Moisture removal device and moisture removal method

Abstract

To provide a moisture removal device and the like that efficiently remove moisture of a moisture-containing liquid.SOLUTION: A moisture-containing liquid filled into a container is irradiated with microwaves, and a distance between a surface of the liquid filled into the container, and an emission part for emitting microwaves is held at a predetermined distance.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a water removal device for removing water from a liquid containing water.

Background Art

[0002] In some nuclear reactors, an ice condenser in which a plurality of block ice is stored is installed to condense high-temperature steam that fills the reactor containment vessel during abnormal times. As disclosed in Patent Document 1, the block ice is, for example, composed of ice containing borax (Na2B4O7·10H2O) to promote neutron absorption in the main body, and a water-soluble polymer polyvinyl alcohol (PVA) for preventing or suppressing sublimation of the block ice main body is adhered to the outer periphery thereof.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When decommissioning a nuclear reactor in which an ice condenser is installed, it is necessary to remove the water from the liquid formed by thawing the block ice to which PVA is adhered, and properly dispose of the remaining PVA and borax.

[0005] Therefore, an object of this invention is to provide a water removal device or the like that can efficiently remove water from a liquid containing water.

Means for Solving the Problems

[0006] This invention has been made to achieve the above object, and is characterized by the following.

[0007] The invention according to claim 1 is characterized by comprising: irradiation means for irradiating microwaves onto a liquid containing moisture contained in a container; the surface of the liquid contained in the container; and distance holding means for holding the distance between the surface of the liquid and the emission part that emits the microwaves in the irradiation means at a predetermined distance.

[0008] The invention according to claim 2 is a moisture removal device according to claim 1, characterized by comprising: a storage for storing the container; and discharge means for discharging water vapor in the storage from the storage.

[0009] The invention according to claim 3 is a moisture removal device according to claim 1 or 2, characterized in that the distance holding means is a spring that supports the container.

[0010] The invention according to claim 4 is a moisture removal device according to claim 1 or 2, characterized in that the distance holding means is a float provided on the emission part and floating on the liquid, and the float is sized such that when floating on the liquid, the distance between the surface of the liquid and the emission part becomes the predetermined distance.

[0011] The invention according to claim 5 is a moisture removal device according to claim 1 or 2, characterized in that the container forms a communication pipe together with another second container, and the distance holding means supplies the liquid to the second container according to the amount of the liquid in the container decreased due to evaporation of the liquid.

[0012] The invention according to claim 6 is a moisture removal device according to claim 1 or 2, characterized in that the distance holding means is a jack, and the jack lifts the container according to the amount of the liquid in the container decreased due to evaporation of the liquid.

[0013] The invention according to claim 7 is a moisture removal device according to claim 2, characterized by comprising heating means for heating and thawing a solid to obtain the liquid, and the heating means heats using the heat of the water vapor discharged by the discharge means.

[0014] The invention according to claim 8 is a water removal device according to claim 1 or 2, further comprising preheating means for heating the liquid before the irradiation means irradiates the microwave.

[0015] The invention according to claim 9 includes an irradiation step of irradiating a liquid containing moisture in a container with microwaves, and a distance holding step of holding the distance between the surface of the liquid in the container and the emitting portion that emits the microwaves in the irradiation step at a predetermined distance.

Advantages of the Invention

[0016] According to this invention, when evaporating the moisture in a liquid by irradiating microwaves, it is possible to continuously irradiate the microwaves while maintaining the distance between the microwave emitting portion and the liquid surface at a predetermined distance, and by setting the predetermined distance to an optimal distance for evaporating the moisture, the moisture in the liquid can be efficiently removed.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0018] Embodiments of this invention will be described with reference to the drawings. In this embodiment, an example of removing the moisture of the liquid formed by thawing the block ice used in the nuclear reactor will be described. Note that this invention can also be applied to liquids containing moisture other than the liquid formed by thawing the block ice.

