JP2023045441A - Tritium water collection system - Google Patents

Abstract

To provide a simple and safe device for collecting and removing liquid-state tritium water from polluted water containing the tritium water.SOLUTION: In a tritium water collection system including a tritium water collector where tritium water is cooled, solidified and collected from polluted water containing the tritium water,: a cooling medium for cooling is a coolant for automobile consisting of 42-47 wt.% water, 47-51 wt.% ethylene glycol, 1.5-2.0 wt.% diethylene glycol and 3.5-4.5 wt.% various kinds of additives; a compound which is a phosphoric acid organic compound and where the mass of phosphoric acid in the compound is one-tenth or less is contained by 1.4-2.6 wt.% to the total amount of the various kinds of additives; and the coolant for automobile is not diluted and solid-formulated.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an apparatus for collecting tritium, and more particularly to an apparatus for collecting tritiated water present in wastewater (contaminated water) contaminated with radioactive substances resulting from an accident at a nuclear power plant by coagulation.

The water used to cool the nuclear power plant that caused the accident (contaminated water) contains various radioactive substances. are required to do so.

Here, radioactive substances other than radioactive tritium (tritium) in the contaminated water can be removed by an already practical multi-nuclide removal system (ALPS) or the like. However, tritium cannot be easily removed because its physical properties are very similar to those of hydrogen.

In general, tritium binds to oxygen and often exists as tritiated water in the form of gas or liquid in polluted water.

As a device for removing tritium, Patent Document 1 discloses a technical idea of separating tritium from tritium vapor using a palladium hydrogen permeable membrane or the like.

Further, Patent Document 2 discloses a technical idea of separating tritium by causing gas containing tritiated water to flow through zeolite as an adsorbent.

JP-A-7-253487 JP-A-10-128072

However, in the devices described in Patent Documents 1 and 2, both of which are designed to process gases containing tritium water vapor or tritium water, there is a risk of diffusion of radioactive substances. It is difficult to provide a simple and highly safe device because it needs to be handled in a high gaseous state.

On the other hand, tritiated water has different physical properties in that its freezing temperature is different from that of ordinary water, i.e., light water. is.

Accordingly, an object of the present invention is to provide a simple and safe apparatus for collecting and removing liquid tritiated water.

In order to solve the above problems, the present invention is a tritiated water collector for collecting tritiated water in contaminated water,
- a box-like container that can be substantially sealed;
- an inlet provided in the container for injecting contaminated water;
- an outlet provided in the vessel for discharging the treated water; and - an adsorbent placed inside the vessel in the passageway of the contaminated water to adsorb the tritiated water, cooled to a temperature below the freezing point of the tritiated water. The contaminated water is injected from the inlet, and when the contaminated water passes through the adsorbent, the tritiated water solidifies, the solidified tritiated water is adsorbed by the adsorbent, and the remaining contaminated water is discharged from the outlet. characterized by

According to this, the solidified tritiated water can be sorted out from normal water, adsorbed and collected, and efficient contaminated water treatment becomes possible.

Furthermore, the tritiated water collector of the present invention may be characterized by being portable and sealable. By doing so, the collected tritiated water can be safely stored at a predetermined storage location.

Furthermore, the tritiated water collector of the present invention may be characterized in that the adsorbent contains porous earth. Here, the porous earth has a large number of various types of spaces of different sizes, and activated clay is suitable, but is not limited thereto. According to this, the tritiated water in the contaminated water is efficiently collected by this space in a solidified state.

Further, the present invention is a tritiated water collection system for collecting tritiated water from contaminated water containing tritiated water for solving the above problems,
- a tritiated water collector as previously described,
- piping supplying chilled contaminated water to the tritiated water collector;
- piping for delivering contaminated water discharged from the tritiated water collector;
- a peripheral cooling device for cooling the periphery of the tritiated water collector to a temperature below the freezing point of the tritiated water;

According to this, it is possible to provide a system capable of collecting tritiated water efficiently and safely.

Furthermore, in the tritiated water collection system of the present invention, the peripheral cooling device is
It may be characterized by having - a cooling tank in a substantially closed state, - a refrigerant circulation pipe laid in the cooling tank and circulating a refrigerant for cooling the contaminated water, and - a stirrer installed in the cooling tank. . According to this, the periphery of the tritiated water collector is appropriately cooled, and tritiated water can be efficiently collected.

Furthermore, the tritiated water collection system of the present invention may be characterized in that the refrigerant of the peripheral cooling device is a propylene glycol aqueous solution. By doing so, it is possible to precisely control the cooling temperature.

Furthermore, the tritiated water collection system of the present invention is
- It may be characterized by having a precision cooling device for precisely cooling the contaminated water injected into the tritiated water collector to a temperature near the freezing point of the tritiated water. According to this, since the temperature of the contaminated water injected into the tritiated water collector is controlled within an appropriate range, tritiated water can be efficiently collected.

Furthermore, in the tritium water collection system of the present invention, the precision cooling device is
- a cooling tank in a substantially closed state; - a contaminated water inlet for injecting contaminated water into the cooling tank; - a contaminated water outlet for discharging contaminated water from the cooling tank; and a stirrer installed in the cooling tank. According to this, a precision cooling device can be easily realized.

Furthermore, the tritiated water collection system of the present invention may be characterized in that the refrigerant for precision cooling is a propylene glycol aqueous solution. By doing so, it is possible to precisely control the cooling temperature.

Furthermore, the tritiated water collection system of the present invention is
- It may be characterized by having a pre-cooling device for pre-cooling the contaminated water injected into said precision cooling device. In this way, since the contaminated water is cooled to near the predetermined temperature before precision cooling, precision cooling can be performed in a short time and with high accuracy.

Furthermore, in the tritium water collection system of the present invention, the preliminary cooling device is
- a cooling tank in a substantially closed state; - a contaminated water inlet for injecting contaminated water into the cooling tank; - a contaminated water outlet for discharging contaminated water from the cooling tank; and a stirrer installed in the cooling tank. According to this, the preliminary cooling device can be easily realized.

