Saturate, aromatic, resin and asphaltene
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Saturate, Aromatic, Resin and Asphaltene (SARA) is an analysis method that divides crude oil components according to their polarizability and polarity. The saturate fraction consists of nonpolar material including linear, branched, and cyclic saturated hydrocarbons (paraffins). Aromatics, which contain one or more aromatic rings, are slightly more polarizable. The remaining two fractions, resins and asphaltenes, have polar substituents. The distinction between the two is that asphaltenes are insoluble in an excess of heptane (or pentane) whereas resins are miscible with heptane (or pentane).
There are three main methods to obtain SARA results. One has lately emerged as the most popular. That technology is known as the Iatroscan TLC-FID, it combines TLC with flame ionization detection (TLC-FID). It is referred to as IP-143. Other analysis giving SARA numbers might not correspond to the numbers obtained in IP-143. It is therefore always important to know the analysis method when comparing SARA numbers.
It is the only method that is 100 times more sensitive than any old method and faster. Takes 30 seconds for 1 sample instead of 1 day.
- Tianguang Fan, et al. (2002). "Evaluating Crude Oils by SARA Analysis" Society of Petroleum Engineers, Proceeding of SPE/DOE Improved Oil Recovery Symposium, 13–17 April 2002, Tulsa, Oklahoma