JP6897301B2 - Fuel cell system - Google Patents

Description

The present invention relates to a fuel cell system including a reforming unit that reforms a raw material gas into a reforming gas using steam.

Conventionally, as this type of fuel cell system, a combustion part, a vaporization part, a reforming part, a tank for storing water, a supply passage for supplying water in the tank to the vaporization part, and a vaporization part in the supply passage A water sensor that detects the water level immediately before the inlet port, a pump as a water transport source, and a control unit that controls the pump have been proposed (see, for example, Patent Document 1). In this fuel cell system, the control unit rotates the pump in the reverse direction to return the water in the supply passage to the tank before the combustion unit ignites, empties the inside of the supply passage, and then rotates the pump in the forward direction to tank. The water inside is supplied to the supply passage, and the water level in the supply passage is adjusted to the fixed position immediately before the inlet port of the vaporizer while monitoring the actual water level in the supply passage based on the detection signal from the water sensor. To do. As a result, the timing of water supply to the vaporizer can be made more appropriate, and caulking of the reformed part (fuel carbonization phenomenon) due to insufficient reformed water and deterioration of catalyst activity (deterioration of performance) due to excessive reformed water can be suppressed. It is said that it can be done.

Japanese Unexamined Patent Publication No. 2012-133915

As described above, in the fuel cell system described in Patent Document 1, a water level sensor is provided immediately before the inlet port of the vaporization unit in order to supply water to the vaporization unit at an appropriate timing. However, water level sensors are generally expensive and increase the cost of fuel cell systems.

The main object of the fuel cell system of the present invention is to enable water supply to the vaporization unit at a more appropriate timing without using a water level sensor.

The fuel cell system of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The fuel cell system of the present invention
A fuel cell system including a fuel cell that generates electricity based on a reformed gas containing hydrogen and an oxidant gas.
A reforming unit that reforms the raw material gas into the reforming gas using steam and supplies it to the fuel cell.
A vaporization unit that vaporizes water and supplies it to the reforming unit,
A water tank to store water and
A water pipe connected to the vaporization unit and the water tank,
A fixed-quantity water pump installed in the water pipe that can feed liquid in both forward and reverse directions,
A combustion part that heats the reforming part and the vaporizing part by the heat of combustion,
When the system is started, the water is supplied to the vaporization unit after performing water level adjustment control for driving the water pump for a certain period of time so that the water level in the water pipe becomes a predetermined water level from the state where the water in the water pipe is empty. A control device that controls the water pump and
The gist is to prepare.

The fuel cell system of the present invention includes a reforming unit, a vaporizing unit, a water tank, a water pipe connected to the vaporizing unit and the water tank, a quantitative water pump provided in the water pipe, and combustion. It is provided with a combustion part that heats a reforming part and a vaporizing part by heat. Then, when the system is started, the water level adjustment control is performed to drive the water pump for a certain period of time so that the water level in the water pipe becomes a predetermined water level from the state where the water in the water pipe is empty. Since the water pump is a quantitative pump, the water level of the water pipe can be made constant by driving the water pump for a certain period of time from the state where the water in the water pipe is empty. Further, since the water pump can feed the liquid in both the forward and reverse directions, the water in the water pipe can be emptied by driving the water pump in the opposite direction. As a result, the water level of the water pipe can be set to a predetermined water level before the water is supplied to the vaporization unit without using the water level sensor, and the water supply to the vaporization unit can be performed at a more appropriate timing.

In such a fuel cell system of the present invention, the control device may control the water pump so that the water in the water pipe is emptied by liquid feeding in the reverse direction after the system is stopped. In this way, the inside of the water pipe can be emptied between the time the system is stopped and the time the system is started next time, so there is no risk of the water pipe freezing and the anti-freezing heater is not required. Can be done.

Further, in the fuel cell system of the present invention, the control device waits in a state where the drive of the water pump is stopped after performing the water level adjustment control, and is predetermined after the ignition of the combustion unit is started. At the timing when the standby time has elapsed, the driving of the water pump may be started to start supplying water to the vaporization unit. In this way, water can be supplied to the vaporization unit at an appropriate timing. In the fuel cell system of the present invention of this aspect, the temperature sensor for detecting the temperature of the vaporizing unit or the reforming unit is provided, and the control device is detected by the temperature sensor after starting water supply to the vaporizing unit. The waiting time may be changed based on the temperature. In this way, it is possible to supply water to the vaporization unit at a more appropriate timing when the system is started next time. Further, in the fuel cell system of the present invention of this aspect, the control device holds the standby time when the detected temperature is in an appropriate range, and shortens when the detected temperature is higher than the appropriate range. The waiting time may be changed so that when the detected temperature is lower than the appropriate range, the waiting time becomes longer. In the fuel cell system of the present invention of this aspect, the control device may stop the system when the detected temperature is in the abnormal range. In this way, it is possible to deal with an abnormality in the fuel cell system.

