IL30419A - Process and apparatus for the fractionation of fatty materials - Google Patents

Description

Process and apparatus for the fractionation of fatty materials RICHARD KASSABIAH C. 28692 This invention relates to a new and improved apparatus and process for the fractionation of triglyceride or fatty acid mixtures into respective, commercially valuable fractions thereof and, more particularly but by no means exclusively, to apparatus and process for the fractionation of palm oil to obtain therefrom a fraction which is eminently suitable for use as a commercial substitute for cocoa butter.

The prior art is, of course, replete with apparatus and processes for triglyceride oil and/or fatty acid mixture fractionations but, in most instances, each of the said prior art apparatus and processes are known to embody disadvantages when employed on commercial scale. More specifically, in some instances the said prior art apparatus and processes do not provide for sufficient fraction separation resolution, to thus render impractical the separation of closely related fractions or, alternatively, require the use of unduly large numbers of process stages to compensate for this lack of sufficient process resolution. In other instances, the said apparatus and processe of the prior art are far too complex and costly in fabrication, Operation, and. process material requirements for reasonable commercial application. In still other instances, the said apparatus and processes of the prior art are suitable for laboratory or pilot plant use but are inherently of such relatively small capacity as to be inapplicable to large scale commercial use . e n to provide new and improved process and apparatus for the fractionation of triglyceride and fatty acid mixtures with extremely high fraction resolution.

Another object of this invention is the provision of apparatus and process as above which are of particularly simple and economical design, construction and manner of operation and which require therein the use of only readily available compo- , nents of proven dependability, and of readily available process operating materials.

A further object of this invention is the provision of apparatus and process as above which are particularly adapted to economical, large-scale commercial use.

A still further object of this invention is the provision of apparatus and process as above which are particularly, though by no means exclusively, adapted to the fractionation from palm oil of a superior quality, eminently suitable commercial substitute for cocoa butter at a cost per unit weight of th latter far below currently prevailing costs of cocoa butter.

As disclosed in detail herein, the apparatus and process of my invention are directed toward the fractionation of a triglyceride into a plurality of the commercially valuable ' ' ■ ■ . fractions thereof. More specifically, multi-stage fractionation apparatus are provided which comprj.se, for each stage thereof, fractionation means in the nature of a "cold" room wherein are process of my invention, solvent supply tanks 12 and 14 will |! hold different solvents - for example acetone and isopropanol, respectively, as discussed in detail hereinbelow - whereby the readily adjustable pump means 19 and 20 may be adjusted to " provide a wide range of solvent blends, by volume, from the solvent supply tanks to the liquid metering means 22 and therefrom to a solvent blend delivery conduit 26 as should be obvious .

For use in the fractionation of triglyceride oils, oil supply tanks 28 and 29 are provided for the supply of triglyceride oils which, in some instances, have been neutralized t and washed in conventional manner, and are connected as shown by [i conduits 30 and 31 to readily adjustable pump means 32 of suit-' |j able performance characteristics. Non-illustrated temperature control means in the nature, for example, of cooling or heating coils are incorporated in each of oil supply tanks 28 and 29 to enable the maintenance of the oils contained therein at desired ■!'■ temperature levels and in the liquid state. Pump means 32 are in turn connected as shown to conduit 26 by conduit 34 extending the between, and readily adjustable liquid metering means 36 are connected as shown in conduit 34. In-line mixer means 33 are arranged as shown in delivery conduit 26 downstream of the I juncture thereof with conduit 34. Thus may be readily under- stood whereby proper adjustment of the respective pump means 20 and 32, and liquid metering means 22' and 36, will result in the delivery of a blend of miscella of the distinct solvents from oil supply tanks 28 and/or, 29 of desired volumetric proportions, to a point in conduit 26 just downstream of the juncture thereof " with conduit 34.

