Air travel has continued to increase dramatically and all
indications are that the rapid rate, approximately 4% per annum,
will continue into the foreseeable future. One major barrier to
this growth is related to fuel. There exist major technical
challenges in supplying fuels and in reducing exhaust pollutants.
Transport propulsion is dependent on limited sources, mainly fossil
fuels, which have a peak production predicted to be around 2005,
and crude oil sources are limited and will eventually run out.
Commercial air transport is responsible for around 700 million tons
of jet-fuel derived CO₂ today, about 2.31% of total anthropogenic
carbon dioxide, future forecasts of aviation growth show CO₂
emissions from the sector rising rapidly and inexorably to more
than 1 billion tons by 2025 and this is unlikely to be acceptable.
The future rate of gains in 15-20% aviation fuel efficiency
(excluding dramatic improvement in fuel efficiency since the first
commercial turbine aircraft which entered service in the 1960s) is
not sufficient, nor likely to be matched into the future, to offset
the growth rate of air travel (about 5.3% per year between 2000 and
2007, resulting in an increase of passenger traffic of 38%)
particularly as many of the relatively easy technical improvements
have already been incorporated. Any growth in air travel will lead
to higher fuel demand. This will require the problem of meeting
fuel requirements to be addressed including crude oil availability
and cost, oil security, and concerns about global warming and
climate change. For the growth of air travel to continue fuel
alternates for aviation have to be found.
Biokerosene manufactured from vegetable oils is expected to have
similar properties to conventional kerosene. The fuel is one of the
candidates for aviation fuels due to its renewability and its
availability, and its ability to mix with the traditional fuel. The
source of materials for these is more widely, and thus reliably
available when compared with their fossilized counterparts.
Vegetable oils consist of long-chain fatty acid alkyl esters
organic compounds and can be derived from a broad variety of
renewable resources such as soybean, grape, jatropha, and algae
oils. The oils have high viscosity, high freezing points, poor
thermal stability compared to conventional kerosene, at this state,
the oils cannot be viable fuels for aviation. Therefore, the
sources of fuels need to be converted into biokerosene through
techniques like pyrolysis and hydrodeoxygenation. This paper gives
an overview of alternative aviation fuel applications, the
production of biokerosene aviation fuels, and outlines the first
stage of our efforts to develop an experimental strategy for the
manufacture of biokerosene from vegetable oil sources by pyrolysis
that could presents a solution to the fuel shortage in the
future.