It is a block diagram which shows the outline of the structure of the fuel cell system 10 of this embodiment. It is a flowchart which shows an example of a system control routine. It is a flowchart which shows an example of a system control routine. It is explanatory drawing which shows the state of the change of the reformer temperature at the time of system startup. It is explanatory drawing which shows an example of the waiting time update map.

A mode for carrying out the present invention will be described.

FIG. 1 is a configuration diagram showing an outline of the configuration of the fuel cell system 10 of the present embodiment. As shown in FIG. 1, the fuel cell system 10 of the present embodiment includes a power generation unit 20 having a fuel cell stack 36 that generates power by being supplied with a fuel gas containing hydrogen and an oxidizing agent gas (air) containing oxygen. The hot water supply unit 100 has a hot water storage tank 101 that recovers and supplies hot water generated by the power generation of the power generation unit 20, and a control device 80 that controls the entire system.

The power generation unit 20 includes a vaporizer 32 that evaporates reformed water to generate water vapor and preheats a raw material fuel gas (for example, natural gas or LP gas), and a fuel gas containing hydrogen from the raw material fuel gas and water vapor (modified). A power generation module 30 including a reformer 33 for generating (quality gas), a fuel cell stack 36 for generating power by fuel gas and air, a raw fuel gas supply device 40 for supplying raw fuel gas to the vaporizer 32, and a raw fuel gas supply device 40. The air supply device 50 that supplies air to the fuel cell stack 36, the reforming water supply device 55 that supplies the reforming water in the reforming water tank 57 to the vaporizer 32, and the exhaust heat generated by the power generation module 30 are recovered. The exhaust heat recovery device 60 is provided. These are housed in a rectangular parallelepiped housing 22 that is long vertically.

The housing 22 is divided into two upper and lower chambers, a power generation module 30 is arranged in the upper chamber, and a raw fuel gas supply device 40, an air supply device 50, and a reforming water tank 57 are included in the lower chamber. A reformed water supply device 55, an exhaust heat recovery device 60, and the like are arranged. Further, the housing 22 is provided with an intake port 22a and an exhaust port 22b. A ventilation fan 24 for taking in outside air and ventilating the inside of the housing 22 is provided near the intake port 22a, and a combustible gas sensor 95 for detecting leakage of combustible gas is provided near the exhaust port 22b. There is.

The reformer 33 is configured by supporting a reforming catalyst (for example, a Ru or Ni-based catalyst) on a carrier such as ceramic, and steam reforms a mixed gas of raw material fuel gas and steam supplied from the vaporizer 32. It reforms into fuel gas (reforming gas) by a quality reaction. Inside the reformer 33, a temperature sensor 91 for detecting the temperature of the reformer 33 is provided.

The vaporizer 32, the reformer 33, and the fuel cell stack 36 constituting the power generation module 30 are housed in a box-shaped module case 31 formed of a heat insulating material. The vaporizer 32 and the reformer 33 are arranged above the fuel cell stack 36. The module case 31 is provided with a combustion unit 34 for starting the fuel cell stack 36, generating steam in the vaporizer 32, and supplying heat required for the steam reforming reaction in the reformer 33. Fuel off gas (anode off gas) and oxidant off gas (cathode off gas) that have passed through the fuel cell stack 36 are supplied to the combustion unit 34, and the mixed gas is ignited by the ignition heater 35 and burned to burn the fuel cell. The stack 36, the vaporizer 32, and the reformer 33 are heated. The module case 31 is provided with a temperature sensor 92 for detecting the temperature of the combustion unit 34. The combustion exhaust gas generated by the combustion of the fuel off gas and the oxidant off gas is supplied to the heat exchanger 62 via the combustion catalyst 37. The combustion catalyst 37 is an oxidation catalyst that reburns the fuel gas left unburned in the combustion unit 34 by a catalyst, and the combustion catalyst 37 is provided with a temperature sensor 93 for detecting the temperature.

