JP2012166190A - Fermentation treatment device, and method for generating combustible gas by fermentation treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fermentation treatment device which reduces the agitation power of a fermentation tank, improves maintainability of an agitator in the fermentation tank and improves fermentation treatment efficiency, and also to provide a method for generating a combustible gas by the fermentation treatment.SOLUTION: The fermentation treatment device comprises: a first fermentation tank which can form a revolving upflow of a liquid to be fermented from beneath to an upper direction; a second fermentation tank which has an upper inflow part connected to an upper outflow part provided to the first fermentation tank and can form a revolving downflow of the liquid to be fermented from above to a lower direction by the flow of the liquid of the revolving upflow flowing from the upper outflow part to the upper inflow part; and a circulation part which supplies the liquid from the second fermentation tank to the first fermentation tank by connecting an intermediate outflow part provided to the second fermentation tank to the lower inflow part provided to the first fermentation tank.

Description

  The present invention relates to a method for producing a combustible gas by performing a fermentation treatment while circulating a liquid to be fermented between a first fermenter and a second fermenter, and a fermentation treatment apparatus used therefor.

  Generally, there are a mechanical stirring method and a gas stirring method as a method for performing the fermentation treatment while stirring the liquid to be fermented. The purpose of this stirring is to mix the input and sludge in the tank, to equalize the temperature in the tank, to separate the gas adhering to the sludge particles, to remove the scum in the tank, and to remove the sediment in the tank. It is done.

  The mechanical agitation method includes a method in which a vertical agitator is hung from the upper part of the tank and agitated with a stirring blade, a method in which an underwater agitator is introduced into the tank, and agitation is performed. Advantages of this mechanical stirring method include that it can be stirred as desired at a place where stirring is desired, and that it can be stirred with lower power than gas stirring. On the other hand, the disadvantages of this method are that the stirring efficiency is narrow and the sludge is short-circuited easily. Therefore, in order to perform efficient stirring, a large number of sets of the fermenter tank and the stirrer are required. In addition, scum or the like may be entangled with the stirring blade. In the case of an underwater stirrer, since the movable part is inside, the tank must be opened and taken out during maintenance. In the case of a vertical stirrer, a load such as a motor is applied to the upper part of the tank, so that it is necessary to sufficiently design the roof strength and side wall strength of the tank.

  In addition, the gas agitation method is a method in which biogas is injected by a gas compressor or the like in the fermenter tank, and the inside of the tank is agitated due to the gas rising effect. Advantages of this gas agitation method include that the agitation force is constant even when the liquid level fluctuates, that the agitation force is large, and that there are no moving parts inside the tank, so there are few failures. On the other hand, the disadvantages of this method are that the use of a roots blower and a gas compressor increases the power, and that a safety device such as a safety valve is required in the gas line to handle combustible gas.

  In Patent Document 1, the upper opening and the lower opening of the reaction tank are connected via an external circulation flow path, and the liquid in the tank is separated into solid and liquid by a membrane separation device arranged in the external circulation flow path. However, it is disclosed that the liquid in the tank is circulated and stirred. Moreover, in patent document 2, in the anaerobic biological treatment method which isolate | separated the acid production | generation part (tank) and the methane production | generation part (tank), when pH of an acid production | generation part falls below a predetermined value, to a methane production | generation part. It is disclosed that the acid generator is maintained in the optimum pH range by returning a part or all of the treated water to the acid generator.

JP 2001-170631 A JP 2000-167487 A

  Therefore, the present invention has been made in view of the current state of the prior art described above, which improves the disadvantages of the mechanical stirring method and the gas stirring method, reduces the stirring power of the fermenter, and improves the maintainability of the stirring device and the like. The present invention provides a fermentation treatment apparatus and a method for generating a combustible gas in a fermentation treatment for the purpose of improving fermentation treatment efficiency.

The present invention is a first fermenter capable of forming a swirl upward flow of the liquid to be fermented from below to above,
The upper inflow part connected to the upper outflow part provided in the first fermenter has an upper inflow part, and the flow of the fermented liquid in the swirling upward flow that has flowed from the upper outflow part to the upper inflow part A second fermenter capable of forming a downward swirling flow of the liquid to be fermented downward;
The intermediate outflow part provided in the second fermenter is connected to the lower inflow part provided in the lower stage of the first fermenter, and the liquid to be fermented is supplied from the second fermenter to the first fermenter. And a circulation processing unit.

  With this configuration, the first fermenter and the second fermenter are connected (connected) by connecting their upper parts (upper outflow part and upper inflow part) with pipes, for example, and lower than the upper parts (intermediate) In the outflow part and the lower inflow part), the circulation part is connected (coupled), and the fermentation process can be performed while turning the fermented liquid in the first and second fermenters. Thereby, compared with a mechanical stirring system and a gas stirring system, since it becomes possible to perform a fermentation process without performing excessive stirring, the stirring power of a fermenter can be reduced. Moreover, since the pump part (pump function for feeding the liquid to be fermented from the second fermenter to the first fermenter) corresponding to the stirring device is installed on the ground outside the fermenter, it can be maintained outside. Maintainability can be improved. Further, the strengths of the swirl upward flow in the first fermenter and the swirl downward flow in the second fermenter are set not to be uniform but to decrease stepwise, that is, the first The swirl downward flow in the second fermenter is weakened in a stepwise manner (the flow velocity is also smaller) than the swirl upward flow in the fermenter, and the liquid to be fermented (fermented sludge (residue)) in the second fermentor ) Is concentrated (place to precipitate). Thereby, combustible gas can be obtained from both the 1st fermenter upper part and the 2nd fermenter upper part, and fermentation processing efficiency can be improved.

