Biogas power generation system

Abstract

To provide a biogas power generating system which is excellent in power generating efficiency.SOLUTION: A biogas power generating system 1 includes a biogas generating tank 22, a biogas storing tank 23, a biogas power generator 31, a power transmission system 32, a temperature adjusting part 41, a gas pressure detection part 42, a failure detection part 43, and a control unit 44. When the failure detection part 43 detects failure of the power transmission system 32, the control unit 44 determines whether a biogas generated amount needs to be reduced according to detection of the gas pressure detection part 42. When it is determined that the biogas generated amount needs to be reduced, the control unit 44 predicts a recovery predicted time of the power transmission system 32, according to the degree of the failure of the power transmission system 32 detected by the failure detection part 43. The control unit 44 adjusts the temperature of the biogas generating tank 22 by control of the temperature adjusting part 41, and reduces the biogas generated amount according to the recovery predicted time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a biogas power generation system including a biogas generator. [Background technology]

[0002] In recent years, biogas power generation systems have been attracting attention. A biogas power generation system includes a gas storage unit that stores biogas and a biogas generator that burns (consumes) the biogas to generate electricity.

[0003] Biogas is produced by methane fermentation of organic waste, such as food waste, sewage, livestock manure, and food waste. The biogas is first supplied to a gas storage unit and temporarily stored there. The biogas is then supplied from the gas storage unit to a biogas generator. The biogas generator burns the biogas to generate electrical energy, which is then supplied to a known electric device and / or battery via a power transmission system. Such a biogas power generation system is carbon-neutral and environmentally friendly.

[0004] On the other hand, in a biogas power generation system, a breakdown in the power transmission system may cause a decrease in the amount of biogas burned (consumption), which may require the supply of biogas to the gas storage unit to be stopped.

[0005] As a device for stopping the supply of biogas to a gas storage unit, for example, the following safety device for a methane fermentation treatment device has been proposed. This safety device includes a methane fermentation unit, a gas holder, and a water seal mechanism. When the pressure in either the methane fermentation unit or the gas holder becomes abnormally high, the water seal mechanism adjusts the pressure to a normal range. More specifically, in this safety device, if the pressure in the gas holder exceeds the maximum allowable pressure due to the supply of methane gas, the water seal is broken and the methane gas is released from the methane fermentation unit into the atmosphere (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 02-04400 Summary of the Invention [Problem to be solved by the invention]

[0007] On the other hand, biogas power generation systems are required to have improved power generation efficiency.

[0008] However, with the above safety device, the gas holder is normally sealed with water, but in certain cases the gas holder is not sealed with water, releasing methane gas into the atmosphere. In other words, the supply of methane gas to the gas holder is controlled on and off. As a result, the amount of methane gas stored in the gas holder cannot be appropriately adjusted, and sufficient power generation efficiency cannot be achieved.

[0009] The present invention is a biogas power generation system with excellent power generation efficiency. [Means for solving the problem]

[0010] The present invention [1] relates to a biogas generation tank that ferments organic waste to generate biogas, a biogas storage tank that receives the biogas from the biogas generation tank and stores the biogas, a biogas generator that receives the biogas from the biogas storage tank and generates electricity by burning the biogas, a power transmission system that transmits the electricity generated in the biogas generator, a temperature adjustment unit that adjusts the temperature of the biogas generation tank, a gas pressure detection unit that detects the gas pressure in the biogas storage tank, a failure detection unit that detects the presence and severity of a failure in the power transmission system, and a temperature adjustment unit, a gas pressure detection unit, and a failure detection unit. and a control unit connected to a monitoring unit, wherein when a failure of the power transmission system is detected by the failure detection unit, the control unit determines whether or not a reduction in the amount of biogas generated is necessary based on the detection by the gas pressure detection unit, and when it is determined that a reduction in the amount of biogas generated is necessary, the control unit predicts a required time for restoration of the power transmission system based on the degree of failure of the power transmission system detected by the failure detection unit, and the control unit adjusts the temperature of the biogas generation tank by controlling the temperature adjustment unit, thereby reducing the amount of biogas generated in accordance with the required time for restoration.

