Heat source machine system, heat source machine system operation method

Abstract

To easily and efficiently utilize the mixed gas mainly composed of hydrocarbon and hydrogen.SOLUTION: A heat-source machine system 10A includes: a fuel-cell cell stack 20 in which the mixed gas mainly composed of hydrocarbon and hydrogen supplied from a gas conduit G is supplied to a fuel electrode 20A without being reformed and the hydrogen in the mixed gas is used in the power generation reaction to generate power; a heat source machine 30 having a burner 32 which burns the fuel electrode off-gas discharged from the fuel electrode 20A of the fuel-cell cell stack 20 and a heat exchanger 34 which exchanges heat between the combustion heat by the burner 32 and the fluid to be heated; and a controller 40 which controls a fuel supply blower 24 so that the mixed gas is supplied to the fuel-cell cell stack 20 only when the heat source machine 30 is in operation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat source machine system and a method for operating the heat source machine system. [Background technology]

[0002] Toward the realization of a low-carbon society, the use of mixed gases, which are hydrocarbon gases whose main component is methane, such as conventional city gas, mixed with hydrogen, is being considered. However, when such mixed gases are supplied through gas pipelines, how users should deal with the situation becomes an issue.

[0003] In Patent Documents 1 and 2, when hydrogen fuel equipment and existing gas combustion equipment coexist, in order to use both equipment without any problems, the hydrogen and hydrocarbon gas in the mixed gas are separated, and the separated, unused gas that cannot be used by the equipment is returned to the pipeline and supplied to other consumers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4530193 [Patent Document 2] Patent No. 4721525 Summary of the Invention [Problem to be solved by the invention]

[0005] When the separated gas is returned to the gas pipeline as in Patent Documents 1 and 2, variations in the hydrogen and hydrocarbon concentrations of the returned gas occur, and the gas pipeline system becomes large. On the other hand, it is also possible to burn the mixed gas in an existing gas combustion appliance, but this does not allow for efficient use of hydrogen. When users of hydrogen fuel equipment and existing gas combustion appliances coexist on the consumer side, a method for easily and efficiently using the mixed gas is required.

[0006] The present invention has been made in consideration of the above circumstances, and has as its object to easily and efficiently utilize a mixed gas containing hydrocarbons and hydrogen as its main components. [Means for solving the problem]

[0007] The heat source equipment system according to claim 1 comprises a heat source equipment having a fuel cell to which a mixed gas containing hydrocarbons and hydrogen as main components is supplied from a gas conduit and which generates electricity by using the hydrogen in the mixed gas in a power generation reaction, a burner to combust anode off-gas discharged from the anode of the fuel cell, and a heat exchanger to exchange heat between the combustion heat from the burner and a fluid to be heated, and a heat source equipment system configured so that the mixed gas is supplied to the anode only when there is a request to operate the heat source equipment. And when a stop command is given to the heat source machine, the power generation operation is stopped. and a control unit that controls the operation of the heat source unit and the fuel cell.

[0008] In the heat source equipment system according to claim 1, a mixed gas containing hydrocarbons and hydrogen from a gas conduit is supplied to an anode of a fuel cell, and the hydrogen in the mixed gas is used to generate electricity in the fuel cell. Anode off-gas that is not used to generate electricity and is discharged from the anode is used for combustion in a burner of the heat source equipment, and heat exchange occurs in a heat exchanger between the combustion heat from the burner and a fluid to be heated, thereby heating the fluid to be heated.

[0009] According to the heat source equipment system of claim 1, the hydrogen in the mixed gas is used in the fuel cell, and unused hydrocarbons, hydrogen, etc. are used in the heat source equipment. Therefore, compared to when hydrogen and hydrocarbons are combusted and used only in the heat source equipment, more energy is obtained for the energy supplied, and the mixed gas can be used efficiently.

[0010] Furthermore, the control unit supplies the mixed gas to the anode only when there is a request to operate the heat source unit. Here, "when there is a request to operate the heat source unit" means that there is a request to operate the heat source unit and the heat source unit is operating in response to the request. Therefore, a situation will not occur where only the fuel cell is operating and the heat source unit is not operating, and the anode off-gas, which is discharged from the fuel cell and contains hydrocarbons and unused hydrogen, can be appropriately processed in the heat source unit. Furthermore, there is no need to install separate equipment for processing the anode off-gas, and no separation device is required, resulting in a simple configuration.