The raw fuel gas supply device 40 has a raw fuel gas supply pipe 41 that connects the gas supply source 1 and the vaporizer 32. The raw fuel gas supply pipe 41 is provided with raw fuel gas supply valves (electromagnetic valves) 42, 43, orifices 44, raw fuel gas pump 45, and desulfurizer 46 in this order from the gas supply source 1 side. By driving the raw material fuel gas pump 45 with the supply valves 42 and 43 opened, the raw material fuel gas from the gas supply source 1 is passed through the desulfurizer 46 and supplied to the vaporizer 32. The raw material fuel gas supplied to the vaporizer 32 is supplied to the reformer 33 via the vaporizer 32 and reformed into the fuel gas. The raw material fuel gas supply valves 42 and 43 are dual valves connected in series. The desulfurization device 46 removes the sulfur content contained in the raw material fuel gas, and for example, a room temperature desulfurization method for removing the sulfur compound by adsorbing it on an adsorbent such as zeolite can be adopted. Further, a pressure sensor 47 for detecting the pressure of the raw material gas in the raw material gas supply pipe 41 is provided between the raw material gas supply valve 43 of the raw material gas supply pipe 41 and the orifice 44, and the orifice 44 and the orifice 44 are provided. A flow rate sensor 48 for detecting the flow rate of the raw material gas flowing through the raw material gas supply pipe 41 per unit time is provided between the raw material gas pump 45 and the raw material gas pump 45.

The air supply device 50 has an air supply pipe 51 that connects the filter 52 that communicates with the outside air and the fuel cell stack 36. The air supply pipe 51 is provided with an air blower 53, and by driving the air blower 53, air sucked through the filter 52 is supplied to the fuel cell stack 36. Further, the air supply pipe 51 is provided with a flow rate sensor 54 on the downstream side of the air blower 53 to detect the flow rate of air flowing through the air supply pipe 51 per unit time.

The reformed water supply device 55 has a reformed water supply pipe 56 that connects the reformed water tank 57 for storing the reformed water and the vaporizer 32. The reforming water supply pipe 56 extends upward from the reforming water tank 57 arranged in the lower chamber of the housing 22 and is connected to the vaporizer 32 arranged in the upper chamber of the housing 22. The reforming water supply pipe 56 is provided with a reforming water pump 58, and by driving the reforming pump 58, the reformed water in the reforming water tank 57 is supplied to the vaporizer 32. The reformed water supplied to the vaporizer 32 is converted into steam by the vaporizer 32 and used for the steam reforming reaction in the reformer 33. Further, the reformed water tank 57 is provided with a water purifier (not shown) for purifying the reformed water to be stored.

The reforming water pump 58 is configured as a motor-driven metering pump, and can supply liquid in both forward and reverse directions by switching the rotation direction of the pump motor. That is, the reforming water pump 58 can send the water in the reforming water tank 57 toward the vaporizer 32 by driving the pump motor in the forward rotation direction, and drives the pump motor in the reverse rotation direction. As a result, the water in the reforming water supply pipe 56 can be returned to the reforming water tank 57. The reforming water pump 58 has a high sealing property, and the water above and downstream of the reforming water pump 58 (on the vaporizer 32 side) in the reforming water supply pipe 56 is below and upstream of the reforming water pump 58. It suppresses leakage to (the reformed water tank 57 side). However, when a long time has passed after the operation of the fuel cell system 10 is stopped, the water in the reforming water supply pipe 56 leaks to the reforming water tank 57 side little by little due to the influence of gravity or the like, and the reforming water supply pipe It was confirmed that the water level in 56 was lowered.

The exhaust heat recovery device 60 has a circulation pipe 61 that connects a heat exchanger 62 to which combustion exhaust gas is supplied from the power generation module 30 and a hot water storage tank 101 for storing hot water to form a circulation path for hot water. A circulation pump 63 is provided in the circulation pipe 61. By driving the circulation pump 63, the hot water is heated by heat exchange between the hot water stored by the heat exchanger 62 and the combustion exhaust gas, and the heated hot water is stored. Water is stored in the hot water storage tank 101. The heat exchanger 62 is connected to the reforming water tank 57 via the condensed water supply pipe 66 and is connected to the outside air via the exhaust gas discharge pipe 67, and the combustion exhaust gas supplied to the heat exchanger 62 is By heat exchange with the hot water, the water vapor component is condensed and collected in the reformed water tank 57, and the remaining exhaust gas is discharged to the outside air through the exhaust gas discharge pipe 67.

