Method and system for continuously producing polyolefin elastomer by gas phase method

Abstract

The invention provides a method and system for continuously producing a polyolefin elastomer by a gas phase method, and the method comprises the following steps: mixing ethylene, alpha-olefin, hydrogen, nitrogen, a condensing agent and nitrogen to obtain a mixed material; carrying out polymerization reaction on the mixed material, a catalyst and an antistatic agent to obtain polyolefin elastomer powder, a polymerization reaction block material and an unreacted material; carrying out separation, first-stage heat exchange, pressurization and second-stage heat exchange treatment on the unreacted material in sequence, and then adding the unreacted material into the mixed material; wherein the polymerization reaction block material is treated as a waste material, and the polyolefin elastomer powder is used as a product. By adopting the preparation method of the polyolefin elastomer, heat removal can be accelerated, so that softening, caking and blocking of a polymer are effectively prevented, the fine powder content of the polymer is reduced, and by adopting the system, the problems of safety and stability in a gas-phase polymerization production process can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of polyolefin elastomers, and in particular to a method and system for continuously producing polyolefin elastomers by a gas phase process. Background Art

[0002] Polyolefin elastomer (POE) has a high content of comonomers in its molecular chain and low density. The polymer consists of a crystalline resin phase and an amorphous rubber phase. The material has both the high elasticity of rubber and the plasticity of thermoplastic resin, and is easy to process and shape. Polyolefin elastomer is a key raw material in the fields of photovoltaic films, new energy vehicles, wires and cables, and is a high-end polyolefin product.

[0003] Before 2023, the production capacity and complete production technology of polyolefin elastomers were mainly controlled by overseas companies such as Dow, Exxon, Mitsui, SK-SABIC, LG, and Borealis, all of which were solution polymerization processes. In recent years, related companies have increased their efforts in the development of polyolefin elastomers, developed solution polymerization processes and gas phase polymerization processes, and have achieved zero breakthroughs in polyolefin elastomer industrial products. Compared with the solution polymerization process, the gas phase polymerization process has the characteristics of short operation process, low production cost, and low product odor. Its process and product characteristics are distinct and have high scientific and technological development value.

[0004] In the process of preparing polyolefins by gas phase polymerization process, due to the low melting point and softening point of polyolefin elastomer, the polymer is easy to soften and clog in the reactor, resulting in belt-like blocks; the polymer fine powder produced by the polymerization reaction is easy to soften and scale in the pipeline, and the above phenomena will make it difficult to maintain the fluidized state in the gas phase fluidized bed reactor, and it is impossible to achieve homogeneous reaction. In addition, a large amount of static electricity is easily generated in the polymerization reaction system, and static electricity causes the polymer to stick to the reactor wall and cause the temperature monitoring in the reactor to be distorted; the polymer fine powder blocks the pressure sensor pipeline, resulting in abnormal monitoring of the reactor bed pressure difference, and the above phenomena will cause the gas phase fluidized bed reactor to be unable to operate normally, and the polymerization reaction is forced to stop, affecting the continuous production of the device. In order to solve the above problems, the Chinese invention patent publication number is: CN113382999A discloses the continuous feeding of an antistatic agent for a gas phase polymerization process, and the method may include reacting the antistatic agent with at least one alkyl aluminum to form an antistatic compound, and may also include feeding the antistatic compound into the polymerization process. The method of using an antistatic agent in a polymerization process may include feeding the antistatic agent into the polymerization process and then reacting the antistatic agent with at least one alkyl aluminum. The Chinese invention patent publication number is: CN108948248B discloses a method, device and application of a polyolefin elastomer produced by a gas phase method, wherein the method is to react in a reactor with polyethylene particles as a seed bed, pass a raw material mixed gas including ethylene, hydrogen and nitrogen into the reactor, so that the polyethylene particles in the seed bed flow and reach a fluidized state, and then add a catalyst into the reactor and pass atomized droplet-shaped comonomer to react. The patent must atomize the comonomer, and requires a test device that has undergone structural modification. The polymerization temperature used is generally higher than the melting point of the product, and there is a risk of polymer stickiness blocking the reactor and pipelines. A series of problems such as blockage and agglomeration that may occur in the system after polymerization are not considered.

