Formation of Fine Particles from Residual Oil Combustion: Reducing Ultrafine Nuclei Through the Addition of Inorganic Sorbent

摘要

The paper gives results of an investigation of the characteristics of particulate matter emitted from residual oil combustion and the reduction of ultrafine nuclei by postflame sorbent injection, using an 82-kW-rated laboratory-scale refractory-lined combustor. Without sorbent addition, baseline measurements of the fly ash particle size distribution (PSD) and chemical composition indicate that most of the metals contained in the residual oil form ultrafine particles (approx. 0.1 micrometer diameter). These results are consistent with particle formation via mechanism of ash vaporization and subsequent particle nucleation and growth. Equilibrium calculations predict metal vaporization at flame temperatures and were used to define regions above the dew point for the major metal constituents (iron, nickel, vanadium, and zinz) where vapor-phase metal and solid-phase sorbents could interact. The addition of dispersed kaolinite powder resulted in an approximate 35% reduction in the ultrafine nuclei as determined by changes to the PSDs as well as the size-dependent chemical composition.