US2206210A - Process of removing materials containing phosphatides from vegetable oils - Google Patents

Description

July 2,1940. B. H. THURMAN 2,206,210 PRCESS OF REHOVING MATERIALS CONTAINING PHOSPHATIDES FRU VEGETABLE OILS4 Filed Dec. ga. 19B? gmfmfafm Planetas 2.11940 i 2,206,210

UNrrsDsTATEs PATENT OFFICE :spazio PROCESS F BEMOVING (10N- TAINING PHOSPHATIDES FROM VEGE- TABLE GILS Benjamin H. Thurman, Bronxville, N. Y., assignor to Defining, Ine., Benn, Nev., a corporation of Nevada Y Application December 9, 1937, Scl'lll No. 179,014 Bclllmi; (Cl. ZBO- 428) This invention relates to a process of removing limiting theduration of the time the oils remain materials containing phosphatides from vegein a heated condition to such a brief time as to table oils and more particularly to a process of prevent injury to the oils or to the phosphatides continuously removing such materials from vegey contained therein.

table oils to improve the quality of the oils and It is still further an object of the invention 5 recover valuable products therefrom. to maintain the oils in such a heated condition Vegetable oils, for example. cottonseed, soya at the time of subjecting the same to centrifugal bean. linseed, etc., as they come from thepressseparation as to cause the precipitated materials `or expeller contain various impurities commonly to coalesce or agglomerate whereby to condition m l0 referred to as foots These foots are gummy the same for separation from the pm'iiied oil,

viscous materials containing large amounts of irrespective oi' whether the heat is applied bephosphatides. Upon standing, a portion of the fore or during centrifugation. foots settles slowly in the cold to form a sludge vDesirably, the process contemplates separation which must be removed if a clear oil is to be of the foots from the vegetable oils promptly l5 '5 produced. `It has been common practice to after they are expressed and before the same maintain the oil in storage for weeks or even have a deteriorating effect upon the oil or upon months `to allow the foots to settle and then dethe phosphatides contained therein although it is cant the supernatant oil from the sludge. A recognized that the invention has utility with clean separation cannot be effected in this manrespect to the treatment of oils which have been ner and large amounts of `valuable oil are remaintained in storage for a considerable period 20 tained inthe sludge. Filtering of the oil to reof time. move thev foots has also been suggested but the Asindicated above, the separated foots or gums gummy and viscous nature thereof makes this contain valuable constituents, such as phos- Voperation slow and dimcult. phatides. The gums from edible oils, such as Contrary to the view entertained by the experts cottonseed or`soya bean, may be further treated 2li` of the art I have heretofore discovered that phosto separate out `and purify the phosphatides as phatides, in utilizable form, were contained in disclosed in applicants copending application the gums of expressed vegetable oils obtained, above referred to. The puriiled phosphatides for example, from cottonseed, soy bean, linseed, form valuable stabilizing materials for edible B0 rape seed, etc. An application based upon this products. while the gums separated from drying 30 discoveryhas been illed by me Serial No. 6,446, oils, such as linseed, form valuable materials for iiled February 14, 1935, which application is a making putty and other analogous substances continuation in part of Serial No. 644,137, iiled because of their anti-oxidant properies. Also November 23, 1932, and Serial No. 676.932, filed the removalof the gums from any of the vege- 55 June 21, 1933. In those applications a preclpitable oils improve their color and facilitate 85 tating reagent is employed and phosphatides are their further refining. 'I'he acid sludge from acid recovered without the theretofore existing pracreiining is reduced in amount and also valuable tice of using a solvent for extracting the phosphosphatides are removed before being degraded -phatides from the beans. by the acid. The soap stock separated from al- 'Ihe present invention constitutes a variation kali treated oil, which has previously been cen- 4o p `from the application aforesaid in that no pretrifuged to remove the gums or foots, is also of cipitating media is employed whilethe tendency higher quality as it is not contaminated with of the separated foots tostck to the bowl of a large amounts of gums, less refining reagent centrifugal separator is overcome in the manner is necessary and the rening loss ls reduced. 15 hereinafter explained. Drying oils, such as linseed treated in accordance d5 It is therefore one of the objects of the present with the present process, become non-break invention to provide a process by which such oils" if all traces of moisture are removed theregums or foots can be continuously centrifugally from. That is to say the oils will not precipitate separated from the oil without the employment of further foots or gums when heated to a temperaa. precipitating reagent and without injury to ture of 500 F. or higher. 60 the oil or to the phosphatides contained in said It is, therefore, an object of the invention to gums. provide a process by which vegetable oils may It is another objectl of the invention to pro-` be conditioned for alkali reiining operations to -vide suillcient heat to cause the precipitation oi" reduce the reiining loss therein andV provide a `the naturally occurring gums inthe oil while higher quality soap stock.

