JP7628980B2 - Cement solidification equipment - Google Patents

Description

The present invention relates to a cement solidification device.

Cement solidification is one of the methods for treating radioactive waste discharged from nuclear power plants, etc. Cement solidification is a method in which cement is poured into radioactive waste contained in drums to solidify it.

An example of a cement solidification device is the following Patent Document 1. Patent Document 1 describes a radioactive waste treatment facility that can perform injection solidification (a method in which waste is filled into drums in advance, and then a solidification material is injected from above to solidify) and kneading solidification (a method in which waste and a solidification material are kneaded and solidified) in a single facility, and that reduces the generation of radioactive secondary waste. Patent Document 1 states, "Because radioactive waste is input into the waste input kneading means during kneading and solidification, the washing waste liquid becomes radioactive secondary waste. However, because this waste input kneading means can be an in-drum system, it is sufficient to wash, for example, only the kneading blades, and the amount of radioactive secondary waste generated can be reduced."

JP 2001-174588 A

The above-mentioned Patent Document 1 describes an in-drum kneading type cement solidification equipment that has the characteristic of eliminating the need for a mechanism for receiving and supplying washing water by discharging the washing water after mixing into the drum of the next batch. However, with the in-drum kneading type cement solidification equipment described in Patent Document 1, when the waste to be treated is liquid, the "amount of water that can be mixed with cement = liquid waste + washing water" is calculated, so there is an issue that the amount of liquid waste that can be treated is reduced by the amount of washing water.

In view of the above circumstances, the object of the present invention is to provide a cement solidification device that can reduce the amount of waste generated by increasing the amount of liquid waste filled per drum and reducing the number of discarded drums.

One aspect of the present invention for solving the above problems is a cement solidification apparatus comprising: a filter device that filters solids in liquid waste; a filtration residue supplying unit that supplies the filtration residue separated by the filter device to a washing tank; a cleaning water supplying unit that supplies the filtrate that has passed through the filter device to the washing tank as cleaning water; a cement feeding unit that feeds cement into the washing tank; and a kneader that kneads the filtration residue and cement fed into the washing tank.

More specific configurations of the present invention are described in the claims.

The present invention provides a cement solidification device that can reduce the amount of waste generated by increasing the amount of liquid waste filled per drum and reducing the number of discarded drums.

Problems, configurations and advantages other than those described above will become clear from the description of the embodiments below.

Schematic cross-sectional view of the cement solidification apparatus of Example 1 Schematic cross-sectional view of the cement solidification apparatus of Example 1 Schematic diagram of a spray nozzle of a washing water supply unit of a cement solidification apparatus according to Example 2. Schematic diagram of dead-end filter Crossflow filter schematic diagram Flow diagram of the solidification process of the cement solidification apparatus of the first embodiment Cross-sectional schematic diagram of a conventional cement solidification device Flow diagram of solidification process in a conventional cement solidification device

The following describes an embodiment of the present invention with reference to the drawings.

1 and 2 are schematic cross-sectional views of a cement solidification apparatus according to Example 1. As shown in Fig. 1 and 2, the cement solidification apparatus 100 of the present invention is an in-drum type (a method in which the material to be treated and cement are mixed and injected in one drum), and includes a filter device 11 for filtering solids in a liquid waste 3 that is the material to be treated, a filter residue supplying section 8 for supplying the filter residue, which is the solids removed through the filter device 11, to a drum (washing tank) 6, a washing water supplying section 10 for supplying the filtrate passed through the filter device 11 to the drum 6 as washing water, a cement injection section 1 for injecting cement into the drum 6, and a kneader 5 for kneading the filter residue and cement injected into the drum 6.

The cleaning water supply unit 10 is equipped with a cleaning nozzle 2, and supplies the filtrate (liquid waste) from which solids have been removed through a filter device 11 as cleaning water from the cleaning nozzle 2 to clean the kneader 5.

The drum 6 is moved by a moving mechanism 7 such as a conveyor (in the direction of the right arrow in Figure 2) to a position directly below the cement solidification device 100 (position A in Figure 2), where it is lifted by a lifting mechanism 20, and liquid waste and cement are added and mixed from the cement solidification device 100. After mixing, the lifting mechanism 20 lowers the drum 6 onto the moving mechanism 7, and the drum 6 containing the cement 30 with the liquid waste enclosed therein is moved again (in the direction of the right arrow in Figure 2). In this way, by sending the drums 6 sequentially by the moving mechanism 7, continuous cement solidification processing can be achieved.

As described above, the cement solidification apparatus 100 of the present invention uses the liquid waste 3 as cleaning water. In order to use the liquid waste 3 as cleaning water, the liquid waste 3 is filtered using a filter device 11 before being poured into a drum can 6, and the liquid waste 3 is separated into a filtration residue and a filtrate. The filtration residue is then poured into the drum can 6 using a filtration residue supply unit 8, while the filtrate is supplied to the cleaning nozzle 2 as cleaning water by a cleaning water (filtrate) supply unit 10.

