WO2016076042A1 - Downflow-type filtration tower - Google Patents

Downflow-type filtration tower Download PDF

Info

Publication number
WO2016076042A1
WO2016076042A1 PCT/JP2015/078559 JP2015078559W WO2016076042A1 WO 2016076042 A1 WO2016076042 A1 WO 2016076042A1 JP 2015078559 W JP2015078559 W JP 2015078559W WO 2016076042 A1 WO2016076042 A1 WO 2016076042A1
Authority
WO
WIPO (PCT)
Prior art keywords
filtration
particles
cleaning
filtration chamber
cleaning particles
Prior art date
Application number
PCT/JP2015/078559
Other languages
French (fr)
Japanese (ja)
Inventor
柏原　秀樹
Original Assignee
住友電気工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 住友電気工業株式会社 filed Critical 住友電気工業株式会社
Priority to JP2015559368A priority Critical patent/JPWO2016076042A1/en
Publication of WO2016076042A1 publication Critical patent/WO2016076042A1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration

Definitions

  • the present invention relates to a downflow filter tower.
  • a filtration tower containing filtration particles is used as a method for separating and removing oil and turbidity at a low cost.
  • oil and turbidity are filtered by a filtration layer formed by enclosed filtration particles.
  • wash water is passed through the filter tower in the direction opposite to the normal water flow direction to adhere to the filter particles.
  • a washing process for removing the oil and turbidity, so-called back washing is performed.
  • the above publication proposes using a resin fiber filter medium having a small specific gravity as the filter particles forming the upper layer and using a porous ceramic filter medium having a large specific gravity as the filter particles forming the lower layer.
  • the sedimentation rate of granular materials increases as the particle size increases. Accordingly, when trying to stratify due to the difference in sedimentation speed, the gap between particles tends to be larger in the lower layer, and there is a possibility that fine turbidity or the like cannot be captured in the lower layer. For this reason, in the structure of the said gazette, the difference of the sedimentation rate is ensured by the combination of the resin fiber filter medium and the porous ceramics filter medium.
  • the present invention has been made based on the above-described circumstances, and an object of the present invention is to provide a filtration tower that can remove fine oil and turbidity and is excellent in the washing performance of filtration particles.
  • a filtration tower according to an aspect of the present invention made to solve the above problems is a downward flow filtration tower including a plurality of filtration chambers partitioned by a plurality of water-permeable partition plates. Each filtration chamber is filled with filtration particles and washing particles, and the average particle size and average specific gravity of the washing particles in the filtration chamber are larger than the washing particles in the filtration chamber immediately below the filtration chamber.
  • the downflow filter tower according to one embodiment of the present invention can remove fine oil and turbidity and is excellent in cleaning performance of the filter particles.
  • FIG. 1 is a schematic cross-sectional view showing a downflow filtration tower according to an embodiment of the present invention.
  • a filtration tower is a downward flow filtration tower including a plurality of filtration chambers partitioned by a plurality of water-permeable partition plates, and each of the plurality of filtration chambers includes filtration particles and cleaning particles.
  • the average particle size and average specific gravity of the cleaning particles in the filtration chamber are larger than the cleaning particles in the filtration chamber immediately below the filtration chamber (except for the lowermost filtration chamber).
  • the down-flow type filtration tower includes a plurality of filtration chambers filled with filtration particles and washing particles, so that a layer of filtration particles solidified with oil or turbidity in each filtration chamber during backwashing can be obtained by washing particles.
  • the cleaning effect of the filtration particles can be promoted by splitting.
  • the upper filtration chamber is filled with cleaning particles having a larger average particle diameter and average specific gravity, so that the upper filtration chamber has a higher settling rate of the cleaning particles. Thereby, it becomes possible to use filtration particles having a larger particle size and a higher sedimentation rate in the upper filtration chamber.
  • each said filtration chamber is each filled with washing
  • the average particle size of the cleaning particles in the filtration chamber is preferably 1.5 to 10 times the average particle size of the cleaning particles immediately below the filtration chamber.
  • the improvement of ability is more certain.
  • the average specific gravity of the cleaning particles in the filtration chamber is preferably 1.1 to 2 times the average specific gravity of the cleaning particles in the filtration chamber immediately below the filtration chamber. In this way, by setting the ratio of the average specific gravity of the cleaning particles between adjacent filtration chambers within the above range, clogging can be avoided and filtration capacity can be selected by selecting the average particle size, average specific gravity, etc. of the filtration particles in each filtration chamber. The improvement is further ensured.
  • the filling mass ratio of the cleaning particles in the filtration chamber is preferably larger than the filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber.
  • the difference between the filling mass ratio of the cleaning particles in the filtration chamber and the filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber is preferably 5% or more and 20% or less.
  • the average particle size and average specific gravity of the cleaning particles in one filtration chamber may be larger than the filtration particles in the same filtration chamber. In this way, by making the average particle diameter and average specific gravity of the cleaning particles larger than that of the filtering particles in each filtering chamber, the lower cleaning particle layer and the upper filtering particle layer are efficiently separated due to the difference in sedimentation speed. Can be stratified. As a result, the removal of oil and turbidity is not hindered.
  • the “average particle diameter” is a sieve defined in JIS-Z8801-1 (2006), and sieved in order from a sieve having a large mesh size, and the mass ratio of particles passing through the mesh is measured. It means a value (d50) at which the integrated mass becomes 50% in the particle size distribution created with the nominal aperture as the particle size.
  • “Average specific gravity” is a value measured in accordance with JIS-Z8807 (2012).
  • the “turbidity” means a suspended substance excluding oil.
  • the “oil” and “turbidity” do not have to be separated, and an emulsion may be formed.
  • the “filling mass ratio” of the cleaning particles means the ratio of the mass of the cleaning particles to the total mass of the filtering particles and the cleaning particles filled in each filtration chamber.
  • the downflow type filtration tower in FIG. 1 is a device that filters the liquid to be treated from the top to the bottom.
  • the liquid to be treated to be filtered by the downflow type filtration tower typically includes petroleum-associated water containing oil and turbidity.
  • the turbidity includes, for example, particles such as sand, silica and calcium carbonate, iron powder, microorganisms, and wood chips.
  • the downflow type filtration tower is erected so that the center axis substantially coincides with the vertical direction, and is disposed substantially horizontally on the tubular body 1 having a top plate portion and a bottom plate portion, and the tubular body 1,
  • a pair of water-permeable first to third upper partition plates 2a, 2b, and 2c partitioning the inner space of the cylindrical main body 1 and the upper partition plates 2a, 2b, and 2c, and the inner space of the cylindrical main body 1 Permeable first to third lower partition plates 3a, 3b, 3c.
  • the first filtration chamber 4a is defined in the cylindrical main body 1 between the first upper partition plate 2a and the first lower partition plate 3a in order from the upper side.
  • a second filtration chamber 4b is defined between the second upper partition plate 2b and the second lower partition plate 3b, and a third filtration chamber is disposed between the third upper partition plate 2c and the third lower partition plate 3c. 4c is defined.
  • the downflow type filtration tower is a treatment liquid supply channel 5 for supplying the liquid to be treated to the cylindrical main body 1 from its upper end, and a treatment obtained by filtration of the liquid to be treated inside the cylindrical main body 1.
  • a treated liquid discharge channel 6 for discharging the finished liquid from the lower end of the cylindrical main body 1 is further provided.
  • the first filtration chamber 4a defined inside the cylindrical body 1 is filled with the first filtration particles 7a and the first cleaning particles 8a having an average particle size and an average specific gravity larger than the first filtration particles 7a. Yes. Moreover, the 1st filtration chamber 4a has the 1st head space 9a above the 1st filtration particle
  • the second filtration chamber 4b is filled with the second filtration particles 7b and the second cleaning particles 8b having an average particle diameter and an average specific gravity larger than those of the second filtration particles 7b.
  • the second filtration chamber 4b has a second head space 9b above the second filtration particles 7b and the second cleaning particles 8b in a steady state (a state in which filtration is continuously performed).
  • the third filtration chamber 4c is filled with third filtration particles 7c and third cleaning particles 8c having an average particle diameter and an average specific gravity larger than those of the third filtration particles 7c.
  • the third filtration chamber 4c has a third head space 9c above the third filtration particles 7c and the third cleaning particles 8c in a steady state (a state in which filtration is continuously performed).
  • the cylindrical main body 1 is formed of metal or resin so as to have a strength that can withstand the pressure of the liquid that is inserted into the cylindrical main body 1.
  • Examples of the material for forming the cylindrical body 1 include stainless steel, acrylonitrile-butadiene-styrene copolymer (ABS resin), glass fiber reinforced plastic, or carbon fiber reinforced plastic from the viewpoint of strength, heat resistance, chemical resistance, and the like. preferable.
  • the cylindrical main body 1 may be provided with a reinforcing member or a leg member for self-standing on the outside.
  • the planar shape of the cylindrical main body 1 is not particularly limited, and may be any shape such as a circle, an ellipse, a rectangle, etc., but it is easy to form a uniform liquid flow. From the viewpoint of preventing clogging and staying of cleaning particles and oil and turbidity, a shape without corners is preferable, and a circular shape is typically used. Moreover, making the planar shape of the cylindrical main body 1 without a corner has an advantage that the strength of the cylindrical main body 1 can be easily obtained and the design can be facilitated.
  • the top plate portion where the liquid supply flow path 5 to be processed and the bottom plate portion where the processed liquid discharge flow path 6 are arranged may be flat plates, but pressure resistance is obtained. It is preferable to use a mirror-plate shape.
  • the size of the cylindrical main body 1 is not particularly limited, and is selected according to the flow rate of water to be treated to be treated.
  • the average cross-sectional area of the cylindrical main body 1 can be, for example, 0.1 m 2 or more 10 m 2 or less.
  • the height of the cylindrical main body 1 it can be set to 0.5 m or more and 10 m or less, for example.
  • the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c are formed of plate-like members that allow water to pass therethrough and not allow the filtered particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c to pass therethrough. Is done. These lower partition plates 3a, 3b, 3c and upper partition plates 2a, 2b, 2c seal the filtration particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c inside the filtration chambers 4a, 4b, 4c. Fulfills the function of
  • the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c include, for example, a porous plate having a large porosity, a plate formed with a large number of small holes, a wire mesh, and the like. Can be mentioned.
  • the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c are a support member having a large mesh and a net-like, woven or non-woven fabric provided so as to cover the eyes of the support member. It may consist of a combination with these members.
  • the material of the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c is not particularly limited, and metal, synthetic resin, or the like can be used.
  • metal it is preferable to use corrosion-resistant stainless steel (for example, SUS316L) from the viewpoint of corrosion prevention.
  • a support member such as a reinforcing wire in combination so that the opening is not changed by the water pressure or the weight of the particles.
  • a wire mesh it is preferable to use a mesh made of a wire material having excellent strength and heat resistance, such as stainless steel wire, Kevlar fiber, carbon fiber and the like.
  • the nominal mesh openings of the wire mesh are the corresponding filtration particles 7a, 7b, 7c and cleaning particles 8a, 8b, It is preferably designed to be less than the minimum particle size of 8c. Moreover, when the minimum particle diameter of the filtration particles 7a, 7b, 7c or the cleaning particles 8a, 8b, 8c is very small, if the opening of the wire mesh is made smaller than that, the differential pressure may become too large.
  • the nominal mesh opening of the wire mesh is not more than a value obtained by subtracting the standard deviation of the particle diameters of the corresponding filtration particles 7a, 7b, 7c from the average particle diameter of the corresponding filtration particles 7a, 7b, 7c. .
  • the filtration particles 7a, 7b, and 7c are filter media that form a layer for filtering the water to be treated.
  • known filtration particles can be used, for example, particles mainly composed of natural sand, inorganic particles, ceramics, polymers (polymer compounds), natural organic materials, and the like. Can be used.
  • the filtration particles 7a, 7b, and 7c have a polymer as a main component.
  • the cost and weight of the filtration chambers 4a, 4b, and 4c can be reduced.
  • grains 7a, 7b, 7c can be made small by using a polymer, the washing
  • Examples of the polymer as the main component of the filtration particles 7a, 7b, and 7c include a fluororesin, a vinyl resin, a polyolefin, a polyurethane, an epoxy resin, an acrylic resin, a polyester, a polyamide, a polyimide, a melamine resin, and a polycarbonate. .
  • a fluororesin, a vinyl resin, a polyurethane, an epoxy resin, and an acrylic resin excellent in water resistance and oil resistance are preferable, and a fluororesin excellent in corrosion resistance and a polyolefin excellent in adsorptivity are more preferable.
  • polypropylene that is particularly excellent in oil adsorption capacity is preferable.
  • the fluororesin is excellent in strength, heat resistance, and chemical resistance, and has a relatively large specific gravity, so that it has a merit that it can settle quickly after washing and can be quickly filtered.
  • grains 7a, 7b, 7c may differ for every filtration chamber, and may contain multiple types of particle
  • examples of the natural sand include anthracite, garnet, manganese sand, and the like, and these can be used alone or in combination of two or more.
  • the ceramic for example, ceramic particles mainly composed of silica, alumina, glass or the like can be used.
  • the natural organic material a natural organic material having a particle size adjusted by sieving can be used, and examples thereof include natural fibers such as walnut shell, sawdust and hemp.
  • glass beads are preferable in that particles having a uniform particle size and specific gravity can be obtained relatively easily.
  • Particularly preferable glass beads include, for example, spherical glass beads containing alumina. Such glass beads have an advantage that they are difficult to grow into a lump even when oil adheres, and are easy to disperse and flow during washing. Therefore, stable filtration performance and high cleaning effect can be obtained by using such glass beads.
  • the shape of the filtration particles 7a, 7b, and 7c is not particularly limited, and may be any shape such as a spherical shape or a column shape.
  • the filtration particles 7a, 7b, and 7c can be densely deposited, and the filtration efficiency is improved and the filtration particles 7a in a steady state. , 7b, 7c can be prevented.
  • the average particle diameter of the filtration particles 7a, 7b and 7c is larger as the upper filtration chamber is filled. That is, the average particle diameter of the second filtration particles 7b in the second filtration chamber 4b immediately below the average particle diameter of the first filtration particles 7a in the first filtration chamber 4a is smaller, and the second filtration particles in the second filtration chamber 4b. The average particle diameter of the third filtration particles 7c in the third filtration chamber 4c immediately below the average particle diameter of 7b is smaller.
  • the lower limit of the average particle diameter of the uppermost first filtration particle 7a is preferably 200 ⁇ m, more preferably 250 ⁇ m, and even more preferably 300 ⁇ m.
  • the upper limit of the average particle diameter of the first filter particles 7a is preferably 2000 ⁇ m, more preferably 800 ⁇ m, further preferably 600 ⁇ m, and particularly preferably 400 ⁇ m.
  • the average particle diameter of the first filtration particles 7a is less than the lower limit, the density of the layer formed by the first filtration particles 7a in the first filtration chamber 4a is large and the gap is small. There is a possibility that the pressure loss is increased and the frequency of clogging of the first filtration chamber 4a is increased.
  • the average particle diameter of the 1st filtration particle 7a exceeds the said upper limit, the clearance gap between the 1st filtration particles 7a becomes large, and there exists a possibility that an oil component and turbidity cannot fully be removed.
  • the lower limit of the average particle diameter of the second filtration particles 7b is preferably 80 ⁇ m, more preferably 100 ⁇ m, and even more preferably 120 ⁇ m.
  • the upper limit of the average particle diameter of the second filtration particles 7b is preferably 500 ⁇ m, more preferably 300 ⁇ m, still more preferably 250 ⁇ m, and particularly preferably 200 ⁇ m.
  • the lower limit of the average particle diameter of the lowermost third filtration particle 7c is preferably 5 ⁇ m, more preferably 10 ⁇ m, and further preferably 20 ⁇ m.
  • the upper limit of the average particle size of the third filtration particles 7c is preferably 200 ⁇ m, more preferably 120 ⁇ m, still more preferably 100 ⁇ m, and particularly preferably 80 ⁇ m.
  • the average particle size of the third filtration particles 7c is less than the lower limit, the pressure loss of the third filtration chamber 4c may increase, and the cost and weight may increase.
  • the average particle diameter of the 3rd filtration particle 7c exceeds the said upper limit, there exists a possibility that the said downward flow type filtration tower cannot remove a fine oil droplet and turbidity.
  • the lower limit of the average specific gravity of the filtration particles 7a, 7b, 7c for each of the filtration chambers 4a, 4b, 4c is preferably 1.1, more preferably 1.4.
  • the upper limit of the average specific gravity of the filtration particles 7a, 7b, 7c is preferably 8, and more preferably 5.
  • the average specific gravity of the filtration particles 7a, 7b, 7c is less than the lower limit, the filtration particles 7a, 7b, 7c do not settle, and a layer for filtering the liquid to be treated cannot be formed in the filtration chambers 4a, 4b, 4c. There is a fear.
  • the average specific gravity of the filtration particles 7a, 7b, 7c exceeds the above upper limit, the layer of the filtration particles 7a, 7b, 7c cannot be fluidized during backwashing, and the cleaning effect may not be improved.
  • the average specific gravity of the filtration particles 7a, 7b, and 7c may be different for each filtration chamber.
  • the lower limit of the uniformity coefficient of the filtration particles 7a, 7b, 7c for the filtration chambers 4a, 4b, 4c is preferably 1.1, and more preferably 1.3.
  • the upper limit of the uniformity coefficient of the filtration particles 7a, 7b, and 7c is preferably 1.8, and more preferably 1.6.
  • the uniformity coefficient of the filtration particles 7a, 7b, and 7c is less than the lower limit, the variation in the particle diameter of the filtration particles 7a, 7b, and 7c may be too small to be densely deposited.
  • the “uniformity coefficient” is a sieve defined in JIS-Z8801-1 (2006), and the mass ratio of particles passing through the openings is measured by sieving in order from the sieve with the larger openings. This is a value obtained by dividing the value (d60) at which the integrated mass is 60% in the particle size distribution created by using the aperture as the particle size by the value (d10) at which the integrated mass is 10%.
  • the average thickness of the layer formed by the uppermost first filtration particle 7a in the steady state is not particularly limited, but may be, for example, 10 cm or more and 1 m or less. Although it does not specifically limit as average thickness of the layer which the 2nd filtration particle 7b forms in a steady state, For example, it can be 5 cm or more and 80 cm or less. In addition, the average thickness of the layer formed by the lowermost third filtration particle 7c in the steady state is not particularly limited, but may be, for example, 1 cm or more and 50 cm or less.
  • the cleaning particles 8a, 8b, and 8c rise at the time of backwashing and loosen the layer of the filtration particles 7a, 7b, and 7c solidified by oil and turbidity to form a gap, thereby cleaning the filtering particles 7a, 7b, and 7c. Promote.
  • the cleaning particles 8a, 8b, 8c particles mainly composed of natural sand, inorganic substances, ceramics, metals (including metal compounds), polymers, natural organic materials, etc. can be used. Particles based on polymers are preferred. Since the main component of the cleaning particles 8a, 8b, and 8c is ceramic, metal, or polymer, the ratio of specific gravity with respect to the filtering particles 7a, 7b, and 7c can be easily optimized, and the cleaning effect of the filtering particles 7a, 7b, and 7c can be improved. Easy to get.
  • the material of the cleaning particles 8a, 8b, and 8c may be different for each filtration chamber, and may include a plurality of types of particles.
  • Ceramics that are the main components of the cleaning particles 8a, 8b, and 8c include those containing glass, silica, alumina, and the like as main components.
  • Examples of the metal that is the main component of the cleaning particles 8a, 8b, and 8c include iron oxide having excellent rust resistance.
  • Examples of the polymer that is the main component of the cleaning particles 8a, 8b, and 8c include a fluororesin, vinyl resin, polyolefin, polyurethane, epoxy resin, acrylic resin, polyester, polyamide, polyimide, melamine resin, and polycarbonate. .
  • a fluororesin, a vinyl resin, a polyurethane, an epoxy resin, and an acrylic resin excellent in water resistance and oil resistance are preferable, and a fluororesin excellent in corrosion resistance is more preferable.
  • examples of natural sand that is the main component of the cleaning particles 8a, 8b, and 8c include anthracite, garnet, and manganese sand.
  • a natural organic material having a particle size adjusted by sieving can be used as the natural organic material which is the main component of the cleaning particles 8a, 8b and 8c.
  • glass beads can be mentioned. Since glass beads having a uniform particle size and specific gravity can be obtained relatively easily, a stable cleaning effect can be provided. As particularly preferred glass beads, for example, spherical glass beads containing alumina can be used. Such glass beads have an advantage that they are difficult to grow into a lump even when oil adheres, and are easy to disperse and flow during washing.
  • the shape of the cleaning particles 8a, 8b, and 8c is not particularly limited, and may be any shape such as a spherical shape or a column shape.
  • irregularly pulverized particles as the cleaning particles 8a, 8b, and 8c, it is possible to further promote the cleaning effect of the filtered particles during backwashing.
  • the first cleaning particles 8a have a larger average particle size and average specific gravity than the first filtration particles 7a
  • the second cleaning particles 8b have a larger average particle size and average specific gravity than the second filtration particles 7b
  • the third cleaning particles 8c It is preferable that an average particle diameter and an average specific gravity are larger than the 3rd filtration particle 7c.
  • the average particle diameter and average specific gravity of the cleaning particles 8a, 8b, and 8c are larger than those of the filtration particles 7a, 7b, and 7c in the same filtration chamber 4a, 4b, and 4c, the lower cleaning is performed due to the difference in sedimentation speed.
  • the layer of the particles 8a, 8b, and 8c and the layer of the upper filtration particles 7a, 7b, and 7c can be efficiently divided into layers.
  • the ratio of the average particle size of the first cleaning particles 8a to the average particle size of the first filtered particles 7a, the ratio of the average particle size of the second cleaning particles 8b to the average particle size of the second filtered particles 7b, and the third cleaning particles 8c As a lower limit of the ratio of the average particle diameter to the average particle diameter of the third filtered particles 7c, 1.2 is preferable, and 1.5 is more preferable. On the other hand, the upper limit of the ratio of the average particle diameter is preferably 10, and more preferably 8.
  • the ratio of the average particle diameter is less than the lower limit, the collision energy of the cleaning particles 8a, 8b, and 8c with respect to the filtration particles 7a, 7b, and 7c during backwashing is small, and the layers of the filtration particles 7a, 7b, and 7c are broken up. There is a possibility that the cleaning particles 8a, 8b, and 8c do not settle before the filtering particles 7a, 7b, and 7c after backwashing, and a layer of the filtering particles 7a, 7b, and 7c cannot be formed. On the other hand, when the ratio of the average particle diameters exceeds the upper limit, the filtration particles 7a, 7b, 7c may enter the gaps between the cleaning particles 8a, 8b, 8c and may not form a sufficiently thick filtration layer. .
  • the lower limit of the ratio of the third filtered particles 7c to the average specific gravity is preferably 1.5 and more preferably 2.
  • the upper limit of the ratio of the average specific gravity is preferably 10, and more preferably 8.
  • the ratio of the average specific gravity is less than the lower limit, the collision energy of the cleaning particles 8a, 8b, and 8c with the filtering particles 7a, 7b, and 7c during backwashing is small, and the layers of the filtering particles 7a, 7b, and 7c are broken up.
  • the cleaning particles 8a, 8b, 8c may not settle before the filtered particles 7a, 7b, 7c after backwashing, and the layers of the filtered particles 7a, 7b, 7c may not be formed.
  • the ratio of the average specific gravity exceeds the upper limit, the filtration particles 7a, 7b, 7c may enter the gaps between the cleaning particles 8a, 8b, 8c, and a filtration layer having a sufficient thickness may not be formed.
  • the first cleaning particles 8a have a larger average particle size and average specific gravity than the second cleaning particles 8b in the second filtration chamber 4b directly below, and the second cleaning particles 8b are the third cleaning particles in the third filtration chamber 4c directly below. Average particle diameter and average specific gravity are larger than 8c.
  • the ratio of the average particle size of the first cleaning particles 8a to the average particle size of the second cleaning particles 8b, and the ratio of the average particle size of the second cleaning particles 8b to the average particle size of the third cleaning particles 8c, that is, each filtration chamber The lower limit of the ratio of the average particle diameter of the cleaning particles to the average particle diameter of the cleaning particles in the filtration chamber immediately below the filtration chamber is preferably 1.5 and more preferably 2.
  • the upper limit of the average particle size ratio is preferably 10, and more preferably 8.
  • the ratio of the average particle diameter is less than the lower limit, a sufficient difference in the average particle diameter of the filtration particles cannot be made between adjacent filtration chambers, and the filtration particles formed in the lower filtration chamber There is a risk that the filtration capacity of the layer will be insufficient. Conversely, if the ratio of the average particle diameter exceeds the upper limit, the difference in the average particle diameter of the filtration particles between adjacent filtration chambers is excessive, and the layer of filtration particles formed in the lower filtration chamber is oily. There is a risk of clogging due to turbidity.
  • the lower limit of the average particle diameter of the uppermost first cleaning particle 8a is preferably 250 ⁇ m, more preferably 300 ⁇ m, and further preferably 350 ⁇ m.
  • the upper limit of the average particle size of the first cleaning particles 8a is preferably 3000 ⁇ m, more preferably 2400 ⁇ m, further preferably 1800 ⁇ m, and particularly preferably 1200 ⁇ m.
  • the average particle diameter of the first cleaning particles 8a is less than the lower limit, the density of the layer formed by the first cleaning particles 8a is large, and the pressure loss may increase.
  • the average particle size of the first cleaning particles 8a exceeds the above upper limit, the first filtration particles 7a may enter the gaps between the first cleaning particles 8a, and the layer of the first filtration particles 7a may not be efficiently formed. is there.
  • the lower limit of the average particle size of the second cleaning particles 8b is preferably 100 ⁇ m, more preferably 120 ⁇ m, and even more preferably 150 ⁇ m.
  • the upper limit of the average particle size of the second cleaning particles 8b is preferably 1500 ⁇ m, more preferably 900 ⁇ m, further preferably 750 ⁇ m, and particularly preferably 600 ⁇ m. If the average particle size of the second cleaning particles 8b is less than the lower limit, the density of the layer formed by the second cleaning particles 8b may be large and the pressure loss may increase. Conversely, when the average particle size of the second cleaning particles 8b exceeds the above upper limit, the second filtration particles 7b may enter the gaps between the second cleaning particles 8b, and the layer of the second filtration particles 7b may not be formed efficiently. is there.
  • the lower limit of the average particle diameter of the lowermost third cleaning particle 8c is preferably 6 ⁇ m, more preferably 12 ⁇ m, and even more preferably 25 ⁇ m.
  • the upper limit of the average particle size of the third cleaning particles 8c is preferably 500 ⁇ m, more preferably 350 ⁇ m, further preferably 300 ⁇ m, and particularly preferably 250 ⁇ m.
  • the average particle size of the third cleaning particles 8c is less than the lower limit, the density of the layer formed by the third cleaning particles 8c is large, and the pressure loss may be increased.
  • the third filtration particles 7c may enter the gaps between the third cleaning particles 8c, and the third filtration particle 7c layer may not be formed efficiently. is there.
  • the lower limit of the uniformity coefficient of the cleaning particles 8a, 8b, 8c for each of the filtration chambers 4a, 4b, 4c is preferably 1.1 and more preferably 1.3.
  • the upper limit of the uniformity coefficient of the cleaning particles 8a, 8b, and 8c is preferably 1.8 and more preferably 1.6.
  • the uniformity coefficient of the cleaning particles 8a, 8b, and 8c is less than the above lower limit, the variation in the particle size of the cleaning particles 8a, 8b, and 8c is too small and the cleaning efficiency of the filtration particles 7a, 7b, and 7c becomes insufficient. There is a fear.
  • the uniformity coefficient of the cleaning particles 8a, 8b, and 8c exceeds the upper limit, the gap between the cleaning particles 8a, 8b, and 8c may become small and clogged with oil droplets or turbidity.
  • the lower limit of the ratio of the specific gravity to the average specific gravity of the cleaning particles in the filtration chamber immediately below is preferably 1.1, and more preferably 1.2.
  • the upper limit of the average specific gravity ratio is preferably 2, and more preferably 1.8.
  • the ratio of the average specific gravity is less than the lower limit, it is not possible to make a sufficient difference in the average specific gravity of the filtration particles between the adjacent filtration chambers, and the filtration particle layer formed in the lower filtration chamber There is a risk of insufficient filtration capacity. Conversely, when the ratio of the average specific gravity exceeds the upper limit, the difference in the average specific gravity of the filtration particles between adjacent filtration chambers becomes excessive, and the layer of filtration particles formed in the lower filtration chamber becomes oily or turbid. There is a risk of clogging with quality.
  • the lower limit of the average specific gravity of the uppermost first cleaning particle 8a is preferably 1.5 and more preferably 2.
  • the upper limit of the average specific gravity of the first cleaning particles 8a is preferably 15, and more preferably 10.
  • grains 8a is less than the said minimum, there exists a possibility that sedimentation rate may become small and layering with the 1st filtration particle 7a may become inadequate.
  • the average specific gravity of the first cleaning particles 8a exceeds the above upper limit, the first cleaning particles 8a do not float during backwashing, and the cleaning of the first filtration particles 7a may not be promoted.
  • the lower limit of the average specific gravity of the second cleaning particles 8b is preferably 1.3 and more preferably 1.7.
  • the upper limit of the average specific gravity of the second cleaning particles 8b is preferably 10, and more preferably 7.
  • the average specific gravity of the second cleaning particles 8b is less than the above lower limit, the sedimentation speed is decreased, and there is a possibility that the layering with the second filtration particles 7b is insufficient.
  • the average specific gravity of the second cleaning particles 8b exceeds the above upper limit, the second cleaning particles 8b do not float during backwashing, and the cleaning of the second filtration particles 7b may not be promoted.
  • the lower limit of the average specific gravity of the lowermost third cleaning particle 8c is preferably 1.1, and more preferably 1.5.
  • the upper limit of the average specific gravity of the third cleaning particles 8c is preferably 7, and more preferably 5.
  • grains 8c is less than the said minimum, there exists a possibility that sedimentation rate may become small and layering with the 3rd filtration particle
  • the average specific gravity of the third cleaning particles 8c exceeds the above upper limit, the third cleaning particles 8c do not float during backwashing, and there is a possibility that the cleaning of the third filtration particles 7c cannot be promoted.
  • the filling mass ratio of the cleaning particles in the filtration chamber is preferably larger than the filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber. That is, it is preferable that the filling mass ratio of the cleaning particles 8a, 8b, and 8c in the filtration chambers 4a, 4b, and 4c is larger in the upper filtration chamber. Since the dirt of the filtration particles 7a, 7b, and 7c becomes larger in the upper filtration chamber, the filtration particles 7a, 7b, and 7c can be efficiently washed by increasing the filling mass ratio of the washing particles in the upper filtration chamber. By reducing the height of the lower filtration chamber, the downflow filtration tower can be miniaturized.
  • Difference between the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c that is, the filling mass ratio of the cleaning particles in each filtration chamber and the filling mass of the cleaning particles in the filtration chamber immediately below the filtration chamber
  • the upper limit of the difference in the filling mass ratio is preferably 20%, more preferably 15%.
  • the cleaning particles in the upper filtration chamber may be reduced and the cleaning efficiency of the filtration particles may be insufficient, or the cleaning particles in the lower filtration chamber may be increased. There is a possibility that the counter-flow filter tower becomes unnecessarily large.
  • the difference in the filling mass ratio exceeds the upper limit, the upper cleaning particles increase, the downflow filtration tower may become unnecessarily large, and the cleaning particles in the lower filtration chamber decrease. There is a possibility that the cleaning efficiency of the filtered particles may be insufficient.
  • the filling mass ratio of the 1st washing particle 8a in the 1st filtration room 4a 15 mass% is preferred and 20 mass% is more preferred.
  • the upper limit of the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a is preferably 50% by mass, and more preferably 45% by mass. When the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a is less than the lower limit, there is a possibility that the cleaning of the first filtration particles 7a cannot be sufficiently promoted during backwashing.
  • the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a exceeds the above upper limit, the first filtration chamber 4a needs to be enlarged, so that the downflow type filtration tower is unnecessarily large. There is a risk.
  • the lower limit of the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b is preferably 10% by mass, and more preferably 15% by mass.
  • the upper limit of the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b is preferably 45 mass%, more preferably 40 mass%.
  • the lower limit of the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c is preferably 5% by mass, and more preferably 10% by mass.
  • the upper limit of the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c is preferably 40% by mass, and more preferably 35% by mass.
  • the lower limit of the average height of the head spaces 9a, 9b, 9c is the average height of the filtration chambers 4a, 4b, 4c (the average of the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c). 30% of the interval) is preferable, and 50% is more preferable.
  • an upper limit of the average height of the head spaces 9a, 9b, 9c 80% of the average height of the filtration chambers 4a, 4b, 4c is preferable, and 70% is more preferable.
  • the water treatment method using the downward flow type filtration tower in FIG. 1 includes a filtration step of filtering the liquid to be treated in the filtration chambers 4a, 4b, 4c, and filtration particles 7a, 7b, 7c in the filtration chambers 4a, 4b, 4c. And a filtration layer forming step of forming layers of filtration particles 7a, 7b, 7c in the filtration chambers 4a, 4b, 4c are repeated.
  • the liquid to be processed is supplied from the liquid supply path 5 to be processed, and the processed liquid obtained by filtering the liquid to be processed is discharged from the liquid discharge path 6 for processed liquid.
  • layers of cleaning particles 8a, 8b, 8c are formed on the lower partition plates 3a, 3b, 3c in the filtration chambers 4a, 4b, 4c, and layers of cleaning particles 8a, 8b, 8c are formed.
  • a filtration layer is formed by filtration particles 7a, 7b, and 7c on the top, and head spaces 9a, 9b, and 9c are formed between the filtration layer and the upper partition plates 2a, 2b, and 2c.
  • the supply method of the liquid to be treated is not particularly limited, and for example, a method such as pumping by a pump or natural flow by a water head can be used.
  • the lower limit of the supply amount of the liquid to be treated per unit cross-sectional area of the downward flow filtration tower in the water treatment method using the downward flow filtration tower is preferably 100 m 3 / m 2 ⁇ day, and 300 m 3 / m. 2 ⁇ day is more preferable.
  • the upper limit of the feed rate of the liquid to be treated is not particularly limited, but is preferably 3000m 3 / m 2 ⁇ day, more preferably 1000m 3 / m 2 ⁇ day.
  • the supply amount of the liquid to be processed is less than the lower limit, there is a risk that the processing capacity may be insufficient in an environment where a large amount of liquid to be processed is generated, or a large number of downflow filtration towers may be required.
  • the supply amount of the liquid to be treated exceeds the upper limit, the frequency of the backwashing process is increased, which may be inefficient.
  • the upper limit of the turbidity concentration of the treated liquid recovered by the water treatment method using the downward flow filtration tower in FIG. 1 is preferably 10 ppm, more preferably 5 ppm, further preferably 3 ppm, and particularly preferably 1 ppm.
  • turbidity concentration means the concentration of suspended solids (SS), and is a value measured according to “14.1 suspended matter” of JIS-K0102 (2008).
  • the upper limit of the oil concentration of the treated liquid recovered by the water treatment method using the downward flow filtration tower in FIG. 1 is preferably 100 ppm, more preferably 10 ppm, and even more preferably 1 ppm. If the oil concentration of the treated liquid exceeds the above upper limit, the load of the oil / water separation treatment downstream of the downflow filtration tower may be excessive, or the treated liquid can be discarded without causing any environmental load. There is a risk of disappearing.
  • washing water is supplied from the treated liquid discharge flow path 6, passes through the filtration chambers 4a, 4b, and 4c, and the oil and turbidity separated from the filtration particles 7a, 7b, and 7c, and the filtration chamber 4a, Washing wastewater containing oil and turbidity remaining in the space in the cylindrical main body 1 and the head spaces 9a, 9b, 9c of 4b, 4c is discharged from the liquid supply passage 5 to be treated.
  • this washing waste water may be supplied to the liquid to be processed supply channel 5 as a part of the liquid to be processed in the next filtration step.
  • the washing water flowing from the bottom to the top first causes the washing particles to rise, breaks the layers of the filtration particles 7a, 7b, and 7c solidified by oil and turbidity, and the filtration particles 7a, 7b, and 7c become the headspace by the washing water.
  • 9a, 9b, 9c can be raised.
  • the filtered particles 7a, 7b, and 7c raised in the head spaces 9a, 9b, and 9c are agitated in the washing water, and the attached oil and turbidity are peeled off. Further, the raised filter particles 7a, 7b, 7c collide with the other filter particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c, thereby promoting the separation of the attached oil and turbidity. .
  • the backwashing step may be performed at regular intervals.
  • the pressure difference between the liquid supply channel 5 to be processed and the liquid discharge channel 6 to be processed reaches a constant pressure in the filtration step, It may be performed when the flow rate of the processing liquid supply flow path 5 or the processed liquid discharge flow path 6 is reduced to a constant flow rate, or may be performed by operating an operator.
  • the amount of wash water supplied per unit cross-sectional area of the downward flow filtration tower can be, for example, 200 L / m 2 ⁇ hr or more and 2000 L / m 2 ⁇ hr or less.
  • the backwash time can be, for example, 30 seconds to 10 minutes.
  • an interval of backwashing when backwashing is performed every predetermined time it can be set to 1 hour or more and 12 hours or less, for example.
  • the washing water is preferably supplied as a bubbling jet water stream in which bubbles are mixed.
  • the bubbling jet water stream can be produced using, for example, a bubbling jet device, an eductor, or the like.
  • a bubbling jet water stream it is possible to promote separation of oil and turbidity from the filtered particles 7a, 7b, and 7c by bubbles.
  • the washing water may be supplied as a jet water stream that does not contain bubbles.
  • the amount of air in the bubbling jet water flow is preferably, for example, from 1 NL / L to 5 NL / L. Moreover, as an average diameter of the bubble in a bubbling jet water flow, 1 mm or more and 4 mm or less are preferable. Further, the feed pressure of the washing water is preferably 0.2 MPa or more, and the flow rate of the bubbling jet water flow is preferably 20 m / s or more at the outlet of the bubbling jet nozzle, for example.
  • ⁇ Filter layer forming step> the filtration chambers 4a, 4b and 4c are filled with water, and the filtration particles 7a, 7b and 7c and the washing particles 8a, 8b and 8c are naturally settled.
  • the cleaning particles 8a, 8b, and 8c having a large average specific gravity and a large average particle diameter have a high sedimentation speed, and settle first to form a layer on the lower partition plates 3a, 3b, and 3c.
  • Filter particles 7a, 7b, and 7c having a smaller average specific gravity and average particle diameter and lower settling velocity than cleaning particles 8a, 8b, and 8c are deposited on the previously formed layer of cleaning particles 8a, 8b, and 8c.
  • a filtration layer is formed.
  • water containing no air is supplied from the treated liquid discharge flow path 6 at a flow rate that is equal to or higher than the flow rate of the washing water in the backwashing step. If the inside of 4c is filled with water and the filtering particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c are pressed against the upper partition plates 2a, 2b, 2c, the cleaning particles 8a, 8b, 8c and the filtering particles 7a , 7b, 7c can be promoted.
  • the downflow filtration tower includes a plurality of filtration chambers 4a, 4b, and 4c filled with filtration particles 7a, 7b, and 7c and cleaning particles 8a, 8b, and 8c. Since the upper filtration chamber with a higher concentration of oil and turbidity has a higher sedimentation rate of the cleaning particles because it is filled with cleaning particles having a higher average specific gravity, the upper filtration chamber has a larger particle size and a larger sedimentation rate. Particles can be used. That is, the downflow type filtration tower increases the average particle size of the filtration particles in the upper filtration chamber so that clogging is less likely to occur, and decreases the average particle size of the filtration particles in the lower side. Small oil and turbidity can be removed. In addition, since the downflow type filtration tower is filled with cleaning particles in each filtration chamber, the filter particles are quickly washed by breaking the layer of filter particles solidified with oil or turbidity by the washing particles during backwashing. be able to.
  • the number of filtration chambers disposed in the downward flow filtration tower is not particularly limited, and can be any number of 2 or more.
  • the filtration chamber may be used in combination with a unit having an adsorbent for oil such as porous ceramics, woven fabric, non-woven fabric, fiber, activated carbon or the like.
  • the oil adsorbent unit is preferably disposed downstream of the filtration chamber.
  • the filtration chamber may be one in which no head space is formed on the filtration particles and the washing particles.
  • a plurality of water supply passages for supplying washing water to the lower side of each filtration chamber may be provided on the side of the cylindrical body, and a plurality of drainage channels for discharging washing wastewater from above each filtration chamber are provided. May be.
  • the water supply path for supplying the cleaning water to the lower side of the filtration chamber may have a nozzle that discharges the cleaning water toward the lower surface of the lower partition plate. By providing such a nozzle, a flow having a high flow velocity can be formed at least partially in the filtration chamber, and the effect of breaking the layer of filtration particles with the cleaning particles can be promoted.
  • the nozzle may be disposed so as to be buried in a layer of filtration particles or cleaning particles, and a layer of filtration particles or cleaning particles may be broken by directly acting the water pressure of the cleaning water.
  • cleaning water may be supplied from the side to the position of the head space formed in the steady state.
  • the scrubbing effect of the filtered particles can be promoted by the washing water supplied to the position of the head space of the filtration chamber and having a flow in a direction different from the washing water from below.
  • the flow path for supplying cleaning water into the filtration chamber may include a nozzle that protrudes into the filtration chamber and opens downward. By providing such a nozzle, it is possible to promote the cleaning effect of the filtered particles by forming a downward flow, and to make the filtered particle layer break up by colliding with the cleaning particle having a large flow velocity against the filtered particle layer. it can.
  • the downflow filtration tower can be suitably used for removing oil and turbidity from the liquid to be treated generated in oil fields and factories.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Materials (AREA)