[0019] First, the block ice will be described. The block ice is cylindrical, and its main body is composed of ice containing borax (Na2B4O7·10H2O) to promote the absorption of neutrons. A water-soluble polymer polyvinyl alcohol is adhered to the outer periphery of the ice to prevent or suppress the sublimation of the ice. The film made of PVA is adhered to the outer surface of the ice by full-surface welding or partial welding by heat treatment with a dryer or the like. Note that the film made of PVA is preferably a product with a PVA polymerization degree = 1700, a saponification degree = 88 mol%, 0.8 wt% borax added, and a thickness of about 15 μm.

[0020] Next, the basic configuration of the moisture removal device A will be described with reference to FIG. 1. The moisture removal device A includes a storage 1 in which a container 2 containing a liquid W is stored, a waveguide 3 (an example of "irradiation means") that irradiates the liquid W with microwaves M oscillated by a microwave oscillator (not shown), a base 4 that supports the container 2, an air supply port 5 for supplying air to the storage 1, and an exhaust port 6 for discharging the water vapor S in the storage 1 to the outside of the storage 1.

[0021] The waveguide 3 has an emission part 3A that emits microwaves M. The microwaves M emitted from the emission part 3A vibrate the moisture (water molecules) in the liquid W, generating heat and causing evaporation, thereby removing the moisture in the liquid W. When the moisture in the liquid W evaporates, the amount of water vapor in the storage chamber 1 increases, and the removal efficiency of the moisture in the liquid W decreases. Therefore, air (preferably dry air) is supplied from the air supply port 5 by an air supply fan (not shown), and the water vapor S is exhausted from the exhaust port 6 by an exhaust fan (not shown) (an example of "exhaust means"), thereby reducing the amount of water vapor in the storage chamber 1.

[0022] The frequency of the microwaves M is preferably 500 kHz to 6 GHz (wavelength 5 cm to 60 m). Also, by setting the distance h between the emission part 3A and the surface of the liquid W to a predetermined distance that is optimal for evaporating the moisture in the liquid W, the moisture in the liquid W can be efficiently removed. This predetermined distance is set based on factors such as the size and material of the container 2 and the frequency of the microwaves M. Therefore, the moisture removal device A in Examples 1-4 described later includes a distance holding mechanism (an example of "distance holding means") that holds the distance h at a predetermined distance.

[0023] [Example 1] The moisture removal device A in Example 1 will be described with reference to FIG. 2. FIG. 2(A) is a diagram showing the state before the irradiation of the microwaves M (t = t0), and FIG. 2(B) is a diagram showing the state after a certain period of time has elapsed since the start of the irradiation of the microwaves M (t = t1). In Example 1, the description will focus on the points different from the moisture removal device A shown in FIG. 1, and the description of the same configuration will be omitted.

[0024] The moisture removal device A of Example 1 has a spring base 11 instead of the base 4. The spring base 11 includes a spring 11A (an example of "distance holding means") and a mounting plate 11B on which the container 2 is placed. The spring base 11 holds the distance h at a predetermined distance by raising the container 2 with the force of the spring 11A in response to the evaporation of the moisture in the liquid W and the consequent lowering of the surface (liquid level) of the liquid W with respect to the container 2 (the decrease in the weight of the liquid W).

[0025] In FIG. 2, the spring 11A is disposed below the container 2, and the distance h is maintained at a predetermined distance by utilizing the force of the spring 11A, which is compressed by the weight of the container 2 and the liquid W, to return to its original state. Instead of this, one end of the spring 11A may be attached to the ceiling of the storage 1, the other end of the spring 11A may be attached to the mounting plate 11B (or the container 2), and the distance h may be maintained at a predetermined distance by utilizing the force of the spring 11A, which is extended by the weight of the container 2 and the liquid W, to return to its original state.

[0026] [Example 2] The moisture removal device A in Example 2 will be described with reference to FIG. 3. FIG. 3(A) is a diagram showing the state before the irradiation of the microwave M (t = t0), and FIG. 3(B) is a diagram showing the state after a certain period of time has elapsed since the start of the irradiation of the microwave M (t = t1). Note that the description will focus on the differences from the moisture removal device A shown in FIG. 1, and the description of the same configuration will be omitted.

