Creating Biodiesel

The process of producing biodiesel allows us to use a variety of otherwise discarded waste products to make a clean alternative to conventional diesel fuel. Biodiesel can be made from new or used vegetable oils and animal fats, which are nontoxic, biodegradable, and renewable. Fats and oils are chemically reacted with an alcohol and a catalyst to produce chemical compounds known as fatty acid methyl esters. Biodiesel is the name given to these esters when they are intended for use as fuel. Glycerin is produced as a co-product, which is also repurposed for use in pharmaceuticals, cosmetics and other products.

Biodiesel can be produced using a variety of esterification technologies. The oils and fats are filtered and preprocessed to remove water and contaminants. If free fatty acids are present, they can be removed or transformed into biodiesel using special pretreatment technologies. The pretreated oils and fats are then mixed with an alcohol (usually methanol) and a catalyst (usually sodium hydroxide or potassium hydroxide). The oil molecules (triglycerides) are broken apart and reformed into methyl esters and glycerin, which are then separated from each other and purified. Roughly speaking, 100 pounds of oil or fat are reacted with 10 pounds of a short-chain alcohol (usually methanol) with a catalyst to form 100 pounds of biodiesel and 10 pounds of glycerin.

Schematic of biodiesel production path.

REV's professionally produced biodiesel fuels meet the rigorous standards of ASTM (American Society for Testing and Materials) International, providing, powerful and safe biodiesel for commercial and consumer vehicles. REV biodiesel focuses on the use of fat or oil feedstock, including recycled cooking grease, which reduces the use of feedstock derived from primary human resources such as corn or soy. Enough recycled restaurant grease and other feedstocks are readily available in the United States to produce about 1.7 billion gallons of biodiesel per year (under policies designed to encourage biodiesel use). This represents roughly 5% of on-road diesel used in the United States.