US2205971A - Process of refining animal and vegetable oils - Google Patents

Description

0- I B. CLAYTON ET AL 2,205, 71 PROCESS OF REFINING ANIMAL AND VEGETABLE OILS v I Filed Nov. 15, 1937 Firm/1V6 Pings/yr g ue/rm flz/mw/lv Curran 4, Bar/4mm! 7/1 0014 v fected.

' a process of refining Patented June 25, 1940 mmmd vaoaraam ritocass on OFFICE Clayton, Houston, .lex.I and urman, B

Nev

nxville, N. I, "signers to I Refining, Ina, Reno, New, a corporation of Application November 15. 1931, Serial No. 114.120 12 claim. (01. 260425) j inns invention relates to a proce animal and vegetable oils and more to a process employing an agent refining losses are In the refining of vegetable-and animal oils, a refining reagent, which is ordinarily an aqueous solution, is mixed with an-oil containing impurities so as to react with the impurities to render the same separable from the oil by difference in specific gravity. An emulsion, which is apparently of the water and oil type, tends to form during such mixing and it is necessary to break. or prevent the formation of such an emulsion before adequate separation can be efample, and 160 F. and usually between and F. have been employed to break the emulsion so that the foots produced by treating the oil with the refining reagent will settle from the oil or can be centrifugally separated therefrom. The refining reagents employed will, in general, also attack the oil as well as impurities contained therein, and this attack upon the oil is increased by the elevated temperatures so that refining losses are increased or the quality of the oil decreased.

In accordance with the present invention, an agent is employed which will either oppose the formation of or break the usual emulsion without the necessity of ever having the mixture at the emulsion breaking or opposing temperatures above mentioned. Only suflicient heat is necessary to cause the oil to be in a fiowable condition and unnecessary refining losses or injury to the oil are largely prevented.

It is, therefore, a'n'object of the invention to provide a process of refining animal and vegetable oils in which an emulsion opposing or breaking agent is employed. Another object of the invention is to provide a process of refining animal and vegetable oils in which separation of foots from the oilsis-* effected at relatively low temperatures. 7 Y A further object of the invention is to provide in which an emulsion opposing or breaking agent oil with a refining reagent.

While an emulsion, such as above,

es of refining which opposes or breaks the emulsion which tends agent.

clude a proportioning pump it for withdrawing animal and vegetable oils tends to form in almost any type of refining, including so-called partial refining or degumalthough it is advantageous in other types of refining of such oils.-

It is, therefore, a still further object of the invention to provide a process of refining animal with an alkaline reagent in which an emulsion opposing or breaking agent is employed to avoid the necessity of operations at elevated temperatures.

Other advantages and embodiments of the invention will appear in the following description of the invention given with reference to the attached drawing which is a diagrammatic drawing of one form of apparatus suitable for carrying out the present invention.

Referring to the drawing, the apparatus shown is designed for can v and includes a source of supply for the oil, shown of supply. for the emulsion breaking agent, shown as a tank I l, a source of supply for the refining reagent shown as a tank II, a proportioning mechanism indicated generally at It, a treating coil l4, and a centrifugal ll.

'the tank It and delivering th'esame to a mixer I1 for mixing the oil with the emulsion breaking The proportioning device may also inan emulsion breaking agent from the tank If and 'deliveringthe same to the mixer II. The

proportioning device may also include a proper tioning pump 20 for withdrawing refining reagent from the tank, I 2 and delivering the same with. the oil. The proportionlng pumps l0,

g out a continuous processi'or mixing the refining reagenttrio motor 22 and may have variable speed de- I breaking agent,

A pump 20 and vices 23 and 24 positioned between the various pumps so that the proportions of the oil, emulsion breaking agent and refining reagent can be varied by changing the variable speed devices 23 and 24 and the total amount of the various materials-varied by changing the speed of the motor 22. The particular proportioning device described is merely one way of securing accu-'- rately proportioned streams of materials and any other type of proportioning mechanism which will deliver such accurately proportioned streams can be substituted therefor.