[0005] Based on this, the above-mentioned related patents in the prior art mainly involve the use of different types of antistatic agents and their use methods, or a method for producing polyolefin elastomers by using a gas-phase fluidized bed reactor based on a special structural form, which solves the problem of uneven distribution of liquid long-chain α-olefins with high comonomer content in the gas-phase seed bed and poor copolymerization performance in the preparation process of polyolefin elastomers, but cannot solve the technical problem that in the process of producing polyolefin elastomers in the gas-phase fluidized bed reactor, there are material agglomeration and skinning phenomena, which make the fluidization state poor and cause the gas-phase fluidized bed reactor to be unable to operate normally. Therefore, it is urgent to provide a new method and system for preparing polyolefin elastomers to improve the above-mentioned problems. Summary of the invention

[0006] The main purpose of the present invention is to provide a method and system for continuously producing polyolefin elastomers by a gas phase method, so as to solve the technical problem in the prior art that the fluidization state of the gas phase fluidized bed reactor in the process of producing polyolefin elastomers is poor, resulting in the gas phase fluidized bed reactor being unable to operate normally.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for continuously producing polyolefin elastomers by gas phase process is provided, which method comprises the following steps: ethylene, α-olefin, hydrogen, nitrogen, condensing agent and nitrogen are mixed to obtain a mixed material; the mixed material, a catalyst and an antistatic agent are polymerized to obtain polyolefin elastomer powder, polymerization reaction blocks and unreacted materials; the unreacted materials are sequentially separated, subjected to primary heat exchange, pressurized and subjected to secondary heat exchange treatment, and then added to the mixed material; wherein the polymerization reaction blocks are treated as waste and the polyolefin elastomer powder is taken as a product.

[0008] Furthermore, the separation includes primary separation and secondary separation to remove polyolefin elastomer powder entrained in the unreacted materials, the entrained polyolefin elastomer powder enters the reactor as polyolefin elastomer powder, and the pressurization treatment is carried out in the compressor; the primary separation is firstly carried out to separate the unreacted materials, and then the secondary separation is carried out to separate the unreacted materials after the primary separation, so as to separate the entrained polyolefin elastomer powder and the unreacted gas phase reaction materials, wherein the separated entrained polyolefin elastomer powder is used as the product.

[0009] Furthermore, the α-olefin is 1-butene and / or 1-hexene; the condensing agent is selected from one or more of propane, pentane, cyclopentane, hexane and cyclohexane; preferably, in the mixed material, the α-olefin accounts for 20-30% of the sum of the mass of the α-olefin and ethylene, and the condensing agent accounts for 1.0-8.0% of the mass of the mixed material.

[0010] Furthermore, the polymerization reaction pressure is 1.5-3.0 MPa, the reaction temperature is 35-70°C, and the reaction time is 8-18 hours; the catalyst is a metallocene catalyst, and the active components of the catalyst contain one or more of zirconocene chloride, methylaluminoxane, butylaluminoxane and hexylaluminoxane, and the yield of the catalyst is 5000-11000 g product / g catalyst.

[0011] Furthermore, the antistatic agent includes alkylbenzene sulfonic acid, 1-decene homopolymer and organic solvent. The weight percentage of each component in the antistatic agent is: 4-10% of alkylbenzene sulfonic acid, 10-15% of 1-decene homopolymer, and 77-85% of organic solvent. The organic solvent is C6-C8 alkane and / or cycloalkane. The added amount of the antistatic agent accounts for 0.0025-0.0085% of ethylene.

[0012] Furthermore, the density of the polyolefin elastomer powder is 0.872~0.890g / cm 3 , the melt mass flow rate is 0.5~15g / 10min, the content of particles with a particle size of 100~1000μm is 7.5~18.6%, and the content of particles with a particle size of 1600~4500μm is 27.1~48.5%.

[0013] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a system for continuously producing polyolefin elastomers by a gas phase method is provided, the system comprising: a primary heat exchange unit, a secondary heat exchange unit, a pressurizing unit, a gas-phase fluidized bed reaction unit, a separation unit, a material input unit and a material output unit; wherein, the inlet of the material output unit is connected to the outlet of the separation unit, the outlet of the material output unit is connected to the inlet of the primary heat exchange unit, the outlet of the primary heat exchange unit is connected to the inlet of the pressurizing unit, the outlet of the pressurizing unit is connected to the inlet of the secondary heat exchange unit, the outlet of the secondary heat exchange unit is connected to the inlet of the material input unit, the outlet of the material input unit is connected to the bottom inlet of the gas-phase fluidized bed reaction unit, the outlet of the gas-phase fluidized bed reaction unit is connected to the inlet of the separation unit, and the outlet of the separation unit is respectively connected to the side inlet of the gas-phase fluidized reaction unit and the inlet of the material output unit.