  The raw material of the liquid to be fermented to be introduced into the fermenter is not particularly limited, but is preferably, for example, biomass (garbage, livestock manure, sewage sludge, food waste, etc.), and its water content is 90% or more. Preferably there is. The temperature of the raw material of the liquid to be fermented is preferably adjusted before being introduced into the fermenter. For example, the temperature is adjusted in the range of 20 to 60 ° C, and is 30 to 40 ° C (medium temperature) or 50 to 60 ° C (high temperature). It is more preferable that the temperature is adjusted.

  In the above invention, it is preferable that a middle inflow portion is further provided in the middle stage of the first fermentor and above the lower inflow portion. For example, it branches from the circulation part (piping part) connected from the intermediate | middle outflow part of the 2nd fermenter to the lower inflow part of the 1st fermenter, and lowers the to-be-fermented liquid from a 2nd fermenter to this middle inflow part. It feeds in the same way as the inflow part. Thereby, the turning speed of the swirling upward flow in the first fermenter can be accelerated at the middle position, and the swirling speed of the swirling upward flow can be maintained so as not to be attenuated. Both the lower inflow part and the middle inflow part are directed in the direction of accelerating the turning, and the turning of the turning upward flow is accelerated by the inflow of the liquid to be fermented. In addition, the circulation medium sent into the middle inflow part is not limited to the liquid to be treated circulated from the intermediate outflow part of the second fermentation tank, and may be a fermentation residue or the like to be described later.

  The position of the middle inflow part of the fermenter is from 0.25 to 0.8, more preferably from 0.4 to 0.00 when the distance to the liquid level is 1 from the bottom of the fermenter toward the liquid level. 75. Moreover, the ratio of the inflow amount in the lower inflow part and the middle inflow part is preferably in the range of lower part: middle part = 25: 75 to 75:25.

  The said invention WHEREIN: It is preferable to further provide the raw material supply line which has arrange | positioned the raw material supply pump part for throwing in the raw material of the said to-be-fermented liquid downstream of the pump part of the said circulation part. When charging the raw material of the liquid to be fermented into the first fermenter (feeding the raw material), the pump part for supplying the raw material and the pump part of the circulating part are operated by putting them downstream of the pump part of the circulating part. The raw material can be supplied along the circulation flow of the liquid to be fermented, and further, the raw material can be dispersed while swirling in the first fermenter, so that the dispersion effect of the raw material is great and the fermentation efficiency is also increased.

As one embodiment of the above invention, the lower inflow portion and the upper outflow portion of the first fermenter have an inflow direction of the fermented liquid in the lower inflow portion and an outflow direction of the fermented liquid in the upper outflow portion, Provided in a cross-sectional view different from the direction toward the central axis of the first fermentor,
The upper inflow part of the second fermenter is provided such that the inflow direction of the liquid to be fermented in the upper inflow part is different from the direction toward the central axis of the second fermenter in a cross-sectional view. Furthermore, the intermediate outflow portion of the second fermenter is provided such that the outflow direction of the liquid to be fermented in the intermediate outflow portion is different from the direction toward the central axis of the second fermenter in a cross-sectional view. Is preferred. In addition, the middle inflow portion is provided such that the inflow direction of the circulation medium (for example, the liquid to be fermented) in the middle inflow portion is different from the direction toward the central axis of the first fermenter in a cross-sectional view ( A configuration similar to the lower inflow portion is preferable).

  With this configuration, the upper inflow at the lower part of the first fermenter and the outlet of the upper outflow part in the tangential direction with a circular cross section of the first fermenter are used for turning upward by the power of the pump part of the circulation part. By turning the inlet of the upper inflow part of the second fermenter into a tangential direction with a circular cross section of the second fermenter, a swirling downward flow can be generated. Furthermore, the outlet of the intermediate outflow part of the second fermenter is preferably set in a tangential direction with a circular cross section of the second fermenter, so that a swirling downward flow can be generated more effectively.

As one embodiment of the invention, the second fermenter has a recovery port for recovering fermentation residues below the intermediate outflow part,
A residue circulation line is further provided for supplying the fermentation residue recovered from the recovery port of the second fermenter to the first fermentor.

  With this configuration, the fermentation residue can be recovered, and the fermentation residue can be reintroduced into the first fermentation tank by the pump unit of the residue circulation line. It is preferable that one end of the residue circulation line is connected to the recovery port portion and the other end is connected to the downstream side of the pump portion of the circulation portion.

