JP6096526B2 - Polishing machine, contaminant removal system using the same, and contaminant removal method - Google Patents

Description

  The present invention relates to a polishing machine, a pollutant removal system using the same, and a pollutant removal method, and more particularly, a polish configured to clean soil by polishing and removing contaminants attached to the surface of soil particles. The present invention relates to a machine, a pollutant removal system using the same, and a pollutant removal method.

  Since the accident at the Fukushima Daiichi Nuclear Power Station, a large amount of radioactive material such as radioactive cesium has been scattered and infiltrated into the soil. In particular, radioactive cesium adheres to the surface of soil particles at a depth of about 3 cm from the ground. In situations where the surface layer of the soil flows due to weather conditions such as rain, radioactive cesium may flow along with the soil particles. For this reason, it is necessary to scrape the soil of a predetermined depth and remove radioactive cesium adhering to the surface of the soil particles at the shaved portion.

Removal of the particle surface such as soil particles is performed by causing the particles to collide with each other and polishing the particle surface. As a method for polishing and removing the particle surface, there are various treatment methods such as a mechanical treatment method and a cavitation treatment method. As a mechanical processing method, there is a ball mill in which hard balls made of steel or ceramic and particles are put in a container and rotated to grind the particles. On the other hand, in the cavitation treatment method, a dispersion liquid containing particles to be processed is introduced into a polishing machine having a stirring mechanism, and bubbles are generated by cavitation by passing the dispersion liquid through a throttle channel provided in the polishing machine. Some are configured to polish the surface of the particles in the dispersion liquid by an impact force acting on the particles when the bubbles collapse (for example, Patent Document 1).
JP 2011-101937 A

  However, when cavitation is used as a polishing method for the particle surface, not only noise and vibration are generated from the device for polishing particles due to the impact force when the bubbles collapse, but also the device is prone to minute destruction and damage. The short life of the device is a problem. Therefore, methods other than the use of cavitation are desirable, but when treating soil particles that are contaminated with radioactive materials such as radioactive materials, only the surface of the contaminated particles is ground and removed without grinding the soil particles. It is important to apply a suitable impact force to the particles. For this reason, it is necessary to configure the polishing machine so that an appropriate impact force can be applied to the particles to be processed.

  In view of the problems as described above, the present invention provides a polishing machine configured to remove contaminants attached to the surface of soil particles, a contaminant removal system using the same, and a contaminant removal method. With the goal.

  In order to solve the above problems, a polishing machine according to the present invention includes an injection nozzle that injects a fluid containing soil particles pressurized by a pressurizing unit, and a diameter larger than that of the injection nozzle that is provided downstream of the injection nozzle. An injection pipe, a particle accumulation portion (for example, the front pipe 14 in the embodiment) that is provided downstream of the injection pipe and is recessed so that a part of soil particles contained in the fluid can be deposited, and an injection nozzle and an injection pipe It is provided with an air introduction port that is provided between and can introduce air into the injection pipe, and the soil particles flowing through the injection pipe collide with the wall surface formed by the soil particles accumulated in the particle accumulation portion, The surface of the collided soil particles is removed by polishing.

  In the polishing machine configured as described above, a tubular power tube having an outer diameter smaller than the inner diameter of the injection pipe and an inner diameter larger than the injection nozzle is provided substantially concentrically with the injection pipe inside the injection pipe. The power tube preferably extends in the longitudinal direction of the spray tube so that soil particles can collide with the deposition surface.

  Furthermore, in the polishing machine configured as described above, it is preferable that the spray pressure of the sludge fluid sprayed from the spray nozzle is a pressure of 0.5 to 1.0 MPa.

  On the other hand, in order to solve the above problems, a pollutant removal system according to the present invention mixes and polishes a polishing machine having the above-described configuration, soil particles containing a pollutant and having a predetermined particle diameter or less, and slurry. A mixing tank, a pressurizing means for supplying slurry from the mixing tank to the polishing machine (for example, the pressure pump 3 in the embodiment), and the surface of the soil particles polished and removed by the polishing machine as a contaminant Means (for example, a classification plant 5 in the embodiment).

  Moreover, the contaminant removed by the contaminant removal system of the said structure is radioactive cesium, for example.

