JP2022033275A - Distillation separation method and distillation separator using filler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filler which is a porous body and which can reduce the height of filling to the height of a practical level and to provide a distillation separation method and a distillation separator using the filler.

MEANS: In a filler filled in a distillation column supplied with a treatment liquid,: at least a surface thereof is covered with a fine pore forming means constituted with a porous body expressing a capillary phenomenon; the fine pore forming means is a metal-sprayed layer or a metal-sintered body; an aluminum-sprayed layer is used as the metal-sprayed layer; "aluminum spray coating MATSUI regulation 250S" is exemplified as the filler using the aluminum-sprayed layer; and "porous aluminum cruciform" constituted with an aluminum-sintered body is exemplified as the filler using the metal-sintered body.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a packed material used in a packed tower, a distillation separation method and a distillation separation device using the packed material, and in particular, a distillation separation method and a distillation separation method that can be suitably carried out for separation of tritiated water and light water. It relates to a distillation separation device.

In a distillation separation device that uses a packed column as a distillation column, when distillation separation of components with close specific volatility is performed using a conventionally used packing material such as glass beads, the number of stages of the distillation column becomes a practical level. A large number of stages exceeding the number is required. For example, in the case of distillation separation of tritiated water, it has been reported that a reflux ratio of 30 and a theoretical plate number of 230 are required to concentrate the concentration 10 times (see Non-Patent Document 1 below). Here, the number of stages can be reduced by increasing the reflux ratio. However, if an attempt is made to increase the reflux ratio, it is necessary to increase the energy, which leads to an increase in energy cost.

Therefore, in order to solve such a problem, it has been proposed that a packed tower type distillation separation using an adsorbent that selectively adsorbs the component to be distilled-separated as a filler is effective (the following non-distillation). See Patent Document 2). According to this Non-Patent Document 2, when the distillation separation method when silica gel beads are used as a filler is examined, it is presumed that the number of theoretical plates can be 133 with the same reflux ratio.

When a selective adsorbent such as silica gel beads is used as the filler as in the above-mentioned conventional example, the reflux ratio and the number of theoretical plates can be significantly reduced. However, since a high reflux ratio is still required and a special manufacturing method is required for manufacturing the adsorbent, there is a problem that the energy required for operation becomes enormous and the manufacturing cost of the filler becomes high.

On the other hand, in recent years, a filler made of a porous body having continuous ventilation holes having a specific pore diameter inside thereof even if it is not adsorptive has been proposed (see Patent Document 1 below). The filler of Patent Document 1 is, for example, a porous body made of polypropylene, and has an average pore size of 80 to 300 μm. In the filler having such a structure, the wet surface area becomes large due to the permeation of the liquid into the communication holes. As a result, it is said that the separation performance can be improved by increasing the gas-liquid contact area.

Publication No. 55-8819

"2009 Evaluation of Tritium Removal and Mitigation Technologies for Wastewater Treatment", DOE / RL-2009-18 "Tritium Isotope Separation by Water Distillation Column Packed with Silica-gel Beads", Journal of NUCLEAR SCIENCE and TECHNOLOGY Vol.41, No.5 pp619-623

However, the above-mentioned porous body made of polypropylene and a filler having continuous ventilation holes having an average pore diameter of 80 to 300 μm has not yet obtained sufficient separation performance. As will be described later in the section of [Example], the HETP (equivalent height per theoretical plate) is a considerably high value according to the experiments by the present inventors, and the filling height is practical. It has been proven that it cannot be lowered to the height of the level.

The present invention has been conceived in view of the above problems, and an object thereof is a filler that is a porous body and can reduce the filling height to a practical level, and distillation using the filler. It is to provide a separation method and a distillation separation apparatus.

In order to achieve the above object, the invention according to claim 1 is a filler filled in a distillation column to which a treatment liquid is supplied, and at least the surface thereof is a micropore made of a porous material that exhibits a capillary phenomenon. It is covered with a forming means, and the micropore forming means is characterized by being a metal spray layer or a metal sintered body.

Here, "at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon" means that the entire filler is made of the micropore-forming means and the filler base. It means that the case where the micropore forming means is configured to cover only the surface of the material is included.

According to the above configuration, the liquid penetrating the inside of the micropores seeps out to the surface of the filler due to the action of the capillary phenomenon and diffuses so as to cover the surface of the filler in a short time. Increased and increased mass transfer rate in the distillation column. As a result, the distillation separation method (invention according to claim 4) capable of reducing HETP (height equivalent of theoretical plate) and reducing the filling height to a practical level. The distillation separation device (the invention according to claim 5) can be realized.

The invention according to claim 2 is the filler according to claim 1, wherein the metal sprayed layer is an aluminum sprayed layer.

The invention according to claim 3 is the filler according to claim 1, wherein the metal sintered body is an aluminum sintered body.

The invention according to claim 4 is a distillation separation method characterized by performing distillation separation of a stock solution to be treated by using a distillation column filled with the filler according to any one of claims 1 to 3. ..

According to the above configuration, it is possible to realize a distillation separation method in which the separation performance is improved and the filling height can be lowered to a practical level.

The invention according to claim 5 is a distillation separation device provided with a distillation column, wherein the distillation column is filled with the filler according to any one of claims 1 to 3.

According to the above configuration, it is possible to realize a distillation separation device capable of improving the separation performance and reducing the filling height to a practical level.

According to the present invention, the liquid penetrating into the pores seeps out to the surface of the filler due to the appearance of the capillary phenomenon, and diffuses so as to cover the surface of the filler in a short time, so that the air-liquid contact area increases. And the mass transfer rate in the distillation column is increased. As a result, it is possible to realize a distillation separation method and a distillation separation device that can reduce HETP (height equivalent of theoretical plate) and reduce the filling height to a practical level. be able to.

A graph showing the height of the capillary water column for each combination of material and capillary radius related to the capillary structure. The graph which shows the liquid permeation rate (expressed by the time to advance 10 mm) for each combination of a material and a capillary radius about a capillary structure. Overall configuration diagram of a distillation separation device using a filler composed of a capillary structure for a distillation column.

Hereinafter, the present invention will be described in detail based on the embodiments. The present invention is not limited to the following embodiments.
(Embodiment)
The filler according to the present embodiment is a filler filled in a distillation column to which a treatment liquid is supplied, and is composed of a capillary structure. Here, the "capillary structure" is composed of a porous body having a large number of pores, and the liquid that permeates the pores seeps out to the surface of the filler due to the action of the capillary phenomenon, and the surface of the filler is exposed. It means a structure configured so that a state of diffusion so as to cover in a short time can occur. Here, the "pore" means a minute cavity contained in a group of objects, and includes an open pore connected to the outside air and a closed pore isolated inside the object. "Void" means a minute cavity contained in a group of objects, including open pores connected to the outside air and closed pores isolated inside the object. Further, here, "short time" means that the liquid flowing down the surface of the filler enters the pores and is temporarily interrupted at the position, and at least until the subsequent flowing liquid passes from the interrupted state at the position. It means an extremely short time during which the liquid penetrating the pores diffuses so as to cover the surface of the filler and is allowed to come into contact with the subsequent flowing liquid. The specific meaning of "short time" is explained in paragraph 1981 of [Example] described later.

Further, as a specific configuration of the capillary structure, the height of the capillary water column is at least a predetermined value, and the permeation rate at which the liquid permeates the inside of the capillary structure is at least a predetermined value. It is necessary that the time required to penetrate the predetermined length is less than or equal to the predetermined time). Here, by limiting the height of the capillary water column to a predetermined value or more, the material and pore diameter of the porous body for obtaining the capillary force required for the capillary structure are determined as described later. The material and pore size of the porous body for obtaining the fluidity of the liquid required for the capillary structure are determined by the limitation that the permeation rate at which the liquid permeates the inside of the capillary structure is a predetermined value or more.

Hereinafter, the background to the present embodiment will be described first, and then the specific concept of the height of the capillary water column of the capillary structure and the specific concept of the liquid permeation rate of the capillary structure will be described in detail.

[Background to the embodiment]
When the present inventors provide a space inside the structure to the extent that the capillary force acts, the liquid spreads to all surfaces by the capillary force, and as a result, the force that the liquid covers the entire surface of the filler acts. However, it has been found that a gas-liquid contact device using this force significantly increases the mass transfer rate.
Conventionally, a surface treatment for improving the wettability of the surface of the filler (for example, physical sand blasting or chemical surface treatment when a stainless steel material is used especially in an aqueous system) is performed. However, although these are intended to reduce the contact angle with the liquid (especially in the case of water) and improve the wettability, the wet area is inevitably limited to a certain proportion of the physical surface area as long as the contact angle exists. , The area is much smaller than the physical surface area for which a predictive formula has been proposed.

For example, the calculation as an example of a regular filling is as follows. Several model formulas of this type have been proposed, but here we used the SRP model (abbreviation of University of Texas Separation Research Program :) that includes the contact angle element.

