Abstract: A multimodal linear low density polyethylene polymer having a final density of 900 to 940 kg/m3, and containing at least one ?-olefin comonomer in addition to ethylene comprising: (A) 30 to 60 wt % of a lower molecular weight component being an ethylene homopolymer or a copolymer of ethylene and at least one ?-olefin; and (B) 70 to 40 wt % of a higher molecular weight component being a copolymer of ethylene and at least one ?-olefin, said ?-olefin being the same or different from any ?-olefin used in component (A) but with the proviso that both components (A) and (B) are not polymers of ethylene and butane alone; wherein the multimodal LLDPE has a dart drop of at least 700 g; and wherein components (A) and (B) are obtainable using a Ziegler-Natta catalyst.

Abstract: A process for preparing a supported catalyst system comprising the following steps: a. titanating a silica-containing catalyst support having a specific surface area of from 150 m2/g to 800 m2/g, preferably 280 to 600 m2/g, with at least one vapourised titanium compound of the general formula selected from RnTi(OR?)m and (RO)nTi(OR?)m, wherein R and R? are the same or different and are selected from hydrocarbyl groups containing from 1 to 12 carbon and halogens, and wherein n is 0 to 4, m is 0 to 4 and m+n equals 4, to form a titanated silica-containing catalyst support having at least 0.1 wt % of Ti based on the weight of the titanated silica-containing catalyst support, b. treating the support with a catalyst activating agent, preferably an alumoxane. c. treating the titanated support with at least one metallocene during or after step (b).

Abstract: The present invention discloses a slurry loop reactor comprising at least two loop reactors connected in series and wherein the line connecting the two loops is subject to a dynamic pressure difference.

Abstract: Methods for removing polymer skins or build-up from reactor walls in polymerization reactor systems containing a loop slurry reactor are disclosed. Such methods can employ removing some or all of the comonomer from the reactor system in combination with increasing the polymerization temperature of the loop slurry reactor.

Abstract: The present invention relates to a method for consecutively producing at least two different polyethylene resins in one slurry loop reactor, comprising producing a first polyethylene resin in the presence of a Ziegler-Natta and/or a Chromium catalyst, and consecutively producing a second polyethylene resin in the presence of a metallocene catalyst, characterized in that the ratio of the melt flow index of the first produced polyethylene resin to the melt flow index of the second produced polyethylene resin is at least 0.3.

Abstract: The present invention relates to a process of preparing a polyolefin in a loop reactor by introducing anti-fouling agent in by-pass pipes. Also, the invention relates to the use of anti-fouling agent to prevent blockage by feeding the anti-fouling agent into the by-pass pipes of the loop reactor.

Abstract: The invention relates to high pressure tubular reactor olefin polymerization plants having improved specific energy consumption. The plants may be newly constructed or made by de-bottlenecking an existing plant. The tube of the tubular reactor may have improved arrangements for cooling to increase conversion and optimized polymer-recycle gas separation arrangements using a jet pump for recycling unreacted monomer while permitting haze to be maintained. The improved cooling arrangements include a reduced pressure cooling zone forming the tail end of the tube and/or a shortened heating zone for the front feed and allowing more monomer to be fed as a side feed.

Abstract: The invention relates to a process for the preparation of a particulate bimodal polyethylene product having a median particle diameter of less than 300 ?m in a serially connected double loop reactor, wherein said polymerization catalyst applied in the polymerization process comprises a particulate metallocene-alumoxane catalyst immobilized on a porous silica support, wherein said polymerization catalyst has a median particle diameter of less than 50 ?m; and whereby the ratio of the median particle diameter of the obtained bimodal polyethylene product to the median particle diameter of the applied polymerization catalyst is less than 30.