[0011] The present invention [2] includes the biogas power generation system described in [1] above, in which the control unit is capable of referring to date and time information, and the control unit predicts the time required to restore the power transmission system based on the degree of failure of the power transmission system detected by the failure detection unit and the date and time information. [Effects of the Invention]

[0012] In the biogas power generation system of the present invention, the control unit determines whether or not it is necessary to reduce the amount of biogas generated based on the detection by the gas pressure detection unit. If it is determined that it is necessary to reduce the amount of biogas generated, the control unit predicts the time required to restore the power transmission system based on the severity of the failure detected by the failure detection unit. Furthermore, the control unit adjusts the temperature of the biogas generation tank by controlling the temperature adjustment unit, and reduces the amount of biogas generated in accordance with the time required to restore the system.

[0013] In other words, in the case of a power transmission system failure, the biogas power generation system of the present invention does not completely stop the supply of biogas but adjusts the supply depending on the time required for the power transmission system to be restored, thereby achieving excellent power generation efficiency. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of a biogas power generation system of the present invention. [Figure 2] FIG. 2 is a flow diagram showing a control flow executed in the biogas power generation system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. Biogas power generation system (1) Overall structure Fig. 1 is a schematic diagram showing one embodiment of a biogas power generation system of the present invention. In Fig. 1, the biogas power generation system 1 is installed to consume biogas to generate electrical energy and transmit the electrical energy to electrically powered equipment 100. Examples of the electrical equipment 100 include electrically powered devices and electricity storage devices.

[0016] More specifically, the biogas power generation system 1 includes a biogas generation unit 2 that generates biogas, a biogas power generation unit 3 that burns (consumes) the biogas to generate electricity, and a control unit 4 that controls the biogas generation unit 2 and the biogas power generation unit 3.

[0017] (2) Biogas generation section The biogas generation unit 2 is provided to generate biogas and temporarily store the biogas. More specifically, the biogas generation unit 2 includes an organic waste storage tank 21, a biogas generation tank 23, and a biogas storage tank 23.

[0018] The organic waste storage tank 21 is a known tank for liquids and / or solids. The organic waste storage tank 21 is, for example, a known heat-resistant and pressure-resistant container. The organic waste storage tank 21 can store organic waste.

[0019] Organic waste, such as food waste, sewage, livestock waste, and food waste, produces methane gas through methane fermentation.

[0020] The biogas generation tank 22 is a known fermenter. The biogas generation tank 22 is made of, for example, a known heat-resistant and pressure-resistant container. Organic waste is supplied to the biogas generation tank 22, for example, via a waste transport pipe 24 described below.

[0021] The biogas generation tank 22 also contains microorganisms that contribute to the methane fermentation of organic waste, which allows the biogas generation tank 22 to generate biogas through methane fermentation of the organic waste, as will be described in detail later.

[0022] A temperature adjustment unit 41 (described later) is connected to the biogas generation tank 22. The internal temperature of the biogas generation tank 22 is adjusted by the temperature adjustment unit 41 (described later).

[0023] The biogas storage tank 23 is a known gas tank. The biogas storage tank 23 is made of, for example, a known heat-resistant and pressure-resistant container. For example, the biogas storage tank 23 is supplied with biogas via a biogas transport pipe 25, which will be described later.

[0024] As will be described in detail later, the biogas storage tank 23 can temporarily store the supplied biogas. A gas pressure detection unit 42 (described later) is connected to the biogas storage tank 23. The internal pressure of the biogas storage tank 23 is detected by the gas pressure detection unit 42 (described later).

[0025] The biogas generator 2 also includes a waste transport pipe 24, a biogas transport pipe 25, and a biogas supply pipe .

[0026] The waste transport pipe 24 is a known pipe. The waste transport pipe 24 connects the interior of the organic waste storage tank 21 with the interior of the biogas generation tank 22. Although not shown, the waste transport pipe 24 is also equipped with a pump and a valve. The organic waste is transported from the organic waste storage tank 21 to the biogas generation tank 22 by driving the pump in the waste transport pipe 24 and opening and closing the valve.