  As a circulating medium sent to the middle inflow part, the fermentation residue (for example, concentrated methane fermentation sludge) discharged from the second fermenter can be directly sent to the middle inflow part by the pump part. Here, a second residue circulation line from the second fermenter to the middle inflow portion is formed.

  As an embodiment of the above invention, the residue circulation line preferably includes a solid-liquid separation device.

  With this configuration, after separating the liquid content and the solid content in the fermentation residue, the solid content residue (moisture content is, for example, 75 to 97%) can be re-introduced into the first fermenter. The concentration of can be increased. It is preferable that the residue circulation line has a path for discharging the filtrate and a path for returning the residue on the downstream side of the solid-liquid separator, and a pump unit is installed in the path for returning the residue.

  As a circulating medium fed into the middle inflow part, the fermentation residue discharged from the second fermenter and separated from the filtrate by the solid-liquid separator can be directly fed into the middle inflow part by the pump part. Here, a third residue circulation line from the second fermenter to the middle inflow part via the solid-liquid separator is formed.

  As one embodiment of the invention, a steam supply line is further provided for feeding steam obtained by burning the combustible gas generated in the first and second fermenters into the second fermenter.

  With this configuration, combustible gas is burned in, for example, a boiler to generate steam, and this steam is sent as a downward flow into the second fermentation tank, so that scum removal and heating (for fermentation promotion) are performed simultaneously. be able to. This steam supply line may feed steam by introducing steam supply piping into the second fermenter, or may feed steam so as to form a swirling downward flow.

  As one embodiment of the invention, the steam obtained by burning the combustible gas generated in the first and second fermenters is supplied to the first fermentor in order to heat the liquid to be fermented. A heating steam supply line is further provided.

  With this configuration, combustible gas is burned in, for example, a boiler to generate steam, and this steam is used for heating the fermented liquid in the first fermenter (for fermentation promotion), winding up the precipitate, etc. Can do. This steam supply line can be connected to the first fermenter jacket to heat the first fermenter, and the steam can be directly fed into the first fermenter by directing the pipe into the first fermenter. Steam may be fed so as to have an upward flow. Moreover, this steam can be utilized for heating the raw material thrown into a 1st fermenter.

  As one Embodiment of the said invention, it is preferable that the said 1st, 2nd fermenter is a vertically long cylindrical shape. As a result, the conventional mechanical agitation method device used a large fermenter (tank) and the construction period was long, but according to the present invention, the device is assembled at the factory and only installed on site, The construction period can be dramatically shortened. Further, in a vertically long fermenter having a cylindrical shape (cross-sectional circle), the water depth (water depth / diameter) with respect to the diameter is preferably 1 to 5, more preferably 2.3 to 3.6. 6 to 3.3 are more preferable. The reason for this is to facilitate the generation of swirl upward and downward flow.

  Fermentation treated in the first and second fermenters is not particularly limited, and examples thereof include hydrogen fermentation, methane fermentation, alcohol fermentation, lactic acid fermentation, butyric acid type fermentation, butanol-acetone type fermentation, nitrate fermentation or acetic acid fermentation. In particular, when the raw material is set to biomass, hydrogen fermentation and methane fermentation (anaerobic fermentation) are preferable.

Another aspect of the present invention is a method for producing a combustible gas by performing a fermentation process while circulating a liquid to be fermented between a first fermenter and a second fermenter,
A swirl upward flow forming step for forming a swirl upward flow from below to above the liquid to be fermented in the first fermentor;
A swirl downward flow of the liquid to be fermented from top to bottom is formed by the flow of the liquid to be fermented in the swirl upward flow that has flowed from the upper outflow part of the first fermenter to the upper inflow part of the second fermenter. A swirling downward flow forming step,
A circulation step of circulating the liquid to be fermented from the intermediate outflow part of the second fermenter to the lower inflow part provided in the lower stage of the first fermenter.

  With this configuration, the first fermenter and the second fermenter are connected (connected) by connecting their upper parts (upper outflow part and upper inflow part) with pipes, for example, and lower than the upper parts (intermediate) A combustible gas can be generated by connecting (connecting) the circulation part in the outflow part and the lower inflow part) and performing a fermentation process while turning the liquid to be fermented in the first and second fermenters.

  In the above invention, it is preferable that the method further includes a second circulation step of supplying a circulation medium to a middle inflow portion provided in the middle stage of the first fermenter and above the lower inflow portion. For example, it branches from the circulation part (piping part) connected from the intermediate | middle outflow part of the 2nd fermenter to the lower inflow part of the 1st fermenter, and lowers the to-be-fermented liquid from a 2nd fermenter to this middle inflow part. It feeds in the same way as the inflow part. Thereby, the turning speed of the swirling upward flow in the first fermenter can be accelerated at the middle position, and the swirling speed of the swirling upward flow can be maintained so as not to be attenuated. Both the lower inflow part and the middle inflow part are directed in the direction of accelerating the turning, and the turning of the turning upward flow is accelerated by the inflow of the liquid to be fermented.