Here, by substituting the condition values in Table 1 below into the numbers 3 to 8,

Even if the contact angle of the filling surface could be improved to 50 ° by trying to improve the wettability, the value remains at 0.14, especially when the superficial velocity of the liquid is small (5 m ³ / m). (Like ^2h ) shows how many areas are not working effectively.
Therefore, if the filler to be filled in the distillation column is composed of a capillary structure, the present inventors spread the liquid to all surfaces by the capillary force, and as a result, the liquid covers the entire surface of the filler. I found that force works. For example, if the contact angle between the constituent material and water is the same, the capillary force increases as the pore diameter becomes smaller. However, the filler used in the distillation column is not effective simply because it has a capillarity. The present inventors have found that the speed at which the liquid flows in the capillary tube is an important factor. As a result, HETP (height equivalent of theoretical plate) can be reduced by increasing the gas-liquid contact area and the mass transfer rate in the distillation column, and the filling height can be set to a practical level. Can be lowered to height.

[Capillary water column height of capillary structure]
The height of the capillary water column is an index for evaluating the capillary force of the capillary structure. Specifically, the capillary force is approximately expressed by the capillary water column in one capillary tube, and is based on the following number 8. The water used is at room temperature.

Here, θ (contact angle) and the capillary radius r adopt the values in Table 2 below, and the capillary water column height is calculated using the number 8 for each combination of the constituent material and the capillary radius r, and the calculation result is obtained. It is shown in Table 3. In addition, the height of each capillary water column shown in Table 3 is shown as a graph in FIG. In FIG. 1, the height of the capillary water column in the glass beads (r = 10 μm), the cellulose capillary structure (r = 10 μm), the plastic capillary structure (r = 5 μm) and the ceramic capillary structure (r = 35 μm) is , All of them are values outside the frame, so they are drawn up to 0.3m.

In FIG. 1, glass beads have a capillary radius of 500 μm, an aluminum capillary structure has a capillary radius of 330 μm, plastic has a capillary radius of 100 μm, a ceramic capillary structure has a capillary radius of 390 μm, and a stainless steel capillary structure has a capillary radius of 180 μm, or copper. When the capillary structure has a capillary radius of 270 μm, the height of the capillary water column is about 0.03 m. Further, when the plastic has a capillary radius of 50 μm, the height of the capillary water column is about 0.05 m. In the other cases in FIG. 1, the height of the capillary water column is much larger than about 0.05 m. Therefore, as the capillary force of the capillary structure, it is preferable that the height of the capillary water column is at least 0.03 m or more, and more preferably 0.05 m or more. It is proved by Examples and Comparative Examples to be described later that the capillary structure having 0.03 m or more, more preferably 0.05 m or more, reduces HETP (theoretical stage equivalent height) (more accurately explained). In addition to the condition of having 0.03 m or more, more preferably 0.05 m or more, there is also a condition that the time (seconds) for advancing 10 mm, which will be described later, is within 0.1 seconds, more preferably within 0.05 seconds. Proof when added).

[Liquid permeation rate of capillary structure]
The liquid permeation rate of the capillary structure is expressed by the expression that the time required for the liquid to permeate a predetermined length is not more than a predetermined time.

Even if the capillary structure is the same, if the void size is too small, the fluidity due to the capillary phenomenon decreases due to the flow friction, and the mass transfer rate of the packed column is decreased. Therefore, it is considered that the flow of the liquid expands in the capillary structure because the capillary force and the frictional resistance flowing through the capillary become equal, and the time for tentatively penetrating 10 mm in the horizontal direction is calculated by the following equation 9. It is shown in Table 4 below. This Table 4 shows the time (seconds) to travel 10 mm calculated for each combination of the same material and capillary radius as in Table 3. In addition, the time (seconds) for advancing each 10 mm shown in Table 4 is shown as a graph in FIG. In FIG. 2, the time (seconds) in the plastic capillary structure (r = 5 μm) is a value outside the frame, so it is drawn up to 1.2 seconds.
In addition, although the number 12 is shown in the literature as the Lucas-Washburn formula, the capillary flow is analyzed using the Hagen-Poiseuille flow formula using the one obtained by converting the capillary force into the pressure difference. ..

This indicates that the flow velocity when the liquid flows inside the structure due to the capillary force is related to the mass transfer velocity of the packed column. Even if the capillary force is large, the structure in which the liquid permeates is fine, and the structure in which the permeation rate is slow is ineffective or small in increasing the mass transfer rate. Distillation separation tests using various packed materials have shown that this time is within 0.1 seconds, more preferably within 0.05 seconds for permeating 10 mm, for mass transfer rates in packed beds. It was found to be effective in increasing.

Specifically, in FIG. 2, the glass beads have a capillary radius of 10 μm, the aluminum capillary structure has a capillary radius of 40 μm, the cellulose capillary structure has a capillary radius of 10 μm, the plastic capillary structure has a capillary radius of 5 μm, and the plastic capillary structure. When the capillary radius is 50 μm, the capillary radius is 100 μm in the plastic capillary structure, or the capillary radius is 35 μm in the ceramic capillary structure, the time required is 0.1 seconds or more. If the glass beads have a capillary radius of 50 μm, the aluminum capillary structure has a capillary radius of 50 μm, the stainless capillary structure has a capillary radius of 75 μm, or the copper capillary structure has a capillary radius of 50 μm, the time required is 0.05 seconds or longer. Is. In the other cases in FIG. 2, the time required is much smaller than 0.05 seconds. Therefore, the permeation rate of the capillary structure is preferably at least 0.1 seconds or less, and more preferably 0.05 seconds or less. It is proved by Examples and Comparative Examples to be described later that the capillary structure having a time of 0.1 seconds or less, more preferably 0.05 seconds or less, reduces HETP (theoretical stage equivalent height) (more accurately explained). Therefore, in addition to the condition that the height is within 0.1 seconds, more preferably within 0.05 seconds, the height of the capillary water column is preferably 0.03 m or more, more preferably 0.05 m or more. It is proved when the condition of having is also added).

[Specific example of preferable capillary structure]
A capillary structure satisfying the above conditions of [capillary water column height of capillary structure] and [liquid permeation rate of capillary structure] is preferable. In consideration of industrial production, it is preferable to use ceramic, stainless steel, aluminum, or copper as the material. From such conditions, as a specific preferable capillary structure, the pore diameter is 70 μm (corresponding to the capillary radius r = 35) or more, 800 (corresponding to the capillary radius r = 400, and r = 390 in the above example. ) Μm or less ceramic capillary structure, pore diameter 150 μm (corresponding to capillary radius r = 75), 400 (corresponding to capillary radius r = 200, r = 180 is used in the above example) μm or less Stainless steel capillary structure, aluminum capillary structure with pore diameter of 80 μm (corresponding to capillary radius r = 40) and 700 (corresponding to capillary radius r = 350, r = 330 is used in the above example) μm or less , And a copper capillary structure having a pore diameter of 100 μm (corresponding to a capillary radius r = 50) and 500 (corresponding to a capillary radius r = 250, r = 270 is used in the above example) μm or less.

[Application example of distillation separation device]
FIG. 3 is an overall configuration diagram of a distillation separation device using a filler made of a capillary structure in a distillation column. The undiluted solution supplied to the distillation separation device 1 is light water (H ₂ O) containing tritiated water (HTO or T ₂ O). In this distillation separation device 1, light water (H ₂ O) containing tritiated water (HTO or T ₂ O) is separated into tritiated water having a higher concentration than the undiluted solution and tritiated water having a lower concentration than the undiluted solution. used.

The distillation separation device 1 cools the refillable multi-stage distillation column 2, the reboiler 3 that heats and vaporizes the stored liquid at the bottom of the distillation column 2, and the steam supplied from the top of the distillation column 2. A condenser 4 for liquefying, a reflux tank 5 for storing the condensed liquid from the condenser 4, and a pump 6 provided on the reflux line L1 for refluxing the condensed liquid from the bottom of the reflux tank 5 to the top of the distillation column 2. , A control valve V1 provided on the reflux line L1 and a cooling tank 7 as a supply source of cooling water supplied to the condenser 4. As the filler of the distillation column 2, a filler made of a capillary structure is used. The bleed air of the condenser 4 is connected to a vacuum pump (not shown) provided separately, and the inside of the distillation column 2 is evacuated by this vacuum pump. Further, the operating temperature is controlled to a predetermined value by adjusting the degree of vacuum of the vacuum pump.

The distillation separation device 1 is provided with a thermometer, a pressure gauge, and a flow meter, if necessary. Examples of the thermometer, pressure gauge and flow meter include a thermometer T1 and a pressure gauge P1 provided at the top of the distillation tower 2, a thermometer T2 and a pressure gauge P2 provided at the bottom of the distillation tower 2, and a reflux line L1. F1, thermometer T3 and flow meter F2 provided in the cooling water flow line L2, thermometer T4 provided in the cooling water return line L3, and recirculation. Examples thereof include a thermometer T5 provided in the tank 5.

