JP7502166B2 - Apparatus for feeding material to be treated, fermentation treatment apparatus, and method for operating the fermentation treatment apparatus - Google Patents

Description

The present invention relates to a device for feeding organic waste, which is the material to be treated, into a vertical fermentation tank for anaerobic fermentation treatment, a fermentation treatment device, and a method for operating the fermentation treatment device.

Patent Document 1 discloses a fermentation treatment device that subjects organic waste containing solid matter, which is the material to be treated, to a fermentation tank without prior solubilization treatment and performs anaerobic fermentation treatment.

Organic waste containing solid matter includes organic solid waste such as food waste and paper waste, as well as biomass such as sewage sludge, human waste, livestock manure, agricultural residues, and food waste, or mixtures of these.

As shown in FIG. 9(a), the fermentation treatment device 10 described above is provided with a material input device 30 that inputs the material to be treated, that is, organic waste, into the fermentation tank 20. The material input device 30 is equipped with a cylindrical casing 31 and a pressing body 32 that presses the organic waste introduced into the cylindrical casing 31 toward the fermentation tank 20, and a configuration is disclosed in which the tip of the cylindrical casing is extended toward the tip side beyond the maximum advance position of the pressing body 32.

To prevent methane gas produced in the fermentation tank from leaking from the tip of the cylindrical casing, the organic waste pressed by the pressing body is configured to remain at the tip of the cylindrical casing 31 and provide a sealing function.

JP 2020-104072 A

However, in the treatment material introduction device provided in the above-mentioned fermentation treatment device, the organic waste remaining at the tip of the cylindrical casing is not compacted enough to provide a sufficient sealing function, and there is a risk that methane gas generated in the fermentation tank will leak from the cylindrical casing into the atmosphere, reducing the amount of gas that can be effectively used for power generation, etc.

In particular, as shown in FIG. 9(b), when the liquid level WL of the treatment liquid in the fermentation tank 20 falls below the tip of the cylindrical casing 31, methane gas is likely to leak through the gaps in the organic waste remaining at the tip of the cylindrical casing 31 (see FIG. 9(b)).

Conversely, as shown in FIG. 9(c), if the level of the treatment liquid in the fermentation tank rises significantly above the tip of the cylindrical casing 31, there is a risk that the treatment liquid will seep from the cylindrical casing 31 to the hopper 35 that is connected to the cylindrical casing 31 and supplies the organic waste. If the organic waste is immersed in the treatment liquid in the hopper 35, the organic waste cannot be properly sent to the fermentation tank 20.

One solution to this problem would be to equip the cylindrical casing with an electric valve to prevent leakage of the treatment liquid and methane gas. However, even if a knife gate valve, which is necessary to prevent organic waste from getting caught, is used as the electric valve, it is difficult to adequately prevent leakage of methane gas, and a separate gas sealing mechanism is required, resulting in problems such as increased equipment and maintenance costs.

In view of the above-mentioned problems, the object of the present invention is to provide a treatment material feeding device, a fermentation treatment device, and an operating method for the fermentation treatment device that can effectively prevent leakage of biogas produced in a fermentation tank with a simple configuration.

To achieve the above-mentioned object, the first characteristic configuration of the fermentation treatment device according to the present invention is a treatment material input device that inputs organic waste, which is the treatment material, into a vertical fermentation tank for anaerobic fermentation treatment, and is equipped with a cylindrical casing provided in the wall of the fermentation tank and a transport mechanism that transports the organic waste toward the opening of the cylindrical casing, and the cylindrical casing is provided with a consolidation promotion mechanism that consolidates the organic waste inside the cylindrical casing by the pressing force of the transport mechanism.

In order for the organic waste to be transported from the tip of the cylindrical casing into the inside of the fermentation tank, the organic waste must be pushed out of the tip of the cylindrical casing by the pressing force generated by the transport mechanism. The pressing force at that time compacts the organic waste to a certain extent, but the compaction promotion mechanism acts to further compact the waste inside the cylindrical casing. As a result, it is possible to prevent the biogas generated in the fermentation tank from leaking from the tip of the cylindrical casing into the inside of the cylindrical casing.

The second characteristic configuration is that, in addition to the first characteristic configuration described above, the compaction promotion mechanism is composed of a throttle mechanism in which the cross-sectional area of the cylindrical casing on the tip side of the conveying mechanism is smaller than the cross-sectional area of the cylindrical casing on the forward end side of the conveying mechanism.

The organic waste is effectively compacted at the tip of the cylindrical casing via a constriction mechanism that makes the cross-sectional area of the cylindrical casing at the tip smaller than the cross-sectional area of the cylindrical casing at the forward end of the conveying mechanism.

The third characteristic configuration is that, in addition to the second characteristic configuration described above, the throttle mechanism is configured with a wall surface whose cross-sectional area on the tip side gradually becomes smaller toward the tip than the cross-sectional area of the cylindrical casing on the forward end side of the conveying mechanism.

The wall of the cylindrical casing at the tip has a gradually smaller cross-sectional area toward the tip, forming a throttle mechanism. As the organic waste is pushed toward the tip, it gradually becomes compressed, effectively preventing the biogas generated in the fermentation tank from leaking out from the tip of the cylindrical casing.

The fourth characteristic configuration is that, in addition to the second or third characteristic configuration described above, the cross-sectional area ratio of the leading end side of the cylindrical casing to the cross-sectional area of the forward end side of the conveying mechanism is set in the range of 60 to 70%.

It is possible to effectively prevent the gas generated in the fermentation tank from leaking from the tip of the cylindrical casing while avoiding the tip becoming clogged with compacted organic waste. In other words, if the area ratio is greater than 70%, it is not possible to sufficiently prevent the leakage of biogas, and if it is less than 60%, there is a risk that the tip will become clogged.

The fifth characteristic configuration of the same is, in addition to the first characteristic configuration described above, that the compaction promotion mechanism is composed of a single or multiple protrusions formed on the inner wall surface of the tip portion of the cylindrical casing .

The protrusions formed on the inner wall surface at the tip function as constrictors to compact the organic waste.

The sixth characteristic feature of the present invention is that, in addition to the first characteristic feature described above, the compaction promotion mechanism is composed of a bent portion formed at the tip of the cylindrical casing.

