Eco-friendly desulfurization for production ultraclean fuel using coated and uncoated composite magnetic-activated carbon catalyst in new oscillatory baffled reactor: Experiments and optimal kinetic prediction

Abstract

In this work, continuous oxidative desulfurization (ODS) of diesel fuel in novel oscillatory basket central baffled reactor utilizing hydrogen peroxide (H₂O₂) oxidant and new synthetic coated (alumina) and uncoated magnetic composite catalyst (5 % MnO₂–3 % Fe₂O₃/AC) is studied. Desulfurization efficiency is performed at various effects operation conditions including reaction temperature and residence time, and oscillation conditions (amplitude and frequency). Results is proved that increasing reaction temperature and residence time remarkably promotes the efficiency of ODS owing to accelerated reaction kinetics and improved molecular diffusion. Moreover, higher oscillation conditions (frequency and amplitude) enhanced intensity of mixing and regeneration of the catalyst surface, which leads to increased removal of sulfur compounds. Also, alumina coating is found to hinder sulfur removal, likely due to disturbance in the transport of reactants to the active sites. The new magnetic composite catalysts are achieved remarkable removal efficiency of 98.1 % (uncoated) and 96 % (coated) at the best mild conditions (90 °C, 12 min, 2 Hz, and 12 mm). Kinetic modeling proved that order of reaction and activation energy are significantly changed under the effect of oscillation conditions, indicating promoted mass transfer and efficiency of mixing. The results of mathematical model show low sum of squared error (SSE) values on the order of 10⁻⁵ to 10⁻⁶, revealing a high agreement between experimental and predicted data.