JP6735220B2 - Biogas generator - Google Patents

Description

The present invention relates to a biogas generator.

Conventionally, a receiving portion for receiving waste liquid for crushing food waste is provided, and a solid-liquid separation tank for separating and separating the waste liquid for crushing food waste is provided, and the liquid phase separated in the solid-liquid separation tank is drained to the outside. The solid-liquid separation tank is provided with a drainage section, and an anaerobic fermentation tank that receives the precipitate separated by the solid-liquid separation tank and biogasifies it is settled from the solid-liquid separation tank to the anaerobic fermentation tank. The advection part for advancing the substance is provided, and the advection part is closed by the precipitate between the solid-liquid separation tank and the anaerobic fermentation tank to separate the solid-liquid separation from the anaerobic fermentation tank of solid components. While providing a throttling part capable of preventing backflow to the tank, the precipitate is transferred to the anaerobic fermentation tank through the throttling portion, the excess liquid phase of the anaerobic fermentation tank through the throttling portion A sediment advancing mechanism that enables return to the solid-liquid separation tank is provided in the anaerobic fermentation tank, and the anaerobic fermentation tank has a wastewater treatment device provided with a biogas extraction path for taking out the produced biogas to the outside (for example, , Patent Document 1).

This wastewater treatment equipment is a stirring pump that supplies anaerobic gas to a storage tank, a pump for a gas lifter that returns the anaerobic gas to a return pipe, and a diffuser that supplies the anaerobic gas to an air diffuser that diffuses the anaerobic gas into the anaerobic fermentation space. It includes an air pump and a stirring pump for supplying anaerobic gas to the solid-liquid separation tank.

Further, there is a continuous operation apparatus for methane fermentation having a non-powered stirring mechanism. The fermenter is divided into four chambers by a partition plate, a U-shaped tube is inserted into the partition plate between the first chamber and the second chamber, and the gas phase part of the first chamber pushes down the liquid surface by biogas. When the liquid level of the first chamber reaches the bottom of the U-shaped tube, the biogas stored in the gas phase of the first chamber moves to the second chamber through the U-shaped tube, and the fermented liquid enters the first chamber. The liquid level in the first chamber rises, and the liquid levels in the second to fourth chambers descend. The liquid flow generated at this time causes stirring in the fermenter. However, the raw material (simulated food waste) is supplied to the boundary between the first chamber and the second chamber at the bottom of the fermenter by a timer-controlled pump (see Non-Patent Document 1, for example).

JP, 2013-027851, A

Development of a new low-cost methane fermentation reactor with a non-powered stirring mechanism, Takuro Kobayashi, Shin Minami Usami, Yu Yu Li, Journal of Japan Society on Water Environment Vol. 33, No. 12, pp. 201-208 (2010)

By the way, the wastewater treatment device described in Patent Document 1 is suitable for driving an aeration pump that forms a gas-liquid multiphase flow in an anaerobic fermentation tank when biogas is generated from a biomass material that is renewable energy. Since electric power is required, there is a problem that energy recovery efficiency is low.

Further, since the continuous operation apparatus for methane fermentation described in Non-Patent Document 1 uses a pump to supply the biomass raw material to the fermenter, there is room for improvement in energy recovery efficiency.

Then, it aims at providing the biogas generator with high energy recovery efficiency.

A biogas generator according to an embodiment of the present invention is a biogas generator including a siphon-type fermenter that stores a fermentation liquid containing a biomass raw material in the presence of microorganisms to generate biogas, The tank is provided with a raw material inlet provided in the lower portion of the fermentation tank, an outlet provided in the upper portion of the fermentation tank at a position separated from the raw material inlet in a plan view, and an outlet for discharging the biogas, in a plan view. At a position between the raw material inlet and the outlet, it extends from the top plate of the fermentation tank to a first height position before a first predetermined distance of the bottom plate inside the fermentation tank and has a through hole. A space that is a first partition and that is located above the through hole is sealed, and is communicated with the first tank at the bottom of the fermentation tank and the first tank in which the raw material inlet is provided in the lower portion. At the same time, a first partition wall that divides the inner space of the fermentation tank into a second tank having the discharge port provided on the upper side and a lower end of the first height position of the first partition wall, and the first height A baffle plate that extends obliquely toward the second tank side to a second height position that is lower than the position, and that obstructs the outflow of the solids contained in the fermentation liquor to the second tank side; A U-shaped tube having an end and a second end, wherein the U-shaped pipe is inserted into the through hole of the first partition wall at an intermediate portion between the first end and the second end, and A U-tube having one end and the second end extending upwardly.

A biogas generator with high energy recovery efficiency can be provided.

It is a sectional view showing biogas generator 100. It is a figure which shows the A1-A2 arrow cross section of the biogas generator 100 shown in FIG. It is a figure which shows the process in which the biogas generator 100 produces|generates biogas in steps. It is a figure which shows the process in which the biogas generator 100 produces|generates biogas in steps. It is a figure which shows the general methane fermentation system 500. It is a figure which shows an electric power balance.

Hereinafter, an embodiment to which the biogas generator of the present invention is applied will be described.

<Embodiment>
FIG. 1 is a sectional view showing a biogas generator 100. FIG. 2 is a view showing a cross section taken along line A1-A2 of the biogas generator 100 shown in FIG. 1 shows a cross section of the entire biogas generator 100 at a position corresponding to the cross section taken along the line B1-B2 in FIG.

1 and 2, an XYZ coordinate system, which is an orthogonal coordinate system, is defined as shown in the figure. Here, as an example, the XY plane is the horizontal plane, and the Z-axis positive direction is the vertically upper direction. The plan view refers to viewing the XY plane from the Z-axis positive direction.

The biogas generator 100 includes a treatment tank 110 as a main component. The biogas generator 100 includes, in addition to the treatment tank 110, a device for treating biogas generated in the treatment layer 110, a device for treating wastewater of the treatment layer 110, and the like, but they are omitted in FIG. 1.

The processing tank 110 has a bottom plate 111, a side wall 112, a top plate 113, a partition plate 114, partition walls 115, 116 and 117, a baffle plate 115X, a U-shaped tube 118, a baffle plate 119A, a partition plate 119B, and a partition board 119C.