[0014] Furthermore, the gas-phase fluidized bed reaction unit is a gas-phase fluidized bed reactor, and a catalyst injection port and an antistatic agent injection port are arranged at the fluidizing end of the gas-phase fluidized bed reactor. The antistatic agent injection port is located directly below the catalyst injection port, and the injection direction of the catalyst is perpendicular to the direction of the gas-phase fluidized bed reactor. The injection direction of the antistatic agent into the antistatic agent injection port and the injection direction of the catalyst into the catalyst injection port are at an angle of 30 to 60 degrees.

[0015] Furthermore, temperature monitors, pressure monitors and electrostatic monitors are independently arranged in the axial and radial directions of the gas fluidized bed reactor; the lower gas phase fluidization rate of the gas fluidized bed reactor is 0.40~0.80m / s; the separation unit includes a primary separation unit and a secondary separation unit, the separation unit is a separator, and the primary heat exchange unit and the secondary heat exchange unit are both heat exchangers.

[0016] Furthermore, in the gas-phase fluidized bed reactor, the pressure of the nitrogen backwash of the bed pressure difference monitoring instrument is 2.5~3.5MPa, the electrostatic monitoring value in the gas-phase fluidized bed reactor is ±1000~±4000PA, and the discharge amount of the polymerization reaction block material in the bottom hopper of the gas-phase fluidized bed reactor is 0.5~5kg / 8h.

[0017] The present invention has the following beneficial effects: the method for continuously producing polyolefin elastomers by the gas phase method disclosed in the present invention, after the unreacted materials are separated, subjected to primary heat exchange, pressurized and subjected to secondary heat exchange treatment in sequence, they are added to the mixed materials, and the polymerization reaction blocks are treated as waste. The specific separation includes: firstly performing a primary separation to separate the unreacted materials, and then performing a secondary separation to separate the unreacted materials after the primary separation, separating the entrained polyolefin elastomer powder and the unreacted gas phase reaction materials, wherein the separated entrained polyolefin elastomer powder is used as the product, and the unreacted gas phase reaction materials are further reacted. On the one hand, it can effectively prevent the fine powder in the polymer powder from entering the heat exchanger, the compressor and each connecting pipe to soften and clog. On the other hand, it can also achieve continuous operation, save process time, and improve production efficiency.

[0018] Specifically, the method for continuously producing polyolefin elastomers in the present invention can further increase the rapid removal of heat generated by the polymerization reaction in the reactor, effectively preventing the polymer in the reactor from softening, agglomerating and clogging; the antistatic effect can be enhanced by changing the injection position and method of the antistatic agent, effectively preventing the polymer from sticking to the reactor wall and forming a skin, which causes production fluctuations; by using a metallocene catalyst and controlling the gas phase fluidization rate, the content of polymer fine powder is reduced, thereby preventing the polymer fine powder from softening, scaling and clogging in the pipeline.

[0019] In summary, the system of the present invention is used to implement the above-mentioned method for producing polyolefin elastomers, which can solve the safety and stability problems existing in the production of polyolefin elastomers by gas phase polymerization process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application. In the drawings: Figure 1 A flow chart of a method for continuously producing a polyolefin elastomer by a gas phase method according to one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] According to the background technology part of the present invention, in the process of producing polyolefin elastomers in the gas-phase fluidized bed reactor in the prior art, there is a poor fluidization state, which makes the gas-phase fluidized bed reactor unable to operate normally. Based on this, the present invention provides a method for continuously producing polyolefin elastomers by gas phase method, which includes the following steps: mixing ethylene, α-olefin, hydrogen, condensing agent and nitrogen to obtain a mixed material; polymerizing the mixed material, catalyst and antistatic agent to obtain polyolefin elastomer powder, polymerization block and unreacted material; separating the unreacted material, performing primary heat exchange, pressurizing and secondary heat exchange treatment in sequence, and adding it to the mixed material; wherein the polymerization block is treated as waste and the polyolefin elastomer powder is used as a product.

[0023] The present invention adopts a gas phase method to prepare polyolefin elastomers. First, ethylene, α-olefin, hydrogen, condensing agent and nitrogen are mixed to obtain a mixed material; then the mixed material, catalyst and antistatic agent are polymerized to obtain polyolefin elastomer powder, polymerization block and unreacted material; finally, the unreacted material is separated, subjected to primary heat exchange, pressurized and secondary heat exchange treatments in sequence, and then added to the mixed material; wherein the polymerization block is treated as waste and the polyolefin elastomer powder is used as a product. In the production process, the unreacted material is separated to remove the polymer fine powder entrained therein, and the entrained fine powder is prevented from softening, scaling and clogging the pipeline, and the density is prevented from increasing due to the entrainment of fine powder, thereby causing the power of the pressurized unit to increase; then the reaction is carried out after two-stage heat exchange, and the unreacted material is pressurized to increase the pressure, and after entering the bottom of the reactor, it is mixed with the reaction raw materials as raw materials for subsequent treatment, and the polymer powder entering the reactor is further fluidized, thereby realizing the continuous production of polyolefin elastomers by the gas phase method.