Furthermore, the tritiated water collection system of the present invention may be characterized in that the refrigerant used for pre-cooling is an ethylene glycol aqueous solution. When the requirement for temperature maintenance is not strict, the use of ethylene glycol, which is easy to handle and inexpensive, can be expected to be economically effective.

Furthermore, the tritiated water collector or the tritiated water collection system of the present invention provides a coagulation promotion in the flow path of the contaminated water inside the precision cooling device, the peripheral cooling device, the tritiated water collector, or the piping connecting them. It may be characterized by providing a coagulation accelerator charging part for charging the agent.

For example, if a coagulation accelerator such as sodium borate is added to the polluted water, the coagulation is promoted and tritiated water can be collected efficiently.

According to the tritiated water collector and the tritiated water collection system of the present invention, tritiated water is solidified by temperature control by precision cooling, and is collected (captured and collected) by being adsorbed on porous earth, and Since the collector can be detached and stored in an airtight manner, safe and efficient tritiated water collection treatment can be performed while minimizing the danger of tritium diffusion.

1 is an explanatory diagram of a tritiated water collection system according to one embodiment of the present invention; FIG. 1 is a perspective view of a cooling device of a tritiated water collection system according to one embodiment of the present invention; FIG. 1 is a perspective view of the periphery of a tritiated water collector according to one embodiment of the present invention; FIG. 1 is a perspective view of a tritiated water collector of one embodiment of the present invention; FIG. 1 is a cross-sectional view of a tritiated water collector of one embodiment of the present invention; FIG. 1 is a side view of a tritiated water collector of one embodiment of the present invention; FIG.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram of a tritiated water collection system 1 according to one embodiment of the present invention.

The tritiated water collection system 1 includes, in order of the flow of the contaminated water, a contaminant removal unit 10 for removing contaminants mixed in the contaminated water, a pre-cooling device 20 for pre-cooling the contaminated water, a pre-cooled contaminant A precision cooling device 30 that precisely cools water, a tritiated water collector 40 that collects tritiated water from the precisely cooled contaminated water, a peripheral cooling device 50 that cools the periphery of the tritiated water collector 40, and tritiated water is removed. It has a water tank 60 for storing contaminated water.

Furthermore, a tertiary refrigerant tank 70 for cooling the refrigerant used in the precision cooling device 30 and the peripheral cooling device 50, a secondary refrigerant tank 80 for cooling the refrigerant used in the tertiary refrigerant tank 70 and the pre-cooling device 20, and a secondary refrigerant tank 80 includes a primary refrigerant cooling device 90 for cooling the .

The contaminant removal unit 10 has a mesh filter inside to prevent contaminants contained in contaminated water from being sent downstream.

FIG. 2 is a perspective view showing the structure of the precooling device 20 used in the tritiated water collection system 1 of one embodiment of the present invention. It is a rectangular parallelepiped that has a space inside in a substantially closed state (a state in which there are no openings except for the inlet and outlet for refrigerant, contaminated water, etc.). Refrigerant pipes 23 (four sets) that spiral downward and rise linearly near the bottom, contaminated water inlets 24 that are provided on the upper surface of the rectangular parallelepiped and supply contaminated water to the inside of the rectangular parallelepiped, and contaminated water. Contaminated water outlet 25 for sending out contaminated water supplied from the inlet, and two agitators with four blades installed on the shaft to agitate the contaminated water inside the rectangular parallelepiped and agitate by rotating the shaft. a vessel 26;

The cooling pipe 23 is preferably coil-shaped, has a height of 50 cm, an outer diameter of 6 cm, and has a spiral shape of 6 to 7 stages.

In addition to the preliminary cooling device 20, the precision cooling device 30, the tertiary refrigerant tank 70, and the secondary refrigerant tank 80 can also have the same structure. Here, in the precision cooling device 30, the refrigerant inlet 31, the refrigerant outlet 32, the refrigerant pipe 33, the contaminated water inlet 34, the contaminated water outlet 35, and the stirrer 36 are replaced.

In the refrigerant tank, the object to be cooled is not the contaminated water but the refrigerant to be cooled. Refrigerant inlet 71, refrigerant outlet 72, refrigerant pipe 73, refrigerant inlet 74 to be cooled, refrigerant outlet 75 to be cooled, stirrer 76. In secondary refrigerant tank 80, refrigerant inlet 81, refrigerant outlet 82, refrigerant pipe 83, a coolant inlet 84 to be cooled, a coolant outlet 85 to be cooled, and a stirrer 86.

The configurations of the above-described cooling device and cooling tank, and the peripheral cooling device to be described later may not be the same, and each may be configured by a well-known cooling mechanism suitable for the application.

FIG. 3 is a perspective view of the periphery of the tritiated water collector 40 of one embodiment of the present invention. Four tritiated water collectors 40 are installed in the peripheral cooling device 50 . The peripheral cooling device 50 has a structure similar to that of other cooling devices, and has a refrigerant inlet 51, a refrigerant outlet 52, a refrigerant pipe 53, and a stirrer 56. However, what is cooled is the tritiated water collector 40 installed inside and the surrounding piping and air.

A plurality of tritium water collectors 40 are installed so that operation does not have to be stopped during replacement when one of them becomes full, but the number is limited to four. 1 or more.

The external dimensions of the peripheral cooling device 50 with four built-in tritium water collectors 40 are preferably about 200 cm in width, 140 cm in height, and 60 cm in depth. Therefore, it is not limited to this dimension. Furthermore, on both sides in the height direction, for example, four sets of grooves with guides having lengths of 20 cm and 16 cm are provided, and the tritiated water collectors 40 are held in these grooves.

FIG. 4 is a perspective view, FIG. 4 is a sectional view, and FIG. 5 is a side view of a tritiated water collector 40 according to one embodiment of the present invention. The tritiated water collector 40 consists of a rectangular parallelepiped container 41 having a space inside a substantially closed state, a contaminated water inlet 42 provided on the upper surface of the container 41 as an inlet for contaminated water, and an outlet for treated water (treated water). and a treated water outlet 43. The outer dimensions of the container are preferably 100 cm or more in width, about 50 cm in height, and about 5 to 10 cm in depth, but are not limited to these dimensions in view of the scale of the entire system. Although the upper lid and bottom plate of the container have a detachable structure, they may have a different structure.

