Note: Descriptions are shown in the official language in which they were submitted.
~652~
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the processing of a non-
petroleum organic liquid such as fats, animal and vegetable
oils; and more particularly to the improvement in color of
such an organic liquid by a multistep treating process.
2. Description of the Prior Art
Many non-petroleum organic liquids (e.g., fats,
vegetable and animal oils) are ~sed for human consumption and
other utilizations. The organic liquid can be purified
- chemically and mechanically to remove solids and to improve
chemical properties, color, odor and enhance storage
stability, to make it more suitable for ultimate utilization.
- Present day treatment of crude fat, animal and vegetable oils~
; as organic liquids, consist generally of the steps of refining,
~,r~ bleaching, and deodorization. The term "refining" reers to
any purification treatment designed to remove undesired
materials such as free fatty acids, phosophatides, or mucil-
aginous material, or other gross impurities in the or~anic
liquid. The term "bleaching" is reserved for treatment
designed solely to reduce the color of organic liquid. The
term "deodarizing" is used for the treatment which has a~
its primary objects to remove the traces of constituents
,. ~ . .
which give rlse to flavors and odors from tbe organic liquid.
The refining of an organic liquid usually employs
aqueous reagents in the nature of alkali or acid to remove
~ertain irnpurities, such as free fatty acids and certain
color bodies. Also, the refining treatment can improve
the color and odor characteristics of the organic liquid.
For example, vegetable oils, especially those subjected to
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oxidization, suffer from increased red and yellow color
:`
components; however, the green color from chlorophyll is not
affected. In the hydrogenation of the refined organic
liquid, the organic liquid is--admixed with a small amount of
a hydrogenation catalyst in a finely dispersed state. For
example r an amount of metal hydrogenation catalyst less than
about .05~ by weight is introduced into the organic liquid.
Then, this mixture is subjected to superatmospheric hydrogen
at elevated temperatures for a~selected period of time until
the desired reaction of the unsaturated and hydrogen reducible
materials is reached in the organic liquid. After hydro-
,.. ~ .genation is completed, the organic liquid carrying thedispersed hydrogenation catalyst is passed through precoated
leaf filters for the removal of the metal hydrogenation
.- catalyst. As is apparent, the nature of filtration will
.
~; result in a small amount of the metal hydrogenation catalyst
~! .
being carried with the filtered organic liquid. In m;.!
instances, the residual amounts of metal hydrogenation
`~ catalysts must be removed by subsequent steps, which are
~ ,.,
usually termed "post bleaching", where the residual traces
of the metal hydrogenation catalyst are removed through the
:~ use of metal scavengers or compounds capable of forming
inactive complexes with the metal component. These materials
include certain acids such as phosphoric acid and organic
., .
acids such as citric and tartaric acids. Naturally, the post
; bleaching treatment of the hydrogenated organic liquid
requires additional filtration with the selected addition of
materials such as Filteraid to promote the substantial
complete removal of the residual amounts of metal hydro-
genation catalyst.
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Although hydrogenation of organic liquid improves
color relating to yellow and red components, it unfortunately
does not remove the pronounced green color from vegetable
oil, especially saybean oil. This green color in hydro-
genated vegetable oil is most unacceptable in products to be
; used for human consumption iOe., edible oils. At the present
time, color improvement in an organic liquid is obtained by -~
the use of selected additions of very finely dispersed solid -
adsorbent into a filtered hydrogenated organic liquid under
conditions whereby the color bodies are adsorbed by the solid
adsorbent. The o~ganic liquid containing the solid adsorbent
, .. .
; must again be filtered af-ter the addition of Filtexaid
; material, so that the solid adsorbent is removed. Naturally,
each filtering step involves the loss of product even with
careful operation under the state of present day mechanical
filtration technology.
Color improvement in organic liquid comes within
the definition of bleaching treatment. Many types of
,
materials are employed for this purpose. For example,
~0 bleaching earth, activated carbon, acld-activated earth and -
~pent hyarogenation catalyst can be employed~ However, the
problem in conducting the hLeaching treatment, as in refin-
~ ing, also involves mechanical filtration procedures to remove
; the dispersed solids from the puri~ied organic liquid. The
same filtration problems additionally exist in the deodor-
ization treatment where a solid dispersed material is
employed. Any introduction into the organic liquid of a
solid material in a finely dispersed state requires present1y
a subsequent mechanical filtration step which must be
~ 30 cond`uctedvery carefully so that the ultimate degree of removal
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~: i5 obtained without unduly high product losses.
