Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A process for producing high density polyethylene suitable for blow molding and having high environmental stress cracking resistance and rigidity copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 10 carbon atoms, in the presence of a chromium-based catalyst, having an alumina-containing support, and an organoboron compound, wherein the atomic ratio of boron in the organoboron compound to the chromium in the chromium-based catalyst is from around 0.2 to around 0.4.

Abstract: A process for producing a chromium-based catalyst for the production of polyethylene, the process comprising providing a silica support having a surface area of at least 380 m2/g and a pore volume of at least 1.5 ml/g; impregnating the silica support with a liquid including a source of aluminum ions and a source of phosphate ions; neutralizing the resultant impregnated support with a neutralizing agent to provide a pH greater than 7 for the resultant neutralized support whereby aluminum phosphate forms in pores of the silica support; and, at any stage in the method, impregnating the silica support with a chromium component.

Abstract: A process for producing medium density polyethylene by copolymerizing ethylene and an alpha-olefinic comonomer comprising from 3 to 10 carbon atoms in the presence of a chromium-based catalyst having a support comprising silica and titania, the catalyst being fluorinated and having been chemically reduced by carbon monoxide, and in the presence of a co-catalyst selected from at least one of an aluminum alkyl and a zinc alkyl to produce a polyethylene copolymer having a density of from 0.930 to 0.945 g/cc and a dispersion index (D) of from 9 to 13.

Abstract: A process for producing a chromium-based catalyst for the production of polyethylene, the process comprising the steps of providing a catalyst support selected from silica, silica-titania and silica-zirconia; reacting the support with one of an aluminium alkyl compound or a chromium salt compound selected from at least one of chromium (III) acetylacetonate, chromium (III) acetate, chromium (III) oxalate and chromium (III) stearate; and thereafter reacting the support with the other of the aluminium alkyl compound or the chromium salt to produce a chromium-impregnated catalyst having a silica-alumina support, the catalyst composition comprising from 0.4 to 1.5 wt % chromium, based on the weight of the chromium-based catalyst and the alumina in the silica-containing support comprising from 0.5 to 4 wt % aluminium in the chromium-based catalyst.

Abstract: Medium-chain olefins containing as impurities 2-alkyl substituted isomers having a close boiling point are purified by (i) passing over a solid acid catalyst under mild conditions to selectively double-bond isomerise said impurities, and (ii) separating said isomerised olefins by distillation.

Abstract: Olefin polymerization is conducted with a Ziegler-Natta catalyst in which unreacted monomer is recycled to the reactor. The recycle line contains a supported nickel or nickel oxide to purify the unreacted monomer before its return to the reactor, and results in improved catalyst activity and more control over physical properties of the product.

Abstract: The present invention relates to a process for removing arsine from a light olefin to containing hydrocarbon feedstock, said process comprising the steps of (a) passing said feedstock over an absorbent material comprising nickel deposited on a support material wherein nickel is present as both nickel oxide and metallic nickel; and (b) recovering a stream having a substantially reduced arsine content.