JP2024059619A - Fermentation apparatus, method for using the fermentation apparatus, and method for producing methane gas - Google Patents

Abstract

[Problem] The problem is to propose a fermentation apparatus capable of suppressing the consumption of clean water such as clean water. [Solution] The fermentation apparatus 1 has a crushing process section 10 for crushing fermentation raw materials, and a fermentation tank 2, and the fermentation raw materials crushed in the crushing process section 10 are introduced into the fermentation tank 2, and the fermentation raw materials are fermented in the fermentation tank 2. The fermentation apparatus 1 has a reflux conveying path 60 for returning the water in the fermentation tank 2 to the crushing process section 10. [Selected drawing] Fig. 1

Description

The present invention relates to a fermentation apparatus and a method for producing methane gas using food waste as a fermentation raw material.

As one of the measures for effectively utilizing food waste, it has been proposed to generate methane gas by anaerobic digestion (methane gas fermentation) and collect and utilize the methane gas.
That is, food waste and the like are used as raw materials and fermented by anaerobic bacteria to generate methane gas, which can be used for power generation, etc.
Food waste is crushed into small pieces before being fed into the fermentation tank. A wet crushing device is often used to crush food waste.

JP 2018-26301 A

A wet crushing device is a device that crushes objects in liquid, and can crush objects more finely than a dry crushing device.
In the conventional technology, clean water such as tap water or groundwater is poured into a wet crushing device along with food waste, and with the chamber of the wet crushing device filled with water, the rotating blades are driven to crush the food waste.

As described above, the conventional fermentation apparatus injects clean water or the like into the wet crushing apparatus, which causes a problem of high consumption of clean water or the like.
The present invention focuses on the above-mentioned problems of the prior art, and aims to provide a fermentation apparatus and a method for producing methane gas that can reduce the consumption of clean water such as clean water.

The embodiment for solving the above problem is a fermentation apparatus having a crushing process section for crushing fermentation raw materials and a fermentation tank, in which the fermentation raw materials crushed in the crushing process section are introduced into the fermentation tank and the fermentation raw materials are fermented in the fermentation tank, and the fermentation apparatus is characterized in that it has a reflux conveying path for returning the moisture in the fermentation tank to the crushing process section.

Here, "moisture" means "containing water." The material returned to the crushing process section by the reflux conveying path contains digestive fluid. In this embodiment, the moisture in the digestive fluid is used to supplement the moisture required during crushing. In many cases, the material returned to the crushing process section by the reflux conveying path is a slurry containing a mixture of solids and water.
The "conveying path" may be a pipeline made of steel pipes, hoses, etc., or may be a conveyor capable of transporting materials containing moisture, such as a screw conveyor or a bucket conveyor.
According to this embodiment, the moisture in the fermentation tank is supplied to the crushing process section, so that the usage of tap water, etc. can be reduced.
In some cases, the crusher chamber can be filled with liquid without using a water supply or the like.

In the above-mentioned aspect, it is preferable that the temperature-controlled circulation conveying path has a heat exchange section in the middle, the temperature-controlled circulation conveying path extracts moisture from the fermentation tank and guides it to the heat exchange section to adjust the temperature, and returns it to the fermentation tank, the temperature-controlled circulation conveying path has a pump, the suction side of the pump is connected to the fermentation tank, the discharge side of the pump is branched, one of the branches is connected to the heat exchange section to form the temperature-controlled circulation conveying path, and the other branch forms the reflux conveying path.

The fermentation apparatus of this embodiment has a temperature-controlled circulation transport path that circulates the contents of the fermenter via a heat exchanger.
The fermentation apparatus of this embodiment can regulate the temperature of the contents using a heat exchanger in the temperature-regulated circulation transport path, so that the fermentation raw materials in the fermenter can be kept at a temperature suitable for fermentation.
In addition, the fermentation apparatus of this embodiment has a small number of parts since the pump for the temperature-controlled circulation conveying path and the pump for the reflux conveying path are shared.

In each of the above-mentioned aspects, it is desirable to have a night soil storage tank for storing animal feces and urine, and a night soil supply and transport path for sending the night soil stored in the night soil storage tank to the crushing process section.

"Animals" includes cows, horses, pigs, sheep and other mammals, and birds such as chickens. "Animals" also includes humans.
Human waste contains a lot of water.
In the fermentation apparatus of this embodiment, the night soil is supplied to the crushing process section, and the moisture in the night soil is utilized to turn the fermentation raw material into a slurry, so that the amount of clean water, etc. used can be reduced.

