Photocatalytic diesel desulfurization using Fe-modified Beta zeolite in a UV-assisted stirred slurry photoreactor: performance and dynamic analysis
摘要
The paper has examined photocatalytic oxidative desulfurization of diesel fuel using a modified Beta zeolite catalyst (5 wt% Fe) in a UV-based stir slurry photoreactor. The objective was to determine the effect of operating conditions on the efficiency of sulphur-removal as well as to support the experimental results by the use of Computational Fluid Dynamics (CFD) to analyse the internal flow and mixing patterns. The synthesis of catalysts was done via wet impregnation, and the catalysts were characterised using X-ray diffraction (XRD), N 2 adsorptiondesorption analysis, NH 3 -TPD, and UV-Vis diffuse reflectance spectroscopy; the iron loading was determined using ICP-OES. Sulphur removal was systematically investigated with regard to the temperature (40–80 o C), reaction time (40–100 min), and the stirring speed (300–700 rpm). Within the ranges of temperature, contact time, and stirring speed, the removal of sulphur rose with temperature, length of contact time, and stirring speed. The highest reported sulphur-removal efficiency was 95.45 per cent at 80 o C, 100 min, and 700 rpm. The CFD findings showed that the increase in desulfurization performance was in line with the experimentally observed increase in the hydrodynamic behaviour and mixing at high stirring speeds. The results indicate that Fe-modified Beta zeolite is a potential catalyst to be used in photocatalytic desulfurization of diesel under relatively mild operating conditions, which is an alternative approach to deep sulphur removal less harsh than hydrodesulfurization.