USRE22006E - Hydrolysis of fats and oils - Google Patents

Description

Jan. 13, 1942- M. H. :TT R 22,006

HYDROLYSIS OF FATS AND OILS Original F ilpd June 6, 1956 INVENTOR 9 a ga-a4 v ATTORNEYS water. cause fats andfatty oils stored in the presence Reissued Jan. 13, 1942 Re. 22,006 a HYDBOLYSIS F FATS OILS- Martin Hill Ittner, Jersey City, N. 1., assignor to Colgate-Palmolive-Peet Company, Jersey City, N. J., a corporation of Delaware Original No. 2,139,589, dated December 6, 1938, Serial No, 83,991, June 6, 1936. Application for reissue November 30, 1940, Serial No. 368.060

6 Claims. (Cl. 260-415) This invention relates to animproved process for'the aqueous hydrolysis of fats and fatty oils to produce fatty acids and glycerin.

Fats and fatty oils as they occur in nature consist of triglycerides, that is, compounds in which one molecule of glycerin has been combined with three molecules of fatty acid with the elimination of three molecules of water. It is the object of this invention to provide an improved process for splitting or hydrolyzing such triglycerides into fatty acids and glycerin, with the production of a relatively concentrated aque-' ous solution of glycerin and relatively pure fatty acids uncontaminated by decomposition products or tars or by catalytic materials or reaction products of catalytic materials.

The saponiflcation of fats and oils with caustic It has also been proposed to accomplish the aqueous hydrolysis of fats and fatty oils by heating the fats or fatty oils together with liquid alkali in excess, or in the proper proportions to combine with the fatty acids produced, has long been used in the manufacture of soap. Glycerin is produced at the same time that the soap is produced, but the removal and purification of the glycerin involves a number of relatively expensive operations.

, The aqueous hydrolysis of fats and fatty oils, by the use of water and catalysts of various types has also been known and used for a long time. Y Included among the catalysts which have been 'promote surface-contact between fat and water.

, Another method of accomplishing the aqueous hydrolysis of fats and fatty oils is the well known 'I'witchell process in which the fat or fatty oil water at comparatively high temperatures, and

at pressures sufficient to prevent the formation of steam inv contact with the mixture being heated, with the production of an aqueous solution of glycerin and the fatty acid. i

In all such procedures which have been used or proposed heretofore, balanced reactions which go to an equilibrium result, and the saponification or hydrolysis, as the case may be, is incomplete, except with repetitions of the treatment. Except under very favorable conditions, the saponification 'or hydrolysis seldom proceeds as far as 90% completion. By removing the aqueous solution of glycerin formed and subjecting the fatty matter to repetitions of the treatment, the saponification or hydrolysis may be brought up to 95% of completion, or, under favorable conditions, somewhat higher. Furthermore, agitation and protracted treatment are required to so complete the reaction, and the heat losses which take place because of the repetition of the treatment and the length of the treatment become excessive. If water is not used freely in carrying out the reaction, the saponlfication or hydrolysis is retarded; and ii water isusedfreely, or if many changes of water are used, the glycerin obtained is objectionably diluted, and expensive to evaporate and concentrate. Also, where the is brought into contact with water and one of extent in the fat or fatty oil, at the boiling point of water.

It is also known that fats and fatty oils hydrolyze to some extent when in contact with water alone at relatively low temperatures, e. g., temperatures up to about the boiling point of This hydrolysis, while sufficiently fast to of moisture to deteriorate, is too slow to be of value for the commercial hydrolysis of fats and fatty oils to produce fatty acids and glycerin.

treatment is prolonged or repeated, there is an increase in the darkening of the fatty acids and the formation of undesirable tars. This is particularly true in the processes in which catalysts are used.

' Where catalysts are used to hasten the saponiiication or hydrolysis, the products produced are contaminated by the catalysts and special treatment is required to remove the catalysts.

As an illustration of the fact that these hydrolyses or saponifications as commonly carried out are balanced or reversible reactions which do not go to completion even at high temperatures and pressures. I have determined that if a mixture containing 35 parts of pure neutral tallow and 25 parts of pure water is heated under pressure in an autoclave to about, 255 C. for about 3 hours, or until an equilibrium is reached,

a product is obtained which is about 92% hyf an autoclave to 255 C. for 3 hours and at the same pressure as employed in the test described above, an esterification takes place with the formation of glycerides and with the production of Similar experiments with cocoanut '11 peratures and pressures, longer periods are required for the reaction to reach an equilibrium point, and at equilibrium the hydrolysis is con siderably less.

