JPH11197696A - Methane fermentation tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a methane fermentation purifying tank capable of executing the purifying treatment of org. matter containing excretion or the like at low operation cost by an anaerobic methane fermentation purifying method. SOLUTION: A methane fermentation tank 1 has a hermetically closed structure and is constituted so as to have a gas storage part storing gas generated by methane fermentation therein and storing the same in the upper part thereof and a jet pipe 2 of which the end part piercing the ceiling of the gas storage part to protrude downwardly and positioned in the gas storage part has a horizontal cut opening flat surface and the other end part is arranged up to the outside of the methane fermentation tank. By this constitution, by the mutual action of the gas pressure in the gas storage part and the surface tension of the treated soln. 3, a phenomenon wherein a treated soln. 3, scum 4 and formed gas are integrated to periodically repeating injection accompanied by an impact like an intermittent fountain is generated. The periodic removal of scum 4 generated in the fermentation tank 1 by impact jet energy becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anaerobic fermentation purification system for treating organic waste from the livestock industry and the like.
The present invention relates to a methane fermentation tank used in the anaerobic fermentation system.

[0002]

2. Description of the Related Art In recent years, treatment of organic waste such as manure in the livestock industry has become a serious problem. Emissions that do not use septic tank facilities and the like cause odor generation, polluting livestock such as rivers, groundwater, and marine pollution, and adversely affecting the surrounding environment.

[0003] Therefore, there is a long-awaited demand for an inexpensive and easy-to-maintain manure treatment facility which can be borne by a livestock farmer. Has been proposed.

[0004] The basic process of this methane fermentation treatment is, as shown in Fig. 4, mainly for a methane fermentation tank, for pretreatment of input waste, maintenance of fermenter operation conditions, and utilization and post-treatment of products. Consists of related equipment. In the pretreatment, operations such as removal of sediment and contaminants mixed in the input waste, control of temperature, pH, concentration, flow rate, and the like, addition of nutrients, and removal of inhibitory substances are performed as necessary. The fermenter is equipped with facilities necessary for temperature control, agitation, and control of digestion sludge concentration. In the post-processing, processing and utilization facilities are installed for each of the gas, liquid, and solid systems of the generated gas, the processing liquid, and the scum.

The most characteristic feature of methane fermentation is that thermal energy can be extracted as combustible gas from liquid or muddy organic waste having a high water content in a simple process. Also,
Although it is not possible to compare aerobic treatment with activated sludge and anaerobic methane fermentation treatment as the same method for treating organic waste on the same basis, the activated sludge method consumes power for aeration, but the methane fermentation method does not. Since no ventilation power is required, the power consumption is reduced to about 1/10, and the generated gas is recovered as fuel gas, which can be said to be an energy saving process.

[0006]

On the other hand, when organic waste mixed with livestock dung and the like is treated in the above-mentioned methane fermentation tank, wood and hair, etc., in the feed that does not decompose may become liquid level in the tank. To form a scum layer, which is a film of impurities.
If you do not remove the scum layer, it gradually thickens and solidifies,
As a result, the circulation of the processing solution was hindered and the methane fermentation tank was broken.

However, due to the configuration of the anaerobic methane fermentation purification system, the methane fermentation tank body has a closed structure to prevent anaerobic methane bacteria used inside the fermentation tank from coming into contact with the outside air, and only scum is removed. It was difficult to do. As a countermeasure, a method of preventing the formation of a scum layer by stirring the inside of the methane fermentation tank with an external power has been proposed, but in this case, this stirring power must be operated at all times, so that the operation cost is high and practical use is required. There was a problem that was not. Therefore, conventionally, when a methane fermentation tank is used, feces, which are a cause of scum, are removed, and the methane fermentation tank is used only for treating urine and washing water.

[0008] In view of the above problems, the present invention makes it possible to prevent the formation of a scum layer at low operating costs without stirring by external power, and more specifically, to dispose of waste containing feces by a methane fermentation method. It is an object of the present invention to provide a methane fermentation septic tank that enables practical use of material treatment.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is specifically constituted as follows.

