Performance Evaluation Of The Heteropoly Compounds As Catalyst For The Deep Desulfurization Of Diesel Oil

The presence of sulfur compounds in transportation fuels has been recognized as a major source of SOx which contributes to air pollution, acid rain and damage of exhaust after-treatment devices. With the issues of increasingly stringent legislations on sulfur level in transportation fuels, the development of clean fuels with lower sulfur content has become a globle trend in environmental field. Oxidative desulfurization(ODS), which requires mild conditions as ambient temperature and atmospheric pressure, is one of the most promising desulfurization processes and was focusd by worldwide researchers. In ODS process, organosulfur compounds was oxidized to corresponding polarity sulfoxide and sulfone products. Then the products can be removed by extraction or absorption processes. Particularly, the performance of catalysts determines the desulfurization efficiency. Heteropoly compounds (HPCs), known as green catalysts, are regarded as potential catalysts for deepen desulfurization.In this paper, various structured HPCs and composite type HPCs were prepared and were evaluated with hydrogen peroxide as the oxidant in catalytic oxidative experiment. The catalysts with highest catalytic activiy for ODS were determined selected. Meanwhile, main factors affecting the process were investigated to determine the optimum reaction condition by contrast experiments. Finally, The practical application of the catalyst was exemplified in veritable diesel oil under favorable conditions. The paper is composed of the following three sections.In the first section, the Keggin type, Dawson type and lacunary type HPCs were evaluated as promising catalytic agents for the oxidation of dibenzothiophene with hydrogen peroxide in a normal octane/acetonitrile biphasic system and the representative catalyst with highest activity was chosen in three experiment systems respectively. Furthermore, the key factors affecting the reaction were investigated. The conditions favourable to the reaction were also determined. Meanwhile, the performance of the catalyst for the oxdition of refractory organosulfur compounds was testified in the favourable conditions. In the second section, the supported type Cs2.5H0.5PW12O40/SiO2 and the "ship-in-the-bottle" type HPCs were studied as promising catalytic agents for the oxidation of dibenzothiophene with hydrogen peroxide, and the representative catalyst with highest activity was chosen in the two experiment systems respectively. Furthermore, the key factors affecting the reaction were investigated and the optimum conditions were also determined.In the third section, the practical application of the catalysts, including lacunary type HPCs, supported type Cs2.5H0.5PW12O40/SiO2 and the "ship-in-the-bottle" type HPCs, were exemplified in veritable diesel oil under favorable conditions.