  On the other hand, a soil particle polishing method according to the present invention for solving the above problems includes an injection nozzle for injecting a fluid containing soil particles pressurized by a pressurizing means, and an injection nozzle provided on the downstream side of the injection nozzle. A jet pipe having a larger diameter, a particle depositing portion (for example, the front pipe 14 in the embodiment) that is provided downstream of the jet pipe and in which a part of the soil particles contained in the fluid can be deposited, and a jet nozzle A fluid containing soil particles pressurized by a pressurizing means is sprayed from a spray nozzle using a polishing machine provided between the spray pipe and an air inlet port through which air can be introduced into the spray pipe Then, the surface of the collided soil particles is polished and removed by colliding the soil particles flowing through the spray pipe with the deposition surface formed by the soil particles deposited in the particle deposition unit.

  In order to solve the above problems, a pollutant removal method according to the present invention includes a step of mixing and slurrying soil particles having a predetermined particle size or less containing pollutants and water, and a polishing machine having the above-described configuration. Supplying the slurry with pressure, using the polishing machine configured as described above, polishing and removing the surface of the soil particles, classifying the surface of the soil particles removed by the polishing machine as a contaminant, Have

  According to the polishing machine of the present invention, the pollutant removal system using the same, and the pollutant removal method, the fluid (slurry) containing the soil particles sprayed from the spray nozzle is transferred toward the front tube through the power tube. In the meantime, the soil particles collide and rub against each other, and the surface of the soil particles is polished to remove contaminants attached to the surface. In addition, soil particles contained in the slurry flowing from the spray pipe toward the front pipe collide with the inner wall of the front pipe. At that time, the soil particles are pressed and rubbed together, and the surface of the soil particles is polished to remove contaminants attached to the surface.

  Further, among the soil particles, particles having a relatively high density enter the particle accumulation portion and deposit on the particle accumulation portion to form a wall surface. Although the soil particles collide with the wall surface, an appropriate collision force can be applied to the soil particles to polish and remove the surface of the particles containing the contaminants without breaking the entire particle. And when colliding with the soil particle | grains of a particle deposition part, unlike making it collide with the wall surface of a grinder directly for a long time, there is no possibility of damaging a grinder.

  Further, when the pressure flow injected from the injection nozzle constituting the polishing machine spreads all over the injection pipe, the piston state moves at high speed, and a negative pressure is generated in the injection pipe upstream of the pressure flow. And by this negative pressure, air is naturally sucked into the injection pipe from the air inlet formed in the sludge volume reducing device, and the fluid containing the soil particles is pumped toward the downstream side of the injection pipe. Thereby, since the pressure difference between the upstream side and the downstream side of the injection nozzle is reduced, cavitation does not occur, and the impact force applied to the soil particles can be made much higher than when cavitation occurs. Further, since no cavitation occurs, no noise or vibration is generated from the polishing machine, and the polishing machine is not damaged, so that the service life can be extended as compared with the prior art.

  In addition, since the power tube is provided inside the spray tube of the polishing machine, the high-pressure fluid sprayed from the spray nozzle is guided along the power tube without diffusing in the spray tube to become a rod-like high-speed fluid. While maintaining a high speed, the gas flows downstream and collides with the wall surface of the particle deposition portion provided on the downstream side with high impact force. Thereby, it is possible to grind the surface of the soil particle contained in the particle with a high impact force.

  In addition, by having means for classifying fine particles separated from the surface of the soil particles polished and removed by the polishing machine as pollutants, reusable soil without pollutants, some containing pollutants Therefore, it becomes possible to divide into soil that needs to be further ground and soil that needs to be treated as a contaminant.

FIG. 1 is a schematic diagram showing the overall configuration of the contaminant removal system of the present invention. FIG. 2 is a schematic diagram showing a part of the pollutant removal system of the present invention. FIG. 3 is a schematic view showing details of the polishing machine constituting the contaminant removal system.

  Here, an embodiment of a polishing machine, a contaminant removal system using the polisher, and a contaminant removal method using the same according to the present invention will be described.

  The contaminants described here include radioactive substances such as radioactive cesium attached to the surface of the soil particles, as well as agricultural chemicals attached to the surface of the soil particles, but are not necessarily limited to these substances. .