' A'i'urther object of the invention-is to provide aprocess of making non-break drying'oils.

Other objects and advantages of the invention will appear in the following detailed description of preferred embodiments of my'invention, def scribed in connection with the attached drawing, of which:

Figure 1 is a schematic drawing of an apparatus suitable for carrying out the present invention, and

Figure 2 is a diagrammatic drawing of a centrifugal separator particularly adapted for carrying out the present process.

The centrifugal separator 9 illustrated diagrammatically in Figure 2 includes a centrifugal bowl I capable of being rotated at high speed by any suitable drive means, for example, a pulley II. A stationary inlet member I3 carried by a cover Il may be employed to introduce materials to be separated into an inner member I5, which delivers the materials to the lower interior portion of the centrifugal bowl. The heavier etlluent moves upwardly adjacent the walls ofthe bowl I0 and is discharged through a port I6 into a pan II which delivers the heavier effluent from the centrifuge. The lighter effluent passes upwardly adjacent the inner member l 5 and is discharged through a port I8 into the cover I4 and thus from the centrifugal through a pipe I9. The centrifugal machine is preferably provided with a heating jacket 20 completely surrounding the bowl l0 and provided with an inlet 2| and an outlet 22 for any desired gaseous heating medium, for example, steam. The oil containing foots may be delivered to the centrifugal through a pipe 23 which is connected to the stationary inlet member I3.

One of the salient features of the present invention is the introduction of water or other liquid material, such as a salt solution which is of greater specific gravity than the oil, immediately into the entrance of the centrifugal separator along with the oil to be centrifuged to carry the foots out of the centrifuge. The gums or foots constitute the heavier effluent and are thrown against the walls of thebowl I0 by centrifugal force. These materials are extremely viscous and sticky and will not by themselves flow upwardly along the walls of the bowl and discharge through the port I6. I have found that water or aqueous salt solution will cause the foots to be contlnuously discharged from Athe centrifuge. .No

, oil.

The application of heat to the outer surface of the bowl also reduces the viscosity and vhelps to prevent `sticking of the gums or foots to the bowl walls. With certain types of oil the application of heat may be sufiicient yto cause the foots to flow or slide out of the centrifugal bowl in which case the introduction of other liquid through the pipe `2li may be unnecessary. With other oils better results may be obtained 'by employing the carrying liquid alone without the application of heat. In most instances the employment of both produces best results but it will be understood that certain oils may be best separated with the application of heat only while with certain other oils the introduction of the carrier liquid ,alone produces best results,

The temperature at which the oil is introduced into the centrifugal separator will depend upon the nature of the oil being treated and no exact temperature or4 temperature range suitable for thev point or origin of the oil as well as the process used in extracting the oil. In general more gums are removed at the lowest temperature at which the oil is sumciently liquid to provide eilicient separation. i With soya bean oil, for example, better results are usually obtained when the oil entering the centrifuge is at a relatively high temperature, for example, 140 to 160 F., while with other oils separation is more complete at a lower temperature, for example, 70 to 100 F. With some oils which remain liquid below '70 F. temperatures lower than 70 F. may be employed and still others may require temperatures between 1009 and 140 F. Separation at temperaf tures materially above 160 F. is usually impractical as water vapors tend to form in the layer of foots in the centrifugal rendering portlonsof the foots lighter than the oil, thus causing priming or delivery of the foots with the oil.