The present invention is a process which employs a
combination of steps familiar in everyday practices in the
refining and decoloring of organic liquids. ~owever, there
. .
are added certain novel steps whereby the resultant com-
bination of steps produces the desired refining and decolor-
--i ing and/or deodorizing treatments without mechanical filtration
of the organic liquid. Furthermore, substantially complete
removal of even small amounts of finely divided solid materials
,1'.,'. ~ ~
is obtained by uncomplicated procedures and equipment. In
addition, the problems involved with oxidization of the
organic liquid during mechanical filtration are avoided to
..~
~ insure optimum color and odor characteristics in the organic
~ ~ .
liquid.
SUMMARY OF THE INVENTION
.,~" _ .
~ In one particular aspect the present inVentiQn
~ ,. . .
provides a process for the purification of a hydrogenated -
refined substance selected from the group consisting of fats,
animal oils and vegetable oils, said hydrogenated refined
. ~ .
~-~ 20 substance containing color bodies and carrying entxained
~; ,`.~ ,
hydrogenation catalyst, which comprises subjecting said
~ hydrogenated refined substance in admixture with a finely
; dispersed solid adsorbent adapted to remove color bodies,
in an atmosphere substantially devoid of oxygen-containing
gases, to electrofiltration for the substantially complete
.
removal of the hydrogenation catalyst and solid adsorbent
; from the hydrogenated product, thereby providing a solids-
free quality improved hydrogenated product.
.. . .
` In another particular aspect the present invention
provides a process for the hydrogenation and purification of
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- a substance selected from the group consisting of fats,
animal oils and vegetable oils comprising: (a) refining said
: substance to remove gross impurities; (b) forming a mixture
of the reined product of step (a), a finely divided hydro-
genation catalyst and a finely dispersed solid adsorbent
; adapted to remove color bodies in an atmosphere substantially
, devoid of oxygen-containing gases; (c) hydrogenating the
refined product of step (a) with hydrogen in the presence of
i said hydrogenation catalyst and=~said solid adsorbent, and
:;. 10 at elevated temperatures, thereby producing a hydrogenated :: :
`; :
product carrying the entrained hydrogenation catalyst and :
the solid adsorbent; and (d) in an atmosphere substantially
devoid of oxygen-containing gases, subjecting the product
. of step (c) to electrofiltration for the substantially
complete removal of the hydrogenation catalyst and solid
~ . . . .
adsorbent from said hydrogenated product, thexeby providing
a solids-free, color improved hydrogenated product.
In a further particular aspect the present
invention provides a process for the hydrogenation and
~ 20 purification of a substance selected from the group consîst-
: ing of fats, animal oils and vegetable oils comprising: :
(a) refining said substance to remove gross impurities;
(b) hydrogenating the refined product of step (a) with
hydrogen in the presence of a finely divided hydrogenation
ca~alyst dispersed therein and at elevated temperatures,
- thereby forming a hydrogenated product carrying entrained
hydrogenation catalyst; (c) forming a mixture of said ~`
hydrogenated product carrying entrained hyarogenation
catalyst and a finely dispersed solid adsorbent adapted to
remove color bodies in an atmosphere substantially devoid of
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; oxygen-containing gases; and (d) in an atmosphere sub-
stantially devoid of oxygen-containing gases sub~ecting
- the mixture obtained in step (c) to electrofiltration for
~ the substantially complete removal of the hydrogenation
: catalyst and solid adsorbent from the hydrogenated organic
liquid thereby providing a solids-free, color improved
hydrogena~ed product.
DESCRIPTIO~ OF THE DRAWING
...., . ... _ .
The drawing is a diagrammatic illustration, in flow
schematic, of an arrangement of apparatus for carrying out
the novel steps o~ the present process.
