JP7306851B2 - fuel cell device - Google Patents

Description

The present disclosure relates to fuel cell devices.

A solid oxide fuel cell (SOFC) is known that generates power using a fuel gas that is a hydrogen-containing gas and air that is an oxygen-containing gas. In a fuel cell device including such a fuel cell, energy is efficiently used by supplying hot water using exhaust heat generated by power generation. A fuel cell device includes piping through which a heat medium such as water flows for hot water supply. For example, when the temperature of the surrounding environment becomes low while the fuel cell device is stopped, the heat medium remaining in the pipe may freeze. Freezing of the heat medium causes damage to the flow path and reduces the durability of the fuel cell device.

In the heat recovery system described in Patent Document 1, for the purpose of preventing freezing, in order to discharge the water in the heat recovery path including the hot water storage tank, after supplying water to the sealed hot water storage tank and compressing the air, The heat recovery path is open to the atmosphere, and the water in the path is forcibly discharged by air pressure.

JP 2008-202887 A

In the heat recovery system of Patent Document 1, no consideration is given to discharging the water in the flow path that supplies water to the hot water storage tank (heat storage tank) in order to prevent freezing. Therefore, there is a possibility that the remaining water freezes and the flow path is damaged or the durability is lowered.

The fuel cell device of the present disclosure includes a fuel cell module including cells that generate power using a fuel gas and an oxygen-containing gas;
a heat storage tank that stores a heat medium that exchanges heat with exhaust heat from the fuel cell module;
a water supply channel that connects a water supply source that supplies water from the outside to the heat storage tank and the heat storage tank;
a heat medium water supply valve provided in the water supply flow path;
a drainage channel connected between the heat medium water supply valve in the water supply channel and the water supply source;
a water level sensor that detects the water level of the heat storage tank;
a control device for controlling the operation of the fuel cell device,
After the water draining mode of the fuel cell device is started, the control device notifies the abnormality when an abnormality related to the water level of the heat storage tank is detected, and opens the heat medium feed valve when the abnormality is not detected.

According to the fuel cell device of the present disclosure, it is possible to reduce the residual amount of water in the water supply channel in the water draining mode, reduce damage to the channel due to water freezing, and prevent deterioration in durability. can be suppressed.

It is a figure showing a schematic structure of a fuel cell device of an embodiment. 1 is a perspective view showing the configuration of a fuel cell device inside an exterior case; FIG. It is a schematic diagram which shows the water-supply-and-drainage channel of a thermal storage tank. It is a flow chart which shows drainage control.

A fuel cell device according to an embodiment of the present disclosure will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fuel cell device according to an embodiment, and FIG. 2 is a perspective view showing the configuration of the fuel cell device within an exterior case. FIG. 3 is a schematic diagram showing a water supply/drainage channel of a heat storage tank. FIG. 4 is a flow chart showing drain control.

The fuel cell device 100 of the embodiment includes a fuel cell module 1 that generates power using fuel gas and air, a heat storage tank 3, a water supply channel S that supplies water to the heat storage tank 3, and a water supply channel S provided with: a heat medium water supply valve Vs; a branch drainage channel Ds branching from the water supply channel S; The fuel cell device 100 is configured to be able to operate by appropriately switching between a plurality of types of operation modes. The operation modes of this embodiment include at least an operation mode in which power generation is performed, a stop mode in which power generation is stopped, and water as a heat medium in the heat storage tank 3 and water in the water supply and drainage flow path of the heat storage tank 3 for the purpose of preventing freezing. A drain mode is included to drain water out of the device. The operation mode may further include a rated operation mode, a partial load operation mode, and the like.

As indicated by symbol HC1 in FIG. 1, a first heat recovery system that is an exhaust heat recovery system having a first heat exchanger 2, a heat storage tank 3, a cooler 5, a heat medium pump P2, and a circulation flow path connecting these Equipped with a circulation system (heat cycle). As indicated by symbol HC2 in FIG. 1, a second heat exchanger 4 (also referred to as a tap water heat exchanger), a circulation pump P3 that circulates the heat medium from the heat storage tank 3 described above, and a flow path pipe that connects these and a second heat circulation system, which is an exhaust heat recovery system. Using the high-temperature heat medium stored in the heat storage tank 3, water such as tap water supplied from the outside through the supply flow path Kin is heated by the second heat exchanger 4, and heated. Water is delivered to a reheating device, such as an external water heater, via a delivery channel Kout.

