JP3041070U - Cleaning structure for alkali metal contaminants - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To eliminate the incidental equipment and the operation of the equipment, to reduce the cost required, to reduce the complexity, and to further enhance the safety, and to wash the alkali metal contaminants. And SOLUTION: A sand layer that covers at least the surface of an alkali metal existing inside is provided, and a means for introducing outside air in a humid state and an exhaust system are provided inside, and the above-mentioned outside air is introduced. It is assumed that the means is air supply by a blower, and an auxiliary means for injecting a small amount of water is provided.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 Prior to disassembling and disposing of tanks, containers, and equipment that are in a contaminated state where alkali metals, especially sodium are attached and remained inside, the present invention is designed to prevent adverse environmental effects. The present invention relates to an improvement of a cleaning structure for making the material into a solid state.

[0002]

[Prior art]

 Conventionally, cleaning of containers and equipment contaminated by the above-mentioned alkali metals prior to disassembly and disposal is performed by using steam as shown in FIG. 2 or by alcohol as shown in FIG. Has become.

Alkali metals have a high chemical activity, react with a cleaning agent such as water or alcohol, and release hydrogen gas to be chemically inactivated. That is, in the case of sodium, it reacts with water to become sodium hydroxide, which reacts with alcohol to ethoxylate. In this case, if the tank, container, or equipment to be treated is filled with air, there is a risk that the released hydrogen gas reacts with oxygen in the air to cause an explosion. .

Here, the cleaning structure using water vapor shown in FIG. 2 will be described. In FIG. 2, reference numeral 1 is a container in which sodium N remains attached. Reference numeral 2 denotes a gas tank for an inert gas such as nitrogen gas. By constantly feeding the inert gas from the gas tank 2 into the container 1, the inside of the container 1 is replaced and the hydrogen gas concentration is lowered. Furthermore, 3 is a steam generator, which injects steam into the container 1 whose inside is filled with an inert gas and filled. By injecting this steam, sodium N is converted into sodium hydroxide N ', so that the sodium N is inactivated. Reference numeral 4 is an exhaust tank, and 5 is an exhaust system with a flame arrester (flashback prevention device) 6 interposed in the middle.

Further, FIG. 3 shows a cleaning structure using alcohol, and portions common to FIG. 2 are denoted by the same reference numerals and detailed description thereof will be omitted. In this case, the inside of the container 1 is replaced with an inert gas such as nitrogen gas from the gas tank 2 and filled, and then the alcohol 7a is injected into the container 1 by the pump 8 from the alcohol tank 7. The alcohol 7a is circulated by the circulation pump 9.

After the alkali metal (sodium N) is inactivated by the above-described structure and the generation of hydrogen gas is stopped, the container 1 is disassembled by mechanical means such as a gas cutting method and disposed of. It was supposed to do.

[0007]

[Problems to be solved by the device]

 However, according to the conventional cleaning structure described above, many additional devices such as a continuous injection device for an inert gas such as nitrogen gas and an injection device for a cleaning agent such as steam or alcohol are required, and the operation is complicated. Therefore, the cost required for equipment and operation will increase. In addition, hydrogen gas was generated and suppressed along with the deactivation of the alkali metal, and the possibility of an explosion due to the hydrogen gas was left to some extent.

[0008]

[Purpose of the invention]

 Therefore, the present invention has been made by paying attention to the actual situation and problems of the related art, and by solving the problems, the incidental equipment and the operation of the equipment are eliminated to reduce the cost required. It is an object of the present invention to provide a cleaning structure for an alkali metal pollutant, which is not complicated and which can obtain further safety.

[0009]

[Means for Solving the Problems]

 In order to achieve this object, the cleaning structure for an alkali metal pollutant according to the present invention is provided with a sand layer covering at least the surface of the alkali metal present inside, and means for introducing outside air in a humid state, An exhaust system is provided, the above-mentioned means for introducing the outside air is an air supply by a blower, and a means for injecting a small amount of water is additionally provided.

[0010]

[Action]

 With this configuration, the continuous injection device for the inert gas such as nitrogen gas and the injection device for the cleaning agent such as water vapor and alcohol, which were required in the past, are no longer required, which results in a large cost in terms of equipment and work. Savings can be achieved, and by providing a sand layer, more reliable safety can be obtained as described below.

That is, by providing a sand layer to cover the surface of the alkali metal, it is possible to cause an unpredictable excess due to the expected inflow of accumulated water or a small amount of injected water in the container to be cleaned, the internal part of the equipment. Even if a large amount of hydrogen is generated at one time due to the reaction, the hydrogen gas and the alkali metal that is at a high temperature due to the reaction with water are separated, and the alkali metal becomes the ignition source. And prevent explosion.

Further, even if the hydrogen gas contained in the sand layer comes into contact with the high temperature alkali metal and starts an explosion on the surface, the explosion flame passes through the sand layer and is cooled and extinguished. Therefore, the flame does not reach the hydrogen gas that exists in a large amount outside the sand layer, and it will be extinguished by only a small explosion in the sand layer.