In each of the above-mentioned aspects, it is preferable that the crushing process section has a coarse crushing device and a wet crushing device, the wet crushing device is disposed downstream of the coarse crushing device, and the fermentation raw material crushed by the coarse crushing device is further crushed by the wet crushing device.

According to this embodiment, food waste and the like are crushed by the coarse crushing device, and then further finely pulverized by the wet crushing device.
In the fermentation apparatus of this embodiment, the fermentation raw material crushed by the coarse crushing device is sent to the wet crushing device, so the fermentation raw material is likely to be caught in the wet crushing device.
That is, when the fermentation raw material is large, the fermentation raw material floats in the wet crushing device and may not be easily caught by the blades of the wet crushing device.
In the fermentation apparatus of this embodiment, the fermentation raw material crushed in the coarse crushing device is sent to the wet crushing device, so that the fermentation raw material is easily caught in the wet crushing device and is crushed finely in the wet crushing device.
According to this embodiment, the fermentation raw material is transported to the fermenter in a finely pulverized state, so that the fermentation proceeds easily.

In the above-mentioned embodiment, the crushing process section has the coarse crushing device and the wet crushing device arranged in upper and lower positions, and is connected directly or via a pipeline, and it is preferable that a water level sensor is provided between the coarse crushing device side breaking section where the fermentation raw materials are broken in the coarse crushing device and the wet side breaking section where the fermentation raw materials are broken in the wet crushing device.

In this embodiment of the fermentation device, a water level sensor is provided between the wet-side rupture section where the fermentation raw material is ruptured, so it can accurately detect whether there is sufficient liquid in the wet-side rupture section.

In each of the above-mentioned aspects, it is desirable to have a storage tank for temporarily storing fermentation raw materials, a first input conveying path connecting the crushing process section and the fermentation tank, a stockpiling conveying path connecting the crushing process section and the storage tank, and a second input conveying path connecting the storage tank and the fermentation tank.

Here, the "storage tank" may be one with an open upper space, such as a pool, or may be one that is sealed, such as a tank.
The fermentation apparatus of this embodiment has a storage tank for temporarily storing the fermentation raw materials. Therefore, when a large amount of the fermentation raw materials is transported from the outside to the fermentation apparatus, the fermentation raw materials can be crushed and stored in the storage tank via the storage transport path.
If necessary, the material can be transported from the storage tank to the fermentation tank via the second input transport path.

In the above-mentioned aspect, it is desirable to have a conveying path switching means, and to be able to carry out full-amount input, in which the entire amount of the fermentation raw materials crushed in the crushing process section is transported to the fermentation tank, partial input, in which a portion of the fermentation raw materials crushed in the crushing process section is transported to the fermentation tank and the remainder is transported to the storage tank, and additional input, in which the entire amount of the fermentation raw materials crushed in the crushing process section and the fermentation raw materials in the storage tank are simultaneously transported to the fermentation tank.

According to this embodiment, even if there is variation in the amount of fermentation raw materials introduced into the fermentation device or the amount of collected food waste, the amount of fermentation raw materials put into the fermentation tank can be leveled out.

The method of using the fermentation apparatus of the above aspect is characterized in that, when the amount of fermentation raw materials crushed in the crushing process section per fixed time is greater than the planned amount of fermentation raw materials to be fed to the fermenter per fixed time, a partial feed is carried out by feeding a portion of the fermentation raw materials crushed in the crushing process section into the fermenter and feeding the remainder into the storage tank, and, when the amount of fermentation raw materials crushed in the crushing process section per fixed time is less than the planned amount of fermentation raw materials to the fermenter per fixed time, an additional feed is carried out by simultaneously feeding the fermentation raw materials in the storage tank in addition to the total amount of fermentation raw materials crushed in the crushing process section into the fermenter.

A "certain period of time" is a relatively long span of time, such as one hour, three hours, or half a day.
According to this aspect, even if there is variation in the amount of fermentation raw material introduced into the fermenter, the amount of fermentation raw material charged into the fermenter can be smoothed out.

Another aspect for solving the same problem is a methane gas production method having a slurrying step of crushing fermentation raw materials including food waste to form a slurry, and a fermentation step of introducing the fermentation raw materials slurried by the slurrying step into a fermenter and fermenting them into methane to obtain methane gas and digestive liquid, characterized in that during the slurrying step, the digestive liquid obtained in the fermenter is added to the fermentation raw materials and crushed.

