Conceptual design of clean separation of ternary mixture of acetone-tetrahydrofuran-water
Based on the thermodynamics analysis of the mixture of acetone, tetrahydrofuran (THF) and water, the conceptual design of a clean separation process for this mixture was developed. Extractive distillation was used to separate water from the other two components. Different extractive solvents were compared through simulation with Aspen plus and it was found that triethylene glycol (TEG) was a highly selective and energy saving solvent.The extracted water could be separated from extractive solvent by ordinary distillation.The simulation results from Aspen plus showed that the separation of THF and acetone could be achieved by azeotropic distillation using cyclohexane or carbon bisulfide (CS_2) as azeotropic solvent according to different end requirements. When CS_2 was used as azeotropic solvent, high purity THF could be obtained while accompanied by with high energy cost due to low CS_2 content in the binary azeotropic mixture of CS_2 and acetone.If cyclohexane was used as azeotropic solvent, a great deal of energy could be saved at the sacrifice of reduced purity THF.The separation of an azeotropic solvent and acetone could be realized through a liquid-liquid extraction process using water as extractive solvent. No waste water and other waste liquid were produced during the whole separation process thanks to the recycling of extractive solvent and azeotropic solvent.Therefore the separation process developed here could be considered as a clean separation process.