[0011] In the heat source machine system according to claim 2, the control unit controls the fuel cell to start power generation operation when it determines that the continuous operation time of the heat source machine is equal to or longer than a predetermined power generation possible time.

[0012] According to the heat source machine system of claim 2, when it is determined that the continuous operation time of the heat source machine is equal to or longer than a predetermined power generation time, the fuel cell power generation operation is started, thereby suppressing inefficient short-term power generation operation of the fuel cell.

[0013] The heat source system according to claim 3 has an electric heater arranged upstream of the heat exchanger in the flow path of the fluid to be heated and heating the fluid to be heated, and the electricity generated by the fuel cell is supplied to the user's power consumption, with the surplus being supplied to the electric heater.

[0014] According to the heat source system of claim 3, the surplus power generated by the fuel cell is supplied to the electric heater, which heats the fluid to be heated upstream of the heat exchanger, thereby making it possible to efficiently utilize the surplus power.

[0015] A heat source equipment system operating method according to claim 4 is a heat source equipment system operating method that utilizes a mixed gas mainly composed of hydrocarbons and hydrogen supplied from a gas conduit, and includes a heat source equipment that, downstream of a fuel cell that generates electricity using hydrogen in the mixed gas in a power generation reaction, burns anode off-gas discharged from the anode of the fuel cell with a burner to heat a fluid to be heated with the combustion heat, and supplies the mixed gas to the fuel cell only when there is a request to operate the heat source equipment. When an instruction to stop the heat source machine is given, the power generation operation of the fuel cell is stopped. do.

[0016] In the heat source equipment system operating method according to claim 4, power is generated using hydrogen in a mixed gas mainly composed of hydrocarbons and hydrogen supplied from a gas conduit, anode off-gas discharged from the anode of the fuel cell is combusted in a burner of the heat source equipment, and the combustion heat heats a fluid to be heated. Therefore, the mixed gas can be used more efficiently than when hydrogen and hydrocarbons are combusted and used only in the heat source equipment.

[0017] Furthermore, because the mixed gas is supplied to the fuel cell only when there is a request to operate the heat source unit, a situation in which only the fuel cell is operating and the heat source unit is not operating occurs, and the anode off-gas, which is discharged from the fuel cell and contains hydrocarbons and unused hydrogen, can be appropriately treated in the heat source unit. Furthermore, there is no need to provide a separate device for treating the anode off-gas, and no separation device is required, resulting in a simple configuration. [Effects of the Invention]

[0018] According to the heat source equipment system and the heat source equipment system operating method of the present invention, a mixed gas containing hydrocarbons and hydrogen as main components can be easily and efficiently utilized. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a configuration diagram of a heat source machine system according to a first embodiment. [Figure 2] FIG. 2 is a configuration diagram of control-related components of the heat source machine system according to the first embodiment. [Figure 3] 4 is a flowchart of a power generation control process. [Figure 4] FIG. 10 is a configuration diagram of a heat source machine system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] First Embodiment A first embodiment of the present invention will be described with reference to the drawings.

[0021] The heat source machine system 10A is a system installed in a user's home, an apartment building, etc. for heating a fluid to be heated, such as water, and is a heat source device for hot water supply equipment, hot water floor heating equipment, etc. Fig. 1 shows an outline of the main configuration of the heat source machine system 10A according to an embodiment of the present invention. The heat source machine system 10A according to an embodiment of the present invention includes, as its main components, a power generation unit 12 and a heat source machine 30.

[0022] The heat source equipment system 10A is supplied with a mixed gas from a gas conduit G that supplies gas to a predetermined area. The mixed gas is a gas whose main components are hydrogen and hydrocarbons, and one example is a gas obtained by mixing city gas with hydrogen. Also, as one example, the hydrogen concentration in the mixed gas can be set to approximately 0.1% to 10%, and the methane concentration can be set to approximately 90% to 99.9%. A fuel supply pipe P1 is provided branching from the gas conduit G, and the mixed gas is supplied to the heat source equipment system 10A via the fuel supply pipe P1.