  In the said invention, it is preferable to further include the raw material supply step which throws in the raw material of the said to-be-fermented liquid in the downstream of the circulation pump part used at the said circulation step. By feeding it downstream of the circulation pump, the raw material supply pump unit and the circulation pump can be operated to supply the raw material along the circulation flow of the liquid to be fermented. Since it can disperse | distribute, turning in a tank, the dispersion | distribution effect of a raw material is large and fermentation efficiency also becomes high.

  As one embodiment of the invention, a recovery step of recovering a fermentation residue from the bottom of the second fermenter, and a residue circulation step of supplying the fermentation residue recovered in the recovery step to the first fermentor Including. With this configuration, the fermentation residue can be recovered and the fermentation residue can be reintroduced into the first fermenter.

  As one embodiment of the invention described above, the method further includes a steam supply step of feeding steam obtained by burning the combustible gas generated in the first and second fermenters into the second fermenter. With this configuration, combustible gas is burned in, for example, a boiler to generate steam, and this steam is sent as a downward flow into the second fermentation tank, so that scum removal and heating (for fermentation promotion) are performed simultaneously. be able to.

  As one embodiment of the invention, the steam obtained by burning the combustible gas generated in the first and second fermenters is supplied to the first fermentor in order to heat the liquid to be fermented. A heating steam supply step is further included. With this configuration, combustible gas is burned in, for example, a boiler to generate steam, and this steam is used for heating the fermented liquid in the first fermenter (for fermentation promotion), winding up the precipitate, etc. Can do.

It is a figure for demonstrating the fermentation processing apparatus of Embodiment 1. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 2. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 3. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 4. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 5. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 6. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 7. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 8. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 9. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 10. FIG. It is a figure for demonstrating the fermentation processing apparatus of Embodiment 11. FIG. It is a velocity contour map in an experimental example.

(Embodiment 1)
The fermentation processing apparatus of Embodiment 1 is demonstrated referring FIG. Fig.1 (a) has the 1st fermenter 10, the 2nd fermenter 20, and the circulation part 2 (circulation line). The 1st fermenter 10 is a shape which can form the turning upward flow 101 of a to-be-fermented liquid from the bottom upwards, and is a vertically long cylindrical shape (cross-sectional circle). The 2nd fermenter 20 is a shape which can form the rotation downward flow 201 of a to-be-fermented liquid from the top to the downward direction, and is a vertically long cylindrical shape (cross-section circle). The upper outflow part 12 provided in the upper part of the 1st fermenter 10 and the upper inflow part 21 provided in the upper part of the 2nd fermenter 20 are connected by the piping 3, and a to-be-processed liquid is from the 1st fermenter 10. It flows into the second fermenter 20. Moreover, the intermediate outflow part 22 provided in the intermediate part of the 2nd fermenter 2 and the inflow part 11 provided in the lower part of the 1st fermenter 10 are connected via the circulation part 2, and the circulation part 2 is connected to the circulation part 2. A pump P <b> 2 is installed to feed the liquid to be fermented from the second fermenter 20 to the first fermenter 10. The circulation unit 2 (pump P2) has a function of circulating the liquid to be treated from the first fermentation tank 10 to the second fermentation tank 20. The circulation unit 2 can be configured with a pipe. The swirling upward flow 101 is greater in strength and flow velocity than the swirling downward flow 201 and is represented by the thickness of the arrow in FIG.

  Moreover, the lower inflow part 11 and the upper outflow part 12 of the 1st fermentation tank 10 are the 1st fermentation by the cross-sectional view in the inflow direction of the to-be-fermented liquid in the lower inflow part 11, and the outflow direction of the to-be-fermented liquid in the upper outflow part 12. It is provided so as to be different from the direction toward the central axis of the tank 10. Moreover, the upper inflow part 21 of the 2nd fermenter 20 is provided so that the inflow direction of the to-be-fermented liquid in the upper inflow part 21 may differ from the direction which goes to the center axis | shaft of the 2nd fermenter 20 by sectional view. The outflow part 22 is provided so that the outflow direction of the liquid to be fermented in the intermediate outflow part 22 is different from the direction toward the central axis of the second fermenter 20 in a cross-sectional view. That is, by turning the inlet of the lower inflow part 11 and the outlet of the upper outflow part 12 of the first fermenter 10 in the tangential direction of the cross section of the first fermenter 10, it is turned by the power of the pump P <b> 2 of the circulation part 2. An upward flow is generated, and the inlet of the upper inflow portion 21 of the second fermenter 20 is set in a tangential direction with a circular cross section of the second fermenter 20, thereby generating a swirling downward flow. Furthermore, by making the outlet of the intermediate outflow part 22 of the second fermenter 20 in the tangential direction of the cross section of the second fermenter 20, the swirling downward flow is more effectively generated.