The operation of the distillation separation device 1 having the above configuration is the same as that of a general distillation separation device. Briefly described below, the undiluted solution is supplied from the central portion of the distillation column 2, flows down in the distillation column 2, and is heated by the reboiler 3 at the bottom of the distillation column 2 to generate steam. The generated steam rises in the distillation column 2 and undergoes gas-liquid contact with the undiluted solution descending in the distillation column 2. At this time, since the filler is a capillary structure, a state in which the liquid diffuses so as to cover the entire surface of the filler is exhibited. As a result, the gas-liquid contact area is increased, gas-liquid contact can be performed on more contact surfaces, and the separation performance is improved.

Then, in the process of this gas-liquid contact, the tritium concentration in the descending liquid increases, and the tritium concentration in the ascending steam decreases. Then, the rising steam after the gas-liquid contact reaches the top of the column and is further guided to the condenser 4. In the condenser 4, the supplied steam is cooled by the cooling water, and a part of the steam is returned to the top of the column (reflux) through the reflux tank 5, and a part of the steam is discharged as low-concentration tritiated water having a lower tritiated concentration than the undiluted solution. Is discharged from. On the other hand, the descending liquid after the gas-liquid contact is stored in the bottom of the column, and a part of this stored liquid is recovered from the discharge line L5 as high-concentration tritiated water having a higher tritiated concentration than the undiluted solution.

(Other matters)
(1) The pores of the capillary structure may be communication holes or independent holes.

(2) It is preferable that the surface of the capillary structure is hydrophilized.

(3) The filler may be a columnar bead or a spherical bead, and may be a regular filler or an irregular filler having appropriate pressure loss characteristics, which is often used in an actual device. , A filler having a porous surface thereof may be adopted, or a porous material may be supported on the surface. Even with such a configuration, the same effect can be achieved.

(4) In the above embodiment, tritiated water is used as the "liquid (stock solution) to be treated", but the present invention is not limited to this, and heavy water and other isotopes having close specific volatility are used. It can also be applied to the separation of the body.

(5) The distillation separation device is not limited to the above embodiment, but is provided with a steam compressor that functions as a heat pump, and the steam from the top of the distillation column is reused as a heating source for the reboiler using the steam compressor. It may be an energy-saving type distillation separation device.

(6) As the filler (corresponding to the capillary structure) in the above embodiment, at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon, and the micropore-forming means is a metal. It may be a sprayed layer or a metal sintered body. Here, "at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon" means that the entire filler is made of the micropore-forming means and the filler base. It means that the case where the micropore forming means is configured to cover only the surface of the material is included.

Further, the metal sprayed layer is preferably an aluminum sprayed layer. As a filler using an aluminum sprayed layer, "Aluminum sprayed Matsui Rule 250S" (corresponding to Example 6 described later) is exemplified.

Further, the metal sintered body is preferably an aluminum sintered body. As a filler using an aluminum sintered body, a “porous aluminum cross shape” (corresponding to Example 5 described later) composed of an aluminum sintered body is exemplified.

Here, it is proved by the third experimental example described later that the filler using the aluminum sprayed layer can reduce the HETP (height equivalent to the theoretical stage) and the filler height to a practical level. Has been done. Further, it is proved by the second experimental example described later that the filler using the aluminum sintered body can reduce the HETP (height equivalent to the theoretical stage) and the filling height can be lowered to a practical level. Has been done.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples. In the following examples and comparative examples, the same as the above embodiment except that the size of the distillation column (the body diameter of the actual distillation column as in the embodiment is several m level) is different. Distillation separation was performed using the undiluted solution as heavy water using various fillers having different materials and pore diameters using a test distillation separation device having a configuration.

[Example of the first experiment]
As the first experimental example, the following Examples 1 to 4 and Comparative Examples 1 to 4 were performed. In this first experimental example, as described below, a glass column having an inner diameter of 18 mm was used as the packed column.

(Example 1)
Alumina columnar beads (Product No. R-200 manufactured by Nishimura Ceramics Co., Ltd.) having a diameter of 0.34 cm and a length of 0.4 cm were used as the filler. Micropores of about 10 μm are provided on this surface.
The packed tower used was a glass column having an inner diameter of 18 mm filled with the above-mentioned filler so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 70 to 75 W for steady operation. The distillate amount at this time was about 150 ml / h (evaporation rate was 590 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 0.699%
Condensate at the top of the tower; 0.563%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.81

(Example 2)
Cellulose porous beads (trade name: Biscopearl P type, Rengo Co., Ltd.) having a diameter of 0.3 to 0.4 cm were used as a filler. Micropores of about 20 to 30 μm are provided on this surface. The packed tower used was a glass column having an inner diameter of 18 mm filled with the above filling so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 60 to 65 W for steady operation. The distillate amount at this time was about 150 ml / h (evaporation rate was 590 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 0.828%
Condensate at the top of the tower; 0.629%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.76

(Example 3)
As the filler, porous glass beads (manufactured by ROBU), which is a sintered body of glass having a diameter of 0.3 to 0.4 cm, were used. Micropores of about 40 to 100 μm are provided on this surface. The packed tower used was a glass column having an inner diameter of 18 mm filled with the above-mentioned filler so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 60 to 65 W for steady operation. The distillate amount at this time was about 80 ml / h (evaporation rate was 300 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensate at the top of the column with a gas chromatograph, and the following data Got

Boiler concentrate; 0.980%
Condensate at the top of the tower; 0.523%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.53

(Example 4)
As a filler, a porous alumina plate (manufactured by NDC Sales Co., Ltd.), which is a sintered body of aluminum, was processed into pellets having a diameter of 0.3 to 0.4 cm and used. Micropores of about 200 μm are provided on this surface. The packed tower used was a glass column having an inner diameter of 18 mm filled with the above filling so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 60 to 65 W for steady operation. The distillate amount at this time was about 70 ml / h (evaporation rate was 270 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 0.771%
Condensate at the top of the tower; 0.482%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.63

(Example 4-2)
The filler used in Example 4 was subjected to a hydrophilic treatment (boehmite treatment) to improve the wettability of the surface, and the same test as in Example 4 was carried out using the filler subjected to the hydrophilic treatment. gone.
Boiler concentrate; 0.753%
Condensate at the top of the tower; 0.436%
Separation coefficient (tower concentration ÷ boiler concentration) = 0.58

(Comparative Example 1)
Using the same equipment as in the examples, the same operating conditions were adopted, glass beads (4 mmφ) without micropores were filled in the filler at the same filling height, and the heavy water concentration was measured in the same manner as follows.

Boiler concentrate; 0.792
Condensate at the top of the tower; 0.703
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.89

(Comparative Example 2)
Using the same equipment as in the examples, using the same operating conditions, the filler is filled with zeolite beads (Union Showa product number MS-13X, 3-4 mmφ) at the same filling height, and the heavy water concentration is measured in the same manner. It became as follows.

Boiler concentrate; 0.967
Condensate at the top of the tower; 0.844
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.87

(Comparative Example 3)
Using the same equipment as in the examples, the same operating conditions were adopted, and the filler was filled with a PP (polypropylene) plastic sintered porous body and a pore diameter of 200 μm (Fuji Chemical thickness 4 mm) at the same filling height. The measurement of heavy water concentration was as follows.

Boiler concentrate; 0.785
Condensate at the top of the tower; 0.691
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.88

(Comparative Example 4)
With the same equipment as in the examples, the same operating conditions were adopted, and the filler was filled with a PP (polypropylene) plastic sintered porous body, a pore diameter of 100 μm (Fuji Chemical thickness 4 mm) at the same filling height, and similarly heavy water. The concentration was measured as follows.
Boiler concentrate; 0.726
Condensate at the top of the tower; 0.785
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.93

Here, the HETP (height equivalent to the theoretical stage) of the distillation column was calculated in the above-mentioned Example and the above-mentioned Comparative Example, and the results are shown in Table 5 below. However, the specific volatility of heavy water at 100 ° C. was 0.975.

The following formula was used to calculate HETP.
HETP = Z / N
N = {Log (Separation Factor) / Log (α)} -1
However, Separation Factor: Separation coefficient α: Specific volatility Z: Packed bed height [m]

(Examination of experimental results in the first experimental example)
(1) From Table 5, it is clarified that the HETP of Examples 1 to 4-2 is 15 to 49% of the HETP of Comparative Example 1 (glass beads whose filling is no pores). This leads to the fact that HETP can be lowered depending on the presence or absence of pores in the packing.

(2) Further, from Table 5, it is clarified that the HETP of Examples 1 to 4-2 is 22 to 72% of the HETP of Comparative Example 2 (filling is zeolite beads). From this, the following matters are derived. That is, the zeolite beads are also porous like the fillers of Examples 1 to 4-2, but their pore size is, for example, 0.15 to 0.43 μm, and the cavity portion having a too porous structure is formed. Because it is small, it takes too much time to move the liquid. Therefore, it is considered that the effect is small for the distillation column. That is, in order to lower HETP, it is premised that it is porous, but if the pore size is too small, it is rather inappropriate.