[0027] The biogas transport pipe 25 is a known pipe. The biogas transport pipe 25 connects the interior of the biogas generation tank 22 with the interior of the biogas storage tank 23. Although not shown, the biogas transport pipe 25 is also equipped with a pump and a valve. The biogas is transported from the biogas generation tank 22 to the biogas storage tank 23 by driving the pump of the biogas transport pipe 25 and opening and closing the valve.

[0028] Furthermore, the biogas transport pipe 25 may be equipped with a desulfurization device and / or a siloxane removal device as needed. In other words, the biogas may be subjected to desulfurization treatment and / or siloxane removal treatment as needed.

[0029] The biogas supply pipe 26 is a known pipe. The biogas supply pipe 26 connects the interior of the biogas storage tank 23 with the biogas power generation unit 3. Although not shown, the biogas supply pipe 26 is also equipped with a pump and a valve. The biogas is transported from the biogas storage tank 23 to the biogas power generation unit 3 by driving the pump of the biogas supply pipe 26 and opening and closing the valve.

[0030] (3) Biogas Power Generation Department The biogas power generation unit 3 is installed to consume biogas and extract electricity. The biogas power generation unit 3 burns (explodes) the biogas and converts the combustion energy into electrical energy to generate electricity. More specifically, the biogas power generation unit 3 includes a biogas generator 31 and a power transmission system 32.

[0031] The biogas generator 31 includes, for example, a known biogas engine 33 and a known generator 34 .

[0032] The biogas engine 33 generates power (kinetic energy) by burning biogas. The biogas engine 33 has, for example, a known reciprocating engine structure. Although not shown, the biogas engine 33 includes, for example, a fuel inlet, an air inlet, a piston, a combustion chamber, an igniter, and an exhaust port. The fuel inlet takes in biogas. The air inlet takes in air. The piston compresses the mixture of biogas and air. The igniter ignites the mixture of biogas and air. The combustion chamber combusts the mixture of biogas and air. The exhaust port exhausts the combustion gas of biogas. In this way, the biogas engine 33 generates power (kinetic energy).

[0033] The generator 34 converts the power (kinetic energy) generated in the biogas engine 33 into power (electrical energy). The generator 34 has a known configuration. For example, the generator 34 has a coil and a magnet. The coil and / or magnet rotates due to the power (kinetic energy) of the biogas engine 33. As a result, the generator 34 generates power through electromagnetic induction.

[0034] The power transmission system 32 has a known configuration. Although not shown, the power transmission system 32 includes, for example, a converter and a power conditioner. The power transmission system 32 is also electrically connected to the biogas generator 31. This allows the power transmission system 32 to transmit the power generated in the biogas generator 31 to any of the electrical devices 100.

[0035] (4) Control unit The control unit 4 is provided to control the biogas generation unit 2 and the biogas power generation unit 3 and improve power generation efficiency. More specifically, the control unit 4 includes a temperature adjustment unit 41, a gas pressure detection unit 42, and a failure detection unit 43, as well as a control unit 44 that controls these units.

[0036] The temperature adjustment unit 41 includes, for example, a known heat exchanger and a known temperature sensor. The heat exchanger is disposed outside the biogas generation tank 22. This allows the heat exchanger to adjust the internal temperature of the biogas generation tank 22. The temperature sensor is disposed, for example, inside the biogas generation tank 22. This allows the temperature sensor to detect the internal temperature of the biogas generation tank 22.

[0037] The temperature adjustment unit 41 (heat exchanger and temperature sensor) is also electrically connected (see dashed line) to a control unit 44, which will be described later. This allows the temperature adjustment unit 41 to input the internal temperature of the biogas generation tank 22 as an electrical signal to the control unit 44, which will be described later. The temperature adjustment unit 41 is also controlled by the control unit 44, which will be described later, and can adjust the internal temperature of the biogas generation tank 22 as desired.

[0038] The gas pressure detection unit 42 includes, for example, a known pressure sensor. The pressure sensor is disposed, for example, inside the biogas storage tank 23. This allows the pressure sensor to detect the internal pressure of the biogas storage tank 23.

[0039] The gas pressure detection unit 42 (pressure sensor) is also electrically connected (see dashed line) to a control unit 44, which will be described later. This allows the gas pressure detection unit 42 to input the internal pressure of the biogas storage tank 23 as an electrical signal to the control unit 44, which will be described later.

