US2249702A - Process of refining glyceride oils and fats - Google Patents

Description

B. CLAYTON July 15, 1941.

PROCESS OF REFINING GLYCERIDE OILS AND FATS Filed Dec. 16, 1939 Wlmlavw lemployed for alkali reining prior Patented July 15, l9 41 PROCESS VF REFINING GLYCERIDE OILS AND FATS Benjamin clayton, Houston, Tex., lining-Inc., Reno, Nev.,

a corporation 0i' assign r to Reevada' Application lDecember 16h,A 1939, Serial Noi/7.309.674 l 20 calms. ,A (ci. aco-425) This invention relates to the reiining 'of lglycer-` Y ide oilsand fats. and more employment of high temperature treatment of the materials in the refining process. VIn the alkali refining of glyceride oils (the term oil will be herein employed as being generic to both oils and fats except where the context indicates otherwise), caustic alkalies, particularly caustic soda, have been employed in excess as the neutralizing agent. Caustic alkalies almost instantly neutralizes the free fatty acids in the oil, and no substantial excess is required for neutralization. However, a considerable excess of caustic soda over that necessary to neutralize the free fatty-acids -has ordinarily been employed in order to reduce the color of the oil and produce a separable soap stock. The excess particularly to the attacks the neutral oil. causing reiiningv losses due to saponlflcation thereof. For this reason the temperatures in such reiining processes have been maintained as low as possible' consistent with effective separation of the resulting soap stock from the oil. Even so, the entrainment of neutral oil in the soap stock in batch settling operations has been excessive, representing a major economic loss. and even in continuous processes in-f' volving proper conditioning ofthe mixture andcentrifugal separation, a considerable amount of neutral oil has been lost with the soap stock.

, 'I'he present process is particularly useful in the alkali rening of glyceride oils with nonsaponifying alkalies. Such non-saponiying alkalies, of which the alkali metal salts of weak acids are the mct common examples, do not saponify neutral o and losses dueto saponiiication of neutraloil are eliminated. However, nonsaponifying alkalies have not been commercially to the development leading up to the present` application and disclosed in certain of my copending applica-` tions hereinafter referredlto, although attempts have been made for many years to use the saine -gas formation resulted in :materials during batch e and. by occlusion of the neutralization. This violent foaming of the neutralizing reactions sas in the soap stock, lightened the saineV so asto render settling of the soapk stock impractical. Attempts have been made to employ dry soda, ash as the neutralizing oxide fend to form during agent or todry the mixture'of oil and soap stock,

to permit nltering the soap stock from the oil. These processes failed, because a sumciently neutral oil was not obtained with dry soda ash, andbecause the losses due to entrainment of oil in the lter bed were excessive.

In my copending applications Serial Nos.

259,502, 265,030 and 296,685, nled March 3, 1939, March 30,'1939 and September 26, 1939, respectively, I have shown how soda ash as well as other non-saponifying alkalies can be employed to suecessruuy refine glyceride ons and rats, for example, by using rating the resulting soap stock from the oil in the `presence oi' relatively large `amounts of soap in refining processes. Among the various reasons for failure of such prior processes are the slowness of the neutralizing reactions; inability to suiiiciently neutralize the oil for edible purposes,

i. e., reducing its free fatty acid. content to be-'.`

low 0.05 and preferably be1ow 0.03%; the inseparable nature of the soap stock obtained; and

the lack ofcolor reduction of the oil. v

Soda' ash is the cheapest and most available of the non-saponifyingalkalies, and many at tempts have been made to employ this material as a reining reagent. Boda ash has the further 'disadvantage that large amounts of Ecarbon ditheoretical minimum losses.

stock weighting agents. The present invention is a continuation-impart 'of the above mentioned applications and is directed to high temperature treatment of the materials in the process, and particularly to high temperature separation of the foots from the oil. In accordance with the present invention, the amount of soda ash or other non-saponifying .reagentv necessary forI neutralization and effective separation, or v"the amount of weighting agent present during separation, is markedly reduced. Effective color reduction is accomplished in addition to eiective neutralization and separation, so that a reiined oil of low color is produced' with almost the Since the oill is subjected to the high temperatures for short periods of time only, the oil. is not damaged by the high temperatures. e

It is, therefore, an object of the invention to provide a process of rening glyceride oils and fats in which separation of the foots from the `oil 1s accomplished by a 'difference in specinc gravity Y l at high temperatures.

