WO2017122678A1

WO2017122678A1 - Air diffusion device and air diffusion hole cover

Info

Publication number: WO2017122678A1
Application number: PCT/JP2017/000631
Authority: WO
Inventors: 龍夫梅田; 康光平山; 守生益崎; 達哉増永
Original assignee: 三井造船環境エンジニアリング株式会社
Priority date: 2016-01-12
Filing date: 2017-01-11
Publication date: 2017-07-20
Also published as: JP6335401B2; JPWO2017122678A1

Abstract

The present invention addresses the problem of providing, at a low cost, an air diffusion device and an air diffusion hole cover, which prevent blockage of a pipe due to sludge, etc., which render washing of an air diffusion pipe unnecessary, and which enable stable air diffusion. The problem is solved by comprising: an air diffusion pipe 30 having a plurality of air diffusion holes at the lower end; a front surface plate 310 and a back surface plate 311 which are opposingly aligned so as to tightly touch both side surfaces of the air diffusion pipe 30 and which extend below the lower end of the air diffusion pipe 30; and an upstream side partition plate 312 and a downstream side partition plate 313 for sealing openings formed on the upstream side and the downstream side of the front surface plate 310 and the back surface plate 311, and further comprising, below the air diffusion pipe 30, an air diffusion hole cover 31 having an open bottom and formed of the front surface plate 310, the back surface plate 311, the upstream side partition plate 312, and the downstream side partition plate 313, wherein a plurality of vertical slits 317 are arranged along the air diffusion pipe 30 at respective lower parts of the front surface plate 310 and the back surface plate 311 constituting the air diffusion hole cover 31, and a space is formed between the lower end of the air diffusion pipe 30 and an air-liquid interface so that the air-liquid interface is located at least 5 mm away from the lower end of the air diffusion pipe 30 but within the area of the plurality of vertical slits 317.

Description

Air diffuser and air diffuser cover

The present invention relates to an air diffuser and an air diffuser cover, and more particularly to an air diffuser and an air diffuser cover that can prevent clogging due to sludge and the like and do not require cleaning of the air diffuser.

Conventionally, in the aeration tank of the activated sludge treatment apparatus, an aeration tube having a plurality of aeration nozzles attached to supply air is provided. The air diffuser is immersed in the bottom of the aeration tank, and bubbles are ejected from the air diffuser nozzle to supply oxygen to the activated sludge. Moreover, the air supplied from the bottom part of the aeration tank stirs the activated sludge and plays a role of increasing the contact efficiency between the raw water to be treated and the activated sludge.

Also known is a solid-liquid separation device that immerses the submerged membrane separation device in a solid-liquid separation tank to separate the activated sludge from the treated water. Since this submerged membrane separator is a solid-liquid separation by membrane filtration, clean treated water can be obtained stably, but there is a problem that the membrane is clogged. In order to suppress the occurrence of clogging of such a membrane separator, a method of aeration from below the membrane separator is employed.

Japanese Patent No. 3382926 Japanese Patent Laid-Open No. 10-66834

Conventionally, Patent Document 1 discloses an air diffuser in which an air diffuser is arranged below a membrane separator, bubbles are extracted from the diffuser, and the membrane is cleaned by rising bubbles. A diffuser tube used in the diffuser is provided with a plurality of diffuser holes.

However, in the case of this air diffuser, the air diffuser becomes a gas-liquid interface, and sludge enters and exits the air diffuser. The sludge that has entered the diffuser pipe is dried by the diffused air and fixed to the inner surface of the pipe. The adhered sludge needs to be cleaned periodically by the pulsation due to the air lift effect by opening the valve at the end of the diffuser pipe raised up above the liquid level of the water tank in which the membrane separator is installed.

Further, Patent Document 2 discloses an air diffuser in which a bottom portion is opened and an air diffuser such as a slit is provided on a side surface.

However, according to FIG. 1 of Patent Document 2, a plurality of connection ports are provided in one air feeding header, and an aeration apparatus is provided in each of the connection ports. For this reason, there is a problem that the aeration apparatus is required by the number of connection ports, which increases the cost.

