Improvements in the Process of and Apparatus for Extracting Oil from Seeds or other suitable Oil-containing Substances by Means of Solvents.
Year: 1899

page_text: Date of Application, 27th Apr., 1899
Complete Specification Left, 27th Jan., 1900-Accepted, 3rd Mar., 1900
PROVISIONAL SPECIFICATION.
Improvements in the Process of and Apparatus for Extracting Oil
from Seeds or other suitable Oil-containing Substances by Means
of Solvents.
We, GEORGE EDWARD DAVIS and ALFRED ROLAND DAVIS, both of 32, Blackfriars
Street, Manchester, Chemical Engineers, do hereby declare the nature of this
invention to be as follows:-
Our invention has reference to the extraction of oil from seeds (or other oil-
containing substances) which are capable of being subjected to the process of
treatment herein set forth and described, and has for its object the avoiding of
certain drawbacks which obtain more or less in all the various known processes
having for their object the extraction of oil from seeds by means of solvents such
as light petroleum or bisulphide of carbon.
When extracting oil from seeds by means of such solvents it is desirable that
the crushed seed should be disturbed as little as possible during the process of
extraction as otherwise the flour is apt to separate from the husk and pass away
suspended in the extracting medium involving considerable trouble and compli-
cation in the shape of filtering arrangements. It is further desirable that the
seed meal from which the oil has been extracted should be freed from residual
solvent in situ as its transference to a separate vessel for this purpose involves
additional complication in plant to prevent loss of solvent during such transfer.
Moreover it is desirable to dispense with the use of steam for removing the
residual solvent from the extracted seed-meal as thereby a meal of superior
quality is obtained. Finally it will be at once apparent that it is advantageous
to use the least possible quantity of solvent per unit of oil extracted provided
that this is combined with the highest possible degree of extraction. Our inven-
tion has for its object the attaining of the results indicated above as essential or
at all events highly desirable.
In carrying out our invention we employ a series of four or more vats con-
structed after the manner of the vats used for the lixiviation of black ash in the
well-known Leblanc alkali process. This construction allows the solid contents
of the vats to be treated with a liquid for the extraction of such constituents as
are soluble in that liquid in such a manner that the process is practically con-
tinuous, the vats (which are provided with false bottoms) forming a series into
one end of which fresh solvent is introduced and from the other end of which
the solvent flows away saturated to any desired extent with the soluble con-
stituents of the material undergoing extraction. The liquor connections between
the vats are such that each vat may in turn be made the first of the series and
after complete extraction may be cut off from the series and be drained as free
as practicable from residual solvent while the vat which was previously the second
now becomes the first of the series and receives the fresh solvent.
In order to remove the residual solvent with which the seed meal in the
extracted vat is still saturated even after the bulk of such residual solvent has

page_text: the crushed seed should be disturbed as little as possible during the process of
extraction as otherwise the flour is apt to separate from the husk and pass away
suspended in the extracting medium involving considerable trouble and compli
cation in the shape of filtering arrangements. It is further desirable that the
seed meal from which the oil has been extracted should be freed from residual
solvent in situ as its transference to a separate vessel for this purpose involves
additional complication in plant to prevent loss of solvent during such
transfer. Moreover it is desirable to dispense with the passing of steam through
the material from which the oil has been extracted for removing the residual
solvent as thereby a meal of superior quality is obtained. Finally it will be at
once apparent that it is advantageous to use the least possible quantity of solvent
per unit of oil extracted provided that this is combined with the highest possible
degree of extraction. Our invention has for its object the attaining of the results
indicated above as essential or at all events highly desirable.
In carrying out our invention we employ a series of four or more vats con-
structed after the manner of the vats used for the lixiviation of black ash in
the well known Leblanc alkali process.
This construction allows the solid contents of the vats to be treated with a
liquid for the extraction of such constituents as are soluble in that liquid in
such a manner that the process is practically continuous, the vats (which are
provided with false bottoms) forming a series into one end of which fresh solvent
is introduced and from the other end of which the solvent flows away saturated
to any desired extent with the soluble constituents of the material undergoing
extraction. The liquor connections between the vats are such that each vat may
in turn be made the first of the series and may after the extraction of the oil
therefrom be drained as free as practicable from residual solvent while the vat
which was previously the second now becomes the first of the series and receives
the fresh solvent while the vat which was the last becomes the last but one, and
the vat newly charged with fresh seed meal becomes the last.
In order to remove the residual solvent with which the seed meal in the
extracted vat is still saturated even after the bulk of such residual solvent has
been allowed to drain away as hereinbefore described we pass a current of hot
air through the seed meal and then conduct this same current through a suitable
cooling apparatus where it deposits the excess of solvent which corresponds to
the difference between the quantities of solvent which it is capable of holding in
the form of vapour at the higher and the lower temperatures.
In order to prevent loss of solvent the vats must be provided with tightly
fitting or sealed covers, and the air used as hereinbefore described for drying the
seed meal must be confined to a closed circuit (so that the same air is used over
and over again) and be moved by a suitable propeller passing through a suitable
heating apparatus on its way to the vats and after percolating through the seed
meal contained therein passing through a suitable cooling device on its way back
to the propeller, and so on, being alternately heated to enable it to take up
solvent and cooled to promote the deposition thereof. When all the residual
solvent is thus removed from the seed meal the atmosphere in the vat is dis-
placed by fresh air if necessary and caused to pass through a suitable scrubber
where it is brought into contact with a heavy oil and thereby freed from any
solvent vapour which it may contain.
After this the vat cover is removed the extracted seed discharged and the vat
recharged with fresh meal and connected up again with the other vats to form
the last of the series.
The solvent saturated with oil which runs away from the last vat of the series
is treated with closed or open steam or with both or with a current of air in the
manner well known for the separation of the solvent from the oil by the volatili-
sation and condensation of the former in the usual way.
It will of course be understood that we provide suitable condensers for the solvent
volatilised as above described, tanks for storing solvent and solvent mixed with