Another object'of the present invention is to provide an improved process of refining glyceride oils and fats in which non-sapomfying neutralizing agents are employed.

Another object of the invention is to provide al process of refining glyceride oils and fats in which non-saponifying alkalies are employed in minimum amounts to produce reiined oils suitable for edible purposes and of reduced'color.

Another object of the invention is to provide large excesses thereof or sepa-f a continuous process of rening glyceride oils and fats in which the materials are subjected to high temperatures during the process in order to more` temperatures.

A still further object of the invention is 4to provide a process of refining glyceride oils and fats in which minimum amounts of soda ash are employed to produce neutral oils and in which refining losses are minfmized.

Other objects and advantages of the invention will appear in the following description of thev move at least a portion of any water or other volatile liquids from the mixture of oil and soap stock and also 'to remove other vaporizable or gaseous material such as carbon dioxide. In a preferred operation the vapors and gases are substantially all removed from the mixture above the liquid level 28' in the dehydrating chamber, l. e., the vapors and gases are flashed from the mixture. The mixture may be withdrawn from the chamber 2i by means of a pump 23 and delivered through a meter 30 to a flow mixer 3|. A weighting and rehydrating agent may be withdrawn from a tank 32, preferably provided with a heating coil 33 and delivered by a pump 34 through a proportioning cylinder 35 and heating coil 38 to the flow mixer 3|. 'I'he meter 3l md proportioning cylinder 35 may be entirely similar to the preferred embodiments thereof made in connection with the attached drawing, of which:

Figure 1 is a schematic diagram of an apparatus suitable for carrying out the process of the present invention; and

Figure 2 is a similar diagram of a modified apparatus.

The process will be first described with reference to the alkali refining of glyceride oils with non-saponifying neutralizing reagents to produce neutralized edible oils. Referring to the drawing: ill indicatesa tank constituting a source of supply fo the glyceride oil and II indicates a similar tank for neutralizing reagent. Oil may be withdrawn from the tank Il by means -of a pump I2 and delivered through a meter I3 and a heating coil I4 to a flow`mixer I5. Neutralizing -reagent may be withdrawn from thevtank II by A means of a pump I6 and delivered through a proportioning cylinder I1 and a1heating coil I8 to the mixer I5. The meter I3 and proportioning cylinder i'I-constitute a proportioning device for insuring that accurately proportioned streams of oil and reagent are delivered to the mixer I5. The meter I3 may be of any desired type, but is preferably a positive displacement meter, and is employed to actuate a valve (not shown) for controlling the admission and exhaust of the neutralizing reagent from the oppositesides of the cylinder I1 in which is positioned a free piston (not shown) driven by the neutralizing reagent. 'Ihe cylinder Il and associated valve and free piston may be'of the well known D valve construction conventionally used in proportioning mechanisms, an example of which is shown in Thurman Patent No. 2,142,062, granted December 27, 1938, and the valve thereof may be actuated by the meter I3 either directly through a connecting rod I! or through any suitable force amplifyingk mechanism.

The glyceride and neutralizing reagent are mixed in ow in the mixer I5 under pressure andout of contactV with the air. and then delivered through a heating coil into a vapor separating chamber 2I. A vacuum may be maintained in the chamber 2l by.' means of a vacuum pump 22 meter I3 and proportioning cylinder I1 previously described The mixture of oil and soap stock may mix withl the dehydrating and weighting agent in the mixer 3l land be delivered through a heat exchange coil 31 to a continuous centrifugal separator 38. 'I'he soap stock is separated from. the oil as the heavy eiiluent delivered through a spout 39 into a receiver 40, while thev neutral oil is delivered as the light effluent through a spout 4I into a receiver 42. The centrifugal separator 28 is preferably of the heated type disclosed in my patent No. 2,100,277, granted November 23, 1937. For high temperature operation, the centrifugal separator may also be of the completely enclosed type capable of operating under pressure so as to prevent liberation of a substantial amount of vapors or gases therein. Since, in the present operation, the oil discharged from the centrifugal 38 may be of high temperature, the receiver 42 is preferably closed except for a vent 43 in order to prevent contact of the heated oil with the atmosphere. If desired, the

operating through a condenser 23 and a receiver 24. A relatively high vacuum, i. e., from 27 to 30 inches'of mercury, is preferably maintained, although incertain instances a vacuum need not be employed in the vapor separating chamber.

