JP7630459B2 - Biogas generation device, biomass power generation system, and biogas generation method - Google Patents

Description

This application relates to a biogas generation device, a biomass power generation system, and a biogas generation method.

In order to prevent global warming, efforts to utilize renewable energy sources such as solar, wind, geothermal, and biomass are accelerating. As part of these efforts, the combination of multiple renewable energy sources and their use as distributed power sources is being promoted. In distributed power sources, each renewable energy source is combined to compensate for each other's shortcomings in order to ensure a stable power supply, and individual renewable energy power generation facilities are managed according to the power demand of the supply destination. When biomass is used as a distributed power source, gas power generation is performed by burning biogas such as methane gas generated from organic matter (biomass power generation). The amount of power required for biomass power generation fluctuates from time to time, so in order to achieve a stable power supply, it is necessary to control the generation of biogas according to the amount of power required.

For example, anaerobic digestion is used to generate biogas for use in biomass power generation. Anaerobic digestion is a biological treatment method that uses anaerobic microorganisms to decompose organic matter, generating biogas as a decomposition product. One method for controlling the amount of biogas generated is to measure the internal conditions (pH, organic acid concentration) of the anaerobic digester into which organic waste (organic matter) is fed, as well as the actual amount of biogas generated, and control the amount of organic waste fed so that the biogas generation rate, etc., falls within a predetermined range (see, for example, Patent Document 1).

JP 2019-130486 A

Patent Document 1 discloses that it is desirable to adjust the biogas generation rate to a constant value while monitoring the amount of biogas generated with respect to the amount of organic waste input, and that when the biogas generation rate increases, the input amount is reduced to reduce the amount of biogas generated. However, in order to realize a stable power supply using biomass power generation as a distributed power source, it is necessary to generate a specific amount of biogas at a specific time according to the required amount of power generation. For example, it may be necessary to control the generation of a large amount of biogas in a specific time period and not generate biogas in other times. Controlling the generation of biogas by time in this way is not disclosed in Patent Document 1, and has not been considered in the past.
The present application discloses technology for solving the problems described above, and aims to provide a biogas generation device, a biomass power generation system, and a biogas generation method that are capable of generating a desired amount of biogas and generating biogas at a desired time period.

The biogas generation device disclosed in the present application is a biogas generation device in which generated biogas is used for power generation, and includes an anaerobic digestion section that subjects organic matter to anaerobic digestion treatment to generate biogas, an organic matter feeding section that feeds organic matter into the anaerobic digestion section in accordance with a feeding instruction that indicates the amount of organic matter to be fed at each time, a target value calculation section that calculates a target value for the biogas generation rate at each time based on a biogas generation command that includes a production amount condition related to the amount of biogas to be generated and a production period condition related to the period for generating biogas, and a control section that generates a feeding instruction based on the target value and causes the actual biogas generation rate at each time to become the target value , and terminates biogas generation by the start time of power generation .

The biogas generation method disclosed in the present application is a biogas generation device in which generated biogas is used for power generation, and includes the steps of receiving a biogas generation command including a generation amount condition related to the amount of biogas to be generated and a generation period condition related to the period for generating biogas, calculating a target value for the biogas generation rate at each time based on the biogas generation command, generating an instruction to input organic matter based on the target value, and inputting the organic matter into an anaerobic digestion section in accordance with the input instruction and subjecting the organic matter to anaerobic digestion treatment to generate biogas, and completes biogas generation by the start time of power generation .

The biogas generation device, biomass power generation system, and biogas generation method disclosed in the present application can simultaneously generate a desired amount of biogas and generate biogas at a desired time period.

FIG. 1 is a block diagram showing a configuration of a biogas generation device in a first embodiment. 3 is a block diagram showing a configuration of a control unit according to the first embodiment; FIG. 4 is a block diagram showing a configuration of a target value calculation unit according to the first embodiment; FIG. FIG. 1 is a diagram showing the relationship between the amount of power generation, the amount of organic matter input, and the biogas generation rate when generating biogas required for biomass power generation that generates a constant amount of electricity for a long period of time in the biogas generation device of embodiment 1. FIG. 1 is a diagram showing the relationship between the amount of power generation, the amount of organic matter input, and the biogas generation rate when generating biogas required for biomass power generation that generates high-output electricity for a short period of time in the biogas generation device of embodiment 1. FIG. 2 is a diagram illustrating an example of a hardware configuration for implementing a control unit of a biogas generation apparatus in the first embodiment. FIG. 2 is a flow diagram showing the operation of the biogas generation device in the first embodiment. FIG. 11 is a flow chart showing the operation of the biogas generation device of the first embodiment when there is a difference between the actual biogas generation rate and a target value. FIG. 11 is a block diagram showing the configuration of a biomass power generation system in a second embodiment. FIG. 11 is a block diagram showing a configuration of a supply and demand balance control device according to a second embodiment.

