JP6513460B2 - Separation filtration system and separation filtration method - Google Patents

Description

  The present invention relates to a separation and filtration system and a separation and filtration method for separating and filtering target particles in a liquid to be processed to produce a clear liquid.

  In the past, a separation filtration system has been widely adopted, in which a capture substance that captures harmful substances is added to sewage containing harmful substances, polluted water, etc., and then the capture substance that captures harmful substances is removed from the liquid to generate clear fluid. It is done. For example, in the separation and filtration system shown in Patent Document 1, a separation process of subjecting a liquid to be treated in which Prussian blue nanoparticles (capture substance) are charged to contaminated water in which radioactive cesium is dissolved is centrifuged; And filtering the separated liquid separated from the concentrate with a filter.

  In such separation and filtration steps, although the concentrate containing Prussian blue nanoparticles having captured cesium ions is removed from the solution, the concentration of Prussian blue nanoparticles is large, so the concentrate is repeated in the liquid to be treated. By using it, Prussian blue nanoparticles are effectively used.

JP, 2014-109461, A

  As in the separation filtration system shown in the above-mentioned Patent Document 1, when the concentrate is repeatedly fed, the clear liquid can not be obtained although there is still room to capture the cesium ion even if the Prussian blue nanoparticles still capture cesium ions. Alternatively, there is a problem that the filtration efficiency is lowered, for example, it takes a long time to obtain a clear solution.

  Then, this invention aims at providing the separation filtration system and the separation filtration method which can improve filtration efficiency.

In order to solve the above problems, in the separation and filtration system of the present invention, a concentrate is separated in a solid-liquid separation unit that separates a liquid to be treated containing a target substance into a concentrate and a separation liquid, and a solid-liquid separation unit And a separated liquid storage part provided between the solid-liquid separation part and the filtration part and storing the separated liquid generated in the solid-liquid separation part, and stored in the separated liquid storage part A particle size adjustment unit that performs particle size adjustment processing to reduce the particle size of the target substance with respect to the separated liquid, an inflow amount of the separated liquid flowing from the solid-liquid separation unit into the separated liquid storage unit, and And a control unit that performs drive control of the particle size adjustment unit in accordance with one or both of the outflow amounts of the separated liquid flowing out to the filtration unit .

  The particle size adjusting unit may reduce the particle size by crushing the target substance in the particle size adjusting process.

  In addition, the target substance is a dispersion containing nanoparticles, and the nanoparticles may be separated and filtered.

  Also, the nanoparticles may be Prussian blue nanoparticles.

  Further, the liquid processing apparatus further comprises a liquid processing tank for storing a liquid to be treated in which Prussian blue nanoparticles are added to a stock solution in which cesium ions are dissolved, and the liquid tank has at least one of a solid-liquid separation unit and a filtration unit. The removed concentrate containing the cesium ion-captured Prussian blue nanoparticles may be reintroduced.

  In addition, the particle size adjustment unit may return the separated liquid after the particle size adjustment processing to the separated liquid storage unit.

  In addition, the control unit may stop the driving of the particle size adjustment unit when the inflow amount or the outflow amount of the separation liquid becomes equal to or less than a preset threshold value.

  In addition, the solid-liquid separation unit preferably includes a centrifugal separator that applies centrifugal force to the liquid to be treated to separate the concentrate and the separated liquid.

In order to solve the above problems, the separation and filtration method of the present invention comprises the steps of separating a liquid to be treated containing a target substance into a concentrate and a separation liquid, and storing the separation liquid in a separation liquid reservoir. generating a clear separation was filtered solution, and performing particle size control process to reduce the particle size of the substance with respect to the separation liquid stored in the separated liquid reservoir, and flows into the separated liquid reservoir And d) performing drive control of the particle size adjustment processing according to one or both of the inflow of the separated liquid and the outflow of the separated liquid flowing out of the separated liquid storage portion .

  According to the present invention, the filtration efficiency can be improved.

It is a figure showing composition of a separation filtration system of this embodiment. It is a figure which shows the specific structural example of a separation filtration system. FIG. 1 is a perspective view showing a schematic configuration example of a screw decanter type centrifuge. It is the longitudinal cross-sectional view which showed the schematic structural example of the screw decanter type | mold centrifuge. It is a figure explaining the effect | action of a screw decanter type | mold centrifuge. It is the perspective view which showed the structural example of the filtration apparatus. It is the schematic of the vertical cross section in the VII-VII line of FIG. It is a figure explaining an example of the particle size distribution of the deposit thing formation layer formed in a filter. It is a figure explaining the example of particle size distribution of the particle | grains in a separated liquid. It is a figure which shows the specific structural example of the separation filtration system of a modification. It is a figure explaining an example of the relationship between the filtration time in a filtration apparatus, and the amount of liquid flow in a crushing part.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values and the like shown in this embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the specification and the drawings, elements having substantially the same functions and configurations will be denoted by the same reference numerals to omit repeated description, and elements not directly related to the present invention will not be illustrated. Do.