The bend formed at the tip of the cylindrical casing suppresses the transmission of the pressing force of the conveying mechanism, and the organic waste is compacted between the forward end position of the conveying mechanism and the bend.

The seventh characteristic feature is that, in addition to any one of the first to sixth characteristic features described above, the opening edge at the tip of the cylindrical casing is formed so as to be perpendicular to the horizontal plane or so as to be inclined such that the lower opening edge protrudes further along the axial direction of the cylindrical casing than the upper opening edge.

As the biogas generated inside the fermentation tank rises through the treatment liquid, it flows into the cylindrical casing from the open end edge at the tip of the cylindrical casing, preventing leakage.

The fermentation treatment device according to the present invention is characterized in that it comprises a vertical fermentation tank for anaerobic fermentation treatment, a treatment material input device having any one of the first to seventh characteristic configurations described above, a gas leakage detection unit that detects leakage of biogas into the cylindrical casing, and a liquid level adjustment mechanism that adjusts the liquid level of the treatment liquid filled in the fermentation tank based on the state of biogas leakage detected by the gas leakage detection unit.

When the sealing function is exerted by the organic waste compacted inside the cylindrical casing by the compaction promotion mechanism, it is possible to prevent the biogas generated inside the fermentation tank from leaking into the cylindrical casing. However, if the sealing function of the organic waste compacted inside the cylindrical casing is impaired, the treatment liquid may flow back through the cylindrical casing and biogas may leak. In such a case, it becomes difficult to properly input the organic waste floating in the treatment liquid using the treatment object input device, but by adjusting the liquid level of the treatment liquid filled in the fermentation tank using the liquid level adjustment mechanism, the organic waste can be properly transported by the transport mechanism, and the sealing function can be restored again. Examples of gas leakage detection units include a gas sensor that detects biogas, a level sensor, and a monitor that can grasp the fluctuations in the amount of organic waste in the input hopper.

The characteristic configuration of the method for operating a fermentation treatment device according to the present invention is a method for operating a fermentation treatment device equipped with a vertical fermentation tank for anaerobic fermentation treatment and a treatment material input device having any one of the first to seventh characteristic configurations described above, in which the liquid level of the treatment liquid filled in the fermentation tank is adjusted based on the leakage state of the biogas leaking from the cylindrical casing.

If biogas leaks from the cylindrical casing, it can be determined that the consolidation by the consolidation promotion mechanism is insufficient, so by adjusting the liquid level of the treatment liquid filled in the fermentation tank, it is possible to enable appropriate consolidation treatment by the consolidation promotion mechanism.

As described above, the present invention makes it possible to provide a material feeding device, a fermentation treatment device, and an operating method for a fermentation treatment device that can prevent leakage of biogas produced in a fermentation tank.

FIG. 1 is an explanatory diagram of an organic waste treatment system incorporating a fermentation treatment device according to the present invention. FIG. 1 is an explanatory diagram of a fermentation treatment system incorporating a fermentation treatment device according to the present invention. FIG. 2A is an explanatory diagram of a fermentation treatment apparatus incorporating a treatment material feeding device according to the present invention, and FIG. 2B is an explanatory diagram of a consolidation promotion mechanism provided at the tip of a cylindrical casing. 1A is an explanatory diagram of a plan view of the treatment material input device, FIG. 1B is an explanatory diagram of a side view of the treatment material input device, FIG. 1C is an explanatory diagram of a cross section A of FIG. 1B, FIG. 1D is an explanatory diagram of a cross section B of FIG. 1B, FIG. 1E is an explanatory diagram of a cross section C of FIG. 1B, and FIG. 1F is an explanatory diagram of the positional relationship between an opening formed in a cylindrical casing and a pressing body. (a) is an explanatory diagram of a settling promotion blade, (b) is an explanatory diagram of a dispersion blade, and (c) is an explanatory diagram of a scraping blade. FIG. 1A is an enlarged explanatory diagram of a main part of the feeding mechanism in which the pressing body has retreated to the base end side, and FIG. 1B is an enlarged explanatory diagram of a main part of the feeding mechanism in which the pressing body has advanced to the forward end position and the organic waste has been compacted by the compaction promotion mechanism. 1A to 1E are explanatory diagrams of other embodiments of the consolidation promotion mechanism. 1A and 1B are explanatory diagrams of other embodiments of the consolidation promotion mechanism. FIG. 1 is an explanatory diagram of a fermentation treatment device according to the prior art; (a) is an explanatory diagram of a state in which the level of the treatment liquid is appropriate; (b) is an explanatory diagram of a state in which the level of the treatment liquid is low; and (c) is an explanatory diagram of a state in which the level of the treatment liquid is high. 1A and 1B are explanatory diagrams showing another embodiment of the treatment object input device according to the present invention.

The following describes the device for feeding material to be treated, the fermentation treatment device, and the method for operating the fermentation treatment device according to the present invention with reference to the drawings.

[Description of the system incorporating the fermentation treatment device]
The process carried out in an organic waste treatment system is shown in Figure 1. This system treats various organic wastes of different origins, such as municipal solid waste, human waste, septic tank sludge, and sewage sludge, and recovers the energy contained in the organic wastes as biogas (methane gas and carbon dioxide, mainly methane gas, so hereinafter also referred to as "methane gas").

Combustible waste such as paper waste, kitchen waste, and resin collected from ordinary households is crushed into small pieces using a crusher or other equipment, and a pre-processing step is carried out to separate organic solid waste suitable for fermentation treatment from resin, inorganic matter, metals, and other waste that is not suitable for fermentation treatment. The waste that is not suitable for fermentation is disposed of in a waste incineration facility, and the waste that is suitable for fermentation is fed into a fermentation treatment device and processed into methane fermentation.

In addition to combustible waste, which is suitable for fermentation, this fermentation treatment equipment can simultaneously treat human waste, septic tank sludge, sewage sludge, and excess sludge. The materials to be treated in the fermentation treatment equipment include organic solid waste such as food waste and paper waste, sewage sludge, human waste, and septic tank sludge, as well as biomass such as livestock manure, agricultural residues, and food waste, and organic waste consisting of these materials alone or mixed together.

