Experimental study of homogeneous Hg oxidation in air and oxy-simulated flue gas

This study investigated the effects of Cl-2, SO2, and NO on the mercury (Hg) speciation during oxy-combustion and compared it with the Hg speciation in air-simulated flue gas with Cl-2. Experiments were conducted in a bench-scale device at 200 degrees C. The results of Hg oxidation in an N-2 and CO2 atmosphere with Cl-2 showed that CO2 indirectly restrained Hg oxidation. Oxy-simulated flue gas promoted Hg oxidation more than air-simulated flue gas promoted that, because the oxygen in oxy-simulated flue gas indirectly promoted Hg oxidation using Cl-2. The percentage of Hg oxidized in both oxy-simulated flue gas and air-simulated flue gas with NO decreased as the concentration of Cl-2 increased because NO restrained Hg oxidation with Cl-2 through the elimination of the O and ClO radicals. SO2 inhibited Hg oxidation with Cl-2 by consuming the O radicals. Moreover, when both NO and SO2 were present in oxy-simulated flue gas with Cl-2, the effect of SO2 on Hg oxidation was related to the NO concentration. (C) 2018 Energy Institute. Published by Elsevier Ltd. All rights reserved.