  FIG. 1 is a diagram showing the configuration of the separation and filtration system 1 of the present embodiment. The separation filtration system 1 generates a clear liquid from a liquid to be treated containing a target substance, and can be applied to various substances (particles). Here, when the target substance (target particles) to be removed from the liquid is a dispersion containing Prussian blue nanoparticles (including Prussian blue-type metal complex nanoparticles) that capture radioactive cesium (cesium ion) Will be explained.

  As shown in FIG. 1, the separation and filtration system 1 includes a treated liquid tank 10, a solid-liquid separation unit 20, a filtration unit 30, and a particle size adjustment unit 50. Contaminated water (hereinafter referred to as "stock solution") in which cesium ions are dissolved and Prussian blue nanoparticles (dispersion liquid containing nanoparticles) as a capture substance for capturing cesium ions are charged into the liquid tank 10 to be treated. Be done. As described above, in the liquid tank 10, Prussian blue nanoparticles are added to the stock solution in which cesium ions are dissolved to generate the liquid. And in the to-be-processed liquid tank 10, a undiluted | stock solution and a prussian blue nanoparticle contact, and the cesium ion currently melt | dissolved in undiluted | stock solution is capture | acquired by prussian blue nanoparticle.

  The solid-liquid separation unit 20 separates the liquid to be treated, which is transported from the liquid tank 10 to be treated, into a concentrate and a separated liquid. The concentrate is Prussian blue nanoparticles (target particles) capturing cesium ions, and the concentrate is returned to the liquid tank 10 to be used repeatedly. However, if it is judged that the capture capacity of cesium ion is limited and the capture capacity has reached the limit, the return to the treated liquid tank 10 is stopped, and the concentrate is outside the system. It is discharged and sent to the post-treatment process.

  The filtration unit 30 filters the separated liquid generated by the solid-liquid separation unit 20 to generate a clear liquid. The filtering unit 30 removes the Prussian blue nanoparticles (target particles) from the separated liquid by letting the separated liquid flow through a filter medium (filter) having filter holes. As a result, cesium ions contained in the solution are removed together with the Prussian blue nanoparticles, and a clear solution is produced. In the filtration unit 30, the target particles are deposited on the filter medium (filter) as a concentrate, but the concentrate is also returned to or stored in the liquid tank 10, like the solid-liquid separation unit 20, It is sent to the post-treatment process.

  The particle size adjustment unit 50 performs a particle size adjustment process to reduce the particle size of at least one of the target particles to be treated, the target particles in the treatment liquid, and the target particles in the separation liquid. Do. Specifically, the particle size adjustment unit 50 performs the particle size adjustment process on the treatment liquid stored in the treatment liquid tank 10 and the treatment liquid transported from the treatment liquid tank 10 to the solid-liquid separation unit 20. The particle size adjustment process is performed on the separated liquid between the solid-liquid separation unit 20 and the filtration unit 30. Furthermore, the particle size adjustment process is performed on the concentrate separated from the separated liquid in the solid-liquid separation unit 20 or the filtration unit 30, and the concentrate after the particle size adjustment process is returned to the liquid tank 10.

  As described above, in the present embodiment, target particles (Prussian blue nanoparticles) contained in the concentrate separated from the separated liquid are returned to the liquid tank 10 to be treated, and are repeatedly used. Although described later in detail, when the target particles are repeatedly charged, the particle size distribution in the separated liquid reaching the filtration unit 30 is biased, and the removal efficiency of the target particles, that is, the filtration efficiency decreases. According to the present embodiment, by reducing the particle size of the target particles (Prussian blue nanoparticles) by the particle size adjustment unit 50, the bias of the particle size distribution in the separated liquid is reduced, and the filtration efficiency in the filtration unit 30 is improved. be able to.

