US 12,221,500 B2
Suspension process for preparing ethylene polymers comprising drying of the polymer particles
Peter Rohrbach, Hofheim/Ts. (DE); Jürgen Perzlmeier, Neustadt/Donau (DE); Mudit Ashtana, LM Den Haag (NL); Harald Prang, Erftstadt (DE); and Elke Damm, Bad Vilbel (DE)
Assigned to Basell Polyolefine GmbH, Wesseling (DE)
Appl. No. 17/614,684
Filed by Basell Polyolefine GmbH, Wesseling (DE)
PCT Filed May 28, 2020, PCT No. PCT/EP2020/064794
§ 371(c)(1), (2) Date Nov. 29, 2021,
PCT Pub. No. WO2020/239887, PCT Pub. Date Dec. 3, 2020.
Claims priority of application No. 19177329 (EP), filed on May 29, 2019.
Prior Publication US 2022/0227903 A1, Jul. 21, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C08F 210/16 (2006.01); C08F 2/01 (2006.01); C08F 2/18 (2006.01); C08F 210/08 (2006.01)
CPC C08F 210/16 (2013.01) [C08F 2/01 (2013.01); C08F 2/18 (2013.01); C08F 210/08 (2013.01); C08F 2500/05 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A process for preparing an ethylene polymer in a suspension polymerization in a polymerization reactor or a series of polymerization reactors comprising the steps of:
polymerizing ethylene or copolymerizing ethylene and one or more C3-C12-1-alkenes at temperatures of from 40 to 150° C. and pressures of from 0.1 to 20 MPa in the presence of a polymerization catalyst and forming a suspension of ethylene polymer particles in a suspension medium comprising a hydrocarbon diluent,
transferring the suspension of ethylene polymer particles into a solid-liquid separator, wherein the suspension is separated into wet ethylene polymer particles and mother liquor,
drying the wet ethylene polymer particles by contacting the particles with a gas stream, thereby forming a gas stream carrying a hydrocarbon load, and thereafter separating the hydrocarbon load from the gas stream, thereby forming a liquid hydrocarbon recover stream,
transferring a first part of the mother liquor into a work-up section comprising 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, and
recycling a first part of the isolated diluent produced in the diluent distillation unit to the polymerization reactor or the series of polymerization reactors,
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.