[0023] The power generation unit 12 is a device that generates power using hydrogen from a mixed gas, and includes a desulfurizer 14, a fuel cell stack 20, an air supply blower 22, a fuel supply blower 24, and a power conditioner 26.

[0024] The fuel cell stack 20 is a cell stack having a plurality of stacked fuel cell units. The fuel cell stack 20 is an example of a fuel cell in the present invention, and each fuel cell unit has an electrolyte layer (not shown), and a fuel electrode 20A and an air electrode 20B stacked on the front and back surfaces of the electrolyte layer, respectively. Note that various fuel cells can be used as the fuel cell stack 20, such as a solid oxide fuel cell (SOFC), a molten carbonate fuel cell (MCFC), and a polymer electrolyte fuel cell (PEFC). In this embodiment, a PEFC will be described as an example.

[0025] A fuel supply pipe P1 is connected to the inlet side of the anode 20A, and an air supply pipe P2 is connected to the inlet side of the cathode 20B. A fuel supply blower 24 and a desulfurizer 14 are provided in the fuel supply pipe P1, in that order from upstream. The fuel supply blower 24 sends the mixed gas toward the anode 20A at a specified flow rate. The desulfurizer 14 removes sulfur components that act as odorants in the mixed gas. The mixed gas from which the sulfur components have been removed contains hydrogen and methane, and is supplied to the anode 20A of the fuel cell stack 20 without being reformed. An air supply blower 22 is provided in the air supply pipe P2, and air is supplied to the cathode 20B by the air supply blower 22.

[0026] An anode off-gas pipe P3 is connected to the outlet side of the anode 20A, and an anode off-gas pipe P4 is connected to the outlet side of the cathode 20B. The downstream end of the anode off-gas pipe P3 is connected to a burner 32 (described later) of the heat source unit 30. The anode off-gas discharged from the cathode 20B is released into the atmosphere from the anode off-gas pipe P4. The anode off-gas discharged from the anode 20A is supplied to the burner 32 via the anode off-gas pipe P3.

[0027] A power conditioner 26 is electrically connected to the fuel cell stack 20. The power conditioner 26 controls the power output from the fuel cell stack 20 and supplies the power to users.

[0028] The heat source device 30 is a device that heats a fluid to be heated using, as fuel, anode off-gas discharged from the anode 20A of the fuel cell stack 20 of the power generation unit 12, and has a burner 32 and a heat exchanger 34. Clean water is supplied to the heat exchanger 34 from a water supply pipe P5.

[0029] An anode off-gas pipe P3 is connected to the burner 32, and anode off-gas discharged from the anode 20A of the fuel cell stack 20 is supplied to the burner 32. The burner 32 is disposed adjacent to the heat exchanger 34. The burner 32 combusts combustible components in the anode off-gas, and heats the clean water supplied to the heat exchanger 34 with the combustion heat.

[0030] The clean water heated by the heat exchanger 34 is sent out through a pipe P7 and supplied for hot water supply and floor heating. The combustion exhaust gas from the burner 32 is discharged through an exhaust gas pipe P6.

[0031] 2 shows a schematic block diagram of a control system of the heat source equipment system 10A. The heat source equipment system 10A is provided with a controller 40, which controls the power generation unit 12 and the heat source equipment 30.

[0032] As shown in FIG. 2, the controller 40 includes a CPU (Central Processing Unit) 41, a ROM (Read Only Memory) 42, a RAM (Random Access Memory) 43, an input / output interface (I / F) 44, and a storage unit 45.

[0033] The CPU 41, ROM 42, RAM 43, and I / F 44 are connected to each other via a bus 46. The I / F 44 is connected to each of the functional units including the storage unit 45. These functional units are capable of communicating with the CPU 41 via the I / F 44.

[0034] For example, a hard disk drive (HDD), a solid state drive (SSD), a flash memory, or the like is used as the storage unit 45. Control programs for controlling each part of the heat source machine system 10A and various types of data are stored in the storage unit 45. Note that these control programs and various types of data may be stored in the ROM 42.

[0035] In this embodiment, a power generation control processing program and the like are stored as part of the control program. Furthermore, power generation condition information I and the like are stored as data used in this processing.

