Multiplicities in dividing wall distillation columns in the purification of bioethanol: energy considerations

Abstract

In this paper, we present results about the energy requirements in the reboilers of an extractive dividing wall distillation column and a thermally coupled distillation sequence with a side rectifier for bioethanol dehydration using glycerol as entrainer, and the study generates the appearance of multiple steady states. During the energy optimization of the dividing wall distillation column, using glycerol as entrainer, the recycle streams were varied until the energy consumption in the reboiler was obtained and the multiple steady states can present a difference of up to 400%. This finding is important since we are interested in detecting the optimal energy consumption in order to reduce the environmental impact caused by the usage and production of energy from petroleum. This information is being used in a current pilot plant in order to detect the optimal operation conditions to dehydrate bioethanol.