and the gas phase fluidized bed reactor, the Spherizone process can also produce some new types of products in addition to traditional homopolymer, random and impact products, such as twin random products, which can achieve a bimodal distribution of comonomer content. The Spherizone process greatly expands the performance range of polypropylene products. The Spherizone process can produce high-quality products, including all conventional polypropylene grades and some special product grades.

[0012] ④Innovene process

[0013] The Innovene gas phase polypropylene process was developed by Ineos. It can produce impact polypropylene from high flexural modulus to low temperature applications using two horizontal reactors in series, baffles and a special agitator system, and achieve a certain distribution of powder residence time in one reactor, achieving the effect of three full mixed flow reactors in series. The special agitator design makes it possible to quickly switch grades during the production process. The transition time for product switching is 2 / 3 less than that of a continuous stirring reactor, and it also reduces transitional products during production. The use of one catalyst to produce all ranges of polypropylene products including homopolymers, random copolymers and impact copolymers is a significant feature of this process. In addition, the Innovene process can quickly stop the addition of the main catalyst and quickly and smoothly stop the unit through the gas lock system, providing reliable protection for the safe operation of the device. However, two sets of complex gas lock systems are required for control between the two horizontal reactors for the production of impact copolymers.

[0014] 2) Process combining liquid phase bulk polymerization and gas phase polymerization

[0015] In view of the disadvantages of gas phase polymerization that it is easy to produce hot spots and plasticized blocks, the process of combining propylene liquid phase bulk polymerization and gas phase polymerization began to appear in the world in the mid-1980s. Among them, the most famous are two: Mitsui Petrochemical's "kettle + fluidized bed" (Hypol) process and Bassell's "loop + fluidized bed" (Spheripol) process, both of which can be summarized as the combined process of "propylene liquid phase bulk polymerization + fluidized bed gas phase polymerization". The bulk polymerization process is to disperse the catalyst directly into the liquid phase propylene, so that the liquid phase propylene undergoes polymerization reaction, and no solvent is added to the reaction system. The polymer is suspended in the liquid phase propylene in the form of fine particles, and the concentration of the polymer increases gradually with the reaction time. When the propylene conversion rate reaches a certain level, a granular polypropylene product can be obtained through a flash recovery system. Basell's Spheripol process consists of catalyst feeding, reaction, monomer flash, circulation, stripping, extrusion and mixing units. The main feature of the production is the use of serial loop reactors to produce homopolymers and random copolymers, and then the production of impact copolymers through serial gas phase reactors. This process can produce almost all products in a single loop reactor, but the device often uses two loop reactors in series to produce bimodal products to improve the mechanical properties of the product. If the impact copolymer is produced, another gas phase reactor needs to be connected in series. If block polypropylene is produced, the Spheripol process needs to be completed with a two-step composite process: the first step is to use a loop reactor for propylene liquid phase homopolymerization; the second step is to use a fluidized bed reactor for propylene homopolymer and ethylene monomer gas phase copolymerization, using the residual catalyst activity of the homopolymer from the loop reactor, adding ethylene and supplementary propylene and hydrogen to achieve the production of ethylene-propylene copolymer rubber, which greatly improves the impact resistance of the final product, especially the impact resistance at low temperatures. However, the steam and chilled water energy consumed by the medium-pressure flash tank and the deethylene tower are too large.

[0016] The SPG polypropylene continuous bulk polymerization process adopts a production method that combines propylene liquid phase bulk slurry polymerization with horizontal gas phase polymerization. It uses a high-efficiency carrier catalyst as the main catalyst, alkyl aluminum (triethyl aluminum) as the co-catalyst, silane as the electron donor, hydrogen as the molecular weight regulator, and propylene as the polymerization monomer. Polypropylene powder is obtained through propylene slurry polymerization and gas phase polymerization. The device consists of a propylene refining and feeding system, a catalyst feeding system, a polymerization reaction system, a polypropylene drying and transportation system, a propylene recovery system, a hydrogen circulation system, and a utility system. This process is suitable for the continuous transformation of many intermittent polypropylene units and for the construction of large-scale polypropylene units. The localization rate of the industrialized equipment of this process is 100%. Under the condition of using the same catalyst, the product quality has been tested and compared by the National Polyolefin Research Center: important physical properties such as tensile strength and flexural modulus are significantly higher than those of imported equipment. The advancement of the process and the economic efficiency of the device operation have also been verified and recognized. However, the polypropylene product grades are not complete, and high-quality impact-resistant polypropylene products cannot be produced.

