THE PROCESS FOR CHEMICAL RECYCLING OF POLY (ETHYLENE TEREPHTHALATE) WASTE STREAMS

摘要

The proposed method of chemical recycling of polyethylene terephthalate waste to terephthalic acid and ethandiol is based on a continuous series of gradual steps, namely (a) separation of the polyethylene terephthalate component of the input material by its conversion to brittle form through crystallization, grinding and subsequent sifting, followed by (b) continuous two-stage hydrolysis of the polyethylene terephthalate, carried out in the first stage by feeding steam to the polymer melt, and in the second stage, by the reaction of the products of the first stage of hydrolysis with ammonium hydroxide, followed by (c) condensation of terephthalic acid from an aqueous solution of the second-stage hydrolysis products by inorganic acid, and its separation by means of filtration, and finally (d) rectification separation of ethandiol from a solution of the products of the second stage of hydrolysis, after the separation of terephthalic acid.