WO2011147539A1 - Olefin gas phase polymerisation - Google Patents
Olefin gas phase polymerisation Download PDFInfo
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- WO2011147539A1 WO2011147539A1 PCT/EP2011/002386 EP2011002386W WO2011147539A1 WO 2011147539 A1 WO2011147539 A1 WO 2011147539A1 EP 2011002386 W EP2011002386 W EP 2011002386W WO 2011147539 A1 WO2011147539 A1 WO 2011147539A1
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- 150000001336 alkenes Chemical class 0.000 title claims abstract description 23
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 title claims abstract description 21
- 239000007789 gas Substances 0.000 claims abstract description 91
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 83
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 71
- 229920000642 polymer Polymers 0.000 claims abstract description 68
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 56
- 230000008569 process Effects 0.000 claims abstract description 50
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 claims abstract description 40
- 239000000178 monomer Substances 0.000 claims abstract description 36
- 230000008961 swelling Effects 0.000 claims abstract description 34
- 239000000203 mixture Substances 0.000 claims abstract description 31
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 31
- 230000001737 promoting effect Effects 0.000 claims abstract description 31
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000001179 sorption measurement Methods 0.000 claims abstract description 27
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000011261 inert gas Substances 0.000 claims abstract description 17
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 claims abstract description 16
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 30
- 239000005977 Ethylene Substances 0.000 claims description 30
- 229930195733 hydrocarbon Natural products 0.000 claims description 24
- 150000002430 hydrocarbons Chemical class 0.000 claims description 24
- 239000003054 catalyst Substances 0.000 claims description 22
- 239000004215 Carbon black (E152) Substances 0.000 claims description 16
- 239000004711 α-olefin Substances 0.000 claims description 12
- 229920006395 saturated elastomer Polymers 0.000 claims description 11
- -1 polyethylene Polymers 0.000 claims description 10
- 239000004698 Polyethylene Substances 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 229920000573 polyethylene Polymers 0.000 claims description 8
- 238000009826 distribution Methods 0.000 claims description 6
- 239000011859 microparticle Substances 0.000 claims description 4
- 238000006116 polymerization reaction Methods 0.000 description 35
- 238000004519 manufacturing process Methods 0.000 description 30
- 239000012071 phase Substances 0.000 description 25
- 239000007788 liquid Substances 0.000 description 21
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 15
- 239000002245 particle Substances 0.000 description 15
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 11
- 238000001816 cooling Methods 0.000 description 9
- 238000009835 boiling Methods 0.000 description 6
- 238000012685 gas phase polymerization Methods 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 150000002431 hydrogen Chemical class 0.000 description 5
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 5
- 239000007791 liquid phase Substances 0.000 description 4
- 230000000379 polymerizing effect Effects 0.000 description 4
- 230000001174 ascending effect Effects 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- YWAKXRMUMFPDSH-UHFFFAOYSA-N pentene Chemical compound CCCC=C YWAKXRMUMFPDSH-UHFFFAOYSA-N 0.000 description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000003134 recirculating effect Effects 0.000 description 2
- OJOWICOBYCXEKR-KRXBUXKQSA-N (5e)-5-ethylidenebicyclo[2.2.1]hept-2-ene Chemical compound C1C2C(=C/C)/CC1C=C2 OJOWICOBYCXEKR-KRXBUXKQSA-N 0.000 description 1
- AFFLGGQVNFXPEV-UHFFFAOYSA-N 1-decene Chemical compound CCCCCCCCC=C AFFLGGQVNFXPEV-UHFFFAOYSA-N 0.000 description 1
- HECLRDQVFMWTQS-RGOKHQFPSA-N 1755-01-7 Chemical compound C1[C@H]2[C@@H]3CC=C[C@@H]3[C@@H]1C=C2 HECLRDQVFMWTQS-RGOKHQFPSA-N 0.000 description 1
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 1
- INYHZQLKOKTDAI-UHFFFAOYSA-N 5-ethenylbicyclo[2.2.1]hept-2-ene Chemical compound C1C2C(C=C)CC1C=C2 INYHZQLKOKTDAI-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 239000004129 EU approved improving agent Substances 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 206010035148 Plague Diseases 0.000 description 1
- 241000607479 Yersinia pestis Species 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 150000001924 cycloalkanes Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000368 destabilizing effect Effects 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000009790 rate-determining step (RDS) Methods 0.000 description 1
- 238000009751 slip forming Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/34—Polymerisation in gaseous state
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
Definitions
- the invention relates to a process for the polymerisation of olefin monomers, preferably ethylene monomers, in a gas phase polymerization process in a fluidised bed reactor.
