Downstream Process

DSEC's commitment on the construction of Bioethanol plants is based on a very specialized technical knowledge of the Ethanol production processes; in this article you will find a more detailed understanding about the Downstream Process.

The alcohol in the fermented mash is then concentrated by means of distillation and rectification, before the required water content of ethanol is regulated in the dewatering process. The accrued residues from distillation, the so-called stillage, is first evaporated and then dried to animal feed, the so-called DDGS. However, the production (drying) of DDGS requires a considerable amount of primary energy (e.g. fuel oil or natural gas); therefore, if feedlots are nearby, animal feed will be sold in wet condition, so called WDGS. For sugar cane and molasses the residue, so called vinasses, was returned to the fields as fertilizer- due to sustainability reasons and change in legislation, spraying of vinasses on the fields is mostly forbidden in the meantime. In the past, direct combustion of DDGS turned out to be unfeasible because of procedural difficulties and lacking efficiency (due to the high water content of the stillage).

The realisation of a biogas plant could not be achieved in large scale so far because of the enormous quantities of stillage and their high organic stress. Combination of ethanol production with biogas respectively, biomass burning results in different biorefinery concepts or so called next generation technology.

Bio-Ethanol Downstream Process

Downstream process groups:

  • Distillation
  • Rectification
  • Ethanol dewatering (molecular sieve, membranes, or entrainer distillation)
  • Decantation
  • Evaporation
  • Drying