CN116041587A

CN116041587A - Method and equipment for continuous industrial production of high-isotacticity polybutene-1

Info

Publication number: CN116041587A
Application number: CN202211731152.XA
Authority: CN
Inventors: 逯云峰; 刘汉英; 任合刚; 高晶杰; 曹坚; 陈意心; 安振永
Original assignee: Beijing Petrochemical Engineering Co Ltd; Guangdong University of Petrochemical Technology
Current assignee: Beijing Petrochemical Engineering Co Ltd; Guangdong University of Petrochemical Technology
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-05-02

Abstract

The invention provides a method and equipment for continuously and industrially producing high-isotacticity polybutene-1. The method comprises the following steps: polymerization, polymer separation, monomer recovery, polymer granulation and the like. The apparatus includes: a polymerization unit, a polymer separation unit, a monomer recovery unit, and a polymer pelletization unit. The method and the equipment of the invention are continuous industrial production methods and equipment for preparing the high isotactic polybutene-1 by liquid phase polymerization, and can prepare the high isotactic polybutene-1 with low monomer content.

Description

Method and equipment for continuous industrial production of high-isotacticity polybutene-1

Technical Field

The invention relates to the field of petrochemical industry, in particular to a method and equipment for continuously and industrially producing high-isotacticity polybutene-1.

Background

Polybutene-1 is prepared by polymerizing butene-1 monomer as raw material in the presence of catalyst by slurry method, gas phase method or liquid phase method. It is a semi-crystalline polyolefin thermoplastic resin with good mechanical properties; outstanding environmental stress crack resistance and hot pressure resistance; excellent creep resistance, repeated winding and continuous, and good creep resistance even at elevated temperatures; good resistance to chemical attack; abrasion resistance similar to ultra high molecular weight polyethylene; high filler filling properties, etc. Thus polybutene-1 is useful for the production of pipes, films, sheets, various containers and the like, and in particular it can be used for a long period of time at a temperature of 90-100 ℃.

The existing preparation methods of the high isotactic polybutene-1 mainly comprise a slurry method, a liquid phase method and a gas phase method. The slurry process for producing polybutene-1 is mainly Huels process, US3944529 adopts delta-TiCl ₃ /AlEt ₂ Cl is a catalytic system, isobutane is a reaction medium, H-iPB (with 99.1% isotacticity) is synthesized by slurry polymerization at 50-70 ℃, and the particle size of polybutene-1 is 120 mu m. US5037908 uses TiCl ₄ /MgCl ₂ Dibutyl phthalate/AlEt ₃ Phenyl triethoxy silane catalyst system, isobutane is used as solvent to catalyze butene-1 slurry polymerization to obtain bulk density of 0.30g/cm ³ High isotacticity polybutene-1 with catalytic activity of 2.7kg PB/gcat. The method adopts inert hydrocarbon solvent as reaction medium, and has the characteristics of simple operation, easy derivation of polymerization heat, convenient reaction control and the like; however, the disadvantages are also obvious, and the process of separating inert diluent from unreacted monomers is also faced after the reaction is finished to recover the monomers, so that the boiling points of butene and isobutene are very close, and the separation and refining processes are complex, low in efficiency and high in cost.

Catalyst used for producing polybutene-1 by gas phase method is mostly SiO ₂ Supported Ti-based catalysts, polypropylene active particle catalysts, active poly-4-methyl-1-pentene polymer catalysts, and the like. SiO is used as in US4503203 ₂ The supported Ti-based catalyst is polymerized for 7.8 hours in a fluidized bed to synthesize polybutene-1 with an isotacticity of 95.0 percent, a product particle diameter of 56 mu m and a bulk density of 0.29g/cm ³ However, the catalyst residue in the product is high; in EP0294767A1, polypropylene active particle catalyst is adopted to react in a fluidized bed, so that the isotacticity is 98% and the bulk density is 0.36g/cm ³ Is prepared from high-grade isotactic polybutene-1. In CN1032172A, it is reported that the polymerization of butene-1 is catalyzed by a poly-4-methyl-1-pentene polymer catalyst, the catalyst activity reaches 386kg PB/gTi, the isotacticity of the polymer reaches 99.0%, and the bulk density is 0.41g/cm ³ The chloride content in the product was only 44ppm, and it was found that the use of the active polymer catalyst increased the flowability of the polymer particles, improved the adhesion of the polymer particles to the reactor, and increased the bulk density of the product. But compared with ethylene and propylene, the butene-1 monomer has better affinity for hydrocarbon solvents, so that even if a very small amount of solvent exists in a gas-phase polymerization system, the product can agglomerate, and the whole reaction cannot be stably operated on equipment for a long time, so that the production process of the polybutene-1 by a gas-phase method only exists in the research field and has no industrial production example.

