JP6792437B2 - Biogas generator - Google Patents

Description

The present invention relates to a biogas generator.

Conventionally, a receiving portion for receiving the food waste crushing waste liquid is provided, and a solid-liquid separation tank for precipitating and separating the food waste crushing waste liquid is provided, and the liquid phase separated by the solid-liquid separation tank is drained to the outside. The drainage section is provided in the solid-liquid separation tank, and an anaerobic fermentation tank that receives the precipitate separated by the solid-liquid separation tank and biogasifies it is provided. A transfer section for transferring a substance is provided, and the transfer section closes the space between the solid-liquid separation tank and the anaerobic fermentation tank with the precipitate to separate the solid component from the anaerobic fermentation tank. A throttle portion that can prevent backflow to the tank is provided, and the precipitate is transferred to the anaerobic fermentation tank via the throttle portion, and the excess liquid phase of the anaerobic fermentation tank is passed through the throttle portion. The anaerobic fermenter is provided with a sediment transfer mechanism that allows the precipitate to be returned to the solid-liquid separation tank, and the anaerobic fermenter has a wastewater treatment device provided with a biogas take-out path for taking out the generated biogas to the outside (for example). , Patent Document 1).

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

There is also a methane fermentation continuous operation device 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 portion of the first chamber pushes down the liquid level with biogas. When the liquid level in the first chamber reaches the bottom of the U-shaped tube, the biogas stored in the gas phase part of the first chamber moves to the second chamber through the U-shaped tube, and the fermented liquid moves to the first chamber. It is pulled back, the liquid level in the first chamber rises, and the liquid level in the second to fourth chambers falls. The liquid flow generated at this time causes stirring in the fermenter. However, the raw material (simulated kitchen 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, for example, Non-Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-027851

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

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

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

Therefore, it is an object of the present invention to provide a biogas generator having high energy recovery efficiency.

The biogas generator according to the embodiment of the present invention is a pretreatment tank for precipitating biomass raw materials in water, and includes a pretreatment tank having an opening at the bottom, a pipe having one end connected to the opening, and a pipe. A pump provided between the one end and the other end of the pipe to send the biomass raw material from the one end side to the other end side, and a fermentation broth containing the biomass raw material supplied via the pipe are used as microorganisms. A siphon-type fermenter that stores biogas in the presence of the above-mentioned fermenter and a post-treatment device for post-treating the waste water of the fermenter are provided. A raw material input port connected to a pipe, a discharge port provided on the upper part of the fermenter at a position separated from the raw material input port in a plan view, and a discharge port for discharging the biogas, and the raw material input port and the raw material input port in a plan view. A first partition wall extending from the top plate of the fermenter to a first height position in front of the first predetermined distance of the bottom plate inside the fermenter at a position between the discharge port and having a through hole. The space above the through hole is sealed, and the first tank provided with the raw material input port at the lower part and the first tank at the bottom of the fermenter are communicated with the first tank, and the exhaust at the upper part. A U-shaped pipe having a first partition wall that divides the internal space of the fermenter into a second tank provided with an outlet and a first end and a second end, and is between the first end and the second end. is the inserted into the through hole of the first partition wall in the middle portion, the first end and the second end extending upwardly with respect to said intermediate portion, possess a U-shaped tube, the pretreatment tank , Has a solid-liquid separation function, and the supernatant water is supplied to the aftertreatment device under natural flow .

It is possible to provide a biogas generator having high energy recovery efficiency.

It is sectional drawing which shows the 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 which the biogas generator 100 produces biogas step by step. It is a figure which shows the process which the biogas generator 100 produces biogas step by step. It is a figure which shows the modification of the embodiment. It is a figure which shows the general methane fermentation system 500. It is a figure which shows the electric power balance.

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

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

In FIGS. 1 and 2, an XYZ coordinate system, which is a Cartesian coordinate system, is defined as shown in the figure. Here, as an example, the XY plane is a horizontal plane, and the Z-axis positive direction is vertically above. Plane view means viewing the XY plane from the positive direction of the Z axis.

The biogas generator 100 includes a processing tank 110 as a main component. The biogas generator 100 includes, in addition to the treatment tank 110, a device for treating the biogas generated in the treatment layer 110, a device for treating wastewater from the treatment layer 110, and the like, but this is omitted in FIG.

