Determination of Asphaltenes in Crude Oil and Petroleum Products by the on Column Precipitation Method

An improved analytical method for the determination of asphaltene content in crude oils and petroleum products was developed. This method uses an on-column precipitation and redissolution technique coupled with an evaporative light scattering detector (ELSD). Among the improvements is a quantification of the asphaltene content using a calibration procedure, and the redissolution agent is replaced with a blend with a better solvent power. The method requires a small amount of sample, it takes only 20 min to perform and can quantify asphaltene contents as low as 120 ppm with a relatively low error. It can be automated, and it also has the potential to be used on line. It has better repeatability and reproducibility than the traditional gravimetric methods, which are the actual standards. This work also includes results from preparative experiments that support the reliability of the described methodology. All of these characteristics make this on-column method a good candidate for the monitoring of processes in the oil industry.