JP2002336657A - Gas-liquid reaction column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-liquid reaction column having excellent separation performance of hydrogen isotopes and a stable separation function. SOLUTION: This gas-liquid reaction column is provided with a cylindrical vessel 1 having a hydrogen isotope introducing part, a liquid water introducing part and a discharge part of the hydrogen isotope produced by isotope exchange reaction. A rectangular cell 8 whose inside surface is made to have a vertically corrugated shape 29 and which is filled with a hydrophobic catalyst 2 is prepared so that the hydrogen isotope and liquid water can be introduced oppositely to each other and brought into countercurrent contact with each other. An assembly 11 formed by assembling a plurality of rectangular cells 8 is arranged inside the vessel 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid reactor for separating hydrogen isotope by bringing water in a liquid state and hydrogen isotope in a gaseous state into countercurrent contact inside the gas-liquid reactor.

[0002]

2. Description of the Related Art Conventionally, gas-liquid reaction towers for separating hydrogen isotopes include Separation of Hydrogen Isotope, ACS Symposium Series, VOL. 68, P171 ('Separation of Hydrogen I).
sotope'ACS Symposium Series, vol.68, P171)
Has proposed a method of attaching a device for once collecting and redispersing water in the middle of a reaction tower.

[0003] Further, a gas-liquid separation having two regions, ie, an on-catalyst reaction portion filled with a catalyst and a gas-liquid boundary reaction portion filled with a packing for containing water, without dispersing water on a hydrophobic catalyst. A tower has also been proposed (gas-liquid separation tower: “Concentration of heavy water”, RIKEN report, Vol. 63, No. 1).

FIG. 5 shows a general example of a conventional gas-liquid reaction tower (hereinafter, referred to as a reaction tower).

In this example, light water (H ₂ O) is introduced from above the reaction vessel 1 constituting the reaction tower 100 and tritium gas (HT) is introduced from below, and tritium water (HTO) is generated by a hydrogen exchange reaction. To separate tritium,
The gas-liquid reaction tower for recovering hydrogen gas containing tritium (HT) at a low concentration is shown. HT is gas inlet 4
It flows from bottom to top by the pressure difference between the gas outlet 5 and, H ₂ O
Enters the reaction vessel 1 through the liquid inlet 6 and the liquid disperser 3
And dropped in the reaction vessel by gravity. H
₂ O and HT contact in opposite directions, ie countercurrent. At this time, an isotope exchange reaction occurs between the hydrogen isotope and water by the catalyst 2 filled in the reaction vessel, and HT is converted into H by the reaction.
₂ and a high concentration of H ₂ gas to form a gas outlet 5
Released from Further, HTO and H ₂ O generated by the isotope exchange reaction are taken out from the liquid outlet 7.

The isotope exchange reaction proceeds by a two-stage continuous isotope exchange reaction represented by the following formula.

[Reaction on catalyst] HT (gas) + H ₂ O (steam) ⇔H ₂ + HTO (steam) (1) [Reaction on gas-liquid interface] HTO (steam) + H ₂ O (liquid) ⇔H ₂ O (steam) + HTO (gas) ... (2)

[0008]

A hydrogen isotope separation method utilizing an isotope exchange reaction between water in liquid state and hydrogen isotope in gaseous state is described by a gas-liquid countercurrent contact type reaction column using a catalyst. In addition, high separation performance can be expected when the separation coefficient in the equilibrium state is large. By the way, the catalyst used for the isotope exchange reaction in the gas-liquid reaction tower needs to be hydrophobic because the hydrophobic catalyst loses its activity when covered with liquid water.

When the hydrogen isotope exchange reaction is carried out in the vessel (reaction vessel) of the reaction tower by filling the hydrophobic catalyst as described above,
The reaction on the gas-liquid boundary surface, which depends on the gas-liquid boundary area, causes the supply water flowing in the reaction vessel to drift due to the catalyst having hydrophobicity. Maintenance becomes difficult. For this reason, there is a problem that it is difficult to predict the reaction amount of the isotope exchange. The drift of the supply water in the reaction vessel destabilizes the reaction behavior in the reaction vessel and causes a reduction in separation performance. In addition, it is difficult to estimate the area of the gas-liquid interface contributing to the reaction, which makes it difficult to design a reaction tower having high hydrogen isotope separation efficiency.

In order to increase the throughput of the reaction tower, it is conceivable to increase the diameter of the reaction vessel.

However, although the amount of the catalyst to be charged increases in proportion to the cross-sectional area of the reaction vessel, the water supplied to the reaction vessel is deflected irrespective of the cross-sectional area of the reaction vessel. Not only is it not possible to form an interface, but also the cost increases due to the height of the reaction tower,
In addition, there is a fear that a problem of complicating maintainability may occur.