As shown in FIG. 2, the bottom plate 111 is a rectangular plate-shaped member in a plan view, and is located at the bottom of the processing bath 110. The bottom plate 111 is the bottom of the processing bath 110.

The side wall 112 has side walls 112A, 112B, 112C, and 112D (see FIG. 2). The side walls 112A, 112B, 112C, and 112D are arranged along the four sides of the bottom plate 111 in this order in a rectangular ring shape in plan view. Therefore, in FIG. 1, only the side walls 111A and 111C are shown in cross section.

The side walls 112A, 112B, 112C, and 112D are rectangular plate-shaped members, and surround the four side surfaces of the processing bath 110. The side wall 112A is provided with an inlet 112E through which a slurry containing a biomass raw material flows into the processing tank 110. The inflow port 112E is provided at a position near the top plate 113 in the Z-axis direction.

Further, the side wall 112C is provided with a discharge port 112F for discharging the liquid. The outlet 112F is provided at a position near the top plate 113 in the Z-axis direction.

In the following description, the side walls 112A, 112B, 112C, and 112D will be simply referred to as side walls 112 unless otherwise specified.

The top plate 113 is a rectangular plate-shaped member in a plan view, and is provided on the upper surface of the processing tank 110. Here, as an example, the size of the top plate 113 in plan view is equal to that of the bottom plate 111. The top plate 113 is provided with a discharge port 113A for discharging biogas.

The bottom plate 111, the side wall 112, and the top plate 113 are made of metal or resin, for example, and are fixed to each other to form a rectangular parallelepiped internal space. When the bottom plate 111, the side wall 112, and the top plate 113 are made of metal, they may be fixed by welding, screwing, or the like. When the bottom plate 111, the side wall 112, and the top plate 113 are made of resin, they may be fixed by adhesion, screwing, or the like. Further, the surfaces of the bottom plate 111, the side walls 112, and the top plate 113 may be subjected to painting or antiseptic treatment, if necessary.

The partition plate 114, the partition walls 115, 116 and 117, the baffle plate 115X, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C are internal spaces constructed by the bottom plate 111, the side wall 112, and the top plate 113. It is installed in. The partition plate 114, the partition walls 115, 116 and 117, the baffle plate 115X, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C are made of metal or resin, for example.

When the partition plate 114, the partition walls 115, 116 and 117, the baffle plate 115X, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C are made of metal, they may be fixed by welding or screwing. When the partition plate 114, the partition walls 115, 116 and 117, the baffle plate 115X, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C are made of resin, they may be fixed by adhesion or screwing. If necessary, the surfaces of the partition plate 114, the partition walls 115, 116 and 117, the baffle plate 115X, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C may be painted or antiseptic treated. Good.

The partition plate 114 is a plate-shaped member arranged in parallel with the YZ plane inside the processing tank 110. The partition plate 114 extends from the position of the height h1 from the bottom plate 111 to the top plate 113 in the Z-axis direction. The height h1 is an example of the second height, and the length from the bottom plate 111 to the lower end 114A is an example of the second predetermined distance.

Further, the partition plate 114 extends between the side wall 112B and the side wall 112D in the Y-axis direction. The lower end 114A of the partition plate 114 is located at a height h1 from the bottom plate 111 in the Y-axis direction between the side wall 112B and the side wall 112D.

Three sides of the partition plate 114 other than the lower end 114A are fixed to the side walls 112B and 112D and the top plate 113.

The partition plate 114 having such a configuration partitions the internal space of the processing bath 110 into the X-axis negative direction side and the X-axis positive direction side at a position higher than the height h1 from the bottom plate 111. Further, the partition plate 114 has a slit 114B having a height h1 at the bottom of the internal space of the processing bath 110. The slit 114B has a height of h1 and is provided between the side wall 112B and the side wall 112D.

In the treatment tank 110, the X-axis negative direction side of the partition plate 114 is referred to as a pretreatment tank 120, and the X-axis positive direction side of the partition plate 114 is referred to as a fermentation tank 130. The pretreatment tank 120 and the fermentation tank 130 extend between the bottom plate 111 and the top plate 113 in the Z-axis direction, and the pretreatment tank 120 and the fermentation tank 130 are located below the partition plate 114. The slits 114B communicate with each other.

The slit 114B is an example of an opening provided in the lower portion of the pretreatment tank 120 and an example of a raw material inlet provided in the lower portion of the fermentation tank 130.

That is, the treatment tank 110 includes the pretreatment tank 120 and the fermentation tank 130. The pretreatment tank 120 and the fermentation tank 130 are partitioned by a partition plate 114. Such a treatment tank 110 is one in which the pretreatment tank 120 and the fermentation tank 130 are integrated.

The pretreatment tank 120 may be regarded as an adjustment tank or a solid-liquid separation tank. The fermenter 130 may be regarded as an anaerobic fermenter.

The pretreatment tank 120 is a tank for storing a slurry containing a biomass raw material and performing a pretreatment for precipitating the biomass raw material. Since no microorganisms exist inside the pretreatment tank 120, biogas is not produced.

The slurry containing the biomass raw material is a liquid obtained by mixing the biomass raw material with water, and is called a substrate. In FIG. 1, the substrate 10 is shown as a dark dot pattern. The biomass raw material contained in the substrate 10 precipitates in the lower part of the pretreatment tank 120. In FIG. 1, the precipitate 11 is shown in dark gray. The substrate 10 is supplied to the fermentation tank 130 from the slit 114B of the pretreatment tank 120, and becomes the fermentation liquid 20 inside the fermentation tank 130. In FIG. 1, the fermented broth 20 is shown with a thin dot pattern. The fermentation liquid 20 is mixed with microorganisms that decompose the biomass raw material.

Here, the biomass raw material is, for example, an organic substance such as food waste, sewage sludge, and livestock waste, and by contacting with microorganisms under anaerobic conditions, the microorganisms decompose to produce biogas. It is a raw material that is generated.

The biogas is a gas generated by decomposing the biomass material inside the fermenter 130. Here, a mode in which methane gas is generated from a biomass material containing food waste will be described. About 55% to about 65% of biogas generated in the fermenter 130 is methane gas, and the rest is carbon dioxide or the like. ..

The fermenter 130 is a tank that is supplied with microorganisms under anaerobic conditions and that uses the substrate 10 supplied from the pretreatment tank 120 via the slit 114B to generate biogas. Fermenter 130 has a siphon type configuration.

