Process converts unloved brewery waste into high-value charcoal
According to Queen's University Belfast, breweries in the European Union dispose of about 3.4 million tons (3.084 million tonnes) of spent barley grain every year. That could be about to change, though, as scientists at the university have created a method of converting that waste into useful charcoal.
Led by Dr. Ahmed Osman, the researchers devised a process that begins with the grain getting dried out. A two-stage chemical and heat treatment follows, which utilizes phosphoric acid and then a potassium hydroxide wash – both chemicals are quite inexpensive.
What's left behind is activated charcoal, which could find use in applications such as heating fuel in homes, barbecue briquettes, or water filters. In lab tests, 1 kg (2.2 lb) of grain was sufficient to create enough carbon to cover "100 football pitches."
Ultimately, it is hoped that the technology could not only help keep spent grain from going to waste, but that it could also boost the local economy of regions where breweries are located.
"Liquid forms of carbon are normally shipped to the UK from the Middle East, and solid biocarbon, in the form of wood pellets is shipped from the US and elsewhere," says Osman. "Using this new technique, we can utilize more locally-produced resources, reduce emissions linked with the agriculture sector, and we are also creating a high-value product."
The research is described in a paper that was recently published in the Journal of Chemical Technology and Biotechnology.
Source: Queen's University Belfast