A miscella blend or make-up tank 38 is connected as shown to conduit 26 downstream of the said juncture, and is provided to insure proper blending of the solvent and triglycerid oil constituents of the said miscella prior to further utilization thereof. To this effect, the said make-up tank will preferably include non-illustrated agitator means to insure proper solvent-oil mixing and will, in addition, preferably include non-illustrated temperature control means to provide for the maintenance of the miscella at a desired temperature level .· . ■· . ■ A process feed tank 40 is connected to blend tank 38 by conduit 42, and readily adjustable pump means 44 are con- nected as shown in the latter. In the manner of tank 38, tank 40 also preferably includes non-illustrated agitator and temperature control means, respectively. The tank 40 is connected to the fractionation stage 10 by delivery conduit 46, and readily adjustable pump means 48 are connected in the latter to thus provide for the steady delivery of themiscella, at a desired rate, and at a desired temperature, to the said fractionation stage.

If desired, the process blending and feed stage 8 may outlet, conduit 70. An inlet conduit 72 may be utilized to connect tank 60 to any point in the fractionation stage 10 to thus provide for the storage of the miscella being processed in the event of fractionation stage failure. In like manner, outlet conduit 70 may be connected to any point in the fractionation stage 10 to provide for the re-introduction of the - thusly stored miscella thereto after the said failure has "been repaired .

Referring now to the. fractionation stage 10, the same |j may be seen to include a. plurality of adjacent "cold" rooms or sub-stages A, B, and C, respectively, formed as shown by heavily A wash solvent blend holding tank is indicated at 124 and is connected to pusher type centrifuge means 120A by condui 126A. The tank 124A functions to receive solvent blend from without the "cold" room A - as described hereinbelow - hold the said solvent blend for a period of time sufficient for it, to . assume the ambient temperature of "cold" room A, and introduce it, through conduit 126A, to pusher type centrifuge means 120A as a wash solvent blend to maintain a fraction in solution for purposes described in detail hereinbelow ...

Self-thinker type centrifuge means are indicated at 128A, and the inlet thereof is connected as shown to an outlet of the pusher type centrifuge means 120A by conduit 130A.

Although described in detail hereinbelow, it is considered well to note at this juncture that the separation of a triglyceride oil fraction from the miscella in "cold" room A is effected by the of the reduced temperature prevailing in the scraped surface crystallizer means 114A, the slurry mixing, cooling and holding tank 116A, and the respectiv centrifuge means 120A and 128A, due to the respective dispositions thereof in "cold" room A, and the action of the solvent blend on the triglyceride oil, both of which result in the crystallization of the particular fraction, commensurate with the said "cold" room temperature, .and resultant centrifugal separation of the thusly crystallized fraction from the still the crystallized fraction 'output of the pusher type centrifuge means 120A, and a crystallized fraction discharge means 134A extend as shown from the crystallized fraction outlet of the self- hinker centrifuge means 128A~ to the said "Moyno" type pump means . Thus the triglyceride oil fraction separated from the miscella through the operation of the respective centrifuge means 120A and 128A may be conveyed to the said "Moyno" type pump means .' The "Moyno" pump means extend as shown through cold room wall 88 to. discharge into a separated fraction holding tank 138A. Thus, the fraetton "separated from the triglyceride oil through the operation of the apparatus of "cold" room A, and any small quantity of solvent blend which may remain therewith, may be transferred to holding tank 138A for further processing. ¼ A miscella discharge conduit 140A extends as shown from self-thinker type centrifuge means 128A, through heavily insulated wall 82, to the' inlet of the scraped surface crystal- 1 lizer means 114B of "cold" room B. Thus the miscella, minus, of course, the triglyceride oil fraction separated therefrom through the operation of the elements of "cold" room A, may be conveyed to "cold" room B for the separation therefrom of another triglyceride oil fraction commensurate with the tempera- ture prevailing in "cold" room B. nd 112 are of substan- discharge conduit 140A of self-thinker type centrifuge means 128A extending, as described hereinabove, through cold room · wall 82 into connection with the inlet of scraped surface -crystallizer 114B, and miscella discharge conduit 140B of self-thinker type centrifuge means 128B similarly extending into connection with the inlet of scraped surface crystallizer 114C.

