JP2023149029A - Heat source machine system and method for operating heat source machine system - Google Patents

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 mixture gas containing the mixed gas mainly composed of hydrocarbon and hydrogen is supplied from a gas conduit G to a fuel electrode 20A without being reformed; and 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 performs the heat exchange between the combustion heat by the burner 32 and the fluid to be heated.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat source device system and a heat source device system operating method.

In order to realize a low-carbon society, consideration is being given to using a mixed gas in which hydrogen is mixed with a hydrocarbon gas whose main component is methane, such as conventional city gas. When such a mixed gas is supplied from a gas conduit, the user's response becomes a problem.

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

Patent No. 4530193 Patent No. 4721525

When the separated gas is returned to the gas conduit as in Patent Documents 1 and 2, variations occur in the concentration of hydrogen and hydrocarbons in the returned gas, and the gas conduit system becomes large-scale. On the other hand, it is conceivable to burn the mixed gas with existing gas combustion equipment, but hydrogen cannot be used efficiently. When there are users of hydrogen fuel equipment and users of existing gas combustion equipment on the consumer side, there is a need for a method for using mixed gas simply and efficiently.

The present invention has been made in consideration of the above facts, and an object of the present invention is to easily and efficiently utilize a mixed gas containing hydrocarbons and hydrogen as main components.

In the heat source device system according to claim 1, a mixed gas containing hydrocarbons and hydrogen as main components supplied from a gas conduit is supplied to the fuel electrode without being reformed, and the hydrogen in the mixed gas is used for a power generation reaction. A heat source that includes a fuel cell that generates electricity, a burner that burns fuel electrode off-gas discharged from the fuel electrode of the fuel cell, and a heat exchanger that exchanges heat between the combustion heat of the burner and a fluid to be heated. It is equipped with a machine and.

In the heat source device system according to claim 1, the mixed gas containing hydrocarbons and hydrogen as main components from the gas pipe is supplied to the fuel electrode of the fuel cell without being reformed, and in the fuel cell, the hydrogen in the mixed gas is supplied to the fuel electrode of the fuel cell. Used for power generation. The fuel electrode off-gas that is discharged from the fuel electrode without being used for power generation is used for combustion in the burner of the heat source equipment, and heat is exchanged between the combustion heat from the burner and the fluid to be heated in the heat exchanger. The target fluid is heated.

According to the heat source device system according to the first aspect, hydrogen in the mixed gas is used in the fuel cell, and unused hydrocarbons, hydrogen, etc. are used in the heat source device. Therefore, compared to the case where hydrogen and hydrocarbons are combusted and utilized only by a heat source device, the amount of energy obtained relative to the supplied energy is increased, and the mixed gas can be used efficiently.

In addition, hydrogen and hydrocarbons are used without separation from the mixed gas, and the mixed gas supplied to the fuel cell is not reformed, so a separation device or reformer is not required, and the configuration can be simplified. can.

The heat source device system according to claim 2 includes an electric heater that is disposed upstream of the heat exchanger in the flow path of the heating target fluid and heats the heating target fluid, and the electric heater is configured to heat the heating target fluid. Power is supplied to the user's power consumption and the surplus is supplied to the electric heater.

According to the heat source device system according to the second aspect, the surplus of the electric power generated by the fuel cell is supplied to the electric heater, and the fluid to be heated is heated upstream of the heat exchanger. Thereby, surplus power can be used efficiently.

The heat source device system according to claim 3 includes a fuel supply unit that supplies the mixed gas to the fuel cell, and a fuel supply unit configured to supply the mixed gas to the fuel electrode only when there is an operation request for the heat source device. A control section that controls the supply section.

According to the heat source device system according to the third aspect, the mixed gas is supplied to the fuel electrode only when the operation of the heat source device is requested. Here, "when there is an operation request for the heat source device" means a case where there is an operation request for the heat source device and the heat source device is operating in response to the request. Therefore, a situation where only the fuel cell is operated and the heat source machine is not operated does not occur, and the fuel electrode off-gas containing hydrocarbons and unused hydrogen discharged from the fuel cell can be appropriately processed in the heat source machine. .

In the heat source device system according to claim 4, when the control unit determines that the continuous operation time of the heat source device is equal to or longer than a predetermined power generation time, the control unit controls the power generation operation of the fuel cell so that the power generation operation of the fuel cell is started. Control the fuel cell.