Abstract

The purpose of the present invention is to provide a filtration tower that can remove a fine oil component and suspended matter and that is excellent in terms of the cleaning performance of filtering particles. This filtration tower is a downflow-type filtration tower that is provided with a plurality of filtration chambers that are partitioned from each other by a plurality of water-permeable partition plates. Each of the plurality of filtration chambers is filled with filtering particles and cleaning particles. The average particle diameter and the average specific gravity of the cleaning particles of each filtration chamber are larger than those of the cleaning particles of the filtration chamber immediately below. It is preferable that the average particle diameter of the cleaning particles of each filtration chamber be 1.5 times or more and 10 times or less the average particle diameter of the cleaning particles of the filtration chamber immediately below. It is preferable that the average specific gravity of the cleaning particles of each filtration chamber be 1.1 times or more and 2 times or less the average specific gravity of the cleaning particles of the filtration chamber immediately below. The filled mass ratio of the cleaning particles of each filtration chamber is preferably larger than the filled mass ratio of the cleaning particles of the filtration chamber immediately below.

Description

下向流式濾過塔Downflow filter tower
　本発明は、下向流式濾過塔に関する。 The present invention relates to a downflow filter tower.
　油田や工場等で発生する油分や濁質を含んだ油水混合液は、環境保全の観点から油分や濁質の混合量を一定値以下まで低減してから廃棄する必要がある。油分や濁質を混合液から分離除去する方法としては、重力分離、蒸留分離、薬品分離等があるが、低コストで油分や濁質を分離除去する方法として濾過粒子を封入した濾過塔を用いる方法がある。このような濾過塔では、封入した濾過粒子によって形成される濾過層により油分や濁質を濾過する。 Oil / water mixtures containing oil and turbidity generated in oil fields and factories need to be discarded after the amount of oil and turbidity is reduced to a certain value or less from the viewpoint of environmental conservation. There are gravity separation, distillation separation, chemical separation, etc. as a method for separating and removing oil and turbidity from the liquid mixture. As a method for separating and removing oil and turbidity at a low cost, a filtration tower containing filtration particles is used. There is a way. In such a filtration tower, oil and turbidity are filtered by a filtration layer formed by enclosed filtration particles.
　上記濾過塔は、濾過粒子に油分や濁質が付着することにより、濁質の分離が不十分となったり、通水量が減少したりする。このため、濾過塔に、上流側ほど濾過粒子の隙間が大きくなるよう複数種類の濾過粒子を層分けして充填することにより、局所的に濾過粒子が目詰まりすることを抑制する方法が知られている（例えば特開２０１３－２４８５６３号公報参照）。 In the above filtration tower, oil or turbidity adheres to the filter particles, resulting in insufficient separation of turbidity or reduced water flow rate. For this reason, a method is known in which filtration particles are locally blocked by clogging the filtration tower with a plurality of types of filtration particles so that the gap between the filtration particles increases toward the upstream side. (For example, refer to JP2013-248563A).
　また、濾過塔において濾過粒子が目詰まりした場合、あるいは目詰まりを予防するために一定時間毎に、濾過塔に通常の通水方向とは逆向きに洗浄水を通水し、濾過粒子に付着した油分や濁質を除去する洗浄工程、いわゆる逆洗が行われる。 In addition, when the filter particles are clogged in the filter tower or in order to prevent clogging, wash water is passed through the filter tower in the direction opposite to the normal water flow direction to adhere to the filter particles. A washing process for removing the oil and turbidity, so-called back washing is performed.
　上記公報には、上記逆洗を効率よく行うために、比重の異なる濾過粒子を充填し、逆洗時にこれらの粒子が撹拌されて互いにもみ洗い状態となることで、濾過粒子の逆洗を効率化することが提案されている。 In the above publication, in order to perform the backwashing efficiently, the filtration particles having different specific gravities are filled, and these particles are agitated at the time of backwashing so that they can be washed with each other. It has been proposed to
　上記公報の濾過塔では、逆洗終了時に、濾過粒子の沈降速度の違いによって濾過粒子の層分けを行う。このため、粒子間の隙間が大きくなる濾過粒子の沈降速度が、粒子間の隙間が小さくなる濾過粒子の沈降速度よりも小さくなければならない。そこで、上記公報には、上層を形成する濾過粒子として比重が小さい樹脂繊維濾材を用い、下層を形成する濾過粒子として比重が大きいポーラスセラミックス濾材を用いることを提案している。 In the filtration tower of the above publication, at the end of backwashing, the filtration particles are divided into layers according to the difference in sedimentation speed of the filtration particles. For this reason, the sedimentation rate of the filtration particles in which the gaps between the particles are large must be smaller than the sedimentation rate of the filtration particles in which the gaps between the particles are small. Therefore, the above publication proposes using a resin fiber filter medium having a small specific gravity as the filter particles forming the upper layer and using a porous ceramic filter medium having a large specific gravity as the filter particles forming the lower layer.
　一般に、粒状物は、粒径が大きいほど沈降速度が大きくなる。従って、沈降速度の違いにより層分けしようとすると下層の方が粒子間の隙間が大きくなり易いため、下層において微細な濁質等を捕捉することができないおそれがある。このため、上記公報の構成では、樹脂繊維濾材とポーラスセラミックス濾材との組み合わせにより沈降速度の差を確保している。 Generally, the sedimentation rate of granular materials increases as the particle size increases. Accordingly, when trying to stratify due to the difference in sedimentation speed, the gap between particles tends to be larger in the lower layer, and there is a possibility that fine turbidity or the like cannot be captured in the lower layer. For this reason, in the structure of the said gazette, the difference of the sedimentation rate is ensured by the combination of the resin fiber filter medium and the porous ceramics filter medium.
特開２０１３－２４８５６３号公報JP 2013-248563 A
　しかしながら、ポーラスセラミックス濾材の粒径を小さくするには限界があり、上記公報に記載の濾過塔では、微細な油分や濁質を除去することが容易ではないという不都合がある。 However, there is a limit to reducing the particle size of the porous ceramic filter medium, and the filtration tower described in the above publication has the disadvantage that it is not easy to remove fine oil and turbidity.
　本発明は、上述のような事情に基づいてなされたものであり、微細な油分や濁質を除去できると共に、濾過粒子の洗浄性能に優れる濾過塔を提供することを課題とする。 The present invention has been made based on the above-described circumstances, and an object of the present invention is to provide a filtration tower that can remove fine oil and turbidity and is excellent in the washing performance of filtration particles.
　上記課題を解決するためになされた本発明の一態様に係る濾過塔は、複数の通水性の仕切板で区画される複数の濾過室を備える下向流式濾過塔であって、上記複数の濾過室それぞれに濾過粒子と洗浄粒子とが充填され、上記濾過室の洗浄粒子の平均粒径及び平均比重がその濾過室直下の濾過室の洗浄粒子よりも大きい。 A filtration tower according to an aspect of the present invention made to solve the above problems is a downward flow filtration tower including a plurality of filtration chambers partitioned by a plurality of water-permeable partition plates. Each filtration chamber is filled with filtration particles and washing particles, and the average particle size and average specific gravity of the washing particles in the filtration chamber are larger than the washing particles in the filtration chamber immediately below the filtration chamber.
　本発明の一態様に係る下向流式濾過塔は、微細な油分や濁質を除去できると共に、濾過粒子の洗浄性能に優れる。 The downflow filter tower according to one embodiment of the present invention can remove fine oil and turbidity and is excellent in cleaning performance of the filter particles.
図１は、本発明の一実施形態の下向流式濾過塔を示す模式的断面図である。FIG. 1 is a schematic cross-sectional view showing a downflow filtration tower according to an embodiment of the present invention.
［本発明の実施形態の説明］
　本発明の一態様に係る濾過塔は、複数の通水性の仕切板で区画される複数の濾過室を備える下向流式濾過塔であって、上記複数の濾過室それぞれに濾過粒子と洗浄粒子とが充填され、上記濾過室の洗浄粒子の平均粒径及び平均比重がその濾過室直下の濾過室の洗浄粒子よりも大きい(但し、最下段の濾過室は除く)。 [Description of Embodiment of the Present Invention]
A filtration tower according to an aspect of the present invention is a downward flow filtration tower including a plurality of filtration chambers partitioned by a plurality of water-permeable partition plates, and each of the plurality of filtration chambers includes filtration particles and cleaning particles. The average particle size and average specific gravity of the cleaning particles in the filtration chamber are larger than the cleaning particles in the filtration chamber immediately below the filtration chamber (except for the lowermost filtration chamber).
　当該下向流式濾過塔は、濾過粒子と洗浄粒子とが充填される複数の濾過室を備えることによって、逆洗時に各濾過室内で油分や濁質で固まった濾過粒子の層を洗浄粒子により割りほぐすことで濾過粒子の洗浄効果を促進できる。また、当該下向流式濾過塔では、上側の濾過室ほど平均粒径及び平均比重が大きい洗浄粒子が充填されていることによって、上側の濾過室ほど洗浄粒子の沈降速度が大きい。これにより、上側の濾過室ほど粒径が大きく沈降速度が大きい濾過粒子を使用することが可能となる。つまり、上側の濾過室ほど濾過粒子の平均粒径を大きくして目詰まりを起こし難くすると共に、下側ほど濾過粒子の平均粒径を小さくしてより小さい油分や濁質を取り除くことができる。また、当該下向流式濾過塔は、各濾過室にそれぞれ洗浄粒子が充填されるので、逆洗によって各濾過粒子をより迅速に洗浄することができる。 The down-flow type filtration tower includes a plurality of filtration chambers filled with filtration particles and washing particles, so that a layer of filtration particles solidified with oil or turbidity in each filtration chamber during backwashing can be obtained by washing particles. The cleaning effect of the filtration particles can be promoted by splitting. In the downflow type filtration tower, the upper filtration chamber is filled with cleaning particles having a larger average particle diameter and average specific gravity, so that the upper filtration chamber has a higher settling rate of the cleaning particles. Thereby, it becomes possible to use filtration particles having a larger particle size and a higher sedimentation rate in the upper filtration chamber. That is, it is possible to make the average particle size of the filtration particles larger in the upper filtration chamber so that clogging is less likely to occur, and to reduce the average particle size of the filtration particles toward the lower side to remove smaller oil and turbidity. Moreover, since each said filtration chamber is each filled with washing | cleaning particle | grains, the said downward flow type filtration tower can wash | clean each filtration particle | grain more rapidly by backwashing.
　上記濾過室の洗浄粒子の平均粒径としては、その濾過室直下の濾過室の洗浄粒子の平均粒径の１．５倍以上１０倍以下が好ましい。このように、隣接する濾過室間の洗浄粒子の平均粒径の比を上記範囲内とすることによって、各濾過室の濾過粒子の平均粒径、平均比重等の選択による目詰まりの回避と濾過能力の向上とがより確実になる。 The average particle size of the cleaning particles in the filtration chamber is preferably 1.5 to 10 times the average particle size of the cleaning particles immediately below the filtration chamber. Thus, by setting the ratio of the average particle size of the cleaning particles between adjacent filtration chambers within the above range, clogging can be avoided and filtered by selecting the average particle size, average specific gravity, etc. of the filtration particles in each filtration chamber. The improvement of ability is more certain.
　上記濾過室の洗浄粒子の平均比重としては、その濾過室直下の濾過室の洗浄粒子の平均比重の１．１倍以上２倍以下が好ましい。このように、隣接する濾過室間の洗浄粒子の平均比重の比を上記範囲内とすることによって、各濾過室の濾過粒子の平均粒径、平均比重等の選択による目詰まりの回避と濾過能力の向上とがさらに確実になる。 The average specific gravity of the cleaning particles in the filtration chamber is preferably 1.1 to 2 times the average specific gravity of the cleaning particles in the filtration chamber immediately below the filtration chamber. In this way, by setting the ratio of the average specific gravity of the cleaning particles between adjacent filtration chambers within the above range, clogging can be avoided and filtration capacity can be selected by selecting the average particle size, average specific gravity, etc. of the filtration particles in each filtration chamber. The improvement is further ensured.
　上記濾過室の洗浄粒子の充填質量割合が、その濾過室直下の濾過室の洗浄粒子の充填質量割合よりも大きいとよい。このように、上側ほど洗浄粒子の充填質量割合を大きくすることによって、汚れが大きくなり易い上側の濾過粒子を効率よく洗浄できると共に、下側の濾過室を小さくして濾過塔を小型化できる。 The filling mass ratio of the cleaning particles in the filtration chamber is preferably larger than the filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber. Thus, by increasing the filling mass ratio of the cleaning particles toward the upper side, it is possible to efficiently clean the upper filtration particles that are likely to become dirty, and to reduce the size of the lower filtration chamber and to reduce the size of the filtration tower.
　上記濾過室中の洗浄粒子の充填質量割合とその濾過室直下の濾過室の洗浄粒子の充填質量割合との差としては、５％以上２０％以下が好ましい。このように、隣接する濾過室間の洗浄粒子の充填質量割合の差を上記範囲内とすることによって、濾過粒子の洗浄性能を向上しながら、濾過室の容積の増大を抑制できる。 The difference between the filling mass ratio of the cleaning particles in the filtration chamber and the filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber is preferably 5% or more and 20% or less. Thus, by making the difference of the filling mass ratio of the cleaning particles between the adjacent filtration chambers within the above range, it is possible to suppress the increase in the volume of the filtration chamber while improving the cleaning performance of the filtration particles.
　１の濾過室の上記洗浄粒子の平均粒径及び平均比重が同じ濾過室の濾過粒子よりも大きいとよい。このように、各濾過室において洗浄粒子の平均粒径及び平均比重を濾過粒子よりも大きくすることによって、沈降速度の差により下側の洗浄粒子の層と上側の濾過粒子の層とを効率よく層分けできる。その結果、油分や濁質の除去が阻害されない。 The average particle size and average specific gravity of the cleaning particles in one filtration chamber may be larger than the filtration particles in the same filtration chamber. In this way, by making the average particle diameter and average specific gravity of the cleaning particles larger than that of the filtering particles in each filtering chamber, the lower cleaning particle layer and the upper filtering particle layer are efficiently separated due to the difference in sedimentation speed. Can be stratified. As a result, the removal of oil and turbidity is not hindered.
　ここで、「平均粒径」とは、ＪＩＳ－Ｚ８８０１－１（２００６）に規定される篩を用い、目開きの大きい篩から順に篩分けて目開きを通過する粒子の質量割合を測定し、公称目開きを粒径として作成される粒径分布において積算質量が５０％となる値（ｄ５０）を意味する。「平均比重」とは、ＪＩＳ－Ｚ８８０７（２０１２）に準拠して測定される値である。また、「濁質」とは、油分を除く懸濁物質を意味する。なお、「油分」と「濁質」とが分離されている必要はなく、エマルジョンを形成していてもよい。また、洗浄粒子の「充填質量割合」とは、各濾過室内に充填される濾過粒子及び洗浄粒子の合計質量に対する洗浄粒子の質量の割合を意味する。 Here, the “average particle diameter” is a sieve defined in JIS-Z8801-1 (2006), and sieved in order from a sieve having a large mesh size, and the mass ratio of particles passing through the mesh is measured. It means a value (d50) at which the integrated mass becomes 50% in the particle size distribution created with the nominal aperture as the particle size. “Average specific gravity” is a value measured in accordance with JIS-Z8807 (2012). The “turbidity” means a suspended substance excluding oil. The “oil” and “turbidity” do not have to be separated, and an emulsion may be formed. Further, the “filling mass ratio” of the cleaning particles means the ratio of the mass of the cleaning particles to the total mass of the filtering particles and the cleaning particles filled in each filtration chamber.
［本発明の実施形態の詳細］
　以下、本発明の一実施形態の下向流式濾過塔について図面を参照しつつ詳説する。 [Details of the embodiment of the present invention]
Hereinafter, a downward flow filter tower according to an embodiment of the present invention will be described in detail with reference to the drawings.
［下向流式濾過塔］
　図１の下向流式濾過塔は、被処理液を上から下に通過させて濾過する装置である。この下向流式濾過塔によって濾過する被処理液としては、典型的には油分と濁質とを含有する石油随伴水が挙げられる。この濁質とは、例えば砂、シリカや炭酸カルシウムなどの粒子、鉄粉、微生物、木片等を含む。 [Downward flow filtration tower]
The downflow type filtration tower in FIG. 1 is a device that filters the liquid to be treated from the top to the bottom. The liquid to be treated to be filtered by the downflow type filtration tower typically includes petroleum-associated water containing oil and turbidity. The turbidity includes, for example, particles such as sand, silica and calcium carbonate, iron powder, microorganisms, and wood chips.
　当該下向流式濾過塔は、中心軸が鉛直方向と略一致するよう立設され、天板部及び底板部を有する筒状本体１と、この筒状本体１に略水平に配設され、筒状本体１の内部空間を区画する通水性の第１乃至第３の上側仕切板２ａ，２ｂ，２ｃと、これら上側仕切板２ａ，２ｂ，２ｃと対をなし、筒状本体１の内部空間を区画する通水性の第１乃至第３の下側仕切板３ａ，３ｂ，３ｃとを備える。 The downflow type filtration tower is erected so that the center axis substantially coincides with the vertical direction, and is disposed substantially horizontally on the tubular body 1 having a top plate portion and a bottom plate portion, and the tubular body 1, A pair of water-permeable first to third upper partition plates 2a, 2b, and 2c partitioning the inner space of the cylindrical main body 1 and the upper partition plates 2a, 2b, and 2c, and the inner space of the cylindrical main body 1 Permeable first to third lower partition plates 3a, 3b, 3c.
　これにより、当該下向流式濾過塔は、筒状本体１の内部に、上側から順に、第１上側仕切板２ａと第１下側仕切板３ａとの間に第１濾過室４ａが画定され、第２上側仕切板２ｂと第２下側仕切板３ｂとの間に第２濾過室４ｂが画定され、第３上側仕切板２ｃと第３下側仕切板３ｃとの間に第３濾過室４ｃが画定される。 Thus, in the downward flow filtration tower, the first filtration chamber 4a is defined in the cylindrical main body 1 between the first upper partition plate 2a and the first lower partition plate 3a in order from the upper side. A second filtration chamber 4b is defined between the second upper partition plate 2b and the second lower partition plate 3b, and a third filtration chamber is disposed between the third upper partition plate 2c and the third lower partition plate 3c. 4c is defined.
