JPS604897A - Waste liquor concentrating solidifying treating 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 present invention relates to an apparatus for concentrating and assimilating waste liquid.

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 is a method in which a flocculant is added to waste liquid to capture and co-precipitate radioactive substances. 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.

The above method is effective for treating large amounts of low-level radioactive waste liquid, but the decontamination coefficient is low (and it is not suitable for treating high-level radioactive waste liquid).

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 suitable for decontaminating high-level radioactive waste liquids because the removal coefficient is much higher than that of the above method because nonionic nuclides can also be separated from water.

Currently, radioactive waste fluid generated at facilities handling radioactive materials is generally concentrated using this method, mixed with cement or asphalt, solidified, and then filled into drums and stored. As a method for treating this waste liquid, an apparatus has been proposed in which it is dried in a centrifugal thin film dryer and solidified with asphalt (see Japanese Patent Publication No. 52-24200).

This equipment has an asphalt solidifying machine installed at the bottom of the centrifugal thin film dryer, and mixes the asphalt in the asphalt tank using the rotating shaft of the centrifugal thin film dryer.During steady operation, the powder produced by the centrifugal thin film dryer is directly mixed. The asphalt tank is designed to receive and assimilate waste liquid that solidifies with asphalt and flows out during abnormal operation of the centrifugal thin film dryer.

The water must be directly received into 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 solves the above-mentioned problems, and consists of a cylindrical container body equipped with a substantially vertical heating surface on its circumferential surface and a steam outlet at the top; A mixing chamber in which the liquid to be treated and water glass are mixed just before reaching the heating surface, and a scraper rotatably installed in the container body, the outer peripheral surface of which slides into contact with the heating surface, and the lower end of which is in front of the upper end. , a hopper disposed at the lower part of the container body with its upper edge appropriately spaced from the heating surface to receive scales scraped and falling from the upper aC heating surface by the scraper; A rotary blade that works in conjunction with the scraper that scrapes scale accumulated on the hopper surface downward, is connected to the bottom of the container body and is formed with a larger diameter than the heating surface, surrounds the hopper, and passes along the heating surface to the heating surface. The hopper is characterized by comprising an unevaporated liquid chamber for receiving unevaporated liquid flowing down through a gap with the bead of the funnel-shaped hopper, and a container connected to the lower edge of the hopper for receiving scale scraped from the hopper. It is characterized by a waste liquid concentration and solidification treatment equipment that does not require any control circuits such as the above-mentioned automatic control, and the processing speed is almost constant not only in steady operation but also in abnormal operation, and the radioactive material can be dried. The purpose is to provide a waste liquid concentration and assimilation treatment device.

By adopting the configuration shown in 8C above, the present invention can efficiently concentrate and assimilate radioactive waste liquid and has a high assimilation rate. Control circuits such as automatic control are not required for concentration and solidification operations. Since it is a sealed type, even radioactive waste liquid containing volatile nuclides can be concentrated and assimilated, resulting in a high decontamination coefficient. Even when asphalt is used as a fixing agent, the processing speed is high because almost no unevaporated water enters the asphalt.

It has the following effects.

The present invention will be described below with reference to the most preferred embodiments.

In FIGS. 1 to 3, the heating surface 7 of the circular container main body l is a substantially vertical surface, and a steam jacket 6 is provided on the outer peripheral surface of the heating surface 7, and the liquid to be treated 21 is passed through the ejector. At step 89, the chemical liquid 41 injected from the chemical liquid nozzle 40 is mixed in the mixing chamber 4 and enters the heating surface 7. The mixing chamber 4 is disposed parallel to the plane in contact with the heating surface 7, horizontally or slightly upwardly, and also serves as a nozzle. 2 is a motor, 87 is a pulley, and inside the container body l there are a rotating shaft 6a,
Multiple scraper arms 2 around the axis
2. A scraper 8 joined to the tip of the scraper arm 22 is provided, and one rotation shaft 6a is connected to a lower rotation shaft 6b via a rotation bearing 28, so that these can rotate. 24 is a support arm of the rotary bearing 23.

A plurality of scraper arms 22 and scrapers 8 are arranged in the vertical direction, and the vertically adjacent scraper arms 22 and scrapers 8 are positioned at a predetermined angle (usually 180°) with respect to the rotation axis 6. Deploy it like this.

The vertical width of each scraper 8 scraping the heating surface 7 overlaps with a part of the lower end or the upper end of the vertical width of the upper or lower adjacent scraper 8 scraping the heating surface 7, respectively. 8 is placed. Further, the scraper 8 is tilted at a predetermined angle with respect to the vertical line so that its lower end precedes its upper end in the direction of movement while closely contacting the heating surface 7 .