Embodiment 1.
A first embodiment will be described below with reference to FIG. 1. FIG. 1 is a block diagram showing the configuration of a biogas generator in the first embodiment. The biogas generator 100 includes an anaerobic digestion tank 1 that generates biogas such as methane gas from organic matter, i.e., an anaerobic digestion section, an organic matter input section 2 that inputs organic matter C into the anaerobic digestion tank 1, a biogas pipe 3 that is connected at one end to the anaerobic digestion tank 1 and transports the biogas generated in the anaerobic digestion tank 1, i.e., a biogas transport section, a biogas flow rate measuring section 4 that is provided in the biogas pipe 3 and measures the amount of biogas flowing through the biogas pipe 3 (biogas flow rate), and a biogas tank 5 that is connected at the other end of the biogas pipe 3 and stores the biogas transported from the anaerobic digestion tank 1, i.e., a biogas storage section. The organic matter input section 2 and the biogas flow rate measuring section 4 are connected to a control section 7 via signal lines 6a and 6b, respectively. The control section 7 is connected to a target value calculation section 8 via a signal line 6c. The signal lines 6a, 6b, and 6c are wired or wireless signal lines.

Anaerobic digestion tank 1 stores digested sludge containing multiple types of anaerobic microorganisms (not shown), and multiple decomposition processes are carried out in a chain reaction by each type of anaerobic microorganism. First, acid-producing bacteria decompose organic matter C to produce low molecular weight organic acids such as propionic acid, butyric acid, and acetic acid. Next, methanogens decompose the low molecular weight organic acids to produce biogas containing methane gas.

In addition, since the activity of methanogens in the anaerobic digestion tank 1 is affected by temperature and pH, a temperature adjustment means such as a heater (not shown) or a pH adjustment means (not shown) equipped with an acid/alkali solution delivery pump may be provided in the anaerobic digestion tank 1 to adjust the environment within the anaerobic digestion tank 1 to one suitable for the activity of the methanogens.

The organic matter injection unit 2 injects organic matter C into the anaerobic digestion tank 1 in accordance with an injection instruction signal S1 from the control unit 7. The injection instruction signal S1 includes injection count information indicating the number of times organic matter C is injected (e.g., the number of times per day), injection time information indicating the time of injection, and injection amount information indicating the amount of organic matter C injected at each time (or the amount injected per unit time), and is transmitted from the control unit 7 to the organic matter injection unit 2 via the signal line 6a. The organic matter injection unit 2 may be any device capable of injecting organic matter C into the anaerobic digestion tank 1. For example, when organic matter C is organic matter contained in organic sludge, the organic matter injection unit 2 is composed of an organic matter injection device including a pipe for transporting organic sludge and a pump for sending the organic sludge.

It is also possible to provide multiple organic matter input units 2, with each organic matter input unit 2 inputting a different type of organic matter. In this case, a signal line 6a is also provided corresponding to each organic matter input unit 2. The control unit 7 generates an input instruction signal S1 corresponding to each organic matter input unit 2, and controls each organic matter input unit 2 individually.

The biogas generated in the anaerobic digester 1 flows out into the biogas piping 3. The flow rate of the biogas that flows out into the biogas piping 3 is measured by the biogas flow rate measuring unit 4, and then the biogas flows further through the biogas piping 3 into the biogas tank 5. The biogas that flows into the biogas tank 5 is stored in the biogas tank 5 until it is used in a power generation device (not shown in FIG. 1) or the like.

The biogas flow rate measuring unit 4 constantly or intermittently measures the flow rate of the biogas flowing through the biogas piping (biogas flow rate), and is composed of a dry or wet gas flow meter or the like. The biogas flow rate measuring unit 4 transmits a biogas flow rate signal S2 indicating the measurement result of the biogas flow rate to the control unit 7 via the signal line 6b. The biogas flow rate measured by the biogas flow rate measuring unit 4 indicates the generation rate of the biogas generated in the anaerobic digestion tank 1. In other words, the measurement of the biogas flow rate by the biogas flow rate measuring unit 4 also measures the biogas generation rate, and the biogas flow rate measuring unit 4 corresponds to a biogas generation rate measuring unit.