The fermentation apparatus and methane gas production method of the present invention have the effect of reducing the consumption of clean water, etc.

FIG. 2 is a system diagram of a fermentation apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of the crushing process section of the fermentation apparatus of FIG. 1. FIG. 2 is an enlarged view of the vicinity of the night soil tank of the fermentation apparatus of FIG. 1. FIG. 2 is an enlarged view of the vicinity of the storage tank of the fermentation apparatus of FIG. 1. FIG. 2 is a system diagram of the fermentation apparatus of FIG. 1, showing the flow of the fermentation raw material and digestive liquid when the entire amount of the fermentation raw material is charged into the fermentation tank. FIG. 2 is a system diagram of the fermentation apparatus of FIG. 1, showing the flow of the fermentation raw material when a portion of the fermentation raw material is charged into the fermentation tank. FIG. 2 is a system diagram of the fermentation apparatus of FIG. 1, showing the flow of the fermentation raw materials when the entire amount of the crushed fermentation raw materials is transported into a storage tank. FIG. 2 is a system diagram of the fermentation apparatus of FIG. 1, showing the flow of the fermentation raw material when the fermentation raw material is additionally charged into the fermentation tank. FIG. 2 is a system diagram of the fermentation apparatus of FIG. 1, showing the flow of the fermentation raw material when the temperature of the fermentation raw material in the fermenter is controlled. FIG. 2 is a block diagram of a control device for the fermentation apparatus of FIG. 1.

The embodiments of the present invention will be described further below.
The fermentation apparatus 1 of this embodiment uses food waste and human waste as fermentation raw materials, crushes them, puts them into a fermentation tank 2, and ferments them to produce methane gas.
As shown in FIG. 1, the fermentation apparatus 1 of this embodiment can be divided into a fermentation tank 2 and a fermentation fuel supply section 3.
The fermentation fuel supply section 3 is composed of a crushing process section 10, a sewage storage tank 11, and a storage tank 12.

Each part will be explained below.
The fermentation tank 2 is a sealed tank. An agitation device 17 is provided inside the fermentation tank 2.
The fermenter 2 is equipped with a liquid level gauge, a temperature sensor, a pressure sensor, etc. (none of which are shown) in the same manner as known in the art.
The fermenter 2 also has a number of openings (not shown) which function as inlets for introducing fermentation raw materials and outlets for removing the fermentation raw materials.

The fermenter 2 is provided with a temperature-controlled circulating transport path 20 as shown in FIGS.
The temperature-controlled circulation transport path 20 is a pipe connecting a raw material withdrawal hole 21 and a raw material return hole 22 provided in the fermentation tank 2, and a circulation pump 25 and the secondary side of a heat exchanger 26 are interposed in the middle.
The primary side of the heat exchanger 26 is connected to a water heater (not shown).
A flow path adjustment valve 23 is also provided in the temperature-controlled circulating transport path 20. The flow path adjustment valve 23 can adjust the opening degree by a motor, and can also be fully closed.

The fermentation tank 2 receives food waste and human waste, and causes methane fermentation by the action of anaerobic bacteria, generating methane gas (anaerobic digestion method).
Digestive juices are also produced as a by-product of fermentation.

Next, the crushing process section 10 will be described.
As shown in FIG. 2, the crushing process section 10 has a crushing section 15 which is composed of two crushing devices.
In this embodiment, the crushing section 15 has a dry crushing device 30 and a wet crushing device 31 .
The type and blade structure of the dry crushing device 30 are not limited, but a two-shaft dry crushing device is used in this embodiment. The dry crushing device 30 also functions as a rough crushing device.
The wet crushing device 31 is not limited in type or blade structure, but in this embodiment, a device having a rotary blade provided in a chamber is used.
The wet crushing device 31 is disposed downstream of the dry crushing device 30 .

In the crushing process section 10 of this embodiment, as shown in FIG. 2, a dry crushing device 30 and a wet crushing device 31 are stacked vertically and are directly connected to each other.
That is, the dry crushing device 30 has an inlet and an outlet, and the outlet of the dry crushing device 30 is directly connected to the inlet of the wet crushing device 31. The two may be connected by a tubular member.
The dry crushing device 30 and the wet crushing device 31 are connected together so as not to leak water.

In this embodiment, a water level sensor 33 is provided between the dry crushing device 30 and the wet crushing device 31 .
The water level sensor 33 is located between the rough crusher side breaking section 27 where the fermentation raw material of the dry crusher 30 is broken, and the wet side breaking section 28 where the fermentation raw material of the wet crusher 31 is broken.
The portion where the fermentation raw material is broken is, for example, the portion where the blade and the liner come into contact in a single-shaft crushing device, and the portion where the blades mesh with each other in a twin-shaft crushing device.