(3) Further, from Table 5, the HETPs of Examples 1 to 4-2 are 22 to 22 of the HETPs of Comparative Example 3 (filling is made of PP (polypropylene) plastic sintered porous body, pore diameter is 200 μm). It is clearly stated that it is 72%. From this, the following matters are derived. That is, when the filler is a porous body of a polymer such as polypropylene, it is derived that it is not suitable for lowering HETP. It is considered that the reason for this is that since the contact angle between water and polypropylene is large, the force for sucking water in the capillary structure is small, and therefore the area where the liquid moves through the capillary structure portion is small. The movement time of the liquid can be shortened by increasing the pore size, but the movement is limited by the action of gravity and other forces.

(4) Further, from Table 5, the HETPs of Examples 1 to 4-2 are 10 to 10 of the HETPs of Comparative Example 4 (filling is made of PP (polypropylene) plastic sintered porous body, pore diameter is 100 μm). It is clearly stated that it is 34%. From this, the following matters are derived. That is, as in Comparative Example 3, when the filler is a porous body of a polymer such as polypropylene, it is derived that it is not suitable for lowering HETP. However, even if the contact angle between water and polypropylene is large, if the pore size is reduced, the force for sucking water in the capillary structure can be increased. However, if the pore size is small, it takes too much time for the liquid to move through the capillary structure portion, which is considered inappropriate for lowering HETP.

(5) From Table 5, the overall conclusion is that the HETP of the filler according to the present invention is 15 to 49% of that of glass beads and 22 to 72% of that of zeolite beads, so that the same performance is required. The filling height of the distillation column can be greatly reduced, and the effect is great.

[Example of the second experiment]
As the second experimental example, the following Example 5 and Comparative Examples 5 and 6 were performed. In this second experimental example, as described below, a stainless steel circular tower container having an inner diameter of 100 mm was used as the packed column. In addition, an irregular filler was used as the filler. It should be noted that the third experimental example described later differs in that a regular filler is used as the filler.

(Example 5)
A "porous aluminum cross" composed of an aluminum sintered body was used as the filler. The "porous aluminum cross shape" is a cross-shaped molded porous aluminum plate (typical size 12.5 mm), and has micropores of about 200 μm on the surface. As the packed tower, a stainless steel circular tower container having an inner diameter of 100 mm was filled with the above-mentioned filling so that the filling height was 41.5 cm. The boiler was prepared by adding 1 kg of heavy water to 55 L of pure water. The operation was set to a predetermined decompression state. The temperature of the boiler was about 65 ° C., and the output of the heater of the boiler was set to 12 kw for steady operation. The distillate amount at this time was about 18.4 l / h (evaporation rate was 2000 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 1.740%
Condensate at the top of the tower; 1.441%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.828

(Comparative Example 5)
With the same equipment as in Example 5, the same operating conditions were adopted, and the filling was filled with "Matsui Cascade Mini Ring" (manufactured by Matsui Machine Co., Ltd.) so that the filling height was 100 cm. When the heavy water concentration was measured by the same measurement method, it was as follows. The "Matsui Cascade Mini Ring" is an irregular filler (typical size 17 mm) that is not porous, and its surface is exposed by shot blast surface treatment.

Boiler concentrate; 1.630%
Condensate at the top of the tower; 1.373%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.842

(Comparative Example 6)
With the same equipment as in Example 5, the same operating conditions are adopted, and the filling is made of ceramic Raschig ring (the surface is coated with zeolite and the representative size is 12.5 mm), which is an irregular filling, and the filling height is 48 cm. When the heavy water concentration was measured by the same measuring method as in Example 5, the results were as follows. The surface of the ceramic raschig ring is coated with zeolite.

Boiler concentrate; 1.706%
Condensate at the top of the tower; 1.468%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.860

(Examination of experimental results in the second experimental example)
From Table 6, it is clarified that the HETP of Example 5 is 36% of the HETP of Comparative Example 5 and 62% of the HETP of Comparative Example 6. For this reason, even in the case of an irregular packing, it is preferable for a filling that is not porous (Comparative Example 5) and a filling that is porous but has a pore size that is too small (Comparative Example 6). It is derived that the "porous aluminum cross" (Example 5) configured by the pore size can lower HETP. It is understood that it is preferable to use an aluminum sintered body as the fine pore forming means.

[Example of the third experiment]
As the third experimental example, the following Example 6 and Comparative Examples 7 and 8 were performed. In this third experimental example, as described below, a stainless steel circular tower container having an inner diameter of 100 mm was used as the packed tower. In addition, a regular filler was used as the filler.

(Example 6)
"Aluminum sprayed Matsui Rule 250S" was used as the filler. "Aluminum sprayed Matsui Rule 250S" is a filler in which an aluminum sprayed layer is provided on the surface of an existing filler ("Matsui Rule 250S" composed of corrugated metal plates), and the surface thereof is approximately. Micropores of about 200 μm are provided. As the packed tower, a stainless steel circular tower container having an inner diameter of 100 mm was filled with the above-mentioned filling so that the filling height was 90 cm. The boiler was prepared by adding 1 kg of heavy water to 55 L of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 65 ° C., and the output of the heater of the boiler was set to 12 kw for steady operation. The distillate amount at this time was about 18.4 l / h (evaporation rate was 2000 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got
In forming the aluminum spraying layer, a known thermal spraying method such as plasma spraying or arc spraying was used.

Boiler concentrate; 1.711%
Condensate at the top of the tower; 1.350%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.789

(Comparative Example 7)
With the same equipment as in Example 6, the same operating conditions are adopted, and the filling material is "Matsui Rule 250S" (manufactured by Matsui Machine Co., Ltd.), which is not sprayed with aluminum, so that the filling height is 90 cm. When the heavy water concentration was measured by the same measuring method as in Example 6, it was as follows.

Boiler concentrate; 1.836%
Condensate at the top of the tower; 1.583%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.863

(Examination of experimental results in the third experimental example)
From Table 7, it is clarified that the HETP of Example 6 is 54% of the HETP of Comparative Example 7. From this, even in the case of a regular filling, the filling having micropores on the surface by aluminum spraying (Example 6) can lower the HETP with respect to the non-porous filling (Comparative Example 7). Is guided. It is understood that it is preferable to form an aluminum sprayed layer by spraying aluminum as a means for forming micropores. Further, comparing Example 5 which is an irregular filling and Example 6 which is an irregular filling, Example 6 which is an irregular filling is preferable from the viewpoint that the pressure loss can be suppressed to a small size. ..

(Summary of experimental conclusions in the first to third experimental examples)
As described above, the HETP of the filler according to the present invention was 15 to 49% of that of the glass beads and 22 to 72% of that of the zeolite beads, so that the filling height of the distillation column requiring the same performance was greatly reduced. The effect is great.

For distillation separation of components with close specific volatility (for example, heavy water and light water, tritium and light water, tritium and heavy water, etc.), how to reduce the filling height is an industrial issue. Conventionally, attempts have been made to make the filler adsorbable to solve this problem. It has been found that the present invention can further enhance the separation effect as compared with the case of the adsorbent by constructing a capillary structure having no adsorptive property but having a large number of pores. The theoretical consideration that such a structure has the effect of enhancing the separation effect is still continuing, but it is considered as follows. That is, the surface of the filler is at the liquid flow rate (270 kg / m ² h to 590 kg / m ² h in the first experimental example and 2000 kg / m ² h in the second and third experimental examples) in which this test was performed. Focusing on one point on the surface, it is presumed that the liquid does not always flow, but the liquid flow is often interrupted, comes into direct contact with the steam, and after a while, the liquid covers the surface again and flows down. When in contact with steam, the liquid remains in the porous portion on the surface, and it is considered that this portion comes into contact with the components in the vapor and approaches the equilibrium concentration of the vapor. Since the flowing liquid comes into contact there, it is considered that the concentration of the flowing liquid is higher than that in the absence of the porosity.

INDUSTRIAL APPLICABILITY The present invention is suitably carried out for a filler used in a distillation column, a distillation separation method using the filler, and a distillation separation device, particularly for distillation separation of a component having a close specific volatilization such as tritium water. It is possible to apply to the distillation separation method and the distillation separation apparatus which can be performed.

1: Distiller 2: Distiller 3: Reboiler 4: Condensator

The present invention relates to a distillation separation method and a distillation separation device using a packed material used in a packed bed, and more particularly to a distillation separation method and a distillation separation device that can be suitably carried out for separation of tritiated water and light water. It is a thing.

In a distillation separation device that uses a packed column as a distillation column, when distillation separation of components with close specific volatility is performed using a conventionally used packing material such as glass beads, the number of stages of the distillation column becomes a practical level. A large number of stages exceeding the number is required. For example, in the case of distillation separation of tritiated water, it has been reported that a reflux ratio of 30 and a theoretical plate number of 230 are required to concentrate the concentration 10 times (see Non-Patent Document 1 below). Here, the number of stages can be reduced by increasing the reflux ratio. However, if an attempt is made to increase the reflux ratio, it is necessary to increase the energy, which leads to an increase in energy cost.

