CN111848841A - Propylene polymerization method - Google Patents
Propylene polymerization method Download PDFInfo
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- CN111848841A CN111848841A CN201910356724.2A CN201910356724A CN111848841A CN 111848841 A CN111848841 A CN 111848841A CN 201910356724 A CN201910356724 A CN 201910356724A CN 111848841 A CN111848841 A CN 111848841A
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- 238000006116 polymerization reaction Methods 0.000 title claims abstract description 79
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 title claims abstract description 76
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims description 65
- 239000007789 gas Substances 0.000 claims abstract description 101
- 238000006243 chemical reaction Methods 0.000 claims abstract description 93
- 239000011344 liquid material Substances 0.000 claims abstract description 68
- 229920001155 polypropylene Polymers 0.000 claims abstract description 63
- 239000001257 hydrogen Substances 0.000 claims abstract description 62
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 62
- 239000007788 liquid Substances 0.000 claims abstract description 56
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 54
- 238000007334 copolymerization reaction Methods 0.000 claims abstract description 49
- 238000009826 distribution Methods 0.000 claims abstract description 28
- 238000000926 separation method Methods 0.000 claims abstract description 21
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims description 49
- 230000008569 process Effects 0.000 claims description 34
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 claims description 29
- 239000003054 catalyst Substances 0.000 claims description 25
- 238000003860 storage Methods 0.000 claims description 25
- 239000007787 solid Substances 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 19
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
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- 238000005243 fluidization Methods 0.000 claims description 13
- 239000000178 monomer Substances 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- AFFLGGQVNFXPEV-UHFFFAOYSA-N 1-decene Chemical compound CCCCCCCCC=C AFFLGGQVNFXPEV-UHFFFAOYSA-N 0.000 claims description 6
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 claims description 6
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- 239000004711 α-olefin Substances 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 238000009833 condensation Methods 0.000 claims description 3
- 230000005494 condensation Effects 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
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- 238000006555 catalytic reaction Methods 0.000 claims description 2
- 238000007599 discharging Methods 0.000 claims description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 2
- 238000005507 spraying Methods 0.000 abstract description 6
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- 239000012530 fluid Substances 0.000 description 20
- 229920000642 polymer Polymers 0.000 description 10
- 150000001336 alkenes Chemical class 0.000 description 9
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 8
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 8
- 239000002994 raw material Substances 0.000 description 8
- 229910052782 aluminium Inorganic materials 0.000 description 7
- 239000012071 phase Substances 0.000 description 7
- 238000012512 characterization method Methods 0.000 description 6
- 150000002431 hydrogen Chemical class 0.000 description 6
- 229920000098 polyolefin Polymers 0.000 description 6
- VOITXYVAKOUIBA-UHFFFAOYSA-N triethylaluminium Chemical compound CC[Al](CC)CC VOITXYVAKOUIBA-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 229920001577 copolymer Polymers 0.000 description 5
- JWCYDYZLEAQGJJ-UHFFFAOYSA-N dicyclopentyl(dimethoxy)silane Chemical compound C1CCCC1[Si](OC)(OC)C1CCCC1 JWCYDYZLEAQGJJ-UHFFFAOYSA-N 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000002685 polymerization catalyst Substances 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- 229910010062 TiCl3 Inorganic materials 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 229910001873 dinitrogen Inorganic materials 0.000 description 4
- 229910001629 magnesium chloride Inorganic materials 0.000 description 4
- 229920001707 polybutylene terephthalate Polymers 0.000 description 4
- 229910052719 titanium Inorganic materials 0.000 description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 3
- CMAOLVNGLTWICC-UHFFFAOYSA-N 2-fluoro-5-methylbenzonitrile Chemical compound CC1=CC=C(F)C(C#N)=C1 CMAOLVNGLTWICC-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 239000004803 Di-2ethylhexylphthalate Substances 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000003342 alkenyl group Chemical group 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 125000003710 aryl alkyl group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- 150000001733 carboxylic acid esters Chemical class 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 229940018560 citraconate Drugs 0.000 description 1
- HNEGQIOMVPPMNR-IHWYPQMZSA-N citraconic acid Chemical compound OC(=O)C(/C)=C\C(O)=O HNEGQIOMVPPMNR-IHWYPQMZSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 125000000753 cycloalkyl group Chemical group 0.000 description 1
- SJJCABYOVIHNPZ-UHFFFAOYSA-N cyclohexyl-dimethoxy-methylsilane Chemical compound CO[Si](C)(OC)C1CCCCC1 SJJCABYOVIHNPZ-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- YNLAOSYQHBDIKW-UHFFFAOYSA-M diethylaluminium chloride Chemical compound CC[Al](Cl)CC YNLAOSYQHBDIKW-UHFFFAOYSA-M 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- JGHYBJVUQGTEEB-UHFFFAOYSA-M dimethylalumanylium;chloride Chemical compound C[Al](C)Cl JGHYBJVUQGTEEB-UHFFFAOYSA-M 0.000 description 1
- SNRUBQQJIBEYMU-UHFFFAOYSA-N dodecane Chemical group CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 229910052809 inorganic oxide Inorganic materials 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000012968 metallocene catalyst Substances 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 150000003003 phosphines Chemical class 0.000 description 1
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229920005629 polypropylene homopolymer Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 229930195734 saturated hydrocarbon Natural products 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 150000004756 silanes Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000011949 solid catalyst Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-L succinate(2-) Chemical compound [O-]C(=O)CCC([O-])=O KDYFGRWQOYBRFD-UHFFFAOYSA-L 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 150000003623 transition metal compounds Chemical class 0.000 description 1
- MCULRUJILOGHCJ-UHFFFAOYSA-N triisobutylaluminium Chemical compound CC(C)C[Al](CC(C)C)CC(C)C MCULRUJILOGHCJ-UHFFFAOYSA-N 0.000 description 1
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 description 1
- LFXVBWRMVZPLFK-UHFFFAOYSA-N trioctylalumane Chemical compound CCCCCCCC[Al](CCCCCCCC)CCCCCCCC LFXVBWRMVZPLFK-UHFFFAOYSA-N 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
Images
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
- C08F10/00—Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F10/04—Monomers containing three or four carbon atoms
- C08F10/06—Propene
-
- 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
- C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F110/04—Monomers containing three or four carbon atoms
- C08F110/06—Propene
-
- 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
- C08F210/04—Monomers containing three or four carbon atoms
- C08F210/06—Propene
Abstract
The present invention relates to a propylene polymerization process comprising: carrying out propylene polymerization reaction in a polymerization reactor, condensing circulating gas output by the polymerization reactor, and carrying out gas-liquid separation, and independently spraying or not spraying the obtained different types of liquid materials at the same axial direction and different heights of the side wall of the reactor or independently spraying the different types of liquid materials at intervals, so that the copolymerization and homopolymerization of propylene, copolymerization and copolymerization are switched in the fluidized bed reactor; when the liquid material is sprayed into the reactor through the side wall of the reactor, a plurality of reaction zones with different hydrogen concentrations and comonomer concentrations are formed in the radial direction in the fluidized bed reactor. The difference between the radial concentration and the temperature is more obvious and stable; the heat removal capacity of the reactor is improved; propylene polymer products with high performance added value can be produced. The prepared propylene polymer product has wide molecular weight distribution, density range, melt index range and the like.
