Our bio-refinery processes all our raw material, being mainly corn, in a number of added value products as shown in the flow chart below.
The process uses the starch (effectively sugar) that is available in the grains. The sugars from the grain are eventually converted into liquid energy: alcohol. The protein in the grain is preserved to the maximum and supplemented with valuable yeast proteins. It becomes a nutricious rich animal feed. All the important steps are shown in the flow diagram and explained in more detail below.
As starch cannot ferment directly, preparatory steps are required. Corn, for example, is first milled, mixed with water, cooked and manipulated by special enzymes. The mash created after cooling down goes into a fermenter where yeast and other enzymes are added. During fermentation, yeast transforms sugars into ethanol and CO2.
The fermentation cycle will last from 50 to 60 hours at a temperature of 30 to 32°C, and the resulting product, called ‘beer’, has a strength of 16-18 % alcohol by volume.
Following is the distillation process to concentrate and purify the alcohol stream.
The last phase in the process is dehydration where the remaining water is removed to produce ethanol containing less than 0.3 % water — ‘absolute’ or ‘anhydrous’ alcohol.
The whole stillage (beer stripped of alcohol) is further processed in different steps to animal feed. This involves a centrifugation step, separating the fibre fraction (wet distillers’ grains) from the clarified liquid (thin stillage). Thin stillage is evaporated to a syrup (condensed distillers’ solubles). Wet distillers’ grains and condensed distillers’ solubles are then mixed and dried to form DDGS (dried distillers’ grains and solubles).
During evaporation of the thin stillage, corn oil is separated after pre-treatment using a centrifuge.