A novel energy-efficient extraction-assisted distillation design for isopropanol-butanol-ethanol purification for use of gasoline additive

BACKGROUND Biobutanol is considered to be a promising alternative biofuel in terms of sustainability and environmental friendliness because of its desirable properties. High purity isopropanol-butanol-ethanol (IBE) mixture can be directly used as gasoline additive. However, the purification process of IBE is hindered because of its low concentration and high energy consumption. In order to reduce energy consumption and improve the efficiency of the IBE purification process, two novel processes combining liquid-liquid extraction with extractive distillation or azeotropic distillation are proposed. Moreover, the heat integration designs of the processes are carried out to further reduce energy. These processes are compared with regard to energy, economic, environmental and exergy impact. RESULTS The results show that the energy consumption of these enhanced processes are effectively reduced compared with the original process in the literature. Among them, the thermal integrated process of liquid-liquid extraction combined with extractive distillation is the best design, which has a total annual cost of $32.656 x 10(5) and an energy consumption of 5936.94 kW. CONCLUSION Compared with the original process, this process can save 71.33% of energy consumption. (c) 2021 Society of Chemical Industry

Automated summary

Two novel processes combining liquid-liquid extraction with extractive distillation or azeotropic distillation are proposed to reduce energy consumption and improve the efficiency of IBE purification. The results show that the thermal integrated process of liquid-liquid extraction combined with extractive distillation is the best design, with significantly reduced energy consumption.