Other components constituting the crushing process section 10 include an input conveyor 35 , a discharge conveyor 36 , and a first pressure pump 37 .
The input conveyor 35 is a known bucket conveyor or belt conveyor, and transports food waste and the like brought in by a truck or the like to the input port of the dry crushing device 30.
The discharge conveyor 36 is, for example, a screw conveyor, and sends the slurry fermentation raw material to the first pressure pump 37 .
The first pressure pump 37 is a mixing pump.

Next, the sewage storage tank 11 will be described.
The night soil storage tank 11 is a sealable tank, and has a night soil inlet 38 and night soil discharge sections 72 and 73 .

Next, the storage tank 12 will be described.
The storage tank 12 is composed of an introduction tank 40 and a main storage section 41. The introduction tank 40 is a small tank.
The main reservoir 41 is a large tank. Both the introduction tank 40 and the main reservoir 41 are tanks with an open top, such as a pool.
A lifting conveyor 42 is provided between the introduction tank 40 and the main storage section 41 .
In addition, a screen 43 is provided at the most downstream portion of the lifting conveyor 42.
The main storage section 41 is provided with an agitator 45 .

The storage tank 12 is equipped with a food waste crusher 47 and an inlet conveyor 46 as accessories. The inlet conveyor 46 is a screw conveyor.

Next, the connections between the various members will be described with reference to FIG.
In addition to the piping components shown in the figures, each pipe is provided with a strainer, an on-off valve, a check valve, etc. (not shown).
First, we will explain the line that transports food waste (more precisely, a slurry made by crushing food waste and mixing it with water).
In the fermentation apparatus 1 of this embodiment, the crushing process section 10 and the fermenter 2 are connected by a first input conveying path 50.
Specifically, the first input conveying path 50 is a pipeline that connects the discharge side of the first pressure pump 37 in the crushing process section 10 to the upper side of the fermenter 2 via piping.

The first input conveying path 50 has a branch section 76 in the middle, to which a branch pipe 75 is connected. The branch pipe 75 opens above the storage tank 12.
In this embodiment, a part of the first input conveying path 50 and a branch pipe 75 constitute a stockpiling conveying path 78 connecting the crushing process section 10 and the storage tank 12 as shown in FIG.
The branch pipe 75 which is a part of the stockpiling conveying path 78 may be connected to the side or bottom of the storage tank 12. The stockpiling conveying path 78 may be independent from the first input conveying path 50.

An on-off valve 51 is provided downstream (fermenter 2 side) of the branched portion 76 of the first input conveying path 50. An on-off valve 53 is also provided in the branched pipe 75. The two on-off valves 51, 53 function as a conveying path switching means 57.
The on-off valves 51 and 53 are used to switch the destination of the fermentation raw material and to change the division ratio of the slurry.

The storage tank 12 and the fermentation tank 2 are connected by a second input conveying path 55. A second pressure pump 56 is provided on the second input conveying path 55.

Next, the reflux conveying path 60 that returns the fermentation raw material containing moisture from the fermentation tank 2 to the crushing process section 10 will be described. The fermentation apparatus 1 of this embodiment utilizes the digestive liquid in the fermentation tank 2, and the "fermentation raw material containing moisture" returned from the fermentation tank 2 to the crushing process section 10 also contains a large amount of undigested fermentation raw material, but for ease of explanation, the "fermentation raw material containing moisture" returned from the fermentation tank 2 to the crushing process section 10 will be referred to as the "digestive liquid."

As described above, the fermentation apparatus 1 of this embodiment has the temperature-controlled circulating conveying path 20. The downstream side of the circulating pump 25 of the temperature-controlled circulating conveying path 20 branches off to form a reflux conveying path 60 leading to the crushing process section 10. In this embodiment, the reflux conveying path 60 partially overlaps with the temperature-controlled circulating conveying path 20, and the digestive liquid is sent thereto by the same circulating pump 25.
The fermentation apparatus 1 of this embodiment has a small number of parts because the pipes and the pump are shared.
A flow path adjustment valve 67 is disposed in the return transport path 60. The flow path adjustment valve 67 can adjust the opening degree by a motor, and can also be fully closed.

