Ammonium Chloride Powder Feeding for the Simultaneous Reduction of NOx and Oxidation of Hg0 in the SCR Process

• Published in: Industrial & engineering chemistry research 2024-10, Vol.63 (41), p.17521-17531
• Main Authors: Park, Jung Ho, Kim, Moon Hyeon, Hong, Yongseok
• Format: Article
• Language: English
• Subjects: Kinetics, Catalysis, and Reaction Engineering
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.4c02674

This study was dedicated to enhancing coal-fired power plant (CFPP) sustainability by enhancing the Hg0 oxidation efficiency in the selective catalytic reduction (SCR) process by injecting powder NH4Cl. It is relatively harmless, energy-saving, and easy to handle, can be easily sublimated to NH3 and HCl at the SCR-operating temperature, and can simultaneously reduce NO and oxidize Hg0. In the honeycomb-type H1.5-VWT, the Hg0 oxidation efficiencies were 58.7 and 74.6% when HCl was supplied at 10 and 30 ppm, respectively, by powdered NH4Cl feeding. Shell mass balance-based models were developed to associate the performances of the powdered and honeycomb catalysts, and the surface area-normalized kinetic rates were evaluated. Ultimately, the NO reduction and Hg0 oxidation efficiencies could be predicted based on the vanadia content, honeycomb size, and gas composition. Solid-phase NH4Cl injection can be conveniently applied in the SCR process and is expected to improve the sustainability of CFPPs.