First, the present invention is applied to a methane fermentation tank used in an anaerobic fermentation purification system for treating organic waste from the livestock industry or the like. And the invention of claim 1 is
The methane fermentation tank has a hermetic structure, a gas storage section for storing gas generated by methane fermentation inside thereof, and a gas storage section that projects downward through a ceiling of the gas storage section and further projects downward. And an ejection pipe arranged at the other end to the outside of the methane fermentation tank. With this configuration, the interaction between the gas pressure stored in the gas storage unit and the surface tension of the processing liquid causes the processing liquid
A phenomenon occurs in which scum and generated gas are united and jetting with a shock is periodically repeated like a geyser (hereinafter, this phenomenon is referred to as a geyser phenomenon). Then, the scum generated inside the fermenter can be periodically removed by the shocking ejection energy.

Next, a second aspect of the present invention is the first aspect.
A separation tank having a closed structure is installed outside the methane fermentation tank described above, and a gas collection pipe is connected to a relatively upper part of the separation tank, and a gas collection pipe is connected to a relatively lower part of the separation tank so as to communicate with the inside of the methane fermentation tank. And an outer end of the ejection pipe is connected to an arbitrary position of the separation tank.

[0012] With this configuration, the scum, the processing liquid, and the generated gas that are integrally ejected due to the geyser phenomenon are separated in the separation tank by their respective specific gravities, and thereafter the generated gas is collected by the gas collection. The liquor is absorbed into the tube, and the processing liquid is returned to the inside of the methane fermentation tank through the reflux tube, and the scum is deposited in the separation tank so as to be easily removed.

Next, a third aspect of the present invention is directed to the first aspect.
In the methane fermentation tank described in the above, by enclosing the outer end of the ejection pipe, the ejection gas is received to absorb the generated gas generated / floating from the ejection pipe, and the processing liquid and the scum as the residue are discharged to the outside by their own weight. A gas collecting pipe having a scum / processing liquid discharge port and a lower part of the gas collecting pipe where the scum / processing liquid discharge port is located, so that the processing liquid and the scum which are the residues are received and settled downward. A scum stationary tank having a reflux pipe for sucking and returning the treatment liquid into the methane fermentation tank.

With this configuration, the separation of the generated gas from the ejected material and the separation of the processing liquid are performed separately, so that efficient separation becomes possible. Next, according to a fourth aspect of the present invention, in the methane fermentation tank according to any one of the first to third aspects, the ceiling of the gas storage unit is inclined such that the periphery of the connection part of the ejection pipe is at the highest position. Configuration. With this configuration, the geyser phenomenon can be generated more frequently, and the scum in the fermenter can be efficiently removed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining the principle of the geyser phenomenon generated by the configuration of the first aspect of the present invention.

In this figure, a gas storage portion provided inside the methane fermentation tank 1 main body is integrated with the ceiling of the methane fermentation tank 1 main body, and the ejection pipe 2 penetrates the ceiling of the methane fermentation tank 1. And first, as shown in FIG.
A waste treatment liquid 3 to be purified is filled almost completely in the methane fermentation tank 1 through an inlet (not shown) in the methane fermentation tank 1.

After that, methane fermentation is performed in the processing liquid 3 to generate and float a generated gas such as methane gas, and a gas layer is formed in the upper part of the methane fermentation tank 1 as shown in FIG. . At this time, the processing liquid 3 moves into the ejection pipe 2 and is pushed up by the volume of the pressure of the gas layer (P in the figure) that has pushed down the level of the processing liquid 3. At this time, the scum layer 4 which does not decompose simultaneously on the surface of the processing liquid 3
Is formed.

As shown in FIG. 1 (c), even when the liquid level of the gas pressure is lowered and the liquid level drops to a position below the inner end of the jet pipe 2, immediately after that, The surface tension of the processing liquid 3 is generated around the end, and the flow of the generated gas 8 into and out of the ejection pipe 2 is not performed for a while. At this time, the weight of the processing liquid 3 pushed up by the height H in the ejection pipe 2 by the gas pressure and the processing liquid 3 around the inner end of the ejection pipe 2
Is in equilibrium with the gas pressure that presses the liquid surface of the gas layer. Further, it is preferable that the inner end of the ejection pipe 2 is substantially horizontal for generating the surface tension of the processing liquid 3.

