There are few more contentious issues facing GA right now as the
question about what will eventually replace 100LL. There are few
folks working hard to address the issue, but they all report that
they're facing serious hurdles in not only perfecting their product
but wading through the bureaucratic processes necessary to make
their fuel a reality. ANN had the chance to spend some quality time
with a number of the folks behind the Swift Fuel program, one of
the more prominent players in the race to replace 100LL -- and the
conversations were intriguing -- and educational.
According to Swift Enterprises, Ltd., they have developed an
unleaded 100LL replacement fuel, called 100SF. They claim that it
exceeds the energy content and octane number of conventional 100LL.
The new fuel contains two chemical components that when mixed
together meet or exceed most performance parameters of 100LL.
Because of this, 100SF requires minimal engine modification to run
in the current general aviation fleet. 100SF does not abstract
water, which means that standard general aviation practices of
draining a sample of fuel and checking for water still hold
The components that make up 100SF are bio-derivable (sugars,
cellulose, and lignin). Using sorghum as an example, 89 gallons of
100SF can be produced from 1 ton of sorghum biomass. The fuel
contains no alcohol or oxygenates, but ethanol and ethanol plants
can be used in the production process. The uniqueness of this
approach is the fact that the Swift process does not produce
alcohol, but rather hydrocarbons already present in petroleum
fuels, from biomass.
The existing infrastructure of the bio-ethanol industry can be
used to produce 100SF; the major process equipment is the
same.100SF can be produced from any organic matter that contains
sugars or cellulose components. The components derived from biomass
are reacted to form pure hydrocarbons. 100SF is comprised of two
specific hydrocarbon components which ensure 100SF constancy from
batch to batch.
Chemical production is the defining step in the overall program.
The laboratory syntheses of these compounds have been verified and
this data has been used to construct a pilot plant. Concurrently,
engine tests have been run, and will continue to be run, to verify
the performance, safety, emissions, and long term stability
parameters of 100SF. The general aviation fuel market is estimated
at 350,000,000 gallons per year. Ten small plants, distributed
around the United States, would cover the general aviation market,
and assure a stable price. Projected costs are below current
production costs for petroleum due to the lower number of process
steps and the independence on biomass “type.”