FIG. 1 is a schematic diagram showing the overall configuration of a contaminant removal system according to the present invention. As shown in FIG. 1, a contaminant removal system 100 includes a plurality of polishing machines 1 (1a, 1b, 1c) and soil particles for removing contaminants adhering to the surface of soil particles by surface polishing. A plurality of mixing tanks 2 (2a, 2b, 2c) having a capacity of, for example, 70 m ³ , for generating water containing soil particles having a predetermined weight ratio (hereinafter “slurry”), A plurality of pressure pumps 3 (3a, 3b, 3c) with a pumping amount of 7 m ³ / min for pressurizing and feeding the slurry to the mixing tank 2, and a slurry to flow to the system 100 or to stop the flow of the slurry A plurality of valves M1, M2, M4, M5, M7, M8 and a plurality of valves M3, M6, M9 for supplying cleaning water to the system 100 or stopping the supply of cleaning water. Configured. The mixing tank 2a is provided with a vibrating sieve 4 for selecting the particle size of soil particles to be put into the mixing tank 2a to 2 mm or less. Each mixing tank 2a, 2b, 2c is provided with a water level sensor 6 for detecting the water level of the mixing tank. Between the valves M1 and M2 provided between the mixing tank 2a and the pressure pump 3a, a strainer 7 for filtering foreign substances contained in the slurry is provided. As the pressure pump 3, a known pressure pump can be used, and the slurry generated in the mixing tank 2 is sucked and pumped to the polishing machine 1 side.

  As shown in FIG. 1, the pollutant removal system 100 includes a mixing tank 2, a pressure pump 3, and a polishing machine 1, which are configured in three stages in series, and the slurry charged into the system 100. The same process is repeated three times. With such a configuration, the slurry can be simultaneously processed by the plurality of polishing machines 1, so that the processing amount per unit time can be increased. The slurry discharged from the polishing machine 1c provided in the lower stage is sent to a relay plant for temporarily storing or a classification plant 5 for classifying the polished soil particles.

  FIG. 2 shows a part of a set of apparatuses comprising the mixing tank 2, the pressure pump 3, and the polishing machine 1 in the contaminant removal system 100. The mixing tank 2 is provided with a stirrer 8. The stirrer 8 has a propeller portion 8a extending in the horizontal direction and a motor M coupled to the propeller portion 8a via a shaft 8b extending in the vertical direction from the propeller portion 8a. By driving the motor M, the propeller 8a rotates and stirs a predetermined amount of soil and water supplied into the mixing tank 2 to generate slurry. Moreover, a plate-like baffle plate 9 extending vertically is installed on the tank wall inside the mixing tank 2. By providing the baffle plate 9, the soil can be stirred in the vertical direction in the mixing tank 2, and the soil is more uniformly stirred. A front pipe 14, which will be described later, constituting the polishing machine 1 is connected to a rising pipe 10 that extends toward another mixing tank 2, and slurry flowing in the polishing machine 1 can be transferred to another mixing tank 2. It is.

  FIG. 3 is a diagram illustrating a configuration of the polishing machine 1. As shown in the figure, the polishing machine 1 includes a pressure gauge pipe 15 provided on the most upstream side (pressure pump 3 side) and provided with a pressure gauge (not shown), and an injection connected to the downstream side of the pressure gauge pipe 15. An injection nozzle 11 that is provided in the nozzle installation pipe 17 and injects the slurry pressurized by the pressure pump 3, is connected to the injection nozzle installation pipe 17 and is provided on the downstream side of the injection nozzle 11. A jet pipe 12 having a larger diameter and a front pipe 14 connected to the downstream side of the jet pipe 12 are provided. The inner diameter of the injection pipe 12 is almost the same from the upstream side to the downstream side.

