Hydrogenation of aromatics in synthetic crude distillates catalyzed by platinum supported in molecular sieves

Catalytic hydrogenation of synthetic crude distillates from Canadian oil sands was carried out over platinum metal supported in pillared interlayered clay (PILC) and Y-zeolite. The molecular sieve supports were employed to modify the properties of dispersed platinum particles and improve their resistance to poisoning by sulfur. The objective was to reduce the distillate aromatic content to meet diesel emission control standards and cetane number requirements. Catalysts were prepared in a series of steps, and metal precursor was loaded using ion-exchange procedures. Characterization was done using X-ray diffraction, hydrogen chemisorption, and proton-induced X-ray emission elemental analysis. Catalytic hydrogenation reactions were carried out by processing distillate feedstocks both high (>100 ppm) and low (<10 ppm) in sulfur using a continuous-flow automated microreactor system. Experimental runs were performed to determine the reaction kinetics and Arrhenius parameters as a means of evaluating and comparing catalyst performance. Significant differences in catalyst activity were found. The Pt/Y-zeolite-alumina catalyst showed a much superior hydrogenation performance under conditions of high sulfur content. The extent of cracking and ring opening was also evaluated and was shown to be minimal under the operating conditions employed.