JP2939095B2 - Methane fermentation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methane fermentation apparatus.

[0002]

2. Description of the Related Art Conventionally, various methods for treating organic wastewater have been provided. In the case of the activated sludge treatment method, microorganisms such as bacteria and protozoa are cultured in an aeration tank. Aeration for 4-8 hours to give oxygen,
Activated sludge is generated. When organic wastewater is supplied to the aeration tank as raw water, the microorganisms eat organic matter in the raw water and purify the raw water.

However, according to the activated sludge treatment method, a large amount of air needs to be supplied to the aeration tank, and a power unit for supplying the air is required, which not only increases the size of the apparatus but also increases the cost. turn into. Therefore, an anaerobic treatment method for treating the raw water by methane fermentation has been provided. For example, in the case of a methane fermentation device,
Raw water is supplied to the fermenter, and methane gas is generated and treated by methane bacteria. in this case,
A stirring (stirring) device is arranged to constantly stir the raw water in the fermenter.

FIG. 2 is a sectional view of a conventional gas lift type methane fermentation apparatus, and FIG. 3 is a sectional view of a conventional screw pump type methane fermentation apparatus. In FIG. 2, 1 is a fermenter for storing raw water, 2 is a draft tube arranged in the fermenter 1 in a vertical direction, and 3 is a draft tube 2
The injection ports 4 for injecting draft gas into the draft tube 2 are blowers for injecting draft gas from the injection ports 3.

A methane bacterium is added to the raw water in the fermenter 1
Raw water is treated by the methane bacteria to generate methane gas and carbon dioxide gas. The methane gas and carbon dioxide gas are discharged from the discharge pipe 6 as generated gas. And the discharge pipe 6
Is communicated with the blower 4, a part of the gas generated in the discharge pipe 6 is sucked by the blower 4, and is injected into the draft tube 2 from the injection port 3 as a draft gas.

The draft gas is supplied to the draft tube 2
When it is injected into the draft tube, it rises, and at this time, the raw water in the draft tube 2 is also raised. Thus, the raw water in the fermenter 1 is stirred by the draft gas rising in the draft tube 2. In FIG. 3, reference numeral 1 denotes a fermenter for storing raw water, 2 denotes a draft tube disposed in the fermenter 1 in a vertical direction, 8 denotes an upper end of the draft tube 2, and 8 denotes a draft tube. This is a pump that sucks raw water.

A methane bacterium is added to the raw water in the fermenter 1,
Raw water is treated by the methane bacteria to generate methane gas and carbon dioxide gas. The methane gas and carbon dioxide gas are discharged from the discharge pipe 6 as generated gas. Thus, the raw water in the fermenter 1 can be stirred by driving the pump 8.

[0008]

However, in the conventional methane fermentation apparatus, a part of the raw water in the fermenter 1 is stirred by the draft gas or the pump 8, so that the stirring power is weak, and Not only cannot be sufficiently stirred, but also the processing time becomes long. The present invention solves the problems of the conventional methane fermentation apparatus, and provides a methane fermentation apparatus capable of increasing stirring power, sufficiently stirring raw water, and shortening the treatment time. Aim.

[0009]

For this purpose, in the methane fermentation apparatus of the present invention, a tank maintained in an anaerobic state, a multiplicity of porous disks disposed in the tank, and a tank disposed at the upper end of the tank are provided. A driving device for raising and lowering the multi-hole disk, and means for supplying raw water to the tank.

[0010] In another methane fermentation apparatus of the present invention,
The driving device raises and lowers the perforated disk at 10 to 80 [cpm].

[0011]

According to the present invention, in the methane fermentation apparatus as described above, a tank maintained in an anaerobic state, a number of perforated disks provided in the tank, and a tank provided at the upper end of the tank. A drive for raising and lowering the perforated disk; and means for supplying raw water to the tank.

[0012] Therefore, when raw water is supplied to the tank and methane bacteria are added, the methane bacteria are used to remove organic matter,
Organic solids and the like are anaerobically processed to generate methane gas and carbon dioxide gas. Then, the driving device is operated,
The raw water can be stirred by raising and lowering the porous disk. In this case, since the perforated disk is disposed over the entire inside of the tank, the whole raw water in the tank is simultaneously stirred, and the efficiency of stirring can be improved.

[0013] In another methane fermentation apparatus of the present invention,
The driving device raises and lowers the perforated disk at 10 to 80 [cpm].