The control unit 7 will be described. FIG. 2 is a block diagram showing the configuration of the control unit according to the first embodiment. The control unit 7 includes an input unit 71 that accepts input of various signals, an input plan generation unit 72 that generates an input plan for organic matter C, an input instruction generation unit 73 that generates an input instruction signal S1 based on the input plan, a comparison unit 74 that compares the actual value of the biogas generation rate with a target value, an input instruction correction unit 75 that generates a signal for correcting the input instruction for organic matter C when there is a difference between the actual value of the biogas generation rate and the target value, and an output unit 76 that outputs various signals.

The control unit 7 controls the organic matter input unit 2 so that the actual biogas generation rate becomes the target value at each time. The control unit 7 receives a target value signal S3 indicating the target value of the biogas generation rate at each time from the target value calculation unit 8. The target value signal S3 is transmitted from the target value calculation unit 8 to the control unit 7 via the signal line 6c and is accepted by the input unit 71.

The control unit 7 generates an input instruction signal S1 so that the actual biogas generation rate at each time becomes the target value indicated by the target value signal S3. The input plan generation unit 72 generates an input plan including the number of inputs of organic matter C (e.g., the number of inputs per day), the input time, and the input amount of organic matter C at each time (or the input amount per unit time) based on the target value signal S3. The input instruction generation unit 73 generates an input instruction signal S1 indicating the input amount of organic matter C at each time (or the input amount per unit time) based on the input plan. The generated input instruction signal S1 is transmitted to the organic matter input unit 2 by the output unit 76.

Since a certain amount of time is required for the decomposition of organic matter C by anaerobic microorganisms, it takes a certain amount of time from when the organic matter input unit 2 inputs the organic matter C into the anaerobic digester 1 until biogas is generated. Also, since biogas is generated gradually, the biogas generation rate after biogas generation starts also changes with time. For example, when organic matter C is input once, the biogas generation rate increases with time after biogas generation starts, and after the biogas generation rate peaks, the biogas generation rate decreases and finally becomes zero, and biogas generation ends. The total (or integral) of the generation rate from the start to the end of biogas generation is the amount of biogas generated by one input. The input plan generation unit 72 generates an input plan for organic matter C while using parameters that indicate the decomposition characteristics of organic matter C.

When organic matter C is added multiple times a day, the biogas generation rate at each time is the sum of the biogas generation rates resulting from each addition. Therefore, by adjusting the number of times organic matter C is added to the anaerobic digester 1 per day, and the time and amount of each addition, it is possible to adjust the biogas generation rate at each time, and also the amount of biogas generated per day.

The control unit 7 receives the biogas flow rate signal S2 from the biogas flow rate measurement unit 4, and uses the comparison unit 74 to compare the biogas flow rate (indicating the actual biogas generation rate) indicated by the biogas flow rate signal S2 with the target value indicated by the target value signal S3. If there is a difference between the two, the input instruction correction unit 75 corrects the input instruction so that the actual biogas generation rate matches the target value. Specifically, an additional input instruction signal S1 is sent to the organic matter input unit 2 to increase the input amount of organic matter C, or a signal (not shown) for correcting the input instruction signal S1 that has already been sent is sent to the organic matter input unit 2 to correct the input amount of organic matter C, etc. Such a signal for correcting the input instruction is generated by the input instruction correction unit 75. By incorporating the above-mentioned correction into the control, the difference between the biogas generation rate of the biogas generated from the anaerobic digester 1 and the above-mentioned target value can be brought close to zero.

The target value calculation unit 8 will be described. FIG. 3 is a block diagram showing the configuration of the target value calculation unit according to the first embodiment. The target value calculation unit 8 includes an input unit 81 that accepts input of various signals, a biogas generation target generation unit 82 that generates a biogas generation target, a generation rate target value calculation unit 83 that calculates a target value for the biogas generation rate at each time and generates a target value signal S3, and an output unit 84 that outputs various signals.

The target value calculation unit 8 receives a biogas generation command signal S from the outside through the input unit 81, and generates a biogas generation target including the amount of biogas to be generated, the generation start time, the generation end time, etc. from the information included in the biogas generation command signal S through the biogas generation target generation unit 82. The generation rate target value calculation unit 83 calculates the target value of the biogas generation rate at each time based on the biogas generation target, and generates a target value signal S3. The output unit 84 inputs the target value signal S3 to the control unit 7 through the signal line 6c. The biogas generation command indicated by the biogas generation command signal S includes a generation amount condition regarding the amount of biogas to be generated and a generation period condition regarding the period or time zone for generating biogas. When it is assumed that biogas is generated for biomass power generation, the generation amount condition is determined by the power generation amount of the power generation device that performs biomass power generation, and the generation period condition is determined by the power generation period (power generation start time and power generation end time).

