Whisky byproducts serve as biobutanol feedstock in Scotland

By Erin Voegele | February 03, 2012

Scotland-based Edinburgh Napier University’s Biofuels Research Centre has spun out a new company that focuses on converting waste products derived from whisky production into biobutanol and other renewable chemicals. The new company, Celtic Renewables Ltd., officially launched Jan. 25.

According to information released by the university, Celtic Renewables is working with Scottish Enterprise to produce the fuel on an industrial scale. The fermentation process uses two main byproducts of whisky production as feedstock, including “pot ale,” which is the liquid from the copper stills, and “draff,” which is the spent grains. Each year Scotland’s £4 billion ($6.34 billion) malt whisky industry produces approximately 1.6 billion liters (423 million gallons) of pot ale and 500,000 metric tons of draff.

“The Scottish malt whisky industry is a ripe resource for developing biobutanol,” said Professor Martin Tangney, founder of Celtic Renewables and Director of the Biofuel Research Centre. “The pot ale and draff could be converted into biofuel as a direct substitute for fossil-derived fuel, which would reduce oil consumption and C02 emissions while also providing energy security—particularly in the rural and remote homelands of the whisky industry. The launch of Celtic Renewables is a very exciting development and there is huge potential for applying our process on a global scale.”

The initial research project received £267,000 in financial support from Scottish Enterprise’s Proof of Concept Programme. Celtic Renewables has received £70,000 from Scottish Enterprise SMART, a grant to assist technology scale-up and commercial feasibility activities.

While Biorefining Magazine was unable to reach a representative of Celtic Renewables, the company’s website provides a description of the technology. According to the company, it is innovatively redeveloping a defunct fermentation technology that has already been proven on a global scale to convert pot ale and draff into renewable products such as biobutanol. The company also noted that the whisky byproducts can also be processed into acetone and ethanol.

On its website, Celtic Renewables stated that its process is based on the ABE Fermentation Process, which was invented during the run-up to World War I. The technology was used for decades to produce solvents, said the company, and was one of the largest biological industries in the world until the 1960s, when it was unable to compete with the petrochemical industry. Celtic Renewables’ revamped technology mixes draff and pot ale and ferments them to produce a broth. The fermentation process results in a mix of gases that is primarily composed of hydrogen. The resulting broth is distilled to produce butanol, acetone and ethanol. According to Celtic Renewables, the remaining solid material can be dried and used as animal feed.