JPS6238002B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a centrifugal extractor.

The centrifugal extractor used in the liquid-liquid extraction process is
It is configured as shown in the figure. That is, in FIG. 1, there is a rotating cylinder 2 inside the cylindrical casing 1.
are arranged concentrically, and a T-shaped liquid supply pipe 3 is provided at the bottom of the casing 1, through which heavy liquid is supplied from one end and light liquid is supplied from the other end. Further, a suction vane 4 is provided in the casing 1, extending into the opening of the T-shaped liquid supply pipe 3 to the casing 1, and fixed concentrically to the bottom surface of the rotating cylinder 2. Further, near the upper end of the casing 1, there are provided a weir 5 for separating light liquids which terminates near the circumferential surface of the shaft 2a of the rotating cylinder 2, and a weir 6 for separating heavy liquids which terminates radially outward from the weir 5. . In addition, 7 is a light liquid extraction tube, 8
indicates a heavy liquid extraction tube, and 9 and 10 indicate receivers, respectively.

In the conventional extractor configured as described above, the light liquid and heavy liquid flowing from both ends of the T-shaped liquid supply pipe 3 are mixed by the suction blade 4 that rotates together with the rotating cylinder 2, and while the extraction progresses, the light liquid and heavy liquid that flow in from both ends of the T-shaped liquid supply pipe 3 are The two liquids are separated by the difference in specific gravity, and the light liquid flows from the weir 5 and the heavy liquid flows from the weir 6 into the receptors 9 and 10, respectively.

In the nuclear fuel reprocessing process, spent nuclear fuel is treated with nitric acid solution (uranium, plutonium, and other FPs).
uranium and plutonium are extracted from organic solvents (including uranium and plutonium) in organic solvents, and a centrifugal extractor such as the one illustrated in FIG. 1 is used for the extraction. In the extraction process for this reprocessing, multiple centrifugal extractors are connected to increase extraction efficiency.
It is common to have heavy liquid (nuclear fuel nitric acid solution) and light liquid (organic solvent) flow in countercurrent flow.
The liquid pumped up by the pumping action of one centrifugal extractor flows through the liquid supply section of the next stage centrifugal extractor until it reaches the suction blade due to the difference in head height. In conventional centrifugal extractors, the heavy liquid has a higher specific gravity than the light liquid, so it accumulates at the bottom of the T-shaped liquid supply pipe 3 and narrows the path for the liquid flowing in from the previous centrifugal extractor. Furthermore, since the viscosity of light liquids is generally higher than that of heavy liquids, it becomes difficult for light liquids to flow through the narrow passages as described above, resulting in overflow of light liquids in the centrifugal extractor in the previous stage, or in the separation chamber. There is a risk that the balance between the two liquids will be disrupted and the extraction process will not be carried out smoothly.

The present invention has been made based on the above-mentioned circumstances, and provides a centrifugal extractor that is free from the risk of narrowing the flow path for light liquid due to heavy liquid in the liquid supply pipe.

The invention will be explained in detail below with reference to the drawings. In FIG. 2, inside the cylindrical casing 11,
A rotating cylinder 12 is housed concentrically. A shaft 13 a of a motor 13 passing through the upper end wall of the casing 11 is connected to the center of the upper end plate of the rotating cylinder 12 .

A liquid supply chamber 16 is provided in the lower part of the casing 11 via a partition wall 15 having a guide tube 14 in the center which will be described later. The guide cylinder 14 has its upper end opening engaged with the center of the bottom surface of the rotary cylinder 12, and its lower end opening whose diameter decreases downward projects into the liquid supply chamber 16.

Inside the rotating cylinder 12, there are four baffle plates 17 arranged circumferentially at 90° intervals, a lower flange 19 that terminates near the inner circumference of the rotating cylinder 12, and forms a weir 18 for heavy liquid, and a lower flange 19 in its radial direction. A cylinder 21 that forms a weir 20 for light liquid inside, and an upper flange 22 that extends from the upper end of the cylinder 21 to the inner circumference of the rotating cylinder 12.
A weir component 23 is provided. Also,
A circular baffle plate 17a having a plurality of openings 17b around the periphery is provided at the lower part of the rotating cylinder 12.

On the side wall of the rotating cylinder 12, a heavy liquid outlet 24 is provided between the upper and lower flanges, and a light liquid outlet 25 is provided between the upper flange and the upper end plate of the rotating cylinder.

Further, a suction blade 26 located near the lower end of the guide cylinder 14 is fixed to the center of the lower end plate of the rotating cylinder 12.

Furthermore, a guide tube 1 is provided at the center of the bottom surface of the liquid supply chamber 16.
A heavy liquid supply pipe 27 is provided which terminates close to the four openings, and a light liquid supply pipe 28 is provided which terminates above the heavy liquid supply pipe 27 at an eccentric position.