Although not shown in the figure, a configuration may be added in which the amount of biogas stored in the biogas tank 5 is measured and transmitted to the target value calculation unit 8, and the target value for the biogas generation rate at each time point is calculated by correcting the target value based on the amount of storage.

The configurations of the functional units shown in Figs. 2 and 3 are merely examples. In the first embodiment, any configuration that can generate the input instruction signal S1 from the biogas generation command signal S may be used, and therefore some or all of the functions of the target value calculation unit 8 shown in Fig. 3 may be functions of the control unit 7.

The input instruction for organic matter C is generated based on the initial input plan, and this input plan is based on the target value signal S3 from the target value calculation unit 8. If the actual input situation of organic matter C (such as the input amount and input time) differs from the initial plan due to a correction of the input instruction, the biogas generation target may also need to be revised. In addition, it takes a certain amount of time for the correction of the input instruction to be reflected as a correction of the biogas generation rate. For this reason, when the input instruction for organic matter C is corrected, the control unit 7 may evaluate the effect of the correction on the generation of biogas and notify the target value calculation unit 8 as necessary. Upon receiving the notification, the target value calculation unit 8 updates the biogas generation target as necessary and recalculates the target value of the biogas generation rate at each time.

Regarding the correction of the input instruction for organic matter C, the biogas flow rate signal S2 may be sent to the target value calculation unit 8, which may compare the actual biogas generation rate with the target value. If there is a difference between the two, the target value calculation unit 8 evaluates the difference, updates the biogas generation target as necessary, and recalculates the target value of the biogas generation rate at each time. The target value calculation unit 8 generates a new target value signal S3 based on the result of the recalculation, and sends it to the control unit 7. The control unit 7 corrects the input instruction based on the new target value signal S3.

The generation of the input instruction signal S1 from the biogas generation command signal S will be further described. Here, assuming that the generated biogas is used for biomass power generation, a case where a constant amount of power is generated for a long time by biomass power generation and a case where high-output power is generated for a short time will be described. FIG. 4A is a diagram showing the relationship between the amount of power generated, the amount of organic matter input, and the biogas generation rate when generating biogas required for biomass power generation that generates a constant amount of power for a long time in the biogas generation device of embodiment 1, and FIG. 4B is a diagram showing the relationship between the amount of power generated, the amount of organic matter input, and the biogas generation rate when generating biogas required for biomass power generation that generates high-output power for a short time. In FIGS. 4A and 4B, the horizontal axis represents time, and the vertical axis represents the amount of power generated, the amount of organic matter input, and the biogas generation rate. In addition, in FIGS. 4A and 4B, the "amount of power generated" is the "amount of power generated per unit time". In addition, the "amount of organic matter input" is the "amount of organic matter input per unit time". When a constant amount of electricity is generated for a long period of time, as shown in FIG. 4A, the amount of organic matter input and the rate of biogas generation are also constant for a constant amount of electricity generated. In this case, the amount of biogas stored in the biogas tank 5 is also kept constant.

A case where high-output electricity is generated for a short time will be described. In FIG. 4B, time t1 indicates the start time of power generation, time t2 indicates the end time of power generation, time t3 indicates the start time of organic matter C input, and time t4 indicates the end time of organic matter C input. Time t5 indicates the start time of biogas generation, and time t6 indicates the end time of biogas generation. In this case, the area of X in the figure indicates the total amount of power generation, and the area of Y indicates the total amount of organic matter C input. Also, the area of Z indicates the total amount of biogas generated. In other words, the example of FIG. 4B shows that for an organic matter input amount of Y, there is an amount of biogas generated of Z, which results in an amount of power generation of X. It takes time from input of organic matter C to the generation of biogas, so t3<t5.

When considering the efficiency of biomass power generation, it is desirable that biogas generation has finished before power generation begins. In other words, it is desirable that t6 < t1 be true. This is because if biogas generation continues after power generation has started or ended, surplus biogas will be generated. If surplus biogas accumulates, it will be necessary to dispose of the surplus biogas by burning it or other means in order to maintain a stable power supply, which will reduce the efficiency of biomass power generation. Note that while the example shown in Figure 4B assumes that organic matter is added once, it is also possible that organic matter is added multiple times. In such a case, adjustments are made to start power generation after biogas generation from the last organic matter C added has finished.