　当該下向流式濾過塔は、筒状本体１にその上端から上記被処理液を供給する被処理液供給流路５と、筒状本体１の内部での被処理液の濾過により得られる処理済液を筒状本体１の下端から排出する処理済液排出流路６とをさらに有する。 The downflow type filtration tower is a treatment liquid supply channel 5 for supplying the liquid to be treated to the cylindrical main body 1 from its upper end, and a treatment obtained by filtration of the liquid to be treated inside the cylindrical main body 1. A treated liquid discharge channel 6 for discharging the finished liquid from the lower end of the cylindrical main body 1 is further provided.
　筒状本体１の内部に画定される第１濾過室４ａには、第１濾過粒子７ａとこの第１濾過粒子７ａよりも平均粒径及び平均比重が大きい第１洗浄粒子８ａとが充填されている。また、第１濾過室４ａは、定常状態（連続的に濾過を行っている状態）で第１濾過粒子７ａ及び第１洗浄粒子８ａの上方に第１ヘッドスペース９ａを有する。 The first filtration chamber 4a defined inside the cylindrical body 1 is filled with the first filtration particles 7a and the first cleaning particles 8a having an average particle size and an average specific gravity larger than the first filtration particles 7a. Yes. Moreover, the 1st filtration chamber 4a has the 1st head space 9a above the 1st filtration particle | grains 7a and the 1st washing | cleaning particle 8a in the steady state (state which filters continuously).
　同様に、第２濾過室４ｂには、第２濾過粒子７ｂとこの第２濾過粒子７ｂよりも平均粒径及び平均比重が大きい第２洗浄粒子８ｂとが充填されている。また、第２濾過室４ｂは、定常状態（連続的に濾過を行っている状態）で第２濾過粒子７ｂ及び第２洗浄粒子８ｂの上方に第２ヘッドスペース９ｂを有する。 Similarly, the second filtration chamber 4b is filled with the second filtration particles 7b and the second cleaning particles 8b having an average particle diameter and an average specific gravity larger than those of the second filtration particles 7b. The second filtration chamber 4b has a second head space 9b above the second filtration particles 7b and the second cleaning particles 8b in a steady state (a state in which filtration is continuously performed).
　さらに、第３濾過室４ｃには、第３濾過粒子７ｃとこの第３濾過粒子７ｃよりも平均粒径及び平均比重が大きい第３洗浄粒子８ｃとが充填されている。また、第３濾過室４ｃは、定常状態（連続的に濾過を行っている状態）で第３濾過粒子７ｃ及び第３洗浄粒子８ｃの上方に第３ヘッドスペース９ｃを有する。 Furthermore, the third filtration chamber 4c is filled with third filtration particles 7c and third cleaning particles 8c having an average particle diameter and an average specific gravity larger than those of the third filtration particles 7c. The third filtration chamber 4c has a third head space 9c above the third filtration particles 7c and the third cleaning particles 8c in a steady state (a state in which filtration is continuously performed).
＜筒状本体＞
　筒状本体１は、金属や樹脂によって、内部に挿通する液体の圧力に耐える強度を有するよう形成される。筒状本体１を形成する材料としては、特に、強度、耐熱性、耐薬品性等の観点からステンレス、アクリロニトリル－ブタジエン－スチレン共重合体（ＡＢＳ樹脂）、ガラス繊維強化プラスチック又は炭素繊維強化プラスチックが好ましい。また、筒状本体１は、外側に補強部材や自立するための脚部材等が設けられてもよい。 <Cylindrical body>
The cylindrical main body 1 is formed of metal or resin so as to have a strength that can withstand the pressure of the liquid that is inserted into the cylindrical main body 1. Examples of the material for forming the cylindrical body 1 include stainless steel, acrylonitrile-butadiene-styrene copolymer (ABS resin), glass fiber reinforced plastic, or carbon fiber reinforced plastic from the viewpoint of strength, heat resistance, chemical resistance, and the like. preferable. Moreover, the cylindrical main body 1 may be provided with a reinforcing member or a leg member for self-standing on the outside.
　筒状本体１の平面形状としては、特に限定されず、例えば円形、楕円形、矩形等の任意の形状とすることができるが、一様な液体の流れを形成し易く、後述する濾過粒子及び洗浄粒子並びに油分及び濁質の詰まりや滞留を防止できることから、角のない形状が好ましく、典型的には円形とされる。また、筒状本体１の平面形状を角のない形状とすることは、筒状本体１の強度を得易く設計が容易となるメリットもある。筒状本体１の被処理液供給流路５が配設される天板部及び処理済液排出流路６が配設される底板部は、平板であってもよいが、耐圧性が得られる鏡板状とすることが好ましい。 The planar shape of the cylindrical main body 1 is not particularly limited, and may be any shape such as a circle, an ellipse, a rectangle, etc., but it is easy to form a uniform liquid flow. From the viewpoint of preventing clogging and staying of cleaning particles and oil and turbidity, a shape without corners is preferable, and a circular shape is typically used. Moreover, making the planar shape of the cylindrical main body 1 without a corner has an advantage that the strength of the cylindrical main body 1 can be easily obtained and the design can be facilitated. The top plate portion where the liquid supply flow path 5 to be processed and the bottom plate portion where the processed liquid discharge flow path 6 are arranged may be flat plates, but pressure resistance is obtained. It is preferable to use a mirror-plate shape.
　筒状本体１の大きさとしては、処理すべき被処理水の流量等に応じて選択され、特に限定されない。筒状本体１の平均断面積としては、例えば０．１ｍ２以上１０ｍ２以下とすることができる。また、筒状本体１の高さとしては、例えば０．５ｍ以上１０ｍ以下とすることができる。 The size of the cylindrical main body 1 is not particularly limited, and is selected according to the flow rate of water to be treated to be treated. The average cross-sectional area of the cylindrical main body 1 can be, for example, 0.1 m 2 or more 10 m 2 or less. Moreover, as the height of the cylindrical main body 1, it can be set to 0.5 m or more and 10 m or less, for example.
＜仕切板＞
　下側仕切板３ａ，３ｂ，３ｃ及び上側仕切板２ａ，２ｂ，２ｃは、水を通過させ、かつ濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃを通過させない板状の部材で形成される。これらの下側仕切板３ａ，３ｂ，３ｃ及び上側仕切板２ａ，２ｂ，２ｃは、濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃを濾過室４ａ，４ｂ，４ｃの内部に封止する機能を果たす。 <Partition plate>
The lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c are formed of plate-like members that allow water to pass therethrough and not allow the filtered particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c to pass therethrough. Is done. These lower partition plates 3a, 3b, 3c and upper partition plates 2a, 2b, 2c seal the filtration particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c inside the filtration chambers 4a, 4b, 4c. Fulfills the function of
　この下側仕切板３ａ，３ｂ，３ｃ及び上側仕切板２ａ，２ｂ，２ｃの具体的な材料としては、例えば気孔率の大きい多孔質板、多数の小孔が形成された板、ワイヤーメッシュ等が挙げられる。また、下側仕切板３ａ，３ｂ，３ｃ及び上側仕切板２ａ，２ｂ，２ｃは、目開きの大きい支持部材と、この支持部材の目を覆うよう配設された網状、織布状又は不織布状の部材との組み合わせからなってもよい。 Specific materials of the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c include, for example, a porous plate having a large porosity, a plate formed with a large number of small holes, a wire mesh, and the like. Can be mentioned. Further, the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c are a support member having a large mesh and a net-like, woven or non-woven fabric provided so as to cover the eyes of the support member. It may consist of a combination with these members.
　下側仕切板３ａ，３ｂ，３ｃ及び上側仕切板２ａ，２ｂ，２ｃの材質としては、特に限定されず、金属や合成樹脂等を用いることができる。金属を用いる場合、防食の観点から耐食性ステンレス鋼（例えばＳＵＳ３１６Ｌ等）を用いることが好ましい。板状の合成樹脂を用いる場合、水圧や粒子の重量によって目開きが変化しないよう補強ワイヤー等の支持部材を併用することが好ましい。ワイヤーメッシュを用いる場合、例えばステンレス鋼線、ケブラー繊維、カーボン繊維等の強度及び耐熱性に優れる線材からなるメッシュを使用することが好ましい。 The material of the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c is not particularly limited, and metal, synthetic resin, or the like can be used. When using a metal, it is preferable to use corrosion-resistant stainless steel (for example, SUS316L) from the viewpoint of corrosion prevention. When using a plate-shaped synthetic resin, it is preferable to use a support member such as a reinforcing wire in combination so that the opening is not changed by the water pressure or the weight of the particles. When using a wire mesh, it is preferable to use a mesh made of a wire material having excellent strength and heat resistance, such as stainless steel wire, Kevlar fiber, carbon fiber and the like.
　下側仕切板３ａ，３ｂ，３ｃ及び上側仕切板２ａ，２ｂ，２ｃをワイヤーメッシュで形成する場合、ワイヤーメッシュの公称目開きは、対応する濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃの最小粒径以下となるよう設計されることが好ましい。また、濾過粒子７ａ，７ｂ，７ｃ又は洗浄粒子８ａ，８ｂ，８ｃの最小粒径が微小である場合、ワイヤーメッシュの目開きをそれよりも小さくすると差圧が大きくなり過ぎるおそれがある。このため、ワイヤーメッシュの公称目開きは、対応する濾過粒子７ａ，７ｂ，７ｃの平均粒径から対応する濾過粒子７ａ，７ｂ，７ｃの粒径の標準偏差を引いた値以下とすることが好ましい。 When the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c are formed of wire mesh, the nominal mesh openings of the wire mesh are the corresponding filtration particles 7a, 7b, 7c and cleaning particles 8a, 8b, It is preferably designed to be less than the minimum particle size of 8c. Moreover, when the minimum particle diameter of the filtration particles 7a, 7b, 7c or the cleaning particles 8a, 8b, 8c is very small, if the opening of the wire mesh is made smaller than that, the differential pressure may become too large. For this reason, it is preferable that the nominal mesh opening of the wire mesh is not more than a value obtained by subtracting the standard deviation of the particle diameters of the corresponding filtration particles 7a, 7b, 7c from the average particle diameter of the corresponding filtration particles 7a, 7b, 7c. .
（濾過粒子）
　濾過粒子７ａ，７ｂ，７ｃは、被処理水を濾過する層を形成する濾材である。この濾過粒子７ａ，７ｂ，７ｃとしては、公知の濾過処理用の粒子を用いることができ、例えば天然砂、無機物粒子、セラミックス、ポリマー（高分子化合物）、天然有機素材等を主成分とする粒子を用いることができる。 (Filtered particles)
The filtration particles 7a, 7b, and 7c are filter media that form a layer for filtering the water to be treated. As the filtration particles 7a, 7b, 7c, known filtration particles can be used, for example, particles mainly composed of natural sand, inorganic particles, ceramics, polymers (polymer compounds), natural organic materials, and the like. Can be used.
　ただし、濾過粒子７ａ，７ｂ，７ｃは、ポリマーを主成分とすることが好ましい。濾過粒子７ａ，７ｂ，７ｃをポリマーを主成分とするものとすることによって、濾過室４ａ，４ｂ，４ｃのコスト及び重量を低減することができる。また、ポリマーを用いることにより、濾過粒子７ａ，７ｂ，７ｃの比重を小さくできるため、逆洗時の撹拌作用による濾過粒子７ａ，７ｂ，７ｃの洗浄促進効果をさらに高めることができる。 However, it is preferable that the filtration particles 7a, 7b, and 7c have a polymer as a main component. By making the filtration particles 7a, 7b, and 7c a polymer as a main component, the cost and weight of the filtration chambers 4a, 4b, and 4c can be reduced. Moreover, since the specific gravity of filtration particle | grains 7a, 7b, 7c can be made small by using a polymer, the washing | cleaning promotion effect of filtration particle | grains 7a, 7b, 7c by the stirring action at the time of backwashing can further be heightened.
　濾過粒子７ａ，７ｂ，７ｃの主成分とされるポリマーとしては、例えばフッ素樹脂、ビニル樹脂、ポリオレフィン、ポリウレタン、エポキシ樹脂、アクリル樹脂、ポリエステル、ポリアミド、ポリイミド、メラミン樹脂、ポリカーボネート等を挙げることができる。
これらの中でも耐水性、耐油性等に優れるフッ素樹脂、ビニル樹脂、ポリウレタン、エポキシ樹脂及びアクリル樹脂が好ましく、耐食性に優れるフッ素樹脂及び吸着性に優れるポリオレフィンがより好ましい。さらに、ポリオレフィンの中では、特に油分吸着能力に優れるポリプロピレンが好ましい。また、フッ素樹脂は、強度、耐熱性及び耐薬品性に優れ、かつ比較的比重が大きいので洗浄後に沈降が早く、早く濾過を再開できるというメリットがある。なお、濾過粒子７ａ，７ｂ，７ｃの材質は、濾過室毎に異なっていてもよく、それぞれ複数種類の粒子を含んでもよい。 Examples of the polymer as the main component of the filtration particles 7a, 7b, and 7c include a fluororesin, a vinyl resin, a polyolefin, a polyurethane, an epoxy resin, an acrylic resin, a polyester, a polyamide, a polyimide, a melamine resin, and a polycarbonate. .
Among these, a fluororesin, a vinyl resin, a polyurethane, an epoxy resin, and an acrylic resin excellent in water resistance and oil resistance are preferable, and a fluororesin excellent in corrosion resistance and a polyolefin excellent in adsorptivity are more preferable. Further, among polyolefins, polypropylene that is particularly excellent in oil adsorption capacity is preferable. In addition, the fluororesin is excellent in strength, heat resistance, and chemical resistance, and has a relatively large specific gravity, so that it has a merit that it can settle quickly after washing and can be quickly filtered. In addition, the material of filtration particle | grains 7a, 7b, 7c may differ for every filtration chamber, and may contain multiple types of particle | grains, respectively.
　また、上記天然砂としては、例えばアンスラサイト、ガーネット、マンガン砂等を挙げることができ、これらを１種で又は２種以上混合して用いることができる。上記セラミックスとしては、例えばシリカ、アルミナ、ガラス等を主成分とするセラミックス粒子を用いることができる。上記天然有機素材としては、天然の有機物を篩い分けして粒子サイズを整えたものを使用することができ、例えばクルミの殻、おがくず、麻などの天然繊維等を挙げることができる。 Moreover, examples of the natural sand include anthracite, garnet, manganese sand, and the like, and these can be used alone or in combination of two or more. As the ceramic, for example, ceramic particles mainly composed of silica, alumina, glass or the like can be used. As the natural organic material, a natural organic material having a particle size adjusted by sieving can be used, and examples thereof include natural fibers such as walnut shell, sawdust and hemp.
　また、上記無機物粒子としては、粒径及び比重が揃ったものを比較的容易に入手できる点でガラスビーズが好ましい。特に好ましいガラスビーズとしては、例えばアルミナを含有する球状ガラスビーズを挙げることができる。このようなガラスビーズは、油の付着によっても塊に成長し難く、洗浄時に分散して流動し易いという長所を有する。従って、このようなガラスビーズの使用により安定した濾過性能と高い洗浄効果とを得ることができる。 Further, as the inorganic particles, glass beads are preferable in that particles having a uniform particle size and specific gravity can be obtained relatively easily. Particularly preferable glass beads include, for example, spherical glass beads containing alumina. Such glass beads have an advantage that they are difficult to grow into a lump even when oil adheres, and are easy to disperse and flow during washing. Therefore, stable filtration performance and high cleaning effect can be obtained by using such glass beads.
　濾過粒子７ａ，７ｂ，７ｃの形状としては、特に限定されず、例えば球形、柱形等任意の形状とすることができる。特に、濾過粒子７ａ，７ｂ，７ｃとして、不定形の粉砕粒子を用いることで、濾過粒子７ａ，７ｂ，７ｃを緻密に堆積させることができ、濾過効率を向上させると共に、定常状態における濾過粒子７ａ，７ｂ，７ｃの浮き上がりを防止することができる。 The shape of the filtration particles 7a, 7b, and 7c is not particularly limited, and may be any shape such as a spherical shape or a column shape. In particular, by using irregularly pulverized particles as the filtration particles 7a, 7b, and 7c, the filtration particles 7a, 7b, and 7c can be densely deposited, and the filtration efficiency is improved and the filtration particles 7a in a steady state. , 7b, 7c can be prevented.
　濾過粒子７ａ，７ｂ，７ｃの平均粒径は、上側の濾過室に充填されているものほど大きい。つまり、第１濾過室４ａの第１濾過粒子７ａの平均粒径よりもその直下の第２濾過室４ｂの第２濾過粒子７ｂの平均粒径が小さく、第２濾過室４ｂの第２濾過粒子７ｂの平均粒径よりもその直下の第３濾過室４ｃの第３濾過粒子７ｃの平均粒径が小さい。 The average particle diameter of the filtration particles 7a, 7b and 7c is larger as the upper filtration chamber is filled. That is, the average particle diameter of the second filtration particles 7b in the second filtration chamber 4b immediately below the average particle diameter of the first filtration particles 7a in the first filtration chamber 4a is smaller, and the second filtration particles in the second filtration chamber 4b. The average particle diameter of the third filtration particles 7c in the third filtration chamber 4c immediately below the average particle diameter of 7b is smaller.
　最も上側の第１濾過粒子７ａの平均粒径の下限としては、２００μｍが好ましく、２５０μｍがより好ましく、３００μｍがさらに好ましい。一方、第１濾過粒子７ａの平均粒径の上限としては、２０００μｍが好ましく、８００μｍがより好ましく、６００μｍがさらに好ましく、４００μｍが特に好ましい。第１濾過粒子７ａの平均粒径が上記下限に満たない場合、第１濾過室４ａに第１濾過粒子７ａによって形成される層の密度が大きく、隙間が小さくなるので、第１濾過室４ａの圧損が大きくなるおそれや、第１濾過室４ａの目詰まりの頻度が大きくなるおそれがある。逆に、第１濾過粒子７ａの平均粒径が上記上限を超える場合、第１濾過粒子７ａ間の隙間が大きくなり、十分に油分や濁質を除去できないおそれがある。 The lower limit of the average particle diameter of the uppermost first filtration particle 7a is preferably 200 μm, more preferably 250 μm, and even more preferably 300 μm. On the other hand, the upper limit of the average particle diameter of the first filter particles 7a is preferably 2000 μm, more preferably 800 μm, further preferably 600 μm, and particularly preferably 400 μm. When the average particle diameter of the first filtration particles 7a is less than the lower limit, the density of the layer formed by the first filtration particles 7a in the first filtration chamber 4a is large and the gap is small. There is a possibility that the pressure loss is increased and the frequency of clogging of the first filtration chamber 4a is increased. On the contrary, when the average particle diameter of the 1st filtration particle 7a exceeds the said upper limit, the clearance gap between the 1st filtration particles 7a becomes large, and there exists a possibility that an oil component and turbidity cannot fully be removed.
　第２濾過粒子７ｂの平均粒径の下限としては、８０μｍが好ましく、１００μｍがより好ましく、１２０μｍがさらに好ましい。一方、第２濾過粒子７ｂの平均粒径の上限としては、５００μｍが好ましく、３００μｍがより好ましく、２５０μｍがさらに好ましく２００μｍが特に好ましい。第２濾過粒子７ｂの平均粒径が上記下限に満たない場合、第２濾過室４ｂの圧損が大きくなるおそれや、第２濾過室４ｂの目詰まりの頻度が大きくなるおそれがある。逆に、第２濾過粒子７ｂの平均粒径が上記上限を超える場合、下側の第３濾過室４ｃの目詰まりの頻度が大きくなるおそれがある。 The lower limit of the average particle diameter of the second filtration particles 7b is preferably 80 μm, more preferably 100 μm, and even more preferably 120 μm. On the other hand, the upper limit of the average particle diameter of the second filtration particles 7b is preferably 500 μm, more preferably 300 μm, still more preferably 250 μm, and particularly preferably 200 μm. When the average particle diameter of the second filtration particle 7b is less than the lower limit, the pressure loss of the second filtration chamber 4b may be increased, or the frequency of clogging of the second filtration chamber 4b may be increased. Conversely, when the average particle diameter of the second filtration particles 7b exceeds the upper limit, the frequency of clogging of the lower third filtration chamber 4c may increase.
　最も下側の第３濾過粒子７ｃの平均粒径の下限としては、５μｍが好ましく、１０μｍがより好ましく、２０μｍがさらに好ましい。一方、第３濾過粒子７ｃの平均粒径の上限としては、２００μｍが好ましく、１２０μｍがより好ましく、１００μｍがさらに好ましく、８０μｍが特に好ましい。第３濾過粒子７ｃの平均粒径が上記下限に満たない場合、第３濾過室４ｃの圧損が大きくなるおそれや、コスト及び重量が増加するおそれがある。逆に、第３濾過粒子７ｃの平均粒径が上記上限を超える場合、当該下向流式濾過塔が微細な油滴や濁質を除去できないおそれがある。 The lower limit of the average particle diameter of the lowermost third filtration particle 7c is preferably 5 μm, more preferably 10 μm, and further preferably 20 μm. On the other hand, the upper limit of the average particle size of the third filtration particles 7c is preferably 200 μm, more preferably 120 μm, still more preferably 100 μm, and particularly preferably 80 μm. When the average particle size of the third filtration particles 7c is less than the lower limit, the pressure loss of the third filtration chamber 4c may increase, and the cost and weight may increase. On the contrary, when the average particle diameter of the 3rd filtration particle 7c exceeds the said upper limit, there exists a possibility that the said downward flow type filtration tower cannot remove a fine oil droplet and turbidity.