¡In the length direction of one air supply header, the amount of air discharged from each connection port may not be uniform. For example, there is a problem that the air discharge amount increases at the central portion of the air supply header or the air discharge amount pulsates as a whole.

Therefore, an object of the present invention is to provide an air diffuser and an air diffuser cover that do not block piping due to sludge and the like, do not need to clean an air diffuser, enable stable air diffuser, and reduce costs.

Other problems of the present invention will become apparent from the following description.

The above problems are solved by the following inventions.

(Claim 1)
(A) an air diffuser having a plurality of air diffusers at the lower end;
(B) A front plate and a back plate that are arranged side by side so as to be in close contact with both side surfaces of the air diffuser and extend downward from the lower end of the air diffuser, and upstream of the front plate and the back plate An upstream partition plate and a downstream partition plate that seal openings formed on the side and the downstream side, and below the diffuser tube, the front plate and the back plate, and the upstream partition plate and the downstream It consists of an air diffuser cover whose bottom is released by a side partition plate,
A plurality of vertical slits are provided in parallel in the direction along the air diffuser at the lower part of each of the front plate and the back plate constituting the air diffuser cover of (B),
A space is provided between the lower end of the diffuser tube and the gas-liquid interface so as to have a gas-liquid interface at a position that is at least 5 mm away from the lower end of the diffuser tube and in the range of the plurality of slits in the vertical direction. An air diffuser characterized by being formed.
(Claim 2)
The air diffuser according to claim 1, wherein an interval between the front plate and the back plate is configured to become narrower downward.
(Claim 3)
The front plate and the back plate are opposed to each other, and the upstream partition plate and the downstream partition plate are opposed to each other.
The cylindrical body has an open top and bottom,
At the upper part of each of the upstream partition plate and the downstream partition plate, a notch corresponding to the outer shape of the diffuser pipe is provided,
A diffuser cover, wherein a plurality of vertical slits are formed in the lower part of each of the front plate and the back plate.
(Claim 4)
The air diffuser cover according to claim 3, wherein an interval between the front plate and the back plate facing each other is configured to become narrower downward.

According to the present invention, it is possible to provide an air diffuser and an air diffuser cover that do not block the piping due to sludge and the like, enable stable air diffusion, do not need to clean the air diffuser, and reduce costs.

The figure which shows embodiment using an example of the aeration apparatus of this invention The figure which looked at the diffuser in FIG. 1 from the lower part The perspective view which shows the diffuser hole cover in embodiment of this invention Sectional drawing of the diffuser which shows the driving | running state in embodiment of this invention The figure which looked at the state where an example of the diffuser of the present invention was immersed in the water tank from the bottom of the water tank The figure which shows the aspect in which the diffuser cover is divided into five blocks The figure which shows the aspect by which the membrane separator was comprised by five membrane modules The figure which shows the aspect by which the membrane separator installation part and the diffuser installation part are provided

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an embodiment using an example of an air diffuser according to the present invention.
Reference numeral 1 denotes a water tank, 2 denotes a membrane separator immersed in the

water tank

1, and 3 denotes an air diffuser installed below the membrane separator 2. 4 is a blower for aeration.

The water tank 1 is not particularly limited as long as it is a water tank that needs to be diffused. For example, an aeration tank employed for activated sludge treatment may be used. In this case, if the diffuser 3 is installed in the aeration tank, the stirring air can be supplied into the aeration tank, and oxygen can be supplied to the activated sludge.

Also, if a membrane separation device is installed in the aeration tank, it is excellent in that a solid-liquid separation tank such as a precipitation tank can be omitted. When installing a membrane separation apparatus in an aeration tank, an aeration tank can be provided in multistage and a membrane separation apparatus can be provided in the last stage aeration tank.

If the air diffuser 3 is installed below the membrane separator to raise the bubbles, it can contribute to membrane cleaning of the membrane separator.

Examples of the membrane used in the membrane separation device 2 include a microfiltration membrane and an ultrafiltration membrane, and the membrane form may be either a flat membrane type or a tubular type.

The air diffuser 3 includes an air diffuser tube 30 having a plurality of air diffuser holes at the lower end, and an air diffuser cover 31 below the air diffuser tube 30. The air diffuser cover 31 is formed to extend downward from the lower end of the air diffuser 30.