The fuel cell stack 36 includes a solid oxide fuel cell having a solid electrolyte composed of an oxygen ion conductor, an anode provided on one surface of the solid electrolyte, and a cathode provided on the other surface of the solid electrolyte. It is configured as a laminated structure, and generates electricity by an electrochemical reaction between hydrogen in the fuel gas supplied to the anode and oxygen in the air supplied to the cathode. A power line 3 from the commercial power source 2 to the load 4 is connected to the output terminal of the fuel cell stack 36 via a power conditioner 71 including a DC / DC converter and an inverter, and DC power from the fuel cell stack 36. Is added to the AC power from the commercial power source 2 through voltage conversion and DC / AC conversion by the power conditioner 71, and is supplied to the load 4. A power supply board 72 is connected to a power line branched from the power conditioner 71. The power supply board 72 functions as a DC power source that supplies DC power to auxiliary machinery such as the raw material fuel gas supply valves 42 and 43, the raw material fuel gas pump 45, the air blower 53, the reformed water pump 58, and the circulation pump 63.

The control device 80 is configured as a microprocessor centered on the CPU 81, and in addition to the CPU 81, a ROM 82 for storing a processing program, a RAM 83 for temporarily storing data, and a flash memory as a rewritable non-volatile memory. It includes 84, a timer 85 for measuring time, and an input / output port (not shown). Various detection signals from the pressure sensor 47, the flow rate sensors 48, 54, the temperature sensors 91 to 93, the combustible gas sensor 95, and the like are input to the control device 80 via the input port. Further, from the control device 80, a drive signal to the fan motor of the ventilation fan 24, a drive signal to the solenoids of the raw fuel gas supply valves 42 and 43, a drive signal to the pump motor of the raw fuel gas pump 45, and a blower motor of the air blower 53. Drive signal to the pump motor of the reforming water pump 58, drive signal to the pump motor of the circulation pump 63, control signal to the inverter and DC / DC converter of the power conditioner 71, to the ignition heater 35. A drive signal, a display signal to the display panel 90 displaying various information, and the like are output via the output port.

Next, the operation of the fuel cell system 10 thus configured, particularly the operation at the time of system startup will be described. 2 and 3 are flowcharts showing an example of a system control routine executed by the CPU 81 of the control device 80. This routine runs when the system is allowed to boot.

When the system control routine is executed, the CPU 81 of the control device 80 starts the system startup process (S100). In the start-up process, for example, the corresponding auxiliary machinery is sequentially controlled, the initial operation is performed as a start-up preparation, the fuel adsorption process for adsorbing the fuel component to the desulfurizer 46 to suppress the air-fuel ratio deviation of the mixed gas, and the purging of the combustion unit 34 This is performed by sequentially executing the treatment, the off-gas ignition treatment in the combustion unit 34, the steam reforming treatment, and the like. Note that these start-up processes are examples, and the fuel adsorption process and the like may be omitted depending on the configuration of the fuel cell system 10 and the state of auxiliary machinery.

When the start-up process is started, the CPU 81 starts driving the reforming water pump 58 by rotating the pump motor at a predetermined rotation speed as one of the initial operations (S110). The reforming water pump 58 is driven by controlling the pump motor at a predetermined duty ratio in order to rotate the pump motor at a predetermined rotation speed. Then, when a certain time elapses (S120), the driving of the reforming water pump 58 is stopped (S130). The treatments of S110 to S130 are water level adjusting treatments for adjusting the water level in the reforming water supply pipe 56 to a predetermined water level (for example, the water level immediately before the inlet of the vaporizer 32), and the reforming water supply pipe 56 It is executed with the water inside empty. As described above, the reforming water pump 58 is a quantitative pump, and when the pump motor is driven at a constant rotation speed for a certain period of time, the same amount of water can always be sent. Therefore, the rotation speed (duty ratio) and drive time of the pump motor required for the water level in the reforming water supply pipe 56 to reach the predetermined water level from the empty state of the water in the reforming water supply pipe 56. By driving the pump motor at the obtained rotation speed (duty ratio) and driving time, the water level in the reforming water supply pipe 56 can be adjusted to a predetermined water level. it can. As a result, the expensive water level sensor can be omitted, so that the cost of the fuel cell system 10 can be reduced.

