| As a special configuration of fully thermally coupled distillation,dividing wall column(DWC)can improve the reversibility of the distillation effectively,and has high energy efficiency.Its energy efficiency can be further improved by the vapor recompression(VRC).However the large temperature difference between the overhead and bottom hinder their combination effectively.This paper mainly investigate the vapor recompression assisted dividing wall column with intermediate exchanger,in which the intermediate component stage is set as the connection position of vapor recompression and DWC,and four corresponding types of VRC assisted DWC configurations are proposed.On one hand,the liquid or vapor flow of the side product stage is purer than that from other side stage,the driving force of heat transfer can be maintained in phase-changed process;on the other hand,the temperature difference between the side product stage and each end of column is always smaller than that between two ends of column,the energy efficiency is higher.In order to obtain the higher energy efficiency configuration,the CGCC profiles are used to determine the types of withdrawn phase from middle product stage.Three cases for separating three kinds of ternary mixtures are introduced to evaluate the proposed configurations.The simulation results show that the vapor recompression assisted DWC with intermediate exchanger have high energy efficiency and low capital investment compared with conventional VRC system,especially under higher reflux ratio.The simulation results also show that the vapor recompression has small influence to the gas-liquid phase flow rate of prefractionator. |