The mixer l'I may be any suitable type of flowor continuous mixer, for example, a device in which a stream of one material is injected at right angles into the stream of the other material or it may be a mechanical agitator into which the streams of oil and emulsion breaking agent are delivered and the resulting mixture continuously withdrawn. It is preferred to have the oil and emulsion breaking agent thoroughly mixed before admixture with the refining reagent but substantially equivalent results can be accomplished by mixing the emulsion breaking agent with the refining reagent prior to mixing with the oil. This can be accomplished by placing the mixer II in the pipe 25 between proportioning the mixer 21 and delivering the stream of emulsion breaking agent to the said mixer. The process can also be simplified by mixing proper proportions of the emulsion breaking agent with the refining reagent in the tank I2 so as to eliminate the tank ll, along with proportioning pump l8 and mixer 11. In general, the emulsion breaking agent is more miscible with the refining reagent than with the oil and therefore difficult to mix with the oil, but if an emulsion breaking agent which is miscible with the oil is employed, it can be mixed with the oil in the tank l0 instead of with the refining reagent in the tank l2. If desired, the stream of emulsion breaking agent can be delivered directly to the mixer 2| so that streams of oil, emulsion breaking agent, and refining reagent, are mixed in a single mixer. It is preferred to have the emulsion breaking agent present during the mixing of the oil and refining reagent so as to oppose the formation of an emulsion, but advantageous results can be secured by mixing the emulsion breaking agent with the mixture resulting from contacting the oil and refining reagent. Thus, a stream of emulsion breaking agent can be introduced into the mixoil and refiningreagent have been contacted. In any case, a

such an emulsion is immediately broken after its formation.

Mixing of the oil and refining reagent results in a mixture of oil and foots which, in the case of alkali refining, is predominantly soap stock. Due to the presence of the emulsion breaking agent, the mixture of oil, foots and emulsion is in condition for immediate centrifugal separation but in many types of 'refining, particularly alkali refining, it is desirable to provide additional time of contact between the oil and refining reagent in order to reduce the color of the oil. During this additional time,

the refining reagentcan act upon color impurities and adsorption of the reacted color impurities by foots effected. A convenient device for this purpose is a pipe coil such as the coil l4.

difliculty separable emulsion is prevented from forming or The mixture should be kept in sumcient state of movement to prevent stratification of the foots so that a substantially uniform mixture of oil and foots is maintained. This is particularly important when centrifugal separation is employed as stratification with the resultant delivery of large masses of foots to the centrifugal will result in imperfect separation by causing foots to be discharged with the oil. The movement of the oil or mild agitation thereof enables the particles of foots to repeatedly contact reacted color impurities in the oil such that they are adsorbed by, or otherwise combined with the foots. As stated above, the coil is an effective mechanism for this purpose but any other type of treating device, such as a mechanical agitator, which will provide proper movement of the mixture without breaking up of the particles of foots can be employed instead of the coil. If color removal is unnecessary or not desired, the mixture of oil and foots may be delivered directly to a suitable separating device such as a centrifugal separator l5.

The centrifugal separator 15 may be any suitable type of continuous centrifugal separator employing a rotating bowl from which the foots are separated from the oil by differences in specific gravity and the employment of centrifugal force. The oil constitutes the lighter effluent and may be discharged from the centrifugal through a spout 26 into an oil receiver 21. The type of emulsion breaking agents contemplated by the present invention substantially all separate with the foots as the heavier eflluent which is discharged through a spout 28 into a foots receiver 29. While any suitable type of centrifugal can be employed, the heated centrifuge disclosed in the copending application of Benjamin Clayton, Serial No. 34,258, filed August 1, 1935, is preferred as a more uniform delivery of the heavier eflluent can in most cases be secured by preventing the building up of layers of adherent material upon the walls of the centrifugal bowl.