The fuel cell module 1 includes a fuel cell 11 and a reformer 12 accommodated in a container 10 . The fuel cell 11 may be of any type as long as it generates power using fuel gas and air, and may have, for example, a cell stack structure in which a plurality of fuel cells are arranged. A fuel cell 11 having a cell stack structure is constructed by fixing the lower end of each fuel cell to a manifold with an insulating bonding material such as a glass sealing material. Further, fuel gas and air required for power generation of the fuel cell 11 are supplied from the lower end side of the fuel cell. In the fuel cell 11, columnar fuel cells having a gas flow path through which gas flows along the longitudinal direction are arranged in an upright state, and electricity is supplied between adjacent fuel cells through a current collecting member. are connected in series. Various fuel cells are known as fuel cells, but solid oxide fuel cells may be used when a partial load operation mode is included as an operation mode.

The water supply channel S includes a channel pipe that connects the heat storage tank 3 and a water supply source that supplies water from the outside to the heat storage tank 3 . When the operation of the fuel cell device 100 is started, the water supply path S is used to supply water as a heat medium from the water supply source to the heat storage tank 3 in order to circulate the first thermal circulation system. The water supply source may be, for example, the water supply. The water supply channel S is connected to the upper portion of the heat storage tank 3, for example, to the top plate portion. A water supply valve V1 is provided at the end of the water supply passage S on the water supply source side. When the water supply valve V1 is opened, tap water is supplied from the water supply source to the water supply passage S, and when the water supply valve V1 is closed, the supply of tap water is stopped. In this embodiment, the opening and closing of the water supply valve V1 is performed manually, and the water supply valve V1 is open during operation.

A heat medium water supply valve Vs is provided in the water supply flow path S between the heat storage tank 3 and the water supply valve V1. When the heat medium water supply valve Vs is opened while the water supply valve V1 is open, tap water flowing through the water supply flow path S is supplied to the heat storage tank 3 . When the heat medium feed valve Vs is closed, tap water stops flowing through the heat medium feed valve Vs. The heat medium feed valve Vs is composed of, for example, an electromagnetic valve, and is opened and closed according to an electric signal output from the control device 30 . During operation, when there is no need to supply tap water to the heat storage tank 3, the heat medium water supply valve Vs is controlled to be closed. The heat medium water supply valve Vs is positioned, for example, below the connection position of the water supply passage S to the heat storage tank 3 and above the water supply source (water supply valve V1).

A branch drainage channel Ds, which is a drainage channel branching from the water supply channel S, is connected to the water supply channel S between the heat medium water supply valve Vs and the water supply valve V1. A branch drain valve V2 is provided in the branch drain flow path Ds. When the branch drain valve V2 is opened, among the water flowing through the water supply channel S, the water that has flowed into the branch drain channel Ds is drained to the outside. When the branch drain valve V2 is closed, the water in the branch drain channel Ds is not drained. In this embodiment, the opening and closing of the branch drain valve V2 is performed manually, and the branch drain valve V2 is closed during operation.

In the water supply channel S, a branch channel branched from the water supply channel S and connected to the reforming water tank 6 described later may be provided between the heat medium water supply valve Vs and the water supply valve V1. In this case, the supply of water to the reforming water tank 6 can be adjusted by providing a valve also in the branch channel. Further, by adjusting the position of the reformed water tank 6 and the position of the water discharged from the reformed water tank 6, it is possible to easily drain the branch flow path.

A tank drainage channel D is connected to the lower portion of the heat storage tank 3 . A tank drain valve V3 is provided at the end of the tank drain flow path D opposite to the heat storage tank 3 . When the tank drain valve V3 is opened, the heat medium (water) stored in the heat storage tank 3 is drained to the outside through the tank drain flow path D. When the tank drain valve V3 is closed, the drain from the tank drain channel D stops. In this embodiment, opening and closing of the tank drain valve V3 is performed manually, and the tank drain valve V3 is closed during operation.

