Study On Preparation Of Carbon-based Adsorbent And Its Adsorptive Property For Desulfurization Of Model Diesel Oil

In order to meet stricter standard of the sulfur content of diesel oil for transportation, the removal of sulfur compounds from them has become a more and more important research subject currently. Adsorption desulfurization technology can remove refractory compounds such as DBT and its derivatives in liquid hydrocarbon fuels at ambient pressure and temperature has drawn wide attentions. The greatest challenge in development of an effective adsorptive desulfurization process is to develop an adsorbent with high selectivity and high capacity of the sulfur compounds and at the same time can be easily regenerated.In this paper, home-made rice hull based carbon and several commercial activated carbons were used as adsorbents for removing DBT from model diesel oil.Rice hull as raw material, was chosen to prepare carbon-based adsorbents by ZnCl2activation under the optimized process through orthogonal experiment design. Experiment results showed that the order of key factors was activation temperature>activation time>ZnCl2concentration>the weight ratio of ZnCl2to rice hull. When activation temperature was700℃, activation time was75min, the weight ratio of ZnCl2to rice hull was1:1, the concentration of ZnCl2was60wt%, the adsorbent was made under optimized condition and its static adsorption capacity was26.6mgS/g and its dynamic adsorption capacity was16.8mgS/g. Meanwhile, the adsorption isotherms and adsorption thermodynamics of rice hull based carbon over DBT were studied. The thermodynamic function results show that the adsorption of DBT on rich hull based carbon is an exothermic, irregularity decreased, spontaneous and physical process.Furthermore, ammoniumsalt and heteropolyacid compounds were introduced to modify activated carbons, whose XRD patterns, IR spectra, N2adsorption and Boehm titration were analyzed. Effect of different atmospheres, kind of ammoniumsalt and its loading, kind of heteropolyacid and its loading on DBT removal performance were investigated. The results indicated that activated carbon modified by supported10wt%ammoniumnitrate and treated by heat under air atmosphere showed its static adsorption capacity was29.7mgS/g and its dynamic adsorption capacity was19.1mgS/g.