JP4632226B2 - Supercritical extraction method of powder components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for supercritical extraction of a powder component, and more specifically, a powder component that efficiently extracts a predetermined component from a powder without the powder being consolidated and consolidated by using a supercritical extractant. The present invention relates to a supercritical extraction method.
[0002]
[Prior art]
Conventionally, for example, a method described in Patent Document 1 is known as a method of extracting a predetermined component from egg yolk powder having compactness. This is a method for extracting cholesterol from egg yolk powder by bringing dried egg yolk powder, whole egg powder, milk powder and the like containing cholesterol into contact with high-pressure supercritical carbon dioxide in an extraction tank.
Here, in supplying carbon dioxide to the extraction tank, carbon dioxide is supplied at a constant flow rate while being pressurized, and the internal pressure of the extraction tank is increased from atmospheric pressure to a supercritical pressure in a short time.
[0003]
[Patent Document 1]
JP 59-135847 A
However, as in Patent Document 1, when carbon dioxide is supplied to the extraction tank at a constant flow rate, the flow rate of carbon dioxide is large when the internal pressure of the extraction tank is low. Therefore, the pressure loss increases, the consolidation of the egg yolk powder progresses and solidifies, and when it becomes a supercritical state in the extraction tank, the flow of supercritical carbon dioxide is inhibited, and extraction at a predetermined flow rate is difficult Thus, there is a possibility that the extraction time becomes long or the extraction cannot be performed. In addition, cracks occur in the packed bed of egg yolk powder, and supercritical carbon dioxide passes through the portion in a short path, thereby causing inconveniences such as a decrease in extraction efficiency.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a supercritical extraction method of powder that can efficiently extract a predetermined component from the powder without the powder being consolidated and consolidated.
[0006]
[Means for Solving the Problems]
The invention of claim 1 is a supercritical extraction method for a powder, wherein a predetermined component is extracted from a compacted powder filled in an extraction tank by using a supercritical extractant. In the supercritical extraction method of powder, the supply flow rate of the extractant is controlled so that the pressure difference per unit layer height in the extractant supply unit and the extractant discharge unit satisfies the following formula (1): is there.
M> ΔPa · L + ΔW · L (1)
Where M is the pressure tight load (kg / cm ² )
ΔPa is the pressure difference per unit layer height (kg / cm ² · m)
ΔW is the load due to its own weight per unit layer height (kg / cm ² · m)
L is the layer height (m).
[0007]
The supercritical extraction method of powder components refers to a method of extracting and separating useful or harmful components in powder using a supercritical extractant. Here, an extractant in a supercritical state having an extraction ability similar to that of a liquid and having a diffusion ability close to a gas is used. Therefore, the extraction efficiency is high, and the extraction capability can be easily controlled by appropriately selecting the temperature and pressure. Furthermore, the extractant as the extraction solvent can be easily and completely separated with less energy.
As the extractant, for example, carbon dioxide, methane, ethane, propane, nitrous oxide and the like can be employed.
The conditions for supercritical extraction are, when carbon dioxide is used as the extractant, usually the temperature is 31 ° C. or higher, preferably 31 to 100 ° C., and the pressure is 7.37 to 40 MPa, preferably 7.37 to 35 MPa. .
In the initial stage of extraction of the powder component, while monitoring the pressure difference before and after the packed bed in the extraction tank, the internal pressure of the extraction tank is required to be 10 minutes or more from atmospheric pressure to 0.98 Mpa, preferably 10 to 60 minutes. Boost the pressure. If it is less than 10 minutes, the flow rate of carbon dioxide becomes high, resulting in inconvenience that compaction occurs.
[0008]
Thereafter, while monitoring the pressure difference before and after the packed bed in the extraction tank, the supply rate of the extractant supplied to the extraction tank is gradually increased to finally set the pressure in a supercritical state.
Examples of powder that can be used include egg yolk powder, tea leaf powder, whole egg powder, and powdered milk.
