JPS6127720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a treatment device for treating waste liquid containing radioactive substances, such as a liquid scintillator used in radioisotope laboratories, laboratories, hospitals, etc.

Conventionally, liquid scintillators used in radioisotope research laboratories, laboratories, hospitals, etc. dissolve luminescent substances such as terphemyl in a solvent such as toluene, benzene, or xylene, and increase the luminescence intensity or change the emission spectrum. A small amount of activator is added to change the radioactivity, and the measurement sample is mainly mixed into a liquid scintillator and its radioactivity is measured. Because it contains radioactive materials such as ^3H and ^14C , it was stored in designated tanks and left in the open. In addition, waste liquid containing other radioactive substances may be incinerated in electric furnaces or firebrick furnaces, but these furnaces not only require large equipment, but also completely remove the waste liquid. It has many drawbacks, such as being unable to combust, producing harmful soot, and damaging the inside of the furnace.

The present invention was invented in view of the above, and provides an apparatus that can completely vaporize and burn waste liquid containing radioactive substances, which is the liquid to be treated, and that can be made smaller than the conventional incinerator. The purpose is to provide.

In order to achieve the above object, the present invention provides a vaporizing section that is disposed in the upper part of a furnace body and that vaporizes a liquid to be treated after mixing it with air, a combustion chamber that burns vaporized gas from the vaporizing section, and a combustion chamber that combusts vaporized gas from the vaporizing section. a catalytic combustion section located in the passageway of the combustion gas to be discharged and configured to completely burn incompletely burned components in the combustion gas; An inner plate that is connected to the vaporization combustion section and forms a passage inside thereof through which combustion gas from the vaporization combustion section passes, and an outer plate that surrounds the outer periphery of the inner plate and communicates with the combustion chamber. a heat exchange section equipped with an air introduction passage; and a liquefaction section provided with a cooling mechanism disposed at the lower part of the furnace body and connected to the heat exchange section to cool and liquefy the combustion gas from the heat exchange section. In the apparatus for treating waste liquid containing a radioactive substance, the vaporization section includes a vaporization member made of a heat-resistant porous material with an auxiliary heater attached to the outer peripheral part, and a vaporization member disposed inside the vaporization member, An arbitrary number of through holes are bored on the circumferential surface, and inside the holes, a feed tube for the liquid to be treated is provided for feeding the liquid to be treated, and air is sent to generate bubbles in the liquid to be treated. It is constructed by arranging the respective open ends of the supply pipes for the

Next, embodiments of the present invention will be described in detail based on the accompanying drawings.

Figure 1 is a vertical sectional front view of the entire device, Figure 2 is
FIG. 3 is a cross-sectional plan view of the vaporization combustion section, and FIG. 3 is an enlarged longitudinal sectional view of the vaporization combustion section.

The apparatus according to the present invention is located at the upper part of a stainless steel furnace body 2 provided in a vertically long box-shaped casing 1, and includes a vaporizing section that vaporizes a waste liquid containing radioactive substances, which is a liquid to be treated; a combustion chamber 8 in which the vaporized gas is combusted; a catalyst body 23 made of platinum located below the combustion chamber 8 and provided to completely burn incompletely combusted substances contained in the combustion gas after the combustion; and a vaporizing combustion section 3 located at the center of the furnace body 2, through which high-temperature combustion gas from the vaporizing combustion section 3 passes,
The vaporization combustion section 3 passes combustion air around its outer periphery.
a heat exchange section 4 that can heat the combustion air introduced into the furnace; a liquefaction section 5 that is located at the lower part of the furnace body 2 and that cools and liquefies the combustion gas that has passed through the heat exchange section 4; It consists of:

The configuration of each of the above parts will be explained in detail below.

The vaporization part of the vaporization combustion part 3 includes a cylindrical part 7 whose upper part is sealed by a sealing flange 13 and whose lower part is open, and a ceramic cylinder housed inside the cylindrical part 7.
A vaporizing member 10 made of a heat-resistant porous material such as fiber, an auxiliary heater H2 attached to the outer periphery of the cylindrical portion 7, and an arbitrary number of heaters embedded approximately in the center of the vaporizing member 10 on its circumferential surface. A mixing cylinder 11 having through-holes 12 . A supply pipe 21 for supplying air to make the waste liquid in 11 into bubbles is fixed to the lower end of a connecting rod 14 located below the vaporizing member 10 and fixed to the bottom plate of the mixing cylinder 11, and connected to the vaporizing member 11. It consists of a receiving tray 15 having an outer diameter approximately equal to the outer diameter of 10. Note that the receiving tray 15 is for taking out the vaporizing member 10, and is used together with the airtight flange 13 to hold the mixing cylinder 1.
1, the vaporizing member 10 is caught on the tray 15 and pulled upward.