- Olefin polymerization is a very exothermic reaction. Heat needs to be removed continuously so as to keep the temperature in the reactor at the desired level. Such removal may be effected via the gas stream which leaves the reactor at a higher temperature than that at which it is supplied to the reactor. In gas phase polymerization the removal of heat from the bed of growing polymer tends to be a rate limiting step.
- gas phase polymerization processes typically run continuously, therefore the temperature of the fluidized bed reactor is controlled to an essentially isothermal level through continuously removing the heat of polymerization by circulating the gas exiting from the fluidized bed to a condenser/heat exchanger outside the reactor and recirculating the cooled gas stream back into the reactor.
- the temperature of the recirculating stream introduced or recycled into the fluidized bed polymerization reactor is above the dew point temperature, substantially no liquid is present. This process is known as the "dry mode" process.
- One method to maximize the ability of heat removal is, throughout the operation, to reduce to the lowest possible value the temperature of the gaseous feed stream into the reactor.
- a two phase mixture is directed into the fluidized bed as a fluidizing medium, the liquid portion of which vaporizes when it is exposed to the heat of the reactor.
- Fluid is formed by cooling the recycle stream below the dew point temperature, thereby converting a portion of the gas into a liquid, and the cooled recycle stream is introduced into the fluidized bed polymerization reactor.
- the objective is to take advantage of the cooling effect brought about by the vaporization, i.e., by bringing the temperature of the fluidized bed down to a point where degradation of the polymer and the catalyst are avoided and agglomeration of the polymer and chunking are prevented.
- the liquid phase is provided by a portion of the recycle gases, which includes monomers and low boiling liquid hydrocarbons, inert to the reaction conditions needed for polymerization, and condensation.
- Condensed mode fluidized bed reactor polymerization processes are disclosed in for example US 4543399 and US 4588790. These publications describe the introduction of an inert liquid into the recycle stream to increase the dew point temperature of the recycle stream and allowing the process to operate at levels of up to 17.4% liquid by weight, based on the total weight of the cooled recycle stream.
- a condensed mode process is advantageous because its ability to remove greater quantities of heat generated by polymerization increases the polymer production capacity of a fluidized bed polymerization reactor.
- a commonly used liquid hydrocarbon is isopentane, which boils at about 27 °C, and consequently becomes a vapor in the recycle line in view of the heat present in the recycle gases.
- the recycle gases leave the reactor are cooled, and then condensed to the extent that a vapor phase and liquid phase are formed.
- the velocity of the recycled gas/liquid mixture should be sufficient to support the fluidized bed, but slow enough to avoid excessive entrainment of fines.
- the cooling capacity should be sufficient to improve the production rate in terms of space/time/yield.
- Condensed and super condensed mode processes have been limited due to several factors including only an estimate of the amount of liquid entering the bed was controlled /monitored.
- the negatives reside in the limit placed upon the production rate, i.e., space/time/yield, which is influenced by the maximum rate at which heat can be removed from the reactor; the introduction of hydrocarbons other than monomers, which, although considered inert, can affect the polymer morphology and the static, chunking, and sheeting, which plague many polymerization runs; flooding and frothing at the bottom of the reactor due to too much liquid; and the requirement for additional cooling and condensing equipment for converting the recycle stream to the gas/liquid mixture.
- Fraser et al. discloses in "Manufacturing efficiencies from metallocene catalysis in gas phase polyethylene production" (1997, Univation Technologies) the general concept of the olefin gas phase process.
- the feed stream passes through a fluidized or stirred bed of growing polymer particles.
- the growing polymer particles are fluidised by a recycle gas stream of monomer, co-monomer, hydrogen, nitrogen and inert condensing gas.
- the cycle gas flow provides monomer and co-monomer for polymerization, agitates the bed and also removes the heat of polymerization.
- the cycle gas exits the top of the reactor and is then compressed through a compressor and cooled via a heat exchanger before being fed into the bottom of the fluidised bed.
- the recycle stream is made up with additional feed stream and returned to the bed of growing polymer.
- the monomer in the feed stream contacts the catalyst in the growing polymer particles and is polymerized.
- polymerisation is a vertical elongated reactor in which a bed of polymer particles is maintained in fluidised condition with the aid of an ascending gas feed stream which contains the gaseous monomer(s) to be polymerised.
