CN116515028A

CN116515028A - Production device and process of impact-resistant polypropylene based on dehydrogenation bin-de-acrylic tower

Info

Publication number: CN116515028A
Application number: CN202210080872.8A
Authority: CN
Inventors: 武长江; 李彦磊; 张韩
Original assignee: SHANGHAI HOTO ENGINEERING Inc
Current assignee: SHANGHAI HOTO ENGINEERING Inc
Priority date: 2022-01-24
Filing date: 2022-01-24
Publication date: 2023-08-01

Abstract

The invention relates to a production device and a process of impact polypropylene based on a dehydrogenation bin-a deallylation tower, wherein the device comprises a first reactor and a second reactor which are sequentially arranged along the flowing direction of main materials, a dehydrogenation bin is further arranged between the first reactor and the second reactor, a deallylation tower for receiving condensate formed by condensing gas phase at the top of the second reactor is further arranged beside the second reactor, the top outlet of the deallylation tower is further connected with the second reactor in a return way, and the bottom outlet of the deallylation tower is further connected with the dehydrogenation bin in a return way. The invention adopts the combined process of the dehydrogenation bin and the de-propenoic tower, effectively solves the problem of surplus hydrogen and propylene, has simple operation process (continuous operation, no need of an airlock system), reduces the energy consumption of the device, and can be used for producing high-quality and full-grade (including homopolymer, random copolymer, impact copolymer and terpolymer) polypropylene powder and granules.

Description

Production device and process of impact-resistant polypropylene based on dehydrogenation bin-de-acrylic tower

Technical Field

The invention belongs to the technical field of polypropylene production, and relates to a production device and a production process of impact-resistant polypropylene based on a dehydrogenation bin-a deallylation tower.

Background

Polypropylene is a thermoplastic synthetic resin with excellent performance, which is produced by polymerization reaction of propylene monomers under the action of a catalyst. The polypropylene has the advantages of no toxicity, chemical resistance, low relative density, heat resistance, easy processing and forming, and the like, can be processed into woven products, injection molded products, films, pipes, and the like, and has wide application in the fields of various industrial and civil plastic products such as automobile industry, household appliances, packaging industry, engineering plastics, building materials, and the like.

The polypropylene production process mainly comprises a slurry process, a bulk process, a gas phase process and a process combining a liquid phase bulk process and gas. The study and development of the gas phase polypropylene process began in the early 60 s of the 20 th century. Compared with slurry method and liquid phase bulk method, the gas phase method has the advantages of wide range of product variety adjustment, easy control of propylene product molecular weight and comonomer content, suitability for producing anti-impact polypropylene resin, good safety of device and convenient start and stop. The currently newly built polypropylene devices basically use gas phase processes and bulk processes. Along with the continuous progress of high activity and high isotacticity polymerization catalyst, the polypropylene process technology is greatly developed, so that the process flow is simplified, the process flow of removing catalyst residues, random polymers of byproducts and the like is omitted, the quality of products is improved, and the investment and production cost of production devices are reduced.

The technology of polypropylene at home and abroad is as follows:

1) Gas phase polymerization process

(1) Novolen process

The Novolen process was successfully developed by BASF and the gas phase process was carried out using a stirred vertical reactor with double helical bands which allowed the PTK catalyst to be distributed uniformly in the monomers being gas phase polymerized. The heat removal mode of the polymerization reactor is based on the circulation of propylene gas. Pumping liquid propylene into a reactor, absorbing a part of polymerization heat through vaporization of propylene, condensing unreacted gaseous propylene with water to liquefy the unreacted gaseous propylene, and pumping the liquefied propylene back into the reactor for use. The Novolen process can produce a wide variety of polypropylene products. The apparatus of the two reactors of the Novolen process can be designed in a "switchable" mode, i.e.the two reactors can be operated in series to produce impact copolymers, or in parallel to produce homopolymers and random products.

(2) Unipol gas phase polypropylene process

The Unipol gas phase process of Grace company was a fluidized bed process applied in a polyethylene production plant, transplanted into polypropylene process production, and was successful. The process can produce homopolymer and random copolymer with only one main fluidized bed reactor, and has homogeneous product performance. The Unipol process has the following advantages: (1) the full fluidization operation is carried out, and the reactor is simple in design; (2) can be operated in a super-condensation state; (3) the production of homopolymers and random copolymers can be carried out using a main fluidized-bed reactor; (4) the operating conditions can be adjusted within a larger operating range so as to keep the product performance uniform; (5) the process has the advantages of low cost, short route, good performance, small occupied area, large potential, no special requirement on materials and stronger competitiveness.