The methane gas contained in the methane gas produced in the methane fermentation process is recovered as renewable energy, and the fermentation residue is incinerated after being subjected to residue treatment such as dehydration. The dehydrated liquid produced by the dehydration process of the fermentation residue is purified by biological treatment such as the activated sludge method, and the excess sludge produced by this biological treatment is suitable for fermentation and is subjected to methane fermentation.

[Description of the fermentation processing system]
2 shows a fermentation treatment system incorporating the fermentation treatment device 10. Household waste collected by a garbage collection truck 90 and carried to a household waste yard 91 is transported by a wheel loader 92 to a conveyor mechanism and fed into a bag breaker 93.

Household waste torn by the bag breaker 93 is fed into a sorter 94, where it is sorted into light materials unsuitable for fermentation 94a such as resin, heavy materials unsuitable for fermentation such as metal components 94b, and materials suitable for fermentation such as kitchen waste and paper waste 94c, and the materials suitable for fermentation 94c are accumulated in a suitable materials yard 95. The suitable materials for fermentation are further fed from the suitable materials yard 95 into a suitable materials hopper 96, which is crushed into small pieces by a crushing and sorting machine 97, and the suitable materials for fermentation that have been sorted by wind and sieve are stored in a stock case 80. A roll screen sorter or the like is used as the sorter 94.

The organic waste filled in the stock case 80 is fed into the hopper mechanism 35 of the fermentation treatment device 10 by the electric chain mechanism 81, and then fed into the fermentation tank 20 via the pushing mechanism 30 for methane fermentation treatment.

Biogas such as methane gas produced in the fermentation tank 20 is extracted from the gas exhaust section 50 and collected in the gas holder 84, where it is desulfurized in the desulfurization tower 86 and then used as fuel for the gas combustion device 88. Reference numeral 87 denotes fuel (LPG cylinder). Hot water heated by the gas combustion device 88 is supplied to the insulation jacket of the fermentation tank 20 as a heat source.

After anaerobic fermentation in the fermenter 20, the fermented liquid is subjected to solid-liquid separation (dehydration), and the liquid is stored in the fermented sludge storage tank 89 filled with activated sludge. The fermented liquid from the fermented sludge storage tank 89 is led to the mixing tank 98 where a flocculant is added, and then led to the sludge dehydrator 99 where the solid is separated into liquid and the solid is filled into the stock case 80 and sent to the incineration facility for incineration. The liquid is biologically treated in the biological treatment tank 79, the treated water is discharged, and the excess sludge is put into the fermenter 20 or treated outside the system.

[Description of the fermentation treatment device]
The overall configuration of the fermentation treatment device is shown in Fig. 3(a). The fermentation treatment device 10 is configured with a fermenter 20, an input mechanism 30, an agitation mechanism 40, a gas exhaust section 50, a treated liquid outlet 60, and a mechanism for discharging material unsuitable for fermentation 70, and is an apparatus for directly inputting a material suitable for fermentation, i.e., organic waste containing solid matter, which is a material to be treated, into the fermenter 20 and subjecting it to anaerobic fermentation treatment without solubilization treatment using a separate solubilization treatment tank or the like. The input mechanism 30 serves as the material to be treated input device of the present invention.

The fermentation tank 20 is a vertical treatment tank formed into a cylindrical shape using steel plates, and a jacket 22 that serves as a flow path for the heat medium is provided on the side wall, and the heat medium supplied from the heat medium supply section 23 passes through the jacket 22 and is discharged from the heat medium discharge section 21. Warm water is preferably used as the heat medium, and by supplying warm water of, for example, about 57°C to the jacket 22, the treatment liquid in the tank, i.e., the fermentation liquid, is heated to a temperature of about 55°C suitable for fermentation.

A disk-shaped lid 25 is removably fixed to the top of the fermentation tank 20 by a flange so that the inside of the tank is sealed. The lid 25 supports the stirring mechanism 40 and is connected to a pipe equipped with a methane gas exhaust valve V3 that functions as a gas exhaust section 50 for extracting methane gas produced by the anaerobic fermentation process, and is also provided with a viewing window 26 for visually checking the inside of the tank.

A funnel-shaped section 24 that gradually narrows downward is formed at the lower end of the side wall of the fermentation tank 20, and a mechanism 70 for discharging materials unsuitable for fermentation is provided at the center of the bottom.

The fermentation unsuitable material discharge mechanism 70 is a mechanism for discharging fermentation unsuitable materials such as sand, shells, and metals mixed in the fermentation liquid from the fermentation tank 20, and is composed of a cylindrical section 73 that protrudes downward from the bottom of the fermentation tank 20 and has a smaller diameter than the fermentation tank 20, and double damper mechanisms 71, 72 attached to the cylindrical section 73. With the lower damper 72 closed, the upper damper 71 is opened to take in the fermentation unsuitable materials, and then the upper damper 71 is closed and the lower damper 72 is opened to remove the fermentation unsuitable materials from the tank.

When sand, metal, shells, and other materials unsuitable for fermentation that are mixed in with the material to be treated gradually settle in the fermentation liquid and accumulate at the bottom, there is a risk that the effective fermentation volume will decrease and the fermentation efficiency will decline. However, by accumulating the materials unsuitable for fermentation in the cylindrical section 73 formed at the bottom and discharging them outside the tank via the double damper mechanism 71, 72, it is possible to avoid a decrease in the fermentation volume without requiring a large power source such as a pump device and while maintaining an anaerobic state.

[Explanation of the stirring mechanism incorporated in the fermentation treatment device]
The stirring mechanism 40 is provided to stir the organic waste put into the fermentation tank 20 inside the tank, and is configured with a stirring motor 45 installed on the top of the lid body 25, a vertically oriented rotating shaft rotatably supported by bearings on the lid body 25, a stirring shaft 41 connected to the rotating shaft via a coupling 43, and stirring blades 42, 44, 46 fixed to the stirring shaft 41. The stirring shaft 41 is installed so as to coincide with the axis of the fermentation tank 20.

The upper end of the agitator shaft 41 is connected to a rotating shaft supported by the lid 25 via a coupling 43, and the lower end of the agitator shaft 41 is a free end that is not supported by a shaft. Therefore, when maintenance is required, the agitator shaft 41 can be pulled out from the upper end of the fermenter 20 together with the agitator blades 42, 44, and 46 by removing the lid 25 from the fermenter 20 without disassembly or removing the sludge from the tank.

