ASTM D7371-14(2022)

Overview

ASTM D7371-14(2022) is the internationally recognized standard test method for the determination of biodiesel content-specifically, fatty acid methyl esters (FAME)-in diesel fuel oil. Developed by ASTM International, this method uses mid-infrared spectroscopy (FTIR-ATR-PLS method) to accurately quantify FAME concentrations ranging from 1% to 20% by volume. The procedure is reliable for quality control during the production and distribution of diesel fuel and biodiesel blends.

FAME biodiesel serves as a value-added blending component, and monitoring its content in fuel blends is critical for meeting regulatory, performance, and environmental requirements.

Key Topics

• Principle of the Method: Utilizes Fourier Transform Infrared Spectroscopy (FTIR) with Attenuated Total Reflectance (ATR) and Partial Least Squares (PLS) calibration to measure the absorbance specific to FAME in diesel fuel.
• Applicable Range: Designed for blends containing 1.00% to 20.00% biodiesel by volume; with suitable accessories, the range can be extended, though with unverified precision above 20%.
• Specificity: The method specifically detects FAME; the presence of fatty acid ethyl esters (FAEE) can introduce negative bias, underscoring the method’s selectivity.
• Sampling and Calibration: Relies on representative samples, accurate calibration with reference standards, and systematic quality checks to ensure consistent results.
• Quality Assurance: Regular instrument calibration, qualification procedures, and statistical quality control are integral to maintaining measurement accuracy.
• Safety and Compliance: Users must follow appropriate safety, health, and environmental practices, in line with regulatory requirements.

Applications

• Quality Control in Fuel Production: Essential in verifying FAME content during the blending of biodiesel with petroleum diesel, ensuring batches meet product specifications.
• Distribution Assurance: Supports monitoring at various stages of distribution to maintain fuel integrity from refinery to end-user.
• Regulatory Compliance: Enables producers and distributors to comply with international, national, or regional mandates for biodiesel content in fuel.
• Performance Monitoring: Used by laboratories, fuel refiners, and regulatory bodies to ensure engine compatibility, performance, and adherence to emissions standards.
• R&D and Product Development: Applied in research and development for new diesel fuel formulations and for comparison of different biodiesel feedstocks.

Related Standards

• ASTM D6751: Specification for biodiesel fuel blend stock (B100) for middle distillate fuels.
• ASTM D7467: Specification for diesel fuel oil, biodiesel blend (B6 to B20).
• ASTM D975: Specification for diesel fuel oils.
• ASTM D4052 / D1298: Test methods for density and relative density measurements, important for converting FAME mass to volume.
• ASTM D4057 / D4177: Practices for manual and automatic sampling of petroleum and petroleum products.
• ASTM E168 / E1655: Standards for general techniques and practices in infrared quantitative analysis and multivariate calibration.
• ASTM D6299: Practice for applying statistical quality assurance and control charting to evaluate analytical measurements.

Practical Value

• Accuracy and Efficiency: The FTIR-ATR-PLS method provides fast, accurate determination of FAME biodiesel content, facilitating efficient fuel quality monitoring.
• Adaptability: Suitable for a range of diesel fuel blends and accommodates a variety of feedstocks compliant with established specifications.
• Cost-Effective: Non-destructive and requires minimal sample preparation, reducing operational costs for fuel laboratories.
• Supports Sustainability: Helps in verifying the use of renewable biodiesel components in fuel blends, aiding compliance with sustainability and environmental targets.

By adopting ASTM D7371-14(2022), fuel producers, distributors, and testing laboratories ensure reliable and consistent biodiesel content determination, supporting product quality, regulatory compliance, and market confidence in biodiesel-blended diesel fuels.