It is unnecessary to use elevated temperatures in the present process but the 011 must be of sufiicient fluidity to provide for adequate mixing and for passage through the process. For this purpose the oil tank l0 may be provided with a heating coil 30 through which any desired heating medium, such as hot water or steam, can be passed in order to bring the oil to the required temperature. This temperature will vary with the type of oil being treated but will usua ly fall between temperatures of to 95 F. To prevent chilling of the oil due to admixture therewith of cold refining reagent or emulsion breaking agent, similar heating coils 3| and 32 may also be positioned in the tanks I I and I2, respectively. In order to simplify the apparatus it is sometimes possible to heat only the oil to a somewhat higher temperature than those indicated such that mixing relatively cool refining reagent or emulsion breaking agent therewith will not cool the oil below its fiow temperature. This enables the heating coils 3| and 32 to be eliminated. In some cases it is found that mixing may be at a relatively low temperature but that better color reduction or separation is accomplished at a somewhat higher temperature. In such cases the mixture may be heated in the treating device H as by surrounding the coil thereof with a heating jacket 33 through which any desired heating medium may be passed. The application of heat to the coil I4 is usually unnecessary and the temperature necessary to be case the oil may be usual refining formation is accomplished primarily by the emulsion breaking agent.. with certain oils it is' ei'or. reaction sometimes desirable to H or other treating device by passing a cooling medium through the Separation can ordinarily be accomplished I at temperatures ranging between substantially F. and F.

agents, in accordance with the present invennarily a relatively concentrated sulfuric acid altion, are concentrated solutions of salts which ugh o her acids, such as hydrochloric acid havesubstantially no reaction with the oil being can employ d- A usual acid re ng rea n refined Such salts should have high solubility is 6 Baum sulfuric acid in amounts between in water and examples are sodium chloride or and 3% depending upon the amount of im- ;.cultly separable emulsions are frequently encountered which can be broken or prevented from forming by the emulsion breaking agents of the present invention.

employed and the em 181011 breaking agent is Very dilute solutions of salts, acids and alkalies; depended upon been found suitable. The salt solutions are either which tends to f m when water is mixed with present during mixing or added immediately oil. By adding a concentrated salt solution or thereafter. the alcohols or esters of the present invention It has also been found ponification inhibiting and anti-sticking funcm y 6 carried 1 n h pp ra us disclosed tions even when elevated temperatures are emand the degummed oil delivered to a duplicate ployed for breaking the emulsion but, in general, apparatus for performing either an acid or alkali of refining, but in general from 3% of alcohol or ester or relatively concentrated solutions thereof are eflective. v

With any type of emulsion breaking agent, the proportions employed depend upon the amount of impurities in the oil and the type of refining refining or 'de umming; In alkali refining the reagents known to the art and in it the'proportions conventionally used can be em ,color removal,

destruction of refined oil is, therefore, largely prevented.

It will be noted that the particular apparatus disclosed provides a closed system from the entrance of the various materials into the process to the separation step such that air is excluded during the process. A closed mixing zone is preferred, particularly if considerable agitation is employed during mixing, as air may be beaten into the mixture to cause a more diificultly separable emulsion so as to require the employment of excessive amounts of emulsion breaking or opposing agent. In the present process the mixture is immediately conditioned for separation such that the entire process may be performed in a few minutes for example, mixing may take from less than 1 minute up to minutes, and separation not more than 3 take not more than from 4 to 8 If a longer treating time is required for such additional time will usually range from 2 to 5 minutes and will rarely exceed 10 minutes such that the entire process will rarely exceed to 18 minutes, and will usually require not more than 5 to 10 minutes. Since refining losses or other attacks on the oil by the refining reagent increase with time as well as temperature it is desirable to perform the process in as short time and at as low temperature as the nature of the oil and refining process permits. By employing emulsion opposing or breaking agents as herein disclosed, a quick process at low temperatures can be employed to minimize refining losses and reactions with the purified oil.

Salt solutions separated with the foots can ordinarily be separated therefrom by decantation or centrifugal separation, and many times can be reused in the process with or without purification. Alcohol or esters thereof separated with thefoots can be recovered for reuse by vaporization and condensation and the same is true of any of such materials which are present in the purified oil separated from the foots.

The term vegetable and animal oils as employed herein is intended to embrace and include oils and fats of the same general type as those specifically mentioned herein including fish oils.

While the preferred embod'ments of the invention have been disclosed, it is understood that the invention is not limited to the details thereof but may be varied within the scope of the following plaims.