A pipe 421 extends horizontally upward inside the container 41 from the contaminated water inlet 42 , and a plurality of ejection ports 422 capable of ejecting contaminated water downward are provided in the container 41 .

Inside the container 41, three layers of tritiated water collection layers 411a, 411b, and 411c are provided in the height direction. Each layer has a metal grid-like net 412 on the bottom, and a fine net-like container 413 made of metal or polypropylene is placed thereon. . As the adsorbent 414, porous earth having a large number of spaces of different sizes, such as activated clay, is desirable. The filling amount may be appropriately changed in consideration of the concentration of contaminated water, the concentration of tritiated water to be collected, and the like.

A bottom plate 415 having a large number of holes 416 is provided below the tritiated water trapping layer 411c, which is the lowest layer, and a treated water receiving pan is provided below the bottom plate 415 for receiving treated water and flowing it toward the treated water outlet 43 with an inclination. 431, and the end of the receiver 431 is connected to a pipe 432 directed to the treated water outlet.

If necessary, a well-known valve may be provided in the vicinity of the contaminated water inlet 42 or the treated water outlet 43 to adjust the flow rate or prevent backflow.

The tritiated water collector 40 is configured to be detachable from the peripheral cooling device 50 while maintaining a substantially sealed state. For example, well-known means such as providing the vessel 41 of the tritiated water collector 40 with a shape or member that slides with a groove with a guide provided on the peripheral cooling device 50 side may be used. Also, the closed state can be maintained by automatically or manually closing the aforementioned valve. In addition, the tritiated water collector 40 should be detachable by remote control. In this way, the risk of radiation exposure can be reduced.

The operation of the tritiated water collection system 1 having such a configuration will be described.
First, in the primary refrigerant cooling device 90, Freon gas, which is the primary refrigerant, is cooled. Although the details of the primary refrigerant cooling device 90 are not shown, a known freon gas cooling device using a compressor and a condenser may be used. Freon gas, as is well known, has a high cooling capacity, but its temperature stability is not sufficient and it is not suitable for precision cooling. Here, Freon gas is roughly cooled to 0 degrees Celsius or less.

Next, the cooled Freon gas is sent to the refrigerant inlet 81 of the secondary cooling tank 80, passes through the refrigerant pipe 83, flows to the refrigerant outlet 82, and finally returns to the primary cooling tank 90. . Here, the secondary refrigerant tank 80 is filled with the refrigerant to be cooled that flows from the refrigerant inlet 81 to be cooled and flows to the refrigerant outlet 82 to be cooled. Here, as the refrigerant to be cooled, a 50% aqueous solution of ethylene glycol (referred to as EG brine), which has slightly higher temperature stability than freon gas, is used.

Additives such as antirust additives and surface tension reducing surfactants may be added to the EG brine. As the additive, those containing a part or all of synthetic fatty acid, molybdenum soda, tolyltriazole, caustic soda aqueous solution and caustic potash aqueous solution for further alkalinization, which are highly effective, are desirable.

Refrigerant pipe 83 of secondary cooling tank 80 and stirrer 86 act to exchange heat between Freon gas and EG brine, and EG brine is preferably -0.5 degrees Celsius to 3.0 degrees Celsius, or more. Preferably, the cooling is performed by selecting a temperature within the range of 1.0°C to 2.5°C at which the contaminated water can be pre-cooled and the tertiary refrigerant can be appropriately cooled.

These temperatures are controlled by controlling the flow rate of Freon gas and EG brine using valves and flow meters (not shown) and by controlling the stirring of EG brine by operating/stopping the stirrer 86 and adjusting the stirring speed. It can be realized.

This cooled EG brine is sent to the tertiary cooling bath 70 . In the tertiary cooling tank 70 , while proceeding to the refrigerant inlet 71 , refrigerant pipe 73 and refrigerant outlet 72 , another refrigerant to be cooled in the tertiary cooling tank is cooled with the help of the stirrer 76 . The refrigerant to be cooled used here is preferably a 30% aqueous solution of propylene glycol (called PG brine). PG brine is suitable for precision cooling because it can have a high water content, which makes it more temperature-stable than EG brine, taking advantage of the greater latent heat of water, and , EG brine has a lower oxidizing effect on metals, so that less antirust additives can be used.

Additives such as antirust additives and surface tension-lowering surfactants may be added to the PG brine. As the additive, those containing a part or all of synthetic fatty acid, molybdenum soda, tolyltriazole, caustic soda aqueous solution and caustic potash aqueous solution for further alkalinization, which are highly effective, are desirable.

Here, the PG brine is preferably in the range of 0.5 degrees Celsius to 4.0 degrees Celsius, more preferably 2.0 degrees Celsius to 3.5 degrees Celsius, so that tritium water collection is most efficient. The temperature is selected and cooled so as to maintain the temperature variation preferably within +-0.2 degrees, more preferably within +-0.1 degrees.

These temperatures are controlled by controlling the flow rate of EG brine and PG brine using valves and flow meters (not shown), and by controlling the operation/stopping and stirring speed of the stirrer 76 to control the stirring of the PG brine. It can be realized by doing.

Next, treatment of contaminated water will be described. Contaminated water supplied to this system from a source of contaminated water containing tritiated water (not shown) first passes through the contaminant removal unit 10 to remove contaminants (garbage, solid matter, etc.) mixed in the contaminated water. Remove by filter. Note that this part is not necessary if those things have already been removed.

Dirty water is then supplied to the inside of the device from the contaminated water inlet 24 of the precooling device 20 . On the other hand, the refrigerant inlet 21 of the precooling device 20 is piped so as to be supplied with the EG brine from the secondary cooling tank 80 described above. With the aid of the agitator 26, the contaminated water is heat-exchanged with the EG brine to a temperature similar to or slightly higher than the freezing temperature of the tritiated water, preferably 4.5°C to 6.0°C. It is cooled by selecting a temperature of 0° C., more preferably in the range of 4.5° C. to 5.0° C. at which precise cooling can be performed efficiently, and flows out from the contaminated water outlet 25 to the next process. Here, the solidification temperature of tritiated water is 4.49 degrees Celsius at 1 atmosphere, but it may fluctuate in a high-pressure or low-pressure environment.