Abstract: The present inventions relates to a process for producing polyethylene compositions comprising polymerizing polyethylene resins in a cascaded multi-stage reaction in which the reaction steps are performed in at least two slurry phase reactors (A) and (B) and at least one gas phase reactor (C) which are arranged in series in any order wherein in reactor (A) a low molecular weight ethylene homo- or copolymer fraction having a MFR2 of 100 to 2000 g/10 min, in reactor (B) a low molecular weight ethylene homo- or copolymer fraction having an MFR2 of 100 to 2000 g/10 min, and in reactor (C) a high molecular weight ethylene copolymer fraction are polymerized, and further comprising a compounding step after polymerization, wherein the final polyethylene composition has a MFR21 of 3 to 50 g/10 min, the melt flow rates being determined according to ISO 1133.

Abstract: The present invention relates to a process of preparing a polyethylene in a loop reactor in the presence of antifouling agent comprising the steps of: a) feeding into said loop reactor diluent, monomers, optionally hydrogen, and optionally one or more co-monomers to produce a liquid phase; b) introducing antifouling agent into said loop reactor, c) introducing a catalyst into the liquid phase to produce a slurry; and d) polymerizing the monomers and optional co-monomers to form the polyethylene, characterized in that the time difference between introduction of the antifouling agent and introduction of the catalyst is at most 3 hours.

Abstract: The present invention relates to a process of preparing a polyolefin in a loop reactor by introducing anti-fouling agent through a sleeve provided around at least part of the shaft of the pump. Also, the invention relates to the use of anti-fouling agent to prevent or reduce fouling by feeding the anti-fouling agent against the impeller of the pump upon introduction to the loop reactor.

Abstract: The present invention relates the use of a pump in a loop reactor for the production of polyethylene, as well as a reactor comprising such pump and methods for producing polyolefin by means of such reactor. The pump according to the invention is characterized in that it is an axial flow impeller circulation pump, wherein the impeller comprises 6 blades and wherein the pump is fixed on a spring supported frame. Use of the pump according to the present invention allows for preparation of homogeneous polyethylene products that meet high quality standards from the complicated ethylene polymerization mixtures while at the same time being produced with low energy consumption.

Abstract: The present invention relates to a process for producing steam using heat recovered from a polymerization reaction. In particular, the present invention relates to a process for producing steam using heat recovered from a polymerization reaction for producing polyolefin, comprising the steps of: thermally contacting said polymerization reaction with a cooling fluid such that the cooling fluid removes heat from said reaction, thermally contacting at least part of said cooling fluid with at least one absorption cycle thereby transferring heat from the cooling fluid to said absorption cycle, using said absorption cycle to produce steam from a condensate, wherein the cooling fluid is used as a hot source for heating at least one evaporator and at least one generator comprised in said at least one absorption cycle. The present invention also relates to a process for cooling a polymerization reaction using a process as described herein. Said invention also relates to a polyolefin producing unit.

Abstract: An olefin polymerization process and apparatus wherein a fluid slurry comprising monomer, diluent and catalyst is circulated in a continuous loop reactor by two or more pumps. The process and apparatus allow operating the reaction at significantly higher solids content in the circulating fluid slurry. In a preferred embodiment, the fluid slurry is circulated by two impellers arranged so that the downstream impeller benefits from the rotational energy imparted by the upstream impeller. An olefin polymerization process operating at higher reactor solids by virtue of more aggressive circulation has improved efficiencies, particularly in larger-volume reactors.

Abstract: The present invention relates to a process for improving the devolatilization of polymer slurry produced in an olefin polymerization reactor. The process is characterized in that it involves an adjustment of the temperature of the interior surface of the flash line for periodically transferring polymer slurry from the polymerization reactor to a downstream processing unit. In particular, in accordance with the present process, the temperature of the interior surface of the flash line is adjusted to a temperature which is equal to or higher than the softening temperature of the polymer passing through said flash line whereby said temperature is higher in a first half of the length of the flash line than in the remaining length of the flash line.

Abstract: A process for producing water-absorbing polymer particles by polymerizing droplets of a monomer solution in a gas phase surrounding the droplets, wherein the particle surface is coated at least partly with at least one polymer and/or wax.

