Inhibition of Asphaltene Precipitation by TiO2, SiO2, and ZrO2 Nanofluids

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• 作者：Mohsen Mohammadi ; Mahdi Akbari ; Zahra Fakhroueian ; Alireza Bahramian ; Reza Azin ; Sharareh Arya
• 刊名：Energy & Fuels
• 出版年：2011
• 出版时间：July 21, 2011
• 年：2011
• 卷：25
• 期：7
• 页码：3150-3156
• 全文大小：998K
• 年卷期：v.25,no.7(July 21, 2011)
• ISSN：1520-5029

文摘

Asphaltene precipitation causes several problems during crude oil production, transportation, and refinery processes. Therefore, finding an inhibitor to prevent or delay asphaltene precipitation is of paramount importance. In this work, effects of TiO₂, ZrO₂, and SiO₂ fine nanoparticles in organic-based nanofluids have been investigated to study their potential for stabilizing asphaltene particles in oil. To this end, polarized light microscopy has been applied to determine the onset of asphaltene precipitation by titration of dead oil samples from Iranian crude oil reservoirs with n-heptane in the presence of nanofluids. Results show that rutile (TiO₂) fine nanoparticles can effectively enhance the asphaltene stability in acidic conditions and act inversely in basic conditions. It was found that the required amount of n-heptane for destabilizing the colloidal asphaltene is considerably higher in presence of TiO₂ nanofluids at pH below 4. The FTIR spectroscopy indicates changes in n-heptane insoluble asphaltene when acidic TiO₂ nanofluid is used as inhibitor. According to the results obtained by FTIR spectroscopy, TiO₂ nanoparticles can enhance the stability of asphaltene nanoaggregates through formation of hydrogen bond at acidic conditions. This is while other materials used in this experiment, as well as the TiO₂ nanoparticles in basic conditions, are unable to form any hydrogen bond 鈥?hence their incapability to prevent asphaltene precipitation. Dynamic light scattering (DLS) measurements also have been performed to explain the mechanism of asphaltene precipitation in the presence of nanoparticles.