  According to the separation and filtration system 1 of the present embodiment, a process of separating a liquid to be treated containing target particles into a concentrate and a separation liquid, a process of filtering the separation liquid to form a clear liquid, and a process liquid Performing a particle size adjustment process to make target particles smaller with respect to at least one of target particles to be input, target particles in the liquid to be treated, and target particles in the separated liquid; Is realized. Below, after demonstrating the specific structure of the separation filtration system 1, the mechanism of the filtration efficiency improvement by the particle size adjustment part 50 is explained in full detail.

  FIG. 2 is a view showing a specific configuration example of the separation filtration system 1. As described above, the separation and filtration system 1 includes the liquid treatment tank 10. The to-be-treated liquid tank 10 is provided with a stirrer 10a, and the Prussian blue nanoparticles are stirred in the stock solution by driving the stirrer 10a in a state where the stock solution containing cesium ions and the Prussian blue nanoparticles are charged. , The liquid to be treated is produced. The transfer pump P1 is connected to the liquid to be treated tank 10, and the liquid to be treated in the liquid to be treated tank 10 is transferred to the solid-liquid separation unit 20 by driving the transfer pump P1.

  The solid-liquid separation unit 20 includes a centrifugal separator that applies centrifugal force to the liquid to be treated to separate the concentrate and the separated liquid. Here, a screw decanter centrifuge 21 is adopted as a centrifuge. The screw decanter type centrifugal separator 21 rotates the liquid to be treated at high speed in a rotating body, accelerates the settling speed of the concentrate by centrifugal force acting on the liquid to be treated, and promotes solid-liquid separation.

(Screw decanter centrifuge 21)
FIG. 3 is a perspective view showing a schematic configuration example of the screw decanter type centrifuge 21 and FIG. 4 is a longitudinal sectional view showing a schematic configuration example of the screw decanter type centrifuge 21 . For convenience of explanation, FIG. 1 also shows the main internal structure. The screw decanter type centrifugal separator 21 is used in various fields, for example, manufacturing processes for food, drinking water, medicine, chemical products, steel products, etc., water treatment such as human waste treatment, sewage treatment, slurry treatment, and factory wastewater treatment. Used for solid-liquid separation.

  The screw decanter type centrifugal separator 21 includes a casing 22 and a cylindrical outer shell bowl 23 rotatably supported in the casing 22. Then, the outer cylinder bowl 23 is supplied with the liquid to be treated from the feed pipe 24 to the inside, is rotated by the power of the main body driving motor, and centrifuges the concentrate and the separated liquid.

  The inner barrel screw conveyor 25 is configured by spirally winding a screw blade 25a projecting radially outward around the outer periphery of the body 25b, and is rotatable coaxially with the outer barrel bowl 23 in the outer barrel bowl 23. It is pivotally supported. The inner barrel screw conveyor 25 has a rotational speed difference in the same direction and relative to the outer barrel bowl 23 by the power of the differential speed brake 26 and the planetary gear mechanism of the gear box 27. Rotate. Thus, the inner barrel screw conveyor 25 discharges the concentrate deposited on the inner circumferential surface of the outer barrel bowl 23 out of the outer barrel bowl 23 by means of the screw blades 25a.

  FIG. 5 is a view for explaining the operation of the screw decanter centrifuge 21. As shown in FIG. In FIG. 5, the white arrows indicate the flow directions of the liquid to be treated, the concentrate, and the separation liquid, the black dots indicate the concentrate, and the hatched regions indicate the separation liquid.

  As shown in FIG. 5A, the liquid to be treated is supplied to the outer shell bowl 23 through the feed pipe 24 and the inner shell screw conveyor 25. The outer shell bowl 23 and the inner shell screw conveyor 25 rotate at high speed in the same direction as indicated by the solid arrows, and the radial outward centrifugal force through the rotation causes the outer shell bowl 23 to have an inner peripheral surface. The concentrate with high mass density (indicated by x in the figure) is deposited on the radially outer side of and separated from the separation liquid with low mass density (indicated by y in the figure) located radially inward.

  The separated liquid is pressed by the liquid to be treated newly supplied to the outer shell bowl 23 and discharged from the liquid discharge port 23 b provided in the side plate 23 a on the large diameter side of the outer shell bowl 23. At this time, the liquid discharge port 23 b is formed radially inward of the outer diameter of the outer barrel 23. Therefore, the concentrate pressed against the inner peripheral surface of the outer shell bowl 23 by the centrifugal force is difficult to be discharged from the liquid discharge port 23b beyond the side plate 23a, and only a small amount of the concentrate is separated from the liquid discharge port 23b. It is discharged together with the solution. The inner barrel screw conveyor 25 is rotated relative to the outer barrel bowl 23 (for example, +10 to +60 rpm), and the concentrate deposited on the inner circumferential surface of the outer barrel bowl 23 is changed by the screw blade 25a. , Move to the right in FIG. 5 (b).

