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Патент USA US2410926

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Patented Nov; 12, 1946
v 2,410,926
UNITED STATES PATENT OFFICE
I
mm on. nnsmumc raocass
‘William A. Bush and Edward A. Lasher, Los
Angeles, 05111., assignors to California Flaxseed
Products Company, Los Angeles, Calif., a cor
.
poration of Califo
No Drawing. Application April 4, 1944,
,
Serial no. 529,551'
1
4 Claims. '(01. 2604.124)
This invention relates to a method for de-slim-'
ing fatty oils.
,
One object of the invention is to provide a
simple method for re?ning fatty oils which will
produce oil with such high purity that for many 5
.
2‘
,
a year- or more, the slimes are to some extent
still present as dispersed-colloids in the main
body of the oil, and are di?lcult to remove completely.
‘
Many methods have heretofore been proposed
purposes further‘ puri?cation processes are un
and used for de-sliming pressed fatty oils, which
necessary. Another object is to provide a method
involve treatment withstrong acids followed by
of re?ning fatty oils which produces 011 of such ‘ ‘repeated washings with large amounts of water,
purity that any subsequent bleaching treatments
and also sometimes involvingneutralization of
are greatly facilitated. Another object is to re 10 residual acid by an alkali treatment, followed by
move materials which inhibit decolorizing by
further water washings. Various salt solutions
bleaching clays. Still another object is to pro
have been used for washing oils to aid in the
vide a simple method for producing “break-free”
removal of the slimes, followed by repeated water
oil. Another object is to provide a slime-remov
washings ‘to remove the salt. All of these meth
ing process for fatty oils which requires no sub 15 ods require repeated handling of the oil, with
sequent steps of water washing.
'
signi?cant losses in oil in the form of emulsions,
and muchtime is consumed in the treatments.
- We have discovered that fatty oils maybe
readily re?ned and freed from dispersed col
' These methods seemingly merely cause the ‘slimes
loidal phosphatides and mucilaginous sus
to become less ?nely dispersed in the oil but do
pensions by mixing with the impure oils a rela 20 not greatly change their slimy or non-?ltering
tively small amount of both water and a water
character, and even after repeated washings by
soluble solid acid, followed by anaddition of a
acid solutions and with water, or with salt solu
?lter-aid material such as diatomaceous silica
tions and water, the slime‘ may not be ?ltered
powder, and subsequent separation of the puri
out so. completely as to give a "break-free” oil.
?ed oil from the residue. It is an important
It is only when the oils have settled or matured
part of this process that the amount of added
water shall be not more than will be absorbed
by very long standing, followed by'separation
from the roots, ‘by drawing on the top oil that
“break-free” oils may be produced by these older
and held by the ?lter-aid material and will thus
be separated from the oil in the ?ltering step.
methods. Av "break-free” oil in the ‘trade is one
It is also important that the solid acid shall be 30 which does not form a cloud or precipitate when
su?iciently soluble in the selected limited
heated as in varnish making or in forming heat
amount of water, at the operating temperature,'
bodied oil. The "break” material may or may "
that a strong acid solution will result, to effect
not of itself be colored, and the re?ning steps
the separation of the slime from the oil.- The
of this invention relate to removal of slime and
addition of water is necessary since solid acid
suspended matter and not directly to removal of
particles alone do not effect the desired de'sliming
color vas treatment with bleaching clays. We
It is practically impossible to remove all of
have found, however, that oils re?ned by our
the slime in pressed or expelled fatty oils by ?l
process are much more easily bleached by bleach
tration methods alone.
The'slimes are so com
pletely dispersed that they tend to pass through
the ?lter cloth for a time and then eventually
the cloth becomes blocked so that no oil can be
forced through under ordinary working pres
ing clay treatment, following the removal of
so
slimes.
.
‘
.
Our method will be understood-by the follow
ing illustrative examples.
To about 21,000 pounds of prime cold-‘pressed
sures. These conditions remain essentially-the
linseed oil, previously warmed to about 80° F.,
same even when fairly large amounts oi’ ?lter 45 was added with'vigorous stirring, a solution of 6
aid powder are added, the-?lteraid serving only
- pounds of oxalicacid crystals dissolved in three
to slightly prolong the ?ltering cycle. In any
case some slime goes through into the ?ltered oil
unless some steps are taken to change the na
ture of the slimes so that they may be ?ltered
gallons‘ of hot water. This solution was sprayed
into the vigorously agitated oil and intimately
mixed with it for a period of. 5 to .15 minutes.
About 150 pounds of diatomaceous silica ?lteraid
was then added and the vigorous stirring con
tinued for another 10 to 15 minutes, followed by
out. In practice, the freshly pressed or partly
re?ned oils are allowed to age in tanks, and the
top oil only is withdrawn for re?ning, the foots
a period of about an hour during which the stir- being left and treated separately. Unless the
ring was only enough to keep the ?lteraid sus
aging has been for quite a prolonged time, even 55 pended. The entire batch was then pumped
w
2,410,926
is required, and much less oil is lost by the emul
si?cation inherent in the processes involving large
through a plate and frame ?lter press which
had previously been pre-coated with ?lteraid.‘
All of the slime, ?lteraid, water and any precip
volumes of treating and washing liquids.