(3) Spherizone process

The Spherizone process of the ball company is a gas phase, non-metallocene process and was developed on the basis of the Spheripol process. The main feature of the process is the loop reactor by using a single multizone circulating reactor (MZCR) instead of the Spheripol process. The multi-zone circulating reactor is divided into 2 reaction zones of an ascending zone and a descending zone, the reaction temperature, the hydrogen concentration and the monomer concentration can be respectively controlled, and the gradually-growing polymer particles rapidly circulate for many times in the two reaction zones. The homo-, binary-and ternary random copolymer products can be produced in a multi-zone circulating reactor, and the impact copolymer needs to be provided with a gas-phase fluidized bed reactor. By utilizing different modes of operation of the multizone circulating reactor and the gas phase fluidized bed reactor, the spheronizone process can also produce some new types of products, such as a binary random product, in addition to conventional homo-, random-and impact-resistant products, which can achieve a bimodal distribution of comonomer content. The Spherizone process greatly expands the performance range of polypropylene products. The spheronizone process can be used for producing high-quality products, including all polypropylene regular marks and part of special product marks.

(4) Innovene process

The Innovene gas-phase polypropylene process is developed by Ineos corporation, and can utilize 2 horizontal reactors, baffle plates and special stirrer systems which are connected in series to produce impact polypropylene with high flexural modulus and low-temperature application, so that a certain powder residence time distribution is formed in 1 reactor, the effect of connecting 3 fully mixed flow reactors in series is achieved, the special stirrer design enables quick grade switching in the production process to be possible, the transition time of product switching is 2/3 less than that of a continuous stirring reactor, and meanwhile, the transition products in production are reduced. The ability to produce polypropylene products in all ranges of homo-, random-and impact-copolymerization using one catalyst is a significant feature of the process. And the Innovene process can rapidly stop the addition of the main catalyst through the air lock system to rapidly and stably stop the operation, thereby providing reliable guarantee for the safe operation of the device. But 2 sets of complex airlock systems are needed to control between two horizontal reactors for producing the impact copolymerization.

2) Process for combining liquid phase bulk polymerization with gas phase polymerization

Aiming at the defects that hot spots and plasticizing blocks are easy to generate in gas-phase polymerization, a process combining propylene liquid-phase bulk polymerization and gas-phase polymerization begins to appear in the middle world of the last 80 th century. Among the most notable are 2: the three-well petrochemical "kettle+fluidized bed" (Hypol) process and the Bassell corporation "loop+fluidized bed" (Spheresol) process, both of which can be generalized to this combined process of "propylene liquid phase bulk polymerization+fluidized bed gas phase polymerization". The bulk polymerization process is to disperse the catalyst directly into liquid propylene to make the liquid propylene to polymerize and to avoid adding solvent into the reaction system. The polymer is suspended in liquid propylene in fine particle form, and the concentration of the polymer is increased gradually with the lapse of reaction time, and the granular polypropylene product is obtained through a flash evaporation recovery system after the propylene conversion rate reaches a certain degree. The Spheripol process of Basell consists of catalyst feeding, reaction, monomer flashing, circulation, stripping, extrusion and mixing units, and the main characteristic of the production is that a series loop reactor is used to produce homopolymer and random copolymer, and then a series gas phase reactor is used to produce impact copolymer. The process can produce products in almost all ranges by using single loop reactors, but the device usually uses 2 loop reactors in series to produce bimodal products to improve the mechanical properties of the products, and if impact copolymers are produced, 1 gas phase reactor is needed in series. If a block polypropylene is produced, the spheropol process requires a two-step compounding process to complete the production: the first step adopts a loop reactor to carry out propylene liquid phase homopolymerization reaction; and in the second step, a fluidized bed reactor is adopted to carry out gas-phase copolymerization reaction of propylene homopolymer and ethylene monomer, and ethylene and supplemental propylene and hydrogen are added by utilizing the residual catalyst activity of the homopolymer from the loop reactor to realize the production of ethylene-propylene copolymer rubber, so that the impact resistance of the final product, especially at low temperature, is greatly improved. But the energy consumption of the steam and chilled water consumed by the medium pressure flash tank and the deethylenizer is excessive.