The liquid phase method is to catalyze the polymerization of butene-1 by using liquid phase butene-1 monomer or hydrocarbon organic compound as solvent or reaction medium under the action of catalyst, and is classified into homogeneous solution method, homogeneous bulk method and heterogeneous bulk method according to the product form of polybutene-1. US3944529 uses an inert solvent for isobutene as the diluentThe releasing agent is subjected to solution polymerization, n-hexane is adopted as a solvent in US5237013, so that butene-1 solution polymerization is realized, and isotactic polybutene-1 with the isotactic content of more than 94% is obtained; CN1590417a adopts a metallocene catalyst solution polymerization method to synthesize isotactic polybutene-1 with isotacticity of above 96%. The inert hydrocarbon solvent is adopted as a reaction medium, so that the method has the characteristics of simplicity and convenience in operation, easiness in derivation of polymerization heat, convenience in reaction control and the like; however, the disadvantages are also obvious, and the solution polymerization is that the polybutene-1 swells and dissolves in the monomer, so that the system is sticky, and mass transfer and heat transfer are difficult, which limits the polymerization process to be stopped at low conversion or further improves the conversion and removes unreacted monomers by adopting a reaction extrusion technology. Meanwhile, the process of separating inert diluent from unreacted monomers is also faced, the production efficiency is reduced, and the complexity and the production cost of the production process are increased. In order to avoid the complex process and high cost caused by the separation of inert solvent and monomer, CN101020728A adopts a bulk precipitation method to prepare high isotactic polybutene-1, overcomes the defect that solvent recovery and post-treatment are needed in a solution method, but the technology only discloses a synthesis method and material for bulk precipitation polymerization of polybutene-1, and does not relate to a production method, a process flow, implementation equipment and the like of industrial production. CN103897080A discloses a process for preparing high-isotatic polybutene-1 and apparatus for carrying out the process, which comprises, subjecting liquid butene-1 monomer to bulk polymerization in a polymerization vessel at-10deg.C to 70deg.C in the presence of supported Ti-based catalyst to prepare high-isotatic polybutene-1, subjecting part of unreacted butene-1 to pressure reduction to recover into butene-1 gas holder after polymerization for 3-6h, transferring high-isotatic polybutene-1 from the polymerization vessel to flash evaporation vessel, subjecting the obtained product to pressure reduction flash evaporation, recovering unreacted butene-1 monomer into butene-1 gas holder, charging nitrogen and air into the flash evaporation vessel successively for replacement, discharging and packaging granular high-isotatic polybutene-1 product with bulk density of at most 0.418g/cm through a bottom discharge valve ³ The highest catalyst activity was 2666 gPB/(gcat.h), but the ash content of the product was higher. CN105482009a discloses a continuous process for producing polybutene-1, comprising prepolymerization, slurryPolymerizing, gas phase polymerizing, gas-solid separating and other steps to obtain polybutene-1 powder. The process comprises the steps of adding metered butene-1 serving as a raw material, a titanium catalyst, an alkyl aluminum cocatalyst, a silane electron donor and a hydrogen molecular weight regulator into a prepolymerization kettle, performing prepolymerization for 5-15 minutes, then entering a slurry polymerization reaction kettle, performing slurry polymerization for 3-5 hours at 25-55 ℃ and 0.6-1.6MPa, then entering slurry polymerized slurry into a gas phase horizontal reaction kettle by means of pressure difference, performing gas phase polymerization for 3-5 hours at 30-60 ℃ and 0.5-1.5MPa, and condensing and sending gasified butene-1 back to the gas phase horizontal reaction kettle through a condenser; finally, the slurry obtained by gas phase polymerization enters a receiving tank, decompression is carried out, polybutene-1 powder is obtained by separation, and the butene-1 gas is filtered and washed, condensed into liquid and then sent to a prepolymerization reactor for recycling. Although the heterogeneous liquid phase bulk method polybutene-1 has simple production process, when the polymerization temperature is higher than 30 ℃, the polybutene-1 swells in the monomer, so that the system is sticky, heat transfer and mass transfer are difficult, the reaction temperature of each section needs to be strictly controlled, the reaction time is longer, the production efficiency is lower, and the product quality is difficult to ensure.

US3944529, US6306996 disclose a liquid phase bulk polymerization process using a titanium based catalyst system comprising an electron donor, butene-1 monomer as reaction medium, resulting in polybutene-1 having an isotactic content of more than 99% under optimized conditions, the catalyst activity being 14000gPB/gcat. CN106832070a discloses a continuous production method of polybutene-1. The production method comprises the steps of taking 1-butene monomer as a raw material to carry out polymerization reaction in the presence of a catalyst, an auxiliary agent and the like, removing a mixture containing unreacted 1-butene monomer from a reaction material to obtain polybutene-1, wherein the auxiliary agent is dissolved in a solvent in advance before being added into a polymerization reactor, recovering the solvent from the mixture containing unreacted 1-butene monomer, rectifying and separating an obtained first tower bottom component, carrying out liquid-liquid extraction and cleaning on an obtained second tower top component, and obtaining a recovered solvent, wherein the recovered solvent is returned to dissolve the auxiliary agent, so that the influence of the solvent on a product due to the addition of the auxiliary agent in the polymerization process is solved, however, the process is incomplete for deashing the product, the yellowing of the product is caused, and the product quality is difficult to ensure.

The prior art only discloses polymerization synthesis methods, materials and recovery processes of a butene-1 bulk homogeneous phase method, and few documents relate to production methods, process flows, implementation equipment and the like of industrial production of polybutene-1, in particular to methods and equipment of a devolatilization process of products after polymerization of butene-1. Therefore, the development of a novel method and equipment for continuously and industrially producing high-isotacticity polybutene-1 becomes one of the problems to be solved in the field.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a method and equipment for continuously and industrially producing high-isotacticity polybutene-1. The method and the equipment of the invention are continuous industrial production methods and equipment for preparing the high isotactic polybutene-1 by liquid phase polymerization, and can prepare the high isotactic polybutene-1 with low monomer content.

In order to achieve the above object, the first aspect of the present invention provides a method for continuously and industrially producing highly isotactic polybutene-1, comprising the steps of:

(1) Polymerization: in a polymerization kettle, taking a monomer containing liquid butene-1 as a raw material, and carrying out polymerization reaction in the presence of a catalyst system to obtain a polymer solution;

(2) Polymer separation: allowing the polymer solution to flow out of the polymerization kettle, then entering a deactivation tank, and mixing with a terminator to deactivate the catalyst; then, the pressure is increased to a first pressure, the temperature is increased to a first temperature, the mixture enters a first demonomerization tower for monomer removal, polybutene-1 melt after the first demonomerization is obtained, the polybutene-1 melt is discharged from the first demonomerization tower, the mixture is heated to a second temperature, the mixture enters a second demonomerization tower for monomer removal under a second pressure, polybutene-1 melt after the second demonomerization is obtained, and separated gas containing monomers flows out from the first demonomerization tower and the second demonomerization tower;

(3) Monomer recovery: enabling the monomer-containing gas flowing out of the first monomer removal tower and the second monomer removal tower to enter a monomer recovery unit for recovery to obtain monomer gas;

(4) Granulating a polymer: extruding and granulating the polybutene-1 melt subjected to the second monomer removal to obtain the high isotacticity polybutene-1.

In the above-described method, preferably, in step (1), the liquid butene-1-containing monomer may further comprise an α -olefin comonomer; more preferably, the alpha-olefin comonomer comprises a C2-C10 alpha-olefin; further preferably, the alpha-olefin comonomer may comprise ethylene and/or propylene, and the like.

In the above process, preferably, in step (1), the catalyst system comprises a procatalyst, a cocatalyst and an external electron donor compound.

In step (1), more preferably, the main catalyst includes a titanium-based solid catalyst, such as, but not limited to, a magnesium halide-supported titanium-based solid catalyst and/or a magnesium alkoxide-supported titanium-based solid catalyst, and the like. Further preferably, the main catalyst is used in an amount of: 30000-140000g of liquid butene-1/g of main catalyst. The magnesium halide supported titanium solid catalyst can be selected from various magnesium halide supported titanium solid catalysts disclosed in the prior art, takes magnesium halide or magnesium halide alcohol compound as a carrier, takes Ti as an active component and can also be selectively loaded with an internal electron donor compound, wherein the internal electron donor compound can comprise one or a combination of more of carboxylic acid esters, ethers, succinic acid esters, 1, 3-alcohol esters, sulfonamide compounds and the like; such as spherical magnesium chloride (or anhydrous magnesium chloride) supported titanium-based solid catalysts. The alkoxy magnesium supported titanium solid catalyst can be various alkoxy magnesium supported titanium solid catalysts disclosed in the prior art, takes alkoxy magnesium or alkoxy magnesium alcohol compound as a carrier, takes Ti as an active component and can also be selectively loaded with an internal electron donor compound, wherein the types of the internal electron donor compound are as described above; such as magnesium ethoxide supported titanium-based solid catalysts.