As shown in Figures 3 and 5(a), the sedimentation promotion blade 42 located at the top is composed of two flat blade pieces 42a fixed to a sleeve 42b fitted and fixed to the agitator shaft 41 so that the blade pieces 42a form a central angle of 180°. The blades are positioned so that they cross the liquid level of the treatment liquid in the fermentation tank 20, preferably so that the liquid level is located in the vertical center of the blade surfaces, and the tips of the blades extend to a position near the inner wall surface of the fermentation tank 20.

The upper edge 42U of each blade surface is fixed to the sleeve 42b so that it is inclined from the lower edge 42L toward the rotation direction of the agitator shaft 41. Therefore, when the agitator shaft 41 rotates, the settling promotion blades 42 push down the unfermented organic solid waste floating on the surface of the fermentation liquid so that it efficiently settles below the liquid surface, promoting the fermentation process in the liquid. Note that in Figure 5(a), the upper drawing is a plan view and the lower drawing is a front view.

In this embodiment, the radial length of each blade 42a is set to be slightly shorter than the inner diameter of the fermenter 20, and the upper end is set to be inclined in the direction of rotation at an angle of 15 to 60 degrees, preferably 30 to 45 degrees, relative to the horizontal plane.

As shown in Figures 3(a) and 5(b), three stages of dispersion blades 44 are provided below the settling promotion blades 42 in the vertical direction. In Figure 5(b), the upper drawing is a plan view, and the lower drawing is a front view.

The dispersion blades 44 are composed of two flat blade pieces 44a fixed to a sleeve 44b fixed to the agitator shaft 41 at a central angle of 180°. The radial length of each blade piece 44a is shorter than that of the settling promotion blades 42, and is set to a length in the range of 40-90%, preferably 50-70%, of the inner diameter of the fermentation tank 20.

The stirring action of the dispersion blades 44 releases methane gas trapped in the material during the fermentation process from the material, suppressing the rise in liquid level caused by volume expansion due to methane gas, and dispersing the material in the fermentation liquid further promotes fermentation. In addition, stirring the fermentation liquid makes the temperature distribution of the fermentation liquid, which is transferred heat from the heat medium supplied to the jacket 22, uniform, and the entire fermentation liquid is maintained at a good fermentation temperature.

In addition, one of the three vertically arranged dispersion blades 44 is configured to be located at a height near the position where the organic waste is charged by the charging mechanism 30, so that the organic waste immediately after being charged into the fermentation tank 20 by the charging mechanism 30 is quickly dispersed in the fermentation liquid.

As shown in Figures 3 and 5(c), the scraping blade 46 is provided below the dispersion blade 44. In Figure 5(c), the upper drawing is a plan view, and the lower drawing is a front view.

The scraping blade 46 is fixed to the agitator shaft 41 at the bottom of the fermenter 20 and includes a lower dispersion blade piece 46a that disperses the material to be treated in the fermentation liquid, and a scraping blade piece 46c that is fixed to the tip of the lower dispersion blade piece 46a and scrapes the material unsuitable for fermentation that has settled in the fermentation liquid to the unsuitable for fermentation discharge mechanism 70.

Specifically, the scraping blade 46 is composed of two lower dispersion blade pieces 46a with a U-shaped cross section, which are fixed to a sleeve 46b that is fitted and fixed to the agitator shaft 41 so that the central angle is 180°, and a scraping blade piece 46c with a U-shaped cross section provided at the tip side of the lower dispersion blade piece 46a. The scraping blade piece 46c is arranged in an inclined position so as to face the funnel-shaped portion 24 of the side wall of the fermentation tank 20, and the lower dispersion blade piece 46a is arranged in a horizontal position so that one end is fixed to the sleeve 46b and the other end is fixed to the blade piece 46c.

The openings of the blades 46a, 46c, which are formed with a U-shaped cross section, are arranged to face the direction of rotation, and the U-shaped recesses capture the unsuitable for fermentation that has settled to the bottom of the fermenter 20 and scrape it up toward the cylindrical section 73. In the process, the suitable materials for fermentation that are mixed in with the unsuitable materials for fermentation are stirred, promoting the fermentation process.

In other words, to prevent the unsuitable for fermentation that has settled inside the fermenter 20 from accumulating at the bottom and to prevent the unsuitable for fermentation from causing bridging, the unsuitable for fermentation is efficiently scraped up by the scraping blade 46c to the unsuitable for fermentation discharge mechanism 70. In the process, the material to be treated that is mixed in with the unsuitable for fermentation is stirred by the lower dispersion blade 46a, promoting the fermentation process.

[Description of the device for feeding material to be treated incorporated in the fermentation treatment device]
As shown in Fig. 3(a) and Fig. 4(a) to (e), the treatment material input device is configured to include a hopper mechanism 35 and a push-in input mechanism 30 that transports the organic waste input into the hopper mechanism 35 to the fermenter 20. The push-in input mechanism 30 is configured to include a cylindrical casing 31 (see Fig. 4(e)) with a diamond-shaped cross section when viewed in the axial direction, which is inserted into and flange-fixed to a flange pipe 36 formed on the wall of the fermenter 20 in an inclined position at a predetermined inclination angle θ with respect to the horizontal plane so that the tip side faces downward, a pressing body 32 with a rectangular cross section that is housed in the cylindrical casing 31, and a hydraulic drive mechanism 33 that drives the pressing body 32 to move forward and backward along the axis of the cylindrical casing 31. The push-in input mechanism 30 functions as a transport mechanism of the present invention.

The cylindrical tip FE of the cylindrical casing 31 is inserted and fixed into a flange pipe 36 attached to the side wall of the fermentation tank 20 so that it is immersed in the fermentation liquid inside the fermentation tank 20. In this embodiment, the flange pipe 36 is set at an inclination of about 30° with respect to the horizontal plane, and the inclination of the cylindrical casing 31 is also set at an inclination of about 30° with respect to the horizontal plane. Note that although the inclination is set at about 30° in this embodiment, it can be set appropriately within the range of 15 to 45°.