The SPG polypropylene continuous process adopts a production method combining propylene liquid phase bulk slurry polymerization and horizontal gas phase polymerization, takes a high-efficiency carrier catalyst as a main catalyst, takes aluminum alkyl (triethylaluminum) as a cocatalyst, takes silane as an electron donor, takes hydrogen as a molecular weight regulator, takes propylene as a polymerization monomer, and obtains polypropylene powder through propylene slurry polymerization and gas phase polymerization successively. The device consists of a propylene refining and feeding system, a catalyst feeding system, a polymerization reaction system, a polypropylene drying and conveying system, a propylene recovery system, a hydrogen circulation system and a public engineering system. The process is suitable for continuous transformation of a plurality of intermittent polypropylene devices and is also suitable for construction of large-scale polypropylene devices. The localization rate of equipment of the industrial device of the process reaches 100 percent, and under the condition of using the same catalyst, the quality of the product is tested and compared by the national polyolefin research center: important physical indexes such as tensile strength, flexural modulus and the like obviously exceed those of the product of the introduction device. The advancement of the process and the economical efficiency of the device operation are also verified and approved. However, the polypropylene product is not fully branded and cannot be produced into high-quality impact-resistant polypropylene products.

In addition, when the existing gas phase polypropylene process is used for producing the impact copolymer, two reactors connected in series are usually arranged, and propylene and hydrogen are only added into one reactor (namely the first reactor) to produce the homopolymer; ethylene, propylene, and hydrogen are added in a two-reactor (i.e., second reactor) to produce an impact copolymer. The polymerized monomers of the two reactors are propylene and ethylene; the primary function of hydrogen is to terminate the growth of the polymeric segment, producing a polymer of the desired Melt Flow Rate (MFR). In order to control the rigidity and toughness balance of the impact copolymer product, the addition amount of the first anti-propylene and the hydrogen is far greater than that of the second anti-propylene, and in order to avoid that the hydrogen and the propylene carried by the first anti-product (homopolymer) are greater than that of the second anti-demand and the ethylene of the second anti-system is reversely changed into one anti-reaction, 2 sets of air lock systems (comprising a material receiving tank, an air lock device, a propylene gasifier, a degassing compressor, a program control valve and the like) are arranged between the first anti-reaction and the second anti-reaction, and the injection, the low-pressure gas stripping and the degassing are controlled in sequence, and the powder is pressurized, sent, degassed, compressed and recycled. The airlock system introduced in the process increases equipment investment, simultaneously increases operation requirements, and also cannot produce full-grade polypropylene powder.

Disclosure of Invention

The invention aims to provide a production device and a production process of impact-resistant polypropylene based on a dehydrogenation bin-deallylation tower, so as to realize the production of high-quality full-brand polypropylene products and the like.

The aim of the invention can be achieved by the following technical scheme:

the invention provides a production device of impact polypropylene based on a dehydrogenation bin-a dealumination tower, which comprises a first reactor and a second reactor which are sequentially arranged along the flowing direction of main materials, wherein a dehydrogenation bin is further arranged between the first reactor and the second reactor, the dealumination tower which is used for receiving condensate formed by condensing gas phase at the top of the second reactor is further arranged beside the second reactor, the top outlet of the dealumination tower is further connected with the second reactor in a return way, and the bottom outlet of the dealumination tower is further connected with the dehydrogenation bin in a return way.

Further, the first reactor, the dehydrogenation bin and the second reactor are gradually reduced in horizontal height, and the operating pressures in the first reactor, the dehydrogenation bin and the second reactor are also sequentially reduced.

Further, the top gas phase outlet of the first reactor is also provided with a first condensing loop with a first condenser, and the top of the dehydrogenation bin is also connected with the first condenser in a return way.

Furthermore, a differential pressure control valve is further arranged between the first reactor and the first condenser, so that the pressures in the first reactor, the dehydrogenation bin and the first condenser are sequentially reduced.

Further, a second condensing loop with a second condenser and a condensate pump is further arranged at the top gas phase outlet of the second reactor, and the condensate pump is further connected with the de-acrylic tower through a pipeline.

Further, a propylene gasifier is arranged between the de-acrylic tower and the dehydrogenation bin.

Furthermore, a prepolymerization reactor is arranged in front of the first reactor.

Further, the outlet of the second reactor is also connected with a filter.