The fact that this reaction is one which pro ceeds to an equilibrium, and not to completion,

drolysis'of fats and fatty'oils in a single oper-v ation and within a relatively short time and with marked. heat economy, with theproduction of relatively concentrated aqueous glycerin and fatty acids uncontaminated by.catalysts or other objectionable impurities requiring special treatment for their removal, and without the objectionable decomposition and formation of tars heretofore frequently encountered when carrying the hvdrolysis even to a lesser extent than that to which I carry it.

I have found that, although the solubility of water in fats and fatty acids is very slight at low temperatures, and at temperatures as high as the boiling point of water at atmospheric pressure or even considerably higher, the solubility of water in fats and fatty oils and fatty acids in the presence of excess water, under sufficient pressure to prevent the vaporization of the water, increases slowly up to about 200 C. and then increases more rapidly at higher temperatures.

In all cases, to dissolve any considerable amount,

of water in the fats or fatty acids a pressure in excess of the pressure of saturated water vapor at the temperature selected must be used. For example, at a temperatureof 235 C. and an absolute pressure of 700 pounds per square inch,

fatty acids from cocoanut oil will dissolve about 17% of their weight in water in the presence of excess liquid water. The same fatty'acids, in the presence of excess liquid water, and at a temperature of 245 C. and an absolute pressure of 800 pounds per square inch dissolve about 20% of water. At a temperature of about 287 C. and a pressure in excess of atmospheres, these fatty acids blend freely with more than their own weight of water with the formation of a single,

clear liquid phase. Other commercial fatty acids,

such as those from tallow and palm oil, behave in a similar manner and have an increased power to dissolve water at elevated temperatures and pressures such as those above referred to.

In accordance with the present invention, I subject the fat, fatty oil, or mixtures thereof to be hydrolyzed to the action of liquid water at high temperatures and pressures. The process is carried out by contacting the fatty material with the water by countercurrent flow under such conditions as to insure intimate contact of the fatty material with the water, with prevention or minimizing of emulsification, and with the use of temperatures and pressures sufilciently high to insure that an amount of water appreciably in excess of the amount of water required for the complete hydrolysis of the fatty material to fatty acids and glycerin is dissolved in the fatty-material, but not so high as to produce miscibility of the fatty material and water, or to cause the fattymaterial to dissolve all of the water used with the production of a single liquid phase. The amount of water required to be dissolved in the-fatty material varies with different fatty materials, but in each case, for the rapid hydrolysis of the present invention, must be apprecia-bly greater thanthe amount required for hydrolysis. For example, cocoanut oil for complete hydrolysis requires about 8.3% of its own weight of water and tallow requires about 6.4% of its own weight of water. For this rapid hydrolysis of these fats, the effective conditions of temperature and pressure are such that the fatty material dissolves considerably more water than these amounts. The water dissolved in the fat affects the saponification and any excess water not dissolved washes out glycerine so that the saponification may thus be carried to completion.

- The totalamount of water used in carrying out my process must be sufiicient not only to provide the necessary amount of water for the hydrolysis, and any excess water dissolved in the fatty material at the high temperatures and pressure employed. but also sufficient to dissolve th glycerin formedand remove it from the fattyv fied and the water, the pressure maintained in the apparatus is well in excess of the pressure of saturated steam at the highest temperature se-- lected, so that ordinary variations in temperature and pressure cannot result in the vaporization of 'water within the apparatus to interfere with the operation of the process. The apparatus is kept completely full of liquid, that is, fatty material and water or aqueous glycerin.

It is important, in carrying out the process, to provide for the proper separation of the aqueous glycerin from the fatty material at the point where the aqueous glycerin is removed from the apparatus, and to provide for the proper separation of the fatty material, that is the fatty acids resulting from the hydrolysis, from the water at the point where the fatty acids are withdrawn from the apparatus. This is accomplished by providing settling spaces or zones adjacent to the parts of the apparatus at which these materials are removed, so that where the aqueous glycerin is separated or removed from the appaan economic rate of operationas the fatty material is very prone to objectionable emulsiflcation the fact that the temperatures andpressures are sufliciently high in my process to cause a very considerable amount of water to actually dissolve in the fatty matter, agitation is not needed to promote saponiiication but leads to emulsification that is generally considered as desirable, if not necessary, to increase contact in other methods employing temperatures and pressure not sufficiently high to cause a considerable degree of solubility of water in the fatty material. Emulsification in any part. of the apparatus lessens the efllciency of the process and emulsiflcation of inflowing fat with aqueous glycerin or of outflowing fatty acids with infiowing water besides disturbing the smooth operation of the process also introduces an indefinite and irregular factor in the proportions of reacting materials remaining in the apparatus.

