Improvements in the Method of Refining Oils.
Year: 1898

page_text: Date of Application, 8th Aug.. 1898-Accepted, 10th Sept., 1898
Improvements in the Method of Refining Oils.
I, MARTIN EKENBERG, of Vestra, Hauingatam, 18, Göteborg, in the Kingdom
of Sweden, Dr. of Philosophy and Engineer, 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:-
In the saponification of fatty oils, more especially in removing free fatty acid
from such oils, caustic alkalies are at present used partly dissolved in water and
partly mixed with pulverized substances, said caustic alkalies being as a rule added in
such quantity that a neutralization of the fatty acids is just accomplished. When
oils in large quantities are to be refined at once it is, however, found difficult to
separate the soaps formed by the refining agent, and by the fatty acids of the oil.
Minor quantities of fatty acids, say 0.2-1 per cent. by weight, can be removed quite
easily in the usual manner, but when the percentage is greater-for instance 4-5%,-
the soaps as a rule become so slimy that it is only with the greatest difficulty that
they separate from the oil. Moreover, in the case of some oils the separation is
made more difficult from the fact that the neutral oil is capable of physically
dissolving soaps. The said difficulties of the refining process are removed by
employing the present method which consists in adding a substance which makes the
soaps firm and prevents them from being dissolved in the oil. This substance is
glycerine which only need be added in quantities of say from 0.1 to 06% of the
weight of oil, depending on the percentage of fatty acids in the oil, always in
such quantity however, that the soaps will contain glycerine, to the amount of
from 5 to 10% of their weight.
The glycerine also communicates to the soaps the property of absorbing in a
higher degree than before the usual colouring matters and other impurities in the
oil, which impurities are precipitated with the soaps.
The method is in practice carried out as follows:-A solution of a hydrate of
an alkali in commercial glycerine is prepared and added to the oil in such
quantity that the fatty acids are neutralized. The mixture is subsequently
heated to 1000 Cent. or more while being carefully stirred firm or compact soaps then
separating and settling to the bottom. Afterwards the neutral oil may easily be
clarified by filtering. In the corresponding treatment with a hydrate of an alkali
alone, slimy soaps are formed in most cases, which soaps require a long time to
separate from the oil.
The addition of glycerine to cheaper grades of oils more especially those whose
neutral fat in saponifying secretes a large amount of glycerine, may be effected
by the saponification of a portion of said neutral fat, just sufficient to liberate the
aforesaid minimum of glycerine which is absorbed by the soaps. Free glycerine is
but rarely found in acidulous oils, and it is therefore necessary in the latter case to
saponify from 1 to 2 times as much neutral fat as fatty acid. Owing to this fact the
modified method last mentioned can be advantageously applied only in cases where
the soaps precipitated can be utilized to advantage. Also in the latter case heating to
100° Cent. or above this temperature must take place in order to cause the liberated
glycerine to act.

page_text: Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I
claim is
1. The method of refining fatty oils by means of alkalies, consisting in adding
glycerine together with alkaline hydrate heating the mixture and stirring it for the
purpose of effecting the precipitation of firm or compact soaps" which may be
easily removed by filtering.
"
2. The method of refining fatty oils by means of alkalies, consisting in adding an
alkaline hydrate to the oil in such quantity that by the saponification of neutral fat
glycerine is liberated in a quantity amounting to 5% at least of the weight of the
soaps liberated and heating and stirring mixture for the purpose of obtaining
glycerine soaps, which can then be easily separated.
Dated this 8th day of August. 1898
BOULT & WADE,
Agents for the Applicant.