摘要:
The present invention concerns a catalyst for the production of high density polyethylene, by homopolymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer comprising 3 to 10 carbon atoms, prepared by the steps of: a) selecting a silica support with a specific surface area larger than 300 m2/g; b) treating the silica support with a titanium compound, in order to introduce titanium into the support, or with an aluminium compound, in order to introduce aluminum into the support; c) either treating the titanated silica support with an aluminum compound, in order to introduce aluminum into the titanated silica support, or treating the aluminated silica support with a titanium compound, in order to introduce titanium into the aluminated silica support; d) depositing a chromium compound on the titanated and aluminated silica support to form a catalyst; e) activating the catalyst of step d) under air in a fluidised bed at a temperature of from 600 to 800° C.
摘要:
The present invention relates to a process for preparing silica-alumina carriers preferably under the form of extrudates. Further, the present invention also provides hydrogenation catalysts prepared thereof. These catalysts are used in an improved process for the reduction of the aromatic hydrocarbons content present in hydrocarbon streams.
摘要:
A method for the copolymerization of ethylene and a C3+ olefin in a loop reactor and polymers formed therefrom are described herein. The method generally includes introducing an ethylene monomer, a C3+ olefin and a diluent carrier liquid into a loop reactor. A catalyst system can be supplied to said loop reactor. The diluent liquid, ethylene monomer, and C3+ olefin can be circulated through said loop reactor, while copolymerizing said ethylene and C3+ olefin in the presence of said catalyst system to produce a slurry. The slurry can be diverted into a settling leg, and sequentially discharged therefrom and withdrawn from said loop reactor. An ethylene monomer co-feed can be introduced into said loop reactor at spaced locations downstream of the ethylene and diluent. The ethylene co-feed can be introduced in an amount effective to reduce the variation in the ratio of ethylene and C3+ olefin.
摘要:
The present invention discloses the use of a chromium-based catalyst system in two serially connected loop reactors for copolymerising ethylene and a comonomer, at reduced productivity, the final polyethylene having a reduced amount of gel.
摘要:
The present invention concerns a catalyst for the production of high density polyethylene, by homopolymerising ethylene or copolymerising ethylene and an alpha-olefinic comonomer comprising 3 to 10 carbon atoms, prepared by the steps of: a) selecting a silica support with a specific surface area larger than 300 m2/g; b) treating the silica support with a titanium compound, in order to introduce titanium into the support, or with an aluminium compound, in order to introduce aluminium into the support; c) either treating the titanated silica support with an aluminum compound, in order to introduce aluminum into the titanated silica support, or treating the aluminated silica support with a titanium compound, in order to introduce titanium into the aluminated silica support; d) depositing a chromium compound on the titanated and aluminated silica support to form a catalyst; e) activating the catalyst of step d) under air in a fluidised bed at a temperature of from 600 to 800° C.
摘要:
The present invention relates to an apparatus and process for polymerizing olefins. One embodiment comprises polymerizing at least one monomer in a first loop reactor in the presence of a catalyst to produce a first polyolefin fraction. A portion of the first polyolefin fraction is transferred to a second loop reactor, connected in series with the first loop reactor. The process further comprises polymerizing in the second loop reactor at least one monomer in the presence of a catalyst to produce a second polyolefin fraction in addition to the first polyolefin fraction. The combination of the first and second polyolefin fractions can produce a polymer resin fluff having bimodal molecular weight distribution.
摘要:
A method for the copolymerization of ethylene and a C3+ olefin copolymer in a loop reactor system and polymers formed therefrom are described herein. The method generally includes introducing an ethylene monomer, a C3+ alpha olefin comonomer and a diluent carrier liquid into a reactor system comprising at least one loop reactor; supplying at least one polymerization catalyst system to said reactor system; circulating said diluent liquid, ethylene monomer, and alpha olefin copolymer through said loop reactor while copolymerizing said ethylene and said alpha olefin monomer in the presence of said catalyst system to produce a slurry of polymer fluff particles in said diluent carrier liquid; diverting the flow of said slurry through said loop reactor into at least one settling leg connected to the loop reactor and sequentially discharging the settled polymer slurry from said at least one settling leg to withdraw said polymer slurry from said reactor system; and introducing an ethylene monomer co-feed into said loop reactor at least two spaced locations downstream of the point of introduction of ethylene comonomer and diluent in subparagraph a), said ethylene co-feed being introduced in an amount effective to reduce the variation in the ratio of ethylene monomer and comonomer within said loop reactor.
摘要:
The present invention discloses the use of a chromium-based catalyst system in two serially connected loop reactors for copolymerising ethylene and a comonomer, at reduced productivity, the final polyethylene having a reduced amount of gel.
摘要:
An olefin polymerisation process carried out in the presence of an anti-fouling agent and a chromium-type catalyst or Ziegler Natta catalyst; characterised in that the anti-fouling agent comprises an anti-fouling polymer having an average molecular weight (Mw) of greater than 1000 daltons and containing: (1) one or more blocks —(CH2—CH2—O)k— where each k is in the range from 1 to 50; and (2) one or more blocks —(CH2—CH(R)—(O)n where R comprises an alkyl group having from 1 to 6 carbon atoms and each n is in the range from 1 to 50, and terminated by a R′ and a R″ end groups, wherein R′ is OH or an alkoxy having from 1 to 6 carbon atoms and R″ is H or an alkyl having from 1 to 6 carbon atoms.
摘要:
A process for producing a polyethylene resin having a monomodal molecular weight distribution in a single polymerisation reactor using a chromium-based catalyst system, by copolymerising ethylene and an alpha-olefinic-comonomer having from 3 to 8 carbon atoms, the polyethylene resin comprising a blend of a higher molecular weight fraction polymerised by a first chromium-based catalyst of the system and a lower molecular weight fraction polymerised by a second chromium-based catalyst of the system, wherein the comonomer incorporation in the higher molecular weight fraction is greater than the comonomer incorporation in the lower molecular weight fraction is greater than the comonomer incorporation in the lower molecular weight fraction whereby the higher and lower molecular weight fractions differ in density by from 0.01 to 0.03 g/cc.