[0040] The fault detection unit 43 includes, for example, a known fault detection system. The fault detection system is placed, for example, at an appropriate location in the power transmission system 32, and monitors the operating status of the power transmission system 32 using a known method. For example, the fault detection unit 43 measures various parameters (for example, voltage values) at appropriate locations in the power transmission system 32 and analyzes them using a known method. In this way, the fault detection unit 43 can detect the presence or absence of a fault in the power transmission system 32 and the severity of the fault based on changes in the various parameters (for example, voltage values).

[0041] For example, if a component of the power transmission system 32 is damaged and the power transmission system 32 breaks down, an abnormality occurs in various parameters (for example, voltage values). The failure detection unit 43 can then detect the abnormality in various parameters (for example, voltage values) and determine whether or not the power transmission system 32 has broken down.

[0042] The degree of failure of the power transmission system 32 is determined, for example, according to damaged parts (hereinafter, "damaged parts"). More specifically, information for determining the degree of failure of the power transmission system 32 includes, for example, the type of damaged parts, the location of the damaged parts, the ease of obtaining the damaged parts, and the ease of replacing the damaged parts. The failure detection unit 43 can acquire the above information regarding the failure of the power transmission system 32 by an appropriate method, and determine the degree of failure.

[0043] The failure detection unit 43 is electrically connected (see dashed line) to a control unit 44, which will be described later. This allows the failure detection unit 43 to input, as an electrical signal, the presence or absence of a failure in the failure detection unit 43 and the severity of the failure to the control unit 44, which will be described later.

[0044] The control unit 44 is a control unit that performs electrical control in the biogas power generation system 1. The control unit 44 is equipped with a known memory and a calculation processing unit. The control unit 44 is electrically connected to the biogas engine 33 (see dashed line). This allows the control unit 44 to arbitrarily control the driving and stopping of the biogas engine 33.

[0045] The control unit 44 is also electrically connected to the temperature adjustment unit 41 (heat exchanger and temperature sensor) (see dashed line). This allows the control unit 44 to receive the internal temperature of the biogas generation tank 22 as an electrical signal. The control unit 44 also controls the temperature adjustment unit 41 to arbitrarily adjust the internal temperature of the biogas generation tank 22. The control unit 44 is also electrically connected to the gas pressure detection unit 42 (see dashed line). This allows the control unit 44 to receive the internal pressure of the biogas storage tank 23 as an electrical signal. The control unit 44 is also electrically connected to the power transmission system 32 (see dashed line). This allows the control unit 44 to receive, as an electrical signal, whether or not there is a malfunction in the power transmission system 32 and the severity of the malfunction.

[0046] The control unit 44 has a gas amount control program P. The gas amount control program P is a program for controlling the amount of biogas generated depending on whether or not there is a malfunction in the power transmission system 32 and the severity of the malfunction. The gas amount control program P is designed using a known method and stored in the memory of the control unit 44. The gas amount control program P is executed by the arithmetic processing unit when the biogas power generation system 1 is operated. This enables the control unit 44 to control the amount of biogas generated. A method for controlling the amount of biogas generated using the gas amount control program P will be described later.

[0047] Furthermore, the control unit 44 has a date and time database D as needed. The date and time database D is a database that includes date and time information (calendar information). The date and time information includes, for example, the current date and time, public holidays, weekdays, business days, and business hours.

[0048] The date and time database D is generated by a known method and stored in the control unit 44. This allows the control unit 44 to refer to date and time information. A method for controlling the amount of biogas generated using the date and time database D will be described later.

[0049] 2. Operation of biogas power generation system In the biogas power generation system 1, first, the internal temperature of the biogas generation tank 22 is controlled to a predetermined steady temperature by the temperature adjustment unit 41. The steady temperature inside the biogas generation tank 22 is, for example, 50°C or higher and 60°C or lower.

[0050] The organic waste then passes through the waste transport pipe 24 and is transported from the organic waste storage tank 21 to the biogas generation tank 22. As a result, the organic waste undergoes methane fermentation inside the biogas generation tank 22. As a result, biogas is generated. The main component of biogas is methane gas.