Description
Technical Field
The invention relates to a propylene polymerization method, in particular to a propylene polymerization method for alternately spraying liquid materials into a reactor to realize the switching of copolymerization and homopolymerization, copolymerization and copolymerization of propylene, and a method for preparing a propylene polymer by causing the radial concentration difference inside the reactor because the spraying positions of the liquid materials are positioned at the same axial direction and different heights of the side wall of the reactor.
Background
As is well known, polypropylene is a thermoplastic obtained by polymerizing propylene, and copolymers obtained by copolymerizing propylene with a small amount of ethylene, alpha-olefin, etc. are also industrially included. Polypropylene has many excellent characteristics and good processability, so that it has a wide range of applications, and the wide range of raw material sources and low price make polypropylene increasingly widely used. Improvements and improvements in propylene polymer properties remain a constant goal of the researchers.
In the conventional propylene polymerization process, a Unipol polypropylene process, a gas phase fluidized bed polypropylene process, is typically employed. Although the traditional Unipol polypropylene process has the advantages of simple process flow, less equipment quantity, high safety and reliability of device production and high economical efficiency of device operation, the production capacity is limited by the reaction heat in a fluidized bed, and the produced product has a relatively simple structure and a single function and lacks of relatively high performance added value. US patent US 4588790 discloses a process for producing polymers operating in a gas phase fluidized bed condensing mode by introducing a readily condensable liquid, i.e. a condensing medium (typically a copolymerized higher alpha-olefin or an inert saturated hydrocarbon), which is vaporized in a fluidized bed reactor to enhance removal of the heat of polymerization, thereby doubling the space time yield of the fluidized bed reactor.
US patent US 6815512 and US patent US 7025938 disclose a process for producing polyolefins using a condensing mode in a fluidized bed. The process emphasizes that the condensed recycle gas is separated in a separator into two parts, one part of the stream containing a small amount of liquid is injected into the bottom of the fluidized bed and the other part of the stream containing a large amount of liquid is injected at a location above the product outflow conduit of the fluidized bed. The location of the injection point reduces the liquid content in the product discharge tank while improving the discharge cycle time and more effectively protecting the monomer and other materials that may be lost in the discharge system. Although both of the above patents suggest producing polyolefins in the condensing mode, increasing the space-time yield of the reaction system at a given reactor volume, there is no mention of how to improve the properties of propylene polymers and how to produce high value-added polymers.
Chinese patent CN 104628904A discloses a method for preparing olefin polymer by using multiple temperature reaction zones, which utilizes the spraying of a circulating medium at the side wall above a distribution plate of a reactor to form multiple olefin polymerization reaction zones with different temperatures in a fluidized bed reactor, thereby preparing high-performance olefin polymer products.
Chinese patent CN 106928383A absorbs heat by evaporation from liquid materials entering a reaction cavity from multiple positions, and controls the ambient temperature in the reaction cavity from multiple positions, thereby being capable of carrying out polymerization reaction at multiple positions and aiming at obtaining more olefin polymers with higher branching degree. The method, however, spaces the multiple liquid inlet regions apart, creating a significant axial concentration and temperature distribution.
Chinese patent CN 103304692B sets a plurality of nozzles to be uniformly distributed along the radial direction of the fluidized bed reactor or distributed along the axial direction of the fluidized bed reactor, and matches with the temperature gradient in the fluidized bed reactor to better realize the cooling effect.
The above three patents consider that the formation of multiple temperature zones axially inside the reactor may result in intense axial mixing inside the reactor due to the distribution direction of the differentiated temperature zones being the same as the flow direction of the fluidizing gas, and the temperature difference cannot be effectively pulled apart. And reaction areas with different concentrations and temperatures are radially distributed in the reactor, and the differentiation is more remarkable and stable.
Chinese patent CN 105732849 a discloses an olefin polymerization apparatus and method, which realizes the copolymerization and homopolymerization of olefin, and the switching of copolymerization and copolymerization by introducing condensing agent and/or comonomer intermittently to the side wall of the reactor. The method has the problems that the switching time of the polymerization environment is long, and the polymerization product cannot achieve micro-level mixing.
Chinese patent CN 104558333B discloses a method for preparing olefin polymers with broad molecular weight distribution characteristics. According to the method, partial olefin monomers are condensed by only one heat exchanger, the content of the condensate is low, and a large amount of polymerization reaction heat cannot be taken away through vaporization of the condensate after the condensate is added into the reactor, so that the temperature in the reactor is difficult to keep stable only by adjusting the temperature of the liquefied gas in the reactor. And more liquid materials are generated after the circulating gas is compressed by the compressor and is subjected to heat removal by the heat exchanger, and a large amount of polymerization reaction heat can be more easily taken away after the circulating gas is added to the side wall of the reactor, so that the temperature of a bed layer of the reactor is kept stable.
In view of the above, the inventors of the present invention have conducted studies with the object of solving the problems exposed by the prior art in the related art, such as insignificant difference in axial temperature and concentration of the reactor, long switching time of polymerization environment, unstable temperature in the reactor due to insufficient heat removal of polymerization reaction, and the like, and it is desirable to provide a propylene polymerization process which solves the above problems and produces a propylene polymer having high added value of performance.
Disclosure of Invention
In view of the above disadvantages of the prior art, the present invention provides a propylene polymerization method, which utilizes the liquid material to be alternately injected into a reactor to realize the switching of the copolymerization and the homopolymerization, the copolymerization and the copolymerization of propylene, and simultaneously, because the liquid material is injected at the same axial direction and different heights of the side wall of the reactor, a reaction environment with different radial concentrations inside the reactor is created. By the method, the propylene polymer produced by polymerization reaction in different reaction concentration zones in the fluidized bed reactor has the characteristics of different molecular weights and branching degrees, the polymer chains with different lengths can realize molecular-level mixing, the propylene polymer has wider molecular weight distribution, density range and melt index range, and the mechanical property and the processability of the propylene polymer product are improved.
In order to achieve the purpose, the invention provides the following technical scheme: carrying out propylene polymerization reaction in a polymerization reactor, carrying out condensation and gas-liquid separation on circulating gas output by the polymerization reactor, respectively storing liquid materials obtained by separation in different storage tanks according to the types of polymerization monomers, then simultaneously adding or not adding the liquid materials from the different storage tanks into the polymerization reactor at the same axial direction and different heights of the side wall of the reactor for reaction, and discharging propylene polymers.
