新型萃取精馏回收废水中乙腈工艺技术

New extractive distillation technology for acetonitrile recovery from wastewater

由于乙腈与水能形成共沸物,所以常规精馏工艺无法将其分离。本文研究了离心萃取与连续精馏相结合的分离工艺分离乙腈-水二元混合物。依据萃取剂成本低、易回收的原则,从一系列萃取剂中筛选出适合本组合工艺的萃取剂。实验结果表明,以二氯甲烷作为萃取剂,萃取有机相的微量水含量最低为0.4%;采用离心萃取法比普通搅拌萃取所得水相中乙腈含量低,为0.9%;连续精馏工艺提高了萃取剂的使用效率,乙腈回收率高于85%,萃取剂损失约15%,节能环保。

Because acetonitrile and water can form azeotrope,they cannot be separated by conventional distillation process.The topic studied the combination of centrifugal extraction and continuous distillation separation of acetonitrile-water binary mixture technology.Based on the principle of low cost and easy recovery of extractant,the suitable extractant for the combined process was selected from a series of extractants.The experimental results showed that with dichloromethane as extractant,the content of trace water in organic phase extraction was at least 0.4%;The content of acetonitrile in aqueous phase obtained by centrifugal extraction is 0.9%,lower than that obtained by ordinary stirring extraction;Continuous distillation process improves the use efficiency of extractants,acetonitrile recovery rate is higher than 85%,extraction agent loss about 15%,which is energy-saving and environmentally friendly.