In step (1), more preferably, the cocatalyst may comprise an alkyl aluminum compound; more preferably, the cocatalyst comprises one or a combination of several of triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum and the like; further preferably, the alkyl aluminum compound is triethylaluminum. Further preferably, the cocatalysts are used in an amount of: 850-14000g liquid butene-1/g cocatalyst.

In step (1), more preferably, the external electron donor compound may include an alkoxysilane compound; further preferably, the external electron donor compound includes one or a combination of several of dicyclopentyl dimethoxy silane, cyclohexylmethyl dimethoxy silane, dicyclohexyl dimethoxy silane, cyclohexyltriethoxy silane, methyltriethoxy silane, methylcyclopentyl dimethoxy silane, isobutyl isopropyl dimethoxy silane, isopropyl cyclopentyl dimethoxy silane, isobutyl triethoxy silane, and the like. Further preferably, the external electron donor compound is used in an amount of: 40000-250000g of liquid butene-1/g of external electron donor compound.

In the above-mentioned method, preferably, in the step (1), the polymerization reaction is carried out in the presence of hydrogen and an inert gas. Hydrogen may be used as a molecular weight regulator. More preferably, the hydrogen is used in an amount of: 1500-300000g liquid butene-1/g hydrogen. Inert gases may be used as shielding gas and pressurizing gas. More preferably, the inert gas comprises nitrogen.

In the above-mentioned method, preferably, in the step (1), the polymerization reaction is carried out at a temperature of 50 to 80℃and a reaction pressure of 2.0 to 2.5MPa for a reaction time of 2 to 5 hours. More preferably, the polymerization reaction temperature is 65-75deg.C, the reaction pressure is 2.0-2.2MPa, and the reaction time is 3-4 hours.

In the above method, preferably, in the step (1), the polymer concentration by weight in the polymer solution is 20 to 25%.

In the above method, preferably, step (1) further includes: the monomer, and/or the catalyst system, and/or the hydrogen, and/or the inert gas are fed into the polymerizer via a metering device, respectively.

In the above method, preferably, step (1) further includes: the raw material butene-1 from the outside is refined and then enters the polymerization kettle. The refining can be performed by using a refining system conventional in the art to remove impurities such as trace water and oxygen present in the raw material butene-1 so that the content of impurities such as water and oxygen in the raw material butene-1 is 2ppm or less.

In step (2) of the above method, the deactivation pot may be a stirred tank apparatus or a static mixer. The terminator may be a polymerization terminator conventional in the art, such as, but not limited to, water, oxygen, carbon dioxide, carbon monoxide or alcohols, etc., and may be used in an amount of 0.1 to 1.0% by weight of the polymer solution. After the polymerization reaction, the active center in the polymer solution is deactivated by adopting a mode of adding the terminator, the polymerization reaction is effectively stopped, and the problem of continuous polymerization or explosion polymerization in the subsequent treatment process is prevented.

In the above method, preferably, in step (2), the first pressure is 2.8 to 3.2MPa and the first temperature is 195 to 205 ℃. More preferably, step (2) comprises: the polymer solution flowing out of the deactivation pot is pressurized to the first pressure by a pump, and then the pressurized polymer solution is heated to the first temperature by a heat exchanger. More specifically, the pump includes a gear pump or a screw pump, preferably a gear pump.

In the above method, preferably, in step (2), the second temperature is 205 to 215 ℃, and the second pressure is 0.001 to 0.003MPa. More preferably, step (2) comprises: and heating the polybutene-1 melt subjected to the first demonomerization to the second temperature by adopting a heat exchanger, then entering a second demonomerization tower, and controlling the operating pressure of the second demonomerization tower at the second pressure by adopting a vacuum pump arranged outside the tower top of the second demonomerization tower.

In the above-mentioned method, preferably, in the step (2), the content of the monomer (mainly butene-1) in the polybutene-1 melt after the second time of the demonomerization is 35ppm by weight or less.

In the above method, preferably, in step (2), the tower bodies of the first monomer removal tower and the second monomer removal tower are internally provided with a plurality of layers of conical surfaces in the vertical direction, and the plurality of layers of conical surfaces comprise a downward opening dispersion surface and an upward opening receiving surface which are adjacently arranged in the vertical direction; the tower top is provided with a feed inlet and a gas outlet; the bottom of the tower is provided with a discharge hole. More preferably, the cone angle of the conical surfaces of the layers is 130 ° -150 °. More preferably, the number of conical surfaces inside the tower body is an odd number of 5-9, and the first layer of conical surfaces in the vertical direction are dispersion surfaces with downward openings. Further preferably, the number of conical surfaces inside the tower body is seven, and the first conical surface in the vertical direction is a dispersion surface with a downward opening. More preferably, the side walls of the first and second demonomerization towers may be provided with sight glass, respectively.

In a specific embodiment of the invention, after the catalyst deactivation is carried out on the polymer solution from a polymerization kettle, the pressure is increased by adopting a pump, after the temperature is increased by adopting a heat exchanger, the polymer solution reaches the operating pressure and the temperature of a first demonomerization tower, then the polymer solution enters the first demonomerization tower for monomer removal, in the first demonomerization tower, the polymer solution is flatly paved and thinned through a plurality of layers of conical surfaces arranged in the tower under the action of gravity, so that the monomer (mainly butene-1 gas) and the melted polybutene-1 are fully separated, the polybutene-1 melt is settled to the bottom of the first demonomerization tower and is discharged from a discharge hole at the bottom of the tower by virtue of the pump, and the gas containing the monomer flows out from a gas outlet at the top of the tower; and then heating the polybutene-1 melt subjected to the first monomer removal to the operation temperature in a second monomer removal tower by adopting a heat exchanger, entering the second monomer removal tower, controlling the operation pressure of the second monomer removal tower in a vacuum state by adopting a vacuum pump arranged outside the tower top of the second monomer removal tower, removing the monomers to obtain the polybutene-1 melt subjected to the second monomer removal, discharging the polybutene-1 melt from a discharge port at the tower bottom by virtue of the pump, and discharging the gas containing the monomers from a gas outlet at the tower top.

In the above-mentioned method, preferably, in step (3), the monomer recovery unit includes at least a separation column; the step (3) comprises: the monomer-containing gas flowing out of the first and second monomer removal towers is separated by at least a separation tower, and then the monomer gas and the terminator are separated.

In the above method, preferably, in step (3), the monomer recovery unit further comprises a buffer tank; step (3) further comprises: the monomer-containing gas flowing out of the first monomer removing tower and the second monomer removing tower is respectively passed through a buffer tank and then enters a separation tower for separation.