According to a preferred embodiment of the invention, the method comprises the steps of:
(1) performing propylene polymerization reaction in a polymerization reactor, compressing recycle gas led out from an outlet at the top of the reactor by a recycle gas compressor and removing heat by a recycle gas cooler to obtain a gas-liquid mixture;
(2) carrying out gas-liquid separation on the gas-liquid mixture obtained in the step (1) in gas-liquid separation equipment, and respectively storing the separated liquid materials in different storage tanks according to the types of the polymerized monomers;
(3) adding or not adding the liquid materials from the different storage tanks at the same axial direction and different heights of the side wall of the reactor at the same time or adding the liquid materials above a distribution plate in the polymerization reactor at intervals;
(4) Gas materials obtained by gas-liquid separation enter the reactor from the bottom of the reactor;
(5) in the polymerization reactor, the gaseous material and the liquid material are polymerized under the catalysis of the catalyst, and the propylene polymer is continuously or intermittently discharged from the polymerization reactor.
According to a preferred embodiment of the present invention, the efficiency of the gas-liquid separation is 30% to 100%. The gaseous feed in step (4) also contains a portion of the liquid feed that is not separated.
According to a preferred embodiment of the present invention, the polymerization reactor is preferably a fluidized bed reactor.
Simultaneously adding or not adding a liquid material at the same axial direction and different heights of the side wall of the reactor or adding a liquid material at intervals, so that the copolymerization and the homopolymerization, copolymerization and copolymerization of the propylene are switched in the fluidized bed reactor; when liquid material is sprayed into the reactor through the side wall of the reactor, a plurality of reaction areas with different hydrogen concentrations and comonomer concentrations are formed in the radial direction in the fluidized bed reactor, so that the difference of the radial component concentrations in the reactor is caused.
Specifically, in the process of the present invention, the fluidized bed reactor can be freely switched between the homopolymerization and the copolymerization. If it is necessary to cut the copolymerization reaction into homopolymerization reaction, the gas material is introduced from the lower part of the distribution plate of the reactor and contacts with the added catalyst to form solid-phase polypropylene. Unreacted recycle gas is led out from an outlet at the top of the reactor, after the recycle gas is compressed, condensed and separated in a recycle loop, the separated gas material and a part of unseparated liquid material return to the reactor from the lower part of a distribution plate of the reactor, the separated liquid material is stored in a storage tank for standby without returning to the reactor, and the comonomer contained in the liquid material is one of higher olefins such as butene, hexene, octene and the like and can be used as a copolymerization raw material. After many cycles the recycle gas is substantially free of comonomer, at which point only homopolymerization takes place in the reactor. If the homopolymerization reaction needs to be switched into the copolymerization reaction, the liquid material stored in the storage tank is introduced from a designated nozzle position above a distribution plate of the reactor, so that a plurality of reaction areas with different hydrogen concentrations and comonomer concentrations are formed in the radial direction in the fluidized bed reactor. It is to be noted that only one comonomer can be injected at a time. Unreacted circulating gas led out from an outlet at the top of the reactor is compressed, condensed and subjected to gas-liquid separation in a circulating loop, separated gas materials and a part of liquid materials return to the reactor from the lower part of a distribution plate, the separated liquid materials enter a storage tank and return to the reactor through a nozzle at a specified position on the side wall of the reactor according to the requirement of a target product, and a polymer product is intermittently or continuously taken out of the reactor through a discharge pipeline.
In the process of the present invention, the fluidized bed reactor can be freely switched between different copolymerization reactions. If it is desired to switch from one copolymerization reaction to another, the previous comonomer is no longer fed into the recycle line and the separated liquid material is stored in a storage tank without being returned to the reactor. After multiple cycles, the recycle gas does not contain the former comonomer basically, at the moment, the other comonomer is introduced into the recycle pipeline, after compression, condensation and gas-liquid separation in the recycle loop, the separated gas material and part of liquid material return to the reactor from the lower part of the distribution plate, and the separated liquid material returns to the reactor from a nozzle at a specified position on the side wall of the reactor for polymerization after passing through a storage tank and a condensate feeding pump.
According to some embodiments of the invention, the liquid feed comprises polymerized monomers, preferably comprising propylene and comonomers; and/or the comonomer is preferably at least one alpha-olefin with a carbon number of more than or equal to 4 and less than or equal to 10, selected from 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene, preferably 1-butene, 1-hexene, 1-octene.
In the process of the present invention, the unreacted recycle gas comprises polymerized monomers, a modifier and inert components; the polymerized monomers are preferably propylene and comonomers; the regulator is preferably hydrogen; the inert component is preferably nitrogen; the comonomer is preferably at least one alpha-olefin having 4 or more and 10 or less carbon atoms selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene, preferably 1-butene, 1-hexene, 1-octene.
Wherein, the content of the regulator can be 0.1-15%, so that the molecular weight and the molecular weight distribution of the propylene polymer obtained by polymerization can be adjusted according to different contents of the regulator; the content of the inert component may be 25% to 75%, whereby part of the heat generated during the polymerization can be removed and the composition of the circulating medium can be adjusted.
According to the method of the present invention, when used in homopolymerization, it is possible to produce a high-density homopolypropylene product; when used in copolymerization reactions, it can produce propylene polymer products having a higher degree of branching.
In the process of the present invention, the polymerization reaction may be carried out in the presence of a Ziegler-Natta type catalyst or a metallocene catalyst, preferably a Ziegler-Natta type catalyst. The propylene polymerization catalyst used in the present invention is typically a Ziegler-Natta type catalyst containing Mg, Ti, Al and Cl as essential components, and is characterized by stereospecificity and high yield. In addition to the solid transition metal (e.g. Ti) component, this type of catalyst comprises a cocatalyst and an external electron donor as a stereo-modifier.
Magnesium, titanium and the like may be supported on a particulate support, for example an inorganic oxide such as silica or alumina, or typically a magnesium halide may form a solid support. The solid catalyst may also be self-supported, i.e.: the catalyst is not supported on an external carrier but is prepared via an emulsion-solidification process or by a precipitation process.
The solid transition metal component typically also comprises an internal electron donor. Suitable internal electron donors are especially carboxylic esters, such as: phthalate, citraconate and succinate, oxygen-or nitrogen-containing silicon compounds can also be used, the particularly preferred compound being di-2-ethylhexyl phthalate.
The cocatalyst used in combination with the transition metal compound generally comprises an alkylaluminum compound. The aluminum alkyl compound is preferably an aluminum trialkyl, such as: trimethylaluminum, triethylaluminum, triisobutylaluminum or tri-n-octylaluminum. However, the cocatalyst may also be an alkylaluminum halide, such as: diethylaluminum chloride, dimethylaluminum chloride and ethylaluminum sesquichloride (ethylaluminum sesquichloride), and also mixtures of two or more of the abovementioned compounds. Among these, triethylaluminum is a particularly preferred alkyl aluminum compound cocatalyst. The aluminum alkyl is preferably introduced to achieve the desired aluminum to titanium ratio (aluminum/titanium), with a suitable ratio depending on the catalyst and in the range of 30 to 1000mol/mol, for example: 50 to 800 mol/mol.
