Chemical Engineering and Processing, Vol.122, 161-171, 2017
Techno-economic assessment of extractive distillation for tert-butyl alcohol recovery in fuel additive production
Excess tert-butyl alcohol is generally used to promote the etherification reaction for production of glycerol ether. However, the difficulty in recovering this excess alcohol is caused by the presence of an azeotropic mixture of tert-butyl alcohol and water, a by-product from the etherification. This work proposes a recovery process of tertbutyl alcohol consisting of extractive distillation and conventional distillation columns. Feasible organic and ionic liquid solvents are firstly screened through such criteria as environmental concern and thermodynamic insight. Then, simulations of the extractive and distillation system for tert-butyl alcohol recovery are performed based on the suitable selected solvents, i.e., 3-octanone, hexyl acetate and 2-heptanone. From the techno-economic assessment, hexyl acetate is the most suitable solvent and the optimal configuration and operation of the process are also presented. Regarding the environmental impact indicator, hexyl acetate is also considered the most suitable solvent due to the lowest requirement of solvent.
Keywords:Extractive distillation;Tert-butyl alcohol recovery;Optimization approach;Total annual cost;Potential environmental impact