The "Moyno" type pump means 136B from "cold" room B extend as shown to fraction holding tank 138B, while the ilrMoyno" type pump means 136C from "cold" room C extend as shown to fraction holding tank 138C. · The miscella discharge conduit 140C from the self-thinker type centrifuge means 128C extends as shown to a pro-' cessed miscella holding tank 142.

Each of the separated fraction holding tanks 138A, 138B and 138C, and the processed miscella hold tank 142 is connected as shown, by conduits 144, 146, 148 and 150 to solvent stripper means 152 whereby the solvent blend remaining with the said separated fractions and processed miscella may be readily stripped therefrom. An evaporation means 143 is interposed in conduit 150 since a relatively large amount of solvent blend is present in the processed miscella from tank 142. Thus the evaporation means 143 will function to remove most of this solvent blend before the processed miscella is fed to the solven stripper means 152. Solvent blend return lines 154 and 155 accordance with the desired solvent blend proportions, the reconstituted solvent blend may, if desired, be supplied for solvent blend wash purposes, to the respective "cold" room, wash solvent blend holding tanks 124A, 124B and 124C.

Deodorizer means 158 are connected to solvent strippe means by conduit 156 and will, of course, function to deodorize the respective separated fractions prior to the transport thereof, as indicated by 160, to fraction collection means 162.

OPERATION In the utilization of the depicted fractionation apparatus of my invention for the fractionation of, for example, palm oil into a plurality of the fractions thereof, with particular emphasis being placed upon the economical production of a commercially acceptable substitute for cocoa butter, oil supply tanks 28 and 29 are filled with palm oil which has been neutralized and washed in conventional manner to insure that no soap is present therein. Similarly, solvent supply tank 12 is filled with acetone of commercially available grade, and solvent supply tank 14 isjrilled with isopropanol of 99% purity, again a commercially available grade, it being here emphasized that other and different solvents may find satisfactory utilization in this process as discussed in detail hereinbelow.

This filling of the respective oil and solvent supply tanks may be effected in any convenient manner, as for example operable tank filling means may be: employed to maintain a constant supply of palm oil and solvent to the said tanks and thus enable substantially continuous operation of the process. Alternatively, and since in practice the respective oil and solvent supply tanks would be of very large capacity, batch type filling thereof Could, of course, be employed.

Prior to the commencement of operation, each of pump means 19, 20 and 32, and liquid metering means 22 and 36 are adjusted to provide a solvent blend of approximately 257„ by weight of acetone and approximately 75% by weight of isopropanol, A commonly referred to as iiciso 2575 by those skilled in this art, to conduit 26, and a blend or miscella of approximately 50% by weight of neutralized palm oil and 50%, by weight of the said solvent blend, to miscella make-up tank 38 and, as follows, process feed tank 40, It is here again emphasized, however, that other and different solvent blends may be satisfactorily utilized and that as a general range for the fractionation of palm oil using acetone and isopropanol, solvent blends ranging from 5% to 50% by weight of acetone and 95% to 50% by weight of isopropanol may be used.

In addition, and with aciso 2575 as the solvent blend, heat exchanger means 92, ,94, and 96 are regulated by the non-illustrated control means associated therewith to provide and maintain temperatures of approximately 75°F in cold room A, 60°F in cold room B, and 50°F in cold room C. In this re ard determined to lesult in very desirable crystallization characteristics, at the respective, relatively high sub-stage temperatures referred to hereinabove, within the respective fractionation apparatus 112A, 112B and 112C; it being noted that the isopropanol app~eaTs~~~td^function primarily as an acetone diluent in that the use of a significantly larger proportion of acetone would require a lower temperature for the respective sub-stage crystallizations, and especially insofar as the crystallizations of the lower melting point di-unsaturated and/or tri-unsaturated triglycerides are concerned.

