JPS604896A - Waste liquor concentrating solidifying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The coagulation-sedimentation method is a conventional treatment method for radioactive waste liquid.

There are ion exchange method and evaporation concentration method. The coagulation-precipitation method involves adding a flocculant to the waste liquid to capture and co-precipitate radioactive materials. The ion exchange method is a method in which the main radioactive substances in waste liquid exist as cations and anions, and these are adsorbed and removed using an ion exchange resin. Although the above methods are effective for treating large amounts of low-level radioactive waste, they are not suitable for treating high-level radioactive waste because of their low decontamination coefficients.

The evaporative concentration method evaporates and separates a large amount of water from the waste liquid.

This method allows radioactive substances to remain in the waste liquid.

This method is much more expensive than the above methods and is suitable for decontaminating high-level radioactive waste liquid.

Currently, radioactive waste fluid generated in facilities handling radioactive materials is generally concentrated using this method, mixed with cement or asphalt, and then stored in drums. As a treatment method for this waste liquid, a device has been proposed in which it is dried with a centrifugal thin film dryer and solidified with asphalt (see Japanese Patent Publication No. 52-24200). The asphalt tank is mixed using the rotating shaft of the centrifugal thin film dryer, and during normal operation, the powder produced by the centrifugal thin film dryer is directly solidified with asphalt, and when the centrifugal thin film dryer is operating abnormally, it is not leaked. The waste liquid produced by the plant is also collected in an asphalt tank so that it can be assimilated.

In this device, the unevaporated liquid flowing out of the dryer must be directly received in the asphalt tank, and the water must be evaporated on the surface of the asphalt layer, which slows down the processing speed. To prevent this, the amount of waste liquid supplied is controlled by detecting the moisture content of the dry powder in the waste liquid. However, since moisture detectors come into direct contact with dry powder, they require frequent maintenance to maintain their functionality.

The present invention was proposed to solve the above problems, and provides a cylindrical container body having a substantially vertical heating surface on its circumference and a steam outlet at the top.

a liquid to be treated inflow nozzle provided at an angle above the heating surface;
It is rotatably installed in the container body, and its outer peripheral surface slides into contact with the heating surface, and its lower end follows the plurality of scrapers preceding the upper end in the rotational direction and faces the heating surface. A drug injection nozzle that sprays drugs.

A funnel-shaped hopper is disposed at the bottom of the container body with its upper edge appropriately spaced apart from the heating surface to receive the scale scraped off the heating surface by the scraper. A rotary blade that works in conjunction with a scraper that scrapes down the scale that has accumulated on the hopper surface.

connected to the bottom of the container main body and formed to have a larger diameter than the heating surface: a container for receiving unevaporated liquid that surrounds the hopper and flows down the heating surface through a gap with the upper edge of the funnel-shaped hopper. It is characterized by a waste liquid concentration and solidification device consisting of an evaporation liquid chamber and a container connected to the lower edge of the hopper to receive the scale scraped off from the hopper, and its purpose is to eliminate any control circuits such as the automatic control described above. It is an object of the present invention to provide a waste liquid concentration and assimilation device that can dry waste liquid with substantially constant treatment efficiency not only in steady operation but also in irregular operation.

With the above configuration, the present invention can efficiently concentrate and assimilate radioactive waste liquid and has a high assimilation rate. Concentration and assimilation operations do not require automatic control or other control circuits, and do not require complicated maintenance. Furthermore, since it is a sealed type, even radioactive waste liquid containing volatile nuclides can be concentrated and solidified, resulting in a high decontamination coefficient.

Even when using asphalt as a fixing agent.

Since almost no unevaporated water enters the asphalt, it achieves effects such as high processing speed.

The most preferred embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 3.

The heating surface 7 of the container body 1 is a substantially vertical surface, and a steam jacket 5 is provided on the outer peripheral surface of the heating surface 7.
The liquid to be treated 17 is mixed with the medicine 37a injected from the medicine nozzle 36a by the ejector 35, and enters the container body 1 from the nozzle 4.

The chemical 37a uses water glass or a solidification aid.