[0027] As shown in FIG. 3(C), in the moisture removal device A of Example 2, a float 12 (an example of "distance holding means") is provided below the waveguide 3. The float 12 is made of a heat-resistant material and has a buoyancy that allows it to float on the liquid surface of the liquid W while supporting the waveguide 3. Further, the float 12 has a size such that the distance h between the liquid surface of the liquid W and the emission part 3A becomes a predetermined distance when the float 12 floats on the liquid W. On the other hand, the waveguide 3 of Example 2 is configured to be able to move up and down. As a result, as the moisture of the liquid W evaporates and the liquid surface of the liquid W drops with respect to the container 2 (the weight of the liquid W decreases), the float 12 and the waveguide 3 also drop, so that the distance h is maintained at a predetermined distance.

[0028] [Example 3] The moisture removal device A in Example 3 will be described with reference to FIG. 4. FIG. 4(A) is a diagram showing the state before the irradiation of the microwave M (t = t0), and FIG. 4(B) is a diagram showing the state after a certain period of time has elapsed since the start of the irradiation of the microwave M (t = t1). Note that in Example 3, the description will focus on the differences from the moisture removal device A shown in FIG. 1, and the description of the same configuration will be omitted.

[0029] The water removal device A of Example 3 has a wire 13, a jack 14 (an example of "distance holding means"), and a mounting table 15 instead of the base 4. The wire 13 is attached to the mounting table 15 on which the container 2 is placed, and the jack 14 raises and lowers the mounting table 15 via the wire 13. That is, the jack 14 holds the distance h at a predetermined distance by pulling up the wire 13 to raise the container 2 in response to the evaporation of the moisture in the liquid W and the lowering of the surface (liquid level) of the liquid W with respect to the container 2 (the decrease in the weight of the liquid W).

[0030] In FIG. 4, the jack 14 is arranged above the container 2, and the container 2 and the liquid W are pulled up via the wire 13 to hold the distance h at a predetermined distance. Instead of this, a hydraulic jack (not shown) (an example of "distance holding means") that pushes up a weight placed on the upper part may be arranged below the container 2 (for example, the mounting table 15), and the container 2 and the liquid W may be pushed up by the hydraulic jack to hold the distance h at a predetermined distance.

[0031] [Example 4] The water removal device A in Example 4 will be described with reference to FIG. 5. Note that the description will focus on the points different from the water removal device A shown in FIG. 1, and the description of the same configuration will be omitted.

[0032] In Example 4, the container 2 forms a communication pipe together with a second container 16 (an example of "second container") arranged outside the storage 1. That is, the bottom of the container 2 and the bottom of the second container 16 are connected by a pipe 17. Thereby, the height of the liquid level in the container 2 and the height of the liquid level in the second container 16 become the same height. Further, the water removal device A has a supply unit 18 (an example of "distance holding means") that supplies the liquid W to the second container 16. The supply unit 18 has, for example, a storage tank (not shown) that stores the liquid W, and controls the opening and closing of the stopper of the storage tank in response to the evaporation of the moisture in the liquid W in the container 2 and the lowering of the liquid level of the liquid W with respect to the container 2 (the decrease in the weight of the liquid W), and supplies the liquid W to the second container 16. Thereby, the height of the liquid level in the container 2 rises and the distance h is held at a predetermined distance.

[0033] Next, the moisture removal method of this embodiment will be described with reference to FIG. 6.

[0034] First, solid block ice is put into the container 2 (step S1).

[0035] Next, the block ice in the container 2 is heated and thawed (step S2). As a result, the block ice in the container 2 melts into the liquid W.

[0036] Next, the container 2 containing the liquid W is stored in the storage 1 (step S3).

