Experimental Investigation on the Effect of Aliphatic Ionic Liquids on the Solubility of Heavy Crude Oil Using UV鈥揤isible, Fourier Transform-Infrared, and 13C NMR Spectroscopy

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• 作者：Sivabalan Sakthivel ; Sugirtha Velusamy ; Ramesh L. Gardas ; Jitendra S. Sangwai
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：September 18, 2014
• 年：2014
• 卷：28
• 期：9
• 页码：6151-6162
• 全文大小：766K
• ISSN：1520-5029

文摘

Chemical treatment of aromatic heavier hydrocarbons are traditionally done by using cyclic aromatic nonpolar solvents, such as benzene, xylene, and toluene, which have the capability to dissolve asphaltenes. However, these aromatic solvents are volatile and hazardous and hence not advisable to use. Alternatively, lighter hydrocarbons, such as heptane, hexane, etc., show lesser solubility. It is, therefore, crucial that these problems require intelligent, cost-effective, and innovative solutions. The present work investigates the possible solution for the dissolution of heavy crude oil using the application of eight aliphatic ionic liquids (ILs) along with five solvents, namely, toluene, heptane, decane, ethyl acetate, and hexane. Ionic liquids (ILs) based on [CH₃COO]^{鈭?/sup>, [BF₄]鈭?/sup>, [H₂PO₄]鈭?/sup>, and [HSO₄]鈭?/sup> as anions and with various cations, such as di- and tri-alkyl ammonium, are considered. The enhancement in the solubility of heavy crude oil in solvent + ILs mixture is investigated using Ultraviolet鈥搗isible (UV鈥搗is) spectrophotometry, Fourier transform-infrared spectroscopy (FT-IR), and 13C-nuclear magnetic resonance (NMR) spectroscopic techniques. The absorbance of the sample solution (heavy crude oil + solvent + IL) is compared with the standard solution (heavy crude oil in neat solvent alone). It is observed that the dissolution of heavy crude oil is more in the solution with IL than with the solvent alone. Solubility of heavy crude oil in solvents increases to about 70% in the presence of ILs. Hold-time study is also performed to understand the maximum time required for efficient dissolution of heavy crude oil. The hold-time study reveals that solubility of heavy crude oil in heptane increased to about 61鈥?22% in the presence of ILs, as compared to 11鈥?6% in the case of standard solution for a prolonged period of 30 days.}