  Further, the inflow position of the lower inflow part 11 and the outflow position of the upper outflow part 12 of the first fermenter 10 are the circle radius from the center of the circle toward the tangential direction of the circle in the cross-sectional view of the first fermenter 10. It is preferably provided at a position not less than 0.5 times and less than 1.0 times the value, and more preferably not less than 0.6 times and not more than 0.75 times. Further, the inflow position of the upper inflow portion 21 and the outflow position of the intermediate outflow portion 22 of the second fermenter 20 are the circle radius from the center of the circle toward the tangential direction of the circle in the cross-sectional view of the second fermenter 20. It is preferably provided at a position not less than 0.5 times and less than 1.0 times the value, and more preferably not less than 0.6 times and not more than 0.75 times. As shown in FIG.1 (b), the inflow position of the lower inflow part 11 and the outflow position of the upper outflow part 12 are 0.5 times or more of a radius value toward the tangential direction from the cross-sectional center line of the 1st fermenter 10. It is provided in the position. Further, the inflow position of the upper inflow portion 21 and the outflow position of the intermediate outflow portion 22 of the second fermenter 20 are the circle radius from the center of the circle toward the tangential direction of the circle in the cross-sectional view of the second fermenter 20. It is provided at a position at least 0.5 times the value.

  Moreover, the position of the intermediate | middle outflow part 22 of the 2nd fermenter 20 is 0.1 or more and 0.5 or less distance from the said bottom part, when the distance from the bottom part of the said 2nd fermenter 20 to a liquid level is set to 1. It is preferable that the distance is 0.2 or more and 0.4 or less. As a result, a place where the swirl downward flow is weaker than the intermediate outflow portion 22 can be created, and the fermentation residue (sludge) can be further concentrated.

  Further, the second fermenter 20 has a recovery port portion 23 for recovering the fermentation residue below the intermediate outflow portion 22. The collection port 23 is connected to one end of the fermentation residue collection line 4 and collects the fermentation residue through the collection line 4 by the operation of the pump P3.

  Moreover, the raw material (biomass) of the to-be-fermented liquid can be supplied into the downstream of the pump P2 of the circulation part 2 by operation | movement of the pump P1 installed in the raw material supply line 1, and also pump P1 of the pump P1 and the circulation part 2 The raw material can be supplied along the circulation flow of the liquid to be fermented.

  Biogas (combustible gas) is generated from the upper portions of the first fermenter 10 and the second fermenter 20, and the biogas can be taken out from the respective pipes 5 and 6.

(Embodiment 2)
The fermentation processing apparatus of Embodiment 2 is demonstrated referring FIG. In the following, since the same configurations and reference numerals and the like as those of the first embodiment have the same functions, the description will be simplified or omitted, and different configurations will be mainly described. In FIG. 2, the residue circulation line 41 for supplying the fermentation residue collect | recovered from the collection port part 23 of the 2nd fermenter 20 to the 1st fermenter 10 is provided. The fermentation residue can be recovered, and the fermentation residue can be reintroduced into the first fermenter 10 by the pump P3 of the residue circulation line 41. One end of the residue circulation line 41 is connected to the recovery port portion 23, and the other end is connected to the downstream side of the pump P2 of the circulation portion 2, and the fermentation residue is supplied along the circulation flow of the liquid to be fermented.

(Embodiment 3)
The fermentation processing apparatus of Embodiment 3 is demonstrated referring FIG. In the following description, since the same configuration, reference numerals, and the like as those of the second embodiment have the same functions, the description will be simplified or omitted, and different configurations will be mainly described. In FIG. 3, a solid-liquid separation device 43 is provided in the residue circulation line 42. After the liquid and solid components in the fermentation residue are separated by the solid-liquid separator 43, the solid residue (moisture content is, for example, 75 to 97%) can be reintroduced into the first fermenter 10. The residue circulation line 42 has a path 421 for discharging the filtrate and a path 422 for returning the residue on the downstream side of the solid-liquid separator 43, and a pump P 4 is installed in the path 422 for returning the residue. Residue is sent downstream of P2.

(Embodiment 4)
The fermentation processing apparatus of Embodiment 4 is demonstrated referring FIG. In the following, since the same configurations and reference numerals and the like as those of the first embodiment have the same functions, the description will be simplified or omitted, and different configurations will be mainly described. In FIG. 4, the biogas produced | generated with the 1st fermenter 10 and the 2nd fermenter 20 is burned with the boiler 50, and a vapor | steam is generated. This steam is fed into the second fermenter 20 as a downward flow. Thereby, scum removal and heating (for fermentation promotion) can be performed simultaneously. The steam supply line 7 in FIG. 4 feeds steam by introducing piping into the second fermenter 20.

(Embodiment 5)
The fermentation processing apparatus of Embodiment 5 is demonstrated referring FIG. In the following, since the same configurations and reference numerals and the like as those of the first embodiment have the same functions, the description will be simplified or omitted, and different configurations will be mainly described. In FIG. 5, the biogas produced | generated with the 1st fermenter 10 and the 2nd fermenter 20 is burned with the boiler 50, and a vapor | steam is generated. This steam is used for heating the fermentation liquid in the first fermenter 10 (for fermentation promotion). The steam supply line 8 feeds steam so as to obtain a swirling upward flow 101 by introducing piping into the first fermenter 10. The inflow direction in which the steam flows from the steam supply line 8 to the first fermenter 10 is made to generate a swirling upward flow in the same manner as the inflow direction (configuration) of the lower inflow portion.