While the process can be carried out over a fairly wide range of temperatures, which varies with different fatty materials, and over a fairly wide range of pressures, which more or less depends upon the temperatures selected, the temperatures used, and the corresponding pressures used, must be such that two separate and distinct liquid phases are maintained within the apparatus, one phase being the fatty material, that is, the fat or fatty oil, or the fatty acids. or partially hydrolyzed fatty material, containing a proportion of dissolved water somewhat greater than the amount of water required for the complete hydrolysis of the fatty material, and the other phase consisting of water or aqueous glycerin, sumcient in amount to effectively wash out the glycerin from the fatty material and carry it through the apparatus, to be removed as aqueous glycerin ranging in concentrations from or less up to 50% or more. Stirring or emulsiiication defeats the washing by preventing the ready separation of the aqueous glycerine phase from the fatty phase and eflicient washing out of glycerine. The pressure selected depends upon thantheir own weight of water to form a single clear liquid phase, instead of the two phases required for the properoperation of my process.

Similarly, with each fat or fatty oil, there is an upper temperature limit beyond which the solubility of the water inthe fatty material is too great to permit the process to be carried out.

In general, I find that temperatures somewhat above about 200 0., or a little below 200 C., are

satisfactory, in that at such temperatures the solubility of the water in the fatty material is quite appreciable andis in excess of the amount required for the hydrolysis of the fat or fatty oil, but is not so great as to cause the formation of a single liquid phase in the apparatus or to render the water so soluble in the fatty material as to preclude the proper washing out of the glycerin, at least with a reasonable amount of water.. At lower temperatures, water is not sumcientiy soluble in the fatty material to allow the Process to be economically carried out, and. the

desired hydrolysis cannot be obtained at such lower temperatures in apparatus which does not depend upon mixing and large surface contact, at least in a reasonably short time and with the production of concentrated aqueous glycerin subgiven for carrying out the process, inasmuch as the temperatures vary with diiferent fats or fatty oils, I have found that cocoanut oil, for example, canbe advantageously treated at temperatures of around 23 C. 0'! 245 C. and at pressures ranging about 250 pounds, more or less, in excess of the pressure of saturated, steam at these temperatures and that other fats and fatty oils may be advantageously treated at similar temperatures and approximately similar excess pressures. At temperatures of about 287 C. or'higher and-correspondingly high pressures, I find that the process cannot be carried out with cocoanut oil, as at these high temperatures and pressures cocoanut oil fatty acids blend freely with more 'stantially free from fatty material.

action of fatty acids and water at high temperatures and pressures and of sufficient strength to withstand the high pressures used with an ample margin of safety. The arrangement of the apparatus is such that the fatty material and water or aqueous glycerin, which flow countercurrently, are in intimate contact over a relatively long path and do not have a tendency to emulsify to any great extent. It is advantageous to cause the fatty material to flow upwardly through the vessel or vessels while the water or aqueous glycerin flows downwardly in intimate contact with it.

, Where a single pressure vessel is used, it is provided on the inside with a number of trays or other suitable devices to insure intimate contact of the fatty material and the water or aqueous glycerin and to insure that this intimate contact is suiliciently prolonged to provide the desirable washing of glycerine from the fatty material which leads in the substantially complete hydrolysis of the present invention. Where a plurality of pressure vessels is used, the trays or ptherdevices are not necessary, as the length of' the path over which the materials flow in contact is sufficient to accomplish the necessary intimacy and length of contact, but trays or similar devices may be provided with advantage if desired. v

The apparatus is also provided" with suitable heat exchangers. so that the heat contained in used for this purpose. Suitable unitary heating units. such as electrical heaters properly placed around the exterior of the apparatus so that heat can be supplied to the apparatus where desired pumps to introduce the water and fatty oil or fat under the high pressureused, and with suitable gauges and thermometers and suitable safety devices such as safety valves and the like to control the pressure and temperature within the apparatus.

It is preferable to maintain the apparatus nearly full of the lighter fatty material and to maintain below the fatty material a settling zone for the separation of the aqueous solution from the fatty'materiai. The apparatus is therefore provided with a suitable means of determining the position of the interface between the fatty material and the settling zone containing the quiescent aqueous glycerin near the point where the aqueous glycerin is removed, and near the point where the fat or fatty oil is introduced. The determination of the location of the oil or fat and water interface may be accomplished by means of a gauge glass suitably located near the bottom of the apparatus, or by providing a number of small faucets or outlets near the bottom of the apparatus in vertical series.