  Here, the outer cylinder bowl 23 has a conical end on the right side in FIG. 5B, and the concentrate moved by the screw blade 25a is dewatered and the small diameter of the outer cylinder bowl 23 It discharges from the solid discharge port 23c provided in the side. Consecutively separating and producing the concentrate and the separated liquid by continuously supplying the liquid to be treated from the feed pipe 24 while the outer shell bowl 23 and the inner shell screw conveyor 25 are rotating. Is possible.

  In the separation filtration system 1, as shown by a broken arrow in FIG. 2, the concentrate discharged from the screw decanter type centrifuge 21 is returned to the liquid tank 10 to be treated, and is again put into the stock solution. .

  Further, the separation filtration system 1 is provided between the screw decanter type centrifuge 21 (solid-liquid separation unit 20) and the filtration unit 30, and the separation discharged from the liquid outlet 23b of the screw decanter type centrifuge 21. A separated liquid storage unit 40 for storing liquid is provided. The separated liquid storage unit 40 functions as a buffer tank for temporarily storing the separated liquid separated by the screw decanter type centrifuge 21 and is for preventing the precipitation of the concentrate remaining in the separated liquid. A stirrer 40a is provided. The transfer pump P2 is connected to the separated liquid storage unit 40, and the separated liquid in the separated liquid storage unit 40 is transferred to the filtration device 31 as the filtration unit 30 by driving the transfer pump P2.

(Filtering device 31)
6 is a perspective view showing a configuration example of the filtration device 31, and FIG. 7 is a schematic view of a vertical cross section (YZ cross section) along the line VII-VII in FIG. In FIGS. 6 and 7, an X axis (horizontal direction), a Y axis (horizontal direction), and a Z axis (vertical direction) which vertically intersect are defined as illustrated. The filtration device 31 includes a vessel 32 formed of a metal container in which an inlet 32a is formed, and the separated liquid transported from the separated liquid storage unit 40 is introduced into the vessel 32 through the inlet 32a. Ru. Also, in the upper part of the vessel 32, a separated liquid or a gas (for example, nitrogen N ₂ ) is discharged out of the vessel 32 or a compressed gas (for example, compressed nitrogen N ₂ ) is introduced into the vessel 32. The opening 32b is formed.

  In the vessel 32, a filter unit 33 and a register pipe 34 to which the filter unit 33 is connected are accommodated. A plurality of filter units 33 are provided in the vessel 32, and are installed along the vertical direction in the longitudinal direction. On the other hand, a plurality of register pipes 34 are provided in the vessel 32, and are installed along the longitudinal direction in the horizontal direction. The register pipe 34 is suspended above the vessel 32 and is held so that the plurality of filter units 33 vertically hang from one register pipe 34.

  A filter 33a made of a filter cloth having filter holes is provided on the outer peripheral surface of the filter unit 33, and the liquid is pressed from the outer side to the inner side of the filter unit 33, so that the separated liquid is contained by the filter 33a. Concentrate is removed from the separation liquid. Thus, the clear fluid generated by filtering the separated liquid flows in the filter unit 33, and the clear fluid is discharged to the outside of the vessel 32 through the filter unit 33 and the register pipe 34. .

  Here, the filtration device 31 employs a cake filtration system, and deposits such as particles removed from the separated liquid are deposited on the outer surface of the filter 33a to form a deposit deposition layer. As described above, when the deposit is formed on the outer surface of the filter 33a, particles having a particle size smaller than the filter pores of the filter 33a are captured by the deposit, and the target particle removal efficiency, that is, the filtration efficiency is further enhanced. It can be enhanced.

A discharge port 35 and a discharge valve 36 for opening and closing the discharge port 35 are provided on the bottom surface of the vessel 32, and a liquid discharge pipe 37 is provided in the vicinity of the discharge port 35. There is. Although detailed description is omitted, when the filtration process in the filtration device 31 is completed, the drive of the transfer pump P2 is stopped, and compressed gas (for example, compressed nitrogen N ₂ ) is fed into the vessel 32 from the opening 32b to The inside of 32 is pressurized. Thereby, the separated liquid remaining in the vessel 32 is discharged to the outside through the liquid discharge pipe 37. Also, with the discharge valve 36 open, compressed gas (for example, compressed nitrogen N ₂ ) is back blown from the register pipe 34 to peel off the deposit buildup layer (concentrate) formed on the filter 33 a, and the discharge port Evacuate the vessel 32 from 35. In addition, as shown in FIG. 2, the concentrate discharged | emitted from the filtration apparatus 31 will be returned to the to-be-processed liquid tank 10, and will be again thrown in in a undiluted | stock solution. On the other hand, the clear liquid discharged from the register pipe 34 to the outside of the vessel 32 in the filtration step is stored in the clear liquid tank 60.

