Crispy, golden french fries are a main part of many American meals. Now, the vegetable oil they are fried in has become the main ingredient in a new alternative diesel fuel known as "biodiesel." And while french fries are known as junk food, the new biodiesel is anything but junk fuel.
The new process was developed at the U.S. Department of Energy Idaho National Engineering and Environmental Laboratory. Researchers Bob Fox and Dan Ginosar have found used french fry oil can be converted into an environmentally friendly diesel fuel faster and less expensively than current processes while producing an even higher grade fuel.
The process of converting vegetable oils or animal fats to diesel fuel is nothing new. Biodiesel fuel has been produced and tested for years as an alternative to petroleum based diesel fuel, or "petrodiesel."
Using biodiesel in place of petrodiesel offers some distinct advantages. First, the biodiesel is much more environmentally friendly. It burns cleaner and more completely, meaning less pollution. Pollutants include hydrocarbons, sulfur, carbon monoxide and particulates, which are responsible for the thick black exhaust clouds that foul the air behind some diesel-powered vehicles.
Biodiesel is also free of aromatic compounds, the substances that give fuel its "cetane" rating (diesel's equivalent of gasoline's more familiar octane rating). However, these compounds include toxic chemicals like benzene and toluene and are carcinogenic. Biodiesel actually has a better cetane rating than petrodiesel without using aromatics.
Particulates and aromatic compounds lead to the familiar, caustic odor of burned petrodiesel fuel. Biodiesel has a different, yet probably more familiar odor when it burns. It smells like fried chicken.
In fact, it smells so much like fried chicken that when the National Park
Service considered using biodiesel fuel for tour buses in the parks, it worried
that bears would chase the vehicles in the mis
Contact: Teri Ehresman
DOE/Idaho National Laboratory