The heat storage tank 3 is provided with a water level sensor for monitoring the amount of heat medium stored in the tank. The water level sensors include a low water level sensor LS1 that detects a relatively low water level indicating the minimum amount of water required for operation of the fuel cell device, and a high water level sensor LS1 that detects a relatively high water level indicating the full water level of the heat storage tank 3. and a sensor LS2.

Exhaust gas discharged from the fuel cell module 1 as a result of power generation by the fuel cell 11 is heat-exchanged in the first heat exchanger 2 between a heat medium such as water or a refrigerant flowing through the first heat exchanger 2 . be. At this time, water contained in the exhaust gas is condensed to produce condensed water. The resulting condensed water is collected through the condensed water flow path C and stored in the reforming water tank 6.

Exhaust gas from which moisture has been removed is discharged outside the fuel cell device through an exhaust gas passage E. The reforming water stored in the reforming water tank 6 is supplied to the reformer 12 in the fuel cell module 1 through the reforming water flow path R and the reforming water pump P1, and the water vapor of the raw fuel gas is supplied. Used for modification.

Air used for power generation in the fuel cell module 1 is introduced into the fuel cell 11 by an air supply device 13 including a blower B2 and a pipe F as an air flow path. The raw fuel gas is introduced into the reformer 12 together with the reformed water passing through the reformed water passage R through the fuel gas pump B1 and the pipe G, which is the raw fuel gas passage.

The fuel cell device 100 may further include various components necessary for power generation, hot water supply, and the like. Each configuration shown above is an example, and is an arbitrary configuration other than the configuration required for drain control, which will be described later.

The fuel cell device 100 includes a power conditioner 20, a control device 30, an operation board 40 including a display device and an operation panel, etc. as auxiliary devices for assisting the power generation operation, in addition to the fuel cell module 1 and the like. The fuel cell device 100 is arranged in a case 50 composed of frames 51 and exterior panels 52 as shown in FIG. 2, for example.

The fuel cell system 100 then includes a controller 30, including at least one processor and memory devices, etc., to provide control and processing power to perform various functions, as described in detail below.

According to various embodiments, at least one processor may be implemented as a single integrated circuit or as multiple communicatively coupled integrated and/or discrete circuits. The at least one processor can be implemented according to various known techniques.

In one embodiment, a processor includes one or more circuits or units configured to perform one or more data computing procedures or processes, such as by executing instructions stored in associated memory. In other embodiments, the processor may be firmware, eg, discrete logic components, configured to perform one or more data computing procedures or processes.

According to various embodiments, the processor is one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits, digital signal processors, programmable logic devices, field programmable gate arrays, or any of these devices or Any combination of configurations or combinations of other known devices and configurations may be included to perform the functions described below.

The control device 30 is connected to a storage device and a display device (both not shown), various components and various sensors that constitute the fuel cell device 100, and controls the entire fuel cell device 100 including these functional units. control and manage; The control device 30 acquires a program stored in a storage device attached thereto and executes the program, thereby realizing various functions of each part of the fuel cell device 100 .

When transmitting control signals or various types of information from the control device 30 to other functional units or devices, the control device 30 and other functional units may be connected by wire or wirelessly. The control characteristic of this embodiment performed by the control device 30 will be described later. In this embodiment, the control device 30 operates various auxiliary devices such as the fuel gas pump B1 based on instructions and commands from an external device connected to the fuel cell device, and instructions and measured values from the various sensors described above. Control. In some cases, the illustration of connection lines connecting the control device 30 and each device and each sensor constituting the fuel cell is omitted in the drawing.

A storage device (not shown) can store programs and data. The storage device may also be used as a work area for temporarily storing processing results. A storage device includes a recording medium. The recording medium may include any non-transitory storage medium such as semiconductor storage media and magnetic storage media. Also, the storage device may include multiple types of storage media. The storage device may include a combination of a portable storage medium, such as a memory card, optical disk, or magneto-optical disk, and a storage reader. The storage device may include a storage device such as RAM (Random Access Memory) that is used as a temporary storage area.

Note that the control device 30 and the storage device of the fuel cell device can also be implemented as a configuration provided outside the fuel cell device 100 . Furthermore, it is also possible to implement as a control method including characteristic control steps in the control device 30 according to the present disclosure, or as a control program for causing a computer to execute the above steps.