- the reactor comprises a reaction zone which is confined at the underside by a gas distribution plate and at the top side by a virtual end surface, in which the fluidised bed is maintained between the underside and the top side and in which at least part of the gaseous stream withdrawn from the top of the reactor is cooled to a point where the stream partially condenses into a liquid, and in which at least part of the resulting two-phase stream is recycled to the reactor via an inlet which terminates in the reactor below the gas distribution plate.
- the ascending gas stream may contain an inert gas and for example hydrogen as a chain length regulator.
- the inert gas is added to control the dew point of the gas mixture.
- Suitable inert gases include for example nitrogen and inert hydrocarbons such as (iso)butane, (iso)pentane and (iso)hexane.
- the inert gas may be added to the gas stream as a gas or, in condensed form, as a liquid.
- the gas stream is discharged through the top of the reactor and, after certain processing operations, fresh monomer is added to it to make up for the monomer(s) consumed in the polymerisation, and then the gas stream is again supplied to the reactor as (a portion of) the ascending gas stream in order to maintain the bed.
- a catalyst is also added to the bed.
- EP1 196238 discloses a process for the gas phase polymerisation of one or more olefin monomers in a fluidised bed reactor, which reactor comprises a reaction zone which is confined at the underside by a gas distribution plate and at the top side by a virtual end surface, in which a fluidised bed is maintained between the underside and the top side, and in which at least part of the gaseous stream withdrawn from the top of the reactor is cooled and in which at least part of the resulting two-phase stream is recycled to the reactor and wherein the gas stream comprises an inert gas.
- the conventional fluidized bed reactors used in gas-phase olefin polymerization may have a cylindrical shaped fluidized bed section and an enlarged conical entrainment disengaging section.
- fresh polymer particles are produced by catalytic polymerization of olefin, eg ethylene.
- Such polymer particles are projected upward into the disengaging section through the flowing gas and most of these particles return to the fluidized bed by gravity as their velocity decreases in the disengaging section.
- some of fine particles "fines" are elutriated out of the projected particles and do not return to the fluidized bed by gravity. Such fines either leave with the flowing gas through the reactor outlet or accumulate in the disengaging section.
- polymer properties for example a high polymer particle density, a high polymer bulk density, a high catalyst productivity and improved polymer morphology should be obtained.
- This object is achieved with a process for the gas phase polymerisation of one or more olefin monomers in a fluidised bed reactor in a dry mode or in a (super) condensed mode with a gas stream comprising an inert gas,
- ethylene and alpha olefins local concentrations at the growing polymer micro-particle level where sorption of such components into the polyethylene increases the local concentration of ethylene and/or alpha-olefins in terms of micro-conditions surrounding the catalyst active sites and
- viscoelastic properties modifying agent developed instantaneously during polymer growth, by swelling and plasticizing the polymer formed during growth and which agent influences the characteristics of the crystalline phase.
- the process takes place in a reactor which comprises a reaction zone which is confined at the underside by a gas distribution plate and at the top side by a virtual end surface, in which a fluidised bed is maintained between the underside and the top side, and in which at least part of the gaseous stream withdrawn from the top of the reactor is cooled and in which at least part of the resulting two-phase stream is recycled to the reactor and wherein the gas stream comprises an inert gas, comprising a mixture of inert components:
- the recycle stream is made up with additional feed stream and returned to the bed of growing polymer.
- the feed stream in the recycle stream comprises olefin monomers and the mixture of inert components.
- the olefin is ethylene.
- the amount of ethylene in the feed stream ranges between 50 % by weight and 95% by weight of the total amount of olefin monomers.
- Suitable co-monomers include for example 1 -butene, 1 -hexene and propylene.
- the process according to the invention results in an improved process especially in terms of space/time/yield and at the same time enabling a broader range of operating conditions of the fluidized bed reactor polymerization process.
- the gas phase polymerisation takes place via the (super) condensed mode process.
- the inert gas comprises
- the inert components are saturated compounds.
- the gas heat capacity increasing agent in the feed stream to a gas phase reactor regulates the dew point and at the same time improves the vapor stream heat capacity.
- the gas heat capacity increasing agent is a saturated (C2-C4) hydrocarbon or a mixture of at least two different saturated (C 2 -C 4 )
- the gas heat capacity increasing agent is a saturated
- gas heat capacity increasing agent is ethane.
