JPH0798956B2 - Dry separation method of fats and oils - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technique for separating fats and oils by a difference in melting temperature of constituent fats and oils components.

[Conventional technology]

(Background) Liquid oils and fats, liquid waxes, and other oily substances composed of a mixture of several similar components can be separated by the melting temperature difference of each component by separating organic solvents such as acetone or hexane, and by using a surfactant. Known methods include detergent sorting, wintering, and sweating.

Among these methods, the method is capable of precise separation, but on the other hand, it has the drawback of being dangerous and costly because it works with a flammable solvent. The method is not only inferior in terms of fractionation accuracy and product quality, but it is troublesome to separate the oil / fat from the surfactant solution and treat the waste water. In the method (1), the equipment for the crystallization tank is expensive, and the productivity, the separation efficiency, and the quality of the product are further inferior to the former two. This method is applicable to dewaxing because the applicable raw material properties are limited, but it is not suitable for separating fats and oils.

(Problems of the Prior Art) Conventionally, in the above method, a method in which a vertical crystallization tank having a stirrer is used and the water temperature of the refrigerant is gradually reduced to gradually crystallize is widely used. In this method, after the completion of crystallization, a slurry-like crystal is extracted from the bottom of the tank, and is pressed and filtered by a belt press, a filter press, or the like in a later step to separate the crystal side and the liquid side. Generally, the above operation is possible under the condition that the crystal ratio is 10 to 30% by weight or less and the crystal ratio is relatively low, but when the crystal ratio is 30% or more, especially 40 to 70% by weight, ,
Unless crystallized under stirring, the crystal mass loses fluidity at all and cannot be discharged from the crystallization tank.

Therefore, in order to obtain a high crystallization rate, it is necessary to crystallize while gently stirring, but when this is done, the obtained crystals are likely to enclose the liquid part, and the crystal quality is significantly deteriorated. Moreover, since the stirring is performed, a powerful stirring device is required, which increases the equipment cost.

For the above reasons, it is the current situation that the existing method is operated under the operating conditions of a relatively low crystal ratio of 10 to 30% by weight, but the low melting point component should be sufficiently concentrated due to the low crystal ratio. Therefore, there is a drawback that the quality of the product is inferior.

[Problems to be Solved by the Invention]

In view of the above circumstances, the problem to be solved by the present invention is to dry-separate an oil or fat that forms an oil lump with a high degree of crystallinity at the end of crystallization and having a high degree of crystallinity (no or almost no self-fluidity). Is to give industrial potential to.

[Means for Solving the Problems]

(Outline) As a result of various studies on the means for imparting fluidity to the oil lump, the inventors have found that, particularly in non-lauric fats and oils such as palm oil, an oil lump with a high crystal ratio once solidified by crystallization. Surprisingly, it was found that by crushing and kneading by adding appropriate shearing force or physical vibration to the slurry, it was found that the slurry changed to a creamy self-fluidizing slurry, and , And found that the filtration characteristics were significantly superior to the untreated crystal mass.

The dry fractionation method of an oil and fat substance according to the present invention is based on the above findings, in a method of cooling and solidifying a non-lauric oil and fat into a solid portion and a liquid portion, a device having a cooling function in advance. After cooling the oil and fat and crystallizing it until the crystal ratio after pressing reaches 30 to 60% by weight, this is crushed by a device equipped with a physical kneading or crushing mechanism without adding a liquid substance. Fluidized, and then filtered or squeezed to separate into a crystal part and a liquid part, a dry fractionation method of fats and oils (non-lauric fats and oils), as non-lauric fats and oils to be the subject of the present invention, C ₁₂ Fats and oils substantially not containing saturated fatty acid residues, specifically, animal fats and oils such as beef tallow, lard, palm oil, soybean oil, rapeseed oil, shea butter, vegetable fats such as monkey fat, esters Replacement oil or hardened oil thereof or Fractionated hardened oil and the like can be mentioned, but of course, the oils and fats are not limited to the exemplified fats and oils.

(Cooling) There is no particular limitation on the cooling means in the present invention, but crystals having more excellent crushing effect and squeezing performance are densely grown into needle-like or dendritic form and form small lumps having a size of several tens of μ or more. It is important that it is formed, usually under fairly mild cooling conditions,
In addition, it is obtained by crystallization under a stationary state. For example, in the case of palm oil, once melted at a temperature of about 50 to 60 ° C, it is gently cooled and crystallized under air cooling or water cooling at 10 to 20 ° C to form a dendritic sphere with a diameter of about 10 to 100μ. Crystals precipitate. This crystal mass is easily fluidized by crushing,
The squeezing performance is significantly improved. However, these conditions may vary considerably depending on the type of target fat and oil, the size of the cooling rate, and the desired properties of the fractionated fat. When water is used as the refrigerant, it is necessary to sufficiently reduce the cooling rate before crystal precipitation. Therefore, delicate consideration is required in adjusting the water temperature.