receiver 40 for the soap stock may also be closed and provided with a vent 43. i For most oils and fats, the color of the oil is suiiiciently reduced in the steps heretofore described, but for highly colored oils or those resistant to color reduction it is sometimes desirable to give the neutral oil a caustic alkali wash in order to still further reduce the color thereof. For this purpose the oil may be withdrawn from the tank 42 by a pump 44 and delivered through a cooling coil 4I and a meter 46 to a iiow mixer 41. A color reducing agent, which is ordinarily an aqueous solution of caustic soda, although other materials such as sodium peroxide and equivalent potassium compounds may be employed, is withdrawn from a tank 4I and delivered by a pump 48 through a proportioning cylinder 50 to the mixer 41. The meter 43 and proportioning cylinder 5I. may also be entirely similar perature found most effective for separating the The mixture `of oil and soap stock is preferably l discharged against the walls of the vapor separating chamber 2l, for example by nozzles 25, The vapor separating chamber 2| may also be provided with a heating coil 23 and an agitator 27 driven by a motor 28. The vapor separating chamber and associated apparatus serves to recolor impurities from the oil is, in general, higher than the temperature for most effective color reduction reaction. The mixture is therefore preferably passed through a heating coll i2 and delivered to a continuous centrifugal separator 53. The color impurities and any excess color reducing agent are separated from the oil as 5 the heavy eiiluent and delivered through the spout 64 into a receiver 55. The oil is delivered as the light eilluent through a spout 6B into a receiver l and may be withdrawn from the tank 5l by a pump et and subjected to any desired further steps such as washing, vacuum drying,

` bleaching, deodorizing, etc. 1f the`color in the receiver 42 for the neutralized oil fromv the cenat relatively low temperature in batch inthe mixers 69 and 6l. The mixers 60 and El are intended to be used alternatively, so that the f mixture may be in the process of preparation in with agitators et driven from any suitable source' of power` through pulleys or gears 5l and are employed to thoroughly mix the neutralizing agent with the oil. After the mixture has been produced, the agitator may be employed to'maintain the same substantially uniform while a stream thereof is being Withdrawn. The mixturemay be withdrawn alternatively from the mixers du and di by a pump 88' and delivered through a meter 69 and a heating coil 10 to a flow mixer il. A weighting agent may be'withdrawn from a tank 'l2 which may be provided .templated in the present invention.

susceptible to be converted into a pressuretype centrifugal.' IBy merely providing a pressuretight connection between the rotating bowl and I.

the stationary. inlet pipe, it has been found that the resistance to discharge of oil and foots through their respective discharge ports enables considerable pressure to be' imposed upon the materials in the separator by delivering the mixture through the inlet pipe under pressure. Furthermore, the discharge ports referred to maybe throttled or the discharge pans of the separator can be made pressure tight and the discharge openings therefrom restricted so as to enable any desired pressure to be maintained in the separator. v The arrangement for heating the bowl of the separator may also be employed for imparting to' the mixture and particularly the foots being separated, a portion of the heat necessary for the high temperatures of separation con- However. lany suitable type of pressure centrifugal may be employed forcarrying out the present process.

with a heating coil 13 by a pump 'i4 and delivered through a proportioning cylinder i6 and a heating coil 'iii to the mixer 1i. The mixture from the mixer "il may be delivered through a heating or conditioning coil 'Il to a centrifugal separator le which may be of the same type as the centrifugal separator e3 ofv Figure 2. The soap stock is separated as the heavy eiiluent and may be delivered through a spout 19 into closed -receiver 8@ provided with a vent 80' and the Figure 2 delivered into the heating coil 20.0! Figure 1. This modified operation may, therefore, include'the steps of batchmixing, partial y or complete removal of water or other vaporizable 'or gaseous materials, 'rehydration and separation.

Furthermore, the continuous mixing step of Figure l may be employed in conjunction lwith the apparatus of Figure 2 by delivering the mixture from the mixer ib of Figure 1 to the heating coil l@ of Figu're 2. Also, in the process exemplified .by FigureZ, it is many times unnecessary to add a weighting material toproduce effective separation. Thus the mechanism including the tank 72, pump 1d, meter 69, proportioning cylinder le, coil le, and mixer 1l of Figure 2 may sometimes be omitted or disconnected.

