Posts tagged: Scotland

Turning Whisky Waste into Energy

By , April 11, 2012 11:00 am

recycling whisky waste

Whisky is Scotland’s biggest export. Sales abroad have recently boomed: in Central and South America sales are up 49% to £214.4 million, in Taiwan they are up 45% to £70.3 million, and in Singapore up 64% to £148.5 million (source: Experts in the industry put this down to an emerging middle class in these countries who see scotch as a status symbol.

This means the whisky industry has more demand to fill, higher fuel bills and more waste to deal with. One of the purposes of engineering is to turn a negative into a positive, and this has been done in the whisky business by turning the waste into biomass and biofuels.

Two firms are so far on board, and more are sure to follow. There is Diageo the multinational alcohol conglomerate who has property in Scotland, and Celtic Renewables (from a project started at Edinburgh’s Napier University).

Both are taking the spent grains used in the whisky making process, or graff as they are known, to re-use. Diageo plan to turn the graff into biomass to use to power whisky production.

Celtic Renewables are taking the graff and pot ale (another waste product) and converting them into the fuel biobutanol using a modified acetone butanol ethanol fermentation process. The fermentation process releases carbon dioxide (unfortunately) as well as butanol, and ethanol. What is left over can be turned into animal feed. It is also feasible to take an effluent by-product and convert that into an energy product.

Celtic Renewables estimate that Scotland’s booming whisky industry produces 1.6 billion liters of pot ale a year and 500,000 tons of graff a year (source: Magazine – The Chemical Engineer, March 2012 p9). That represents a lot of waste that can be used to make energy.

Diageo hopes to drastically reduce its bills and carbon emissions. It estimates that its plant in Glenlossie can be sustainable in terms of energy. It estimates that its plant will use 30,000 tons of graff which is used in making 3.2 million gallons of whisky. It is expected to cut carbon emissions by 6,000 tons a year (ibid

Designing and building more graff and pot ale processing plants will be essential to the future profitability of the whisky industry in Scotland, as fuel prices will continue to increase and as more regulation over carbon emissions comes into effect.

The wider point is that one of the most urgent briefs for engineers in the early Twenty-first Century will be to design systems to re-use, re-purpose and recycle waste from manufacturing processes. Simply put, there is a fear that things are going to start running out, and that it is no longer enough to make a process more efficient. The new goal is to make a process sustainable. Sustainability is the new watch word for design in engineering.

In the case of whisky production, re-using the graff and pot ale is good, but this does not take account of the huge amounts of water used in making whisky or the valuable land resources given over to growing grains for distilling that could be used for food production.

1) Chemical Engineer Magazine March 2012/04/11

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