Methane fermentation device and methane fermentation method

Abstract

To achieve reduction of cost and simplification of a device configuration with an advantage in maintenance-management, and put a temperature of a methane fermentation liquid in a methane fermentation tank in an appropriate temperature range.SOLUTION: A methane fermentation device includes: a methane fermentation tank 2 for subjecting organic waste B to methane fermentation treatment; and a plurality of partition bodies 4 for partitioning the methane fermentation tank 2 into a plurality of treatment regions 3. The methane fermentation tank 2 is configured to supply a methane fermentation liquid C containing the organic waste B charged into the methane fermentation tank 2 to the plurality of treatment regions 3 in a form of sequentially moving the methane fermentation liquid C containing the organic waste B supplied to an upstream side to the treatment regions 3 at a downstream side, and each of the plurality of partition bodies 4 is provided with a warming part 6 capable of warming the methane fermentation liquid C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a methane fermentation apparatus and a methane fermentation method for treating organic waste by methane fermentation. [Background technology]

[0002] Methane fermentation (anaerobic fermentation) is widely used to reduce the volume of organic waste generated in wastewater treatment, such as sludge and biomass, and to convert it into energy. Methane fermentation is a technology in which organic matter is stored under anaerobic conditions for a certain period of time, and the organic waste is decomposed by anaerobic microorganisms to produce biogas such as methane gas and carbon dioxide. This technology is widely used in waste treatment facilities and wastewater treatment facilities in Japan.

[0003] A known methane fermentation apparatus includes a methane fermentation tank that subjects organic waste to methane fermentation and a plurality of compartments that divide the interior of the methane fermentation tank into a plurality of treatment zones (see, for example, Patent Document 1). In Patent Document 1, the methane fermentation tank is configured to supply organic waste input into the methane fermentation tank to a plurality of treatment zones, with organic waste supplied to the upstream side being sequentially moved to the downstream treatment zones. Patent Document 1 also includes a return section that returns a mixture of organic waste and methane fermentation liquid in the most downstream treatment zone of the methane fermentation tank to the most upstream treatment zone of the methane fermentation tank. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 04-017116 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to perform methane fermentation treatment, it is necessary to heat the methane fermentation liquid in the methane fermentation tank so that the temperature of the methane fermentation liquid is in a temperature range suitable for methane fermentation treatment. However, Patent Document 1 does not describe heating the methane fermentation liquid in the methane fermentation tank.

[0006] When heating the methane fermentation liquid in the methane fermentation tank, for example, a method of installing a hot water jacket in the methane fermentation tank to heat the entire methane fermentation tank, or a method of installing a heat exchanger in the return path that returns the mixture of organic waste and methane fermentation liquid in the return section to heat the mixture of organic waste and methane fermentation liquid, can be considered.

[0007] In the former case, installing a hot water jacket over the entire methane fermentation tank is costly and the device configuration is complicated, making it difficult to maintain. In the latter case, even if the temperature of the methane fermentation liquid in the upstream treatment zone is within the appropriate temperature range, the temperature of the methane fermentation liquid drops as it moves downstream, falling out of the appropriate temperature range, making it difficult to proceed with the methane fermentation process. Conversely, if the mixture of organic waste and methane fermentation liquid is heated to a high temperature in order to keep the temperature of the methane fermentation liquid in the downstream treatment zone within the appropriate temperature range, the temperature of the methane fermentation liquid in the upstream treatment zone will become higher than the appropriate temperature range, adversely affecting the microorganisms that contribute to the methane fermentation process.

[0008] In view of this situation, the main object of the present invention is to provide a methane fermentation apparatus and a methane fermentation method that can reduce costs, simplify the device configuration, be advantageous in terms of maintenance, and keep the temperature of the methane fermentation liquid in the methane fermentation tank within an appropriate temperature range. [Means for solving the problem]

[0009] A first characteristic configuration of the present invention is a methane fermentation tank for treating organic waste by methane fermentation, a plurality of partition bodies that partition the inside of the methane fermentation tank into a plurality of treatment regions, the methane fermentation tank is configured to supply the methane fermentation liquid containing the organic waste introduced into the methane fermentation tank to a plurality of treatment areas in a manner that the methane fermentation liquid containing the organic waste supplied to the upstream side is sequentially moved to a downstream treatment area, Each of the plurality of partitions is provided with a heating section capable of heating the methane fermentation liquid.

[0010] According to this configuration, the methane fermentation liquid can be heated by the heating unit provided in the partition body, so that a drop in the temperature of the methane fermentation liquid in the methane fermentation tank can be suppressed and the temperature can be maintained within an appropriate temperature range. Moreover, by providing a heating unit in the partition body for dividing the tank into multiple treatment areas, it is not necessary to provide a separate heating device for heating the organic waste or the methane fermentation liquid, which makes it possible to simplify the configuration while suppressing increases in costs and is advantageous in terms of maintenance and management.

[0011] A second characteristic feature of the present invention is that a sampling unit is provided for sampling the state of the organic waste in the plurality of treatment areas.

[0012] According to this configuration, by sampling the state of the organic waste in each treatment area using the sampling section, it is possible to grasp the change over time in the biodegradation reaction in each treatment area.

[0013] A third characteristic feature of the present invention is that a return section is provided for returning the mixture of methane fermentation liquid and organic waste in the downstream treatment area to the upstream treatment area.

