engleski

Ultrasound assisted oxidative desulfurization of model diesel fuel

Ultrasound assisted oxidative desulfurization (UAOD) was applied to reduce sulfur compounds from model diesel fuel. Diesel fuels are a mixture of complex mixtures of alkanes, cycloalkanes, and hydrocarbons with carbon number range of C9-C28 and with a boiling range of 150-390 °C 1. Very stringent environmental regulations have limited the level of sulfur in diesel to 15 μg/g since 2006 in US, less than 10 μg/g in EU, and less than 50 μg/g since 2008 in Bejing and Shanghai in China 2, 3 these regulations require deep desulfurization of fuels. Hydrodesulfurization (HDS) is presently the most used industrial process to eliminate sulfur compounds from diesel oil, highly effective in removing mercaptanes, thiols, sulfides, disulfides, but a lot less effective for removing tiophene sulfur compounds (benzotiophene, dibenzotiophene, 4, 6 dimethyldibenzotiophene)1. UAOD is a new technology that has several advantages over HDS, can be performed under mild conditions, atmospheric pressure and temperatures till 100°C, higher reactivity of aromatic compounds and no use of hydrogen 4 , converts tiophenic compounds into sulfoxides and sulfones which are highly polar and easy to remove. Nowadays, different catalyst/oxidants systems3 are being researched to improve reaction efficiency and enhance the mass transfer in the interfacial region. 2, 4. In this work the effect of reaction temperature and oxidation time of model diesel fuel with hydrogen peroxide/acetic acid, in 70 ml batch reactor. The temperature range was 20-90°C, under 30 minutes. The results indicate a rise in the yield of sulfones at higher temperatures and higher rate of stirring. Extraction with N, N- dimethylformamide was conducted after the process of oxidation and the effect of solvent/oil ratio and temperature was investigated. Gas chromatography method was used for identification of sulfur containing compounds formed during the oxidative desulfurization process. The aim of this paper is to determine the efficiency of model diesel fuel ultrasound assisted oxidative desulfurization (UAOD) process. The effects of oxidation process parameters ; reaction temperature and oxidation time on dibenzotiophene conversion, as well as the effects of oil phase extraction process parameters ; solvent/oil ratio and temperature on process efficiency, were investigated.

ultrasound asisted oxidative desulfurization; dibenzothiophene

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