Formation of Acid Gases from Co-firing of Coal with Raw and Torrefied Biomasses

Abstract

This work examined the emission for SO2, NOx, and CO2 gases from the combustion of pulverized coals, raw and torrefied biomasses, and 50-50 wt% blends thereof. The fuel samples chosen for this work are a high-sulfur bituminous coal (Illinois #6), a low-sulfur sub-bituminous coal (Powder River Basin), a herbaceous biomass (corn straw) and a crop-related biomass (rice husk). All fuel samples were burned in a laboratory-scale electrically-heated drop-tube furnace (DTF), operated at 1400 K, and combustion emissions were measured in the furnace effluent. Coal and biomass particles were in the ranges of 75-90 μm and 90-150 μm, respectively. Results showed beneficial synergisms for almost all blend samples that can reduce the SO2 and NOx emissions to values below those predicted by linear interpolation of the SO2 and NOx emissions of the involved neat fuels.