Modified SARA Method to Unravel the Complexity of Resin Fraction(s) in Crude Oil

Abstract

The complexity of crude oil samples has hindered its detailed analysis and understanding. Although modern analytical methods such as ultrahigh-resolution mass spectrometry have opened the understanding of the molecular composition, discrimination due to the complexity is sabotaging a better understanding. Therefore, the SARA fractionation has been used to reduce complexity by adding a fractionation step prior to analysis. However, our studies indicate that the conventional combinations of solvents used for SARA fractionation are inefficient for the elution of heavier fractions of crude oil from the alumina stationary phase. Adding an additional step to the conventional SARA scheme provides a second resin fraction using ethyl acetate as an additional mobile phase and provides a new material that has not yet been reported. For a better understanding of the differences between both resin fractions, detailed studies have been carried out utilizing ultrahigh-resolution mass spectrometry with different types of ionization methods, one of the best scenarios to reduce discrimination and suppression effects.

Qualitative and Quantitative Evaluation of Sulfur-Containing Compound Types in Heavy Crude Oil and Its Fractions

“…After separation of the asphaltenes, the maltenes were further separated by open tubular chromatography. As previous studies in our lab had shown that a reasonable amount of sample was left on the column after collection of the resin fraction, we introduced an additional elution step to collect a second resin fraction, termed here as resin I and resin II. , Briefly, asphaltenes were first precipitated from the oil by mixing with n -heptane, then filtrated, washed, and re-extracted with toluene as described elsewhere . The remaining maltenes were subjected to separation by open tubular chromatography on activated neutral alumina (Brockman I grade).…”

“…Here, we investigate the possibilities and the limits of the method by using it for a very heavy crude oil and its SARA (saturates, aromatics, resins, and asphaltenes) fractions. In this context, we also employ a recent modification to the traditional SARA scheme that was developed in our lab to include a second resin fraction that had not been recovered from the chromatographic column using the standard protocol. , We use this form of sample preparation to gain additional knowledge on the distribution of sulfur into the different subfractions of an oil, including a formerly neglected part of the oil that was often lost during the fractionation scheme.…”

Synthetic fatty acid from crude oil of Tamsagbulag petroleum deposit (Mongolia)

“…Crude oil, one of the most complex chemical mixtures in the world, serves as a feedstock for the petrochemical industry and as raw material for many chemical products such as fuels, solvents, lubricant oils, plastics, fertilizers, detergents, and others [1,2].…”

“…In this work, we aimed at the possibility of isolating synthetic fatty acid from solid paraffin from the Tamsagbulag crude oil deposit and studied its properties. and fractional composition were determined according to Petroleum Analysis standard methods [2,11,12]. SARA method is used for group composition (oil, resin, and asphaltenes) of crude oil [2,13,14].…”

“…and fractional composition were determined according to Petroleum Analysis standard methods [2,11,12]. SARA method is used for group composition (oil, resin, and asphaltenes) of crude oil [2,13,14]. Experimental to isolate synthetic fatty acids from petroleum were carried out according to the following scheme.…”