Further, although only the main constituent elements are shown in FIG. 1, illustration thereof is omitted, but the fermenter 130 is connected to a hot water circulation pump. The fermented liquid 20 is kept at a temperature suitable for fermentation (for example, a temperature in the range of 30°C to 60°C, for example, 35°C or 55°C) by a hot water circulation pump.

Inside the fermenter 130, the partition walls 115, 116, and 117 are provided in this order from the X-axis negative direction side to the X-axis positive direction side.

Here, it is assumed that the inner space of the fermenter 130 is divided into four chambers 131, 132, 133, and 134 by the three partition walls 115, 116, and 117. The four chambers 131, 132, 133, and 134 are in communication with each other.

Further, the liquid surface of the fermentation liquid 20 inside the chamber 131 is shown as a liquid surface 20A. Further, the liquid surfaces of the fermented liquid 20 inside the chambers 132 to 134 are equal to each other, and are therefore shown as liquid surface 20B. Here, as an example, the liquid level 20A of the fermentation liquid 20 in the chamber 131 is equal to the liquid level 10A of the substrate 10 in the pretreatment tank 120, and the liquid level 20A and the liquid level 20B of the fermentation liquid 20 are also equal. ..

The partition wall 115 is a plate-shaped member disposed inside the processing tank 110 in parallel with the YZ plane. The partition 115 is an example of a first partition.

The partition wall 115 extends from the bottom plate 111 at a height h2 to the top plate 113 in the Z-axis direction. Further, the partition wall 115 extends between the side wall 112B and the side wall 112D in the Y-axis direction. The lower end 115A of the partition wall 115 is located at a height h2 from the bottom plate 111 in the Y-axis direction between the side wall 112B and the side wall 112D. The height h2 is an example of a first height, and the distance from the bottom plate 111 to the lower end 115A is an example of a first predetermined distance.

Three sides of the partition wall 115 other than the lower end 115A are fixed to the side walls 112B and 112D and the top plate 113. A baffle 115X is connected to the lower end 115A.

Further, the partition wall 115 is provided with a through hole 115B. The through hole 115B is an opening that penetrates the plate-shaped partition wall 115 in the X-axis direction (the thickness direction of the partition wall 115). The position of the through hole 115B in the Y-axis direction is, for example, the center of the length of the partition wall 115 in the Y-axis direction. A U-shaped tube 118 is inserted through the through hole 115B.

The partition wall 115 having such a structure partitions the internal space of the fermenter 130 into the X-axis negative direction side and the X-axis positive direction side at a position higher than the height h2 from the bottom plate 111. Further, the partition wall 115 has a slit 115C having a height h2 at the bottom of the internal space of the fermentation tank 130. The slit 115C has a height h2 and is provided between the side wall 112B and the side wall 112D.

Here, in the fermenter 130, the X-axis negative direction side of the partition 115 is referred to as a chamber 131, and the X-axis positive direction side of the partition 115 and the X-axis negative direction side of the partition 116 are referred to as a chamber 132. The chamber 131 and the chamber 132 extend between the bottom plate 111 and the top plate 113 in the Z-axis direction, and the chamber 131 and the chamber 132 are connected by a slit 115C located below the partition wall 115. There is. The chamber 131 is an example of a first tank, and the chamber 132 is an example of a second tank.

Further, above the lower end 115A of the partition wall 115 in the chamber 131, except that the partition plate 114, the top plate 113, the partition wall 115, and the fermentation liquid 20 are connected to the chamber 132 by the U-shaped tube 118. It is configured so that a space to be sealed by the liquid surface 20A of

The baffle plate 115X is a plate-shaped member that is connected to the lower end 115A of the partition wall 115 and extends obliquely downward toward the chamber 132. Similar to the partition wall 115, the baffle plate 115X extends from the end on the Y axis negative direction side to the end on the Y axis positive direction side inside the fermentation tank 130. The baffle plate 115X is provided to obstruct (suppress) the solid matter contained in the fermentation liquid 20 from flowing out from the chamber 131 to the chamber 132. Here, the solid matter is the precipitate 11 (biomass raw material or the like) contained in the substrate 10 and also includes foreign matters other than the biomass raw material.

In order to efficiently generate the biogas in the chamber 132, it is preferable to create a situation in which the precipitate 11 is more present in the chamber 131. When the fermented liquid 20 flows from the chamber 131 to the chamber 132, the precipitate 11 collides with the baffle plate 115X, or the baffle plate 115X suppresses the flow force of the fermented liquid 20. By creating a situation in which the heavy sediment 11 is difficult to flow into the chamber 132, it is possible to create a situation in which more sediment 11 exists in the chamber 131.

Further, here, for convenience of description, the boundary between the chamber 131 and the chamber 132 is described as the partition wall 115, but the baffle plate 115X extends obliquely downward from the lower end 115A of the partition wall 115 toward the chamber 132 side. Even in the chamber 132, if the precipitate 11 can be retained in the space below the baffle plate 115X, the generated biogas can be guided to the chamber 131, and the biogas can be efficiently supplied to the chamber 131. Can be collected in the space above.

The height h3 of the lower end 115X1 of the baffle plate 115X with respect to the bottom plate 111 is lower than the height h2 of the lower end 115A of the partition wall 115, and may be set to an optimum value according to the dimensions of each part of the fermentation tank 130 and the like. The angle θ1 of the baffle plate 115X with respect to the partition wall 115 is preferably about 30 to 60 degrees, and most preferably 45 degrees.

Such a baffle plate 115X may be regarded as a part of the partition wall 115. A slit is formed between the lower end 115X1 of the baffle plate 115X and the bottom plate 111.

The chamber 131 communicates with the pretreatment tank 120 through the slit 114B, and the substrate 10 is supplied from the pretreatment tank 120. Inside the fermenter 130, the substrate 10 is supplied from the chamber 131 to the entire fermenter 130 via the chamber 132, and biogas is generated.

The biogas generated in the chamber 131 is stored in the space sealed by the partition plate 114 on the upper side of the chamber 131, the top plate 113, the partition wall 115, and the liquid surface 20A of the fermentation liquid 20.

