JPH02102495A - centrifugal extractor - Google Patents

Abstract

PURPOSE:To efficiently execute the material transfer in liquid, i.e. extraction by finely disintegrating liquid particles by mechanical shearing. CONSTITUTION:The nitric acid soln. and org. solvent liquid supplied from supply ports 38, 29 enter a liquid pool 40 and are stirred and mixed by a stirring body 23 when a rotating body 22 rotates at a prescribed rotating speed. The two liquids receive mechanical shearing forces by many rotating fine columnar projections 25. Since the projections 25 are disposed zigzag, the liquid particles are finely disintegrated and emulsified to form an emulsion. The liquid mixed in such a manner is discharged into the rotating body 22 by vanes 26 for a pump and are separated by the light liquid and the heavy liquid by the effect of sp. gr. difference of the materials in the liquid mixture and the centrifugal force. These liquids enter liquid receivers 36, 37 corresponding respectively thereto via gates 27, 28 and discharge ports 34, 35 and are recovered to the outside part. Since the liquid mixture is formed to the emulsion state in such a manner, the liquid drop sizes of the liquid mixture are extremely reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a centrifugal extractor, and particularly to a centrifugal extractor suitable for use in the reprocessing of spent nuclear fuel.

[Conventional technology]

A centrifugal extractor for nuclear fuel reprocessing brings a nitric acid solution in which spent nuclear fuel is dissolved into contact with an organic solvent by stirring and mixing, and then, by the action of centrifugal force, a light liquid with a low specific gravity containing U and Pu is extracted. It is separated into a heavy liquid with high specific gravity containing fission products.

A conventional example is the structure shown in FIGS. 11 and 12, as described in Japanese Unexamined Patent Publication No. 57-18042.

In the figure, a cylindrical rotating body 1 is rotated by a motor (not shown) in the direction of arrow B in FIG. 12 at a predetermined number of rotations. On the other hand, the nitric acid solution and the organic solvent are supplied to a liquid reservoir 4 through respective supply ports 2 and 3, and a pump 5 having a small diameter opening at the lower end of the liquid reservoir 4 is fixed to the lower shaft 9 of the central shaft 6 of the rotating body 1. It is supplied into the rotating body 1 from the central opening 12 of the lower end plate 11 by a centrifugal pump formed by an impeller 7 and a cylinder 10 fixed to a casing 8 .

Another function of the pump 5 is to form a stirring body that stirs and mixes the nitric acid solution and organic solvent liquid entering the liquid reservoir 4, and brings the two liquids into contact with each other. Thereby, the target substances U and Pu are transferred and extracted by utilizing the fact that the distribution coefficients of U, Pu and fission products vary depending on the nitric acid concentration.

The mixed liquid supplied to the rotating body 1 is separated into a light liquid and a heavy liquid by centrifugal force, passes over weirs 13 and 14 corresponding to the heavy liquid, and is further recovered through extraction holes 15 and 16. In addition,
Reference numerals 17 and 18 are rotating partition plates and disk-shaped deflection plates that are radially attached to the central shaft 6, and serve to promote separation of liquid.

[Problem to be solved by the invention]

A feature of the above conventional structure is that when the rotating body 1 is extracted upward, there is no stationary part that prevents the rotating body 1 from being extracted, so it can be used for maintenance inspections and troubleshooting of equipment in environments with high radioactivity levels. The workability is good. However, on the other hand, the pump 5 has paddle-shaped or propeller-shaped blades, which have both the pumping action of pumping up the liquid and the action of stirring and mixing two liquids, so that the entire liquid is It rotates widely, the degree of mixing of the two liquids is rough, and the droplet diameter is large. Therefore, there is a problem that the contact area between the organic solvent and the nitric acid solution is small, and the extraction efficiency and speed are low.

An object of the present invention is to provide a centrifugal extractor for nuclear fuel reprocessing that has small droplets and a stirring body that can stir and mix.

[Means to solve the problem]

The above objective is achieved by fragmenting the liquid particles by mechanical shearing.