According to the heat source device system according to claim 4, when it is determined that the continuous operation time of the heat source device is longer than the predetermined power generation time, the power generation operation of the fuel cell is started. The power generation operation of the fuel cell can be suppressed.

A method for operating a heat source system according to claim 5 includes supplying a mixed gas containing hydrocarbons and hydrogen as main components supplied from a gas conduit to a fuel electrode of a fuel cell without reforming the hydrogen in the mixed gas. The fuel electrode off-gas discharged from the fuel electrode of the fuel cell is sent to a heat source device, and the fluid to be heated is heated with the combustion heat combusted by the burner of the heat source device.

In the heat source device system operating method according to claim 5, electricity is generated using hydrogen in a mixed gas containing hydrocarbons and hydrogen supplied from a gas pipe, and fuel electrode off-gas discharged from the fuel electrode of the fuel cell is used in the heat source device. burner, and the combustion heat heats the fluid to be heated. Therefore, the mixed gas can be used more efficiently than when hydrogen and hydrocarbons are burned and used only by the heat source device.

Further, since the mixed gas supplied to the fuel cell is not reformed, a reformer is not required, and the structure can be simplified.

According to the heat source device system and the heat source device system operating method according to the present invention, a mixed gas containing hydrocarbons and hydrogen as main components can be used easily and efficiently.

FIG. 1 is a configuration diagram of a heat source device system according to a first embodiment. FIG. 2 is a control-related configuration diagram of the heat source device system according to the first embodiment. It is a flowchart of power generation control processing. FIG. 2 is a configuration diagram of a heat source device system according to a second embodiment.

<First embodiment>
A first embodiment of the present invention will be described with reference to the drawings.

The heat source device system 10A is a system for heating a fluid to be heated such as water, which is installed in a user's home or an apartment complex, and is a device that serves as a heat source for hot water supply equipment, hot water floor heating equipment, etc. . FIG. 1 schematically shows the main configuration of a heat source device system 10A according to an embodiment of the present invention. A heat source device system 10A according to an embodiment of the present invention includes a power generation unit 12 and a heat source device 30 as main components.

Mixed gas is supplied to the heat source system 10A 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 for example, a mixture of city gas and hydrogen can be used. Further, as an example, the hydrogen concentration in the mixed gas can be set to about 0.1% to 10%, and the methane concentration can be set to about 90% to 99.9%. A fuel supply pipe P1 is provided branching off from the gas conduit G, and the mixed gas is supplied to the heat source system 10A via the fuel supply pipe P1.

The power generation unit 12 is a device that generates power using hydrogen in 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 .

The fuel cell stack 20 is a cell stack including a plurality of stacked fuel cells. The fuel cell stack 20 is an example of a fuel cell in the present invention, and each fuel cell includes an electrolyte layer (not shown), a fuel electrode 20A and an air electrode laminated on the front and back surfaces of the electrolyte layer, respectively. 20B. 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). . This embodiment will be explained using PEFC as an example.

A fuel supply pipe P1 is connected to the inlet side of the fuel electrode 20A, and an air supply pipe P2 is connected to the inlet side of the air electrode 20B. The fuel supply pipe P1 is provided with a fuel supply blower 24 and a desulfurizer 14 in this order from the upstream side. The fuel supply blower 24 sends out the mixed gas toward the fuel electrode 20A at a specified flow rate. The desulfurizer 14 removes sulfur components as an odorant in the mixed gas. The mixed gas from which the sulfur component has been removed contains hydrogen and methane, and is supplied to the fuel electrode 20A of the fuel cell stack 20 without being reformed. The air supply pipe P2 is provided with an air supply blower 22, and the air supply blower 22 supplies air to the air electrode 20B.

A fuel electrode off-gas pipe P3 is connected to the exit side of the fuel electrode 20A, and an air electrode off-gas pipe P4 is connected to the exit side of the air electrode 20B. The downstream end of the fuel electrode off-gas pipe P3 is connected to a burner 32 of the heat source device 30, which will be described later. The air electrode off-gas discharged from the air electrode 20B is dissipated into the atmosphere from the air electrode off-gas pipe P4. The fuel electrode off-gas discharged from the fuel electrode 20A is supplied to the burner 32 via the fuel electrode off-gas pipe P3.

A power conditioner 26 is electrically connected to the fuel cell stack 20 . The power conditioner 26 controls the power generation output by the fuel cell stack 20 and supplies power to the user.