[0024] In a preferred embodiment, the separation includes primary separation and secondary separation, and the separation is to remove the polyolefin elastomer powder entrained in the unreacted material. More preferably, the pressure treatment is carried out in a compressor.

[0025] In order to further prepare a polyolefin elastomer product with excellent performance, the α-olefin is 1-butene and / or 1-hexene; the condensing agent is selected from one or more of propane, pentane, cyclopentane, hexane, and cyclohexane; more preferably, in the mixed material, the α-olefin accounts for 20-30% of the total mass of the α-olefin and ethylene, and the condensing agent accounts for 1.0-8.0% of the mass of the mixed material.

[0026] In a preferred embodiment, the polymerization reaction pressure is 1.5-3.0 MPa, the reaction temperature is 35-70°C, and the reaction time is 8-18 hours; more preferably, the catalyst is a metallocene catalyst, the active component of the catalyst contains one or more of zirconocene chloride, methylaluminoxane, butylaluminoxane or hexylaluminoxane, and the catalyst yield is 5000-11000 g product / g catalyst. A large-particle-size, high-activity metallocene catalyst is used so that the polymerization reaction generates large-particle-size polyolefin elastomer powder, thereby reducing the generation of fine powder.

[0027] In order to further prevent the formation of skin on the inner wall of the gas phase fluidized bed reactor, thereby affecting the accurate monitoring of the pressure and temperature in the reactor, the antistatic agent preferably includes alkylbenzene sulfonic acid, 1-decene homopolymer and organic solvent. The weight percentage of each component in the antistatic agent is: 4-10% alkylbenzene sulfonic acid, 10-15% 1-decene homopolymer, 77-85% organic solvent, the organic solvent is C6-C8 alkane and / or cycloalkane, and the added amount of the antistatic agent accounts for 0.0025-0.0085% of ethylene.

[0028] In a preferred embodiment, the density of the polyolefin elastomer powder is 0.872-0.885 g / cm 3 , the melt mass flow rate is 0.5~15g / 10min, the content of particles with a particle size of 100~1000μm is 7.5~18.6%, and the content of particles with a particle size of 1600~4500μm is 27.1~48.5%.

[0029] On the other hand, the present invention also provides a system for continuously producing polyolefin elastomers by a gas phase method, the system comprising: a primary heat exchange unit, a secondary heat exchange unit, a pressurizing unit, a gas-phase fluidized bed reaction unit, a separation unit, a material input unit and a material output unit; wherein, the inlet of the material output unit is connected to the outlet of the separation unit, the outlet of the material output unit is connected to the inlet of the primary heat exchange unit, the outlet of the primary heat exchange unit is connected to the inlet of the pressurizing unit, the outlet of the pressurizing unit is connected to the inlet of the secondary heat exchange unit, the outlet of the secondary heat exchange unit is connected to the inlet of the material input unit, the outlet of the material input unit is connected to the bottom inlet of the gas-phase fluidized bed reaction unit, the outlet of the gas-phase fluidized bed reaction unit is connected to the inlet of the separation unit, and the outlet of the separation unit is respectively connected to the side inlet of the gas-phase fluidized reaction unit and the inlet of the material output unit.

[0030] In a preferred embodiment, the gas-phase fluidized bed reaction unit is a gas-phase fluidized bed reactor, and a catalyst injection port and an antistatic agent injection port are arranged at the fluidizing end of the gas-phase fluidized bed reactor. The antistatic agent injection port is located directly below the catalyst injection port, and the injection direction of the catalyst is perpendicular to the direction of the gas-phase fluidized bed reactor. The injection direction of the antistatic agent into the antistatic agent injection port is at an angle of 30 to 60 degrees to the injection direction of the catalyst into the catalyst injection port, thereby effectively preventing the polymer from sticking to the reactor wall and causing production fluctuations.