[0036] The power generation condition information I is a condition for the power generation unit 12 to perform power generation operation. In this embodiment, the condition for power generation operation is the operation of the heat source device 30, and also when an input to start floor heating is received from the operation panel 50, an input to start filling the bathtub is received, or the hot water supply time is equal to or longer than a predetermined time T. The predetermined time T can be set to, for example, 10 to 20 seconds, which is shorter than the time required for floor heating or filling the bathtub, or a time that is shorter than the time required for floor heating or filling the bathtub but that allows the user to use hot water for a certain amount of time. The time required for floor heating, the time required to fill the bathtub, and the predetermined time T or longer are examples of the power generation possible time in the present invention.

[0037] The controller 40 is connected to the air supply blower 22, the fuel supply blower 24, the power conditioner 26, the burner 32, an operation panel 50, etc. The operation panel 50 has a display, lamps, switches, etc., and allows the user to input various instructions, and also displays the status of the heat source machine system 10A, etc.

[0038] Next, the operation of the heat source machine system 10A will be described.

[0039] When the user turns on the power of the heat source machine system 10A from the operation panel 50, the controller 40 executes the power generation control process shown in FIG.

[0040] In step S10, it is determined whether or not an instruction to drive the heat source machine 30 has been received, and if the determination is affirmative, in step S12, the operation of the heat source machine 30 is started. If the determination is negative, the system waits until an instruction to drive the heat source machine is received. An instruction to drive the heat source machine 30 is given by a user input from the operation panel 50 (to start floor heating, to fill the bathtub with water, etc.) or by the release of clean water exceeding the minimum ignition flow rate.

[0041] When the heat source device 30 starts to operate, the fuel supply blower 24 is driven, and the mixed gas is supplied from the gas conduit G without being reformed, through the desulfurizer 14 and the anode 20A of the fuel cell stack 20, to the burner 32 of the heat source device 30. The mixed gas (anode off-gas) is then combusted in the burner 32, and water, which is the fluid to be heated and supplied to the heat exchanger 34, is heated by the heat of combustion. Note that, although the present embodiment will be described taking water as an example of the fluid to be heated, other fluids such as antifreeze (in the case of floor heating) may also be used.

[0042] In step S14, it is determined whether the power generation conditions are met. Whether the power generation conditions are met is determined by whether the power generation condition information I stored in the memory unit 45 is met. In this embodiment, the determination is made positive when an input to start floor heating is received from the operation panel 50, an input to start filling the bathtub is received, or the hot water supply time after the tap water has been supplied is equal to or longer than a predetermined time T.

[0043] If it is determined in step S14 that the power generation conditions are met, then in step S16 a command to start power generation operation is output in the power generation unit 12. When power generation starts, the air supply blower 22 is driven to supply air to the air electrode 20B, and the power conditioner 26 starts power generation output from the fuel cell stack 20. As a result, the hydrogen in the mixed gas supplied to the fuel cell stack 20 is used and consumed in the power generation reaction, and the anode off-gas after hydrogen consumption is supplied to the burner 32. In the burner 32, the anode off-gas after hydrogen consumption in the fuel cell stack 20 is combusted.

[0044] Next, in step S18, the system waits until an instruction to stop the heat source unit 30 is received, and if an instruction to stop the heat source unit 30 is received, an instruction to stop the heat source unit 30 is output in step S20, and the power generation operation of the power generation unit 12 is stopped in step S22.

[0045] In step S24, it is determined whether or not a stop command for the heat source machine system 10A has been issued, and if the determination is affirmative, this process is terminated. If a stop command for the heat source machine system 10A has not been issued, the process returns to step S10, and the above process is repeated.

[0046] In the heat source equipment system 10A of this embodiment, hydrogen in the mixed gas is used to generate electricity in the fuel cell stack 20, and combustible components such as methane that are not used in the fuel cell stack 20 are used in the heat source equipment 30. Therefore, compared to when a mixed gas containing hydrogen and methane is combusted and used only by the burner 32 of the heat source equipment 30, the mixed gas can be used more efficiently.

[0047] Furthermore, since the mixed gas supplied to the fuel cell stack 20 contains hydrogen, a reformer is not required, resulting in a simple configuration. In this embodiment, the mixed gas is supplied to the fuel electrode 20A of the fuel cell stack 20 without being reformed, but reformed gas (containing unreformed combustible components such as hydrogen and methane) reformed using a reformer may also be supplied to the fuel electrode 20A.

