Abstract: An apparatus for the gas-phase polymerization of olefins including a reactor having a polymerization zone, a recycle line for withdrawing reaction gas from the reactor and feeding the reaction gas back into the reactor, a compressor for conveying the reaction gas along the recycle line, and a heat exchanger for cooling the reaction gas, wherein at least part of the internal surface of the recycle line, which comes in contact with the reaction gas, has a surface roughness Ra of less than 5 ?m.

Abstract: A process for producing articles with an extrusion-based additive manufacturing system using a consumable filament made from or containing a propylene polymer composition made from or containing: A) from 20% to 60% by weight of a heterophasic propylene copolymer; B) from 5% to 33% by weight of a propylene homopolymer or copolymer, wherein the copolymer contains up to 5% by weight of an alpha olefin; C) from 2% to 15% by weight of an elastomeric block copolymer made from or containing styrene; D) from 4% to 32% by weight of an elastomeric ethylene copolymer; E) from 5% to 50% by weight of a glass material as filler; and F) from 0.1% to 5% by weight of compatibilizer.

Abstract: A process for preparing an ethylene polymer in a suspension polymerization including the steps of separating the formed suspension of ethylene polymer particles in a solid-liquid separator into wet ethylene polymer particles and mother liquor, transferring a part of the mother liquor into a work-up section including an evaporator for producing a wax-depleted portion of the mother liquor, a diluent distillation unit for producing isolated diluent from the wax-depleted portion of the mother liquor, and a wax removal unit operated by direct steam distillation for producing a gaseous hydrocarbon/steam mixture which is condensed and then separated into an aqueous phase and a hydrocarbon phase, wherein a first part of the hydrocarbon phase is transferred to the diluent distillation unit without passing the evaporator for producing the wax-depleted portion of the mother liquor.

Abstract: A process for polymerizing or copolymerizing ethylene in a slurry polymerization in a reactor system including a polymerization reactor, one or more first heat exchangers located outside the polymerization reactor, and a closed loop of a tempering medium for cooling or heating the first heat exchangers, which closed loop is equipped with second heat exchangers for cooling the tempering medium and third heat exchangers for heating the tempering medium, and wherein, during the polymerization, the slurry is cooled in the first heat exchangers, the temperature of the tempering medium cooling the first heat exchangers is in the range from 20° C. to 50° C., and the tempering medium is cooled in the second heat exchangers by a coolant, having a temperature from ?20° to 45°° C.

Abstract: A process for preparing an ethylene polymer in a suspension polymerization including the steps of separating the formed suspension of ethylene polymer particles in a solid-liquid separator into wet ethylene polymer particles and mother liquor, drying the wet ethylene polymer particles by a gas stream and forming a gas stream carrying a hydrocarbon load, and thereafter separating the hydrocarbon load from the gas stream and thereby forming a liquid hydrocarbon recover stream, transferring a part of the mother liquor into a work-up section including an evaporator for producing a wax-depleted portion of the mother liquor and a diluent distillation unit for producing isolated diluent from the wax-depleted portion of the mother liquor, wherein a first part of the hydrocarbon recover stream is transferred to the diluent distillation unit without passing the evaporator for producing the wax-depleted portion of the mother liquor.

Abstract: Embodiments of the present disclosure relate to a method of preparing polyethylene compositions comprising polymerizing ethylene in a first gas-phase reactor and polymerizing ethylene in a second gas-phase reactor in the presence of hydrogen; wherein at least one of the first or second gas-phase reactors comprises a first and second polymerization zone; wherein a hydrogen pressure of the first and second polymerization zones are different such that at least a portion of the second ethylene cycles through the first and second polymerization zones and a gas mixture of each polymerization zone is partially or totally prevented from entering the other zone.

Abstract: A polyolefin composition (I) made from or containing: (A) 15-80% by weight of a heterophasic polymer composition made from or containing: (a) 50-80% by weight of a propylene polymer, and (b) 20-50% by weight of a copolymer of ethylene and an alpha-olefin; and (B) 20-85% by weight of a polyethylene composition made from or containing: (i) 25-85% by weight of a polyethylene component, having a weight average molecular weight Mw(i), equal to or higher than 1,000,000 g/mol; and (ii) 10-65% by weight of a polyethylene component, having an Mw(ii) equal to or lower than 5,000 g/mol, wherein the polyethylene composition (B) is made from or containing at least 70% by weight of (i)+(ii).

Abstract: An extrusion additive manufacturing process including the step of extruding a polyethylene composition having a melt flow index MIE of at least 0.1 g/10 min., the composition made from or containing: A) from 1% to 40% by weight of a polyethylene component having a weight average molar mass Mw, as measured by GPC (Gel Permeation Chromatography), equal to or higher than 1,000,000 g/mol; B) from 1% to 95% by weight of a polyethylene component having a Mw value from 50,000 to 500,000 g/mol; and C) from 1% to 59% by weight of a polyethylene component having a Mw value equal to or lower than 5,000 g/mol.