- the sorption promoting agent acts as promoting agent of the ethylene and alpha olefins local concentrations at the growing polymer micro-particle level where sorption of such components into the polyethylene increases the local concentration of ethylene and/or alpha-olefins in terms of micro-conditions surrounding the catalyst active sites. This physical phenomenon is known as co-solubility.
- the sorption promoting agent is a saturated (C 4 -C 7 )
- hydrocarbon or a mixture of at least two different saturated (C 4 -C 7 )
- the sorption promoting agent is the (C ) hydrocarbon n- butane.
- the polymer swelling agent acts as a polymer physical and viscoelastic properties modifying agent, developed instantaneously during polymer growth, by swelling and plasticizing the polymer formed during growth. Furthermore the polymer swelling agent influences the characteristics of the crystalline phase, such as crystallinity, lamellar thickness, and the interfacial structure of crystallites. Additionally the polymer swelling agent functions as a delaying agent for the crystallization kinetics during polymer growth. Accordingly the swelling agent reduces the production of fines during polymerization and additionally the swelling agent increases the particle density through controlling the catalyst fragmentation. Generally the applied swelling agents have a normal boiling point higher than 40 °C.
- the polymer swelling agent is a saturated (C 5 -C 2 o)
- hydrocarbon or a mixture of at least two different saturated (C 5 -C 2 o)
- the polymer swelling agent is n-pentane or iso-pentane. It is possible to apply for example iso-pentane as the sorption promoting agent and also as swelling promoting agent. In this case iso-pentane may be present in an amount between for example 1 .1 and 60 % by mole.
- the mixture comprises
- the mixture comprises
- the polymerization process according to the present invention combines running the fluidized bed reactor with cooling capacity sufficient to improve the production rate in terms of space/time/yield and at the same time enabling a broader range of operating conditions of a dry and condensed mode fluidized bed reactor polymerization method regardless of the type of catalyst used and polymer properties with high polymer particle density, polymer bulk density, promoted catalyst productivity and improved polymer morphology process for the reduction of powder fines in a fluid bed polyethylene process.
- the process according to the invention results in a reduction of fines to a low level in for example the polyethylene production process of a fluid bed reactor through the introduction of promoting agents of the ethylene and alpha olefins local concentrations at the growing polymer micro-particle level and through the introduction at the same time agents of instantaneous viscoelastic local properties improving agents while furthermore at the same time the maintenance of the operation without stability problems in the reactor bed or of entrainment of polymer particles is secured.
- the process according to the present invention comprises
- compositions maximize the heat transport properties both microscopically (at the particle level) and macroscopically (at the reactor level).
- Macroscopic implies the total volume of the reactor whereas microscopic refers to the immediate vicinity around the catalytic sites where polymerization takes place.
- the use of the swelling agent results in improved viscoelastic properties in addition to better heat removal through all components and consequently the process according to the present invention results in a reduced amount of fines.
- the process according to the present invention is suitable for the manufacture of polyolefins in the gas phase by the polymerisation of one or more olefin monomers.
- the polymers may be homopolymers and copoymers of ethylene and/or propylene or copolymers of ethylene or propylene with one or more C2-C 8 alpha-olefins such as for example ethylene, propylene, butene-1 , pentene-1 , hexene-1 , 4-methylpentene-1 , and octene-1.
- decene-1 or dienes for example 1 ,4-butadiene, 1 ,6-hexadiene, dicyclopentadiene, ethylidene norbornene and vinyl norbornene may also be applied.
- the process is an ethylene homo polymerization or an ethylene - alpha-olefin co-polymerization process.
- the pressure of the polymerisation process ranges between 0.5 and 10 MPa and the temperature ranges between 30°C and 130°C.
- a catalyst is also added to the bed. During the process, under the influence of the catalyst present, fresh polymer is continuously formed and at the same time polymer that has formed is withdrawn from the bed, with the bed volume and mass being kept substantially constant.
- - l i lt is another advantage of the present invention that the object is obtained regardless of the applied type of catalyst.
- the polymerisation reaction may be carried out in the presence of any known suitable catalyst system for the gas phase polymerisation for example a catalyst system of the Ziegler-Natta type, a chromium based catalyst system and a metallocene based catalyst system.
- a catalyst system of the Ziegler-Natta type for example a catalyst system of the Ziegler-Natta type, a chromium based catalyst system and a metallocene based catalyst system.