[0014] According to this configuration, the amount of the mixture of methane fermentation liquid and organic waste returned by the return section can be freely set depending on conditions such as the processing status of the methane fermentation process, so that the methane fermentation process can be carried out optimally by turning the return on and off or changing the return amount. Furthermore, the return section returns the mixture of methane fermentation liquid and organic waste in the downstream processing area to the upstream processing area, thereby allowing the methane fermentation liquid and organic waste to be stirred. This eliminates the need to install an agitator in the methane fermentation tank, or even if an agitator is installed in the methane fermentation tank, the agitator can be made smaller, thereby simplifying the configuration and reducing costs.

[0015] A fourth characteristic configuration of the present invention is that the organic waste is mixed with the mixture returned by the return section to generate organic waste for input, and the generated organic waste for input is input into the methane fermentation tank.

[0016] According to this configuration, before being charged into the methane fermentation tank, the organic waste to be charged is mixed with the mixture returned by the return section, thereby generating organic waste to be charged. This eliminates the need to provide an agitator or the like in the methane fermentation tank, or, even if an agitator is provided in the methane fermentation tank, the agitator can be made smaller, thereby simplifying the configuration and reducing costs. Furthermore, because the organic waste is mixed with the mixture returned by the return section before being charged into the methane fermentation tank, the decomposition reaction of the organic waste begins before being charged into the methane fermentation tank due to the action of microorganisms in the mixture that contribute to the methane fermentation process, allowing biogas to be produced efficiently.

[0017] A fifth characteristic feature of the present invention is that the methane fermentation tank is provided with a separation section for separating solid matter including at least matter unsuitable for methane fermentation from the methane fermentation liquid.

[0018] According to this configuration, by providing a separation section within the methane fermentation tank, solid matter including substances unsuitable for methane fermentation can be separated from the methane fermentation liquid, thereby preventing solid matter including substances unsuitable for methane fermentation from remaining in other parts of the methane fermentation tank. For example, by providing a separation section in the upstream processing area, solids containing substances unsuitable for methane fermentation can be separated in the upstream processing area, effectively preventing solids containing substances unsuitable for methane fermentation from remaining in the downstream processing area.

[0019] A sixth characteristic configuration of the present invention is that a discharge part is provided for discharging solid matter containing matters unsuitable for methane fermentation separated in the separation part to the outside of the methane fermentation tank.

[0020] According to this configuration, the discharge section discharges solid matter, including matter unsuitable for methane fermentation, out of the methane fermentation tank, thereby preventing a decrease in the volume of methane fermentation liquid that can be stored in the methane fermentation tank and also preventing blockage of the flow path for the methane fermentation liquid.

[0021] A seventh characteristic configuration of the present invention is that the heating section provided in each of the plurality of partitions is configured so that the heating temperature at which the methane fermentation liquid is heated can be adjusted independently.

[0022] According to this configuration, the heating section provided in each of the multiple partitions can individually heat the methane fermentation liquid, so that in each of the multiple treatment areas, the methane fermentation liquid can be heated to a temperature range suitable for methane fermentation treatment, and the methane fermentation treatment can be carried out appropriately.

[0023] Furthermore, since the heating units provided in each of the multiple compartments can adjust the heating temperature at which the methane fermentation liquid is heated, it is possible to change the heating temperature of the methane fermentation liquid in each of the multiple treatment areas. For example, it is possible to mix a treatment area in which high-temperature methane fermentation treatment is performed using a temperature range suitable for methane fermentation treatment as the high-temperature side, and a treatment area in which medium-temperature methane fermentation treatment is performed using a temperature range suitable for methane fermentation treatment as the medium-temperature side. This makes it a suitable methane fermentation apparatus that can perform a combination of high-temperature methane fermentation treatment and medium-temperature methane fermentation treatment.

[0024] An eighth characteristic configuration of the present invention is a methane fermentation method for treating organic waste by methane fermentation in a methane fermentation tank, a supply process in which the methane fermentation liquid containing the organic waste introduced into the methane fermentation tank is supplied to the plurality of treatment areas in a state in which the inside of the methane fermentation tank is partitioned into a plurality of treatment areas by a plurality of partition bodies, and the methane fermentation liquid containing the organic waste supplied to the upstream side is sequentially moved to the downstream treatment area; The methane fermentation liquid is heated by a heating section provided in the partition body.

[0025] According to this configuration, the methane fermentation liquid can be heated by the heating unit provided in the partition body, so that a drop in the temperature of the methane fermentation liquid in the methane fermentation tank can be suppressed and the temperature can be maintained within an appropriate temperature range. Moreover, by providing a heating unit in the partition body for dividing the tank into multiple treatment areas, it is not necessary to provide a separate heating device for heating the organic waste or the methane fermentation liquid, which makes it possible to simplify the configuration while suppressing increases in costs and is advantageous in terms of maintenance and management. [Brief explanation of the drawings]

[0026] [Figure 1] A plan view showing the schematic configuration of a methane fermentation device. [Figure 2] A side view showing the schematic configuration of a methane fermentation apparatus. [Figure 3] View of the arrows III-III in Figure 1 [Figure 4] (A) is a view taken along the arrows IVA-IVA in Figure 1, and (B) is a view taken along the arrows IVB-IVB in Figure 1. DETAILED DESCRIPTION OF THE INVENTION

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A methane fermentation apparatus and a methane fermentation method according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1 and 2, the methane fermentation apparatus 1 is equipped with a methane fermentation tank 2 that performs methane fermentation treatment (anaerobic fermentation treatment) on organic waste B, such as sewage sludge and food waste. In the methane fermentation tank 2, the temperature of a methane fermentation liquid C containing organic waste B is maintained within a predetermined range and methane fermentation treatment is performed, thereby producing biogas D, such as methane gas.

