JP2009202139A - Gas diffuser member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas diffuser member which can reduce electric power consumption of a blower by increasing oxygen distribution efficiency. <P>SOLUTION: A gas diffuser plate 1 (the gas diffuser member) comprises a porous ceramic member 19 having a plurality of through-holes 11 formed therethrough for passing a gas, and preferably further comprises: a hollow member which has an inner surface smoother than that of the through-hole 11 and is fixedly inserted into each of the through-holes 11; and a nozzle part for discharging the gas, which is connected to the through-hole 11 in such a way as to project from the surface of a porous ceramic member 10. The gas discharge side end of the nozzle part preferably has an outer diameter smaller than that of the gas discharge side end of the through-hole 11. The gas discharge opening of the through-hole 11 preferably has an inner diameter smaller than that of its gas inlet opening. The gas discharge opening of the hollow member preferably has an inner diameter smaller than that of its gas inlet opening. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an aeration member applied to a water treatment apparatus.

  In a water treatment apparatus in a water treatment plant or the like, a diffuser plate for distributing oxygen or ozone is disposed at the lower part of a reaction tank. The most common diffuser is a porous ceramic diffuser plate in which coarse ceramic particles are bonded with a binder or the like. Ceramic particles are often rectangular, circular or gravel, and the average particle diameter is generally about 0.5 to 2 mm in terms of the projected area equivalent diameter. In that case, the pore diameter is about 260 to 400 μm. As the size of the diffuser plate, a flat plate shape of 300 × 300 × 30 mm is widely used. The air distributed from the blower becomes fine bubbles through the diffuser and is discharged into the tank. In order to obtain a high dissolution efficiency by uniformly supplying air into the tank of the diffuser plate, it is required that the diameter of bubbles ejected from the diffuser plate be uniform and fine.

  The power required for the water treatment process accounts for about 30 to 60% of the total power consumption of the entire treatment facility, most of which is consumed by the blower for distributing oxygen necessary for water treatment in the tank. . During processing, the blower is always in operation to prevent the backflow of sewage to the diffuser, and the total power consumption at the treatment facilities installed nationwide is approximately the total power consumption used in Japan. It reaches 0.4%. This should be corrected from the viewpoint of power saving, energy saving and carbon dioxide saving. Moreover, with the recent advancement of sewage treatment, it is required to perform even nitrogen removal. In order to increase the amount of oxygen supplied to the treatment tank, a method of increasing the number of installed diffuser plates is simple, but there is a limit depending on the area of the treatment tank.

  Therefore, the development of a diffuser plate that can supply oxygen more efficiently into the treated water is an important issue in order to reduce power consumption and nitrification.

  In the porous diffuser plate, there are two methods for increasing the amount of oxygen delivered per diffuser plate: a method of reducing the generated bubble diameter and improving the oxygen dissolution efficiency, and a method of increasing the air flow rate and increasing the amount of oxygen delivered. Two types are possible. But the two are in conflict. That is, if the pore diameter of the diffuser plate is reduced in order to reduce the generated bubble diameter, the pressure loss increases and the air flow rate decreases. Further, when the air flow rate of the diffuser plate is increased while keeping the pore diameter of the diffuser plate constant, the bubble diameter increases and the oxygen dissolution efficiency per bubble decreases. Further, both of these methods require a blower with a large discharge pressure, and there is a problem that the operating cost increases as the power consumption increases. Therefore, there is a limit in increasing the amount of oxygen delivered by these methods.

  As a method of improving the air flow rate and air flow resistance in the diffuser plate, the wettability of the inner surface of the fine pores can be improved by modifying the surface characteristics to hydrophobic (non-polarized) on the surface of the casing where the fine pores open. There is a method of eliminating the formation of a water film by lowering and reducing the ventilation resistance (Patent Document 1). Further, there is a method of uniformly forming and arranging a large number of irregularities on the surface of a porous plate-like body (Patent Document 2). Furthermore, a so-called membrane-type air diffuser in which a large number of holes are arranged in a membrane-like rubber instead of a porous body has also been proposed (Patent Document 3).

However, it is not a significant improvement in the amount of ventilation and ventilation resistance. In addition, the diffuser plate using resin on the surface, the rubber film part in the membrane type diffuser, etc., have problems such as aging deterioration in sewage.
JP 2002-263679 A JP-A-9-164396 JP 2003-320388 A

  The present invention has been made in view of the above problems, and is to provide a diffuser plate that can improve the oxygen distribution efficiency to the treatment tanks related to the water treatment facility and reduce the power consumption of the blower.

