Improvements in the Naphtha Process of Extracting Oil.
Year: 1890

page_text: Date of Application, 30th Dec., 1890-Accepted, 21st Feb., 1891
COMPLETE SPECIFICATION.
Improvements in the Naphtha Process of Extracting Oil.
I, JOHN WILLIAM EVANS, of Cleveland, State of Ohio, United States of
America, Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention relates to improvements in what is known as the naphtha process
of extracting oil. In extracting oil by the naphtha process for instance from
linseed, the seed is ground and placed in a percolator and the latter is then
charged with hot naphtha as a solvent.
After a time the united oil and naphtha is drawn off at the bottom of the
percolator, or at least so much of the mixture is drawn off as will separate itself
from the meal by gravity. There will still remain in the meal more or less naphtha
and a small percentage of oil the former being distributed throughout the mass of
meal while the remaining oil will be distributed in the lower portion of the meal
near the bottom of the percolator. The discharge pipe at the bottom of the
percolator is then closed and the eduction vapour pipes are opened and live steam
is introduced into the meal in the percolator to evaporate the remaining naphtha,
the naphtha vapour being conducted to a condenser whence the liquid naphtha is
returned to its tank to be again used for extracting the oil from the next batch of
meal. A suitable percolator for carrying out this process is shown and described
in British Patent No. 5971 granted to me 21 April 1888 and to which reference is
hereby made and for convenience for reference in this Application the percolator is
outlined in the accompanying drawing the same being an elevation in section through
the centre of the percolator.
A represents the percolator B a pipe connecting with the bottom of the percolator
for drawing off the united oil and naphtha C Č are eduction vapour pipes D is a
steam pipe encircling the percolator and from which extend smaller branch pipes d
connecting respectively with the different hollow arms arranged inside the percolator
in series at different elevations at E E' and E2. These arms as shown extend
radially towards the centre of the percolator and for convenience in removing the
material these arms are mounted on hollow trunnions so that the different arms
may be folded down along side of the walls of the percolator. It is believed that
this brief description of the percolator will be sufficient for a full understanding of
my improved process.
Before filling the percolator the different hollow arms are extended and held in a
horizontal position and the valves of pipes B and C are closed. After the meal
and hot naphtha with which the percolator is charged has remained for a suitable
length of time valve of pipe B is opened to draw off the mixed oil and naphtha
and after this has been accomplished so far as gravity will effect such separation of
the oil and solvent from the meal, valve bis closed. Next the valves of pipes C
are opened and live steam from pipe D is admitted through pipes d to the hollow
arms to evaporize the naphtha remaining in the meal.
The
Heretofore steam was first admitted to the upper series of arms E by means of
which the naphtha from the upper portion of the meal was readily evaporated, the
naphtha vapour passing off through pipes C to a condenser not shown. After a
time the steam was shut off from arms E and was introduced into arms E¹.
naphtha from the central portion of the meal was evaporated and expelled more
slowly owing to the depth of material above that has been rendered more compact
by the previous steaming. Eventually the steam was shut off from arms E¹ and
admitted into the lower arms E' to evaporate the naphtha from the meal at or near

page_text: the bottom of the percolator. This last stage was much more difficult and tedious
owing to the great depth of material above and owing to the fact that the upper
portion of the meal had been rendered compact and clammy by previous steaming,
hence it was necessary to employ a higher pressure of steam for evaporizing the
naphtha and expelling the vapours thereof from the lower portion of the meal.
Another objectionable feature was that the residue of oil in the lower
portion of the meal was carried up with the naphtha vapour and distributed
beyond recovery throughout the whole mass of the meal. To more clearly
define my improved method hereinafter mentioned I will remark that the linseed
meal had from the naphtha process is considered a valuable food for animals
more especially as the albumen of the seed is left entirely in the meal and hence
the oil is pure, as the albumen if left in the oil is an impurity and has to be
subsequently removed by some process of refining to produce a good quality of
oil. Also any oil left in the meal not only deteriorates the latter but the
purchaser in buying meal by the pound does not care to pay for what is worse
than useless in the meal, to wit, the remaining oil, and the manufacturer of it
does not wish to sell oil at the price per pound of meal. It is therefore
important from both standpoints that as far as possible the highest per cent. of
oil be extracted from the meal.
In carrying out my improved method I provide an eduction vapour pipe leading
from the bottom of the percolator, such pipe being shown at C. This pipe is
more conveniently attached to pipe B as a branch of the latter, pipe C being
provided with a valve c. This is the only addition that I make and otherwise
the percolator is left in the same condition as heretofore. Of course another
condenser is provided for condensing the naphtha vapours escaping through pipe C¹.
Now in "steaming out" the naphtha, steam is admitted to the central arms E¹
and immediately after to arms E and E². The vapour from different portions of
the percolator may therefore take the shortest and easiest route whichever it
may be up or down and the lower portion of the meal in the percolator is freed
from naphtha as expeditiously as the upper portion the "steaming out" requiring
less than half the time formerly required. Also the residuum of oil that as
aforesaid is found in the lower portion of the meal is carried downward by the
escaping naphtha vapour and about all of it is thus reclaimed, the oil passing off
in the naphtha vapour through pipe C' and uniting with the naphtha condensed in
the lower condenser and no effort at the time is made to recover this oil from
the fact that the naphtha in this condenser is returned to its tank and is used
over again in the next operation and hence this oil is not lost.
To recapitulate-With my improved method, whereby the naphtha vapour may
escape simultaneously from the top and bottom of the percolator, first, a large
percentage of oil is obtained, the absence of which in the meal renders the latter
more valuable, and also is avoided the excessive cooking of the meal at the
upper portion of the percolator and the consequent wet and clammy condition of
this when removed from the percolator, and the " steaming out" process is
accomplished in less than half the time formerly required.
In conclusion I will state the fact that the percolators that I am using have
a capacity of eight hundred and twenty five bushels of meal and with my
improved method hereinbefore described I am enabled to save two barrels of oil
for each charge of a percolator more than I could save when operating the
percolators without the lower vapour pipe that is to say steaming out the naphtha
with the escape of the naphtha vapours only at the top of the percolator.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is: =
In what is known as the naphtha process of extracting oil, the method herein
described and consisting essentially of introducing steam into different portions

page_text: of the percolator, and simultaneously exhausting the naphtha vapour from the
top and bottom of the percolator substantially as set forth.
Dated this 30th day of December 1890.
HERBERT & Co.,
18, Buckingham Street, Strand, W.C., London, Agents to Applicant.