The chamber 132 is supplied with the substrate 10 from the chamber 131 and produces biogas. The biogas generated in the chamber 132 is discharged from the discharge port 113A through the space above the liquid surface 20B of the fermentation liquid 20 in the chambers 132 to 134.

The partition 116 is a plate-shaped member that is arranged in parallel with the YZ plane inside the processing bath 110. The partition wall 116 is an example of a second partition wall.

The partition wall 116 extends from the bottom plate 111 to the height h4 in the Z-axis direction. The partition 116 extends between the side wall 112B and the side wall 112D in the Y-axis direction. The upper end 116A of the partition wall 116 is located at a height h4 from the bottom plate 111 in the Y-axis direction between the side wall 112B and the side wall 112D.

Three sides of the partition 116 other than the upper end 116A are fixed to the side walls 112B and 112D and the bottom plate 111.

The partition wall 116 having such a structure partitions the internal space of the fermentation tank 130 into the X-axis negative direction side and the X-axis positive direction side at a position lower than the height h4 from the bottom plate 111.

Since the partition wall 116 contributes to the formation of a vortex of the fermentation liquid 20 when stirring the fermentation liquid 20 in the fermenter 130 by the siphon effect described later, it is very effective to optimize the height of the partition wall 116. is there. The height h4 of the partition wall 116 may be lower than the middle portion 118C of the U-shaped tube 118 or higher than the middle portion 118C of the U-shaped tube 118, but the height h4 of the middle portion 118C of the U-shaped tube 118 is smaller than that of the middle portion 118C. Most preferably, the height is the same as the center (the center in the radial direction of the pipe and the center in the height direction of the width of the pipe).

Here, in the fermenter 130, the X-axis negative direction side of the partition wall 116 and the X-axis positive direction side of the partition wall 115 are referred to as a chamber 132, and the X-axis positive direction side of the partition wall 116 and the X-axis side of the partition wall 117. The negative side is referred to as the chamber 133. The chamber 132 and the chamber 133 extend between the bottom plate 111 and the top plate 113 in the Z-axis direction, and the chamber 132 and the chamber 133 are connected by the space above the partition 116.

The substrate 133 is supplied to the chamber 133 via the chamber 132 to generate biogas. The biogas generated in the chamber 133 is discharged from the discharge port 113A through the space above the liquid level B of the fermentation liquid 20 in the chambers 132 to 134.

The partition wall 117 is a plate-shaped member that is arranged in parallel with the YZ plane inside the processing bath 110. The partition 117 is an example of a second partition. The partition wall 117 extends in the Z-axis direction from a position at a height h3 from the bottom plate 111 to a position at a height h5 below the top plate 113.

Further, the partition wall 117 extends from the side wall 112B to the side wall 112D in the Y-axis direction. The lower end 117A of the partition wall 117 is located at a height h3 from the bottom plate 111 in the Y-axis direction between the side wall 112B and the side wall 112D. An upper end 117B of the partition wall 117 is located below the top plate 113 by a height h5 along the Y-axis direction between the side wall 112B and the side wall 112D.

Two sides of the partition wall 117 other than the lower end 117A and the upper end 117B are fixed to the side walls 112B and 112D.

The partition wall 117 having such a configuration has the internal space of the fermenter 130 at the position higher than the height h3 from the bottom plate 111 and lower than the top plate 113 by the height h5, in the X-axis negative direction side and the X-axis direction. It is divided into the positive direction side.

Further, the partition wall 117 has a slit 117C having a height h3 at the bottom of the internal space of the fermentation tank 130. The slit 117C has a height of h3 and is provided between the side wall 112B and the side wall 112D. Moreover, the partition wall 117 has a slit 117</b>D having a height h<b>5 in the upper part of the internal space of the fermentation tank 130. The slit 117D has a height of h5 and is provided between the side wall 112B and the side wall 112D.

Here, in the fermenter 130, the X-axis negative direction side of the partition wall 117 and the X-axis positive direction side of the partition wall 116 are referred to as a chamber 133, and the X-axis positive direction side of the partition wall 117 is referred to as a chamber 134. The chamber 133 and the chamber 134 extend between the bottom plate 111 and the top plate 113 in the Z-axis direction, and the chamber 133 and the chamber 134 are formed by the slits 117C and 117D located above and below the partition wall 117, respectively. It is in communication.

Further, a discharge port 112F for discharging the fermented liquid 20 is provided above the side wall 112C of the chamber 134, and a partition plate 119B and a partition board 119C are provided inside the chamber 134. The partition plate 119B and the partition board 119C are provided to guide the fermentation liquid 20 to the discharge port 112F.

The partition plate 119B has plates 119B1 and 119B2. The plate 119B1 has an upper end fixed to the top plate 113, and extends from the side wall 112B to the side wall 112D in the Y-axis direction and in the Z-axis negative direction at the center of the width of the chamber 134 in the X-axis direction. ..

The plate 119B2 is attached to the lower end of the plate 119B1. Like the plate 119B1, the plate 119B1 extends from the side wall 112B to the side wall 112D in the Y-axis direction, and when viewed from the Y-axis negative direction side to the Y-axis positive direction side in the XZ plane, with respect to the Z-axis positive direction. It is angled to make 135 degrees in a clockwise direction.

The partition plate 119B constructed by such plates 119B1 and 119B2 is sized so that the lower end thereof is immersed in the fermentation liquid 20.

The partition board 119C has, for example, an isosceles right triangle in the XZ cross section, and is attached to the side wall 112C. The position in the Z-axis direction where the partition board 119C is attached to the side wall 112C is the position where the partition board 119C is immersed in the fermentation liquid 20 (below the liquid surface 20B).

The partition board 119C extends from the side wall 112B to the side wall 112D in the Y-axis direction. The tip 119C1 of the partition board 119C is a portion corresponding to the right-angled vertex of the shape of an isosceles right triangle in the XZ section, and a slit for guiding the fermented liquid 20A to the discharge port 112F is formed between the tip and the lower end of the plate 119B2. doing.

Of the internal space of the chamber 134, the liquid level of the fermented liquid 20 in the space surrounded by the partition plate 119B and the partition board 119C as described above is surrounded by the partition plate 119B and the partition board 119C of the internal space of the chamber 134. There is a case where it is different from the liquid surface 20B in a space other than the space to be opened.