The air diffuser 30 has, for example, a plurality of air diffusers 300 as shown in FIG. 2 is a view of the air diffuser in FIG. 1 as viewed from below. In the illustrated example, one diffuser hole cover 31 is provided for two

diffuser holes

300, 300.

The air diffuser cover 31 includes a front plate 310 and a back plate 311 that are arranged side by side so as to closely face both side surfaces of the air diffuser as shown in FIG.

312 and 313 are an upstream partition plate and a downstream partition plate that seal openings formed on the upstream side and the downstream side of the front plate 310 and the back plate 311. The upstream partition plate 312 and the downstream partition plate 313 are opposed to each other.

The front plate 310 and the back plate 311 face each other, the upstream partition plate 312 and the downstream partition plate 313 face each other, and the front plate 310 and the back plate 311 touch the upstream partition plate 312 and the downstream partition plate 313. By being provided orthogonally, the air diffuser cover 31 is formed in a rectangular cylindrical body. The upper and bottom portions of the cylindrical air diffuser cover 31 are open, 314 is an opening in the bottom portion, and 315 is an opening in the upper portion.

The front plate 310 and the back plate 311 are juxtaposed so as to closely face both side surfaces of the air diffuser 30. Here, close contact means that the air in the space 316 formed by the lower portion of the diffuser tube 30 and the diffuser hole cover 31 is in contact with the lower slit 317 so as to ensure airtightness from leaking outside. is there.

Examples of the means for intimate contact include welding (welding) or adhesion. For example, when the front plate 310 and the back plate 311 are formed of a resin plate such as vinyl chloride, the resin plate can be welded to be fixed to the intermediate outer periphery of the air diffusion tube 3.

The upstream side partition plate 312 and the downstream side partition plate 313 are preferably formed integrally with the front plate 310 and the back plate 311 so as to ensure airtightness in the space 316.

It is preferable to form the front plate 310 and the back plate 311 so as to be inclined inward and to have a narrow width as shown in FIGS. This is to prevent air from leaking from the bottom of the air diffuser cover 31. By causing pressure loss with respect to the air pressure of the air discharged from the air diffuser 300 of the air diffuser 30, it is possible to prevent the gas-liquid interface from being easily lowered to the bottom and to prevent leakage.

A cutout corresponding to the outer shape of the air diffuser tube 30 is formed in the upper part of the upstream divider plate 312 and the downstream divider plate 313, and the cutout is in contact with the air diffuser tube 30 to ensure the airtightness in the space 316. It has become so. The shape of the notch is not particularly limited as long as it corresponds to the outer shape of the air diffusing tube 30.

The diffuser tube 30, the front plate 310, the back plate 311, the upstream partition plate 312, and the downstream partition plate 313 are preferably formed using a resin plate such as polyethylene, polypropylene, vinyl chloride, or acrylic resin.

A plurality of slits 317 arranged in parallel below the front plate 310 and the back plate 311 are formed in the vertical direction in the direction along the air diffuser 30.

The width of the slit 317 is preferably in the range of 4 to 12 mm, and the length is preferably in the range of 15 to 30 mm.

That is, as shown in FIG. 4, the lower end of the air diffuser 30 (the part of the air diffuser 300) is A, the upper end of the slit 317 is B1, and the lower end of the slit 317 (the lower end of the front plate 310 and the back plate 311) is B2. In some cases, the slit 317 is formed at a position at least 5 mm away from the lower end A of the air diffuser 30. By forming in this way, the gas-liquid interface W is formed in the range from B1 to B2, which is the area range of the slit 317 in the vertical direction. The aforementioned space 316 is formed between the lower end of the air diffuser 30 and the gas-liquid interface W. The air diffuser 300 may be provided slightly shifted from the lower end of the air diffuser 30 to the left or right in the circumferential direction. In this case, A is the lowest part of the air diffusion hole 300.

In the air diffuser shown in FIG. 1, when air is supplied from the blower 4 to the air diffuser 30, air is sent from the air diffuser 300 to the space 316 in the air diffuser cover 31.

