Research On The Design And Optimization Of Distillation Process For Methanol-Methyl Ethyl Ketone-Water Azeotropic System

In the process of producing methyl isopropyl ketone and diethyl ketone,a large amount of industrial wastewater containing methanol and methyl ethyl ketone will be produced.Due to the existence of the azeotropes between methanol-methyl ethyl ketone and methyl ethyl ketone-water in the wastewater,conventional distillation techniques cannot effectively separate them.Therefore,in this article,extractive distillation,pressure swing distillation,reactive-extractive distillation,and reactive-pressure swing distillation techniques were used to design and optimize the distillation process of the methanol-methyl ethyl ketone-water azeotropic system.（1）Based on the relative volatility,three commonly used extractants in industry were screened,and a triple-column extractive distillation separation process using ethylene glycol as the extractants was proposed.On the basis of this process,the potential for process intensification was explored by using the dividing wall column technology.To solve the mixed integer nonlinear programming problem in the optimization of the distillation process,a particle swarm optimization algorithm was introduced.After adopting the dividing wall column technology,the total annual cost（TAC）and CO₂emissions of the triple-column extractive distillation separation process were reduced by 3.42%and 4.78%,respectively,and the thermodynamic efficiency was increased by8.92%.（2）Based on the study of thermodynamic properties such as residual curves and distillation boundaries for the methanol-methyl ethyl ketone-water azeotropic system,two pressure swing distillation processes with different separation sequences were developed.and the particle swarm algorithm was used to optimize the process globally.Furthermore,heat integration technology was introduced to reduce the energy consumption of the process.The TAC and CO₂emissions of the optimal pressure swing distillation separation process were reduced by 28.75%and 35.27%,respectively,and the thermodynamic efficiency was increased by 54.67%.（3）Based on the property that ethylene oxide and water can undergo chemical reactions,a reactive-extractive distillation process and a reactive-pressure swing distillation process were developed,and the particle swarm optimization algorithm was used to optimize the process globally.On the basis of the reactive-extractive distillation process,a double-column reactive-extractive distillation（DCRED）separation process was proposed,which couples the chemical reaction and extractive distillation process into one distillation column.Compared with the original separation process,the equipment investment cost was reduced by 18.49%.（4）A comprehensive evaluation was conducted on the optimal process for extractive distillation,pressure swing distillation,and reactive distillation in terms of TAC,CO₂emissions and thermodynamic efficiency.The results showed that the DCRED separation process has significant advantages in terms of economic benefits,environmental benefits,and thermodynamic efficiency,which provides a certain theoretical guidance for the industrial separation of methanol-methyl ethyl ketone-water mixture.