The injection nozzle 11 is so thin that the inner diameter on the front end side (downstream side) is about 65 mm, and the slurry from the pressure pump 3 is further pressurized when passing through the injection nozzle 11, and is about 30 to about 45 m per second ( For example, the velocity at a pressure flow of 5 kg / cm ² is 31.30 m / sec, the velocity at a pressure flow of 6 kg / cm ² is 37.04 m / sec, the velocity at a pressure flow of 9 kg / cm ² is 42.00 m / sec, and the pressure flow is 10 kg. / Cm < ² >, it has the structure injected toward the injection pipe 12 at the injection speed of 44.27 m / sec. The above range is suitable as the injection speed to be injected into the injection pipe 12. The reason for this is that if the injection speed is lower than these speeds, the soil particles are less rubbed and the contaminants are removed. On the contrary, when the injection speed is higher than these speeds, it is necessary to enlarge the apparatus to withstand the impact force applied to the polishing machine 1, or the apparatus is easily broken by the impact force. In addition, a known pressure pump that injects sludge fluid with a pressure of 10 kg / cm ² or more is not a general-purpose pump, but an expensive special pressure pump that is difficult to use for general purposes. Not suitable.

  Inside the injection pipe 12, a tubular power tube 16 having an outer diameter smaller than the inner diameter of the injection pipe 12, an inner diameter of about 120 mm, and a length of about 600 to 800 mm is provided substantially concentrically with the injection pipe 12. The power tube 16 extends in the longitudinal direction through the inside of the injection tube 12 from the downstream side between injections to the upstream side. With such a configuration, the high-pressure jet flow of slurry injected from the injection nozzle 11 to the injection tube 12 is guided along the power tube 16 to become a rod-like high-speed fluid without being diffused, and the high speed is maintained. It flows into the front pipe 14 positioned in front of the injection pipe 12 as it is.

  The injection nozzle installation pipe 17 between the injection nozzle 11 and the injection pipe 12 is formed with an air introduction port 13 that allows the gap between the injection nozzle 11 and the injection nozzle installation pipe 17 to communicate with the outside of the polishing machine 1. ing. A plurality of the air inlets 13 are annularly arranged on the outer surface of the polishing machine 1 (injection nozzle installation pipe 17), and the outside air is configured to be taken into the injection pipe 12 from here.

  As described above, the slurry pumped by the pressure pump 3 is further pressurized by the jet nozzle 11 and jetted vigorously from the jet nozzle 11. When the jet flow from the injection nozzle 11 expands in the injection pipe, the piston moves at a high speed, and a vacuum state is generated on the upstream side of the injection pipe 12. Thus, air is naturally sucked into the injection pipe 12 from the air introduction port 13 by the negative pressure on the upstream side of the injection pipe 12. The jetted high-speed slurry entrains the sucked air, and the soil particles contained in the slurry are mixed, pressurized and stirred. In a state in which air is naturally sucked, the pressure distribution of the high-speed fluid from the upstream side to the downstream side of the injection nozzle is uniform and no portion to be depressurized is generated, so that cavitation does not occur. Therefore, the high-speed slurry is not decelerated, and the impact force when the soil particles collide with the inner wall of the front pipe 14 can be increased. Further, since cavitation does not occur, the polishing machine 1 is not easily broken, and the service life can be extended.

  When the jet stream ejected from the ejection nozzle 11 expands in the power tube 16, the soil particles are released from the pressure received during the ejection. As a result, a tensile force (which attempts to expand the particles) is applied to the soil particles, and the surface of the soil particles is peeled off by this force, and the contaminants attached to the surface are removed. Further, while the sprayed slurry is transported toward the front tube 14 in the power tube 16, the soil particles collide and rub against each other, and the soil particles are polished so that the contaminants adhered to the surface. Is removed.

  The front pipe 14 located in front of the injection pipe 12 is a cross joint with a flange, the mouth on the side of the injection pipe 12 communicates with the injection pipe 12, and the mouth opposite to the injection pipe 12 is closed by a flange lid. It has been. One of the two ports of the front pipe 14 opened in a direction orthogonal to the longitudinal direction of the injection pipe 12 communicates with the mixing tank 2 or the classification plant 5 through the outlet 18 and the other. Is closed by a flange lid.

  Soil particles contained in the slurry flowing from the spray pipe 12 toward the front pipe 14 collide with the inner wall of the front pipe 14. A large collision force is generated in the soil particles having a specific gravity larger than the moisture contained in the slurry, and the soil particles are strongly pressed against the inner wall of the front pipe 14. At that time, the soil particles are pressed and rubbed together, and the surface of the soil particles is polished to remove contaminants attached to the surface.