This is to say that the diluted solvent power of the acetone (as reduced by the' isopropanol addition) causes the respective fatty fractions to be on the verge of precipitation whereby the latter can be selectively separated by the relatively slight, e.g. approximately 15°F, changes in temperature occurring between the respective "cold" rooms A, B and C. Thus, although the isopropanol is normally considered a solvent, it may, in this instance, be referred to as a diluent. Of addi-tional significance is the fact that, since the respective fatty fractions are on the verge of precipitation, the relatively moderate "cold" room temperatures of crystallization can be employed as compared, for example, with the much lower tempera-. ;' ; ' tures of crystallization required .by . the somewhat similar processes of the prior art, whereby the significant economics of respective pusher-type centrifuge means 126A, 126B and 126C, so that the amount of oil removed, in crystallized fraction . form from each "cold" room, would be replenished by an approximately equal amount of wash solvent blend. Further, the addition of wash solvent blend as described above would insure that fractions which are not to crystallize in any particular "cold" room will remain substantially in solution and pass therethrough for crystallization in a succeeding cold room, or removal with the processed miscella through conduit 140C from "cold" room C.

In this latter regard it is noted that palm oil contains a relatively small, but very valuable beta carotene fraction, and that the addition of the wash solvent blend will function to retain this carotene fraction in solution for discharge with the processed miscella whereby the latter may, if desired, be further processed through the use of a similar solvent fractionation process to further concentrate the said carotene fraction to significant economic advantage.

Once steady state operational conditions have been reached, operation of the depicted apparatus would thus entail the flow to and through the respective miscella make-up tank 38 and process feed tank 40 of approximately two tons per hour of the miscella with the said tanks functioning to both insure satisfactory mixing of the solvent and oil to form the miscella, and the maintenance of the latter 'at a temperature above that at which crystallization of the first triglyceride fraction will exchange unit which takes the form of the jacketed, scraped surface crystallizer 114A of "cold" room A, it will rapidly assume the 75° temperature of the said jacketed crystallizer whereby crystallization of the first fraction hereinafter referred to as Si will begin. Accordingly, the scraping action of crystallizer 114A will insure that these crystals which do form will be continuously scraped from the walls thereof for re-introduction to the miscella slurry so as not to interfere with the occurrence of the desired miscella-jacket heat exchange relationship.

The resultant crystal-miscella slurry is then flowed to slurry mixing and cooling tank 116A wherein it is retained for a period of time sufficient to promote further crystal growth. In instances wherein a three hour "cold" room retention time is utilized, the period of retention in the tank 116A might approximate 2.8 hours.

Flow of the slurry from cooling tank 116A to pusher-type centrifuge means 120A is then effected whereby the latter will function, through conventional centrifuge operation, to remove the crystallized fraction Si from the miscella or mother liquor and deliver the former to the rtMoyno" type pump means 136A. The addition of the wash solvent blend to the centrifuge means 120A will enable the washing.of. the S-^ fraction crystals in additional solvent blend to insure the removal of substantially operate to remove any remaining, minor quantities of fraction crystals from the miscella and effect the delivery thereof to "Moyno" type pump means 136A through delivery conduit 134A. Thi makes clear whereby the combined action of the respective centri fuge means 120A and 128A, and the introduction of wash solvent blend, will insure a substantially complete removal of the crystallized S-^ fraction from the miscella and delivery of the former to the pump means 136A. As a result, the crystallized Si fraction will be supplied from "cold" room A, through "Moyno" type pump 136A, to the holding, tank 138A, while the misc'ella or mother liquor, including the additional solvent blend introduced thereto from wash solvent blend holding tank 124A, will be supplied, through conduit 140A, to the inlet of the scraped surface crystallizer 114B of "cold" room B.