When the CPU 81 executes the initial operation, the fuel adsorption process, and the purge process, the CPU 81 then fills the power generation module 30 with the off-gas and drives the ignition heater 35 to start the off-gas ignition process (S140). Then, after the predetermined standby time tw has elapsed from the start of the ignition process (S150), the reforming water pump 58 is started to be driven to start supplying the reforming water to the vaporizer 32 (S). S160). Here, the standby time tw defines the supply timing of the reformed water. The standby time tw is stored in the flash memory 84 and can be updated by S240 described later.

Next, the CPU 81 inputs the reformer temperature from the temperature sensor 91 (S170), and determines whether or not the reformer temperature has reached a peak (S180). Then, when it is determined that the reformer temperature has reached the peak, the peak value is set to the determination temperature Tp (S190). FIG. 4 is an explanatory diagram showing a state of change in the reformer temperature when the system is started. As shown in the figure, when the off-gas is ignited, the reformer temperature rises due to the heating of the reformer 33 due to the rise in the internal temperature of the power generation module 30 due to the off-gas combustion, and the reformer water is introduced into the reformer 33. When it is done, the heat is taken away by the evaporation and it descends. Then, when the steam reforming reaction, which is an endothermic reaction, is started, each element of the steam reforming reaction, the evaporation of the reformed water, and the heating of the reformer 33 by off-gas combustion is balanced, and a stable state is reached. The reformer temperature reaches a peak just before the off-gas is ignited and the reforming water is introduced into the reformer 33, and the reformer temperature at that time is set to the determination temperature Tp. In the determination of S180, for example, the average value of the reformer temperature detected by the temperature sensor 91 during a predetermined time is calculated, and the average value of the reformer temperature calculated last time is calculated two times before. When the average value of the reformer temperature calculated this time is higher than the average value of the pawnbroker temperature and lower than the average value of the reformer temperature calculated last time, it is determined that the reformer temperature has reached the peak. It can be done by doing.

When the determination temperature Tp is set, the CPU 81 determines whether or not the determination temperature Tp is within the abnormality range including the reformer high temperature abnormality range and the reformer low temperature abnormality range (S200). Here, in the reformer high temperature abnormal range, the timing of supplying the reformed water to the reformer 33 is too late, and the reformer 33 becomes abnormally high temperature due to the shortage of the reformed water, and the reformer 33 is caulked (fuel). It is a temperature range in which a carbonization phenomenon) may occur. Further, the reformer low temperature abnormal range is a temperature range in which the reformer is supplied to the reformer 33 at an excessively early timing, and the reforming catalyst may deteriorate in activity (performance deteriorate) due to excessive reforming water. When it is determined that the determination temperature Tp is within the abnormal range (in either the reformer high temperature abnormal range or the reformer low temperature abnormal range), the fuel cell system 10 is abnormally stopped (S210) and displayed. A warning message indicating that an abnormality has occurred is displayed on the panel 90 (S220), and the system control routine is terminated. On the other hand, if it is determined that the determination temperature Tp is not within the abnormal range (not within either the reformer high temperature abnormal range or the reformer low temperature abnormal range), then the determination temperature Tp is within the appropriate range. Whether or not it is determined (S230). Here, the appropriate range is a temperature range in which the timing of supplying the reforming water to the reformer 33 is appropriate, there is no excess or deficiency in the reforming water, and the reaction of the reforming catalyst is satisfactorily performed. When it is determined that the determination temperature Tp is not within the abnormal range but not within the appropriate range, the standby time tw is updated based on the determination temperature Tp and the standby time update map and saved in the flash memory 84 (S240). If it is determined that the determination temperature Tp is within the appropriate range, the processing of S240 is skipped. FIG. 5 is an explanatory diagram showing an example of a waiting time update map. As shown in the figure, the standby time update map updates the standby time tw so that the higher the determination temperature Tp is higher than the upper limit of the appropriate range, the shorter the standby time tw is, and the determination temperature Tp is lower than the lower limit of the appropriate range. Occasionally, the relationship between the determination temperature Tp and the standby time tw is determined so that the lower the value, the longer the standby time tw. In the map for updating the standby time, the standby time tw is not changed within the appropriate range of the determination temperature Tp, which is a dead zone.