These temperatures are controlled by controlling the flow rate of EG brine and contaminated water using valves and flow meters (not shown) and by controlling the stirring of contaminated water by operating/stopping the stirrer 26 and adjusting the stirring speed. It can be realized by doing.

Subsequently, the pre-cooled contaminated water is supplied from the contaminated water inlet 34 of the precision cooling device 30 to the interior of the device. On the other hand, the refrigerant inlet 31 of the precision cooling device 30 is piped so as to be supplied with the PG brine from the tertiary cooling tank 70 described above, and while proceeding to the refrigerant pipe 33 and the refrigerant outlet 32, With the aid of the stirrer 36, the contaminated water is heat exchanged with the PG brine to a temperature near the freezing temperature of tritiated water, i. Preferably, a temperature in the range of 3.5 degrees Celsius to 4.5 degrees Celsius is selected at which the collection of tritiated water is most efficient, and the temperature fluctuation is preferably within +-0.2 degrees. , more preferably within +-0.1 degrees, and flows out from the contaminated water outlet 35 to the next process.

These temperatures are controlled by controlling the flow rate of the PG brine and contaminated water using valves and flow meters (not shown), and by controlling the operation/stopping of the stirrer 36 and adjusting the stirring speed to control the stirring of the contaminated water. It can be realized by doing.

Subsequently, the precisely cooled contaminated water is directed to one of four contaminated water inlets 42 of tritiated water collectors 40 . PG brine from the tertiary refrigerant tank 70 is supplied to the refrigerant inlet 51 of the peripheral cooling device 50 incorporating the tritiated water collector 40, and is stirred while traveling to the refrigerant pipe 53 and the refrigerant outlet 52. With the help of the vessel 56, the tritiated water collector 40 installed inside and the piping around it and the air exchange heat with the PG brine, preferably at 1.5 degrees Celsius or higher. Below the solidification temperature, more preferably in the range of 3.0 degrees Celsius to 4.4 degrees Celsius, the temperature at which tritiated water is most efficiently collected is selected, and the temperature fluctuation is preferably +- It is cooled to maintain within 0.2 degrees, more preferably within +-0.1 degrees.

These temperatures are controlled by controlling the flow rate of the PG brine using valves and flow meters (not shown), and by controlling the operation/stopping of the stirrer 56 and adjusting the stirring speed to control the air around the tritiated water collector 40. It can be realized by controlling the stirring of

Inside the tritiated water collector 40, the supplied contaminated water is sprayed from the contaminated water inlet 42, through the pipe 421 and the ejection port 422, to the uppermost tritiated water collection layer 411a. Here, the tritiated water is preferably kept at an appropriate temperature of 1.5 degrees Celsius or more and less than the tritium water solidification temperature, more preferably in the range of 3.0 degrees Celsius to 4.4 degrees Celsius, and already Partially solidifying or still in a liquid state (supercooled state), it tries to pass through the adsorbent 414 in the net-like container 413 of the tritiated water-collecting layer 411a. At that time, the solidified tritiated water is adsorbed by the adsorbent 414 by the stimulation caused by the contact with the adsorbent 414 , which causes the solidified tritium water to rapidly solidify.

Here, there are two additional tritiated water-collecting layers, and solidified tritiated water is adsorbed also in the middle layer 411b and the bottom layer 411c.

In addition, tritiated water and normal water have a freezing point difference of about 4.5 degrees Celsius, and the dissociation degree of tritiated water is small, so the energy required for solidification is small. It is believed that even when mixed with normal water, most of it is solidified and captured between 1.5 degrees Celsius and the tritium water solidification temperature.

Contaminated water from which tritiated water has been removed in this way (referred to as treated water) is sent from the treated water receiver 432 to the treated water outlet 43 via the pipe 432 .

After that, the treated water is stored in a water storage tank 60, and after component measurement, etc., if it is suitable for drainage, it is discharged directly or via a storage tank 65 into a river or the sea or released into the atmosphere by evaporation. or stored in storage tank 65 until final disposal. Moreover, when residual tritiated water still exists, it may be supplied from the water storage tank 60 to the pre-cooling device 20 and the tritiated water may be collected again.

In addition, in order to accelerate the solidification of tritiated water, a coagulation accelerator input portion may be provided in the piping portion immediately before supplying the contaminated water to the tritiated water collector 40 . For example, a configuration is adopted in which a coagulation accelerator such as fine powder of sodium borate is injected into the pipe using a cylinder. The fine powder of sodium borate has the effect of promoting the solidification of tritiated water when the temperature is below the freezing point. In this case, it is desirable that the sodium borate has as little water of crystallization as possible, but it does not necessarily have to be crystalless. The coagulation accelerator is not limited to sodium borate, and may be sodium silicate, sodium nitrate, sodium hypophosphite, or the like, as long as it has an effect of accelerating coagulation. Also, the place where the coagulation accelerator is introduced is not immediately before supplying the contaminated water to the tritium water collector 40, but inside the precision cooling device 30, between there and the tritium water collector 40, or at the tritium water collector. 40 may be injected inside.

In addition, although not mentioned in the explanation so far, the pipes for transporting the refrigerant and contaminated water are also cooled using appropriate brine so that the temperature does not rise.

In the description so far, the concentration of the brine is 50% aqueous solution of ethylene glycol in the case of EG brine, but it is not limited to this, preferably 30% to 55%, more preferably 40% to 40%. An appropriate concentration of 55% may be used. In the case of the PG brine, a 30% aqueous solution of propylene glycol was used, but the concentration is not limited to this, preferably 10% to 50%, more preferably 20% to 40%. Also, the combination of ethylene glycol and propylene glycol is not a limitation, and other refrigerants may be used as long as they can be used separately for pre-cooling and precision cooling.