  When soil particles collide with the inner wall of the front pipe 14, if the inner wall is too hard, the collision force acting on the particles is too large, so that only the surface of the particles containing contaminants is not removed, and the entire particle May break. In this case, the surface layer part of the particle containing the contaminant and the central part of the particle not containing the contaminant are divided in an integrated form and sent to the mixing tank as it is to remove the contaminant. I can't. On the other hand, if the inner wall of the front tube 14 is too soft, the impinging force sufficient to polish the surface of the soil particles and remove contaminants from the surface cannot be applied to the soil particles. Therefore, in order to apply an appropriate collision force to the soil particles, the present invention uses the front pipe 14 that is a cross joint as follows.

  When the soil particles contained in the slurry flow into the front pipe 14 from the injection pipe 12, particles having a relatively high density among the soil particles do not flow out from the outlet 18 toward the mixing tank 2 or the classification plant 5, Only the particles having a relatively low density flow out of the front tube 14 after entering the particle accumulation portion 19 formed so as to be recessed in the front tube 14. The particles having a relatively high density are deposited as a particle layer 20 in the particle deposition portion 19 that is recessed with time. Then, a wall surface of the particle layer 20 made of particles having a relatively high density as shown by the wall surface W is formed in the front tube 14. The soil particles that have flowed into the front pipe 14 from the spray pipe 12 collide with the wall surface W, but the wall surface W has an appropriate collision force for polishing and removing the surface of particles containing contaminants without breaking the entire particle. Can act on the soil particles. Further, when the soil particles directly collide with the inner wall of the front tube 14, there is a possibility that a hole may open in the inner wall of the front tube 14 with the passage of time due to the collision force. However, in the present invention, since the inner wall of the front tube 14 is protected by the particle layer 20 deposited in the particle accumulation portion 19, it is possible to prevent the inner wall of the front tube 14 from being damaged. If the flange lid of the front tube 14 is opened, the particle layer 20 deposited in the particle accumulation unit 19 can be appropriately taken out of the front tube 14.

Here, with reference to FIG. 1, a series of flows of contaminant removal by the contaminant removal system 100 will be described. First, the soil containing pollutants is scraped off by a depth of 5 cm from the soil surface. The shaved soil is put on the vibrating sieve 4 and a particle having a particle size of 2 mm or less is selected. Soil particles having a particle size of 2 mm or less are supplied to the mixing tank 2a, and water is introduced into the mixing tank 2a. By stirring with the stirrer 8, the soil particles and water are mixed and a slurry is generated. A slurry having a water: soil weight ratio of 4: 1 is generated in the mixing tank 2a (when a 70 m ³ mixing tank is filled with the slurry, 14 t of soil is put in the mixing tank).

  Next, the slurry containing soil particles is pressurized and supplied into the polishing machine 1a using the pressure pump 3a. The surface of the soil particles is polished by the polishing machine 1a to remove contaminants. The slurry containing the soil particles polished by the polishing machine 1a is sent into the mixing tank 1b. The slurry is pressurized and supplied into the polishing machine 1b using the pressure pump 3b. The surface of the soil particles is further polished by the polishing machine 1b to remove contaminants. The slurry containing the soil particles polished by the polishing machine 1b is sent into the mixing tank 2c. The slurry is pressurized and supplied into the polishing machine 1c using the pressure pump 3c. The surface of the soil particles is further polished by the polishing machine 1c to remove contaminants. The slurry containing the soil particles polished by the polishing machine 1b is sent to the relay plant or the classification plant 5. When the contaminant removal system 100 is stopped, an operation for opening the valves M3, M6, and M9 is performed. As a result, clean water is supplied to the pressure pump 3 and the polishing machine 1, and the soil particles remaining in the pressure pump 3 and the polishing machine 1 are washed away, so that the piping in the pressure pump 3 and the polishing machine 1 is made of soil particles. It is possible to prevent the blockage.

  In the classification plant 5, the particles are classified into several types according to the particle size of the soil particles contained in the slurry. Of these, particles with a relatively small particle size are considered to consist of parts removed by surface polishing with a polishing machine. Keep until final processing. In addition, soil particles having other particle sizes can be used as reusable soil, and some of the contaminants remain on the surface of the particles and are introduced into the contaminant removal system 100 again. The removal process is further divided into those for further implementation.

