Determination of RON, aromatics, benzene, olefins, and density in reformate by NIRS

Significance of the Topic

The catalytic reforming process generates high-octane reformate essential for premium gasoline blends and petrochemical feedstocks. Rapid, multiparameter quality control is critical to meet regulatory and production requirements.

Objectives and Study Overview

This study evaluates the Metrohm DS2500 Liquid Analyzer for simultaneous determination of research octane number (RON), aromatic content, benzene levels, olefin content, and density in reformate using near-infrared spectroscopy.

Methodology and Instrumentation

507 reformate samples covering a broad range of properties were analyzed in transmission mode over 400–2500 nm at 35 °C using 8 mm disposable vials. Spectral acquisition and multivariate model development were conducted with Vision Air Complete software.

Used Instrumentation

• Metrohm DS2500 Liquid Analyzer (400–2500 nm)
• DS2500 Holder for 8 mm vials
• Vision Air 2.0 Complete software

Main Results and Discussion

Calibration models yielded high figures of merit for all parameters:

• RON: R² = 0.996, SEC = 0.34, SECV = 0.36
• Aromatics: R² = 0.999, SEC = 0.88 vol%, SECV = 0.91 vol%
• Benzene: R² = 0.984, SEC = 0.066 vol%, SECV = 0.088 vol%
• Olefins: R² = 0.982, SEC = 0.71 vol%, SECV = 0.87 vol%
• Density: R² = 0.993, SEC = 0.0029 kg/L, SECV = 0.0034 kg/L

Benefits and Practical Application

NIR spectroscopy provides results within one minute without sample preparation, significantly reducing analysis time, chemical consumption, and waste generation compared to conventional methods (CFR engine tests and gas chromatography).

Future Trends and Opportunities

Integration with automated sampling systems, extension to other hydrocarbon matrices, and continued enhancement of chemometric models will further improve throughput and robustness in production environments.

Conclusion

The Metrohm DS2500 Liquid Analyzer offers a reliable, fast, and reagent-free alternative for comprehensive reformate quality analysis, supporting efficient process control and compliance in fuel production.