新型乙二醇合成工艺的产品精制与节能技术

Energy-saving technologies for purification of crude ethylene glycol synthesized via novel pathways

乙二醇是一种重要的化工原料,用于制造聚酯、炸药、防冻剂、增塑剂等。本文总结了草酸酯催化加氢法、生物质催化加氢转化法等新型乙二醇合成工艺,综述了新路线中乙二醇粗产品所含的杂质种类与含量,分析了煤基乙二醇和生物质基乙二醇生产技术的分离单元所面临的具体问题及技术瓶颈。对比和分析了萃取精馏、反应精馏、共沸精馏等方法在乙二醇精制中的优缺点及应用前景,概述了多效精馏、热泵技术、热耦合等节能技术及其在乙二醇产品精制中的应用。针对常规方法难以分离的1,2-丙二醇、1,2-丁二醇,提出了通过设计、合成具有特定结构和活性位的催化剂、利用化学反应将二者转化、分离的建议。建议未来乙二醇生产技术的发展方向应该是低水耗、高选择性的合成工艺和高效节能的精制技术。

Mono-ethylene glycol(MEG)is an important chemical widely used for synthesizingpolyesters,explosives,antifreeze,plasticizer etc.The novel methods for MEG synthesis such ascatalytic hydrogenation of oxalic acid ester and catalytic hydrocracking of biomass were summarized.The impurities and their contents in the crude ethylene glycol product were discussed.The specificissues and technical bottlenecks in the separation units of the coal-and biomass-based MEG synthesispathways were analyzed.The advantages and disadvantages of separation methods in EG purification,such as extractive distillation,reactive distillation and azeotropic distillation,were compared andanalyzed from an industrial point of view.A variety of energy-saving techniques including multi-effectdistillation,heat pump,and thermally coupled distillation and their applications in EG purification werereviewed.Aiming at the removal of refractory1,2-propanediol and1,2-butanediol,it was proposed thatboth impurities can be converted and removed by catalytic reactions over catalysts rationally designedand synthesized with specific structures and active sites.It was suggested that the effectiveenergy-saving purification techniques with low-water-consumption and highly selective synthesispathways should be focused on in the EG production in the future.