The fuel cell device 100 can execute the drain mode after executing the stop mode to stop power generation. A maintenance worker instructs execution of the draining mode using the operation board 40 . If the user is permitted to drain the water, the water may be drained by a remote controller (not shown) provided at the user's home and communicating with the fuel cell device.

After instructing the drain mode, the maintenance worker manually closes the water supply valve V1, opens the branch drain valve V2, and opens the tank drain valve V3. Further, the control device 30 controls the heat medium feed valve Vs based on the water level of the heat storage tank 3 . In this embodiment, the heat medium water supply valve Vs is located below the connection position of the water supply passage S to the heat storage tank 3 and above the water supply valve V1.

The water in the heat storage tank 3 is drained from the tank drain valve V3 through the tank drain flow path D. Water between the heat medium water supply valve Vs and the water supply valve V1 in the water supply passage S is discharged from the branch water discharge valve V2 through the branch water discharge passage Ds. The water between the water supply valve Vs is not drained from the branch drain valve V2 because the heat medium water supply valve Vs is closed.

Therefore, after the water draining mode of the fuel cell device is started, the control device 30 notifies the abnormality when an abnormality related to the water level of the heat storage tank 3 is detected, and opens the heat medium feed valve Vs when the abnormality is not detected. If the manual operation of opening and closing the valve is erroneous, water draining does not progress normally and an abnormality relating to the water level is detected in the heat storage tank 3, and this is reported. If no abnormality is detected, water draining is progressing normally, so by opening the heat medium water supply valve Vs, water remaining in the water supply flow path S can be drained from the branch drain valve V2. . As a result, in the draining mode, the amount of water remaining in the water supply channel S can be reduced, and damage to the channel piping due to freezing can be reduced.

FIG. 4 is a flow chart showing drain control. In the flowchart, "step" is abbreviated as "S", and in the chart, "positive" (computer flag = 1) in judgment control is [Yes], and "no" (computer flag = 0 zero) is [ No].

After the fuel cell device 100 executes the stop mode to stop power generation, the water draining control is started when the maintenance worker instructs the execution of the water draining mode. If draining by the user is permitted, the draining mode may be executed according to the user's remote control operation. After instructing the drain mode, the maintenance worker manually closes the water supply valve V1, opens the branch drain valve V2, and opens the tank drain valve V3. When the drain control of this embodiment starts, the control device 30 starts monitoring the water level in the heat storage tank 3 . In the following description, the abnormality determination time, the water level sensor to be used, the type of valve, and the operation time can be appropriately set according to the size of the heat storage tank 3 .

At [S1], it is determined whether or not the low water level sensor LS1 of the heat storage tank 3 has detected the water level. If the low water level sensor LS1 has detected the water level [Yes], in [S2], it is determined whether or not the first predetermined time T1 has elapsed since the instruction to drain the water. If T1 has elapsed [Yes], the control device 30 notifies an error in [S2] and terminates the control. Here, when the low water level sensor LS1 detects the water level even after the first predetermined time T1 has elapsed, the operation to open the tank drain valve V3 is not performed, and the heat storage tank 3 is drained with the tank drain valve V3 closed. It is assumed that In this case, the maintenance operator should open the tank drain valve V3 upon notification of the error and execute the drain control from the operation board 40 again. If [No] that the first predetermined time T1 has not elapsed since the instruction to drain the water, the process returns to [S1] to monitor the water level. The first predetermined time T1 can be set to any time, such as 15 minutes.

If the low water level sensor LS1 does not detect the water level [No], in [S4], it is determined whether or not the duration of the low water level sensor LS1 continuously not detecting the water level is equal to or longer than the second predetermined time T2. If the duration time is T2 or longer [Yes], the control device 30 transmits an electric signal to the heat medium feed valve Vs to open the valve in [S5], and the heat medium feed valve Vs in [S6]. It is determined whether or not the third predetermined time T3 has passed after opening Vs. Here, by opening the heat medium feed valve Vs, the water between the heat storage tank 3 and the heat medium feed valve Vs is drained from the branch drain valve V2.

In [S4], if the duration time is less than T2 [No], return to [S1] to monitor the water level. The second predetermined time T2 can be set to any time that is shorter than or equal to the first predetermined time T1, and is, for example, 15 minutes. Although the third predetermined time T3 can also be set to any time, it is, for example, 30 seconds.

