THESE» ' . "W‘Mww‘x L§@“£Yl Michigan 3mm f *1“ Univemity ‘ 335;. 5“.- . t rt \ "i This is to certify that the dissertation entitled PROCESS ANALYSIS OF THE AQUEOUS FRACTIONATION 0F TALLOW presented by David Allen Glassner has been accepted towards fulfillment of the requirements for M~4degree in ~SILELLIIJLcsaLEngi neeri ng Major professor Eric A. Grulke Date 11-16-83 MSU i: an Affirmatiw Action/Equal Opportunity Institution 0v 1 2771 NVISSI_J RETURNING MATERIALS: Place in book drop to lJBRAflJEs remove this checkout from “ your record. FINES will be charged if book is returned after the date stamped below. PROCESS ANALYSIS OF THE AQUEOUS FRACTIONATION OF TALLOW By David Allen Glassner A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Chemical Engineering 1983 ABSTRACT PROCESS ANALYSIS OF THE AQUEOUS FRACTIONATION OF TALLOW By David Allen Glassner Fractionation of tallow can produce fractions of tallow having more value than the original tallow. The aqueous fractionation of tallow involves diSpersing an aqueous solution, containing a surfactant and an electrolyte, in a partially crystallized tallow. The diSpersion is centrifuged to yield the product fractions. Two fractionation procedures were examined. .The formation of the crystals and the aqueous diSpersion were found to be the most important steps of the process. The rate of cooling and shear applied during crystallization controlled the crystal size achieved. Small crystal size, less than ten microns, caused the formation of emulsified olein. A crystal size of 100 microns produced the greatest olein yield when 0.6 to 1.0 % sodium dodecyl sulphate (by weight of the tallow) was added. Increasing the sodium dodecyl sulphate concentration above 1.3 % resulted in the formation of emulsified olein. The optimum sodium citrate (electrolyte) concentration was found to be 5.0 % based on the solution weight. ACKNOWLEDGEMENTS I express my thanks to Dr. Eric A. Grulke for his guidance in this project. I thank Dr. J. Ian Gray for the use of his laboratory facilities and his support for the project. I also thank Dr. James Pestka for the use of his laboratory facilities. ii TABLE OF CONTENTS LIST OF TABLES. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I iv LIST OF FIGURES. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I v NOMMCI‘ATURE. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Vi INTRODUCTION. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1 LITERATURE REVIEW. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 5 Chemist” I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0000000 I ...... 5 Fractionation Tecmiques I I I I I I I I I I I I I I I I I I I I I I I I I I I I 8 Aqueous Fractionation I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 9 Crystallization I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ll Aqueous Dispersion.IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 12 centrifugationICCCCIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 13 EXPERIMENTAL METHODS 16 Nonscalable Fractionations.......................... 16 scalable FractionationIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 23 Characterization of Fractions....................... 28 Photomicroscopy..................... ...... .......... 30 RESULIE AND DISCUSSIONIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 31 Partial crystallizationIIIIIIIIIIIIIIIIIIIIIIIIIIIII 31 sufiactant AdditionIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 33 Aqueous DisperSionIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 38 mulSified OleinI.IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 38 Surfactant and Electrolyte Concentration Tests...... 42 Scalable Experimental Results....................... 52 Fatty Acid Analysis..................... ..... ....... 53 CONCLUSIONSIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIfi APPEINDIXI -PROCESS FIDWCI'IARTO0.0000000000000000coco... 59 APPENDIX II - MIXING POWER CAI’CIIIATIONSIIIIIIIIIIIIIIIIII 70 APPENDIX III - FRACTIONATION AND FATTY ACID ANALYSIS DATA 72 LITERATURE CITED...IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 79 iii 11. 12. 13. 14. 15. 16. 17. LIST OF TABLES TALLOW FATTY ACID COMPOSITIONS......................... 6 DESCRIPTION OF FRACTIONATION PROCEDURES................ 17 SOURCE OF MATERIAIS.................................... 18 COMPARISON OF SCALABLE AND NONSCALABLE PROCEDURES...... 22 TURBINE CHARACTERISTIC MEASUREMENTS.................... 25 SATURATED AND UNSATURATED FATTY ACID COMPOSITIONS OF TALIIOW AND FRACTIONS OF TALIDW00000000000000.0000.so... 57 FATTY ACID COMPOSITION OF TALLow AND FRACTIONS ..-..-... 57 memmsmmmmmmuAMEmmymumm.nunu.& FLOWCHART EQUIPMENT DESCRIPTION........................ 64 EN’IHALPIES OF FRACTIONS 69 POWER REQUIRED FOR THE AQUEOUS DISPERSION.............. 71 DRY FRACTIONATION DATA 73 SURFACTANT CONCENTRATION FRACTIONATION DATA............ 74 ELECTROLYTE CONCENTRATION FRACTIONATION DATA .......... 75 ACTUAL AND NORMALIZED FATTY ACID COMPOSITIONS: RUN 3... 76 ACTUAL AND NORMALIZED FATTY ACID COMPOSITIONS: RUN 4... 77 SATURATED VERSUS UNSATURATED FATTY ACID DATA........... 78 iv 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. LIST OF FIGURES FLOW DIAGRAM FOR THE AQUEOUS FRACTIONATION OF TALLOW. . . NONSCALABLE BATCH FRACTIONATION EQUIPMENT ...... . . . . . . .. SCALABLE BATCH FRACTIONATION VESSEL. . . .. . . .. . . . . . . . . . . . PARTIALLY CRYSTALLIZED TALLOW (100x MAGNIFICATION)..... PARTIALLY CRYSTALLIZED TALIOW (450x MAGNIFICATION)..... OLEIN YIELD VERSUS RELATIVE CENTRIFUGAL FORCE. . . PARTIALLY CRYSTALLIZED TALIOW WITH SDS (450x MAGNIFICATION).OOOOOOOOOOOOOOOOOO0000000 INITIAL AQUEOUS DISPERSION (100x MAGNIFICATION)..... . . . AQUEOUS DISPERSION READY FOR CENTRIFUGATION (100x MAGNIFICATION).......................... EMULSIFIED OIL BORDER (450x MAGNIFICATION)... . . . . . .. CENTRIFUGATION TUBES WITH FRACTIONATION PRODUCTS. EMULSIFIED OLEIN (100x MAGNIFICATION).................. OLEIN YIELD VS. PERCENTAGE SDS: HUN 1 OLEIN YIELD VS. PERCENTAGE SDS: RUN 2 OLEIN YIELD VS. PERCENTAGE SDS: RUN 3 OLEIN YIELD VS. % ELECTROLYTE: RUN 1+ % UNSATURATED ACIDS VS. 7. SDS 95 UNSATURATED ACIDS VS. % ELECTROLYTE.................. PROPOSED PROCESS PRODUCTS AND FRACTIONATION SCHEME“ PRELIMINARY TALDOW AQUEOUS FRACTIONATION FLOW DIAGRAM. . TALIDW mTI-IAIJPY DIAGRAM.O0.0000000000000000...000...... 21 24 32 3A 35 36 39 no 41 ’43 51 55 6O 61 68 VARIABLE Bram RCF rpm SDS 129 NOMENCLATURE DEFINITION Applied Gravitational Force (normal) Sedimentation Value Sedimentation Path Length (inches) Diameter of a Sphere Relative Centrifugal Force Maximum Rotor Radius (inches) Revolutions Per Minute Sodium Dodecyl Sulphate Time (minutes) Fluid Density Speed of Fluid Past a Solid Liquid Viscosity vi INTRODUCTION Edible tallow is the fat rendered from cattle during the processing of beef. It is a complex mixture of triglycerides which are formed when carboxylic or fatty acids are esterified to glycerol. The fatty acids can be unsaturated or saturated. In tallow, oleic acid is the predominant unsaturated fatty acid and stearic and palmitic acids are the main saturated fatty acids. Unsaturated fatty acids have much lower melting points than saturated acids. Oleic acid melts at 14°C whereas stearic acid melts at 69.6OC (Swern et a1, 1979). The same effect on the melting point of triglycerides containing these acids is observed. When fractionated, the low melting fraction is called the olein and the high melting fraction is called the stearin. Large quantities of tallow are produced in the United States. In 1973, 5.5 billion pounds of tallow was produced in the United States. Only 500 million pounds was used for edible purposes (Kromer and Gazelle, 1974). About 1.8 billion pounds of fats and oils such as cocoa butter, coconut oil, palm oil, and palm kernel Oil were imported in 1973 (Kromer, 1974). Meanwhile, about half the tallow produced in the United States is exported (Taylor et a1, 1976). Tallow has been selling for less than 20¢ per pound, while cocoa butter has varied between 50¢ and $1.50 for the last ten years (Taylor, et a1 1976). Cocoa butter contains essentially the same fatty acids as l 2 tallow contains. If tallow or part of tallow could be altered to imitate the properties of an expensive imported fat or oil, an economic gain could be made. Fractionation is the process of Splitting a fat or oil into two parts with dissimilar preperties. Tallow frac- tionation can provide a fraction of tallow which closely resembles cocoa butter (Luddy et a1, 1973). Dry, solvent and aqueous are the known methods of fractionation. The best of these fractionation methods is the aqueous frac- tionation method (Braae, 1976). The aqueous fractionation is better than the dry fractionation method because the olein yield is higher and the process is less labor intensive. The olein is the more valuable fraction in the case of tallow, and can be used for salad oil. The solvent fractionation method has the disadvantages of a complicated solvent recovery and explosion proof design costs. Aqueous fractionation involves three key steps: a frac- tional or partial crystallization, an aqueous diSpersion and a centrifugation of the diSpersion, as shown in Figure l. The whole tallow is partially crystallized at the fractionation temperature. This temperature is picked to give the fractions desired properties. After the partial crystallization, an aqueous solution containing a surfactant and an electrolyte is added and an oil-in-water diSpersion is formed. The aqueous solution content varies depending on the process used. Centrifugation follows yielding an olein product and an TALLOW PARTIAL STORAGE C RYSTALLI 2 E R OLEIN AQUEOUS DISPERSION CENTRIFUGATION STEARIN RECYCLE Figure 1. FLOW DIAGRAM FOR THE AQUEOUS FRACTIONATION OF TALLOW. 