ASTM D7974-21 PDF

Overview

ASTM D7974-21 is the Standard Test Method for the Determination of Farnesane, Saturated Hydrocarbons, and Hexahydrofarnesol Content of Synthesized Iso-Paraffins (SIP) Fuel for Blending with Jet Fuel by Gas Chromatography. Published by ASTM International, this standard provides a reliable procedure for analyzing the key components of SIP fuel, which are increasingly blended with conventional jet fuel. The method utilizes gas chromatography to accurately quantify the mass percentage of farnesane (an iso-paraffin), saturated hydrocarbons, and hexahydrofarnesol in SIP fuel, supporting compliance with purity and performance requirements for aviation fuel blending.

Key Topics

• Quantitative Analysis by Gas Chromatography: The standard specifies a method for determining farnesane (2,6,10-trimethyldodecane), saturated hydrocarbons, and hexahydrofarnesol within SIP fuel, using a gas chromatograph equipped with a flame ionization detector.
• Purity Assessment: Ensures SIP fuel meets jet fuel blending specifications, including:
  • More than 97% farnesane by mass
  • More than 98% saturated hydrocarbons by mass (including farnesane)
  • Less than 1.5% hexahydrofarnesol by mass
• Mass Percentage Range: Farnesane content can be determined from 96% to 99.9%, saturated hydrocarbons from 97% to 99.9%, and hexahydrofarnesol from 0.02% to 2%.
• Main Impurity Detection: While the method identifies primary groups of impurities, it does not comprehensively catalog all potential minor or trace components in SIP fuel.
• Limitations: The method is not suitable for impurities boiling above 460°C or substances not responsive in flame ionization detection.

Applications

• Quality Control in SIP Fuel Production: Used by manufacturers to confirm that synthesized iso-paraffins meet required purity and composition specifications before being blended with jet fuel.
• Aviation Fuel Blending: Supports compliance with ASTM D7566, the specification for aviation turbine fuel containing synthesized hydrocarbons, by assuring regulated content of farnesane, saturated hydrocarbons, and hexahydrofarnesol.
• Regulatory and Safety Assurance: Provides analytical data necessary for regulatory submission and ensures the safety, performance, and environmental compliance of blended jet fuels.
• Analytical Laboratory Use: Standardizes procedures for laboratories performing gas chromatography on SIP fuels, ensuring reproducibility and comparability of results across the industry.

Related Standards

• ASTM D4057 – Practice for Manual Sampling of Petroleum and Petroleum Products: Guides sampling techniques necessary for obtaining representative SIP fuel samples.
• ASTM D4307 – Practice for Preparation of Liquid Blends for Use as Analytical Standards: Describes blending practices for accurate analytical calibration.
• ASTM D7566 – Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons: Sets forth criteria for the blending of SIP fuels into commercial jet fuel.
• ASTM E355 – Practice for Gas Chromatography Terms and Relationships: Defines chromatographic terminology relevant to this test method.
• ASTM E594 – Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography: Outlines procedures for verifying detector performance.

Practical Value

Implementing ASTM D7974-21 ensures that SIP fuels are consistently produced and assessed to meet stringent jet fuel blending requirements, supporting both fuel quality and aviation safety. The use of this test method helps manufacturers, testing laboratories, and fuel suppliers maintain regulatory compliance and optimize the performance of aviation fuels through precise analytical measurement.

Keywords: ASTM D7974-21, SIP fuel, farnesane, saturated hydrocarbons, hexahydrofarnesol, gas chromatography, jet fuel blending, aviation fuel analysis, ASTM standards, fuel purity testing.