Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
  • B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
  • B01D3/36—Azeotropic distillation
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B1/00—Production of fats or fatty oils from raw materials
  • C11B1/10—Production of fats or fatty oils from raw materials by extracting

Definitions

• This invention relates generally to processes for separating fat from tissue and to apparatus utilizing such processes. In particular, it relates to processes and apparatus for producing dried particles of defatted tissue.
• the water immiscible fat solvent generally used in the processes indicated above is a hydrocarbon solvent, particularly, ethylene dichloride.
• Such solvents must be removed from end products which are intended to be used for human .comsumption, and there is a growing belief that the presence of more than mere traces of such solvents in animal feed is objectionable.
• the removal of all traces of a fat solvent from the product is extremely difficult, and a better solution would appear to be the use of a solvent which is not considered to be injurious to the health of individuals. Traces of alcohol in a product are not considered to be injurious to the health of an individual consuming the product, or objectionable in animal feed. Further, alcohol can generally be removed by the application of heat to levels which are acceptable.
• the second process described in Fishery Byproducts Technology is attributed to A. Gutman and F.Vandenhenvel and uses isopropanol to extract fat and water from press-cake formed of fish offal.
• the isopropanol is used hot, drained from the cake after extraction, and the cake dried under vacuum.
• Isopropanol is recovered by distillation from the fish oil and reused in the process.
• Such plants have not proven to be commercially successful.
• An economic disadvantage of such plants is that the fish oil produced by the process is difficult to separate from the water removed from the fish and solvent.
• the azeotropic processes of Levin for defatting and dehydrating tissue particles achieve economical separation of the solvent fromthe water and oil, and retain the biological values in the tissue, but requires the use of a water immiscible solvent, and generally a toxic solvent.
• the foregoing objects of the invention are achieved by the process of comminuting the wet fat biological tissue and thereafter introducing the particles of tissue into a body of boiling water miscible solvent to form a slurry of solvent, particles and water, and maintaining the tissue in suspension in the slurry for a period of time sufficient to reduce the water content of the tissue to less than 10% by weight.
• the slurry is maintained under boiling conditions and the particles are maintained suspended in the slurry. Vapor of solvent and water is withdrawn from the slurry, thereby reducing the content of water in the tissue, and fresh solvent is introduced into the slurry to replace the solvent withdrawn in the vapor.
• the solvent water content of the added solvent by volume is maintained at least 95% alcohol during the period of time the tissue particles remain in the slurry.
• Figure 1 is a schematic drawing of a plant for commercial production of desiccated and defatted animal tissue according to the present inventio ;
• FIG. 2 is a fragmentary view of the high purity distillation system illustrated in Figure
• Figure 3 is a graph illustrating the results of processing two samples under identical conditions except for the water content of an isopropyl alcohol solvent.
• the process of the present invention is an improvement upon the processes described in the patent of Worsham and Levin, No. 2,503,312, and the patent of Levin, No. 2,503,313 referred to above in that a vessel partially filled with a fat solvent is employed, and comminuted particles of the tissue are introduced into a boiling mass of solvent to form a slurry of solvent, particles and water.
• the slurry only partially fills the vessel, and vapors in the form of an azeotrope of the solvent and water from the tissue particles develop in the space above the level of the slurry.
• the azeotropic vapors are withdrawn from the vessel, the solvent separated from the water, and the solvent returned to the vessel to replenish the level of slurry in the vessel. It is not necessary in the inventor's process to separate the water, fat and solvent from the separated liquid fraction, since the water and solvent are removed as vapor.
• the present invention differs materially from the process of Levin.
• the comminuted particles do not tend to coagulate in the solvent as in the Levin process.
• the alcohol solvent prevents coagulation.
• wet fat particles are heavier than the solvent, and sink in the body of solvent rather than float on the surface as in the case of an ethylene dichloride solvent.
• the present invention utilizes agitation or stirring to maximize the surface contact of the solvent and the particles.
• completion of dehydration is more readily determined by measurement of the concentration of isopropyl alcohol in the vapor removed from the interior of the vessel, or by determination of the specific gravity of the alcohol and water portion of the slurry of particles, alcohol and water in the vessel.
• the volumetric ratio of isopropyl alcohol to water in the solvent introduced into the vessel be at least 95% and preferably 99%.
• the slurry formed of solvent and particles becomes a slurry of solvent, water and particles.
• the removal of solvent and water vapor from the vessel gradually reduces the amount of water present in the vessel, that water being divided between bound water within the particles and the free water in solution with the isopropyl alcohol solvent.
• the free water in solution with the isopropyl alcohol be less than 8% by volume.
• Figure 3 is a graph comparing the desiccation and defatting of a laboratory sample of spleen according to the present invention.
• approximately 500 grams of raw spleen were ground into fine particles and mixed into a slurry in a beaker with approximately two liters of isopropyl alcohol solvent.
• the beaker was heated, and the vapor produced in the beaker withdrawn to a condenser.
• the condenser was provided with a water cooled jacket, and the specific gravity of the condensate was periodically measured to determine the percentage of isopropyl alcohol to water in the condensate.
• the sample When water is no longer present in large percentage in the condensate, the sample will be desiccated. In each case, the sample was placed under vacuum, and boiling occurred at approximately 33 degrees C.