　また、濾過室４ａ，４ｂ，４ｃ毎の濾過粒子７ａ，７ｂ，７ｃの平均比重の下限としては、１．１が好ましく、１．４がより好ましい。一方、濾過粒子７ａ，７ｂ，７ｃの平均比重の上限としては、８が好ましく、５がより好ましい。濾過粒子７ａ，７ｂ，７ｃの平均比重が上記下限に満たない場合、濾過粒子７ａ，７ｂ，７ｃが沈降せず、濾過室４ａ，４ｂ，４ｃの中で被処理液を濾過する層を形成できないおそれがある。逆に、濾過粒子７ａ，７ｂ，７ｃの平均比重が上記上限を超える場合、逆洗時に濾過粒子７ａ，７ｂ，７ｃの層が流動化できず、洗浄効果を向上できないおそれがある。なお、濾過粒子７ａ，７ｂ，７ｃの平均比重は、濾過室毎に異なっていてもよい。 Also, the lower limit of the average specific gravity of the filtration particles 7a, 7b, 7c for each of the filtration chambers 4a, 4b, 4c is preferably 1.1, more preferably 1.4. On the other hand, the upper limit of the average specific gravity of the filtration particles 7a, 7b, 7c is preferably 8, and more preferably 5. When the average specific gravity of the filtration particles 7a, 7b, 7c is less than the lower limit, the filtration particles 7a, 7b, 7c do not settle, and a layer for filtering the liquid to be treated cannot be formed in the filtration chambers 4a, 4b, 4c. There is a fear. Conversely, when the average specific gravity of the filtration particles 7a, 7b, 7c exceeds the above upper limit, the layer of the filtration particles 7a, 7b, 7c cannot be fluidized during backwashing, and the cleaning effect may not be improved. In addition, the average specific gravity of the filtration particles 7a, 7b, and 7c may be different for each filtration chamber.
　濾過室４ａ，４ｂ，４ｃ毎の濾過粒子７ａ，７ｂ，７ｃの均等係数の下限としては、１．１が好ましく、１．３がより好ましい。一方、濾過粒子７ａ，７ｂ，７ｃの均等係数の上限としては、１．８が好ましく、１．６がより好ましい。濾過粒子７ａ，７ｂ，７ｃの均等係数が上記下限に満たない場合、各濾過粒子７ａ，７ｂ，７ｃの粒径のバラツキが小さ過ぎて緻密に堆積させることができないおそれがある。逆に、濾過粒子７ａ，７ｂ，７ｃの均等係数が上記上限を超える場合、濾過室４ａ，４ｂ，４ｃの内部で油滴や濁質の分離能力が不均一となるおそれがある。ここで、「均等係数」とは、ＪＩＳ－Ｚ８８０１－１（２００６）に規定される篩を用い、目開きの大きい篩から順に篩分けて目開きを通過する粒子の質量割合を測定し、公称目開きを粒径として作成される粒径分布において積算質量が６０％となる値（ｄ６０）を積算質量が１０％となる値（ｄ１０）で除した値である。 The lower limit of the uniformity coefficient of the filtration particles 7a, 7b, 7c for the filtration chambers 4a, 4b, 4c is preferably 1.1, and more preferably 1.3. On the other hand, the upper limit of the uniformity coefficient of the filtration particles 7a, 7b, and 7c is preferably 1.8, and more preferably 1.6. When the uniformity coefficient of the filtration particles 7a, 7b, and 7c is less than the lower limit, the variation in the particle diameter of the filtration particles 7a, 7b, and 7c may be too small to be densely deposited. On the contrary, when the uniformity coefficient of the filtration particles 7a, 7b, and 7c exceeds the upper limit, there is a possibility that the separation ability of oil droplets and turbidity may not be uniform inside the filtration chambers 4a, 4b, and 4c. Here, the “uniformity coefficient” is a sieve defined in JIS-Z8801-1 (2006), and the mass ratio of particles passing through the openings is measured by sieving in order from the sieve with the larger openings. This is a value obtained by dividing the value (d60) at which the integrated mass is 60% in the particle size distribution created by using the aperture as the particle size by the value (d10) at which the integrated mass is 10%.
　定常状態において最も上側の第１濾過粒子７ａが形成する層の平均厚さとしては、特に限定されないが、例えば１０ｃｍ以上１ｍ以下とすることができる。定常状態において第２濾過粒子７ｂが形成する層の平均厚さとしては、特に限定されないが、例えば５ｃｍ以上８０ｃｍ以下とすることができる。また、定常状態において最も下側の第３濾過粒子７ｃが形成する層の平均厚さとしては、特に限定されないが、例えば１ｃｍ以上５０ｃｍ以下とすることができる。 The average thickness of the layer formed by the uppermost first filtration particle 7a in the steady state is not particularly limited, but may be, for example, 10 cm or more and 1 m or less. Although it does not specifically limit as average thickness of the layer which the 2nd filtration particle 7b forms in a steady state, For example, it can be 5 cm or more and 80 cm or less. In addition, the average thickness of the layer formed by the lowermost third filtration particle 7c in the steady state is not particularly limited, but may be, for example, 1 cm or more and 50 cm or less.
（洗浄粒子）
　洗浄粒子８ａ，８ｂ，８ｃは、逆洗時に舞い上がり、油分や濁質で固まった濾過粒子７ａ，７ｂ，７ｃの層をほぐして隙間を形成することにより、濾過粒子７ａ，７ｂ，７ｃの洗浄効果を促進する。 (Washing particles)
The cleaning particles 8a, 8b, and 8c rise at the time of backwashing and loosen the layer of the filtration particles 7a, 7b, and 7c solidified by oil and turbidity to form a gap, thereby cleaning the filtering particles 7a, 7b, and 7c. Promote.
　この洗浄粒子８ａ，８ｂ，８ｃとしては、天然砂、無機物、セラミックス、金属（金属化合物を含む）、ポリマー、天然有機素材等を主成分とする粒子を用いることができ、中でも、セラミックス、金属又はポリマーを主成分とする粒子が好ましい。洗浄粒子８ａ，８ｂ，８ｃの主成分がセラミックス、金属又はポリマーであることによって、濾過粒子７ａ，７ｂ，７ｃに対する比重の比率を容易に適正化でき、濾過粒子７ａ，７ｂ，７ｃの洗浄効果を得易い。なお、洗浄粒子８ａ，８ｂ，８ｃの材質は、濾過室毎に異なっていてもよく、それぞれ複数種類の粒子を含んでもよい。 As the cleaning particles 8a, 8b, 8c, particles mainly composed of natural sand, inorganic substances, ceramics, metals (including metal compounds), polymers, natural organic materials, etc. can be used. Particles based on polymers are preferred. Since the main component of the cleaning particles 8a, 8b, and 8c is ceramic, metal, or polymer, the ratio of specific gravity with respect to the filtering particles 7a, 7b, and 7c can be easily optimized, and the cleaning effect of the filtering particles 7a, 7b, and 7c can be improved. Easy to get. The material of the cleaning particles 8a, 8b, and 8c may be different for each filtration chamber, and may include a plurality of types of particles.
　洗浄粒子８ａ，８ｂ，８ｃの主成分とされるセラミックスとしては、例えばガラス、シリカ、アルミナ等を主成分とするものが挙げられる。 Examples of ceramics that are the main components of the cleaning particles 8a, 8b, and 8c include those containing glass, silica, alumina, and the like as main components.
　洗浄粒子８ａ，８ｂ，８ｃの主成分とされる金属としては、例えば耐錆性に優れる酸化鉄等が挙げられる。 Examples of the metal that is the main component of the cleaning particles 8a, 8b, and 8c include iron oxide having excellent rust resistance.
　洗浄粒子８ａ，８ｂ，８ｃの主成分とされるポリマーとしては、例えばフッ素樹脂、ビニル樹脂、ポリオレフィン、ポリウレタン、エポキシ樹脂、アクリル樹脂、ポリエステル、ポリアミド、ポリイミド、メラミン樹脂、ポリカーボネート等を挙げることができる。
これらの中でも耐水性、耐油性等に優れるフッ素樹脂、ビニル樹脂、ポリウレタン、エポキシ樹脂及びアクリル樹脂が好ましく、耐食性に優れるフッ素樹脂がより好ましい。 Examples of the polymer that is the main component of the cleaning particles 8a, 8b, and 8c include a fluororesin, vinyl resin, polyolefin, polyurethane, epoxy resin, acrylic resin, polyester, polyamide, polyimide, melamine resin, and polycarbonate. .
Among these, a fluororesin, a vinyl resin, a polyurethane, an epoxy resin, and an acrylic resin excellent in water resistance and oil resistance are preferable, and a fluororesin excellent in corrosion resistance is more preferable.
　また、洗浄粒子８ａ，８ｂ，８ｃの主成分とされる天然砂としては、例えばアンスラサイト、ガーネット、マンガン砂等を挙げることができる。洗浄粒子８ａ，８ｂ，８ｃの主成分とされる天然有機素材としては、天然の有機物を篩い分けして粒子サイズを整えたものを使用することができる。 Further, examples of natural sand that is the main component of the cleaning particles 8a, 8b, and 8c include anthracite, garnet, and manganese sand. As the natural organic material which is the main component of the cleaning particles 8a, 8b and 8c, a natural organic material having a particle size adjusted by sieving can be used.
　また、洗浄粒子８ａ，８ｂ，８ｃとして使用される無機物を主成分とする好ましい粒子としては、例えばガラスビーズを挙げることができる。ガラスビーズは、粒径及び比重が揃ったものを比較的容易に入手できるため、安定した洗浄効果を与えることができる。特に好ましいガラスビーズとしては、例えばアルミナを含有する球状ガラスビーズを用いることができる。このようなガラスビーズは、油の付着によっても塊に成長し難く、洗浄時に分散して流動し易いという長所を有する。 Further, as preferred particles mainly composed of an inorganic substance used as the cleaning particles 8a, 8b, 8c, for example, glass beads can be mentioned. Since glass beads having a uniform particle size and specific gravity can be obtained relatively easily, a stable cleaning effect can be provided. As particularly preferred glass beads, for example, spherical glass beads containing alumina can be used. Such glass beads have an advantage that they are difficult to grow into a lump even when oil adheres, and are easy to disperse and flow during washing.
　洗浄粒子８ａ，８ｂ，８ｃの形状としては、特に限定されず、例えば球形、柱形等任意の形状とすることができる。特に、洗浄粒子８ａ，８ｂ，８ｃとして、不定形の粉砕粒子を用いることで、逆洗時の濾過粒子の洗浄効果をより促進することができる。 The shape of the cleaning particles 8a, 8b, and 8c is not particularly limited, and may be any shape such as a spherical shape or a column shape. In particular, by using irregularly pulverized particles as the cleaning particles 8a, 8b, and 8c, it is possible to further promote the cleaning effect of the filtered particles during backwashing.
　第１洗浄粒子８ａは第１濾過粒子７ａよりも平均粒径及び平均比重が大きく、第２洗浄粒子８ｂは第２濾過粒子７ｂよりも平均粒径及び平均比重が大きく、第３洗浄粒子８ｃは第３濾過粒子７ｃよりも平均粒径及び平均比重が大きいことが好ましい。このように、洗浄粒子８ａ，８ｂ，８ｃの平均粒径及び平均比重が同じ濾過室４ａ，４ｂ，４ｃの濾過粒子７ａ，７ｂ，７ｃよりも大きいことにより、沈降速度の差により下側の洗浄粒子８ａ，８ｂ，８ｃの層と上側の濾過粒子７ａ，７ｂ，７ｃの層とを効率よく層分けできる。 The first cleaning particles 8a have a larger average particle size and average specific gravity than the first filtration particles 7a, the second cleaning particles 8b have a larger average particle size and average specific gravity than the second filtration particles 7b, and the third cleaning particles 8c It is preferable that an average particle diameter and an average specific gravity are larger than the 3rd filtration particle 7c. Thus, since the average particle diameter and average specific gravity of the cleaning particles 8a, 8b, and 8c are larger than those of the filtration particles 7a, 7b, and 7c in the same filtration chamber 4a, 4b, and 4c, the lower cleaning is performed due to the difference in sedimentation speed. The layer of the particles 8a, 8b, and 8c and the layer of the upper filtration particles 7a, 7b, and 7c can be efficiently divided into layers.
　第１洗浄粒子８ａの平均粒径の第１濾過粒子７ａの平均粒径に対する比、第２洗浄粒子８ｂの平均粒径の第２濾過粒子７ｂの平均粒径に対する比、及び第３洗浄粒子８ｃの平均粒径の第３濾過粒子７ｃの平均粒径に対する比の下限としては、１．２が好ましく、１．５がより好ましい。一方、上記平均粒径の比の上限としては、１０が好ましく、８がより好ましい。上記平均粒径の比が上記下限に満たない場合、逆洗時の洗浄粒子８ａ，８ｂ，８ｃの濾過粒子７ａ，７ｂ，７ｃに対する衝突エネルギーが小さく、濾過粒子７ａ，７ｂ，７ｃの層を割りほぐすことができないおそれや、逆洗後に洗浄粒子８ａ，８ｂ，８ｃが濾過粒子７ａ，７ｂ，７ｃより先に沈降せず、濾過粒子７ａ，７ｂ，７ｃの層を形成できないおそれがある。逆に、上記平均粒径の比が上記上限を超える場合、濾過粒子７ａ，７ｂ，７ｃが洗浄粒子８ａ，８ｂ，８ｃ間の隙間に入り込んで十分な厚さの濾過層を形成できないおそれがある。 The ratio of the average particle size of the first cleaning particles 8a to the average particle size of the first filtered particles 7a, the ratio of the average particle size of the second cleaning particles 8b to the average particle size of the second filtered particles 7b, and the third cleaning particles 8c As a lower limit of the ratio of the average particle diameter to the average particle diameter of the third filtered particles 7c, 1.2 is preferable, and 1.5 is more preferable. On the other hand, the upper limit of the ratio of the average particle diameter is preferably 10, and more preferably 8. When the ratio of the average particle diameter is less than the lower limit, the collision energy of the cleaning particles 8a, 8b, and 8c with respect to the filtration particles 7a, 7b, and 7c during backwashing is small, and the layers of the filtration particles 7a, 7b, and 7c are broken up. There is a possibility that the cleaning particles 8a, 8b, and 8c do not settle before the filtering particles 7a, 7b, and 7c after backwashing, and a layer of the filtering particles 7a, 7b, and 7c cannot be formed. On the other hand, when the ratio of the average particle diameters exceeds the upper limit, the filtration particles 7a, 7b, 7c may enter the gaps between the cleaning particles 8a, 8b, 8c and may not form a sufficiently thick filtration layer. .
　第１洗浄粒子８ａの平均比重の第１濾過粒子７ａの平均比重に対する比、第２洗浄粒子８ｂの平均比重の第２濾過粒子７ｂの平均比重に対する比、及び第３洗浄粒子８ｃの平均比重の第３濾過粒子７ｃの平均比重に対する比の下限としては、１．５が好ましく、２がより好ましい。一方、上記平均比重の比の上限としては、１０が好ましく、８がより好ましい。上記平均比重の比が上記下限に満たない場合、逆洗時の洗浄粒子８ａ，８ｂ，８ｃの濾過粒子７ａ，７ｂ，７ｃに対する衝突エネルギーが小さく、濾過粒子７ａ，７ｂ，７ｃの層を割りほぐすことができないおそれや、逆洗後に洗浄粒子８ａ，８ｂ，８ｃが濾過粒子７ａ，７ｂ，７ｃより先に沈降せず、濾過粒子７ａ，７ｂ，７ｃの層を形成できないおそれがある。逆に、上記平均比重の比が上記上限を超える場合、濾過粒子７ａ，７ｂ，７ｃが洗浄粒子８ａ，８ｂ，８ｃ間の隙間に入り込んで十分な厚さの濾過層を形成できないおそれがある。 The ratio of the average specific gravity of the first cleaning particles 8a to the average specific gravity of the first filtered particles 7a, the ratio of the average specific gravity of the second cleaning particles 8b to the average specific gravity of the second filtered particles 7b, and the average specific gravity of the third cleaning particles 8c. The lower limit of the ratio of the third filtered particles 7c to the average specific gravity is preferably 1.5 and more preferably 2. On the other hand, the upper limit of the ratio of the average specific gravity is preferably 10, and more preferably 8. When the ratio of the average specific gravity is less than the lower limit, the collision energy of the cleaning particles 8a, 8b, and 8c with the filtering particles 7a, 7b, and 7c during backwashing is small, and the layers of the filtering particles 7a, 7b, and 7c are broken up. The cleaning particles 8a, 8b, 8c may not settle before the filtered particles 7a, 7b, 7c after backwashing, and the layers of the filtered particles 7a, 7b, 7c may not be formed. On the other hand, when the ratio of the average specific gravity exceeds the upper limit, the filtration particles 7a, 7b, 7c may enter the gaps between the cleaning particles 8a, 8b, 8c, and a filtration layer having a sufficient thickness may not be formed.
　第１洗浄粒子８ａは、直下の第２濾過室４ｂの第２洗浄粒子８ｂよりも平均粒径及び平均比重が大きく、第２洗浄粒子８ｂは、直下の第３濾過室４ｃの第３洗浄粒子８ｃよりも平均粒径及び平均比重が大きい。 The first cleaning particles 8a have a larger average particle size and average specific gravity than the second cleaning particles 8b in the second filtration chamber 4b directly below, and the second cleaning particles 8b are the third cleaning particles in the third filtration chamber 4c directly below. Average particle diameter and average specific gravity are larger than 8c.
　第１洗浄粒子８ａの平均粒径の第２洗浄粒子８ｂの平均粒径に対する比、及び第２洗浄粒子８ｂの平均粒径の第３洗浄粒子８ｃの平均粒径に対する比、つまり各濾過室の洗浄粒子の平均粒径の、その濾過室直下の濾過室の洗浄粒子の平均粒径に対する比の下限としては、１．５が好ましく、２がより好ましい。上記平均粒径の比の上限としては、１０が好ましく、８がより好ましい。上記平均粒径の比が上記下限に満たない場合、隣接する濾過室の間で濾過粒子の平均粒径に十分な差をつけることができず、下側の濾過室に形成される濾過粒子の層の濾過能力が不十分となるおそれがある。逆に、上記平均粒径の比が上記上限を超える場合、隣接する濾過室の間で濾過粒子の平均粒径の差が過大となり、下側の濾過室に形成される濾過粒子の層が油分や濁質で目詰まりし易くなるおそれがある。 The ratio of the average particle size of the first cleaning particles 8a to the average particle size of the second cleaning particles 8b, and the ratio of the average particle size of the second cleaning particles 8b to the average particle size of the third cleaning particles 8c, that is, each filtration chamber The lower limit of the ratio of the average particle diameter of the cleaning particles to the average particle diameter of the cleaning particles in the filtration chamber immediately below the filtration chamber is preferably 1.5 and more preferably 2. The upper limit of the average particle size ratio is preferably 10, and more preferably 8. When the ratio of the average particle diameter is less than the lower limit, a sufficient difference in the average particle diameter of the filtration particles cannot be made between adjacent filtration chambers, and the filtration particles formed in the lower filtration chamber There is a risk that the filtration capacity of the layer will be insufficient. Conversely, if the ratio of the average particle diameter exceeds the upper limit, the difference in the average particle diameter of the filtration particles between adjacent filtration chambers is excessive, and the layer of filtration particles formed in the lower filtration chamber is oily. There is a risk of clogging due to turbidity.
　最も上側の第１洗浄粒子８ａの平均粒径の下限としては、２５０μｍが好ましく、３００μｍがより好ましく、３５０μｍがさらに好ましい。一方、第１洗浄粒子８ａの平均粒径の上限としては、３０００μｍが好ましく、２４００μｍがより好ましく、１８００μｍがさらに好ましく、１２００μｍが特に好ましい。第１洗浄粒子８ａの平均粒径が上記下限に満たない場合、第１洗浄粒子８ａによって形成される層の密度が大きく、圧損が大きくなるおそれがある。逆に、第１洗浄粒子８ａの平均粒径が上記上限を超える場合、第１洗浄粒子８ａ間の隙間に第１濾過粒子７ａが入り込み、第１濾過粒子７ａの層を効率よく形成できないおそれがある。 The lower limit of the average particle diameter of the uppermost first cleaning particle 8a is preferably 250 μm, more preferably 300 μm, and further preferably 350 μm. On the other hand, the upper limit of the average particle size of the first cleaning particles 8a is preferably 3000 μm, more preferably 2400 μm, further preferably 1800 μm, and particularly preferably 1200 μm. When the average particle diameter of the first cleaning particles 8a is less than the lower limit, the density of the layer formed by the first cleaning particles 8a is large, and the pressure loss may increase. Conversely, if the average particle size of the first cleaning particles 8a exceeds the above upper limit, the first filtration particles 7a may enter the gaps between the first cleaning particles 8a, and the layer of the first filtration particles 7a may not be efficiently formed. is there.