In the preferred alkali refining process carried out in the apparatus of Figure 1, the glyceride may be any vegetable, animal or fish oil or fat, and the neutralizing reagent may be any non-volatile, non-saponifying neutralizing reagent. That is to say, practically any of the alkali metal salts having an. alkaline reaction such as the carbonates. phosphates, silicates, etc. of sodium or potassium. Since soda ash is the cheapest and most available of these reagents, the process will be particularly described with reference thereto. Furthermore, soda ash is perhaps the most diicult of the non-saponifying alkalies to employ and will best exemplify the novel nature of the improvement represented by the present invention. A substantial excess of soda ash over that necessary to neutralize the free fatty acids in the oil vwill ordinarily be employed, not only to insure complete neutralization but to effect color reduction. Thus, an amount of soda ash in at least twice the amount necessary for neutralization will -usually be employed, although in some instances in the process erably larger. It is entirely possible to use causlllilgure 1, and the mixture from the pump 68 of `vThe type of centrifugal -separator disclosed tic alkali in not more than the amount necessary to neutralize the free fatty acids and use soda ash or other non-saponifying alkali to neutralize any remaining free fatty acids and provide an excess. Since soda ash is considerably cheaper than caustic alkali. this expedient will not or- `dinarily be used, except in the case of extremely high free fatty acid oils. A small amount of sodium or other alkali metal peroxide can be advantageously addedl along with the soda ash so as to function lbath as a neutralizing agent and to liberate oxygen. The oxygen aids in reduction of .color of the oil in the vapor separating chamber. other oxygen liberating materials such as hydrogen peroxide may also be employed in condunction with a neutralizing agent. As an aid in carrying of! vaporizable materials, volatile liquids such as any of .the volatile alcohols or their esters or oil solvents such as'hydrocarbons can be mixed with the refining reagent or oil so as to be presentin the mixture entering the vapor separating zone. Buch materials can` be recovered in the condenser 24. and reused in the process.

As; shown in Figure l. both the glyceride and neutralizing reagent may be preheated in the in mypatent above referred to is particularly heating coils I4 and Il, respectively, prior to mixing, although in most cases substantially all of the heat will be applied after mixing the oil and reagent. If preheating is employed, the preheating temperatures may range from slightly above room temperature to temperatures as high as approximately 500 F. Even if preheating is used, it is many times possible to eliminate the heating coil Il for the neutralizing reagent. as the amount of neutralizing reagent represents a rather small proportion of the'total mixture and the mixing temperature will be relatively high, even though the neutralizing agent is supplied at room temperature. 1f caustic alkali is employed in conjunction with a non-saponifying altion, separation temperatures above approxb mately 160 F. have not been employed. The present invention, however, contemplates high temperature separation of the oil from the soap stock. Such temperatures will ordinarily run materially in excess of 212 F. but may be as low as 250 F. or as high as 500 F. The preferred temperature is `in the neighborhood of 300 F.. for example between 250 and 350 F. At the lower temperatures in the broad range given a substantially dry soap stock or a soap stock con- `taining very little water will not now continuously from the centrifugal separator. In such cases the vapor separating chamber can be operated under conditions to leave sufficient water in the mixture for effective separation or a rehydrating agent may be mixed with the de- F.. usually between 212 and`500 F. and preferably between 250 and 350 F., in the heating coil 2l. At these high temperatures the neutralizing reaction is rapid, even with non-saponifying alkalies, and a substantially completely neutralized oil can be delivered into the dehydrating chamber 2|. In a somewhat less desirable operation, the heating coil may be employed to impart only a portion of the heat to the mixture and the remaining heat may be supplied by the heating coil 20 positioned in the vapor separating chamber 2|.