The crystal lump obtained as described above is a microscopically non-uniform lump in which an amorphous low melting point component is mixed between the high melting point crystals.

(Crushing) Crushing is performed by using a low rotation type mixer, auger, kneader, etc., which physically disperses aggregates of needle-like or dendrite-like crystals and has a crystal structure. It should not destroy itself. The oil lumps are divided and crushed by the mechanical action such as shearing, impact, and tensile force inside these machines, and the small oil lumps mainly composed of high melting point oils and fats are partly melted liquid low melting point. Since it becomes a slurry that is dispersed in oil and fat, it can be transported as it is by a pump.

If this step is omitted, pumping cannot be performed as described above in a state where the crystal ratio is high, and even if the cake is directly subjected to the next squeezing step, desorption of the liquid part from the cake is insufficient. Therefore, the iodine value of the solid part increases while the iodine value of the liquid part is low.

(Squeezing) The above-mentioned non-lauric oil and fat slurry is then filtered or squeezed to be separated into a high melting point solid fat and a low melting point liquid fat. Any method can be adopted as a means for filtering or squeezing, and an appropriate method is selected depending on the quality of the product to be obtained and the raw material oil and fat.

[Action]

With reference to the attached FIG. 1 which schematically illustrates the principle of the present invention, a high melting point portion (a portion rich in high melting point molecular species) H in fats and oils gradually grows in a dendritic form upon cooling, and a low melting point portion ( A small oil lump P enclosing a portion L rich in low-melting molecular species is formed, and a large number of such small oil lumps P form relatively weak bonds with each other to form a large oil lump (FIG. A). When a shearing force is applied in this state, the weak bond between the small oil lumps is broken, the large oil lump decomposes into the unit small oil lumps P, and the low melting point L trapped between the small oil lumps is first released. For this reason, the small oil lump P loses the cement for joining and becomes fluid (see FIG. B).

Next, when this is filtered or squeezed, the low melting point L is pushed out of the oil lump, separating the crystalline high melting point and the liquid low melting point, and the latter is discharged to the outside of the filtration chamber through the filter. Will be performed (C in the same figure).

According to the inventor's knowledge, the separation phenomenon between the high melting point portion and the low melting point portion due to the above crushing is unique to non-lauric oil and fat, and even when lauric oil and fat such as palm kernel oil is crushed, It does not become a slurry state. It is unclear why this is due to any reason, but the findings of the inventor are
An important characteristic for the successful dry fractionation of this oil / fat is discovered.

In short, according to the present invention, even a coagulated fat or oil with a high crystal ratio can obtain a fluid state to the extent that it can be pumped by crushing. Nor. Therefore, not only the processing ability of the crystallization and filtration device is improved, but also the filtration efficiency is significantly improved.

〔Example〕

Hereinafter, embodiments of the invention will be described with reference to examples, but the exemplification is merely for explanation, and does not directly relate to the interpretation of the technical scope of the invention.

Example 1 and Comparative Example 1 After cooling the liquid part of palm oil under the cooling conditions shown in Table 1 below,
With or without crushing, a small filter press with a frame thickness of 20 mm was pressed and squeezed under a condition of 28 kg / cm ² for 1 hour to divide into a solid part and a liquid part. The results are also shown in Table 1 below.

As can be seen from the above table, those that have undergone crushing and kneading are higher than those that have not undergone this step, despite the fact that the iodine value of the liquid part is higher in the state where crystallization is more advanced, Both the yield on the solid side and the iodine value after pressing are remarkably low, and it is clear that the pressing can be performed more effectively.

Example 2 A palm oil liquid part similar to that of Example 1 was cooled and solidified at 15 ° C. The oil lump was crushed as it is or after crushing, followed by squeezing with a filter press similar to that of the same example, and tracing the filtration rate with time. did. The results are shown in FIG. As is clear from the figure, the filtration rate in the case of crushing is about double that in the case of uncrushing.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention can contribute to the improvement of the oil / fat separation technology and the reduction of the separation cost by providing the dry separation method for the substance on oil having excellent workability and separation efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for schematically explaining the principle of the present invention, and FIG. 2 is a graph showing the effect on filtration performance.

Claims (2)

[Claims] 1. A method for cooling and solidifying non-lauric oil and fat to separate it into a solid portion and a liquid portion, wherein the oil and fat is cooled in advance by an apparatus having a cooling function, and the crystal ratio after pressing is 30.
After crystallizing until it reaches ~ 60% by weight, it is crushed and fluidized by a device equipped with a physical kneading or crushing mechanism without adding a liquid substance, and then filtered or pressed. A dry fractionation method for fats and oils, characterized by fractionating into a crystal part and a liquid part. 2. The fractionation method according to claim 1, wherein the fats and oils are cooled slowly by air or water cooling to produce needle-like or dendrite-like crystals.