Alternative Processes for Removing Organic SulfurCompounds from Petroleum Fractions

This work discusses the processes for removing sulfur from fuels, and problems related thereto, including conventional and improved processes of hydrodesulfurization, and alternative technologies and processes for obtaining fuel with extremely low sulfur content, which are in the process of research and development. It is anticipated that alternative processes already developed or those being researched will be applied as an addition to the currently most commonly used process of hydrodesulfurization, which is based on selective heterogeneous catalysts. Reviewed are new achievements in the developmentof the hydrodesulfurization process regarding new catalysts and reactors, the research and development possibilities of the adsorption and extraction processes, as well as the biodesulfurization process

Oxidative Desulphurization of Diesel Fuels

Oxidative desulphurization (ODS) enables attainment of ultra-low sulphur content in diesel fuels by oxidation of refractory sulphur compounds that are difficult to remove with hydrodesulphurization when the sulphur content needs to be attained below 10 mg kg–1. In this work, the effect of the process conditions of ultrasound-assisted ODS (using N,N-dimethylformamide and methanol as extraction solvents) on real diesel fuels was researched. The experiments were conducted in a batch reactor with hydrogen peroxide as oxidant and acetic acid as catalyst. Temperature increase, reaction time extension, and increase in the amount of dibenzothiophene (DBT) in real diesel fuels showed a positive impact on the ODS process efficiency. Comparison of ultrasound-assisted ODS and ODS in a mechanically stirred system revealed a significant reduction in reaction time. The very low sulphur concentrations (3 mg kg–1) in the product obtained after 30 minutes of oxidation confirmed high efficiency of the oxidative desulphurization

A Design of Experiments Investigation of Adsorptive Desulfurization of Diesel Fuel

Adsorptive desulfurization of diesel fuel was investigated applying two Design of Experiments (DOE) methods. The experiments were carried out in a batch adsorption system using Chemviron Carbon SOLCARBTM C3 activated carbon as adsorbent. The first DOE method employed was a full factorial with three factors on two levels and five center points, and the second was Box-Behneken design with the same three factors but on three levels. The effects of individual factors and their interactions on sulfur concentration and sorption capacity were determined, and statistical models of the process developed. The first-order models predict the behavior of the system rather well but significant curvature was detected. Subsequently developed second-order models were able to give reasonably well descriptions of the system. The lowest achieved output sulfur concentration was 7.6 mg kg–1 with relatively low sorption capacity of 0.0861 mg g–1