Operation of the fractionation stage 112B in "cold" room B and of fractionation stage 112C in "cold" room C will be substantially as described hereinabove for fractionation stage 112A in "cold" room A. Thus fractionation stage 112B will function to crystallize, at approximately 60°F, and separate from the miscella a second fraction, hereinafter referred to as and discharge the same through "Moyno" type pump means 136B to S'2 holding tank 138B, while fractionation stage 112C will function to crystallize, at approximately 50°F, and separate f om the miscella a third fraction; hereinaf er referred to as S3 and discharge the same through "Moyno" type pump means I36C to 1- S2> 53, and S4 fractions are delivered by conduit 160 to fraction collection means, as indicated at 162 , which may take any form convenient to. the collection and packaging of the said fractions.

Preferably the fraction collection means 162 will include flaking drum means to put the respective fractions S-^, and S3 in flake form for. final collection and packaging, it being understood that the fraction will be in liquid form at the ambient fraction collection point temperatures.

In practice, this solvent stripping, deodorization and fraction flaking and collection will be accomplished sequentially v Thus, and through the use of non-illustrated valjde or similar flow control means in each of conduits 144 , 146 , 148 and 150 , the system may be arranged, for example, to first deodorize and f deliver for collection fraction S-j_, then fraction then fraction S3 and finally fraction S^.

For convenience of description, the composition of the miscella at the entrance and exit thereof from each of the fractionation stages 112A, 112B and 112C , and various significant chemical and physical properties of the respective, separated palm oil fractions and residual miscella, are listed directly hereinbelow in TABLE A.

TABLE A Exit Process Exit Fra Feed Stage 8 Stage 11 Fraction From Each Stage - Sl r Refractive Index - - Approximate Triglyceride Comp. - GS3 !! :| ;. The fraction is essentially a tri-saturated !}. fraction and is suitable for all applications wherein hydro- 1. genated flakes and saturated fats of similar nature are il utilized. A distinct advantage of the S]_ fraction resides in i the fact that it has not been hydrogenated and would thus not , contain any isomerized chains as are normally found in hydrogenated fats. As a~result, the S]_ fraction will have a lower melting point than tri-saturated triglycerides containing isomerized fatty acids and will be particularly useful, for ex- i ample, as a binder in peanut butter and/or halvah to prevent ■ oil separation, and in candy coatings. This is to say that ' the Si fraction can satisfactorily perform the functions of hydrogenated oils without giving rise to the elevated melting i, ■ j. · . · . , · ■ j: points encountered with isomerized oils. Fuller discussion . of this advantage of the fraction may be found on page 540A, September Meeting Report of the J. Am. Oil Chemists Soc, Vol.

The S and fractions are each, as discussed hereinabove, eminently suited for large, scale commercial use as substitutes for cocoa butter at prices well below the current prices for the latter. This eminent suitability of the S and S3 fractions as cocoa butter substitutes, and further information on the chemical properties of the S^, S4 and CL fractions for the respective uses thereof discussed above, are believed clearly illustrated by the following REPORT OF ANALYSIS I which presents the results of chemical analyses conducted by a highly qualified, independent chemistry laboratory at my request on my samples of the. fractions S]_, S2» S3, S4, CL as produced in accordance with the process~6f my invention as disclosed herein, and two samples of cocoa butter of commercially available grade. Also presented are the AOCS values for cocoa butter.

The marked similarity in purely physical properties - which are, of course, of great significance insofar a the feasibility of the commercial utilization of the S and S3 fractions as substitutes for cocoa butter in applications such as the making . of chocolate is concerned - between S2 and S3, and cocoa butter, are believed clearly illustrated by the following REPORT OF ANALYSIS II which presents the results of dilatometric analyses conducted by the same laboratory and under the same circumstances as described hereinabove with regard to REPORT OF ANALYSIS I.