As described above, the biogas generation command indicated by the biogas generation command signal S input to the target value calculation unit 8 includes a generation amount condition related to the amount of biogas to be generated and a generation period condition related to the period or time period during which biogas is generated. In the example shown in FIG. 4B, the generation amount condition is determined by the power generation amount (X in FIG. 4B) of the power generation device that performs biomass power generation, and the generation period condition is determined by the power generation period (power generation start time and power generation end time, i.e., t1 and t2 in FIG. 4B). Therefore, the target value calculation unit 8 generates a biogas generation target including the biogas generation amount (Z in FIG. 4B) and generation period (generation start time and generation end time, i.e., t5 and t6 in FIG. 4B) based on the power generation amount and power generation period of biomass power generation, calculates the target value of the biogas generation rate at each time based on the biogas generation target, generates a target value signal S3, and transmits the target value signal S3 to the control unit 7.

The control unit 7 to which the target value signal S3 is input generates an input plan including the input time (input start time and input end time, i.e., t3 and t4 in FIG. 4B) and input amount (Z in FIG. 4B) of the organic matter C based on the target value signal S3, calculates the input amount of the organic matter C at each time based on the input plan, generates an input instruction signal S1, and transmits it to the organic matter input unit 2. The organic matter input unit 2 that receives the input instruction signal S1 inputs the organic matter C into the anaerobic digestion tank 1 according to the input instruction signal S1. By generating the input instruction signal S1 in the above manner, it is possible to generate an input instruction for the organic matter C so as to generate the amount of biogas required for biomass power generation while terminating the generation of biogas before the start of power generation of biomass power generation. In other words, it is possible to generate a desired amount of biogas and generate biogas at a desired time period.

After the organic matter feeding unit 2 starts feeding the organic matter C, the control unit 7 periodically receives the biogas flow rate signal S2 from the biogas flow rate measurement unit 4 and monitors whether there is any difference between the actual biogas generation rate and the target value. If there is a difference, the feeding instruction is corrected as described above to adjust the actual biogas generation rate to approach the target value. The presence or absence of the difference may be determined not only by whether the actual biogas generation rate and the target value completely match, but also by whether the difference between the actual biogas generation rate and the target value is smaller than a predetermined threshold value.

In the first embodiment, as an example, it is assumed that the transition of the biogas generation rate forms an isosceles triangle, and the input amount of organic matter C is controlled. It is generally known that the amount of biogas generated by the decomposition of 1 g of organic matter is about 1 L, and it is also known that in the case of organic matter C, which is easily decomposed, the decomposition is completed in about 1 hour (60 min). In this case, the period between time t5 and time t6 is 60 min, and the area of Z is 1 L. The biogas generation rate increases from 0 L/min in proportion to the time, reaches a peak (0.033 L/min) at the time ((t5 + t6)/2), and then decreases in proportion to the time to reach 0 L/min at time t6, i.e., the generation of biogas ends.

If the amount of organic matter C added is M (g) and the time required for decomposition remains at 1 hour, the transition of the biogas generation rate describes an isosceles triangle with a peak at 0.033×M (L/min). As described above, the control unit 7 controls the biogas generation rate between 0 and 0.033×M (L/min). In other words, the input of organic matter C is controlled so that the biogas generation rate F(t) at time t satisfies the following formulas (1) to (3).

F(t)=0 (t<t5)...(1)
0≦F(t)≦0.033×M (t5≦t≦t6)...(2)
F(t)=0 (t>t6)...(3)

In addition, when the change in the biogas generation rate forms an isosceles triangle as in the example shown in FIG. 4B, F(t) at (t5≦t≦t6) is expressed by the following equations (4) and (5).

F(t)=(2×0.033×M)/(t6-t5)×(t-t5)
(t5≦t≦((t5+t6)/2)...(4)
F(t)=(2×0.033×M)/(t6-t5)×(-t+t6)
(((t5+t6)/2)<t≦t6)...(5)

Incidentally, since an excessive amount of organic matter C fed into the anaerobic digestion tank 1 may hinder the decomposition of the organic matter C, it is preferable to set an upper limit on the amount of organic matter C fed per day. This upper limit is determined by the volume of digested sludge stored in the anaerobic digestion tank 1. In other words, it is preferable to set the amount of organic matter C fed into the anaerobic digestion tank 1 per day to 3 kg or less per ¹ m3 of digested sludge (3 kg/ ^m3 /day).

Next, the hardware configuration for implementing each functional unit of the biogas generating device 100 will be described. FIG. 5 is a diagram showing an example of a hardware configuration for implementing each functional unit of the control unit according to the first embodiment. FIG. 5 shows the hardware configuration of the control unit 7, but the same is true for the target value calculation unit 8. The control unit 7 is mainly composed of a processor 91, a memory 92 as a main storage device, and an auxiliary storage device 93. The processor 91 is composed of, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc.