The present invention reduces the size of the apparatus by reducing the uneven flow of the feedwater flowing in the reaction tower, without increasing the size of the apparatus.
It is an object of the present invention to provide a gas-liquid reaction tower having a high performance of separating hydrogen isotopes.

[0013]

According to the present invention, there is provided an aggregate of cells which are filled with a hydrophobic catalyst and whose corrugated shape is formed on a surface facing the hydrophobic catalyst, and the aggregate is arranged in a cylindrical container. The method is characterized in that the isotope exchange reaction of hydrogen isotope is performed by reducing the drift of the supply water in the cells of various shapes. The cross section of the cell has, for example, a rectangular shape, a circular shape, or a honeycomb shape. Hereinafter, when referring to a rectangular shape, a circular shape, or a honeycomb shape, it indicates a cross-sectional shape.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a first embodiment. FIG.
Is a schematic overall configuration diagram, FIG. 2 is a partially detailed diagram, and FIG. 3 is a perspective view of a rectangular cell. In FIG. 1, the same components as those of the reaction tower of FIG. 5 showing the conventional example are denoted by the same reference numerals, and the reaction tower 100 is a reaction vessel. A cylindrical container 1 (hereinafter, referred to as a cylindrical container) and a set of rectangular cells 11, 12, 13 arranged in multiple stages inside the container (in this case, a three-stage configuration). And a liquid separator 3 disposed above the cylindrical container 1. In FIG. 1, the aggregates 11, 1
It is shown that there is a gap between 2 and 13,
This is to make it easier to understand the arrangement of the aggregates 11, 12, and 13. Actually, the aggregates 11, 12, and 13 are in contact with each other in the vertical direction.

At the upper end of the cylindrical container 1, a gas outlet 5,
A liquid inlet 6 and a gas inlet 4 and a liquid outlet 7 at the lower end are provided. As shown in FIG. 1, when performing an isotope exchange reaction of tritium gas (HT), tritium gas (HT) is introduced from a gas inlet 4, and liquid water (H ₂ O) is introduced from a liquid inlet 6. , Tritium gas (HT) and hydrogen (H ₂ ) from the gas outlet 5, and tritium water (HTO) and water (H ₂ O), which are products of the isotope exchange reaction, from the liquid outlet 7. You. Tritium (T) is a hydrogen isotope.

FIG. 2 shows a part of the assemblies 11, 12, and 13 in detail. The aggregates are arranged in a plurality of stages of 11, 12, and 13. A liquid water inlet is provided above the uppermost aggregate 11, and a hydrogen isotope inlet is provided below the lowermost aggregate 13. And a countercurrent contact between the hydrogen isotope and the liquid water is made in the rectangular cells of each assembly.

In FIG. 2, for example, an aggregate 11 (also referred to as a unit) is formed by tightly joining rectangular cells 8 to each other by using a rectangular shape to form a substantially cylindrical shape as a whole. To be installed in Here, the rectangular cell facing the inner surface of the cylindrical container 1 is deformed so as to be in close contact with the inner surface of the cylindrical container 1 or formed between the cylindrical container 1 and the aggregate 11. The gap may be sealed.

In the case of this embodiment, the difference from the structure of the above-mentioned conventional example (FIG. 5) is that a unit structure is formed as a unit. By adopting this structure, the manufacturing and maintenance of the apparatus are improved. The remarkable merit is obtained in. That is, in the present structure, it is possible to manufacture the assembly, that is, for each unit, and it is possible to perform the maintenance for each unit.
In addition, a change in design such as a change in liquid contact area can be made in units of units, and there is an effect that flexibility in structural change can be provided. That is, the reaction amount of the isotope exchange can be adjusted by returning the inner surface area of the rectangular cell 8 in the aggregate unit.

FIG. 3 shows the configuration of the rectangular cell 8. In the rectangular cell 8, the side wall of the cell body 28, which is a rectangular tube, has a wavy shape 29 in the vertical direction, and the opening 1 is formed on the upper end surface and the lower end surface.
6, 17 respectively. It is important that the corrugated shape 29 is provided on the side wall of the cell body 28, particularly on the inner surface facing the catalyst, in the vertical direction, which is the direction in which the fluid flows. Therefore, the wall surface of the rectangular cell has a waveform shape in the vertical direction, that is, a waveform in which irregularities are repeated in the vertical direction of the wall surface.