Abstract: Disclosed is an ethylene-based polymer with a density from about 0.90 to about 0.94 in grams per cubic centimeter, with a molecular weight distribution (Mw/Mn) from about 2 to about 30, a melt index (I2) from about 0.1 to about 50 grams per 10 minutes, and further comprising sulfur from about 5 to about 4000 parts per million. The amount of sulfur is also determined based upon the total weight of the ethylene-based polymer. Also disclosed is process for making an ethylene-based polymer which includes the steps of splitting a process fluid for delivery into a tubular reactor; feeding an upstream process feed stream into a first reaction zone and at least one downstream process feed stream into at least one other reaction zone, where the process fluid has an average velocity of at least 10 meters per second; and initiating a free-radical polymerization reaction.

Abstract: Processes for producing high pressure polyethylene and processes for increasing the crosslinkability of high pressure polyethylene are disclosed. The processes comprise controlling particular reaction parameters that have been found to promote crosslinkability in the resulting high pressure polyethylene. High pressure polyethylenes having improved crosslinkability are also disclosed.

Abstract: An emulsion polymerization process using a redox initiator comprising a reductant and an oxidant, wherein monomers are mixed into a carrier liquid, e.g. water, to make a pre-emulsion, which is then supplied to a reactor comprising one or more circulation loops, an outlet, and a circulation pump for circulating a reactor charge within the circulation loop, characterized in that the reductant is added to the pre-emulsion before it is mixed into the reactor charge and the oxidant is mixed into the reactor charge, e.g., via the water-phase feed.

Abstract: A process for feeding ethylene into a polymerization system includes providing a low-pressure ethylene stream, one or more low-pressure C3 to C20 monomer streams, an optional low-pressure inert solvent/diluent stream, and one or more reactors; metering the low-pressure ethylene stream, the one or more low-pressure C3 to C20 monomer streams, and the optional low-pressure inert solvent/diluent stream; blending the metered low-pressure ethylene stream, the metered one or more low-pressure C3 to C20 monomer streams, and the metered low-pressure optional inert solvent/diluent stream to form an ethylene-carrying low-pressure blended liquid feed stream; pressurizing the ethylene-carrying low-pressure blended liquid feed stream to the polymerization system pressure with one or more high-pressure pumps to thrm an ethylene-carrying high-pressure blended reactor feed stream; and feeding the ethylene-carrying high-pressure blended reactor feed stream to the one or more reactors.

Abstract: The present invention relates to a polymerization reactor for continuous polymerization, the reactor being constructed in two stages and comprising a prepolymerization stage which is configured as a stirred vessel or as a loop-type bubble column and also a main polymerization stage which is configured as a tubular reactor. Furthermore, the present invention relates to a method for the production of biodegradable polyester, in particular polylactide, the reactor according to the invention being used. Likewise, the invention relates to a polymerization device which comprises further components in addition to the polymerization reactor.

Abstract: A polymer having a melt index of from about 0.5 g/10 min to about 4.0 g/10 min and a density of equal to or greater than 0.96 g/cc which when formed into a 1-mil film displays a moisture vapor transmission rate ranging from equal to or greater than about 0 to equal to or about 20% greater than X where X=k1{?61.95377+39.52785(Mz/Mw)?8.16974(Mz/Mw)2+0.55114(Mz/Mw)3}+k2{?114.01555(?)+37.68575(Mz/Mw)(?)?2.89177(Mz/Mw)2(?)}+k3{120.37572(?)2?25.91177(Mz/Mw)(?)2}+k4{18.03254(?)3} when Mw is from about 100 kg/mol to about 180 kg/moL; Mz is from about 300 kg/mol to about 1000 kg/mol; ? is from about 0.01 S to about 0.35 s; k1 is 1 g/100 in2·day; k2 is 1 g/100 in2·day·s; k3 is 1 g/100 in2·day·s2; and k4 is 1 g/100 in2·day·s3.