  In the diffuser member for solving the above-mentioned problems, a plurality of through-holes through which a gas flows are formed in the porous ceramic member. According to the present invention, since a plurality of through holes are formed in the porous ceramic member, the pressure loss inside the ceramic member is reduced, and the air flow rate can be improved without increasing the generated bubble diameter.

  In the air diffusing member, a hollow member whose inner surface is smoother than the inner surface of the through hole may be inserted and fixed in the individual through holes. Since the inner surface of the hollow member is smoother than the inner surface of the through hole, the occurrence of turbulent flow of gas flowing through the hollow body member is reduced, and the pressure loss can be effectively reduced.

  In the air diffuser, the through hole is connected to an injection portion for releasing the gas so as to protrude from the surface of the porous ceramic member, and the injection portion has an outer diameter at the exhaust side end. It is good that it is smaller than the outer diameter of the exhaust side end. It is possible to reduce the area where bubbles are adsorbed to the injection unit, and the bubble diameter generated by the diffuser plate can be further reduced.

  In the air diffuser, the exhaust port portion of the through hole may have a smaller diameter than the intake port portion. In addition to the effect that a plurality of through-holes are formed in the porous ceramic member, it is possible to increase the air flow rate and reduce the generated bubble diameter.

  In the air diffusing member, the exhaust port portion of the hollow member may have a smaller diameter than the intake port portion. In addition to the action of the hollow member, it is possible to increase the air flow rate and reduce the generated bubble diameter.

  Therefore, according to the above invention, oxygen distribution efficiency improves and the power consumption of a blower reduces.

  Embodiments of the invention will be described with reference to the drawings. The diameter, the number, and the shape of the through holes in the diffuser plate according to the embodiment described below are determined by the required air flow rate, generated bubble diameter, and strength of the diffuser plate.

  FIG. 1 is a perspective view of a diffuser plate 1 according to a first embodiment of the invention. FIG. 2 is a schematic sectional view of the diffuser plate 1 showing the structure of the through holes 11 of the diffuser plate 1.

  The diffuser plate 1 is formed by forming a plurality of through holes 11 in a plate-like porous ceramic portion 10. In the porous ceramic portion 10, the average particle diameter of the ceramic particles is not particularly limited, but is about 0.1 to 3 mm, more preferably about 0.5 to 2 mm. As the average particle diameter, it is preferable to use a projected area equivalent diameter calculated by measuring the diameter of the particle at a plurality of positions with an optical microscope or a scanning electron microscope. More simply, a sieve diameter (for example, JIS R 6001 etc.) may be used. When the average particle size is about 0.5 to 2 mm, the pore size is about 260 to 400 μm. The diameter of the through hole is about 100 to 1000 μm, more preferably about 260 to 400 μm, which is the same as the pore diameter of the porous ceramic portion.

  Examples of the manufacturing method of the through hole 11 include casting, lost wax method, machining, and the like, and are not particularly limited. In order to efficiently dissolve oxygen with a constant foaming area, it is necessary to reduce the bubble diameter and avoid coalescence of the foamed gas. Therefore, it is preferable to manufacture the through holes 11 with a certain interval. The through hole 11 illustrated in FIG. 2 has a straight pipe structure, but the intake port 13 and the exhaust gas are exhausted like the through hole 12 shown in FIG. 3 in order to increase the air flow rate and reduce the generated bubble diameter. A structure in which the diameter of the mouth portion 14 is different (the inner diameter of the exhaust port portion 14 is smaller than the inner diameter of the air inlet portion 13), a so-called tapered structure may be adopted.

  FIG. 4 is a perspective view of the diffuser plate 2 according to the second embodiment. FIG. 5 is a schematic cross-sectional view of the diffuser plate 2 showing the structure of the hollow member 11 related to the diffuser plate 2.

  The diffuser plate 2 has a configuration in which a hollow member 21 is inserted into each through hole 11 of the porous ceramic portion 10 according to the first embodiment. The hollow member 21 is formed in a hollow pipe shape. The inner surface of the hollow member 21 is processed more smoothly than the inner surface of the through hole 11. Since the inner surface of the hollow member 21 is smooth, the turbulent flow of the passing gas is less generated and the pressure loss is lower than that of the through hole 11 of the diffuser plate 1 having a large unevenness on the inner surface. The material of the hollow member 21 is not particularly limited, such as ceramics, metal, resin, or wood, but ceramics, particularly dense ceramics for the purpose of preventing turbulent flow in the pipe, from the surface where the material is combined with the porous ceramic part 10. Is preferred. Although the hollow member 21 illustrated in FIG. 5 has a straight tube structure, an intake port portion 23 and an exhaust port portion are formed like the hollow member 22 shown in FIG. A structure having a different diameter from the diameter of 24 (the inner diameter of the exhaust port portion 24 is smaller than the inner diameter of the intake port portion 23), a so-called tapered structure member may be employed.