The processing tank 110 includes a bottom plate 111α, 111β, a side wall 112, a top plate 113α, 113β, a partition wall 115, 116, 117, a U-shaped tube 118, a baffle plate 119A, a partition plate 119B, a partition board 119C, a pump 140, and a pipe 141. Have.

Here, in the processing tank 110, the side in the negative direction of the X-axis with respect to the partition plate 114α is referred to as a pretreatment tank 120, and the side in the positive direction of the X-axis with respect to the partition plate 114β is referred to as a fermentation tank 130. The pretreatment tank 120 and the fermentation tank 130 are connected to each other via a pipe 141, and the pipe 141 is provided with a pump 140.

The pretreatment tank 120 is sandwiched between the bottom plate 111α and the top plate 113α in the Z-axis direction, and the fermentation tank 130 is sandwiched between the bottom plate 111β and the top plate 113β in the Z-axis direction. .. Further, the pretreatment tank 120 and the fermentation tank 130 extend between the bottom plates 111α and 111β and the top plates 113α and 113β in the Z-axis direction, respectively.

As shown in FIG. 2, the bottom plates 111α and 111β are rectangular plate-shaped members in a plan view, and are located at the bottom of the processing tank 110. The bottom plates 111α and 111β are the bottoms of the treatment tank 110.

The side wall 112 has side walls 112A, 112Bα, 112Bβ, 112C, 112Dα, 112Dβ, and 112Gα, 112Gβ (see FIG. 2). The side walls 112A, 112Bα, 112Dα, and 112Gα are arranged in a rectangular ring shape in a plan view along the four sides of the bottom plate 111α. The side walls 112Bβ, 112C, 112Dβ, and 112Gβ are arranged in a rectangular annular shape in this order along the four sides of the bottom plates 111α and 111β.

The side walls 112A, 112Bα, 112Bβ, 112C, 112Dα, 112Dβ, and 112Gα and 112Gβ are rectangular plate-shaped members, respectively, and surround the side surface of the treatment tank 110. The side wall 112A is provided with an inflow port 112E for allowing the slurry containing the biomass raw material to flow into the treatment tank 110. The inflow port 112E is provided at a position close to the top plate 113α in the Z-axis direction.

Further, the side wall 112C is provided with a discharge port 112F for discharging the liquid. The discharge port 112F is provided at a position close to the top plate 113β in the Z-axis direction. Further, openings 112Hα and 112Hβ are provided at the bottoms of the side walls 112Gα and 112Gβ, respectively, and the openings 112Hα and 112Hβ are connected by a pipe 141. That is, the pretreatment tank 120 and the fermentation tank 130 are communicated with each other by a pipe 141.

In the following, when the side walls 112A, 112Bα, 112Bβ, 112C, 112Dα, 112Dβ, and 112Gα, 112Gβ are not particularly distinguished, they are simply referred to as the side wall 112.

The top plates 113α and 113β are rectangular plate-shaped members in a plan view, and are provided on the upper surface of the processing tank 110. Here, as an example, it is assumed that the sizes of the top plates 113α and 113β in a plan view are equal to the bottom plates 111α and 111β, respectively. The top plate 113β is provided with a discharge port 113A for discharging biogas.

When the bottom plates 111α, 111β, side walls 112, and top plates 113α, 113β are made of metal, they may be fixed by welding, screwing, or the like. When the bottom plates 111α and 111β, the side wall 112, and the top plates 113α and 113β are made of resin, they may be fixed by adhesion or screwing. Further, the surfaces of the bottom plates 111α and 111β, the side walls 112, and the top plates 113α and 113β may be coated or antiseptic treated as necessary.

The partition walls 115, 116, 117, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C are arranged in the internal space constructed by the bottom plates 111α, 111β, the side wall 112, and the top plates 113α, 113β. To. The partition walls 115, 116, 117, the U-shaped tube 118, the baffle plate 119A, the partition plate 119B, and the partition board 119C are made of, for example, metal or resin.

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

The pump 140 is provided in a pipe 141 connecting between the openings 112Hα and 112Hβ. The pump 140 is, for example, a pneumatic pump. When the pump 140 is driven, the substrate 10 is supplied from the pretreatment tank 120 to the fermentation tank 130 via the pipe 141. The pump 140 is driven only when the slurry containing the biomass raw material is delivered to the fermenter 130, for example, every 10 minutes for 30 seconds. The opening 112Hβ is an example of a raw material input port provided in the lower part of the fermentation tank 130.