Preferably, the catalyst further comprises an external electron donor. Suitable external electron donors known in the art include ethers, ketones, amines, alcohols, phenols, phosphines and silanes. The silane-type external electron donor is usually a compound containing a Si-OCOR bond, a Si-OR bond OR a Si-NR bond 2A bonded, typical organosilane compound having silicon as a central atom, and R is an alkyl, alkenyl, aryl, aralkyl or cycloalkyl group having 1 to 20 carbon atoms known in the art. The external electron donor may also be a mixture of two or more of the above compounds. Among them, the organosilane compound is a preferable external donor, and dicyclopentyldimethoxysilane and cyclohexylmethyldimethoxysilane are particularly preferable. The organosilane compound is generally introduced to maintain the molar ratio between the aluminum alkyl and the silane compound, such as: Al/Donor is from 3 to 800mol/mol or from 10 to 200 mol/mol.
Examples of suitable catalysts and components of the catalysts are shown below: WO-A-87/07620, WO-A-92/21705, WO-A-93/11165, WO-A-93/11166, WO-A-93/19100, WO-A-97/36939, WO-A-98/12234, WO-A-99/33842, WO-A-03/000756, WO-A-03/000757, WO-A-03/000754, WO-A-03/000755, WO-A-2004/029112, WO-A-92/19659, WO-A-92/19653, WO-A-92/19658, US-A-4382019, US-A-4435550, US-A-4465782, US-A-4473660, WO-A-4435550, WO-A-3978, WO-A-99/33842, WO-A-03/000756, WO-A-03/000757, and WO-A-03/000754, US-A-4560671, US-A-5539067, US-A-5618771, EP-A-45975, EP-A-45976, EP-A-45977, WO-A-95/32994, US-A-4107414, US-A-4186107, US-A-4226963, US-A-4347160, US-A-4472524, US-A-4522930, US-A-4530912, US-A-4532313, US-A-4657882, US-A-4581342, US-A-4657882.
According to a preferred embodiment of the present invention, the polymerization reactor is preferably a fluidized bed reactor having an apparent fluidizing gas velocity of 0.1 to 1.0 m/s. In the method, the polymerization reaction temperature in the reactor is 50-100 ℃, and preferably 65-90 ℃. The polymerization reaction pressure in the reactor is 1.0-4.0 MPa, preferably 1.5-3.8 MPa. The superficial fluidization gas velocity of the fluidized bed reactor is 0.1 to 1.0m/s, preferably 0.3 to 0.8 m/s. The superficial fluidization gas velocities of the fluidized bed reactor that can be enumerated for the process of the present invention include, but are not limited to: 0.3m/s, 0.35m/s, 0.41m/s, 0.4m/s, 0.5m/s, 0.55m/s, 0.61m/s, 0.68m/s, 0.7m/s, 0.75m/s and 0.8 m/s. The method of the present invention strictly controls the superficial fluidizing gas velocity of the fluidized bed reactor and aims at ensuring the good fluidizing state of the reactor and avoiding the large amount of powder material being carried out. When the apparent fluidization gas velocity is 0.3-0.8 m/s, the method can further ensure the stable operation of the fluidized bed reactor and simultaneously ensure the stable existence of a concentration difference region in the fluidized bed reactor. The reason may be that the superficial fluidization gas velocity is higher than the initial fluidization velocity of the bulk powder and lower than the entrainment velocity of most of the powder particles.
In the method of the present invention, the superficial fluidization gas velocity refers to a gas velocity calculated from an effective air cross-sectional area excluding heat exchange elements, baffles and the like and excluding the charged solids and a gas volume flow rate in an operating state.
In the method, the used circulating gas compressor is a single-section constant-speed centrifugal compressor with double mechanical seals, and the typical outlet pressure of the compressor is 3.0-4.0 MPa. The circulating gas cooler is a one-way shell-and-tube heat exchanger, circulating gas passes through a tube pass, and circulating water passes through a shell pass.
In the method, the liquid material is a liquid phase component obtained by compressing the circulating gas by a compressor, removing heat by a heat exchange device and carrying out gas-liquid separation by a separation device. During the copolymerization reaction, liquid materials flow out of different storage tanks, are pressurized by a condensate feeding pump and are simultaneously sprayed into the reactor from a plurality of nozzles in the same axial direction and different heights on the reaction side wall of the fluidized bed, so that a plurality of polymerization reaction zones with different concentrations of hydrogen and comonomers are radially formed in the fluidized bed reactor, and the heat removal capacity of the fluidized bed reactor is improved; when the copolymerization reaction is switched to the homopolymerization reaction, the liquid material obtained by separating the circulating gas led out from the top outlet of the reactor through the gas-liquid separation equipment is stored in the storage tank and is not required to be introduced into the circulating loop temporarily. The circulating gas is used for material circulation in the whole reaction system including the fluidized bed reactor, the pipeline, the heat exchange equipment, the separation equipment and the like.
In the process of the present invention, the copolymerization and homopolymerization of propylene are freely switched, and the switching frequency is at least 1 time/hour, preferably at least 2 times/hour. The frequency of switching between different copolymerizations of propylene is at least 1 time/hour, preferably at least 2 times/hour. In the present invention, the average residence time of the polypropylene in the fluidized bed is about 1 to 2 hours, and the switching frequency is at least 1 time/hour, preferably at least 2 times/hour. The switching frequency is set in consideration of feasibility, so that enough time is ensured to consume the comonomer in the previous step during switching, and polypropylene produced in different modes (homopolymerization < - > -copolymerization and copolymerization < - >) is ensured to be fully mixed.
In the process of the present invention, the alternation of homopolymerization and copolymerization of propylene is achieved by introducing and withdrawing liquid materials. The low molecular weight polypropylene product obtained by homopolymerization and the high molecular weight polypropylene product obtained by copolymerization are fully mixed in the fluidized bed reactor, so that the propylene polymer with wide molecular weight distribution can be obtained, and the mechanical property and the processing property of the polypropylene product are improved. According to different product requirements, the invention can change the properties of the target product by changing the types of the comonomers, the liquid amount of the liquid materials introduced into the reactor, the switching frequency and the like, generate the product meeting the product requirements, increase the operation flexibility and have practical significance.
According to a preferred embodiment of the invention, the liquid feeds obtained are fed simultaneously into the polymerization reactor at the same axial level and at different heights of the side wall of the reactor, through at least one nozzle arranged at the same axial level and at different heights of the side wall of the reactor. In the method, the total number of the arranged nozzles is more than or equal to 2, preferably 2-10, all the nozzles are positioned at the same axial direction and different heights of the reactor, the intervals between adjacent nozzles can be equal or unequal, but the heights are lower than the supplementary feeding ports of reactants. The nozzle installation height is 0.1-1 times of the height of the straight cylinder section of the fluidized bed reactor, and preferably 0.2-0.6 times of the height of the straight cylinder section of the fluidized bed reactor. The invention can form a plurality of polymerization reaction zones with different hydrogen concentrations and comonomer concentrations in the fluidized bed reactor in the radial direction by controlling the number and the position of the nozzles.
In the method of the present invention, the radial concentration difference in the reactor is caused by the simultaneous injection of the liquid materials at the same axial direction and different heights of the side wall of the reactor. The reaction zone near the side wall nozzle in the fluidized bed reactor has a lower hydrogen concentration than the other reaction zones connected thereto, and the reaction zone near the side wall nozzle has a higher comonomer concentration than the other reaction zones connected thereto.