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

A fuel electrode off-gas pipe P3 is connected to the burner 32, and fuel electrode off-gas discharged from the fuel electrode 20A of the fuel cell stack 20 is supplied thereto. Burner 32 is located adjacent to heat exchanger 34 . The burner 32 burns the combustible components in the fuel electrode off-gas and heats the clean water supplied to the heat exchanger 34 using the combustion heat.

The tap water heated by the heat exchanger 34 is sent out from the pipe P7 and is supplied to hot water supply and floor heating. Combustion exhaust gas from the burner 32 is discharged from the exhaust gas pipe P6.

FIG. 2 shows a schematic block diagram of the control system of the heat source device system 10A. The heat source device system 10A is provided with a controller 40, and the power generation unit 12 and the heat source device 30 are controlled by the controller 40.

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, and an input/output interface (I/F) 44. A storage unit 45 is provided.

The CPU 41, ROM 42, RAM 43, and I/F 44 are each connected via a bus 46. Each functional unit including the storage unit 45 is connected to the I/F 44 . Each of these functional units can communicate with the CPU 41 via the I/F 44.

As the storage unit 45, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), a flash memory, or the like is used. The storage unit 45 stores a control program for controlling each part of the heat source device system 10A and various data. Note that this control program and various data may be stored in the ROM 42.

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 process.

The power generation condition information I is a condition for performing power generation operation in the power generation unit 12. In this embodiment, the operation of the heat source device 30 is a condition for power generation operation, and when there is an input from the operation panel 50 to start floor heating or to start filling the bathtub, the hot water supply time is set for a predetermined time. If it becomes T or more, one of the following conditions is set. The predetermined time T is set, for example, from 10 seconds to 20 seconds, which is shorter than for floor heating or bathtub filling, and is shorter than floor heating or bathtub filling, but it is a time that increases the user's hot water usage time to a certain extent. Can be set. The floor heating time, the bathtub filling time, and the predetermined time T or longer are examples of the power generation possible time of the present invention.

The controller 40 is connected to the air supply blower 22, the fuel supply blower 24, the power conditioner 26, the burner 32, the operation panel 50, and the like. The operation panel 50 includes a display, a lamp, a switch, etc., allows the user to input various instructions, and displays the status of the heat source system 10A.

Next, the operation of the heat source device system 10A will be explained.

When the user turns on the power source of the heat source device system 10A from the operation panel 50, the controller 40 executes the power generation control process shown in FIG. 3.

In step S10, it is determined whether there is an instruction to drive the heat source device 30, and if the determination is affirmative, driving of the heat source device 30 is started in step S12. If the determination is negative, the system waits until an instruction to drive the heat source device is given. The drive instruction for the heat source device 30 is given by a user's input from the operation panel 50 (starting floor heating, filling the bathtub, etc.), or by issuing tap water exceeding the minimum ignition flow rate.

When the heat source device 30 starts driving, the fuel supply blower 24 is driven, and the mixed gas is passed through the desulfurizer 14 and the fuel electrode 20A of the fuel cell stack 20 without reforming from the gas conduit G to the burner of the heat source device 30. 32. Then, the mixed gas (fuel electrode off-gas) is combusted in the burner 32, and water, which is a fluid to be heated and supplied to the heat exchanger 34, is heated by the combustion heat. In this embodiment, water is used as an example of the fluid to be heated, but other fluids such as antifreeze (in the case of floor heating) may be used.

In step S14, it is determined whether the power generation conditions are satisfied. Whether or not the power generation conditions are satisfied is determined by whether or not the power generation condition information I stored in the storage unit 45 is satisfied. In the present embodiment, the determination is made when there is an input from the operation panel 50 to start floor heating, when there is an input to start filling the bathtub, and when the hot water supply time is longer than the predetermined time T after tap water starts flowing. Affirmed.

If it is determined in step S14 that the power generation conditions are satisfied, an instruction to start power generation operation in the power generation unit 12 is output in step S16. 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 generating power from the fuel cell stack 20. As a result, the hydrogen in the mixed gas supplied to the fuel cell stack 20 is used for the power generation reaction and consumed, and the fuel electrode off-gas after hydrogen consumption is supplied to the burner 32. In the burner 32, fuel electrode off-gas after hydrogen consumption in the fuel cell stack 20 is burned.