1 and 2, the end of the return transport path 60 is branched into branch pipes 60c and 60d, which are connected to the crushing section 15 and the first pressure-feed pump 37. An open/close valve 87 is provided in the branch pipe 60d leading to the first pressure-feed pump 37.
The branch pipe 60c is further branched into branches 60a and 60b, which are connected to the dry crushing device 30 and the wet crushing device 31 of the crushing section 15. The branch pipe 60a leading to the dry crushing device 30 is provided with an on-off valve 86.
As described above, the crushing section 15 is a connection between the dry crushing device 30 and the wet crushing device 31, and the end of the return transport path 60 is connected to both the dry crushing device 30 and the wet crushing device 31 (branch paths 60a, 60b) as shown in Figures 1 and 2.

By opening the on-off valve 86 and branching a portion of the digestive fluid sent via the circulating conveying path 60 to the branch path 60a, the digestive fluid can be fed into the dry crushing device 30 and the food waste remaining in the hopper and blades of the dry crushing device 30 can be flushed away.

Next, the piping related to the sewage storage tank 11 will be described.
In this embodiment, one of the night soil discharge sections 72 is connected to a junction 71 of the return transport path 60 by a night soil introduction path 62 .
In this embodiment, the night soil storage tank 11 is connected to the crushing process section 10 by a night soil inlet passage 62 and a return transport passage 60. In this embodiment, the night soil inlet passage 62 and the return transport passage 60 form a night soil supply transport passage 68.
The sewage supply transport path 68 may be a flow path independent of the return transport path 60 .
The night soil inlet path 62 is provided with a night soil pressure pump 63. An on-off valve 65 is provided at a junction 71 with the reflux transport path 60, on the fermenter 2 side. In addition, an on-off valve 66 is also provided in the night soil inlet path 62. The on-off valves 65, 66 function as a switching means 81.
A communication pipe 77 is connected to the other night soil discharge part 73 of the night soil storage tank 11, and the communication pipe 77 opens to the upper part of the introduction tank 40 of the storage tank 12. The communication pipe 77 is provided with an on-off valve 83. The communication pipe 77 may be connected to the side surface or bottom of the storage tank 12.

Next, the clean water circuit 85 will be described.
In the fermentation apparatus 1 of this embodiment, clean water can be supplied to the introduction tank 40 of the storage tank and to the main storage section 41 .
Clean water can also be supplied to the crushing section 15 .

The fermentation apparatus 1 of this embodiment has a control device 70 that controls the entire apparatus.
The control device 70 has a temperature adjustment control section and a return flow rate control section, as shown in FIG.
The temperature control unit detects the temperature inside the fermentation tank 2 using a temperature sensor (not shown) and feeds this back to a water heater (not shown) and a flow path adjustment valve 23 to control the temperature inside the fermentation tank 2.
The return flow rate control section controls the amount of digestive liquid returned from the fermenter 2 based on a signal from the water level sensor 33 .

Next, the flow of fermentation raw materials and the like in the fermentation apparatus 1 will be described.
The fermentation apparatus 1 of this embodiment uses food waste and livestock manure as fermentation raw materials and ferments them in a fermenter 2 to produce methane gas.
Raw food waste as the raw material is collected in urban areas and transported to the fermentation apparatus 1 by trucks A and B.
Livestock manure is provided by farmers, transported by a vacuum truck C, and collected in a manure storage tank 11. Human feces and urine may also be used.

Food waste is usually collected on the crushing process section 10 side and fed into the crushing section 15 by a feed conveyor 35 to be crushed (crushing process).
At this time, the circulation pump 25 is driven, and all the on-off valves (65, 67) provided on the reflux conveying line 60 between the fermenter 2 and the crushing process section 10 are opened.
As a result, as shown by the thick line in FIG. 5, the digestive fluid in the fermenter 2 is supplied to the crushing process section 10 side.

In the crushing section 15, the digestive fluid returned from the fermenter 2 and the newly added food waste are crushed and mixed.
That is, newly added food waste is roughly crushed by the upper dry crushing device 30 and sent to the downstream wet crushing device 31 together with the digestive liquid returned from the fermentation tank 2 .
The chamber of the wet crushing device 31 is filled with digestive fluid and food waste, and the food waste is finely crushed in the liquid. The food waste is agitated by a rotary blade or the like and mixed with the digestive fluid to form a slurry.
If necessary, clean water is supplied to the crushing section 15. However, in the fermentation apparatus 1 of this embodiment, the digestive liquid is returned from the fermentation tank 2 to the crushing section 15, so that even if clean water is supplied, a small amount of clean water is sufficient.