  As described above, the concentrate discharged from the screw decanter-type centrifuge 21 (solid-liquid separation unit 20) and the filtration apparatus 31 (filtration unit 30) contains Prussian blue nanoparticles, and the liquid to be treated is It is returned to the tank 10 and reintroduced into the stock solution. However, if the concentrate is reloaded, target particles (Prussian blue nanoparticles that have captured cesium ions) can not be removed, or it takes a long time to obtain a clear solution and the filtration rate decreases. And the filtration efficiency is reduced. It is considered that this is because the redistribution of the concentrate causes a deviation in the particle size distribution of particles in the separated liquid transported to the filtration device 31.

  FIG. 8 is a view for explaining an example of the particle size distribution of the deposit deposited layer C formed on the filter 33a. As described above, on the outer surface of the filter 33a in the filtration device 31, deposits such as particles removed from the separation liquid are deposited to form the deposit deposition layer C. Thus, the deposit deposited layer C formed by depositing particles captures particles finer than the filter holes 33c of the filter 33a as a precoated fine film. Here, the dispersion containing Prussian blue nanoparticles is a dispersion having a primary particle diameter of 10 to 50 nm and a secondary particle diameter of 10 nm to 1 mm. And, in order to filter and separate the primary particles, it is necessary to retain 10 to 200 nm particles (hereinafter referred to as “aggregated secondary particles”) 1 to 4 times the primary particles as secondary particles.

  Then, when the amount of aggregated secondary particles necessary for forming the precoated fine film is small, the primary particles almost pass through the filter holes 33c. On the other hand, if there are too many agglomerated secondary particles, flow resistance will increase and filtration efficiency will decrease. Therefore, in the deposit deposited layer C, it is desirable to retain the aggregated secondary particles in an amount of 5 to 30%, more preferably 8 to 20%. The aggregated secondary particles are easily formed in a compact manner, and some particles are about several mm, but they swell and disperse with time.

  For example, as shown in FIG. 8 (a), particles having a relatively large particle size shown by cross hatching in the figure, particles having a relatively small particle size shown in white in the figure, and particles in between (black in the figure) It is preferred that particles of various particle sizes are present, such as hatched). Temporarily, as shown in FIG.8 (b), as the deposit | attachment deposit layer C is formed with the particle | grains with a large particle size (it shows by cross hatching), and the particle | grains with a small particle size (it shows by white), If the particle size is uneven, the precoated fine film is not properly formed, many particles pass through the deposit deposition layer C, and the removal efficiency of the target particles, that is, the filtration efficiency decreases. Also, after a certain time, if particles of small size are deposited between particles of large size, a clear liquid can be obtained, but the filtration rate decreases because the resistance of the layer composed of particles of small size is large. , Become inefficient.

  And, in the separation filtration system 1, while the re-introduction of the concentrate is not performed, the deposit deposited layer C is formed as shown in FIG. 8A, but if the re-introduction of the concentrate is performed, It was found that the deposit deposited layer C was formed as shown in FIG. 8 (b). It is considered that this is mainly due to aggregation of particles by the action of centrifugal force in the screw decanter centrifuge 21.

  FIG. 9 is a view for explaining the particle size distribution of particles in the separated liquid. The particles in the separated liquid after the concentrate is separated from the liquid to be treated in the screw decanter-type centrifuge 21 are, as shown in FIG. Variations occur appropriately, and a deposit deposited layer C is formed on the filter 33a as shown in FIG. 8A. However, in the screw decanter type centrifugal separator 21, when centrifugal force for solid-liquid separation acts, fine particles having the particle size of the meshed portion aggregate as shown in FIG. 9 (b). Most of the particles aggregated in this way are separated as a concentrate by the screw decanter type centrifuge 21, but a part is introduced to the separated liquid reservoir 40 or the filter 30 while being mixed in the separated liquid. As a result, as shown in FIG. 9 (c), the particle size distribution of the particles in the separated liquid is large in the particles having a small particle size not aggregated and the particles having a large particle size which are aggregated and discharged into the separated liquid. As a result, as shown in FIG. 8B, the deposit deposition layer C is formed on the filter 33a.