[0051] The biogas is then pretreated (desulfurization treatment and siloxane removal treatment) as necessary. The biogas then passes through a biogas transport pipe 25 and is transported from the biogas generation tank 22 to a biogas storage tank 23. The biogas is temporarily stored in the biogas storage tank 23. The biogas then passes through a biogas supply pipe 26 and is supplied to a biogas generator 31.

[0052] More specifically, biogas and air are mixed in the biogas generator 31. The mixture of biogas and air is then supplied to the biogas engine 33.

[0053] The biogas engine 33 burns biogas in a known manner to generate power (kinetic energy). More specifically, the biogas engine 33 first draws a mixture of air and biogas into a cylinder. Next, the biogas engine 33 compresses the mixture inside the cylinder with a piston. Next, the biogas engine 33 ignites the mixture, causing an explosion. Thereafter, the biogas engine 33 exhausts water vapor and combustion gases. By repeating this drive cycle, the biogas engine 33 generates power (kinetic energy).

[0054] The power (kinetic energy) generated by the biogas engine 33 is converted into power (electrical energy) in the generator 34. Specifically, the generator 34 uses the power (kinetic energy) generated by the biogas engine 33 to rotate magnets and / or coils, thereby generating power (electrical energy).

[0055] The electric power (electric energy) generated by the generator 34 is transmitted to the electric device 100 via the power transmission system 32.

[0056] 3.Adjusting the amount of biogas generated As described above, biogas is combusted (consumed) in the biogas power generation system 1. This generates electric power. The electric power is transmitted to the electric appliances 100 via the power transmission system 32.

[0057] Meanwhile, in the biogas power generation system 1, the power transmission system 32 may malfunction. When the power transmission system 32 malfunctions, the amount of power transmitted to the electrical device 100 decreases. In such a case, the amount of biogas burned (consumed) decreases in accordance with the decrease in power.

[0058] When the amount of biogas burned (amount consumed) decreases, the amount of biogas stored in the biogas storage tank 23 increases. In such a case, the internal pressure of the biogas storage tank 23 increases. If the internal pressure of the biogas storage tank 23 exceeds a predetermined value in this way, the biogas storage tank 23 will be damaged.

[0059] Therefore, in the biogas power generation system 1 described above, the amount of biogas generated is adjusted in response to a failure in the power transmission system 32 by the following method.

[0060] The following describes in detail the method for controlling the amount of biogas generated by the gas amount control program P. FIG. 2 is a flow chart showing the control flow executed in the biogas power generation system shown in FIG.

[0061] The gas amount control program P is executed (start S1) when, for example, the biogas power generation system 1 starts operating (actuating).

[0062] When the gas amount control program P is executed, first, the fault detection unit 43 detects whether or not there is a fault in the power transmission system 32 and the severity of the fault (hereinafter referred to as fault information). The fault information of the power transmission system 32 is input as an electrical signal to the gas amount control program P. Then, the gas amount control program P determines whether or not there is a fault in the power transmission system 32 (S2).

[0063] If the gas amount control program P determines that there is no failure in the power transmission system 32 (S2; NO), the control unit 44 operates the biogas power generation system 1 in the steady mode (S3).

[0064] The steady mode is an operation mode of the biogas power generation system 1 when the failure detection unit 43 does not detect a failure in the power transmission system 32.

[0065] More specifically, in the steady mode, the control unit 44 controls the temperature adjustment section 41 to adjust the temperature inside the biogas generation tank 22 to a predetermined steady temperature (for example, 50°C or higher and 60°C or lower). This adjusts the amount of biogas generated to a predetermined steady amount. The biogas is stored in the biogas storage tank 23. The biogas is then consumed by the biogas engine 33 to generate electricity.

[0066] On the other hand, if the gas amount control program P determines that there is a malfunction in the power transmission system 32 (S2; YES), the control unit 44 operates the biogas power generation system 1 in an abnormal mode (S4).

[0067] The abnormality mode is an operating mode of the biogas power generation system 1 when a failure in the power transmission system 32 is detected by the failure detection unit 43. In the abnormality mode, the control unit 44 first determines whether or not a reduction in the amount of biogas generated is necessary based on the detection by the gas pressure detection unit 42.

