High-temperature honeycomb molecular sieve catalyst for efficient and safe NOx removal in gas-fired internal combustion engine

To address the challenges of efficient and ‌safe denitrification under actual flue gas conditions of internal combustion engine, high-temperature SCR molecular sieve catalyst were prepared and evaluated both in laboratory scale and industrial scale. A comprehensive characterization via TG, XRD, N₂ adsorption-desorption, SEM, and TEM confirmed the robust thermal stability of the molecular sieves catalyst. The molecular sieve catalyst system was commissioned in a 4275 kW distributed natural gas internal combustion engine demonstration facility and successfully passed the 72 h trial running, achieving with over 94 % NO x conversion efficiency‌ and less than 40 mg/m 3 outlet NO x concentration at a temperature range of ‌440–525 °C. Compared to conventional V-based catalyst, the molecular sieve catalyst not only achieved additional reductions of 2 kg/h NO x and 38 kg/h CO 2 emissions, along with a nearly 2 % improvement in internal combustion engine efficiency, but also effectively mitigated the risk of system shutdown caused by low cylinder temperatures in exhaust gas purification systems, being considered as a promising catalyst for high-temperature applications, including gas-fired, hydrogen/ammonia-fueled, and biogas internal combustion engines.