The second technical scheme of the invention provides a gas-phase polypropylene production process based on no airlock device, which is implemented by adopting the production device, and comprises the following steps:

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

(2) The reaction product is subjected to gas stripping propylene in a dehydrogenation bin, part of hydrogen and propylene carried by homopolymer are removed, and then the reaction product enters a second reactor, and degassing discharged from the top of the dehydrogenation bin is returned to a first condenser at the first reactor for condensation recycling;

(3) Continuously introducing ethylene and supplementary hydrogen into the second reactor to carry out gas-phase impact polymerization reaction to obtain an impact copolymer;

(4) And (3) condensing the gas phase at the top of the second reactor, returning part of the condensate obtained after condensing to the second reactor for recycling, and sending part of the condensate into a dealumination tower, obtaining propylene at the bottom of the dealumination tower, gasifying the propylene, and sending the propylene into a dehydrogenation bin to be used as gas stripping propylene.

Further, when a prepolymerization reactor is further arranged in front of the first reactor, a prepolymerization product obtained by slurry polymerization of propylene, ethylene and hydrogen in the prepolymerization reactor is also fed into the first reactor for continuous reaction.

Compared with the prior art, the invention has the following advantages:

(1) The dehydrogenation bin is arranged between the first reactor and the second reactor, the heights of the first reactor (namely, one reaction), the dehydrogenation bin and the second reactor (namely, two reactions) are gradually reduced, sequential micro-depressurization operation is adopted, one reaction product (homopolymer) continuously enters the dehydrogenation bin from the upper part, gasified propylene is introduced into the lower part of the dehydrogenation bin, and after most of entrained hydrogen is removed, propylene-rich powder enters the second reactor from the gravity flow at the bottom of the degassing bin.

(2) A differential pressure control valve is arranged between the first reactor and the first condenser: the pressure (step-by-step) balance of the counter, dehydrogenation bin and condenser is maintained, and the degassing self-pressure is returned to the first condenser. Then, the deaerated and the reverse circulation gas are condensed and cooled together in the first condenser, and the condensate and the gas obtained in the corresponding condensate tank are returned to the first reactor through the circulation gas compressor and the condensate pump respectively.

(2) By arranging the deallyzing tower, the propylene condensate formed by gas phase circulation at the top of the second reactor can be received, and the ethylene rich in propylene is obtained at the top of the tower and circulated in the second reactor; and (3) obtaining propylene from the bottom of the tower and returning the propylene to the dehydrogenation bin as a gas stripping working medium, and returning the propylene and the entrained propylene rich in hydrogen to the first reactor through a compressor. Thus, the problem of propylene surplus entering the third reactor system is solved while hydrogen is stripped off.

(3) The whole device adopts the combined process of the dehydrogenation bin and the dealacrylic tower to replace the traditional airlock system, does not need the introduction technology, has the advantages of investment saving, low energy consumption, convenient operation, safety and reliability. Meanwhile, in the technical effect, the problem of surplus hydrogen and propylene is effectively solved, the operation process is simple (continuous operation is not needed, an airlock system is not needed), the energy consumption of the device is reduced, and the method can be used for producing high-quality and full-grade (including homopolymers, random copolymers, impact copolymers and terpolymers) polypropylene powder and granules.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic view of another form of construction of the present invention;

the figure indicates:

1-a prepolymerization reactor;

2-a first reactor, 21-a first cyclone, 22-a first condenser, 23-a first gas-liquid separation tank, 24-a first recycle compressor;

3-a second reactor, 31-a second cyclone, 32-a second condenser, 33-a second gas-liquid separation tank, 34-a second compressor;

4-a dehydrogenation bin;

a 5-deallylation column;

6-a filter;

7-propylene gasifier.

Detailed Description

The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following examples.

In the following embodiments or examples, unless otherwise specified, functional components or structures are indicated as conventional components or structures employed in the art to achieve the corresponding functions.

The invention provides a production device of impact polypropylene based on a dehydrogenation bin-a dealkylation tower, which is shown in the structure shown in figure 1, and comprises a first reactor and a second reactor which are sequentially arranged along the flowing direction of main materials, wherein a dehydrogenation bin is further arranged between the first reactor and the second reactor, a dealkylation tower for receiving condensate formed by condensing the top gas phase of the dealkylation tower is further arranged beside the second reactor, the top outlet of the dealkylation tower is further connected with the second reactor, and the bottom outlet of the dealkylation tower is further connected with the dehydrogenation bin. In the present invention, both the first reactor and the second reactor may be horizontal reactors.