If [No] that T3 has not passed since the heat medium feed valve Vs was opened, in [S7], it is determined whether or not the low water level sensor LS1 of the heat storage tank 3 has detected the water level. If the low water level sensor LS1 has detected the water level [Yes], in [S8] the control device 30 sends an electrical signal to the heat medium feed valve Vs to instruct the valve to close, and in [S9] an error is detected. Notify and end control. Here, when the low water level sensor LS1 detects the water level before the third predetermined time T3 has passed since the heat medium feed valve Vs was opened, the work of closing the water supply valve V1 is not performed, and the heat medium feed valve Vs is closed. was opened, it is assumed that tap water was supplied from the water supply passage S to the heat storage tank 3 . In this case, the maintenance worker closes the water supply valve V1 upon notification of the error, and executes the water removal control from the operation board 40 again. If the low water level sensor LS1 does not detect the water level [No], the process returns to [S6] to monitor the water level.

By setting the second predetermined time T2 to be shorter than the first predetermined time T1, it is possible to shorten the time required for draining water. However, when the valve is manually operated as in the present embodiment, it is necessary to consider the valve operation time as the second predetermined time T2. Since the maintenance worker operates the valve after instructing the drain mode, if the valve operation time is not considered in the second predetermined time T2, the heat medium feed valve Vs is opened before the water supply valve V1 is closed. This is because the water will flow into the heat storage tank 3 .

If [Yes] after the third predetermined time T3 has elapsed since the heat medium feed valve Vs was opened, the drain control is terminated. As a result, water remaining in the water supply channel S can be drained from the branch drain valve V2.

In addition, since the heat medium feed valve Vs is kept open, for example, when the drain mode is instructed, the water stop valve V1 is not completely closed, and a small amount of water flows into the heat storage tank 3. If there is, the water level of the heat storage tank 3 rises with time. Therefore, when the water level rise in the heat storage tank 3 is observed even after the water draining control is finished, an error is reported and the execution of the water draining mode is urged again, so that the water draining can be reliably completed.

In this embodiment, the branch drain valve V2 and the tank drain valve V3 are valves that are manually opened and closed. can also obtain the same effect. In this case, [S0] for opening the branch drain valve V2 and the tank drain valve V3 is added before [S1].

1 fuel cell module 3 heat storage tank 30 control device Ds branch drain channel LS1 low water level sensor S water supply channel Vs heat medium water supply valve

Claims (4)

a fuel cell module including cells that generate electricity using a fuel gas and an oxygen-containing gas;
a heat storage tank that stores a heat medium that exchanges heat with exhaust heat from the fuel cell module;
a water supply channel that connects a water supply source that supplies water from the outside to the heat storage tank and the heat storage tank;
a heat medium water supply valve provided in the water supply flow path;
a drainage channel connected between the heat medium water supply valve in the water supply channel and the water supply source;
a water level sensor that detects the water level of the heat storage tank;
a controller for controlling the operation of the fuel cell device,
The control device detects an abnormality related to the water level of the heat storage tank in a draining mode for discharging water as a heat medium in the heat storage tank of the fuel cell device and water in the water supply channel to the outside of the device. A fuel cell device that notifies an abnormality in case of an abnormality and opens the heat medium water supply valve in order to drain water remaining in the water supply flow path if no abnormality is detected. The control device is
When an abnormality related to the water level of the heat storage tank is continuously detected for a first predetermined time period, the abnormality is reported, and when the abnormality related to the water level of the heat storage tank is not continuously detected for a second predetermined time period, the heat medium feed valve is opened. with
2. The fuel cell apparatus according to claim 1, wherein said second predetermined time period is less than or equal to said first predetermined time period. 2. When the water level of the heat storage tank exceeds a predetermined water level within a third predetermined time after the heat medium feed valve is opened, the control device closes the heat medium feed valve and notifies an abnormality. 3. or the fuel cell device according to 2. 4. The fuel cell device according to claim 3, wherein, if the water level of said heat storage tank does not exceed a predetermined water level even after said third predetermined time has passed, said heat medium feed valve is kept open and said draining mode is terminated. .

Images