Moreover, when there is human waste in the human waste storage tank 11, the human waste is also supplied to the crushing process section 10.
That is, in this embodiment, the night soil storage tank 11 is connected to the crushing process section 10 by a night soil supply transport path 68 which is constituted by a night soil inlet path 62 and a return transport path 60 .
When the night soil is to be supplied to the crushing process section 10, the on-off valve 66 of the night soil inlet passage 62 is opened to open the series of night soil supply and transport passages 68 extending from the night soil inlet passage 62 to the return transport passage 60. Then, the night soil pressure pump 63 is driven.
As a result, the night soil in the night soil storage tank 11 is supplied to the crushing process section 10 together with the digestive fluid supplied from the fermentation tank 2, as indicated by the bold line in FIG.
Since human waste also contains a lot of water, the chamber of the wet crushing device 31 is filled with liquid and the food waste is crushed into small pieces in the liquid.
In addition, the solid matter in the sewage can be crushed and turned into a slurry.
The digestive fluid that has been finely crushed in the crushing section 15 and returned from the fermentation tank 2 and food waste mixed with human waste are sent to the first pressure pump 37 by the discharge conveyor 36 as shown by the arrow in Figure 5, pressurized by the first pressure pump 37, and fed into the fermentation tank 2 through the first input conveying path 50. If necessary, digestive fluid is also mixed into the first pressure pump 37.

In this embodiment, while the crushing operation is being performed in the crushing process section 10, a water level sensor 33 attached to the crushing section 15 monitors the water level in the crushing section 15.
If the water level in the crushing section 15 falls below the position of the water level sensor 33 , the flow path adjustment valve 67 provided in the return transport path 60 is opened to supply more digestive fluid to the crushing section 15 .
Conversely, when the water level in the crushing section 15 exceeds the position of the water level sensor 33, the opening of the flow path adjustment valve 67 provided in the return transport path 60 is narrowed, thereby reducing the amount of digestive fluid supplied to the crushing section 15.
As a result, the wet crushing device 31 (wet side breaking section 28) is filled with liquid, but the dry crushing device 30 (coarse crushing device side breaking section 27) is not filled with liquid, so that food waste that floats on water does not float up inside the dry crushing device 30, and the food waste can be crushed in the dry crushing device 30 to turn it into a slurry.

The above is the flow of fermentation materials under normal circumstances, but the amount of food waste collected varies.
For example, during the day, workers who collect food waste are at work and the amount of food waste collected is large.
In contrast, at night, there are fewer workers on duty and less food waste is collected.
Furthermore, the amount of food waste and human waste to be put into the fermenter 2 also varies.
In other words, there are variations in both the demand for food waste etc. required for the fermenter 2 and the supply, i.e., the amount of food waste etc. collected.

In this embodiment, as a measure to level out the relationship between demand and supply, it is possible to switch between full-amount input, in which the entire amount of the fermentation raw materials crushed in the crushing process section 10 is transported to the fermentation tank 2, partial input, in which a portion of the fermentation raw materials crushed in the crushing process section 10 is transported to the fermentation tank 2 and the remainder is transported to the storage tank 12, and additional input, in which the entire amount of the fermentation raw materials crushed in the crushing process section 10 and the fermentation raw materials in the storage tank 12 are simultaneously transported to the fermentation tank 2.
It is also possible to carry out storage of the entire amount of the fermentation raw material crushed in the crushing process section 10 into the storage tank 12 .

In a preferred method of use, the destination of the fermentation raw material is determined based on whether the amount of fermentation raw material being crushed per given time in the crushing process section 10 is greater than the planned amount of fermentation raw material to be fed to the fermenter 2 per given time.
For example, a fixed time period is set to three hours or half a day, and the amount of fermentation raw material crushed in the crushing process section 10 during this time period is compared with the amount of fermentation raw material to be charged into the fermenter 2.
When the amount of fermentation raw material being crushed in the crushing process section 10 per certain time period is greater than the planned amount of fermentation raw material to be fed to the fermentation tank 2 per certain time period, a partial feeding is carried out in which a portion of the crushed fermentation raw material is fed to the fermentation tank 2 and the remainder is fed to the storage tank 12.
When the amount of fermentation raw material being crushed in the crushing process section 10 per certain time period is less than the planned amount of fermentation raw material to be added, additional addition is carried out by simultaneously transporting the fermentation raw material in the storage tank 12 to the fermentation tank 2 in addition to the entire amount of the crushed fermentation raw material.
The redirection of the fermentation raw material may be performed automatically or manually.