It is preferred, however, to supply all or substantially all of the heat in the heating coil 2l. 'Ihe mixing and heating is preferably performed under superatmospheric pressure so that intro* duction of the mixture into the lower pressure zone of the vapor separating chamber 2| causes substantially all of the water, other vaporizable impurities and gas which it is desiredto remove. to be flashed from the mixture. 'I'he agitator 2l is employed to maintain a substantially uniform mixture in the vapor separating chamber 2|. Vapors and gases are preferably removed from the vapor separating chamber by the condenser 2l and vacuum pump 22. Any condensable material is condensed in the condenser I3 andrdelivered into the receiver 24 in order to assistl in maintaining a vacuum in the vapor separator 1|. A relatively high vacuum, for example 28 to 29 inches of mercury, is preferably maintained in the dehydrator 2|, although lower vacuums and even atmospheric pressure may in some instances be employed. The vapor separating chamber 2l may not only be employed to remove vaporizable material from the oil and produce a better quality oil. but also may be employed to remove any carbon dioxide'which may be formed as a result of employing soda ash or other carbonate for.

neutralization. It has also been found that complete or partial dehydration of the soap stock followed by rehydration in the mixer 3| `modifies the nature of the soap stock to produce more eilicient separation than is the case if the dehydrator is omitted asin Figure 2. Also. the color of the oil is further reduced than is the case in the process of Figure 2.

In the practical operation of processes prior to the development leading up to the present invenhydrated mixture in the mixer 3|. Excess non- `saponii'ying alkali aids materially in forming a separable soap stock. If suiiicient excess is mixed with the oil, in the neutralizing mixer i5. the weighting agent may be water alone, although an aqueous solution of an alkali metal salt is preferred. Either alkaline or substantially neutral salts may be employed. For example, soda ash constitutes an excellent weighting agent. Other non-saponifying alkalies such as tri-sodium phosphate, sodium silicate and also substantially neutral salts such as sodium sul fate, as well as equivalent potassium or other alkali metal compounds, may also be employed. Furthermore, soaps, particularly the more liquid soaps such as the sodium or potassium soaps of rosin or naphthenic acids or the potassium salts of fatty acids, aid in separation. It is possible to add these weighting materials with the neutralizing agent in the mixer l5, but, since it is usually necessary to rehydrate the mixture from the dehydrator 2|, they are more conveniently added in the mixer 3|, and less ma- 'ment of weighting agents less necessary, and in 45v many cases effective separation can be produced with small excesses of soda ash or other nonsaponifying alkali as the neutralizing agent with no additional weighting agent. Also. the amount of water necessary for rehydration is reduced over that described in my copendlng applications above referred to. At the higher temperatures of separation, the invention contemplates the centrifugal separation of dry or substantially dry mixtures as the high temperatures liquefy or at least soften both the gums .and the soap. At least a small amount of Water aids materially in separation however, for example, from approximately 1/2 to 3% water on the basis of the oil, depending upon the amount of free fatty acids and gums originally present in the oil, produces a mixture in which the water represents approximately 30 to 50% of the soap stock. With this amount of water, the soap is substantially insoluble in the oil even at high temperatures. In general, however, the greater the excess of soda ash or oi' weighting agent, the more water that is desirably employed. That is to say, water is desirably 4added in approximately-the same weight-as the additional soda ash or other weighting agent. Also, the

'lower the temperature of separation the greater vthe amount of water desirably present during separation. Thus. the water content may be as p nt of the oil rese .v

per pressures.

- The high temperatures contemplated in the present invention are possible as the oil is sub- :lected to these temperatures forvery short periods of time, so that substantially no splitting of the oil occurs. 'I'he non-saponlfying alkali does not attack the oil as would be the case if an excess of caustic were employed. Furthermore, an excess of caustic at lthe high temperatures referred to would degenerate or decompose the gums present in the roil and cause the same to be softened to an extent that a `substantial portion thereof would be soluble in or at least separate with the oil. Non-saponifying alkalies such as soda ash do not soften the gums to the same yextent as caustic soda. That is to say, much larger amounts of non-saponifying alkalies are necessary to produce the same gum oil being rened and its free fatty acid and gum which may. tend to form so as to form a carbonate. As stated before. even a limited amount oi caustic alkalies can be employed without 'attack on neutral oil. This additional alkali need not be added simultaneously with the carbonate but may be mixed with the oil either before or after the addition of the carbonate. By operating the entire system under pressure, including the centrifugal separators, any carbon .dioxide formed may be maintainedin solution in 'water, that is to say, in the form of carbonio acid. When the dehydrator is omitted as in Figure 2, it is ordiof vapors in the separator.