Further, at the moment when the generation of gas in the processing liquid 3 progresses and the gas pressure in the upper gas layer exceeds this equilibrium state, a large amount of high-pressure gas flows into the jet pipe 2 at one time, and until then the jet pipe 2 The scum 4 and the processing liquid 3 which were inside are united and ejected with impact (FIG. 1).
(D)). At this time, the scum 4 and the processing liquid 3 on the liquid surface of the processing liquid 3 around the inner end of the jet pipe 2 are also jetted along with the inflow of the high-pressure gas around the inner end of the jetting pipe 2, and as a result, the airtightness inside the methane fermenter 1 is maintained. The scum 4 is removed as it is.

After a certain amount of ejection is performed, the processing liquid 3 is returned or the processing liquid 3 is replenished as described later,
The state returns to the state of (b), and the geyser phenomenon described above is repeatedly performed. This phenomenon is repeated at regular time intervals, and requires no special power and energy except for heating the methane fermentation tank 1 for methane fermentation, so it can be said that this is an energy-saving process.

Further, by isolating the periphery of the upper end of the jet pipe 2 from the outside air, the treatment liquid 3 in the fermenter 1 can maintain a state capable of anaerobic methane fermentation. In addition, in proportion to the length of the inner end protruding portion of the ejection pipe 2 inside the fermentation layer 1 main body, the liquid level difference H in the state immediately before ejection in FIG. As for the diameter of the pipe 2, the amount of one jet increases in proportion to the diameter, while the time interval during which the geyser phenomenon occurs increases. By using these things, various adjustments of the geyser phenomenon can be made.

The horizontal cross-sectional shape of the jet pipe 2 is most desirably circular. However, functionally, it is sufficient that a sufficient effect of surface tension is obtained around the inner end, and for example, an elliptical shape or a substantially square shape with rounded corners may be used. It is also possible to use a suitable horizontal cross-sectional shape.

FIG. 2 shows a second embodiment utilizing the above principle.
It is a sectional side view explaining one embodiment of a methane fermentation tank based on an indicated invention. This figure is characterized in that a separation tank 5 having a closed structure is mounted on the upper part of the methane fermentation tank 1 in comparison with the methane fermentation tank 1 in the basic configuration of the present invention shown in FIG. The outer end of the ejection pipe 2 is connected to the lower surface,
A gas collecting pipe 6 is connected relatively above the separation tank 5, and a processing liquid reflux pipe 7 is connected relatively below the separation tank 5, and the other end of the processing liquid reflux pipe 7 is connected relatively below the methane fermentation tank 1. Connected to the inside of the FIG. 2 shows a state after the above-mentioned geyser phenomenon has occurred several times after the methane fermentation tank 1 having the above configuration is filled with the treatment liquid 3.

As described above, due to the geyser phenomenon, a large amount of scum 4, treatment liquid 3, and generated gas 8 are integrally ejected from the inside of the methane fermentation tank 1 to the separation tank 5, and remain constant until the next geyser phenomenon occurs. It is left standing in the separation tank 5 during the time. In the meantime, the scum 4, the processing liquid 3, and the product gas 8, which are solid, liquid, and gaseous phases, are separated by their specific gravity differences. Specifically, the product gas 8 having the lightest specific gravity (mainly methane gas) Floats above the separation tank 5 and is sucked into the gas collection pipe 6, and the processing liquid 3 having the highest specific gravity precipitates below the separation tank 5 and is returned to the methane fermentation tank 1 through the processing liquid reflux pipe 7. Is done. As a result, only the scum 4 removed from the main body of the methane fermentation tank 1 by jetting in the separation tank 5 floats and accumulates (accumulates) on the liquid surface of the processing liquid 3 in the separation tank 5, and the separation is performed. The scum 4 can be removed from a take-out opening provided on the upper surface of the tank 5 and formed by an open / close lid (not shown).