The rectangular cell 8 has a rectangular cross section of about 10 mm. The size of this rectangle is the hydrophobic catalyst 2 to be filled.
Although it depends on the size, if the particle size is 2 to 3 mm, about 10 mm is preferable. Even if the cell is not rectangular, it is effective as long as it has a waveform on the inner surface, and it may be circular or honeycomb. A rectangular or honeycomb shape is effective in terms of space efficiency. In the case of a circular shape, the space formed between adjacent cells may be filled and used. The hydrophobic catalyst is a hydrophobic platinum catalyst having a diameter of about 2 mm (a platinum loading of 0.8).
wt%).

The outer surface of the rectangular cell can have a planar shape. A plurality of rectangular cells 8 having a wavy inner surface
Are unitized, that is, assembled into a unit, that is, an aggregate 11, and incorporated into the cylindrical container 1 as shown in FIG.

By doing so, the reaction tower 100 having the structure shown in FIG. 1 can be manufactured. In FIG.
As described above, the liquid water introduced from the liquid inlet 6 enters the cylindrical container 1 and is dispersed as fine water droplets by the liquid disperser 3. The water drops flow down in the rectangular cell 8 due to gravity. Further, tritium gas (HT) containing tritium as a hydrogen isotope is introduced from the gas inlet 4 and flows upward in the rectangular cell 8. At this time, the water droplet and the tritium gas flow in a wave shape depending on the wave shape 29 formed in the up and down direction, that is, influenced by the shape, and the two are brought into countercurrent contact.

At the time of this countercurrent contact, the catalyst 2 filled in the rectangular cell 8 causes an isotope exchange reaction between tritium gas (HT) and water. _{2 and} becomes high-concentration H ₂ gas, which is led out from the gas outlet 5. HTO and H ₂ O, which are products of the isotope exchange reaction, are taken out of the liquid outlet 7.

The isotope exchange reaction formula is the same as the above-mentioned reaction formula.

As described above, in the gas-liquid reaction tower 100 in which the hydrogen isotope exchange reaction is performed by the countercurrent contact between the hydrogen isotope and liquid water by utilizing the action of the hydrophobic catalyst, the hydrogen isotope is used. A cylindrical container 1 having an inlet (gas inlet 4), an inlet for liquid water (liquid inlet 6), and a outlet (liquid outlet 7) for hydrogen isotopes generated by the isotope exchange reaction is provided. The inside of the cylindrical container 1 has a wavy shape 29 in the vertical direction on the inner surface, and the inside is filled with the hydrophobic catalyst 2, and a hydrogen isotope and liquid water are introduced in opposition to each other to make countercurrent contact. Is formed, and a gas-liquid reaction tower provided with an aggregate 11 in which a plurality of rectangular cells 8 are assembled is provided.

The above-mentioned aggregates are arranged in a plurality of stages, liquid water is introduced from above the uppermost aggregate 11, and hydrogen isotopes are introduced from below the lowermost aggregate 13 to form each aggregate. Countercurrent contact between the hydrogen isotope and the liquid water is made in a rectangular cell of the body.

In a gas-liquid reaction method in which a hydrogen isotope is exchanged by countercurrent contact between the hydrogen isotope and liquid water by utilizing the action of a hydrophobic catalyst, the gas is disposed in the cylindrical container 1. The inner surface is formed into a wavy shape 29 in the up-down direction, and a hydrogen isotope and liquid water are introduced into a cell filled with the hydrophobic catalyst 2, for example, a rectangular cell 8, to face the wavy shape. A gas-liquid reaction method is provided in which a hydrogen-isotope exchange reaction is carried out by forming a dependent liquid flow of water and making a counter-current contact with the hydrogen isotope to form hydrogen and a hydrogen isotope after the exchange reaction Is done.

By making the rectangular cell 8 corrugated, the contact area between the rising hydrogen isotope and the flowing water can be increased, and the falling speed of the liquid traveling on the wall surface can be controlled. By increasing the area and suppressing the falling speed of the liquid water, a desired gas-liquid reaction can be efficiently promoted. The shape of the waveform may be a smooth semicircular arc shape or a jagged mountain shape. These processes may be performed by a mechanical process, a press process, or the like.

The rectangular shape does not need to be a geometric rectangular shape, but may be any rectangular shape.

The hydrogen isotopes include H ₂ O, HTO, T ₂ O and the like in addition to the above-mentioned tritium gas (HT).

According to the gas-liquid reaction tower 100 having the rectangular cells 8 which are vertically corrugated, the liquid cells are well dispersed because of the rectangular cells inside. Further, the gas-liquid reaction is promoted by the corrugated portions of the rectangular cells, and the reaction efficiency is remarkably improved.

