New EDXRF Method for Analysis of Sulphur, Vanadium and Nickel in Crude Oil

Applied Rigaku Technologies, Inc. (USA) announced a new empirical method for the analysis and measurement of sulphur, vanadium and nickel in crude oil by energy dispersive X-ray fluorescence (EDXRF). The report provides details about sample preparation, calibration and repeatability, and demonstrates the performance of the new Rigaku NEX DE EDXRF Spectrometer.

Sulfur, vanadium and nickel occur naturally in crude oil. Their concentrations vary depending on the geographical region of the oil deposits. High levels of vanadium and nickel can adversely affect the refining process, making crude oil with low levels of vanadium and nickel more desirable. Excess levels must therefore be removed before refining.

At the refinery, midstream in pipelines and at gathering points, a quick and easy means of screening and
monitoring vanadium and nickel levels is essential for characterising the quality of the crude. The NEX DE EDXRF analyser is designed to meet this industry analytical need. New excitation and detection technology in the instrument achieves up to 500,000 cps throughput and very low background levels, yielding a 2X improvement in detection limits over previous models, making the NEX DE analyser an ideal multi-element tool for monitoring the concentrations of not only sulphur, but also metals in crude, residuals and other heavy hydrocarbons. Additionally, the unit’s powerful QuantEZ Windows-based software gives technical and nontechnical operators alike a user-friendly interface for conducting analyses. 

For the application described in the report, empirical calibrations were built using a suite of ten commercially available mineral oil standards. Two calibration standards were measured in 10 repeat analyses using an analysis time of 600 seconds per sample to demonstrate precision.

The results indicate that, given stable samples, proper sample handling and calibration technique, the NEX DE analyser achieves excellent performance for monitoring sulfur and metals in oil. The method demonstrates that the Rigaku NEX DE analyser delivers a simple yet powerful and versatile system for quantifying multi-elemental composition using the empirical approach.