- the catalyst may also be in the form of a prepolymer powder prepared in a prepolymerisation stage with the aid of a catalyst system described above.
- the prepolymerisation may be carried out by any known process, for example, polymerisation in a liquid hydrocarbon diluent or in the gas phase using a batch process, a semi-continuous process or a continuous process.
- US2005/182207 discloses a continuous gas fluidized bed polymerization process for the production of a polymer from a monomer including continuously passing a gaseous stream comprising the monomer through a fluidized bed reactor in the presence of a catalyst under reactive conditions; withdrawing a polymeric product and a stream comprising unreacted monomer gases; cooling said stream comprising unreacted monomer gases to form a mixture comprising a gas phase and a liquid phase and reintroducing said mixture into said reactor with sufficient additional monomer to replace that monomer polymerized and withdrawn as the product, wherein said liquid phase is vaporized, and wherein the stream comprises at least two inert condensing agents selected from the group consisting of alkanes and cycloalkanes.
- US 2005/0182207 applies at least two inert condensing agents of normal boiling point less than 40 °C.
- US6759489 discloses a continuous gas fluidized bed methods for making a polymer featuring a condensing agent in a recycle stream and also to methods for monitoring and providing continuity in a gas fluidized bed method for making a polymer featuring a condensing agent in a recycle stream.
- US5436304 relates to a process for polymerizing alpha-olefins in a gas phase reactor at significantly higher production rates than herefore envisaged.
- the invention is directed toward a process for polymerizing alpha-olefins in a gas phase reactor having a fluidized bed and a fluidizing medium where the level of liquid in the fluidizing medium is greater than 15 weight percent based on the total weight of the fluidizing medium.
- US5436304 relates to a method for determining stable operating conditions of a gas phase fluidized bed polymerization reactor by identifying a property useful to determine stability of a fluidized bed and controlling the composition of a fluidizing medium or recycle stream to establish a range of values for the property to maintain the stable operating condition.
- US5352749 discloses a process for polymerizing alpha-olefin(s) in a gas phase reactor having a fluidized bed and a fluidizing medium wherein the fluidizing medium serves to control the cooling capacity of said reactor, the improvement comprising employing a level of liquid in the fluidizing medium entering the reactor which is in the range of from 17.4 to 50 weight percent based on the total weight of the fluidizing medium and maintaining the ratio of fluidized bulk density to settled bulk density above 0.59.
- a polymerization process in fluidized bed was used to carry out the polymerization of ethylene and 1 -hexene in the non condensed dry mode in accordance with the conditions as disclosed in Example 9 of US 4588790.
- Example I iso-pentane was replaced partially (about 25 %) by n- pentane.
- n-pentane has a higher solubility than iso-pentane in polyethylene by about 12% and n-pentane has higher heat transfer capabilities than iso-pentane by about 4 %.
- Example II iso-pentane was replaced by a mixture of n-butane and n- pentane.
- n-pentane has higher solubility than iso-pentane in polyethylene by about 12% and n-butane has a lower solubility by about 40 %
- n- pentane has higher heat transfer capabilities than iso-pentane by about 4 %
- n- butane has much lower boiling point of -0.6 °C compared to a boiling point of 27.8 °C for iso-pentane and with approximately similar heat transfer capabilities as iso-pentane.
- Example 9 A polymerization process in fluidized bed was carried out in accordance with the disclosure of Example 9 in US 4588790.
- the examples show an increase in the production rate of about 8 and 11 percent, respectively, obtained in condensed mode of operation by replacing more than 40% of nitrogen by ethane (Example III) and more than 90% of nitrogen by ethane (Example IV).
- Comparative Example C resulted in a remarkable reduction in the dew point of the inlet recycle stream which enabled lowering the recycle stream inlet temperature which contributed to further improvement of the production rate.
- Example VII shows an increase in the production rate by replacing about
- Example VIII shows an increase in the production rate of about 70 percent by replacing more than 50% of nitrogen by ethane, and the use of about 39% of isopentane (compared to Comparative Example C) with about 25% of iso-pentane as n-pentane.
- n-Butane 0.0020 0.0020 — — — — n-Pentane (polymer swelling agent) — — — 0.020 0.025 0.018
- a polymerization process in fluidized bed was used to polymerize ethylene and 1 -butene in the condensed mode in accordance with the disclosure of example 10. a in US 4588790. Table 4 shows that when comparing the Comparative Example D, with Example IX and Example X an increase in the production rate of about 1 1 and 37 percent, respectively, was obtained.