The memory 92 is composed of a volatile storage device such as a random access memory, and the auxiliary storage device 93 is composed of a non-volatile storage device such as a flash memory or a hard disk. A predetermined program executed by the processor 91 is stored in the auxiliary storage device 93, and the processor 91 reads and executes this program as appropriate to perform various arithmetic processing. At this time, the predetermined program is temporarily saved from the auxiliary storage device 93 to the memory 92, and the processor 91 reads the program from the memory 92. The various arithmetic processing of the control unit 7 according to the first embodiment is realized by the processor 91 executing the predetermined program as described above. The results of the arithmetic processing by the processor 91 are temporarily stored in the memory 92, and are then stored in the auxiliary storage device 93 according to the purpose of the executed arithmetic processing.

The control unit 7 also includes a receiver 94 that receives signals from the target value calculation unit 8 and the biogas flow measurement unit 4, etc., and a transmitter 95 that transmits signals to the organic matter injection unit 2, etc.

Next, the operation will be described. FIG. 6 is a flow diagram showing the operation of the biogas generation device in embodiment 1. First, a biogas generation command signal S is received (step ST001). Next, a biogas generation target including the amount of biogas to be generated and the generation period is generated (step ST002).

Next, the target value of the biogas generation rate at each time is calculated based on the biogas generation target generated in step ST002 (step ST003).

Next, an instruction to input organic matter C is generated so as to achieve the target value of the biogas generation rate at each time calculated in step ST003 (step ST004). In generating this input instruction, first, an input plan including the input time (input start time and input end time) and input amount of organic matter C is generated based on the target value of the biogas generation rate at each time, and an instruction to input organic matter C is generated based on this input plan. The instruction to input organic matter C is based on the biogas generation target generated in step ST002.

Next, organic matter C is added to the anaerobic digestion tank 1 in accordance with the organic matter input instruction generated in step ST004 (step ST005). The organic matter C added to the anaerobic digestion tank 1 is subjected to anaerobic digestion treatment, generating biogas.

Next, the operation related to the correction of the organic matter input instruction will be described. Figure 7 is a flow diagram showing the operation when there is a difference between the actual biogas generation rate and the target value in the biogas generation device of embodiment 1. Figure 7 shows the operation during input of organic matter C after input of organic matter C has already started. First, the actual biogas generation rate is measured (step ST101).

Next, the actual biogas generation rate measured in step ST101 is compared with the target value for the biogas generation rate at that time, and it is determined whether there is a difference between the two (step ST102). If it is determined that there is a difference between the two, the process proceeds to step ST103, and if it is determined that there is no difference, the process ends.

If it is determined in step ST102 that there is a difference, it is determined that biogas is not being generated as targeted, and the organic matter input instruction is corrected (step ST103). Specifically, an additional input instruction is generated to increase the input amount of organic matter C, and a correction is made to make the actual biogas generation rate match the target value.

If the organic matter input instruction is corrected in step ST103, the biogas generation target is modified as necessary, and the target value of the biogas generation rate at each time is recalculated (step ST104).

The operations shown in FIG. 7 are performed periodically while biogas is being generated. Furthermore, if the operations of steps ST101 and ST102 are performed after the end time of the biogas generation target, it is possible to detect that biogas is being generated even when biogas should not be generated, i.e., when the target value for the biogas generation rate is zero, and to detect an abnormality related to the generation of biogas.

According to the first embodiment, it is possible to generate a desired amount of biogas and generate biogas in a desired time period. More specifically, the apparatus includes a target value calculation unit that calculates a target value of the biogas generation rate at each time based on a biogas generation command signal including a generation amount condition related to the amount of biogas to be generated and a generation period condition related to the period during which biogas is generated, and a control unit that generates an input instruction signal based on the target value, and the input of organic matter into the anaerobic digester is performed according to the input instruction. The actual generation rate of biogas at each time is controlled to be the target value, and the target value is calculated based on the biogas generation amount condition and the biogas generation period condition. Therefore, by setting the generation amount condition and the generation period condition so that the desired amount of biogas is generated in the desired time period, it is possible to generate a desired amount of biogas and generate biogas in the desired time period.

In addition, the actual biogas generation rate can be brought closer to the target value more reliably. More specifically, a biogas flow rate measuring unit 4 is further provided which measures the actual biogas generation rate and transmits the measurement result to the control unit, and if there is a difference between the actual biogas generation rate and the target value, the instruction to feed the organic matter is corrected so that this difference approaches zero. As a result, even if the actual biogas generation rate deviates from the target value during the feeding of the organic matter, the deviation can be eliminated, and the actual biogas generation rate can be brought closer to the target value more reliably.