[0028] As shown in Fig. 1, the methane fermentation tank 2 is formed in a circular shape in a plan view, and as shown in Fig. 2, it is provided with a bottomed, cylindrical tank body 21 that can store a methane fermentation liquid C containing organic waste B therein, and a lid 22 that closes the upper side of the tank body 21. In the methane fermentation tank 2, more than half of the height (vertical direction) of the methane fermentation tank 2 is a liquid phase section 23 that stores the methane fermentation liquid C, and the remaining upper part is a gas phase section 24 that does not store the methane fermentation liquid C. Incidentally, the shape of the methane fermentation tank 2 is not limited to a circle, and other shapes such as a polygon can also be used.

[0029] As shown in Figures 1 and 2, one side of the lateral part of the methane fermentation tank 2 (the left side in Figures 1 and 2) is the supply side for organic waste B, etc., and the opposite side to the one side of the lateral part (the right side in Figures 1 and 2) is the discharge side for biogas D, etc. As shown by the white arrows in Figures 1 and 2, organic waste B is introduced into the methane fermentation tank 2 from an input port 8 on the supply side (the left side in Figures 1 and 2) of the methane fermentation tank 2, and methane fermentation processing is carried out while a methane fermentation liquid C containing organic waste B is caused to flow within the methane fermentation tank 2, and the produced biogas D is extracted from the discharge side (the right side in Figures 1 and 2) of the methane fermentation tank 2. The extracted biogas D can be supplied to a biogas utilization facility, etc.

[0030] Since a methane fermentation liquid C containing organic waste B is flowing through the methane fermentation tank 2, the supply side of the organic waste B, etc. in the methane fermentation tank 2 (left side in Figures 1 and 2) is the upstream side in the flow direction of the methane fermentation liquid C, and the discharge side of the biogas D, etc. in the methane fermentation tank 2 (right side in Figures 1 and 2) is the downstream side in the flow direction of the methane fermentation liquid C.

[0031] Regarding directions, as shown in Fig. 1, the direction from the supply side to the discharge side of the methane fermentation tank 2 is referred to as a first direction X1, and the direction perpendicular to the first direction X1 is referred to as a second direction X2. With respect to the first direction X1, the right side of Fig. 1 is referred to as the downstream side of the first direction X1, and the left side of Fig. 1 is referred to as the upstream side of the first direction X1. The second direction X2 is indicated by the left-right direction when looking at the downstream side of the first direction X1, with the upper side of Fig. 1 being referred to as the left side of the second direction X2, and the lower side of Fig. 1 being referred to as the right side of the second direction X2.

[0032] As shown in FIGS. 1 and 2 , the methane fermentation tank 2 is provided with a plurality of partitions 4 that divide the interior of the methane fermentation tank 2 into a plurality of treatment zones 3. As shown in FIG. 1 , the partitions 4 are plate-shaped and arranged vertically inside the methane fermentation tank 2. Both ends of the partitions 4 are clamped by guides 26 arranged on the inner wall of the tank body 21, and the partitions 4 are positioned at a desired installation position. As shown in FIG. 2 , the upper ends of the partitions 4 do not reach the lid 22, and the partitions 4 are contained within the methane fermentation tank 2. Because the partitions 4 do not penetrate the lid 22, biogas D and the like do not leak from the methane fermentation tank 2 to the outside through the penetrations. Because there are no penetrations in the lid 22 for the partitions 4, for example, workers can walk on the top surface of the lid 22, facilitating inspection and repair of the lid 22. Because the partitions 4 are contained within the methane fermentation tank 2, the size of the partitions 4 does not need to be increased, thereby reducing costs.

[0033] 1 and 2, the partitions 4 are shown as being housed in the methane fermentation tank 2 without penetrating the lid 22. However, for example, the partitions 4 may be provided so as to penetrate the lid 22 in the vertical direction and protrude above the lid 22. When the partitions 4 penetrate the lid 22 in this manner, the treatment zones 3 can be partitioned into a plurality of treatment zones 3 without the gas phases 24 communicating with each other. Therefore, for example, by providing a sampling unit 9 in the gas phases 24 corresponding to each of the treatment zones 3, gas analysis can be performed in each of the treatment zones 3, making it easier to understand the state of the biodegradation reaction, etc. Furthermore, when the partitions 4 are to be attached or detached, the partitions 4 can be attached or detached without removing the lid 22, which simplifies the work of attaching and detaching the partitions 4. In the example of Figure 2, the gas phase section 24 is configured to be equipped with a sampling section, but it may also be possible to sample the methane fermentation liquid C, or it may be possible to provide both a sampling section for biogas D and a sampling section for the methane fermentation liquid, or it may be possible to provide either one of them.

[0034] 1 and 2, five partitions 4, first to fifth partitions 41-45, are installed at intervals from the upstream side to the downstream side in the first direction X1, and the interior of the methane fermentation tank 2 is partitioned into six treatment regions 3, first to sixth treatment regions 31-36. Furthermore, as shown in FIG. 1, in the second direction X2, the first treatment region 31 is partitioned into three small treatment regions 31a-31c by the first partition 41, and the sixth treatment region 36 is partitioned into two small treatment regions 36a-36b by the fifth partition 45. Therefore, the interior of the methane fermentation tank 2 is partitioned into a total of nine treatment regions 3, including the treatment regions 3 partitioned into smaller regions by the first to fifth partitions 41-45.