　第２洗浄粒子８ｂの平均粒径の下限としては、１００μｍが好ましく、１２０μｍがより好ましく、１５０μｍがさらに好ましい。一方、第２洗浄粒子８ｂの平均粒径の上限としては、１５００μｍが好ましく、９００μｍがより好ましく、７５０μｍがさらに好ましく、６００μｍが特に好ましい。第２洗浄粒子８ｂの平均粒径が上記下限に満たない場合、第２洗浄粒子８ｂによって形成される層の密度が大きく、圧損が大きくなるおそれがある。逆に、第２洗浄粒子８ｂの平均粒径が上記上限を超える場合、第２洗浄粒子８ｂ間の隙間に第２濾過粒子７ｂが入り込み、第２濾過粒子７ｂの層を効率よく形成できないおそれがある。 The lower limit of the average particle size of the second cleaning particles 8b is preferably 100 μm, more preferably 120 μm, and even more preferably 150 μm. On the other hand, the upper limit of the average particle size of the second cleaning particles 8b is preferably 1500 μm, more preferably 900 μm, further preferably 750 μm, and particularly preferably 600 μm. If the average particle size of the second cleaning particles 8b is less than the lower limit, the density of the layer formed by the second cleaning particles 8b may be large and the pressure loss may increase. Conversely, when the average particle size of the second cleaning particles 8b exceeds the above upper limit, the second filtration particles 7b may enter the gaps between the second cleaning particles 8b, and the layer of the second filtration particles 7b may not be formed efficiently. is there.
　最も下側の第３洗浄粒子８ｃの平均粒径の下限としては、６μｍが好ましく、１２μｍがより好ましく、２５μｍがさらに好ましい。一方、第３洗浄粒子８ｃの平均粒径の上限としては、５００μｍが好ましく、３５０μｍがより好ましく、３００μｍがさらに好ましく、２５０μｍが特に好ましい。第３洗浄粒子８ｃの平均粒径が上記下限に満たない場合、第３洗浄粒子８ｃによって形成される層の密度が大きく、圧損が大きくなるおそれがある。逆に、第３洗浄粒子８ｃの平均粒径が上記上限を超える場合、第３洗浄粒子８ｃ間の隙間に第３濾過粒子７ｃが入り込み、第３濾過粒子７ｃの層を効率よく形成できないおそれがある。 The lower limit of the average particle diameter of the lowermost third cleaning particle 8c is preferably 6 μm, more preferably 12 μm, and even more preferably 25 μm. On the other hand, the upper limit of the average particle size of the third cleaning particles 8c is preferably 500 μm, more preferably 350 μm, further preferably 300 μm, and particularly preferably 250 μm. When the average particle size of the third cleaning particles 8c is less than the lower limit, the density of the layer formed by the third cleaning particles 8c is large, and the pressure loss may be increased. Conversely, if the average particle size of the third cleaning particles 8c exceeds the upper limit, the third filtration particles 7c may enter the gaps between the third cleaning particles 8c, and the third filtration particle 7c layer may not be formed efficiently. is there.
　濾過室４ａ，４ｂ，４ｃ毎の洗浄粒子８ａ，８ｂ，８ｃの均等係数の下限としては、１．１が好ましく、１．３がより好ましい。一方、洗浄粒子８ａ，８ｂ，８ｃの均等係数の上限としては、１．８が好ましく、１．６がより好ましい。洗浄粒子８ａ，８ｂ，８ｃの均等係数が上記下限に満たない場合、各洗浄粒子８ａ，８ｂ，８ｃの粒径のバラツキが小さ過ぎて濾過粒子７ａ，７ｂ，７ｃの洗浄効率が不十分となるおそれがある。逆に、洗浄粒子８ａ，８ｂ，８ｃの均等係数が上記上限を超える場合、洗浄粒子８ａ，８ｂ，８ｃの隙間が小さくなり油滴や濁質で目詰まりするおそれがある。 The lower limit of the uniformity coefficient of the cleaning particles 8a, 8b, 8c for each of the filtration chambers 4a, 4b, 4c is preferably 1.1 and more preferably 1.3. On the other hand, the upper limit of the uniformity coefficient of the cleaning particles 8a, 8b, and 8c is preferably 1.8 and more preferably 1.6. When the uniformity coefficient of the cleaning particles 8a, 8b, and 8c is less than the above lower limit, the variation in the particle size of the cleaning particles 8a, 8b, and 8c is too small and the cleaning efficiency of the filtration particles 7a, 7b, and 7c becomes insufficient. There is a fear. On the other hand, when the uniformity coefficient of the cleaning particles 8a, 8b, and 8c exceeds the upper limit, the gap between the cleaning particles 8a, 8b, and 8c may become small and clogged with oil droplets or turbidity.
　第１洗浄粒子８ａの平均比重の第２洗浄粒子８ｂの平均比重に対する比、及び第２洗浄粒子８ｂの平均比重の第３洗浄粒子８ｃの平均比重に対する比、つまり各濾過室の洗浄粒子の平均比重の、その直下の濾過室の洗浄粒子の平均比重に対する比の下限としては、１．１が好ましく、１．２がより好ましい。上記平均比重の比の上限としては、２が好ましく、１．８がより好ましい。上記平均比重の比が上記下限に満たない場合、隣接する濾過室の間で濾過粒子の平均比重に十分な差をつけることができず、下側の濾過室に形成される濾過粒子の層の濾過能力が不十分となるおそれがある。逆に、上記平均比重の比が上記上限を超える場合、隣接する濾過室の間で濾過粒子の平均比重の差が過大となり、下側の濾過室に形成される濾過粒子の層が油分や濁質で目詰まりし易くなるおそれがある。 The ratio of the average specific gravity of the first cleaning particles 8a to the average specific gravity of the second cleaning particles 8b and the ratio of the average specific gravity of the second cleaning particles 8b to the average specific gravity of the third cleaning particles 8c, that is, the average of the cleaning particles in each filtration chamber The lower limit of the ratio of the specific gravity to the average specific gravity of the cleaning particles in the filtration chamber immediately below is preferably 1.1, and more preferably 1.2. The upper limit of the average specific gravity ratio is preferably 2, and more preferably 1.8. When the ratio of the average specific gravity is less than the lower limit, it is not possible to make a sufficient difference in the average specific gravity of the filtration particles between the adjacent filtration chambers, and the filtration particle layer formed in the lower filtration chamber There is a risk of insufficient filtration capacity. Conversely, when the ratio of the average specific gravity exceeds the upper limit, the difference in the average specific gravity of the filtration particles between adjacent filtration chambers becomes excessive, and the layer of filtration particles formed in the lower filtration chamber becomes oily or turbid. There is a risk of clogging with quality.
　最も上側の第１洗浄粒子８ａの平均比重の下限としては、１．５が好ましく、２がより好ましい。一方、第１洗浄粒子８ａの平均比重の上限としては、１５が好ましく、１０がより好ましい。第１洗浄粒子８ａの平均比重が上記下限に満たない場合、沈降速度が小さくなり第１濾過粒子７ａとの層分けが不十分となるおそれがある。逆に、第１洗浄粒子８ａの平均比重が上記上限を超える場合、逆洗時に第１洗浄粒子８ａが浮き上がらず、第１濾過粒子７ａの洗浄を促進できないおそれがある。 The lower limit of the average specific gravity of the uppermost first cleaning particle 8a is preferably 1.5 and more preferably 2. On the other hand, the upper limit of the average specific gravity of the first cleaning particles 8a is preferably 15, and more preferably 10. When the average specific gravity of the 1st washing | cleaning particle | grains 8a is less than the said minimum, there exists a possibility that sedimentation rate may become small and layering with the 1st filtration particle 7a may become inadequate. Conversely, when the average specific gravity of the first cleaning particles 8a exceeds the above upper limit, the first cleaning particles 8a do not float during backwashing, and the cleaning of the first filtration particles 7a may not be promoted.
　第２洗浄粒子８ｂの平均比重の下限としては、１．３が好ましく、１．７がより好ましい。一方、第２洗浄粒子８ｂの平均比重の上限としては、１０が好ましく、７がより好ましい。第２洗浄粒子８ｂの平均比重が上記下限に満たない場合、沈降速度が小さくなり第２濾過粒子７ｂとの層分けが不十分となるおそれがある。逆に、第２洗浄粒子８ｂの平均比重が上記上限を超える場合、逆洗時に第２洗浄粒子８ｂが浮き上がらず、第２濾過粒子７ｂの洗浄を促進できないおそれがある。 The lower limit of the average specific gravity of the second cleaning particles 8b is preferably 1.3 and more preferably 1.7. On the other hand, the upper limit of the average specific gravity of the second cleaning particles 8b is preferably 10, and more preferably 7. When the average specific gravity of the second cleaning particles 8b is less than the above lower limit, the sedimentation speed is decreased, and there is a possibility that the layering with the second filtration particles 7b is insufficient. On the other hand, when the average specific gravity of the second cleaning particles 8b exceeds the above upper limit, the second cleaning particles 8b do not float during backwashing, and the cleaning of the second filtration particles 7b may not be promoted.
　最も下側の第３洗浄粒子８ｃの平均比重の下限としては、１．１が好ましく、１．５がより好ましい。一方、第３洗浄粒子８ｃの平均比重の上限としては、７が好ましく、５がより好ましい。第３洗浄粒子８ｃの平均比重が上記下限に満たない場合、沈降速度が小さくなり第３濾過粒子７ｃとの層分けが不十分となるおそれがある。逆に、第３洗浄粒子８ｃの平均比重が上記上限を超える場合、逆洗時に第３洗浄粒子８ｃが浮き上がらず、第３濾過粒子７ｃの洗浄を促進できないおそれがある。 The lower limit of the average specific gravity of the lowermost third cleaning particle 8c is preferably 1.1, and more preferably 1.5. On the other hand, the upper limit of the average specific gravity of the third cleaning particles 8c is preferably 7, and more preferably 5. When the average specific gravity of the 3rd washing | cleaning particle | grains 8c is less than the said minimum, there exists a possibility that sedimentation rate may become small and layering with the 3rd filtration particle | grains 7c may become inadequate. On the other hand, when the average specific gravity of the third cleaning particles 8c exceeds the above upper limit, the third cleaning particles 8c do not float during backwashing, and there is a possibility that the cleaning of the third filtration particles 7c cannot be promoted.
　濾過室の洗浄粒子の充填質量割合は、その濾過室直下の濾過室の洗浄粒子の充填質量割合よりも大きいことが好ましい。つまり、濾過室４ａ，４ｂ，４ｃ中の洗浄粒子８ａ，８ｂ，８ｃの充填質量割合は、上側の濾過室ほど大きいことが好ましい。濾過粒子７ａ，７ｂ，７ｃの汚れが上側の濾過室ほど大きくなるので、上側の濾過室ほど洗浄粒子の充填質量割合を大きくすることにより、濾過粒子７ａ，７ｂ，７ｃを効率よく洗浄できると共に、下側の濾過室の高さを小さくして当該下向流式濾過塔を小型化できる。 The filling mass ratio of the cleaning particles in the filtration chamber is preferably larger than the filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber. That is, it is preferable that the filling mass ratio of the cleaning particles 8a, 8b, and 8c in the filtration chambers 4a, 4b, and 4c is larger in the upper filtration chamber. Since the dirt of the filtration particles 7a, 7b, and 7c becomes larger in the upper filtration chamber, the filtration particles 7a, 7b, and 7c can be efficiently washed by increasing the filling mass ratio of the washing particles in the upper filtration chamber. By reducing the height of the lower filtration chamber, the downflow filtration tower can be miniaturized.
　第１濾過室４ａでの第１洗浄粒子８ａの充填質量割合と第２濾過室４ｂでの第２洗浄粒子８ｂの充填質量割合との差、及び第２濾過室４ｂでの第２洗浄粒子８ｂの充填質量割合と第３濾過室４ｃでの第３洗浄粒子８ｃの充填質量割合との差、つまり各濾過室の洗浄粒子の充填質量割合とその濾過室直下の濾過室の洗浄粒子の充填質量割合との差の下限としては、５％が好ましく、７％がより好ましい。一方、上記充填質量割合の差の上限としては、２０％が好ましく、１５％がより好ましい。上記充填質量割合の差が上記下限に満たない場合、上側の濾過室の洗浄粒子が少なくなり濾過粒子の洗浄効率が不十分となるおそれや、下側の濾過室の洗浄粒子が多くなり当該下向流式濾過塔が不必要に大きくなるおそれがある。逆に、上記充填質量割合の差が上記上限を超える場合、上側の洗浄粒子が多くなり当該下向流式濾過塔が不必要に大きくなるおそれや、下側の濾過室の洗浄粒子が少なくなり濾過粒子の洗浄効率が不十分となるおそれがある。 The difference between the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a and the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b, and the second cleaning particles 8b in the second filtration chamber 4b. Difference between the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c, that is, the filling mass ratio of the cleaning particles in each filtration chamber and the filling mass of the cleaning particles in the filtration chamber immediately below the filtration chamber As a minimum of a difference with a rate, 5% is preferred and 7% is more preferred. On the other hand, the upper limit of the difference in the filling mass ratio is preferably 20%, more preferably 15%. If the difference in the filling mass ratio is less than the above lower limit, the cleaning particles in the upper filtration chamber may be reduced and the cleaning efficiency of the filtration particles may be insufficient, or the cleaning particles in the lower filtration chamber may be increased. There is a possibility that the counter-flow filter tower becomes unnecessarily large. On the contrary, when the difference in the filling mass ratio exceeds the upper limit, the upper cleaning particles increase, the downflow filtration tower may become unnecessarily large, and the cleaning particles in the lower filtration chamber decrease. There is a possibility that the cleaning efficiency of the filtered particles may be insufficient.
　第１濾過室４ａにおける第１洗浄粒子８ａの充填質量割合の下限としては、１５質量％が好ましく、２０質量％がより好ましい。一方、第１濾過室４ａにおける第１洗浄粒子８ａの充填質量割合の上限としては、５０質量％が好ましく、４５質量％がより好ましい。
第１濾過室４ａにおける第１洗浄粒子８ａの充填質量割合が上記下限に満たない場合、逆洗時に第１濾過粒子７ａの洗浄を十分促進できないおそれがある。逆に、第１濾過室４ａにおける第１洗浄粒子８ａの充填質量割合が上記上限を超える場合、第１濾過室４ａを大きくする必要があるため、当該下向流式濾過塔が不必要に大きくなるおそれがある。 As a minimum of the filling mass ratio of the 1st washing particle 8a in the 1st filtration room 4a, 15 mass% is preferred and 20 mass% is more preferred. On the other hand, the upper limit of the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a is preferably 50% by mass, and more preferably 45% by mass.
When the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a is less than the lower limit, there is a possibility that the cleaning of the first filtration particles 7a cannot be sufficiently promoted during backwashing. On the contrary, when the filling mass ratio of the first cleaning particles 8a in the first filtration chamber 4a exceeds the above upper limit, the first filtration chamber 4a needs to be enlarged, so that the downflow type filtration tower is unnecessarily large. There is a risk.
　第２濾過室４ｂにおける第２洗浄粒子８ｂの充填質量割合の下限としては、１０質量％が好ましく、１５質量％がより好ましい。一方、第２濾過室４ｂにおける第２洗浄粒子８ｂの充填質量割合の上限としては、４５質量％が好ましく、４０質量％がより好ましい。
第２濾過室４ｂにおける第２洗浄粒子８ｂの充填質量割合が上記下限に満たない場合、逆洗時に第２濾過粒子７ｂの洗浄を十分促進できないおそれがある。逆に、第２濾過室４ｂにおける第２洗浄粒子８ｂの充填質量割合が上記上限を超える場合、第２濾過室４ｂを大きくする必要があるため、当該下向流式濾過塔が不必要に大きくなるおそれがある。 The lower limit of the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b is preferably 10% by mass, and more preferably 15% by mass. On the other hand, the upper limit of the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b is preferably 45 mass%, more preferably 40 mass%.
When the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b is less than the lower limit, there is a possibility that the cleaning of the second filtration particles 7b cannot be sufficiently promoted during backwashing. On the contrary, when the filling mass ratio of the second cleaning particles 8b in the second filtration chamber 4b exceeds the above upper limit, the second filtration chamber 4b needs to be enlarged, so that the downflow type filtration tower is unnecessarily large. There is a risk.
　第３濾過室４ｃにおける第３洗浄粒子８ｃの充填質量割合の下限としては、５質量％が好ましく、１０質量％がより好ましい。一方、第３濾過室４ｃにおける第３洗浄粒子８ｃの充填質量割合の上限としては、４０質量％が好ましく、３５質量％がより好ましい。第３濾過室４ｃにおける第３洗浄粒子８ｃの充填質量割合が上記下限に満たない場合、逆洗時に第３濾過粒子７ｃの洗浄を十分促進できないおそれがある。逆に、第３濾過室４ｃにおける第３洗浄粒子８ｃの充填質量割合が上記上限を超える場合、第３濾過室４ｃを大きくする必要があるため、当該下向流式濾過塔が不必要に大きくなるおそれがある。 The lower limit of the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c is preferably 5% by mass, and more preferably 10% by mass. On the other hand, the upper limit of the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c is preferably 40% by mass, and more preferably 35% by mass. When the filling mass ratio of the 3rd washing | cleaning particle 8c in the 3rd filtration chamber 4c is less than the said minimum, there exists a possibility that washing | cleaning of the 3rd filtration particle 7c cannot fully be accelerated | stimulated at the time of backwashing. On the contrary, when the filling mass ratio of the third cleaning particles 8c in the third filtration chamber 4c exceeds the upper limit, the third filtration chamber 4c needs to be enlarged, so that the downflow type filtration tower is unnecessarily large. There is a risk.
（ヘッドスペース）
　定常状態の濾過室４ａ，４ｂ，４ｃにおいて、濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃの上方にそれぞれ形成されるヘッドスペース９ａ，９ｂ，９ｃは、逆洗時において濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃが洗浄水の流れにより舞い上がって互いにぶつかり合うよう運動するためのスペースを提供する。 (Headspace)
In the filtration chambers 4a, 4b, and 4c in the steady state, the head spaces 9a, 9b, and 9c formed above the filtration particles 7a, 7b, and 7c and the washing particles 8a, 8b, and 8c, respectively, , 7b, 7c and the cleaning particles 8a, 8b, 8c move up by the flow of the cleaning water and move to collide with each other.
　このヘッドスペース９ａ，９ｂ，９ｃの平均高さの下限としては、濾過室４ａ，４ｂ，４ｃの平均高さ（下側仕切板３ａ，３ｂ，３ｃと上側仕切板２ａ，２ｂ，２ｃとの平均間隔）の３０％が好ましく、５０％がより好ましい。一方、ヘッドスペース９ａ，９ｂ，９ｃの平均高さの上限としては、濾過室４ａ，４ｂ，４ｃの平均高さの８０％が好ましく、７０％がより好ましい。ヘッドスペース９ａ，９ｂ，９ｃの平均高さが上記下限に満たない場合、逆洗時に濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃが十分に運動できず、濾過粒子７ａ，７ｂ，７ｃの洗浄効果を十分に促進できないおそれがある。逆に、ヘッドスペース９ａ，９ｂ，９ｃの平均高さが上記上限を超える場合、スペースが大きくなり過ぎて逆洗時に濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃが当接する頻度が小さくなることにより濾過粒子７ａ，７ｂ，７ｃの洗浄効果を十分に促進できないおそれがある。 The lower limit of the average height of the head spaces 9a, 9b, 9c is the average height of the filtration chambers 4a, 4b, 4c (the average of the lower partition plates 3a, 3b, 3c and the upper partition plates 2a, 2b, 2c). 30% of the interval) is preferable, and 50% is more preferable. On the other hand, as an upper limit of the average height of the head spaces 9a, 9b, 9c, 80% of the average height of the filtration chambers 4a, 4b, 4c is preferable, and 70% is more preferable. When the average height of the head spaces 9a, 9b, 9c is less than the lower limit, the filtration particles 7a, 7b, 7c and the washing particles 8a, 8b, 8c cannot move sufficiently during backwashing, and the filtration particles 7a, 7b, There is a possibility that the cleaning effect of 7c cannot be sufficiently promoted. On the other hand, when the average height of the head spaces 9a, 9b, 9c exceeds the above upper limit, the space becomes too large, and the frequency with which the filtered particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c come into contact at the time of back washing is increased. There exists a possibility that the washing | cleaning effect of filtration particle | grains 7a, 7b, 7c cannot fully be accelerated | stimulated by becoming small.
［水処理方法］
　続いて、図１の下向流式濾過塔を用いた水処理方法について説明する。 [Water treatment method]
Then, the water treatment method using the downward flow type filtration tower of FIG. 1 is demonstrated.
