Process and system for generating BHET based on ester exchange of solid acid catalyst

The invention provides a process and a system for generating BHET based on ester exchange of a solid acid catalyst, and the process comprises the following steps: high-purity dimethyl terephthalate obtained by depolymerizing waste PET with the purity of more than 90% is catalyzed by a solid acid catalyst SO4 < 2->/TiO2, and dimethyl terephthalate and ethylene glycol are subjected to ester exchange reaction to generate a BHET monomer and methanol gas. The solid acid catalyst SO4 < 2->/TiO2 is insoluble in the reaction liquid, has high catalytic efficiency, can be conveniently separated from the reaction liquid for recycling, does not generate other waste liquid in the process flow, and is green and environment-friendly. 本发明提供了一种基于固体酸催化剂酯交换生成BHET的工艺和系统，所述工艺包括如下步骤：纯度90％以上的废旧PET解聚获得的高纯对苯二甲酸二甲酯在固体酸催化剂SO42-/TiO2催化下，对苯二甲酸二甲酯和乙二醇发生酯交换反应，产生BHET单体和甲醇气体。本发明固体酸催化剂SO42-/TiO2不溶于反应液，催化效率高，可以方便的从反应液中分离后循环使用，工艺流程无其余废液产生，绿色环保。