摘要:
A process for the preparation of an ethylene polymer in the presence of a Phillips-type chromium catalyst in a gas-phase polymerization reactor equipped with a cycle gas line including a heat- exchanger, wherein the cooled reactor gas returned to the polymerization reactor through the cycle gas line has been partly condensed and the amount of liquid in the returned reactor gas is from 0.5 wt.% to 1 0 wt.%, the polymerization is carried out at from 1 08 °C to 125 °C, and an aluminum alkyl is fed into the polymerization reactor in an amount in the range of from 0.0025 mole to 0.1 mole per ton of dosed ethylene.
摘要:
A polyethylene composition particularly suited for producing blow-molded hollow articles, having the following features: 1) density from greater than 0.952 to 0.957 g/cm3, determined according to ISO 1183-1 at 23°C; 2) ratio MIF/MIP from 12 to 25; 3) MIF from 18 to 40 g/10 min.; 4) η0.02 from 30,000 to 55,000 Pa.s; 5) long-chain branching index, LCBI, equal to or greater than 0.55; 6) ratio (η0.02/1000)/ LCBI from 55 to 75.
摘要:
A process for separating polymeric and gaseous components of a polymer-monomer mixture at a pressure of from 0.12 MPa to 0.6 MPa and a temperature of from 120° C. to 300° C. in a separation vessel is provided. The separation vessel has a vertically arranged cylindrical shape with a ratio of length to diameter L/D of from 0.6 to 10 and an inlet pipe capable of introducing the polymer-monomer mixture into the separation vessel which the inlet pipe extends vertically from the top of the separation vessel into the separation vessel. Further a process for preparing ethylene homopolymers or copolymers from ethylenically unsaturated monomers in the presence of free-radical polymerization initiators at temperatures from 100° C. to 350° C. and pressures in the range of from 110 MPa to 500 MPa comprising such a process for separating a polymer-monomer mixture is provided.
摘要:
A process for separating polymeric and gaseous components of a polymer-monomer mixture at a pressure of from 0.12 MPa to 0.6 MPa and a temperature of from 120° C. to 300° C. in a separation vessel is provided. The separation vessel has a vertically arranged cylindrical shape with a ratio of length to diameter L/D of from 0.6 to 10 and an inlet pipe capable of introducing the polymer-monomer mixture into the separation vessel which the inlet pipe extends vertically from the top of the separation vessel into the separation vessel. Further a process for preparing ethylene homopolymers or copolymers from ethylenically unsaturated monomers in the presence of free-radical polymerization initiators at temperatures from 100° C. to 350° C. and pressures in the range of from 110 MPa to 500 MPa comprising such a process for separating a polymer-monomer mixture is provided.
摘要:
Vessel for separating, at a pressure of from 10 MPa to 50 MPa, a composition comprising liquid components and gaseous components into a liquid fraction and a gaseous fraction, wherein the separation vessel has a cylindrical shape and is vertically arranged, the separation vessel has at its top a manhole, which is surrounded by a thickened part of the separation vessel wall; the separation vessel is equipped with means for introducing the composition into the separation vessel, with means for withdrawing a gaseous fraction from the top of the separation vessel, and with means for withdrawing a liquid fraction from the bottom of the separation vessel; and the separation vessel bears at least one bursting disc which is held by a bursting disc holder which is installed pressure-tight within a boring in the thickened part of the separation vessel wall, process for separating, at a pressure of from 10 MPa to 50 MPa, a composition comprising liquid components and gaseous components into a liquid fraction and a gaseous fraction, and process for preparing ethylene homopolymers or copolymers from ethylenically unsaturated monomers in the presence of free-radical polymerization initiators at temperatures from 100°C to 350°C and pressures in the range of from 1 10 MPa to 500 MPa in a polymerization reactor, wherein the separation of the reaction mixture obtained by the polymerization is carried out in such a separation vessel.