Therefore, in order to solve such a problem, it has been proposed that a packed tower type distillation separation using an adsorbent that selectively adsorbs the component to be distilled-separated as a filler is effective (the following non-distillation). See Patent Document 2). According to this Non-Patent Document 2, when the distillation separation method when silica gel beads are used as a filler is examined, it is presumed that the number of theoretical plates can be 133 with the same reflux ratio.

When a selective adsorbent such as silica gel beads is used as the filler as in the above-mentioned conventional example, the reflux ratio and the number of theoretical plates can be significantly reduced. However, since a high reflux ratio is still required and a special manufacturing method is required for manufacturing the adsorbent, there is a problem that the energy required for operation becomes enormous and the manufacturing cost of the filler becomes high.

On the other hand, in recent years, a filler made of a porous body having continuous ventilation holes having a specific pore diameter inside thereof even if it is not adsorptive has been proposed (see Patent Document 1 below). The filler of Patent Document 1 is, for example, a porous body made of polypropylene, and has an average pore diameter of 80 to 300 μm. In the filler having such a structure, the wet surface area becomes large due to the permeation of the liquid into the inside of the continuous ventilation holes. As a result, it is said that the separation performance can be improved by increasing the gas-liquid contact area.

Publication No. 55-8819

"2009 Evaluation of Tritium Removal and Mitigation Technologies for Wastewater Treatment", DOE / RL-2009-18 "Tritium Isotope Separation by Water Distillation Column Packed with Silica-gel Beads", Journal of NUCLEAR SCIENCE and TECHNOLOGY Vol.41, No.5 pp619-623

However, the above-mentioned porous body made of polypropylene and a filler having continuous ventilation holes having an average pore diameter of 80 to 300 μm has not yet obtained sufficient separation performance. As will be described later in the section of [Example], the HETP (equivalent height per theoretical plate) is a considerably high value according to the experiments by the present inventors, and the filling height is practical. It has been proven that it cannot be lowered to the height of the level.

The present invention has been conceived in view of the above problems, and an object thereof is a distillation separation method and distillation using a filler which is a porous body and can reduce the filling height to a practical level. It is to provide a separator.

The invention according to claim 1 for achieving the above object is a distillation separation method for performing distillation separation of a stock solution to be treated by using a distillation column filled with a filler, wherein the filler is a base material. The surface of the film is covered with an aluminum spray layer, and the filler is composed of a capillary structure. The liquid permeation rate of the capillary structure is as follows: It has a characteristic that the time required to penetrate 10 mm in the horizontal direction in the thin tube calculated using the above is 0.05 seconds or less, and in the undiluted solution, heavy water and light water, tritium and heavy water, or tritium. It is characterized by being used for the separation of light water .

Here, "at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon" means that the entire filler is made of the micropore-forming means and the filler base. It means that the case where the micropore forming means is configured to cover only the surface of the material is included.

According to the above configuration, the liquid penetrating the inside of the micropores seeps out to the surface of the filler due to the action of the capillary phenomenon and diffuses so as to cover the surface of the filler in a short time. Increased and increased mass transfer rate in the distillation column. As a result, the distillation separation method (invention according to claim 1 ) capable of reducing HETP (height equivalent of theoretical plate) and reducing the filling height to a practical level. The distillation separation device (the invention according to claim 4 ) can be realized.

The invention according to claim 2 is the distillation separation method according to claim 1, wherein the filler is composed of a capillary structure, and the capillary force of the capillary structure is approximated by a capillary water column in one capillary. It is characterized by having a characteristic that the height of the capillary water column calculated under the condition of normal temperature water using the following first equation is 0.03 m or more .

The invention according to claim 3 is the distillation separation method according to claim 2 , characterized in that the height of the capillary water column is 0.05 m or more .

The invention according to claim 4 is a distillation separation device provided with a distillation tower filled with a filler, wherein the filler is configured such that the surface of a base material is covered with an aluminum spray layer, and the filling is performed. The material is composed of a capillary structure, and the permeation rate of the liquid in the capillary structure is 10 mm in the horizontal direction calculated by turning one capillary tube sideways and using the following second equation. It has a characteristic that the time required for the distillation is 0.05 seconds or less, and is characterized by being used for separating heavy water and light water, tritium and heavy water, or tritium and light water .

According to the above configuration, it is possible to realize a distillation separation device capable of improving the separation performance and reducing the filling height to a practical level.

According to the present invention, the liquid penetrating into the pores seeps out to the surface of the filler due to the appearance of the capillary phenomenon, and diffuses so as to cover the surface of the filler in a short time, so that the air-liquid contact area increases. And the mass transfer rate in the distillation column is increased. As a result, it is possible to realize a distillation separation method and a distillation separation device that can reduce HETP (height equivalent of theoretical plate) and reduce the filling height to a practical level. be able to.

A graph showing the height of the capillary water column for each combination of material and capillary radius related to the capillary structure. The graph which shows the liquid permeation rate (expressed by the time to advance 10 mm) for each combination of a material and a capillary radius about a capillary structure. Overall configuration diagram of a distillation separation device using a filler composed of a capillary structure for a distillation column.

Hereinafter, the present invention will be described in detail based on the embodiments. The present invention is not limited to the following embodiments.
(Embodiment)
The filler according to the present embodiment is a filler filled in a distillation column to which a treatment liquid is supplied, and is composed of a capillary structure. Here, the "capillary structure" is composed of a porous body having a large number of pores, and the liquid that permeates the pores seeps out to the surface of the filler due to the action of the capillary phenomenon, and the surface of the filler is exposed. It means a structure configured so that a state of diffusion so as to cover in a short time can occur. Here, the "pore" means a minute cavity contained in a group of objects, and includes an open pore connected to the outside air and a closed pore isolated inside the object. "Void" means a minute cavity contained in a group of objects, including open pores connected to the outside air and closed pores isolated inside the object. Further, here, "short time" means that the liquid flowing down the surface of the filler enters the pores and is temporarily interrupted at the position, and at least until the subsequent flowing liquid passes from the interrupted state at the position. It means an extremely short time during which the liquid penetrating the pores diffuses so as to cover the surface of the filler and is allowed to come into contact with the subsequent flowing liquid. The specific meaning of "short time" is explained in paragraph 1981 of [Example] described later.

Further, as a specific configuration of the capillary structure, the height of the capillary water column is at least a predetermined value, and the permeation rate at which the liquid permeates the inside of the capillary structure is at least a predetermined value. It is necessary that the time required to penetrate the predetermined length is less than or equal to the predetermined time). Here, by limiting the height of the capillary water column to a predetermined value or more, the material and pore diameter of the porous body for obtaining the capillary force required for the capillary structure are determined as described later. The material and pore size of the porous body for obtaining the fluidity of the liquid required for the capillary structure are determined by the limitation that the permeation rate at which the liquid permeates the inside of the capillary structure is a predetermined value or more.

Hereinafter, the background to the present embodiment will be described first, and then the specific concept of the height of the capillary water column of the capillary structure and the specific concept of the liquid permeation rate of the capillary structure will be described in detail.

[Background to the embodiment]
When the present inventors provide a space inside the structure to the extent that the capillary force acts, the liquid spreads to all surfaces by the capillary force, and as a result, the force that the liquid covers the entire surface of the filler acts. However, it has been found that a gas-liquid contact device using this force significantly increases the mass transfer rate.
Conventionally, a surface treatment for improving the wettability of the surface of the filler (for example, physical sand blasting or chemical surface treatment when a stainless steel material is used especially in an aqueous system) is performed. However, although these are intended to reduce the contact angle with the liquid (especially in the case of water) and improve the wettability, the wet area is inevitably limited to a certain proportion of the physical surface area as long as the contact angle exists. , The area is much smaller than the physical surface area for which a predictive formula has been proposed.

For example, the calculation as an example of a regular filling is as follows. Several model formulas of this type have been proposed, but here we used the SRP model (abbreviation of University of Texas Separation Research Program :) that includes the contact angle element.

Here, by substituting the condition values in Table 1 below into the numbers 3 to 8,

Even if the contact angle of the filling surface could be improved to 50 ° by trying to improve the wettability, the value remains at 0.14, especially when the superficial velocity of the liquid is small (5 m ³ / m). (Like ^2h ) shows how many areas are not working effectively.
Therefore, if the filler to be filled in the distillation column is composed of a capillary structure, the present inventors spread the liquid to all surfaces by the capillary force, and as a result, the liquid covers the entire surface of the filler. I found that force works. For example, if the contact angle between the constituent material and water is the same, the capillary force increases as the pore diameter becomes smaller. However, the filler used in the distillation column is not effective simply because it has a capillarity. The present inventors have found that the speed at which the liquid flows in the capillary tube is an important factor. As a result, HETP (height equivalent of theoretical plate) can be reduced by increasing the gas-liquid contact area and the mass transfer rate in the distillation column, and the filling height can be set to a practical level. Can be lowered to height.