Embodiment 2.
Next, a second embodiment will be described with reference to Figs. 8 and 9. Fig. 8 is a block diagram showing the configuration of a biomass power generation system in the second embodiment. In Fig. 8, components that are the same as or correspond to those in the first embodiment are given the same reference numerals. The biomass power generation system 1000 is obtained by adding a power generation device 9 to the biogas generation device 100 described in the first embodiment. The power generation device 9 is connected to the biogas tank 5 by a biogas piping 31, and generates power using the biogas stored in the biogas tank 5. The power generation device 9 is connected to a supply and demand balance control device 11 by a power transmission line 10. The supply and demand balance control device 11 is also connected to an electricity demand area 12 by the power transmission line 10. The supply and demand balance control device 11 is also connected to the power generation device 9 and the target value calculation unit 8 by a signal line 6d and a signal line 6e.

The biomass power generation system 1000 is used as one of the power sources that make up a distributed power source. In an actual distributed power source, other power sources such as solar, wind, and hydraulic power are also combined to make up a distributed power source, but in FIG. 8, power sources other than biomass power generation are omitted. When the biogas generated by the biogas generation device 100 is used as an energy source for the biomass power generation system 1000, the biogas stored in the biogas tank 5 is sent to the power generation device 9 through the biogas piping 31. The power generation device 9 performs biomass power generation by burning the sent biogas. A plurality of power generation devices 9 are installed, and the more the number of devices used for power generation is increased, the higher the generated power can be generated. The generated power by the power generation device 9 is supplied to the power demand area 12 through the power transmission line 10. At this time, the supply and demand balance control device 11 records the operation history including the power generation amount and power generation period of the power generation device 9 based on the amount of power supplied from the power generation device 9 to the power demand area 12.

The supply and demand balance control device 11 will now be described. FIG. 9 is a block diagram showing the configuration of the supply and demand balance control device according to the second embodiment. The supply and demand balance control device 11 includes an input unit 111 that accepts input of various signals, an operation history storage unit 112 that stores the operation history of the power generation device 9, a power generation plan generation unit 113 that generates a power generation plan for the power generation device 9, and an output unit 114 that outputs various signals. Note that the hardware configuration that realizes each functional unit of the supply and demand balance control device 11 is the same as that shown in FIG. 5, and therefore description thereof will be omitted.

The supply and demand balance control device 11 controls the supply and demand balance between the distributed power sources including the biomass power generation system 1000 and the power demand area 12. It measures the power demand in the power demand area 12 and generates a power generation plan for the power generation device 9 by the power generation plan generation unit 113. The power generation plan generation unit 113 first predicts the amount of power that the power generation device 9 should generate and the power generation period by calculating the supply and demand balance based on the power demand in the power demand area 12. In making this prediction, the operation history of the power generation device 9 can be incorporated into the calculation to predict the optimal value of the amount of power that the power generation device 9 should generate. In addition, the power generation status (power generation amount at each time) of power sources other than the biomass power generation system 1000 may be incorporated into the above calculation. This makes it possible to formulate a power supply plan such as "photovoltaic power generation during the day and biomass power generation at night", and to predict the amount of power generation and power generation period that the biomass power generation (power generation device 9) should generate based on the time period when the power supply from other power sources decreases and the amount of decrease. In this case, a more stable power supply can be achieved. Based on the above prediction, the power generation plan generation unit 113 generates a power generation plan including the amount of power generated by the power generation device 9 and the power generation period (power generation start time and power generation end time).

The supply and demand balance control device 11, which has generated the power generation plan, transmits a power generation request signal S4 to the power generation device 9 via the signal line 6d. The power generation request signal S4 is generated based on the power generation plan and includes information indicating the amount of power generation that the power generation device 9 should generate and information indicating the power generation period. Upon receiving the power generation request signal S4, the power generation device 9 generates power in accordance with the information indicated by the power generation request signal S4.

The supply and demand balance control device 11 transmits the power generation information signal S5 to the target value calculation unit 8 of the biogas generation device 100 via the signal line 6e. The power generation information signal S5 is generated based on the above power generation plan and includes the same information as the power generation request signal S4, i.e., information indicating the amount of power generation to be generated by the power generation device 9 and information indicating the power generation period. The power generation information signal S5 received by the target value calculation unit 8 is treated in the same manner as the biogas generation command signal S described in the first embodiment. That is, the target value calculation unit 8 that receives the power generation information signal S5 generates a target value signal S3 based on the amount of power generation and the power generation period indicated by the power generation information signal S5, and transmits the target value signal S3 to the control unit 7. The control unit 7 that receives the target value signal S3 generates an input instruction signal S1 based on the target value of the biogas generation rate at each time included in the target value signal S3. The control unit 7 transmits the generated input instruction signal S1 to the organic matter input unit 2. The organic matter input unit 2 inputs organic matter C according to the input instruction signal S1. The specific flow from the power generation information signal S5 to the generation of the input instruction signal S1 is the same as in embodiment 1.