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 is a schematic diagram of a processing system using a methane fermentation apparatus showing an embodiment of the present invention, FIG. 4 is a cross-sectional view of a methane fermentation apparatus showing an embodiment of the present invention, and FIG. 5 is methane showing an embodiment of the present invention. It is an enlarged view of a fermentation apparatus.

In the figure, reference numeral 10 denotes a processing system,
The treatment system 10 includes a methane fermentation device 11, a liquid / gas separation device 13, and a sedimentation (chin) tank 15, treats raw water, and discharges treated water to a treatment tank (not shown). The methane fermentation apparatus 11 has a multiplicity of porous disks 18 which are repeatedly raised and lowered at regular intervals in a cylindrical tank 17, and the porous disks 18 are fixed to a shaft 21 at regular intervals. Each of the porous disks 18 has a plurality of through holes 18a. And
A driving device 22 is provided at the upper end of the shaft 21, and the porous disk 18 can be moved up and down via the shaft 21 by operating the driving device 22. In this embodiment, the through holes 18a of the perforated disks 18 are formed at the same position for all the perforated disks 18, but are formed at different positions for each adjacent perforated disk 18, so-called "staggered foot".
They may be arranged in a shape.

The driving device 22 includes a motor 22a fixed to the upper end of the tank 17 and a crank mechanism 23 which is operated by the motor 22a and converts the rotational motion into a reciprocating motion and transmits the reciprocating motion to the shaft 21. Having. Lines 24 and 25 are connected to the lower end of the tank 17, and raw water is supplied to the tank 17 by driving the pump P1. In addition, methane bacteria are added to the raw water, and the methane bacteria are used to anaerobically treat organic substances and organic solids in the raw water to generate methane gas and carbon dioxide gas.

The raw water can be agitated by operating the driving device 22 to raise and lower the porous disk 18 via the shaft 21. In this case, since the perforated disk 18 is disposed all over the tank 17, the whole raw water in the tank 17 is stirred at the same time, and the efficiency of stirring can be improved.

A line 26 for discharging a mixed liquid of treated water, methane gas, carbon dioxide gas or the like is connected to the upper end of the tank 17. Supplied to The line 24 is connected to the sedimentation tank 15,
A line 31 for returning a part of the sludge settled in 5 to the tank 17 as return sludge is connected. Note that the line 31 is provided with a pump P2.

The tank 17 has a line 25 and a line 2
The raw water supplied through the line 4 and the return sludge returned through the lines 31 and 24 are supplied to the tank 1 from the lower end.
7 flows into. Then, in the tank 17, since the porous disk 18 is repeatedly raised and lowered, a vortex (vortex) is formed around the porous disk 18, and a flow like a jet flow is generated. In this case, since the perforated disk 18 is disposed over the entire inside of the tank 17 as described above, a jet flow is generated in the tank 17,
Raw water can be vigorously stirred.

As a result, the organic matter (especially organic solid matter) in the raw water and the methane bacterium are in sufficient contact, and the decomposition of the organic matter (finally, CH ₄ + CO ₂ + H ₂ O) becomes very fast. In addition, the partially decomposed organic matter is subdivided by the shearing force of stirring, and is more easily decomposed. In response to this, a large amount of methane gas and carbon dioxide gas are generated, and these generated gases are quickly removed from the tank 17 as the porous disk 18 moves up and down. Never do.

On the other hand, the mixture discharged from the tank 17 has many bubbles. Therefore, a liquid-gas separator 13 is provided to destroy bubbles generated in the tank 17, and the mixed liquid discharged through the line 26 is supplied to the liquid-gas separator 13. And the liquid-gas separation device 1
The mixed liquid after the bubbles are destroyed in 3 and the methane gas and the carbon dioxide gas are separated is supplied to the settling tank 15, and the sludge is settled in the settling tank 15 so that the treated water can be taken out. On the other hand, the separated generated gas is discharged from the discharge pipe 14.

A line 33 for supplying treated water to the settling tank 15 and a line 34 for discharging settled sludge are connected to the settling tank 15, and the line 34 further transfers returned sludge to the tank 17. It is connected to a line 31 for returning and a line 35 for discharging excess sludge out of the system. Note that a pump P3 is provided on the line 35. Accordingly, the sludge from which the treated water has been separated in the settling tank 15 is discharged through the line 34, flows through the line 31 as returned sludge, returns through the line 24 to the tank 17, and removes the methane bacteria in the tank 17 from the sludge. refill. On the other hand, the remaining excess sludge is discharged out of the system via the line 35 and disposed.