The pressure of the air supplied into the space 316 is adjusted so that the gas-liquid interface W can be maintained at a predetermined position.

The gas-liquid interface W is formed in a range from B1 to B2, which is a region range of the vertical slit 317. By doing in this way, the air supplied in the space 316 becomes a bubble from the slit and is discharged to the outside, and effectively functions for agitation in the aeration tank, oxygen supply, and membrane cleaning of the upper membrane separation device. .

The formation of the gas-liquid interface W as described above has an effect of avoiding the situation where air is discharged from the lower part of the space 316 and the situation where bubbles cannot be formed.

By forming the slit 317 at a position at least 5 mm away from the lower end A of the air diffuser 30, the gas-liquid interface W is formed as described above. As a result, sludge and the like are formed in the space 316. Even if splashes, since it is away from the air holes, it is possible to prevent sludge from adhering to the air holes.

In the preferred embodiment of the present invention, the bottom of the air diffuser cover 31 is released. Since the gas-liquid interface W is in the range of the slit by releasing the bottom, even if sludge adheres to the slit due to the liquid in the water tank, drying of the sludge can be prevented. As a result, accumulation of sludge and the like can be prevented, and the clogging of the slit can be prevented.

Furthermore, by maintaining the air pressure in the space 316 to such an extent that no leakage is diffused from the bottom, pulsation can be prevented and stable aeration can be achieved.

In this embodiment, the air diffuser cover 31 is in a form that hangs downward from the side surface of the air diffuser tube 30, and is not a form that is provided at the tip of a single air diffuser nozzle as in the prior art. The air diffuser cover 31 is formed with a space 316 that receives air ejected from one or more air diffusers.

In the example shown in the figure, air is supplied to the space 316 from the two

air holes

300, 300. However, if one air hole cover 31 is provided for each of a certain number of air holes, Due to the orifice effect of the air diffuser hole itself, the air pressure of the air diffuser 30 is reduced by the pressure loss, and the pressure in the space 316 can be kept uniform.

On the other hand, when a single air diffuser is provided for a single connection port as in the prior art, there is no orifice effect of the air diffuser, and the amount of air diffused in the length direction of the air supply header There is a problem that pulsation of the overall air volume occurs.

Next, another embodiment of the present invention will be described.
5 to 8 show other embodiments of the present invention.
In this embodiment, an air diffuser is installed near the bottom of the water tank, a membrane separator is provided on the air diffuser, and both the air diffuser and the membrane separator are immersed in water.

As shown in FIG. 8, the water tank 1 is provided with a membrane separation device installation site 2A and an air diffusion device installation site 3A, and the membrane separation device 2 and the air diffusion device shown in FIGS. 3 is installed.

FIG. 5 is a view of an example of the diffuser of the present invention immersed in a water tank as viewed from below the water tank. The air diffusing device 3 shown in the figure has a configuration in which two

air diffusing tubes

30 and 30 are connected from a header tube 30A.

Below the air diffuser 30, as shown in FIG. 6, one air diffuser cover 31 is provided for the two

air diffusers

300, 300, which are divided into five blocks as a whole. A membrane module 20 constituting the membrane separation device 2 is disposed above.

FIG. 7 shows an embodiment of the membrane separation device 2 configured with five membrane modules. In the figure, 20 is a membrane module of the

membrane separation device

2, and 21 is a suction header tube. *

The permeated water sucked from the membrane module 20 is sent to the suction holes 210, 210,... Via a hose (indicated by reference numeral 22 in FIG. 8), and collected in the suction header pipe 21 to obtain permeated water.

In the above embodiment, the membrane separation device is constituted by five membrane modules, but the number is not limited, and the number can be increased or decreased according to the target permeated water amount. Further, if the membrane area of one membrane separation device is increased, the number of installed membrane separation devices can be reduced.

In the present invention, bubbles are generated from the air diffusing device 3 to clean the upper film and the air diffusing device itself does not need to be cleaned, so that the cleaning equipment and the cleaning work can be omitted.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to the examples.