Wherein the reaction area near the side wall nozzle has a lower hydrogen concentration than other reaction areas connected with the reaction area and a higher comonomer concentration than other reaction areas connected with the reaction area, and is a reaction area with a low hydrogen concentration and a high comonomer concentration; and the region far away from the side wall nozzle has higher hydrogen concentration and lower comonomer concentration than other reaction regions connected with the side wall nozzle, and is a high-hydrogen-concentration and low-comonomer-concentration reaction region. The volume of the reaction area with low hydrogen concentration and high comonomer concentration accounts for 2-80% of the volume of the fluidized bed reactor, the reaction temperature of the area is lower and is 50-80 ℃, and the comonomer/propylene concentration ratio (C)x/C3) Higher hydrogen/propylene concentration ratio (H)2/C3) The catalyst is low in cost, can effectively block hydrogen, increases the possibility of reaction of propylene and comonomer, and is beneficial to forming polypropylene products with more branched chains, low density and high molecular weight; the volume of the reaction area with high hydrogen concentration and low comonomer concentration accounts for 20-98% of the volume of the fluidized bed reactor, the reaction temperature is higher and is 60-100 ℃, and the comonomer/propylene concentration ratio (C)x/C3) Lower, hydrogen/propylene concentration (H)2/C3) Higher, is beneficial to forming polypropylene products with less branched chains, high density and low molecular weight. Thus, in a fluidized bed reactor, high and low molecular weight propylene polymer particles are obtained, which are fluidized and circulated between at least two zones to achieve good micromixing.
In the method of the present invention, the MFR of the propylene polymer product in the low hydrogen concentration, high comonomer concentration reaction zone connected to each other is 0.1 to 80g/10min, and the MFR of the propylene polymer product in the high hydrogen concentration, low comonomer concentration reaction zone is 1.0 to 100g/10 min.
In the method of the invention, the reaction zone with low hydrogen concentration and high comonomer concentration is a gas-liquid-solid fluidization zone; the reaction zone with high hydrogen concentration and low comonomer concentration is a gas-solid fluidization zone.
In the method of the present invention, the gas-solid fluidization region refers to a gas-solid two-phase region in which propylene and propylene polymer particles are continuously fluidized in the fluidized bed reactor.
In the process of the present invention, the gas-liquid-solid fluidization region refers to a gas-liquid-solid three-phase region in which propylene, comonomer and propylene polymer particles are present in the fluidized bed reactor.
In the process of the present invention, the monomer concentration in the polymerization reaction zone refers to the average concentration in the polymerization reaction zone.
In the method, the content of propylene in the liquid material is 40-99 mol%; the content of the comonomer is 1.0-60 mol%. The propylene and comonomer contents in different polymerization reaction zones in the fluidized bed reactor are different, so that the high and low molecular weight propylene polymer particles can be circulated in the fluidized bed reactor in a fluidized way to obtain a well-micromixed propylene polymer product. The liquid feed also serves to remove a substantial portion of the heat generated by the polymerization reaction throughout the polymerization reaction scheme, improving the heat removal capacity of the reactor.
In the process of the present invention, the fluidized bed reactor is preferably a gas-solid fluidized bed reactor, wherein the gas-solid fluidized bed reactor may be selected from a gas-solid bubbling fluidized bed reactor or a turbulent fluidized bed reactor.
Compared with the prior art, the propylene polymerization method has the following beneficial technical effects: the difference between the radial concentration and the temperature is more obvious and stable; the heat removal capacity of the reactor is improved; propylene polymer products with high performance added value can be produced.
According to another aspect of the present invention, there is also provided a propylene polymer prepared according to the above process. The propylene polymer product prepared by the invention has wider molecular weight distribution, density range, melt index range and the like.
Drawings
The invention will be described in more detail below on the basis of different embodiments and with reference to the drawings. Wherein:
FIG. 1A flow diagram of the propylene polymerization process of the present invention
FIG. 2 is a schematic view of a fluidized bed reactor with three nozzles disposed at different heights in the same axial direction;
FIG. 3 is a schematic view of a fluidized bed reactor with four nozzles at different heights in the same axial direction;
FIG. 4 is a sectional view in the direction C-C of the fluidized-bed reactor shown in FIG. 2 or FIG. 3;
In the drawings, like components are denoted by like reference numerals. The figures are not drawn to scale. The reference numerals are explained below:
1 distribution plate
2 a fluidized bed reactor;
3, a compression device;
4 a heat exchange device;
5 gas-liquid separation equipment;
6 a first tank for storing liquid material;
7 a first condensate feed pump for introducing liquid feed into the reactor;
8 a second tank for storing liquid material;
9 a second condensate feed pump for introducing liquid material into the reactor;
10 a plurality of liquid inlets in the side wall of the reactor;
11 a plurality of liquid inlets in the side wall of the reactor;
12 a fluid line for introducing a reaction material such as a catalyst into the reactor;
13 a gas circulation line;
14 fluid lines for introducing hydrogen, nitrogen and propylene monomers into the recycle line;
15 a fluid conduit for introducing comonomer into the recycle line;
16 a fluid conduit for introducing material separated from the separation device into the reactor;
17 a fluid conduit for introducing liquid material separated from the separation apparatus into the storage tank;
18 a fluid conduit for introducing the liquid material in the first reservoir into the reactor;
19 a fluid line for introducing the liquid material in the second reservoir into the reactor;
20 a line for withdrawing solid propylene polymer from the reactor;
a polymerization reaction area with low hydrogen concentration and high comonomer concentration;
b a polymerization reaction zone with high hydrogen concentration and low comonomer concentration.
Detailed Description
The propylene polymerization process of the present invention will be further illustrated with reference to examples. The following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents and instruments used in the examples are not indicated by the manufacturer, and are all conventional products commercially available.