When handling tritium, which is a radionuclide, as a hydrogen isotope, safety measures are required to protect the user from the radiation. The reaction tower (reactor) according to the embodiment of the present invention can be made smaller than the conventional type, so that there is also an advantage that the storage container required for safety measures can be reduced in size and cost can be reduced. The reaction tower is installed in the containment. Further, since the unit structure is adopted, manufacture and maintenance of the device are easy, and the safety of the device is improved.

The adoption of the rectangular cell structure having a wavy shape up and down can significantly increase the gas-liquid contact area, form a wide and stable gas-liquid boundary surface, and increase the gas-liquid contact time. Therefore, the separation performance of the reaction tower is improved and stabilized. Further, since the gas-liquid contact area can be estimated and effective control can be performed, designability is improved.

Although the gas outlet 5 and the liquid inlet 6 are shown separately in the drawing, they may be integrally formed. The same applies to the gas inlet 4 and the liquid outlet 7.

FIG. 4 shows a second embodiment. The same components as those of the first embodiment are denoted by the same reference numerals, and the same components will not be described repeatedly. Therefore, the first embodiment should be referred to.

The function of the second embodiment is basically the same as that of the first embodiment. However, regarding the treatment of the mixed water of HTO and H ₂ O, the four-stage aggregate, that is, the aggregate is 21 and 2
2, 23 and 24 are arranged in the cylindrical container 1 and
Another liquid disperser 33 is disposed between the fuel cell and the assembly 23, and an oxidation reactor 9 is provided in communication with the upper gas outlet 5 and the liquid inlet 6, and the lower gas inlet 4, An electrolyzer 20 is provided in communication with the liquid outlet 7. A treated water inlet 10 is provided near the center of the side of the cylindrical container 1, and treated water from the treated water inlet 10 is guided to the liquid disperser 33 to be formed as water droplets and introduced into the aggregates 23 and 24. .

In the second embodiment, the mixed liquid (mixed water) in which H ₂ O and HTO are mixed, that is, treated water (water treated for other purposes) has a tritium concentration. The present invention relates to an apparatus and a method for separating water having a low tritium concentration and water having a high tritium concentration.

At the beginning of the operation, HTO is charged into the lower part of the cylindrical container 1 and is electrolyzed in the electrolytic device 20 to convert the HTO into the HT.
Is generated. When this state is maintained, the inside of the cylindrical container 1 has a distribution state in which the tritium concentration is high downward and the tritium concentration is low toward the top. The lower part becomes the enrichment part and the upper part becomes the impairment part around the center. In the next step, HTO and H ₂ O
And mixed water.

The treated water in which H ₂ O and HTO are mixed is dropped and dispersed by the liquid disperser 33 from the treated water inlet 10. The treated water dropped and dispersed is collected into the aggregates 23 and 2
4 flows in the rectangular cell constituting part 4, and a part of H ₂ O evaporates, and a part of HTO becomes HT. The HTO that has reached the electrolyzer 20 without gasification is converted into an HT by electrolysis here.
become. The upwardly flowing HT is in countercurrent contact with the downwardly flowing steam or water. Further, the HT causes the same phenomenon even in the rectangular cells constituting the aggregates 21 and 22 located above, and the HT comes into countercurrent contact with H ₂ O dripped downward.

As described above, in the electrolytic cell 20 at the bottom, HTO is electrolyzed to generate tritium gas (HT).

2HTO → 2HT + O ₂ (3) In the upper oxidation reactor 9, H ₂ is converted to H ₂ O by an oxidation reaction. H ₂ + 1 / 2O ₂ → H ₂ O (4) The generated H ₂ O is introduced into the cylindrical container 1 from the liquid inlet 6 and is subjected to a circulation operation.

When such an operation is performed, the cylindrical container 1
A large tritium concentration difference can be created between the upper part and the lower part.

The treated water in which H ₂ O and HTO are mixed is introduced from the treated water inlet 10 and dispersed in the rectangular cell 8 using the liquid disperser 33, so that the bottom of the cylindrical container 1 is removed. Retreated water containing tritium-rich tritium water HTO is supplied from the tritium water outlet 31, and H-containing tritium is added to the light water outlet 32 at the top of the tower.
₂ O will be exhausted.