In addition, although freon is used for cooling the EG brine, the present invention is not limited to this, and refrigerants such as non-freon refrigerants (eg, propane, butane, and isobutane) and ammonia may be used.

Furthermore, in the explanation so far, the preliminary cooling device 20 using EG brine and the precision cooling device 30 using PG brine are provided as means for cooling contaminated water, but only one of them can be used to cool the water with the required temperature accuracy. is possible, the other can be omitted. In that case, either the secondary cooling bath 80 or the tertiary cooling bath 70 may be unnecessary.

In addition, although activated clay is mentioned as a suitable example of the porous earth, it is not limited to this, and may be kaolin, acid clay, diatomaceous earth, zeolite, china clay, or ceramics.

Incidentally, the piping between the devices constituting the system of the present invention may be appropriately provided with flow control valves, check valves (check valves), cocks, drains, and the like.

Next, another embodiment of the present invention will be described.
In this embodiment, coolant used for automobiles is used as cooling water. This embodiment uses the automotive coolant described in Japanese Patent Application Laid-Open No. 2019-026797 by the same inventor as the present application.

The technical field of automotive coolant applied this time generally relates to coolant for cooling automobile engines, the base material of the coolant, and the additive of the coolant, especially the coolant excellent in rust prevention and the coolant base material, and coolant additives thereof.

As a background technology, people of the earth must seriously tackle the global environmental protection now that drastic changes in the global environment are becoming a serious problem. However, maintaining the living environment as much as possible should also be explored. Under these circumstances, fuel cell vehicles are the ultimate ideal for automobiles, but for the time being, in addition to hybrid vehicles, there is a continuing demand for performance improvements in vehicles using conventional engines.

Such improvements in engine performance always lead directly to an increase in the burden on the cooling system. Therefore, it is desired to improve the performance of the coolant used in the cooling system.

As such a coolant, Patent Document 1 discloses a technical idea of a coolant containing a water-soluble organic medium as a main component and containing an aliphatic polycarboxylic acid containing 4 or more carboxylic acid groups and/or a salt thereof. ing. According to this, it is possible to provide a radiator coolant having a long replacement life for aluminum alloy radiators.

As a prior art document, there is JP-A-2003-342559.

However, the coolant of Patent Literature 1 has a problem that it is difficult to satisfy various requirements for the coolant.

In other words, as the function of the cooling system is enhanced, the need to uniformly cool all parts of the cooling system increases. In addition, the higher the performance and the lighter the engine, the more severe the high-frequency vibration of each part of the engine.

The components used in engine cooling systems are iron and its alloys, copper, brass, aluminum, aluminum alloys, synthetic rubber, and various plastics, and static electricity is generated due to high-frequency vibration generated by engine vibration. . The generated static electricity has a different potential depending on each part.

That is, the occurrence of a potential difference in the cooling system immediately leads to the occurrence of galvanic corrosion, which is a severe condition for rust prevention. In particular, with iron, when high-frequency vibration increases, sufficient attention must be paid to anti-corrosion measures.

Therefore, the coolant applied this time (this invention) (hereinafter, the part "this invention" may be read as "the coolant applied this time") has excellent cooling performance, improves rust prevention performance for metal, An object of the present invention is to provide a long-life automotive coolant.

As a means for solving the problems, the first invention is a base material for automotive coolant for solving the above problems, wherein water is less than 50%, and the balance is ethylene glycol and diethylene glycol. It is characterized by a ratio between 15:1 and 53:1.

Here, it is the ratio before adding the additive, which is different from the ratio in the automotive coolant after adding the additive.

According to this, the anti-freezing effect of the glycols can be fully exhibited, and furthermore, by suppressing the water ratio, evaporation of water alone can be suppressed, and oxidation of the metal can be prevented.

A second aspect of the present invention is an additive for automobile coolants for solving the above problems, characterized by containing a monovalent carboxylic acid and a divalent carboxylic acid.

Although it is desirable to add this to the coolant base material of the first invention, it is not limited to this, and may be added to a commonly used coolant base material. This also applies to the following additives.

The ratio of monovalent carboxylic acid to divalent carboxylic acid is preferably about 1:1, but is not limited thereto.

According to this, these carboxylic acids are generally used for preventing corrosion of metals, and by adding them to coolant, a rust-preventing effect can be obtained.

A third aspect of the present invention is a coolant additive for automobiles for solving the above-mentioned problems, characterized by containing sodium molybdate.

According to this, by adding an appropriate amount of sodium molybdate to a place where metals are used in combination, abnormal metal corrosion can be almost completely eliminated.

The fourth aspect of the present invention is a coolant additive for automobiles for solving the above-mentioned problems, characterized in that it contains a fluorosurfactant.

According to this, the high-molecular-weight fluorine-based surfactant has a large effect of significantly lowering the surface tension at the interface between the liquid and the solid. A high-performance engine is like a nest of high-frequency vibrations, and countless vacuums are generated on the cooling surface. As a method of avoiding the damage caused by this phenomenon to the utmost limit, the surface tension of the liquid is lowered by a fluorine-based polymeric surfactant, thereby greatly suppressing the chances of the metal being oxidized.

The fifth aspect of the present invention is an additive for automobile coolants for solving the above-mentioned problems, characterized in that it contains a phosphoric acid organic polymer compound.

According to this, by adding a phosphoric acid organic polymer compound such as an organic phosphate ester with a low phosphoric acid content, the iron reacted with the phosphoric acid is attached to the phosphoric acid organic polymer compound side. Therefore, no iron phosphate (electrical non-conductor) is generated on the metal surface side. This has the effect of preventing metal corrosion by preventing potential difference from occurring.

The sixth aspect of the present invention is a coolant additive for automobiles for solving the above problems, characterized in that it contains an antifoaming agent.

In particular, it is desirable to have an effect of eliminating bubbles generated at 80° C. or higher.

The seventh aspect of the present invention is a coolant for automobiles for solving the above problems, wherein at least one of the second to sixth aspects of the present invention is added to the base material for coolant of the first aspect. It is characterized by adding an agent.