Example 1
In the fluidized bed reactor 2 having nitrogen gas inside as shown in FIG. 1, first, a polymerization catalyst was continuously fed through a line 12 in an amount of 0.1kg/h, propylene was fed through a line 14, and 1-butene raw material gas was fed through a line 15 as a comonomer, and the initial olefin polymerization was started in the fluidized bed reactor to produce a small amount of polypropylene. The amount of catalyst was then increased stepwise to 5kg/h, maintaining the fluidizing gas velocity constant. As the reaction proceeds, propylene is continuously fed through the line 14 and 1-butene raw gas is continuously fed through the line 15, thereby constituting a circulating gas in the fluidized-bed reactor. The circulating gas comprises hydrogen, nitrogen, propylene and 1-butene. The components and the content of the circulating gas in the reaction system are kept unchanged in the reaction process. A pipe 13 is connected to the top expanded section of the fluidized bed reactor 2 for receiving the recycle gas from the fluidized bed reactor 2 at a pressure of 3.8MPa and a temperature of 80 ℃. When the copolymerization reaction is switched to the homopolymerization reaction, the feed of the 1-butene raw gas into the line 15 is stopped. The gas-liquid mixture passes through a gas-liquid separator 5, the separated liquid material flows into a first storage tank 6 for standby without returning to the reactor, and the separated gas material and a part of the unseparated liquid material enter the fluidized bed reactor 2 from the bottom of the reactor along with a fluid pipeline 16. After the circulation gas is circulated for many times, the circulation gas flow from the heat exchanger 4 does not contain comonomer. At the moment, gas-solid two-phase reaction is carried out in the fluidized bed reactor 2, and propylene is contacted with a continuously added catalyst to form solid polypropylene. When the homopolymerization is switched to the copolymerization, 1-butene feed gas is continuously fed into the line 15. The gas-liquid mixture exiting the heat exchanger 4 contained 22 wt% of liquid material, which was propylene and the comonomer 1-butene. After the gas-liquid mixture passes through the gas-liquid separator 5, 80 wt% of the total content of the liquid materials in the gas-liquid mixture enters the first storage tank 6 through the fluid pipeline 17, and the rest of the gas materials and the other part of the unseparated liquid materials enter the fluidized bed reactor 2 from the lower part of the distribution plate 1 along with the fluid pipeline 16. The liquid material stored in the first storage tank 6 is injected into the fluidized bed reactor 2 through the first condensate feed pump 7 and through the fluid line 18 from nozzles 2m, 5m and 8m above the distribution plate 1 (the nozzles are located on the same vertical line), thereby forming a radial difference in hydrogen concentration and comonomer concentration in the fluidized bed reactor, i.e., a reaction zone having a significant difference in hydrogen concentration and comonomer concentration is formed radially inside the reactor, as shown in fig. 2. The copolymerization and homopolymerization reactions were switched repeatedly 2 times per hour.
In this example, when the liquid material was injected from the side wall of the reactor, the volume of the low hydrogen concentration, high comonomer concentration reaction zone was 38% by volume of the fluidized bed reactor, the volume of the high hydrogen concentration, low comonomer concentration reaction zone was 62% by volume of the fluidized bed reactor, and the superficial fluidized gas velocity was 0.51 m/s.
In this example, the reaction temperature in the low hydrogen concentration, high comonomer concentration reaction zone was 65 ℃ and the 1-butene/propylene concentration ratio (C)4/C3) Higher (about 2.528), hydrogen/propylene concentration ratio (H)2/C3) Lower (about 0.0151) and in which more branched, low density, high molecular weight propylene polymers are formed. The reaction temperature in the reaction zone with high hydrogen concentration and low comonomer concentration is 79 ℃, and the concentration ratio of 1-butylene/propylene (C)4/C3) Lower (about 0.0309), hydrogen/propylene concentration (H)2/C3) Higher (about 0.183) where less branched, high density, low molecular weight propylene polymers are formed.
This example uses magnesium chloride-loaded TiCl3As catalyst, triethyl aluminum is used as cocatalyst, dicyclopentyl dimethoxy silane is used as external electron donor.
The contents of the components of the recycle gas after the homopolymerization cut-in copolymerization in this example are shown in Table 1 below.
TABLE 1
The characterization results of the properties and structure of the polybutylene terephthalate polymer a prepared in this example are shown in table 6 below.
Example 2
In the fluidized bed reactor 2 having nitrogen gas inside as shown in FIG. 1, first, a polymerization catalyst was continuously fed through a line 12 in an amount of 0.1kg/h, propylene was fed through a line 14, and 1-hexene raw material gas was fed through a line 15 as a comonomer, and the initial olefin polymerization was started in the fluidized bed reactor to produce a small amount of polypropylene. The amount of catalyst was then increased stepwise to 5kg/h, maintaining the fluidizing gas velocity constant. As the reaction proceeded, propylene was continuously fed through the line 14 and 1-hexene raw material gas was continuously fed through the line 15, thereby constituting a recycle gas in the fluidized-bed reactor. The circulating gas comprises hydrogen, nitrogen, propylene and 1-hexene. The components and the content of the circulating gas in the reaction system are kept unchanged in the reaction process. A conduit 13 is connected to the top expanded section of the fluidized bed reactor 2 for receiving the recycle gas from the fluidized bed reactor 2 at a pressure of 3.7MPa and a temperature of 81 ℃. When the copolymerization reaction is switched to the homopolymerization reaction, the supply of the 1-hexene raw material gas to the line 15 is stopped. The gas-liquid mixture passes through the gas-liquid separator 5, the separated liquid material flows into the second storage tank 8 for standby without returning to the reactor, and the separated gas material and a part of the unseparated liquid material enter the fluidized bed reactor 2 from the bottom of the reactor along with the fluid pipeline 16. After the circulation gas is circulated for many times, the circulation gas flow from the heat exchanger 4 does not contain comonomer. At the moment, gas-solid two-phase reaction is carried out in the fluidized bed reactor 2, and propylene is contacted with a continuously added catalyst to form solid polypropylene. When the homopolymerization is switched to the copolymerization, 1-hexene gas is continuously supplied to the line 15. The gas-liquid mixture from the heat exchanger 4 contained 20 wt% of liquid material, which was propylene and comonomer 1-hexene. After the gas-liquid mixture passes through the gas-liquid separator 5, 80 wt% of the total content of the liquid materials in the gas-liquid mixture enters the second storage tank 8 through the fluid pipeline 17, and the rest of the gas materials and the other part of the unseparated liquid materials enter the fluidized bed reactor 2 from the lower part of the distribution plate 1 along with the fluid pipeline 16. The liquid material stored in the second storage tank 8 is injected into the fluidized bed reactor 2 through the second condensate feed pump 9 and through the fluid line 19 from nozzles 2m, 5m and 8m above the distribution plate 1 (the nozzles are located on the same vertical line), thereby forming a radial difference in hydrogen concentration and comonomer concentration in the fluidized bed reactor, i.e., a reaction zone with a significant difference in hydrogen concentration and comonomer concentration is formed radially inside the reactor, as shown in fig. 2. The copolymerization and homopolymerization reactions were switched repeatedly 2 times per hour.
In this example, when the liquid material was injected from the side wall of the reactor, the volume of the low hydrogen concentration, high comonomer concentration reaction zone was 35% by volume of the fluidized bed reactor, the volume of the high hydrogen concentration, low comonomer concentration reaction zone was 65% by volume of the fluidized bed reactor, and the superficial fluidized gas velocity was 0.61 m/s.
In this example, the reaction temperature in the low hydrogen concentration, high comonomer concentration reaction zone was 66 ℃ and the 1-hexene/propylene concentration ratio (C)6/C3) Higher (about 2.628), hydrogen/propylene concentration ratio (H)2/C3) Lower (about 0.0128), in which more branched, low density, high molecular weight propylene polymers are formed. The reaction temperature in the reaction zone with high hydrogen concentration and low comonomer concentration was 79 ℃ and the 1-hexene/propylene concentration ratio (C)6/C3) Lower (about 0.0329), hydrogen/propylene concentration (H)2/C3) Higher (about 0.177) where less branched, high density, low molecular weight propylene polymers are formed.
This example uses magnesium chloride-loaded TiCl3As catalyst, triethyl aluminum is used as cocatalyst, dicyclopentyl dimethoxy silane is used as external electron donor.