- Reactor inlet Pressure (psig) 276.2 276.2 276.2
- n-Butane (sorption promoting agent) — — 0.1200 — n-Pentane (polymer swelling agent) — — 0.0120 —
- a polymerization process in fluidized bed was carried out to polymerize ethylene and 1 -hexene in the condensed mode in accordance with the reaction conditions as disclosed in Example 3 in WO 99/06451 .
- Comparing the Comparative Example F and Examples XIV, XV and XVI in Table 6 shows an increase in the production rate of about 22, 32 and 43
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- Polymerisation Methods In General (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
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BR112012029957A BR112012029957A2 (en) | 2010-05-27 | 2011-05-12 | gas phase olefin polymerization |
EP11720388.5A EP2576636B1 (en) | 2010-05-27 | 2011-05-12 | Olefin gas phase polymerisation |
US13/699,080 US8669334B2 (en) | 2010-05-27 | 2011-05-12 | Olefin gas phase polymerisation |
CN201180026135.XA CN102947351B (en) | 2010-05-27 | 2011-05-12 | Olefin gas phase polymerisation |
JP2013511569A JP5787379B2 (en) | 2010-05-27 | 2011-05-12 | Olefin gas phase polymerization |
EA201201610A EA022659B1 (en) | 2010-05-27 | 2011-05-12 | Process for olefin gas phase polymerisation |
US14/167,342 US20140148563A1 (en) | 2010-05-27 | 2014-01-29 | Olefin gas phase polymerisation |
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US14/167,342 Continuation US20140148563A1 (en) | 2010-05-27 | 2014-01-29 | Olefin gas phase polymerisation |
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WO2015078815A1 (en) * | 2013-11-29 | 2015-06-04 | Saudi Basic Industries Corporation | Process for continuous polymerization of olefin monomers in a reactor |
WO2015078816A1 (en) * | 2013-11-29 | 2015-06-04 | Saudi Basic Industries Corporation | Multi-zone reactor for continuous polymerization of alpha olefin monomers |
WO2015078814A1 (en) * | 2013-11-29 | 2015-06-04 | Saudi Basic Industries Corporation | Process for continuous polymerization of olefin monomers in a reactor |
WO2016086006A1 (en) * | 2014-11-25 | 2016-06-02 | Univation Technologies, Llc | Methods of changing polyolefin production rate with the composition of the induced condensing agents |
WO2016182920A1 (en) | 2015-05-08 | 2016-11-17 | Exxonmobil Chemical Patents Inc. | Polymerization process |
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WO2022268951A1 (en) * | 2021-06-24 | 2022-12-29 | Borealis Ag | Use of a swelling agent in multi-stage polyolefin production |
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EA022659B1 (en) * | 2010-05-27 | 2016-02-29 | Сауди Бейсик Индастриз Корпорейшн (Сабик) | Process for olefin gas phase polymerisation |
CN111269491B (en) * | 2020-03-24 | 2021-06-22 | 浙江大学 | Olefin gas-phase polymerization method |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4543399A (en) | 1982-03-24 | 1985-09-24 | Union Carbide Corporation | Fluidized bed reaction systems |
US4588790A (en) | 1982-03-24 | 1986-05-13 | Union Carbide Corporation | Method for fluidized bed polymerization |
US5352749A (en) | 1992-03-19 | 1994-10-04 | Exxon Chemical Patents, Inc. | Process for polymerizing monomers in fluidized beds |
US5436304A (en) | 1992-03-19 | 1995-07-25 | Exxon Chemical Patents Inc. | Process for polymerizing monomers in fluidized beds |
WO1999006451A1 (en) | 1997-07-31 | 1999-02-11 | Union Carbide Chemicals & Plastics Technology Corporation | Control of gas phase polymerization reactions |
EP1196238A1 (en) | 1999-05-18 | 2002-04-17 | Dsm N.V. | Fluidised bed polymerisation |
US6759489B1 (en) | 2003-05-20 | 2004-07-06 | Eastern Petrochemical Co. | Fluidized bed methods for making polymers |