The pretreatment tank 120 may be regarded as an adjustment tank or a solid-liquid separation tank. Further, the fermentation tank 130 may be regarded as an anaerobic fermentation tank.

The pretreatment tank 120 is a tank that stores a slurry containing a biomass raw material and performs a pretreatment for precipitating the biomass raw material. Since there are no microorganisms inside the pretreatment tank 120, biogas is not generated.

A slurry containing a biomass raw material is a liquid obtained by mixing a biomass raw material with water and is referred to as a substrate. FIG. 1 shows a dark dot pattern as the substrate 10. 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. When the pump 140 is driven, the substrate 10 is supplied to the fermenter 130 from the opening 112Hα of the pretreatment tank 120 via the pipe 141 and the opening 112Hβ, and becomes the fermented liquid 20 inside the fermenter 130. FIG. 1 shows the fermentation broth 20 in a thin dot pattern. Microorganisms that decompose biomass raw materials are mixed in the fermentation broth 20.

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

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

The fermenter 130 is supplied with microorganisms under anaerobic conditions and uses the substrate 10 supplied from the pretreatment tank 120 via the opening 112Hα, the pipe 141, and the opening 112Hβ to generate biogas. It is a tank. The fermenter 130 has a siphon type structure.

Further, although not shown in FIG. 1 because only the main components are shown, a hot water circulation pump is connected to the fermenter 130. The fermentation broth 20 is held by a hot water circulation pump 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).

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

Here, it will be described that the internal space of the fermenter 130 is divided into four chambers 131, 132, 133, and 134 by three partition walls 115, 116, and 117. The four chambers 131, 132, 133, and 134 communicate with each other.

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

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

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

The three sides of the partition wall 115 other than the lower end 115A are fixed to the side walls 112Bβ and 112Dβ and the top plate 113β.

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 (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 configuration partitions the internal space of the fermenter 130 into a negative X-axis side and a positive X-axis side at a position higher than the height h2 from the bottom plate 111β. Further, the partition wall 115 has a slit 115C having a height of h2 constructed at the bottom of the internal space of the fermenter 130. The slit 115C has a height of h2 and is provided between the side wall 112Bβ and the side wall 112Dβ.

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

Further, above the lower end 115A of the partition wall 115 in the chamber 131, the side wall 112Gβ, the top plate 113β, the partition wall 115, and the fermented liquid 20 are provided, except that the U-shaped tube 118 communicates with the chamber 132. It is configured to create a space sealed by the liquid level 20A.

The chamber 131 communicates with the pretreatment tank 120 by a pipe 141, 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 a space sealed by the upper side wall 112Gβ of the chamber 131, the top plate 113β, the partition wall 115, and the liquid level 20A of the fermentation broth 20.

Further, in the chamber 132, the substrate 10 is supplied from the chamber 131 to generate biogas. The biogas produced in the chamber 132 is discharged from the discharge port 113A through the space above the liquid level 20B of the fermentation liquid 20 in the chambers 132 to 134.

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

The partition wall 116 extends from the bottom plate 111β to a position at a height h3 in the Z-axis direction. Further, the partition wall 116 extends from the side wall 112Bβ to the side wall 112Dβ in the Y-axis direction. The upper end 116A of the partition wall 116 is located at a height h3 from the bottom plate 111β in the Y-axis direction between the side wall 112Bβ and the side wall 112Dβ.

The three sides of the partition wall 116 other than the upper end 116A are fixed to the side walls 112Bβ and 112Dβ and the bottom plate 111β.

The partition wall 116 having such a configuration divides the internal space of the fermenter 130 into a negative X-axis side and a positive X-axis side at a position lower than the height h3 from the bottom plate 111β.

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

In the chamber 133, the substrate 10 is supplied through the chamber 132 to generate biogas. The biogas produced 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 arranged in parallel with the YZ plane inside the processing tank 110. The partition wall 117 is an example of the second partition wall. The partition wall 117 extends from a position at a height h2 from the bottom plate 111β to a position lowered by a height h4 from the top plate 113β in the Z-axis direction.

Further, the partition wall 117 extends from the side wall 112Bβ to the side wall 112Dβ in the Y-axis direction. The lower end 117A of the partition wall 117 is located at a height h2 from the bottom plate 111β in the Y-axis direction between the side wall 112Bβ and the side wall 112Dβ. The upper end 117B of the partition wall 117 is located between the side wall 112Bβ and the side wall 112Dβ by a height h4 below the top plate 113β in the Y-axis direction.