According to this, the effects of the coolant base material and the coolant additive described above can be exhibited together.

The eighth aspect of the present invention is the coolant for automobiles according to the seventh aspect of the present invention for solving the above-mentioned problems, characterized in that it is a fixed prescription that is not diluted.

Conventional antifreeze standards stipulate the properties of the undiluted liquid and stipulate that the undiluted liquid should be diluted with water in actual use. However, the required properties for the coolant (cooling liquid) became stricter, and a coolant containing fixed water was desirable, so a fixed formulation that was not diluted was adopted.

However, as long as the dilution is properly managed, it may be a stock solution that is finally diluted to achieve this ratio.

The ninth aspect of the present invention is the automotive coolant testing apparatus of the seventh or eighth aspect of the present invention for solving the above problems, comprising a transparent pipe between the flow meter and the heating tank. characterized by

By doing so, the size of the bubbles can be visually confirmed when testing the coolant for automobiles, which facilitates the evaluation of the coolant.

As an effect of the invention, according to the automotive coolant base material, the automotive coolant additive, or the automotive coolant of the present invention, the cooling performance is excellent, the rust prevention performance for metals is improved, and the long-life automotive coolant is provided. can provide.

The most preferred formulation of the automotive coolant of the present invention is as follows.

As an automotive coolant condition, the weight percent is
Reference Optimal range Preferred range Water 45 42-47 40-49
Ethylene glycol 49 47-51 45-53
Diethylene glycol 2 1.5-2.5 1- 3
Various additives 4 3.5-4.5 3- 5
In this state, the base composition of the coolant base without additives is 46.9% water and 24.5:1 ethylene glycol:diethylene glycol.

Next, the ratio of various additives is assuming that the total of additives is 100,
Criterion Optimal range Preferred range Monohydric synthetic carboxylic acid 27 22-32 18-36
Divalent synthetic carboxylic acid 27 22-32 18-36
Caustic soda 20 16-24 12-28
Rust inhibitor for copper 10 6-14 2-18
Mixed antioxidant 10 6-14 2-18
Sodium molybdate 2 1.4-2.6 1.0-3.0
Phosphoric acid organic polymer compound 2 1.4-2.6 1.0-3.0
Fluorinated surfactant 1 0.6-1.4 0.2-1.6
Defoamer 1 0.6-1.4 0.2-1.6
is desirable.

Here, the antifreeze standards specify the properties of the undiluted solution and, in actual use, stipulate that it should be diluted with water to an antifreeze concentration of 30% to 55%. The demanding properties of the coolant have become more demanding due to the demanding engine operating requirements, increasing the need for coolants containing stationary water.

In other words, the anti-freezing effect of recent coolants, especially suitable for diesel engines, is only a part of the expected effect of the coolant. must be protected, and performance must be maintained to maximize cooling effectiveness.

Therefore, fixed ratio coolants containing undiluted water have become desirable. Here, the water content of 47.4% (that is, less than 50%) is because it is known that the addition of water significantly lowers the freezing point (freezing point) of ethylene glycol, and it is effective as an antifreeze solution. In addition, by suppressing the ratio of water, the opportunity for only water to evaporate and become steam is suppressed. This greatly reduces the chances of the metal surface oxidizing. In particular, in order to suppress the evaporation of water alone, it is desirable that the ratio of water clearly falls below 50%.

Diethylene glycol can improve the solubility of water in ethylene glycol by adding a small amount. As a result, the freezing point of the coolant can be lowered.

Next, a specific manufacturing process will be described.
Step A: A monohydric synthetic carboxylic acid is dissolved in a small amount of ethylene glycol.
Step B: Sodium molybdate is dissolved in a small amount of water until clear. Step C: Antifoaming agent is dissolved in a small amount of butyl triglycol ether.
Step D: A phosphoric acid organic polymer compound is dissolved in ethylene glycol or water.
Step E: A fluorosurfactant is dissolved in ethylene glycol or water.
Step F: Dissolve mixed antioxidant with ethylene glycol or water.
Step G: Add caustic soda to the rest of the water, and after a predetermined time has passed, add an antirust agent for copper.
Step H: Add the products of Steps A to F to the product of Step G.
Step I: Add a dihydric synthetic carboxylic acid and diethylene glycol to the remaining ethylene glycol.
Step J: The product of Step H is mixed into the product of Step I in portions.

In a "glycol-rich" state in which the ratio of glycols (ethylene glycol + diethylene glycol) is higher than water, and by mixing in such a process, water is incorporated into the glycols, which is what is called water-in-oil. state can be achieved.

Next, the characteristics and effects of each additive will be described.
The monohydric synthetic carboxylic acid is preferably isonanoic acid (C ₉ H ₁₈ O ₂ ) (trade name Kyowanoic-N), but is not limited to this. In addition, the divalent synthetic carboxylic acid is
_{dodecanedioic acid C12H22O4 or} HOOC( _CH2 ) _10COOH or sebacic acid _C10H18O4 or _HOOC ( _CH2 ) _8COOH
So, it is preferable to use dodecanedioic acid and sebacic acid in almost equal amounts, so that the side effects disappear. This is because sebacic acid has isomers and may work differently, so it may not be possible to achieve the desired purpose with sebacic acid alone. not something to do.

Synthetic carboxylic acid is generally widely used as a general anti-rust agent for metals, and anti-rust effect can be obtained by adding it to the coolant base material. However, considering the usage conditions of the engine coolant, it may cause metal corrosion, and especially when it reacts with copper ions, the frequency is high, so it is desirable not to use more than a certain amount. The combination of monovalent and divalent synthetic carboxylic acids in equal amounts was adopted from the analysis of experimental results.

Regarding rust inhibitors for copper, benzotriazole and tolyltriazole are widely used as rust inhibitors for copper. In contrast, an event in which aggression occurs violently is confirmed.

In that case, instrumental analysis may show a reaction indicating the presence of alkanolamine, and such a phenomenon is less likely to occur when tolyltriazole alone is used. Based on the above results, only tolyltriazole was adopted as a rust inhibitor for copper.