. The invention will be further illustrated by reference to the attached drawing, which illustrates an apparatus adapted for use in carrying out the with the insulation removed showing the positioning of the electrical heaters used to provide I suitable heating to offset losses by radiation;

Fig. 5 is an illustration of one type of heat exchanger which may be used; and Fig. 6 illustrates a diphenyl preheater which may be used.

In Fig. l are shown four suitable pressure vessels It, II, I! and I3 arranged in series. Fatty material is introduced into vessel ll through inlet and water into vessel I3 through inlet ll,

' the fatty material and water thus having a countercurrent how. The fatty material arises in vessel l0 and flows outthrough pipe It to enter near the bottom of the second vessel through which it flows in an upwardly direction and out through pipe I! to enter the third vessel l2 near the bottom, from the top of which it flows through pipe Ila to the fourth vessel ll. The water flows downwardly through vessel II, hydroiyzing the fatty material and dissolving glycerin, and flows out of this vessel through pipe II to enter the next vessel near the top,'iiowing downwardly countercurrent to the fatty material through this vessel, and then passes to the next vessel, etc. Each of these vessels is provided at the bottom with a quiescent settling zone in which is maintained a layer of dilute glycerin or water and in which the aqueous glycerin separates from the fatty ma-- terial to be withdrawn free from fatty material aaooo except for that dissolved and at the top with a similar quiescent zone for the separation of the fatty material from the water or aqueous glyeer- .replaced or supplemented by gauge glasses of suitable strength and construction. Faucets or outlets 21a may be provided near the middle and top of the vessels for drawing samples. These pressure vessels may be advantageously grouped together and placed within. a large shell to minimize heat losses. If desired, the interior of this shell may be heated as by means of hot gases to insure the maintenance of uniform temperatures within the pressure vessels; or if desired. the shell may be dispensed with, and suitable unitary heaters, such as hereinaitervdescribed in connection with Fig. 4, may be provided on each of the pressure vessels. Trays may be provided within each of the pressure vessels to lengthen the path over which the materials flow, and to increase the intimacy of contact between the materials if desired, in order more effectively to wash glycerin from the fatty acids and water dissolved therein.

One suitable construction of the interior of a pressure vessel is illustrated conventionally in Fig. 2, the parts not being to scale. In this figure the vessel 22 may be, for example, two feet in diameter and fifteen feet high and may be made of suitable pressure-resistant and corrosion-resistant material, such as stainless steel. It is shown as provided with a series of trays 23 and 23a, with the alternate trays 23a having a diameter the same as or somewhat less than the interior diameter of, the vessel, and intermediate trays 23 of smaller diameter, as shown. These trays may be spaced, for example, about one inch apart, more or' less, but are shown as proportionately further apart, for convenience of illustration. These trays are suitably supported by rods or other devices (not shown) and are so constructed and arranged as to cause the material passingthrough the vessel to follow labyrinthian paths, to increase the eillciency of the excess liquid water in washing glycerin from the fatty acids.

The alternate trays II are shown as'of materially less diameter than the inner diameter of the vessel and as provided with rims at their outer peripheries over which the material flowing downwardly, that is, the aqueous glycerin or water, must flow; while the other trays 53a which 7 are shown as having the same diameter as the inner diameter of the vessel, but which may advantageously have a somewhat smaller diameter to allow for clearance and expansion, are also provided with outer peripherial rims and with openings at the center through which the water or glycerin must flow in its downward path. The fatty material, rising through the vessel, follows the reverse path.

At the bottom of the vessel is shown the settling zone 2|, in which the aqueous glycerin is separated from the fatty material. The aqueous glycerin, after proper separation. is removed through outlet 24, while the fatty material is fed to the apparatus through inlet ll to a point advantageously above the lower trays and above the interface of the fatty material and the aqueous glycerin or water in the settling'zone.