[0035] 1, the second to fourth partitions 42-44 are formed in a linear shape extending along the second direction X2 in a plan view. The lengths of the second partition 42 and the fourth partition 44 in the second direction X2 are set to be equal, and the third partition 43 is set to be longer than the second partition 42 and the fourth partition 44.

[0036] As shown in FIG. 1, the first partition 41 includes a linear portion 41a extending along the second direction X2 and a protruding portion 41b protruding from a midpoint of the linear portion 41a toward the upstream side in the first direction X1. Two protruding portions 41b are provided spaced apart in the second direction X2, dividing the first processing region 31 into three smaller processing regions 3: an upstream first processing region 31a, an intermediate first processing region 31b, and a downstream first processing region 31c. The upstream first processing region 31a, the intermediate first processing region 31b, and the downstream first processing region 31c are configured to have smaller volumes than the second to fifth processing regions 32-35. The upstream first processing region 31a and the downstream first processing region 31c are configured to have approximately the same volume, while the intermediate first processing region 31b is configured to have a smaller volume than the upstream first processing region 31a and the downstream first processing region 31c.

[0037] 1, the fifth partition 45, like the first partition 41, has a linear portion 45a and a protruding portion 45b. The protruding portion 45b protrudes downstream in the first direction X1, and divides the sixth processing region 36 into two smaller processing regions 3, an upstream sixth processing region 36a and a downstream sixth processing region 36b. The upstream sixth processing region 36a and the downstream sixth processing region 36b are set to have smaller volumes than the second to fifth processing regions 32-35. The downstream sixth processing region 36b is set to have a smaller volume than the upstream sixth processing region 36a.

[0038] The multiple treatment areas 3 are partitioned by multiple partition bodies 4, and in order to enable the flow of the methane fermentation liquid C, communication parts 5 that connect the treatment areas 3 to each other are provided, as shown in Figures 1 and 2. There are a total of nine treatment areas 3, including the smaller partitioned treatment areas 3, so there are eight communication parts 5, numbered 1 to 8, namely, first to eighth communication parts 51-58.

[0039] 1 and 3, the first communication section 51 communicates the upstream first processing region 31a with the intermediate first processing region 31b, and the second communication section 52 communicates the intermediate first processing region 31b with the downstream first processing region 31c. As shown in FIGS. 1 and 2, the third communication section 53 communicates the downstream first processing region 31c with the second processing region 32, and the fourth communication section 54 communicates the second processing region 32 with the third processing region 33. The fifth communication section 55 communicates the third processing region 33 with the fourth processing region 34, and the sixth communication section 56 communicates the fourth processing region 34 with the fifth processing region 35. The seventh communication section 57 communicates between the fifth processing region 35 and the upstream sixth processing region 36a, and the eighth communication section 58 communicates between the upstream sixth processing region 36a and the downstream sixth processing region 36b.

[0040] As shown in Figures 1 and 3, the first communication part 51 and the second communication part 52 are disposed at positions corresponding to the protruding part 41b of the first partition 41. As shown in Figure 3, the first communication part 51 is disposed at a lower end part of the methane fermentation tank 2, while the second communication part 52 is disposed at an upper end part of the methane fermentation tank 2, and are disposed on opposite sides in the up-down direction. The first communication part 51 is open from the bottom of the methane fermentation tank 2 to a desired height, and as shown by the outline arrow in Figure 3, the methane fermentation liquor C passes under the protruding part 41b of the first partition 41 and flows from the upstream first treatment region 31a into the intermediate first treatment region 31b. The second communication part 52 is disposed above the liquid level 25 which is the boundary between the liquid phase part 23 and the gas phase part 24. The methane fermentation liquid C flows from the intermediate first treatment region 31b into the downstream first treatment region 31c in an overflow manner, overflowing from the intermediate first treatment region 31b and flowing into the downstream first treatment region 31c, as shown by the white arrow in Figure 3.

[0041] 1 and 3, the third communication part 53 is disposed at a position corresponding to the right end (lower side in FIG. 1) of the straight part 41a of the first partition 41 in the second direction X2. In the vertical direction, as shown in FIG. 3, the third communication part 53 is disposed at a lower end part of the methane fermentation tank 2, similar to the first communication part 51, and similar to the first communication part 51, the methane fermentation liquid C passes downward and flows into the next treatment area 3. The fifth communication part 55 and the seventh communication part 57 are disposed at a position corresponding to the right end (lower side in FIG. 1) of the partition 4 in the second direction X2, similar to the third communication part 53, at a lower end part of the methane fermentation tank 2, similar to the first communication part 51, and therefore will not be described or illustrated in detail.

[0042] 1 and 4(A), the fourth communication part 54 is disposed at a position corresponding to the left end of the second partition 42 in the second direction X2 (upper side in FIG. 1). In the vertical direction, as shown in FIG. 4(A), the fourth communication part 54 is disposed at the upper end portion of the methane fermentation tank 2, similar to the second communication part 52, and the methane fermentation liquid C flows into the next treatment area 3 in an overflow manner, similar to the second communication part 52. The sixth communication part 56 is disposed at the upper end portion of the methane fermentation tank 2, similar to the fourth communication part 54, at a position corresponding to the left end of the partition 4 in the second direction X2 (upper side in FIG. 1), and therefore will not be described or illustrated in detail.

