Ethanol from Raw Materials Containing Starch,
also Obtaining Protein
In order to recover ethanol from raw materials containing starch, such as wheat, rye, barley, maize etc., the industry is now increasingly using the so-called wet process. Unlike the dry process, this process is also suitable for extracting valuable protein in addition to the ethanol.
Separators and decanters from GEA Westfalia Separator play central roles in this task. A significant element here is the patented 3-phase technology for combining washing, classification and concentration of the starch slurry produced in just one process step. The following comments refer specially to the process for wheat.
Integrated process line from GEA Westfalia Separator for obtaining ethanol from raw materials containing starch by the wet process with protein also being obtained, using the example of wheat
Unlike the dry process, the wet process allows protein to be obtained as well as ethanol and the feed DDGS (dry distiller‘s grain with solubles).
Hot water is added to freshly milled grain which is intensively mixed to form a slurry. This slurry is then routed to a disintegrator by an eccentric screw pump, the mechanical forces of which cause the gluten particles to aggregate, i.e. combine. The shear forces arising in this process rupture the gluten / starch bond – a key step in achieving end products in large quantities and good quality whilst simultaneously consuming little water.
Patented 3-phase technology
Only now is the prepared slurry routed to the key process step: the grain slurry is passed to the decanter via a buffer tank which works with patented 3-phase technology and accordingly combines three process stages: washing, classification and concentration.
This technology developed by GEA Westfalia Separator allows separation into starch and other constituents of flour directly in the first process stage. A-starch and gluten are extracted separately and processed into end products whilst pentosane and B-starch pass into ethanol production. The following process steps for obtaining ethanol are largely identical to those of the dry process.