  FIG. 7 is a perspective view of the diffuser plate 3 according to the third embodiment of the invention. FIG. 8 is a longitudinal sectional view of the diffuser plate 3 provided with the nozzles 31. FIG. 9 is an enlarged cross-sectional view showing the configuration of the nozzle 31.

  As shown in FIGS. 7 and 8, the diffuser plate 3 is formed by connecting a nozzle 31 to the exhaust side of the through hole 11 of the porous ceramic portion 10 according to the first embodiment. The nozzle 31 is connected to the exhaust side of the through hole 11 so as to protrude from the surface of the porous ceramic portion 10. As shown in FIG. 9, the nozzle 31 has a structure of a different diameter pipe in which the exhaust port 35 has a smaller diameter than the intake port 32. A tapered air passage 33 communicating with the through hole 11 and a straight pipe air passage 34 communicating with the tapered air passage 33 are formed inside the nozzle 31. The discharge portion 36 of the nozzle 31 exposed from the diffuser plate 10 has an outer peripheral surface tapered. According to the nozzle 31, the generated bubble diameter can be reduced in the process from the intake port 32 to the exhaust port 35. Further, since the straight pipe ventilation path 34 is limited to the nozzle 31, it is possible to prevent an increase in pressure loss.

  FIG. 10A is a schematic diagram of generated bubbles in the discharge portion 37 having a straight pipe structure, and FIG. 10B is a schematic diagram of generated bubbles in the discharge portion 36 having a tapered structure. As is clear from these schematic diagrams, the generated bubble diameter depends on the outer diameter of the discharge portion of the nozzle. That is, the discharge part 37 whose outer diameter is larger than that of the discharge part 36 has a generated bubble diameter R1 larger than a generated bubble diameter R2 of the discharge part 36. Accordingly, when the outer peripheral surface is formed in a tapered shape like the discharge portion 36 shown in FIG. 10B, the area of bubbles adsorbed to the discharge portion is reduced, and the generated bubble diameter can be reduced.

  FIG. 11 is a schematic diagram illustrating the action of the diffuser plate 3 provided with the nozzles 31 when depositing sludge. Even when sludge (s) is deposited on the porous ceramic portion 10, aeration can be performed from the nozzle 31. Further, it is possible to peel the sludge (s) from the porous ceramic portion 10 by increasing the air flow rate and generating an upward flow (t) in the vicinity of the nozzle 31.

  Moreover, although the through-hole 11 of the diffuser plate 3 shown in FIG. 8 has a straight pipe structure, the through-hole 11 of the diffuser plate 4 shown in FIG. A structure in which the diameter of the intake port portion 42 and the diameter of the exhaust port portion 43 are different from each other like the hole 41 may be adopted.

  Since the diffuser plate according to the invention described above has a through-hole inside, the pressure loss inside the diffuser plate is reduced, and the air flow rate can be greatly improved without increasing the generated bubble diameter.

  Moreover, by having a through hole and a porous material, it is possible to control the ventilation performance and the generated bubble diameter, and to control the ventilation mode. By combining through holes and porous parts that have different ventilation behaviors, for example, “aeration only from the through hole during normal operation, aeration from the entire surface during blower strong wind” or “aeration from the entire surface during normal operation, penetration through when the blower is weak. It is possible to manufacture a diffuser plate having various ventilation forms such as “aeration only from the hole”.

  Examples of the diffuser plate according to the invention are shown below. However, the technical scope of the invention is not limited by the examples disclosed below.

The porous ceramic parts of the diffuser plates according to Example 1, Example 2 and Example 3 are prepared by mixing ceramic particles having an average particle diameter of 500-100 μm in projected area equivalent diameter with a binder, and then firing the mixture. did. The dry aeration rate in a differential pressure of 0.49 kPa and a ventilation path of 30 mm was about 188 ml / cm ² · min.