Further, even if a large amount of water passes through the sand layer, the flow area of the outflow side of the water increases due to the water retaining and spreading effects of the sand. The peaks are flattened out. Therefore, it is possible to prevent the passing water from concentrating at one time and reacting with the alkali metal, and it is possible to suppress the generation of a large amount of hydrogen gas and the temperature increase of the alkali metal which becomes an ignition source.

[0014]

[Embodiment of the invention]

 Next, a preferred embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a cleaning structure for an alkali metal contaminant according to the present invention.

In FIG. 1, reference numeral 10 indicates a container in which sodium N remains attached. A sand layer 11 covering the sodium N is provided on the surface of the sodium N. Specifically, the sand layer 11 has a plurality of through holes in the lower body of the container 10, and the dry sand is supplied from the through holes. It is formed by charging. Further, in this embodiment, the container 10 has a cylindrical structure having a complicated structure (not shown) having a diameter of 3 m and a height of 8 m, and sodium N is partially converted to sodium hydroxide. The sand layer 11 had a pressure of about 30 cm.

Reference numeral 12 in the drawing denotes a blower, and this blower 12 is connected to the horizontal pipe of the container 10 to send a large amount of outside air containing moisture into the container 10. The air blown by the blower 12 is specifically 50 m ³ / min, the atmospheric temperature is 30 degrees Celsius, and the humidity is 80%, and 1.169 Kg of water is poured every minute, and it operates for 5 hours a day. Then, in 4 days, 1403 kg of water will be poured into the container 10.

Further, in the figure, 13 indicated by an imaginary line is a water injection device for a small amount of water, and this water injection device 13 is used as an auxiliary device when the atmosphere is dry and the humidity is low such as in winter. The pump 14 performs the water injection work. Although reference numeral 15 in the figure shows an exhaust system, it goes without saying that the safety can be further strengthened by interposing a flame arrester (not shown). Then, in order to monitor the reaction status in the container 10, the hydrogen concentration in the container 10 is constantly measured by a measuring device.

The cleaning structure for alkali metal contaminants according to the present embodiment is configured as described above. Here, the practical operation and action of this cleaning structure will be explained. Immediately after the blower 12 is operated to start feeding the outside air into the container 10, the reaction product (a small amount Sodium) begins to deliquesce, and the deliquescent liquid and reaction products flow down the inner wall surface of the container 10 and reach the surface of the sand layer 11, the deliquescent liquid is absorbed in the sand layer 11, and the reaction products are on the surface of the sand layer 11. The process will be further deliquesced, and this process will be extremely gentle.

Further, sodium N on the lower end plate of the container 10 covered with the sand layer 11 is inactivated by reacting with the deliquescent liquid flowing down in the sand layer 11 and the moisture diffusing from the surface air of the sand layer 11. I will go. In this reaction process, a reaction sometimes occurs in the sand layer 11 with a dull explosion sound, and the temperature of sodium N on the lower end plate rises due to the reaction.

If the hydrogen concentration in the container 10 reaches a remarkable value, the blower 12 stops air supply to avoid explosion, and argon gas is injected and exhausted to calm the reaction. The air supply by the blower 12 is restarted when the hydrogen concentration decreases.

When the working time in one day ends, air supply is stopped and argon gas is injected into the container 10 to replace the inside of the container 10, and the air supply port and the exhaust port are closed with, for example, a blind plate, Cut off outside air. By repeating this operation for one week in the case of the scale of the embodiment, the hydrogen concentration does not increase even when air is supplied, and the operation of disassembling the container 10 can be started.

[0022]

[Effect of the invention]

 The alkali metal contaminant cleaning structure according to the present invention is constructed and operates as described above. As a result, the sand layer will ensure even greater safety, the equipment and the cost of operating the equipment will be significantly reduced, and the cleaning operation itself will be simple and easy.

[Brief description of the drawings]

FIG. 1 is a view showing a cleaning structure embodying the present invention.

FIG. 2 is a diagram showing a conventional example, showing a cleaning structure with water vapor.

FIG. 3 is a diagram showing a conventional example and a cleaning structure using alcohol.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Container 11 Sand layer 12 Blower 13 A small amount of water injection device 14 Pump 15 Exhaust system N sodium

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Shozo Fujioka 6 Toko Kikai Kogyo Co., Ltd. 263 Muramatsu, Tokai-mura, Naka-gun, Ibaraki Prefecture

Claims (3)

[Utility model registration claims] 1. Alkali metal contamination, characterized in that a sand layer covering at least the surface of an alkali metal present inside is provided, and means for introducing outside air in a moisture-containing state and an exhaust system are provided inside. Body wash structure. 2. The cleaning structure for alkali metal contaminants according to claim 1, wherein the means for introducing the outside air is air blown by a blower. 3. The cleaning structure for alkali metal contaminants according to claim 1 or 2, further comprising auxiliary means for injecting a small amount of water.