A hopper mechanism 35 that supplies organic waste from the tip of the cylindrical casing 31 to the push-in feeding mechanism 30 is provided at the top of the push-in feeding mechanism 30. The hopper mechanism 35 has a rectangular cylindrical storage section formed by four side walls 35a that hang down from an upper opening 35d, which is an input section equipped with a lid 35c that can be opened and closed. The side walls 35a are connected to a pair of opposing walls that are arranged to sandwich the axis of the cylindrical casing 31 in a plan view, and an inclined wall section 35b is formed that gradually narrows toward the bottom end.

For ease of explanation, the lid 35c is shown in broken lines in FIG. 4(a). One end of the lid 35 is attached to the side wall 35a via a hinge mechanism h so that it can be opened and closed freely. Also, reference numeral 35h in FIG. 4(c) denotes an inspection window.

The material suitable for fermentation is introduced into the storage section from the upper opening 35d, and is dropped into the cylindrical casing 31 through the opening 31a formed in the cylindrical casing 31 of the push-in introduction mechanism 30 from the lower end opening of the inclined wall section 35b.

In other words, an opening 31a is formed in the upper part of the cylindrical casing 31 that constitutes part of the feeding mechanism 30, and the longitudinal direction of the opening 31a is shaped to follow the axis of the cylindrical casing 31. The lower ends 35u (see FIG. 4(a)) of the inclined wall portion 35b are arranged so as to be connected to the longitudinal edges of the opening 31a without any steps.

The pressing surface 32a of the pressing body 32 is configured in a rectangular shape that extends above an imaginary plane P that passes through the longitudinal edges of the opening 31a and the connecting parts P1, P2 of the lower ends of the inclined wall parts 35b, and the inclination angle of the inclined wall parts 35b that connect to the cylindrical casing 31 is set to an inclination angle in the range of 10 to 60 degrees, preferably 30 to 50 degrees, with respect to the horizontal direction (see FIG. 4(f)).

By adopting such a configuration, even if the organic waste fed into the hopper mechanism 35 is compressed near the lower end of the inclined wall portion 35b, which may cause a bridge to form, the compressed portion is scraped off by the pressing surface 32a, which causes the weight balance of the organic waste near the lower end of the inclined wall portion 35b to be disrupted and the formation of a bridge is prevented. Even if a bridge forms near the lower end of the inclined wall portion 35b of the hopper mechanism 35, the compressed portion is scraped off by the pressing surface 32a, destroying the bridge.

In addition, whether the material to be treated is organic solid waste such as food waste or paper waste, highly fluid sewage sludge, human waste, livestock manure, agricultural residues, food waste, or a mixture of these, the cylindrical casing 31 with the pressing body 32 built in is attached in an inclined position to the side wall of the fermentation tank 20, so that the material can be stably pushed into the fermentation tank 20 by the pressing body 32, which is driven back and forth by the drive mechanism 33.

As shown in FIG. 4(b), the attachment position of the hopper mechanism 35 to the cylindrical casing 31 is set so that the liquid level of the fermentation liquid in the fermenter 20 is near the connection position CA of the hopper mechanism 35 to the wall of the cylindrical casing 31. With this setting, the fermentation liquid that flows into the cylindrical casing 31 does not leak out from the hopper mechanism 35, and the organic waste supplied from the hopper mechanism 35 is given an appropriate amount of moisture, so that it disperses quickly in the fermentation liquid after being forced into the fermenter 20.

The hopper mechanism 35 is configured with a funnel-shaped portion consisting of a rectangular cylindrical storage section 35a with side walls hanging down from a rectangular upper opening, and an inclined wall section 35b at the bottom end of the storage section 35a that tapers toward the cylindrical casing 31. In addition to the fermentation-suitable materials selected from combustible waste, which is organic solid waste, that are fed into the storage section 35a, human waste, septic tank sludge, and even sewage sludge are also fed in, and while they are piled up inside and mixed, they are fed into the fermentation tank 20 by the pushing-in feeding mechanism 30.

The wall portion 35a of the hopper mechanism 35 connected to the cylindrical casing 31 is formed with a front wall portion 35e on the side of the advancing direction of the pressing body 32 inclined toward the advancing direction of the pressing body 32 at the connection portion with the cylindrical casing 31 (see Figures 4(b) and (d)).

When the organic waste is pressed inside the cylindrical casing 31 by the pressing body 32, a consolidation stress acts on the front wall 35e and the pressing body 32 when it is consolidated between the front wall 35e connected to the cylindrical casing 31. At this time, if the front wall 35e on the advancing side of the pressing body 32 is formed in an inclined position toward the advancing direction of the pressing body 32 at the connection part with the cylindrical casing 31, part of the organic waste near the top of the pressing body 32 escapes into the space formed by the inclined front wall 35e, so a sudden consolidation action is avoided and the waste is smoothly pressed and supplied.

The rear wall 35f of the wall 35a of the hopper mechanism 35 connected to the cylindrical casing 31 on the backward direction side of the pressing body 32 is located on the backward direction side of the pressing body 32 from the opening 31a.

When the pressing body 32 is driven to the maximum advanced position, the length of the pressing body 32 must be longer than the longitudinal length of the opening 31a so that organic waste does not fall rearward from the rear end wall of the pressing body 32 from the opening 31a, which causes the inconvenience of increased parts costs. Therefore, if the longitudinal length of the opening 31a is limited, the capacity of the hopper mechanism 35 must be limited accordingly. Even in such a case, if the wall portion 35a of the hopper mechanism 35 connected to the cylindrical casing 31 is configured so that the rear wall portion 35f on the retreating side of the pressing body 32 is positioned further backward than the opening 31a, it becomes possible to ensure the capacity of the hopper mechanism 35 while limiting the length of the pressing body 32 and reducing parts costs.

As shown in Figures 3(a) and (b), the cylindrical casing 31 has a tip portion FE that extends further toward the tip side than the forward end position of the pressing body 32 of the forcing mechanism 30, and is provided with a consolidation promotion mechanism 31b that consolidates the organic waste at the tip portion FE by the pressing force of the forcing mechanism 30. The consolidation promotion mechanism 31b is composed of a throttle mechanism that makes the cross-sectional area of the cylindrical casing 31 on the tip side smaller than the cross-sectional area on the forward end side of the pressing body 32.