A plurality of scraper arms 22 and scrapers 8 may be provided at the same horizontal position around the rotation axis at predetermined intervals.

25 is the steam population in the steam jacket 5, 26
3 is a steam drain outlet provided at the bottom of the steam jacket 5, and 3 is an evaporative steam outlet provided at the top of the container body l.

Reference numeral 27 denotes an unevaporated liquid chamber formed at the bottom of the heating surface 7 and having an inner diameter larger than the inner diameter of the container body 1.

28 is an unevaporated liquid outlet provided in the unevaporated liquid chamber 27.

A funnel-shaped hopper 29 is inserted into the heating surface 7 from the unevaporated liquid chamber and opens upward, and the upper surface of the opening is positioned above the unevaporated liquid chamber 27. Hopper 2
The inner diameter of the top of the heating surface 9 is formed to be approximately the same as the inner diameter of the heating surface 7.

Its outer periphery is provided so as to form an appropriate gap between the heating surface 7 and the side wall of the unevaporated liquid chamber 27 .

80 is a rotary blade provided along the inner surface of the hopper 29, and is firmly connected to the two-rotation shaft 6b.

The rotary vane 80 is not only in close contact with the inclined portion of the inner surface of the hopper, but also in close contact with the top-E transparent surface of the hopper 29.

81a and 81b are dampers tR hanging from the upper and lower ends of the cylindrical pressure regulating chamber 82 connected to the lower part of the hopper 29. 8
8 is an assimilation device connected to a pressure regulating chamber 82.

14 is asphalt, 84 is an asphalt supply nozzle,
85 is a solidified material outlet, 15 is a heater, and 86 is a solidifying device motor.

The substantially vertical heating surface 7 is heated by steam blown from the steam port 25. Liquid to be treated 21
is the chemical liquid 4 injected from the chemical liquid nozzle 40 by the ejector 89.
1 and enters the heating surface 7 from the mixing chamber 4.

The liquid to be treated 21 is mixed with a solidification aid in advance.

When the liquid to be treated 21 is a solution containing uranium, an inorganic acid, an organic acid, an alkali carbonate, an alkaline earth metal salt, etc. are used as the solidification aid, and the solidification aid is used to treat the treated liquid 21 or disease treatment liquid 2 th; M rat substance. In the case of waste liquid from handling facilities, in addition to boric acid, borates, phosphoric acid, monophosphates, and aluminum salts, sulfite or sulfites.

Thiosulfates, carbon oxides, sulfur dioxide, hydrogen sulfide or sulfides, aldehyde compounds, monosaccharides, reducing oligosaccharides, reducing organic acids or reducing organic acid salts are used. Water glass is used as the chemical solution 41.

The liquid to be treated 21 flows down from the mixing chamber 4 along the heating surface 7 while swirling along the surface circumference. At this time, due to the chemical solution 41, the solidification aid added in advance to the liquid to be treated 21, and heating, the solids in the liquid to be treated 21 are immediately covered with a polymerized silicic acid film and begin to be assimilated, and are separated from the water. The water is heated by the heating surface 7 and immediately turns into steam at the steam outlet 8.
Emit more. The scraper 8 uses the motor 2 and pulley 37 to scrape the heated surface 7 through the rotating shaft 6a and the scraper arm 22, and scrapes off the dry scale 10 that is the evaporated solid matter of the liquid to be treated 21. It moves on the surface in the combined direction of the upward direction and the direction of the rotation axis 6a, and eventually overflows the surface of the scraper 8 and falls downward. The lower scraper 8 also acts in the same way.

The scale 10 that has fallen downward is collected in a hopper 29.

The scale 10 accumulated in the hopper 29 is sent downward by the rotating blade 80, passes through the pressure regulating chamber 32, and flows down to the solidification device 3B by sequentially opening and closing the damper 81a and the damper 81b.

On the other hand, since the side wall of the unevaporated liquid chamber 27 has a larger diameter than the inner diameter of the heated surface 7, the liquid that has not evaporated and fallen along the heating surface 7 falls along this side wall as shown by the arrow 88, and falls into the hopper 29. The unevaporated liquid does not enter the liquid and accumulates in the unevaporated liquid chamber 27, and is discharged via the outlet 28.

The unevaporated liquid is immediately mixed with the liquid to be treated 21 by a transfer means such as a pump, and is caused to flow into the container body l again.

In the assimilation device 88, asphalt 1 is introduced from the nozzle 84.
4 and scale lO are heated by the heater 15 and then mixed and stirred by the motor 36, discharged from the solidified material outlet 85, filled into a container such as a drum can, and left to cool to solidify.