Abstract: A polyethylene composition made from or containing: A) from 85% to 99% by weight of an ethylene polymer composition made from or containing: AI) from 80 to 95% by weight of an ethylene polymer component, having a density DI from 952 to 965 kg/m3 and a MIF of from 10 to 35 g/10 min.; and AII) from 5 to 20% by weight of an ethylene polymer component, having a density DII from 940 to 950 kg/m3 and a MIF value lower than the MIF value of AI); wherein the amounts of AI) and AII) are referred to the total weight of AI)+AII); and B) from 1% to 15% by weight of a butene-1 polymer component.

Abstract: A polyethylene composition having the following features: 1) a density from 0.957 to 0.968 g/cm3; 2) a ratio MIF/MIP from 12 to 30; 3) a MIF from 41 to 60 g/10 min.; 4) a long-chain branching index, LCBI, equal to or greater than 0.45; and 5) a ratio (?0.02/1000)/LCBI from 45 to 75.

Abstract: The present disclosure refers to transfer line exchangers with improved cooling capacity, equipped with a thermal spray coating in crackers and a method for the maintenance of transfer line exchangers with the help of a thermal spray coating. In some embodiments, the thermal spray coating is obtained from a spray material formed of Cr3C2 and a NiCr alloy. Preferably, the spray coating material comprises at least 60 wt.-%, preferably at least 70 wt.-% of Cr3C2, based on the total weight of the spray material.

Abstract: A process for polymerizing ethylene in a high-pressure polymerization system having a continuously operated polymerization reactor and a reactor blow down system having an emergency valve, a reactor blow down vessel containing an aqueous medium and a reactor blow down dump vessel, wherein the process includes the steps of monitoring the polymerization system for a disturbance, opening the emergency valve when a disturbance occurs to allow the content of the polymerization system to expand into the reactor blow down vessel, contacting the content of the polymerization system in the reactor blow down vessel with the aqueous medium to obtain an aqueous polymer slurry, separating the polymer slurry and gaseous components, and transferring the polymer slurry to the reactor blow down dump vessel.

Abstract: A process for preparation of an ethylene polymer in a gas-phase polymerization unit comprising a gas-phase polymerization reactor by homopolymerizing ethylene or copolymerizing ethylene and one or more C4-C12-1-alkenes in a reaction gas made from or containing propane as polymerization diluent in the presence of a pre-activated polymerization catalyst, wherein a purified propane feed stream made from or containing at least 99 mol % propane and from 0.1 to 100 ppm mol propylene is fed to the gas-phase polymerization unit.

Abstract: A multitubular heat exchanger for cooling a gas stream. including an inlet chamber: a bundle of tubes encased in a shell structure: and an outlet chamber, wherein (a) each tube has an inlet with a diameter of d1: a longitudinal middle part with a diameter of d2: an outlet: and (b) d1 is larger than d2.

Abstract: A process for preparing an olefin polymer in a polymerization apparatus in the presence of a solid particulate polymerization catalyst and an organometallic compound, including the steps of withdrawing a gaseous stream from the polymerization apparatus, passing the gaseous stream through a bed of particulate solid having, at the surface of the particulate solid, chemical groups which are reactive with the organometallic compound, and feeding a sample of the gaseous stream into an analyzer.

Abstract: An extrusion-based additive manufacturing process including the step of selectively depositing a molten thermoplastic material (P) on a film or sheet made from or containing a polymer blend obtained by melt blending a mixture made from or containing: (A) 60% to 98.8% by weight of a polyolefin; (B) 0.1% to 30% by weight of a compatibilizer; (C) 0.05% to 20% by weight of an amino resin; and (D) 0% to 5% by weight of an additive, wherein the amounts of (A), (B), (C) and (D) are based on the total weight of (A)+(B)+(C)+(D).

Abstract: A polyethylene composition for preparing filaments and fibers, made from or containing: A) from 65% to 97% by weight of a copolymer of ethylene having: 1) a density of 0.925 g/cm3 or higher; and 2) a MI2 value of 0.5 g/10 min. or greater; and B) from 3% to 35% by weight of a polyolefin composition made from or containing: BI) from 5% to 35% by weight of a propylene homopolymer; BII) from 20% to 50% by weight of an ethylene homopolymer or a copolymer of ethylene with up to 5% by weight of alpha-olefin comonomers, containing 5% by weight or less of a fraction soluble in xylene at 25° C.; and BIII) from 30% to 60% by weight of a terpolymer of ethylene, propylene, and 1-butene containing from 30% to 85% by weight of a fraction soluble in xylene at 25° C.

Abstract: A process for producing a low density polyethylene with modified melt flow index, comprising subjecting to thermal visbreaking a precursor polyethylene (I) comprising 35% by weight or more of LDPE and blending the so obtained intermediate polyethylene product (II) with an additional polyethylene (III).

Abstract: A process for producing a low density polyethylene with modified melt flow index, comprising subjecting to thermal visbreaking a precursor polyethylene (I) comprising 35% by weight or more of LDPE.

Abstract: An extrusion-based additive manufacturing process including the step of selectively depositing a molten thermoplastic material (P) on a film or sheet made from or containing a polymer blend obtained by melt blending a mixture made from or containing: (A) 60% to 98.8% by weight of a polyolefin; (B) 0.1% to 30% by weight of a compatibilizer; (C) 0.05% to 20% by weight of an amino resin; and (D) 0% to 5% by weight of an additive, wherein the amounts of (A), (B), (C) and (D) are based on the total weight of (A)+(B)+(C)+(D).