[0031] As the present invention Figure 1 As shown, after the raw materials ethylene, α-olefin, condensing agent, hydrogen and nitrogen are mixed, the mixed material is passed through the material conveying unit into the gas phase fluidized bed reaction unit, i.e., the gas phase fluidized bed reactor. Then, the antistatic agent and the catalyst are added to the antistatic agent injection port and the catalyst injection port in the gas phase fluidized bed reactor, respectively, and a polymerization reaction is carried out in the gas phase fluidized bed reactor to obtain polyolefin elastomer powder, polymerization reaction block material and unreacted material. Among them, the polyolefin elastomer powder is discharged from the lower end of the gas phase fluidized bed reactor through the powder extraction line as a product, and the powder extraction line is arranged at the lower end of the gas phase fluidized bed reactor; the polymerization reaction block material is discharged from the hopper at the bottom end of the gas phase fluidized bed reactor; the unreacted material (including the unreacted gas phase reaction raw material and the entrained polyolefin elastomer product powder) is discharged through the top of the gas phase fluidized bed reactor, and enters the primary separation unit and the secondary separation unit in sequence. The unreacted gas phase reaction material and the entrained polyolefin elastomer product powder obtained by the above secondary separation, wherein the entrained polyolefin elastomer The product powder enters the gas-phase fluidized bed reactor through the side inlet of the gas-phase fluidized bed reactor as a polyolefin elastomer powder product; the unreacted gas-phase reaction materials enter the primary heat exchange unit through the material output unit for primary heat exchange treatment, are supplemented with hydrogen and nitrogen, enter the pressurizing unit again for pressurization treatment, enter the secondary heat exchange unit for secondary heat exchange treatment, and enter the gas-phase fluidized bed reactor again with ethylene, α-olefin and condensing agent through the material conveying unit for polymerization reaction. CWR represents the return water of circulating cooling water (medium with low temperature); CWS represents the upper water of circulating cooling water.

[0032] In order to further monitor the temperature, pressure and static electricity in the gas fluidized bed reactor, it is preferred that a temperature monitor, a pressure monitor and a static electricity monitor are independently arranged in the axial and radial directions of the gas fluidized bed reactor; the lower gas phase fluidization rate of the gas fluidized bed reactor is 0.40~0.8m / s; the separation unit includes a primary separation unit and a secondary separation unit, the separation unit is a separator, and the primary heat exchange unit and the secondary heat exchange unit are both heat exchangers.

[0033] In a preferred embodiment, in the gas-phase fluidized bed reactor, the pressure of the nitrogen backflushing of the bed pressure difference monitoring instrument is 3.0~3.5MPa, the purpose of the nitrogen backflushing is to prevent the instrument pipeline from being blocked by fine powder, the electrostatic monitoring value in the gas-phase fluidized bed reactor is ±1000~±4000PA, and the discharge amount of the polymerization reaction block material in the bottom hopper of the gas-phase fluidized bed reactor is 0.5~5kg / 8h.

[0034] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0035] Example 1 The α-olefin is 1-butene, the condensing agent is pentane, and the mixed material is composed of ethylene, 1-butene, hydrogen, nitrogen, and pentane. 1-butene accounts for 20.2% of the total mass of 1-butene and ethylene, and the mass proportion of pentane in the mixed material is 7.8%. Under the operating conditions of polymerization pressure of 1.55MPa and temperature of 65℃, the catalyst yield is 10700g product / g catalyst, and the mass percentage of antistatic agent addition to ethylene is 0.0025%; the gas phase fluidization rate at the bottom of the reactor is 0.78m / s, and the pressure of nitrogen backwash of the reactor bed pressure difference monitoring instrument is 2.5MPa; the polymerization reactor operates stably, and the average reaction time is 8.5h. The injection direction of the antistatic agent into the antistatic agent injection port is at an angle of 30 degrees to the injection direction of the catalyst into the catalyst injection port. The antistatic agent includes alkylbenzene sulfonic acid, 1-decene homopolymer and organic solvent, and the specific content of each component is 4% alkylbenzene sulfonic acid, 12% 1-decene homopolymer and 84% cyclohexane solvent. The catalyst is a metallocene catalyst, and the active components are zirconocene chloride and methylaluminoxane.

[0036] The polyolefin elastomer powder is produced by the above method. During the production process, the electrostatic monitoring value in the reactor is -2000~1000PA, and there is no polymer sticking and skinning phenomenon on the reactor wall; the block discharge rate of the hopper at the bottom of the reactor is 1.6kg / 8h, and there is no polymer softening, agglomeration and blockage phenomenon in the reactor; the obtained polyolefin elastomer powder has a particle size of 100~1000μm and a particle size of 1600~4500μm. The content of particles is 7.5%, and the content of particles is 48.0%, and the content of fine powder is relatively low. The obtained polyolefin elastomer powder has a density of 0.8880g / cm 3 , melt mass flow rate 5.1g / 10min.

[0037] Example 2 The only difference from Example 1 is that the condensing agent is cyclopentane, 1-butene accounts for 23.1% of the total mass of 1-butene and ethylene, the mass proportion of cyclopentane in the mixed material is 6.3%, and the catalyst yield is 9500g product / g catalyst under the operating conditions of polymerization pressure 2.15MPa and temperature 58°C; the mass percentage of antistatic agent addition to ethylene is 0.0045%, and the average reaction time is 10h.