Using the contaminant removal system 100 as described above, it is possible to process a slurry of 7 m ³ per minute. In this case, the mixing tank 2a is continuously supplied with soil having a particle diameter of 2 mm or less at 1.4 t / min and water at 5.6 m ^{3 /} min. This means that 84 tons of soil per hour can be processed by the system 100, and the processing capability is superior to the case of polishing soil particles by using a ball mill. In addition, the processing amount per hour of soil can be changed by changing the pumping amount of the pressure pump 3 or the diameter of the injection nozzle 11.

1 Polishing machine 2 Mixing tank 3 Pressure pump (pressurizing means)
4 Vibrating sieve 5 Classification plant (Means for classification)
8 Stirrer 11 Injection nozzle 12 Injection pipe 13 Air inlet 14 Front pipe 16 Power tube 17 Injection nozzle installation pipe 18 Outlet 19 Particle accumulation part 20 Particle layer 100 Contaminant removal system W Wall surface

Claims (7)

An injection nozzle for injecting a fluid obtained by mixing the soil particles pressurized by the pressurizing means and water into a slurry, an injection pipe provided on the downstream side of the injection nozzle and having a larger diameter than the injection nozzle, and It provided downstream of the injection pipe, disposed between the particle deposition portion relatively dense particles recessed possible deposition of the soil particles contained in the fluid, and the injection nozzle and the injection pipe An air inlet capable of introducing air into the injection pipe;
Soil particles flowing through the injection pipe, collides with the wall surface formed by a relatively dense soil particles deposited on the particle deposition portion, thereby, the surface of the collision soil particles is removed by polishing, among soil particles the relatively low density of particles, polishing machine, characterized that you flowing out without depositing on the particle deposition portion. Inside the injection pipe, a tubular power tube having an outer diameter smaller than the inner diameter of the injection pipe and an inner diameter larger than the injection nozzle is provided substantially concentrically with the injection pipe,
The polishing machine according to claim 1, wherein the power tube extends in a longitudinal direction of the spray tube so that soil particles contained in a fluid can collide with the wall surface.   The polishing machine according to claim 1 or 2, wherein the spray pressure of the fluid containing soil particles sprayed from the spray nozzle is a pressure of 0.5 to 1.0 MPa. The polishing machine according to any one of claims 1 to 3,
A mixing tank for mixing and slurrying soil particles having a predetermined particle size or less with contaminants adhering to the surface, and a fluid;
Pressurizing means for pressurizing and supplying slurry from the mixing tank to the polishing machine;
Means for classifying the surface of the soil particles polished and removed by the polishing machine as a contaminant;
Contaminant removal system characterized by comprising:   The pollutant removal system according to claim 4, wherein the pollutant is radioactive cesium. A method for polishing soil particles,
An injection nozzle for injecting a fluid obtained by mixing the soil particles pressurized by the pressurizing means and water into a slurry, an injection pipe provided on the downstream side of the injection nozzle and having a larger diameter than the injection nozzle, and It provided downstream of the injection pipe, disposed between the particle deposition portion relatively dense particles recessed possible deposition of the soil particles contained in the fluid, and the injection nozzle and the injection pipe Using a polishing machine comprising an air inlet capable of introducing air into the jet pipe,
Soil flowing through the spray pipe on a deposition surface formed by relatively high density soil particles deposited in the particle deposition section by spraying fluid containing soil particles pressurized by the pressurizing means from the spray nozzle. By colliding the particles, the surface of the collided soil particles is removed by polishing , and particles having a relatively low density among the soil particles flow out of the polishing machine without being deposited in the particle accumulation unit. Feature method. A contaminant removal method comprising:
Mixing and slurrying soil particles having a predetermined particle size or less with contaminants attached to the surface and water;
Pressurizing and supplying the slurry to the polishing machine according to claim 6;
Polishing and removing the surface of the soil particles using the polishing machine according to claim 6;
Classifying the surface of the soil particles polished and removed by the polishing machine as a contaminant;
A method characterized by comprising: