Karevan Azadeh, Zirrahi Mohsen, Hassanzadeh Hassan
Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
ACS Omega. 2022 May 24;7(22):18897-18903. doi: 10.1021/acsomega.2c01880. eCollection 2022 Jun 7.
One of the main approaches for compositional analysis of crude oils is SARA fractionation in which the sample is separated into saturate, aromatic, resin, and asphaltene fractions based on their polarity. A fully automated standardized SARA analysis for bitumen and heavy crudes has been developed and optimized using three commercial columns packed with different stationary phases based on the combination of adsorption and partition chromatography. The system is equipped with automated six-, eight-, and ten-port switching valves that control the flow direction. In this analytical technique, a bitumen (or heavy oil) sample diluted in toluene is swept through the column by pentane as the primary carrier phase. The sample is separated into four fractions by selective retention through interactions with the solvent mobile phases and the column stationary phases. The poly(tetrafluoroethylene) (PTFE) column filters asphaltenes, ZORBAX CN absorbs resins, and ZORBAX RX-SIL retains aromatics. Three samples of bitumen and heavy oils were fractionated to their SARA fractions by the developed method. Consistent results were obtained, proving the applicability of the new analytical technique to a wide range of crude oil samples. In addition, the performance of the developed SARA high-performance liquid chromatography (HPLC) method was compared with the conventional method, which demonstrates that it is more efficient, cost-effective, and consistent.
原油成分分析的主要方法之一是SARA分馏，即根据样品的极性将其分离为饱和烃、芳烃、树脂和沥青质馏分。基于吸附和分配色谱法的结合，使用填充不同固定相的三根商用柱，开发并优化了一种用于沥青和重质原油的全自动标准化SARA分析方法。该系统配备了控制流动方向的自动六通、八通和十通切换阀。在这种分析技术中，以戊烷作为主要载气，将稀释在甲苯中的沥青（或重油）样品吹扫通过色谱柱。样品通过与溶剂流动相和色谱柱固定相的相互作用进行选择性保留，从而分离为四个馏分。聚四氟乙烯（PTFE）柱过滤沥青质，ZORBAX CN吸附树脂，ZORBAX RX-SIL保留芳烃。采用所开发的方法对三个沥青和重油样品进行了SARA馏分分离。获得了一致的结果，证明了这种新分析技术对广泛的原油样品的适用性。此外，将所开发的SARA高效液相色谱（HPLC）方法的性能与传统方法进行了比较，结果表明该方法更高效、更具成本效益且更稳定。
