The Process

DBRL employs innovative processes and stringent quality measure to ensure the highest grade ethanol is produced and will be the first ethanol plant of its type built in Australia to use dry grain (Sorghum) as its feedstock.

The Process at a Glance

Ethanol is produced by fermenting sugars sourced from cereal grains and sugar cane. This in itself sounds rather simple, but in fact the process is very complex and strictly controlled under full Quality Control. The process begins by milling the feedstock - grinding the raw grain (Soghum) 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 material (called the mash) is cooled and another enzyme is added, which converts the liquid starch into fermentable sugars. This is called saccharification.

Once this process 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 13-16 percent.

This mix is then pumped from the fermentation tanks into a distillation system, which removes the alcohol from the water and the solids. This distillation gives us a liquid which is around 96 percent ethanol. The rest of the liquids and solids are called stillage, and are set aside. The 96 percent ethanol liquid is then dehydrated using a Molecular Sieve, removing virtually all the water. This gives us pure ethanol. At this stage, toxic chemicals are added to the ethanol to make it unsuitable for human consumption. This is called denaturing, and for fuel ethanol involves adding two or five percent petroleum.

After the denaturing, the ethanol is ready to be added to your vehicle as a fuel additive or alternative.

Steps in the Grain Ethanol Manufacturing Process
	Milling  The sorghum, corn or wheat first passes through hammer mills, that grind it into a fine powder called meal.
	Liquefaction The meal is then mixed with water and alpha-amylase, goes through cookers, and starch is liquefied at higher temperatures. These high temperatures reduce bacteria levels in the mash.
	Saccharification  The mash is then cooled and the secondary enzyme (gluco-amylase) added to convert the liquefied starch to fermentable sugars
	Fermentation  Yeast is added to ferment the sugars to ethanol and carbon dioxide in a batch fermentation process which lasts for up to 48 hours.
	Distillation  The fermented mash, (10% 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% stength, and the residue mash, exits as a by-product.
	Dehydration  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.
	Denaturation  Ethanol that is used for fuel is then denatured with a small amount (2-5%) of petrol, to make it unfit for human consumption.
	Co-Products  There are three main co-products created in the production of ethanol Distiller's grain Syrup Carbon-Dioxide

At full capacity, the biorefinery is expected to produce more than 90 million litres of fuel ethanol each year, using in excess of 220,000 tonnes of sorghum. One of the most important components of the DBRL business is our specialized workforce. Staff are highly-skilled with a specialized knowledge of the manufacturing processes. DBRL is dedicated to an on-going education programme for staff giving good results in quality control, commitment and motivation.