Vegetable oils ordinarily come from the press or expeller at temperatures from approximately 140 to 160 F., and thus in many instances these heated oils may be delivered directly to the centrifuge. In other cases it may be desirable to reduce thertemperature of the oils before centrifuging. This may be done either by allowing the oils to stand in storage `or passing the same through a continuous cooling device. Also, oils which have been allowed to cool in storage may have their temperature raised by heating the same until the proper temperature for the particular oil is obtained before they are delivered to the centrifuge. l

In Figure 1 a tank 25 indicates a source of supply for vegetable oils and may be either a large storage tank or a small tank for temporarily receiving the oils from the presses. If the oil is at the correct temperature for separation -of the particular oil being treated, it may be delivered directly to the centrifuge 9 by pipes 26 and 23 by opening the valve 28 in the pipe 26 and closing the valve 29 in the pipe 30. If it is desirable or necessary to raise or lower the temperature of the cil it may be pumped through the heat exchanger 3| by a pump 32. The heat exchanger 3| may include a coil 33 enclosed in a casing 34 through which a heating or cooling medium, such as. for example, water, may be circulated. The oil is then delivered to the centrifuge through the pipe 23. A small amount of water or other carrying liquid is withdrawn from a tank 35 and delivered by a pipe 24 into the stream ofoil entering the centrifuge 9. The proportions of carrying fiuid and oil are not in general extremely critical so that accurately proportioning devices are not usually necessary, but such proportioning devices are well known in the art and can be employed if desired. Foots are discharged from the centrifuge from the pan I'I and delivered to a receiver 36 while the oil is discharged through the pipe I9 into a receiver 38. The oil from which the foots have been removed may be then carried to subsequent reilning steps vor may be sold as an article of commerce.

In the case of drying oils particularly, it is introduced therein by admixture of-small portions of the carrying fluid fromthe tank 35. 'Ihis may be conveniently accomplished by vacuum drying the oil in a vacuum chamber 39 provided for with a condenser 40 for condensing water vapors withdrawn from the oil and a receiver 4| for receiving the condensed water. A vacuum may be maintained in the vacuum chamber 39 by means of a vacuum pump 42 connected to the receiver 4I. In many cases the amount of water vapor withdrawn from the oil is sumciently small that the condenser 40 and receiver 4I may be eliminated and the vapor pump 42 connected directly to the vacuum chamber 39.

If the oil being dried is centrifuged at a relatively high temperature, for example, 140 to 160 F., the oil may be delivered directly to the vacuum chamber through the pipes 43 and 44 but if low temperatures are found desirable in the centrifuge 9 for a particular oil, the centrifuged oil may be pumped by a pump 45 through a heat exchanger 46 which may be entirely similar to the heat exchanger 3|. Ihe oil is heated in the heat exchanger to the temperature necessary to substantially completely eliminate all moisture in the evaporating chamber 39. Thus, for ex ample, the oil may be heated to temperatures from 140 to 212 F. or even higher if necessary.

'I'he dried oil may be withdrawn from the evaporating chamber 39 through a pump 41 and delivered through a pipe 48 to a receiver 49. An extremely stable oil is thereby produced which in the case of drying oils is classed as a nonbreak oil, i. e., no further precipitation of gums or foots will take place even if the oil is treated toas high as 500 F. Edible oils may also be passed through the vacuum chamber 39 if desired. 'I'he drying of the oils renders them ex tremely stable against the formation of additional free fatty acids and the oils may be maintained in storage for extended lengths of time prior to refining without degrading.

Even if the oil is delivered to the centrifuge at temperatures as high as 160 F. the application of further heat by passing a heating medium through the heating jacket 20 surrounding the centrifugal bowl produces advantageous results. When the bowl is not thus heated, the rapid rotation of the bowl in contact with air within the heating jacket 20 violently agitates the air and causes heat to be rapidly transferred from the bowl wall to the wall of the heating jacket 20 and thus to the atmosphere. This effect is even more pronounced if no jacket is provided around the centrifugal bowl as heat from the bowl is rapidly dissipated into the atmosphere. This lowers the temperature of the bowl Walls and in many cases causes the foots or gums to tenaciously adhere thereto. 'Ihe temperature of the foots may, by the present invention', be maintained when the oil is delivered in a heated condition to the centrifuge and when relatively cool oil is delivered to the centrifuge the temperature of the foots may be raised immediately adjacentth`e centrifugal bowl walls so that the foots will slide or flow out of the centrifuge. As before indicated, it is impractical to heat the oil entering the centrifuge to a temperature sufficient to cause this sliding the carrier liquid described or the to be maintained at the highest temperature practical without priming and also allows the foots to be heated before discharge even though separation in the centrifugal bowl is more efficient at lower temperatures than the discharge temperature of the foots.