FIG. 6 is a flow diagram of the solidification process of the cement solidification device of the first embodiment. As shown in FIG. 6, an empty drum can 6 is carried to a position (position A in FIG. 2) directly below the cement solidification device 100 (S1). Prior to the introduction of liquid waste and cement into the drum can 6, the liquid waste 3 is filtered by the filter device 11 and separated into a filtrate (washing water) and a filtration residue (S21 to S23). The filtrate is supplied as washing water from the washing water supply unit 10 to the kneader 5 to wash the kneader 5 (S2). The filtration residue is introduced into the drum can 6 from the filtration residue supply unit 8 (S3). Then, cement is supplied to the drum can from the cement introduction unit 1 (S4) and kneaded by the kneader 5 (S5). Then, the drum can 6 containing the cement 30 that has been solidified and trapped in the liquid waste is moved (S6).
According to the above-mentioned configuration of the cement solidification apparatus 100 of this embodiment, since liquid waste is used as the washing water, the amount of liquid waste packed in one drum can be increased, and the number of waste bodies generated can be reduced.

Figure 7 is a schematic cross-sectional view of a conventional cement solidification device, and Figure 8 is a flow diagram of the solidification process of the conventional cement solidification device. As shown in Figures 8 and 9, in the conventional cement solidification device, the washing water used to wash the kneader 5 is discharged into the drum can 6 of the next patch, thereby eliminating the need for a washing water receiving and supplying section. However, when the waste to be treated is liquid waste 3, there is a problem in that the more the amount of washing water increases, the less liquid waste 3 can be mixed with cement.

Figure 3 is a schematic diagram of the spray nozzle of the washing water supply section of the cement solidification device of Example 2. The improvement in washability when the washing water supply port is a spray nozzle will be explained below with reference to Figure 3. By using a spray nozzle 12 for the washing water supply port, it becomes possible to efficiently wash the planetary blades 13 and high-speed blades 14 that constitute the kneader 5. This reduces the amount of washing water required for washing, and improves the washability of the washing mechanism.

Figure 4 is a schematic diagram of a full-flow filtration filter, and Figure 5 is a schematic diagram of a cross-flow filter. The improvement in cleanability when a cross-flow filter is used in the filter device 11 of the cement solidification device 100 of the present invention will be explained using Figures 4 and 5.

As shown in FIG. 4, in a full-flow filtration filter as the filter 16, the membrane supply water 18 is supplied perpendicular to the filter membrane surface 16, and the membrane supply water 18 and the membrane filtered water 19 flow in parallel directions. However, with continued use of the filter, suspended matter 17 accumulates on the filter membrane surface 16, reducing the filtration efficiency. Therefore, to continue using the filter, it is necessary to periodically clean or replace the filter.

As shown in Figure 5, when a cross-flow filter is used as the filter 16, the membrane supply water 18 is supplied in a direction parallel to the filter membrane surface 16, and the membrane supply water 18 and the membrane filtrate water 19 flow in a vertical direction. This allows filtration to continue while suppressing the phenomenon in which suspended matter 17 in the membrane supply water 18 accumulates on the filter membrane surface 16.

As mentioned above, when a crossflow filter is used, it is possible to reduce the amount of filtration residue and increase the amount of filtrate. This improves the cleaning ability of the cleaning mechanism.

As explained above, according to the present invention, it has been shown that it is possible to provide a cement solidification device that can reduce the amount of waste generated by filtering the liquid waste with a filter and then reusing the filtrate as cleaning water, thereby increasing the amount of liquid waste filled per drum and reducing the number of discarded drums.

The above-mentioned embodiments and experimental examples have been described to aid in understanding the present invention, and the present invention is not limited to the specific configurations described. For example, it is possible to replace part of the configuration of the embodiments with configurations that are within the technical common sense of a person skilled in the art, and it is also possible to add configurations that are within the technical common sense of a person skilled in the art to the configuration of the embodiments. In other words, it is possible to delete, replace, or add other configurations to part of the configurations of the embodiments and experimental examples in this specification, as long as it does not deviate from the technical idea of the invention.

1...cement input section, 2...washing nozzle, 3...liquid waste, 4...washing water supply section, 5...kneader, 6...drum (washing tank), 7...moving mechanism, 8...filter residue supply section, 9...waste supply section, 10...washing water (filtrate) supply section, 11...filter device, 12...spray nozzle, 13...planetary blade, 14...high-speed blade, 15...washing area, 16...filter membrane surface, 17...suspended matter, 18...membrane supply water, 19...membrane filtered water, 20...lifting mechanism, 100...cement solidification device.

Claims (3)

A cement solidification apparatus comprising: a filter device that filters solids in liquid waste; a filtration residue supplying unit that supplies the filtration residue separated by the filter device to a washing tank; a cleaning water supplying unit that supplies filtrate that has passed through the filter device to the washing tank as cleaning water; a cement feeding unit that feeds cement into the washing tank; and a kneader that kneads the filtration residue and cement fed into the washing tank. The cement solidification device according to claim 1, characterized in that the washing water supply unit has a spray nozzle. The cement solidification device according to claim 1 or 2, characterized in that the filter device has a cross-flow filter.

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