Slurry cleaning apparatus

Abstract

To provide an apparatus capable of efficiently cleaning slurry containing fine particles in a slurry cleaning apparatus that removes dissolved components in slurry by making cleaning water pass through the slurry at the front stage of a dewatering machine.SOLUTION: A slurry cleaning apparatus for removing dissolved components in slurry by supplying cleaning water to the slurry at the front stage of a dewatering machine includes: a washing cylinder having screw blades that revolve around a revolving shaft, inclines downward in the radial direction of the revolving shaft and conveys upward by rotation; a jacket connected to the washing cylinder with a specified gap and surrounding the lower portion of the washing cylinder; a slurry pipe supplying the slurry to the lower portion of the washing cylinder; a cleaning water pipe supplying cleaning water to the upper portion of the washing cylinder; an upper receiving tray collecting the washed slurry discharged from the upper part of the washing cylinder; and a lower receiving tray collecting the washed wastewater discharged from the jacket. Thus, slurry containing fine particles can be efficiently washed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a slurry washing device that washes a slurry in the upstream stage of a dehydrator. [Background technology]

[0002] Conventionally, when a dehydrated cake with reduced dissolved components in the slurry is required in a dehydration process for dehydrating the slurry, there is a technique for lowering the concentration of dissolved components in the slurry by supplying wash water to the slurry. Methods for washing the slurry include dilution washing, in which wash water is supplied to the slurry in the upstream stage of the dehydrator, and cake washing, in which wash water is supplied to the dehydrated cake produced in the dehydrator.

[0003] Patent Document 1 also discloses a dissolving device in which nuclear fuel fed from a dissolving tank is dissolved in a nitric acid solution supplied from above an inclined discharge pipe connected to the dissolving tank and discharged as a fuel dissolving liquid, and in which insoluble matter that settles in the dissolving tank is transported upwards by a swirling blade that can be rotated in the discharge pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-007534 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the solids in slurries have tended to become finer, but because fine particles have a slow settling velocity, there is a risk that the solids will flow out of the washing device together with the washing water, or that the washing water mixed with the solids will remain in the washing device. For this reason, it has taken a long time to wash slurries containing fine particles. Dilution washing, in which washing water is supplied to the slurry in the upstream stage of the dehydrator, requires repeated supply of washing water to dilute the slurry to the desired concentration, and the slurry needs to be concentrated between washings, which makes washing time-consuming and requires a large amount of washing water. Also, cake washing, in which washing water is supplied to the dehydrated cake generated by the dehydrator, requires a long time for washing and causes uneven washing of the dehydrated cake because the washing water is not easily distributed throughout the cake.

[0006] The device according to Patent Document 1 contacts the insoluble matter transported upward by the swirling blades with the nitric acid solution in a countercurrent multi-stage manner from above, and the bottom of the inclined surface of the discharge pipe is connected to the bottom of the dissolution tank, making it possible to easily transport the insoluble matter that has settled to the bottom of the dissolution tank. However, if the object to be transported is a slurry containing fine particles and washing water is supplied from above, it takes a very long time for the fine particles to settle in the tank in natural settling, so the particles and liquid overflow to the lower stage while remaining in suspension, and the solid matter in the slurry flows out together with the washing water. Furthermore, there are problems such as the need to insert a concentration process before the dehydration process and the increase in the amount of flocculant added when a flocculant is added before the dehydration process because washing water remains in the slurry after washing.

[0007] The present invention relates to a slurry washing apparatus that removes dissolved components in a slurry by passing wash water through the slurry in the upstream stage of a dehydrator, and provides an apparatus capable of efficiently washing a slurry that contains fine particles with a slow settling velocity in particular. [Means for solving the problem]

[0008] In a slurry washing device that supplies washing water to a slurry in a front stage of a dehydrator to remove dissolved components in the slurry, the device has a washing tube that revolves around an axis of revolution, tilts downward in the radial direction of the axis of revolution, and has a screw blade that transports upward by rotating, a jacket that is connected to the washing tube with a specified gap and surrounds the lower part of the washing tube, a slurry pipe that supplies slurry to the lower part of the washing tube, a washing water pipe that supplies washing water to the upper part of the washing tube, and an upper tray that collects the washed slurry discharged from the upper part of the washing tube and a lower tray that collects the washing wastewater discharged from the jacket, which are arranged in an annular shape around the orbit of the washing tube, generate centrifugal force in the washing tube to press the slurry particles against the side wall in the washing tube, and do not overflow to the lower stage together with the washing water. This allows the slurry to be washed efficiently.

