The agenda for the meeting of ASTM Subcommittee D02.J on Aviation Fuels held in June 2008 is geared to the pertinent discussions concerning aviation turbine fuels and aviation gasoline, since there is much interest for the approval of biomass-produced fuels that would help reduce key greenhouse gases such as carbon dioxide (CO2). In addition to these topics, task force meetings were held to discuss alternate aviation gasoline, improvements and additions to ASTM Manual 5, Aviation Fuel Quality Control Procedures. A short workshop to discuss robustness of the current fuels specifications also took place. It is worth noting that ASTM International does not approve new aviation fuel formulations. This type of regulatory compliance remains in the realm of the FAA and the aircraft original equipment manufacturers (OEMs). ASTM does recognize, however, aviation approvals by incorporating them into specifications. ASTM subcommittees and task forces also serve the function of assembling diverse expertise to advise approval authorities of relevant issues regarding new fuel formulations.
The work done in ASTM Subcommittee D02.J is carried out in six separate sections. These sections are:
Section J01, Jet Fuel Specifications;
Section J02, Aviation Gasoline;
Section J03, Combustion and Thermal Properties;
Section J04, Additives and Electrical Properties;
Section J05, Fuel Cleanliness; and
Section J06, Emerging Fuels.
The key sections for the advancement of non-petroleum sources for aviation turbine fuel are Sections J01, J04 and J06.
Section J01 on Jet Fuel Specifications-The progress made in Section J01 includes but was not limited to:
-A description of a generic Fischer-Tropsch derived product known as synthesized paraffinic kerosine (SPK) is being developed for use in blending jet fuel at levels up to 50% (by volume). This will be balloted for inclusion in the jet fuel specification (ASTM D1655, Standard Specification for Aviation Turbine Fuels) when the supporting research report is available, estimated to be in late July 2008.
-The OEM/FAA approval process is under way to expand the definition of acceptable SPK to include hydrogenated fats and oils (HFO). In addition, work has begun to approve the co-processing (by hydro-treating) of fats and oils (that are used primarily to make diesel fuel) with petroleum crude streams that results in small amounts of components in jet fuel, but which have the same composition as typical jet fuel components (see comment below in Section J06 comments).
-Sasol (South Africa) fully synthetic jet fuel (FSJF) is expected to be balloted (between July and November) for inclusion in ASTM D1655, Standard Specification for Aviation Turbine Fuels, as soon as a final piece of documentation is complete, expected to be by mid-July 2008.
Section J06 on Emerging Aviation Fuels-Section J06 is a new start-up group. Their actions at the meeting were:
-Opened with a discussion of the current state of alternative turbine fuels. So far, synthesis gas derived hydrocarbons are the only alternative blend stream approved or nearly approved for use in jet fuel. Their approval resulted from the efforts of SASOL, which developed synthetic jet fuel blend stocks back in the 1990s and funded their approval testing. When Sasol requested approval of synthesized kerosine for blending jet fuels, this caused the industry to more fully define some of the requirements for jet fuel performance that were assumed to be present in fuels from conventional sources.
-The SASOL alternative fuels are derived from coal via Fischer Tropsch (FT) and other synthesis processes. Other synthesized paraffinic kerosines (SPK) blend stocks processed via FT from natural gas are very close to being approved (approval expected this summer).
-The current plans are for this section to help with the modification of ASTM D1655 to identify SPKs as appropriate blend stocks, and to start preparing a new specification for synthesized hydrocarbon turbine fuels, starting with blends of FT derived SPK. Based on the promising data being generated by HFO (hydrotreated fats and oils) researchers, a new task force was formed to develop an approval path for HFO derived kerosine as a jet fuel blend stream. This approval path will include assembling the technical data and testing results from the research work and determining what additional work needs to be completed. The approval process is anticipated to be relatively straightforward if the preliminary findings that HFO-derived SPK is very similar to existing FT-derived SPKs holds up to detailed examination.
-Preparation of the new specification is the work of a task force group that is part of Section J06. The task force is in the planning stages for the new alternative fuel specification. It will start with FT derived SPK blend stocks because the data supports such an approach, but it will not be limiting in that respect. The group will meet separately during July to work through the details.
-A major oil refiner presented information on their program to generate "Renewal Diesel" by hydrotreating fats and oils (co-processing) with diesel fuel. Currently the kerosine fraction that results is disqualified from jet fuel blending because it contains 1-2% of HFO-derived material, which is not aviation approved. The OEMs/FAA expect to approve this in conjunction with HFO-derived kerosine discussed above although processing control issues need to be addressed because the HFO SPK will never be isolated for a quality inspection.
Section J04 on Additives and Electrical Properties-Topics discussed included:
-During the session it was agreed to ballot for membership approval the new Standard Practice Guideline for the Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives, as a replacement for the current words in ASTM D4054 (same title). This guideline provides a framework for the qualification and approval of new fuels, including alternative fuels and new fuel additives for use in commercial gas turbine engines, and explains to the fuel supplier the requirements for initiating the approval process.
-The original engine/airframer manufacturers will consider a new fuel or additive based on an established need or benefit attributed to its use. Upon OEM and regulatory authority approval, the fuel or fuel additive may be listed in fuel specifications such as Pratt & Whitney (P&W); General Electric Aviation (GEAv) Specification; and Rolls Royce (RR) engine manuals.
-Subsequent to OEM approval and industry (ASTM) review and ballot, the fuel or fuel additive may be listed in fuel specifications such as ASTM D1655; the United Kingdom Ministry of Defense Standard 91-91; the United States Air Force Mil-DTL-83133; and the United States Navy Mil-DTL-5624. This qualification and approval process has been coordinated with airworthiness and certification groups within each company, the Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA).
For more detailed information on the discussions held at the D02.J meeting, contact Stanford Seto, Belcan Corp., Cincinnati, Ohio (phone: 513-985-7530; stan.seto@belcan.com). For committee and membership information, contact David Bradley, Technical Committee Operations, ASTM International (phone: 610-832-9681; dbradley@astm.org). For more information about ASTM International Committee D02, visit www.astm.org/COMMIT/D02.htm.