A somewhat similar zone It is provided at the top of the vessel for the separation of the fatty material from admixed water, so that the is material may be removed from the vessel free from any water except dissolved water. The fatty material, after proper separation, is removed through outlet 21 while water is introduced near the top ofthe vessel through inlet II to a point adjacent to the top tray of the vessel and below the separating zone. Faucets or outlets may be advantageously provided near the bottom of the vessel to permit the determination of the position of the interface between the settling zone of aqueous glycerin and the fatty material.. These faucets or outlets may be replaced or supplemented by a gauge glass of suitable strength and construction. Faucets or outlets Il may also be provided at the middle and near the top of the vessel for drawing samples, and a safety valve 31 is also provided. v

The vessel 22 is made of sufilcient strength to withstand the high pressures and temperatures usedin the process with an ample margin of safety and is advantageously made oi a lower shell 29 and an upper dome 30 advantageously provided with a suitable pressure-resistant gasket 32.

In Fig. 3 is shown another modification of the trays which may be used within the pressure vessel of Fig. 2 to provide the necessary long path for the. material to insure the necessary intimacy of contact and completeness of reaction. In this 1 modification, the holes in the trays 32 are made without rims, alternate trays being provided with contained in the fatty acids and aqueous glycerin taken from the apparatus, will be further heated by a suitable means, such as by a diphenyl heater as illustrated in Fig. 8. The apparatus will also be provided with eflicient insulation to conserve heat, and with suitable thermometers, such as thermocouples, located at various places throughout the apparatus to enable thetemperatures of the maerial in the apparatus at various points to be determined and to enable the proper control of such temperatures. The apparatus will also be provided with suitable valves for control- I ling the input of water and fatty material, and

for maintaining the pressure within the vessels at the proper point. Suitable pumps to force the water and fatty material in under the high pressures used will also be provided.

Inoperation, fatty material, such as cocoanut oil or tallow, is continuously introduced to the apparatus shown in Fig. 1 through inlet it after,

passing through a preheater such as that shown in Fig. 5 and through a heater such as shown in Fig. 6 to heat it to the temperature used in the operation, advantageously to a temperature of about 235 C., a pump being used to force it in under a high pressure about 200 pounds in excess of the pressure of saturated steam at the same temperature. At the same time, the proper amount of water, suitably preheated, is continopenings near the outer periphery while the other trays are provided with openings at the center; the water thus flowing downwardly in a labyrinthal path, while the fatty material flows upwardly following a reverse path. In Fig. 8, as in Fig. 2, the trays are shown spaced apart, for convenience of illustratiombut may be, e. 3. one inch apart in a vessel two feet in diameter. All of the holes in the trays, which may vary in location and arrangement, may have slight lips or rims to retard the, downward flow of the aqueous liquid.

Fig. 4 shows an arrangement by which the pressure vessel of Fig. 2 may be heated to counterbalance losses due to radiation and the like. This figure shows how, on the exterior of the vessel, there may be provided a number of electrical heating units 33, with electric connections 34, arranged in zones, so that heat supplied to various portions of the vessels, that is, the heat supplied for example to the upper portion and to the middie portions of the vessels may be varied inderangement of electrical heating units arranged in zones may be used for heating the pressure vessels of the apparatus shown in Fig. 1 if desired, and if it is not desired to group all of the vessels within a single shell, or the pressure vessels may have such electrical heating units even when included within a large shell, thus dispensing with the necessity of heating the interior of the shell, with the shell serving to cut down heat losses by radiation and convection.

It is to be understood that suitable heat exchangers for the fatty material and water fed. to the apparatus will be supplied, such heat Vexchangers as those shown in Fig. 5 being suitable,

and that the material fed to the apparatus, after uously introduced through opening it of vessel i3 near the top. The fatty material introduced through opening it passes up through the pressure'vessel Ill, being separated from the water or aqueous glycerin in this vessel in the quiet zone provided at the top of the vessel, and then is introduced, by pipe it; near the bottom of vessel il free from all water except that dissolved in it and thus passes through the iourvessels in series. The saponification becomes more complete as the fatty material progresses, and it comes into contact with water containing less glycerin as it progresses through the apparatus so that there is a strong tendency for the hydrolysis to reach completion the absence of glycerin or its presence in but very small amounts in the later stages tending to drive the reaction to completion. -At the top of each of the vessels the fatty material is separated from the undissolved water or aqueous glycerin, and is removed containing only dissolved water. It is removed from the last vessel through outlet 40, and then led to the heat exchangers where its contained heat is used to preheat entering material and where it is cooled to a sufllcient extent so that the pressure may be released and the fatty acids exposed to the atmosphere without damage.

the vessel II through the other vessels and finally through the vessel ii, a quiescent or settling zone being provided atthe bottom of each vessel so that the water and dissolved glycerin are sep-,

arated from the fatty material and pass from one vessel to the next with no fatty material except that dissolved. From the bottom of the vessel In, an aqueous glycerin solution having a concentration which may range from 15% or less to 50% or more is taken. The concentration of the glycerin solution depends largely upon the amount of excess water over that soluble in the fatty material at the temperature and pressure selected which is introduced to wash out the glycerin and carry it through the apparatus.