[0037] Next, the liquid W in the container 2 is irradiated with microwaves M (step S4). As a result, the moisture in the liquid W evaporates. Note that the irradiation with the microwaves M continues until the process shown in the flowchart ends.

[0038] Next, it is determined whether or not the moisture in the liquid W in the container 2 has sufficiently evaporated (step S5). For example, it is determined whether or not the weight of the liquid W has sufficiently decreased (to a predetermined weight) from the weight in the initial state before the irradiation with the microwaves M.

[0039] If it is determined that the moisture in the liquid W in the container 2 has sufficiently evaporated (step S5: YES), the process shown in the flowchart ends. On the other hand, if it is determined that the moisture in the liquid W in the container 2 has not sufficiently evaporated (step S5: NO), the distance h between the emission unit 3A and the liquid surface is adjusted so as to be maintained at a predetermined distance (step S6). For example, it may be adjusted by the distance holding mechanism of the moisture removal device A described in Examples 1-4, or the container 2 may be lifted manually and the base 4 may be replaced with a base 4 having a greater height for adjustment. After finishing step S6, the process proceeds to step S5. As a result, since the liquid W is continuously irradiated with the microwaves M and the distance h is maintained at a predetermined distance even when the moisture evaporates, the moisture in the liquid W can be efficiently removed.

[0040] Next, the experimental results of examining the change in the weight of the liquid W when the liquid W obtained by thawing block ice is irradiated with the microwave M will be described with reference to FIGS. 7(A) and 7(B). According to these experimental results, when 10 kg of the liquid W was placed in a plastic bucket and irradiated with the microwave M, about 5.6 kg of moisture was removed in 60 minutes. On the other hand, when 20 kg of the liquid W was placed in a hollow container and irradiated with the microwave M, about 19.3 kg of moisture was removed in 225 minutes.

[0041] As described above, the moisture removal device A of the present embodiment includes a waveguide 3 (an example of "irradiation means") that irradiates the liquid W containing moisture in the container 2 with the microwave M, the surface of the liquid W in the container 2, and a distance holding mechanism (an example of "distance holding means") that holds the distance h between the liquid W and the emission part 3A that emits the microwave M in the waveguide 3 at a predetermined distance.

[0042] Therefore, according to the moisture removal device A of the present embodiment, when evaporating the moisture of the liquid W by irradiating the microwave M, the microwave M can be continuously irradiated while maintaining the distance h between the emission part 3A of the microwave M and the liquid surface of the liquid W at a predetermined distance, and by setting the predetermined distance to an optimal distance for evaporating the moisture, the moisture of the liquid can be efficiently removed.

[0043] Further, the moisture removal method of the present embodiment includes a step S4 of irradiating the liquid W containing moisture in the container 2 with the microwave M (an example of "irradiation step"), and a step S6 of holding the distance h between the surface of the liquid W in the container 2 and the emission part 3A that emits the microwave M in the step S4 at a predetermined distance (an example of "distance holding step").

[0044] Therefore, according to the moisture removal method of the present embodiment, when evaporating the moisture of the liquid W by irradiating the microwave M, the microwave M can be continuously irradiated while maintaining the distance h between the emission part 3A of the microwave M and the liquid surface of the liquid W at a predetermined distance, and by setting the predetermined distance to an optimal distance for evaporating the moisture, the moisture of the liquid can be efficiently removed.

[0045] In step S2 of FIG. 6, it is also possible to heat and thaw block ice (an example of a "solid") to obtain liquid W. Note that the heating and thawing of the block ice may be performed in a container separate from container 2, and the resulting liquid W in the separate container may be transferred to container 2 and container 2 may be stored in storage 1.

[0046] Further, a heating mechanism (an example of a "heating means") for heating and thawing block ice (an example of a "solid") to obtain liquid W may be provided in the moisture removal device A. That is, the heating mechanism recovers the heat of the water vapor discharged from the exhaust port 6 by the exhaust fan (an example of a "discharging means") to heat the block ice. As a method of heating the block ice, for example, water vapor with heat may be directly blown onto the block ice, or a thawing chamber (not shown) for thawing the block ice may be prepared, the block ice may be stored in the thawing chamber, and the block ice may be heated by heating the inside of the thawing chamber with water vapor with heat.