The filling amount and filling height (layer height) of the powder in the extraction tank are appropriately selected according to the shape and internal volume of the extraction tank.
[0009]
The invention according to claim 2 is the supercritical extraction method according to claim 1, wherein the powder is egg yolk powder obtained by drying egg yolk.
As a method for drying the powder, a spray drying method, a freeze drying method, a normal heat drying method, or the like can be used, but a spray drying method in which the powder particles do not easily aggregate is preferable.
[0010]
A third aspect of the present invention is the supercritical extraction method according to the first or second aspect, wherein the extractant is carbon dioxide.
By using carbon dioxide as the extractant, it is advantageous in terms of safety and economy. Moreover, depending on the powder component used as a raw material, it is also preferable from the viewpoint of improving extraction efficiency that an appropriate solvent such as alcohol is used as an entrainer.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
According to this invention, when extracting the powder component, the supply flow rate of the extractant supplied to the extraction tank is lowered at the beginning of extraction when the internal pressure of the extraction tank is low, and then the pressure difference before and after the packed bed in the extraction tank is reduced. While monitoring, gradually increase the supply speed of the extract to be supplied to the extraction tank. As a result, the predetermined component can be efficiently extracted from the powder without the powder being consolidated and consolidated.
[0012]
Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 10 denotes a powder supercritical extraction apparatus to which a powder supercritical extraction method according to an embodiment of the present invention is applied. This supercritical extraction apparatus 10 mainly includes egg yolk powder (powder). ) Filled with an extraction tank 12, an extractant storage tank 13 for storing carbon dioxide (extractant) supplied to the extraction tank 12, and the extract storage tank 13 and the extraction tank 12 The extraction agent supply path 14 communicates.
[0013]
Hereinafter, these components will be described in detail.
The particle size of egg yolk powder is 10 to 100 μm. The extraction tank 12 has a cylindrical shape and is a tank (with an internal capacity of 4,000 cc) provided with a sealing lid on the upper end surface, and a jacket 15 is integrally formed from the outer peripheral surface to the bottom surface. Warm water as a heating medium is circulated through the jacket 15 from the lower supply port toward the upper discharge port. A discharge pipe 16 is formed at the lower end of the extraction tank 12 through the jacket 15. Through the discharge line 16, supercritical carbon dioxide extracted from the components of egg yolk powder is discharged out of the tank. A discharge valve V <b> 1 that adjusts the discharge amount of supercritical carbon dioxide after extraction is provided in an upstream portion of the discharge pipe 16.
[0014]
The inner cylinder 11 has a cylindrical shape, and an open lower end surface is covered with a porous plate 18. The inner cylinder 11 is housed in the middle part of the extraction tank 12 in the length direction. The inner volume of the inner cylinder 11 is 3,000 cc and is filled with 1.0 kg of egg yolk powder. As a result, a filling layer 19 of egg yolk powder having a height (filling height) of 0.4 m and a filling density of 0.3 g / cm ³ is formed in the inner space of the inner cylinder 11. Thus, by arranging the inner cylinder 11 at the center of the extraction tank 12, the extractant supply part (upper space) is in the upper part of the extraction tank 12, and the extractant discharge part is in the lower part of the extraction tank 12. (Lower space) is formed. A differential pressure gauge 21 for measuring a pressure difference is provided outside the extractant supply unit and the extractant discharge unit via a thin bypass pipe 20.
[0015]
The extract supply path 14 is a pipe channel that communicates the extract supply port of the extract storage tank 13 and the extract supply part of the extract tank 12, and sequentially supplies carbon dioxide from the upstream toward the downstream. A compressor 22 for increasing the pressure, a flow rate adjusting valve V2 for adjusting the supply amount of carbon dioxide by controlling the valve opening, an extractant heater (heater) 23 for increasing the temperature of carbon dioxide passing through the extractant supply path 14, A supply pressure gauge 24 that measures the pressure of carbon dioxide and a flow meter 25 that measures the flow rate of carbon dioxide are provided.