In FIG. 2, reference numeral 29 indicates a heavy liquid receiver, 29a a discharge pipe, 30 a light liquid receiver, and 30a a discharge pipe.

In the centrifugal extractor of the present invention having the above configuration, a heavy liquid 31 and a light liquid 32 are supplied from the respective supply pipes 27 and 28.
forms two layers with an interface 33 in between. Therefore, the position of the lower end of the guide cylinder 14 and the position of the suction vane 26 are determined as follows. That is, the suction vane 26 is positioned at the surface of both liquids forming two layers, and the lower end of the guide tube 14 is positioned at the interface 33. Ultimately, the position of the suction vane 26 is determined by the sum of the flow rates of the light and heavy liquids, and the position of the lower end of the guide tube 14 is determined by the flow rate ratio of the two liquids.

The operation of the centrifugal extractor of the present invention will be explained below. The light liquid 32 and the heavy liquid 31 are mixed and stirred by the suction vane 26 while rising inside the guide cylinder 14 and passing through the opening 1.
7b and flows into the separation chamber 12a of the rotating cylinder 12. In the meantime, extraction is performed. Separation chamber 12
In a, the heavy liquid collects near the inner peripheral surface of the rotating cylinder 12, and the light liquid collects near the center, and the two liquids are separated.The heavy liquid enters the receiver 29 through the weir 18 and is discharged into the discharge pipe 29.
a, the light fluid also passes through the cough 20 to the receptor 30
The water enters and flows out from the discharge pipe 30a.

When centrifugal extractors are used in multiple stages and both liquids flow countercurrently, such as in the extraction process during nuclear fuel reprocessing, the heavy liquid discharge pipe 29a is connected to the heavy liquid supply pipe of the previous stage centrifugal extractor, and the light liquid The discharge pipes 30a are respectively connected to the light liquid supply pipes of the subsequent centrifugal extractor.

In the centrifugal extractor of the present invention having the above configuration, the lower end opening of the guide cylinder 14 is located at the interface 33, and the light liquid and heavy liquid are injected into the liquid supply chamber 16 through separate supply pipes 28 and 27. Since the openings of each supply pipe are located within the respective phases, there is no risk of heavy liquid entering the light liquid supply pipe and constricting the flow path of the light liquid. Therefore, there is no risk of an overflow of the light liquid in the centrifugal extractor at the front stage or an imbalance in the flow rates of both the heavy and light liquids. Further, since the heavy liquid supply pipe 27 is terminated near the opening of the guide cylinder 14 and is opposed to the suction vane 26, the heavy liquid can flow easily, and the resistance to the flow of the light liquid is also reduced.

FIG. 3 shows another embodiment of the invention. In this embodiment, a heavy liquid supply pipe 27 and a light liquid supply pipe 28 are passed through the side wall of the liquid supply chamber 16, and at the end of the heavy liquid supply pipe 27, there is also a rising part 27a facing the center of the guide cylinder 14. Falling portions 28a are provided at eccentric positions at the ends of the light liquid supply pipes 28, respectively. According to this embodiment, not only can the same effects as in the previous embodiment be obtained, but also the supply pipe 2 shown in FIG.
Since the rising parts 7 and 28 can be omitted and the pipe line can be shortened, it is possible to facilitate the flow of both light and heavy liquids when using a centrifugal extractor in multiple stages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional centrifugal extractor, FIG. 2 is a sectional view of one embodiment of the present invention, and FIG. 3 is a sectional view of main parts of another embodiment. 11...Casing, 12...Rotating cylinder, 14
... Guide cylinder, 15 ... Partition wall, 16 ... Liquid supply chamber, 18, 20 ... Weir, 23 ... Weir constituent member, 26 ... Suction vane, 27 ... Heavy liquid supply pipe, 2
8...Light liquid supply pipe, 31...Heavy liquid, 32...Light liquid, 33...Interface.

Claims (1)

[Claims] 1. A liquid supply chamber is provided in the lower part of a casing that concentrically accommodates a rotating cylinder through a partition wall, and the partition wall has a lower end portion that opens into the liquid supply chamber and whose diameter decreases downward, and a lower end portion that opens at the center of the bottom surface of the rotating cylinder. Further, a guide cylinder having an upper end portion that engages therewith is provided, a suction blade positioned within the guide cylinder is installed at the center of the bottom surface of the rotary cylinder, and a suction blade located in the guide cylinder is installed at the center of the liquid supply chamber, and a suction blade is installed at the center of the liquid supply chamber, facing the center of the lower end of the guide cylinder. A centrifugal extractor characterized in that a heavy liquid supply pipe is provided that opens downward from the guide cylinder, and a light liquid supply pipe that opens above the guide cylinder is provided at an eccentric position.