4 aqueous stream containing the stearin. This stream is heated_ and centrifuged again yielding the stearin product and the aqueous solution. Three aqueous fractionation procedures have been dis- cussed in recent literature. Haraldsson (1974), Rek (1977) and Bussey, et al., (1981) have used three different aqueous fractionation techniques. Bussey, et al. are interested in the cholesterol distribution in the fractions, the quality of food prepared with the fractionation products and the dis- tribution of key flavor precursors. The engineering concerns of the fractionation technique of Bussey, et al. have not been studied. The goal of this research is to develop a funda- mental understanding of the process steps, develop a process flowchart and identify any problem areas. Of particular concern to this research was the pro- duction of a uniform product and a consistent yield of product. This concern extended to different batches of tallow as well as identical samples. Factors affecting the yield and uniformity of the product were closely examined. The partial crystallization and the diSpersion processes were given the most attention. The effect of agitation on crystal formation was seen. The disPersion process was studied using various concentrations of the surfactant and the elec- trolyte. The centrifugation step was examined for separation efficiency and maintenance of product quality. LITERATURE REVIEW A review of the literature pertinent to the aqueous fractionation of tallow begins with a review of triglyceride chemistry. A discussion of the different fractionation techniques follows. The fractionation technique of interest, aqueous fractionation is reviewed next. The individual steps of the aqueous fractionation procedure are reviewed last. CHEMISTRY Tallow, like all fats and oils, has a complex chemistry. This is because many fatty acids exist which can fill the three glycerol positions stereospecifically. Fatty acids can alter a property of a fat by changing the glycerol positions each occupies. The fatty acids present and the positioning of these fatty acids distinguish one fat from other fats. The fatty acid composition of a fat is not invariant. Table 1 shows three fatty acid compositions reported for tallow. The variations shown in Table 1 cause slight dif- ferences in properties like melting point and iodine value but will cause a large change in crystallization properties at a Specific temperature. The differences between these samples in fatty acid composition can cause major differences in partial crystallization yields at a given temperature. 5 Table 1. IAIIOW FATTY ACID COMPOSITION Source of Data (2) (3) (4) Fatty Acid Common 1 Mole Common Name Shorthand Fractions Myristic acid 014:0 .044 .020 .036 Myristoleic acid Cl4:l .016 --- .014 Palmitic acid Cl6:0 .267 .350 .241 Palmitoleic acid C16:1 .050 '-—- .066 Stearic acid Cl8:0 .139 .160 .137 Oleic acid Cl8:l .417 .440 .501 Linoleic acid Cl8:2 .023 .020 ‘-—- Linolenic acid Cl8:3 .003 .004 .004 1 C16:1 means there are 16 carbons in the fatty acid chain with one unsaturation. 2 Luddy,et a1. , 1973. 3 Drew, Inc. 4 Bussey, et al., 1981. 7 Individual triglycerides can vary widely in melting point temperature even when they are part of the same fat. The reason for the melting point differences is that the fatty acids making up the triglycerides can be saturated or unsaturated. Trisatu— rated triglycerides solidify 60 to 70°C higher than triun- saturated triglycerides. In an actual fat or oil, the dif- ference is much less because the triglycerides have ran- domly distributed fatty acids and because of mutual solu- bility effects. Mutual solubility is illustrated by melting triolein and tristearin together at a high temperature. If the mixture is then cooled the tristearin will not recrystallize until the melting point of the triolein is almost reached, de- pending on the concentration of the two triglycerides. It is similar to a binary melting point depression but, with the hundreds of triglycerides in tallow, the effect is complex. The different melting points of triglycerides are the basis for fractionating a fat. A more valuable fat like cocoa butter has a narrow melting range of triglycerides. A fat like tallow can be fractionated to yield several fractions, each with a different melting range. The fractions produced imitate fats like cocoa butter if suitable frac- tionation temperatures were used. FRACTIONATION TECHNIQUES A fractionation begins by partially crystallizing the fat being fractionated, at a Specific temperature. The fat is held at the crystallization temperature long enough for equilibrium or a near equilibrium to form between crystallizing and noncrystallizing triglycerides to occur. Once the partial crystallization is complete, the fractionation is completed by making the liquid-solid separation. The object of any fractionation technique is to separate the liquid and solid portions efficiently. The Oldest technique is called winterization because it allows the olein fraction to remain a liquid at low temperatures. It is practiced on many fats including tallow. Originally, cool winter temperature was used to crystallize the Oils. These crystallizations were slow because of the gradual cooling caused by seasonal change. Large crystals resulted and crude skimming or filtering processes were used to separate the liquid and solid. A winterization technique was adopted for the first large scale fractionations. Crystallization times of 3 to 4 days are used to retard nucleation and allow large crystals to grow. Large crystals are necessary to allow filtering of the crystals from the oil. A plate type press with canvas cloths is used in this technique (Braae, 1976). Yields of 55 % are reported for this process for fats yielding 75 % by the aqueous fractionation technique (Braae, 1976). 9 A modern version of the dry fractionation method is called the Tirtiaux fractionation. Directed crystallization on a suitable fat is followed by filtration. A continuous vacuum filter equipped with a stainless steel perforated belt as a filtration support is used. Yields of 70 % olein are achieved when fractionating tallow at a temperature where aqueous fractionation would yield 80 % (Tirtiaux, 1983). Solvent fractionation is another type of fractionation. A large excess of a solvent like acetone is used to dissolve a fat completely. The solution is then brought to the cry- stallization temperature and held at that temperature to allow partial crystallization to occur. The solvent serves to reduce the liquid phase viscosity. With the reduced viscosity, filtration of the liquid solution from the solid crystals is easily accomplished (Luddy, et al., 1973). .The main drawbacks of the solvent fractionation system are that it must be explosion proof and solvent recovery is costly (Braae, 1976). Because of these drawbacks, the third fractionation system to be considered is advantageous when compared to the solvent fractionation system. AQUEOUS FRACTIONATION The aqueous system of fractionation was described and patented in 1905 by Fratelli Lanza. Industrially, the process has been used for 19 years by Alfa-Laval. The process described by Haraldsson (1974) is the process used by Alfa- Laval to fractionate tallow and palm oil. 10 The first of three aqueous fractionation procedures is that of Haraldsson (1974). The oil is cooled to partially crystallize it in large scraped wall vessels. An aqueous solution containing sodium dodecyl sulphate and magnesium or sodium sulphate is added to the partially crystallized oil. The partially crystallized oil and the aqueous solution are mixed. The aqueous solution becomes the continuous phase and captures the stearin. The dispersion is now fed to a centri- fugal separator. The olein is less dense than the aqueous- stearin mixture. Under centrifugal force the olein separates from the aqueous- stearin mixture. The stearin is recovered by heating the aqueous mixture, which.melts the stearin, and centrifuging to yield liquid stearin and aqueous solution to be recycled. Another aqueous fractionation technique was patented by Rek (1977). The patent claims to have improved the aqueous fractionation process by using an Oil soluble surface active agent, particularly an unsaturated C 8 (meaning 12 to 28 12-2 carbon atoms in the carbon chain of the acid) salt of a monoglyceride, i.e., potassium oleate. The soap is preferably solubilized in the triglycerides before cooling of the oil begins. The rest of the process is the same as Haraldsson's (1974). Rek claims better olein yields SSpecially at low temperature fractionations. The third aqueous fractionation technique is that of Bussey, et al., (1981). It claims to increase olein yield by ll adding the water soluble surface active agent directly to the partially crystallized fat. The tallow is brought from storage at 4°C to the fractionation temperature and softened before adding the surface active agent, sodium dodecyl sulphate. The surfactant is mixed with the softened tallow which is allowed to come to equilibrium for 18 hours. The aqueous solution containing only an electrolyte is added and diSpersed. Centrifugation procedures follow the formation of the dis- persion. Although the general methods are indicated, engineering details for the process remain unknown. The engineering details are mixing requirements during the crystallization and the aqueous diSpersion, surfactant and electrolyte requirements and centrifugal force needed. Rek and Haraldsson both represent industrial concerns who are unwilling to publish their process