Ammonium Chloride\nPowder Feeding for the Simultaneous\nReduction of NOx and Oxidation of Hg<sup>0</sup> in the SCR Process

This study was dedicated to enhancing coal-fired power\nplant (CFPP)\nsustainability by enhancing the Hg<sup>0</sup> oxidation efficiency\nin the selective catalytic reduction (SCR) process by injecting powder\nNH<sub>4</sub>Cl. It is relatively harmless, energy-saving, and easy\nto handle, can be easily sublimated to NH<sub>3</sub> and HCl at the\nSCR-operating temperature, and can simultaneously reduce NO and oxidize\nHg<sup>0</sup>. In the honeycomb-type H1.5-VWT, the Hg<sup>0</sup> oxidation efficiencies were 58.7 and 74.6% when HCl was supplied\nat 10 and 30 ppm, respectively, by powdered NH<sub>4</sub>Cl feeding.\nShell mass balance-based models were developed to associate the performances\nof the powdered and honeycomb catalysts, and the surface area-normalized\nkinetic rates were evaluated. Ultimately, the NO reduction and Hg<sup>0</sup> oxidation efficiencies could be predicted based on the vanadia\ncontent, honeycomb size, and gas composition. Solid-phase NH<sub>4</sub>Cl injection can be conveniently applied in the SCR process and is\nexpected to improve the sustainability of CFPPs.