Combustion properties of upgraded alternative biomasses by washing and steam explosion for complete coal replacement in coal-designed power plant applications

To demonstrate the benefits of upgrading biomass, six samples of unique materials were combusted under pulverized fuel conditions aiming at the demonstration of complete coal replacement. These fuels were: sugarcane bagasse (SCB) (raw and steam exploded); sugarcane trash (SCT) (steam exploded and washed + steam exploded); empty fruit bunch (steam exploded and washed + steam exploded). The study shows that volatiles dominate the NOX formation, thus with a proper air staging all upgraded biofuels can be used to reduce directly NOX formation, when replacing coal. Washing reduces slagging issues by removing most of K, however, in the case of the sugarcane based biofuels, Fe still plays a crucial role in the melting/slag behavior. The combustion of raw bagasse and steam exploded bagasse formed relatively low amounts of aerosols, nevertheless enriched in NaCl and KCl, which poses a potential operational/corrosion risk when deposited on heat-exchanger surfaces. For SCT and EFB, washing is essential to reduce the aerosol formation, e.g. for EFB the submicron-particle mass was reduced by more than 90% and the fouling decreased proportionally by a factor of 10. Without washing unacceptably high slagging, fouling and corrosion potentials were observed with the steam exploded EFB. (c) 2022 Published by Elsevier Ltd.