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

The partition wall 117 having such a configuration sets the internal space of the fermenter 130 on the negative side of the X-axis and the X-axis at a position higher than the bottom plate 111β at a height h2 and lower than the top plate 113β by a height h4. It is separated from the positive side.

Further, the partition wall 117 has a slit 117C having a height of h2 constructed at the bottom of the internal space of the fermenter 130. The slit 117C has a height of h2 and is provided between the side wall 112Bβ and the side wall 112Dβ. Further, the partition wall 117 has a slit 117D having a height of h4 constructed in the upper part of the internal space of the fermenter 130. The slit 117D has a height of h4 and is provided between the side wall 112Bβ and the side wall 112Dβ.

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 chamber 133, and the X-axis positive direction side of the partition wall 117 is referred to as chamber 134. The chamber 133 and the chamber 134 extend between the bottom plate 111β and the top plate 113β in the Z-axis direction, and the chamber 133 and the chamber 134 are provided by slits 117C and 117D located above and below the partition wall 117, respectively. It is communicated.

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 broth 20 to the discharge port 112F.

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

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 112Bβ to the side wall 112Dβ in the Y-axis direction, and is viewed from the negative Y-axis side to the positive Y-axis side in the XZ plane with respect to the positive Z-axis direction. It is angled so that it forms 135 degrees in the clockwise direction.

The size of the partition plate 119B constructed by such plates 119B1 and 119B2 is set so that the lower end is immersed in the fermentation broth 20.

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

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

In 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 in the internal space of the chamber 134. It may be different from the liquid level 20B outside the space where it is used.

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

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

The state shown in FIG. 1 is a state in which 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, the liquid levels 20A and 20B are higher than the partition wall 116 and the intermediate portion 118C of the U-shaped tube 118, which will be described later, in a state where the liquid level 20A and the liquid level 20B are balanced. The fermented liquid 20 is stored.

The liquid level 20A decreases and the liquid level 20B rises from the state in which the liquid level 20A and the liquid level 20B are balanced to the state in which the siphon effect described later is obtained. That is, since the fermented liquid 20 is always placed in the fermenter 130 to a position higher than the upper end 116A of the partition wall 116, the liquid levels 20B of the fermented liquid 20 in the chambers 132 to 134 of the chambers 131 to 134 are mutually exclusive. Become equal.

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

As a result, the difference between the liquid level 20A of the fermented liquid 20 in the chamber 131 and the liquid level 20B of the fermented liquid 20 in the chambers 132 to 134 becomes large.

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

The intermediate portion 118C of the U-shaped tube 118 is inserted through 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, sealing between the outer peripheral surface of the intermediate portion 118C and the through hole 115B means sealing between the through hole 115B and the intermediate portion 118C so that the fermented 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 tube 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 adhering 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 predetermined height position. Here, as an example, the heights of the ends 118A and 118B are equal.

The U-shaped tube 118 is provided to generate a siphon effect between the chamber 131 and the chamber 132. When the difference between the liquid level 20A of the fermented liquid 20 of the chamber 131 and the liquid level 20B of the fermented liquid 20 of the chamber 132 increases to some extent with the generation of biogas, a siphon effect using the U-shaped tube 118 can be obtained.

When the siphon effect occurs, the fermented liquid 20 moves from the chambers 132 to 134 to the chamber 131. Utilizing such movement of the fermented liquid 20, the fermented liquid 20 in the fermenter 130 is agitated, and the substrate 10 is supplied from the pretreatment tank 120 to the fermenter 130 by the driving force of the pump 140 via the pipe 141. .. The specific operation will be described later with reference to FIGS. 3 and 4.

The height of the middle portion 118C of the U-shaped tube 118 is the size (capacity) of the fermenter 130, the respective sizes (capacity) of the chambers 131 to 134, the sizes of the slits 115C and 117C, the height of the partition wall 116, and the like. In consideration, the liquid level 20A of the fermented liquid 20 of the chamber 131, which is considered to be optimal for producing the siphon effect, may be adjusted.

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 considered to be optimal for producing the siphon effect of the fermented liquid 20 of the chamber 131. It may be adjusted to the liquid level 20A.

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 guides the fermented liquid 20 flowing from the chamber 133 to the chamber 132 through the upper side of the partition wall 116 on the Z-axis. It is provided to guide in the negative direction.