[0016]
Next, a supercritical extraction method of egg yolk powder to which the supercritical extraction apparatus 10 is applied will be described.
As shown in FIG. 1, first, the open / close lid at the top of the extraction tank 12 is opened, egg yolk powder is filled into the inner cylinder 11 by a predetermined amount, and then the open / close lid is closed to seal the extraction tank 12.
Then, the flow rate adjustment valve V2 is gradually opened while controlling the valve opening, and the carbon dioxide is gradually increased by the compressor 22 as necessary, and supplied into the extraction tank 12. Thereby, the pressure in the extraction tank 12 is increased from atmospheric pressure to 0.98 Mpa over 10 minutes (here, 20 minutes) (indicated by a solid line graph in FIG. 2). When a high-pressure cylinder of carbon dioxide is used as the extractant storage tank 13, pressure increase by the compressor 22 is not necessary, and supply is performed only by the cylinder pressure.
[0017]
Thereafter, the valve opening degree of the flow rate adjusting valve V2 and the pressure increase by the compressor 22 are further increased. Thereby, the pressure in the extraction tank 12 is increased from 0.98 Mpa to 3.92 Mpa over 10 minutes (here, 20 minutes). When a high-pressure cylinder of carbon dioxide is used as the extractant storage tank 13, pressure increase by the compressor 22 is not necessary, and supply is performed only by the cylinder pressure.
[0018]
Thereafter, the valve opening degree of the flow rate adjusting valve V2 and the pressure increase by the compressor 22 are continued to increase the pressure. Moreover, by supplying a heating medium to the jacket 15 and heating the extraction tank 12, the internal pressure of the extraction tank 12 is increased from 3.92 Mpa to a supercritical pressure, and the pressure is further increased by increasing the pressure to 29.4 Mpa. The pressure is increased over 30 minutes (here 50 minutes).
Thereafter, the discharge valve V1 is opened, and the fat component is extracted from the egg yolk powder with supercritical carbon dioxide while maintaining the supercritical state at this pressure for 1 hour or longer (here, 4 hours).
The supercritical carbon dioxide containing the fat and oil component discharged through the discharge path 16 is supplied to an extract separation and recovery device (not shown). With this apparatus, supercritical carbon dioxide is separated and the oil and fat component is recovered.
[0019]
During the pressurization, the pressure difference between the front and back of the packed bed 19 of egg yolk powder filled in the extraction tank 12 is measured by the differential pressure gauge 21. The pressure difference is always maintained so as to satisfy the equation of M> ΔPa · L + ΔW · L, and the supply amount of carbon dioxide is controlled. Here, M is a pressure tight load (kg / cm 2
), ΔPa is a value obtained from the pressure difference ΔP between the extractant supply part and the extractant discharge part and the layer height, the pressure difference per unit layer height (kg / cm ² · m) when averaged , ΔW is The load (kg / cm ² · m) due to its own weight per unit layer height, L is the layer height (m). Further, the degree of pressure increase of carbon dioxide by the compressor 22 is adjusted based on the measured value of the supply pressure gauge 24. On the other hand, based on the values of the flow meter 25 and the differential pressure gauge 21, the valve opening degree of the flow rate adjustment valve V2 is automatically adjusted.
Note that M is a value of an inflection point at which the load is gradually increased during the pressure density measurement test and the compressibility rapidly increases, and is measured in advance for the egg yolk powder. ΔPa is a value obtained from ΔP obtained by the differential pressure gauge 21 and the bed height. ΔW is a value determined by the weight and layer height of the egg yolk powder filled in the extraction tank 12. Furthermore, L is the value of the layer height of the egg yolk powder when it is first filled.
[0020]
The ΔP and the flow rate of supercritical carbon dioxide have the following relationship. Therefore, the supply flow rate of carbon dioxide is determined by monitoring ΔP so as to satisfy the following formula (2).