[0043] The eighth communication part 58 is disposed at a position corresponding to the protruding part 45b of the fifth partition 45, and although not shown, in the vertical direction it is disposed at the upper end side part of the methane fermentation tank 2, similar to the second communication part 52. Therefore, similar to the second communication part 52, the methane fermentation liquid C flows into the next treatment area 3 in an overflow manner.

[0044] Of the multiple treatment regions 3, the upstream first treatment region 31a is the target for input of organic waste B, and the upstream first treatment region 31a is the most upstream side in the flow direction of the methane fermentation liquid C. Of the multiple treatment regions 3, the downstream sixth treatment region 36b is the target for output of biogas D, etc., and the downstream sixth treatment region 36b is the most downstream side in the flow direction of the methane fermentation liquid C. Incidentally, with regard to the output of biogas D, it is also possible to adopt a configuration that allows the output of biogas D from each of the first to sixth treatment regions 31-36, regardless of whether the partitions 4 are configured not to penetrate the lid 22 or whether the partitions 4 are configured to penetrate the lid 22.

[0045] As a result, as shown by the white arrows in Figure 1, when organic waste B is input (supplied) at the input section 8 to the upstream first treatment area 31a, which is the most upstream side, the methane fermentation liquid C containing the organic waste B is pushed out and supplied to the next treatment area 3, and the methane fermentation liquid C circulates in the following order: upstream first treatment area 31a → intermediate first treatment area 31b → downstream first treatment area 31c → second treatment area 32 → third treatment area 33 → fourth treatment area 34 → fifth treatment area 35 → upstream sixth treatment area 36a → downstream sixth treatment area 36b.

[0046] The first to eighth communication parts 51-58 are arranged so that the lower end portions and upper end portions of the methane fermentation tank 2 alternate in the vertical direction from the upstream side to the downstream side in the flow direction of the methane fermentation liquid C. Therefore, as shown by the outline arrows in Fig. 2, the methane fermentation liquid C flows from the lower side portion to the upper side portion of the methane fermentation tank 2 or from the upper side portion to the lower side portion, and is supplied to the next treatment area 3.

[0047] 1, the upstream first treatment region 31a, the intermediate first treatment region 31b, the downstream first treatment region 31c, the upstream sixth treatment region 36a, and the downstream sixth treatment region 36b each have a communication section 5 disposed at both ends in the second direction X2. The third to seventh communication sections 53-57 are disposed from the upstream side to the downstream side in the flow direction of the methane fermentation liquid C so that their right ends (lower sides in FIG. 1) and left ends (upper sides in FIG. 1) in the second direction X2 alternate. Therefore, as shown by the outline arrows in FIG. 1, the methane fermentation liquid C flows from the right end to the left end or from the left end to the right end in the second direction X2 before being supplied to the next treatment region 3.

[0048] In this way, in the methane fermentation tank 2, as shown in Figures 1 and 2, the methane fermentation liquid C containing the organic waste B fed into the methane fermentation tank 2 is supplied to multiple treatment areas 3 in a manner that the methane fermentation liquid C containing the organic waste B fed to the upstream side is sequentially moved to the downstream treatment areas 3.

[0049] As shown in Figures 3 and 4, each of the multiple partitions 4 is provided with a heating unit 6 that can heat the methane fermentation liquid C. The heating unit 6 is configured as a hot water flow space 61 (see the dotted line in the partition 4 in Figures 3 and 4) formed inside the partition 4. The methane fermentation liquid C can be heated by flowing hot water through the hot water flow space 61. The hot water flow space 61 is formed throughout the partition 4 in the vertical and longitudinal directions, so the heating unit 6 can heat the methane fermentation liquid C throughout the entire partition 4.

[0050] As shown in Figures 1, 3, and 4, each of the multiple partitions 4 is provided with a hot water receiving section 62 that receives hot water to be passed through the hot water flow space 61, and a hot water discharge section 63 that discharges the hot water that has passed through the hot water flow space 61 to the outside. The hot water receiving section 62 is disposed at the left end in the second direction X2 (upper side in Figure 1, left side in Figures 3 and 4), and the hot water discharge section 63 is disposed at the right end in the second direction X2 (lower side in Figure 1, right side in Figures 3 and 4). As a result, hot water supplied to the hot water flow space 61 by the hot water receiving section 62 flows from the left end to the right end in the second direction X2 of the hot water flow space 61 and is discharged from the hot water discharge section 63, making it easy to pass hot water throughout the entire hot water flow space 61. Incidentally, the first partition 41 is provided with a hot water receiving portion 62 on the left protruding portion 41b in the second direction X2, and a hot water discharging portion 63 on the right protruding portion 41b in the second direction X2.

[0051] As shown in Figures 2 to 4, the hot water receiving portion 62 is a coupling member that connects the hot water supply path 65 to the partition body 4 in order to supply hot water from the hot water supply path 65 into the hot water flow space 61 of the partition body 4, and is disposed in an orientation extending in the vertical direction while passing through the cover body 22. As shown in Figure 3, the hot water receiving portion 62 is provided with a first coupling member 62a connected to the hot water supply path 65 side and attachable from the upper side of the cover body 22, a second coupling member 62b connected to the partition body 4 side, and a communicating connection member 62c that communicates between the first coupling member 62a and the second coupling member 62b. Incidentally, Figure 4 shows the state in which the cover body 22 and the first coupling member 62a and the communicating connection member 62c of the hot water receiving portion 62 are removed.