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

3 and 4 are diagrams showing the steps of the biogas generator 100 to generate biogas stepwise.

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

In the state shown in FIG. 3A, the fermentation broth 20 of the chambers 131 to 134 begins to generate biogas, and the biogas begins to accumulate in the upper part of the chamber 131. As a result, the amount of biogas stored in the sealed space above the liquid level 20A of the fermentation liquid 20 in the chamber 131 gradually increases. Further, with the generation of biogas, the space above the liquid level 20B of the chambers 132 to 134 becomes anaerobic in the absence of oxygen. The biogas produced 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, as shown in FIG. 3B, the liquid level 20A of the fermented liquid 20 of the chamber 131 is gradually pushed down, and the fermented liquid 20 of the chamber 131 passes through the slit 115C. Via, move to chamber 132 as indicated by arrow B1.

Further, since the chambers 132 and 133 communicate with each other at the upper part of the partition wall 116 and the chambers 133 and 134 communicate with each other at the bottom through the slit 117C, the fermented liquid 20 is indicated by arrows B2 and B3. , Flow from chamber 132 into chambers 133 and 134.

As a result, as shown in FIG. 3B, the liquid level 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 level 20A of the fermented liquid 20 in the chamber 131 is pushed down, the fermented liquid 20 moves from the chamber 131 to 134.

Further biogas is generated inside the fermenter 130, and as shown in FIG. 4 (A), when the liquid level 20A of the fermented liquid 20 in the chamber 131 is pushed down to the bottom of the intermediate portion 118C of the U-shaped tube 118, the U A siphon effect is produced through the letter tube 118.

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

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

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

At this time, the water flow (arrow D1) of the fermented liquid 20 that rapidly returns from the chamber 132 to the chamber 131 through the slit 115C passes in front of the opening 112Hβ (on the positive direction side of the X-axis) and passes through the inside of the chamber 131. Rise.

Therefore, the water pressure in the space in front of the opening 112Hβ (in front of the positive direction side of the X-axis) is lower than the water pressure in other parts. That is, it becomes a state in which a negative pressure is generated.

Therefore, the substrate 10 containing a large amount of biomass raw material that precipitates at the bottom of the pretreatment tank 120 flows out into the chamber 131 through the opening 112Hβ.

Further, since the change from the state of FIG. 4 (A) to the state of FIG. 4 (B) is completed in about a few seconds, the water flows represented by arrows D1 to D3 are suddenly generated water flows, and are shown in FIG. 3 (B). ) And the water flow represented by arrows B1 to B3 and arrows C1 to C3 in FIG. 4 (A).

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

Therefore, the fermented liquid 20 in the chambers 131 to 134 is totally agitated by the water flow represented by the arrows D1 to D3 and the swirling water flow indicated by the dashed arrows E1, E2, and E3. As a result, the concentration of the fermentation broth 20 (concentration of the biomass raw material) in the chambers 131 to 134 is equalized.

From the state shown in FIG. 4B, from the chamber 132 to the chamber 131 via the slit 115C until the liquid level 20A of the fermented liquid 20 of the chamber 131 and the liquid level 20B of the fermented liquid 20 of the chambers 132 to 134 are balanced. 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 fermentation broth 20 of the chambers 131 to 134 is generally stirred to equalize the concentration of the fermentation broth 20 (concentration of the biomass raw material).

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

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

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

As described above, according to the biogas generator 100, the fermented liquid 20 of the fermenter 130 can be agitated by the driving force of the pump 140 by using the biogas stored in the upper part of the chamber 131 of the siphon type fermenter 130. At the same time, the substrate 10 can be supplied from the pretreatment tank 120 to the fermentation tank by the driving force of the pump 140.

FIG. 5 is a diagram showing a modified example of the embodiment. The biogas generator 100 shown in FIG. 5A includes a pretreatment tank (storage tank) 120, a fermentation tank 130, and a posttreatment device 150 in addition to the pump 140. For example, when the pretreatment tank (storage tank) 120 has a solid-liquid separation function, the supernatant water of the pretreatment tank (storage tank) 120 may be supplied to the post-treatment apparatus 150 through a pipe 151 under a natural flow. Natural flow means that the liquid is sent from a high place to a low place by the flow generated by gravity without using the power of a pump or the like.

Further, the fermentation tank 130 may be used for medium temperature fermentation (for example, 35 ° C.) or high temperature fermentation (for example, 55 ° C.).

