SYSTEMS AND METHODS FOR EXTRACTING POLYETHYLENE WITH A LOW VOLATILE MATTER CONTENT Russian patent published in 2022 - IPC C08F6/02 C08F6/10 C08F2/00 C08F10/02 B01J19/00 B01J8/08 

FIELD: physical processes.

SUBSTANCE: group of inventions relates to methods for removing volatile components from the effluent flow of ethylene polymer from an ethylene polymerisation reactor and to systems for extracting polyethylene and removing volatile matter; and, more specifically, relates to such systems and methods wherein the temperature of solid polymer particles increases significantly prior to introducing solid polymer particles into the bleaching tower in order to separate volatile components from solid polymer particles. Method for removing volatile components from the effluent flow of ethylene polymer from an ethylene polymerisation reactor includes the following stages: (i) reducing the pressure of the effluent flow in order to remove a first part of the volatile components from the solid polymer particles, wherein the solid polymer particles have a solid particle temperature from 10°F to 50°F below the reaction temperature in the ethylene polymerisation reactor; (ii) fluidising the solid polymer particles while heating in order to increase the temperature of the solid particles from at least 10°F above the temperature of the solid particles at stage (i) and up to 20°F above the reaction temperature, wherein a second part of the volatile components is removed; and (iii) bringing the heated solid polymer particles with the boiloff gas in order to remove the third part of the volatile components, forming a flow of solid polymer particles containing less than 100 ppm by weight (ppmw) of volatile components. In the alternative variant, the method for removing volatile components from the effluent flow of ethylene polymer from an ethylene polymerisation reactor includes the following stages: (I) bringing the effluent flow in contact with a fluidising gas at a reduced pressure while heated in order to remove an initial part of volatile components from the solid polymer particles, wherein the solid polymer particles have a solid particle temperature from 30°F below to 20°F above the reaction temperature in the ethylene polymerisation reactor; and (II) bringing the heated solid polymer particles in contact with the boiloff gas in order to remove the last part of volatile components, forming a flow of solid polymer particles containing less than 100 ppmw of volatile components. Also described are systems for extracting polyethylene and removing volatile matter, a polymerisation reactor system including the system for extracting polyethylene and removing volatile matter and an ethylene polymerisation reactor, and a method for polymerising ethylene.

EFFECT: effective removal of volatile components as a result of the increase in the temperature of solid polymer particles prior to introducing the solid particles into the bleaching tower, thereby also providing a possibility of significantly reducing the size of the bleaching tower without compromising the possibility of removing volatile matter.

20 cl, 2 ex, 2 dwg