Reduction of ammonia emissions from industrial furnace process gases using stationary catalytic systems

The paper presents research into the possibility of reducing emissions of ammonia, which is the main component of post-process gases emitted from thermo-chemical treatment furnaces, particularly in the nitriding and carbonitriding of steel. The research involved testing the validity of system consisting of an Ammonia Slip Catalyst and a Selective Catalytic Reduction Reactor (SCR) for the neutralization of dissociated ammonia and the secondary formation and reduction of nitrogen oxide. The novelty of the methodology lies in adapting catalytic technologies to metallurgical gas nitriding processes, where traditional emission control systems are not commonly used. The results of the study show that the operating temperature influences the degree of reduction of ammonia, the chemical composition of the catalytic bed, the temperature and duration of the nitriding process, the degree of saturation of the treatment chamber with ammonia, the temperatures of the post-process gases and the velocity and intensity of the post-process gases fed to the ASC reactor. The results obtained provide insight into the positive rationale for applying this technology to industrial treatment furnace solutions. The results demonstrate that, with optimized parameters, the combined ASC + SCR system can reduce NH3 and NO emissions to below 5 ppm, achieving over 95 % conversion efficiency and high selectivity toward environmentally benign end products (N2 and H2O). The findings confirm the feasibility and effectiveness of catalytic emission control in thermo-chemical treatment furnaces. A procedure scheme and main guidelines for the realization of NH3 and NO neutralization from the post-process gases of thermo-chemical treatment furnaces were prepared.