Further, as shown in FIG. 5B, the biogas generator 100 includes a pretreatment tank (storage tank) 120, a fermentation tank 130, and a posttreatment device 150A in addition to the pump 140, and the posttreatment device 150A , It may be an aerobic treatment tank that performs aerobic treatment. Then, the residue 21 accumulated in the aftertreatment device 150A may be returned to the pretreatment tank (storage tank) 120 by a pump.

Further, as shown in FIG. 5C, the biogas generator 100 includes a UASB tank 150B for methane fermentation with granulated methanogens and a UASB (Upflow Anaerobic Sludge Blanket; upward-flowing anaerobic sludge). It may be configured to include an aerobic treatment tank 150A for aerobically treating the effluent from the floor) tank. The UASB tank is a tank using a methane fermentation method (anaerobic treatment method) in high-concentration organic wastewater treatment. The bubbling blower used in the aftertreatment device 150A may also be used as the pump 140.

Further, the pump for returning the residue 21 to the pretreatment tank (storage tank) 120 may be a combination of a bubbling blower 141A and an air lift pump 142A as in the pump 140A shown in FIG. 5 (D). ..

Next, the merits of the biogas generator 100 will be described with reference to FIGS. 6 and 7.

FIG. 6 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 installed 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 input pump 502, a pretreatment tank 503, a pretreatment tank stirring pump 504, a substrate charging pump 505, a fermenting tank 506, a fermenting tank stirring pump 507, a hot water circulation pump 508, and a stirring blower 509. , Gas storage tank 510, pressurizing fan 511, and drainage pump 512.

Biomass raw materials such as food residues crushed by the crusher 501 are supplied to the pretreatment tank 503 by the raw material input pump 502 and diluted with water to generate a slurry (substrate) containing the biomass raw materials. The slurry in the pretreatment tank 503 is agitated 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 input pump 505. The fermented liquid stored in the fermenter 506 is agitated by the fermenter agitation pump 507 and is 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, for example, 35. It is held at a degree (or 55 degrees) and is further stirred by a stirring blower 509.

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

The electric power generated by the gas engine is taken out as recovered electric power, and a part of the electric power is consumed as the electric power (power consumption) required for the methane fermentation system 500, and the surplus electric power (surplus electric power) is installed in the methane fermentation system 500. It can be used in various plants.

The power consumption is, for example, the crusher 501 of the methane fermentation system 500, the raw material input 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. This is the 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, and a part of it is used as heat (heat consumption) required for the methane fermentation system 500, and the excess heat (surplus heat) is used in the methane fermentation system 500. Can be used in plants where is installed.

The heat consumption is, for example, the heat used when warming the fermentation broth with 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. 6, the power consumption can be reduced as follows.

First, the biogas generator 100 integrates the pretreatment tank 120 and the fermentation tank 130 and communicates them with the pipe 141, and utilizes the water flow generated by the siphon effect from the pretreatment tank 120 via the pipe 141. The substrate 10 is supplied to the fermenter 130.

This means that in the methane fermentation system 500 shown in FIG. 6, 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. 6, the substrate input pump 505 becomes unnecessary.

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

Therefore, if the biogas generator 100 of the embodiment is applied to the methane fermentation system 500 shown in FIG. 6, the fermentation tank stirring pump 507 and the stirring blower 509 become unnecessary.

As described above, when the biogas generator 100 of the embodiment is applied to the methane fermentation system 500 shown in FIG. 6, the substrate input 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. 6, the energy recovery efficiency can be improved by reducing the power consumption.

FIG. 7 is a diagram showing a power balance. The horizontal axis indicates the amount of food residue (t / day). The amount of food residue (t / day) represents the amount of food residue charged into the crusher 501 shown in FIG. 6 in tonnage per day. The vertical axis represents the power ratio obtained by dividing the power consumption by the amount of recovered power as a percentage (%).

Further, A (marker of ◯) indicates the power ratio by the methane fermentation system 500 shown in FIG. As described above, the methane fermentation system 500 shown in FIG. 6 includes a crusher 501, a raw material input pump 502, a pretreatment tank stirring pump 504, a substrate charging pump 505, a fermenter stirring pump 507, a hot water circulation pump 508, and a stirring blower 509. , Pressurization fan 511, and drainage pump 512 require electric power to operate.

B (marker of Δ) indicates the power ratio by the system in which the pretreatment tank 503 and the fermenter 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 omitting the pretreatment tank stirring pump 504.

