into the slag to form oxides or silicates, and the silicate content in the ash was less
when using bio-briquettes.
Emissions of nitrogen oxides, sulfur dioxide, and carbon dioxide decreased with
increases in biomass in the briquettes, while emissions of carbon monoxide and
hydrogen sulfide increased.
The results for NOx and SO2 are consistent with what one would expect with
increasing biomass addition. However, the results of CO2, CO, and SO2 simply indicate
an inadequate amount of air was not introduced to fully combust the fuel. Biomass
burns more rapidly than coal so burning a blend of coal and biomass will
initially require more air than burning coal alone.
The results demonstrated that the chemical composition of ash from the combustion
of coal with starch was similar to the composition of the BB ash. The main
chemical components in the ash were SiO2 and Al2O3 (Table 4). The actual chemical
composition is largely dependent on the source and type of biomass and the type of
boiler.