ETHANOL BLENDING
The change from fuels
with an MTBE
component started as
an environmental issue in
locations such as the West
Coast USA, New York City and
Europe. With the desire to
replace the MTBE with a
renewable fuel, the natural
choice was Ethanol. The need
to blend Ethanol into
petroleum products is now
seen as a global requirement.
Whereas MTBE could be
blended in the refinery and
transported to the truck
loading terminals via pipeline
or rail car, Ethanol blended
fuel contains properties that
make this difficult. Ethanol, by
nature, will attract any H2O
encountered en-route or
found in storage tanks. If this
were to happen in a 10%
blend, and the concentration
of H2O in the blended fuel
reaches 0.4 %, the combined
Ethanol and H2O drops out of
the blend. The exact point of
drop out depends on the
Ethanol blend percentage,
makeup and product
temperature. If this drop out
occurs, the Ethanol combines
with the H2O and separates
from the fuel, and then drops
down to the bottom of the
storage tank. The resulting
blend goes out of spec.
Putting the fuel back on spec
usually requires sending the
contaminated Ethanol back to
the production plant.
The solution to this problem
is to make sure the Ethanol is
kept in a clean, dry
environment and blended with
the petroleum products as you
load the transport trucks.
Moving the blend point to the
truck loading point minimises
the risk of H2O contaminated
fuels. This solution has been
the choice of most major oil
companies as well as regional
suppliers of Ethanol blended
fuel.
As with many new
solutions, this approach
creates several new issues to
deal with.