The apparatus illustrated in Fig. 2 is operated in a similar manner, the fatty material being introduced above the settling zone 2! by means of The water meanwhile flows in the opposite direction from inlet 25, and the water being introduced below the settling zone I! by means of inlet ii. The water and fatty material thus pass through the apparatus in counter-current flow over a long path in intimate contact. The aqueous glycerin is removed from the bottom of the settling zone by means of outlet 24, and the fatty acids are removed from the top of the settling zone II by means of outlet 21, the hot outgoing materials then passing to suitable preheaters, such as shown in Fig. 5, where their contained heat is utilized for preheating fatty material. and water fed to the apparatus.

I have described the operation .as a continuous process, with water and fatty material continuously introduced into the apparatus in proper amounts, and proper proportions; and I prefer to operate the process in such continuous manmay be operated in an intermittent or semi-continuous manner, with intermittent or alternate introduction of water and fatty material, within the scope of'my invention in its broader aspects. Also, while I have described the invention as one involving the hydrolysis of fats and fatty oils by the use of liquid water alone, at high temperatures and pressures, it should be understood that if desired, andif unobjectionable, suitable catalysts may be used to speed up the hydrolysis.

Where in the following claims the expression "substantially above" is used, it is intended to limit such claims to exclude only those pressures which are insufllcient to maintain water in the liquid state at all times at the operating temperatures, and to include all other pressures,

while maintaining two liquid phases.

I claim:

l. The method of hydrolyzing fats and fatty oils which comprises intimately contacting such fatty material with water by countercurrent flow,

'at 'a temperature of above about 200 C. and at a pressure about 200 to 250 pounds in excess of the pressure of saturated steam at this temperature range whereby the fatty material will dissolve water in amounts substantially in excess of the amount required to hydrolyze the fatty material while maintaining two liquid phases, the water being used in amounts sufllcient .to supply that required for hydrolysis, that dissolved in the fatty material, and that required to wash out and remove the glycerin from the fatty material as aqueous glycerin.

2. The method of hydrolyzing fats and fatty oils which comprises intimately contacting such fatty material with water by countercurrent flow, at a temperature of above about 200 0., said water being maintained in liquid condition by a pressure substantially above the saturation pressure ofsteam at the highest temperature employed, whereby the fatty material will dissolve water in amounts substantially in excess of the amount required to hydrolyze the fatty material while maintaining two liquid phases, the water being used in amounts suflicient to supply that required for hydrolysis, that dissolved in the fatty material, and that required to wash out and remove the glycerin from the fatty material as aqueous glycerin. 1

3. The method of hydrolyzing cocoanut oil which comprises intimately contacting such co- 'ner. Nevertheless, the process and apparatus coanut oil with water by countercurrent flow, at a temperature of above about 200, C., said water being maintained in liquid condition by a pressure substantially above the saturation pressure of steam at the highest temperature employed, whereby the coacoanut oil will dissolve a greater quantity of water than that required to hydrolyze the cocoanut oil while maintaining two liquid phases, the water being used in amounts sumcient to supply that required for hydrolysis, that dissolved in the fatty material, and that required to wash out and remove the glycerin from the fatty material as aqueous glycerin.

4. The method of hydrolyzing tallow which comprises intimately contacting such tallow with water by countercurrent flow at a temperature of above about 200 (3., said water being main I glycerin which comprises countercurrently contactingfatty acid glycerides and liquid water under pressure at a temperature above about 200 C. but below that temperature at which the fatty materialand water form a single phase, the

quantity of water being sufllcient to hydrolyze the fatty acid glycerides and to remove the glycerin so formed, the pressure being sufficient to maintain the water in the liquid state at the operating temperatures.

6. The method of hydrolyzing fats and fatty oils which comprises contacting such fatty material with water by countercurrent flow, at a temperature above about 200 C. and sufficient to cause the fatty material to dissolve water in amounts required to hydrolyze it, said water be- 4 ing present in amounts suillcientto supply that required for hydrolysis, that dissolved in the fatty material} and that required to wash out and remove the glycerin from the fatty materialas aqueous glycerin, the water being maintained in liquid condition at all times by the application of pressure, the temperature and pressure being below that at which a single liquid phase is formed.

- MARTIN HILL

Images