C (marker of □) indicates the power ratio by 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 of omitting the fermenter stirring pump 507 and the stirring blower 509.

D (marker of ◇) saves the substrate input 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 of the existing system.

That is, the power consumption of the system D is less than the power consumption of the system A by the amount of omitting the substrate input pump 505, the fermenter stirring pump 507, and the stirring blower 509.

As shown in FIG. 7, in any of the systems A to D, it can be seen that the power ratio tends to decrease as the amount of food residue increases. This is because the energy recovery efficiency is improved by increasing the amount of food residue.

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 biomass raw materials, more electricity is consumed than recoverable renewable energy, and the electricity balance is negative.

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

More specifically, in the C and D systems, 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. Further, 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 system D is improved by about 5% as compared with the system C.

Therefore, the biogas generator 100 of 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 of the fermenter 130 with the driving force of the pump 140. By supplying the substrate 10 from the pretreatment tank 120 to the fermentation tank by the driving force of the pump 140, 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, although the form in which the fermenter 130 has four chambers 131 to 134 has been described above, the fermenter 130 may not have the chamber 134. In this case, the discharge port 112F may be provided in the chamber 133. Further, the fermenter 130 does not have to have chambers 133 and 134. In this case, the discharge port 112F may be provided in the chamber 132. Further, the fermentation tank 130 may have five or more chambers.

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

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 embodiments and deviates from the scope of claims. It is possible to make various modifications and changes.

10 Substrate 10A Liquid level 20 Fermentation liquid 20A, 20B Liquid level 100 Biogas generator 110 Treatment tank 111 Bottom plate 112, 112A, 112Bα, 112Bβ, 112C, 112Dα, 112Dβ, 112Gα, 112Gβ Side wall 112F Outlet 112Hα, 112Hβ Opening 113 Top plate 113A Discharge port 115, 116, 117 Partition wall 115B Through hole 118 U-shaped tube 118A, 118B End 118C Intermediate part 119A Interfering plate 119B Partition plate 119C Partition board 120 Pretreatment tank 130 Fermentation tank

Claims (5)

A pretreatment tank for precipitating biomass raw materials in water, with a pretreatment tank having an opening at the bottom,
A pipe whose one end is connected to the opening
A pump provided between the one end and the other end of the pipe and delivering the biomass raw material from the one end side to the other end side.
A siphon-type fermenter that produces biogas by storing the fermented liquid containing the biomass raw material supplied via the pipe in the presence of microorganisms .
Including a post-treatment device for post-treating the wastewater from the fermenter
The fermenter
A raw material input port provided at the bottom of the fermenter and connected to the pipe,
A discharge port provided on the upper part of the fermenter at a position separated from the raw material input port in a plan view and discharging the biogas.
At a position between the raw material input port and the discharge port in a plan view, the inside of the fermenter extends from the top plate of the fermenter to the first height position before the first predetermined distance of the bottom plate and penetrates. A first partition wall having a hole, the space above the through hole is sealed, and the first tank is provided with the raw material input port at the bottom, and the first tank is at the bottom of the fermenter. A first partition wall that divides the internal space of the fermenter into a second tank that is communicated and has the discharge port at the top.
A U-shaped tube having a first end and a second end, which 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. It said first end and said second end extending upward, possess a U-shaped tube,
The pretreatment tank has a solid-liquid separation function, and a biogas generator in which supernatant water is supplied to the post-treatment device under natural flow . 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 the second tank. The level of the fermented liquid in the tank is pushed up,
When the liquid level of the fermented liquid in the first tank is pushed down to the intermediate portion of the U-shaped tube, the liquid level of the fermented liquid in the first tank and the liquid level of the fermented liquid in the first tank are caused by the siphon effect through the U-shaped tube. 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. A claim that when the fermentation broth moves from the second tank to the first tank due to the siphon effect, the biomass raw material is supplied from the opening of the pretreatment tank to the raw material inlet of the first tank. Item 2. The biogas generator according to item 2. The biogas generator according to any one of claims 1 to 3, wherein the fermentation tank further has one or a plurality of second partition walls that divide the second tank into a plurality of tanks. The biogas generation according to any one of claims 1 to 4 , wherein the post-treatment device is a post-treatment device that performs an aerobic treatment, and the residue generated by the post-treatment device is supplied to the pre-treatment tank. apparatus.

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