　図１の下向流式濾過塔を用いた水処理方法は、濾過室４ａ，４ｂ，４ｃにおいて被処理液を濾過する濾過工程と、濾過室４ａ，４ｂ，４ｃの濾過粒子７ａ，７ｂ，７ｃを洗浄する逆洗工程と、濾過室４ａ，４ｂ，４ｃ内に濾過粒子７ａ，７ｂ，７ｃの層を形成する濾過層形成工程とを繰り返す。 The water treatment method using the downward flow type filtration tower in FIG. 1 includes a filtration step of filtering the liquid to be treated in the filtration chambers 4a, 4b, 4c, and filtration particles 7a, 7b, 7c in the filtration chambers 4a, 4b, 4c. And a filtration layer forming step of forming layers of filtration particles 7a, 7b, 7c in the filtration chambers 4a, 4b, 4c are repeated.
＜濾過工程＞
　上記濾過工程は、被処理液供給流路５から被処理液を供給し、被処理液を濾過した処理済液を処理済液排出流路６から排出する。この濾過工程において、濾過室４ａ，４ｂ，４ｃ内には、下側仕切板３ａ，３ｂ，３ｃの上に洗浄粒子８ａ，８ｂ，８ｃの層が形成され、洗浄粒子８ａ，８ｂ，８ｃの層の上に濾過粒子７ａ，７ｂ，７ｃにより濾過層が形成され、濾過層と上側仕切板２ａ，２ｂ，２ｃとの間にはヘッドスペース９ａ，９ｂ，９ｃが形成された状態とされる。 <Filtering process>
In the filtration step, the liquid to be processed is supplied from the liquid supply path 5 to be processed, and the processed liquid obtained by filtering the liquid to be processed is discharged from the liquid discharge path 6 for processed liquid. In this filtration step, layers of cleaning particles 8a, 8b, 8c are formed on the lower partition plates 3a, 3b, 3c in the filtration chambers 4a, 4b, 4c, and layers of cleaning particles 8a, 8b, 8c are formed. A filtration layer is formed by filtration particles 7a, 7b, and 7c on the top, and head spaces 9a, 9b, and 9c are formed between the filtration layer and the upper partition plates 2a, 2b, and 2c.
　被処理液の供給方法は特に限定されず、例えばポンプによる圧送、水頭による自然流下等の方法を用いることができる。 The supply method of the liquid to be treated is not particularly limited, and for example, a method such as pumping by a pump or natural flow by a water head can be used.
　下向流式濾過塔を用いた水処理方法における下向流式濾過塔の単位断面積当たりの被処理液の供給量の下限としては、１００ｍ３／ｍ２・ｄａｙが好ましく、３００ｍ３／ｍ２・ｄａｙがより好ましい。一方、上記被処理液の供給量の上限としては、特に限定されないが、３０００ｍ３／ｍ２・ｄａｙが好ましく、１０００ｍ３／ｍ２・ｄａｙがより好ましい。上記被処理液の供給量が上記下限に満たない場合、大量に被処理液が発生する環境下で処理能力が不足するおそれや、多数の下向流式濾過塔が必要となるおそれがある。逆に、上記被処理液の供給量が上記上限を超える場合、逆洗工程の頻度が大きくなり、非効率となるおそれがある。 The lower limit of the supply amount of the liquid to be treated per unit cross-sectional area of the downward flow filtration tower in the water treatment method using the downward flow filtration tower is preferably 100 m 3 / m 2 · day, and 300 m 3 / m. 2 · day is more preferable. In contrast, the upper limit of the feed rate of the liquid to be treated is not particularly limited, but is preferably 3000m 3 / m 2 · day, more preferably 1000m 3 / m 2 · day. When the supply amount of the liquid to be processed is less than the lower limit, there is a risk that the processing capacity may be insufficient in an environment where a large amount of liquid to be processed is generated, or a large number of downflow filtration towers may be required. On the contrary, when the supply amount of the liquid to be treated exceeds the upper limit, the frequency of the backwashing process is increased, which may be inefficient.
　濾過工程において、濾過粒子７ａ，７ｂ，７ｃの各層により分離された油分や濁質は、多くが複数の濾過粒子７ａ，７ｂ，７ｃの間に保持されるが、一部がヘッドスペース９ａ，９ｂ，９ｃ及びその上の空間（濾過室４ａ，４ｂ，４ｃの外側の空間）に滞留（浮上分離）する。 In the filtration step, most of the oil and turbidity separated by the layers of the filtration particles 7a, 7b, and 7c are retained between the plurality of filtration particles 7a, 7b, and 7c, but some of the head spaces 9a, 9b are retained. 9c and the space above it (the space outside the filtration chambers 4a, 4b, 4c).
　図１の下向流式濾過塔を用いた水処理方法で回収した処理済液の濁質濃度の上限としては、１０ｐｐｍが好ましく、５ｐｐｍがより好ましく、３ｐｐｍがさらに好ましく、１ｐｐｍが特に好ましい。処理済液の濁質濃度が上記上限を超える場合、処理済液を環境に負荷を与えず廃棄することや産業用水として利用することができないおそれがある。ここで、「濁質濃度」とは、浮遊物質（ＳＳ）の濃度を意味し、ＪＩＳ－Ｋ０１０２（２００８）の「１４．１　懸濁物質」に準拠して測定される値である。 The upper limit of the turbidity concentration of the treated liquid recovered by the water treatment method using the downward flow filtration tower in FIG. 1 is preferably 10 ppm, more preferably 5 ppm, further preferably 3 ppm, and particularly preferably 1 ppm. When the turbidity concentration of the treated liquid exceeds the above upper limit, the treated liquid may not be disposed of without causing a load on the environment or may not be used as industrial water. Here, “turbidity concentration” means the concentration of suspended solids (SS), and is a value measured according to “14.1 suspended matter” of JIS-K0102 (2008).
　図１の下向流式濾過塔を用いた水処理方法で回収した処理済液の油濃度の上限としては、１００ｐｐｍが好ましく、１０ｐｐｍがより好ましく、１ｐｐｍがさらに好ましい。処理済液の油濃度が上記上限を超える場合、下向流式濾過塔の下流で行う油水分離処理の負荷が過大となるおそれや、処理済液を環境に負荷を与えず廃棄することができなくなるおそれがある。 The upper limit of the oil concentration of the treated liquid recovered by the water treatment method using the downward flow filtration tower in FIG. 1 is preferably 100 ppm, more preferably 10 ppm, and even more preferably 1 ppm. If the oil concentration of the treated liquid exceeds the above upper limit, the load of the oil / water separation treatment downstream of the downflow filtration tower may be excessive, or the treated liquid can be discarded without causing any environmental load. There is a risk of disappearing.
＜逆洗工程＞
　上記逆洗工程では、処理済液排出流路６から洗浄水を供給し、濾過室４ａ，４ｂ，４ｃを通過し、濾過粒子７ａ，７ｂ，７ｃから分離した油分や濁質並びに濾過室４ａ，４ｂ，４ｃのヘッドスペース９ａ，９ｂ，９ｃ及びその上の筒状本体１内の空間に滞留していた油分や濁質を含む洗浄廃水を被処理液供給流路５から排出する。なお、この洗浄廃水は、次の濾過工程において、被処理液の一部として被処理液供給流路５に供給してもよい。 <Backwash process>
In the backwashing step, washing water is supplied from the treated liquid discharge flow path 6, passes through the filtration chambers 4a, 4b, and 4c, and the oil and turbidity separated from the filtration particles 7a, 7b, and 7c, and the filtration chamber 4a, Washing wastewater containing oil and turbidity remaining in the space in the cylindrical main body 1 and the head spaces 9a, 9b, 9c of 4b, 4c is discharged from the liquid supply passage 5 to be treated. In addition, this washing waste water may be supplied to the liquid to be processed supply channel 5 as a part of the liquid to be processed in the next filtration step.
　下から上に向かって流れる洗浄水は、先ず洗浄粒子を舞い上がらせ、油分や濁質で固まった濾過粒子７ａ，７ｂ，７ｃの層を割りほぐして濾過粒子７ａ，７ｂ，７ｃが洗浄水によってヘッドスペース９ａ，９ｂ，９ｃに舞い上げられるようにする。ヘッドスペース９ａ，９ｂ，９ｃに舞い上げられた濾過粒子７ａ，７ｂ，７ｃは、洗浄水中で撹拌されることによって付着した油分や濁質が剥離される。また、舞い上げられた濾過粒子７ａ，７ｂ，７ｃは、他の濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃとぶつかり合うことにより、付着した油分や濁質の剥離が促進される。 The washing water flowing from the bottom to the top first causes the washing particles to rise, breaks the layers of the filtration particles 7a, 7b, and 7c solidified by oil and turbidity, and the filtration particles 7a, 7b, and 7c become the headspace by the washing water. 9a, 9b, 9c can be raised. The filtered particles 7a, 7b, and 7c raised in the head spaces 9a, 9b, and 9c are agitated in the washing water, and the attached oil and turbidity are peeled off. Further, the raised filter particles 7a, 7b, 7c collide with the other filter particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c, thereby promoting the separation of the attached oil and turbidity. .
　上記逆洗工程は、一定時間毎に行われてもよく、上記濾過工程において被処理液供給流路５と処理済液排出流路６との圧力差が一定の圧力に達したときや、被処理液供給流路５又は処理済液排出流路６の流量が一定の流量に低下したときに行ってもよく、オペレターの操作により行われてもよい。 The backwashing step may be performed at regular intervals. When the pressure difference between the liquid supply channel 5 to be processed and the liquid discharge channel 6 to be processed reaches a constant pressure in the filtration step, It may be performed when the flow rate of the processing liquid supply flow path 5 or the processed liquid discharge flow path 6 is reduced to a constant flow rate, or may be performed by operating an operator.
　下向流式濾過塔の単位断面積当たりの洗浄水の給水量としては、例えば２００Ｌ／ｍ２・ｈｒ以上２０００Ｌ／ｍ２・ｈｒ以下とすることができる。 The amount of wash water supplied per unit cross-sectional area of the downward flow filtration tower can be, for example, 200 L / m 2 · hr or more and 2000 L / m 2 · hr or less.
　また、逆洗時間としては、例えば３０秒以上１０分以下とすることができる。また、一定時間毎に逆洗を行う場合の逆洗の間隔としては、例えば１時間以上１２時間以下とすることができる。 Also, the backwash time can be, for example, 30 seconds to 10 minutes. Moreover, as an interval of backwashing when backwashing is performed every predetermined time, it can be set to 1 hour or more and 12 hours or less, for example.
　供給する洗浄水としては、市水や濾過工程において処理済液排出流路６から排出された処理済み液を使用することができる。また、洗浄水は気泡を混入したバブリングジェット水流として供給されることが好ましい。バブリングジェット水流は、例えばバブリングジェット装置、エダクタ等を用いて製造することができる。バブリングジェット水流を使用することによって、気泡により濾過粒子７ａ，７ｂ，７ｃからの油分や濁質の剥離を促進できる。また、洗浄水は気泡を含まないジェット水流として供給してもよい。 As the wash water to be supplied, city water or the treated liquid discharged from the treated liquid discharge flow path 6 in the filtration step can be used. The washing water is preferably supplied as a bubbling jet water stream in which bubbles are mixed. The bubbling jet water stream can be produced using, for example, a bubbling jet device, an eductor, or the like. By using a bubbling jet water stream, it is possible to promote separation of oil and turbidity from the filtered particles 7a, 7b, and 7c by bubbles. Further, the washing water may be supplied as a jet water stream that does not contain bubbles.
　バブリングジェット水流中の空気量（常温大気圧における容積の水の体積に対する比）としては、例えば１ＮＬ／Ｌ以上５ＮＬ／Ｌ以下が好ましい。また、バブリングジェット水流中の気泡の平均径としては、１ｍｍ以上４ｍｍ以下が好ましい。さらに、洗浄水の送水圧としては、０．２ＭＰａ以上が好ましく、バブリングジェット水流の流速としては、例えばバブリングジェットノズルの吐出口において２０ｍ／ｓ以上が好ましい。 The amount of air in the bubbling jet water flow (ratio of the volume of water at room temperature and atmospheric pressure to the volume of water) is preferably, for example, from 1 NL / L to 5 NL / L. Moreover, as an average diameter of the bubble in a bubbling jet water flow, 1 mm or more and 4 mm or less are preferable. Further, the feed pressure of the washing water is preferably 0.2 MPa or more, and the flow rate of the bubbling jet water flow is preferably 20 m / s or more at the outlet of the bubbling jet nozzle, for example.
＜濾過層形成工程＞
　濾過層形成工程では、濾過室４ａ，４ｂ，４ｃ内を水で満たした状態とし、濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃを自然沈降させる。この時、平均比重及び平均粒径が大きい洗浄粒子８ａ，８ｂ，８ｃは、沈降速度が大きく、先に沈降して下側仕切板３ａ，３ｂ，３ｃの上に層を形成する。洗浄粒子８ａ，８ｂ，８ｃよりも平均比重及び平均粒径が小さく、沈降速度が小さい濾過粒子７ａ，７ｂ，７ｃは、先に形成された洗浄粒子８ａ，８ｂ，８ｃの層の上に降り積もって濾過層を形成する。 <Filter layer forming step>
In the filtration layer forming step, the filtration chambers 4a, 4b and 4c are filled with water, and the filtration particles 7a, 7b and 7c and the washing particles 8a, 8b and 8c are naturally settled. At this time, the cleaning particles 8a, 8b, and 8c having a large average specific gravity and a large average particle diameter have a high sedimentation speed, and settle first to form a layer on the lower partition plates 3a, 3b, and 3c. Filter particles 7a, 7b, and 7c having a smaller average specific gravity and average particle diameter and lower settling velocity than cleaning particles 8a, 8b, and 8c are deposited on the previously formed layer of cleaning particles 8a, 8b, and 8c. A filtration layer is formed.
　濾過層形成工程の最初（逆洗工程終了時）に、処理済液排出流路６から空気を含まない水を逆洗工程の洗浄水の流量以上の流量で供給し、濾過室４ａ，４ｂ，４ｃ内を水で満たし、かつ濾過粒子７ａ，７ｂ，７ｃ及び洗浄粒子８ａ，８ｂ，８ｃを上側仕切板２ａ，２ｂ，２ｃに押し付けるようにすれば、洗浄粒子８ａ，８ｂ，８ｃと濾過粒子７ａ，７ｂ，７ｃとの分離を促進することができる。 At the beginning of the filtration layer forming step (at the end of the backwashing step), water containing no air is supplied from the treated liquid discharge flow path 6 at a flow rate that is equal to or higher than the flow rate of the washing water in the backwashing step. If the inside of 4c is filled with water and the filtering particles 7a, 7b, 7c and the cleaning particles 8a, 8b, 8c are pressed against the upper partition plates 2a, 2b, 2c, the cleaning particles 8a, 8b, 8c and the filtering particles 7a , 7b, 7c can be promoted.
［利点］
　当該下向流式濾過塔は、濾過粒子７ａ，７ｂ，７ｃと洗浄粒子８ａ，８ｂ，８ｃとが充填される複数の濾過室４ａ，４ｂ，４ｃを備え、上側の濾過室ほど平均粒径及び平均比重が大きい洗浄粒子が充填されていることによって、油分や濁質の濃度が高い上側の濾過室ほど洗浄粒子の沈降速度が大きいので、上側の濾過室ほど粒径が大きく沈降速度が大きい濾過粒子を使用することができる。つまり、当該下向流式濾過塔は、上側の濾過室ほど濾過粒子の平均粒径を大きくして、目詰まりを起こし難くすると共に、下側ほど濾過粒子の平均粒径を小さくして、より小さい油分や濁質を取り除くことができる。また、当該下向流式濾過塔は、各濾過室にそれぞれ洗浄粒子を充填したので、逆洗時に洗浄粒子によって油分や濁質で固まった濾過粒子の層を割りほぐして濾過粒子を迅速に洗浄することができる。 [advantage]
The downflow filtration tower includes a plurality of filtration chambers 4a, 4b, and 4c filled with filtration particles 7a, 7b, and 7c and cleaning particles 8a, 8b, and 8c. Since the upper filtration chamber with a higher concentration of oil and turbidity has a higher sedimentation rate of the cleaning particles because it is filled with cleaning particles having a higher average specific gravity, the upper filtration chamber has a larger particle size and a larger sedimentation rate. Particles can be used. That is, the downflow type filtration tower increases the average particle size of the filtration particles in the upper filtration chamber so that clogging is less likely to occur, and decreases the average particle size of the filtration particles in the lower side. Small oil and turbidity can be removed. In addition, since the downflow type filtration tower is filled with cleaning particles in each filtration chamber, the filter particles are quickly washed by breaking the layer of filter particles solidified with oil or turbidity by the washing particles during backwashing. be able to.
［その他の実施形態］
　今回開示された実施の形態は全ての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は、上記実施形態の構成に限定されるものではなく、特許請求の範囲によって示され、特許請求の範囲と均等の意味及び範囲内での全ての変更が含まれることが意図される。 [Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. The
　下向流式濾過塔に配設される濾過室の数は、特に限定されず、２以上の任意の数とすることができる。 The number of filtration chambers disposed in the downward flow filtration tower is not particularly limited, and can be any number of 2 or more.
　また、濾過室は、例えば多孔セラミックス、織布、不織布、繊維、活性炭等の油用吸着材を有するユニットと併用してもよい。油用吸着材ユニットは、濾過室よりも下流側に配設されることが好ましい。 The filtration chamber may be used in combination with a unit having an adsorbent for oil such as porous ceramics, woven fabric, non-woven fabric, fiber, activated carbon or the like. The oil adsorbent unit is preferably disposed downstream of the filtration chamber.
　また、濾過室は、濾過粒子及び洗浄粒子の上にヘッドスペースが形成されないものであってもよい。 Further, the filtration chamber may be one in which no head space is formed on the filtration particles and the washing particles.
　また、筒状本体の側部に、各濾過室の下方に洗浄水をそれぞれ供給する複数の給水路を設けてもよく、各濾過室の上方から洗浄廃水をそれぞれ排出する複数の排水路を設けてもよい。上記濾過室の下方に洗浄水を供給する給水路は、下側仕切板の下側面に向かって洗浄水を吐出するノズルを有してもよい。このようなノズルを設けることにより、濾過室内に少なくとも部分的に流速の大きい流れを形成し、洗浄粒子によって濾過粒子の層を割りほぐす効果を促進することができる。また、ノズルは、濾過粒子又は洗浄粒子の層の中に埋没するよう配置し、洗浄水の水圧を直接作用させて濾過粒子や洗浄粒子の層を割りほぐすようにしてもよい。 In addition, a plurality of water supply passages for supplying washing water to the lower side of each filtration chamber may be provided on the side of the cylindrical body, and a plurality of drainage channels for discharging washing wastewater from above each filtration chamber are provided. May be. The water supply path for supplying the cleaning water to the lower side of the filtration chamber may have a nozzle that discharges the cleaning water toward the lower surface of the lower partition plate. By providing such a nozzle, a flow having a high flow velocity can be formed at least partially in the filtration chamber, and the effect of breaking the layer of filtration particles with the cleaning particles can be promoted. Further, the nozzle may be disposed so as to be buried in a layer of filtration particles or cleaning particles, and a layer of filtration particles or cleaning particles may be broken by directly acting the water pressure of the cleaning water.
　また、濾過室には、下側仕切板を通して洗浄水を供給するのに加えて、定常状態において形成されるヘッドスペースの位置に側方から洗浄水を供給するようにしてもよい。濾過室のヘッドスペースの位置に供給され、下方からの洗浄水とは異なる向きの流れを有する洗浄水によって、濾過粒子のもみ洗い効果を促進することができる。この濾過室の中に洗浄水を供給する流路は、濾過室の内部に突出し、下向きに開口するノズルを備えてもよい。このようなノズルを設けることにより、下降流を形成して濾過粒子の洗浄効果を促進できると共に、濾過粒子の層に対して流速の大きい洗浄水を衝突させて、濾過粒子の層を割りほぐすことができる。 In addition to supplying cleaning water to the filtration chamber through the lower partition plate, cleaning water may be supplied from the side to the position of the head space formed in the steady state. The scrubbing effect of the filtered particles can be promoted by the washing water supplied to the position of the head space of the filtration chamber and having a flow in a direction different from the washing water from below. The flow path for supplying cleaning water into the filtration chamber may include a nozzle that protrudes into the filtration chamber and opens downward. By providing such a nozzle, it is possible to promote the cleaning effect of the filtered particles by forming a downward flow, and to make the filtered particle layer break up by colliding with the cleaning particle having a large flow velocity against the filtered particle layer. it can.
　以上のように、当該下向流式濾過塔は、油田や工場で発生する被処理液から油分や濁質を除去するために好適に利用することができる。 As described above, the downflow filtration tower can be suitably used for removing oil and turbidity from the liquid to be treated generated in oil fields and factories.
１　筒状本体
２ａ，２ｂ，２ｃ　上側仕切板
３ａ，３ｂ，３ｃ　下側仕切板
４ａ，４ｂ，４ｃ　濾過室
５　被処理液供給流路
６　処理済液排出流路
７ａ，７ｂ，７ｃ　濾過粒子
８ａ，８ｂ，８ｃ　洗浄粒子
９ａ，９ｂ，９ｃ　ヘッドスペース DESCRIPTION OF SYMBOLS 1 Cylindrical main body 2a, 2b, 2c Upper side partition plates 3a, 3b, 3c Lower side partition plates 4a, 4b, 4c Filtration chamber 5 Processed liquid supply flow path 6 Processed liquid discharge flow paths 7a, 7b, 7c Filter particle 8a , 8b, 8c Cleaning particles 9a, 9b, 9c Headspace