Note that the two-stage dampers 81'a and 81b and the pressure regulating chamber 32
Instead, a 20-tally feeder or other means may be used as long as it is capable of feeding the scale downward while maintaining the inside of the container body 1 at a predetermined degree of vacuum. Further, if there is no need to maintain a vacuum, it may not be provided.

Further, the solidification device 88 can be replaced with a cement assimilation method or a glass assimilation method in addition to the asphalt assimilation method.

Furthermore, if there is almost no radioactive material, the solidification device 83 may be omitted, and the container may be directly replaced with a closed container such as a drum and filled with scale directly.

Next, the effects of this embodiment will be listed.

(1) By mixing the liquid 21 to be treated with the chemical liquid 41 in the ejector 89 immediately before it flows into the container body 1.

Precipitation of the chemical solution 41 (water glass) inside the tube can be prevented.

(2) By arranging the mixing chamber 4, which serves as a nozzle, in 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 21 can be swirled around the heating surface 7. Since the flow is provided, the liquid to be treated 21 can be efficiently dispersed.

(3) Since the inflow direction of the to-be-treated M21 and the moving direction of the scraper 8 are the same, the dispersion of the to-be-treated liquid 21 is not hindered.

(4) By arranging the vertical width of the heating surface 7 scraped by the scraper 8 so that it overlaps with the width of each scraper 8 adjacent above or below, a new heating surface to which scale 10 is not attached is removed. It has to be prepared constantly, and the evaporation rate is extremely high.

(5) By arranging the scraper 8 at a predetermined angle with respect to the vertical line so that the lower end leads in the direction of movement, the retention time of the scraped scale lO is increased;
The water content of the scale 10 is further reduced.

(6) Since the heating surface 7 and the top inner diameter of the funnel-shaped hopper 29 are formed to have approximately the same diameter, and the non-evaporation chamber 27 is provided at the bottom with a larger diameter than the heating surface, the scraper The scale scraped off in step 8 easily falls into the hopper 29, and the unevaporated liquid flows from the heating surface 7 along the side wall of the unevaporated liquid chamber 27 and falls into the hopper 29, where it flows down into the unevaporated liquid. Therefore, scale and unevaporated liquid can be automatically separated.

(7) Since the inner surface of the hopper 29 is constantly stirred by the rotary blade 8o, trace amounts of water adhering to the scale can be evaporated.

(8) By providing the dampers 81a, 81b and the pressure regulating chamber 82, the inside of the evaporation chamber can be made into a vacuum type, and radioactive substances will not leak outside, which not only improves safety.

Even waste liquid containing radioactive substances that easily volatilize at high temperatures can be treated.

(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 assimilation rate is significantly accelerated, allowing efficient evaporation and solidification.

00 The dissolved components and radioactive substances in the liquid are rapidly covered with polymerized silicic acid to form pellets, so that the water in the liquid can be easily evaporated and separated.

0υ Since the pelletized 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, and the separation efficiency increases.

(To) Since the pelletized scale contains almost no moisture or water of crystallization, it easily sticks to asphalt, resulting in a high asphalt solidification rate.

Q3 Polymerized silicic acid is a non-swellable gel, so even if it absorbs a small amount of water in asphalt, it does not swell and does not form gaps with the asphalt.

This makes it difficult for radioactive substances to leak out, increasing safety.

[Brief explanation of the drawing]

1 to 8 show one embodiment of the present invention, FIG. 1 is a vertical sectional view of the main part, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 8 is an embodiment of the present invention. It is an explanatory view showing an attachment state of the scraper in . 1... Container body, 3... Steam outlet, 4... Mixing chamber. 7... Heating surface, 8... Scraper 728... Unevaporated liquid chamber. 29...Hopper, 80...Rotating blade, 33...Solidification device 15 I"VV'VV) Figure 2 I Figure 3

Claims (1)

[Claims] A cylindrical container body with a substantially vertical heating surface on its periphery and a steam outlet at the top, and a cylindrical container body disposed at the top of the container body to separate the liquid to be treated and water immediately before the liquid to be treated reaches the heating surface. a mixing chamber for mixing glass; a scraper which is rotatably installed in the container body and whose outer peripheral surface slides on the heating surface and whose lower end precedes the upper end; A hopper is disposed at an appropriate distance from the heating surface to receive falling scales scraped by the scraper from the heating surface, and a hopper is disposed within the hopper to scrape downwardly the scale accumulated on the hopper surface A rotary blade that interlocks with the scraper and is connected to the bottom of the container main body and is formed to have a diameter larger than the heating surface, surrounds the hopper, runs along the heating surface, and passes through a gap with the upper edge of the funnel-shaped hopper. A waste liquid concentration and assimilation treatment apparatus comprising an unevaporated liquid chamber for receiving flowing unevaporated liquid and a container connected to the lower edge of the hopper to receive scale scraped off from the hopper.