Oxidation of Mercury under Ultraviolet (UV) Irradiation

Oxidation of mercury under ultraviolet (UV) irradiation was carried out in a reaction chamber using both simulated and real flue gases from pilot-scale combustors burning coal. The gases examined included SO2, CO, CO2, NO, CH4, O2, water vapor, alcohol vapor, and their mixtures. The temperature of the reaction chamber was 37.8 °C (100 °F) and 137.8 °C (280 °F). A 10 W low-pressure UV light bulb was placed in the center of the reactor to provide the irradiation, with the main UV irradiation band at 253.7 nm. In addition to the simulated flue gas tests, four slipstream tests were conducted with flue gas diverted from the vertical combustor of CanmetENERGY, burning Saskatchewan lignite, and also with the mini-circulating fluidized-bed combustor (CFBC) of CanmetENERGY, burning Powder River Basin coal. The results showed that oxidation of mercury by 253.7 nm UV irradiation occurred in both synthetic and real flue gas environments, with levels of up to 65.5% of the total mercury being oxidized. The temperature ...