In some specific embodiments, the first reactor, the dehydrogenation bin and the second reactor are gradually reduced in level, and the operating pressures in the first reactor, the dehydrogenation bin and the second reactor are also sequentially reduced, so that smooth powder circulation is ensured.

In some embodiments, the top gas phase outlet of the first reactor is further provided with a first condensing loop with a first condenser, and the top of the dehydrogenation bin is further connected back to the first condenser. Here, a first cyclone separator is generally further arranged in front of the first condenser, and the outlet of the first condenser is further sequentially connected with a first condensate tank and a first condensate pump, so that condensate obtained by condensation and separation at the first condenser can be returned to the first reactor for recycling through the first condensate pump, and meanwhile, gas phase obtained by separation at the first condensate tank can be pressed into the top of the first reactor together with ethylene and hydrogen materials through the first circulating compressor. Meanwhile, propylene materials can be sent into the first condensate tank and then enter the reaction system of the first reactor.

Still further, still be equipped with pressure differential control valve between first reactor and the first condenser for the pressure in first reactor, dehydrogenation storehouse and the first condenser reduces in proper order, makes the degasification that dehydrogenation storehouse top obtained can return first condenser from the pressure.

In some specific embodiments, the top gas phase outlet of the second reactor is further provided with a second condensation loop with a second condenser and a condensate pump (i.e., a second condensate pump), and the condensate pump is further connected to the deallyzing tower through a pipeline. More specifically, a second cyclone separator is also arranged in front of the second condenser, and a second condensate tank is also arranged between the first condenser and the second condensate pump. And sending part of the condensate discharged by the second condensate pump into the dealkage tower, and returning the rest part of the condensate into the second reactor for recycling.

In some specific embodiments, a propylene gasifier is further disposed between the de-allyl column and the dehydrogenation bin. In the dealumination tower, the non-condensable gas at the top of the tower, which is rich in ethylene, is automatically pressed to return to the second reactor through a collecting pipe at the outlet of the second circulating compressor (together with the hydrogen, the ethylene and the non-condensable gas at the top of the second condensate tank which are added in a supplementing way), and propylene (without ethylene) at the bottom of the tower is pumped into a propylene gasifier to be used as gasified propylene to return to the first reactor through the top of the dehydrogenation bin. The deallylation tower only controls the ethylene content in propylene at the bottom of the tower, the recovery rate is low, the non-condensable gas at the top of the tower can be rich in propylene, so that the reflux ratio of the tower is small, the energy consumption is low, the condensing temperature of the gas at the top of the tower is high (more than 40 ℃), and circulating water can be used as a cooling working medium.

In some embodiments, referring again to fig. 2, a prepolymerization reactor is further provided before the first reactor.

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

In addition, the invention also provides a gas phase polypropylene production process based on the fact that no airlock device is arranged, the process is implemented by adopting the production device, and the process comprises the following steps of:

In some embodiments, when a prepolymerization reactor is further provided before the first reactor, a prepolymerization product obtained by slurry polymerization of propylene, ethylene and hydrogen in the prepolymerization reactor is also fed into the first reactor for further reaction.

The above embodiments may be implemented singly or in any combination of two or more.

The above embodiments are described in more detail below in connection with specific examples.

Example 1:

in combination with the above embodiment and referring to fig. 1, taking a 30 ten thousand ton/year gas phase polypropylene apparatus as an example, the powder productivity during homopolymerization, random copolymerization and impact copolymerization is 40t/h, 37.5t/h and 34.8t/h, respectively, wherein: to control the rubber content and ethylene content of the impact copolymer, the low ethylene impact copolymerization regime had a one-reactor (i.e., first reactor) capacity of 30455kg/h and a two-reactor (i.e., second reactor) capacity of 4345kg/h; the first reaction capacity of the high-ethylene impact copolymerization working condition is 26452kg/h, and the second reaction capacity is 8352kg/h.

Both the first reactor and the second reactor are stirred bed gas phase reactors employing pulsed discharge, with unreacted hydrogen-rich propylene gas entrained in a reaction product typically accounting for about 10% of the fines, wherein: during the low-ethylene impact copolymerization working condition, the primary reaction product entrains 2618kg/h of propylene, which is more than 1908kg/h of the secondary reaction propylene, and at least 710kg/h of propylene needs to be removed from the secondary reaction system through a de-propenizer; the first reverse entrainment hydrogen of the high-ethylene impact copolymerization working condition is 0.25kg/h, the hydrogen demand of the second reverse reaction is more than 0.14kg/h, and at least 0.11kg/h of hydrogen needs to be removed through a dehydrogenation bin system.