[0009] By having a supply tube above the cleaning tube that can rotate together with the revolution axis and stores slurry and cleaning water, a slurry pipe that communicates with the bottom of the supply tube and extends to the bottom inside the cleaning tube, and a cleaning water pipe that extends to the top inside the cleaning tube, the slurry that has been stirred in the supply tube and has stable properties can be transferred to the cleaning tube.

[0010] By having a cylindrical casing outside the orbit of the cleaning tube, a revolution shaft connected to the revolution drive, and a rotating frame extending from the revolution shaft in the radial direction of the casing and supporting the cleaning tube, the solid content of the slurry does not overflow to the lower level, even in the case of a slurry containing fine particles with a slow settling rate, so that the solid content concentration of the slurry after cleaning does not decrease. Effect of the Invention

[0011] According to the present invention, the slurry is stirred in the supply tube, so that the slurry with stable properties can be transferred to the washing tube. In addition, the slurry can be washed in a countercurrent multi-stage manner by passing washing water from above into the slurry transported upward by the screw blade in the washing tube, so that the slurry can be washed efficiently. Furthermore, the slurry particles are pressed against the wall surface of the washing tube by the centrifugal force acting in the washing tube, and the slurry particles can be prevented from overflowing to the bottom of the washing tube together with the washing water, so that the washed slurry can be collected without reducing the solid content concentration. And, even fine particles with a slow settling speed are quickly pressed against the wall surface of the washing tube by the centrifugal force, so that the washing tube can be rotated and washing can be started without waiting for natural settling, and the processing speed is improved. [Brief description of the drawings]

[0012] [Figure 1] 1 is a vertical sectional view of a slurry washing device according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of a supply tube of the slurry washing device. [Diagram 3] FIG. 2 is a cross-sectional view of a cleaning tube of the slurry cleaning device. [Figure 4] FIG. [Diagram 5] FIG. 11 is a cross-sectional view of a supply tube according to another embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view of a cleaning tube according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] FIG. 1 is a vertical sectional view of a slurry washing device according to the present invention. The slurry washing apparatus 1 of the present invention is composed of a cylindrical casing 2, an orbital shaft 3 connected to an orbital drive 5, a supply tube 8 that temporarily stores slurry and washing water and supplies them to the washing tube 12, and the washing tube 12 that revolves within the casing 2 by the rotation of the orbital shaft 3 and is rotatably connected by the rotation drive 6.

[0014] The revolution shaft 3 is provided on the central axis of the cylindrical casing 2 via the revolution drive 5 fixed near the bottom of the casing 2. A supply tube 8 for slurry and cleaning water is connected to the revolution shaft 3 and rotates together with the revolution shaft 3. In addition, a rotating frame 17 extending in the radial direction of the casing 2 is provided on the revolution shaft 3, and the autorotation drive 6 and cleaning tube 12 provided on the rotating frame 17 rotate inside the casing 2 in synchronization with the revolution shaft 3.

[0015] FIG. 2 is a cross-sectional view of a supply tube of the slurry washing apparatus according to the present invention. Supply tube 8 is divided into two chambers, upper and lower, and stores slurry and wash water separately. Slurry is supplied from a pump (not shown) to slurry supply pipe 7 fixed to casing 2, and sent to slurry chamber 20, the upper chamber. Wash water is supplied from another pump (not shown) to wash water supply pipe 9 inserted inside slurry supply pipe 7, and sent to wash water chamber 21, the lower chamber.