The target value calculation unit 8 only needs to transmit a signal that can function as a biogas generation command signal S, i.e., a signal that includes information that can determine the biogas generation amount and generation period conditions. For example, the target value calculation unit 8 may be configured to transmit information about the power demand in the power demand area 12, the operation history of the power generation device 9, and information about the power generation status of other power sources. In this case, the amount of power that the power generation device 9 should generate and the power generation period are calculated in the target value calculation unit 8.

According to the second embodiment, the same effect as the first embodiment can be obtained, and a stable power supply can be realized through biomass power generation.

Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.
Therefore, countless modifications not illustrated are conceivable within the scope of the technology disclosed in the present application, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

1 Anaerobic digestion tank, 2 Organic matter input section, 3, 31 Biogas piping, 4 Biogas flow rate measurement section, 5 Biogas tank, 7 Control section, 8 Target value calculation section, 9 Power generation device, 11 Supply and demand balance control device, 12 Electricity demand area, 72 Input plan generation section, 73 Input instruction generation section, 74 Comparison section, 75 Input instruction correction section, 82 Biogas generation target generation section, 83 Generation rate target value calculation section, 100 Biogas generation device, 113 Power generation plan generation section, 1000 Biomass power generation system, S Biogas generation command signal, S1 Input instruction signal, S2 Biogas flow rate signal, S3 Target value signal, S4 Power generation request signal, S5 Power generation information signal

Claims (8)

A biogas generating apparatus in which the generated biogas is used for power generation,
an anaerobic digestion unit that performs anaerobic digestion treatment on organic matter to generate the biogas;
an organic matter input unit that inputs the organic matter into the anaerobic digestion unit in accordance with an input instruction that indicates an input amount of the organic matter at each time;
a target value calculation unit that calculates a target value of the generation rate of the biogas at each time based on a biogas generation command including a generation amount condition related to the amount of the biogas to be generated and a generation period condition related to a period during which the biogas is generated;
a control unit that generates the input instruction based on the target value and causes the actual generation rate of the biogas at each time to match the target value ;
A biogas generating device characterized in that the generation of the biogas is completed by the start time of the power generation . The biogas generation device according to claim 1, wherein when the organic matter is added multiple times, generation of the biogas produced by the last added organic matter is terminated by the start time of the power generation. A biogas generation rate measuring unit is further provided for measuring an actual generation rate of the biogas and transmitting the measurement result of the actual generation rate to the control unit,
The biogas generation device according to claim 1 or 2, wherein the control unit compares the actual biogas generation rate with the target value, and if there is a difference between the actual biogas generation rate and the target value, corrects the input instruction to bring the difference closer to zero. The biogas generation apparatus according to any one of claims 1 to 3, further comprising a biogas storage unit that stores the biogas, and a biogas transport unit that transports the biogas from the anaerobic digestion unit to the biogas storage unit. A biomass power generation system constituting a distributed power source that supplies power to an area of power demand,
The biogas generating apparatus according to claim 4 ,
a power generation device that generates electricity using the biogas supplied from the biogas generation device and supplies the electricity obtained by the power generation to the electricity demand area,
A biogas production command for causing the biogas production device to produce the biogas is
A condition regarding the amount of the biogas to be generated, the condition being determined based on the amount of power generated by the power generation device;
and a generation period condition, which is determined based on a power generation period of power generation by the power generation device. an amount of power generated by the power generation device is controlled by a supply and demand balance control device that controls a supply and demand balance between the distributed power source and the power demand area;
The biomass power generation system of claim 5, wherein the supply and demand balance control device predicts the power generation amount and the power generation period based on the supply and demand balance, and the generation amount condition and the generation period condition are determined based on the power generation amount and the power generation period predicted by the supply and demand balance control device , respectively. A method for producing biogas, in which the produced biogas is used for power generation, comprising:
receiving a biogas production command including a production amount condition regarding an amount of the biogas to be produced and a production period condition regarding a period during which the biogas is to be produced;
calculating a target value of the biogas generation rate at each time based on the biogas generation command;
generating an organic matter input instruction based on the target value;
and feeding the organic matter into an anaerobic digestion section in accordance with the feeding instruction and subjecting the organic matter to anaerobic digestion treatment to generate biogas .
A biogas generation method, comprising completing the generation of the biogas by the start time of the power generation . The biogas production method according to claim 7, wherein, when the organic matter is added multiple times, generation of the biogas produced by the last added organic matter is terminated by the start time of the power generation.

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