The nozzle 4 is parallel to the plane in contact with the heating surface 7, and is provided horizontally or so that the joint portion with the heating surface is slightly upward. 2 represents the motor, and 33 represents the goo. Inside the container body 1, there is a tubular rotating shaft 6a, and a plurality of scraper arms 18 attached around the shaft. A spray nozzle 40 is provided at the tip of the scraper arm 18, and a scraper 8 that is driven in advance of the spray nozzle 4o is fixed thereto. The rotating shaft 6a is the rotating bearing 1
It is connected to the lower rotating shaft 6b via 9. 2o is a support arm of the rotary bearing 19.

Further, the rotating shaft 6a is connected to a medicine nozzle 36b for pouring a medicine 37b through a rotary joint 38 located outside the container body l.

The rotating shafts 6a and 6b are rotated by the motor 2 via a pulley 33 that is firmly connected to the rotating shaft 6a.

The drug 37b is a solidification aid or water glass.

When the liquid to be treated 17 is a solution containing uranium, the solidification aid may be an inorganic acid, an organic acid, or an alkali carbonate.

Using carbon dioxide gas or alkaline earth metal salts.

If the liquid to be treated 17 is waste liquid from another radioactive waste handling facility, in addition to boric acid, borates, phosphoric acid, primary phosphates, and aluminum salts, sulfite or sulfites, thiosulfates, - Carbon oxide, sulfur dioxide, hydrogen sulfide or sulfides, aldehyde compounds, monosaccharides, reducing oligosaccharides, reducing organic acids or reducing organic acid salts are used.

A plurality of scraper arms 18 and scrapers 8 are arranged in the vertical direction, and the vertically adjacent scraper arms 18 and scrapers 8 are connected to each other by a rotation axis 6.
It is placed at a predetermined angle with respect to a. Usually, they are arranged so that the angle is about 180°.

The vertical width of the heating surface 7 scraped by the scraper 8 is such that its lower end overlaps with a part of the lower end or upper end of the vertical width of the heating surface 7 scraped by the upper or lower adjacent scraper 8. , are arranged at a predetermined angle (usually 5 to 15 degrees) with respect to the vertical line so as to be in front of the upper end thereof. Further, a plurality of scraper arms 18 and scrapers 8 may be provided at the same horizontal position around the rotation axis at predetermined intervals.

21 is a steam inlet into the steam jacket 5, 2
2 is a steam drain outlet provided at the bottom of the steam jacket 5, and 3 is an evaporative vapor outlet provided at the top of the container body l. 23 is a non-evaporation chamber formed at the bottom of the container body 1 and has an inner diameter larger than the inner diameter of the container body 1; 24 is an unevaporated liquid outlet provided in the non-evaporation chamber 23; and 25 is a part of the container body from the unevaporated liquid chamber 23. The hopper is a funnel-shaped hopper that is inserted into the hopper and opens upward, and the upper surface of the opening is positioned above the unevaporated liquid chamber 23. The inner diameter of the top of the hopper 25 is formed to be approximately the same diameter as the inner diameter of the heating surface 7, and its outer periphery is arranged to provide an appropriate gap between the heating surface 7 and the side wall of the unevaporated liquid chamber 23. has been done. 26
is a rotary blade provided along the inner surface of the hopper 25, and is firmly connected to the one-rotation shaft 6b. The rotating blade 2b is in close contact with the upper side surface of the top of the oblique part 25 on the inner surface of the hopper.

27 a and 27 b are dampers that hang down from the upper and lower ends of a cylindrical pressure regulating chamber 28 that communicates with the lower part of the hopper 25 . The solidifying device 29 is connected to the pressure regulating chamber 28 . 12 is asphalt), 30 is an asphalt supply nozzle, and 31 is a solidified material outlet.

13 is a heater, and 32 is a solidification device motor.

It is also possible to introduce the liquid to be treated 17 directly into the container body I from the nozzle 4 as shown in FIG. The other structures are exactly the same as those in FIGS. 1 to 3. In this case, it is necessary to add the solidification aid to the liquid to be treated 17 before the liquid to be treated 17 is supplied to the container body 1. As assimilation aids, those mentioned above can be used in the interstices.