Next, in step S18, the system waits until there is an instruction to stop the heat source device 30, and if there is an instruction to stop the heat source device 30, an instruction to stop the heat source device 30 is output in step S20, and in step S22, the power generation unit 12 power generation operation will be stopped.

In step S24, it is determined whether there is an instruction to stop the heat source device system 10A, and if the determination is affirmative, this process is ended. If there is no instruction to stop the heat source device system 10A, the process returns to step S10 and the above process is repeated.

In the heat source device system 10A of this embodiment, hydrogen in the mixed gas is used for power generation 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 device 30. Therefore, the mixed gas can be used more efficiently than when the mixed gas containing hydrogen and methane is combusted and used only by the burner 32 of the heat source device 30.

Furthermore, since hydrogen is included in the mixed gas supplied to the fuel cell stack 20, a reformer is not required and the configuration can be simplified.

Note that in this embodiment, the mixed gas is supplied to the fuel cell only when there is an operation request for the heat source device 30, but the mixed gas is supplied to the fuel cell when the heat source device 30 is not in operation, and the power generation unit 12 is operated to generate power. You may do so. In this case, a combustor or the like is provided to appropriately process the fuel electrode off-gas containing combustible components discharged from the fuel cell stack 20. As in this embodiment, by supplying the mixed gas to the fuel cell only when there is an operation request for the heat source device 30, the fuel electrode off-gas containing combustible components discharged from the fuel cell stack 20 can be discharged to the outside. The heat source device 30 can appropriately process the heat source without having to do so. Note that the supply of the mixed gas to the fuel electrode 20A here includes the case where the power generation operation of the power generation unit 12 is not performed.

Furthermore, in the present embodiment, when it is determined that the continuous operation time of the heat source device 30 is longer than the floor heating time, the bathtub filling time, and the predetermined time T, the power generation operation of the fuel cell stack 20 is started. Therefore, inefficient power generation operation of the fuel cell stack 20 can be suppressed. Note that it is not necessarily necessary that the power generation operation of the fuel cell stack 20 is started when it is determined that the continuous operation time of the heat source device 30 is longer than the floor heating time, bathtub filling time, and predetermined time T. Alternatively, the power generation operation of the fuel cell stack 20 may be started at the same time as the heat source device 30 is driven.

<Second embodiment>
Next, a second embodiment of the present invention will be described. In this embodiment, parts similar to those in the first embodiment are shown with the same reference numerals, and detailed explanation thereof will be omitted.

As shown in FIG. 4, the heat source system 10B of this embodiment differs from the first embodiment mainly in that it includes a heater 52. The heater 52 is an electric heater, and is connected to a water supply pipe P5. The water from the water supply pipe P5 is heated by the heater 52 and sent to the heat exchanger 34.

The power conditioner 26 supplies power to the user according to the load power, and when surplus power is generated, supplies the surplus power to the heater 52.

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

Although the embodiments of the present invention have been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be implemented with various modifications other than the above without departing from the spirit thereof. be.

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

Claims (5)

A fuel cell in which a mixed gas containing hydrocarbons and hydrogen as main components supplied from a gas conduit is supplied to a fuel electrode without being reformed, and the hydrogen in the mixed gas is used in a power generation reaction to generate electricity;
a heat source device comprising: a burner that burns fuel electrode off-gas discharged from the fuel electrode of the fuel cell; and a heat exchanger that exchanges heat between the combustion heat of the burner and a fluid to be heated;
A heat source system equipped with an electric heater that is disposed upstream of the heat exchanger in the flow path of the heating target fluid and heats the heating target fluid;
The 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 device system according to claim 1. a fuel supply section that supplies the mixed gas to the fuel cell;
a control unit that controls the fuel supply unit so that the mixed gas is supplied to the fuel electrode only when there is an operation request for the heat source device;
The heat source device system according to claim 1 or claim 2, comprising: The control unit controls the fuel cell so that power generation operation of the fuel cell is started when it is determined that the continuous operation time of the heat source device is equal to or longer than a predetermined power generation time.
The heat source device system according to claim 3. A mixed gas containing hydrocarbons and hydrogen as main components supplied from a gas pipe is supplied to a fuel electrode of a fuel cell without being reformed, and the hydrogen in the mixed gas is used to generate electricity,
sending fuel electrode off-gas discharged from the fuel electrode of the fuel cell to a heat source device, and heating a fluid to be heated with combustion heat combusted by a burner of the heat source device;
How to operate the heat source system.