DESCRIPTION OF SPECIFIC EMBODIMENTS
The present p`rocess will be described in the
purification of one type of organic liquid, namely soybean
oil. However, it will be appreciated that this process is
equally applicable and of utility with other types of
organic liquid, e.g., fats, and animals and vegetable oils.
With reference to the drawing, there is shown an arrangement
of apparatus for practicing the steps involved in the
present process. However, other arrangements of appartus
which are capable of carrying out the listed steps, by
direct or equivalent means, can be employed with equal effect
for refining, decoloring and/or deodorizing treatments. More
particularly, the steps for refining are conducted in a
refining vessel or separator ll,a hydrogenation converter 12,
a mixer 13, and an electrofilter 14.
The sepa~ator 11 receives a charge of organic liquid
; such as raw soybean oil through an inlet 16 to which is
added a suitable aqueous reagent through a second inlet 17
immediately prior to its entry into the separator. For
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~765iZ~t
example, the aqueous reagent may be alkali or an acid.
Usually, the aqueous reagent is a relatively weak alkali
such as caustic of 5% by weight concentration. However,
in certain instances, mineral acids such as sulphuric acid
can be employed. The aqueous reagent converts certain
impurities in the raw soybean oil into a form where they
are separated from the refined soybean oil by settling or
other physical separations conducted in the separator 11
The aqueous phase car~ying the separated impurities
is removed in an underflow outlet 18 from the separator. The
aqueous phase is sent to a suitable disposal facility wherein
the removed impurities, such as alkali metal salts, are
recovered or suitably disposed. The refined soybean oil from
; the separator 11 passes through an outlet 19, a pump 21, check
valve 22 and inlet 23 into the converter 12. The check valve
22 insures that all subsequent processing is undertaken at
superatmospheric pressure conditions.
In addition to refined soybean oil, the converter
12 also receives through the inlet 23 a charge of hydro-
yenation catalyst introduced at metered amounts through a
valve 24. The hydrogenation catalyst can be of any suit-
able form such as a metal hydrogenation catalyst. For
example, the metal hydrogenation catalyst may be nickeI metal
carried upon a supporting substrate formed of kieselguhr.
Only small amounts of hydrogenation catalyst are employea;
however, the cataly5t is present in a very finely diviaed
state to improve the efficiency of hydrogenation of the
.. . ..
refined soybean oil. In addition, the converter 12 rece;ves
hydrogen gas at superatmospheric pressure through an inlet
26 which also includes a check valve 27 to insure
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hydrogenation reaction at superatmospheric pressure. The
converter 12 may include heating coils and mixers (not shown)
to facilitate reaching the desired hydrogenation level in
the soybean oil.
After the hydrogenation of the soybean oil is
completed, excess hydrogen gas is vented through an outlet
~8 and a control valve 29 until the superatmospheric pressure
in the conver~er drops to some suitable level, for example,
; 10 psi. The superatmospheric p~essure of the residual
hydrogen in the converter 12 is not critical, bu~ it should
be sufficient that all downstream processing steps are
~ conducted in a hydrogen atmosphere sufficient to completely
;~ exclude the entry of any oxygen-containing gases. If desired,
an inert gas other than hydrogen, can be employed in the
subsequent steps to exclude the entry of oxygen-containing
gases. In normal practices, the finely divided catalyst
I would be removed from the hydrogenated soybean oil by
mechanical filtration. However, the mechanical filtration
` is avoided by the following step of the present process.
The hydrogenated soybean oil and entrained ~inely
divided hydrogenation catalyst is removed from the converter
12 through the outlet 31 and a control valve 32 for intro-
duction intG the mixer 13. The mixer 13 can receive al~
or part of the admixture of soybean oil and hydrogenation
catalyst from the converter 12. Alternatively, a
regulated flow of the admixture can be sen~ through the
mixer 13. The mixer 13 also receives a proper charge of
- solid adsorbent (e.g., 0.1% wt.) introduced through an
inlet 33 and control valve 34. More particularly, in
either batch or continuous operations, a sufficient amount
bm.
: 1~76520
of the solid adsorbent is added to the hydrogenated soybean
oil that the color bodies are removed effectively by
adsorption.