Abstract: The present invention relates to a polymer composition, comprising (i) a polypropylene homopolymer, (ii) a polypropylene random copolymer, prepared by copolymerization of propylene with an olefin comonomer and having an amount of olefin comonomer units of 0.2 to 5 wt %, and (iii) an elastomeric copolymer of propylene and at least one olefin comonomer, the polymer composition having a tensile modulus, determined according to ISO 527-2/1B at 1 mm/min. and 23° C., of at least 1200 MPa.

Abstract: [Summary] The present invention relates to an apparatus for manufacturing polymer particles and a method for manufacturing the same. The present invention provides an apparatus and a method, by which polymer particles having excellent monodispersity and homogeneous physical properties, such as homogeneous cross-linking degree and polymerization degree, may be efficiently prepared. In the present invention, particles having excellent monodispersity with the desired particle diameter, and also having a high cross-linking degree or a core-shell or core-double shell structure may also be effectively prepared. In addition, the processes for manufacturing said polymer particles are exceptionally reproducible in the present invention.

Abstract: Disclosed is an apparatus for producing a high-quality methacrylic polymer with good productivity, comprising a complete mixing type reactor 11, tubular reactors 12 and 13 which have been serially connected, and a volatile removing instrument 14, wherein at least two of the tubular reactors 12 and 13 are connected via a cooler 15 for cooling the reaction mixture. It is preferable that the cooler 15 is a multitubular cooler and the tubular reactors 12 and 13 are plug flow reactors.

Abstract: The present invention relates to a process for improving the devolatilization of polymer slurry produced in an olefin polymerization reactor. The process is characterized in that it involves an adjustment of the temperature of the interior surface of the flash line for periodically transferring polymer slurry from the polymerization reactor to a downstream processing unit. In particular, in accordance with the present process, the temperature of the interior surface of the flash line is adjusted to a temperature which is equal to or higher than the softening temperature of the polymer passing through said flash line whereby said temperature is higher in a first half of the length of the flash line than in the remaining length of the flash line.

Abstract: The present invention relates to a reactor, and in particular to a slurry loop polymerisation reactor which comprises: a) a reaction zone in the form of a slurry loop, b) at least one feed inlet for monomers, comonomers and diluent, c) at least one catalyst inlet for polymerisation catalyst, and d) at least one discharge conduit for removal of polymer, characterised in that the at least one catalyst inlet is in the form of an inlet pipe and no part of the inlet pipe protrudes beyond the wall of the reaction zone and into the reaction zone by more than 1/10th of the diameter of the reaction zone at the point where the inlet pipe joins the reaction zone.

Abstract: The present invention discloses catalyst compositions employing silicon-bridged metallocene compounds with bulky substituents. Methods for making these silicon-bridged metallocene compounds and for using such compounds in catalyst compositions for the polymerization of olefins also are provided.

Abstract: The present invention relates to a process for improving the polymerization of ethylene and one or more optional co-monomer(s) in a polymerization loop reactor characterized in that said process comprises the step of controlling the hydrogen/monomer ratio along the path of the reactor by multiple, spatially separated, feeding of hydrogen along the path of the loop reactor. In particular, the invention provides a process for controlling, and preferably narrowing, the molecular weight distribution of the produced polymer particles. In another aspect, the invention relates to a polymerization loop reactor suitable for the polymerization process of ethylene and an optional olefin co-monomer, wherein the molecular weight distribution of the produced ethylene polymer can be controlled.

Abstract: Process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, by passing the stream through a heater having at least one transfer line for the stream and a heater for heating the transfer line. The average particle size of the solid polymer is less than 3mm, the mass flowrate of the polymer-containing stream exiting the heater is no more than 15% greater than the mass flowrate exiting the reactor, the average velocity of the polymer-containing stream either at a point 80% along the length of the heated part of the transfer line measured from the transfer line inlet, or at the transfer line outlet, is at least 6 m/s, and the pressure drop across the transfer line per unit length is between 0.0125 bar/m and 0.1 bar/m.