US20050182207A1 (en) | 2003-12-23 | 2005-08-18 | Diwaker Singh | Gas-phase process |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DZ520A1 (en) * | 1982-03-24 | 2004-09-13 | Union Carbide Corp | Improved process for increasing the space-time yield of an exothermic polymerization reaction in a fluidized bed. |
JP3180305B2 (en) * | 1993-08-27 | 2001-06-25 | 宇部興産株式会社 | Gas phase polymerization of olefins |
EP1001020A4 (en) | 1997-07-29 | 2005-03-02 | Sumitomo Electric Industries | Antihuman pre-b cell receptor antibodies |
JP3821927B2 (en) * | 1997-09-29 | 2006-09-13 | 三井化学株式会社 | Method for producing linear low density polyethylene |
BR9906019B1 (en) * | 1999-12-30 | 2012-02-22 | process for polymerization and copolymerization of olefinic monomers in gas phase reactors. | |
DE10139477A1 (en) * | 2001-08-10 | 2003-02-20 | Basell Polyolefine Gmbh | Optimization of heat removal in a gas phase fluidized bed process for polyethylene production using ethane to increase the heat capacity of the fluidized bed gas |
BRPI0910770A2 (en) * | 2008-04-22 | 2015-09-29 | Univation Tech Llc | reactor system and processes for their use |
US20120283369A1 (en) * | 2009-12-16 | 2012-11-08 | Basell Polyolefine Gmbh | Polymerization process in the presence of an antistatic agent |
EA022659B1 (en) * | 2010-05-27 | 2016-02-29 | Сауди Бейсик Индастриз Корпорейшн (Сабик) | Process for olefin gas phase polymerisation |
-
2011
- 2011-05-12 EA EA201201610A patent/EA022659B1/en not_active IP Right Cessation
- 2011-05-12 EP EP11720388.5A patent/EP2576636B1/en active Active
- 2011-05-12 JP JP2013511569A patent/JP5787379B2/en active Active
- 2011-05-12 CN CN201180026135.XA patent/CN102947351B/en active Active
- 2011-05-12 BR BR112012029957A patent/BR112012029957A2/en not_active Application Discontinuation
- 2011-05-12 US US13/699,080 patent/US8669334B2/en active Active
- 2011-05-12 WO PCT/EP2011/002386 patent/WO2011147539A1/en active Application Filing
-
2014
- 2014-01-29 US US14/167,342 patent/US20140148563A1/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4543399A (en) | 1982-03-24 | 1985-09-24 | Union Carbide Corporation | Fluidized bed reaction systems |
US4588790A (en) | 1982-03-24 | 1986-05-13 | Union Carbide Corporation | Method for fluidized bed polymerization |
US5352749A (en) | 1992-03-19 | 1994-10-04 | Exxon Chemical Patents, Inc. | Process for polymerizing monomers in fluidized beds |
US5436304A (en) | 1992-03-19 | 1995-07-25 | Exxon Chemical Patents Inc. | Process for polymerizing monomers in fluidized beds |
WO1999006451A1 (en) | 1997-07-31 | 1999-02-11 | Union Carbide Chemicals & Plastics Technology Corporation | Control of gas phase polymerization reactions |
EP1196238A1 (en) | 1999-05-18 | 2002-04-17 | Dsm N.V. | Fluidised bed polymerisation |
US6759489B1 (en) | 2003-05-20 | 2004-07-06 | Eastern Petrochemical Co. | Fluidized bed methods for making polymers |
US20050182207A1 (en) | 2003-12-23 | 2005-08-18 | Diwaker Singh | Gas-phase process |
Non-Patent Citations (1)
Title |
---|
FRASER ET AL.: "Manufacturing efficiencies from metallocene catalysis in gas phase polyethylene production", UNIVATION TECHNOLOGIES, 1997 |
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WO2022268951A1 (en) * | 2021-06-24 | 2022-12-29 | Borealis Ag | Use of a swelling agent in multi-stage polyolefin production |
Also Published As
Publication number | Publication date |
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US20130066027A1 (en) | 2013-03-14 |
EA022659B1 (en) | 2016-02-29 |
EP2576636B1 (en) | 2019-06-26 |
US8669334B2 (en) | 2014-03-11 |
CN102947351A (en) | 2013-02-27 |
US20140148563A1 (en) | 2014-05-29 |
JP5787379B2 (en) | 2015-09-30 |
BR112012029957A2 (en) | 2016-09-20 |
WO2011147539A8 (en) | 2012-12-27 |
JP2013527292A (en) | 2013-06-27 |
EP2576636A1 (en) | 2013-04-10 |
CN102947351B (en) | 2014-09-17 |
EA201201610A1 (en) | 2013-05-30 |
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