[0038] The polyolefin elastomer powder is produced by the above method. During the production process, the electrostatic monitoring value in the reactor is -1200~1000PA, and there is no polymer sticking and skinning phenomenon on the reactor wall; the block discharge rate of the hopper at the bottom of the reactor is 0.65kg / 8h, and there is no polymer softening, agglomeration and blockage phenomenon in the reactor; the obtained polyolefin elastomer powder has a particle size of 100~1000μm and a particle size of 1600~4500μm. The content of particles is 9.9%, and the content of particles is 43.2%, and the content of fine powder is relatively low. The obtained polyolefin elastomer powder has a density of 0.8790g / cm 3 , melt mass flow rate: 0.98g / 10min.

[0039] Example 3 The only difference from Example 1 is that the condensing agent is propane, 1-butene accounts for 28.2% of the mass of 1-butene and ethylene, the mass proportion of propane in the mixed material is 4.3%, the catalyst yield is 5300g product / g catalyst under the working conditions of polymerization pressure 3.0MPa and temperature 38°C, the mass percentage of antistatic agent addition and ethylene is 0.0080%; the gas phase fluidization rate at the bottom of the reactor is 0.42m / s, the pressure of the back-blowing nitrogen of the reactor bed pressure difference monitoring instrument is 3.5MPa, and the average reaction time is 17.5h. The injection direction of the antistatic agent into the antistatic agent injection port is 60 degrees from the injection direction of the catalyst into the catalyst injection port. The component content of the antistatic agent is 7.5% alkylbenzene sulfonic acid, 14.5% 1-decene homopolymer, and 78% n-heptane solvent. The catalyst is a metallocene catalyst, and the active components are zirconocene chloride and butylaluminoxane.

[0040] The polyolefin elastomer powder is produced by the above method. During the production process, the electrostatic monitoring value in the reactor is -2600~1000PA, and there is no polymer sticking and skinning phenomenon on the reactor wall; the block discharge rate of the hopper at the bottom of the reactor is 4.3kg / 8h, and there is no polymer softening, agglomeration and blockage phenomenon in the reactor; the obtained polyolefin elastomer powder has a particle size of 100~1000μm and a particle size of 1600~4500μm. The content of particles is 7.7%, and the content of particles is 44.5%, and the content of fine powder in the polymer is low. The obtained polyolefin elastomer powder has a density of 0.8722g / cm 3, melt mass flow rate: 14g / 10min.

[0041] Example 4 The only difference from Example 1 is that the α-olefin is 1-hexene, the condensing agent is propane, 1-hexene accounts for 23.5% of the mass of 1-hexene and ethylene, the mass proportion of propane in the mixed material is 2.8%, and the catalyst yield is 7500g product / g catalyst under the working conditions of polymerization pressure 3.0MPa and temperature 52°C; the mass percentage of antistatic agent addition to ethylene is 0.0060%, and the average reaction time is 13h. The component content of the antistatic agent is 10.0% alkylbenzene sulfonic acid, 10.0% 1-decene homopolymer, and 80% n-decane solvent. The catalyst is a metallocene catalyst, and the active components are dichlorozirconium and hexylaluminoxane.

[0042] The polyolefin elastomer powder is produced by the above method. During the production process, the electrostatic monitoring value in the reactor is -3000~1500PA, and there is no polymer sticking and skinning phenomenon on the reactor wall; the block discharge rate of the hopper at the bottom of the reactor is 3.0kg / 8h, and there is no polymer softening, agglomeration and clogging phenomenon in the reactor; the obtained polyolefin elastomer powder has a particle size of 100~1000μm and a particle size of 1600~4500μm. The content of particles is 14.3%, and the content of particles is 28.9%, and the content of fine powder in the polymer is low. The obtained polyolefin elastomer powder has a density of 0.8840g / cm 3 , melt mass flow rate: 1.0g / 10min.

[0043] Example 5 The only difference from Example 4 is that the α-olefin is 1-hexene and 1-butene, the α-olefin accounts for 24.8% of the total mass of α-olefin and ethylene, the mass proportion of propane in the mixed material is 1.2%, the catalyst yield is 6300g product / g catalyst, the mass percentage of the antistatic agent addition amount to ethylene is 0.0080%; the gas phase fluidization rate in the lower part of the reactor is 0.52m / s, and the average reaction time is 9h.