Abstract: The invention relates to a process for preparing polyolefin in a loop reactor. The polymer is prepared by polymerizing olefin monomers in the presence of a catalyst to produce a polyolefin slurry while pumping said slurry through said loop reactor by means of a pump. The present process is characterized in that the catalyst is fed in the loop reactor at a distance to the pump. The invention allows production of the polymer with advantageous properties while leading to fewer blockages of the reactor.

Abstract: The present invention provides a process for preparing high melt strength propylene polymer by direct polymerization, comprising that a propylene polymer with wide molecular weight distribution and containing “very high molecular weight fraction” can be prepared by controlling the species and ratios of the external electron donors in the Ziegler-Natta catalyst system at different reaction stages according to the requirment for different molecular weight fractions in the different propylene polymerization stage of the series operation, and said polymer has excellent mechnical properties, especially with very high melt strength. The present invention also provides a propylene homopolymer with high melt strength, comprising the following features: (1) the MFR is 0.2-10 g/10 min at 230° C. with a load of 2.16 kg; (2) the molecular weight distribution Mw/Mn is 6-20; (3) the content of the fraction with a molecular weight higher than 5,000,000 is higher than or equal to 0.

Abstract: The present invention provides a Mo—Bi—Nb based composite metal oxide (with the proviso that Te is not included); a method for producing (meth)acrylic acid from at least one reactant selected from the group consisting of propylene, propane, isobutylene, t-butyl alcohol and methyl-t-butyl ether, in which a Mo—Bi—Nb based composite metal oxide (with the proviso that Te is not included) is used as a catalyst; and a reactor used for producing (meth)acrylic acid from at least one reactant selected from the group consisting of propylene, propane, isobutylene, t-butyl alcohol and methyl-t-butyl ether, in which a Mo—Bi—Nb based composite metal oxide (with the proviso that Te is not included) is used as a catalyst. Further, the present invention provides a method for producing the (meth)acrylic acid without any additional process of converting (meth)acrolein into (meth)acrylic acid.

Abstract: An olefin polymerization process and apparatus wherein a fluid slurry comprising monomer, diluent and catalyst is circulated in a continuous loop reactor by two or more pumps. The process and apparatus allow operating the reaction at significantly higher solids content in the circulating fluid slurry. In a preferred embodiment, the fluid slurry is circulated by two impellers arranged so that the downstream impeller benefits from the rotational energy imparted by the upstream impeller. An olefin polymerization process operating at higher reactor solids by virtue of more aggressive circulation has improved efficiencies, particularly in larger-volume reactors.

Abstract: Process for polymerising, in a loop reactor, at least one olefin monomer in a liquid diluent to produce a slurry comprising solid particulate olefin polymer and said diluent, wherein the ratio between the actual volumetric solids concentration of the slurry and the maximum possible geometric volume solids concentration of the slurry as measured by the bulk density of an unpacked settled bed of particles, SVCR, is V*0.065 or greater, and the ratio of the cumulative settling distance of an average size particle at any point in the reactor in any direction perpendicular to the direction of the flow, to the internal diameter of the loop reactor, is maintained below [0.084*(V?6.62)+(0.69?SVCR)* 1.666], where V is the circulation velocity of the slurry in m/s and “cumulative settling distance” is defined as the cumulative distance, expressed as a fraction of the diameter, travelled by a particle in any direction perpendicular to the direction of the flow since the previous upstream pump.

Abstract: Techniques and systems for producing a polyolefin using reactors in series are described. Described embodiments include techniques and systems for polymerizing a monomer in a first polymerization reactor to form a first polyolefin, discharging a first slurry continuously from the first polymerization reactor to a second polymerization reactor, and discharging a second slurry continuously from the second polymerization reactor. Using continuous take-off devices disposed on either or both reactors, pressure control may be attained such that the rate of transfer between and withdrawal from both reactors are within a desired range.

