Jasim Ibrahim Humadi

The production of clean fuel with stringent limits on harmful contaminants is one of the petroleum refinery industry’s main goals for improving environmental conditions and being eco-friendly. Iron oxide (Fe₂O₃) loading over composite support (γ-Al₂O₃–TiO₂) was synthesized and evaluated for oxidative desulfurization (ODS) via the incipient wetness impregnation (IWI) procedure. To prolong the lifetime of the nanocatalyst, it was coated with a newly developed manganese compound via IWI technology to suppress substantial deactivation. The composite support, uncoated nanocatalyst, and coated nanocatalyst were tested by different methods of characterization: BET, XRD, FT-IR, FESEM-EDX, mapping, and TEM. The XRD and FTIR results indicated that the composite nanosupport was designed successfully. The FESEM-EDX results indicated high Fe₂O₃ dispersions on the composite nanosupport, and the TEM result represented a good layer of Mn-coated material over the nanocatalyst. The ODS in a newly oscillatory helical baffled reactor (OHBR pilot plant) is utilized to test the performance of the prepared nanocatalysts. Oxidative desulfurization utilized peracetic acid as an oxidant and moderate operating conditions. From the experimental results, it was observed that the optimal desulfurization was 98.42% in the best conditions (amplitude of oscillation = 8 mm, frequency of oscillation = 2 Hz, and oxidation time = 9 min) with an uncoated nanocatalyst. With the coated nanocatalyst, the optimal removal was 96.57% under the same conditions. The uncoated nanocatalyst exhibited good reusability, with sulfur removal decreasing from 98.42% to 87.23% after five consecutive cycles.

In the present study, a kinetic model was developed for the process of oxidative desulfurization of light gas oil with 7329 ppm sulfur using a newly synthesized nanocomposite catalyst. The batch reactor experiments were conducted at different thermal conditions (313–373 K) and reaction times (30–90 min) to explain this endeavor of desulfurization performance as a function of these variables, targeting the design of a reliable reactor system. Carbon nanofibers (CNFs) were integrated into the support γ-Al₂O₃ at various concentrations of 5%, 7.5%, and 10% to improve mechanical properties, surface area, and distribution of active metals. The nanocomposite support was impregnated with molybdenum trioxide (MoO₃) and iron oxide (Fe₂O₃) to form four variants of the catalyst: CAT-1 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ + 5% CNF, CAT-2 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ + 7.5% CNF, CAT-3 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ + 10% CNF, and CAT-4 with 10% MoO₃ + 5% Fe₂O₃/Al₂O₃ with no CNF. CAT-3 had the best effectiveness for sulfur removal with 87.5% at 373 K and a reaction time of 90 min. The model predicts a maximum sulfur removal rate of 99.86% under optimal conditions of 550 K and 200 min (for an initial sulfur concentration of 7329 ppm). The experimental and modeling results therefore indicate the potential of the developed catalyst system, while the optimum condition at 550 K and 200 min should be interpreted as a model-predicted outcome. The development of such highly efficient nanocatalysts for deep desulfurization is a crucial advancement in green chemistry, directly contributing to the production of cleaner fuels to mitigate air pollution and supporting the aims of the United Nations Sustainable Development Goals (SDGs), particularly SDG 9 (Industry, Innovation, and Infrastructure) and SDG 12 (Responsible Consumption and Production). From a sustainability perspective, the proposed ODS system supports cleaner fuel production and reduced sulfur-derived emissions, while operating-condition optimization helps improve process efficiency in support of more sustainable refining strategies.

The oscillatory baffled reactor (OBR) is one of the most promising reactor types for oxidative desulfurisation (ODS) due to high proven sulfur removal efficiency and improved mass and heat transport steps through the oxidation reaction. In Part III of this literature review, we review OBR design, scale-up, industrial application and economic considerations. Practical application of OBR for ODS process is described, catalytic systems are presented and the remaining challenges are outlined.