• the lower curve of Figure 3 sets forth the results of processing a sample of spleen with 91% isopropyl alcohol.
• the percentage of isopropyl alcohol in the distillate from a 500 gram sample of spleen is set forth from the beginning of the process for a period of five hours, and shows that the percentage of isopropyl alcohol increased through this period from the first measurement of 85.6% IPA taken approximately 1/2 hour after beginning the process to a final reading of 89.02% taken 5 1/2 hours after the process began.
• the 500 grams of spleen yielded 98 grams of meat solids and contained a moisture content of 6.3% and quick fat of 2.44%. This product was achieved by utilizing three washes of
• the upper graph of Figure 3 illustrates the results of processing a second sample of spleen of approximately 505 grams under similar conditions but utilizing a solvent of 99% isopropyl alcohol to water by volume. Azeotroping was completed in three hours and forty minutes, and the percentage of isopropyl alcohol to water increased during this period from 86.3% taken approximately 1/2 hour after commencing the 0 process to 97.3% after three hours and forty minutes.
• FIG. 1 illustrates schematically a suitable
• the raw material is in the form of 0 small particles of raw fat biological tissue, and those particles and an alcohol solvent comprise the slurry 16.
• the alcohol solvent forms a solution with water extracted from the tissue particles.
• the boiling condition of the 5 . slurry 16 causes vapor to form in the portion of the vessel 10 above the level 14 of the slurry, this region being designated 20.
• the vapors formed by the slurry are in the form of an azeotrope of alcohol and water, and the vessel is provided with an upper port 22 for removal of the vapors.
• a stirring device 24 extends down in the slurry 16 and is driven by a motor 26 located externally of the vessel 10.
• the upper port 22 is connected to a condenser 28 which is provided with a cold water jacket not shown.
• the condenser has the function of converting the azeotropic vapors withdrawn from the vessel 10 through the upper port 22 to liquid form, and the condenser is connected to a used solvent tank 30.
• the used solvent tank 30 is connected to a high purity distillation system 32 which will be described in more detail hereinafter, and the distillation system 32 is effective to remove the water through an exit ⁇ port 34 and to provide solvent through a second exit port 36.
• the solvent exiting through the port 36 consists of alcohol with no more than 5% water by volume, and this exit port 36 is connected to a clean solvent reservoir 38.
• the clean solvent reservoir 38 is in turn connected to an upper inlet port 40 of the vessel 10 to replenish the solvent withdrawn from the slurry 16 by the vapors.
• the apparatus of Figure 1 is a batch system, and the apparatus thus far described is required for processing the raw material through the azeotropic cycle.
• the vessel 10 is provided with a lower opening 42, which has a valve not shown, and is connected to an extractor/desolventizer 44.
• the heater 18 is turned off, and the slurry 16 is dumped through the lower opening 42 into the extractor/desolventizer 44 through a produc opening 46.
• the extractor/desolventizer 44 also has an upper solvent opening 48, and this is connected to the clean solvent tank 38.
• the extractor/desolventizer also has a drain opening 50 for removal of liquids from the extractor/desolventizer, and a lower product opening 52 for removal of processed tissue solids. fter the slurry 16 is dumped into the extractor/desolventizer 44, the liquid portion thereof is drained through the drain 50 to the evaporator 54. Also, clean solvent is introduced through the solvent opening 48 to wash the solids from the slurry now located in the extractor/desolventizer 44. The solvent from the clean solvent tank 38 also is drained through the drain 50 and conducted to the evaporator 54. Heat is applied in the extractor/desolventizer 44 to dry the solid particles, and when the particles are dry they are removed through the finished product opening 52.
• the evaporator 54 receives from the extractor/desolventizer 44 a liquid flow of fat and solvent, the water having been removed as an azeotrope by the cooker 10. The evaporator applies heat to evaporate the solvent from the fat, and the evaporator has a drain 56 to remove the fat. Likewise, the evaporator 54 has an upper opening 58 through which solvent vapors flow to a condenser 60. The condenser 60 transforms the solvent vapors to liquid state, and the condenser 60 is connected to the clean solvent tank 38. PAGES 13 to 15 WERE NOT INCLUDED IN THE INTERNATIONAL APPLICATION ON FILING
• the solid particles of the sample in the extractor/desolventizer 44 were then washed with additional solvent and subjected to heat to drive off solvent in vapor form from the particles.
• the solvent vapors passed through the port 62 and were condensed in the condenser 64 and returned to the clean solvent tank 38.
• the dried solid particles were then removed through the finished product opening 52. Analysis of the particles indicated a yield of meal solids of 16.6% of the batch by weight, a fat recovery of 30.9% of the batch by weight, residual moisture of 2.1% and residual fat of 0.48%.
• the high purity distillation system 32 was actuated on completion of the foregoing sample to return the used solvent from the used solvent tank 30 to the clean solvent tank 38.
• the high purity system could also be operated during the azeotrope process.
• beef spleen, beef heart, and beef liver may be processed according to the foregoing example. 17
• the foregoing process is also suitable for processing whole ground fish or parts thereof, ground fowl, and all types of animal tissue.
• the present invention may be practiced with other water miscible liquid solvents that form an azeotrope with water.
• Low aliphatic alcohols such as isopropyl alcohol, ethyl alcohol and tertiary butyl alcohol are particularly suitable solvents.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Meat, Egg Or Seafood Products (AREA)

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• 1985
  • 1985-02-25 WO PCT/US1985/000294 patent/WO1985003721A1/en not_active Application Discontinuation
  • 1985-02-25 EP EP19850901268 patent/EP0174952A4/de not_active Withdrawn
  • 1985-02-25 CA CA000475027A patent/CA1255234A/en not_active Expired
  • 1985-10-23 DK DK486885A patent/DK486885A/da not_active Application Discontinuation

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