Since the minimum-boiling azeotropes of C2-C8 alcohols with water and high-water content(up to 95％(mass))in the Fischer-Tropsch aqueous by-products,the separation is energy-intensive and challenging.The energy-saving strategy for the complete separation of the Fischer-Tropsch aqueous by-products has received massive attention in recent decades.In this study,a stripper-sidestream decanter process is pro-posed by exploiting homogeneous azeotropes(C2-C3 alcohols-water)and heterogeneous azeotropes(C4-C8 alcohols-water).The introduction of the stripping column for pre-dehydration avoids the re-vaporization of the mixture,and energy carried by the overhead vapor is conserved instead of being removed in a condenser.The precise fraction cutting of C1-C3 alcohol-water mixture,C4-C8 alcohols,and water is realized by the sidestream distillation column.The C4-C8 alcohols rich mixture withdrawn from the sidestream flows into the decanter to break the distillation boundary,where the organic phase returns to the sidestream distillation column to obtain the dehydrated C4-C8 alcohols,and the aqueous phase enters the stripping column.Steady-state optimization based on total annual cost(TAC)minimiza-tion shows that the stripper-sidestream decanter process reduces TAC by 17.00％and saves energy by 21.27％compared with the conventional three-column distillation process.Further,a control structure of the process is established,and dynamic simulations show that the control structure combining a dif-ferential controller with a low-selector exhibits robust control.This study provides a novel design scheme and deepens the insights into the efficient separation of aqueous by-products of the Fischer-Tropsch synthesis.

Renren Zhang;Yang Huang;Kaitian Zheng;Chunjian Xu

School of Chemical Engineering and Technology,State Key Laboratory of Chemical Engineering,Chemical Engineering Research Center,Tianjin University,Tianjin 300072,China

中国化学工程学报（英文版）

[1]Renren Zhang;Yang Huang;Kaitian Zheng;Chunjian Xu-.Design and control of fraction cutting for the separation of mixed alcohols from the Fischer-Tropsch aqueous by-products)[J].中国化学工程学报（英文版）,2022(10):143-154

azeotropes,stripper,sidestream,decanter,minimiza

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