For the mixed antioxidant, butylated hydroxytoluene (BHT) is preferred, but not limited thereto. As for operating conditions of the engine coolant, the temperature of the inner surface of the cooling system is extremely high, and the flow velocity of the coolant is high.

Antioxidants are of the self-sacrificing type, and the higher the temperature, the greater the concern about side effects. Since the temperature of the liquid is 105° C. or less even in the currently mainstream pressurized type, BHT (butylated hydroxytoluene) is mainly considered.

It should be noted that if the antioxidant is added more than necessary, there is a great concern that it will decompose more than necessary and cause harm to the main body. Therefore, since the antioxidant cannot be added in a certain amount or more at one time, it is necessary to periodically add the antioxidant.

When sodium molybdate is added in the above-described amount to a place where metals are used in combination, abnormal metal corrosion is almost completely eliminated.

Here, when sodium molybdate is used in an appropriate amount, it has the effect of protecting the surface of iron and aluminum. , difficult to use, but can be easily used as a fixed formulation type that does not require dilution.

It is pointed out that sodium molybdate may pollute the environment, but if it is a long-life coolant, it will not pose an environmental problem if care is taken when disposing of it.

Regarding caustic soda, inorganic alkalis generally include caustic soda and caustic potash, and caustic soda is used. As for caustic potash, in practical experiments, abnormal values are observed in many cases, and the cause analysis cannot be specified in many cases. On the other hand, it is generally said that caustic potash has a lower surface tension than caustic soda when it contains less water, but in the case of this coolant, since there is sufficient water, caustic soda does not pose a problem.

The purpose of adding caustic soda is to neutralize most of the additives mentioned so far, which are weakly acidic.

Surflon (registered trademark, AGC Seimi Chemical Co., Ltd.) is suitable for the fluorosurfactant, but it is not limited thereto. Fluorinated surfactants have a great effect of significantly lowering the surface tension at the interface between liquid and solid.

High-performance engines in recent years are in a state like a nest of high-frequency vibrations, and countless vacuums are generated on the cooling surface. As a method to avoid the damage caused by this phenomenon to the utmost limit, the surface tension of the liquid is lowered by a fluorine-based polymer surfactant, the concentration of water contained in the coolant base material is suppressed to less than 50%, and additives are added to the liquid. By selecting only substances that have a high affinity for water, the opportunity for only water to evaporate and become water vapor is minimized. This countermeasure greatly suppresses the chance of the metal being oxidized.

As for the phosphoric acid organic polymer compound, organic phosphoric acid esters such as ChelexTD (triisodecylphosphite) and ChelexOL (trioleylphosphite) manufactured by SC Organic Chemical Co., Ltd. are suitable, but are limited to these. not a thing The mass of phosphoric acid in the phosphoric acid organic polymer compound is preferably reduced to 1/10 or less, more preferably 1/20 or less.

Here, conventionally, iron rust prevention in coolant was handled by forming a thin and uniform coating of iron phosphate on the surface of iron metal, but it is extremely difficult to form an extremely thin and uniform coating of iron phosphate. It was difficult and often caused potential differences.

In the present invention, by using a phosphoric acid organic polymer compound containing a small amount of phosphoric acid, the iron reacted with phosphoric acid is bound to the phosphoric acid organic polymer compound side instead of the metal surface side. .

In practical experiments, there was no trace of iron phosphate on the metal surface, and very little precipitation was observed on the liquid side, but this had no effect on the performance of the coolant.

The antifoaming agent is desirably capable of eliminating foam generated at 80° C. or higher, and Pluronic L-61 (trade name) is suitable, but is not limited to this.

Although not included in the composition described above, a small amount of sodium nitrate may be added as an additive. Addition of sodium nitrate is effective in stably protecting aluminum and aluminum alloys.

There are various ways to prevent aluminum from rusting, but whether it is alumite processing or nitriding, the potential difference between the film forming material and aluminum is greatly different. The method of adding a small amount of sodium nitrate is the most reliable in practical experiments.

In the present invention, a method of forming a rust preventive coating on the metal inside the cooling system is not adopted as a method of extending the service life, but a method of avoiding contact with oxygen by making the coolant adhere to the interface as much as possible is premised. devised a prescription for

However, the reality is that it is impossible to reduce the contact of oxygen to 0, and for iron, on the premise of the generation of a very small amount of iron ions, a small amount of phosphoric acid is bound to the polymer. A method of adding a molecular organic phosphate compound (surfactant) and collecting it on the coolant side was adopted.

When formulating formulations from this point of view, there are additives that must be added periodically (for example, every 3 years or every 5 years) during use. Antioxidants are self-sacrificing agents, and the amount that can be added at one time is small. preferable.

Carboxylic acid is considered to be able to endure basically for about 10 years at the amount prescribed at the beginning.

Copper rust inhibitors (tolyltriazole, etc.) are also highly consumable additives due to their tendency to form complexes with other copper substances. Therefore, it is an additive that needs to be added periodically.

Sodium molybdate and polymeric organic phosphorus compounds (surfactants) do not need to be replenished for 4 to 5 years, but if they are to be used for a longer period of time, the method of adding them after measuring the remaining amount is recommended. preferable.

<Experimental results>
Fluorine-based surfactants are prescribed because it is inevitable that the inner surface of the engine cooling contains a small amount of air, so by minimizing the air particles, the air directly contacts the cooling surface. things can be avoided. This can enhance the cooling effect

More specifically, when a liquid becomes a gas, it takes away latent heat. The gas in the liquid forms bubbles, and the smaller the bubbles, the more quickly they will collapse, so they will absorb a lot of heat. It is preferable to add a fluorine-based surfactant in order to make many small bubbles generated in the cooling liquid.

Furthermore, the structure of the current radiator is pressurized around 1.5 atmospheres, and the pressure is adjusted with a valve at the reserve tank. The temperature of the combustion chamber of the engine is high, and gas is generated in the cooling liquid in contact with the combustion chamber of the engine due to the heat of the engine. As described above, it is preferable that the size of the bubbles generated in the cooling liquid is small, so it is preferable to add a fluorine-based surfactant.

