重油加氢脱氮催化剂的研制──钼镍磷催化剂的表征

STUDY ON HDN CATALYSTS FOR HEAVY FEEDSTOCKCHARACTERIZATION OF Mo-Ni-P CATALYSTS

用pH摆动法制备氧化铝为载体的重油加氢脱氮 (HDN)Mo -Ni-P催化剂及工业Mo -Ni -P催化剂进行了详细表征并与HDN活性关联。FTIR显示催化剂的B酸中心是Mo、Ni与载体相互作用所形成 ;NH3-TPD表明催化剂表面酸量增加。TEM照片显示自制氧化铝、催化剂属精细纤维结构。EPM分析活性组分在催化剂表面及表相和体相中的分布均匀 ;自制催化剂径向Mo的分布有空缺 ,但未影响其脱氮活性。根据UV -Vis漫反射结果推测催化剂HDN活性可能与Mo八面体和Mo四面体的比例有关。Mo、Ni的氨溶出率及催化剂的低温氧吸附 (LTOC)量与其HDN活性有良好相关性 ,氧吸附量在 0 0 7mmol/g以上的催化剂 ,脱氮反应后尾油中N小于 1 0 μg/g。

A hydrodenitrogenation catalyst comprising molybdenum, nickel, and phosphorus components supported on gamma alumina prepared by pH swing method was studied in this paper A commercial Mo-Ni-P/γ-Al2O3 catalyst with 245w% MoO3, 38% NiO and 26% P was also studied A series of modern and physicochemical analytical methods, such as IR, NH3-TPD, TEM, EPM, UV-Vis diffuse reflectance, LTOC and NH3-dissolving test, were employed to characterize the properties of the catalysts and some meaningful information was obtained These analytical results showed: the home made catalyst has the similar acidic properties to the commercial catalyst, but the former has a fine fibrous TEM graph while the latter has obvious particles in its TEM spectra From the EPM and chemical analysis of the composition of the catalysts, it can be found that the distribution of the activated components were well dispersed both on the surface and in the bulk phase of the catalysts From the ultraviolet-visible diffuse reflectance spectra, it can be suggested that the activity of HDN was associated not only with the amount of the Mo[Oct] species but also the ratio of Mo[Oct] and Mo[Tet] The NH3-dissolving test showed that the more the amount of Mo, Ni dissolved was, the better the HDN activity of the catalyst was The HDN activity of the catalyst was well corresponding to its oxygen chemisorption capacity When the amount of oxygen chemisorption of the catalyst was more than 007mmol/gcat, the conversion of nitrogen was higher than 9951w% when a VGO with nitrogen content 2039μg/g was used as feedstock