Specifics. Bussey, et al., (1981) described a process which they conducted on a laboratory bench scale. Therefore the knowledge about the engineering of the steps is limited. CRYSTALLIZATION The kinetics of crystallization for any fat are difficult to define. A major part of this difficulty is due to the large number of triglycerides present in a fat. The multitude of triglyceride Species gives rise to mutual solubility effects, which cause changes in the crystallization temperature for a single species because of the heterogeneous system. Therefore a priori calculation of crystallization temperatures is not 12 now possible even when the triglyceride composition is cal- culated. Crystallization depends on two factors: nucleation of crystals and the crystal growth rate. Nucleation can often be induced by agitation, mechanical shock, friction and extreme pressure. Most agitated solutions nucleate Spon- taneously at lower degrees of supercooling than nonagitated solutions. An increase in the intensity of agitation does not always increase nucleation rates. The crystal growth rate is usually proportional to crystal size (Mullin, 1972). Kinetic data for the crystallization of tallow can not be found in published literature. A necessary condition for aqueous fractionation is the formation of the proper type of crystals. If the prOper type of crystals are not formed, wetting will not occur. The size of the crystals is of minor importance. If the oil is cooled too rapidly, amorphous and unstable crystals are formed which are not wetted by the aqueous solution (Haraldsson, 1974). Some other literature suggests that crystals above a size of 10 to 25 microns are large enough for the aqueous fractionation procedure to be successful (Alfa-Laval). AQUEOUS DISPERSION After the partial crystallization step, the aqueous solution must be diSpersed into the partially crystallized tallow. The surfactant probably adheres to the solid surface so that it can be wetted by the aqueous solution. The elec- trolyte apparently helps to Spread the surfactant evenly. 13 Haraldsson (1974) does not reveal the chemical concen- trations required by the process. Rek (1977) Specifies the amount of oil soluble surface active agent or soap to be above 0.6 % (by weight of the oil) to the solubility limit of 2.0 % depending on the oil. The amount of water soluble surface active agent should be above 0.3 % (by weight of the fat) although the amount used in Rek‘s experiments was not constant. The electrolyte level was preferably 2.5 to 5.0 weight percent in the aqueous solution. The volume ratio Of aqueous solution to the fat is in an optimum range between 0.2:1.0 to 0.8:l.0. Bussey, et al., (1981) Specified the amount of water soluble surface active agent to be 0.6 % by weight of tallow. The electrolyte concentration is Specified to be 4.0 % by weight of aqueous solution. The amount of water is to be 60 % of the volume of fat fractionated. Comparison of chemical levels to olein yields are Sparse and not clear. Even less clear is how to form the aqueous dispersion through mixing. Rek (1977) and Bussey, et al., (1981) give no Specific mixing requirements. Haraldsson (1974) specified two stages of mixing. The first is an intense knife mixer and the second is a gentle paddle mixer where a form of coalescence occurs. CENTRIFUCATION Quantitative measurement of centrifugation is detailed in a DuPont Sorvall (1973) operating manual. The Speed of a l4 centrifuge is generally Spoken of in terms of revolutions per minute, rpm, but this is not the measurement of prime importance. Relative centrifugal force, RCF, is the proper term to use for representing the force applied. RCF denotes the strength of the gravity field to which a sample is subjected and is calculated by a combination of rpm and rotor radius. Any data indicating only an rpm Speed is not suf- ficient to enable duplication. The rotor radius and/Or carrier used must be identified. RCF is determined as shown in equation (1). RCF: (28.37)(rotor radius in inches)(rpm/1000)2. (l) The force on a sphere flowing very slowly through a liquid is described by Stokes Law. Equation (2) shows how to calculate the force (Bird, Stewart and Lightfoot, 1960). F a: 4/3 Tr R3’o g + 2r Rv,+4n;uRvm. (2) The first term on the right hand side of equation (2) re- presents the buoyant force on the particle. The second and third terms are the form drag and friction drag terms, reSpectively. The force on a Sphere being centrifuged could be calculated by replacing g in the buoyant force term by the relative centrifugal force. The time of centrifugation is also important. The sedimentation of a particle in a solution is dependent upon RCF, time, maximum radius and path length. For equal degrees of sedimentation equation (3) should be kept constant. = (RCFXTXZ x Rm-L)/(Rm x L)- (3) 15 Specification of the RCF, rotor type and time of cen- trifugation is sufficient to fully desribe centrifugation. None of the processes Specified these variables. EXPERIMENTAIVMETHODS The experimentation conducted for determining engineering parameters for the aqueous fractionation of tallow can be divided into two main categories: scalable and nonscalable batch fractionations. Scalable means that all significant geometries of crystallization and mixing were reproducible on a different scale. Nonscalable means that many parameters of the experiments were not reproducible. This did not mean that the results were not reproducible. It means that exact geometric and mixing parameters can not always be reproduced. Photomicroscopy experiments and fatty acid analysis methods are also to be discussed. The apparatus used for the scalable and nonscalable fractionations was developed in this laboratory. A fractiona- tion procedure referenced to an author means that the sequence of chemical additions was the same as the author's. A reference to an author does not mean their crystallization process, chemical concentrations, agitation or centrifugation procedures were followed exactly. Table 2 summarizes the procedures a reference to an author includes. Table 3 shows the source of materials used for experimentation. NONSCALABLE FRACTIONATION The nonscalable batch fractionations have some defining characteristics. Agitation was not used during the partial l6 17 Table 2. DESCRIPTION OF FRACTIONATION PROCEDURES. Haraldsson (1974) l. The tallow is partially crystallized from the melt. 2. The aqueous solution containing a surfactant and an electrolyte is added. 3. The aqueous dispersion is formed. 4. The aqueous diSpersion is centrifuged. Bussey,et al,(l98l) l. The tallow is brought from storage at 4°C, softened and the surfactant is mixed into the tallow. 2. The tallow and surfactant is allowed to come to equi- librium at the fractionation temperature. 3. The aqueous solution containing an electrolyte is added and diSpersed. 4. The aqueous diSpersion is centrifuged. 18 Table 3. SOURCE OF MATERIALS Material Source sodium dodecyl sulphate Fisher Scientific sodium citrate Mallinckrodt tallow CFS Continental l9 crystallization. The desired crystallization temperature, which was 40°C for all fractionations conducted, was main— tained by holding the beakers containing the tallow in a 40°C water bath. The samples were not agitated in a reproducible manner when the aqueous solution was diSpersed. The nonscalable batch fractionations follow both the Bussey, et al., (1981) and the Haraldsson (1974) fractionation procedures. The Haraldsson procedure was considered because it is similar to the Bussey, et al. procedure. Both procedures add the same chemicals, although treatment of the additions are different. Samples were prepared and stored in beakers which doubled as crystallization vessels. The storage tem- perature was 40C. The low temperature was necessary to retard oxidation of the tallow. To begin an experiment, a sample of tallow was softened in the 400C bath. After softening for a couple of hours the SDS (sodium dodecyl sulphate) was mixed into the partially crystallized tallow. The tallow was allowed to equilibrate for 18 hours at 400C. An aqueous solution containing an electrolyte was added to the equilibrated tallow and mixed until a uniform diSpersion was generated. The mixing was done by hand with a stirring rod. The contents of the aqueous solution is where the Bussey, et al., (1981) and the Haraldsson (1974) procedures differ. In the Haraldsson procedure the SDS is added with the aqueous solution. The Bussey, et al. procedure has the SDS added to 20 the softened tallow instead of the aqueous solution. The 18 hour equilibration time was not an optimum. Bussey, et a1. (1981) Specifies 18 hours as a sufficient time. The uniform diSpersion was allowed to sit for one hour. This is not an optimum condition but is a sufficient one deter- mined by Bussey, et al. (1981). The whole mixture was then centrifuged. The olein was poured Off and weighed. The stearin was recovered by heating the aqueous-stearin mixture to liquify the stearin in the stream and then centrifuging the stream to yield liquid stearin and the aqueous solution. Parts of this procedure required extreme care to ensure consistent results. The crystallization procedure had to be the same for quantitative comparison of results. Emulsifi- cation of the olein phase seemed to depend on crystallization conditions. The aqueous diSpersion of tallow had to be care- fully kept at the 40°C fractionation temperature while it was prepared for centrifugation. If it was not kept at 400C melting or solidification of the tallow occured. Keeping the centrifuge chamber at 35°C was necessary to keep the samples in the rotor from exceeding 400C during centrifugation. Checking the temperature of a water-filled centrifuge tube, which had been inserted into a tube hole in the rotor, was a good method to monitor the temperature actually encountered by the samples being centrifuged. A RC2-B DuPont Sorvall refrigerated centrifuge allowed accurate temperature control in the centrifuge chamber. 