CNS SIMDIS ANALYZER for CRUDE OIL

Importance of the Topic

Monitoring sulfur, nitrogen and carbon distributions in crude oil is essential for modern refining operations. Precise profiling of these elements supports compliance with stringent environmental regulations, prevents catalyst deactivation, and guides optimization of product cutpoints to maximize economic returns.

Goals and Overview

This study presents a comprehensive solution for rapid crude oil characterization. The CNS SIMDIS Analyzer integrates simulated distillation (SIMDIS) with chemiluminescence detection to deliver simultaneous boiling point distributions of hydrocarbons, sulfur and nitrogen from a single analysis. The system aligns with established ASTM SIMDIS methods, offering a faster and more cost-effective alternative to traditional assays.

Methodology and Instrumentation

The approach combines gas chromatography with three detectors:

• Flame ionization detector (FID) for hydrocarbon boiling point distribution
• Sulfur chemiluminescence detector (SCD)
• Nitrogen chemiluminescence detector (NCD)

Optional integration with a Detailed Hydrocarbon Analysis (DHA) front end extends coverage of light ends (C9 and below). Dedicated software automates calibration, validation, sample injection and data reporting.

Main Results and Discussion

A single CNS SIMDIS run yields three chromatograms and delivers quantitative boiling point distributions for carbon, sulfur and nitrogen. Key performance metrics include:

• Recovery of 94.3 % across the full boiling range (IBP to 700 °C)
• Detection limits below 50 ppm for sulfur and nitrogen
• Linear dynamic range exceeding four orders of magnitude
• Repeatability and equimolarity better than 10 % RSD

Post-column venting in the high-temperature configuration prevents heavy residue build-up and protects detectors.

Benefits and Practical Applications

The integrated analyzer enables:

• Rapid crude assays and refined-product QC in minutes instead of days
• Data outputs including mass-% and volume-% distributions, recovery calculations and user-defined cutpoints
• Seamless alignment with ASTM D2887, D6352, D7500, D7169 and D7807 methods
• Reduced labor, solvent use and overall cost of ownership

This capability supports refiner decision-making for blend optimization and regulatory reporting.

Future Trends and Potential Uses

Anticipated developments include further automation, expansion to additional heteroatom targets, on-line process monitoring, and integration with predictive analytics. Advances in detector sensitivity and miniaturized GC platforms may enable field-deployable crude assays.

Conclusion

The CNS SIMDIS Analyzer delivers a fast, accurate and cost-effective solution for comprehensive crude oil characterization. By combining SIMDIS with chemiluminescence detection and user-friendly software, it streamlines quality control workflows and enhances refinery profitability.

Used Instrumentation

• Agilent 8890 Gas Chromatograph configured with CNS SIMDIS modules
• Sulfur and Nitrogen chemiluminescence detectors
• Flame ionization detector
• Optional DHA front-end fractionation module
• Dedicated SIMDIS software for calibration, control and reporting

Reference

PAC L.P. CNS SIMDIS Analyzer Application Note, PAC LP, Houston, TX, Rev. 1-01/20