In the above-mentioned method, preferably, in step (3), the monomer recovery unit further comprises one or a combination of several of a condenser, a scrubber and a drying tower; step (3) further comprises: and (3) processing the monomer gas separated by the separation tower through one or a combination of condensation, washing and drying to obtain the processed monomer. The sequence of the condensation, washing and drying is not particularly limited in the present invention, and can be adjusted conventionally by those skilled in the art.

In the above method, preferably, in step (3), the monomer recovery unit further includes a monomer tank; step (3) further comprises: and enabling the treated monomer to enter the monomer storage tank for storage. More specifically, the monomer storage tank may be a liquid butene-1 storage tank.

In the above method, preferably, step (3) further includes: and (3) enabling the treated monomer or the monomer stored in the monomer storage tank to enter a polymerization kettle in the step (1) for recycling.

In the above method, preferably, step (3) further includes: and (3) enabling the terminator separated by the separation tower to enter a deactivation pot in the step (2) for recycling.

In the above method, preferably, in step (4), the extrusion is performed using a screw extruder, and more preferably, the screw extruder is provided with a vacuum degassing device. The vacuum degasser includes, but is not limited to, a vacuum pump. More preferably, step (4) further comprises: in the process that the polybutene-1 melt after the second monomer removal is extruded by a screw extruder, the residual monomer (mainly butene-1) is further removed by a vacuum degassing device of the screw extruder. More preferably, step (4) further comprises: and adding an additive in the process of extruding the polybutene-1 melt subjected to the second monomer removal by a screw extruder to obtain a mixture of the polybutene-1 and the additive, and granulating. The additives may be additives conventionally used in the art, such as light stabilizers, antioxidants, colorants, fillers, and the like.

In the above method, preferably, in step (4), the granulating is performed using an underwater pelletizer.

In a second aspect, the present invention provides an apparatus for continuous industrial production of highly isotactic polybutene-1 for realizing the above-mentioned method for continuous industrial production of highly isotactic polybutene-1, comprising: a polymerization unit, a polymer separation unit, a monomer recovery unit, and a polymer granulation unit;

the polymerization unit comprises a polymerization kettle, and the polymerization kettle is at least provided with a reaction system inlet and a polymer solution outlet;

the polymer separation unit comprises a deactivation pot, a booster pump, a first heat exchanger, a first demonomerization tower, a second heat exchanger, a second demonomerization tower and a vacuum pump; the deactivation pot is provided with at least a polymer inlet, a terminator inlet and a discharge port; the first monomer removing tower and the second monomer removing tower are at least respectively provided with a feed inlet, a gas outlet and a discharge outlet;

the polymer granulating unit comprises an extruder and a granulator;

the polymer solution outlet of the polymerization kettle is connected with the polymer inlet of the deactivation tank through a pipeline; the discharge port of the deactivation tank is connected with the feed port of the first monomer removal tower through a pipeline, a booster pump and a first heat exchanger; the discharge port of the first monomer removal tower is connected with the feed port of the second monomer removal tower through a pipeline and a second heat exchanger, and the vacuum pump is connected with the gas outlet of the second monomer removal tower through a pipeline;

The gas outlet of the first monomer removal tower is connected with the monomer recovery unit through a pipeline; the gas outlet of the second monomer removal tower is connected with the monomer recovery unit through a pipeline and the vacuum pump;

and the discharge port of the second monomer removal tower is sequentially connected with the extruder and the granulator through pipelines.

In the above apparatus, preferably, the reaction system inlet of the polymerizer comprises: a monomer inlet, a catalyst system inlet, a hydrogen inlet, and an inert gas inlet; more preferably, the monomer inlet comprises a liquid butene-1 inlet and optionally an alpha-olefin comonomer inlet.

In the above-mentioned apparatus, the polymerization vessel may be a polymerization vessel conventional in the art, and may be provided with a stirring device inside, and the present invention is not limited to the specific structure thereof.

In the above-described apparatus, preferably, the polymerization unit further comprises one or several meters for introducing the monomers, and/or the catalyst system, and/or hydrogen, and/or the inert gas, respectively, into the polymerization vessel through the meters.

In the above apparatus, preferably, the polymerization unit further includes: and the refining system is communicated with the monomer inlet of the polymerization kettle and is used for refining raw material butene-1 from the outside. The refining system can adopt a refining system conventional in the field to remove trace water, oxygen and other impurities in the raw material butene-1 so as to ensure that the content of the water, oxygen and other impurities in the raw material butene-1 is below 2 ppm.

In the above-mentioned apparatus, the deactivation pot may be a stirred tank apparatus or a static mixer, which may employ a conventional mixing device in the art, and the present invention is not limited to the specific structure thereof.

In the above apparatus, preferably, a plurality of layers of conical surfaces are provided in the vertical direction inside the bodies of the first and second monomer removal towers, and each layer of conical surface includes a downward opening dispersion surface and an upward opening receiving surface that are adjacently provided in the vertical direction; the tower top is provided with the feed inlet and the gas outlet; the bottom of the tower is provided with the discharge hole. More preferably, the cone angle of the conical surfaces of the layers is 130 ° -150 °. More preferably, the number of conical surfaces inside the tower body is an odd number of 5-9, and the first layer of conical surfaces in the vertical direction are dispersion surfaces with downward openings. Further preferably, the number of conical surfaces inside the tower body is seven, and the first conical surface in the vertical direction is a dispersion surface with a downward opening. More preferably, the side walls of the first and second demonomerization towers may be provided with sight glass, respectively. The structures of the first and second demonomerization towers of the present invention may be identical or different, as long as the above-described limitations of the present invention are met.

In the above-described apparatus, preferably, the booster pump includes a gear pump or a screw pump, more preferably a gear pump.

In the above apparatus, preferably, the first heat exchanger and the second heat exchanger each comprise a multi-tube heat exchanger.

In the above apparatus, preferably, the discharge port of the first demonomerization tower is provided with a transfer pump for discharging the bottom material from the discharge port and transferring to the second heat exchanger. More specifically, the transfer pump comprises a gear pump or screw pump, preferably a gear pump.

In the above apparatus, preferably, the discharge port of the second demonomerization tower is provided with a transfer pump for discharging the bottom material from the discharge port and transferring it to the extruder. More specifically, the transfer pump comprises a gear pump or screw pump, preferably a gear pump.

In the above-described apparatus, preferably, the monomer recovery unit includes at least a separation column provided with a material inlet, a monomer gas outlet, and a terminator outlet; the gas outlet of the first demonomerization tower is connected with the material inlet of the separation tower through a pipeline, and the gas outlet of the second demonomerization tower is connected with the material inlet of the separation tower through a pipeline and the vacuum pump; the monomer-containing gas flowing out of the first and second monomer removal towers is separated by at least a separation tower, and then the monomer gas and the terminator are separated.

In the above apparatus, preferably, the monomer recovery unit further includes buffer tanks respectively provided on a line connecting the gas outlet of the first demonomerization tower with the separation tower, and a line connecting the outlet of the vacuum pump outside the second demonomerization tower with the separation tower; the gas containing monomer which flows out of the first monomer removing tower and the second monomer removing tower firstly passes through the buffer tank respectively and then enters the separation tower for separation.

In the above-described apparatus, preferably, the monomer recovery unit further includes one or a combination of several of a condenser, a scrubber and a drying tower; one or more combinations of a condenser, a scrubber and a drying tower are arranged at the rear part of the separation tower and are used for processing the monomer gas separated by the separation tower through one or more combinations of condensation, washing and drying to obtain the processed monomer. The present invention is not particularly limited to the front and rear positions of the condenser, the scrubber and the drying tower, and may be routinely adjusted by those skilled in the art.

In the above-described apparatus, preferably, the monomer recovery unit further includes a monomer storage tank provided behind one or a combination of several of the condenser, the scrubber, and the drying tower for storing the treated monomer. More preferably, the monomer storage tank may be a liquid butene-1 storage tank.

In the above apparatus, preferably, the monomer recovery unit further includes a monomer circulation line having one end connected to a reaction system inlet (monomer inlet) of the polymerizer and the other end connected to an outlet of the scrubber, or an outlet of the condenser, or an outlet of the drying tower, or an outlet of the monomer storage tank; is used for recycling the monomer.

In the above apparatus, preferably, the monomer recovery unit further includes a terminator circulation line having one end connected to a terminator inlet of the deactivation tank and the other end connected to a terminator outlet of the separation column for recycling the terminator separated by the separation column.

In the above apparatus, preferably, the extruder comprises a screw extruder; more preferably, the screw extruder has a vacuum degasser. The vacuum degasser includes, but is not limited to, a vacuum pump.

In the above apparatus, preferably, the pelletizer includes an underwater pelletizer.

The invention provides a method and equipment for continuously and industrially producing high-isotacticity polybutene-1, in particular to a continuous industrial production method and equipment for preparing high-isotacticity polybutene-1 by liquid phase polymerization. The method and the equipment of the invention comprise a technological method and a device for removing monomers (devolatilization) of the polymerized product, which complement the blank of the prior art; meanwhile, the method takes the liquid butene-1 monomer as a reaction medium, has no solvent removal process, and has the advantages of simple flow, easy operation, high monomer recovery efficiency, high polymer product quality, stable equipment operation and the like; therefore, the method and the equipment can continuously and industrially produce the high-isotacticity polybutene-1 to prepare the high-isotacticity polybutene-1 with low monomer content.

The method and the equipment for continuously and industrially producing the high-isotacticity polybutene-1 have at least the following beneficial technical effects:

(1) According to the technical scheme, unreacted butene-1 can be effectively removed from a polymer containing butene-1 monomers, the butene-1 monomers and the molten polybutene-1 are efficiently and fully separated through the two demonomerization towers with a plurality of conical surfaces arranged inside, and the residual butene-1 is further removed by adopting a screw extruder with a vacuum degassing device for treatment, so that the monomer content in a polymer product is finally less than 35ppm, even less than 30ppm, and the problem of explosiveness caused by the release of butene-1 in finished polymer particles is remarkably reduced;

(2) The technical scheme of the invention adopts the liquid butene-1 monomer as a reaction medium, has no solvent removal process, has the advantages of simple flow, easy operation, high monomer recovery efficiency, high heat removal efficiency, stable operation and the like, and simultaneously has the advantages of high production capacity, high catalyst utilization rate, balanced polymer product granule discharging speed, uniform size, full appearance, high quality and the like.

Drawings

FIG. 1 is a schematic structural view of an apparatus for continuous industrial production of highly isotactic polybutene-1 according to one embodiment of the present invention.

Reference numerals illustrate: 1-polymerizer, 2-catalyst system mixer, 3-refining system, 4-deactivation tank, 5-booster pump, 6-first heat exchanger, 7-first monomer removal column, 71-conical surface, 711-dispersion surface, 712-receiving surface, 8-first transfer pump, 9-second heat exchanger, 10-second monomer removal column, 11-second transfer pump, 12-vacuum pump, 13-first buffer tank, 14-second buffer tank, 15-separation column, 16-drying column, 17-condenser, 18-monomer storage tank, 19-screw extruder, 191-vacuum degassing device, 20-underwater pelletizer.

Detailed Description

The technical solution of the present invention will be described in detail below for a clearer understanding of technical features, objects and advantageous effects of the present invention, but should not be construed as limiting the scope of the present invention.

Example 1

The embodiment provides a device for continuously and industrially producing high-isotacticity polybutene-1, the structure of which is shown in figure 1, and the device comprises: a polymerization unit, a polymer separation unit, a monomer recovery unit, and a polymer granulation unit;

the polymerization unit comprises a polymerization kettle 1, a catalyst system mixer 2 and a refining system 3;

the polymerization kettle 1 is at least provided with a reaction system inlet and a polymer solution outlet; the reaction system inlet comprises a monomer inlet, a catalyst system inlet, a hydrogen inlet and an inert gas inlet;

The catalyst system mixer 2 is connected to the catalyst system inlet of the polymerization kettle 1 through a pipeline;

the refining system 3 is communicated with a monomer inlet of the polymerization kettle 1 and is used for refining raw material butene-1 from the outside;

the polymerization unit further comprises one or several meters (not shown in fig. 1) for letting monomers, and/or catalyst systems, and/or hydrogen, and/or inert gases, respectively, pass through the meters into the polymerization vessel 1;

the polymer separation unit comprises a deactivation pot 4, a booster pump 5, a first heat exchanger 6, a first demonomerization tower 7, a first delivery pump 8, a second heat exchanger 9, a second demonomerization tower 10, a second delivery pump 11 and a vacuum pump 12; the deactivation pot 4 is provided with at least a polymer inlet, a terminator inlet and a discharge port; the first monomer removing tower 7 and the second monomer removing tower 10 are at least respectively provided with a feed inlet, a gas outlet and a discharge outlet;

the monomer recovery unit comprises a first buffer tank 13, a second buffer tank 14, a separation tower 15, a drying tower 16, a condenser 17 and a monomer storage tank 18; the separation tower 15 is provided with a material inlet, a monomer gas outlet and a terminator outlet;

the polymer pelletization unit includes a screw extruder 19 having a vacuum degasser 191 and an underwater pelletizer 20; wherein the vacuum degasser 191 is a vacuum pump;

