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.

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.

Methods for separating gaseous components, such as unreacted hydrocarbon monomer and/or solvent, from polyolefin solids are provided. The methods include contacting a first stream including polyolefin solids and gaseous unreacted hydrocarbon monomer and/or solvent with a first purge gas in a gas-solid separation vessel to separate the gaseous unreacted hydrocarbon monomer and/or solvent from the polyolefin solids to produce a second stream including polyolefin solids substantially free of gaseous unreacted hydrocarbon monomer and/or solvent and a third stream including the gaseous unreacted hydrocarbon monomer and/or solvent. The first purge gas includes hydrocarbon monomer and/or solvent and has a temperature of at least about 70° C. when entering the gas-solid separation vessel. Systems for carrying out such methods are also provided.

A process for preparing a multimodal ethylene copolymer in suspension in a reactor cascade including a first polymerization reactor and subsequent polymerization reactor(s) including polymerizing ethylene and C.sub.3-C.sub.12-1-alkenes and forming a suspension of multimodal ethylene copolymer particles in a suspension medium made from or containing a diluent, transferring the suspension into a separator, wherein the suspension is separated into multimodal ethylene copolymer particles and recovered suspension medium, purifying part of the recovered suspension medium for producing purified components of the recovered suspension medium, and recycling part of the purified components of the recovered suspension medium to the first polymerization reactor of the reactor cascade, wherein the purified components of the recovered suspension medium recycled to the first polymerization reactor and made from or containing the diluent, undergo catalytic hydrogenation before being introduced into the first polymerization reactor.

A process for preparing a multimodal ethylene copolymer in suspension in a reactor cascade including a first polymerization reactor and subsequent polymerization reactor(s) including polymerizing ethylene and C.sub.3-C.sub.12-1-alkenes and forming a suspension of multimodal ethylene copolymer particles in a suspension medium made from or containing a diluent, transferring the suspension into a separator, wherein the suspension is separated into multimodal ethylene copolymer particles and recovered suspension medium, purifying part of the recovered suspension medium for producing purified components of the recovered suspension medium, and recycling part of the purified components of the recovered suspension medium to the first polymerization reactor of the reactor cascade, wherein the purified components of the recovered suspension medium recycled to the first polymerization reactor and made from or containing the diluent, undergo catalytic hydrogenation before being introduced into the first polymerization reactor.

A copolymer has low levels of cyclic oligomeric compounds, which are undesirable impurities in certain applications. The cyclic oligomeric compounds are provided in an advantageously low ratio of C21/C13 oligomers. The C13 oligomers are extractable using steam to further reduce the total amount of cyclic oligomers. A process for producing the copolymer having low levels of cyclic oligomers involves contacting at least one isoolefin monomer with at least one multiolefin and/or β-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluorinated olefin (HFO) comprising at least three carbon atoms and at least three fluorine atoms. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydrofluorocarbons.

A copolymer has low levels of cyclic oligomeric compounds, which are undesirable impurities in certain applications. The cyclic oligomeric compounds are provided in an advantageously low ratio of C21/C13 oligomers. The C13 oligomers are extractable using steam to further reduce the total amount of cyclic oligomers. A process for producing the copolymer having low levels of cyclic oligomers involves contacting at least one isoolefin monomer with at least one multiolefin and/or β-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluorinated olefin (HFO) comprising at least three carbon atoms and at least three fluorine atoms. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydrofluorocarbons.

A process for preparing a multimodal ethylene copolymer in suspension in a reactor cascade including a first polymerization reactor and subsequent polymerization reactor(s) including polymerizing ethylene and C.sub.3-C.sub.12-1-alkenes and forming a suspension of multimodal ethylene copolymer particles in a suspension medium made from or containing a diluent, transferring the suspension into a separator, wherein the suspension is separated into multimodal ethylene copolymer particles and recovered suspension medium, purifying part of the recovered suspension medium for producing purified components of the recovered suspension medium, and recycling part of the purified components of the recovered suspension medium to the first polymerization reactor of the reactor cascade, wherein the purified components of the recovered suspension medium recycled to the first polymerization reactor and made from or containing the diluent, undergo catalytic hydrogenation before being introduced into the first polymerization reactor.

A process for preparing a multimodal ethylene copolymer in suspension in a reactor cascade including a first polymerization reactor and subsequent polymerization reactor(s) including polymerizing ethylene and C.sub.3-C.sub.12-1-alkenes and forming a suspension of multimodal ethylene copolymer particles in a suspension medium made from or containing a diluent, transferring the suspension into a separator, wherein the suspension is separated into multimodal ethylene copolymer particles and recovered suspension medium, purifying part of the recovered suspension medium for producing purified components of the recovered suspension medium, and recycling part of the purified components of the recovered suspension medium to the first polymerization reactor of the reactor cascade, wherein the purified components of the recovered suspension medium recycled to the first polymerization reactor and made from or containing the diluent, undergo catalytic hydrogenation before being introduced into the first polymerization reactor.

A process for preparing a multimodal ethylene copolymer in suspension in a reactor cascade including a first polymerization reactor and subsequent polymerization reactor(s) including polymerizing ethylene and C.sub.3-C.sub.12-1-alkenes and forming a suspension of multimodal ethylene copolymer particles in a suspension medium made from or containing a diluent, transferring the suspension into a separator, wherein the suspension is separated into multimodal ethylene copolymer particles and recovered suspension medium, purifying part of the recovered suspension medium for producing purified components of the recovered suspension medium, and recycling part of the purified components of the recovered suspension medium to the first polymerization reactor of the reactor cascade, wherein the purified components of the recovered suspension medium recycled to the first polymerization reactor and made from or containing the diluent, undergo catalytic hydrogenation before being introduced into the first polymerization reactor.