(Embodiment 6)
The fermentation processing apparatus of Embodiment 6 is demonstrated referring FIG. The sixth embodiment has each configuration of the first embodiment, and further includes a middle inflow portion 111. In the following, since the same configurations and reference numerals and the like as those of the first embodiment have the same functions, the description will be simplified or omitted, and different configurations will be mainly described. In FIG. 6, the first fermenter 10 is provided with a lower inflow portion 11 at the lower stage of the tank and a middle inflow portion 111 at the middle stage of the tank. The circulation part 2 (circulation line) is branched into two lines along the way, the first branch line L1 and the lower inflow part 11 are connected, and the second branch line L2 and the middle inflow part 111 are connected. The lower inflow portion 11 and the middle inflow portion 111 can accelerate the turning speed of the turning upward flow at the middle position, and can keep the turning speed of the turning upward flow from being attenuated.

  In the lower inflow portion 11 and the middle inflow portion 111 of the first fermenter 10, the inflow direction of the liquid to be fermented in each of the lower inflow portion 11 and the middle inflow portion 111 is directed to the central axis of the first fermenter 10 in a cross-sectional view. It is provided different from the direction. The inflow position of the lower inflow part 11 and the middle inflow part 111 and the outflow position of the upper outflow part 12 are 0 in the circular radius value from the center of the circle toward the tangential direction of the circle in the cross-sectional view of the first fermenter 10. It is preferably provided at a position not less than 5 times and less than 1.0 times, and more preferably provided at a position not less than 0.6 times and not more than 0.75 times. In FIG. 6, the direction of the lower inflow portion 11 and the direction of the middle inflow portion 111 overlap in the vertical position, but the present invention is not limited to this.

  Moreover, the position of the middle inflow part 111 of the 1st fermenter 10 is the 0.25-0.8, when the distance to a liquid level is set to 1 toward the liquid level from the bottom part of the 1st fermenter 10, More preferably, it is 0.4-0.75. Moreover, the ratio of the inflow amount in the lower inflow part 11 and the middle inflow part 111 is in the range of lower part: middle part = 25: 75 to 75:25.

(Embodiment 7)
The fermentation processing apparatus of Embodiment 7 is demonstrated referring FIG. The seventh embodiment has each configuration of the second embodiment, and further includes a middle inflow portion 111. As shown in FIG. 7, the first fermenter 10 is provided with a lower inflow portion 11 at the lower stage of the tank and a middle inflow portion 111 at the middle stage of the tank. The circulation part 2 (circulation line) to which the residue circulation line 41 is connected is branched into two lines along the way, the first branch line L1 and the lower inflow part 11 are connected, and the second branch line L2 and the middle inflow part 111 are connected. And are connected. The middle inflow portion 111 has the same configuration as that of the sixth embodiment.

(Embodiment 8)
The fermentation processing apparatus of Embodiment 8 is demonstrated referring FIG. The eighth embodiment has each configuration of the third embodiment, and further includes a middle inflow portion 111. As shown in FIG. 8, the first fermenter 10 is provided with a lower inflow portion 11 at the lower stage of the tank and a middle inflow portion 111 at the middle stage of the tank. The circulation part 2 (circulation line) to which the path 422 for returning the residue via the solid-liquid separator 43 is connected is branched into two lines along the way, the first branch line L1 and the lower inflow part 11 are connected, The two branch lines L2 and the middle inflow portion 111 are connected. The middle inflow portion 111 has the same configuration as that of the sixth embodiment.

(Embodiment 9)
A fermentation treatment apparatus according to Embodiment 9 will be described with reference to FIG. The ninth embodiment has each configuration of the fourth embodiment, and further includes a middle inflow portion 111. As shown in FIG. 9, the first fermenter 10 is provided with a lower inflow portion 11 at the lower stage of the tank and a middle inflow portion 111 at the middle stage of the tank. The circulation part 2 (circulation line) is branched into two lines along the way, the first branch line L1 and the lower inflow part 11 are connected, and the second branch line L2 and the middle inflow part 111 are connected. The middle inflow portion 111 has the same configuration as that of the sixth embodiment.

  Further, as in the fifth embodiment (FIG. 5), in the ninth embodiment as well, the steam supply line 8 for feeding the steam into the swirling upward flow 101 by introducing the pipe into the first fermentation tank 10 is provided. May be installed. The inflow direction in which the steam flows from the steam supply line 8 to the first fermenter 10 is made to generate a swirling upward flow in the same manner as the inflow direction (configuration) of the lower inflow portion.

(Embodiment 10)
The fermentation processing apparatus of Embodiment 10 is demonstrated referring FIG. The tenth embodiment has each configuration of the second embodiment, and further includes a middle inflow portion 111. As shown in FIG. 10, the first fermenter 10 is provided with a lower inflow portion 11 at the lower stage of the tank and a middle inflow portion 111 at the middle stage of the tank. The middle inflow part 111 and the residue circulation line 41 are directly connected, and the fermentation residue is configured to flow from the middle inflow part 111 into the first fermenter 10. The middle inflow portion 111 has the same configuration as that of the sixth embodiment.