21 Nuke E 52 Temperature - — Controller - G - Tallow Samples \ ( \ I Water U U um Figure 2. NONSCALABLE BATCH FRACTIONATION EQUIPMENT. 22 Table 4. COMPARISON OF SCALABLE AND NONSCALABLEfPROCEDURES Scalable Nonscalable l. The partial crystallization l. The samples were cry- was conducted from the melt. stallized at a temperature 2. A crystallization of 20°C. temperature of 40°C was used 2. The samples were stored at for 18 hours. 400. 3. A steady mixing in a 3. The samples were allowed to system with a well defined equilibrize at 40°C for 18 hours. geometry was used. 4. There was not any agitation 4. The aqueous solution was ‘ during the crystallization or added and the stirring rate equilibrization times. was reduced to produce 5. The aqueous solution with or gentle agitation. without the SDS was added and 5. The diSpersion was mixed by hand to yield a uniform centrifuged. dispersion. 6. The diSpersion was centrifuged. 23 During the equilibrization of the tallow at the frac- tionation temperature care was taken to insure the tallow temperature was at the actual 400C fractionation temperature. The water bath used to hold the tallow at a fractionation temperature of 40°C typically had to be at 41°C to keep the tallow temperature at 400C. Comparison of results from different tallow samples required a careful preparation of samples. This was because, as shown earlier, the composition of tallow varies. Since tallow fractionally crystallizes, any drum or other container of tallow will likely have a nonuniform composition. Samples were prepared by melting and mixing tallow throughly and then separating the tallow into uniform samples. Since tallow varies from source to source, comparison of several sources is feasible only on a qualitative basis. SCALABIE FRACTIONATION The experiments were scalable because they were conducted in a vessel with known and reproducible geometry. The agitation system was well defined and reproducible. Power input calculations were possible. The temperature of the tallow was measured and controlled. If a scale-up of the apparatus was made the same results could be expected. The mixing vessel was a cylindrical, glass and baffled tank with a turbine impeller for mixing (see Figure 3.). Some of the characteristic dimensions are listed in Table 5. Further turbine impeller mixing information is found in Uhl 24 Meet Treneter Medlum Inlet end Outlet \ Turblne llnpeller Bettle end Heet Treneter Surtece Figure 3. SCALABLE BATCH FRACTIONATION VESSEL. 25 Table 5. TURBINE CHARACTERISTIC MEASUREMENTS Variable Value Variable Description D 0.40 FT. Impeller Diameter T 0.67 FT. Tank Diameter z 0.50 FT. Liquid Depth 0 0.25 FT. Clearance of Impeller from Bottom of the Vessel W 0.066 FT. Blade Width N 4 Number of Blades 1 0.098 FT. Blade Length .« 41. 1| II! 1:11! lulll. lull II. T 26 and Gray (1966). The scalable batch fractionations followed the Haraldsson (1974) procedure closely. The reason for this was that the Haraldsson procedure was better suited for this type of fractionation. The crystallization procedure of Haraldsson begins with liquid tallow and the chemical addition pro- cedure is recyclable. The Bussey, et al. (1981) procedure is not suitable for this type of experiment. A large scale fractionation can not begin with solidified tallow. The solidified tallow would not allow efficient heat transfer to occur. The addition of the SDS to the fat directly before the addition of the aqueous solution is not compatible with a large scale fractionation. Because the SDS will end up in the aqueous solution, recycling the aqueous solution is not possible. Because the SDS can not be separated from the solution, the next fractionation would be hit with double the required SDS. Approximately four liters of tallow were melted and put into the crystallization vessel. This allowed a liquid level high enough so a vortex was not formed during agitation. This condition was necessary to allow power calculations (Uhl and Gray, 1966). The turbine agitation was begun and the temperature of the tallow was allowed to cool to 400C. The temperature of the tallow was maintained at 40°C by adjusting the temperature of the heating medium, which was circulated through the heat 27 exchange tube in the crystallization vessel. The tallow was held at 40°C to crystallize for 18 hours. Based on experimental observations the required crystallization time may have been less than 18 hours. The aqueous solution containing the SDS and the electrolyte, sodium citrate, was then added to the partially crystallized tallow. The Speed of agitation is reduced when the aqueous solution is added. The reason for the reduction was the decrease in the solution viscosity. The whole diSpersion was gently mixed for a hour before centrifugation was begun. Coalescence was observed after 10 minutes of the gentle stirring. The general separation of layers existing after one hour,was established after 15 to 20 minutes. Centrifugation required a series of steps because the centrifuge rotor capacity was not large enough for the whole diSpersion. About two to three hours were needed to accomplish the centrifugation step. Care was taken to ensure the dis- persion remained at 4000 during this process. Heat transfer during crystallization was a problem when the total crystal mass exceeded 5 % of the tallow. The partially crystallized tallow became very viscous because of crystal-crystal interactions. To combat this problem, high rates of stirring were used during the crystallization step. If a scraped surface vessel was used, as the process would be designed to include, the high Speed stirring would not have been necessary. 28 CHARACTERIZATION QF_FRACTIONS The fractions generated were characterized in two ways; a quick melting range determination ensured a fractionation had been made and gas chromatographic fatty acid analysis gave a quantitative measure of unsaturated fatty acids versus saturated fatty acids for the fractions and for tallow. The melting range determination was done by allowing the olein fraction generated to solidify at room temperature. The olein fraction was then slowly heated until the solidified portion had completely melted. The temperature range of the melting was observed. For a 40°C fractionation all of the olein should have remelted by 400C. If some olein melted above 40°C, a good fractionation may not have been made. The fractionation was tried again after a careful check of the crystallization and centrifugation steps determined the cause of the problem. The melting point determination was always an indication of the sucess of the fractionation for crystallizations following the Bussey, et al. (1981) procedure. Since the procedure allowed equilibrization of the partially crystallized tallow, all the olein should melt at or below 40°C. In the scalable experiments, because the crystallization occurs from the melt, olein fraction melting temperatures above 40°C were encountered. By the time the scalable fractionations were conducted the fractionation problems had been solved. Therefore, 29 melting point determination was not used as a measure of fractionation sucess. The melting point was determined to characterize the scalable fractionations. The fatty acid analysis gave the fraction of each fatty acid in the triglycerides. The fatty acid composition of tallow was determined by the gas chromatOgraphic analysis of the tallow methyl esters. A boron trifluoride-methanol reagent was used to prepare the fatty acid methyl esters (Morrison and Smith, 1964). One drop of the tallow fraction was evaporated to dryness under nitrogen in a test tube fitted with a Taflon lined screw cap. A mixture of 25 %.boron trifluoride-methanol was mixed with 20 % benzene and 55 % methanol to form the reagent used with tallow. The drop of tallow fraction and one ml of the reagent were mixed together under nitrogen and the tube was closed with the screw cap. The tube was then heated at 1000C for 30 minutes, cooled and opened. The esters were extracted by adding two m1 pentane followed by one ml of water, shaking briefly and centrifuging until both layers are clear. The top organic layer was removed using a micrOpipette and placed in a clean, labeled vial. The methyl esters were now ready to be analyzed on a gas chromatograph. A Hewlett-Packard 5830A gas chromatograph was used. Some of the important operating conditions: i) the column packing was 15 % diethylglycol succinate (DECS) on 30 80 to 100 mesh Chromosorb WA (acid washed), (ii) the carrier gas flowrate was 25 ml/minute of nitrogen and (iii) the column Operating temperature was 190°C. The retention time and fraction of total area under each peak was automatically calculated and tabulated. All that remained was to identify the peaks with the particular fatty acid represented. The accuracy of the method, tested by a standard, was 0.5 %. PHOTOMICROSCOPY To better understand the phenomena associated with the fractionation process photomicroscopy was done at various stages of the process. The photomicroscopy was conducted on an American Optical Phase Star micrOSCOpe fitted with a Kodak 35 mm camera. The film used was Kodak Type 2415, a high resolution black and white film. D-l9 develOper was used with a develOping time of four minutes. The photomicroscopy was done in a 37°C temperature cubicle so that the samples photographed could be kept