Abstract: A thermoplastic copolymer having an excellent balance among properties such as coating resistance, color stability and fluidity and having high operability and productivity can be obtained by a method for producing a thermoplastic copolymer, comprising step (I) of supplying a monomer mixture (a) containing an aromatic vinyl monomer (a1) and a vinyl cyanide monomer (a2) to a complete mixing type reactor continuously to produce a copolymer (A) and step (II) of supplying the copolymer (A) continuously to a tubular reactor with a static mixing structure therein, which is placed in series with the complete mixing type reactor, and reacting the copolymer (A) to produce a copolymer (B).

Abstract: The present invention provides polymerization catalyst compositions employing novel dinuclear metallocene compounds. Methods for making these new dinuclear metallocene compounds and for using such compounds in catalyst compositions for the polymerization and copolymerization of olefins are also provided.

Abstract: The present invention relates to a method for optimizing the sequential use of at least two ethylene polymerization catalysts to an ethylene polymerization loop reactor, comprising: transferring to a mixing vessel a first ethylene polymerization catalyst and a first diluent, thereby providing a first catalyst slurry, transferring said first catalyst slurry from said mixing vessel to an ethylene polymerization loop reactor at a concentration suitable for polymerizing ethylene, increasing the ratio of said diluent to said first ethylene polymerization catalyst in said first catalyst slurry, stopping the supply of said first catalyst slurry to said mixing vessel, stopping the supply of said first catalyst slurry to said ethylene polymerization loop reactor, stopping the supply of ethylene to said ethylene polymerization loop reactor, removing said first catalyst slurry from said ethylene polymerization loop reactor, emptying said mixing vessel, optionally rinsing said mixing vessel with fresh diluent, transfe

Abstract: An apparatus defined as a set of loop reactors suitable for the polymerization process of a monomer, preferably ethylene and optionally an olefin co-monomer, comprising for each of said reactors: a plurality of interconnected pipes P defining a flow path for a polymer slurry, said slurry consisting essentially of ethylene, optionally a co-monomer, a polymerization catalyst, liquid diluent and solid olefin polymer particles, means for feeding monomer, optionally a co-monomer, diluent and optionally hydrogen in the reactor, means for feeding a polymerization catalyst in the reactor, a pump suitable for maintaining the polymer slurry in circulation in such reactor, one or more settling legs connected to the pipes P of such reactor for settling of polymer slurry, one or more control valves connected to the outlet of such settling legs, and one or more flash lines for discharging settled polymer slurry out of the reactor characterized in that each of said loop reactors comprises a three-or-more-way valve defini

Abstract: The present invention relates to a reactor (10) and a process for continuous polymerization, where the reactor (10) has an essentially tubular reactor housing (16). The reactor housing (16) has a drive (38) which runs along the geometric central axis (12) in the flow direction (22) and is configured as a central shaft. A rotatably arranged scraper or wiper (36) is provided within the reactor housing (16); the scraper or wiper (36) has at least one scraper or wiper blade (42) to run along an interior side (44) of the reactor housing (16). The rotational movement of the scraper or wiper (36) results in radial mixing of a stream within the reactor housing (16) which dominates gravity effects and, by virtue of shaping of the scrapers or wipers, optionally makes plug flow or backflow within the reactor (10) possible.

Abstract: The present invention relates to a process which comprises preparing polymers. The process uses an appropriate installation, and may comprise determining at least one parameter of a physical and/or chemical conversion. The invention also relates to a corresponding screening process. According to this process, a polymerization reaction medium is made to flow in a tubular flow member.

Abstract: A method for removing contaminants from a process stream that includes the use of reticulated material to filter the process stream in a vessel located upstream of a process unit. The reticulated material can be used with other conventional filter media within the vessel.