[0016] The slurry supply pipe 7 and the cleaning water supply pipe 9 are not in contact with the supply cylinder 8, and do not rotate with the revolution shaft 3. A known water-stopping structure is provided near the cleaning water supply pipe 9 on the bottom surface of the slurry chamber 20 to prevent the slurry from mixing into the cleaning water chamber 21. Although the cleaning water supply pipe 9 and the slurry supply pipe 7 are double pipes, the embodiment is not limited, and separate piping may be provided.

[0017] By the rotation of the supply tube 8 which rotates integrally with the revolution shaft 3, centrifugal force acts inside the supply tube 8, stirring the slurry in the slurry chamber 20. As a result, even when the slurry washing device 1 is operated continuously, the properties of the slurry temporarily stored in the slurry chamber 20 can always be stabilized.

[0018] A slurry pipe 10 and a washing water pipe 11 are connected to the bottom of the slurry chamber 20 and the washing water chamber 21, respectively, and extend from the supply tube 8 in the radial direction of the casing 2 and at an incline downward. The lower parts of the slurry pipe 10 and the washing water pipe 11 extend to the washing tube 12, which will be described later, and supply the slurry and washing water into the washing tube 12.

[0019] In addition, when the stirring process in the supply tube 8 is not necessary due to the slurry properties or the presence or absence of a slurry stirring equipment in the upstream stage, a configuration in which the slurry and washing water can be directly supplied to the washing tube 12 from inside the revolution shaft 3 can be used instead of the supply tube 8. In addition, appropriate modifications can be made, such as making the slurry chamber 20 of the supply tube 8 the lower chamber and the washing water chamber 21 the upper chamber.

[0020] FIG. 3 is a cross-sectional view of the cleaning tube of the slurry cleaning device according to the present invention. The washing tube 12 is disposed at an angle downward in the radial direction of the casing 2 so as to be parallel to the flow paths of the slurry pipe 10 and the washing water pipe 11. The lower end of the washing tube 12 is open, and the lower part is surrounded by a cylindrical jacket 13. The jacket 13 is connected to the washing tube 12 by ribs or the like, and has a washing drainage discharge hole 25 opening in the upper surface.

[0021] A rotation shaft 4 is fixed to the bottom surface of the jacket 13, and the cleaning tube 12 and the jacket 13 are configured to be rotatable by operating a rotation shaft driver 6 connected to the lower part of the rotation shaft 4.

[0022] The rotating shaft 4 is supported via bearings 22 on the rotating frame 17 shown in Figs. 1 and 3. This allows the rotating shaft 4 to perform planetary motion around the revolution axis 3. In this embodiment, two cleaning tubes 12 are provided inside the casing 2, but the number of cleaning tubes 12 installed and their individual installation positions are not limited. When changing the number of cleaning tubes 12 installed, the number of branches of the slurry pipes 10 and cleaning water pipes 11 and the rotating frame 17 are changed. In addition, the rotating shaft driver 6 may be fixed to the rotating frame 7.

[0023] A spiral screw blade 23 is fixed to the inner wall of the washing tube 12. The screw blade 23 is shaftless and open near the center, so that the slurry pipe 10 and the washing water pipe 11 extended from the supply tube 8 can be inserted into the inside of the washing tube 12. The lower end of the slurry pipe 10 extends to the bottom of the washing tube 12, and the slurry transferred from the supply tube 8 is supplied to the bottom of the washing tube 12. The lower end of the washing water pipe 11 extends to the top of the washing tube 12, and the washing water transferred from the supply tube 8 is supplied to the top of the washing tube 12. The extended positions of the slurry pipe 10 and the washing water pipe 11 are appropriately set according to the conditions.

[0024] By driving the rotation driver 6, the cleaning tube 12 and the jacket 13 are rotated integrally. In addition, since the screw blade 23 is fixed to the cleaning tube 12, the screw blade 23 also rotates together with the cleaning tube 12. When the slurry washing device 1 is in operation, the revolution driver 5 is driven at the same time, and the centrifugal force caused by the rotation of the revolution shaft 3 is transmitted to the cleaning tube 12 via the rotating frame 17.