[0052] 3 and 4, the hot water discharge part 63 is a coupling member that connects the partition body 4 to the hot water discharge path 67 in order to discharge hot water in the hot water flow space 61 of the partition body 4 to the hot water discharge path 67, and is disposed in an orientation extending in the vertical direction while passing through the cover body 22. As shown in FIG. 3, the hot water discharge part 63 includes a third joint member 63a connected to the hot water discharge path 67 side and attachable from the upper side of the cover body 22, a fourth joint member 63b connected to the partition body 4 side, and a communicating connection member 63c that communicates between the third joint member 63a and the fourth joint member 63b. Incidentally, FIG. 4 shows the cover body 22 and the third joint member 63a and the communicating connection member 63c of the hot water discharge part 63 removed.

[0053] As shown in FIG. 4 , the hot water flow space 61 is provided with a hot water partition 68 that separates the space on the hot water receiving section 62 side from the space on the hot water discharge section 63 side in the second direction X2. The hot water partition 68 can be formed, for example, of a porous body and separates the space into the hot water receiving section 62 side and the hot water discharge section 63 side while allowing a certain amount of hot water to pass through. The hot water partition 68 is disposed so as to extend downward from the upper end of the hot water flow space 61. The length of the hot water partition 68 is set shorter than the overall length of the hot water flow space 61 in the up-down direction, and is disposed so as to form a gap with the lower end of the hot water flow space 61. This prevents the occurrence of a short path, in which hot water supplied from the hot water receiving section 62 flows directly toward the hot water discharge section 63 and is discharged from the hot water discharge section 63.

[0054] As shown in FIGS. 1 and 2 , a hot water supply unit 64 is provided to supply hot water to the hot water flow spaces 61 in each of the multiple partitions 4. The hot water supply unit 64 includes a hot water supply path 65 connected to each hot water receiving unit 62 and a hot water supply pump P1 that supplies hot water to each heating unit 6 through the hot water supply path 65. The hot water supply path 65 is connected in parallel to the multiple hot water receiving units 62, allowing hot water to be supplied to all of the multiple hot water receiving units 62. By operating the hot water supply pump P1, hot water from a hot water supply source (not shown) is supplied to each hot water receiving unit 62 through the hot water supply path 65, thereby supplying hot water to each of the multiple hot water flow spaces 61. A hot water discharge path 67 is connected to each hot water discharge unit 63, and hot water discharged from each hot water discharge unit 63 can be returned to the hot water supply source (not shown) through the hot water discharge path 67. Incidentally, it is possible to provide multiple hot water supply pumps P1 instead of one. For example, the same number of hot water supply pumps P1 as the number of hot water receiving sections 62 can be provided, and hot water can be supplied to each hot water receiving section 62 by each hot water supply pump P1. When multiple hot water supply pumps P1 are provided, the multiple hot water supply pumps P1 can be operated in sequence, for example, by arranging the multiple hot water supply pumps P1 in parallel and operating them alternately. Furthermore, a valve capable of adjusting the hot water flow rate may be attached to the hot water receiving section 62, and the amount of hot water supplied to each partition 4 may be adjusted by adjusting the opening of the valve, or the amount of hot water supplied to each partition 4 may be adjusted by operating the power of the hot water supply pump P1.

[0055] When heating the methane fermentation liquid C in the heating unit 6, the heating temperature can be changed as appropriate, but for example, the heating temperature can be set so that the temperature of the methane fermentation liquid C is within a predetermined range of temperatures appropriate for methane fermentation treatment. Regarding the heating temperature, a constant heating temperature can be set in all of the multiple heating units 6, but it is also possible to configure the heating temperature in each of the multiple heating units 6 to be freely adjustable individually.

[0056] For example, by providing each of the hot water supply paths 65 with a supply amount adjustment valve or the like that can adjust the amount of hot water supplied, the amount of hot water supplied can be adjusted separately for each heating unit 6 (each hot water flow space 61). Therefore, if the heating temperature is adjusted separately for each of the multiple heating units 6, the amount of hot water supplied to each heating unit 6 (each hot water flow space 61) can be adjusted to correspond to each adjusted heating temperature. In addition, the supply amount adjustment valve or the like can be used to turn on and off the supply of hot water to each heating unit 6 (each hot water flow space 61). For example, the hot water temperature from the hot water supply source can be adjusted to a first set temperature, and hot water at the first set temperature can be supplied to only some of the multiple heating units 6 (hot water flow spaces 61), and the hot water temperature from the hot water supply source can be adjusted to a second set temperature, and hot water at the second set temperature can be supplied to only some of the multiple heating units 6 (hot water flow spaces 61). Therefore, by adjusting the temperature of the hot water supplied to each heating section 6 (each hot water flow space 61), it is possible to correspond to the individually adjusted heating temperature. Furthermore, by providing a heating member or the like in the partition body 4, it is possible to change the amount of heat of each heating section 6 and correspond to the individually adjusted heating temperature.

[0057] In this way, even if the heating temperature is adjusted separately in each of the multiple heating sections 6, the methane fermentation liquid C can be heated to the individually adjusted heating temperature, so the temperature of the methane fermentation liquid C can be maintained within a predetermined range of appropriate temperatures for the methane fermentation process.