The throttle mechanism is composed of a wall surface in which the cross-sectional area at the tip side becomes gradually smaller toward the tip than the cross-sectional area of the cylindrical casing 31 at the forward end side of the pressing body 32, so that the organic waste is gradually compressed as it is pushed toward the tip side, thereby preventing the occurrence of a situation in which the tip portion FE becomes blocked by the compressed organic waste.

When the area ratio of the cross-sectional area of the cylindrical casing 31 at the forward end side of the pressing body 32 to the cross-sectional area of the tip side is set in the range of 60 to 70%, it is possible to effectively suppress leakage of gas generated in the fermentation tank from the tip of the cylindrical casing while avoiding the tip from being blocked by compacted organic waste. If the area ratio is greater than 70%, gas leakage cannot be sufficiently suppressed, and if it is less than 60%, there is a risk of the tip being blocked.

In the example shown in FIG. 3(b), the four wall surfaces are configured to slope equally toward the axis so that the cross-sectional area gradually decreases along the axial direction of the cylindrical casing 31.

Figures 6(a) and (b) show the state in which the pressing body 32 is driven backward along the cylindrical casing 31 to near the rear end and the state in which it is driven forward to the front end. The rear end position of the pressing body 32 driven backward is set so that it is located inside the cylindrical casing on the rear end wall 35f side of the hopper mechanism 35 of the opening 31a of the cylindrical casing 31, so that the tip of the pressing body 32 can be slightly seen through the opening 31a.

The pressing surface 32a of the pressing body 32 is formed on a plane perpendicular to the advancing direction, so that the maximum pressing force acts on the organic waste. Then, when the pressing body 32 is driven backward after reaching the maximum advancing position inside the cylindrical casing 31, new organic waste is dropped and supplied from the hopper 35 into the hollow space formed inside the cylindrical casing 31.

The pressing surface 32a of the pressing body 32 is formed on a surface perpendicular to the advancing direction, and is formed in a stepped shape that protrudes in stages from the top to the bottom when viewed from the side. Even when maximum pressing force is applied to the organic waste, the organic waste pressed by the pressing surface on the lower side of the cylindrical casing 31 is pressed further to the tip side F of the cylindrical casing 31 than the organic waste pressed by the pressing surface on the upper side of the cylindrical casing 31.

By adopting this configuration, the volume of the cavity formed in the cylindrical casing 31 when the pressing body 32 is driven backward becomes larger than when pressed by a flat pressing surface, and a larger amount of organic waste can be dropped and supplied into the cylindrical casing 31.

The inclination angle of the stepped shape formed on the pressing surface 32a (the inclination angle α of the tip envelope surface of the step portion relative to the axis of the cylindrical casing 31) is preferably set to an angle equal to or greater than the inclination angle θ of the cylindrical casing 31 relative to a plane perpendicular to the axis of the cylindrical casing 31. Since previously pressed organic waste will no longer be present on the falling trajectory of the organic waste falling vertically from the hopper mechanism 35 into the cylindrical casing 31, a larger amount of organic waste will fall and be supplied.

As shown in FIG. 6(a), with the pressing body 32 retracted inside the cylindrical casing 31, organic waste is supplied from the hopper mechanism 35 to the cylindrical casing 31. As shown in FIG. 6(b), when the pressing body 32 is then driven forward and pressed to the forward end position, the organic waste is compacted by the throttle mechanism constituting the compaction promotion mechanism 31b. As a result, leakage of gas generated in the fermentation tank 20 from the tip of the cylindrical casing 31 is effectively suppressed.

In other words, the treatment material input device comprises a cylindrical casing 31 provided on the wall of the fermentation tank 20, and a transport mechanism 30 that transports organic waste toward the opening of the cylindrical casing 31. The cylindrical casing 31 is provided with a consolidation promotion mechanism 31b that consolidates the organic waste inside the cylindrical casing 31 by the pressing force of the transport mechanism 30.

Furthermore, it is provided with a cord-like body 35g, one end of which is fixed to or near the connection between the cylindrical casing 31 and the wall portion 35e on the advancing side of the hopper mechanism 35, and the other end of which is hung along the opening to the input portion 35d of the hopper mechanism 35.

Even if a bridge occurs at the inclined wall portion 35b of the hopper mechanism 35, the bridge can be easily broken down by pulling the cord-like body 35g suspended over the input portion 35d. The cord-like body 35g can be made of a wire or chain. In addition, since a space is formed by the inclined portion of the front wall portion 35e at the connection portion where one end of the cord-like body 35g is fixed, there is no interference with the pressing body 32 even when the pressing body 32 is driven to the maximum advanced position. The pressing body 32 and the cord-like body 35g can be linked to automate the pulling of the cord-like body 35g.

A stroke gauge 32g is provided whose tip is fixed to the rear end 32e of the pressing body 32 and whose rear end protrudes from the rear end of the cylindrical casing 31. Because it is a hydraulic drive mechanism 33, if organic waste becomes clogged inside the cylindrical casing 31, the piston rod that drives the pressing body 32 may not operate even if maximum pressurized oil is being supplied to the oil passage.

In such a case, it is difficult to check from outside the cylindrical casing 31 whether the pressing body 32 has reached its maximum advanced position, but if a stroke gauge 32g is provided, the position of the pressing body 31 inside the cylindrical casing 31 can be easily checked from outside the cylindrical casing 31.

If the forcing mechanism 30 is in a vertical position, the liquid with high fluidity is fed into the tank before the solids, and if the forcing mechanism 30 is in a horizontal position, the liquid with high fluidity is not transported smoothly, and in either case, the composition of the material in the tank becomes unstable. However, if the forcing mechanism 30 is installed in an inclined position, this situation can be avoided.

[Other Aspects of the Throttle Mechanism]
7(a) to (e) show other examples of the throttle mechanism as the consolidation promotion mechanism 31b provided at the tip portion FE of the cylindrical casing 31. In FIG.

In this example, the cylindrical casing 31 disposed at the lower end of the hopper mechanism 35 has a cross section that is rectangular or square rather than rhombic when viewed in the axial direction. In FIG. 7(a), a pair of opposing wall surfaces (upper and lower wall surfaces and left and right wall surfaces) are both configured to incline toward the axial center of the cylindrical casing 31, but as shown in FIG. 7(b), only the pair of opposing wall surfaces may be configured to incline toward the axial center, or as shown in FIG. 7(c), only the pair of opposing wall surfaces may be configured to incline toward the axial center. Furthermore, as shown in FIG. 7(d), only one of the pair of opposing wall surfaces (the upper wall surface in this example) may be configured to incline toward the axial center.