[Effect]

Therefore, the blades that stir the liquid are replaced with many thin rods. By passing these many thin rods through the liquid, the liquid particles are sufficiently divided and emulsified to form an emulsion. Therefore, the contact area between the organic solvent and the nitric acid solution can be increased.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 21 is a rotating shaft that is rotationally driven by a motor (not shown), and 22 is a cylindrical rotating body fixed to the rotating shaft 21. A stirring body 23 is attached to the lower end of the rotating shaft 21, and a pump blade 26 is attached to the upper part of the stirring body 23. The stirring body 23 consists of a rotating disk 24 and a large number of thin columnar projections 25 fixed thereto.
are arranged in a zigzag manner in the circumferential direction of the disk 24. There is a light liquid weir 2 on the inside upper part of the rotating body 22.
7 and a heavy liquid weir 28 are provided, a rotary partition plate 29 for preventing rotational slip of the liquid is attached below the weir 28, and a deflection plate 30 for changing the direction of flow is attached below the partition plate 29. Reference numeral 31 denotes a non-rotating thin rectangular baffle plate arranged radially to prevent the swirling flow of liquid in contact with the lower end plate 32 of the rotating body 22, and is installed on the partition plate 34 at the bottom of the casing 33. . Near the weirs 27 and 28 on the upper part of the rotating body 22, liquid receivers 36 and 37 for light liquid and heavy liquid are provided in the casing 33, facing the separated light liquid and heavy liquid extraction ports 34 and 35. is placed above. On the other hand, at the lower end of the casing 33 there are supply ports 38 and 39 for nitric acid solution and organic solvent, which communicate with the liquid ffl 40 above.

In this configuration, when the rotating body 22 rotates at a predetermined rotation speed, the nitric acid solution and the organic solvent solution supplied from the supply ports 38 and 39 enter the liquid reservoir 40 and are stirred and mixed by the stirring body 23. In this case, both liquids are subjected to mechanical shearing force by a large number of rotating thin columnar protrusions 25, and since the columnar protrusions 25 are arranged in a zigzag pattern, the liquid particles are fragmented and emulsified to form an emulsion. Become. In this way, the well-mixed liquid is transferred to the rotating body by the pump vane 26.
2, and is separated into a light liquid and a heavy liquid by the difference in specific gravity of the substances in the mixed liquid and the action of centrifugal force.

They enter the corresponding liquid receivers 36 and 37 via the weirs 27 and 28 and the extraction ports 34 and 35, respectively, and are recovered to the outside.

According to this embodiment, since the mixed liquid can be made into an emulsion, there is an effect that the droplet diameter of the mixed liquid can be made very small. Note that the same effect can be obtained whether the columnar projection 25 is upright or curved.

3 and 4 show a second embodiment of the present invention, and the difference from FIGS. 1 and 2 is that the rotating disk 41 of the stirring body 43 has a width wider than the thickness of the baffle plate 31. slit 42
The reason is that the same number of baffle plates 31 are provided. According to this embodiment, the inner diameter of the baffle plate 31 is the same as that of the rotating disk 4.
If the outer diameter is smaller than the outer diameter of the rotating body 22 and the rotating shaft 21,
When pulling out upward from the rotating body 2, the angle of the slit 42 of the stirring body 43 matches the angle of the baffle plate 31.
By turning 2 to match, there is an effect that the rotating part can be taken out upward at once without being obstructed by stationary parts such as the baffle plate 31.

FIG. 5 shows a third other embodiment of the present invention, which differs from FIGS. 1 and 2 in that the rotating disk 58 of the stirring body 59 has an outer diameter that is smaller than that of the non-rotating portion of the baffle plate 31 or the partition plate. This is because the diameter is smaller than the inner diameter of 34mm. According to this embodiment, when the rotating portion including the stirring body 59 and the rotating body 22 is extracted upward from the casing 33, the rotating portion is removed from the baffle plate 3.
There is an effect that the rotating part can be pulled out upward at once without being hindered by stationary parts such as 1 and the partition plate 34.

