DBRL employs innovative processes and stringent quality measure to ensure the highest grade ethanol is produced. Ethanol is produced by fermenting sugars sourced from grain. This in itself sounds rather simple, but the process involves complex steps and is strictly controlled under full Quality Control.
The ethanol production process begins with the receipt of sorghum grain which is ground into a fine powder. The powder is mixed with water and enzymes to begin the process of breaking down the starch in the grains into glucose molecules.
Once the starch has been converted, yeast is introduced into the process. In an anaerobic environment, yeast ferment (i.e. metabolize) glucose into ethanol. The ethanol is then distilled from the fermentation broth, called beer, and is purified into nearly 100% pure ethanol.
The final product is then denatured with 1.5% ULP and is then shipped to petrol blending stations.
The remaining product once the ethanol has been distilled away is called stillage. The stillage is dehydrated down to a moisture content of approximately 68% for Wet Distiller’s Grain, and 11% for Dry. These form high protein, high energy animal feeds which are sold to nearby beef and dairy feedlots.
Steps in the Grain Ethanol Manufacturing Process
The process begins by milling the feedstock – grinding the raw grain (Sorghum) into a fine powder called meal. The meal is then mixed with water and an enzyme and heated to turn the starch in the meal into a liquid. The sorghum first passes through hammer mills, that grind it into a fine powder called meal.
Meal is then mixed with water and the enzyme alpha-amylase, goes through cookers, and the starch is liquefied at higher temperatures. These high temperatures reduce bacteria levels in the mash.
The mash is then cooled and the secondary enzyme (gluco-amylase) added to convert the liquefied starch to fermentable sugars. The material (called the mash) is cooled and another enzyme is added, which converts the liquid starch into fermentable sugars. This is called saccharification.
Once saccharification is complete, yeast is added and the mash is placed into a series of fermenters, which assist the yeast in converting the sugars into ethanol. This usually takes around 48 hours, and produces a mix of liquids and solids with an alcohol content of around 11-14 percent.
The fermented mash, (11-14% alcohol), the non-fermentable solids from the grain, and the yeast cells are pumped to the distillation system where the alcohol is distilled off. The alcohol leaves at 96% strength, and the residue mash exits to be made into animal nutrition products.
The alcohol then passes through a molecular sieve to remove the remaining water from the ethanol. The alcohol product at this stage is approximately 99.8% purity.
Ethanol that is used for fuel is then denatured with a small amount (2-5%) of petrol, to make it unfit for human consumption. After the denaturing, the ethanol is ready to be added to your vehicle as a fuel additive or alternative.