Other solid acids having su?lcient solubility to
form moderately‘ concentrated water solutions
comparable to those of oxalic acid and sultamic
acid, may be employed, for examples citric acid,
picric acid, maleic acid, etc., have been found to
itated solid acid particles if any, were retained
in the press-cake, together with a little occluded
clean oil. After the batch had been ?ltered, the
?lter press was blown with air, and the recov
ered oil added to the main batch. rlli'he linseed
be satisfactory in our process. Any solid acid
oil so produced is clear and lighter in color than
which is insoluble in the oil, and which is su?l
10
a similar oil treated by conventional methods,
ciently soluble in water to give in concentrated
and it forms no “break” when heated for heat
or saturated solution a strong aqueous acid, and
bodying or varnish making,
‘
Dark colored oils de-slimed by our process are I
at least is moderately strongly ionized, may be
used. The strong mineral acids such as sulfuric
noticeably improved in color probably by removal
and hydrochloric, are not suitable because they
of the colored suspensoids, and furthermore, the [5 combine chemically with the oil or dissolve in it,
oil is rendered much more amenable to bleach
and if used would require much waterwashing
ing by bleaching clays for subsequent reduction
to remove acidity from the ?ltered oil. We have
of color. In one case, a dark'green mustard oil,
deslimed by our process, was improved in color
successfully used sulfamic, oxalic, citric, picric
and maleic acids. These acids are insoluble in
by this process of desliming from a color of 14 to 20
fatty oils such as linseed, soy bean, mustard, pe
one of 12 on Gardner color- standards 1933 scale,
rilla, tung, sardine, and similar oils, and do not
and when subsequently further bleached by
chemically combine with this type of oil. These
heating with decolorizing clay, required only 21/2
acids range in solubility at room temperatures
percent of clay to give a bleached oil of about 8
from about 1.4 to 130 parts by weight to 100 parts
on the same color scale. ‘
Sulfamic acid maybe used in place of oxalic
acid. For example, crude linseed oil containing
three percent foots (as determined by the heated
25
of water, and have ionization con'stantsranging
from about 10*1 to 104. These acids are solids,
so that any excess acid above that which will dis
solve in the small amount of available water at
oil method, A. S. T. M. D234-28 method) in the
any stage of our re?ning process will be retained
amount of 21,000 pounds, heated to about 80° F. 30 in the ?lter cake, and therefore will not pass with
was charged into an oil re?ning kettle equipped
the re?ned oil as would excess liquid acids. Other
with variable speed stirrers. A_ solution of 6
acids having similar properties to those described
pounds sulfamic acid crystals dissolved in three a
are believed to be equivalent in our process.
gallons of distilled water was then sprayed into
In using the solid acids, we find it desirable to
the rapidly stirred batch of oil. The violent agi
dissolve the acid in the small amount of water
tation was continued for about 15 minutes, then
used in our process, using hot water if necessary.
150 pounds of diatomaceous silica ?lteraid pow
When this solution is violently mixed into the oil
der was added and the agitation continued for
batch, minute particles are dispersed throughout
?fteen more minutes. The stirring rate was then .
40 the oil, along with, in some cases, the precipitated
lowered to that required to keep the ?lteraid pow
solid particles of acid. Violent agitation of the
der in suspension, , for about an hour longer.
mixture is required in order to bring all parts of
Then the batch was ?ltered through a precoated
the oil in contact with the acid.
?lterpress; The water, ?lteraid, acid in solution
The amount of water, as previously stated, is
and as solid particles if any, and all of the slimes, _
small and is selected as an amount which will
were retained in the press, with some occluded oil 45 be absorbed by the ?lteraid employed in the ?ltra
which was blown out with air at the end of the
tion process. It is well understood that the
cycle. The “break-free” oil was of quality suita
ble for the paint trade.
Crude soy bean oil produced by pressing or
amount of ?lteraid employed in ?ltration is gen
erally determined by the amount and kind of
our process yielded a “break-free” oil from soy
bean oil, which at the same time was improved
in color from 12 to 111/2 on the Gardner Color
limits, increases the length of time that a ?lter
press may be used before the operating pressure
colloidal material to be ?ltered out as well as
expelling is usually contaminated withv higher 50 upon
an acceptable rate of ?ow of liquid through
percentages of slimes than crude linseed oil. Yet
the press. Larger amounts of ?lteraid, within
goestoo high for practical operation, but with
Standards of 1933. In one case, 21,000 pounds of 55 most types of pressure ?lter presses, this addi
the crude soy bean oil were treated as in the
tional ?lteraid powder soon ?lls up the cake
above example for linseed oil with 471/; pounds
1 space, and the cycle is shortened. On the other
of oxalic acid dissolved in 35% gallons of distilled
hand, if too little ?lteraid is used, the ?lter cloths
water. In this case 3'70 pounds of diatomaceous
become clogged with slime and the cycle of opera
silica ?lteraid were used to pick up the slimes, 00
tions is too short for economical operation. An
the acid and the water, 55 pounds of the ?lteraid
additional advantage of smaller amounts of ?lter
being used to precoat the ?lterpress. The treated
aid is the smaller amount of oil absorbed in the
oil exhibited no “break” when heated to 500° F.
