Co-combustion of brewer's spent grains and Illinois No. 6 coal: Impact of blend ratio on pyrolysis and oxidation behavior

Co-combustion of locally available biomass in existing coal-fired power plants is an attractive option to increase the share of renewable fuels in the energy market with minimal capital investment. Utilizing existing coal-fired combustion equipment for blends requires knowledge of pyrolysis and combustion characteristics. This study presents thermal evolution profiles (decomposition rates, apparent activation energies and devolatilized compounds) of coal-biomass blends to probe the effect of blend ratios on pyrolysis and combustion behavior. The global rate of pyrolysis of Illinois No. 6 coal and brewer's spent grains (BSG) is a function of fuel composition, though analysis of evolved gases suggests the presence of both potential additive and synergistic interactions on a molecular level. For oxidation, a rapid decrease in peak conversion rate is seen as the percentage of BSG increases from 0% to 20%, becoming less pronounced as the percentage of BSG increases above 20%. (C) 2014 Elsevier B.V. All rights reserved.