[0021]
ΔP = f _c · {L · 6 (1−ε) / ε · D _p } · {ρ (U _f / ε) ² / 2g _c } (2)
[0022]
ΔP is determined by the differential pressure gauge 21 (kg / cm ² ). f _c is the coefficient of friction is determined by the carbon dioxide and Reynolds number. L is the layer height (m) of the egg yolk powder when the extraction tank 12 is initially filled. ε is the porosity due to filling with egg yolk powder. D _p is the particle size (m) of the processed product. ρ is the density of carbon dioxide (kg / cm ³ ), and U _f is the apparent flow rate of carbon dioxide (m / sec). This U _f is also obtained by Q (m ³ / hr) / inner cylinder cross-sectional area (m ² ) · 3,600. Q is determined by an anemometer (m ³ / hr). g _c is the acceleration of gravity (kg / sec ² ).
[0023]
Where f _c is the number of ray nozzles (Rec)
For Rec = ρ · Dp · uf / {6 (1-ε) μ}, it is shown as follows.
Here, μ is the viscosity coefficient (kg / m · sec) of the extractant.
Re <1: fc = 9.45 / Re
Re = 1 to 5: fc = 0.734 + 8.84 / Re
Re = 5 to 100: fc = {9.45 + 0.944 (Re−0.833) ^0.88 } / Re.
Thus, at the start of extraction of the oil and fat component of egg yolk powder, the flow rate of carbon dioxide into the extraction tank 12 is kept low, and then the supply rate of carbon dioxide is gradually increased according to the density of carbon dioxide in the extraction tank 12. To increase. As a result, the fat component can be efficiently extracted from the egg yolk powder without the egg yolk powder being consolidated and consolidated.
In FIG. 2, the alternate long and two short dashes curve graph shows another implementation in which the internal pressure of the extraction layer 12 is gradually increased in the initial stage of extraction, and the internal pressure is continuously increased by drawing a steep curve from about 3.92 Mpa. An example is shown. Other configurations, operations, and effects are the same as those of the solid line graph shown in FIG.
[0024]
【The invention's effect】
According to the powder supercritical extraction method of the present invention, at the start of extraction of the powder component, the supply flow rate of the extractant into the extraction tank is kept low, and then, depending on the density of the extractant in the extraction tank. Since the supply speed of the extractant is gradually increased, the predetermined component can be efficiently extracted from the powder without the powder being consolidated and consolidated.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a powder supercritical extraction apparatus to which a powder supercritical extraction method according to an embodiment of the present invention is applied.
FIG. 2 is an operation pattern of a supercritical extraction method for powder according to one embodiment of the present invention.
[Explanation of symbols]
10 Supercritical extraction equipment for powder components 12 Extraction tank

Claims (3)

1. In the supercritical extraction method of the powder component using the carbon dioxide in the supercritical state as the extractant, the predetermined component is extracted from the egg yolk powder obtained by drying the yolk filled in the extraction tank.
   The supply flow rate of the extractant is controlled so that the pressure difference per unit layer height in the extractant supply part and the extractant discharge part of the extraction tank satisfies the following formula (1) :
   A supercritical extraction method for powder components , wherein the pressure in the extraction tank is increased from atmospheric pressure to 0.98 Mpa over 10 minutes .
   M> ΔPa · L + ΔW · L (1)
   Here, M is a pressure tight load (kg / cm ² ), which is a value of an inflection point at which the load is gradually increased and the compressibility rapidly increases during the pressure density measurement test, Things to measure in advance:
   ΔPa is a value obtained from the pressure difference ΔP between the extractant supply part and the extractant discharge part and the layer height, and the pressure difference per unit layer height (kg / cm ² · m) when averaged:
   ΔW is the load due to its own weight per unit layer height (kg / cm ² · m):
   L is the bed height (m).
2. The method for supercritical extraction of powder components according to claim 1, wherein the pressure in the extraction tank is increased from 0.98 Mpa to 3.92 Mpa over 10 minutes.
3. The method of supercritical extraction of a powder component according to claim 1 or 2, wherein the pressure in the extraction tank is increased from 3.92 Mpa to 29.4 Mpa over 30 minutes.

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