[0025] FIG. 4 is an enlarged cross-sectional view of the cleaning tube 12. As shown in FIG. 4, the slurry supplied from the slurry pipe 10 to the lower part of the cleaning tube 12 is pressed against the inner wall of the cleaning tube 12 toward the side wall of the casing 2 by the centrifugal force generated by the rotation of the revolution shaft 3. The slurry particles, which are the solid content of the slurry, are transported to the screw blade 23 by the rotation of the rotation shaft 4 and rise inside the cleaning tube 12. At this time, the slurry particles are held in the space formed by the inner wall of the cleaning tube 12 on the casing 2 side and the screw blade 23. A moisture layer is formed on the surface of the slurry layer where the slurry particles are separated from the slurry. In this way, the slurry can be instantly separated into slurry particles and moisture by using the centrifugal force generated by the rotation of the revolution shaft 3 and the rotation shaft 4.

[0026] The washing water supplied from the washing water pipe 11 to the upper part of the washing tube 12 flows into the moisture layer held on the surface of the slurry layer. As the washing water flows in, the volume of the moisture layer becomes equal to or larger than the space formed by the side wall of the washing tube 12 and the screw blade 23, and the overflowing moisture overflows to the lower level through the hollow part of the screw blade 23. At this time, the slurry particles are sufficiently pressed against the wall surface by centrifugal force, so the slurry layer does not collapse due to the inflow of the washing water. Therefore, since only the moisture in the slurry can be made to overflow to the lower level, it is possible to reduce only the concentration of dissolved components without reducing the concentration of solids in the slurry.

[0027] In addition, the overflowing moisture flows through the space near the center of the screw blade 23 into the lower space, and the cleaning water flowing into the lower space moves toward the side wall of the cleaning tube 12 due to centrifugal force, so that it can efficiently come into contact with the moisture layer in the lower space.

[0028] The slurry transported to the top of the washing tube 12 is discharged from the slurry discharge hole 24 provided at the top of the washing tube 12. At this time, the slurry is subjected to centrifugal force due to the rotation of the revolution shaft 3, so that the slurry is always discharged vigorously from the slurry discharge hole 24 located on the casing 2 side. In addition, the upper receiver 14 that receives the slurry discharged from the slurry discharge hole 24 is provided in an annular shape on the inner wall of the casing 2, so that the discharged slurry can be reliably collected in its entirety. Above the upper receiver 14, a slurry reflector 30 is provided in an annular shape on the inner wall of the casing 2, which prevents the slurry that has jumped out of the slurry discharge hole 24 from scattering and causes it to fall into the upper receiver 14. The upper receiver 14 is connected to a slurry discharge pipe 26 provided on the side of the casing 2, so that the slurry collected in the upper receiver 14 can be discharged outside the device through the slurry discharge pipe 26.

[0029] The position of the slurry discharge hole 24 is not particularly limited as long as the present embodiment of the cleaning tube 12 can be sufficiently implemented. In addition, the slurry discharge hole 24 may be provided with a plurality of holes of a specific size, or, for example, the entire area in which the holes are provided may be a single opening.

[0030] The washing water that has overflowed to the bottom end of the washing tube 12 and the water content in the slurry are accumulated in the jacket 13 as washing wastewater. After the washing wastewater mixes with the slurry accumulated in the lower part of the jacket 13, the slurry particles are pressed against the bottom wall surface of the jacket 13 by the action of centrifugal force, and only the washing wastewater floats to the top of the jacket 13. When the floating washing wastewater exceeds a certain amount, it is discharged from the washing wastewater discharge hole 25 provided in the upper part of the jacket 13. Then, the washing wastewater is forcefully discharged toward the casing 2 side by the action of the centrifugal force of the revolution shaft 3. At this time, the slurry that has accumulated on the bottom wall surface of the jacket 13 is transported upward by the screw blades 23 when it reaches a certain amount or more, so it is not piled up to a height higher than the position shown in FIG. 4.

