BioFuel - Membrane Units for Bioethanol Distillation
Conventional bioethanol is distilled by steam distillation. While this process is well known it consumes a substantial amount of energy and is not economically on a small scale.
Therefore, the BioFuel Technology ApS combines the CoMeTas A/S SiC membranes with more or less conventionally known pervaporation membranes in order to achieve a robust and energy efficient distillation.
A pervaporation module consists of a molecularly porous membrane permeable for ethanol mainly. The module produces ethanol vapour on the vacuum side of the semi-permeable membrane, which is subsequently condensed and re-distilled to achieve a 95 wt % ethanol. A subsequent dewatering of the ethanol produces 99 wt % ethanol.
The fermentation of 2nd generation bioethanol produces a dilute 5-10% ethanol concentration in the fermentation liquid. This concentration is smaller in comparison to conventional ethanol production, and it is therefore particularly important to benefit from an energy efficient distillation when producing 2nd generation bioethanol.
It is estimated that the BioFuel Technology ApS system of producing 2nd generation bioethanol yields an energy return of more than 6 times the energy input. This is outstanding in comparison to conventional bioethanol production, where the energy yield is of the order of 1.5 times the input.