Vegetable oil refining

Vegetable oil refining is a process to transform vegetable oil into fuel by hydrocracking or hydrogenation. Hydrocracking breaks big molecules into smaller ones using hydrogen while hydrogenation adds hydrogen to molecules. These methods can be used for production of gasoline, diesel, propane, and other chemical feedstock. Diesel fuel produced from these sources is known as green diesel or renewable diesel.

Feedstock

The majority of plant and animal oils are vegetable oils which are triglycerides—suitable for refining. Refinery feedstock includes canola, algae, jatropha, salicornia, palm oil, and tallow. One type of algae, Botryococcus braunii produces a different type of oil, known as a triterpene, which is transformed into alkanes by a different process.

Comparison to biodiesel

Based on its feedstock green diesel could be classified as biodiesel; however, based on the processing technology and chemical formula green diesel and biodiesel are different products. The chemical reaction commonly used to produce biodiesel is known as transesterification. Vegetable oil and alcohol are reacted, producing esters, or biodiesel, and the coproduct, glycerol.