For example, if the amount of collected food waste is greater than the amount of food waste to be supplied to the fermentation tank 2, a portion of the food waste crushed in the crushing process section 10 is sent to the storage tank 12 via the stockpiling transport path 78 (partial input), as shown by the arrow in Figure 6.
That is, the on-off valve 53 provided on the branch pipe 75 is opened to open the series of stockpiling conveying paths 78 that run from the first pressure-feed pump 37 of the crushing process section 10 to the branch pipe 75 .
As a result, as indicated by the arrow in FIG. 6 , a portion of the food waste passing through the first input conveying path 50 enters the branch pipe 75 and is introduced into the storage tank 12 .

When the fermentation tank 2 is full (when there is a lot of undigested material) and there is no need to supply new food waste, the opening/closing valve 51 of the first input conveying path 50 is closed, and as shown by the bold line in Figure 7, the food waste crushed in the crushing process section 10 is introduced in its entirety into the storage tank 12 via the stockpiling conveying path 78 (all amount stored).

If the amount of collected food waste is even greater, truck B is parked next to storage tank 12 and placed in storage tank 12.
The food waste discharged from the truck B is finely crushed by the food waste crusher 47. At this time, clean water is supplied to the food waste crusher 47 from the clean water circuit 85, and the food waste is mixed with the clean water to form a slurry. The slurry-like food waste is then fed by the introduction conveyor 46 into the introduction tank 40 of the storage tank 12.
The slurry-like garbage in the introduction tank 40 is then transported to a screen 43 by a lifting conveyor 42, where the coarse garbage is removed, and only the finely crushed garbage is stored in the storage tank 12.

Conversely, when the stock of food waste is low, the crushed food waste and human waste stored in the storage tank 12 are supplied to the fermentation tank 2, as shown by the thick line in FIG.
That is, as shown by the thick line in Figure 8, the entire amount of food waste crushed in the crushing process section 10 is supplied to the fermentation tank 2, and in addition, the food waste in the storage tank 12 is also supplied to the fermentation tank 2 (additional input).
In addition, if the stock of food waste is completely depleted, only the crushed food waste and human waste stored in the storage tank 12 are supplied to the fermentation tank 2.

The temperature of the fermentation raw material in the fermenter 2 is controlled by the temperature-regulated circulating transport path 20 to carry out methane fermentation (fermentation process). That is, as shown by the thick line in Fig. 9, the fermentation raw material in the fermenter 2 is constantly taken out to the outside by the temperature-regulated circulating transport path 20 and the temperature is regulated by the heat exchanger 26.
The temperature of the hot water on the primary side of the heat exchanger 26 and the opening degree of the flow path adjustment valve 23 are controlled by feeding back the temperature detected by a temperature sensor attached to the fermenter 2, thereby controlling the temperature inside the fermenter 2 to a constant value.

The fermentation apparatus 1 of the embodiment described above is provided with a storage tank for temporarily storing the crushed fermentation raw materials, in consideration of the fact that there is variation between the demand for food waste etc. required for the fermentation tank 2 and the supply, i.e., the amount of collected food waste etc. This technology can also be applied to fermentation apparatuses of other configurations.
That is, the fermentation apparatus 1 of this embodiment has a crushing process section 10 that crushes fermentation raw materials, and a fermentation tank 2, and the fermentation apparatus 1 introduces the fermentation raw materials crushed in the crushing process section 10 into the fermentation tank 2 and ferments the fermentation raw materials in the fermentation tank 2. The fermentation apparatus 1 has a storage tank 12 that temporarily stores the fermentation raw materials, a first input conveying path 50 that connects the crushing process section 10 and the fermentation tank 2, a stockpiling conveying path 78 that connects the crushing process section 10 and the storage tank 12, and a second input conveying path 55 that connects the storage tank 12 and the fermentation tank 2.

A preferred method of using this embodiment is as follows.
That is, during the daytime, when a large amount of food waste and human waste is received, a portion of the crushed fermentation raw materials is stored in the storage tank 12.
At night, when the amount of food waste and the like being received decreases, the fermentation raw materials stored in the storage tank 12 are removed and charged into the fermentation tank 2.
If a configuration were adopted in which all of the received fermentation raw materials were stored in the storage tank 12 before being poured into the fermenter 2, it would be necessary to receive extra food waste even after the amount required for the night has been secured. For this reason, the storage tank 12 would need to be considerably large.
In contrast, in the method of this embodiment, when the amount of fermentation raw material added to the fermenter 2 during the day exceeds the required amount, the fermentation raw material is diverted to the storage tank 12 side.
According to the configuration of this embodiment, there is no need to make the volume of the storage tank 12 excessively large.