The exact temperature of separation content, but "as stated above, will usually range from 250 to 500 F. and preferably is in the At separation temperatures substantially above v 212 F. the water present in the mixture will tend to dash into steam in the centrifugal separator and cause soap stock to remain in 'the oil. It has been found, however, that separation is not Vinterfered with even at temperatures considerably above 212 F., as the pressure at the zone of separation in a centrifugal separator is several hundred pounds persquare inch. With centrifugals having an inlet open to theatmosphere steam will be formed in the inlet portion, if

water is present, but this may be prevented by employing enclosed pressure type centrifugals capable of being operated under pressure suili- 'cient to retard the formation of steam, which pressure may y range from a few 4pounds per square inch at the lower temperatures up to several hundred pounds per square inch at the up- Since soda ash reacts very slowly, if at all, with v free fatty acids at low temperatures, for example room temperature, the soda ash may be mixed with the oil in batch, as shown in Figure 2. Ex-

cessive foaming due vto the formation of carbon dioxide is avoided,ar 1d the mixture may be rapidly heated in the heating coil 10. At elevated temperatures, for example temperatures above 200 F., the neutralizing reaction is quite rapid and the oil is rapidly neutralized in the heating coil .10. The resulting mixture ispreferably passed through the second'coil 'I1 to condition may be prevented in several ways. For example,

The process above described materially reduces 4the color of the oil, but if necessary the oil may be given acolor reduction wash. Color reduction reactions with caustic color reducing agents are, most effective at relatively low temperatures,

for example, temperatures between and 100 F. it is therefore desirable to cool the oil in the cool- -ing coil lli to a temperature not substantially above F. prior to mixing the color reducing agent therewith. 'I'he colorreducing agent preferably comprises a caustic soda solution having a concentration'of from, for example, betweeny 10 and 30 B. The amount necessary for color reduction will vary for .different oils, but may be as low as 11s of 1% up to approximately-3%. In

many cases it is desirable to provide a short time for color reduction reaction at the low temperature in a treating `coil 5I. lThe mixture is then preferably rapidly heated to a temperature between approximately and 160 F. and continuously centrifugally separated in the separator 53. In such a treatment, it has been found that theA caustic does not materially attack the oil and that no substantial amount of oil'is entrained with the color impurities. Thus, the losses in this portion of the system may be as low at of 1% or lower.

'I'he amount and concentration of the reilning reagents employed in the process will vary widely in accordance with the nature of the oil being refined, i. e., the source vofthe oil. the-.amount and type of free-fatty acids and the amount and type of gums and coloring matter. as Well as the temperature -of treatment and separation, and

y the type of rening agent. In general, the more at least twice as muchV soda ash is required for neutraiizationof the 'free fatty acids may be employed.l Suillcient other alkali may be used in the process to combine with any carbon dioxide highly colored oils require a greater excess of .refining reagent if color reduction is desired. However, the high temperatures minimize theexcess required for color reduction and separation. Thus, for producing a neutral oil, amounts of neutralizing reagent from just slightly more, i. e., 5 or 10%, than that theoretically required for reaction with the fatty acids up to excess of several times the theoretical amount may be used. l The high temperatures also minimize the amount precipitate gums and coloring matter with high y temperature treatment. At the lower temperatures more dilute solutions of refining reagent tides present l posed to the are usually desirable during neutralizing and the Y be employed to produce partial refined oil auch as"degummed" or non-break" oil still containresume agents in 'siksu'rennma with non- Y saponifying alkalies there is no loss of neutral l oil duetto saponifleation thereof.

ing free fatty acids but useful for many purposes other than for edible products. Also, substantially neutral salts or slightly acid reagents can be employed to precipitate gums either in substantiallyrdryor in aqueous solution to make a degummed" oxnon-break.4 oil. Even acid refining wherein strong mineralacids are used to render gummy matter vseparable from the oil can be practicedby the present invention. The high `temperature conditions rapidly complete any reactions which take place and render the foots separable in the presence of a minimum amount of refining reagent and water before the oil has been damaged. Y

