CRUDE OIL ANALYZER

Significance of the topic

Accurate crude oil characterization underpins efficient refinery operation, precise fractionation and maximized product yield. Crude oils exhibit an extensive boiling point range and variable properties that challenge standard analytical approaches. Combining detailed hydrocarbon processing analysis (DHA) with simulated distillation (SIMDIS) delivers a comprehensive boiling point distribution, enabling refiners to optimize cut-point intervals and meet strict product specifications.

Objectives and study overview

The primary goal is to merge DHA Front End (FE) data for light hydrocarbons (up to C9) with high-temperature SIMDIS results for heavier fractions (>C9). This approach addresses recovery losses and precision issues associated with CS₂ quenching in SIMDIS and yields a unified true boiling point (TBP) curve for the entire crude sample. The study evaluates performance improvements in accuracy, precision and product modeling capabilities when using the combined Crude Oil Analyzer workflow.

Methodology and instrumentation

The analytical strategy involves two sequential gas chromatographic techniques:

• DHA FE: High-resolution separation of individual C₁–nC₉ components, avoiding detector quenching and ensuring accurate recovery in the light end.
• High-temperature SIMDIS: Extended boiling point profile for C10+ fractions up to >720 °C as specified by ASTM D7169.

Merging algorithms in the AC software align retention times and mass percentages, producing a seamless TBP distribution. Sample recovery is calculated using an external standard, and final data can be reported in mass% or converted to volume%.

Instrumentation used

The Crude Oil Analyzer system comprises:

• AC Analytical Controls Crude Oil Analyzer with integrated DHA FE and HT SIMDIS modules.
• Carrier gases: helium (99.999 %) and hydrogen (99.999 %) for Fast DHA options.
• Detector gases: hydrogen (99.999 %) and air for FID operation.
• Cryogenic oven cooling by liquid nitrogen or CO₂ for high-temperature runs.
• AC software with built-in data merging, calculation routines and QC sample support.

Main results and discussion

Comparative data show that DHA FE delivers superior recovery (≈94 % up to C9) and better precision on the light end than HT SIMDIS alone. Merged TBP curves exhibit consistent mass balances across the full boiling range and reduced variability in initial fractions. This translates into more reliable cut-point determination and tighter adherence to specification windows, minimizing product giveaway.

Benefits and practical applications

Deploying the combined analysis yields:

• Complete boiling point profiles for crude oils and residues.
• Enhanced precision and accuracy in light-end fraction quantification.
• Improved refinery yield modeling and minimized penalty for off-spec streams.
• Comprehensive QC framework with certified control samples and performance monitoring.
• Compliance with industry standards for crude oil analysis.

Future trends and potential applications

Advancements may include online integration of DHA-SIMDIS workflows for near real-time crude characterization, faster cycle times through novel inlet designs, coupling with mass spectrometric detection for compositional insights, and extension to bio-derived feedstocks. Machine learning algorithms may further refine cut-point predictions and dynamic process control.

Conclusion

The hybrid Crude Oil Analyzer approach effectively overcomes the limitations of standalone SIMDIS by incorporating DHA FE for precise light-end analysis. The merged TBP distribution enhances crude evaluation, supports accurate refinery modeling and strengthens quality assurance, resulting in economic and operational benefits.

Reference

• ASTM D7169: High-temperature gas chromatography simulated distillation of crude oils and residues.
• IP 545, IP 601 and EN 15199-3: International standards for crude oil boiling point distribution analysis.