Water glass is used for drug 37.b.

The substantially vertical heating surface 7 is heated by steam blown from the steam port 21. Liquid to be treated 17
is mixed with the medicine 37a injected from the medicine nozzle 36a by the ejector 35 and sent from the nozzle 4 to the heating surface 7 of the container body 1.
It flows downward, turning along the circumferential surface of the surface. On the other hand, the chemical 37b is sprayed from the nozzle 36b through the rotary joint AS, the rotating shaft 6a, and the inner holes of the plurality of scraping arms 18, and from the injection nozzle 40 at the tip of the arm to the liquid to be treated on the heating surface 7. It is squirted and applied evenly. At this time, the water contained in the liquid to be treated 17 immediately turns into steam and is discharged from the steam outlet 3, and the solid substances are the chemicals 37a and 3.
7a.

Due to the interaction between the chemical agent 37b and the heat, it is immediately covered with a film of polymerized silicic acid, separated from the water, and eventually evaporated to dryness.

The scraper 8 is connected to the rotating shaft 6 by the motor 2 and the pulley 33.
a and the screener (while rubbing the heating surface 7 via the arm 18, return to the original position once, scrape off the dry scale 9 that is the evaporated solid matter of the liquid to be treated 17, and then rub the surface of the screener z8 one after another) 2 moves upward and toward the center of the container body 1 in a combined direction, and eventually falls downward so as to overflow from the surface of the crevice 8.

The scale 9 that fell downward - 2 falls into the hora 25 and is sent further downward by the two-rotation blade 26.

By sequentially opening and closing the dampers 27a and 27b, the liquid passes through the pressure regulating chamber 2B and falls into the solidification device 29.

On the other hand, the unevaporated liquid that fell down through the heated tube 7.

Since the side wall of the unevaporated liquid chamber 23 has a larger diameter than the inner diameter of the heating surface 7, the unevaporated liquid falls against this side wall as shown by the arrow 34, does not enter the hopper 25, but accumulates in the unevaporated chamber 23, and passes through the outlet 24. is discharged. Unevaporated 't7. The liquid is immediately mixed with the liquid to be treated 17 by a transfer means such as a pump, and is caused to flow into the container body 1 again.

In the assimilation device 29, the scale 9 is mixed with the asphalt 12 introduced from the nozzle 30 by the heater 13, heated, and then kneaded by the motor 32.
It solidifies when discharged from the tank, filled into a container such as a drum, and left to cool.

Note that the two-stage dampers 27a and 27b and the pressure regulating chamber 28
Instead, a rotary feeder or other means can be used as long as it can feed the scale downward while maintaining the inside of the container body 1 at a predetermined degree of vacuum. Furthermore, if there is no need to maintain a vacuum, there is no need to provide a damper and a pressure regulating chamber.

Further, the assimilation device 29 can be replaced with a cement solidification or vitrification device in addition to the asphalt solidification device.

Furthermore, if the radioactive material is very small, the assimilation device 29 may be omitted, and the container may be replaced with a closed container such as a drum and the scale may be directly filled.

Next, the effects of this embodiment will be listed.

(1) By arranging the nozzle 4 parallel to the plane in contact with the heating surface 7 and with the inlet facing horizontally or slightly upward, the liquid to be treated can be given a swirling flow on the heating surface 7 to the liquid to be treated 17. 17 can be efficiently dispersed.

(2) Since the inflow direction of the liquid to be treated 17 and the moving direction of the scraper 8 are the same, the dispersion of the liquid to be treated 17 is not hindered.

(3) By arranging the vertical width of the scraper 8 to scrape the heating surface 7 so that it overlaps with the width of each scraper 8 adjacent above or below, a new heating surface to which scale 9 is not attached is removed. This means that new heating surfaces to which scale 9 is not attached are constantly prepared, and the evaporation rate is extremely high.