REPORT OF ANALYSIS II Cocoa Sample Identification ^2 S^ Butter Solid Fat Index AOCS (Cd 10-57 at 10.0°C ' 53.5 , 58.8 66.9 21.1°C 43.8 47.0 53.9 26.7°C 29.4 26.9 16.1 33.3°C 0 0 0 37.8°C 0 0 0 40.0°C s. 0 0 0 Of. particular significance here is the fact that each of the S2 and S3 fractions change completely to a liquid, as indicated by the 0 value for the solid fat index - the percent of solids in the fat - in the same narrow temperature range as does commerciall available cocoa butter. Thus is assured that tion. It is therefore desired that the protection afforded b Letters Patent be limited only by the true scope of the appended claims -28- 30419/2 t *

Claims (13)

1. CLAIMS la A process for the separation of one or more fractions from a fatty material in the nature of a fat or fatty acid, wherein the fatty material is mixed with a blend of acetone, or of methyl ethyl ketone, with a lower aliphatic alcohol in which blend the alcoho}. is solvent a diluent for the ketone, to form a fatty materialTbland miscell j the miseella is held at the crystallization temperature of the fraction to be crystallized from the miscella, and the fraction thus crystallized is removed from the miscella, and If two o more fractions are to be separated, the operation Is repeated at the crystallization temperature of each fraction concerned,..

2. · A process according to Claim 1, wherein the fatty material and the blend are mixed in proportions ranging from It2 to 2:1 parts by weight·

3. A process according to Claims 1 or 2, wherein the lower aliphatic alcohol is ethanol, isopropanol or butanol.

4. A process according to Claims 1, 2 or 3, wherein the blend of acetone or methyl ethyl ketone with the lower aliphatic alcohol contains these ingredients in a rati© from 1:19 to 1:1 parts by weight, preferably in a ratio of about 1:3·

5. A process according to any of Claims 1 to 4, wherein the blend consists of acetone and isopropanol, preferably of about 25$ by weight of acetone and about 75$ by weight of Isopropanol.

6. · A process according to any of Claims 1 to 5, wherein the fatty material is palm oil and the separation is carried out in three stages in which the miscella ie first held at from 70°F to 80°F, preferably about 75°F, to crystallize a first fraction and this is removedj then the residual miscella from the first stage is held at a temperature from 55°F to 65°i\ preferably about 60GP., to crystallize a second fraction and this is removed; then the residual miscella from the second stage is held at a temperature from 45°!' to *>5°F» preferably o t 50°P, to crystallize a third fraction and this is removed from the residual miscella which contains a fourth fraction of the palm oil and the blend.

7. · Cocoa butter substitutes being constituted by, or comprising, the second and/or third crystallized fractions produced by the process according to Claim 6.

8. · A process according to Claim 1, for the separation of one or more fractions from a fatty material in the nature of a fat or f tty acid, substantially as described herein.

9. · An apparatus for carrying out the process according to Claim 1, comprising at least one fractionation unit including a heat-insulated chamber and temperature control and heat exchange means for maintaining in the chamber a temperature suitable for the crystallization of the fraction to be separated; a first crystallize designed to receive the miscella, to lox*er its temperature to that prevailing in the c .Id chamber and to start crystallization of the desired fraction; a second crystallizer designed to receive the slurry of crystals and miscella from the first crystallizer and to allow the crystallization to be completed at the temperature of the rotary vacuum filter cold chamber; and at least one -cetitri-fttge-for separating the crystals from the miscella.

10. An apparatus according to Claim 9» wherein the first crystallizer is a scraped-surface crystallizer and the second crystallizer is a holding tank provided with a stirrer of a volume such as to permit retention of the slurry until the crystallization 30419/2 - 30 -

11. · An apparatus according to. Claim 9» comprising two centrifuges mounted in series and a wash solvent blend tank provided with cooling means tojceep the solvent blend used &r rotary vacuum filter washing the crystals in the first ee»-3*i-f-»ge- at the temperature of the cold chamber,

12. An apparatus according to any of Claims 9 to 11, comprising three series-connected fractionation units for carrying out the process of Claim 6.

13. An apparatus for carrying out the process aocording to Claim 1, substantially as described herein with reference to the accompanying drawing. For the Applicants DR.REINHOLD COM/A D .PARTNERS ¾y: PC:BH