[Capillary water column height of capillary structure]
The height of the capillary water column is an index for evaluating the capillary force of the capillary structure. Specifically, the capillary force is approximately expressed by the capillary water column in one capillary tube, and is based on the following number 8. The water used is at room temperature.

Here, θ (contact angle) and the capillary radius r adopt the values in Table 2 below, and the capillary water column height is calculated using the number 8 for each combination of the constituent material and the capillary radius r, and the calculation result is obtained. It is shown in Table 3. In addition, the height of each capillary water column shown in Table 3 is shown as a graph in FIG. In FIG. 1, the height of the capillary water column in the glass beads (r = 10 μm), the cellulose capillary structure (r = 10 μm), the plastic capillary structure (r = 5 μm) and the ceramic capillary structure (r = 35 μm) is , All of them are values outside the frame, so they are drawn up to 0.3m.

In FIG. 1, glass beads have a capillary radius of 500 μm, an aluminum capillary structure has a capillary radius of 330 μm, plastic has a capillary radius of 100 μm, a ceramic capillary structure has a capillary radius of 390 μm, and a stainless steel capillary structure has a capillary radius of 180 μm, or copper. When the capillary structure has a capillary radius of 270 μm, the height of the capillary water column is about 0.03 m. Further, when the plastic has a capillary radius of 50 μm, the height of the capillary water column is about 0.05 m. In the other cases in FIG. 1, the height of the capillary water column is much larger than about 0.05 m. Therefore, as the capillary force of the capillary structure, it is preferable that the height of the capillary water column is at least 0.03 m or more, and more preferably 0.05 m or more. It is proved by Examples and Comparative Examples to be described later that the capillary structure having 0.03 m or more, more preferably 0.05 m or more, reduces HETP (theoretical stage equivalent height) (more accurately explained). In addition to the condition of having 0.03 m or more, more preferably 0.05 m or more, there is also a condition that the time (seconds) for advancing 10 mm, which will be described later, is within 0.1 seconds, more preferably within 0.05 seconds. Proof when added).

[Liquid permeation rate of capillary structure]
The liquid permeation rate of the capillary structure is expressed by the expression that the time required for the liquid to permeate a predetermined length is not more than a predetermined time.

Even if the capillary structure is the same, if the void size is too small, the fluidity due to the capillary phenomenon decreases due to the flow friction, and the mass transfer rate of the packed column is decreased. Therefore, it is considered that the flow of the liquid expands in the capillary structure because the capillary force and the frictional resistance flowing through the capillary become equal, and the time for tentatively penetrating 10 mm in the horizontal direction is calculated by the following equation 9. It is shown in Table 4 below. This Table 4 shows the time (seconds) to travel 10 mm calculated for each combination of the same material and capillary radius as in Table 3. In addition, the time (seconds) for advancing each 10 mm shown in Table 4 is shown as a graph in FIG. In FIG. 2, the time (seconds) in the plastic capillary structure (r = 5 μm) is a value outside the frame, so it is drawn up to 1.2 seconds.
In addition, although the number 12 is shown in the literature as the Lucas-Washburn formula, the capillary flow is analyzed using the Hagen-Poiseuille flow formula using the one obtained by converting the capillary force into the pressure difference. ..

This indicates that the flow velocity when the liquid flows inside the structure due to the capillary force is related to the mass transfer velocity of the packed column. Even if the capillary force is large, the structure in which the liquid permeates is fine, and the structure in which the permeation rate is slow is ineffective or small in increasing the mass transfer rate. Distillation separation tests using various packed materials have shown that this time is within 0.1 seconds, more preferably within 0.05 seconds for permeating 10 mm, for mass transfer rates in packed beds. It was found to be effective in increasing.

Specifically, in FIG. 2, the glass beads have a capillary radius of 10 μm, the aluminum capillary structure has a capillary radius of 40 μm, the cellulose capillary structure has a capillary radius of 10 μm, the plastic capillary structure has a capillary radius of 5 μm, and the plastic capillary structure. When the capillary radius is 50 μm, the capillary radius is 100 μm in the plastic capillary structure, or the capillary radius is 35 μm in the ceramic capillary structure, the time required is 0.1 seconds or more. If the glass beads have a capillary radius of 50 μm, the aluminum capillary structure has a capillary radius of 50 μm, the stainless capillary structure has a capillary radius of 75 μm, or the copper capillary structure has a capillary radius of 50 μm, the time required is 0.05 seconds or longer. Is. In the other cases in FIG. 2, the time required is much smaller than 0.05 seconds. Therefore, the permeation rate of the capillary structure is preferably at least 0.1 seconds or less, and more preferably 0.05 seconds or less. It is proved by Examples and Comparative Examples to be described later that the capillary structure having a time of 0.1 seconds or less, more preferably 0.05 seconds or less, reduces HETP (theoretical stage equivalent height) (more accurately explained). Therefore, in addition to the condition that the height is within 0.1 seconds, more preferably within 0.05 seconds, the height of the capillary water column is preferably 0.03 m or more, more preferably 0.05 m or more. It is proved when the condition of having is also added).

[Specific example of preferable capillary structure]
A capillary structure satisfying the above conditions of [capillary water column height of capillary structure] and [liquid permeation rate of capillary structure] is preferable. In consideration of industrial production, it is preferable to use ceramic, stainless steel, aluminum, or copper as the material. From such conditions, as a specific preferable capillary structure, the pore diameter is 70 μm (corresponding to the capillary radius r = 35) or more, 800 (corresponding to the capillary radius r = 400, and r = 390 in the above example. ) Μm or less ceramic capillary structure, pore diameter 150 μm (corresponding to capillary radius r = 75), 400 (corresponding to capillary radius r = 200, r = 180 is used in the above example) μm or less Stainless steel capillary structure, aluminum capillary structure with pore diameter of 80 μm (corresponding to capillary radius r = 40) and 700 (corresponding to capillary radius r = 350, r = 330 is used in the above example) μm or less , And a copper capillary structure having a pore diameter of 100 μm (corresponding to a capillary radius r = 50) and 500 (corresponding to a capillary radius r = 250, r = 270 is used in the above example) μm or less.

[Application example of distillation separation device]
FIG. 3 is an overall configuration diagram of a distillation separation device using a filler made of a capillary structure in a distillation column. The undiluted solution supplied to the distillation separation device 1 is light water (H ₂ O) containing tritiated water (HTO or T ₂ O). In this distillation separation device 1, light water (H ₂ O) containing tritiated water (HTO or T ₂ O) is separated into tritiated water having a higher concentration than the undiluted solution and tritiated water having a lower concentration than the undiluted solution. used.

The distillation separation device 1 cools the refillable multi-stage distillation column 2, the reboiler 3 that heats and vaporizes the stored liquid at the bottom of the distillation column 2, and the steam supplied from the top of the distillation column 2. A condenser 4 for liquefying, a reflux tank 5 for storing the condensed liquid from the condenser 4, and a pump 6 provided on the reflux line L1 for refluxing the condensed liquid from the bottom of the reflux tank 5 to the top of the distillation column 2. , A control valve V1 provided on the reflux line L1 and a cooling tank 7 as a supply source of cooling water supplied to the condenser 4. As the filler of the distillation column 2, a filler made of a capillary structure is used. The bleed air of the condenser 4 is connected to a vacuum pump (not shown) provided separately, and the inside of the distillation column 2 is evacuated by this vacuum pump. Further, the operating temperature is controlled to a predetermined value by adjusting the degree of vacuum of the vacuum pump.

The distillation separation device 1 is provided with a thermometer, a pressure gauge, and a flow meter, if necessary. Examples of the thermometer, pressure gauge and flow meter include a thermometer T1 and a pressure gauge P1 provided at the top of the distillation tower 2, a thermometer T2 and a pressure gauge P2 provided at the bottom of the distillation tower 2, and a reflux line L1. F1, thermometer T3 and flow meter F2 provided in the cooling water flow line L2, thermometer T4 provided in the cooling water return line L3, and recirculation. Examples thereof include a thermometer T5 provided in the tank 5.

The operation of the distillation separation device 1 having the above configuration is the same as that of a general distillation separation device. Briefly described below, the undiluted solution is supplied from the central portion of the distillation column 2, flows down in the distillation column 2, and is heated by the reboiler 3 at the bottom of the distillation column 2 to generate steam. The generated steam rises in the distillation column 2 and undergoes gas-liquid contact with the undiluted solution descending in the distillation column 2. At this time, since the filler is a capillary structure, a state in which the liquid diffuses so as to cover the entire surface of the filler is exhibited. As a result, the gas-liquid contact area is increased, gas-liquid contact can be performed on more contact surfaces, and the separation performance is improved.