[0048] Furthermore, in this embodiment, the mixed gas is supplied to the anode 20A of the fuel cell stack 20 only when there is a request to operate the heat source device 30, so the anode off-gas containing combustible components that is discharged from the fuel cell stack 20 can be appropriately treated in the heat source device 30 without being discharged to the outside. Note that the supply of the mixed gas to the anode 20A here also includes cases where the power generation operation of the power generation unit 12 is not being performed.

[0049] Furthermore, in this embodiment, when it is determined that the continuous operation time of the heat source device 30 is equal to or greater than the floor heating time, the bathtub filling time, and the predetermined time T, the power generating operation of the fuel cell stack 20 is started, thereby making it possible to suppress inefficient power generating operation of the fuel cell stack 20. Note that it is not necessary to start the power generating operation of the fuel cell stack 20 when it is determined that the continuous operation time of the heat source device 30 is equal to or greater than the floor heating time, the bathtub filling time, and the predetermined time T, and the power generating operation of the fuel cell stack 20 may be started simultaneously with the operation of the heat source device 30.

[0050] Second Embodiment Next, a second embodiment of the present invention will be described. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0051] 4, the heat source machine system 10B of this embodiment differs from the first embodiment mainly in that it has a heater 52. The heater 52 is an electric heater, and is connected to a water supply pipe P5. The heater 52 heats the clean water from the water supply pipe P5 and sends it to the heat exchanger 34.

[0052] The power conditioner 26 supplies power to the user in accordance with the load power, and if surplus power occurs, supplies the surplus power to the heater 52.

[0053] In this embodiment, surplus power generated by the fuel cell stack 20 is supplied to the heater 52, and the clean water, which is the fluid to be heated, is heated upstream of the heat exchanger 34. Therefore, surplus power can be used efficiently.

[0054] The above describes an embodiment of the present invention, but the present invention is not limited to the above, and it goes without saying that the present invention can be implemented in various modified forms within the scope of the gist of the present invention. [Explanation of symbols]

[0055] 10A, 10B Heat source system 20 Fuel cell stack (fuel cell) 20A fuel electrode 24 Fuel supply blower (fuel supply section) 30 Heat source machine 32 Burner 34 Heat exchanger 40 Controller (control unit) 52 Heater (electric heater) G Gas pipeline P5 Water supply pipe (flow path)

Claims

1. a fuel cell in which a mixed gas containing hydrocarbons and hydrogen as main components supplied from a gas conduit is supplied to an anode by a fuel supply unit, and the hydrogen in the mixed gas is used in a power generation reaction to generate power; a heat source machine having a burner that combusts anode off-gas discharged from the anode of the fuel cell, and a heat exchanger that exchanges heat between combustion heat from the burner and a fluid to be heated; a control unit that controls the fuel supply unit so that the mixed gas is supplied to the anode only when there is an operation request for the heat source unit, and so that the power generation operation is stopped when a stop command is given to the heat source unit; A heat source system equipped with the above.

2. the control unit controls the fuel cell so that a power generation operation of the fuel cell is started when it is determined that the operation duration of the heat source machine is equal to or longer than a predetermined power generation possible time. The heat source system according to claim 1 .

3. an electric heater disposed upstream of the heat exchanger in the flow path of the fluid to be heated, the electric heater heating the fluid to be heated; The electric power generated by the fuel cell is supplied to the user's power consumption, and the surplus is supplied to the electric heater. The heat source machine system according to claim 1 or 2.

4. A method for operating a heat source system that utilizes a mixed gas containing hydrocarbons and hydrogen as main components supplied from a gas conduit, a heat source device that is disposed downstream of a fuel cell that generates electricity by using hydrogen in the mixed gas in a power generation reaction, and that burns anode off-gas discharged from a cathode of the fuel cell using a burner to heat a fluid to be heated with the combustion heat; The mixed gas is supplied to the fuel cell only when the heat source device is operating, and when an instruction to stop the heat source device is received, the power generation operation of the fuel cell is stopped. Heat source system operation method.

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