(Embodiment 11)
The fermentation processing apparatus of Embodiment 11 is demonstrated referring FIG. The eleventh embodiment has each configuration of the third embodiment, and further includes a middle inflow portion 111. As shown in FIG. 11, the first fermenter 10 is provided with a lower inflow portion 11 at the lower stage of the tank and a middle inflow portion 111 at the middle stage of the tank. The middle inflow part 111 and the path 422 for returning the residue are directly connected, and the fermentation residue after the solid-liquid separation process is flowed from the middle inflow part 111 to the first fermenter 10. The middle inflow portion 111 has the same configuration as that of the sixth embodiment.

(Method of generating combustible gas)
Moreover, this invention is a method of producing a combustible gas by performing a fermentation process, circulating the to-be-fermented liquid between the 1st fermenter 10 and the 2nd fermenter 20. FIG. Any of Embodiments 1 to 11 of the fermentation treatment apparatus can be used.

  The present method includes a swirl upward flow forming step for forming a swirl upward flow 101 that moves the liquid to be fermented in the first fermenter 10 from the bottom to the top, and a second from the upper outflow portion 12 of the first fermenter 10. A swirl downward flow forming step for forming a swirl downward flow 201 of the liquid to be fermented from the top to the bottom by the flow of the liquid to be fermented of the swirl upward flow 101 flowing to the upper inflow portion 21 of the fermenter 20; The circulation step which circulates the to-be-fermented liquid from the intermediate | middle outflow part 22 of the 2 fermenter 20 to the lower inflow part 11 provided in the lower stage of the 1st fermenter 10, and a fermentation residue from the tank lower part of the 2nd fermenter 20 And a recovery step for recovering. Furthermore, you may include the residue circulation step which supplies the fermentation residue collect | recovered at the said collection | recovery step to the 1st fermenter 10. FIG. Moreover, you may further include the vapor | steam supply step which sends the vapor | steam obtained by burning the combustible gas produced in the 1st, 2nd fermenters 10 and 20 into the said 2nd fermenter 20. FIG. Moreover, the steam for heating which supplies the vapor | steam obtained by burning the combustible gas produced in the 1st, 2nd fermenters 10 and 20 to the said 1st fermenter 10 in order to heat a to-be-fermented liquid. A supply step may further be included.

  Furthermore, it is preferable to further include a second circulation step for supplying a circulation medium to the middle inflow portion 111 provided in the middle stage of the first fermenter 10 and above the lower inflow portion 11. This corresponds to the sixth to eleventh embodiments.

<Experimental example>
In the configuration of the fermentation treatment apparatus of Embodiments 1 and 6, a simulation experiment was performed on the swirling upward flow of the first fermentation tank. The first and second fermenters were 100 m ³ tanks having an inner diameter of 3.5 m and a water depth of 10.4 m (water depth / diameter = 2.97). The liquid to be circulated was water. Experimental Examples 1 and 2, in the configuration of Embodiment 1, is circulated amount which was set ^33m 3 / h, in ^{25 m} 3 / h, respectively. In Experimental Examples 3 to 7, in the configuration of the sixth embodiment, the circulation amount is set to 25 m ³ / h, the height position of the middle inflow portion 111 (distance from the bottom of the tank) is changed, and the lower inflow portion 11 and the middle portion The inflow amount of the inflow portion 111 is changed. The sum of the inflow amount from the lower inflow portion and the inflow amount from the middle inflow portion is the circulation amount. Table 1 shows the conditions and experimental results. The nozzle height position of the upper outflow portion 12 is 10.15 m, and the nozzle height position of the lower inflow portion 11 is 0.15 m. The flow velocity distribution (%) in each part is a distribution having a flow velocity of 0.1 m / sec or more (speed at which sludge does not settle at the bottom of the tank and speed at which scum moves at the tank surface) relative to the total cross-sectional area. Indicates the percentage. The speed in each cross section is calculated by simulation, distribution (speed contour map etc.) is obtained, and the above ratio is obtained. FIG. 12 shows a velocity contour map.

  From the comparison between Experimental Example 2 and Experimental Examples 3 to 7 (same circulation amount, presence / absence of divided inflow), it is more likely that the lower flow velocity and the lower flow area are divided into the lower flow area and the flow velocity distribution of 0.1 m / sec or more. The result was an increase (40.9% <43.4% to 58.3%). Moreover, even if a strong flow velocity is applied to the lower portion, the centrifugal force increases, so the area of 0.1 m / sec or more does not increase. However, by dividing the flow into the lower portion and the middle portion, the upper (surface layer) flow velocity distribution of 0. It was confirmed that the area of 1 m / sec or more increased (39.3% <48.0% to 62.7%).

  From the comparison between Experimental Example 1 and Experimental Examples 4 and 7 (decrease in circulation amount, presence / absence of divided inflow), even if the circulation amount is reduced, the lower flow rate distribution is 0.1 m / It was confirmed that the area of sec or more increased (55.0% <55.9%, 58.3%).