[0068] More specifically, in the abnormality mode, the gas pressure detection unit 42 detects the magnitude of the internal pressure (hereinafter referred to as pressure information) of the biogas storage tank 23. The pressure information of the biogas storage tank 23 is input as an electrical signal to the control unit 44. Then, the control unit 44 determines whether the magnitude of the internal pressure of the biogas storage tank 23 is equal to or greater than a predetermined value (S5).

[0069] If the control unit 44 determines that the internal pressure of the biogas storage tank 23 is less than the predetermined value (S5; NO), it determines that there is little possibility of damage to the biogas storage tank 23. In this case, the control unit 44 operates the biogas power generation system 1 in the maintenance mode (S6).

[0070] The maintenance mode is an operation mode of the biogas power generation system 1 when a failure in the power transmission system 32 is detected by the failure detection unit 43 and there is no need to reduce the amount of biogas generated. In the maintenance mode, the control unit 44 operates the biogas power generation system 1 under the same conditions as in the above-mentioned steady mode, for example.

[0071] More specifically, in the maintenance mode, the control unit 44 controls the temperature adjustment section 41 to adjust the temperature inside the biogas generation tank 22 to a predetermined steady temperature (for example, 50°C or higher and 60°C or lower). This adjusts the amount of biogas generated to a predetermined steady amount. The biogas is stored in the biogas storage tank 23. The biogas is then consumed in the biogas engine 33 to generate electricity.

[0072] On the other hand, if the control unit 44 determines that the internal pressure of the biogas storage tank 23 is equal to or greater than the predetermined value (S5; YES), the control unit 44 operates the biogas power generation system 1 in a reduced pressure mode (S7).

[0073] The pressure reduction mode is an operating mode of the biogas power generation system 1 when the failure detection unit 43 detects a failure in the power transmission system 32 and determines that the amount of biogas generated needs to be reduced. In the pressure reduction mode, the biogas power generation system 1 is operated so as to reduce the internal pressure of the biogas storage tank 23.

[0074] More specifically, in the pressure reduction mode, the control unit 44 predicts the time required to restore the power transmission system 32, depending on the degree of the failure of the power transmission system 32 detected by the failure detection unit 43. Then, the control unit 44 controls the temperature adjustment unit 41 to adjust the temperature of the biogas generation tank 22, and reduces the amount of biogas generated depending on the time required to restore the power transmission system 32.

[0075] More specifically, in the pressure reduction mode, the control unit 44 determines the degree of failure of the power transmission system 32 based on the failure information of the power transmission system 32 (S8). As described above, information for determining the degree of failure of the power transmission system 32 includes, for example, the type of damaged part, the location of the damaged part, the ease of obtaining the damaged part, and the ease of replacing the damaged part.

[0076] If the control unit 44 determines that the degree of failure of the power transmission system 32 is equal to or greater than a predetermined level (S8; YES), the control unit 44 predicts that it will take a relatively long time to restore the power transmission system 32. In such a case, the control unit 44 operates the biogas power generation system 1 in a long-term depressurization mode (S9).

[0077] In the long-term pressure reduction mode, the biogas power generation system 1 is operated so as to reduce the internal pressure of the biogas storage tank 23 for a relatively long period of time.

[0078] More specifically, in the long-term decompression mode, the control unit 44 controls the temperature adjustment section 41 to lower the temperature inside the biogas generation tank 22 (S10). Then, the control unit 44 determines whether the temperature inside the biogas generation tank 22 has lowered to a predetermined first low temperature (long-term decompression temperature; T1) (S11).

[0079] The first low temperature is lower than the steady temperature and lower than the second low temperature described below. The first low temperature reduces the amount of biogas generated relatively significantly. More specifically, the first low temperature is, for example, not lower than 30°C and not higher than 40°C. The difference between the first low temperature and the steady temperature is, for example, not lower than 10°C and not higher than 30°C.

[0080] The amount of biogas generated at the first low temperature is, for example, 50% or less, preferably 30% or less, of the amount of biogas generated at the steady temperature. Also, the amount of biogas generated at the first low temperature is, for example, 1% or more of the amount of biogas generated at the steady temperature.