Then, in the process of this gas-liquid contact, the tritium concentration in the descending liquid increases, and the tritium concentration in the ascending steam decreases. Then, the rising steam after the gas-liquid contact reaches the top of the column and is further guided to the condenser 4. In the condenser 4, the supplied steam is cooled by the cooling water, and a part of the steam is returned to the top of the column (reflux) through the reflux tank 5, and a part of the steam is discharged as low-concentration tritiated water having a lower tritiated concentration than the undiluted solution. Is discharged from. On the other hand, the descending liquid after the gas-liquid contact is stored in the bottom of the column, and a part of this stored liquid is recovered from the discharge line L5 as high-concentration tritiated water having a higher tritiated concentration than the undiluted solution.

(Other matters)
(1) The pores of the capillary structure may be communication holes or independent holes.

(2) It is preferable that the surface of the capillary structure is hydrophilized.

(3) The filler may be a columnar bead or a spherical bead, and may be a regular filler or an irregular filler having appropriate pressure loss characteristics, which is often used in an actual device. , A filler having a porous surface thereof may be adopted, or a porous material may be supported on the surface. Even with such a configuration, the same effect can be achieved.

(4) In the above embodiment, tritiated water is used as the "liquid (stock solution) to be treated", but the present invention is not limited to this, and heavy water and other isotopes having close specific volatility are used. It can also be applied to the separation of the body.

(5) The distillation separation device is not limited to the above embodiment, but is provided with a steam compressor that functions as a heat pump, and the steam from the top of the distillation column is reused as a heating source for the reboiler using the steam compressor. It may be an energy-saving type distillation separation device.

(6) As the filler (corresponding to the capillary structure) in the above embodiment, at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon, and the micropore-forming means is a metal. It may be a sprayed layer or a metal sintered body. Here, "at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon" means that the entire filler is made of the micropore-forming means and the filler base. It means that the case where the micropore forming means is configured to cover only the surface of the material is included.

Further, the metal sprayed layer is preferably an aluminum sprayed layer. As a filler using an aluminum sprayed layer, "Aluminum sprayed Matsui Rule 250S" (corresponding to Example 6 described later) is exemplified.

Further, the metal sintered body is preferably an aluminum sintered body. As a filler using an aluminum sintered body, a “porous aluminum cross shape” (corresponding to Example 5 described later) composed of an aluminum sintered body is exemplified.

Here, it is proved by the third experimental example described later that the filler using the aluminum sprayed layer can reduce the HETP (height equivalent to the theoretical stage) and the filler height to a practical level. Has been done. Further, it is proved by the second experimental example described later that the filler using the aluminum sintered body can reduce HETP (height equivalent to the theoretical stage) and reduce the filler height to a practical level. Has been done.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples. In the following examples and comparative examples, the same as the above embodiment except that the size of the distillation column (the body diameter of the actual distillation column as in the embodiment is several m level) is different. Distillation separation was performed using the undiluted solution as heavy water using various fillers having different materials and pore diameters using a test distillation separation device having a configuration.

[Example of the first experiment]
As the first experimental example, the following Examples 1 to 4 and Comparative Examples 1 to 4 were performed. In this first experimental example, as described below, a glass column having an inner diameter of 18 mm was used as the packed column.

(Example 1)
Alumina columnar beads (Product No. R-200 manufactured by Nishimura Ceramics Co., Ltd.) having a diameter of 0.34 cm and a length of 0.4 cm were used as the filler. Micropores of about 10 μm are provided on this surface.
The packed tower used was a glass column having an inner diameter of 18 mm filled with the above-mentioned filler so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 70 to 75 W for steady operation. The distillate amount at this time was about 150 ml / h (evaporation rate was 590 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 0.699%
Condensate at the top of the tower; 0.563%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.81

(Example 2)
Cellulose porous beads (trade name: Biscopearl P type, Rengo Co., Ltd.) having a diameter of 0.3 to 0.4 cm were used as a filler. Micropores of about 20 to 30 μm are provided on this surface. The packed tower used was a glass column having an inner diameter of 18 mm filled with the above filling so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 60 to 65 W for steady operation. The distillate amount at this time was about 150 ml / h (evaporation rate was 590 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 0.828%
Condensate at the top of the tower; 0.629%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.76

(Example 3)
As the filler, porous glass beads (manufactured by ROBU), which is a sintered body of glass having a diameter of 0.3 to 0.4 cm, were used. Micropores of about 40 to 100 μm are provided on this surface. The packed tower used was a glass column having an inner diameter of 18 mm filled with the above-mentioned filler so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 60 to 65 W for steady operation. The distillate amount at this time was about 80 ml / h (evaporation rate was 300 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensate at the top of the column with a gas chromatograph, and the following data Got

Boiler concentrate; 0.980%
Condensate at the top of the tower; 0.523%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.53

(Example 4)
As a filler, a porous alumina plate (manufactured by NDC Sales Co., Ltd.), which is a sintered body of aluminum, was processed into pellets having a diameter of 0.3 to 0.4 cm and used. Micropores of about 200 μm are provided on this surface. The packed tower used was a glass column having an inner diameter of 18 mm filled with the above filling so that the filling height was approximately 50 cm to 60 cm. The boiler was prepared by adding 2.0 ml of heavy water to 300 ml of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 100 ° C., and the output of the heater of the boiler was set to 60 to 65 W for steady operation. The distillate amount at this time was about 70 ml / h (evaporation rate was 270 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 0.771%
Condensate at the top of the tower; 0.482%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.63

(Example 4-2)
The filler used in Example 4 was subjected to a hydrophilic treatment (boehmite treatment) to improve the wettability of the surface, and the same test as in Example 4 was carried out using the filler subjected to the hydrophilic treatment. gone.
Boiler concentrate; 0.753%
Condensate at the top of the tower; 0.436%
Separation coefficient (tower concentration ÷ boiler concentration) = 0.58

(Comparative Example 1)
Using the same equipment as in the examples, the same operating conditions were adopted, glass beads (4 mmφ) without micropores were filled in the filler at the same filling height, and the heavy water concentration was measured in the same manner as follows.

Boiler concentrate; 0.792
Condensate at the top of the tower; 0.703
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.89

(Comparative Example 2)
Using the same equipment as in the examples, using the same operating conditions, the filler is filled with zeolite beads (Union Showa product number MS-13X, 3-4 mmφ) at the same filling height, and the heavy water concentration is measured in the same manner. It became as follows.

Boiler concentrate; 0.967
Condensate at the top of the tower; 0.844
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.87

(Comparative Example 3)
Using the same equipment as in the examples, the same operating conditions were adopted, and the filler was filled with a PP (polypropylene) plastic sintered porous body and a pore diameter of 200 μm (Fuji Chemical thickness 4 mm) at the same filling height. The measurement of heavy water concentration was as follows.

Boiler concentrate; 0.785
Condensate at the top of the tower; 0.691
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.88

(Comparative Example 4)
With the same equipment as in the examples, the same operating conditions were adopted, and the filler was filled with a PP (polypropylene) plastic sintered porous body, a pore diameter of 100 μm (Fuji Chemical thickness 4 mm) at the same filling height, and similarly heavy water. The concentration was measured as follows.
Boiler concentrate; 0.726
Condensate at the top of the tower; 0.785
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.93

Here, the HETP (height equivalent to the theoretical stage) of the distillation column was calculated in the above-mentioned Example and the above-mentioned Comparative Example, and the results are shown in Table 5 below. However, the specific volatility of heavy water at 100 ° C. was 0.975.

The following formula was used to calculate HETP.
HETP = Z / N
N = {Log (Separation Factor) / Log (α)} -1
However, Separation Factor: Separation coefficient α: Specific volatility Z: Packed bed height [m]

(Examination of experimental results in the first experimental example)
(1) From Table 5, it is clarified that the HETP of Examples 1 to 4-2 is 15 to 49% of the HETP of Comparative Example 1 (glass beads whose filling is no pores). This leads to the fact that HETP can be lowered depending on the presence or absence of pores in the packing.

(2) Further, from Table 5, it is clarified that the HETP of Examples 1 to 4-2 is 22 to 72% of the HETP of Comparative Example 2 (filling is zeolite beads). From this, the following matters are derived. That is, the zeolite beads are also porous like the fillers of Examples 1 to 4-2, but their pore size is, for example, 0.15 to 0.43 μm, and the cavity portion having a too porous structure is formed. Because it is small, it takes too much time to move the liquid. Therefore, it is considered that the effect is small for the distillation column. That is, in order to lower HETP, it is premised that it is porous, but if the pore size is too small, it is rather inappropriate.

(3) Further, from Table 5, the HETPs of Examples 1 to 4-2 are 22 to 22 of the HETPs of Comparative Example 3 (filling is made of PP (polypropylene) plastic sintered porous body, pore diameter is 200 μm). It is clearly stated that it is 72%. From this, the following matters are derived. That is, when the filler is a porous body of a polymer such as polypropylene, it is derived that it is not suitable for lowering HETP. It is considered that the reason for this is that since the contact angle between water and polypropylene is large, the force for sucking water in the capillary structure is small, and therefore the area where the liquid moves through the capillary structure portion is small. The movement time of the liquid can be shortened by increasing the pore size, but the movement is limited by the action of gravity and other forces.