1) Low ethylene copolymerization regime:

3000kg/h propylene condensate (ethylene 10.8% and propylene 82.0%) is led from the outlet of the second condensate pump to the de-allyl tower, when the propylene recovery rate at the bottom of the tower is controlled to be 50% and the ethylene content is no more than 10wppm, the condensing temperature at the top of the tower is 42 ℃, the reflux ratio is 0.80, and the tower diameter is calculated to be 911mm. The noncondensable gas (ethylene 21.5 percent and propylene 72.7 percent) at the top of the tower is automatically pressed and returned to the second reactor through a collecting pipe at the outlet of the second circulating compressor; 1499kg/h of propylene (10 wppm of propylene) at the bottom of the column is pumped back to the first reactor through a propylene gasifier and a dehydrogenation silo. The two-shot propylene deficiency (1499-710=789 kg/h) was supplemented by a propylene feed system.

2) High ethylene copolymerization conditions:

about 3000kg/h of gasified propylene is introduced into the lower part of the dehydrogenation bin, the propylene gas (2572 kg/h, wherein 0.25kg/h of hydrogen is contained in the first-reaction product) is diluted, the amount of hydrogen entering the second-reaction from the bottom of the dehydrogenation bin is ensured to be less than that of the second-reaction product (0.14 kg/h), and the insufficient part of the second-reaction hydrogen is supplemented by a hydrogen supply system.

The process conditions of the materials in this example are shown in the following table:

in general, the process flow of the embodiment is suitable for propylene homo-polymerization, random copolymerization and impact copolymerization production, and can realize long-period operation to produce polypropylene products.

The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.

Claims

1. The utility model provides a production facility based on anti-impact polypropylene of dehydrogenation storehouse-depropanization tower, its characterized in that includes first reactor and the second reactor that sets gradually along main material flow direction, still is equipped with the dehydrogenation storehouse between first reactor and second reactor, the second reactor by still be equipped with the depropanization tower of receiving the condensate that its top gaseous phase condensation formed, the top outlet of the tower of depropanization still returns to connect the second reactor, the bottom outlet still returns to connect the dehydrogenation storehouse.

2. The apparatus for producing polypropylene according to claim 1, wherein 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 sequentially lowered.

3. The production device of the impact polypropylene based on the dehydrogenation bin-dealkage tower according to claim 1, wherein the top gas phase outlet of the first reactor is further provided with a first condensation loop with a first condenser, and the top of the dehydrogenation bin is further connected with the first condenser in a return way.

4. The apparatus for producing polypropylene with impact resistance based on dehydrogenation storehouse-dealkage tower according to claim 3, wherein a pressure difference control valve is further arranged between the first reactor and the first condenser, so that the pressures in the first reactor, the dehydrogenation storehouse and the first condenser are sequentially reduced.

5. The production device of the impact polypropylene based on the dehydrogenation bin-deallyzer according to claim 1, wherein a top gas phase outlet of the second reactor is further provided with a second condensation loop with a second condenser and a condensate pump, and the condensate pump is further connected with the deallyzer through a pipeline.

6. The production device of the impact polypropylene based on the dehydrogenation bin-the dealkylation tower according to claim 1, wherein a propylene gasifier is further arranged between the dealkylation tower and the dehydrogenation bin.

7. The apparatus for producing polypropylene with impact resistance based on dehydrogenation silo-deallylation column according to claim 1, wherein the first reactor is further provided with a prepolymerization reactor.

8. The apparatus for producing polypropylene based on dehydrogenation silo-deallyzer according to claim 1, wherein the outlet of the second reactor is further connected with a filter.

9. Process for the production of impact polypropylene based on a dehydrogenation silo-de-propertyion tower, carried out with a production plant according to any of claims 1-8, characterized in that it comprises the following steps:

10. The process for producing polypropylene based on dehydrogenation-tray-deallylation column according to claim 9, wherein when a prepolymerization reactor is further provided before the first reactor, a prepolymerization product obtained by slurry polymerization of propylene, ethylene and hydrogen in the prepolymerization reactor is also fed into the first reactor to continue the reaction.