Reference Signs List 1 Fermentation device 2 Fermentation tank 10 Crushing process section 11 Human waste storage tank 12 Storage tank 15 Crushing section 20 Temperature-controlled circulating transport path 25 Circulation pump 26 Heat exchanger 30 Dry crushing device (rough crushing device)
31 Wet crushing device 33 Water level sensor 50 First input conveying path 55 Second input conveying path 57 Conveying path switching means 60 Return conveying path 68 Human waste supply conveying path 78 Stockpiling conveying path

Claims (9)

A fermentation apparatus having a crushing process section for crushing a fermentation raw material and a fermentation tank, the fermentation raw material crushed in the crushing process section is introduced into the fermentation tank, and the fermentation raw material is fermented in the fermentation tank,
A fermentation apparatus comprising: a reflux conveying passage for returning water in the fermentation tank to the crushing process section. A temperature-controlled circulation transport path is provided, the temperature-controlled circulation transport path has a heat exchanger in the middle, the temperature-controlled circulation transport path extracts moisture from the fermenter, guides it to the heat exchanger to adjust the temperature, and returns it to the fermenter,
2. The fermentation apparatus according to claim 1, further comprising a pump, the suction side of which is connected to the fermentation tank and the discharge side of which is branched, one of which is connected to the heat exchanger to form the temperature-controlled circulation transport path, and the other of which is connected to the heat exchanger to form the reflux transport path. The fermentation apparatus according to claim 1 or 2, characterized in that it has a night soil storage tank for storing animal feces and urine, and has a night soil supply and transport path for sending the night soil stored in the night soil storage tank to the crushing process section. The fermentation apparatus according to any one of claims 1 to 3, characterized in that the crushing process section has a coarse crushing device and a wet crushing device, the wet crushing device is disposed downstream of the coarse crushing device, and the fermentation raw materials crushed by the coarse crushing device are further crushed by the wet crushing device. In the crushing process section, the rough crushing device and the wet crushing device are arranged at upper and lower positions, and are connected directly or via a pipeline;
5. The fermentation apparatus according to claim 4, wherein a water level sensor is provided between a coarse crusher-side breaking section where the fermentation raw materials are broken in the coarse crusher and a wet-side breaking section where the fermentation raw materials are broken in the wet crusher. A storage tank is provided for temporarily storing fermentation raw materials.
A first input conveying path connecting the crushing process section and the fermentation tank;
A stockpiling transport path connecting the crushing process section and the storage tank;
6. The fermentation apparatus according to claim 1, further comprising a second input conveying path connecting the storage tank and the fermentation tank. A conveying path switching means is provided,
A total amount of the fermentation raw material crushed in the crushing process section is introduced into the fermenter;
A partial charge in which a part of the fermentation raw material crushed in the crushing process section is carried into the fermentation tank and the remainder is carried into the storage tank;
The fermentation apparatus according to any one of claims 6 to 8, characterized in that it is possible to carry out additional charging by simultaneously transporting the fermentation raw materials in the storage tank to the fermentation tank in addition to the total amount of the fermentation raw materials crushed in the crushing process section. When the amount of the fermentation raw material being crushed in the crushing process section per certain time is greater than the planned amount of the fermentation raw material to be charged to the fermenter per certain time, a partial charge is carried out in which a part of the fermentation raw material crushed in the crushing process section is carried into the fermenter and the remaining part is carried into the storage tank,
8. The method for using a fermentation apparatus according to claim 7, characterized in that, when the amount of fermentation raw materials being crushed in the crushing process section per certain time period is less than the planned amount of fermentation raw materials to be fed to the fermenter per certain time period, additional feeding is carried out by simultaneously feeding the fermentation raw materials in the storage tank and the total amount of fermentation raw materials crushed in the crushing process section into the fermenter tank. A method for producing methane gas, comprising: a slurrying step of crushing and slurrying a fermentation raw material containing food waste; and a fermentation step of introducing the slurried fermentation raw material into a fermenter and subjecting it to methane fermentation to obtain methane gas and a digestive liquid,
A method for producing methane gas, comprising the steps of adding the digested liquid obtained in the fermenter to the fermentation raw material and crushing the digested liquid during the slurrying step.

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