Effects of synthesis methods of wet impregnation and sol-gel and competitive hydrocarbons on oxidation of dibenzothiophene over titania-silica nanocatalyst

Document Type : Research Article

Authors

1 School of Chemical, Petroleum, and Gas Engineering, Iran University of Science and Technology, Tehran, Iran

2 Iran University of Science and Technology

3 Energy and Environment Research Center, Niroo Research Institute, Tehran, Iran

Abstract

Liquid hydrocarbon fuels contain high amounts of sulfur compounds. Combustion of these compounds causes SOx emission that is harmful to the environment. The oxidative desulfurization (ODS) process is a promising complement process to the hydrodesulfurization (HDS) to remove refractory sulfur compounds of liquid hydrocarbon fuels under low temperature and atmospheric pressure. In this study, the performance of catalytic oxidative desulfurization was considered using titania-silica catalysts which were synthesized by different methods, i.e., wet impregnation and sol-gel method. The catalyst samples were then characterized by N2 adsorption-desorption and Fourier-transform infrared spectroscopy (FTIR). The oxidative desulfurization was conducted in a batch reactor with model fuel that consisted of 500 ppmw sulfur as dibenzothiophene in n-dodecane with tert-butyl hydroperoxide (t-BuOOH) as an oxidant and the molar ratio of oxidant to sulfur (O/S) was 5. The catalyst dosage was 0.03 g for 3 g of model fuel and T=50 °C and P=1 atmosphere. Moreover, the effects of reaction temperature as well as nitrogen and olefin compounds were investigated. The conversion of dibenzothiophene was determined with the gas-chromatography equipped pulsed flame photometric detector (PFPD). The best catalytic activity was observed for the sample synthesized by the sol-gel method that achieved 100% DBT conversion after only 30 min of the reaction at 50°C.

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