The combustion chamber 8 of the vaporization combustion section 3 is located below the cylindrical section 7 of the vaporization section and is connected to the cylindrical section 7 to adjust the amount of combustion air supplied, which will be described later. A combustion air inlet equipped with a damper 9 and a combustion starting heater H2 arranged below the receiving tray 15 are provided.

Further, the area where the vaporization combustion section 3 of the furnace body 2 is arranged is filled with a heat insulating material 6 surrounding the entire peripheral side of the vaporization combustion section 3 and a heat insulating material 17 surrounding the upper part of the vaporization combustion section 3.

The feed pipe 20 has its open end located approximately at the center of the mixing cylinder 11, while the other end extends from inside the mixing cylinder 11 to the outside of the furnace body 2, and is disposed along the inner wall of the casing 1. 1 through a pump P3 for delivering the liquid to be treated, which is provided at a predetermined portion of the inner wall of the
It is connected to a liquid to be treated tank 19 housed inside the lower part of the casing 1 . In addition, the supply pipe 21 has its open end located below the open end of the feed pipe 20 in order to blow air into the liquid to be treated that is fed into the mixing cylinder 11 by the feed pipe 20 to form bubbles. It is located at the lower part of a certain mixing cylinder 11, while the other end extends from inside the mixing cylinder 11 to the outside of the furnace body 2, and is arranged along the inner wall of the casing 1. Connected to supply pump P1.

Reference numeral 16 in FIGS. 1 and 2 is an upper lid of the furnace body 2, and the upper lid 16 and the space between the airtight flange 13 are fixed with screws 18, 18 through the heat insulating material 17.

The heat exchange section 4 includes an inner plate 22 which is connected to the lower end of the vaporization combustion section 3 and is provided to form an internal passage through which the combustion gas from the catalyst body 23 of the vaporization combustion section 3 passes while descending. and an outer plate 2 which is the central part of the furnace body 2 and surrounds the outer periphery of the inner plate 22 with an appropriate space.
It consists of 4. The outer plate 24 has an inclined plate on its upper part to form a passage connecting the outer peripheral space of the inner plate 22, which is a combustion air introduction passage, with the combustion air introduction port of the combustion chamber 8. 25, and a notch-shaped step 26 is formed approximately in the center thereof and on one side below the air inlet of the combustion chamber 8. The inner plate 22 has a stepped portion 26.
A horizontal wall board 2 facing the outer board 24 facing the
7 is attached so as to form an appropriate space 28 between it and the outer panel 24. In addition, the heat exchange section 4 includes
An air intake port 29 located below the step portion 26 and between the inner plate 22 and the outer plate 24;
An air intake port 30 fitted with a filter is provided on the side wall of the casing 1 at a location close to 9, and air is drawn between the inner plate 22 and the outer plate 24 from the air intake port 29 through the air intake port 30. The combustion air thus generated rises while rotating along the outer circumference of the inner plate 22, passes through the cavity 28, further rises, and enters the combustion chamber 8 through the air inlet from the inclined plate 25. It is.

The liquefaction section 5 is provided with a circulation pipe 31 configured to surround the lower outer periphery of the furnace body 2 and connected to the inside of the inner plate 22 of the heat exchange section 4, and the circulation pipe 31 is provided with a circulation pipe 31 for circulating cooling water. While connected to a cooling water tank 32 disposed at the bottom of the casing 1, an inclined bottom plate 33 is provided at the bottom of the lower furnace body 2, and the inclined bottom plate 33
A drain pipe 36 of a recovery tank 35 equipped with a drain tank 34 is connected to the discharge port at the lower end. An opening 37 provided on the side surface of the lower furnace body 2 near the exhaust port of the slanted bottom plate 33 is connected to a vacuum type blower P2 disposed inside the casing 1 via an intake pipe 38, while an exhaust port of the blower P2 is It is connected to the lower end of an exhaust pipe 39 extending upward along the inner wall of the casing 1, and the upper end of the exhaust pipe 39 projects upwardly to the outside of the casing 1, and an adsorption filter 41 for adsorbing radioactive substances is installed therein. Connected to the duct 40.

