Abstract Number: 191 Working Group: Combustion-Generated Aerosols: the Desirable and Undesirable
Abstract As a promised CO2 capture technology, pressurized oxy-fuel combustion has unrevealed characteristics on particle matter emission. Hence, a 10kWth lab-scale pressurized oxy-fuel fluidized bed combustor (POFBC) with continuous fuel feeding system and electrical low pressure impactor (ELPI) has been established and operated at 0.3 and 0.5MPa. This work focus on the alkali and alkali earth metals (AAEM) in particle matter formed under air and O2/CO2 atmosphere at elevated pressures. It is found that Na shows obvious gasification in all experimental conditions while K shows an identifiable enrichment in submicron particles only when the temperature and pressure reach the threshold. As a result, the climax of particle concentration of Na is located near 0.1μm compared with K whose climax is located near 1μm. The increasing pressure promotes the release of both Na and K from the coal by enhancing the char temperature. Mg and Na seem to share a consistent trend at high pressure, indicating Mg is released to the gas phase in pressured combustion. The content of Ca increases gradually with the increased particle diameter due to the fragment of ash during the combustion process to some extent.