Claims (6)

  1. 　複数の通水性の仕切板で区画される複数の濾過室を備える下向流式濾過塔であって、
    　上記複数の濾過室それぞれに濾過粒子と洗浄粒子とが充填され、
    　上記濾過室の洗浄粒子の平均粒径及び平均比重がその濾過室直下の濾過室の洗浄粒子よりも大きい下向流式濾過塔。     A downward flow filtration tower comprising a plurality of filtration chambers partitioned by a plurality of water-permeable partition plates,
    Each of the plurality of filtration chambers is filled with filtration particles and cleaning particles,
    A downflow filtration tower in which the average particle diameter and average specific gravity of the cleaning particles in the filtration chamber are larger than the cleaning particles in the filtration chamber immediately below the filtration chamber.
  2. 　上記濾過室の洗浄粒子の平均粒径が、その濾過室直下の濾過室の洗浄粒子の平均粒径の１．５倍以上１０倍以下である請求項１に記載の下向流式濾過塔。 The downflow filter tower according to claim 1, wherein the average particle size of the cleaning particles in the filtration chamber is 1.5 to 10 times the average particle size of the cleaning particles in the filtration chamber immediately below the filtration chamber.
  3. 　上記濾過室の洗浄粒子の平均比重が、その濾過室直下の濾過室の洗浄粒子の平均比重の１．１倍以上２倍以下である請求項１又は請求項２に記載の下向流式濾過塔。 The downflow filtration according to claim 1 or 2, wherein the average specific gravity of the cleaning particles in the filtration chamber is 1.1 to 2 times the average specific gravity of the cleaning particles in the filtration chamber immediately below the filtration chamber. Tower.
  4. 　上記濾過室の洗浄粒子の充填質量割合が、その濾過室直下の濾過室の洗浄粒子の充填質量割合よりも大きい請求項１、請求項２又は請求項３に記載の下向流式濾過塔。 The downflow type filtration tower according to claim 1, 2 or 3, wherein a washing mass ratio of the cleaning particles in the filtration chamber is larger than a filling mass ratio of the washing particles in the filtration chamber immediately below the filtration chamber.
  5. 　上記濾過室中の洗浄粒子の充填質量割合とその濾過室直下の濾過室の洗浄粒子の充填質量割合との差が、５％以上２０％以下である請求項４に記載の下向流式濾過塔。 5. The downward flow filtration according to claim 4, wherein a difference between a filling mass ratio of the cleaning particles in the filtration chamber and a filling mass ratio of the cleaning particles in the filtration chamber immediately below the filtration chamber is 5% or more and 20% or less. Tower.
  6. 　１の上記濾過室の洗浄粒子の平均粒径及び平均比重が同じ濾過室の濾過粒子よりも大きい請求項１から請求項５のいずれか１項に記載の下向流式濾過塔。 The downflow type filtration tower according to any one of claims 1 to 5, wherein an average particle diameter and an average specific gravity of the cleaning particles in the filtration chamber of 1 are larger than the filtration particles in the same filtration chamber.
PCT/JP2015/078559 2014-11-10 2015-10-08 Downflow-type filtration tower WO2016076042A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2015559368A JPWO2016076042A1 (en) 2014-11-10 2015-10-08 Downflow filter tower

