【国外标准】 Standard Test Method for Vanadium and Nickel in Crude and Residual Oil by X-ray Spectrometry

5.1 This test method provides a rapid and precise elemental measurement with simple sample preparation. Typical analysis times are approximately 4 min to 5 min per sample with a preparation time of approximately 1 min to 3 min per sample.5.2 The quality of crude oil is related to the amount of sulfur present. Knowledge of the vanadium and nickel concentration is necessary for processing purposes as well as contractual agreements.5.3 The presence of vanadium and nickel presents significant risks for contamination of the cracking catalysts in the refining process.5.4 This test method provides a means of determining whether the vanadium and nickel content of crude meets the operational limits of the refinery and whether the metal content will have a deleterious effect on the refining process or when used as a fuel.1.1 This test method covers the quantitative determination of total vanadium and nickel in crude and residual oil in the concentration ranges shown in Table 1 using X-ray fluorescence (XRF) spectrometry.1.2 Sulfur is measured for analytical purposes only for the compensation of X-ray absorption matrix effects affecting the vanadium and nickel X-rays. For measurement of sulfur by standard test method use Test Methods D4294, D2622 or other suitable standard test method for sulfur in crude and residual oils.1.3 This test method is limited to the use of X-ray fluorescence (XRF) spectrometers employing an X-ray tube for excitation in conjunction with wavelength dispersive detection system or energy dispersive high resolution semiconductor detector with the ability to separate signals of adjacent and near-adjacent elements.1.4 This test method uses inter-element correction factors calculated from XRF theory, the fundamental parameters (FP) approach, or best fit regression.1.5 Samples containing higher concentrations than shown in Table 1 must be diluted to bring the elemental concentration of the diluted material within the scope of this test method.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6.1 The preferred concentrations units are mg/kg for vanadium and nickel.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.