  Therefore, in the present embodiment, even when the concentrate is centrifuged, as shown in FIG. 9A, the target is to obtain secondary aggregated particles that form a precoated micromembrane capable of separating and filtering nanoparticles. A particle size control unit 50 is provided to crush the material to reduce the particle size.

  Referring to FIG. 2, the particle size adjusting unit 50 sucks the separated liquid stored in the separated liquid storage unit 40, crushes particles in the separated liquid, and returns it to the separated liquid storage unit 40 again. As the particle size adjustment unit 50, a general industrial mixer can be employed, and the specific configuration thereof is not particularly limited. For example, the particle size adjusting unit 50 is a mixer that shears particles in the liquid by rotating a plurality of blades, or a mixer that breaks particles in the liquid by colliding suctioned liquid with a sheared portion at high speed and high pressure. Can be composed of In addition, although the particle size adjusting unit 50 is a mixer that crushes target particles here, the particle size adjusting unit 50 may not grind particles but may grind particles. In any case, the specific configuration of the particle size adjustment unit 50 is not particularly limited as long as the particle size of the target particles can be reduced.

  Since the consolidated aggregated secondary particles forming the precoated fine film are easily loosened by shearing or the like, the concentrate is re-introduced into the liquid tank 10 by crushing particles in the separated liquid by the particle size adjustment unit 50. Also, the particle size distribution shown in FIG. 9 (a) can be maintained. As a result, in the filtering device 31, an appropriate deposit deposition layer C is formed on the filter 33a, and the removal efficiency of target particles, that is, the filtration efficiency can be improved.

  FIG. 10 is a view showing a specific configuration example of the separation filtration system 1a of the modification. The separation filtration system 1a of this modification further includes flow rate detection units S1 and S2 and a control unit 70 in addition to the components of the separation filtration system 1 of the above embodiment. Here, about the same composition as the above-mentioned embodiment, the same numerals as the above are attached, explanation is omitted, and a new composition is explained.

  The flow rate detection unit S1 is provided in a pipe connecting the screw decanter type centrifuge 21 and the separated liquid storage unit 40, and flows into the separated liquid storage unit 40 from the screw decanter type centrifuge 21 (solid-liquid separation unit 20). Detect the inflow of the separated liquid. Further, the flow rate detection unit S2 detects the outflow amount of the separated liquid flowing out of the separated liquid storage unit 40 to the filtration device 31 (filtration unit 30). The flow rate detection units S1 and S2 are electrically connected to the control unit 70, and detection signals are input from the flow rate detection units S1 and S2 to the control unit 70.

  The control unit 70 performs drive control of the particle size adjustment unit 50 according to the inflow amount and the outflow amount of the separation liquid detected by the flow amount detection units S1 and S2. Specifically, when the inflow to the separated liquid storage 40 of the separated liquid becomes equal to or less than a preset threshold, the control unit 70 determines in advance the outflow from the separated liquid storage 40 of the separated liquid. The driving of the particle size adjustment unit 50 is stopped when the threshold value is less than the set threshold value. Here, the driving of the particle size adjusting unit 50 is stopped when the inflow amount and the outflow amount become almost zero or when the inflow and outflow of the separated liquid are completely stopped.

  When the particle size adjustment unit 50 capable of variably controlling the suction amount of the separation liquid, that is, the processing amount is adopted, the control unit 70 responds to the inflow amount, the outflow amount, or the difference between the inflow amount and the outflow amount. , And variably control the particle size adjustment unit 50. That is, the control unit 70 crushes particles in the separated liquid in proportion to the flow rate of the separated liquid flowing into the separated liquid storage unit 40 and the flow rate of the separated liquid flowing out from the separated liquid storage unit 40, and If the inflow or outflow is stopped, the crushing process is discontinued.

  FIG. 11 is a view for explaining an example of the relationship between the filtration circulation time and the filtration rate in the filtration device 31 and the amount of liquid flow in the particle size adjustment unit 50. Here, the filtration circulation time is the time required to produce a certain amount of clear liquid that is at or above an allowable level. The relationship shown in the drawing is established between the filtration circulation time and the filtration rate in the filtration device 31 and the amount of liquid passing through the particle size adjusting unit 50, that is, the amount of crushed particles in the separated liquid. Specifically, until the amount of crushing of particles in the particle size adjustment unit 50 reaches a certain amount, the filtration circulation time becomes shorter as the amount of crushing increases, and the filtration rate becomes larger. However, when the amount of crushing of particles in the particle size adjustment unit 50 exceeds a certain amount, the filtration circulation time in the filtration device 31 becomes longer and the filtration rate becomes smaller.

