Optimization of Extraction Induced by Emulsion Breaking Variables for Subsequent Determination of Crude Oil Salinity by Ion Chromatography

Abstract

Due to natural geological oil formation and exploration processes, high amounts of saltwater are emulsified in oil, resulting in high salinity in oil extraction wells. This salinity is due to the presence of non-metals of forming inorganic salt, such as chloride, which, when subjected to high temperatures, tend to react with water vapor to form hydrochloric acid, causing distillation tower corrosion. In this context, extraction induced by emulsion breaking (EIEB) has been as an alternative procedure to the official ASTM D6470 method for chloride extraction and subsequent determination by ion chromatography in oil samples. Thus, the experimental EIEB variables of HNO3 volume (V) and Triton X-114 mass (T) were optimized using a 22 factorial design with three central points. The optimal condition obtained for the EIEB and chloride determination was V = 500 µL and T = 0.5000 g. The developed procedure allowed for the assessment of samples presenting different °API (22.9 to 28.8), which originated from the post-salt. Besides, limits of detection of 0.3 - 0.4 mg kg−1 chloride were achieved. The accuracy of the procedure was confirmed by addition/ recovery tests (100.4 - 100.7%).