Abstract: Copolymers of ethylene and ?-olefins are provided having (a) a density (D) in the range 0.900-0.940 g/cm3, (b) a melt index MI2 (2.16 kg, 190° C.) in the range of 0.01-50 g/10 min, (c) a melt index MI2 (2.16 kg, 190° C.) and Dow Rheology Index (DRI) satisfying the equation [DRI/MI2]>2.65, and (d) a Dart Drop Impact (DDI) in g of a blown film having a thickness of 25 ?m produced from the copolymer satisfying the equation DDI?1900×{1?Exp[?750(D?0.908)2]}×{Exp[(0.919?D)/0.0045]}. The copolymers may suitably be prepared by use of metallocene catalysis and are preferably prepared in multistage processes earned out in loop reactors in the slurry phase. The copolymers exhibit long chain branching as defined by Dow Rheology Index (DRI) and exhibit unexpected improvements in mechanical properties, in particular dart drop impact, when extruded into blown films.

Abstract: A polyethylene resin having a multimodal molecular weight distribution comprising at least two polyethylene fractions A and B, fraction A being substantially free of comonomer and having a lower weight average molecular weight and a higher density than fraction B, each fraction prepared in different reactors of two reactors connected in series in the presence of a Ziegler-Natta catalyst system, the polyethylene resin having a density of from 0.950 to 0.965 g/cm3 and a melt index MI2 of from 0.5 to 5 g/10 min.

Abstract: Process for the preparation of a polypropylene, wherein propylene is polymerised optionally with a comonomer selected from the group consisting of ethylene, a C4-C20 ?-olefin and mixtures thereof, in the presence of a catalyst system comprising solid catalyst particles, wherein the solid catalyst particles (a) comprise a transition metal compound of formula (I) LmRnMXq (I) wherein “M” is a transition metal of anyone of the groups 3 to 10 of the periodic table (IUPAC), each “X” is independently a monovalent anionic ?-ligand, each “L” is independently an organic ligand which coordinates to the transition metal (M), each “R” is a bridging group linking two organic ligands (L), “m” is 2 or 3, preferably 2, “n” is 0, 1 or 2, preferably 1, “q” is 1, 2 or 3, preferably 2, m+q is equal to the valency of the transition metal (M), (c) comprise a cocatalyst (Co) comprising an element (E) of group 13 of the periodic table (IUPAC), preferably a cocatalyst (Co) comprising a compound of Al, wherein further the loss of activ

Abstract: The present invention relates to a process for cleaning a catalyst slurry preparation system and/or a catalyst preparation system. More particularly, the invention relates to a cleaning process for a catalyst preparation system and/or for a catalyst slurry preparation system, wherein an aqueous catalyst inactivation agent is used to rinse the systems, or any parts thereof. The catalysts used in the present invention may be chromium, Ziegler-Natta or metallocene catalysts.

Abstract: The invention relates to a process for the preparation of a particulate polyethylene product in a loop reactor, wherein the polymerization catalyst applied in the polymerization process comprises a particulate metallocene-alumoxane catalyst immobilized on a porous silica support; and whereby said metallocene-alumoxane catalyst is heterogeneously distributed on said porous silica support.

Abstract: Provided is a tubular flow reactor containing: a cylindrical channel; a mixing shaft which is concentric with the cylindrical channel; and a mixing blade attached to the mixing shaft, wherein the tubular flow reactor satisfy the following requirements: t<2C and t/2C<A/C?1, provided that C is a radius of the mixing shaft, t is a thickness of the mixing blade; A is a distance between a mixing blade plane B located at a forward position in a rotating direction of the mixing blade and a plane S passing through the center of the mixing shaft in a shaft direction, when plane B and plane S are parallel; and the mixing blade plane B is located at a more forward position in the rotating direction than the plane S.

Abstract: The present invention relates to a method for initiating an ethylene polymerization reaction in an ethylene polymerization loop reactor. More particularly, the invention relates to the timing upon which hydrogen is introduced into the ethylene polymerization loop reactor. The catalysts used in the ethylene polymerization reaction according to present invention are preferably metallocene catalysts.