[0031] The lower tray 16 that receives the washing wastewater discharged from the washing wastewater discharge hole 25 is provided in an annular shape on the inner wall of the casing 2, so that the entire amount of the discharged washing wastewater can be collected. The upper tray 14 arranged above the lower tray 16 prevents the washing wastewater that has jumped out of the washing wastewater discharge hole 25 from scattering and causes it to fall into the lower tray 16. Note that a separate member, similar to the slurry reflector 30, may be provided on the inner wall of the casing 2 to prevent the washing wastewater from scattering. The lower tray 16 is connected to a washing wastewater discharge pipe 27 provided on the side of the casing 2, so that the washing wastewater collected in the lower tray 16 can be discharged from the washing wastewater discharge pipe 27 to the outside of the apparatus.

[0032] Also, a washing drainage discharge hole 25 may be provided in the bottom surface of the jacket 13 within a range smaller than the diameter of the hollow part of the screw blade 23. Since a slurry layer and a water layer are also formed at the bottom of the jacket 13 by centrifugal force, the washing drainage accumulated at the bottom of the jacket 13 can be discharged from the washing drainage discharge hole 25 so as to overflow from the hollow part of the screw blade 23. In this case, a member capable of collecting the washing drainage discharged from the washing drainage discharge hole 25 and discharging it into the lower receiver 16 may be added. Note that the slurry is pressed against the wall surface of the washing tube 12, so it does not flow out from the washing drainage discharge hole 25.

[0033] When cleaning the inside of the device 1, cleaning water can be drained by providing a drain pipe at the bottom of the casing 2. In that case, a drain path to the drain pipe may be formed in a sloped shape throughout the entire lower part of the inside of the casing 2, or a known seal structure may be provided for the drivers 5, 6, etc.

[0034] The lower end positions of the slurry pipe 10 and the washing water pipe 11 may be appropriately set depending on the conditions, but the lower end of the slurry pipe 10 is preferably located at a position where the supplied slurry rests on the lowest screw blade 23 .

[0035] In addition, with regard to the position of the lower end of the cleaning water pipe 11, if the position of the lower end of the cleaning water pipe 11 is set at the upper part of the cleaning tube 12, the number of spaces in which the slurry transported to the upper part of the cleaning tube 12 comes into countercurrent contact with the cleaning water increases, thereby improving the effect of countercurrent multi-stage cleaning. If the lower end position of the washing water pipe 11 is set to a certain degree below the top of the washing tube 12, the washing water will not come into contact with the slurry transported to the top of the washing tube 12. Therefore, by expanding the diameter of the hollow part near the center of the shaftless screw blade 23 only at the upper stage, only the water accumulated on the surface of the slurry layer can be made to overflow to the lower stage. This can enhance the slurry concentration effect.

[0036] FIG. 5 is a cross-sectional view of a supply tube according to another embodiment of the present invention. The supply tube 8 shown in Fig. 5 is characterized by the fact that a screen 28 is installed to divide the inside of the slurry chamber 20 into two chambers, an upper one and an lower one. The slurry supplied to the slurry chamber 20 from the slurry supply pipe 7 is pressed against the wall of the supply tube 8 while being stirred by the centrifugal force caused by the rotation of the revolution shaft 3. At this time, the filtrate is separated from the slurry by gravity separation, and only the filtrate falls from the screen 28 at the bottom.

[0037] The filtrate that has passed through the screen 28 is discharged outside the machine through the filtrate discharge passage 29. The slurry pressed against the wall surface of the supply tube 8 is successively discharged through the slurry pipe 10 provided on the side wall of the supply tube 8 and sent to the next stage washing tube 12. The washing water is sent to the washing water chamber 21 through the washing water supply pipe 9 and stored therein, and then successively discharged through the washing water pipe 11 and sent to the washing tube 12.

[0038] In this embodiment, the slurry is concentrated in the supply tube 8, so that the contact rate with the slurry particles is increased when cleaning water is passed through the subsequent cleaning tube 12. This can improve the cleaning effect of the slurry.

[0039] In addition, in order to prevent clogging of the screen 28, a known means such as a scraper may be incorporated in the supply tube 8, and the supply tube 8 may be made disassembled into the top and bottom to facilitate cleaning of the screen 28.