As hereinbefore indicated, the introduction of a carrying iluid suchas water or a salt solution into the centrifugal bowl materially assists in carrying the foots out of the bowl and with certain types of oil may be employed without the ap plication of heat to the centrifugal bowl. Very small amounts of carrying liquid are ordinarily sufficient, for example, one-fourth to 1% of the weight of the oil, although larger proportions of water up to, for example, 10% are sometimes advantageous. The carrying liquid should be of greater specific gravity than the oil and substantially immiscible with the oil, and is desirable of even greater specific gravity than the foots so as to mix with and iloat the foots out of the centrifuge. Wateris ordinarily employed for this purpose although salt solutions, such as solutions of sodium chloride, are many times advantageous because of their tendency to prevent the formation of emulsions between the oil, water and foots. Any Water soluble salt which is substantially inert to the oil can thus be employed. The carrying liquid does not function as a reagent for precipitating and rendering gums insoluble and it is, therefore, desired to avoid as far as possible mixing of the carrying solution with the oil. Such mixing is not necessary and may in some instances form undesirable emulsions with thr.I oil.

The temperature of the carrier fluid is preferably that of the oil entering the centrifuge but may be of a higher temperature in order to raise or maintain the temperature of the foots so as to reduce their viscosity and assist in carrying them out of the centrifuge. Thus carrier fluids at a temperature of 100 to 180 F. can be successfully employed.

In the processof the present invention the foots or gums which usually settle as a sludge in vegetable oils are quickly separated from the oil in a continuous manner. No precipitating agent need be employed and thoroughly mixed with the oil to precipitate the gums. However, I have discovered that there is a certain amount of moisture contained in the oils as a result of the usual hot pressing operation which inherently functions, to some extent, as a precipitating reagent. The separated n' iterials discharge continuously from the centrifugal when application of heat to the bowl of the centrifugal or both are employed depending upon the nature of the oil being treated.

While I have disclosed the preferred embodiments of my invention it is understood that the details thereof may be varied within the scope of the following claims.

What I claim is:

1. A continuous process of separating gums containing phosphatides from fatty oils which comprises the steps of quickly precipitating said gums with the aid of a precipitating agent comprising moisture in such a small quantity as to produce gums incapable of said continuous centrifugal separation, promptly and continuously, before injury to said oil by said precipitated gums, centrifugally separating the precipitated gums from the oil, facilitating such centrifugal separation of the previously precipitated gums by introducing a carrier liquid heavier than said 76 oils into the centrifugal separator whereby to condition the previously precipitated gums for discharge from the bowl without adherence thereto.

2. The process as defined in claim 1 in which the carrier liquid is no greater than 10% by weight of the oil.

3. The process as defined in claim 1 in which the carrier liquid is inert to said oil whereby to prevent injury thereto.

4. The process as defined in claim 1in which the carrier liquid is of greater specific gravity than the foots. Y

5. The process as defined in claim 1 in which the carrier liquid comprises a salt solution.

6. A continuous process for separating gums containing phosphatidic material from fatty oils which comprises the steps of: continuously sub- :lectin: said oils, in the presence of a precipitating reagent of a character and amount insufficient to substantially attack the oil or the free fatty acids contained therein and insumcient to form foots capable of said centrifugal separation, to a temperature sumcient to rapidly precipitate the gums in the form of sticky and diicultly separable foots, promptly. before injury to the oil by said foots. centrifugally separating said foots from the oil, facilitating such separation of the previously precipitated gums by applying heat to the zone of centrifugal separation whereby to cause said sticky foots to be discharged from the centrifugal without adherence thereto and further facilitating said separation by simultaneously introducing a. heavier carrier liquid during the centrifugal separation.

BENJAMIN H. 'I'HURMAN.

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