Synergistic capture mechanisms for alkali and sulfur species from combustion

This report presents work done on a laboratory combustor in an attempt to identify mechanisms that govern the simultaneous capture of alkali and sulfur species using sorbent injection techniques. The mechanisms of capture fall into two broad categories i.e. Physical transport of alkali species (in vapor or condensed phase) to the sorbent surface and surface reaction between the alkali species and the sorbents. Water solubility, though not specific, has been used to get an indication of relative significance of these two broad mechanisms. It is assumed that the physically adsorbed alkali species on sorbents are predominantly water soluble while the chemically reacted alkali content is predominantly water insoluble. In order to infer possible dominant mechanisms, specific parameters has been varied during experimentation. Such parameters include, speciation, particle time-temperature history, and furnace burning conditions