System for chemical method for preparing BHET monomer from waste PET material

The present invention provides a purification system for chemical method for preparing BHET monomer from a waste PET material. A PET quantitative feeding system and an ionic liquid catalyst quantitative feeding system are connected to an inlet of a degradation and filtration system through pipelines; an outlet of the degradation and filtration system is connected to an inlet of a degradation liquid cooling crystallization system by a pipeline; an outlet of the degradation liquid cooling crystallization system is connected with an inlet of a glycol and BHET separation circulation system through a pipeline; the degradation and filtration system comprises two parts, an upper degradation part of a reaction kettle structure and a lower filtration part of a net-type structure; the degradation liquid cooling crystallization system is a crystallization tower structure; and the glycol and BHET separation circulation system has a plate-and-frame filter press structure. The system of the present invention works under atmospheric pressure throughout the production process and does not involve a pressure vessel. The technical index of PET degradation rate is greater than 99%.