[0017] In addition, the existing gas phase polypropylene process is usually used to produce impact copolymers with two reactors in series. Only propylene and hydrogen are added to the first reactor (i.e., the first reactor) to produce homopolymers; ethylene, propylene, and hydrogen are added to the second reactor (i.e., the second reactor) to produce impact copolymers. The polymerization monomers of the two reactors are propylene and ethylene; the main function of hydrogen is to terminate the growth of the polymerization chain segment and produce polymers with the required melt flow rate (MFR). In order to control the rigidity and toughness balance of the impact copolymer products, the amount of propylene and hydrogen added to the first reactor is much greater than that of the second reactor. In order to avoid the amount of hydrogen and propylene entrained by the first reactor product (homopolymer) exceeding the demand of the second reactor, and the ethylene backflow from the second reactor system to the first reactor, two sets of parallel gas lock systems are usually set between the first reactor and the second reactor (including receiving tanks, gas locks, propylene gasifiers, degassing compressors, programmable valves, etc., which control the injection, low-pressure gas lift & degassing, powder filling and pressure delivery, degassing compression recovery). The air lock system introduced in this process increases the equipment investment and also improves the operating requirements, and it is also impossible to produce full-grade polypropylene powder. Summary of the invention

[0018] The purpose of the present invention is to provide a production device and a production process of impact-resistant polypropylene based on a dehydrogenation bin-depropylene tower, so as to realize the production of high-quality full-grade polypropylene products.

[0019] The purpose of the present invention can be achieved by the following technical solutions:

[0020] One of the technical solutions of the present invention provides a production device of impact-resistant polypropylene based on a dehydrogenation bin-depropylene tower, comprising a first reactor and a second reactor arranged in sequence along the flow direction of the main material, a dehydrogenation bin is also provided between the first reactor and the second reactor, a depropylene tower is also provided next to the second reactor for receiving condensate formed by condensation of the gas phase at the top thereof, the top outlet of the depropylene tower is also returned to connect to the second reactor, and the bottom outlet of the tower is also returned to connect to the dehydrogenation bin.

[0021] Furthermore, the first reactor, the dehydrogenation chamber and the second reactor are gradually lowered in horizontal height, and the operating pressures in the first reactor, the dehydrogenation chamber and the second reactor are also successively lowered.

[0022] Furthermore, the top gas phase outlet of the first reactor is also provided with a first condensation loop with a first condenser, and the top of the dehydrogenation chamber is also returned and connected to the first condenser.

[0023] Furthermore, a pressure difference control valve is provided between the first reactor and the first condenser, so that the pressures in the first reactor, the dehydrogenation chamber and the first condenser are reduced in sequence.

[0024] Furthermore, the top gas phase outlet of the second reactor is also provided with a second condensation circuit with a second condenser and a condensate pump, and the condensate pump outlet is also connected to the depropylene tower through a pipeline.

[0025] Furthermore, a propylene gasifier is provided between the propylene removal tower and the dehydrogenation chamber.

[0026] Furthermore, a prepolymerization reactor is provided before the first reactor.

[0027] Furthermore, the outlet of the second reactor is also connected to a filter.

[0028] The second technical solution of the present invention provides a gas phase polypropylene production process without an air lock, which is implemented using the production device as described above, and includes the following steps:

[0029] (1) Propylene, ethylene and hydrogen are introduced into a first reactor for gas phase polymerization to obtain a homopolymer as a first reaction product;

[0030] (2) The first reaction product is subjected to the action of stripping propylene in the dehydrogenation chamber to remove part of the hydrogen and propylene carried by the homopolymer, and then enters the second reactor, while the degassing discharged from the top of the dehydrogenation chamber is returned to the first condenser at the first reactor for condensation and reuse;

[0031] (3) continuing to introduce ethylene and supplemental hydrogen into the second reactor to carry out a gas phase impact polymerization reaction to obtain an impact copolymer;

[0032] (4) After the gas phase at the top of the second reactor is condensed, part of the condensate obtained is returned to the second reactor for reuse, and part is sent to the depropylene tower. Propylene is obtained at the bottom of the depropylene tower and is gasified and sent to the dehydrogenation warehouse as gas stripping propylene.

[0033] Furthermore, when a prepolymerization reactor is provided before the first reactor, the prepolymerization product obtained by the slurry polymerization reaction of propylene, ethylene and hydrogen in the prepolymerization reactor is also sent to the first reactor for further reaction.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] (1) A dehydrogenation chamber is arranged between the first reactor and the second reactor. The heights of the first reactor (i.e., the first reactor), the dehydrogenation chamber and the second reactor (i.e., the second reactor) are gradually lowered, and a micro-pressure reduction operation is performed in sequence. The product of the first reactor (homopolymer) continuously enters the dehydrogenation chamber from the top, and gasified propylene is introduced into the bottom of the dehydrogenation chamber. After most of the entrained hydrogen is removed, the propylene-rich powder flows from the bottom of the dehydrogenation chamber into the second reactor by gravity.