Assume that the solid adsorbent is introduced at a ;~
proper rate by adjusting the valve 34 relative to the flow of
hydrogenated soybean oil carrying entrained finely divided
hydrogenation catalyst regulated by the valve 32. The mixer
13 is operated to provide a finely divided dispersion of
solid adsorbent at relative con~tant concentration with the
soybean oil and entrained catalyst. For this purpose, the
mixer 13 includes a shaft carrying a plurality of mixing
.
paddles 36 rotated by prime mover 37 comprising an electric
motor carrying an integral gear box. The resultant admixture
- is passed directly from the mixer 13 through an outlet 38
into the electrofilter 14.
The solid adsorbent can be selected from the group
, of materials employed in the conventional decoloring of
organic liquid. Examples of the solid adsorbents include
spent hydrogenation catalyst, bleaching earth, fuller's
earth, diatomaceous earth, activated carbon, and kieselguhr.
Of a special utility in removing from soybean oil the green
color resulting from chlorophyll is the acid activated earth
' materials. Certain of the solid adsorbents are obviously o -
greater utility than others depending upon the particular
type of organic liquid and its prior treatments encountered
in the edible oil industry. -~
The hydrogenation reaction in the converter 12
usually reduces the red and yellow color producing
constituents in soybean oil. As a result, the green color
from chlorQphyll becomes greatly pronounced. Thus, the
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3~137652(~
solid adsorbent is selected to remove chlorophyll which
has a color band in 6400 and 660Q angstroms. Other color
bodies require some variation in type and amounts of the
solid adsorbent fox the complete removal of these materials.
An effec.tive amount of the solid adsorbent should be used.
. Generally,-more than about 0.01% by weight of the solid
adsorbent must be introduced in admixture into the hydro-
genated soybean oil carrying the finely divided hydrogenation
~ catalyst. . --
- 10 In many cases, the admixture flows from the mixer
13 through to the.outlet 38 as a result of the residual .. .
:- superatmospheric hydrogen pressure. However, a pump 39 can,' '
be used to move the`admixture ~rom the mixer 13 through a
check valve 41 into the electrofilter 14 for process control
or for other reasons.
The electrofilter 14 receives the hydrogenated
j .
soybean oil, entrained catalyst and the solid adsorbent
under superatmospheric pressure and in an atmosphere
substantially devoid of oxygen-containing gases. Exclusion
, .
.~ 20 of oxygen-containing gases from the mixer 13 and the
ele!ctrofilter 14 produces a superior decoloring of the
organic liquid, and specifically in the present example, the
soybean oil. . -
.~ . The electrofilter 14 is a pressure vessel 15
containing a porous particulate bed disposed in an intense
electrical field so that solids in the organic liquid are
; removed by their induced adherence to the particulate bed.
The electrofilter 14 is formed of a metal vessel 15 with
an inlet 42 and outlet 56 and contains a suitable particulate
solid material 44 completely filling its interior. The
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electrofilter 14 receives pre~erably a continuous and
unlform flow of the admixture flowing through an inlet 42 ~ ~ -
into a distributor 43 provided by pipe cross arms containing
metering openings. The interior of the vessel contains a
plurality of energized electrodes 46 in spaced relationship
to a plurality of grounded electrodes 47. Pre~erably, the
electrodes 46 and 47 are vertically elongated metal tubes and
have substantial overlapping dimensions defining an electric
field within the particulate ma`terial 44 contained in the
electrofilter 14. The electrodes 46 are suspended from the - ~ -
vessel 15 by insulators 48. In addition, the electrodes 46
are energized by an external power supply 49 providing a
high intensity potential through a conductor 51, an entrance
bushing 52 and a flexible lead 53 to the electrodes 46. The
power supply 49 can be grounded to the vessel 15 by conductor
54.
