The Use of Brewer's Spent Grain after Beer Production for Energy Purposes

The aim of this study was to assess the possibilities to use brewer's spent grains (BSGs) left over from beer production for energy purposes, and to determine its calorific value and chemical composition. The research materials were samples of wet spent grain from a brewery in Poland. Three samples, that are different in ingredient composition, were examined. The examined samples of BSGs were characterised by humidity that is typical for this product (approx. 77-80%). Convective drying of the spent grain contributed to a reduction in the water content in the biomass to below 10%. Samples of dry spent grain that were examined contained a similar amount of ash (3.8-4.1% d.m.) and organic matter (91.0-91.9% d.m.). All the examined spent grain samples demonstrated similar volatile matter content-approx. 77.8-78.7% d.m. and calorific value-approx. 15.6-15.9 MJ/kg. The estimated calorific value for wet samples (approx. 1.4-2.0 MJ/kg) indicated that it is necessary to lower water content in the biomass in order to improve its energy properties.