Next, a description will be given of experimental results obtained by comparing the treatment by the methane fermentation apparatus 11 of the present invention with the treatment by the conventional methane fermentation apparatus. FIG. 6 is a conceptual diagram of a test machine using a conventional methane fermentation device, and FIG. 7 is a conceptual diagram of a methane fermentation device showing an embodiment of the present invention. In FIG. 6, 1 is a fermenter, 41 is a motor, 42 is a stirring blade rotated by the motor 41, 43 is a line for supplying raw water to the fermenter 1, and 44 is a line for discharging generated gas. And 45 are gas holders for storing generated gas.

In FIG. 7, reference numeral 17 denotes a tank;
Is a perforated disk, 22a is a motor, 24 is the tank 1
7 is a line for supplying raw water, 44 is a line for discharging generated gas, and 45 is a gas holder for storing the generated gas. In the experiment, fermenter 1 and tank 17 were used.
In each case, those having an effective capacity of 5 [l] were used, and 1,500 [ml] of the sewage sludge having the properties shown in Table 1 was batch-injected and treated.

[0025]

[Table 1]

As shown in Table 2, the stirring conditions of the conventional fermenter 1 were such that the rotation speed of the stirring blade 42 was 100 [rpm].
m], and the stirring condition of the tank 17 of the present invention is such that the number of times of lifting and lowering the porous disk 18 is 5 [cpm], 10 [cpm],
The values were 20 cpm, 40 cpm, and 80 cpm. Note that cpm indicates the number of cycles per minute.

[0027]

[Table 2]

The effect of the treatment was determined by measuring the amount of methane gas generated. FIG. 8 is a diagram showing the transition of the amount of generated methane gas. In the figure, the horizontal axis indicates the number of treatment days, and the vertical axis indicates the amount of methane gas generated. As shown in FIG.
(FIG. 7), the number of times the porous disc 18 was raised and lowered was 10
When it is set to [cpm] or more, the generation amount of methane gas increases and the generation speed also increases. The generation rate of the methane gas becomes maximum when the number of times the porous disk 18 is raised and lowered is about 40 [cpm]. From this, the multi-hole disc 1
It can be seen that the processing speed is increased when the number of elevations of 8 is 10 to 80 [cpm].

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0030]

As described above in detail, according to the present invention, in the methane fermentation apparatus, a tank maintained in an anaerobic state, a large number of porous disks disposed in the tank, A drive device is provided at an upper end for raising and lowering the perforated disk, and has means for supplying raw water to the tank.

Therefore, when the raw water is supplied to the tank and methane bacteria are added, the methane bacteria will cause the organic matter in the raw water,
Organic solids and the like are anaerobically processed to generate methane gas and carbon dioxide gas. Then, the driving device is operated,
The raw water can be stirred by raising and lowering the porous disk. In this case, since the perforated disk is disposed over the entire inside of the tank, the whole raw water in the tank is simultaneously stirred, and the efficiency of stirring can be improved.

Therefore, the raw water can be sufficiently stirred, and the processing time can be shortened. In another methane fermentation apparatus of the present invention, the driving device raises and lowers the porous disk at 10 to 80 [cpm]. In this case, the generation rate of methane gas can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a treatment system using a methane fermentation apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional gas lift methane fermentation apparatus.

FIG. 3 is a cross-sectional view of a conventional screw pump type methane fermentation apparatus.

FIG. 4 is a sectional view of a methane fermentation apparatus showing an embodiment of the present invention.

FIG. 5 is an enlarged view of a methane fermentation apparatus showing an embodiment of the present invention.

FIG. 6 is a conceptual diagram of a test machine using a conventional methane fermentation apparatus.

FIG. 7 is a conceptual diagram of a methane fermentation apparatus showing an embodiment of the present invention.

FIG. 8 is a diagram showing a change in the amount of generated methane gas.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Methane fermentation apparatus 17 Tank 18 Perforated disk 22 Drive 22a Motor 24, 25 line P1 pump

Claims (2)

(57) [Claims] 1. A tank maintained in an anaerobic state,
(B) a number of perforated disks arranged in the tank;
(C) A methane fermentation apparatus, comprising: a driving device provided at an upper end of the tank for raising and lowering the porous disc; and (d) means for supplying raw water to the tank. 2. The driving device according to claim 1, wherein the driving device drives
The methane fermentation apparatus according to claim 1, wherein the methane fermentation apparatus is moved up and down at 80 [cpm].