The contents of the components of the recycle gas after the homopolymerization cut-in copolymerization in this example are shown in Table 2 below.
TABLE 2
The characterization results of the properties and structure of the dihexyl polymer B prepared in this example are shown in Table 6 below.
Example 3
In the fluidized bed reactor 2 having nitrogen gas inside as shown in FIG. 1, first, a polymerization catalyst was continuously fed through a line 12 in an amount of 0.1kg/h, propylene was fed through a line 14, and 1-butene raw material gas was fed through a line 15 as a comonomer, and the initial olefin polymerization was started in the fluidized bed reactor to produce a small amount of polypropylene. The amount of catalyst was then increased stepwise to 5kg/h, maintaining the fluidizing gas velocity constant. As the reaction proceeds, propylene is continuously fed through the line 14 and 1-butene raw gas is continuously fed through the line 15, thereby constituting a circulating gas in the fluidized-bed reactor. The circulating gas comprises hydrogen, nitrogen, propylene and 1-butene. The components and the content of the circulating gas in the reaction system are kept unchanged in the reaction process. A line 13 is connected to the top expanded section of the fluidized bed reactor 2 for receiving the recycle gas from the fluidized bed reactor 2 at a pressure of 3.7MPa and a temperature of 79 ℃. When the copolymerization reaction is switched to the homopolymerization reaction, the feed of the 1-butene raw gas into the line 15 is stopped. The gas-liquid mixture passes through a gas-liquid separator 5, the separated liquid material flows into a first storage tank 6 for standby without returning to the reactor, and the separated gas material and a part of the unseparated liquid material enter the fluidized bed reactor 2 from the bottom of the reactor along with a fluid pipeline 16. After the circulation gas is circulated for many times, the circulation gas flow from the heat exchanger 4 does not contain comonomer. At the moment, gas-solid two-phase reaction is carried out in the fluidized bed reactor 2, and propylene is contacted with a continuously added catalyst to form solid polypropylene. When the homopolymerization is switched to the copolymerization, 1-butene feed gas is continuously fed into the line 15. The gas-liquid mixture coming out of the heat exchanger 4 contains 20 wt% of liquid materials, wherein the liquid materials are propylene and comonomer 1-butene. After the gas-liquid mixture passes through the gas-liquid separator 5, 80 wt% of the total content of the liquid materials in the gas-liquid mixture enters the first storage tank 6 through the fluid pipeline 17, and the rest of the gas materials and the other part of the unseparated liquid materials enter the fluidized bed reactor 2 from the lower part of the distribution plate 1 along with the fluid pipeline 16. The liquid material stored in the first storage tank 6 is injected into the fluidized bed reactor 2 through the first condensate feed pump 7 and through the fluid line 18 from nozzles 2m, 5m, 8m and 10m above the distribution plate 1 (the nozzles are located on the same vertical line), thereby forming a radial difference in hydrogen concentration and comonomer concentration in the fluidized bed reactor, i.e., a reaction zone with a significant difference in hydrogen concentration and comonomer concentration is formed radially inside the reactor, as shown in fig. 3. The copolymerization and homopolymerization reactions were switched repeatedly 2 times per hour.
In this example, when the liquid material was injected from the side wall of the reactor, the volume of the low hydrogen concentration, high comonomer concentration reaction zone was 49% by volume of the fluidized bed reactor, the volume of the high hydrogen concentration, low comonomer concentration reaction zone was 51% by volume of the fluidized bed reactor, and the superficial fluidized gas velocity was 0.62 m/s.
In this example, the reaction temperature in the low hydrogen concentration, high comonomer concentration reaction zone was 64 ℃ and the 1-butene/propylene concentration ratio (C)4/C3) Higher (about 2.705), hydrogen/propylene concentration ratio (H)2/C3) Lower (about 0.0128), in which more branched, low density, high molecular weight propylene polymers are formed. The reaction temperature in the reaction zone with high hydrogen concentration and low comonomer concentration is 81 ℃, and the concentration ratio of 1-butylene/propylene (C)4/C3) Lower (about 0.0315), hydrogen/propylene concentration (H)2/C3) Higher (about 0.188) where less branched, high density, low molecular weight propylene polymers are formed.
This example uses magnesium chloride-loaded TiCl3As catalyst, triethyl aluminum is used as cocatalyst, dicyclopentyl dimethoxy silane is used as external electron donor.
The contents of the components of the recycle gas after the homopolymerization cut-in copolymerization in this example are shown in Table 3 below.
TABLE 3
The characterization results of the properties and structure of the polybutylene terephthalate polymer C prepared in this example are shown in table 6 below.
Comparative example 1
In the fluidized bed reactor 2 having nitrogen gas inside as shown in FIG. 1, first, a polymerization catalyst was continuously fed through a line 12 in an amount of 0.1kg/h, propylene was fed through a line 14, and 1-butene raw material gas was fed through a line 15 as a comonomer, and the initial olefin polymerization was started in the fluidized bed reactor to produce a small amount of polypropylene. The amount of catalyst was then increased stepwise to 5kg/h, maintaining the fluidizing gas velocity constant. As the reaction proceeds, propylene is continuously fed through the line 14 and 1-butene raw gas is continuously fed through the line 15, thereby constituting a circulating gas in the fluidized-bed reactor. The circulating gas comprises hydrogen, nitrogen, propylene and 1-butene. The components and the content of the circulating gas in the reaction system are kept unchanged in the reaction process. A line 13 is connected to the top expanded section of the fluidized bed reactor 2 for receiving the recycle gas from the fluidized bed reactor 2 at a pressure of 3.7MPa and a temperature of 79 ℃. The circulating gas passes through a compressor 3 and a heat exchanger 4, and then enters the fluidized bed reactor 2 along with a fluid pipeline 16 below the distribution plate 1, so that the copolymerization reaction of the propylene and the butylene is carried out in the reactor.
This example uses magnesium chloride-loaded TiCl3As catalyst, triethyl aluminum is used as cocatalyst, dicyclopentyl dimethoxy silane is used as external electron donor.
The contents of the components of the recycle gas in this example are shown in Table 4 below.
TABLE 4
The characterization results of the properties and structure of the polybutylene terephthalate polymer D prepared in this example are shown in table 6 below.
Comparative example 2
This comparative example prepared a propylene polymer using propylene as the monomer polymer and 1-butene as the comonomer, using the method disclosed in example 3 of CN 105732849 a.
The contents of the components of the recycle gas after the homopolymerization cut-in copolymerization in this example are shown in Table 5 below.
TABLE 5
The characterization results of the properties and structure of the polybutylene terephthalate polymer E prepared in this example are shown in table 6 below.
