Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl (methyl, ethyl, or propyl) esters. Biodiesel is typically made by chemically reacting lipids (e.g., vegetable oil, soybean oil, animal fat (tallow)) with an alcohol producing fatty acid esters. Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone, or blended with petrodiesel in any proportions. Biodiesel blends can also be used as heating oil.
What Is Biodiesel:
Biodiesel is a diesel-like fuel derived from vegetable oil or other renewable resources. It can be made from soy or canola oil, waste cooking oil, and even animal fats. Biodiesel is made by combining the vegetable oil with alcohol [usually methanol but occasionally ethanol] in the presence of a catalyst through a process called transeterification.
Biodiesel derived from waste cooking oil is arguably the greenest liquid fuel available because the primary ingredient is a post-consumer waste product.