[0058] Regarding the predetermined range of optimum temperatures in methane fermentation treatment, when methane fermentation treatment is performed at a medium temperature, the predetermined range of optimum temperatures can be set to, for example, a temperature range of 30°C to 45°C, and when methane fermentation treatment is performed at a high temperature, the predetermined range of optimum temperatures can be set to, for example, a temperature range of 50°C to 60°C.

[0059] Furthermore, it is possible to mix a processing zone 3 in which high-temperature methane fermentation processing is performed using a temperature range suitable for methane fermentation processing as the high-temperature side, and a processing zone 3 in which meso-temperature methane fermentation processing is performed using a temperature range suitable for methane fermentation processing as the meso-temperature side. This results in a suitable methane fermentation apparatus 1 that can perform a combination of high-temperature methane fermentation processing and meso-temperature methane fermentation processing. In this case, it is possible to appropriately change which processing zone 3 has the high-temperature side temperature range, but for example, it is possible to have multiple upstream processing zones 3 have the high-temperature side temperature range and multiple downstream processing zones 3 have the meso-temperature side temperature range.

[0060] As shown in Figures 1 and 2, the downstream sixth treatment area 36b in the methane fermentation tank 2 is a target for extracting biogas D and the like. In addition to extracting biogas D from the downstream sixth treatment area 36b, as shown in Figure 2, a return section 7 is provided that returns a mixture E of methane fermentation liquid C and organic waste B in the downstream sixth treatment area 36b to the upstream treatment area 3.

[0061] As shown in Figure 2, the return section 7 is equipped with a return path 71 that guides the mixture E from the downstream sixth treatment area 36b to the input section 8 of the methane fermentation tank 2, and a return pump P2 that removes the mixture E from the lower part of the downstream sixth treatment area 36b and returns the mixture E to the input section 8 through the return path 71.

[0062] The timing at which the return pump P2 is operated can be changed as appropriate, and for example, the timing at which the return pump P2 is operated and the number of times it is operated can be freely set depending on conditions such as the processing status of the methane fermentation process. In addition, the amount of mixture E returned can also be changed as appropriate depending on conditions such as the processing status of the methane fermentation process.

[0063] In FIG. 2 , the return section 7 returns the mixture E from the most downstream treatment zone 3 to the input section 8. However, the return destination of the mixture E can be changed as appropriate, for example, by returning the mixture E from the most downstream treatment zone 3 to the most upstream treatment zone 3. Furthermore, the destination from which the mixture E is removed is not limited to the most downstream treatment zone 3, and the mixture E can also be removed from another treatment zone 3. Therefore, the return section 7 only needs to return the mixture E to at least one treatment zone 3 among the treatment zones 3 excluding the most upstream treatment zone 3, and to at least one treatment zone 3 among the treatment zones 3 upstream of that treatment zone 3. Specifically, returning the mixture E from the second treatment zone 32 to the first treatment zone 31 is preferable because acid fermentation is promoted, and returning the mixture E from the sixth treatment zone 36 to the third treatment zone 33 is preferable because methane fermentation is promoted.

[0064] The input unit 8 inputs organic waste B into the methane fermentation tank 2, but as shown in Figure 2, the return unit 7 returns the mixture E, so it is possible to generate organic waste F for input by mixing the organic waste B with the mixture E, and then input the generated organic waste F for input into the methane fermentation tank 2. In this way, when the return unit 7 returns the mixture E, the input unit 8 generates organic waste F for input by mixing the organic waste B with the mixture E before input into the methane fermentation tank 2, so that the action of microorganisms in the mixture E that contribute to the methane fermentation process begins the decomposition reaction of the organic waste B before input into the methane fermentation tank 2, and biogas D can be efficiently obtained.

[0065] Since the methane fermentation liquid C in the methane fermentation tank 2 contains materials unsuitable for methane fermentation treatment, the methane fermentation tank 2 is provided with a separation unit 10 that separates solid matter G containing materials unsuitable for methane fermentation, as shown in Fig. 3. The separation unit 10 has a first communication unit 51 disposed in a lower portion of the methane fermentation tank 2, and causes the methane fermentation liquid C to sink downward and flow into the next treatment area 3, thereby causing the solid matter G to settle and accumulate at the lower end of the methane fermentation tank 2 and separating the solid matter G from the methane fermentation liquid C.

[0066] 3, the separation unit 10 is disposed between the first upstream treatment region 31a, which is the most upstream region, and the first intermediate treatment region 31b, which is the second most upstream region, among the plurality of treatment regions 3. This allows the solids G to be separated from the methane fermentation liquid C at the most upstream side in the flow direction of the methane fermentation liquid C in the methane fermentation tank 2, and therefore, the solids G can be effectively prevented from remaining in the treatment region 3 downstream of the separation unit 10.

[0067] 3, a discharge section 11 is provided for discharging the solid matter G separated in the separation section 10 to the outside of the methane fermentation tank 2. The discharge section 11 can be configured with a discharge pump or the like that can freely discharge the solid matter G to the outside of the methane fermentation tank 2.

[0068] As shown in Figure 2, the methane fermentation tank 2 is equipped with sampling units 9 that sample the state of organic waste B in the multiple treatment areas 3. The sampling unit 9 is equipped with first to sixth sampling units 91-96 that correspond to the first to sixth treatment areas 31-36, respectively. This makes it possible to grasp changes over time in the biodegradation reaction in each treatment area, and therefore it is also possible to manage the amount and number of returns of the mixture E by the return unit 7, the heating temperature by each heating unit 6 (hot water flow space 61), and the like, depending on changes over time in the biodegradation reaction in each treatment area.