TABLE 6
As can be seen from the characterization results of the propylene polymers prepared in examples 1-3 and comparative examples 1 and 2, the propylene polymers A, C and B prepared in examples 1-3 have larger molecular weight distribution indexes (M) than the propylene polymer D, Ew/Mn) This shows that the propylene polymers obtained by the process of the present invention have a broad molecular weight distribution. In addition, the copolymer A, B, C prepared using the present invention was lower in density than copolymer D, E, indicating that a lower density propylene polymer could be obtained using the process of the present invention. In addition, the process of the present invention, because it is operated in the condensing mode, improves the heat transfer efficiency and has a greater space-time yield than comparative examples 1 and 2, greatly increasing the production of propylene polymer per unit volume of bed per unit time. The different numbers of nozzles are used in the example 1 and the example 3, and the number of nozzles used in the example 3 is larger than that of the nozzles in the example 1, compared with the discovery that the inner radial direction of the reactor in the example 3 can generate more obvious concentration distribution, and the volume of the reaction zone with low hydrogen concentration and high comonomer concentration occupies the volume of the total reactor, and the generated copolymer C has a larger molecular weight distribution than the copolymer A.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.
Claims (12)
1. A propylene polymerization process, the process comprising: carrying out propylene polymerization reaction in a polymerization reactor, carrying out condensation and gas-liquid separation on circulating gas output by the polymerization reactor, respectively storing liquid materials obtained by separation in different storage tanks according to the types of polymerization monomers, then simultaneously adding or not adding the liquid materials from the different storage tanks into the polymerization reactor at the same axial direction and different heights of the side wall of the reactor for reaction, and discharging propylene polymers.
2. Method according to claim 1, characterized in that it comprises the following steps:
(1) performing propylene polymerization reaction in a polymerization reactor, compressing recycle gas led out from an outlet at the top of the reactor by a recycle gas compressor and removing heat by a recycle gas cooler to obtain a gas-liquid mixture;
(2) carrying out gas-liquid separation on the gas-liquid mixture obtained in the step (1) in gas-liquid separation equipment, and respectively storing the separated liquid materials in different storage tanks according to the types of the polymerized monomers;
(3) adding or not adding the liquid materials from the different storage tanks at the same axial direction and different heights of the side wall of the reactor at the same time or adding the liquid materials above a distribution plate in the polymerization reactor at intervals;
(4) gas materials obtained by gas-liquid separation enter the reactor from the bottom of the reactor;
(5) in the polymerization reactor, the gaseous material and the liquid material are polymerized under the catalysis of the catalyst, and the propylene polymer is continuously or intermittently discharged from the polymerization reactor.
3. The process according to claim 1 or 2, characterized in that the recycle gas comprises propylene, comonomers, regulators and inert components; the regulator is preferably hydrogen; the inert component is preferably nitrogen; and/or, the liquid feed comprises propylene and a comonomer; and/or the comonomer is preferably at least one alpha-olefin with a carbon number of more than or equal to 4 and less than or equal to 10, the alpha-olefin is selected from 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene, and preferably 1-butene, 1-hexene, 1-octene.
4. The process according to any one of claims 1 to 3, characterized in that the polymerization reactor is preferably a fluidized bed reactor having a superficial fluidization gas velocity of 0.1 to 1.0 m/s; the polymerization reaction temperature in the fluidized bed reactor is 50-100 ℃, and preferably 65-90 ℃; the polymerization reaction pressure in the fluidized bed reactor is 1.0-4.0 MPa, preferably 1.5-3.8 MPa.
5. Process according to any one of claims 1 to 4, characterized in that the liquid feed is fed simultaneously into the polymerization reactor at the same axial and different heights of the reactor side wall through at least one nozzle arranged at the same axial and different heights of the reactor side wall; the number of the nozzles is preferably 2-10, and the installation height of the nozzles is 0.1-1 times of the height of the polymerization reactor straight cylinder section, and preferably the installation height of the nozzles is 0.2-0.6 times of the height of the polymerization reactor straight cylinder section.
6. Process according to any one of claims 1 to 5, characterized in that the liquid feeds are fed simultaneously at the same axial direction and at different heights in the reactor side wall, and that, when the liquid feeds are fed into the reactor through the reactor side wall, a plurality of reaction zones with different hydrogen concentrations and comonomer concentrations are formed radially inside the polymerization reactor, resulting in a difference in the concentration of the radial components inside the reactor.
7. The process of any one of claims 1 to 6 wherein the reaction zone adjacent the sidewall nozzle has a lower hydrogen concentration and a higher comonomer concentration than the other reaction zones associated therewith and is a low hydrogen concentration, high comonomer concentration reaction zone; and the region far away from the side wall nozzle has higher hydrogen concentration and lower comonomer concentration than other reaction regions connected with the side wall nozzle, and is a high-hydrogen-concentration and low-comonomer-concentration reaction region.
8. The process of any one of claims 1 to 7, wherein the temperature of the low hydrogen concentration, high comonomer concentration zone is from 50 to 80 ℃ and the temperature of the high hydrogen concentration, low comonomer concentration zone is from 60 to 100 ℃.
9. The process of any of claims 1-8 wherein the volume of the low hydrogen concentration, high comonomer concentration reaction zone comprises from 2% to 80% of the volume of the polymerization reactor and the volume of the high hydrogen concentration, low comonomer concentration reaction zone comprises from 20% to 98% of the volume of the polymerization reactor.
10. The process of any one of claims 1-9, wherein the low hydrogen concentration, high comonomer concentration reaction zone is a gas-liquid-solid fluidization zone and the high hydrogen concentration, low comonomer concentration reaction zone is a gas-solid fluidization zone.
11. The process according to any one of claims 1 to 10, wherein the switching between copolymerization and homopolymerization, copolymerization and copolymerization of propylene is effected in a polymerization reactor with or without simultaneous addition of one of the comonomer liquid feeds to the polymerization reactor, or with the addition of one of the comonomer liquid feeds at intervals; the frequency of switching between copolymerization and homopolymerization of propylene is at least 1 time/hour, preferably at least 2 times/hour; and/or the frequency of switching between different copolymerizations of said propylene is at least 1 time/hour, preferably at least 2 times/hour.
12. A propylene polymer prepared according to the process of any one of claims 1-11.
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| CN113583167A (en) * | 2021-08-27 | 2021-11-02 | 云南云天化石化有限公司 | Device and method for producing propylene-butylene random copolymerization polypropylene by gas phase process |
| CN115232239A (en) * | 2021-04-22 | 2022-10-25 | 中国石油化工股份有限公司 | Ethylene-butene-octene terpolymer and preparation method and system thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107405593A (en) * | 2014-12-09 | 2017-11-28 | 中国石油化工股份有限公司 | A kind of olefinic polymerization device and olefine polymerizing process |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107405593A (en) * | 2014-12-09 | 2017-11-28 | 中国石油化工股份有限公司 | A kind of olefinic polymerization device and olefine polymerizing process |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115232239A (en) * | 2021-04-22 | 2022-10-25 | 中国石油化工股份有限公司 | Ethylene-butene-octene terpolymer and preparation method and system thereof |
| CN115232239B (en) * | 2021-04-22 | 2024-01-19 | 中国石油化工股份有限公司 | Ethylene-butene-octene terpolymer and preparation method and system thereof |
| CN113583167A (en) * | 2021-08-27 | 2021-11-02 | 云南云天化石化有限公司 | Device and method for producing propylene-butylene random copolymerization polypropylene by gas phase process |
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