[0044] The polyolefin elastomer powder is produced by the above method. During the production process, the electrostatic monitoring value in the reactor is -3000~1500PA, and there is no polymer sticking and skinning phenomenon on the reactor wall; the block material discharge rate of the hopper at the bottom of the reactor is 1.2kg / 8h, and there is no polymer softening, agglomeration and blockage phenomenon in the reactor; the obtained polyolefin elastomer powder has a particle size of 100~1000μm and a particle size of 1600~4500μm. The content of particles is 12.2%, and the content of particles is 30.0%, and the content of fine powder in the polymer is low. The obtained polyolefin elastomer powder has a density of 0.8800g / cm 3, melt mass flow rate 4.94g / 10min.

[0045] Comparative Example 1 The only difference from Example 1 is that the condensing agent is propane, the catalyst yield is 14500g product / g catalyst under the operating conditions of polymerization pressure 1.05MPa and temperature 75°C, the mass percentage of antistatic agent addition amount to ethylene is 0.0019%; the gas phase fluidization rate in the lower part of the reactor is 0.90m / s, and the pressure of nitrogen backwash of the reactor bed pressure difference monitoring instrument is 0.5MPa; the polymerization reactor operates unstably, and the average reaction time is 5.0h.

[0046] The polyolefin elastomer powder was produced by the above method. During the production process, the maximum static monitoring value in the reactor was -7300PA, the static charge in the reaction system was high, the temperature monitoring of the reactor wall gave an alarm, and it was suspected that the reactor wall had a polymer skinning phenomenon; the block discharge rate of the hopper at the bottom of the reactor was 63kg / 8h, and there was a belt-shaped block block; the obtained polyolefin elastomer powder had a particle size of 100~1000μm and a particle size of 1600~4500μm. The content of particles was 28.7%, and the content of particles was 17.6%, and the content of fine powder was high. To ensure safe production, the gas phase fluidized bed polymerization reaction was stopped.

[0047] Comparative Example 2 The only difference from Example 3 is that the condensing agent is cyclohexane, the mass proportion of cyclohexane in the mixed material is 3.0%, the catalyst yield is 2000g product / g catalyst under the operating conditions of polymerization pressure 1.55MPa and temperature 33°C, the gas phase fluidization rate in the lower part of the reactor is 0.35m / s, the average reaction time is 42h, the catalyst yield is low, and the energy consumption of the device for continuous production of polyolefin elastomers is high.

[0048] The polyolefin elastomer was produced by the above method. During the production process, the maximum static monitoring value in the reactor was -5200PA, the static charge in the reaction system was high, the pressure difference of the distribution plate in the gas phase reactor continued to rise within 2 days of continuous operation of the device, and the discharge of bulk material from the hopper at the bottom of the reactor gradually increased to 45kg / 8h. It was suspected that the material softened, agglomerated and blocked in the reactor; the obtained polyolefin elastomer powder had a particle size of 100~1000μm and a particle size of 1600~4500μm, respectively. The content was 14.5%, and the content of particles was 15.0%, and the particle size was generally small. In order to ensure safe production, the gas phase fluidized bed polymerization reaction was stopped, and the distribution plate and fluidized loop pipeline in the reactor were stopped for inspection, and a thick polymer wall adhesion layer appeared.

[0049] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: It can be found from the embodiments and comparative examples that the method for preparing polyolefin elastomers of the present invention can further increase the rapid removal of heat generated by the polymerization reaction in the reactor, effectively prevent the polymer in the reactor from softening, agglomerating and clogging, reduce the content of polymer fine powder, and prevent the polymer fine powder from softening, scaling and clogging in the pipeline. In addition, the system of the present invention can solve the safety and stability problems existing in the production of polyolefin elastomers by gas phase polymerization process.

[0050] Although this specification includes many specific implementation details, these should not be interpreted as limiting the scope of any invention or the scope of protection claimed, but are mainly used to describe the features of the specific embodiments of specific inventions. Certain features described in multiple embodiments in this specification may also be implemented in combination in a single embodiment. On the other hand, the various features described in a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although features may work in certain combinations as described above and even initially claim protection, one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may point to a sub-combination or a variation of a sub-combination.

[0051] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring that these operations be performed in the particular order shown or performed sequentially, or requiring that all illustrated operations be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system modules and components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product, or packaged into multiple software products.

[0052] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In some implementations, multitasking and parallel processing may be advantageous.

[0053] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0054] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for continuously producing a polyolefin elastomer by a gas phase process, characterized in that: The method comprises the following steps: The ethylene, α-olefin, hydrogen, condensing agent and nitrogen are mixed to obtain a mixed material; The mixed material, catalyst and antistatic agent are polymerized to obtain polyolefin elastomer powder, polymerization block and unreacted material; The unreacted material is sequentially separated, subjected to primary heat exchange, pressurized and subjected to secondary heat exchange treatment, and then added to the mixed material; wherein, The polymerization reaction block is treated as waste, and the polyolefin elastomer powder is used as a product.

