Metals in Crude and Resid as per ASTM D8252
Scope
The analysis of nickel, vanadium and iron in crude and residual oil as per ASTM D8252 is demonstrated. The measurement also includes the analysis of sulfur complying with ASTM D4294.
Background
The quality and grade of crude oil in part depends on the metal content as well as the sulfur content. Nickel and vanadium are the critical metals, as well as iron in some crudes and in residual oils and the metal content is especially important in the quality of bunker fuels. ASTM D8252 addresses the need to measure low levels of nickel and vanadium in crude to meet the NYMEX/CME specifications for light sweet crude oil futures contract concerning maximum allowable levels the Ni and V.
To meet the needs of the industry, Rigaku offers the NEX CG, a simple, versatile, an EDXRF analyzer ideally suited for the analysis of sulfur and metals in crude, residual oil and marine fuels. The NEX CG uses full 90o Cartesian Geometry Polarization monochromatic excitation giving superior light element performance as well as the metals.
Model: NEX CG
Units
1 ppm = 1 mg/kg
Calibration
Empirical calibrations were built using a suite of 12 commercially available calibration standards. A summary of the empirical calibrations is shown here.
| Element | Concentration range |
| Ni | 3 – 50 ppm |
| V | 3 – 50 ppm |
| Fe | 3 – 50 ppm |
| S | 0.100 – 5.000 mass% |
Repeatability (Precision)
To demonstrate repeatability, samples were measured in static position for ten repeat analyses with typical results shown below.
| Sample: Std 10 | ||||
| Element | Standard value | Average value | Std dev | % Relative dev |
| Ni ppm | 51 | 49.8 | 0.5 | 1.0 |
| V ppm | 5.0 | 5.43 | 0.29 | 5.8 |
| Fe ppm | 10.0 | 10.6 | 0.6 | 5.7 |
| S mass% | 4.501 | 4.470 | 0.010 | 0.2 |
| Sample: Std 12 | ||||
| Element | Standard value | Average value | Std dev | % Relative dev |
| Ni ppm | 30 | 30.5 | 0.6 | 2.0 |
| V ppm | 50 | 50.1 | 0.5 | 1.0 |
| Fe ppm | 5.0 | 5.03 | 0.45 | 9.0 |
| S mass% | 0.250 | 0.252 | 0.001 | 0.4 |
| Sample: Std 3 | ||||
| Element | Standard value | Average value | Std dev | % Relative dev |
| Ni ppm | 5 | 5.05 | 0.23 | 4.6 |
| V ppm | 30 | 30.3 | 0.4 | 1.3 |
| Fe ppm | 40 | 41.4 | 0.7 | 1.8 |
| S mass% | 1.000 | 0.986 | 0.002 | 0.2 |
ASTM D8252-19
In ASTM little r is called repeatability and represents the precision of the measurement. Little r is 2.77 times the 1σ standard deviation precision of repeat measurements. Comparison of NEX CG instrument r to the method r of D8252 shows NEX CG complies with the ASTM method for the measurement of Ni and V in crude and residual oil.
| Units: mg/kg (ppm) | |||||
| Element | Standard value | Average value | Standard deviation (1σ) | Instrument r | D8252-19 r |
| Ni | 5.0 | 5.05 | 0.23 | 0.64 | 1.1 |
| V | 5.0 | 5.43 | 0.29 | 0.8 | 1.0 |
Conclusion
The performance shown here demonstrates the ability of the NEX CG for the measurement of metals in crude and residual oil as per ASTM D8252 and sulfur in compliance with D4294. NEX CG is an excellent all-in-one analyzer complying with the following ASTM and US EPA test methods.
| Method | Application |
| D8252 | Vanadium and Nickel in Crude & Residual Oil |
| D4294 | Sulfur in Petroleum and Petroleum Products |
| D7220 | Sulfur in Automotive, Heating and Jet Fuels |
| EPA ULSD | Ultra-low Sulfur Diesel |
| EPA Tier 3 Gasoline | Ultra-low Sulfur Gasoline |
| D4929 Part C | Organic Chloride Content in Crude Oil |
| D5059 | Lead in Gasoline |
| D6481 | P, S, Ca, Zn in Lubricating Oils |
| D7751 | Mg, P, S, Cl, Ca, Zn, Mo Additive Elements in Lubricating Oils |
Contact Us
Whether you're interested in getting a quote, want a demo, need technical support, or simply have a question, we're here to help.