[0036] (2) A pressure differential control valve is installed between the first reactor and the first condenser to maintain the pressure balance of the first reactor, dehydrogenation chamber and condenser (step by step), so that the degassing self-pressure returns to the first condenser. Then, the degassing and first reactor circulating gas are condensed and cooled together in the first condenser, and the condensate and gas obtained in the corresponding condensate tank are returned to the first reactor through the circulating gas compressor and condensate pump respectively.

[0037] (2) By setting up a propylene removal tower, the propylene condensate formed by the gas phase circulation at the top of the second reactor can be received, and ethylene rich in propylene is obtained at the top of the tower to circulate in the second reactor; the propylene obtained at the bottom of the tower is returned to the dehydrogenation chamber as a gas stripping medium, and is returned to the first reactor together with the entrained propylene rich in hydrogen through a compressor. In this way, while removing hydrogen, the problem of excess propylene entering the third reactor system is solved.

[0038] (3) The impact copolymerization of the entire device adopts a combined process of a dehydrogenation chamber and a depropylene tower to replace the traditional gas lock system. It does not require the introduction of technology, has low investment, low energy consumption, convenient operation, and is safe and reliable. At the same time, in terms of technical effects, it effectively solves the problem of excess hydrogen and propylene. Not only is the operation process simple (continuous operation, no gas lock system required), but it also reduces the energy consumption of the device. It can be used for the production of high-quality, full-grade (including homopolymers, random copolymers, impact copolymers, terpolymers) polypropylene powders and pellets. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the present invention;

[0040] Figure 2 It is a structural schematic diagram of another form of the present invention;

[0041] Description of the markings in the figure:

[0042] 1-prepolymerization reactor;

[0043] 2-first reactor, 21-first cyclone separator, 22-first condenser, 23-first gas-liquid separation tank, 24-first circulation compressor;

[0044] 3-second reactor, 31-second cyclone separator, 32-second condenser, 33-second gas-liquid separation tank, 34-second compressor;

[0045] 4-dehydrogenation chamber;

[0046] 5-propylene removal tower;

[0047] 6- Filter;

[0048] 7-Propylene gasifier. DETAILED DESCRIPTION

[0049] 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.

[0050] In the following implementation manners or examples, unless otherwise specified, functional components or structures are conventional components or conventional structures used in the art to achieve corresponding functions.

[0051] In order to realize the production of high-quality full-grade polypropylene products, the present invention provides a production device of impact-resistant polypropylene based on a dehydrogenation bin-depropylene tower, and its structure is shown in Figure 1 As shown, it includes a first reactor and a second reactor arranged in sequence along the flow direction of the main material, a dehydrogenation chamber is also arranged between the first reactor and the second reactor, and a depropylene tower is also arranged next to the second reactor to receive the condensate formed by the condensation of the gas phase at the top thereof, and the top outlet of the depropylene tower is also returned to connect to the second reactor, and the bottom outlet of the tower is also returned to connect to the dehydrogenation chamber. In the present invention, both the first reactor and the second reactor can be horizontal reactors.

[0052] In some specific embodiments, the first reactor, the dehydrogenation chamber and the second reactor are gradually lowered in horizontal height, and the operating pressures in the first reactor, the dehydrogenation chamber and the second reactor are also successively lowered to ensure smooth flow of powder.

[0053] In some specific embodiments, the top gas phase outlet of the first reactor is also provided with a first condensation circuit with a first condenser, and the top of the dehydrogenation chamber is also connected back to the first condenser. Here, a first cyclone separator is generally provided in front of the first condenser, and the outlet of the first condenser is also connected in sequence to a first condensate tank and a first condensate pump, so that the condensate obtained by condensation and separation at the first condenser can be returned to the first reactor for reuse through the first condensate pump, and at the same time, the gas phase separated at the first condensate tank can be pressed into the top of the first reactor together with ethylene and hydrogen materials through the first circulation compressor. At the same time, the propylene material can be sent to the first condensate tank and then enter the reaction system of the first reactor.

[0054] Furthermore, a pressure difference control valve is provided between the first reactor and the first condenser, so that the pressure in the first reactor, the dehydrogenation chamber and the first condenser is reduced in sequence, so that the degassing obtained at the top of the dehydrogenation chamber can return to the first condenser by self-pressure.