We claim:

1. The process of refining vegetable and animal oils, which comprises, mixing said oils with a refining reagent at a relatively low temperature which is sufiiciently high that the oil is fiowable but which is below an emulsion breaking temperature, performing said mixing in the presence of an emulsion opposing or breaking agent so as to immediately produce a mixture of oiland foots conditioned for separation and thereafter centrifugally separating said foots from said oil.

2. The process of refining vegetable and animal oils, which comprises, mixing said oil with a refining reagent capable of reacting with impurities in said oil to form foots at a temperature sufiiciently high that the oil is fiowable but insufficient to break the emulsion which tends to form, breaking any emulsion which may tend to form during said mixing by incorporating with said mixture an emulsion opposing or breaking agent so as to condition the mixture for separaminutes.

minutes so that the ention; thereafter centrifugally' separating said foots from said oil.

. 3. The process of refining animal and vegetable oils, which comprises, mixing measured quantities of oil, refining reagent and emulsion breaking or opposing agent at a temperature sufflciently high that the oil is fiowable but sufficiently low that emulsion would be formed in the absence ofsaid agent, employing surficient amounts of said agent to oppose or break said emulsion so as to produce a mixture containing oil and foots in condition for centrifugal separation, thereafter centrifugally separating said foots from said oil.

4. The process of refining vegetable and animal oils, which comprises, mixing a measured quantity of said oil with a measured quantity of a refining reagent at a temperature at which the oil is fiowable but below an emulsion breaking temperature, performing said mixing in the presence of an emulsion opposing or breaking agent so as to form a mixture containing oil and foots in condition for centrifugal separation, maintaining said mixture for a time sufficient to provide for reaction of said reagent upon color impurities and promptly thereafter centrifugally separating said foots from said oil.

refining animal and vegetable oils, which comprises, mixing a measured quantity of said oil with a measured quantity of a refining reagent at a temperature sufliciently high to cause said oil to be in a fiowable condition but below the temperature at which the emulsion which tends to form during said mixing would be broken, incorporating an emulsion breaking or opposing agent in said mixture so as to condition said mixture for prompt centrifugal separation and promptly centrifugally separating the foots formed during said mixing from said oil.

6. The process of refining animal and vegetable oils, which comprises, mixing measured quantities of said oil with measured quantities of a refining reagent at a temperature at which the oil is fiowable but below an emulsion breaking temperature, incorporating in said mixture a suflicient quantity of an emulsion breaking or opposing agent to condition the resulting mixture for centrifugal separation and promptly thereafter centrifugally separating said oil from the resulting'sludge.

'7. The process of refining animal and vegetable oils, which comprises, mixing measured quantities of oil with measured quantities of alkaline at which the oil isfiowable but below an emulsion breaking temperature to form a mixture containing oil and soap stock, incorporating with said mixture sufiicient emulsion opposing or breaking agent to condition said mixture for centrifugal separation, and, promptly thereafter centrlfugally separating said soap stock along with said agent from said oil.

8. The process of refining animal and vegetable oils containing free fatty acids and color impurities, which comprises, mixing measured quantities of oil and alkaline refining reagent at a temperature at which the oil is fiowable but below an emulsion breaking temperature to form a mixture containing oil and soap stock, incorporating sufficient emulsion opposing or breaking, agent in said mixture to condition the resulting mixture for immediate centrifugal separation, passing said mixture to a centrifugal separator while providing sufficient time for excess refining reagent to act on said color impurities, maintaining said mixture during said pasof movement to prevent with said agent 9. A quick continuous process 01' refining animal and vegetable oils, which comprises, mixing small measured quantities of said oil with small measured quantities of a refining reagent. at a temperature at which the oil is flowable but below an emulsion breaking temperature, incorporating in said mixture a suflicient separating said oil from the resulting sludge.

10. Anuick continuous process of refining animal and vegetable oils, which comprises, mixing small measured quantities of oil 11. The process 01' table oils, Wh10h comprises, mixing measured separation and promptly thereafter centriiugally separating said oil from vthe resulting sludge.

BENJAIWIN CLAYTON. BENJAMIN H. HURMANL

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