ASTM D7806-12 for Biodiesel in Petroleum-based Diesel Fuel Oil

Význam tématu

Biodiesel blending into petroleum diesel offers renewable fuel benefits but can lead to engine compatibility, microbial growth, and oxidative instability issues. Reliable quantification of fatty acid methyl ester content in diesel is critical for quality control, regulatory compliance, and safeguarding performance of stationary and mobile diesel engines.

Cíle a přehled studie / článku

This application note demonstrates the implementation of ASTM D7806-12 using Agilent 4500, 5500, and Cary 630 FTIR spectrometers to accurately measure biodiesel concentrations from 1 to 30 volume percent. It highlights method validation, instrument performance, and software features for both laboratory and field use.

Použitá instrumentace

• Agilent 4500 Series portable FTIR with TumblIR sampling
• Agilent 5500 Series bench FTIR with DialPath sampling
• Agilent Cary 630 compact FTIR with TumblIR and DialPath accessories

Použitá metodika

Calibration standards were prepared in low, high, and ultrahigh cetane diesel check fuels covering 0–6 % and 6–30 % biodiesel ranges (18 and 30 standards respectively) plus 20 independent qualification standards. Spectra were acquired at 4 cm–1 resolution over 64 scans using 100 µm pathlength. Two linear regression models were built per cetane fuel for ester carbonyl band (1713–1784 cm–1) and ester C–O stretch (1126–1220 cm–1). Models and a cetane index predictor were integrated into Agilent MicroLab software, which automatically selects the appropriate calibration based on concentration and cetane index.

Hlavní výsledky a diskuse

All three FTIR systems achieved repeatability better than ±0.02 % versus the ±0.3 % specification. Calibration curves showed R2 values above 0.9986. Qualification tests from 1 to 30 % biodiesel yielded an average relative error of 0.62 % and maximum of 1.92 %. Below 1 % biodiesel the error increased to an average of 4.3 %. Models built separately for each cetane fuel outperformed combined‐fuel calibrations, reducing bias due to diesel aromaticity and density differences.

Přínosy a praktické využití metody

• Rapid quality control of biodiesel–diesel blends during production, distribution, and field delivery
• Portable or laboratory operation for on‐site verification of incoming fuels
• Automated, color-coded threshold reporting in MicroLab software for easy compliance checks

Budoucí trendy a možnosti využití

Future developments may include inline FTIR monitoring in fuel pipelines, enhanced chemometric models for additional biodiesel feedstocks and contaminants, integration with IoT platforms for remote diagnostics, and further miniaturization for truly handheld analysers.

Závěr

Agilent 4500, 5500, and Cary 630 FTIR spectrometers reliably fulfill ASTM D7806-12 requirements for biodiesel determination in diesel fuel. The combined hardware and software solution provides accurate, repeatable measurements across 0–30 % biodiesel, supports cetane index prediction, and offers flexible deployment in both lab and field environments.