page_text: tap D4 and the liquor thus flowing over, which is solvent containing much oil in
solution, will pass away by the pipe O for further treatment. When sufficient
fresh solvent has been added to vat 1 to remove all the oil from the meal in that
vat taps C1, and D 4 are closed and tap E1 is opened. This allows the bulk of the
residual solvent remaining in vat 1 to drain away by the pipe U to a store tank
whence it is pumped to vat 2 as shortly to be described. When liquor has ceased
to drain from tap E1 this tap is closed, the air valves G 1, K1, are opened, steam
is turned into the jacket space of vat 1, and a current of hot air is caused to pass
through the meal moist with solvent remaining in the vat. The solvent held by
the meal is quickly vapourised and carried away by the air current which is first
passed through a cooler where the bulk of the solvent vapour is condensed and
then through a heating arrangement after which it is again passed through the
vat. The circulation of the air is repeated till vapour ceases to be condensed in
the cooler. The vat is of course still charged with an atmosphere containing a
good deal of solvent vapour and this is now displaced by forcing in fresh hot air.
The air displaced is cooled and passed through an oil scrubber of convenient
kind where the solvent is scrubbed out and retained by the oil. The recovery
of the solvent thus retained is an easy and well known operation which requires
no description.
any
The air valves are now closed, steam is turned off from the jacket space, the
bottom cover of the box W is removed, and the plug X is raised. This allows
the meal to fall out by its own gravity, and, even in the event of its not easily
commencing or of its ceasing to fall a very slight disturbance with a rod from
above or below or a movement of the plug X will set the material in motion.
Vat 1 is now recharged with fresh meal, the lid of A is fastened down and the
taps C4, D1, are opened. The last runnings of solvent which were drained off
from vat 1 by tap E 1 are now pumped on to the top of vat 2 and after this fresh
solvent is admitted to vat 2 by tap B2. While this is being done the liquor as
before is travelling from the bottom of each vat to the top of that next in series
and is finally overflowing by tap D1 to the saturated solvent main. When the
contents of vat 2 are freed of oil taps B2, C2, are closed, the vat is drained by
tap E2, and when this has in turn been closed the air valves G2, K2, are opened
and the same process of removing the residual solvent is performed that we have
already described in reference to vat 1. When vat 2 has been dried, emptied,
and recharged it becomes in its turn the last of the series so that while fresh
solvent is running into vat 3 by tap B3 the liquor is passing from vat 3 to vat 4,
from vat 4 to vat 1, from vat 1 to vat 2, and away from vat 2 as
saturated with oil, by tap D2 to the main O. In due sequence vats 3 and 4 and
then again vats 1, 2, and so on become the last of the series and a complete cycle
of operations is maintained.
solvent
From the above description it will be readily perceived that while any particular
vat is undergoing draining, drying, emptying and recharging, the lixiviation
process may be going on quite independently in the remaining three vats, and as
the number of vats in the series is only limited by convenience it is evident that
the lixiviation process can be made continuous by always having a newly charged
vat ready to put into series.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. The combination of operations forming the process as hereinbefore described
consisting in treating seed meal or other oil-containing substances in a series of
lixiviating vats so constructed, disposed, and connected that liquor can be run
from the lower part of any one vat to the upper part of the vat next in series,
and that all the vats can in turn be made to occupy the same position in relation
to the other members of the series or cycle of operations performed therein, and