Ash Deposition Modeling Incorporating Mineral Matter Transformations and Pseudo-steady Deposit Build-up Applied to Coal Biomass Co-firing

摘要

Reaction Engineering International (REI) and Nalco Mobotec have recently teamed to quantitatively evaluate ash behavior when firing biomass in coal-fired boilers. The Nalco Mobotec System can enable boilers to switch to biomass co-firing or burn up to 100 percent biomass with no change in boiler load capacity, while meeting strict emission control requirements. As biomass often contains inorganic compounds that can impact deposition/slagging/fouling/corrosion, Nalco Mobotec has taken care to consider potential ash impacts, offering chemical treatments that have successfully reduced deposition rates and reduced the tenacity of the deposits that do form. In an effort to mitigate risk and to provide guidance related to the magnitude, location, and sintering extent of deposition, REI has worked with Nalco Mobotec to complement their in-house modeling efforts with its unique tools and expertise in this area. Results of CFD-based modeling efforts incorporating REI's Mineral Matter Transformation and Deposit Build-up Model quantitatively illustrated the impact of various pelletized biomass fuels on deposition behavior and fireside corrosion indicating that certain fuel mixtures can be fired without significant increase in deposition rate or deposit sintering extent, and a decrease in corrosion rate.