[0055] In some specific embodiments, the top gas phase outlet of the second reactor is also provided with a second condensation circuit with a second condenser and a condensate pump (i.e., a second condensate pump), and the condensate pump outlet is also connected to the propylene removal tower through a pipeline. More specifically, a second cyclone separator is also provided in front of the second condenser, and a second condensate tank is provided between the first condenser and the second condensate pump. The condensate discharged by the second condensate pump is partially sent to the propylene removal tower, and the rest is returned to the second reactor for reuse.

[0056] In some specific embodiments, a propylene vaporizer is further provided between the propylene removal tower and the dehydrogenation chamber. In the propylene removal tower, the ethylene-rich non-condensable gas at the top of the tower is self-pressurized to return to the second reactor through the manifold at the outlet of the second circulation compressor (together with the additional hydrogen, ethylene, and the non-condensable gas at the top of the second condensate tank), and the propylene (excluding ethylene) at the bottom of the tower is pumped into the propylene vaporizer and returned to the first reactor as vaporized propylene through the top of the dehydrogenation chamber. The propylene removal tower only controls the ethylene content in the propylene at the bottom of the tower, and its recovery rate requirement is not high. The non-condensable gas at the top of the tower can be rich in propylene, so the reflux ratio of the tower is very small, the energy consumption is very low, and the condensation temperature of the top gas is relatively high (>40°C), and circulating water can be used as a cooling medium.

[0057] In some specific implementations, please refer to Figure 2 As shown, a prepolymerization reactor is also provided before the first reactor.

[0058] In some specific embodiments, the outlet of the second reactor is also connected to a filter.

[0059] In addition, the present invention also provides a gas phase polypropylene production process without an air lock, which is implemented using the production device as described above, and includes the following steps:

[0060] (1) Propylene, ethylene and hydrogen are introduced into a first reactor for gas phase polymerization to obtain a homopolymer as a first reaction product;

[0061] (2) The first reaction product is subjected to the action of stripping propylene in the dehydrogenation chamber to remove part of the hydrogen and propylene carried by the homopolymer, and then enters the second reactor, while the degassing discharged from the top of the dehydrogenation chamber is returned to the first condenser at the first reactor for condensation and reuse;

[0062] (3) continuing to introduce ethylene and supplemental hydrogen into the second reactor to carry out a gas phase impact polymerization reaction to obtain an impact copolymer;

[0063] (4) After the gas phase at the top of the second reactor is condensed, part of the condensate obtained is returned to the second reactor for reuse, and part is sent to the depropylene tower. Propylene is obtained at the bottom of the depropylene tower and is gasified and sent to the dehydrogenation warehouse as gas stripping propylene.

[0064] In some specific embodiments, when a prepolymerization reactor is provided before the first reactor, the prepolymerization product obtained by the slurry polymerization reaction of propylene, ethylene and hydrogen in the prepolymerization reactor is also sent to the first reactor for further reaction.

[0065] The above embodiments may be implemented individually or in any combination of two or more.

[0066] The above implementation is described in more detail below in conjunction with specific examples.

[0067] Embodiment 1:

[0068] In combination with the above implementation modes, and with reference to Figure 1 Taking a 300,000 t / a gas phase polypropylene unit as an example, the powder production capacities of homopolymerization, random copolymerization and impact copolymerization are 40 t / h, 37.5 t / h and 34.8 t / h respectively. Among them, in order to control the rubber content and ethylene content of the impact copolymer, the production capacity of the first reactor (i.e. the first reactor) under low ethylene impact copolymerization conditions is 30,455 kg / h, and the production capacity of the second reactor (i.e. the second reactor) is 4,345 kg / h; the production capacity of the first reactor under high ethylene impact copolymerization conditions is 26,452 kg / h, and the production capacity of the second reactor is 8,352 kg / h.

[0069] The first reactor and the second reactor are both stirred bed gas phase reactors, which adopt pulse discharging. The unreacted hydrogen-rich propylene gas entrained in the first reaction product usually accounts for about 10% of the powder, wherein: under low ethylene impact copolymerization conditions, the first reaction product entrains 2618kg / h of propylene, which is 1908kg / h more than the propylene demand of the second reaction, and at least 710kg / h of propylene needs to be removed from the second reaction system through the propylene removal tower; under high ethylene impact copolymerization conditions, the first reaction entrains 0.25kg / h of hydrogen, which is 0.14kg / h more than the hydrogen demand of the second reaction, and at least 0.11kg / h of hydrogen needs to be removed through the dehydrogenation warehouse system.