[0081] If the control unit 44 determines that the temperature inside the biogas generation tank 22 has not dropped to the first low temperature (long-term reduced pressure temperature; T1) (S11; NO), the control unit 44 continues to control the temperature adjustment unit 41 to lower the temperature inside the biogas generation tank 22 to the first low temperature (long-term reduced pressure temperature; T1).

[0082] On the other hand, when the control unit 44 causes the temperature inside the biogas generation tank 22 to drop to the first low temperature (long-term decompression temperature; T1) (S11; YES), the amount of biogas generated decreases relatively greatly compared to the steady mode. As a result, the internal pressure of the biogas storage tank 23 is reduced for a relatively long period of time compared to the steady mode.

[0083] On the other hand, if the control unit 44 determines that the degree of the failure of the power transmission system 32 is not equal to or greater than the predetermined level (S8; NO), the control unit 44 then refers to the date and time information (date and time database D) (S12). Then, the control unit 44 predicts the time required to restore the power transmission system 32 according to the degree of the failure of the power transmission system 32 and the date and time information.

[0084] More specifically, the control unit 44 checks, for example, the type of damaged part, the location of the damaged part, the availability of the damaged part, and the ability to replace the damaged part. The control unit 44 also checks the current date and time information. As described above, the date and time information may include, for example, the current date and time, public holidays, weekdays, business days, and business hours.

[0085] Then, the control unit 44 determines whether replacement and / or repair of the damaged parts can be completed within a predetermined period of time based on the degree of the failure of the power transmission system 32 and the date and time information. In other words, the control unit 44 determines whether the failure of the power transmission system 32 can be addressed in the near future (S13).

[0086] If the control unit 44 determines that the power transmission system 32 will not be able to be restored in the near future (S13; NO), the control unit 44 predicts that the time required to restore the power transmission system 32 will be relatively long. In such a case, the control unit 44 operates the biogas power generation system 1 in the long-term depressurization mode described above (S9).

[0087] On the other hand, if the control unit 44 determines that the problem can be solved in the near future (S13; YES), the control unit 44 predicts that the time required to restore the power transmission system 32 will be relatively short. In such a case, the control unit 44 operates the biogas power generation system 1 in the short-term depressurization mode (S14).

[0088] In the short-term pressure reduction mode, the biogas power generation system 1 is operated to reduce the internal pressure of the biogas storage tank 23 for a relatively short period of time.

[0089] More specifically, in the short-term decompression mode, the control unit 44 controls the temperature adjustment section 41 to lower the temperature inside the biogas generation tank 22 (S15). Then, the control unit 44 determines whether the temperature inside the biogas generation tank 22 has lowered to a predetermined second low temperature (short-term decompression temperature; T2) (S16).

[0090] The second low temperature is lower than the steady temperature and higher than the first low temperature. The second low temperature reduces the amount of biogas generated by a relatively small amount. More specifically, the second low temperature is, for example, 40°C or higher and lower than 50°C. The difference between the second low temperature and the steady temperature is, for example, 1°C or higher and 20°C or lower. The difference between the second low temperature and the first temperature is, for example, 1°C or higher and 20°C or lower.

[0091] The amount of biogas generated at the second low temperature is, for example, 90% or less, preferably 70% or less, of the amount of biogas generated at the steady temperature. Also, the amount of biogas generated at the second low temperature is, for example, 50% or more of the amount of biogas generated at the steady temperature.

[0092] The amount of biogas generated at the second low temperature is, for example, 110% or more, preferably 120% or more, of the amount of biogas generated at the first low temperature.The amount of biogas generated at the second low temperature is, for example, 300% or less of the amount of biogas generated at the first low temperature.

[0093] If the control unit 44 determines that the temperature inside the biogas generation tank 22 has not dropped to the first low temperature (short-term decompression temperature; T2) (S16; NO), the control unit 44 continues to control the temperature adjustment unit 41 to drop the temperature inside the biogas generation tank 22 to the second low temperature value (short-term decompression temperature; T2).

[0094] On the other hand, when the control unit 44 causes the temperature inside the biogas generation tank 22 to drop to the second low temperature (short-term depressurization temperature; T2) (S16; YES), the amount of biogas generated decreases by a relatively small amount compared to the steady mode. As a result, the internal pressure of the biogas storage tank 23 is reduced for a relatively short period of time compared to the steady mode.

