Utilization of agricultural waste (rice husk) in synthesis of TS-1 zeolite as a support for NiMo nanocatalyst employed in hydrodesulfurization of heavy oil

Abstract

Agricultural waste, rice husk (RH) was treated to obtain rice husk ash (RHA) and utilized as silica precursor in hydrothermal synthesis of TS-1 zeolite. Results of characterization analyses, XRD, FTIR, FESEM and N2 adsorption-desorption, confirmed that TS-1 zeolite was properly synthesized from RHA. Synthesis of TS-1 was also carried out with TEOS for comparison of textural properties. Prepared TS-1 zeolite with RHA was used as support for HDS catalyst preparation. Molybdenum active phase and nickel promoter were loaded via three different methods, impregnation, precipitation and solution combustion, to obtain NiMo/TS-1 hydrodesulfurization catalyst. EDX dot-mapping and H2-TPR analyses indicated on better preparation of NiMo/TS-1 catalyst by solution combustion method, in terms of distribution and amount of successfully loaded metal over the support surface. Hydrodesulfurization (HDS) activity of synthesized samples was examined in hydrodesulfurization of heavy oil feed, carried out in a continuous fixed bed reactor apparatus. Performance test revealed that NiMo/TS-1 catalyst synthesized by solution combustion method eliminated 63.5 % of the feed sulfur content (4000 ppm); a superior hydrodesulfurziation activity, compared to the samples prepared via impregnation and precipitation methods with 40.8 % and 50.2 % sulfur removal, respectively. Amount of sulfur present in the feed and treated product was determined with GC-MS analysis.