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Diesel fuel desulfurization by different commercial activated carbons was studied in a batch adsorber. Experiments, carried out to determine the sulfur adsorption dependency on time, were used to perform kinetic characterization and to screen the best performing activated carbon. The equilibrium characterization of the adsorption process was also performed. The statistical study of the process was undertaken by way of a two-level one-half fractional factorial experimental design with five process parameters. Individual parameters and their interaction effects on sulfur adsorption were determined and a statistical model of the process was developed. Chemviron Carbon SOLCARB TM C3 was found to be the most efficient adsorbent. The kinetic pseudo-second order model and Freundlich isotherm are shown to exhibit the best fits of experimental data. The lowest achieved sulfur concentration in treated diesel fuel was 9.1 mg kg -1 .

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Adsorptive desulfurization enables the attainment of ultra-low sulfur content in hydrocarbon fuels by removing the refractory sulfur compounds, which are difficult to remove in hydrodesulferization (HDS) processing when sulfur concentrations below 10 mg kg -1 must be attained. In this work, diesel fuel was desulfurized by adsorption using activated carbon as an adsorbent and the adsorption was carried out in a fixed-bed column. The output sulfur content of less then 0.7 mg kg -1 was achieved for the lowest flow rate of 1.0 cm 3 min -1 and the highest bed depth of 28.4 cm at 50°C. In all the experiments, at least one output sample contained less then 10.0 mg kg -1 of sulfur with a longest achieved breakthrough time of 11.8 h. A mathematical model of the fixed-bed adsorber was applied to describe the kinetics and to estimate the breakthrough curves. The model equations included a differential material balance for a liquid phase and a mass transfer rate expression. The ability of the model to fit the experimental data was shown to be satisfactory.

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