Example 1
As shown in FIG. 1, an air diffuser 30 having a plurality of air diffuser holes at the lower end and a diffuser cover 31 welded to the lower part of the air diffuser pipe 30 is manufactured, and an air diffuser test is performed. .
As shown in FIG. 2, the air diffuser 30 has a plurality of air diffusers at the lower end.
As shown in FIG. 3, the air diffuser cover 31 is arranged in parallel so as to be in close contact with both side surfaces of the air diffuser, and extends downward from the lower end of the air diffuser. The upstream partition plate 312 and the downstream partition plate 313 seal the openings formed on the upstream side and the downstream side of the front plate 310 and the back plate 311.
The air diffuser 30 and the air diffuser cover 31 were designed to satisfy the following specifications.
(Air diffuser)
Aeration amount: approx. 1,600 L / min Material: Vinyl chloride Number: 2 Sizes: Pipe diameter x length = 50 mm x approx. 1,900 mm
Air diffuser: Hole diameter 20 mm, 10 holes / piece (see FIG. 5)
(Air diffuser cover)
Material: Vinyl chloride Number of air diffuser covers: 5 blocks / piece; 1 air diffuser cover for 2 diffuser holes (see Fig. 6)
Number of slits: 12 locations per diffuser cover; 6 locations on the front plate, 6 locations on the back plate (see FIG. 3)
Slit: upper end semicircular shape; width 6mm, length 20mm
Gas-liquid interface: a position 5 mm or more away from the lower end of the diffuser (see Fig. 4)

(Test conditions)
Tests were conducted in principle for 24 hours (excluding equipment inspection and chemical cleaning of membranes) for aeration of solid-liquid separation membranes in activated sludge treatment at the sludge recycling treatment center in the Kyushu area. The test period was about 14 months.

As a result, it was not necessary to subject the air diffuser to cleaning with air or water during the test period. This is because even if the sludge is scattered, the configuration as described above does not cause a problem that the sludge adheres to the air holes and slits and is blocked.
Further, since the pulsation was prevented by maintaining the air pressure in the air diffuser cover, there was no bias in the amount of air diffused, and stable air diffusion could be performed.
Moreover, in the prior test, in the above apparatus, when the gas-liquid interface is less than 5 mm from the lower end of the diffuser tube, the above-described stable aeration cannot be performed.

1: Water tank 2: Membrane separator 20: Membrane module 21: Suction header pipe 210: Suction hole 22: Hose 3: Air diffuser 30A: Header pipe 30: Air diffuser pipe 300: Air diffuser hole 31: Air diffuser cover 310: Front plate 311: Back plate 312: Upstream partition plate 313: Downstream partition plate 314, 315: Opening 316: Space 317: Slit 4: Blower

Claims

(A) an air diffuser having a plurality of air diffusers at the lower end;
(B) A front plate and a back plate that are arranged side by side so as to be in close contact with both side surfaces of the air diffuser and extend downward from the lower end of the air diffuser, and upstream of the front plate and the back plate An upstream partition plate and a downstream partition plate that seal openings formed on the side and the downstream side, and below the diffuser tube, the front plate and the back plate, and the upstream partition plate and the downstream It consists of an air diffuser cover whose bottom is released by a side partition plate,
A plurality of vertical slits are provided in parallel in the direction along the air diffuser at the lower part of each of the front plate and the back plate constituting the air diffuser cover of (B),
A space is provided between the lower end of the diffuser tube and the gas-liquid interface so as to have a gas-liquid interface at a position that is at least 5 mm away from the lower end of the diffuser tube and in the range of the plurality of slits in the vertical direction. An air diffuser characterized by being formed.
The air diffuser according to claim 1, wherein an interval between the front plate and the back plate is configured to become narrower downward.
The front plate and the back plate are opposed to each other, and the upstream partition plate and the downstream partition plate are opposed to each other.
The cylindrical body has an open top and bottom,
At the upper part of each of the upstream partition plate and the downstream partition plate, a notch corresponding to the outer shape of the diffuser pipe is provided,
A diffuser cover, wherein a plurality of vertical slits are formed in the lower part of each of the front plate and the back plate.
The air diffuser cover according to claim 3, wherein an interval between the front plate and the back plate facing each other is configured to become narrower downward.