Homogeneous Mercury Oxidation under Simulated Flue Gas of Oxy-coal Combustion

Abstract

This study investigated the effects of oxy-coal combustion on Hg-oxidation by HCl using simulated flue gas. Experiments were conducted with different carrier gases that one might find in oxy-coal combustion and conventional coal combustion. The extents of Hg-oxidation in pure CO2, pure N2 and air were also studied for comparison. Our experimental results demonstrated that CO2 weakly assisted Hg-oxidation by HCl; however, its significance was outweighed by the presence of O2. For all carrier gases, the presence of NO or H2O inhibited Hg-oxidation. The inhibitory effects strongly depended on concentrations of NO, but not moisture content. The synergistic inhibitory effects were shown when both NO and H2O were present together. The extents of Hg-oxidation were not significantly different for O2-N2, O2-N2-CO2 and O2-CO2 gas mixtures for all conditions investigated in this study.