JPH05126996A - Treatment of waste oil containing phosphorous - Google Patents

Abstract

PURPOSE:To burn and process radioactive waste oil containing phosphorous generated in reprocessing process of spent fuel without corroding facility and choking filters in a short time. CONSTITUTION:An organic solution containing calcium such as calcium octilate is mixed with radioactive waste oil containing phosphorous and this mixture waste oil is burned in a burning furnace 5. The burned exhaust gas is filtered in a high temperature filter charged with ceramic honeycomb and finely filtered with a HEPA filter and then discharged to the atmosphere.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating radioactive waste oil containing phosphorus generated in a spent fuel reprocessing step or the like, and radioactive waste oil containing phosphorus generated in a nuclear power plant or the like. ..

[0002]

2. Description of the Related Art Radioactive phosphorus-containing waste oil is generated because TBP (tributyl phosphate) is used as an extractant in the spent fuel reprocessing step and phosphate ester oil is used as a control oil in a nuclear power plant. To do. However, if this waste oil is incinerated as it is, there is a problem that phosphoric acid contained in the exhaust gas significantly corrodes metals and refractories. In addition, the waste oil containing phosphorus has a poor combustibility, and there is a problem that a large amount of unburned carbon is generated and the filter is immediately clogged.

Therefore, conventionally, such waste liquid was stored as it is or was made to react with calcium hydroxide in a carbonization furnace to form calcium pyrophosphate, but in the former case, there is a problem of storage space, and in the latter case. There is a problem that the reaction requires a long time and requires large equipment and complicated steps.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art by corroding equipment such as radioactive waste oil containing phosphorus generated from the reprocessing step of spent fuel and filtering the equipment. The present invention was completed in order to provide a method for treating phosphorus-containing waste oil that can be incinerated in a short time without clogging.

[0005]

The present invention made to solve the above-mentioned problems is to add radioactive organic oil containing phosphorus to an organic solution containing calcium such that the ratio of calcium to phosphorus is equal to or more than the chemical equivalent. It is characterized in that the mixed waste oil is mixed and burned in an incinerator, the combustion exhaust gas is filtered by a high temperature filter filled with a ceramic honeycomb, and further is finely filtered by an exhaust gas filter and discharged.

[0006]

The present invention will be described in more detail below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a container containing a radioactive waste oil containing phosphorus such as TBP, and the radioactive waste oil taken out of the container 1 is mixed with an organic solution containing calcium in a hopper 2. In the examples, this organic solution is calcium octylate, and is added and mixed so that the ratio of calcium to phosphorus is equal to or more than the chemical equivalent. For example, 33.2 kg of calcium octylate having a calcium content of 5% by weight may be added to waste oil containing 10 kg of TBP and 18 kg of dodecane. The molar ratio of calcium to phosphorus in this case is 1.1 times. The mixed waste oil is uniformly stirred in the stirring tank 3 and sent to the incinerator 5 by the pump 4.

As described above, since the waste oil containing phosphorus is not easily combusted, the incinerator 5 having a special structure is used in the embodiment.
Is used. That is, as shown in FIG.
Has a water-cooled jacket structure furnace wall, and mixed waste oil with calcium octylate is dropped from a charging nozzle 6 near the furnace bottom. Further, a combustion air supply cylinder 7 is provided in the center of the furnace body, and high-pressure combustion air is radially ejected in the outer peripheral direction to generate a high-speed swirling flow in the furnace. The dropped mixed waste oil accumulates on the bottom of the furnace and burns while vaporizing from the surface. Reference numeral 8 is an ignition burner.

In the embodiment, the combustion air is supplied from the combustion air supply cylinder 7 in the center of the furnace body as described above. However, the combustion air supply nozzle is tangential to the furnace wall or in the furnace central axis direction. May be provided. In addition to burning the mixed waste oil by the dropping method, it can be burned by a rotary burner or a spray combustion burner. Further, the water-cooled jacket structure of the furnace wall has an advantage that a thick refractory can be eliminated and the furnace body can be made compact, but the invention is not necessarily limited to this.

When the mixed waste oil is burned in the incinerator 5 in this manner, phosphorus in the waste oil reacts with calcium octylate to generate calcium pyrophosphate. Therefore, Figure 1
As shown in, the combustion exhaust gas from the incinerator 5 is guided to the high temperature filter 10 filled with the ceramic honeycomb 9 and filtered.
The ceramic honeycomb 9 in the high temperature filter 10 is shown in FIG.
As shown in FIG. 4, the vertical holes 11 of the honeycomb structure made of porous ceramics such as mullite or cordierite are alternately sealed by the sealing materials 12 on both end faces, and the high temperature combustion flowing in the direction of the arrow The calcium pyrophosphate powder and dust in the exhaust gas are filtered when passing through the partition walls, and only the gas is discharged. The ceramic honeycomb 9 also has a function of causing secondary combustion of unburned carbon, and has a large internal surface area, so sufficient filtration and secondary combustion are possible with compact equipment. Figure 1
Reference numeral 13 is a backwash nozzle.

Cooling air is mixed with the gas filtered by the high temperature filter 10 by an air mixing valve 14,
It is cooled to about 200 ° C. After that, it is further finely filtered by an exhaust gas filter 15 called a HEPA filter, and is discharged into the atmosphere. Since the HEPA filter is a filter using filter paper, it is preferable to cool the gas to about 200 ° C. as in the example.

[0011]

As described above, according to the method for treating phosphorus-containing waste oil of the present invention, phosphorus-containing waste oil and the like generated in the spent fuel reprocessing step are mixed with an organic solution containing calcium and incinerated. Since it is burnt in the furnace 5, it is possible to incinerate without generating corrosive phosphoric acid. Further, although waste oil containing phosphorus has a poor combustibility, it can be combusted without trouble according to the combustion method of the present invention, and unburned carbon is secondary in the high temperature filter 10 filled with the ceramic honeycomb 9. Since the combustion gas can be burned and the combustion gas can be efficiently filtered, there is an advantage that the high temperature filter 10 is less likely to be clogged and large equipment is not required. Therefore, the present invention, as a method of treating phosphorus-containing waste oil that solves the conventional problems, has a great contribution to the industrial development.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an example of the present invention.

FIG. 2 is a sectional view of an incinerator.

FIG. 3 is a sectional view of a ceramic honeycomb.

FIG. 4 is a plan view of the ceramic honeycomb of FIG.

[Explanation of symbols]

 5 Incinerator 7 Combustion air supply tube 9 Ceramic honeycomb 10 High temperature filter 15 Exhaust gas filter

Claims (2)

[Claims] 1. A radioactive waste oil containing phosphorus is admixed with an organic solution containing calcium so that the ratio of calcium to phosphorus is equal to or more than the chemical equivalent, and the mixed waste oil is burned in an incinerator to produce combustion exhaust gas as a ceramic. A method for treating phosphorus-containing waste oil, which comprises filtering with a high-temperature filter filled with a honeycomb, and further fine-filtering with an exhaust gas filter and discharging. 2. The method for treating phosphorus-containing waste oil according to claim 1, wherein the mixed waste oil is dropped and burned in an incinerator having a water-cooled jacket structure.