near the 400C fractionation temperature. Partially crystallized tallow, partially crystallized tallow with SDS mixed in the tallow, the aqueous dispersion of tallow and the cloudy olein phase were all photographed while magnified under the mi- crosc0pe. RESULTS AND DISCUSSION Photomicroscopy of the process steps provided a de- scription of the process. Photomicroscopy identified the problem of emulsified olein. The results of the nonscalable experiments testing the effect of various surfactant and electrolyte concentrations on the production of olein and emulsified olein are presented next. The results of the scal- able experiments , including mixing requirements for the dis- persion step, are next. Fatty acid analysis of the fractions and of tallow are presented last. PARTIAL CRYSTALLIZATION PhotomicrOSCOpy of the partially crystallized tallow yielded a pictorial view of crystal-crystal interactions. Figure 4 Shows partially crystallized tallow at 40°C. Note the spiny protusions from the generally round crystal masses. The mechanism by which these Spine-like protusions formed is not known, but they formed a round crystal mass. The size of the crystals in Figure 4 was estimated by using a photOgraph of a stage micrometer as a measuring tool. The round crystal masses in Figure 4 were estimated to average about 100 microns in diameter. The Spiny protusions were 20 to 50 microns long and less than two microns in diameter. A cylindrical shape was assumed for the protusions. These sizes were subject to variation depending on the crystallization 31 32 PARTIALLY CRYSTALLIZED TALIOW (lOOX MAGNIFICATION). Figure 4. 33 procedure. Figure 5 is partially crystallized tallow that was mag- nified 450x instead of the 100X that the tallow Of Figure 4 was magnified. The dark area is the main crystal mass. The figure shows the Spiny protusions of one crystal intersecting with the Spines of another in the area marked A. This helps to explain why a straight centrifugation or dry fractionation was not effective in separating the liquid and solid crystals from each other. The Spine-like crystals apparently created a mesh of solid tallow which traps the oil. Figure 6 Shows the results of a straight centrifugation of partially crystallized tallow at 40°C. An aqueous fractionation of the same tallow yielded 70 % olein at less than 5,000 x g centrifugal force. The best dry fractionation yielded 44 % olein at the imprac- tically high centrifugal force of 20,000 x g. SURFACTANT ADDITION The next step in the Bussey, et al. (1981) procedure is the addition of powdered sodium dodecyl sulphate, the sur— factant, to the partially crystallized tallow. The justi- fication for adding the SDS to the partially crystallized tallow is increased olein yield, according to Bussey, et al. Figure 7 shows partially crystallized tallow with SDS mixed into the tallow. The tallow in Figure 7 looks different from the other photographs of tallow for a couple of reasons. First a reverse phase picture was taken with the phase micrOSCOpe Figure 5. PARTIALLY CRYSTALLIZED TALIDW (450x MAGNIFICATION). 35 Fractionation Method 0 dry 0 aqueous 60 E :50 E $40 E 5 10 15 20 RELATIVE CENTRIFUCAL FORCE (1,000 x g) Figure 6. OLEIN YIELD VERSUS RELATIVE CENTRIFUCAL FORCE. 36 Figure 7. PARTIALLY CRYSTALLIZED TALIOW WITH SDS (450x MAGNIFICATION). 37 used. Secondly the tallow was crystallized in the scalable crystallization tank. In order to facilitate heat transfer the rate of agitation during crystallization was high. This produced crystals that resemble the spiny protusions found on the statically crystallized crystals. There were no crystal masses formed in this crystallization procedure. The Spot marked B on Figure 7 is a SDS phase. The SDS would have appeared black, but the phase was reversed by the micrOSCOpe. Because the SDS phase is clearly visible, the SDS is not very soluble in the partially crystallized tallow. The same type of SDS phase was observed in the statically cry- stallized tallow. The tallow crystals in Figure 7 were magnified 450x and individual crystals were barely distinguishable. The crystals appeared to be about 20 microns long and one micron or less in diameter, if a cylindrical shape was assumed. The letter 0 indicates an area of oil phase. The apparent nonsoluble nature of the SDS in the partially crystallized tallow raised the question of why the SDS should be added at this point. Other factors also questioned this addition. Recycling of the aqueous solution was not possible with the Bussey, et al. (1981) procedure. This would be a major economic disadvantage in a large scale operation. A comparison of methods was not conclusive as to whether an increased olein yield resulted when the method of Bussey, et al. (1981) was compared to that of Haraldsson (1974). (See Figures 13 and 14) 38 AQUEOUS DISPERSION The addition of the aqueous solution to the partially crystallized tallow with or without the SDS was the next step. Figure 8 Shows an aqueous diSpersion just after the aqueous addition. The area labeled D is aqueous solution with the dark area next to it being accumulated crystal mass. A large pool of olein is in the area labeled E. The area labeled F apparently had not dispersed as crystals and oil both are present. Figure 9 shows an aqueous diSpersion ready for centri- fugation. The important thing to notice here is the ring of aqueous emulsion Surrounding each drop of the oil. The letter C is in the middle of a drop of oil. The letter H is in the ring of clear aqueous solution surrounding the oil droplet. The exact nature of the thin stearin free aqueous layer surrounding the Oil drops was not known. The surfactant and electrolyte probably interacted to stabilize an oil- in- water emulsion. Figure 10 shows an emulsified oil border magnified 450x. The K in Figure 10 is in the middle of the Oil droplet. The layer of aqueous solution with no crystals in it, next to the oil, is easily observed around the L. EMULSIFIED OLEIN A problem encountered in the aqueous fractionation of tallow was the formation of a fourth phase during the centri- fugation of the aqueous diSpersion. In an ideal aqueous 39 Figure 8. INITIAL AQUEOUS DISPERSION (lOOX MAGNIFICATION). 4O Figure 9. AQUEOUS DISPERSION READY FOR CENTRIFUGATION (100x MACNIFICATION). 41 Figure 10. EMULSIFIED OIL BORDER (450x MAGNIFICATION). 42 fractionation, a centrifuge tube looked like tube A in Figure 11. The extra phase formed at the expense of the olein phase, as shown in the tube labeled B in Figure 11. The problems caused by this phase were reduced olein fraction yield and product loss. The product loss occured because the extra phase could not be economically recovered. It had to be heated to 100°C so that the aqueous part of the phase boils away. This was done experimentally because it was first thought that the layer was a solid tallow. That first impres— sion was proven false when the phase had to be heated to 1000C to clear the phase. Pictures of the phase revealed that it was emulsified olein. Figure 12 shows the emulsified olein photographed after having been centrifuged. The olein is the dark phase in Figure 12. Notice the thin light colored layer of water that surrounds the drOplets. This layer appeared much thinner in Figure 12 than it was in Figure 9, because all the excess aqueous solution from the layer surrounding the olein droplets was squeezed out by centrifugation. Normally the aqueous layer was completely broken by the force of centrifugation. The reason why it does not always break is probably related to a change in the chemical concentrations in the layer. SURFACTANT AND ELECTROLYTE CONCENTRATION TESTS It was theorized that the SDS, which is an emulsion stabilizer, (Davies and Rideal, 1961) might have caused the emulsified olein. Tests were conducted using various SDS 43 olein einusif ied olein stearin aqueous solution A B Figure 11. CENTRIFUGATION TUBES WITH FRACTIONATION PRODUCTS. Figure 12. EMUISIFIED OLEIN (lOOX MAGNIFICATION). 45 and sodium citrate concentrations. The idea was to control emulsification of the olein phase so consistent olein yields were achieved. This served to Optimize chemical levels. An experimental run consisted of samples which were carefully prepared so that quantitative comparisons were possible. Four different runs were conducted. It was important to note that a run applied to tallow samples that were prepared to be of uniform composition. Figure 13 shows the results of run number 1, olein yield versus the percentage of SDS based on the weight of tallow. Both the Haraldsson (1974) and Bussey, et al. (1981) methods of chemical addition were used. A peak olein yield was at- tained for both methods with a SDS concentration between 0.6 to 1.0 %. As the SDS concentration increased, any drop in olein yield was accompanied by an increase in the amount of emul- sified olein. The emulsified olein was not included as olein in the olein yield calculation. As the SDS concentration was reduced below 0.6 %, the olein yield steadily decreased. Figure 14 Shows the results for run 2 of the olein yield versus per cent SDS experiments. Each of the methods being compared was used to fractionate half of the samples. The overall olein yield in this run was less than expected because the crystallization temperature was lower than 400C. It was found to be 390C. However, it was the same for both the Bussey, et al. (1981) and Haraldsson (1974) methods. The trends revealed in Figure 14 were the same as those Observed 46 Experimental AHaraldsson Procedure D Busse et al 70 AS an A A [J 60 U R g 50 S A 4°" 30 20 C] J A 0.5 1.0 1.5 2.0 PERCENTAGE SDS (BY WEIGHT OF TALIOW) Figure 13. OLEIN YIELD VS. PERCENTAGE SDS: RUN 1. PERCENTAGE OLEIN YIELD 70 (S) e 0" 0 .IS 0 00 O 20 47 EXperimental AHaraldsson Procedure aBusse etal l> l> a E] l> A A 0.5 1.0 1.5 2.0 2.5 PERCENTAGE SDS (BY WEIGHT OF TALLOW) Figure 14. OLEIN YIELD VS. PERCENTAGE SDS: RUN 2. 