The polymer solution outlet of the polymerization kettle 1 is connected with the polymer inlet of the deactivation pot 4 through a pipeline; the discharge port of the deactivation pot 4 is connected with the feed port of the first monomer removal tower 7 through a pipeline, a booster pump 5 and a first heat exchanger 6; the discharge port of the first demonomerization tower 7 is connected with the feed port of the second demonomerization tower 10 through a pipeline, a first delivery pump 8 and a second heat exchanger 9, and the vacuum pump 12 is connected with the gas outlet of the second demonomerization tower 10 through a pipeline; the discharge port of the second monomer removal tower 10 is connected with the feed port of the screw extruder 19 with the vacuum degassing device 191 through a pipeline and a second delivery pump 11; the discharge port of the screw extruder 19 with the vacuum degasser 191 is communicated with the underwater pelletizer 20;

the gas outlet of the first demonomerization tower 7 is connected with the inlet of the first buffer tank 13 through a pipeline, the gas outlet of the second demonomerization tower 10 is connected with the inlet of the second buffer tank 14 through a pipeline and a vacuum pump 12, the outlets of the first buffer tank 13 and the second buffer tank 14 are connected with the material inlet of the separation tower 15 through pipelines, the monomer gas outlet of the separation tower 15 is sequentially connected with the drying tower 16 and the condenser 17 through a pipeline, the outlet of the condenser 17 is connected with the inlet of the monomer storage tank 18, the outlet of the monomer storage tank 18 is connected with the monomer inlet of the polymerization kettle 1 through a monomer circulation pipeline, and the terminator outlet of the separation tower 15 is connected with the terminator inlet of the deactivation tank 4 through a terminator circulation pipeline;

Wherein the structures of the first demonomerization tower 7 and the second demonomerization tower 10 are completely the same; the tower bodies of the first monomer removal tower 7 and the second monomer removal tower 10 are internally provided with seven layers of conical surfaces 71 in the vertical direction, the seven layers of conical surfaces 71 comprise a downward opening dispersion surface 711 and an upward opening receiving surface 712 which are adjacently arranged in the vertical direction, the first layer of conical surfaces 71 in the vertical direction are downward opening dispersion surfaces 711, and the cone angles of the seven layers of conical surfaces 71 are 135 degrees; the tower top is provided with the feed inlet and the gas outlet; the bottom of the tower is provided with the discharge hole; the side wall of the tower body can be provided with a sight glass;

wherein the booster pump 5 is a gear pump;

wherein the first heat exchanger 6 and the second heat exchanger 9 are multi-tube heat exchangers;

wherein, the first delivery pump 8 and the second delivery pump 11 are gear pumps.

Example 2

The present example provides a method for continuous industrial production of highly isotactic polybutene-1, which uses the apparatus provided in example 1 of example 5 to conduct continuous industrial production of highly isotactic polybutene-1, comprising the steps of:

(1) Polymerization:

the raw material butene-1 from the outside is sent to a refining unit 3 for refining after being metered, so as to remove trace water, oxygen and other impurities in the raw material butene-1, so that the content of the water, the oxygen and other impurities in the raw material butene-1 is less than 2ppm, the purity meets the polymerization requirement, and then the refined butene-1 enters a polymerization kettle 1;

0 in a polymerizer, 4160kg of refined liquid butene-1 monomer as a raw material was added, and a catalyst system comprising 0.07kg of a conventional spherical anhydrous magnesium chloride-supported titanium-based solid catalyst (7 kg of a catalyst solution in which the solid content was 1% by weight was hexane), 2.8kg of triethylaluminum and 0.035kg of dicyclopentyl dimethoxy silane were added to the polymerizer 1 after mixing in a catalyst system mixer 2, the same as

Adding 0.018kg of hydrogen, then maintaining the reaction pressure at 2.1MPa with nitrogen, and carrying out polymerization at 70 ℃ for 3.55 hours, wherein the polymer concentration of the polymer solution in the polymerization kettle is maintained to be 20% by weight;

(2) Polymer separation:

the polymer solution flows out of the polymerization kettle 1 and enters a deactivation tank 4, and is mixed with a terminator to deactivate the catalyst; the polymer solution flowing out of the deactivation pot 4 was then fed to a booster pump 5 to be boosted to 3.0MPa, and recovered

Heating to 200deg.C by a first heat exchanger 6 to make the polymer solution reach the operation pressure and temperature of a first demonomerization tower 7, feeding 0 into the first demonomerization tower 7 for monomer removal, in the first demonomerization tower 7, the polymer solution is flatly laid and thinned by means of gravity through seven layers of conical surfaces 71 (including a dispersing surface 711 and a receiving surface 712) arranged in the tower, so as to fully separate butene-1 gas and molten polybutene-1, the polybutene-1 melt is settled to the bottom of the first demonomerization tower 7 and discharged from a discharge hole at the bottom of the tower by a first conveying pump 8, and the gas containing monomers flows from a gas outlet at the top of the tower

Discharging; then, the polybutene-1 melt after the first demonomerization is heated to the operation temperature in the second demonomerization tower 5 by adopting a second heat exchanger 9, enters the second demonomerization tower 10, the operation pressure of the second demonomerization tower 10 is controlled in a vacuum state by adopting a vacuum pump 12 arranged outside the tower top of the second demonomerization tower 10, monomer removal is carried out under the vacuum condition of 210 ℃ and 0.002MPa, the polybutene-1 melt after the second demonomerization is obtained, and is discharged from a discharge hole at the tower bottom by adopting a second conveying pump 11, and the gas containing the monomers flows out from a gas outlet at the tower top; the butene-1 content in the polybutene-1 melt after the second demonomerization is 30ppm by weight;

(3) Monomer recovery:

the monomer-containing gas flowing out of the first demonomerization tower 7 and the second demonomerization tower 10 respectively pass through a first buffer tank 13 and a second buffer tank 14 and then enter a separation tower 15 for separation, and butene-1 gas and a terminator are separated; the butene-1 gas flowing out from the monomer gas outlet at the top of the separation tower 15 is processed by a drying tower 16 and a condenser 17 and then enters a monomer storage tank 18 of liquid butene-1; feeding the liquid butene-1 stored in the monomer storage tank 18 into the polymerizer 1 in the step (1) for recycling; enabling the terminator flowing out of the terminator outlet at the top of the separation tower 15 to enter the deactivation pot 4 in the step (2) for recycling;

(4) Granulating a polymer:

discharging the polybutene-1 melt subjected to the second monomer removal from a discharge hole at the bottom of a tower by a second conveying pump 11, and then feeding the polybutene-1 melt into a screw extruder 19 with a vacuum degassing device 191, wherein during the extrusion process of the polybutene-1 melt subjected to the second monomer removal by the screw extruder 19, residual butene-1 is further removed by the vacuum degassing device 191 of the screw extruder 19, and additives are added during the extrusion process, so as to obtain a mixture of polybutene-1 and the additives, wherein the additives are 1010 of 1.6kg, 1076 of 1.8kg and 168 of 1.4 kg; the mixture of polybutene-1 and additives discharged from the discharge port of the screw extruder 19 is fed to the underwater pelletizer 20 to be cut into pellets, to obtain the highly isotactic polybutene-1.