(4) Further, from Table 5, the HETPs of Examples 1 to 4-2 are 10 to 10 of the HETPs of Comparative Example 4 (filling is made of PP (polypropylene) plastic sintered porous body, pore diameter is 100 μm). It is clearly stated that it is 34%. From this, the following matters are derived. That is, as in Comparative Example 3, when the filler is a porous body of a polymer such as polypropylene, it is derived that it is not suitable for lowering HETP. However, even if the contact angle between water and polypropylene is large, if the pore size is reduced, the force for sucking water in the capillary structure can be increased. However, if the pore size is small, it takes too much time for the liquid to move through the capillary structure portion, which is considered inappropriate for lowering HETP.

(5) From Table 5, the overall conclusion is that the HETP of the filler according to the present invention is 15 to 49% of that of glass beads and 22 to 72% of that of zeolite beads, so that the same performance is required. The filling height of the distillation column can be greatly reduced, and the effect is great.

[Example of the second experiment]
As the second experimental example, the following Example 5 and Comparative Examples 5 and 6 were performed. In this second experimental example, as described below, a stainless steel circular tower container having an inner diameter of 100 mm was used as the packed column. In addition, an irregular filler was used as the filler. It should be noted that the third experimental example described later differs in that a regular filler is used as the filler.

(Example 5)
A "porous aluminum cross" composed of an aluminum sintered body was used as the filler. The "porous aluminum cross shape" is a cross-shaped molded porous aluminum plate (typical size 12.5 mm), and has micropores of about 200 μm on the surface. As the packed tower, a stainless steel circular tower container having an inner diameter of 100 mm was filled with the above-mentioned filling so that the filling height was 41.5 cm. The boiler was prepared by adding 1 kg of heavy water to 55 L of pure water. The operation was set to a predetermined decompression state. The temperature of the boiler was about 65 ° C., and the output of the heater of the boiler was set to 12 kw for steady operation. The distillate amount at this time was about 18.4 l / h (evaporation rate was 2000 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got

Boiler concentrate; 1.740%
Condensate at the top of the tower; 1.441%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.828

(Comparative Example 5)
With the same equipment as in Example 5, the same operating conditions were adopted, and the filling was filled with "Matsui Cascade Mini Ring" (manufactured by Matsui Machine Co., Ltd.) so that the filling height was 100 cm. When the heavy water concentration was measured by the same measurement method, it was as follows. The "Matsui Cascade Mini Ring" is an irregular filler (typical size 17 mm) that is not porous, and its surface is exposed by shot blast surface treatment.

Boiler concentrate; 1.630%
Condensate at the top of the tower; 1.373%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.842

(Comparative Example 6)
With the same equipment as in Example 5, the same operating conditions are adopted, and the filling is made of ceramic Raschig ring (the surface is coated with zeolite and the representative size is 12.5 mm), which is an irregular filling, and the filling height is 48 cm. When the heavy water concentration was measured by the same measuring method as in Example 5, the results were as follows. The surface of the ceramic raschig ring is coated with zeolite.

Boiler concentrate; 1.706%
Condensate at the top of the tower; 1.468%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.860

(Examination of experimental results in the second experimental example)
From Table 6, it is clarified that the HETP of Example 5 is 36% of the HETP of Comparative Example 5 and 62% of the HETP of Comparative Example 6. For this reason, even in the case of an irregular packing, it is preferable for a filling that is not porous (Comparative Example 5) and a filling that is porous but has a pore size that is too small (Comparative Example 6). It is derived that the "porous aluminum cross" (Example 5) configured by the pore size can lower HETP. It is understood that it is preferable to use an aluminum sintered body as the fine pore forming means.

[Example of the third experiment]
As the third experimental example, the following Example 6 and Comparative Examples 7 and 8 were performed. In this third experimental example, as described below, a stainless steel circular tower container having an inner diameter of 100 mm was used as the packed column. In addition, a regular filler was used as the filler.

(Example 6)
"Aluminum sprayed Matsui Rule 250S" was used as the filler. "Aluminum sprayed Matsui Rule 250S" is a filler in which an aluminum sprayed layer is provided on the surface of an existing filler ("Matsui Rule 250S" composed of corrugated metal plates), and the surface thereof is approximately. Micropores of about 200 μm are provided. As the packed tower, a stainless steel circular tower container having an inner diameter of 100 mm was filled with the above-mentioned filling so that the filling height was 90 cm. The boiler was prepared by adding 1 kg of heavy water to 55 L of pure water. The operation was set to atmospheric pressure. The temperature of the boiler was about 65 ° C., and the output of the heater of the boiler was set to 12 kw for steady operation. The distillate amount at this time was about 18.4 l / h (evaporation rate was 2000 kg / m ² h). The steam flowing out from the top of the tower was cooled by a cooler, and the entire amount of condensed water was allowed to flow down from the top of the tower. Maintain 2 hours until steady operation is obtained, and after 4 hours have passed after that, measure the heavy water concentration at the bottom of the boiler and the heavy water concentration of the condensed liquid at the top of the boiler with a gas chromatograph, and the following data Got
In forming the aluminum spraying layer, a known thermal spraying method such as plasma spraying or arc spraying was used.

Boiler concentrate; 1.711%
Condensate at the top of the tower; 1.350%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.789

(Comparative Example 7)
With the same equipment as in Example 6, the same operating conditions are adopted, and the filling material is "Matsui Rule 250S" (manufactured by Matsui Machine Co., Ltd.), which is not sprayed with aluminum, so that the filling height is 90 cm. When the heavy water concentration was measured by the same measuring method as in Example 6, it was as follows.

Boiler concentrate; 1.836%
Condensate at the top of the tower; 1.583%
Separation coefficient (tower top concentration ÷ boiler concentration) = 0.863

(Examination of experimental results in the third experimental example)
From Table 7, it is clarified that the HETP of Example 6 is 54% of the HETP of Comparative Example 7. From this, even in the case of a regular filling, the filling having micropores on the surface by aluminum spraying (Example 6) can lower the HETP with respect to the non-porous filling (Comparative Example 7). Is guided. It is understood that it is preferable to form an aluminum sprayed layer by spraying aluminum as a means for forming fine pores. Further, comparing Example 5 which is an irregular filling and Example 6 which is an irregular filling, Example 6 which is an irregular filling is preferable from the viewpoint that the pressure loss can be suppressed to a small size. ..

(Summary of experimental conclusions in the first to third experimental examples)
As described above, the HETP of the filler according to the present invention was 15 to 49% of that of the glass beads and 22 to 72% of that of the zeolite beads, so that the filling height of the distillation column requiring the same performance was greatly reduced. The effect is great.

For distillation separation of components with close specific volatility (for example, heavy water and light water, tritium and light water, tritium and heavy water, etc.), how to reduce the filling height is an industrial issue. Conventionally, attempts have been made to make the filler adsorbable to solve this problem. It has been found that the present invention can further enhance the separation effect as compared with the case of the adsorbent by constructing a capillary structure having no adsorptive property but having a large number of pores. The theoretical consideration that such a structure has the effect of enhancing the separation effect is still continuing, but it is considered as follows. That is, the surface of the filler is at the liquid flow rate (270 kg / m ² h to 590 kg / m ² h in the first experimental example and 2000 kg / m ² h in the second and third experimental examples) in which this test was performed. Focusing on one point on the surface, it is presumed that the liquid does not always flow, but the liquid flow is often interrupted, comes into direct contact with the steam, and after a while, the liquid covers the surface again and flows down. When in contact with steam, the liquid remains in the porous portion on the surface, and it is considered that this portion comes into contact with the components in the vapor and approaches the equilibrium concentration of the vapor. Since the flowing liquid comes into contact there, it is considered that the concentration of the flowing liquid is higher than that in the absence of the porosity.

The present invention can be suitably applied to a distillation separation method using a filler used in a distillation column and a distillation separation device, particularly for distillation separation of components having close specific volatility such as trithium water. It can be applied to various distillation separation methods and distillation separation devices.

1: Distiller 2: Distiller 3: Reboiler 4: Condensator

Claims (5)

It is a filler filled in the distillation column to which the treatment liquid is supplied.
A filler characterized in that at least the surface is covered with a micropore-forming means made of a porous material that exhibits a capillary phenomenon, and the micropore-forming means is a metal sprayed layer or a metal sintered body. The filler according to claim 1, wherein the metal sprayed layer is an aluminum sprayed layer. The filler according to claim 1, wherein the metal sintered body is an aluminum sintered body. A distillation separation method, which comprises performing distillation separation of a stock solution to be treated by using a distillation column filled with the filler according to any one of claims 1 to 3. It is a distillation separation device equipped with a distillation column.
The distillation column is a distillation separation device, wherein the distillation column is filled with the filler according to any one of claims 1 to 3.

Images