48 in Figure 13. It should be noted that the electrolyte level for runs 1 through 3 was 3.6 % sodium citrate in the aqueous solution. The volume ratio of aqueous solution used to partially crystallized tallow was 0.5 : 1.0 for all runs. Figure 15 shows the third run conducted to determine olein yield versus per cent SDS used. All samples in run 3 were fractionated by the method of Bussey, et al. (1981). The results of runs 1 and 2 showed no difference in yield between the two methods used. The lack of difference was why one method was used for all samples in run 3. A wider range of SDS concentrations was used for run 3 than was used for run 1 or run 2. Concentrations all the way up to 4.0 % were tested. This compared to the 0.6 % SDS concentration Specified by Bussey, et al. (1981). At concen- trations greater than 1.3 %, a large part of the olein was lost as emulsified olein. This was Shown by the very low olein yields achieved at the higher SDS concentrations. The SDS concentration at the onset of serious emulsified olein formation was not the same for runs one through three. An explanation for these differences was a variation in the size of crystals present in the different runs. Slightly different crystallization procedures were probably used. The room temperature during crystallization was different or the samples were put into the 40C storage more quickly for one run than for another. Either of these conditions would affect the size of the crystals formed. Experimental Procedure Bussey et al 0 trial 1 GO 01 O 40 PERCENTAGE OLEIN YIELD 30 20 a 1.0 2.0 3.0 4.0 PERCENTAGE SDS (BY WEIGHT 0F TALLOW) Figure 15. OLEIN YIELD VS. PERCENTAGE SDS: RUN 3. 50 The results of the scalable fractionations also helped to identify crystal size as a factor in the formation of emul- sified olein. The type of crystal may have also been important. At a low SDS concentration, 0.6 %, significant or total emul- sification of the olein was encountered when a scalable frac- tionation was conducted. The only difference between the scalable and nonscalable fractionations noticed was the small crystals produced in the scalable fractionations. A further discussion of these experiments is found in the scalable fractionation section. It was clear from the experiments that the concentration of SDS had an effect on the viscosity of the diSpersion. At SDS concentrations below 0.6 % a steady decrease in the ease of pouring the diSpersion was observed as the SDS concentration was decreased. At about 0.2 %, the viscosity increased enough that pouring the dispersion was nearly impossible. An experimental run keeping the concentration of SDS constant at 0.6 % and using various electrolyte concentrations in the aqueous phase was conducted. The results are Shown in Figure 16. The aqueous solution to partially crystallized tallow volume ratio used was O.5:l.0. The experiment used the method of Bussey, et al. (1981). Olein yield rose with increasing electrolyte concentration up to about 5.0 % sodium citrate, then olein yield leveled off. Electrolyte concentrations up to 11.5 % were tested. Increased electrolyte concentrations did not PERCENTAGE OLEIN YIELD Experimental Bussey et al otrial 1 Procedure atrial 2 2.0 4.0 6.0 80 10.0 PERCENTAGE ELEC TROLY TE Figure 16. OLEIN YIELD VS. % ELECTROLYTE: RUN 4. 52 affect the formation of emulsified olein. Some emulsified olein was observed in samples with electrolyte concentrations of 5.0% and higher, but the amount of emulsification was not significant. SCALABLE EXPERIMENTAL RESULTS The scalable experiments were conducted to determine some of the process agitation requirements on a reproducible basis. The general procedure followed was that of Haraldsson (1974). The method of Bussey et al (1981) was not appropriate for these experiments for reasons previously discussed. Heat transfer during the crystallization step was a problem. Due to the ambient temperature of 20°C, the crystallization temperature of 40°C and the large surface area to volume ratio of the scalable vessel, the tallow tended to cool too much. While the tallow was completely liquid no problem was observed. After crystallization formed approximately 5% solids the viscosity of the tallow had increased greatly. It was necessary to increase the rate of stirring at this point. Up to this point 60 rpm provided adequate mixing. 260 rpm was the rate of stirring that eliminated the problems that resulted from the increased viscosity of the tallow. The increased agitation rate caused other problems. Power consumption for a normal crystallization could not be estimated. The size of crystals resulting from a normal stirred crystallization was not found. Total solidification 53 occurred at any stirring rate much below 260 rpm. The high rates of stirring caused excessively small crystals as shown in Figure 7. The increased agitation also caused tallow to be Splattered up the propeller shaft and onto the crystal- lization vessel walls. The problem of small crystals added another cause for the formation of emulsified Olein. The small crystals produced were apparently reSponsible for a problem with emulsified olein, even at low concentrations of SDS. All the olein was emulsified at a SDS concentration of 0.6% and an electrolyte concentration of 3.6%. This result suggested that emulsified olein formation was a function of crystal size. The aqueous diSpersion step was defined by the scalable experiments. The gentle mixing caused by a power input of approximately 2.9 Hp. per 1,000,000 pounds of diSpersion was adequate to contact the partially crystallized tallow and the aqueous solution completely. This Slow agitation allowed a coalescence of the oil droplets to occur. The time required for this step was reduced to 45 minutes, because no change in the diSpersion was observed after 20 minutes. FATTY ACID ANALYSIS The fatty acid analysis of the olein products from several of the chemical concentration experiments were analyzed for uniformity of the olein composition versus 5‘+ the changing chemical concentrations. The results were expressed in terms of the per cent unsaturated acids in the olein versus the chemical concentration. Figures 17 and 18 Show this information. Figure 17 was the per cent unsaturated acids in the Olein versus the per cent SDS. Figure 18 Shows the per cent of unsaturated acids versus the per cent electrolyte in the aqueous solution. Figure 17 was generated from run 3 of the SDS concentration experiments. There was no reason to believe various SDS concentrations would cause fatty acid composition differences in the olein or other fractions. Both of the figures Show no trends in the distribution of fatty acids based on the concentration of surfactant and electrolyte. The scatter was small compared to the variation possible for each fatty acid of t 0.5 %. The overall compositions of the tallow, the Olein and the stearin fractions are summarized in Table 6. The individual fatty acid compositions are summarized in Table 7 for a 40°C fractionation. These tables Show a significant difference in the fatty acid composition of the fractions produced. The fatty acid compositions reported are typical for 400C fractionations conducted with tallow from this source. 8% o U" 01 01 01 01 o PERCENTAGE OF UNSATURATED ACIDS IN THE OLEIN FRACTION 55 EXperimental Procedure Bussey et al : ru n 3. 0 trial 1 e emulsified olein A trial 2 1.0 2.0 30 4.0 PERCENTAGE SDS Figure 17. % UNSATURATED ACIDS VS. % SDS. PERCENTAGE OF UNSATURATED ACIDS IN THE OLEIN FRACTION 50.0 55.5 55.0 54.5 54.0 53.5 EXperimental Procedure Bussey et al 0 trial 1 A trial 2 2.0 4.0 6.0 8.0 10.0 PERCENTAGE ELEC TRO LY TE Figure 18. % UNSATURATED ACIDS VS. % ELECTROLYTE. 57 Table 6. SATURATED AND UNSATURATED FATTY ACID COMPOSITIONS FOR TAIIOW AND FRACTIONS OF TALLOW Tallow Percent Percent Species Saturated Unsaturated Tallow 48.8 51.2 Olein 45.1 54-9 Stearin 57.4 42.6 Table 7. FATTY ACID COMPOSITION OF TALLOW AND FRACTIONS Common Name Tallow Olein Stearin Myristic acid C14:0 3.16 3.09 3.32 Palmitic acid Cl6:0 25.55 24.33 28.40 Palmitoleic acid C16:1 4.48 4.67 4.04 Stearic acid Cl8:0 19.66 17.78 24.05 Oleic acid 018:1 43.43 45.80 37.90 Linoleic acid C18:2 2.32 2.73 1.34 Minor component fractions omitted. The fractionation temperature was 40°C. 58 CONCLUSIONS 1. The control of the formation of emulsified olein is a critical factor for the sucessful fractionation of tallow. The formation of emulsified olein is a function of surfactant concentration. It is also a function of the crystal size formed with small crystals causing more emulsified olein to form. 2. For crystal sizes of approximately 100 microns, increasing the concentration of the surfactant in an aqueous fractionation increases the olein yield up to about 1.0 % sodium dodecyl sulphate by weight of the tallow. Above 1.3 % sodium dodecyl sulphate emulsified olein production increases greatly resulting in significant product loss. 3. Agitation of the tallow during the partial crystal- lization causes extremely small crystals to be formed. They were cylindrical in shape, about 20 microns in length and one micron or less in diameter. The stirring rate was 260 rpm in a turbine impeller vessel. The fractionation of these small crystals will produce emulsified olein, even at low surfactant concentrations. 