Combustion characteristics and retention-emission of selenium during co-firing of torrefied biomass and its blends with high ash coal. (December 2017) - Ullah, Habib
Highlights: The combustion characteristics of HAC, PW and TPW were assessed. The kinetic study of high ash coal co-combusted with PW and TPW, were depicted. The retention-emission behavior of selenium during combustion process was studied. Se emission was decreased during co-combustion of TPW with HAC. The high affinity of selenium with fly ash particles may cause Se-retention. Abstract: The combustion characteristics, kinetic analysis and selenium retention-emission behavior during co-combustion of high ash coal (HAC) with pine wood (PW) biomass and torrefied pine wood (TPW) were investigated through a combination of thermogravimetric analysis (TGA) and laboratory-based circulating fluidized bed combustion experiment. Improved ignition behavior and thermal reactivity of HAC were observed through the addition of a suitable proportion of biomass and torrefied. During combustion of blends, higher values of relative enrichment factors in fly ash revealed the maximum content of condensing volatile selenium on fly ash particles, and depleted level in bottom ash. Selenium emission in blends decreased by the increasing ratio of both PW and TPW. Higher reductions in the total Se volatilization were found for HAC/TPW than individual HAC sample, recommending that TPW have the best potential of selenium retention. The interaction amongst selenium and fly ash particles may cause the retention of selenium.