Note that the symbols T1, T2, T3, shown in FIG.
T1 is a temperature sensor installed in each part of the furnace body 2, and is used to detect the temperature of each part of the furnace body 2 during operation, which will be described later. The vessel T2 includes the combustion chamber 8 and the catalyst body 23.
In between, temperature detectors T3 are attached between the vaporization combustion section 3 and the heat exchange section 4, respectively. Further, T4 is a cooling water temperature detector that detects the temperature of the circulation pipe 31 of the liquefaction section 5, and T5 is an exhaust gas temperature detector attached to the exhaust pipe 39.

Next, the operation and operation of the apparatus configured as described above will be explained.

In order to treat the liquid to be treated, for example, the waste liquid of a liquid scintillator, first, a pump P1 for supplying vaporizing air and a blower P connected to the opening 37 of the liquefaction section 5 are used.
2 is operated for a certain period of time, air is sent from the open end of the supply pipe 21 into the mixing cylinder 11 by the operation of the vaporizing air supply pump P1, and when this air passes through the vaporizing member 10, it remains in the vaporizing member 10. While the vaporized gas from the previous operation is sent to the combustion chamber 8, air from outside the casing 1 is sent from the air inlet to the combustion chamber 8 via the air intake port 30 and the air intake port 29 by the operation of the blower P2. The remaining gas enters the inside of the furnace body 2, mixes with the residual vaporized gas, and further descends inside the furnace body 2, and other residues present throughout the furnace body 2 also pass through the opening provided in the liquefaction section 5, which is the lower furnace body 2. 37, the air is discharged through an intake pipe 38, an exhaust pipe 39 of the blower P2, and a duct 40, and residual vaporized gas and the like are removed.

Next, stop blower P2, and start heater H.
2 to preheat the vaporizing member 10, and also to preheat the inside of the combustion chamber 8 and the catalyst body 23 by operating the starting heater H1.

When the temperature sensor T2 provided on the auxiliary heater H2 and the temperature sensor T3 provided below the catalyst body 23 detect and confirm the appropriate temperature for combustion in each part, that is, the vaporization member 10 and the combustion chamber 8.
When the catalyst body 23 satisfies the temperature conditions necessary for vaporizing or burning the liquid to be treated,
When the pump P3 for feeding the liquid to be treated is operated, the liquid to be treated drops into the mixing cylinder 11 from the liquid to be treated tank 19 through the introduction pipe 20. The dropped liquid to be treated becomes bubble-like due to the bubbling effect of the air from the supply pipe 21, becomes an air mixture gas through the through holes 12, and enters the vaporizing member 10 heated by the auxiliary heater H2. , is vaporized and becomes vaporized gas. The vaporized gas is heated and ejected into the combustion chamber 8, and combustion is started by the starting heater H1. When the combustion gas sucked into the blower P2 and descending passes through the catalyst body 23, its incompletely combusted components are almost completely combusted by reaction with the catalyst body 23. In addition, during this combustion
³ H and ¹⁴ C are processed into water and carbon dioxide, respectively.

Once combustion starts, when high-temperature combustion gas passes through the heat exchanger 4, the heat of the combustion gas is transferred to the combustion air via the inner plate 22, and even if the starting heater H1 is turned off, the combustion chamber remains The temperature is maintained at an appropriate level to maintain stable combustion conditions. In addition, in the combustion starting operation, as a preliminary step until the inside of the combustion chamber 8 and the catalyst body 23 are heated to an appropriate temperature and a stable combustion state is maintained, the blower P2 is operated according to the adjustment of the opening/closing degree of the damper 9. Combustion chamber 8
The heat generated by the starting heater H1 can be reduced by adjusting the ratio of the amount of air supplied to the starting heater H1 and the amount of heat generated by the starting heater H1, and by alternately operating the blower P2 and the starting heater H1 for an appropriate amount of time. The combustion chamber 8 and the catalyst body 2 while keeping the amount to a minimum
3. Perform temperature control. Then, when the temperature detectors T2 provided in various parts of the furnace body 2 display a predetermined temperature, the starting heater H1 is turned off. In other words, even if the starting heater H1 is turned off, the combustion chamber 8
The inside temperature is maintained at the appropriate temperature to maintain stable combustion conditions.

The temperature of the combustion gas descending within the furnace body 2 is lowered once in the heat exchange section 4, and when it further descends and enters the liquefaction section 5, it is further lowered to a lower temperature by the cooling water circulating within the circulation pipe 31. cooled down to Here, water, which is a combustion product of hydrogen containing ³ H, which has been reduced to below the regulation value by the combustion, is liquefied and stored in the recovery tank 35, and carbon containing ¹⁴ C is converted into carbon dioxide gas. Intake pipe 3 from opening 37 of the vaporizing section
Air is taken in to the duct 8 and exhausted to the duct 40 through the exhaust pipe 39.

