Ethanol Production Process


Vireol will use proven KATZEN (www.katzen.com) process technology for the Project.

The process uses the established dry milling approach followed by batch fermentation to convert cereal grain into high purity ethanol.  KATZEN have engineered numerous ethanol plants around the world and can be considered to be one of the current technology world leaders.

The ethanol plant will convert the starch from the grain to approximately 570,000 litres per day of ethanol, and concentrate the remaining grain into a high fibre, high protein animal feed.  Wheat will be the key raw material but other cereals, such as rye, barley and maize, could also be utilised.

Illustration of the Ethanol Production Process

Diagram of the ethanol production process_medium

The key steps associated with the transformation of grain into ethanol are summarised below:

  • the cereal is delivered to site via truck where it is analysed, unloaded and pre-cleaned if necessary, prior to storage;
  • the grain is milled to a defined particle size and mixed with steam, fresh and recycled water, and enzymes to liquefy the starch contained in the grain particles (a process know as 'liquefaction'); 
  • Further enzymes are added and the starch in the liquefied grain particles converts to glucose and higher sugars (a process known as 'saccharification');
  • the saccharified substrate goes through a fermentation process during which the fermentable sugars are converted to alcohol (Ethanol) and carbon dioxide by yeast in one of a number of batch fermenters.  The carbon dioxide is drawn off from the fermentation vessels, captured and can be directed to a liquefaction plant for subsequent commercial use.  The remaining mixture in the fermentation vessels is called 'Beer Mash';
  • the beer mash is distilled to produce a more concentrated ethanol and a slurry ('stillage') containing water and the remaining solids;
  • the ethanol stream is further dehydrated in a set of molecular sieves to produce finished ethanol product which is pumped off site for storage, blending and delivery;
  • the stillage is processed and eventually dried into a product called Dried Distillers Grain and Solubles (DDGS), which is used as a high fibre, high protein, GM-free animal feed.  The DDGS will be removed from site by conveyor to an adjacent dedicated storage warehouse operated by our DDGS offtaker.