As described above, in the gas-liquid reaction column in which the hydrogen isotope is exchanged by the countercurrent contact between the hydrogen isotope and liquid water by utilizing the action of the hydrophobic catalyst, the introduction of the hydrogen isotope is performed. A cylindrical container having a gas inlet section 4, a liquid water inlet section (liquid inlet section 6), and an outlet section (liquid outlet section 7) for hydrogen isotopes generated by the isotope exchange reaction. Inside the cylindrical container, the inner surface is formed into a wavy shape 29 in the up and down direction, the inside is filled with the hydrophobic catalyst 2, and a hydrogen isotope and liquid water are introduced to face each other to make a countercurrent contact. A shape cell 8 is formed, and aggregates 21, 22, 23, and 24 in which a plurality of rectangular cells are gathered are arranged, and a hydrogen isotope is provided.
An introduction section (treated water inlet section 10) for introducing a mixed water obtained by mixing liquid water is provided, and a liquid disperser 33 is provided in the middle of a multi-stage array to disperse the mixed water. The disperser 33 provides a gas-liquid reaction tower that is dropped and dispersed.

It is not described that the hydrogen isotope introduction part, the liquid water introduction part, and the hydrogen isotope derivation part generated in the isotope exchange reaction are open to the outside. Instead, it is for a cylindrical container.

[0047]

As described above, the cells having a corrugated shape on the inner surface, in particular, the rectangular cells are provided in the cylindrical container so that the hydrogen isotope and the liquid water are brought into countercurrent contact to disperse the cells. The drift of the flowing water is reduced, and the countercurrent contact between the hydrogen isotope and the dispersed flowing water is improved without increasing the size of the cylindrical container. Since a gas-liquid boundary surface is formed and the gas-liquid contact time can be increased, it is easy to estimate and control the contact area of the hydrogen isotope in the reaction tower, and the design is improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional configuration diagram of a reaction tower according to an embodiment of the present invention.

FIG. 2 is a partially detailed view showing a state where a rectangular cell assembly is drawn from a gas-liquid reaction tower.

FIG. 3 is an enlarged view of the rectangular cell shown in FIG. 2;

FIG. 4 is a schematic cross-sectional configuration diagram of a reaction tower according to another embodiment of the present invention.

FIG. 5 is a diagram showing an example of a conventional reaction tower.

[Explanation of symbols]

1 ... cylindrical container (or reaction container), 2 ... hydrophobic catalyst,
3, 33 liquid disperser, 4 gas inlet, 5 gas outlet, 6 liquid inlet, 7 liquid outlet, 8 rectangular cell, 9 oxidation reactor, 10 treated water inlet , 11,1
2,13,21,22,23,24 ... aggregate, 14,2
0: electrolytic cell, 28: rectangular cell body, 29: waveform shape, 3
1 ... tritium water outlet, 32 ... light water outlet, 100 ...
Gas-liquid reaction tower (gas-liquid reaction device).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sumi Yoshida 3-2-1, Sachimachi, Hitachi-shi, Ibaraki Prefecture Within Hitachi Engineering Co., Ltd. (72) Inventor Tetsuyuki Konishi 801 Mukaiyama, Nakamachi, Naka-machi, Naka-gun, Ibaraki (1) Inside the Japan Atomic Energy Research Institute Naka Research Laboratory (72) Inventor Masataka Nishi 2-4 Shirane, Shirokata, Tokai-mura, Naka-gun, Ibaraki Pref. CB15 DA22 4G075 AA03 BA10 BD13 BD23 DA02 EA01 EB09 EE01

Claims (4)

[Claims] 1. A gas-liquid reaction column for performing a hydrogen isotope exchange reaction by countercurrent contact between a hydrogen isotope and liquid water by utilizing the action of a hydrophobic catalyst. A tubular container having a water-introduced portion and a hydrogen isotope deriving portion generated by the isotope exchange reaction, and a tubular container filled with a hydrophobic catalyst therein; and a hydrophobic catalyst inside the tubular container. A cell that forms a counter-current contact by introducing a hydrogen isotope and liquid water facing each other is formed in an up-down corrugated shape, and an aggregate of a plurality of cells is disposed. A gas-liquid reaction tower, characterized in that: 2. The assembly according to claim 1, wherein said assembly is provided in a plurality of stages in a vertical direction, a liquid water introduction portion is provided above the uppermost assembly, and below said lowermost assembly. A gas-liquid reaction tower provided with a hydrogen isotope introduction portion, wherein countercurrent contact between the hydrogen isotope and liquid water is made in a rectangular cell of each assembly. 3. The cylindrical container according to claim 1, further comprising an introduction portion for introducing a mixed water obtained by mixing liquid water and a hydrogen isotope generated by an isotope exchange reaction, wherein the aggregate is provided in the cylindrical container. A gas-liquid reaction tower comprising a plurality of vertically arranged stages in a container, a liquid disperser provided between the aggregates, and the mixed water dropped and dispersed by the liquid disperser. 4. The gas-liquid reaction tower according to claim 1, wherein the cross-sectional shape of the cell is rectangular, circular, or honeycomb.