The substrate 10 is supplied to the chamber 134 via the chambers 132 and 133 to generate biogas. The biogas generated in the chamber 134 is discharged from the discharge port 113A through the space above the liquid surface 20B of the fermentation liquid 20 in the chambers 132 to 134.

Further, in the chamber 134, the same amount of the fermentation liquid 20 as the substrate 10 supplied from the pretreatment tank 120 to the fermentation tank 130 is discharged from the discharge port 112F.

In the state shown in FIG. 1, the liquid level 20A and the liquid level 20B are balanced, and the heights of the liquid level 20A and the liquid level 20B are equal. Such a balanced state also occurs after the siphon effect described later occurs.

In the fermenter 130, in a state where the liquid surface 20A and the liquid surface 20B are balanced, the liquid surfaces 20A and 20B are higher than the partition wall 116 and the intermediate portion 118C of the U-shaped tube 118 described later. The fermentation liquid 20 is stored.

The liquid surface 20A is lowered and the liquid surface 20B is raised from the state where the liquid surface 20A and the liquid surface 20B are balanced to the state where the siphon effect described later is obtained. That is, since the fermented liquid 20 is placed in the fermenter 130 to a position that is always higher than the upper end 116A of the partition wall 116, the liquid surfaces 20B of the fermented liquid 20 in the chambers 132 to 134 among the chambers 131 to 134 are mutually different. Will be equal.

Further, inside the chamber 131, a space above the liquid surface 20A of the fermentation liquid 20 is sealed, and biogas generated in the chamber 131 is a sealed space above the liquid surface 20A of the fermentation liquid 20. Accumulate in. Therefore, when the amount of biogas increases and the liquid surface 20A of the fermentation liquid 20 in the chamber 131 is pushed down, the fermentation liquid 20 moves from the chamber 131 to the chambers 132 to 134 via the slit 115C.

Thereby, the difference between the liquid surface 20A of the fermented liquid 20 in the chamber 131 and the liquid surface 20B of the fermented liquid 20 in the chambers 132 to 134 becomes large.

The U-tube 118 is a U-shaped tubular member having ends 118A and 118B and an intermediate portion 118C. The U-shaped pipe 118 is a pipe-shaped member that internally communicates from the end portion 118A to the end portion 118B.

The middle portion 118C of the U-shaped tube 118 is inserted into the through hole 115B of the partition wall 115. The outer peripheral surface of the intermediate portion 118C and the through hole 115B are sealed. Here, to seal between the outer peripheral surface of the intermediate portion 118C and the through hole 115B means to seal between the through hole 115B and the intermediate portion 118C so that the fermentation liquid 20 cannot pass through.

For example, when the U-shaped tube 118 is made of resin, the outer peripheral surface of the intermediate portion 118C and the through hole 115B may be sealed by adhering the outer peripheral surface of the intermediate portion 118C to the through hole 115B. Further, for example, when the U-shaped pipe 118 is made of metal, the outer peripheral surface of the intermediate portion 118C and the through hole 115B may be sealed by welding or bonding the outer peripheral surface of the intermediate portion 118C to the through hole 115B.

The ends 118A and 118B of the U-shaped tube 118 are bent upward on the Z axis on both sides of the intermediate portion 118C and extend to a position of a predetermined height. Here, as an example, the heights of the ends 118A and 118B are equal.

The U-shaped tube 118 is provided to cause a siphon effect between the chamber 131 and the chamber 132. When the difference between the liquid level 20A of the fermented liquor 20 in the chamber 131 and the liquid level 20B of the fermented liquor 20 in the chamber 132 increases to some extent as biogas is generated, the siphon effect using the U-shaped tube 118 is obtained.

When the siphon effect occurs, the fermented liquid 20 moves from the chambers 132 to 134 to the chamber 131. The movement of the fermented liquor 20 is used to stir the fermented liquor 20 in the fermenter 130 and supply the substrate 10 from the pretreatment tank 120 to the fermenter 130 without power through the slit 114B. The specific operation will be described later with reference to FIGS. 3 and 4.

The height of the intermediate portion 118C of the U-shaped tube 118 is determined by the size (volume) of the fermenter 130, the size (volume) of each of the chambers 131 to 134, the size of the slits 115C and 117C, and the height of the partition wall 116. Considering this, it may be adjusted to the liquid level 20A of the fermented liquid 20 in the chamber 131, which is considered to be optimum when producing the siphon effect.

Since the height of the intermediate portion 118C is determined by the height of the through hole 115B of the partition wall 115, the height of the through hole 115B of the partition wall 115 is the height of the fermented liquid 20 in the chamber 131 which is considered to be optimal when producing the siphon effect. It may be adjusted to the liquid surface 20A.

Note that, here, as an example, a case will be described in which the heights of the end portions 118A and 118B are equal, but the heights of the end portions 118A and 118B may not be equal. In particular, the fermented liquor 20 ejected from the end portion 118B into the chamber 132 has an effect of destroying scum (a layer such as oil or sludge contained in the fermented liquor 20) accumulated near the liquid surface 20A of the fermented liquor 20 in the chamber 132. There is. In addition, if the fermented liquid 20 ejected from the end portion 118B bounces off against the baffle plate 119A, the fermented liquid 20 can be sprayed over a wider area, so that the action of destroying the scum becomes greater. Therefore, the height of the end portion 118B may be set to the same height as the end portion 118A from the same height as the middle portion 118C, and the same height as the end portion 118A is most preferable.

The baffle plate 119A guides the fermented liquid 20 flowing from the lower side to the upper side of the chamber 132 in the positive direction of the X-axis, and passes the fermented liquid 20 flowing from the chamber 133 into the chamber 132 through the upper side of the partition 116 in the Z-axis. It is provided for guiding in the negative direction. The angle θ2 of the baffle plate 119A with respect to the Z axis is preferably, for example, 30 degrees to 60 degrees, and most preferably 45 degrees. The angle θ2 of the baffle plate 119A with respect to the Z axis may be set to an optimum angle so that the fermented liquid 20 ejected from the end portion 118B can be sprayed in a wider range.

Next, a process of producing biogas in the biogas generator 100 will be described with reference to FIGS. 3 and 4.

FIG. 3 and FIG. 4 are diagrams showing steps of the biogas generation device 100 generating biogas step by step.

