Renewable fuels can now be blended with conventional commercial and military jet (or gas turbine) fuel through requirements in the newly issued edition of ASTM D7566-11, Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons. The revised standard was approved 1 July 2011. (Earlier post.)
Through the new provisions included in ASTM D7566, up to 50% bio-derived synthetic blending components can be added to conventional jet fuel. These renewable fuel components, called hydroprocessed esters and fatty acids (HEFA), are identical to hydrocarbons found in jet fuel, but come from vegetable oil-containing feedstocks such as algae, camelina or jatropha, or from animal fats called tallow. The standard already has criteria for fuel produced from coal, natural gas or biomass using Fischer-Tropsch synthesis.
Subcommittee D02.J0 on Aviation Fuels in ASTM International Committee D02 on Petroleum Products and Lubricants, which consists of more than 2,000 members representing 66 countries, revised the D7566 standard. Mark Rumizen, who helped lead the work to revise the specification, heads the certification-qualification group for the Commercial Aviation Alternative Fuels Initiative (CAAFI), a coalition that seeks to enhance sustainability for aviation by promoting the use of alternative jet fuels.
The revision of D7566 reflects an industry cooperative effort to accomplish this task. Because of the great emphasis on safety when you’re dealing with aviation fuel, the passage of this ballot required a collaborative and cooperative effort between the members of the aviation fuels community.—Mark Rumizen
Representatives from companies across the fuel supply chain plus HEFA fuel producers, aircraft and engine manufacturers, and regulatory agencies were involved in the specification development and revision.
Aviation fuel producers, distributors, airport fuel farms and airlines in the global aviation community will use the standard to verify fuel quality and performance by testing to the D7566 specification requirements. With this new edition, D7566 includes new, specific requirements for the bio-derived synthetic fuel component such as thermal stability, distillation control and trace material amounts.
After blending with conventional jet fuel, new lubricity, distillation and composition requirements in D7566 must also be met. As a result, the blended jet fuel used in the airplane is essentially identical to conventional jet fuel and does not differ in performance or operability, notes Rumizen.
The revised specification references numerous other ASTM standards, including tests that measure various properties of fuel. D7566 fuels also meet the requirements of ASTM D1655, Specification for Aviation Turbine Fuels, which has been used by the aviation community for decades for the quality control and distribution of conventional aviation turbine fuel. This allows these new D7566 fuels to be seamlessly integrated into the distribution infrastructure and onto certificated aircraft as D1655 fuels.
The revisions to D7566 are significant in also helping better to define the path to approval for other renewable blend components; components in which the aviation industry is already showing interest to help support the demand for sustainable growth.—Rob Midgley, technology manager, aviation fuels, for Shell Aviation, and member of D02
ASTM also has a task force looking into alcohol-to-jet pathways. (Earlier post.)