  This is because if the particles in the separation liquid are crushed too much, the particle size of the particles becomes too small as a whole, and it is not possible to form an appropriate deposit deposited layer C, and the target particles pass through the filter holes 33c. it is conceivable that. Therefore, for example, in the filtration device 31, when the remaining liquid is drained from the vessel 32, or when the deposit deposited layer C (concentrate) is peeled off and discharged from the discharge port 35, etc. If the particle size adjustment unit 50 continues to be driven while the conveyance of the separated liquid from the unit 40 is stopped, the target particles become too small, and the filtration circulation time becomes long and the filtration rate becomes low. According to the separation filtration system 1a of this modification, the inflow of the separated liquid flowing into the separated liquid storage unit 40, or the outflow of the separated liquid flowing out of the separated liquid storage unit 40 into the filtration unit 30 (filtering device 31) Accordingly, since the control unit 70 controls the driving of the particle size adjusting unit 50, the filtration circulation time can be shortened and the filtration rate can be increased.

  In the separation and filtration system 1a of this modification, the flow rate detection units S1 and S2 are provided, but the control unit 70 controls the particle size adjustment unit 50 in conjunction with, for example, the rotation speed of the transfer pumps P1 and P2. Drive control may be performed. In any case, the control unit 70 controls the flow amount of the separated liquid flowing from the solid-liquid separation unit 20 into the separated liquid storage unit 40 and the flow amount of the separated liquid flowing out from the separated liquid storage unit 40 to the filtering unit 30. If the drive control of the particle size adjustment unit 50 is performed according to either one or both, the detailed control content can be designed appropriately.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is obvious that those skilled in the art can conceive of various changes or modifications within the scope of the claims, and it is naturally understood that they are also within the technical scope of the present invention. Be done.

  For example, in the above embodiment, the case where the target substance (target particles) is Prussian blue nanoparticles has been described, but the target particles are not limited. As target particles, in addition to Prussian blue nanoparticles, pigments (for example, metal compound particles, carbon material particles, organic compound particles), toners (for example, carbon material particles, plastic particles, plastic particles, and carbon particles and pigments adsorbed to plastic particles) Materials (eg, metal particles, carbon material particles, silicon particles), electronic materials (eg, semiconductor particles), catalysts (eg, metal particles), sensor materials (eg, metal particles), etc. In the case where these target particles are used, the same function and effect as described above can be realized. Also, the target particles are not limited to nanoparticles, and the particle size is not limited.

  Moreover, although the said embodiment demonstrated the case where the solid-liquid separation part 20 was a centrifuge which makes a to-be-processed liquid act a centrifugal force, and isolate | separates a concentrate and a separation liquid, the solid-liquid separation part 20 Not limited to a centrifuge, for example, solid-liquid separation may be performed by gravity sedimentation. Even in the case where the centrifugal separator is not provided, providing the particle size adjusting unit 50 can bring about an operation and effect of preventing an increase in size of the aggregated secondary particles. In any case, if the solid-liquid separation unit 20 can separate the liquid to be treated containing the target substance (target particles) into the concentrate and the separation liquid, the specific configuration and the treatment method thereof are limited. It is not a thing. However, when the centrifugal separator as in the above embodiment is adopted, the target particles are easily aggregated, so the effect obtained by providing the particle size adjusting unit 50 becomes more remarkable.

  Moreover, the structure of the filtration part 30 in the said embodiment is only an example. In particular, in the above embodiment, the diameter of the filter hole 33c of the filter 33a is set larger than the particle size of the target particle, and the cake filtration method of removing particles having a particle size smaller than the diameter of the filter hole 33c Explained. However, an absolute (diameter) filtration method may be adopted in which the diameter of the filter hole 33c is set to the particle diameter of the target particle or less. Even in this case, since the deposit deposited layer C is formed on the outer surface of the filter 33a, the same function and effect as described above are provided. In addition, since the appropriate deposit deposit layer C is formed, the diameter of the filter hole 33c can be increased, and the flow resistance can be reduced to shorten the filtration circulation time.