The results of this example were obtained by detection: the catalyst activity was 16000gPB/gcat, the isotacticity of the product polybutene-1 was 98.5%, the melt flow rate was 0.6g/10min, and the density was 0.930g/cm ³ Tensile strength 29MPa, nominal strain 300%, and Izod impact strength (23 ℃) 42kJ/m ² 。

Comparative example 1

This comparative example provides a process for the continuous industrial production of highly isotactic polybutene-1 comprising the steps substantially identical to those of example 2, except that: in the step (2), the polymer solution flowing out of the deactivation pot 4 is fed into a booster pump 5 and boosted to 4.0MPa, then the temperature of the polymer solution is raised to 180 ℃ by adopting a first heat exchanger 6, the polymer solution reaches the operating pressure and temperature of a first demonomerization tower 7, then the polymer solution enters the first demonomerization tower 7 for monomer removal, polybutene-1 melt is settled to the bottom of the first demonomerization tower 7 and discharged from a discharge hole at the bottom of the tower by a first delivery pump 8, and gas containing monomers flows out from a gas outlet at the top of the tower; and then, heating the polybutene-1 melt subjected to the first monomer removal to the operation temperature in the second monomer removal tower 10 by adopting a second heat exchanger 9, entering the second monomer removal tower 10, controlling the operation pressure of the second monomer removal tower 10 in a vacuum state by adopting a vacuum pump 12 arranged outside the top of the second monomer removal tower 10, and carrying out monomer removal under the vacuum condition of 190 ℃ and 0.010MPa to obtain the polybutene-1 melt subjected to the second monomer removal, discharging the polybutene-1 melt from a discharge hole at the bottom of the tower by adopting a second conveying pump 11, and discharging the monomer-containing gas from a gas outlet at the top of the tower.

The butene-1 content in the polybutene-1 melt after the second demonomerization was found to be 89ppm by weight.

Comparative example 2

This comparative example provides an apparatus for continuous industrial production of highly isotactic polybutene-1, which is substantially the same as that of example 1 except that: both the first demonomerization column 7 and the second demonomerization column 10 are replaced with devolatilization devices conventional in the art, such as conventional flash tanks.

The present comparative example also provides a method for continuously producing highly isotactic polybutene-1 in an industrial manner using the apparatus provided in the present comparative example, comprising the same steps as those of example 2, and the operating pressures and temperatures of the two devolatilization apparatuses of the present comparative example are also the same as those of the first and second devolatilization towers 7 and 10 of example 2, respectively.

The content of butene-1 in the polybutene-1 melt after the treatment by the second devolatilization apparatus was found to be 112ppm by weight.

Claims

1. A method for continuous industrial production of highly isotactic polybutene-1, comprising the steps of:

2. The continuous industrial process for producing highly isotactic polybutene-1 of claim 1, wherein in step (1), the liquid butene-1-containing monomer further comprises an α -olefin comonomer;

preferably, the alpha-olefin comonomer comprises a C2-C10 alpha-olefin; more preferably, the alpha-olefin comonomer may comprise ethylene and/or propylene.

3. The method for continuous industrial production of highly isotactic polybutene-1 of claim 1, wherein in step (1), the catalyst system comprises a main catalyst, a cocatalyst and an external electron donor compound;

preferably, the main catalyst comprises a titanium-based solid catalyst; more preferably, the main catalyst comprises a magnesium halide supported titanium-based solid catalyst and/or a magnesium alkoxide supported titanium-based solid catalyst; further preferably, the main catalyst is used in an amount of: 30000-140000g of liquid butene-1/g of main catalyst;

preferably, the cocatalyst comprises an alkyl aluminium compound; more preferably, the cocatalyst comprises one or a combination of several of triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum and tri-n-octylaluminum; further preferably, the cocatalysts are used in an amount of: 850-14000g liquid butene-1/g cocatalyst;

preferably, the external electron donor compound comprises an alkoxysilane compound; more preferably, the external electron donor compound includes one or a combination of several of dicyclopentyl dimethoxy silane, cyclohexylmethyl dimethoxy silane, dicyclohexyl dimethoxy silane, cyclohexyltriethoxy silane, methyltriethoxy silane, methylcyclopentyldimethoxy silane, isobutyiisopropyl dimethoxy silane, isopropylcyclopentyl dimethoxy silane and isobutyitriethoxy silane; further preferably, the external electron donor compound is used in an amount of: 40000-250000g of liquid butene-1/g of external electron donor compound.

4. The method for continuous industrial production of highly isotactic polybutene-1 according to claim 1, wherein in the step (1), the polymerization reaction is carried out in the presence of hydrogen and inert gas;

preferably, the hydrogen is used in an amount of: 1500-300000g of liquid butene-1/g of hydrogen;

preferably, the inert gas comprises nitrogen.

5. The method for continuous industrial production of highly isotactic polybutene-1 according to claim 1, wherein in the step (1), the polymerization reaction temperature is 50-80 ℃, the reaction pressure is 2.0-2.5MPa, and the reaction time is 2-5 hours; preferably, the temperature of the polymerization reaction is 65-75 ℃, the reaction pressure is 2.0-2.2MPa, and the reaction time is 3-4 hours;

preferably, in step (1), the polymer solution has a polymer weight concentration of 20 to 25%.

6. The method for continuous industrial production of highly isotactic polybutene-1 of claim 1, wherein in step (2), the first pressure is 2.8-3.2MPa and the first temperature is 195-205 ℃;

preferably, step (2) comprises: boosting the polymer solution flowing out of the deactivation pot to the first pressure by using a pump, and then raising the temperature of the boosted polymer solution to the first temperature by using a heat exchanger;

Preferably, in the step (2), the second temperature is 205-215 ℃, and the second pressure is 0.001-0.003MPa;

more preferably, step (2) comprises: heating the polybutene-1 melt subjected to the first demonomerization to the second temperature by adopting a heat exchanger, then entering a second demonomerization tower, and controlling the operating pressure of the second demonomerization tower at the second pressure by adopting a vacuum pump arranged outside the tower top of the second demonomerization tower;

preferably, in the step (2), a plurality of layers of conical surfaces are arranged in the vertical direction in the tower bodies of the first monomer removing tower and the second monomer removing tower, and each layer of conical surface comprises a downward opening dispersion surface and an upward opening receiving surface which are adjacently arranged in the vertical direction; the tower top is provided with a feed inlet and a gas outlet; a discharge hole is arranged at the bottom of the tower; more preferably, the cone angle of the conical surfaces of the layers is 130-150 degrees; more preferably, the number of conical surfaces inside the tower body is an odd number of 5-9, and the first layer of conical surfaces in the vertical direction are dispersion surfaces with downward openings; further preferably, the number of conical surfaces inside the tower body is seven, and the first conical surface in the vertical direction is a dispersion surface with downward openings;

Preferably, in step (2), the monomer content in the polybutene-1 melt after the second demonomerization is below 35 ppm.

