[SEL] narrow miss for my engines today...

[Kerry Morris]

> Curt
> P.S. For the Ozzies.....how do you get the oil out
> of a Eucalyptus tree?

Curt short answer distilling of the leaves, as a boy I
seen one near here, I believe most oil now is imported
(for trees originally exported).

Kerry  Lithgow Oz


Oil distillation 

The eucalyptus oil distilleries of Central Victoria
are basically the same and each has the following
components: steam supply, distilling vat(s),
connecting piping, a condenser, and an oil-collecting
vessel. In most of the stills the distilling equipment
is antiquated and no updating of this equipment is
evident. 

At the distillery, the vat containing the harvested
leaf is positioned Underneath a removable flat lid
which can be lifted completely clear of the mobile vat
for ease in loading and unloading the leaf material. 

Three evenly-spaced pipes, running longitudinally
along the floor of the vat, allow steam to be fed
through a flexible steam line at the bottom of the
vat. The steam line is fed by a spent-leaf fired
external boiler. The lid is lowered on to the vat and
tightly secured using locking clamps, and steam is
injected. One charge consists of approximately 8
tonnes of green, uncompressed leaves. Distillation
begins when the vat is full of leaves and the steam
then passes through the charge and the oil is
vaporised. The vat has a drain at the bottom which
allows for the removal of the residual black liquor
which consists mainly of tannins. 

There are three outlets for the vapour and these are
connected to one central duct in the centre of the
lid, allowing for the discharge of the oil/water
vapours during distillation. The condenser consists of
a length of pipe running from the vat to a pond. The
condensate is cooled and the condensed liquid flows
into the oil collection vessel. 

The oil collection vessel is the device for collecting
the condensed distillate and allows the separation of
the oil from the water. This consists of an open drum
partly embedded in the ground. Since the oil is
largely insoluble in water, it separates and is
scooped off the surface. The distillation process
Usually takes 3-4 hours and a typical distillery can
distill three vat loads per day. The oil is then put
into 44-gallon drums and sold in crude form for
approximately US$3 per kilo (Paul Foreman, pers.
comm., 1994). No further processing of the oil is
undertaken on site. 

Further refining of the oil is done in Melbourne. This
is done by rectification. Rectification is a more
controlled distillation process which is used either
to upgrade the oil or to isolate the major components
of the oil. The chemicals are then used as precursors
for chemical reactions or may be used as discrete
aroma chemicals. For cineole-rich eucalyptus oil,
rectification is employed to increase its market
acceptance. Cineole can also be isolated by
rectification and this is more expensive than basic
oil and it is mainly used in high quality products
(Boland et al., 1991). 




       
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