A major advantagey of the' present invention when applied to alkali refining with non-saponifying alkalies is the excellent quality of the soap stock which isproduced. The present invention enables a smaller amount of alkali to be employed so that materially less acid is required to release vthe combined fatty acids. The small amount of water in the foots render them'less bulky and more stable against fermentation. Furthermore, at the higher temperatures of separation, the release of the soap stock inw atmospheric pressure from a pressure centrifugal causes all or a portion of the water to be vaporized and separated from the soap stock. With non-saponiiying alkalies, certain valuable'constituents of the gums, for example, the phosphain vegetable oils, are not decomextent that this occurs 'in known processes of renning with caustic alkalies. This is particularly true when the temperatures in the rocess are maintained in the lower portion of the range givenfi. e., below approximately 300 or 325 l". V

One way of operating the process of the present invention particularly with non-saponifying alkalies such as soda ash. is to mix the renning agent with the oil and partially or substantiallir completely dehydrate the mixture in the vapor separating sone vat relatively low temperatures,

for example temperatures between 160 and 250' 1"., then introducing into the mixture a rehydrating agent which may be either wat'er alone or a'solution o! soda ash or other non-saponifying alkali, depending upon the amount of renning agent initially added. The rehydrating agent may be at the same temperature. at a lower temperature or a higher temperature than Athe mixture to which it is added. Thelatter is ad vantageous since the rehydrating agent may serve to elevate the temperature of the resultant mixture to condition it for separation. The resultant mixture may also be further added to produce the desired temperature of separation which will usually fall between 250 and 500 F., and preferably between 250 and 350 Il'. TheV relatively low temperature of dehydration produces a soap stock in which the gums are more easily rehydrated than is the case where higher ternperatures of dehydration are employed. As a result somewhat lower temperatures and less dehydrating agent can be employed during separation while still producing a liquened soap stock.

The maior advantage of the present invention odorizlng, bleaching, etc.

While I have disclosed the preferred embodi- -ments of my invention, it is understood that the kdetails may be varied within the scope of the following claims:

What I claim is:

1. The process of refining glyceride oils and fats, which comprises, mixing a refining agent with said glyceride to precipitate foots, and separating said foots from said glyceride by difference in specific gravity at a temperature in excess of 200 F. and below 500 F.

2. The process of refining glyceride oils and fats, which comprises, mixing a refining agent with said glyceride to precipitate foots, and separating said foots from said glyceride by difference in specic gravity at a temperature between approximately 250 and 500' F.

3. The process of rening glyceride oils and fats, which comprises, mixing a refining agent with said glyceride to precipitate foots, and separating said foots from said glyceride by diffference in speoic gravity at a temperature between approximately250 and 350 F.

4. 'Ihe process'of refining glyceride oils and fats, which comprises, mixing a refining agent with said glyceride to form a mixture of glyceride and foots, continuously centrifugally separating said foots from said glyceridey at a temperature between approximately 250 and i500 F., and maintaining said mixture under sumcient pressure during said separation to prevent liberation gif vapors or gases interfering with said separaon. 5. 'Ihe process ofreiining glyceride oils and fats, which comprises, mixing a refining agent with said glyceride to form a mixture of glyceride and foots, continuously centrifugally separating said foots from said glyceride at a temperature between approximately 250 and 350 1"., and maintaining said mixture under sumclent pressure during said separation to prevent liberation of vapors or gases interfering with saidV separation.

6. The process of refining glyceride oils and fats. which commises mixing a refining agent separator at a temperature above 200 F. and

is the savings in refining losses and in costs oi.' 75

suiiiciently high to cause said foots to continuously flow from said separator.

"I, The process of refining glyceride oils ,and fats, which comprises. mixing a non-saponiiying neutralizing agent with said glyceride and forming la mixture of glyceride and soap stock containing insuiiicient water to produce centrifugally separable soap stock at a temperature below P., and continuously centrifugally separating said soap sto'ck from said glyceride in a continuous centrifugal separator at atemperature above 200 I'. Vand below 500' F. but sumciently high to cause said -soap stock to'A continuously ,flow from said separator. v l

8. The process of refining glyceride oilsand fats, which comprises, mixing a. non-saponifying neutralizing agent with said glyceride and forming a'mixture of l'glyceride and soap stockf-'con-f taining insumcient water to produce centrifugally separable. soap stock at a .temperature 'below 160 F., and continuously centrifugallyfseparating said soap stock from said glyceride in a,c9ntinu.

ous centrifugal separator at a temperature between 250 and500 F;

mntely'zsoand 500 r., and maintaining ma mixture under pressure and instream flow from thejpoint of neutralization of saidl free'fatty acids until separation has been completed.

