液液萃取-非均相共沸精馏耦合回收正丁酸

Recovery of n-butyric acid by combined process of liquid-liquid extraction and heterogeneous azeotropic distillation

正丁酸与水的混合物能够形成最低沸点共沸物,难以用传统精馏分离。在常规非均相共沸精馏基础上,文中提出了更为节能的液液萃取-非均相共沸精馏耦合技术,利用COSMO活度系数模型筛选出合适的溶剂,并探索了混合溶剂萃取精馏分离工艺。采用顺序迭代法优化工艺主要操作参数,使用经济和环境分析方法去评价分离过程的主要性能。单一溶剂液液萃取技术结合非均相共沸精馏技术,相比于传统非均相共沸精馏技术最低年总成本(TAC)显著降低31.70%,CO_(2)排放量显著降低52.09%。采用混合溶剂精馏工艺TAC降低33.42%,CO_(2)减排53.70%。结果表明:该工艺采用液液萃取-非均相共沸精馏耦合技术相比于传统分离方式节能降耗效果显著,经济和环保性能更为优良,能够满足清洁生产的要求。

The mixture of n-butyric acid and water can form the lowest boiling azeotrope,which is difficult to separate by conventional distillation.Based on the conventional heterogeneous azeotropic distillation,a more energy efficient liquid-liquid extraction and heterogeneous azeotropic distillation coupling technology was proposed.The suitable solvent was selected by using COSMO activity coefficient model,and the separation process of mixed solvent extractive distillation was explored.The main operation parameters of the process were optimized by sequential iteration method,the main performance of the separation process were evaluated by economic and environmental analysis methods.The minimum total annual cost(TAC)and CO_(2)emission of single solvent liquid-liquid extraction combined with heterogeneous azeotropic distillation were reduced by 31.70%and 52.09%compared with conventional azeotropic distillation.The TAC and CO_(2)emissions were reduced by 33.42%and 53.70%by using mixed solvent distillation.The results show that the liquid-liquid extraction and heterogeneous azeotropic distillation coupling technology can save energy and reduce consumption significantly compared with the traditional separation method,and has better economic and environmental performance,which can meet the requirements of cleaner production.