14) By arranging the scraper 8 at a predetermined angle with respect to the vertical line so that its lower end is ahead of its upper end in the advancing direction, the retention time of the scraped scale 9 is increased, and the scale is Further reduce the water content in step 9.

(5) The inner diameter of the heating surface and the top of the funnel-shaped hopper are formed to be approximately the same diameter, and the unevaporated liquid chamber is provided at the bottom with a larger diameter than the heating surface. The removed scale easily falls into the hopper.

The unevaporated liquid flows along the side wall of the unevaporated liquid chamber from the heating surface and flows down to the unevaporated liquid without falling into the hopper, so that the scale and the unevaporated liquid can be automatically separated.

(6) To constantly stir the inside of the hopper with rotating blades.

It can evaporate the moisture attached to the scale.

(7) By providing a damper and a pressure regulating chamber, the inside of the evaporator can be made into a vacuum type, and radioactive substances will not leak to the outside, so safety can be improved. In addition, waste liquid containing radioactive substances that easily volatilize at high temperatures can also be treated.

(8) By disposing the injection nozzle 40 that follows the ejector 35 and the scraper 8, water glass and solidification aid can be separately injected toward a new heating surface to which scale 9 is not attached. The injection amount of each chemical can be freely controlled according to the evaporation drying rate on the surface 7. In addition, when using a gaseous substance that is difficult to dissolve in water as a solidification aid, it can be sprayed directly from the spray nozzle 40 onto the liquid to be treated on the heated surface, so the liquid to be treated can be efficiently evaporated without increasing the amount of evaporated liquid. Can be dried.

(9) By adding water glass and a solidification aid to the liquid to be treated, in combination with the effect of heating and concentration, the solidification rate is significantly accelerated and efficiency is increased.

Solid matter and radioactive substances in the screaming fluid are rapidly covered with polymerized silicic acid and become pellets.

Water in the liquid is easily evaporated and separated.

01) Since the pelleted scale is covered with polymerized silicic acid, it does not dissolve again even if it comes into contact with the unevaporated liquid, so the amount of solids in the unevaporated liquid is extremely low.

The rate of evaporation to dryness therefore increases.

u21 The pelletized scale contains almost no moisture and crystal water. Therefore, it easily adheres to asphalt and has a high asphalt assimilation rate.

031 Polymerized silicic acid is a non-swelling gel, so it absorbs a small amount of water in asphalt and does not swell.

No gaps are created with the solidified asphalt. This makes it difficult for radioactive substances to leak out, increasing safety.

[Brief explanation of the drawing]

-A sectional view, FIG. 3 is an explanatory diagram showing the attachment state of the medicine injection nozzle and scraper in this embodiment, and FIG. 4 is an explanatory diagram showing another embodiment of the present invention. ■...Container body, 3...Steam outlet, 4...Liquid to be treated inflow nozzle, 7...Heating surface, 8...Scraper,
23...Unevaporated liquid chamber, 25...Hopper, 26...
rotating blade. 29... Solidification device, 40... Injection nozzle. 529- Figure 1 j2! 3J'

Claims (1)

[Claims] A cylindrical container body with a substantially vertical heating surface on its periphery and a steam outlet at the top; a liquid inflow nozzle for the liquid to be treated inclined at the top of the heating surface; rotatably installed in the container body. a chemical injection nozzle whose outer peripheral surface is in sliding contact with the heating surface and whose lower end follows the plurality of scrapers in the rotational direction relative to the upper end thereof and injects a chemical toward the heating surface; a funnel-shaped hopper disposed at the bottom of the container body with its upper edge appropriately spaced from the heating surface to receive falling scales scraped by the scraper from the heating surface; A rotary blade is connected to the bottom of the container body and is connected to the bottom of the container body and is formed to have a larger diameter than the heating surface, surrounds the hopper, and passes along the heating surface into the funnel-shaped blade. Waste liquid concentration solidification characterized by comprising an unevaporated liquid chamber that receives unevaporated liquid flowing down through a gap with the upper edge of the hopper, and a container that is connected to the lower edge of the hopper and receives scale scraped off from the hopper. Device.