La_2O_3-CeO_2/γ-Al_2O_3催化剂还原脱硫耐氧特性及其反应机理研究

La_2O_3-CeO_2/γ-Al_2O_3 catalysts for CO reduction of SO_2 in the presence of oxygen

用浸渍法制备了一系列稀土催化剂,研究了其催化CO还原SO2为单质硫的耐氧特性及影响其耐氧性能的主要因素,运用XRD技术分析了催化剂物相的变化及脱硫产物成分。结果表明,12%La2O3-8%CeO2/γ-Al2O3复组分催化剂比其他La2O3-CeO2/γ-Al2O3催化剂具有更好的耐氧性能;脱硫温度、催化剂用量、SO2与CO的摩尔比等对催化剂的耐氧性能均有明显的影响。最后,探讨了稀土催化剂脱硫机理,并分析在有O2条件下,引起脱硫率下降的原因是反应过程中O2与CO、S发生了竞争性反应。

Many experimental runs of CO reduction of SO2 were performed using 5 lab prepared La2O3-CeO2- Al2O3 catalysts to determine the effects of composition and dose of the catalyst, reaction temperature, and molar ratio of SO2/CO in the feed stream on reduced SO2 conversion due to 0. 1%-0. 5% of oxygen in the feed. The 12% La2O3-8% CeO2/γ-Al2O3 catalyst was the best catalyst of the 5 producing in the least decline in SO2 conversion. Higher catalyst dose, higher reaction temperature, and more CO in the feed all resulted in less declines in SO2 conversion. The mechanisms of catalytic desulfurization and catalyst deactivation were proposed based on the XRD spectra for the catalysts before and after hydration and desulfurization. The catalyst was activated by hydration and that deactivation was caused by the comoeting reactions of oxygen with CO and elemental S from the SO2 conversion.