Chenhui Hu,Kaimin Du,Zuoxi Zhuo,Chunhong Liu,Hongbing Lv,Wanjue Wang
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.
To elucidate how CeO2 additives enhance the activity and stability of Cu-SSZ-13 SCR catalysts, we investigated two CeO2/Cu-SSZ-13 composite catalysts with Cu loadings of 1.0 and 2.5 wt %. These catalysts were characterized using an array of techniques, including XRD, SEM, TEM, NMR, H2-TPR, NH3-TPD, DRIFTS, DFT and SCR reactions under both steady-state and transient kinetic analysis conditions. Our findings demonstrate that CeO2 promotes low-temperature SCR by forming exchanged, isolated Ce-ions, which enhance Cu-ion coupling efficiency. External surface CeO2 particles can convert NO + O2 to surface nitrates, but these species primarily act as spectators below ∼250 °C, and do not contribute to the enhancement of low-temperature SCR activity. In contrast, these surface CeO2 particles can synergizes with Brønsted acid sites (BAS) to elevate high-temperature SCR activity. Furthermore, hydrothermal stability and sulfur resistance are improved by the presence of external surface CeO2 particles, a benefit that applies irrespective of Cu loading.
危险品化学品经营许可证（带存储）