Energy potential of spent grains from brown porter style beer production

This study aimed to evaluate the energy potential of residual biomass (brewer spent grains BSG) of Brown Porter type beer malt. Analyses of calorific value, moisture, lignin content, ash content, volatile materials and fixed carbon were carried out to investigate the energy potential of BSG. For a better understanding of the thermal degradation behavior of BSG, a thermogravimetric analysis was performed and the TGA curves evidenced the degradation of lignocellulosic matter as hemicellulose and cellulose (120°C and 350°C) and lignin (350°C and 600°C). The observed moisture content measured was 12.69%. The BSG analyzed showed good potential for direct energy generation, 16.57 MJ kg, of useful calorific value when the moisture of the material is disregarded. This result is supported by the values measured for the lignin content (31.79% in dry mass) and with carbon, hydrogen, nitrogen and oxygen contents values of 44.85%, 7.06%, 3.53% and 40.70%, respectively. Another positive point is that the ash content of BSG produces less ash, 3.86%, than other biomasses as rice husks and sugarcane bagasse, which facilitates its application in the combustion process. The characterization of the grains used for the production of different types of beer is important for the best use of the residues for power generation, providing alternatives for the beer market.