XRF Analysis in the Petrochemical Industry

Key Applications

• Sulfur in automotive fuels — Sulfur forms harmful sulfates in exhaust gases, contributes to SOx emissions, reduces fuel stability, and affects engine performance. Regulatory limits continue to decrease (e.g., ultra-low sulfur diesel <10 ppm). XRF complies with ASTM D4294 and similar standards for low-level sulfur measurement.
• Unused lubricating oils — Oils contain organo-metallic additives (detergents, antioxidants, anti-wear agents) with elements such as Mg, Si, P, S, Cl, Ca, Cu, Zn, Mo, Ba. XRF supports ASTM D6481 for P, S, Ca, Zn and extends to additional elements (Mo, Ba, Mn).
• Used lubricating oils (wear metals monitoring) — Elevated concentrations of Fe, Cu, Pb, Sn, Ni, Zn, Al, Cd, Ag, Ti, V, Cr, Mo indicate engine wear (bearings, pistons, seals, catalyst residues). XRF detects these at low ppm levels for predictive maintenance.

Instrumentation

Benchtop energy-dispersive XRF spectrometers optimized for petrochemicals typically feature:

• 40 kV Silver anode tube — minimizes line overlaps with chlorine and improves low-level Cl detection
• Large-area Fast Silicon Drift Detector (FSDD) — delivers excellent energy resolution and low detection limits
• Helium purge system — enhances sensitivity to light elements (S, Cl, P, Si)
• User-friendly software with minimal training required

These systems achieve detection limits down to several ppm for sulfur and other elements.

Measurement Method

No complex sample preparation is needed — liquid samples are simply poured into sample cells covered with thin Ultralyne film. Calibration uses certified oil standards for key elements (Si, S, Ca, V, Cr, Fe, Ni, Cu, Zn, Mo, Ba, Sn, Pb).

• Dual-range sulfur calibration: low (up to 1000 ppm) and high (0.1–5%)
• Typical measurement time: 120 seconds
• Main mode: 10 kV anode voltage, no primary beam filter

Conclusions

XRF provides strong correlation with certified values across wide concentration ranges for sulfur, chlorine, wear metals, and additives. It fully supports international standards such as ASTM D4294 (sulfur in fuels) and ASTM D6481 (additives in unused oils). With high precision, low detection limits (ppm level for S), ease of use, and cost-effectiveness, XRF is an ideal solution for routine petrochemical analysis from trace to percent levels — improving quality control, regulatory compliance, and process efficiency.