14..'1he-process of refining glyceride oils and fats, which comprises, mixinga refining .agent with said -giyceride, heating a flowing stream ofthe resulting mixture under pressure and out off;coxita t l with the airto a temperature between 250 4and 500 F.,'and continuously centrif- "ugallyfseparating the resulting foots from said 9. The process or refining, glyceride ousand fats, which comprises, mixlngfsoda ash with said glyceride and forming a' mixture ofglyceride and soap stock containing insumcientwater to produce centrifugally separable soap stock ata tem' perature below 160 F., and continuously centrifneutralizing 'agent with said glyceride to form a mixture of glyceride and soap stock, continuously centrifugaily separating said soap stock from said glyce'ride at a temperature between approximately 250 and 500 F., and maintaining saiplxture under sufficient pressure during said -se tion to prevent liberation of- -vapors'or gases interfering with said separation.

11. The process of refining glycende oils and fats, which comprises, mixing soda'ash with said foots, continuously centrifugally separating said .A

.foots from said glyceridg,i at a temperature be- ,tween approximately 250 and 500 F., and main- .tainlngs'aidmixture under sufilcient pressure during said separation to prevent liberation of iapors o'r gases interfering with said separation.

12. The process of renning glyceride oils' and fats `containing free -fatty acids. which com.

prises. mixing -a non-saponifying neutralizing agent with said glyceride to neutralize said free been completed.

' 1s. 'me process orv feaning glycerin@ ous and fats containing freelatty acids, which comprises.

said .fees atty acids and 'form a mixture" of glyccsldemd asap stock, continuouslycentrifusally separating said soap stock glyceride at a temperature between approxi- .mixingsoda ash--withtaidglyceride to neutralize glyceride at said temperature.

v .15. The process of rening-.glyceride oils and fats, which soda ash-with .said

-lgglyeerigefaeaunga sowing stream o: the resulting mixture under pressure and out of contact with the air 'to .a temperature between 250 and 500 E, and continuously centrifugallyseparating the resulting soap stock from said glyceride at said temperature. Y

16. The process of refining glyceride oils and fats, which comprises, mixing a refining agent with said glyceride, heating a flowing stream of the resulting mixture under pressure and out of contact with .the air to 'a temperature between 250 and 500 F., subjecting said mixture to a dehydration treatment, and continuously centrifugally .separating the'resulting foots from said glyceride at said temperature.

17. The process of refining glyceride oils and fats, which comprises, mixing soda ash with said glyceride, heating a flowing vstream of lthe re' sulting mixture under pressure and out of contact with the air to a temperature between 250 and 500 1".. subjecting said mixture to a dehydration treatment, and continuously centrifugally separating the resulting soap stock from said glyceride at a temperature sumciently high toy cause saidsoap stock to flow Acontinuously from the centrifugal separator employed.

18. Ilhe process of rening glyceride oils and `ats whichv comprises: mixing soda ash with said glyceride to form soap stock, conditioning said soap stock for the act of centrifugal separation by the presence of heat suilicient to provide a temperature` of said soap .stock above 200 F. and sulclent to liquefy the soap stock and separating the thus liquefied soap stock from the rened Oil.

19. The process as dennen 1n daim; 1a 1n which the soda ash added during the process is at least several timesa that required to neutralizae the free fatty. acids.

20. The process as defined in claim 18 in centrifugal separation.

CERTIFICATE OF CORRECTION. Patent No. 2,21I9,7O2. July 15, 19in'.

v BENJAMIN CLAYTON.

It is hereby certified that Ierror appe'rs .in the print'ecl specification of the above numbered patent requiring correction as follows: lPage l, first column, line ).Ljhfor the word "reactions"rcad'f--reaction--q page 2, second column, .line 20, for "dehydrgting" rea'df-renydrating--g line 42.)-1, fter ".ffluent" ins'erf -I-and--j page 5, first column, line '(2, for is read. --sf--g and second "column, line l|.9, for "at" rea@ as -and'that' the said Letters# ,Patent should be rend this con' action therein 'that choA same may conform to th rocord of the A4case in ..1;1f1-e 'i?rat'enjb` Office.

signed and Sealed this. 25rd d ay of' septexgber,...pg 19141.

Van Arsdg'le',

(Seal) l Acting'fc'ommisvsioner of Patents."

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