Immediately before the start of the biogas production step, as shown in FIG. 3A, the liquid level 20A of the fermented liquid 20 in the chamber 131 is substantially equal to the height of the end 118A of the U-shaped tube 118. The state shown in FIG. 3(A) is the same as the state shown in FIG. 1, and as an example, the heights of the liquid surface 20B and the liquid surface 20A are equal, and in this state, the fermentation liquid 20 inside the chamber 131, It is assumed that the fermentation liquid 20 in the chambers 132 to 134 is balanced.

In the state shown in FIG. 3A, the fermented liquid 20 in the chambers 131 to 134 begins to generate biogas, and biogas starts to be stored in the upper part of the chamber 131. As a result, the amount of biogas stored in the sealed space above the liquid surface 20A of the fermentation liquid 20 in the chamber 131 gradually increases. Further, with the generation of biogas, the spaces above the liquid surface 20B of the chambers 132 to 134 are in an anaerobic state in which oxygen does not exist. The biogas generated in the chambers 132 to 134 is discharged from the discharge port 113A.

When the amount of biogas increases in the upper part of the chamber 131, the liquid surface 20A of the fermented liquid 20 in the chamber 131 is gradually pushed down as shown in FIG. Through, to the chamber 132 as indicated by arrow B1.

Further, since the chambers 132 and 133 are in communication with each other at the upper part of the partition wall 116 and the chambers 133 and 134 are in communication with each other at the bottom part via the slit 117C, the fermented liquid 20 is as shown by arrows B2 and B3. , From chamber 132 into chambers 133 and 134.

As a result, as shown in FIG. 3B, the liquid surface 20B of the fermented liquid 20 in the chambers 132, 133, and 134 is pushed up.

As described above, when the fermented liquid 20 in the fermenter 130 produces biogas and the liquid surface 20A of the fermented liquid 20 in the chamber 131 is pushed down, the fermented liquid 20 moves from the chamber 131 toward the chamber 134.

When biogas is further generated inside the fermenter 130 and the liquid surface 20A of the fermented liquid 20 in the chamber 131 is pushed down to the bottom of the middle portion 118C of the U-shaped tube 118 as shown in FIG. A siphon effect occurs through the character tube 118.

FIG. 4A shows a state immediately before the siphon effect occurs. As shown by arrows C1, C2, and C3, the fermented liquor 20 flows from the chamber 131 toward the chamber 134.

The siphon effect occurs when the liquid surface 20A of the fermentation liquid 20 in the chamber 131 is pushed down to the bottom of the middle portion 118C of the U-shaped tube 118.

When the siphon effect occurs, as shown in FIG. 4B, the biogas stored in the upper part of the chamber 131 escapes into the chamber 132 through the U-shaped tube 118. At this time, the fermented liquor 20 in the chambers 132 to 134 flows in the direction toward the chamber 131 as shown by the arrows D2 and D3, and returns from the chamber 132 to the chamber 131 via the slit 115C as shown by the arrow D1. come. The change from the state of FIG. 4A to the state of FIG. 4B is completed in about several seconds.

At this time, the water flow (arrow D1) of the fermented liquid 20 that suddenly returns from the chamber 132 to the chamber 131 via the slit 115C passes in front of the slit 114B (X axis positive direction side) and rises inside the chamber 131. To do.

Therefore, the water pressure in the space in front of the slit 114B (on the positive side in the X-axis direction) becomes lower than the water pressure in other portions. That is, the state is such that negative pressure is generated.

Therefore, the substrate 10 containing a large amount of the biomass raw material that precipitates at the bottom of the pretreatment tank 120 flows out into the chamber 131 via the slit 114B.

Further, since the change from the state of FIG. 4(A) to the state of FIG. 4(B) is completed in about several seconds, the water flows represented by the arrows D1 to D3 are water flows that are rapidly generated, and the water flow shown in FIG. 4) and arrows B1 to B3 and arrows C1 to C3 in FIG. 4A.

Further, inside the chambers 132, 133, and 134, as shown by broken line arrows E1, E2, and E3, a swirling water flow is also generated by a rapid water flow.

Therefore, the fermented liquor 20 in the chambers 131 to 134 is wholly agitated by the water flows represented by the arrows D1 to D3 and the water flows that swirl as shown by the dashed arrows E1, E2, and E3. As a result, the concentration of the fermented liquor 20 in the chambers 131 to 134 (concentration of the biomass raw material) is equalized.

From the state shown in FIG. 4(B), until the liquid surface 20A of the fermented liquid 20 in the chamber 131 and the liquid surface 20B of the fermented liquid 20 in the chambers 132 to 134 are in balance, the chamber 132 moves from the chamber 132 to the chamber 131 via the slit 115C. The liquid level 20A of the fermented liquid 20 inside the chamber 131 rises while the fermented liquid 20 moves and the substrate 10 is replenished inside the chamber 131. Further, the fermented liquor 20 in the chambers 131 to 134 is stirred as a whole to equalize the concentration of the fermented liquor 20 (the concentration of the biomass raw material).

Then, when the liquid surface 20A of the fermented liquid 20 in the chamber 131 and the liquid surface 20B of the fermented liquid 20 in the chambers 132 to 134 are balanced, the state shown in FIG. 3(A) is restored.

Then, in the state shown in FIG. 3(A), the fermented liquid 20 in the chambers 131 to 134 produces biogas, and thereafter, as described above, in FIG. 3(B), FIG. 4(A), and FIG. 4(B). The state shown in () is repeated.

In this way, the biogas generator 100 continues to generate biogas. The biogas is discharged from the discharge port 113A to the outside of the biogas generator 100. Further, when the substrate 10 containing a large amount of the biomass raw material that precipitates at the bottom of the pretreatment tank 120 flows out into the chamber 131 through the slit 114B, the same amount as the substrate 10 supplied from the pretreatment tank 120 to the fermentation tank 130. The fermented liquor 20 is discharged from the discharge port 112F and further discharged to a drainage facility or the like (not shown).

As described above, according to the biogas generator 100, the biogas stored in the upper portion of the chamber 131 of the siphon-type fermenter 130 can be used to stir the fermented liquid 20 in the fermenter 130 without power, and The substrate 10 can be supplied to the fermenter from the pretreatment tank 120 by power.