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-228115 2014-11-10
JP2014228115 2014-11-10

Publications (1)

Publication Number Publication Date
WO2016076042A1 true WO2016076042A1 (en) 2016-05-19

Family

ID=55954134

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2015/078559 WO2016076042A1 (en) 2014-11-10 2015-10-08 Downflow-type filtration tower

Country Status (2)

Country Link
JP (1) JPWO2016076042A1 (en)
WO (1) WO2016076042A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109442621A (en) * 2018-11-02 2019-03-08 滁州市云米工业设计有限公司 A kind of industrial air cleaning unit and its working method
CN111111284A (en) * 2020-01-15 2020-05-08 张有兴 Oil field oil extraction wastewater treatment device and operation method

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1294880A (en) * 1969-03-10 1972-11-01
JPS5322664A (en) * 1976-08-16 1978-03-02 Nippon Zeon Co Complex filter layer
JPS53101381U (en) * 1977-01-20 1978-08-16
JPS56144712A (en) * 1980-04-15 1981-11-11 Hitachi Plant Eng & Constr Co Ltd Filter apparatus
JPS57107207A (en) * 1980-12-26 1982-07-03 Hitachi Plant Eng & Constr Co Ltd Method and device for filtering microsuspended solids
JPH0889726A (en) * 1994-09-27 1996-04-09 Matsushita Electric Ind Co Ltd Water purifying device
JP3037266U (en) * 1996-10-29 1997-05-16 バイタル・ジャパン株式会社 Filtration tank structure
JPH1199398A (en) * 1997-07-28 1999-04-13 Toto Ltd Septic tank
JP2013248563A (en) * 2012-05-31 2013-12-12 Kamata Bio Eng Kk Filtering device, filtering method of the same, and backwashing method of filter medium

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1294880A (en) * 1969-03-10 1972-11-01
JPS5322664A (en) * 1976-08-16 1978-03-02 Nippon Zeon Co Complex filter layer
JPS53101381U (en) * 1977-01-20 1978-08-16
JPS56144712A (en) * 1980-04-15 1981-11-11 Hitachi Plant Eng & Constr Co Ltd Filter apparatus
JPS57107207A (en) * 1980-12-26 1982-07-03 Hitachi Plant Eng & Constr Co Ltd Method and device for filtering microsuspended solids
JPH0889726A (en) * 1994-09-27 1996-04-09 Matsushita Electric Ind Co Ltd Water purifying device
JP3037266U (en) * 1996-10-29 1997-05-16 バイタル・ジャパン株式会社 Filtration tank structure
JPH1199398A (en) * 1997-07-28 1999-04-13 Toto Ltd Septic tank
JP2013248563A (en) * 2012-05-31 2013-12-12 Kamata Bio Eng Kk Filtering device, filtering method of the same, and backwashing method of filter medium

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109442621A (en) * 2018-11-02 2019-03-08 滁州市云米工业设计有限公司 A kind of industrial air cleaning unit and its working method
CN109442621B (en) * 2018-11-02 2020-09-08 苏州德粤通风机电设备有限公司 Industrial air purification device and working method thereof
CN111111284A (en) * 2020-01-15 2020-05-08 张有兴 Oil field oil extraction wastewater treatment device and operation method

Also Published As

Publication number Publication date
JPWO2016076042A1 (en) 2017-08-17

Similar Documents

Publication Publication Date Title
CA2576034C (en) Method and apparatus for increasing filter contaminant loading capacity
TWI548443B (en) An unshaped filter layer and a filter device provided with the filter layer
CA2738015C (en) Water filter apparatus incorporating walnut shell filter media and a draft tube system
JP5117433B2 (en) Waste water adsorption equipment
ES2937166T3 (en) Multilayer Media Bed Filter with Enhanced Backwash
WO2015079923A1 (en) Water treatment device and water treatment method using same
US20160340209A1 (en) Water treatment apparatus and water treatment method using the same
KR100930545B1 (en) Upflow Manganese Contact Tower
EP3459611B1 (en) Filter module for a liquid purification device
WO2016076042A1 (en) Downflow-type filtration tower
WO2015156118A1 (en) Oil-water separation treatment system and oil-water separation treatment method
WO2016038948A1 (en) Filtration unit
WO2016075773A1 (en) Water treatment device and water treatment method using same
WO2016092643A1 (en) Oil-water separation system, oil-water separation method, and spiral separation membrane element
JP2001507279A (en) Method and apparatus for continuously filtering liquid
JP5742032B2 (en) Filtration device
JP2014226604A (en) Water treatment equipment and water treatment method using the same
JP5831698B2 (en) Filtration device
JP5754649B2 (en) Depth filtration equipment
EP2859928B1 (en) Method for filter backwashing
JP2016215138A (en) Silt filter device and silt filter method

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2015559368

Country of ref document: JP

Kind code of ref document: A

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15858268

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15858268

Country of ref document: EP

Kind code of ref document: A1