[0047] [Modification Example] A modification example of the above-described Examples 1 to 4 will be described. The modification examples described below may be appropriately combined.

[0048] [Modification Example 1] In Modification Example 1, a liquid level gauge is provided in the moisture removal device A to measure the height of the liquid level of the liquid W in container 2 and measure the liquid level. For example, in the moisture removal device A of Example 4, a float-type liquid level gauge or the like is provided in the second container 16 to measure the liquid level. In the moisture removal device A of Examples 1 to 3, a weighing scale for measuring the weight of container 2 is provided, and the liquid level is measured based on the change in weight.

[0049] [Modification Example 2] In Modification 2, the liquid W before irradiation with the microwave M, which was thawed in step S2 of FIG. 6, is preheated. Specifically, a preheater for preheating the liquid W that was thawed in step S2 of FIG. 6 is provided in the moisture removal device A. For example, in Example 4, an IH (Induction Heating) device (an example of "preheating means") for heating the liquid W in the second container 16, or a preheater (an example of "preheating means") that recovers and heats the heat of the water vapor discharged from the exhaust port 6 is provided, and the initial temperature of the liquid W is raised by the preheater. In this way, by raising the temperature of the liquid W, the moisture in the liquid W can be efficiently evaporated by irradiation with the microwave M. Note that a heater for heating the liquid W during irradiation with the microwave M may be provided in the moisture removal device A and the liquid W may be heated.

Explanation of Signs

[0050] 1: Storage 2: Container 3: Waveguide 3A: Emission part 4: Base 5: Air supply port 6: Exhaust port 11: Spring base 11A: Spring 11B: Mounting plate 12: Float 13: Wire 14: Jack 15: Mounting table 16: Second container 17: Pipe 18: Supply part A: Moisture removal device S: Water vapor W: Liquid h: Distance

Claims

1. Irradiation means for irradiating microwaves onto a liquid containing moisture contained in a container, Distance holding means for holding the distance between the surface of the liquid contained in the container and the emission part that emits the microwaves in the irradiation means at a predetermined distance, A moisture removal device, characterized by comprising these.

2. A moisture removal device according to Claim 1, A storage for storing the container, Discharge means for discharging water vapor in the storage from the storage, A moisture removal device, characterized by comprising these.

3. A moisture removal device according to Claim 1 or 2, The distance holding means is a spring that supports the container, a moisture removal device characterized by this.

4. A moisture removal device according to Claim 1 or 2, The distance holding means is a float provided on the emission part and floating on the liquid, The float has a size such that when floating on the liquid, the distance between the surface of the liquid and the emission part becomes the predetermined distance, a moisture removal device characterized by this.

5. A moisture removal device according to Claim 1 or 2, The container forms a communication pipe together with another second container, The distance holding means supplies the liquid to the second container according to the amount of the liquid in the container reduced by evaporation of the liquid, a moisture removal device characterized by this.

6. A moisture removal device according to Claim 1 or 2, The distance holding means is a jack, The jack lifts the container according to the amount of the liquid in the container reduced by evaporation of the liquid, a moisture removal device characterized by this.

7. The moisture removal device according to claim 2, wherein: it is provided with heating means for heating the solid to thaw it into the liquid; the heating means is characterized in that it heats by using the heat of the water vapor discharged by the discharging means. The moisture removal device.

8. The moisture removal device according to claim 1 or 2, wherein: the moisture removal device further comprises preliminary heating means for heating the liquid before the irradiation means irradiates the microwave.

9. an irradiation step of irradiating a microwave to a liquid containing moisture in a container; a distance holding step of holding the distance between the surface of the liquid in the container and the emitting portion that emits the microwave in the irradiation step at a predetermined distance; A moisture removal method characterized by including:

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