Ethanol distillation process

A process arrangement for distilling fuel grade ethanol includes a fermentation portion, a distillation portion, a condensation and dehydration portion, a separation and drying portion and an evaporation portion. The fermentation portion produces beer. The distillation portion, the condensation and dehydration portion and the separation and drying portion receives beer from the fermentation portion and produces hot ethanol vapor and thin stillage. In the evaporation portion, a set of first effect evaporators which are heated either by plant steam or hot ethanol vapor, concentrate thin stillage into mid stillage while producing first effect steam. The first effect steam from the first effect evaporators provides heat to a set of second effect evaporators which concentrate the mid stillage into a syrup for further drying. The second effect evaporators produce second effect steam which is used to heat the distillation portion of the process arrangement. The multiple evaporators of the first and second effects of the evaporation portion can be selectively taken off-line for maintenance while the evaporation portion and the remainder of the process arrangement continue to operate at full capacity.