Next, the merits of the biogas generator 100 will be described with reference to FIGS. 5 and 6.

FIG. 5 is a diagram showing a general methane fermentation system 500. Here, first, the general methane fermentation system 500 will be described, and then, the merits of applying the biogas generator 100 to the general methane fermentation system 500 will be described.

As an example, the methane fermentation system 500 is provided in a facility such as a plant, and uses a biomass raw material to generate biogas.

The methane fermentation system 500 includes a crusher 501, a raw material charging pump 502, a pretreatment tank 503, a pretreatment tank stirring pump 504, a substrate charging pump 505, a fermentation tank 506, a fermentation tank stirring pump 507, a hot water circulation pump 508, and a stirring blower 509. , A gas storage tank 510, a pressure fan 511, and a drainage pump 512.

A biomass raw material such as a food residue crushed by the crusher 501 is supplied to the pretreatment tank 503 by the raw material feeding pump 502 and diluted with water to generate a slurry (substrate) containing the biomass raw material. The slurry in the pretreatment tank 503 is stirred by the pretreatment tank stirring pump 504.

The biomass raw material precipitated in the pretreatment tank 503 is supplied to the fermentation tank 506 by the substrate feeding pump 505. The fermented liquid stored in the fermenter 506 is agitated by the fermenter agitation pump 507 and a temperature suitable for fermentation by the hot water circulation pump 508 (for example, a temperature in the range of 30° C. to 60° C., as an example, 35 (Or 55 degrees), and is further stirred by a stirring blower 509.

The biogas generated in the fermenter 506 is stored in the gas storage tank 510 and is supplied to the gas engine by the pressurizing fan 511 as an example. Further, the fermentation liquid that is no longer needed in the fermenter 506 is discharged to drainage equipment by the drainage pump 512.

The electric power generated by the gas engine is extracted as recovered electric power, and part of the electric power is consumed as electric power (consumed power) necessary for the methane fermentation system 500, and surplus electric power (excessive electric power) is installed in the methane fermentation system 500. It can be used in a plant, etc.

Note that the power consumption is, for example, the crusher 501 of the methane fermentation system 500, the raw material feeding pump 502, the pretreatment tank stirring pump 504, the substrate charging pump 505, the fermentation tank stirring pump 507, the hot water circulation pump 508, the stirring blower 509, and the addition. Electric power used to drive the pressure fan 511 and the drainage pump 512.

Further, the heat generated by the gas engine is taken out as recovered exhaust heat, part of which is used as heat required for the methane fermentation system 500 (heat consumption), and the surplus heat (surplus heat) is used as the methane fermentation system 500. Can be used in a plant in which is installed.

The heat consumption is, for example, heat used when the fermented liquid is warmed by the hot water circulation pump 508 of the methane fermentation system 500.

Here, if the biogas generator 100 of the embodiment is applied to the methane fermentation system 500 shown in FIG. 5, power consumption can be reduced as follows.

First, in the biogas generator 100, the pretreatment tank 120 and the fermentation tank 130 are integrated with each other and communicated with each other through the slit 114B, and the water flow generated by the siphon effect is used to remove the pretreatment tank 120 from the pretreatment tank 120 through the slit 114B. The substrate 10 is supplied to the fermenter 130.

This means that in the methane fermentation system 500 shown in FIG. 5, the pretreatment tank 503 and the fermentation tank 506 are integrated.

Therefore, if the biogas generator 100 of the embodiment is applied to the methane fermentation system 500 shown in FIG. 5, the substrate injection pump 505 becomes unnecessary.

Further, the biogas generator 100 uses the water flow generated inside the fermenter 130 to stir the fermentation liquid 20. This corresponds to the roles of the fermenter stirring pump 507 and the stirring blower 509 connected to the fermenter 506 in the methane fermentation system 500 shown in FIG.

Therefore, when the biogas generator 100 according to the embodiment is applied to the methane fermentation system 500 shown in FIG. 5, the fermenter stirring pump 507 and the stirring blower 509 are unnecessary.

As described above, when the biogas generator 100 according to the embodiment is applied to the methane fermentation system 500 shown in FIG. 5, the substrate charging pump 505, the fermenter stirring pump 507, and the stirring blower 509 become unnecessary.

Therefore, when the biogas generator 100 is applied to the methane fermentation system 500 as shown in FIG. 5, the energy recovery efficiency can be improved by reducing the power consumption.

FIG. 6 is a diagram showing a power balance. The horizontal axis represents the amount of food residue (t/day). The amount of food residue (t/day) represents the amount of food residue put in the crusher 501 shown in FIG. 5 in tons per day. The vertical axis represents the power ratio obtained by dividing the power consumption by the recovered power amount in percentage (%).

Further, A (marked with a circle) indicates the power ratio by the methane fermentation system 500 shown in FIG. As described above, the methane fermentation system 500 shown in FIG. 5 includes a crusher 501, a raw material charging pump 502, a pretreatment tank stirring pump 504, a substrate charging pump 505, a fermentation tank stirring pump 507, a hot water circulation pump 508, and a stirring blower 509. Electric power is required to operate the pressurizing fan 511 and the drainage pump 512.

B (marker Δ) indicates the power ratio by the system in which the pretreatment tank 503 and the fermentation tank 506 are integrated and the pretreatment tank stirring pump 504 is omitted in the methane fermentation system 500 shown in FIG. That is, the power consumption of the system B is lower than the power consumption of the system A by the amount of the pretreatment tank stirring pump 504 omitted.

C (marker of □) indicates the electric power ratio in the system in which the fermenter 506 is a siphon type and the fermenter stirring pump 507 and the stirring blower 509 are omitted in the methane fermentation system 500 shown in FIG. The pretreatment tank 503 and the fermentation tank 506 are not integrated.

That is, the power consumption of the system C is lower than the power consumption of the system A by the amount that the fermenter stirring pump 507 and the stirring blower 509 are omitted.

D (marker ⋄) saves the substrate injection pump 505, the fermenter stirring pump 507, and the stirring blower 509 by applying the biogas generator 100 of the embodiment to the methane fermentation system 500 shown in FIG. Shows the power ratio due to the existing system.

That is, the power consumption of the system D is lower than the power consumption of the system A by the amount that the substrate charging pump 505, the fermenter stirring pump 507, and the stirring blower 509 are omitted.