4. Increasing the electrolyte concentration in an aqueous fractionation increases olein yield until the elec- trolyte concentration is above 5.0 %, then the olein yield levels off. The electrolyte used was sodium citrate. APPENDICES APPENDIX I PROCESS FLOWCHART The experiments conducted and the information gathered have allowed the preparation of a process flowchart. The process material and energy balances were based on a capacity for processing 50 tons of tallow per day. The time necessary for crystallization was taken to be six hours. This time is believed to be close to the time necessary, but has not been determined experimentally.' The process flowchart was patterned after fractionations made to produce a pourable shortening. The process features both a 40°C fractionation and a 33°C fractionation. The 33°C fractionation is made on the olein fraction from the 40°C fractionation. The 33°C olein product is the pourable short- ening. The 330C Stearin has potential as a cocoa butter extender, if the two fractionation temperatures are suitably adjusted. The flowchart process and products are summarized in Figure 19. Figure 20 is the tallow aqueous fractionation flow diagram. Table 8 has the material and energy Specifications for the process. Table 9 is a list of the proposed flowchart equipment. The tallow starts the process in a storage tank in the liquid state. It is pumped to a crystallizer through stream 59 60 TALLOW o PRIMARY 0 40 C 0m” 33 C FRACTIONATION —"_.' FRACTIONATION PRIMARY SECONDARY SECONDARY STEARIN OLEIN sTEARm Figure 19. PROPOSED PROCESS PRODUCTS AND FRACTIONATION SCHEME. 61 Figure 20. .PRELIMINARY TALIlOH AQUEOUS FRACTIONATION FLOW DIAGRAM. 62 mm oa.m- mmm.a¢a mmm.m cmH. con. man. .paH Sesame nsoosa< Swmcsooom mm o: OM64“ Nmm.mm mmm.m o 004 0 2+5“ 93.8 sauna—fig mm 03 om.m~ ll mmm.m o 004 o .9200 Cacao insanm am no om.am In. mmm o oo.H o .ssco sarcasm Shannan susceha om mw ow.mn .II 0mm.m o o oo.H .pcou mfiozoom msomsw< mumefiym 0H om 0:.n: .pcou Aemwsv papa: weflaoou ma ma oo.amu .psou worms mafiaooo AH or oo.mH roo.ra ora.m o o oo.H .psH cfioscor mucosa< sarcasm SH 0: oo.NH roo.ma bra.m o o oo.H .esH cacaoor mucosaa swssawa mH o: ow.mfi II mamam o o 004 .pcoo 3050mm mucus?“ firefihm 3H .paH .mzmxmz w50o5w< anneanm ma om ow.om .II wwm.m o o oo.H .Saoo machomm meoosw< hensfihm HH no Hm.an ll. mmm.m 0 0mm. own. .escu cawmopm mucosa< Sargahm 0H m: mn.am .II mmm.m omH. OOH. own. .paco sawmopm msoosa< Swmstm a no Hm.am .II mmm.m 0 0mm. om». .ecco aflwmopm msccsaa awnsfiwa m 0: ma.: .I. mmm.m omm. o emu. .cscu sawmopm mscoaaa sarcasm a 0: HO.@ In. aro.c nmfi. com. mam. .ecco Sedans nscoaaa h or Ho.o .Il new.w mmfl. con. man. .paou soaflme msoosa< m or Ho.b Soc.orH Sow.c mNH. com. mam. .esH acHHme mucosaa a as Ho.o aoc.rmfi Sbo.w mNH. com. mam. .psH acfifime nacosaa m mm om.mm mor.bHH Abfl.s o oo.H o .psH chHme m mm om.mm Scr.rflfl aofi.a o oo.H o .paH ecHHae H o Amu\:amv gaseoa muamm>< quom QHSGHS omr mm»e rmmzsz .azma smearezw meamzoga mmaz Aeronz va oneHmomzoo rose oneaHmomma rammem mogm wummzm 92¢ A< mHgom mHaqu omr Ease mmmzsz .mzme Sugarezm meaazoqa mmaz Aemonz wmv zOHSHmomzoo :oqa ZOHHEHmommm zammem A.a.eecov m cases 64 Table 9. FIOWCHART EQUIPMENT DESCRIPTION T1 T2 {3 CE1 CE2 CE3 CE4 C1 C2 V1 V2 V3 V4 HXl HXZ Tallow Storage Primary Olein Holding Tank Primary Stearin Storage Tank Secondary Olein Product Storage Primary Aqueous Solution Holding Tank Secondary Stearin Product Storage Tank Secondary Aqueous Solution Holding Tank Primary Precentrifugation Holding Tank Secondary Precentrifugation Holding Tank Primary Centrifuge Primary Stearin Recovery Centrifuge Secondary Centrifuge Secondary Stearin Recovery Centrifuge Primary Crystallizer Secondary Crystallizer Stearin Recovery Scraped Surface Heat Exchanger Secondary Stearin Recovery Scraped Surface Heat Exchanger Stream Interchange Heat Exchanger (Scraped Surface) Stream Interchange Heat Exchanger (Scraped Surface) Primary Aqueous Cooling Heat Exchanger Secondary Aqueous Cooling Heat Exchanger 65 2 and cooled in C1. The tallow is left to crystallize for 6 hours in CI. An aqueous solution is pumped from T5 to Cl and mixed with the partially crystallized tallow. The temperature of the tallow and the aqueous solution is 400C. The aqueous solution contains sodium citrate and sodium dodecyl sulphate. The diSpersion of tallow and aqueous solution is pumped to T3 after 45 minutes of mixing. A continuous flow of the aqueous diSpersion is pumped from T3 to CE1. CE1 is the primary fractionation centrifuge. A primary olein product and an aqueous stearin mixture leave the centrifuge. The primary Olein flows to T2 before it goes through the second fractionation. The aqueous stearin mixture flows to V3 where it is heated by the aqueous solution recycle stream. It then flows to V1 and is further heated with steam to melt all the stearin. The mixture of liquid stearin and aqueous solution is then centrifuged by CE2. From CE2 a hot aqueous solution and a primary stearin pro- duct are produced. The aqueous solution flows through V3 heating the aqueous stearin mixture and being cooled itself. It then flows through HXl which uses cooling water to lower the aqueous solution temperature to 40°C. The aqueous solution then enters T5 where it is stored until needed in C1. The liquid stearin flows from CE2 to T3 where it is stored. The primary olein stored in T2 flows through the same procedures in the secondary fractionation. From the primary olein a secondary stearin product and a pourable shortening 66 are produced. The stearin products both make up about 20% of the original tallow. The pourable shortening accounts for 60 % of the original tallow. The energy balances were based on 330C olein having an enthalpy of 0.0. A tallow enthalpy curve was used to de- termine sensible heats for the liquid and solid phases and a latent heat of solidification. Figure 21 shows the tallow enthalpy curve. The straight part of the curve in the low temperature area indicates totally solidified tallow. The straight part of the curve in the high temperature region indicates totally liquified tallow. The solid phase line was extrapolated and found to be almost parallel to the liquid phase line. The difference between the two lines was 25 BTU per pound. This value was used for the latent heat of solidi- fication. The slope of the solid and liquid phase lines was found to be 0.56 BTU/LB 0F. This value was used as the sensible heat of the liquid and solid. To check the latent and sensible heat values, calculation of the enthalpy of 104°F tallow was done using the experi- mentally determined 75 % liquid and 25 %.solid values. Using 40°F as a basis the enthalpy was calculated as follows: ENTHALPY CALCUIATED=O'56 BTU/13°F X (104-400F)+ 0.75 x 25 BTU/LB == 54.6 BTU/LB. From the enthalpy diagram a value of 57.0 BTU/LB is obtained. The difference between these values is not Significant when 67 compared to possible differences in the tallow composition. Table 10 shows enthalpies for each of the fractions encountered. lll Ch :3 ENTHALPY ‘_(BTUILB) 68 50 70 90 110 TEMPERATURE (°P) Figure 21. TALLOW ENTHALPY DIAGRAM. 130 69 Table 10 ENTHALPIES OF FRACTIONS Fraction Primary Olein Primary Stearin Secondary Olein Secondary Stearin Aqueous Solution Enthalpy description -6.25BTU/LB at 330C rising linearly to 7.06BTU/LB at 40°C rising linearly to 32.26BTU/LB at 65°C. -25.OBTU/LB at 33°C rising linearly to -l7.94BTU/LB at 40°C rising linearly to 22.18BTU/LB at 55°C rising linearly to 32.26BTU/LB at 65°C. 0.0BTU/LB at 33°C rising linearly to 32.26BTU/LB at 65°C. -25.OBTU/LB at 33°C rising linearly to 7.06BTU/LB at 40°C rising linearly to 32.26BTU/LB at 65°C. 0.0BTU/LB at 330C rising linearly to 57.6BTU/LB at 65°C. APPENDIX II MIXING POWER CALCULATIONS The calculation of power input by the turbine impeller was based on data correlations by Bates, Fondy and Corpstein (1963). A dimensionless power number is correlated versus a Reynolds number for specific types of turbine impeller blades. The w/D ratio is also important to the blade type. This is the ratio of the blade width to the impeller diameter. For the turbine impeller of the scalable vessel the w/D ratio was 1/6. The disk styled turbine impeller has curves plotted for w/D ratios of 1/5 and 1/8. The correct numbers were obtained by interpolating between the two values represented. The power number: P gC N _ . P..— /° N3D5 The Reynolds number: N D2 N Re::----° /AL. The proximity of a turbine impeller to the free surface of the liquid has negligible effect on the power as long as full baffling exists and no vortex is formed. The calculations presented do depend on the solution viscosity used. The solution viscosity is changing and is not measurable with the solids in the solution. The data presented and calculations presented are for 70 71 the aqueous diSpersion step of the aqueous fractionation process. This is the mixing of the aqueous solution and the partislly crystallized tallow. The raw data was acquired from the scalable experiments conducted. Some of the important variable values of the scalable system were: i/ot-58 LB/FTB, ii) N=40rpm, iii) D=0.4O FT and #:1-10 op. The Reynolds number was calculated below for various viscosities. (58 LB/FT3)(40 min‘1)(0.40 FT)2 -(5cp)(6.72X10.uLB/FT sec cp)(60 sec/min) NRe =l,841.3 NRez9,206.3 I/“a-l cp. NR6: 920.6 #:10 cp. Table 11 POWER REQUIRED FOR THE AQUEOUS DISPERSION N /J~ Power required 4.1 1 cp. 4.07x10’5Hp/6 liters 3.39 Hp/lO°LB. 3.4 5 cp. 3.38x10‘5Hp/6 liters 2.82 Hp/lO°LB. 3.24 10 cp. 3.22x10’5Hp/6 liters 2.68 Hp/10°LB. APPENDIX III FRACTIONATION AND FATTY ACID ANALYSIS DATA 72 73 Table 12 DRY FRACTIONATION DATA Centrifuge Speed RCF ( x g) Olein yield 4,000 rpm 1,929 15.6 % 5,500 rpm 3,647 17.8 % 8,500 rpm 8,711 27.3 % 10,000 rpm 12,057 39.4 % 11,500 rpm 15,946 41.0 % 13,000 rpm 20,377 41.9 % 74 Table 13 