  Further, in the above embodiment, the filter 33a having a variation in the diameter of the filter hole 33c has been described as an example. However, a membrane filter having substantially uniform diameter filtration holes may be employed as the filter 33a.

  In the above embodiment, the separated liquid subjected to the particle size adjustment processing in the particle size adjustment unit 50 is returned to the separated liquid storage unit 40, but the separated liquid subjected to the particle size adjustment processing is transported to the filtration unit 30 It is also good. However, by returning the separated liquid subjected to the particle size adjustment processing to the separated liquid storage unit 40 as in the above embodiment, the particle size adjustment processing is repeatedly performed to realize the particle size distribution in which the filtration circulation time is minimized. it can.

  Further, in the above embodiment, both the concentrate removed by the screw decanter type centrifuge 21 and the concentrate removed by the filtering device 31 are returned to the liquid tank 10 to be treated. However, the concentrate may be returned only from either one of the screw decanter type centrifuge 21 and the filtration device 31, and furthermore, in the system of the separation filtration system 1, the return of the concentrate is not performed. It is also good. For example, only the concentrate (target particles) removed by another separation filtration system 1 is charged into the liquid tank 10 to be treated. Even in this case, the filtration efficiency can be improved by providing the particle size adjusting unit 50 as in the above embodiment.

  Also, for example, the particle size adjustment unit 50 may be provided in series downstream of the transfer pump P2 (liquid transfer device) that sends the separated liquid to the filtration unit 30.

  The present invention can be used in a separation filtration system and separation filtration method in which target particles in a liquid to be treated are separated and filtered to form a clear liquid.

1 separation filtration system 1a separation filtration system 20 solid-liquid separation unit 30 filtration unit 40 separation liquid storage unit 50 particle size adjustment unit 70 control unit

Claims (9)

A solid-liquid separation unit for separating a liquid to be treated containing a target substance into a concentrate and a separation liquid;
A filtration unit for filtering the separated liquid from which the concentrate is separated in the solid-liquid separation unit;
A separated liquid storage unit provided between the solid-liquid separation unit and the filtration unit and storing the separated liquid generated by the solid-liquid separation unit;
A particle size adjustment unit that performs a particle size adjustment process to reduce the particle size of the target substance to the separated liquid stored in the separated liquid storage unit ;
Depending on one or both of the inflow of the separated liquid flowing from the solid-liquid separation unit into the separated liquid storage unit, and the outflow of the separated liquid flowing out from the separated liquid storage unit to the filtration unit, A control unit that performs drive control of the particle size adjustment unit;
A separation filtration system characterized by comprising.   The separation and filtration system according to claim 1, wherein the particle size adjusting unit breaks the target material in the particle size adjusting process to reduce the particle size.   The separation and filtration system according to claim 1 or 2, wherein the target substance is a dispersion containing nanoparticles, and the nanoparticles are separated and filtered. The separation filtration system according to claim 3 , wherein the nanoparticles are Prussian blue nanoparticles. The liquid processing apparatus further comprises a liquid treatment tank for storing the liquid to be treated in which the Prussian blue nanoparticles are charged in a stock solution in which cesium ions are dissolved;
A concentrate containing the Prussian blue nanoparticles, which has been captured by the cesium ion and removed by at least one of the solid-liquid separation unit and the filtration unit, is reintroduced into the liquid tank to be treated. The separation filtration system according to claim 4 . The separation and filtration system according to any one of claims 1 to 5 , wherein the particle size adjustment unit returns the separated liquid after the particle size adjustment processing to the separated liquid storage unit. The said control part stops the drive of the said particle size adjustment part, when the inflow amount or outflow amount of the said isolation | separation liquid becomes below in the preset threshold value, The said claim | item 1 characterized by the above-mentioned. Separation filtration system. 8. The solid-liquid separation unit according to any one of claims 1 to 7 , wherein the solid-liquid separation unit includes a centrifugal separator that applies centrifugal force to the liquid to be treated to separate the concentrate and the separated liquid. Separation filtration system as described. Separating the liquid to be treated containing the target substance into a concentrate and a separation liquid;
Storing the separated liquid in a separated liquid storage unit;
Filtering the separated liquid to produce a clear liquid;
Performing a particle size adjustment process to reduce the particle size of the target substance to the separated liquid stored in the separated liquid storage unit ;
And d) performing drive control of the particle size adjustment processing according to one or both of the inflow of the separated liquid flowing into the separated liquid storage section and the flowed out amount of the separated liquid flowing out from the separated liquid storage section; ,
A separation filtration method characterized in that

Images