2 Circulation section 3 Piping 4 Fermentation residue collection line 10 First fermentation tank 11 Lower inflow section 12 Upper outflow section 20 Second fermentation tank 21 Upper inflow section 22 Intermediate outflow section 23 Recovery port 41 Fermentation residue circulation line 43 Solid-liquid separation Device 111 Middle inflow section L1 First branch line L2 Second branch line

Claims (17)

A first fermenter capable of forming a swirling upward flow of the liquid to be fermented from below to above,
The upper inflow part connected to the upper outflow part provided in the first fermenter has an upper inflow part, and the flow of the fermented liquid in the swirling upward flow that has flowed from the upper outflow part to the upper inflow part A second fermenter capable of forming a downward swirling flow of the liquid to be fermented downward;
The intermediate outflow part provided in the second fermenter is connected to the lower inflow part provided in the lower stage of the first fermenter, and the liquid to be fermented is supplied from the second fermenter to the first fermenter. A fermentation treatment apparatus comprising a circulation unit.   The fermentation treatment apparatus according to claim 1, wherein a middle inflow portion is further provided above the lower inflow portion in the middle stage of the first fermentation tank.   The fermentation processing apparatus according to claim 1, further comprising a raw material supply line in which a raw material supply pump unit for supplying the raw material of the liquid to be fermented to the downstream of the pump unit of the circulation unit is disposed. The lower fermenting portion and the upper outflow portion of the first fermenter are such that the inflow direction of the liquid to be fermented in the lower inflow portion and the outflow direction of the fermented liquid in the upper outflow portion are the first fermenter in cross-sectional view. It is provided to be different from the direction toward the center axis of
The upper inflow portion of the second fermenter is provided such that the inflow direction of the liquid to be fermented in the upper inflow portion is different from the direction toward the central axis of the second fermenter in a cross-sectional view. The fermentation treatment apparatus according to any one of 1 to 3.   The intermediate outflow portion of the second fermenter is provided such that the outflow direction of the liquid to be fermented in the intermediate outflow portion is different from the direction toward the central axis of the second fermenter in a cross-sectional view. 4. The fermentation treatment apparatus according to 4. The second fermentor has a recovery port for recovering fermentation residues below the intermediate outflow part,
The fermentation processing apparatus of any one of Claim 1 to 6 further equipped with the residue circulation line for supplying the fermentation residue collect | recovered from the said collection | recovery opening part of a said 2nd fermenter to a said 1st fermenter.   The fermentation treatment apparatus according to claim 6, wherein the residue circulation line includes a solid-liquid separator.   The vapor | steam supply line which sends the vapor | steam obtained by burning the combustible gas produced in the said 1st and 2nd fermenter into the said 2nd fermenter is further provided in any one of Claims 1-7. Fermentation processing equipment.   A heating steam supply line for supplying steam obtained by burning the combustible gas generated in the first and second fermenters to the first fermentor for heating the liquid to be fermented; The fermentation processing apparatus of any one of Claims 1-8 provided.   The fermentation treatment apparatus according to any one of claims 1 to 9, wherein the first and second fermenters are vertically long cylindrical shapes.   The fermentation treated in the first and second fermenters is hydrogen fermentation, methane fermentation, alcohol fermentation, lactic acid fermentation, butyric acid type fermentation, butanol-acetone type fermentation, nitrate fermentation or acetic acid fermentation. The fermentation treatment apparatus according to any one of claims. A method for producing a combustible gas by performing a fermentation process while circulating a liquid to be fermented between a first fermenter and a second fermenter,
A swirl upward flow forming step for forming a swirl upward flow from below to above the liquid to be fermented in the first fermentor;
A swirl downward flow of the liquid to be fermented from top to bottom is formed by the flow of the liquid to be fermented in the swirl upward flow that has flowed from the upper outflow part of the first fermenter to the upper inflow part of the second fermenter. A swirling downward flow forming step,
A circulation step of circulating the liquid to be fermented from the intermediate outflow part of the second fermenter to the lower inflow part provided in the lower stage of the first fermenter.   The method according to claim 12, further comprising a second circulation step of supplying a circulation medium to a middle inflow portion provided in a middle stage of the first fermenter and above the lower inflow portion.   The method according to claim 12, further comprising a raw material supply step of feeding the raw material of the liquid to be fermented to a downstream side of a circulation pump unit used in the circulation step. A recovery step of recovering the fermentation residue from the bottom of the second fermenter;
The method according to any one of claims 12 to 14, further comprising a residue circulation step of supplying the fermentation residue recovered in the recovery step to the first fermentor.   The vapor | steam supply step which sends the vapor | steam obtained by burning the combustible gas produced in the said 1st, 2nd fermenter into the said 2nd fermenter is further included in any one of Claims 12-15. the method of.   A heating steam supply step of supplying steam obtained by burning the combustible gas generated in the first and second fermenters to the first fermentor in order to heat the liquid to be fermented; 17. A method according to any one of claims 12 to 16, comprising.