Cascade equilibrium stage relaxation method by introducing equilibrium efficiency parameter  

作　　者：Xuepu Cao Shengkun Jia Xing Qian Yiqing Luo Xigang Yuan 

机构地区：[1]College of Chemical and Pharmaceutical,Hebei University of Science&Technology,Shijiazhuang 050018,China [2]School of Chemical Engineering and Technology,State Key Laboratory of Chemical Engineering,Tianjin University,Tianjin 300072,China [3]College of Information Science and Technology,Beijing University of Chemical Technology,Beijing 100029,China

出　　处：《Chinese Journal of Chemical Engineering》2024年第2期145-156,共12页中国化学工程学报（英文版）

基　　金：Support by the National Natural Science Foundation of China(22308251,22178247,22378304);the Natural Science Foundation of Hebei Province(B2021208026)。

摘　　要：Optimizing multistage processes,such as distillation or absorption,is a complex mixed-integer nonlinear programming(MINLP)problem.Relaxing integer into continuous variables and solving the easier nonlinear programming(NLP)problem is an optimization idea for the multistage process.In this article,we propose a relaxation method based on the efficiency parameter.When the efficiency parameter is 1or 0,the proposed model is equivalent to the complete existence or inexistence of the equilibrium stage.And non-integer efficiency represents partial existence.A multi-component absorption case shows a natural penalty for non-integer efficiency,which can assist the efficiency parameter converging to 0 or 1.However,its penalty is weaker than the existing relaxation models,such as the bypass efficiency model.In a simple distillation case,we show that this property can weaken the nonconvexity of the optimization problem and increase the probability of obtaining better optimization results.

关 键 词：Mathematical modeling ABSORPTION DISTILLATION Optimization 

分 类 号：TQ02[化学工程]