Figure 7 (e) shows yet another embodiment of the compaction promotion mechanism 31b. In this example, a bent portion is formed at the tip of the cylindrical casing 31. The bent portion suppresses the transmission of the pressing force of the pressing body 32, and the organic waste is compacted between the forward end position of the pressing body 32 and the bent portion.

FIG. 10( a ) shows another embodiment of the push-in mechanism 30 .
The push-in feeding mechanism 30 includes a cylindrical casing 31 with a rectangular cross section that is disposed at an inclination angle θ with respect to the horizontal plane at the bottom of a hopper mechanism 35 that is substantially rectangular in shape. The horizontal width of the cylindrical casing 31 is formed to be the same as the horizontal width of the hopper mechanism 35, and the vertical width is formed to be approximately half of the horizontal width.

The cylindrical casing 31 is composed of a first cylindrical casing 31A to which a hopper mechanism 35 is connected, with the maximum advance position of the pressing body 32 as a boundary, and a second cylindrical casing 31B that can be flange-connected at the tip of the first cylindrical casing 31A, and is flange-connected to a flange pipe 36 formed on the wall of the fermentation tank 20 using bolts and nuts. Therefore, even if organic waste clogs the second cylindrical casing 31B, maintenance work can be easily performed by separating the flange connection part. In addition, in the figure, the first cylindrical casing 31A and the second cylindrical casing 31B are shown in a separated state for ease of understanding. Furthermore, although the maximum advance position of the pressing body 32 is located at the first cylindrical casing 31A, it may be located just before the first cylindrical casing 31A.

The tip of the second cylindrical casing 31B is provided with a compaction promotion mechanism 31b as shown in FIG. 7(b). Needless to say, the tip of the second cylindrical casing 31B may be provided with any of the compaction promotion mechanisms 31b as shown in FIG. 7(a) to (e). The cylindrical casing 31 is formed so that the open end edge at the tip is perpendicular to the horizontal plane. This configuration prevents the biogas generated inside the fermenter 20 from flowing into the cylindrical casing 31 from the open end edge at the tip of the cylindrical casing 31 as it rises through the treatment liquid.

As shown in FIG. 10(b), the cylindrical casing 31 may be formed so that the lower opening edge is inclined in the axial direction of the cylindrical casing 31 beyond the upper opening edge. If the lower opening edge is inclined in the axial direction of the cylindrical casing 31 beyond the upper opening edge, the opening edge is inclined at an acute angle (90°-α) from a position perpendicular to the horizontal plane, so that the occurrence of an undesirable situation in which the biogas generated inside the fermentation tank 20 flows into the cylindrical casing 31 from the opening edge at the tip of the cylindrical casing 31 as it rises through the treatment liquid can be more reliably prevented.

Even in the case of the cylindrical casing 31 shown in FIG. 3, it is preferable that the opening edge at the tip of the cylindrical casing is formed in a perpendicular position to the horizontal plane or in an inclined position in which the lower opening edge protrudes in the axial direction of the cylindrical casing beyond the upper opening edge, as shown in FIGS. 10(a) and (b).

8(a) and (b) show another embodiment of the compaction promotion mechanism 31b. In this example, three kamaboko-shaped protrusions 31P are arranged side by side toward the opening on the inner surface of the tip FE of the four walls of the cylindrical casing 31 formed parallel to the axis. When the organic waste is pressed by the pressing part 32, the organic waste is compacted in a path narrowed by the protrusions 31P. The number and shape of the protrusions, and the wall surface to which the protrusions are attached, are not particularly limited. For example, multiple protrusions that gradually increase in height toward the opening of the tip FE may be provided. Also, multiple protrusions that are linearly inclined toward the opening may be provided instead of the kamaboko-shaped protrusions 31P. Note that in FIG. 8(b), the wall surface on the front side of the page of the four walls of the cylindrical casing 31 is omitted.

[Explanation of the liquid level adjustment mechanism of the fermenter]
Since it is difficult to completely remove the materials unsuitable for fermentation from the organic waste, heavy materials among the materials unsuitable for fermentation that are put into the fermentation tank 20 together with the organic waste will sink to the bottom, while light materials such as resin pieces will become entangled with the viscous fermentation liquid and turn into lumpy scum that will float and accumulate on the surface of the fermentation liquid.

Therefore, the materials unsuitable for fermentation that have settled to the bottom are discharged to the outside via the unsuitable for fermentation discharge mechanism 70, and the scum that has floated and accumulated on the liquid surface is discharged together with the excess fermentation liquid by the liquid level adjustment mechanism 100.

As shown in FIG. 3(a), the liquid level adjustment mechanism 100 is configured with a drain pipe DT connected to the peripheral wall of the fermenter 20, a valve mechanism V1 provided in the drain pipe DT, a drain tank DM, etc.

The drain pipe DT is composed of a tube with a rectangular cross section, and is composed of a first pipe DT1 in a horizontal position whose end is connected to a position near the surface of the fermentation liquid in a height region of the peripheral wall of the fermenter 20 that overlaps with the height at which the stirring blades 42 are installed, and a second pipe DT2 whose position is changed vertically from the first pipe DT1, and the lower end of the second pipe DT2 is connected to the drain tank DM. The second pipe DT2 may be directly connected to the peripheral wall of the fermenter 20 without the first pipe DT1.

To allow unsuitable materials for fermentation to overflow from the drain pipe DT together with excess fermentation liquid, the end of the pipe is attached in a position where the upper and lower pipe walls sandwich the target liquid level set in the fermenter. In addition, the valve mechanism V1 is attached to the middle part of the second piping, and a knife gate valve is used to seal the liquid so that the biogas generated in the fermenter 20 does not leak.

The excess fermented liquid and scum SC that flow into the drain pipe DT when the valve mechanism V1 is closed is then temporarily opened to flow from the drain pipe DT into the drain tank DM and stored there. The valve mechanism V1 is repeatedly opened and closed at regular intervals to store the excess fermented liquid and scum SC in the drain tank DM, and then the valve mechanism V1 is closed and the drain valve DV is opened to discharge the excess fermented liquid and scum SC that have accumulated in the drain tank DM, and then the liquid is dehydrated.

