Method and equipment for obtaining ethylene glycol and diethylene glycol from recovered solution

Abstract

The invention provides a method for obtaining ethylene glycol and diethylene glycol from a recovered solution, which comprises the following steps of: atmospheric distillation: carrying out atmospheric distillation on the recovered solution, and separating out methanol to obtain a first mixed solution; negative-pressure evaporation: carrying out negative-pressure evaporation on the first mixed solution, and separating out a steam substance which contains diethylene glycol and ethylene glycol; and negative-pressure rectification: carrying out negative-pressure rectification on the steam substance to separate out a second gas-phase substance and a second mixed solution containing diethylene glycol, the second gas-phase substance containing ethylene glycol. According to the method, the ethylene glycol and the diethylene glycol in the recovered solution are separated by adopting a normal-pressure rectification and negative-pressure film evaporation mode, and then the ethylene glycol is separated by virtue of negative-pressure rectification, so that the recovery rate of the ethylene glycol is 99% or above, and the recovery rate of the diethylene glycol is 70%-80%. The equipment can perform continuous operation to continuously extract ethylene glycol and diethylene glycol, and is high in working efficiency.

Description

technical field

[0001] The invention relates to the field of PET recycling, in particular to a method and equipment for obtaining ethylene glycol and diethylene glycol from the recovered liquid obtained by the continuous alcoholysis recovery method of waste polyester. Background technique

[0002] The Chinese name of PET is: polyethylene terephthalate, which belongs to polyester polyester. PET is widely used as fiber, and engineering plastic resin can be divided into two categories: non-engineering plastic grade and engineering plastic grade. Non-engineering plastic grade is mainly used for bottles, films, sheets, and baking-resistant food containers. PET chips are divided into fiber-grade polyester chips and non-fiber-grade polyester chips. Fiber-grade polyester is used to manufacture polyester staple fibers and polyester filaments, and is the raw material for polyester fiber enterprises to process fibers and related products. Polyester is the most produced variety in chem...

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