Online process monitoring of octane number during catalytic reforming

Significance of the Topic

The octane number is a critical quality parameter in fuel production, reflecting resistance to auto-ignition and engine knocking. High-octane reformate enhances gasoline performance and refinery profitability. Implementing real-time monitoring safeguards product quality, optimizes catalytic reforming operations, and reduces operational costs while maintaining stringent safety standards in hazardous environments.

Objectives and Study Overview

This application note demonstrates an online near-infrared spectroscopy (NIRS) approach for continuous measurement of research octane number (RON) and motor octane number (MON) in reformate streams. The goal is to comply with ASTM D2699 and D2700 standards, deliver rapid results, and enable swift process adjustments during catalytic reforming.

Methodology and Instrumentation

Samples are drawn from reformer outlets, passed through a preconditioning panel to remove solids and stabilize temperature, and sent to a flow-through cell. A Metrohm NIRS XDS Process Analyzer – MicroBundle (9 channels) collects spectra every 30 seconds. The system operates in ATEX/Class 1 Div 1/2 zones and communicates RON/MON readings to a PLC or DCS via common industrial protocols.

• Primary method calibration: Cooperative Fuel Research (CFR) engine per ASTM D2699/D2700
• NIR spectra acquisition: 9 probe/flow-cell channels up to 35 m from analyzer
• Data transfer: Real-time output to logic/control systems

Key Results and Discussion

Calibration models achieved high accuracy and precision across typical reformate ranges:

• RON range 90–107, SECV 0.27, precision 0.01
• MON range 80–100, SECV 0.15, precision 0.01
• ASTM accuracy: ±0.9 RON at 103, ±1.2 MON at 96

These metrics confirm that inline NIRS meets or exceeds laboratory engine test performance, delivering reliable octane values within seconds. Continuous monitoring revealed process fluctuations tied to feedstock changes and catalyst activity, enabling immediate corrective actions.

Benefits and Practical Applications

Implementing online NIRS for octane measurement offers:

• Enhanced product quality control and yield optimization
• Faster return on investment through reduced lab analysis time
• Improved safety by minimizing manual sampling in hazardous areas
• Automated detection of process upsets and feed variability

Future Trends and Potential Applications

Advancements may include:

• Integration of machine learning for predictive maintenance and advanced calibration updates
• Expansion to additional fuel properties (e.g., density, aromatic content) in a single measurement
• Remote diagnostics and cloud-based monitoring for distributed refinery networks
• Digital twin implementations for end-to-end process optimization

Conclusion

Online NIRS monitoring of octane number in catalytic reforming delivers fast, accurate, and continuous data, aligning with ASTM standards and improving refinery operations. The approach reduces reliance on labor-intensive engine tests, enhances safety, and supports real-time decision-making to maximize product quality and profitability.

References

• ASTM D2699: Standard Test Method for Research Octane Number of Spark-Ignition Engine Fuel
• ASTM D2700: Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel