Catalytic Oxidative Desulfurization of Heavy Naphtha Fraction Over a PMN550 Catalyst, Reactivity and a Kinetic Model

Abstract

Desulfurization of heavy naphtha by a catalytic oxidation process combining hydrogen peroxide with organic and inorganic acids and in the presence of a PMN550 catalyst. This study was conducted to find out the effect of many variables on the efficiency of the process, especially the effect of hydrogen peroxide, the amount of acid, temperature, residence time, weight of the catalyst (0.01-0.6) g, temperature (20-120) C, residence time (20-140) minutes, ratio hydrogen peroxide to heavy naphtha (0.1-0.6) ml and ratio acid to heavy naphtha (0.01-0.175) ml. The catalytic oxidation process depends on all of the above variables. Desulphurization of heavy naphtha using organic and inorganic oxidizers in combination with hydrogen peroxide, glacial acetic acid, phathalic acid, malic acid, sulfuric acid and formic acid. The maximum removal of sulfur was with sulfuric acid and formic acid, which are 50%, 55%, respectively. The catalytic oxidation process carried out In two steps: the first step was the catalytic oxidation at a moderate temperature and atmospheric pressure, and the second step was to extract the oxidized mixture with a methanol-water mixture. The efficiency of the catalytic oxidation process carried out in the presence of PMN550 reached 99%. The catalyst was manufactured in the laboratory and a set of catalyst tests were performed on it FT-IR, AFM, BET, XRD, and XRF, which proven its efficacy. Mathematical models of the relevant reactions were developed to match the experimental results by obtaining the optimal kinetic parameters. Using optimization methods, the maximum conversion rate was 99%, at a temperature of 90°C, a residence time 60 minutes and the initial concentration was 651.3ppm.