When all the waste liquid in the liquid to be treated tank 19 has been burned, the auxiliary heater H2 and the pump P3 for feeding the liquid to be treated are stopped, and the temperature detector T1 and the temperature detector T are turned off.
The operation of the pump P1 and the blower P2 is continued for a predetermined period of time until the respective specified temperatures are detected and confirmed by the exhaust gas temperature detector T5 and the exhaust gas temperature detector T5, thereby exhausting the residual gas in the vaporizing member 10 and the furnace body 2. After exhausting the residual gas, the pump P1 is stopped, and then the temperature of the upper and lower portions of the catalyst body 23 is checked using the temperature detector T2 and the temperature sensor T3, and then the blower P2 is stopped.

As described above, the present invention is arranged in the upper part of the furnace body,
A vaporization section that mixes the liquid to be treated with air and then vaporizes it; a combustion chamber that burns the vaporized gas from the vaporization section; and a combustion chamber that burns the vaporized gas from the combustion chamber. a catalytic body for completely combusting incompletely burned components; and a catalytic combustion part located in the center of the furnace body and connected to the catalytic body of the evaporative combustion part, and formed by an inner plate. a heat exchange section that includes a passage through which combustion gas from the vaporization combustion section is passed, and an air introduction passage that communicates with the combustion chamber formed between the inner plate and an outer plate surrounding the outer periphery thereof; and a liquefaction section, which is disposed at the lower part of the furnace body and connected to a passage through which the combustion gas of the heat exchange section passes, and includes a cooling mechanism that cools and liquefies the combustion gas from the heat exchange section. In an apparatus for treating waste liquid containing radioactive substances, the vaporizing section in the vaporizing combustion section includes a vaporizing member formed of a heat-resistant porous material with an auxiliary heater attached to the outer periphery, and disposed inside the vaporizing member, It is equipped with a mixing cylinder having an arbitrary number of through holes bored in its circumferential surface, and inside the mixing cylinder there is a feed pipe for the liquid to be treated for feeding the liquid to be treated, and an air bubble in the liquid to be treated. Since the opening ends of the supply pipes for sending air are arranged in order to produce a can. Additionally, the overall structure can be made more compact than conventional large electric furnaces and firebrick furnaces, requiring less installation space and can be easily installed in radioisotope research laboratories, laboratories, hospitals, etc. This has the effect of allowing these facilities to safely and easily dispose of waste liquid containing radioactive materials themselves.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a section longitudinally, FIG. 2 is a cross-sectional plan view, and FIG. 3 is an enlarged vertical sectional view of the main part. DESCRIPTION OF SYMBOLS 1... Casing, 2... Furnace body, 3... Vaporization combustion section, 4... Heat exchange section, 5... Liquefaction section, 8... Combustion chamber, 9... Damper, 10... Vaporization member, 11
...Mixing tube, 12...Through hole, 15...Saucer, 1
9...Liquid tank to be treated, 20...Feed pipe, 21...
... Supply pipe, 23 ... Catalyst body, 29 ... Air intake port, 31 ... Circulation pipe, P1, P3 ... Pump, P2 ... Blower, T1, T2, T3, T
4, T5...temperature detector, H1...starting heater, H2...auxiliary heater.

Claims (1)

[Claims] 1. A vaporization section located in the upper part of the furnace body to vaporize the liquid to be treated after mixing it with air, a combustion chamber that combusts the vaporized gas from the vaporization section, and a passageway for the combustion gas discharged from the combustion chamber. a catalytic combustion section for completely combusting incompletely burned components in the combustion gas; The combustion chamber is provided with a passage through which combustion gas from the vaporization combustion section formed by the inner plate passes, and communicates with the combustion chamber formed between the inner plate and an outer plate surrounding the outer periphery thereof. A heat exchange section provided with an air introduction passage, and a cooling device disposed at the lower part of the furnace body and connected to a passage through which the combustion gas of the heat exchange section passes, cooling and liquefying the combustion gas from the heat exchange section. In an apparatus for treating waste liquid containing radioactive materials, the vaporization section in the vaporization combustion section includes a vaporization member formed of a heat-resistant porous material with an auxiliary heater attached to the outer circumference; a mixing cylinder disposed inside the vaporizing member and having an arbitrary number of through holes bored in the circumferential surface, and inside the mixing cylinder,
A feed tube for the liquid to be treated for feeding the liquid to be treated and a supply tube for feeding air to generate bubbles in the liquid to be treated are configured so that their open ends are respectively arranged. Equipment for treating waste liquid containing radioactive materials.