SUSPENSION METHOD FOR PRODUCING ETHYLENE POLYMERS BASED ON DRYING POLYMER PARTICLES Russian patent published in 2023 - IPC C08F2/18 C08F6/24 C08F10/02 C08F110/02 C08F210/08 

FIELD: polymers.

SUBSTANCE: invention relates to a method for producing an ethylene polymer in the course of suspension polymerisation in a polymerisation reactor or in a cascade of polymerisation reactors. Method includes the following stages: performing polymerisation of ethylene or copolymerisation of ethylene and one or several C₃-C₁₂1-alkenes at a temperature from 40 to 150 °C and under a pressure of 0.1 to 20 MPa in the presence of a polymerisation catalyst, and forming a suspension from ethylene polymer particles in a suspension medium containing a hydrocarbon diluent; transferring the suspension of ethylene polymer particles to a solid/liquid separator wherein the suspension is divided into wet ethylene polymer particles and a mother solution; drying the wet ethylene polymer particles as a result of interaction of the particles with a gas flow and forming a hydrocarbon-carrying gas flow, followed by separating hydrocarbons from the gas flow, forming a flow of liquid extracted hydrocarbons; transferring part of the mother solution to a processing section containing the following: an evaporator for producing a paraffin-depleted part of the mother solution; a diluent distillation unit producing isolated diluent from the paraffin-depleted part of the mother solution; and resupplying at least part of the isolated diluent produced in the diluent distillation unit to the polymerisation reactor or to the cascade of polymerisation reactors, wherein part of the flow of extracted hydrocarbons is transferred to the diluent distillation unit as well as the evaporator, to produce a paraffin-depleted part of the mother solution.

EFFECT: development of a method for producing a mother solution produced by extracting the prepared ethylene polymer particles from the suspension produced in the course of ethylene polymerisation, not only providing a purified diluent, but also suitable for cost- and energy-efficient execution and able to minimise the amount of evaporated mother solution.

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