[0069] The sampling unit 9 may be provided in a state corresponding to each of the first to sixth treatment regions 31-36, or may be provided in only one of the first to sixth treatment regions 31-36, since the treatment regions 3 are connected via the gas phase section 24. When the sampling unit 9 is provided in a state corresponding to each of the first to sixth treatment regions 31-36, it is preferable to place the sampling unit 9 below the upper end of the partition body 4 and above the liquid level 25 of the methane fermentation tank 2, as shown in Fig. 2. In the example of Fig. 2, the sampling unit is configured to be provided in the gas phase section 24, but it may also be possible to sample the methane fermentation liquid C, or both or either a sampling unit for biogas D and a sampling unit for the methane fermentation liquid may be provided.

[0070] In this embodiment, as a methane fermentation method for subjecting organic waste B to methane fermentation in a methane fermentation tank 2, a supply process is carried out in which the methane fermentation liquid C containing organic waste B introduced into the methane fermentation tank 2 is supplied to the plurality of treatment regions 3, with the interior of the methane fermentation tank 2 partitioned into a plurality of treatment regions 3 by a plurality of partition bodies 4, and the methane fermentation liquid C containing organic waste B supplied to the upstream side is sequentially moved to the downstream treatment region 3, and a heating process is carried out in which the methane fermentation liquid C is heated in a heating unit 6 provided in the partition body 4.

[0071] Although the present invention relates to a methane fermentation process, it can also be applied to any anaerobic process, such as a hydrogen fermentation process.

[0072] [Another embodiment] Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments.

[0073] (1) In the above embodiment, the interior of the methane fermentation tank 2 is divided into nine treatment areas 3 by a plurality of partitions 4, but the number of partitioned treatment areas 3 can be changed as appropriate. The shape of each treatment area 3 can also be changed as appropriate. Furthermore, the material of the partitions 4 is not particularly limited, but stainless steel is preferable because it can transfer heat from the hot water to the methane fermentation liquid C and has excellent corrosion resistance.

[0074] (2) In the above embodiment, when the hot water supply unit 64 supplies hot water to multiple heating units 6 (hot water flow spaces 61), the hot water flows from the left to the right in the second direction X2. However, for example, the hot water can also be flowed in the opposite direction (opposite) to the flow direction of the methane fermentation liquid C, and the direction in which the hot water flows can be changed as appropriate.

[0075] (3) In the above embodiment, the methane fermentation tank 2 is not provided with an agitator for agitating the organic waste B and the methane fermentation liquid C. However, an agitation pump for agitating the organic waste B and the methane fermentation liquid C can also be provided outside the methane fermentation tank 2. [Explanation of symbols]

[0076] 1. Methane fermentation equipment 2. Methane fermentation tank 3 Processing area 4 Partitions 6 Heating section 7 Return Department 9 Sampling section 10 Separation section 11 Discharge section B. Organic waste C. Methane fermentation liquid E. Mixture of organic waste and methane fermentation liquid F Organic waste for input G. Solids containing materials unsuitable for methane fermentation

Claims

1. a methane fermentation tank for treating organic waste through methane fermentation; a plurality of partition bodies that partition the inside of the methane fermentation tank into a plurality of treatment regions, the methane fermentation tank is configured to supply the methane fermentation liquid containing the organic waste introduced into the methane fermentation tank to a plurality of treatment areas in a manner that the methane fermentation liquid containing the organic waste supplied to the upstream side is sequentially moved to a downstream treatment area, A methane fermentation apparatus, wherein each of the plurality of partitions is provided with a heating section capable of heating the methane fermentation liquid.

2. 2. The methane fermentation apparatus according to claim 1, further comprising a sampling unit for sampling the state of the organic waste in the plurality of treatment areas.

3. 3. The methane fermentation apparatus according to claim 1, further comprising a return section for returning the mixture of methane fermentation liquid and organic waste in the downstream treatment area to the upstream treatment area.

4. 4. The methane fermentation apparatus according to claim 3, wherein the organic waste is mixed with the mixture returned by the return section to produce organic waste for input, and the produced organic waste for input is input into the methane fermentation tank.

5. 3. The methane fermentation apparatus according to claim 1, wherein the methane fermentation tank is provided with a separation section for separating solid matter including at least matter unsuitable for methane fermentation from the methane fermentation liquid.

6. 6. The methane fermentation apparatus according to claim 5, further comprising a discharge section for discharging solid matter, including matter unsuitable for methane fermentation, separated in the separation section to the outside of the methane fermentation tank.

7. 3. The methane fermentation apparatus according to claim 1, wherein the heating section provided in each of the plurality of partitions is configured so that the heating temperature at which the methane fermentation liquid is heated can be adjusted independently.

8. A methane fermentation method for subjecting organic waste to methane fermentation in a methane fermentation tank, a supply process in which the methane fermentation liquid containing the organic waste introduced into the methane fermentation tank is supplied to the plurality of treatment areas in a state in which the inside of the methane fermentation tank is partitioned into a plurality of treatment areas by a plurality of partition bodies, and the methane fermentation liquid containing the organic waste supplied to the upstream side is sequentially moved to the downstream treatment area; and a heating process for heating the methane fermentation liquid in a heating section provided in the partition body.

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