Mechanism analysis of solvent selectivity and energy-saving optimization in vapor recompression-assisted extractive distillation for separation of binary azeotrope  

作　　者：Xiaomin Qiu Yuanyuan Shen Zhengkun Hou Qi Wang Zhaoyou Zhu Yinglong Wang Jingwei Yang Jun Gao 

机构地区：[1]College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao 266042,China [2]College of Chemical and Environmental Engineering,Shandong University of Science and Technology,Qingdao 266590,China

出　　处：《Chinese Journal of Chemical Engineering》2022年第6期271-279,共9页中国化学工程学报（英文版）

基　　金：This work is supported by the National Natural Science Foundation of China(No.21776145);National Natural Science Foundation of China(No.21676152).

摘　　要：Octane and p-xylene are common components in crude gasoline,so their separation process is very important in petroleum industry.The azeotrope and near azeotrope are often separated by extractive distillation in industry,which can realize the recovery and utilization of resources.In this work,the vapor–liquid equilibrium experiment was used to obtain the vapor–liquid equilibrium properties of the difficult separation system,and on this basis,the solvent extraction mechanism was studied.The mechanism of solvent separation plays a guiding role in selecting suitable solvents for industrial separation.The interaction energy,bond length and charge density distribution of p-xylene with solvent are calculated by quantum chemistry method.The quantum chemistry calculation results and experiment results showed that N-formylmorpholine is the best solvent among the alternative solvents in the work.This work provides an effective and complete solvent screening process from phase equilibrium experiments to quantum chemical calculation.An extractive distillation simulation process with N-formylmorpholine as solvent is designed to separate octane and p-xylene.In addition,the feasibility and effectiveness of the intensified vapor recompression assisted extraction distillation are also discussed.In the extractive distillation process,the vapor recompression-assisted extraction distillation process is globally optimal.Compared with basic process,the total annual cost can be reduced by 43.2%.This study provides theoretical guidance for extractive distillation separation technology and solvent selection.

关 键 词：Quantum chemical calculation Vapor liquid equilibria DISTILLATION Energy saving SEPARATION 

分 类 号：TE626.21[石油与天然气工程—油气加工工程] TQ028.3[化学工程]