Farm product butter could be used as an eco-friendly feedstock or raw material for making biodiesel fuel, according to the U.S.-based scientific society American Chemical Society (ACS).
ACS scientists Michael Haas and colleagues cite rising global demand for biodiesel, and the desire to expand the feedstock base, as motivating factors for their research.
The U.S. alone has committed to producing 36 billion gallons of biofuel by 2022, a major increase from the current annual production level of about 11 billion gallons. Most of that was ethanol.
Biodiesel production, now approaching 1 billion gallons annually in the U.S., is also slated to increase. As researchers seek additional and affordable feed-stocks for biodiesel production, these scientists turned to butter, 1 billion pounds of which are produced annually, ACS said.
“The study addresses the feasibility of producing quality biodiesel from butter and demonstrates the need for caution in assessing the quality of potential biodiesels via standard specification for biodiesel fuel blend stock for middle distillate fuels (ASTM D6751), particularly in the case of samples containing the esters of fatty acids 10 or fewer carbons in length,” said ACS.
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Among such lipids are palm kernel and coconut oils, abundant lipids that are being assessed globally as biodiesel feed-stocks. Could surplus, spoiled, or nonfood-grade butter be used to make biodiesel at competitive prices?
ACS said the scientists recovered the fat from a quarter-ton of butter and converted it into the fatty acid esters that constitute biodiesel. Scientists found the resulting material met all but one of the official test standards for biodiesel.
The study concluded that with further purification or by blending with biodiesel from other feed-stocks butter biodiesel could add to the supply of bio-based fuel for diesel engines.
Although annual U.S. production is considerable, slightly above 1 billion pounds (454 million kilograms, 498 million liters) of butter, demand is also substantial. Butter prices on the commodity markets are on the order of $2.00 per liter ($2.20 per kilogram).
Given the about $0.80 to $1.00 per liter retail cost of biodiesel, it is clear that food grade butter cannot be a significant feedstock for biodiesel production. However, spoilage, excessive storage, and other situations can render butter inedible and available at reduced cost. It is possible that in these cases it may be considered as a biodiesel feedstock, ACS said in a statement.
In 2008, U.S. biodiesel production has been estimated at 2.65 billion liters (2.35 million metric tons), up from 7.57 million liters (0.0067 million metric tons) in 2000. In the European Union, the world leader in biodiesel production, 2007 output was over 3.42 billion liters (3.03 million metric tons).