7. The method for continuous industrial production of highly isotactic polybutene-1 according to claim 1, wherein in the step (3), the monomer recovery unit comprises at least a separation column; the step (3) comprises: separating monomer-containing gas flowing out of the first and second monomer removal towers at least through a separation tower, and separating out monomer gas and a terminator;

preferably, the monomer recovery unit further comprises a buffer tank; step (3) further comprises: the monomer-containing gas flowing out of the first monomer removal tower and the second monomer removal tower firstly pass through a buffer tank respectively and then enter a separation tower for separation;

preferably, the monomer recovery unit further comprises one or a combination of several of a condenser, a scrubber and a drying column; step (3) further comprises: the monomer gas separated by the separation tower is treated by one or a combination of condensation, washing and drying to obtain a treated monomer;

preferably, the monomer recovery unit further comprises a monomer storage tank; step (3) further comprises: enabling the treated monomer to enter the monomer storage tank for storage;

Preferably, step (3) further comprises: enabling the treated monomer or the monomer stored in the monomer storage tank to enter a polymerization kettle in the step (1) for recycling;

preferably, step (3) further comprises: and (3) enabling the terminator separated by the separation tower to enter a deactivation pot in the step (2) for recycling.

8. The method for continuous industrial production of highly isotactic polybutene-1 according to claim 1, wherein in the step (4), the extrusion is carried out using a screw extruder;

preferably, the screw extruder has a vacuum degasser;

preferably, step (4) further comprises: in the process that the polybutene-1 melt after the second monomer removal is extruded by a screw extruder, the residual monomer is further removed by a vacuum degassing device of the screw extruder;

preferably, step (4) further comprises: adding an additive in the process of extruding the polybutene-1 melt subjected to the second monomer removal by a screw extruder to obtain a mixture of polybutene-1 and the additive, and granulating;

preferably, in step (4), the granulation is carried out using an underwater granulator.

9. An apparatus for continuous industrial production of highly isotactic polybutene-1 for realizing the method of continuous industrial production of highly isotactic polybutene-1 according to any one of claims 1 to 8, comprising: a polymerization unit, a polymer separation unit, a monomer recovery unit, and a polymer granulation unit;

the polymer granulating unit comprises an extruder and a granulator;

10. The apparatus for continuous industrial production of highly isotactic polybutene-1 of claim 9, wherein the reaction system inlet of the polymerization vessel comprises: a monomer inlet, a catalyst system inlet, a hydrogen inlet, and an inert gas inlet; preferably, the monomer inlet comprises a liquid butene-1 inlet and optionally an alpha-olefin comonomer inlet;

preferably, a plurality of layers of conical surfaces are arranged in the tower bodies of the first monomer removing tower and the second monomer removing tower in the vertical direction, and each layer of conical surface comprises a downward opening dispersing surface and an upward opening receiving surface which are adjacently arranged in the vertical direction; the tower top is provided with the feed inlet and the gas outlet; the bottom of the tower is provided with the discharge hole; more preferably, the cone angle of the conical surfaces of the layers is 130-150 degrees; more preferably, the number of conical surfaces inside the tower body is an odd number of 5-9, and the first layer of conical surfaces in the vertical direction are dispersion surfaces with downward openings; further preferably, the number of conical surfaces inside the tower body is seven, and the first conical surface in the vertical direction is a dispersion surface with downward openings;

Preferably, the booster pump comprises a gear pump or screw pump, more preferably a gear pump;

preferably, the first heat exchanger and the second heat exchanger each comprise a multi-tube heat exchanger;

preferably, a delivery pump is arranged at the discharge port of the first monomer removal tower and used for discharging the tower bottom material from the discharge port and delivering the tower bottom material to the second heat exchanger; more preferably, the transfer pump comprises a gear pump or a screw pump, even more preferably a gear pump;

preferably, a delivery pump is arranged at the discharge port of the second monomer removal tower and is used for discharging the tower bottom material from the discharge port and delivering the tower bottom material to the extruder; more preferably, the transfer pump comprises a gear pump or a screw pump, even more preferably a gear pump;

preferably, the monomer recovery unit comprises at least a separation column provided with a material inlet, a monomer gas outlet and a terminator outlet; the gas outlet of the first demonomerization tower is connected with the material inlet of the separation tower through a pipeline, and the gas outlet of the second demonomerization tower is connected with the material inlet of the separation tower through a pipeline and the vacuum pump; the separation tower is used for separating the monomer-containing gas flowing out of the first monomer removal tower and the second monomer removal tower at least, and then separating the monomer gas and the terminator;

Preferably, the monomer recovery unit further comprises buffer tanks, wherein the buffer tanks are respectively arranged on a pipeline connected with the gas outlet of the first monomer removal tower and the separation tower, and a pipeline connected with the outlet of the vacuum pump outside the second monomer removal tower and the separation tower; the gas containing the monomer, which flows out of the first monomer removing tower and the second monomer removing tower, firstly passes through the buffer tank and then enters the separation tower for separation;

preferably, the monomer recovery unit further comprises one or a combination of several of a condenser, a scrubber and a drying column; one or more combinations of a condenser, a scrubber and a drying tower are arranged at the rear part of the separation tower and are used for processing the monomer gas separated by the separation tower through one or more combinations of condensation, washing and drying to obtain a processed monomer;

preferably, the monomer recovery unit further comprises a monomer storage tank disposed at the rear of one or a combination of several of the condenser, scrubber and drying tower for storing the treated monomer; more preferably, the monomer storage tank is a liquid butene-1 storage tank;

Preferably, the monomer recovery unit further comprises a monomer circulation line, one end of the monomer circulation line is communicated with the reaction system inlet of the polymerization kettle, and the other end of the monomer circulation line is connected to the outlet of the scrubber, the outlet of the condenser, the outlet of the drying tower or the outlet of the monomer storage tank; the method is used for recycling the monomers;

preferably, the monomer recovery unit further comprises a terminator circulation line, one end of which is connected to a terminator inlet of the deactivation tank, and the other end of which is connected to a terminator outlet of the separation column, for recycling the terminator separated by the separation column;

preferably, the extruder comprises a screw extruder; more preferably, the screw extruder has a vacuum degasser;

preferably, the pelletizer includes an underwater pelletizer.