As shown in FIG. 6, it can be seen that in any of the systems A to D, the power ratio tends to decrease as the amount of food residue increases. This is because an increase in the amount of food residues improves the energy recovery efficiency.

However, in the systems A and B, even if the amount of food residue is increased to 1 (t/day), the power ratios are 130% and 126%, respectively, and the power consumption exceeds the recovered power amount. I understand. This means that in order to obtain renewable energy from the biomass raw material, more electric power is consumed than the renewable energy that can be recovered, and the power balance is negative.

In the systems C and D, when the amount of food residue is about 0.25 (t/day) or more, the power ratio is about 100% or less.

More specifically, in the systems C and D, the power ratios are 75% and 70%, respectively, when the amount of food residue is 0.3 (t/day). When the amount of food residue is 0.6 (t/day), the power ratios are 57% and 53%, respectively. When the amount of food residue is 1 (t/day), the power ratios are 48% and 44%, respectively.

From the above, it can be seen that the power ratio of the D system is improved by about 5% as compared with the C system.

Therefore, the biogas generator 100 according to the embodiment uses the biogas stored in the upper part of the chamber 131 of the siphon-type fermenter 130 to stir the fermented liquid 20 in the fermenter 130 without power, and to use the power without power. By supplying the substrate 10 from the pretreatment tank 120 to the fermentation tank, the energy recovery efficiency (regeneration efficiency) can be improved.

Therefore, according to the embodiment, it is possible to provide the biogas generator 100 having high energy recovery efficiency.

Further, in the above description, the treatment tank 110 in which the pretreatment tank 120 and the fermentation tank 130 are integrated is used, and the substrate 10 is introduced from the pretreatment tank 120 into the fermentation tank 130 through the slit 114B. However, the treatment tank 110 may be configured not to include the pretreatment tank 120, but to introduce the substrate 10 into the fermentation tank 130 by using, for example, a pump or the like for the substrate 10 stored in a container.

Further, in the above description, in the treatment tank 110 in which the pretreatment tank 120 and the fermentation tank 130 are integrated, the configuration in which the pretreatment tank 120 and the fermentation tank 130 are partitioned by the partition plate 114 has been described. The tank 120 and the fermentation tank 130 may be separated. Instead of the slit 114B, a flow path connecting an opening provided in the lower portion of the pretreatment tank 120 and a raw material inlet provided in the lower portion of the fermentation tank 130 is provided, and the biomass raw material that has settled inside the flow passage is It may be filled.

Moreover, although the form in which the slit 114B is formed between the bottom plate 111 of the pretreatment tank 120, the fermentation tank 130, and the lower end 114A of the partition plate 114 has been described above, the position of the slit 114B is slightly smaller than that of the bottom plate 111. It may be in a high position.

Moreover, although the form which fermenter 130 has four chambers 131-134 was demonstrated above, fermenter 130 does not need to have chamber 134. In this case, the discharge port 112F may be provided in the chamber 133. Further, the fermenter 130 may not have the chambers 133 and 134. In this case, the discharge port 112F may be provided in the chamber 132. Further, the fermentor 130 may have five or more chambers.

Further, the discharge port 113A for discharging the biogas may be attached anywhere in the X-axis direction as long as it is between the partition wall 115 and the partition plate 119B.

Although the biogas generator according to the exemplary embodiment of the present invention has been described above, the present invention is not limited to the specifically disclosed embodiment, and deviates from the scope of the claims. However, various modifications and changes are possible.

10 Substrate 10A Liquid Level 20 Fermentation Liquid 20A, 20B Liquid Level 100 Biogas Generator 110 Processing Tank 111 Bottom Plate 112, 112A, 112B, 112C, 112D Side Wall 112F Discharge Port 113 Top Plate 113A Discharge Port 114 Partition Plate 114B Slit 115, 116 117 Partition wall 115B Through hole 118 U-shaped tube 118A, 118B End part 118C Intermediate part 119A Baffle plate 119B Partition plate 119C Partition board 120 Pretreatment tank 130 Fermentation tank

Claims (4)

A biogas generator including a siphon-type fermenter that stores a fermentation liquid containing a biomass raw material in the presence of microorganisms to generate biogas,
The fermentor is
A raw material inlet provided at the bottom of the fermenter,
An outlet provided in the upper part of the fermentation tank at a position separated from the raw material inlet in a plan view, and an outlet for discharging the biogas,
At a position between the raw material input port and the discharge port in a plan view, it extends from the top plate of the fermentation tank to a first height position before the first predetermined distance of the bottom plate inside the fermentation tank, and penetrates. A first partition having a hole, a space above the through hole is sealed, and a first tank in which the raw material charging port is provided in a lower portion, and a bottom portion of the fermentation tank to be the first tank. A first partition that is in communication with each other and that divides the internal space of the fermentation tank into a second tank in which the discharge port is provided in the upper portion;
It is connected to the lower end of the first height position of the first partition wall, extends obliquely toward the second tank side to a second height position lower than the first height position, and is included in the fermentation liquid. A baffle plate that obstructs the outflow of the solid matter to the second tank side,
A U-shaped tube having a first end and a second end, wherein the U-shaped pipe is inserted into the through hole of the first partition wall at an intermediate portion between the first end and the second end, with respect to the intermediate portion. A U-shaped tube, wherein the first end and the second end extend upward, and a biogas generator. The biogas stored in the upper part of the first tank pushes down the liquid level of the fermented liquid in the first tank, and the fermented liquid in the first tank moves into the second tank to move to the second tank. The liquid level of the fermented liquid in the tank is pushed up,
When the liquid surface of the fermented liquid in the first tank is pushed down to the intermediate portion of the U-shaped tube, due to the siphon effect through the U-shaped tube, the liquid surface of the fermented liquid in the first tank, and The biogas generator according to claim 1, wherein the fermented liquid moves from the second tank to the first tank until the liquid level of the fermented liquid in the second tank is balanced. The biogas generator according to claim 2, wherein the biomass raw material is supplied to the raw material inlet of the first tank when the fermented liquid moves from the second tank to the first tank due to the siphon effect. The biogas generator according to any one of claims 1 to 3, wherein the fermentation tank further includes one or a plurality of second partition walls that divide the second tank into a plurality of tanks.

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