[0070] 1) Low ethylene copolymerization conditions:

[0071] 3000kg / h of propylene condensate (ethylene 10.8%, propylene 82.0%) is introduced from the outlet of the second condensate pump to the depropylene tower. When the propylene recovery rate at the bottom of the tower is controlled to be 50% and the ethylene content is ≯10wppm, the condensation temperature at the top of the tower is 42°C, the reflux ratio is 0.80, and the calculated tower diameter is 911mm. The non-condensable gas at the top of the tower (ethylene 21.5%, propylene 72.7%) is returned to the second reactor by self-pressure through the manifold at the outlet of the second circulation compressor; the propylene at the bottom of the tower (propylene 10wppm) is 1499kg / h, and it is returned to the first reactor by pump pressure through the propylene gasifier and dehydrogenation chamber. The insufficient part of the two-trans propylene (1499-710=789kg / h) is supplemented by the propylene feeding system.

[0072] 2) High ethylene copolymerization conditions:

[0073] About 3000 kg / h of gasified propylene is introduced into the lower part of the dehydrogenation chamber to dilute the hydrogen entrained with propylene gas (2572 kg / h, including 0.25 kg / h of hydrogen) in the first reaction product, ensuring that the amount of hydrogen entering the second reaction from the bottom of the dehydrogenation chamber is less than the demand of the second reaction (0.14 kg / h). The insufficient hydrogen in the second reaction is supplemented by the hydrogen supply system.

[0074] The material process conditions of this embodiment are as follows:

[0075]

[0076] In general, the process flow of this embodiment is suitable for the production of propylene homopolymerization, random copolymerization and impact copolymerization, and can achieve long-term operation to produce polypropylene products.

[0077] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in 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 present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A production device for impact-resistant polypropylene based on a dehydrogenation chamber-depropylene tower, characterized in that: It comprises a first reactor and a second reactor which are sequentially arranged along the flow direction of the main material, a dehydrogenation chamber is arranged between the first reactor and the second reactor, a depropylene tower is arranged beside the second reactor to receive the condensate formed by the condensation of the gas phase at the top thereof, the top outlet of the depropylene tower is also returned to connect to the second reactor, and the bottom outlet of the tower is also returned to connect to the dehydrogenation chamber; The first reactor, the dehydrogenation chamber and the second reactor are gradually lowered in level, and the operating pressures in the first reactor, the dehydrogenation chamber and the second reactor are also lowered in sequence; The top gas phase outlet of the first reactor is also provided with a first condensation loop with a first condenser, and the top of the dehydrogenation tank is also returned and connected to the first condenser; A pressure difference control valve is also provided between the first reactor and the first condenser, so that the pressures in the first reactor, the dehydrogenation chamber and the first condenser are reduced in sequence.

2. The production device of impact-resistant polypropylene based on dehydrogenation warehouse-depropylene tower according to claim 1, characterized in that: The top gas phase outlet of the second reactor is also provided with a second condensation circuit with a second condenser and a condensate pump, and the condensate pump outlet is also connected to the depropylene tower through a pipeline.

3. The production device of impact-resistant polypropylene based on dehydrogenation warehouse-depropylene tower according to claim 1, characterized in that: A propylene gasifier is also provided between the propylene removal tower and the dehydrogenation chamber.

4. The production device of impact-resistant polypropylene based on dehydrogenation warehouse-depropylene tower according to claim 1, characterized in that: A prepolymerization reactor is also arranged before the first reactor.

5. The production device of impact-resistant polypropylene based on dehydrogenation warehouse-depropylene tower according to claim 1, characterized in that: The outlet of the second reactor is also connected to a filter.

6. A production process of impact-resistant polypropylene based on a dehydrogenation chamber-depropylene tower, which is implemented by using the production device according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Propylene and hydrogen are introduced into a first reactor for gas phase polymerization to obtain a homopolymer as a first reaction product; (2) The first reaction product is subjected to the action of stripping propylene in the dehydrogenation chamber to remove part of the hydrogen and propylene carried by the homopolymer, and then enters the second reactor, while the degassing discharged from the top of the dehydrogenation chamber is returned to the first condenser at the first reactor for condensation and reuse; (3) continuing to introduce ethylene and supplemental hydrogen into the second reactor to carry out a gas phase impact polymerization reaction to obtain an impact copolymer; (4) After the gas phase at the top of the second reactor is condensed, part of the condensate obtained is returned to the second reactor for reuse, and part is sent to the depropylene tower. Propylene is obtained at the bottom of the depropylene tower and is gasified and sent to the dehydrogenation warehouse as gas stripping propylene.

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