Quality control of fuels (gasoline, diesel, kerosene)

Importance of the Topic

Fuels such as gasoline, diesel and kerosene play a critical role in transportation and industry.
Ensuring their quality at production and distribution stages is essential for performance, safety and regulatory compliance.

Objectives and Overview

This study outlines a turnkey Near Infrared Spectroscopy (NIRS) solution for rapid, multi-parameter quality control of fuels according to ASTM D6122.
It presents pre-calibration models built on extensive real-product spectral data, system components and an intuitive user interface designed for non-specialist operators.

Methodology and Instrumentation

The approach uses a DS2500 Liquid Near-infrared Analyzer equipped with pre-calibrations and Vision Air software.
Key features:

• Non-destructive, reagent-free analysis
• No sample preparation required
• Measurement time under 30 seconds
• Simultaneous determination of multiple chemical and physical parameters

Used Instrumentation

• DS2500 Liquid Analyzer
• DS2500 Holder for 8 mm disposable vials
• Vision Air software
• DS2500 Liquid Wavelength Standard
• 8 mm disposable vials

Main Results and Discussion

The pre-calibration models achieve high accuracy and reproducibility across key fuel parameters:

• Gasoline: RON (81–100, SECV 0.68, R² 0.958), MON, anti-knock index, aromatics, benzene, density, olefins and oxygen (R² up to 0.994)
• Diesel: Cetane index (46–77, SECV 0.62, R² 0.987), cetane number, density, cold filter plugging point, T95 distillation cut, flash point and viscosity (R² ≥ 0.91)
• Kerosene: Cetane index, API gravity, aromatics, distillation cuts (T10/T20/T50), density, flash and freeze points, hydrogen content and saturates with strong correlation coefficients

Analysis time is reduced by more than 15 minutes compared to reference methods, with results in under one minute.

Benefits and Practical Applications

• Rapid, cost-efficient at-line or QA/QC testing without chemicals
• User-friendly operation via an intuitive software interface
• Clear pass/fail mode for shift operators and full data control for authorized users
• Minimal environmental and health impact due to non-destructive analysis

Future Trends and Possibilities

Custom calibration updates with customer-specific samples can enhance performance and extend parameter coverage (e.g., acidity, moisture).
Integration with digital lab management and real-time remote monitoring will streamline workflows.
Advances in spectral databases and machine learning promise further improvements in predictive accuracy and process control.

Conclusion

The Metrohm pre-calibrated NIRS solution delivers rapid, accurate, multi-parameter fuel quality control without reagents, supporting efficient decision-making in production, storage and testing environments.

Reference

Metrohm AG. Quality control of fuels (gasoline, diesel, kerosene): Fast results with NIR pre-calibrations. Application Note 8.929.5003EN, June 2020.