FIG. 6 shows a fourth embodiment of the present invention, which differs from FIGS. 1 and 2 in the top of the rotating disk 47.

There are also many columnar projections 44, 45 and 4 on the lower surface and outer peripheral side.
6 was planted to constitute the stirring body 48. According to this embodiment, since the stirring section is formed on multiple surfaces, it is possible to apply mechanical shearing force to a large amount of liquid at the same time to fragment the liquid particles.

FIGS. 7 and 8 show a fifth embodiment of the present invention, and the difference from FIGS. 1 and 2 is that an aggregate made of thin wire is passed between two points of a rotating disk 49. Provide multiple 50,
The reason is that the stirring body 51 is formed in such a manner that they do not intersect with each other.

According to this embodiment, by rotating the framework 50 in the liquid, mechanical shearing force can be applied to the liquid so as to subdivide the liquid particles, so there is an effect that the mixed liquid can be made into an emulsion. Note that the effect of the frame 50 is the same whether the aggregate is spread in a curved manner or in a combination of a straight line and a right angle.

9 and 10 show a sixth embodiment of the present invention, and the difference from FIGS. 7 and 8 is that a plurality of aggregates made of thin wires are passed between two points of a rotating disk 52. individual skeletons 53-5
6 are crossed with each other to form a stirring body 57.

According to this embodiment, mechanical shearing force can be applied to the liquid by the frameworks 53 to 56 to subdivide the liquid particles in a more complicated manner, so that it is possible to generate a liquid mixture consisting of smaller droplets. can.

In addition, since the rotating part can be extracted upward at once without being obstructed by the non-rotating part, the centrifugal extractor can be easily maintained and repaired in environments with high radioactivity levels.

〔Effect of the invention〕

According to the present invention, mass transfer within a liquid, that is, extraction, can be performed efficiently and at high speed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a centrifugal extractor according to an embodiment of the present invention, FIG. 2 is a view taken in the direction of the ■ arrow in FIG. 4 is a view in the direction of the ■ arrow in FIG. 3, FIG. 5 is a vertical cross-sectional view of a main part of a third embodiment of the present invention, and FIG. 6 is a vertical cross-sectional view of a main part of a fourth embodiment of the present invention. FIG. 7 is a vertical cross-sectional view of a main part of a fifth embodiment of the present invention, FIG. 8 is a view taken in the direction of the ■ arrow in FIG. 7, and FIG. 10 is a view in the direction of the X arrow in FIG. 9, FIG. 11 is a longitudinal sectional view of a conventional centrifugal extractor, and FIG. 12 is a view in the direction of the ■ arrow in FIG. 22... Rotating body, 23... Stirring body, 24... Rotating disk, 25... Pin, 26... Pump vane, 31
...Baffle plate, 33...Casing, 34...
Partition board. Figure Figure Figure 7 j Section 8 Figure 6 j Cause 9

Claims (1)

[Scope of Claims] 1. A rotating cylindrical body, a rotating shaft located at the center of the rotating cylindrical body and rotating at the same time, and provided below a central opening of a lower end plate of the rotating cylindrical body, and a stirring body for stirring the liquid attached to the lower end of the rotating shaft, a non-rotating baffle plate made of rectangular plates arranged radially facing the lower end plate with a gap, and housing these. 1. A centrifugal extractor comprising: a casing, wherein the stirring body is composed of a large number of thin wires. 2. The centrifugal extractor according to claim 1, wherein the agitating body is formed by a rotating disk with a large number of columnar protrusions erected thereon. 3. The centrifugal extractor according to claim 1, wherein the stirring body is formed by planting columnar projections on the upper, lower and outer peripheral surfaces of a rotating disk. 4. The centrifugal extractor according to claim 1, wherein the agitating body is formed of a plurality of frameworks made of small-diameter aggregates distributed at two points on a rotating disk. 5. In claim 1, when the inner diameter of the baffle plate is smaller than the outer diameter of the rotating disk of the agitator, a slit slightly wider than the thickness of the baffle plate is rotated by the number of baffle plates. A centrifugal extractor characterized by being installed on a disc.