When sugar is fermented by yeast, carbon dioxide (CO2) is evolved as the yeast respires. The North British Distillery is the only distillery to collect, purify and sell liquid CO2.
The distillery is capable of producing approx. 20,000 tonnes of C02 each year. C02 gas can be liquefied by cooling it under high pressure. C02 gas is collected and compressed to 21 bar by a compressor. The pressurised gas is then purified and dried by passing it through a number of vessels.
The purified gas is condensed into a liquid by cooling it to about -25°C using a refrigeration compressor
The liquefied CO2 is stored in two large tanks, each with a capacity of 150 tonnes. The CO2 is used in a number of applications such as carbonating beer, soft drinks and mineral water and sold to tomato growers for use in their greenhouses.