[0095] Then, the control unit 44 (gas amount control program P) continues (returns) the above processing while the biogas power generation system 1 is operating. As a result, the control unit 44 controls the amount of biogas generated in accordance with the time required to restore the power transmission system 32.

[0096] 4. Effects As described above, in the biogas power generation system 1, the amount of biogas burned (consumption) may decrease due to a failure in the power transmission system 32. In such a case, it is required to reduce the supply of biogas to the biogas storage tank 23.

[0097] In such a case, if the supply of biogas to the biogas storage tank 23 is simply stopped completely when the power transmission system 32 fails, the amount of biogas stored in the biogas storage tank 23 cannot be adjusted appropriately, and sufficient power generation efficiency cannot be achieved.

[0098] In contrast, in the biogas power generation system 1 described above, the control unit 44 determines whether or not it is necessary to reduce the amount of biogas generated, based on the detection by the gas pressure detection unit 42. If it is determined that it is necessary to reduce the amount of biogas generated, the control unit 44 predicts the time required to restore the power transmission system 32, based on the degree of failure detected by the failure detection unit 43. Furthermore, the control unit adjusts the temperature of the biogas generation tank 22 by controlling the temperature adjustment unit 41, and reduces the amount of biogas generated in accordance with the time required to restore the biogas.

[0099] That is, in the above biogas power generation system 1, when a failure occurs in the power transmission system 32, the supply of biogas is not completely stopped, but is adjusted according to the time required to restore the power transmission system 32. Therefore, the above biogas power generation system 1 has excellent power generation efficiency.

[0100] 5. Variations In the above embodiment, the control unit 44 refers to the date and time information, but the control unit 44 does not have to refer to the date and time information.

[0101] More specifically, if the degree of the failure of the power transmission system 32 is not at a predetermined level or above, it can be automatically determined that the problem can be dealt with in the near future without referring to the date and time information.

[0102] In such a case, for example, if the control unit 44 determines that the degree of failure of the power transmission system 32 is not equal to or greater than a predetermined level (S8; NO), the control unit 44 operates the biogas power generation system 1 in short-term depressurization mode (S14) without referring to the date and time information (date and time database D). The other control flows are the same as those described above.

[0103] In this type of biogas power generation system 1, when the power transmission system 32 fails, the supply of biogas is not completely stopped but is adjusted depending on the time required to restore the power transmission system 32. Therefore, this type of biogas power generation system 1 also has excellent power generation efficiency. [Explanation of symbols]

[0104] 1. Biogas power generation system 22 Biogas generation tank 23 Biogas storage tank 31 Biogas Generator 32 Power Transmission System 41 Temperature adjustment section 42 Gas pressure detector 43 Failure detection unit 44 Control Unit

Claims

1. a biogas generation tank for fermenting organic waste to generate biogas; a biogas storage tank that receives the biogas from the biogas generation tank and stores the biogas; a biogas generator that receives the biogas from the biogas storage tank and generates electricity by burning the biogas; a power transmission system that transmits the electricity generated in the biogas generator; a temperature adjustment unit that adjusts the temperature of the biogas generation tank; a gas pressure detection unit that detects the gas pressure in the biogas storage tank; a failure detection unit that detects the presence or absence and severity of a failure in the power transmission system; a control unit connected to the temperature adjustment unit, the gas pressure detection unit, and the failure detection unit; Equipped with When a failure in the power transmission system is detected by the failure detection unit, the control unit determines whether or not the amount of biogas generated needs to be reduced based on the detection by the gas pressure detection unit, When it is determined that the amount of biogas generated needs to be reduced, the control unit predicts a required time for restoration of the power transmission system according to the degree of the failure of the power transmission system detected by the failure detection unit; The control unit adjusts the temperature of the biogas generation tank by controlling the temperature adjustment unit, and reduces the amount of biogas generated in accordance with the required recovery time.

2. The control unit is capable of referring to date and time information, The biogas power generation system according to claim 1, wherein the control unit predicts the time required to restore the power transmission system based on the degree of failure of the power transmission system detected by the failure detection unit and the date and time information.

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