The electrofilter 14 applies the high intensity -
electric field to induce the tenaceous adhesion of the
hydrogenation catalyst and solid adsorbent upon the particu-
: . .
late material 44. It is preferred that the power supply 49
provides a high intensity d.c. electric field within the
particulate material 44 contained within the electric field
. . .
de~ined by the electrodes 46 and 47. Preferably, the
electric field produces a potential gradient in the particu-
,! late material 44 of about not less than 20 kilovolts per
inch. A certain type o~ particulate material 44 should be
employed for optimum results. The material 44 are rigid
solid particles having a relatively low dielectric constant
(below about 6). More particularly, the particulate material
should be chemically inert, incompressible, hard ~ranular and
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rigid in nature with a non-spheroidal configuration. The
particulate material can be a solid mineral containing
crystalline silicon dioxide such as flint, garnet, granite
and fused quartz. Preferably, the mineral is crushed to
provide non-spheroidal configurations which have relatively
discontinuous surfaces. For example, crushed flint rock
having particle siæes of its minimum dimensions between 1/8
and 1/2 inch are employed to good advantage in the present
process. ~-
The electrofilter 14 produces the substantially
complete removal of the hydrogenation catalyst and the solid
adsorbent as the organic liquid passes from the inlet 42
throu~h the bed material 44 to the outlet 56. As a result,
the soybean oil removed through the outlet 56 is simultanously
; solids-free and color improved. A second mechanical filtration
,.,;! step of conventional refining is avoided. The product soybean
oil flows thxough a backpressure valve 57 which is set to
maintain the desired superatmospheric pressure previously
mentioned in the converter, mixer and electrofilter. The
; 20 product soybean oil is carried through a conduit 58 to a
,~ subsequent utilization, as for example, consumer product.
In a pilot plant test, a small amount (about 0.1%
by weight) of a commercial bleaching clay (Filtrol~ rade 105)
; was added to hydrogenated soybean oil in a mixer, thereby
forming a mixture of hydrogenated soybean oil, nickel hydro-
genation catalyst and the bleaching clay. This mixture was
passed through a small electrofilter having crushed flint
rock (Flintbrasive~ o. 11) in an electrical field having a
gradient of about 20 kv/in,, d.c. Complete removal of all
entrained solids was obtained with the quality improved
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hydrogenated soybean oil having a "green density"
(spectrophotometer) color of 83. Electrofiltration of the
hydrogenated soybean oil (without bleaching clay) produced
a color of 160. The commercial acceptable standard color i5
100, so that the present process produces a color improvement
vastly superior to conventional practices.
In another embodiment of this process, the solid
adsorbent can be added directly to the refined organic liquid
introduced through the inlet 23cinto the converter 12 prior
to, during, or after the hydrogenation reaction. For this
, .; .. .
purpose, a sourc~ of the solid aasorbent is passed through a
-~ pump 61 and checkvalve 62 into the inlet 23 of the converter
12. The solid adsorbent can be carried in a small amount of
hydrogenated organic liquid to improve pumpability, if
desired. The hydrogenation reaction in the converter 12
insures complete admixture. Introduction of the solid
adsorbent directly into the converter 12 makes optional the
;~ use of the mixer 13. However, the results produced by
~il either embodiment of the present process are the same.
It will be apparent from the foregoing steps ~hat
at least two expensive and difficult-to-conduct mechanical
filtration steps have been avoided. The first mechanical
step which is avoided is that conventionally following the
converter 12. The second mechanical filtration step which
is avoided is that conventionally following the introduction
of solid adsorbent in the mixer 13. In addition to these
advantages, the produc-t soybean oil from the electrofilter
- 14 is exceptional in color and very clean in that, for
: practical purposes, no residual solids (including nickel~ o~
hydrogenation catalyst and solid adsorbent are present in any
'
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~765z~
significant amounts. No subsequent conventional treatment
for removing nickel metal contaminants, such as by treatment
with phosphoric acid or orqanic acids such as citric or
tartaric is required! In many cases, the solid adsorbent
introduced into the mixer 13 can also provide substantial
deodorization of the hydrogenated soybean oil as an added
advantage.
In addition to the above listed advantages, it
will be apparent that there has~been provided a process
well adapted for improving the color, odor and reducing
solids of organio liquids. The present process is completely
,:
;~ compatible with present day operations in the food indust~y,
or other places, where organic liquids are puri~ied. It is
to be understood that certain eatures and alterations of
. .,
the present process may be employed without departing from
the spirit of this invention. This is contemplated by, and
is within, the scope of the appended claims. It i5 intended
that the presently described embodiments are to be taken as
illustrative of the claimed proces~.
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