SURFACTANT CONCENTRATION FRACTIONATION DATA Run 1 TALLOW WEIGHT(grams) OLEIN WEIGHT OLEIN % SDS GROSS TARE NET GROSS TARE NET YIELD 0.00 338.1 179.5 159.6 183.7 107.6— 76.1 52.77% 0.19 349.1 187.9 161.2 213.7 108.6 105.1 65.2 % 0.38 350.3 193.5 156.8 216.9 109.6 107.3 68.4 % 0.57 341.6 183.4 158.2 218.3 107.7 110.6 69.9 % 1.20 340.6 190.5 150.1 205.0 105.0 100.0 66.6 % 1.73 352.6 190.5 162.1 All Emulsified 0.0 % Haraldsson (1974) Procedure 0.19 351:6 192.0 159.6"204T4 108.7 95.7 60.0 % 0.40 342.4 192.4 150.0 203.4 108.1 95.3 63.5 % 0.57 329.2 176.2 153.0 216.9 112.1 104.8 68.5 % 0.80 332.9 185.5 147.4 208.5 107.5 101.0 68.5 % 0.97 348.4 194.3 154.1 200.0 93.4 106.6 69.2 % 1.17 340.8 186.5 154.3 126.9 106.8 20.1 13.0 % Bussey, et al. (1981) Procedure Run 2 0.13 346.4 191.3 155.1 145.9 108.1 37.8 24.4 % 0.32 348.8 192.0 156.8 183.8 93.4 90.4 57.7 % 0.62 331.0 185.5 145.5 189.5 104.2 85.3 58.6 % 0.97 354.0 189.6 164.4 208.2 105.0 103.2 62.8 % 1.50 338.7 186.5 152.2 All Emulsified 0.0 % 2.40 350.2 194.3 155.9 All EmuISified 0.0 % Haraldsson (1974) Procedure 0.19 335.0 176.2 158.8 182.8 110.4 73.4» 45.6 %: 0.42 335.2 190.9 144.3 169.8 109.1 60.7 42.1 % 0.59 332.8 179.6 153.2 192.2 106.7 85.5 55.8 % 0.86 350.5 187.9 162.6 201.1 107.7 93.4 57.4 % 1.15 345.8 189.6 156.2 205.3 109.6 95.7 61.3 % 1.44 333.1 173.6 159.5 201.8 99.7 102.1 64.0 % Bussey, et al. (1981) Procedure Run 3 0.33 330.3 179.6 150.7 197.7 107.6 90.1 59.8 % 0.59 344.1 192.0 152.1 216.6 112.1 104.5 68.7 % 1.00 339.2 191.3 147.9 204.6 108.6 96.0 64.9 % 2.00 340.1 189.6 150.5 189.7 98.9 90.8 60.3 % 2.92 343.6 189.6 154.0 166.6 108.7 57.9 37.6 % 3.91 346.5 190.5 156.0 149.1 106.2 42.9 27.5 % 0.32 348.7 194.3 154.4 193.4 104.4 89.0 57.6 % 0.57 340.5 183.4 157.1 201.3 103.8 97.5 62.1 % 1.08 250.1 176.2 73.9 153.8 107.8 46.0 62.2 % 2.00 341.3 190.9 150.4 166.8 110.1 56.7 37.7 % 3.08 332.6 186.5 146.1 . A11 Emulsified 0.0 % 4.06 323.9 173.6 150.3 158.9 106.7 52.2 34.7 % Bussey, et al. (1981) Procedure 75 Table 14 ELECTROLYTE CONCENTRATION FRACTIONATION DATA Bussey, et al. (1981) Procedure (0.6 % SDS, 0.5 Volume Aqueous to 1.0 Volume Tallow.) % ELECTROLYTE TALLOW WEIGHT (grams) OLEIN WEIGHT OLEIN GROSS TARE NET GROSS TARE NET YIELD 0.5 349.3 193.5 155.8 Too Thick to Pour. 1.96 345.6 190.9 154.7 185.5 108.5 77.0 49.8 % 3.47 347.4 190.5 156.9 209.9 108.1 101.8 64.9 % 4.76 348.1 192.4 155.7 219.0 104.4 114.6 73.6 % 7.41 341.1 183.4 157.7 223.3 109.6 113.7 72.1 % 9.09 343.5 191.3 152.2 216.6 104.2 112.4 73.9 2 1.96 336.2 185.5 150.7 196.1 108.6 87.5 58.1 % 3.47 348.1 189.6 158.5 223.5 112.1 111.4 70.3 % 4.76 341.3 186.5 154.8 207.9 107.7 100.3 64.7 % 6.50 349.5 192.0 157.5 206.9 110.1 96.8 61.5 % 9.10 331.6 179.6 152.0 207.4 107.8 99.6 65.5 % 11.50 343.4 187.9 155.5 201.4 107.6 93.8 60.3 % ACTUAL AND NORMALIZED FATTY ACID COMPOSITIONS: 76 Table 15 RUN 3 SAMPLE 14:0 14:1 FATTY 16:0 16:1 ACIDS 18:0 18:1 18:2 18:3 ACTUAL NORMAL ACTUAL NORMAL ACTUAL NORMAL ACTUAL “13 NORMAL ACTUAL 415 NORMAL ACTUAL 416 NORMAL ACTUAL 417 NORMAL ACTUAL 421N0RMAL ACTUAL NORMAL ACTUAL 423 NORMAL ACTUAL “24 NORMAL ACTUAL NORMAL ACTUAL 300LNORMAL CTUAL 300 ORMAL 410 411 412 422 425 3.003 53.150 2.952 53.110 2.903 3.080 3.015 3.180 3.005 3.170 3.010 3.160 2-995 3.150 3.046 .3.210 2.892 3.050 2.915 3.060 3.236 3,450 3.089 3.240 2.863 53.030 2.887 3.050 1.215 1.280 1.245 1.310 0.947 1.000 0.871 0.920 0.938 0.990 1.119 1.170 1.182 1.240 1.312 1.380 1.145 1.210 1.163 1.220 1.110 1.180 1.231 1.290 1.186 1.260 0.878 0.930 23.025 4.280 24.190 4.500 23.028‘“4i657 24.290 22.875 24.250 23.131 24.400 23.337 24.640 23.397 24.560 23.246 24.430 23.185 24.440 22.963 24.200 23.006 24.170 23.454 247980 23.313 24.470 24.176 25.600 23.842 22.895 4.910 4.378 4.640 4.356 4.590 4:608 4.860 4.481 4.700 4.536 4.770 4.528 4.770 4.4467 4.690 4.201 4.410 5.003 5.330 4.367 4.580 16.211544.149 17.030 46.370 16.343 43.487 17.240 45.860 161863743.500 17.870 46.110 16T586‘43.873 17.490 46.270 16.606“43.102 17.530 45.500 167220 43.903 17.030 46.080 16.146 43.891 16.970 46.130 16.149 43.601 17.020 457950 16.661 43.541 17.560 45.890 16.920 43.974 17.780 46.210 15.368 42.612 167370 45.380 15.966*44.211 16.760 46.410 4.216419.038440.182 4.470 4.270 4.510 20.160 42.560 18.819 41.022 19.900 43.370 2.711 2.850 2.575 2.720 2.293 2.430 2.552 2.690 2.556 2.700 2f611 2.740 2.568 2.700 2.467 2.600 2.495 2.630 2.414 2.540 2.541 2.710 2.507 2.630 2.126 2.250 2.174 2.300 0.609 0.640 0.529 0.560 0.590 0.630 0.431 0.450 0.570 0.600 0.543 0.570 0.592 0.620 0.594 0.630 0.600 0.630 0-575 0.600 0.580 0.620 0.584 0.610 0.636 0.670 0.699 0.740 77 Table 16 ACTUAL AND NORMALIZED FATTY ACID COMPOSITIONS: RUN 4 SAMPLE 14:0 14:1 16:0 16:1 18:0 18:1 18:2 18:3 500 ACT- 3-004 0.883 24.293*‘4.257 18.686*41.291 2.206“0.452 NOR. 3.160 0.929 25.552 4 .478 _9. 655 43. 431 2.320 0.475 501 ACT. 3.739 0 658 226184 4 545 17 9% 39 756 2-533 0.354 9 928*23. 554 *4.513 16.452 43.520 27454’ 0:484 980 24.810 4.750 17.330 45.830 2.580 0.510 060 23(781 5.053 15.325 42. 659 2.359 0.563 1 . 016.2 04 . . 0.600 ACT. 3.051 523 NOR. .3.210 ACT. 3.378 . . 0 524 : 23 17.071 ACT. 0.64.618. 1141.866 2.66 0 510 . 0. . 12 17.1 3.. 0. 0 NOR. 3.084 0.937 24.396 4. 649.18. 066 45. 797 2.460 0.611 511 ACT. 2. 928’ 0.29 23. 204 4. 319 17.156‘43.649 2.129 0.533 NOR. .3. 090 0.875 24 .491 4.559 18.197 46.068 2.247 0.563 512 ACT. 3.074 1. 005 23.305 *4.388 16.137 43.561 2.527 0.600 NOR. .3. 248 1.062 24.623 4.636 17.102 46.025 2.670 0.634 513 ACT. 2. 969' 0.876 23.202 4:445 167938 43.507 2.364 '0.510 NOR. 3.131 0.924 24. 972 4.688 17.865 45.888 2.493 0.538 514 ACT. 2.919 1.172 22 .978 4:448 16.639 43. 969' 2:450 0.552 NOR. 3.070 1. 230 24.160 4.680 17.490 46. 220 2.580 0.580 520 ACT. 2.948 0.922 23. 064’ 4.269 16. 771344?.194“*2. 327 0.501 NOR. .3.100 0.970 24.280 4.490 17.650 46.520 2. 450 0.530 521 ACT. 2.933 0.881 23.081 4:426 16.864 43.449 2.594 0.649 NOR. 3.091 0 29 24.327 4.665 17.775:45.795 2.734 0.684 0. 0. 1. 1. 0 0 e e 3090 ‘ 7 ' 525 NOR. 3.060 .9m 24. 590 4. 670 18.040 45.650 2.400 0.660 522 ACT. 2.887 1.170 23.058"4“415 17. 058F43. 115 2.425 0.7187 NOR. 3.040 1. 230 024 310 4 .650 17.980 45.460 2.560 0.760 ACT. =ACTUAL NOR . ==N0RMAL_12ED 78 Table 17 SATURATED VERSUS UNSATURATED FATTY ACID DATA SAMPLE SATU- UNSATU- 95 NUMBER RATED RATED SDS comm“ Run 3 410 44.37 55.63 0.33 Olein fraction 411 44.64 55.36 0.59 Olein fraction 412 45.20 54.80 1.00 Olein fraction 413 45.07 54.93 2.00 Olein fraction 415 45.34 54.66 3.91 Olein fraction 416 44.74 55.26 2.92 Recovered emulsified olein 417 44.55 55.45 3.91 Recovered emulsified Olein 421 44.67 55.33 0.33 Olein fraction 422 44.81 55.19 0.57 Olein fraction 423 45.01 54.99 1.08 Olein fraction 424 44380 55.20 2.00 Olein fraction 425 44.47 55.53 4.06 Olein fraction Run 4 500 48. 37 51.63 — Tallow 501 49.83 50.17 - Tallow 510 45.55 54.45 0.60 9.09 % electrolyte olein 511 45.69 54.31 0.60 7.41 % electrolyte olein 512 44.97 55.03 0.60 4.76 % electrolyte 016111 513 45.47 54.53 0.60 3.47 % electrolyte olein 514 44.72 55.28 0.60 1.96 % electrolyte olein 520 45.03 54.97 0.60 1.96 % electrolyte olein 521 45.19 54.81 0.60 4.76 % electrolyte olein 522 45.33 54.67 0.60 6.50 % electrolyte olein 523 45.35 54.65 0.60 9.10 % electrolyte olein 524 45.11 54.89 0.60 11.5 % electrolyte olein 525 45.69 54.31 0.60 3.47 %.e1ectrolyte olein 79 LITERATURE CITED Alfa-Laval,"Lipofrac Fractionation of Fats and Oils," Tumba, Sweden (1977). Bates, R.L., P.L. Fondy and R.R. Corpstein, "An Examination of Some Geometric Parameters of Impeller Power," Ind. Eng. Chem. Process Design and Deve10pment 2, 310 (1963). Braae, B., "Selection of Refining and Fractionation Methods in the Manufacture of Edible Products from Animal Fats," Tumba, Sweden (1976). Bussey, D.M., T.C. Ryan, J.I. Gray and M.E. Zabik, "Fractionation and Characterization of Edible Tallow," g._Food Sci. 46, 526 (1981). Davies, J.T. and E.K. Rideal, Interfacial Phenomena, Academic Press, New York (1963). DuPont Sorvall, Qperating Instructions for the Sorvall RCZ-B Automated Superspeed Refrigerated Centrifuge, Newton, Conneticut‘(l973). Haraldsson, G.,"The Lipofrac System and Fractionation of Palm Products," Paper presented at the Palm Oil Symposium organized by the Society of Chemical Industry, London (1974)- Kromer, G.W. and S.A. Gazelle, "Fats and Oils Situation," No. 275, ERS, USDA, Washington D.C. (1974). Kromer, G.W., "Economic Aspects of the Vegetable Oils and Fats Industry in the united States," Presented at the Inter- national Trade and Development Conference, United States Economic Commission for Asia and the Far East, Batelle Seattle Research Center, Seattle, Washington (1974). Luddy, F.E., J.W. Hampson, S.F. Herb and H.L. Rothbart, "DeveIOpment of Edible Tallow Fractions for Specialty Fat Uses," g._Amer. 011 Chem. Soc., 59, 240 (1973). Morrison, W.R. and L.M. Smith, "Preparation of Fatty Acid Methyl Esters and Dimethyl Acetals from Lipids with Boron Fluoride—Methanol," J. Lipid Res., 5, 600 (1964). Mullin, J.W., Crystallisation, 2nd. Edition, CRC Press, Cleveland, 0hio(l972). 80 Rek, J.H.M., "Process for Separation of Triglycerides in an Aqueous System," U.S. Patent 4,040,687 (1977). Swern, D., M.w. Formo, E. Jungermann, F.A. Norris and N.0.V. Sonntag, Bailey's Industrial Oil and Fats Products, 4th. Edition, John Wiley And Sons, New York (19797. Taylor, H.H., F.E. Luddy, J.W. Hampson and H.L. Rothbart, "Suitability of Fractionated Beef Tallow for Other Fats and Oils in the Food and Confectionary Industries: An Econgmic Evaluation," g._Amer. Oil Chem. Soc., 53, 491 197 . Tirtiaux, A., "Tirtiaux Fractionation: Industrial Applications," g._Amer. 011 Chem.Soc., ég, 473 (1983). Uhl, V.W. and J.B. Gray, Mixing, Volume 1, Academic Press, New York (1966).