FIG. 13 is an enlarged photograph of the exhaust surface of the diffuser plate according to the first embodiment. The diffuser plate according to Example 1 is based on the diffuser plate 1 of the first embodiment described with reference to FIGS. 1 and 2. The through hole 11 was set to have a diameter of about 700 μm. The through holes 11 were formed at a rate of 4.13 per square centimeter with respect to the upper surface of the porous ceramic portion 10. The dry aeration rate in a differential pressure of 0.49 kPa and a ventilation path of 30 mm was about 2200 ml / cm ² · min.

FIG. 14 is an enlarged photograph of the exhaust surface of the diffuser plate according to the second embodiment. The diffuser plate according to Example 2 is based on the diffuser plate 2 of the second embodiment described with reference to FIGS. 4 and 5. The hollow member 21 is a pipe having an outer diameter of 1000 μm and an inner diameter of 400 μm. The hollow members 21 were arranged at a rate of 4.13 per square centimeter with respect to the upper surface of the porous ceramic portion 10. The dry air flow rate at a differential pressure of 0.49 kPa and a ventilation path of 30 mm was about 675 ml / cm ² · min.

FIG. 15 is an enlarged photograph of the exhaust surface of the diffuser plate according to the third embodiment. The diffuser plate according to Example 3 is based on the diffuser plate 3 of the third embodiment described with reference to FIGS. 7 and 8. The through hole 11 was set to a diameter of about 1000 μm. The nozzle 31 connected to the exhaust side of the through hole 11 is a ceramic nozzle having a minimum inner diameter of about 100 μm. It was produced at a rate of 2.07 per square centimeter with respect to the upper surface of the porous ceramic part 10. The dry air flow rate at a differential pressure of 0.49 kPa and an air flow path of 30 mm was about 350 ml / cm ² · min. When the generated bubbles of the hollow member 21 according to Example 2 and the generated bubbles of the nozzle 31 according to Example 3 were compared, the use of the nozzle 31 reduced the bubble diameter to about one fifth.

The perspective view of the diffuser plate which concerns on 1st embodiment of invention. The schematic sectional drawing of the diffuser plate which showed the structure of the through-hole which concerns on 1st embodiment of invention. The longitudinal cross-sectional view of the diffuser plate which showed the structure of the taper type through-hole. The perspective view of the diffuser plate which concerns on 2nd embodiment of invention. The schematic sectional drawing of the diffuser plate which showed the structure of the hollow member which concerns on 2nd embodiment of invention. The longitudinal cross-sectional view of the diffuser plate which showed the structure of the taper-type hollow member. The perspective view of the diffuser plate which concerns on 3rd embodiment of invention. The longitudinal cross-sectional view of the diffuser plate which concerns on 3rd embodiment provided with the nozzle. The expanded sectional view of the nozzle which concerns on 3rd embodiment. (A) The schematic diagram of the bubble produced | generated of a straight pipe | tube type discharge part, (b) The schematic diagram of the bubble produced | generated of a taper type discharge part. The schematic diagram explaining the effect | action at the time of sludge deposition of the diffuser board provided with the nozzle. The longitudinal cross-sectional view of the diffuser board which has a nozzle and the taper-type through-hole connected to this in an exhaust port part. The enlarged photograph of the exhaust surface of the diffuser plate which concerns on Example 1. FIG. The enlarged photograph of the exhaust surface of the diffuser plate which concerns on Example 2. FIG. The enlarged photograph of the exhaust surface of the diffuser plate which concerns on Example 3. FIG.

Explanation of symbols

1, 2, 3 ... Diffusing plate 10 ... Porous ceramic parts 11, 12, ... Through holes 21, 22 ... Hollow member 31 ... Nozzle (injection part)

Claims (5)

  An air diffusing member, wherein a plurality of through holes through which a gas flows are formed in a porous ceramic member.   The air diffusing member according to claim 1, wherein a hollow member whose inner surface is smoother than the inner surface of the through hole is inserted and fixed in the individual through hole. The through-hole is connected so that an injection part for releasing the gas protrudes from the surface of the porous ceramic member,
The diffuser member according to claim 1, wherein an outer diameter of an exhaust side end portion of the injection unit is smaller than an outer diameter of an exhaust side end portion of the through hole.   The diffuser member according to any one of claims 1 to 3, wherein an inner diameter of the exhaust port portion of the through hole is smaller than an inner diameter of the intake port portion.   The air diffuser according to claim 2, wherein the hollow member has an inner diameter of an exhaust port portion smaller than an inner diameter of the intake port portion.