Mon 4 July 2011 – Fuel standards body ASTM International has passed specifications for the commercial and military use of renewable jet fuels produced from vegetable oil-containing feedstocks such as algae, camelina or jatropha, and also from animal fats. A newly issued ASTM D7566-11 spec allows a 50 per cent blending of fuels derived from hydroprocessed esters and fatty acids (HEFA) with conventional petroleum-based jet kerosene. Last week, KLM became the first airline to take advantage of the landmark certification by operating a scheduled flight between Amsterdam and Paris using a blend based on used cooking oil sourced from the United States (see story). The ASTM subcommittee responsible for alternative jet fuel certification, which approved Fischer-Tropsch synthesis fuels two years ago, will now turn its attention to approving fuels derived from sugars, alcohols and some other synthetic technologies.
The certification is the result of years of intensive work by the D02.J0 subcommittee, which consists of more than 2,000 members from 66 countries, and a successful ballot a few weeks ago on final approval. Representatives from companies across the fuel supply chain plus HEFA fuel producers, aircraft and engine manufacturers, and regulatory agencies were involved in the process.
“The revision of D7566 reflects an industry cooperative effort to accomplish this task,” said Mark Rumizen of the US Federal Aviation Administration (FAA), who helped lead the work and is head of the certification-qualification group for the Commercial Aviation Alternative Fuels Initiative (CAAFI). “Because of the great emphasis on safety when you’re dealing with aviation fuel, the passage of this ballot required a collaborative effort between the members of the aviation fuels community.”
Aviation fuel producers, distributors, airport fuel farms and airlines throughout the world will use the standard to verify fuel quality and performance by testing to the D7566 specification requirements for components such as thermal stability, distillation control and trace material amounts.
After blending, new lubricity, distillation and composition requirements in D7566 must also be met. As a result, notes Rumizen, the blended jet fuel is essentially identical to hydrocarbons found in conventional fuel. However, the absence of natural aromatics from HEFA fuels, which are present in conventional petroleum-based fuels and essential to the safe operation of aircraft turbine engines, necessitates for the time being no more than a 50% usage of bioderived fuels in blends. Research is underway to find if synthetic aromatics could be developed to allow for higher blend mixes.
The new D7566 ‘drop-in’ fuels should be able to be seamlessly integrated into the distribution infrastructure and onto certificated aircraft as they will meet the requirements of the D1655 standard for aviation turbine fuels, which has been in industry use over many decades.
Commenting on the HEFA certification, CAAFI Executive Director Richard Altman said: “We congratulate the hundreds of aviation sponsors, biofuel producers and agricultural stakeholders on this great achievement. The leadership, focus and dedication of this team of professionals has resulted in the qualification of now two new non-petroleum fuel processes within the last 24 months. The gateway is wide open to broad deployment of sustainable, secure, and economical jet fuels that will benefit our industry, the flying public and the world at large in more ways than we could ever imagine.”
Shell Aviation’s aviation fuels technology manager, Rob Midgley, who is also a D02 member, said the D7566 revisions would help better define approval pathways for other renewable blends in which the industry was showing interest.
According to Altman, amongst the fuels that await approval are from advanced processes that use alcohols (for example from companies such as Gevo and LanzaTech), pyrolysis oil and synthetic biology (for example Amyris). “These are the subject of intensive R&D and are progressing through the Fuel Readiness process,” he said.
“These various pathways could produce outcomes in the 2013 to 2015 timeframe. As flight programmes are indicated in the 2012 to 2014 period it is clear that sufficient quantities of these fuel types will be available and the track record we have now demonstrated supports the goals we set several years ago in this regard.”
Rumizen explains that two groups are currently actively engaged in the ASTM process: the Alcohol to Jet (ATJ) Task Force and the Direct Sugar to Hydrocarbon (DSHC) Task Force. He says several companies are participating in the ATJ Task Force involving processes that utilise sugars, starches or lignocellulosic (woody biomass) feedstocks.
It’s too early to project dates on when jet fuels from these processes could be approved, Rumizen told GreenAir. “I will say that we expect to start seeing data from both task forces before the ASTM meeting. After analysing the data, we will have a better idea of how long it will take.
“A third pathway is also beginning to engage on processes involving pyrolysis and High Temperature Fluid Catalytic Cracking that start from woody biomass. So we expect to be very busy at ASTM over the next couple of years.”
This article was updated 5 July 2011
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