In addition, when the level of the treated liquid in the fermenter 20 drops, a supply pipe DT3 is connected to the first pipe DT1 to supply the treated liquid or water stored in the drain tank DM to restore the liquid level.

Inside the hopper 35, there are provided a gas sensor Sg and a liquid level sensor Sl that function as gas leakage detectors. The gas sensor Sg detects the concentration of biogas leaked from the cylindrical casing 31, and the liquid level sensor Sl indirectly detects gas leakage by monitoring the liquid level inside the hopper 35. A control unit (not shown) is provided that adjusts the liquid level adjustment mechanism 100 based on the values of the gas sensor Sg and the liquid level sensor Sl. The liquid level sensor Sl may also be installed in the fermenter 20.

The control unit is configured to adjust the liquid level of the treatment liquid filled in the fermentation tank based on gas leakage information such as the gas concentration of methane gas detected by the gas leakage detection unit and the liquid level detected by the liquid level sensor Sl. Specifically, if the liquid level is in a normal range that is lower than the level of the communication position CA to the wall of the cylindrical casing 31 and higher than the level that ensures the liquid seal at the tip of the cylindrical casing 31, the sealing mechanism can be restored by consolidating again using the consolidation promotion mechanism 31b. If the gas concentration rises above a preset threshold, it is determined that the sealing mechanism has broken down and methane gas has leaked from the cylindrical casing 31, and if the liquid level has risen above the normal range, the liquid level is lowered to the communication position CA of the hopper mechanism 35 to the wall of the cylindrical casing 31 to ensure the liquid seal at the tip of the cylindrical casing 31, and the sealing mechanism is restored using the consolidation promotion mechanism 31b. If the liquid level has dropped below the normal range, the sealing mechanism can be restored again using the consolidation promotion mechanism 31b in that state. If the liquid level has dropped below the normal range, it is preferable to open the valve mechanism V3, introduce treatment liquid or water through the liquid supply pipe DT3, ensure a liquid seal at the tip of the cylindrical casing 31, and then consolidate using the consolidation promotion mechanism 31b to restore the sealing mechanism.

The gas sensor Sg constituting the gas leak detection unit may be a methane gas concentration sensor, a carbon dioxide gas concentration sensor, or an odor sensor capable of detecting odors generated along with biogas. The liquid level sensor Sl may be a sensor capable of measuring the liquid level position, such as a light, ultrasonic, or electromagnetic sensor. In addition, instead of the liquid level sensor Sl that monitors the liquid level in the hopper 35, a monitor device that monitors the liquid level or a monitor through a sight glass provided in the hopper 35 may be used to monitor the liquid level, and the control unit may be activated if an abnormal rise in the liquid level is confirmed.

In the above embodiment, an example was described in which the conveying mechanism was configured as a hydraulically driven push-in mechanism, but the mechanism for driving the pressing unit is not limited to hydraulic drive and may use an electric motor or air pressure. Also, other conveying mechanisms such as a screw conveying mechanism may be used instead of the pressing unit.

The above-described embodiment is one aspect of the present invention, and the present invention is not limited to this description. It goes without saying that the specific structure, size, material, etc. of each part can be appropriately modified and designed within the scope of the effect of the present invention.

10: Fermentation treatment device 20: Fermenter 30: Material to be treated input device (input mechanism)
31: Cylindrical casing 31b: Consolidation promotion mechanism 32: Pressing body 36: Flange pipe 37: Flange pipe 40: Stirring mechanism 41: Stirring shaft 42: Settling promotion blade 44: Dispersing blade 36: Scraping blade 50: Gas exhaust section 60: Treated liquid exhaust port 70: Fermentation unsuitable material discharge mechanism 71: Double damper mechanism 72: Double damper mechanism 73: Cylindrical section 100: Liquid level adjustment mechanism FE: Tip section

Claims (9)

An apparatus for feeding organic waste to a vertical fermentation tank for anaerobic fermentation,
A cylindrical casing provided on the wall of the fermenter;
a conveying mechanism for conveying organic waste toward the opening of the cylindrical casing;
Equipped with
The cylindrical casing is provided with a consolidation promotion mechanism for consolidating the organic waste inside the cylindrical casing by the pressing force of the transport mechanism. The processing material input device according to claim 1, wherein the compaction promotion mechanism is composed of a throttle mechanism that reduces the cross-sectional area of the cylindrical casing at the tip end of the conveying mechanism compared to the cross-sectional area at the forward end of the conveying mechanism. The processing material input device according to claim 2, wherein the throttle mechanism is configured with a wall surface whose cross-sectional area at the tip side is gradually smaller toward the tip than the cross-sectional area of the cylindrical casing at the forward end side of the conveying mechanism. The processing material input device according to claim 2 or 3, in which the cross-sectional area ratio of the leading end side of the cylindrical casing to the cross-sectional area of the forward end side of the conveying mechanism is set in the range of 60 to 70%. 2. The treatment object feeding device according to claim 1, wherein the consolidation promoting mechanism is constituted by one or more projections formed on the inner wall surface of the tip end of the cylindrical casing . The material feed device according to claim 1, wherein the compaction promotion mechanism is composed of a bent portion formed at the tip of the cylindrical casing. The processing material input device according to any one of claims 1 to 6, wherein the opening edge of the tip of the cylindrical casing is formed in a perpendicular position to the horizontal plane or in an inclined position in which the lower opening edge protrudes from the upper opening edge along the axial direction of the cylindrical casing. A vertical fermentation tank for anaerobic fermentation treatment;
A processing object input device according to any one of claims 1 to 7,
a gas leakage detection unit that detects leakage of biogas into the cylindrical casing;
a liquid level adjustment mechanism that adjusts the liquid level of the treatment liquid filled in the fermentation tank based on the biogas leakage state detected by the gas leakage detection unit;
The fermentation treatment device is provided with: A vertical fermentation tank for anaerobic fermentation treatment;
A processing object input device according to any one of claims 1 to 7,
A method for operating a fermentation treatment apparatus comprising:
A method for operating a fermentation treatment device, comprising adjusting the liquid level of the treatment liquid filled in the fermentation tank based on the leakage state of biogas leaking from the cylindrical casing.

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