In fact, it was decided to verify the effect of the coolant of the present invention by modifying the circulatory corrosion test equipment in the current antifreeze standard (JIS K2234).

Although illustration is omitted, it is the coolant testing apparatus 1 of the present invention, which is an improved version of the apparatus shown in the above JIS.

Although the details of this test apparatus 1 are based on JIS, coolant circulates from a heating tank 11 incorporating an assembly test piece (not shown) through a radiator 12, a water pump 13, and a flow meter 14. Here, the flow rate A tempered glass pipe 15 . and/or installing pipes 16 made of heat-resistant glass. Furthermore, these pipes are made transparent so that the inside can be observed. Note that the transparent member is not limited to glass.

When the test liquid (equivalent to coolant) was flowed under various conditions in such a device and observed while changing the temperature and flow rate, it was found that the liquid formulated with a fluorosurfactant had smaller bubble diameters, resulting in The color becomes darker and the temperature of the thermometer attached to the tester becomes lower. In this test, bubbles are always observed in the liquid when the liquid is circulated.

As a specific test method, the motor 17 that circulates the test liquid is equipped with a transmission (not shown), and after operating at 500 rpm for 55 minutes each hour during the test time of 8 hours a day, It is preferable to operate the transmission for 5 minutes to 1,000 rpm, then return to 500 rpm after 5 minutes, and repeat this for 8 hours. It should be noted that it is possible that the operating conditions will be changed in the future.

The reason why I focused on fluorine-based surfactants was that when other surfactants were prescribed, the results varied greatly when repeated tests were performed, and I felt there was a problem with heat resistance. This is because it is more than 10 times higher than when a surfactant is used, and a new phenomenon considered to be a side effect may occur.

Furthermore, in the metal corrosion test, it is considered that the effect on the test piece is more realistic than the standard test (continuous heating test), in which the test is repeated 90 to 120 days after heating for 8 hours and leaving for 16 hours.

Current internal combustion engines are like nests of static electricity, and creating an anti-rust coating on the inner surface of the engine can easily cause galvanic corrosion, like creating a department store with a potential difference on the inner surface of the engine.

For iron, as a measure to prevent contact with air (oxygen), it is covered with a carboxylate, and in the event that iron ions are generated, a polymer surfactant containing phosphoric acid is formulated for the purpose of catching iron ions on the liquid side. .

As a method for evaluating the coolant (cooling liquid) prescribed according to this, various ideas were conceived, and as a result of trying laboratory methods, the following conclusions were obtained.

1) In the test methods of public standards such as JIS, the continuous heating method and continuous air blowing method are adopted as methods for accelerating the results. A 30% diluted solution is to be used.

This time, it was a test of a liquid that was used as it was without dilution, and the current radiator structure is that all radiators are pressurized and air is blocked, so air blowing decided to delete.

As a test method, the JIS standard adopts a method of continuous heating, but in actual use, it is impossible to repeat heating for 8 hours and leaving for 16 hours. Long life coolant) is 720 hours, but this time, we conducted a test with a test period of 2 months, 3 months, 4 months, and 5 months, and compared it with the test method of the JIS method. .

As a result, it was determined that there was no significant difference in the results after 3 months. However, although it is not possible to prove whether this test method covers all formulations, stable results were obtained with formulations similar to this formulation.

2) We believe that this formula has an advantage over conventional formulas, as a rust prevention method for iron, and as a characteristic of current engines, it is also a nest of high-frequency vibrations that are very prone to static electricity. Since it has properties that can be said, there is no problem in creating a film to prevent rust if the electrochemical potential difference is the same as that of the base metal, but in reality it is impossible.

In particular, if iron does not satisfy the conditions, it becomes a nest of galvanic corrosion, resulting in great damage, and there is a problem that the engine cannot be repaired, so caution is required.

In the examples described so far, the blending ratio of the coolant base material and the coolant additive is a reference, but the ratio is not limited to this ratio. As long as it is within a suitable range, a certain effect can be obtained.

In addition, the types of additives may be decreased or increased, and in that case, of course, the compounding ratio may vary.

1 Tritium water collection system 20 Pre-cooling device 30 Precise cooling device 40 Tritium water collector 50 Peripheral cooling device 60 Storage tank 70 Tertiary refrigerant tank 80 Secondary refrigerant tank 90 Primary refrigerant cooling device

Claims (1)

A tritiated water collection system for collecting tritiated water from contaminated water containing tritiated water,
a) A container in a substantially closed state that has no openings except for the inlet and outlet for refrigerant and contaminated water, an inlet provided in the container for injecting the contaminated water, and an inlet provided in the container for discharging treated water. and an adsorbent containing porous earth containing any one or more of activated clay and kaolin, which is placed in the passage of the contaminated water inside the container and adsorbs the tritiated water. and the contaminated water cooled to a temperature below the freezing point of the tritiated water is injected from the inlet, and when the contaminated water passes through the adsorbent, the tritiated water solidifies, and the solidified a tritiated water collector characterized in that tritiated water is adsorbed by the adsorbent and residual contaminated water is discharged from the outlet;
b) piping for supplying cooled contaminated water to the tritiated water collector;
c) piping for delivering contaminated water discharged from the tritiated water collector;
d) a precision cooling device that precisely cools the contaminated water injected into the tritiated water collector to a temperature near the freezing point of the tritiated water using a specific refrigerant ;
e) a pre-cooling device for pre-cooling the contaminated water to be injected into the precision cooling device with a specific refrigerant ,
For automobiles, wherein the specific refrigerant comprises 42-47% by weight of water, 47-51% by weight of ethylene glycol, 1.5-2.0% by weight of diethylene glycol, and 3.5-4.5% by weight of various additives. A coolant containing 1.4 to 2.6% by weight of a phosphoric acid organic compound in which the mass of phosphoric acid in the compound is 1/10 or less of the total amount of the various additives. A tritiated water collection system, characterized in that it is an automotive coolant that is a fixed formula without dilution.

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