?lter cake, which absorbed oil cannot all be eco
in 5 minutes.
“Bottoms” from oil storage tanks, containing as 65 nomically removed, and a smaller amount ab
sorbed means a smaller loss. An optimum quan
high as 30 percent “break" have been cleaned up
tity of ?lteraid may be selected for any set of
and puri?ed to a “break-free” oil. In one case, 42
conditions and materials which will give eco
pounds of sulfamic acid in 26 gallons of water,
nomical operation and at the same time give clear
with 1460 pounds of diatomaceous silica ?lteraid;
?ltrates. The amount of ?lteraid used by us in
in 21,000 pounds of "bottoms” treated as in the
our method has varied from 0.7 to 7.0 percent
above example for linseed oil, gave a saleable,
weight of ?lteraid based on the weight of oil
“break-free” paint oil.
treated, and the amount of water has varied from
One important advantage of our process is that
16 to 80 percent by weight of the ?lteraid. The
no water washing after desliming is required, and
amounts
of acid, ?lteraid, and water, will of
75
consequently much time is saved, less equipment
2,410,928
course, vary with the kind of oil,- the amount
We claim:
and nature of the slime. and the completeness‘
of slime removal desired, and the range of pro
prising mixing into said oil a substantially satu
portions here given is illustrative.
rated water solution of a solid acid selected from
The type of ?lteraid used by us in a processed
diatomaceous silica of the type known in the
trade as “Hy?o” and "Speedex” which are natural ' _
diatomaceous silica powders calcined with a flux
. ing material as described in U. S. Patent No.
1,502,547.
The completeness of the de-sliming process de
pends upon the amount of water, solid acid, and‘
‘
1. The process of de-sliming a fatty oil com
the group consisting of sulfamic acid, oxalic
acid, citric acid, picric acid and maleic acid in
an amount su?icient to break the slime dispersion, -
mixing into said mixture a solid ?lteraid powder
in amount su?icient to absorb all of said water
10 solution remaining after mixing with the fatty
oil, and ?ltering out said ?lteraid, acid and water
vwith the slime from the puri?ed oil.
‘
?lteraid used, and if a completely “break-free”
2. The process of de-sliming a fatty oil com
oil is desired, the larger amounts of acid and
prising mixing into said oil a substantially satu
W?lteraid may be used. For purposes where 15
rated water solution of sulfamic acid in an
“break-free” oil is not required, lesser amounts
amount su?icient to break the slime dispersion,
of acid and ?lteraid may be employed.
'
mixing into said mixture ‘a ?lteraid powder in
The temperature of the oil during our de
' sliming process is not critical but is selected to '
- amount su?icient to absorb all of said water solu—
give the required ?uidity of the oil for facility 20 tion remaining after mixing with the fatty oil,
and ?ltering out said ?lteraid, acid and water
in mixing and handling, and for shortening the
with the slime from the puri?ed oil.
time of treatment. »
3. The process of de-sliming a fatty oil com
While our process is directed to removing the
prising mixing into said- 011 a substantially satu—
colloidally dispersed and ?ne suspended mucilagi
rated water solution of oxalic acid in an amount
nous and protein materials, it usually reduces the 25 su?icientto break the slime dispersion, mixing
color slightly because these suspensoids them
into said mixture a ?lteraid powder in amount,
selves may be colored and the oil darkened there
sui?cient to absorb all of said water solutionyre
by. Therefore the oil usually is lightened by our
maining
after mixing with the fatty oil, and
process. In addition, because of the complete re
?ltering
out
said ?lteraid, acid and water with
‘moval of these extraneous materials, it is found 30 the slime from
the puri?ed oil.
that the oils so treated, when heated alone. are‘
4. The process-of de-sliming a fatty oil com
somewhat bleached, and if furtherlightening of
prising mixing into said oil a substantially satu
the color is required or desired, the oils treated,
rated water‘ solution of maleic acid in an amount
by our process are much easier to bleach by treat—
su?icient to break the slime dispersion, mixing
ment with bleaching clays, requiring shorter 35 into
said mixture a ?lteraid powder in amount
times and less clay. .
w
_
suf?cient
to absorb alllof said water solution re
It will be seen that our process has many ad
maining after mixing with the fatty oil, and
vantages because it is simple, direct, ‘requires no
after washing, gives ‘.‘break-free" oil, and a mini-, .
mum of losses of 011 during treatment. The proc 40
ess may be used on oils having excess slimes such
as tank bottoms, which do not clean up readily
by. any other known method.
' ?ltering out said ?lteraid, acid and water with
> the slime from'the puri?ed oil.
.
WILLIAM A. BUSI-L
‘EDWARD A, LASHER.
a
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