[0040] FIG. 6 is a cross-sectional view of a cleaning tube according to another embodiment of the present invention. The cleaning tube 12 shown in Fig. 6 is characterized in that the lower end of the screw blade 23 is supported by the rotating shaft 4. By driving the rotating shaft driver 6, the screw blade 23 inside the cleaning tube 12 rotates. The cleaning tube 12 and the jacket 13 are directly fixed to the rotating frame 17, and the cleaning tube 12 does not rotate even if the rotating shaft driver 6 is driven. It rotates inside the casing 2 only by the rotation of the revolution shaft 3, without changing its orientation relative to the revolution shaft 3.

[0041] Since the cleaning tube 12 does not rotate with the rotation shaft 4, the slurry discharge hole 24 is only open in a portion on the casing 2 side, and the slurry transported to the top of the cleaning tube 12 by the rotation of the screw blades 23 is discharged into the upper receiving tray 14. When a certain amount of washing wastewater is accumulated in the jacket 13, it is discharged from the washing wastewater discharge hole 25. Like the slurry discharge hole 24, the washing wastewater discharge hole 25 is also open only partially on the casing 2 side, and discharges the washing wastewater from the lower receiver 16.

[0042] In this embodiment, since the cleaning tube 12 does not rotate together with the rotation shaft 4, the slurry pipe 10 and the cleaning water pipe 11 may be connected to the side surface of the cleaning tube 12.

[0043] In this embodiment, all the screw blades 23 are shaftless, but screw blades with shafts may be used. In that case, the screw shaft may be fixed to the washing tube 12 to rotate the screw blades and the washing tube 12 together, or the screw shaft may be connected to the rotating shaft 4 to rotate only the screw blades. Also, the slurry pipe 10 and the washing water pipe 11 may be inserted into the screw shaft, and supply holes for supplying the slurry and washing water from the shaft center may be opened on the screw shaft, respectively. [Industrial Applicability]

[0044] The slurry washing device of the present invention performs countercurrent multi-stage washing in a washing tube that moves in planetary motion, and can wash the slurry efficiently. Therefore, it is suitable for installation in the front stage of a solid-liquid separator used in a production process that contains a large amount of organic slurry or for industrial wastewater, and is particularly suitable for washing slurries that contain fine particles with slow settling speeds. [Explanation of symbols]

[0045] 1 Slurry cleaning equipment 2 Casing 3. Orbital axis 5. Revolution drive mechanism 8 Supply tube 10 Slurry pipe 11 Cleaning water pipe 12 Cleaning tube 13. Jacket 14 Upper tray 16 Lower tray 17 Rotating Frame 23 Screw blade

Claims

1. A slurry washing apparatus (1) for removing dissolved components in a slurry by supplying washing water to the slurry in a stage preceding a dehydrator, a cleaning tube (12) having a screw blade (23) that revolves around an orbital axis (3), is inclined downward in the radial direction of the orbital axis (3), and conveys upward by rotating; a jacket (13) that is connected to the cleaning tube (12) with a predetermined gap therebetween and surrounds the lower part of the cleaning tube (12); a slurry pipe (10) for supplying slurry below the cleaning tube (12); A cleaning water pipe (11) for supplying cleaning water to an upper portion of the cleaning tube (12); The washing apparatus has an upper tray (14) for collecting the washed slurry discharged from the upper part of the washing tube (12) and a lower tray (16) for collecting the washing wastewater discharged from the jacket (13), which are arranged in an annular shape around the revolution orbit of the washing tube (12). A slurry washing device characterized by:

2. A supply tube (8) that is rotatable together with the revolution shaft (3) above the cleaning tube (12) and that stores slurry and cleaning water, respectively; The supply tube (8) has a slurry pipe (10) that is connected to the bottom surface of the supply tube (8) and extends into the washing tube (12), and a washing water pipe (11).

2. The slurry washing apparatus according to claim 1, wherein the slurry washing apparatus comprises:

3. A cylindrical casing (2) outside the orbit of the cleaning tube (12), a rotary frame (17) extending from the revolution axis (3) in the radial direction of the casing (2) and supporting the cleaning tube (12) so that the cleaning tube (12) can rotate freely; 3. The slurry washing device according to claim 2, wherein the slurry washing device comprises:

Images