2. The method according to claim 1, characterized in that The separation includes primary separation and secondary separation, and the separation is used to remove the polyolefin elastomer powder entrained in the unreacted material. The pressurization treatment is carried out in a compressor.

3. The method according to claim 1, characterized in that: The α-olefin is 1-butene and / or 1-hexene; the condensing agent is selected from one or more of propane, pentane, cyclopentane, hexane, and cyclohexane; and / or, In the mixed material, the α-olefin accounts for 20-30% of the sum of the mass of the α-olefin and the ethylene, and the condensing agent accounts for 1.0-8.0% of the mass of the mixed material.

4. The method according to claim 1, characterized in that: The polymerization reaction pressure is 1.5-3.0 MPa, the reaction temperature is 35-70° C., and the reaction time is 8-18 h; and / or, The catalyst is a metallocene catalyst, the active components of the catalyst contain one or more of zirconocene chloride, methylaluminoxane, butylaluminoxane and hexylaluminoxane, and the yield of the catalyst is 5000-11000g product / g catalyst.

5. The method according to claim 1, characterized in that The antistatic agent comprises alkylbenzene sulfonic acid, 1-decene homopolymer and an organic solvent. The weight percentage of each component in the antistatic agent is: 4-10% of the alkylbenzene sulfonic acid, 10-15% of the 1-decene homopolymer and 77-85% of the organic solvent. The organic solvent is a C6-C8 alkane and / or cycloalkane. The added amount of the antistatic agent accounts for 0.0025-0.0085% of the ethylene.

6. The method according to claim 1, characterized in that The density of the polyolefin elastomer powder is 0.872-0.890 g / cm 3 , the melt mass flow rate is 0.5~15g / 10min, the content of particles with a particle size of 100~1000μm is 7.5~18.6%, and the content of particles with a particle size of 1600~4500μm is 27.1~48.5%.

7. A system for continuously producing polyolefin elastomers by a gas phase process, characterized in that: The method described in any one of claims 1 to 6 is used for operation, and the system includes: a primary heat exchange unit, a secondary heat exchange unit, a pressurizing unit, a gas-phase fluidized bed reaction unit, a separation unit, a material input unit and a material output unit; wherein, the inlet of the material output unit is connected to the outlet of the separation unit, the outlet of the material output unit is connected to the inlet of the primary heat exchange unit, the outlet of the primary heat exchange unit is connected to the inlet of the pressurizing unit, the outlet of the pressurizing unit is connected to the inlet of the secondary heat exchange unit, the outlet of the secondary heat exchange unit is connected to the inlet of the material input unit, the outlet of the material input unit is connected to the bottom inlet of the gas-phase fluidized bed reaction unit, the outlet of the gas-phase fluidized bed reaction unit is connected to the inlet of the separation unit, and the outlet of the separation unit is respectively connected to the side inlet of the gas-phase fluidized reaction unit and the inlet of the material output unit.

8. A system according to claim 7, characterized in that The gas-phase fluidized bed reaction unit is a gas-phase fluidized bed reactor. A catalyst injection port and an antistatic agent injection port are arranged at the fluidizing end of the gas-phase fluidized bed reactor. The antistatic agent injection port is located directly below the catalyst injection port. The injection direction of the catalyst is perpendicular to the direction of the gas-phase fluidized bed reactor. The injection direction of the antistatic agent injected into the antistatic agent injection port is at an angle of 30 to 60 degrees to the injection direction of the catalyst injected into the catalyst injection port.

9. The system according to claim 8, characterized in that The temperature monitor, pressure monitor and static monitor are independently arranged in the axial and radial directions of the gas phase fluidized bed reactor; the gas phase fluidization velocity of the lower part of the gas phase fluidized bed reactor is 0.40-0.80 m / s; The separation unit comprises a primary separation unit and a secondary separation unit, the separation unit is a separator, and the primary heat exchange unit and the secondary heat exchange unit are both heat exchangers.

10. The system according to claim 9, characterized in that In the gas-phase fluidized bed reactor, the pressure of the nitrogen backwash of the bed pressure difference monitoring instrument is 2.5~3.5MPa, the static electricity monitoring value in the gas-phase fluidized bed reactor is ±1000~±4000PA, and the discharge amount of the polymerization reaction block material in the bottom hopper of the gas-phase fluidized bed reactor is 0.5~5kg / 8h.

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