Thus, the methane fermentation purification of the treatment liquid 3 is always performed in the methane fermentation tank 1,
Furthermore, continuous operation is possible by discharging the purified liquid through the inlet / outlet (not shown) and filling the new processing liquid 3 by the same amount. This can be achieved by a system that automatically controls the circulation of the processing liquid by operating, for example, an automatic opening / closing valve and a pump provided at the inlet / outlet (not shown) at regular intervals.

Further, the position at which the outer end of the jet pipe 2 is connected is not limited to the lower surface of the separation tank 5 as described above, but is directed toward the suction ports of the gas collection pipe 6 and the processing liquid recirculation pipe 7. It can be connected to any position unless it is directly ejected. For example, a connection configuration is also possible in which the jet pipe 2 is bent into an inverted J-shape and its outer end (downward end) penetrates from the ceiling wall of the separation tank 5 to the inside.

Next, FIG. 3 is a sectional side view for explaining one embodiment of the methane fermenter 1 according to the third and fourth aspects of the present invention. This figure is characterized in that the methane fermenter 1 according to claim 2 shown in FIG. 2 is characterized in that the methane also serves as the gas storage so that the periphery of the connection part of the jet pipe 2 is at the highest position. The point at which the ceiling of the fermenter 1 main body is inclined and the separation tank 5 containing the outer end of the ejection pipe 2 and receiving the ejected matter are provided with the gas collection pipe 6 through the scum / treatment liquid discharge port 9 and the scum stationary. The point is that the tank 10 has a double structure.

Specifically, in FIG. 3, the ceiling of the main body of the methane fermentation tank 1 is integrated with the gas storage section, and the periphery of the left side of the figure to which the jet pipe 2 is connected is the highest position. It slopes down to the right. A gas collection pipe 6 containing the outer end of the jet pipe 2 and having a scum / treatment liquid discharge port 9 opened downward at a relatively lower position is installed at an upper position of the methane fermentation tank 1. The scum / processing liquid outlet 9 is located at a lower portion of the gas collecting pipe 6 and the processing liquid reflux pipe is disposed at a relatively lower position along the slope of the ceiling of the main body of the methane fermenter 1. 7
A scum standing tank 10 connected to the methane fermentation tank 1 is also installed at the upper position of the methane fermentation tank 1. The treatment liquid reflux pipe 7 is located below the inclined portion of the main body of the methane fermenter 1 and is connected to a waste inlet 11 penetrating through the main body of the methane fermenter 1. FIG. 3 shows a state after the above-mentioned geyser phenomenon has occurred several times after the treatment liquid 3 has been charged into the methane fermentation tank 1 having the above configuration.

By providing the ceiling with the inclination as described above, the generated gas 8 is concentrated around the connection position of the jet pipe 2 serving as a gas storage part, and a gas layer is formed more quickly. As a result, the effect that the frequency of occurrence of the geyser phenomenon increases is produced.

Next, as the operation of the double-structure separation tank 5 according to the present embodiment, first, a large amount of scum 4, treatment liquid 3,
The generated gas 8 is integrally ejected and stored in the gas collection pipe 6, and the length and diameter of the ejection pipe 2 or the inclination of the ceiling of the main body of the methane fermentation tank 1 are adjusted in advance, thereby forming the separation tank 5.
The water level of the processing liquid 3 therein stabilizes at a position higher than the scum / processing liquid discharge port 9 as shown in the figure. Then, the product gas 8 containing a large amount of methane gas having a low specific gravity is floated and separated in the gas collection pipe 6. At this time, the water level of the processing liquid 3 is scum
Since the gas collecting pipe 6 is located above the discharge port 9, the gas collecting pipe 6 has an almost completely closed structure, and efficient gas collection without mixing of outside air is performed. In this configuration, it is also possible to employ a configuration in which a product gas suction means such as an air pump is provided at the upper end of the gas collection pipe 6 to actively collect the gas.

Next, the processing liquid 3 potentially containing the scum 4 is supplied through the scum / processing liquid discharge port 9 to the scum standing tank 10.
Is stored in Among them, the geyser phenomenon and generated gas 8
The scum 4 is allowed to stand still without being affected by the floating flow of the scum 4 and the scum 4 is properly formed and the scum layer 4 is appropriately formed, so that the scum 4 can be efficiently removed from the outlet (not shown).

