Effects of SCR catalyst breakage on mercury emission properties in coal-fired power plant: field testing and laboratory evaluation

Field testing toward mercury emission properties was conducted at a 300 MW coal-fired power station. Selective catalytic reduction (SCR) was found to reduce Hg content in flue gas significantly through catalyst breakage during the commercial testing in a 300 MW coal-fired power station. Field testing results indicate that the total mercury concentration in flue gas at electrostatic precipitator (ESP) inlet and ESP outlet increase due to SCR catalyst breakage. Correspondingly, mercury content in fly ash decrease and mercury content in gypsum increase. The evolution in laboratory confirmed the Hg0 oxidation capability of commercial SCR catalyst. Catalyst breakage leads to space velocity increasing, so that the lower Hg0 oxidation rates caused the mercury transformation change in flue gas and solid byproducts.