Waste-whiskey in the driving seat

Celtic Renewables hopes to modify unused whiskey draff into a source of fuel by converting leftover residue into biobutanol.

Scottish distillers produce around 422 million gallons of unusable pot ale and approximately 500,000 metric tonnes of draff annually, with only 10% of all whiskey being used for human consumption.

Martin Tangney, president of Celtic Renewables, believes his company has an opportunity to aid in the disposal process whilst also turning “one man’s waste into another man’s gold.”

The main benefit of producing biobutanol is its four-carbon molecular structure…

The first such effort to isolate and utilise Clostridium acetobutylicum, the product necessary in creating butanol, was by Chaim Weizmann in the early 1900’s.

However, the technique has recently generated interest after American inventor David Ramey drove across the United States, in an unmodified vehicle using only pure biobutanol.

The main benefit of producing biobutanol is its four-carbon molecular structure, which offers 25% more energy by volume than ethanol. Tangey has also suggested that the bio-product is capable of burning directly in an internal combustion engine but will most likely be blended with gasoline.

Additionally, the biobutanol proposed by Celtic Renewables has the potential to be mixed at the refinery, rather than having to make further modifications in a separate location and also offers the advantage of not requiring additional land and crops as it is produced solely from waste.

The process, currently in the early development stages, will also be capable of producing two further products: bioacetone - for use in the paints and plastics sectors and solid waste as a source of animal feed.

If the concept proves viable, it is set to help reduce Scotland’s waste stream and has already generated some interest as the group has received around £750,000 in government-based funding to pursue the project.