At the same time, the processing liquid 3 which settles in the scum standing tank 10 is returned to the inside of the methane fermentation tank 1 via the processing liquid reflux pipe 7 and the waste inlet 11 which are installed obliquely downward. . Here, the waste inlet 11 protrudes deeper than the inner end between the jets so as not to be affected by the geyser phenomenon. With the above cycle,
It is possible to efficiently collect the generated gas 8 and remove the scum 4 while maintaining the airtightness inside the methane fermenter 1.

In the embodiment described above, the product gas 8 to be collected contains a large amount (about 77%) of highly flammable methane gas, so that the fuel gas used for heating the methane fermenter 1 is used. An efficient energy-saving process can be realized by reusing as.

Also, since there is no need to use metals,
By manufacturing the methane fermentation tank 1 as all-concrete, semi-permanent use without maintenance is possible.

According to the anaerobic methane fermentation purification treatment described above, the treatment liquid 3 is purified to a state where it can be reused as livestock washing water. In addition, since the methane fermentation tank 1 according to the present invention has a closed structure and is isolated from the outside air, there is an advantage that an odor is not generated outside even when methane fermentation purification treatment of organic waste is performed inside.

[0036]

As described above, according to the methane fermentation tank according to the present invention, the fecal matter which is a cause of scum generation, which has conventionally been a problem in the use of a methane fermentation tank (anaerobic methane fermentation purification treatment), is removed. The practical solution in terms of operating costs and the like can be realized in that the method can be used only for the treatment of only urine and washing water. In addition, as a result, labor for separating feces and urine is eliminated, and feces with a large amount of organic matter are processed together, so that a larger amount of methane gas that can be used as an energy source can be collected, and scum that can be used as compost can be collected. It becomes possible.

As a whole, the use of the methane fermentation tank according to the present invention makes it possible to more simply save cost, energy and resources in the anaerobic methane fermentation purification treatment of organic waste.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of a geyser phenomenon generated by the configuration of the first aspect of the present invention.

FIG. 2 is a side sectional view for explaining one embodiment of a methane fermentation tank based on the invention of claim 2;

FIG. 3 is a side sectional view for explaining one embodiment of a methane fermentation tank based on the inventions according to claims 3 and 4.

FIG. 4 is a diagram illustrating a basic process of an anaerobic methane fermentation purification process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Methane fermenter 2 Spout 3 Waste treatment liquid 4 Scum (scum layer) 5 Separation tank 6 Gas collection pipe 7 Treatment liquid recirculation pipe 8 Generated gas 9 Scum / treatment liquid outlet 10 Scum stationary tank 11 Waste inlet P Pressure of gas layer H Height of waste treatment liquid pushed up by gas pressure

Claims (4)

[Claims] 1. A methane fermentation tank having a closed structure, comprising: a gas storage portion for storing gas generated by methane fermentation in the upper portion; a gas storage portion projecting downward through a ceiling of the gas storage portion; A methane fermentation tank characterized by comprising: an ejection pipe whose cut end plane is located horizontally and the other end is disposed outside the methane fermentation tank. 2. A separation tank having a gas collection tube at an upper portion, a treatment liquid reflux tube communicating with the inside of the methane fermentation tank at a lower portion, and an outer end of the ejection tube connected to an arbitrary position to form a sealed structure. The methane fermentation tank according to claim 1, wherein 3. Includes an outer end of the ejection pipe to absorb a generated gas received and ejected from the ejected material,
A gas collection pipe having a scum / processing liquid discharge port for discharging the processing liquid and scum to the outside by its own weight, and a gas collection pipe including the lower part of the gas collection pipe where the scum / processing liquid discharge port is located. 2. A scum stationary tank having a reflux pipe for sucking and returning a processing liquid which is a residue and a processing liquid which precipitates downward after receiving scum into the methane fermentation tank. Methane fermentation tank. 4. The methane fermentation tank according to claim 1, wherein a slope is provided on a ceiling of the gas storage unit so that a periphery of a connection part of the ejection pipe is at a highest position.