面向工业应用的焦炉煤气预加氢脱硫催化剂失活机理

Deactivation mechanism of coke oven gas prehydrogenation desulfurization catalyst for industrial application

以焦炉煤气深度净化过程使用的预加氢转化新鲜催化剂和失活催化剂为研究对象,利用微型固定床反应装置对新鲜催化剂和再生催化剂进行加氢脱硫(HDS)活性评价,并采用N_(2)-吸脱附仪、X射线衍射、Raman光谱、热重分析仪、扫描电子显微镜、电子能谱仪、紫外可见分光光度计和高频红外碳硫仪进行表征,深入研究了预加氢转化催化剂的积炭失活机理。研究结果发现,积炭覆盖催化剂表面活性位和堵塞催化剂孔道是导致预加氢转化催化剂失活的主要原因,同时积炭过程伴随活性组分(Fe和Mo)流失及再生过程中催化剂的烧结对催化剂失活也有贡献;积炭的形态以球形石墨化碳为主,其分布形式从催化剂内部向外逐渐增加;除异形条状和五齿球的失活催化剂外,其他催化剂再生(600℃,空气气氛)后可继续使用,再生后催化剂加氢活性下降,这主要是因为催化剂比表面积、孔容的下降及活性组分的流失。

Taking the pre-hydrogenation conversion fresh catalyst and deactivated catalyst used in the deep purification process of coke oven gas as the research object,we used a micro-fixed-bed reaction device to carry out the hydrodesulfurization(HDS)activity evaluation.The carbon deposition and deactivation mechanisms of pre-hydrogenation reforming catalyst were explored by characterizations using N_(2)-sorption desorption apparatus,X-ray diffraction(XRD),Raman spectroscopy,thermo-gravimetric analysis(TG-DTG),scanning electron microscope with energy dispersive spectrometer(SEM-EDS),UV-Vis spectroscopy and high-frequency infrared carbon-sulfur analyzer.The research result showed that the carbon deposition covering the active sites on the catalyst surface and the catalyst pore blocking were the main deactivation reasons.Meanwhile,the loss of active components(Fe and Mo)during the process of carbon deposition and the catalyst sintering during regeneration process also contributed to the deactivation of the catalysts.Secondly,the form of carbon deposition is dominated by spherical graphitic carbon,increasing gradually from the inside of the catalyst to outside.Finally,except for the catalysts of anisotropic strips and pentagonal spheres,other deactivated catalysts can be reused after regeneration(600°C,air atmosphere).However,the hydrotreating activity of the catalysts decreased after regeneration,mainly due to the reduction of the catalysts'surface,pore volume and the loss of active components.