Then, when the steam reforming process is executed, the CPU 81 starts the power generation process (S250). The power generation process is performed by inputting a system requirement (load command of load 4) and controlling the raw fuel gas supply device 40, the air supply device 50, and the reforming water supply device 55 according to the input system requirement. It is done. Specifically, the control of the raw material fuel gas supply device 40 sets the target flow rate to be supplied by the raw material fuel gas supply device 40 based on the input system requirement, and is detected by the set target flow rate and the flow rate sensor 48. The duty ratio is set by feedback control based on the deviation from the flow rate, and the pump motor of the raw fuel gas pump 45 is controlled based on the set duty ratio. The control of the air supply device 50 sets a target flow rate to be supplied by the air supply device 50 so as to have a predetermined ratio (air-fuel ratio) with respect to the target flow rate of the raw material fuel gas, and the set target flow rate and the flow rate sensor 54 control the air supply device 50. The duty ratio is set by feedback control based on the deviation from the detected flow rate, and the blower motor of the air blower 53 is controlled based on the set duty ratio. The control of the reforming water supply device 55 sets the target water amount to be supplied by the reforming water supply device 55 based on the input system requirement amount, sets the duty ratio so as to reach the set target water amount, and sets the duty. This is done by controlling the pump motor of the reforming water pump 58 based on the ratio.

When the system stop is requested (S260) during the power generation process, the CPU 81 stops the system (S270) and stops the reforming water pump 58 when the system is stopped (S280). Then, the reforming water pump 58 (pump motor) is driven in the reverse rotation direction so that the water in the reforming water supply pipe 56 returns to the reforming water tank 57 side (S290), and the water in the reforming water supply pipe 56 is driven. When a certain period of time required for the empty state has elapsed (S300), the reforming water pump 58 is stopped (S310), and the system control routine is terminated. In this way, by leaving the water in the reforming water supply pipe 56 empty when the system is stopped, the water level is adjusted in the state where the water in the reforming water supply pipe 56 is empty at the next system startup. The process can be executed. In this case, there is no possibility that the reforming water supply pipe 56 freezes between the time the system is stopped and the time the system is started next time, and the antifreezing heater can be eliminated.

The fuel cell system 10 of the embodiment described above performs water level adjustment control for driving the reforming water pump 58 for a certain period of time from a state where the water in the reforming water supply pipe 56 is empty when the system is started. Since the reforming water pump 58 is a quantitative pump, the reforming water pump 58 can be driven for a certain period of time from an empty state in the reforming water supply pipe 56 without using a water level sensor. The water level in the quality water supply pipe 56 can be adjusted to a predetermined water level. Further, since the reforming water pump 58 can feed liquid in both forward and reverse directions, the water in the reforming water supply pipe 56 is emptied by driving the reforming water pump 58 in the opposite direction. be able to. As a result, it becomes possible to supply water to the vaporizer 32 at a more appropriate timing without using the water level sensor.

After the system is stopped, the fuel cell system 10 of the embodiment reversely drives the reforming water pump 58 to empty the water in the reforming water supply pipe 56. As a result, at the next system startup, the water level adjustment process can be executed while the water in the reforming water supply pipe 56 is empty. Further, there is no possibility that the reforming water supply pipe 56 freezes between the time when the system is stopped and the time when the system is started next time, and the antifreezing heater can be eliminated.

The fuel cell system 10 of the embodiment waits in a state where the driving of the reforming water pump 58 is stopped after performing the water level adjustment control, and when the standby time tw elapses after the ignition of the combustion unit 34 is started. In addition, the reforming water pump 58 is started to be driven to start supplying water to the vaporizer 32 (reformer 33). Further, the reformer 33 is provided with the temperature sensor 91, and after starting the supply of water to the vaporizer 32, the standby time tw is changed by the determination temperature Tp based on the reformer temperature detected by the temperature sensor 91. As a result, the supply timing of the reforming water can be brought closer to an appropriate timing at the next system startup. Further, when the determination temperature Tp is within the abnormal range (within either the reformer high temperature abnormal range or the reformer low temperature abnormal range), the fuel cell system 10 is abnormally stopped, so that the occurrence of an abnormality is quick. Can be dealt with.

In the embodiment, the reforming water pump 58 is driven in the reverse rotation to leave the inside of the reforming water supply pipe 56 empty after the system is stopped, but the present invention is not limited to this, and the water level at the time of system startup is not limited to this. Prior to the execution of the adjustment process, the reforming water pump 58 may be driven in a reverse rotation to empty the inside of the reforming water supply pipe 56.

In the embodiment, the standby temperature update map is provided with a dead zone in which the standby time tw is not changed in the determination temperature Tp, but the dead zone may not be provided.

In the embodiment, the waiting time tw is updated, but a predetermined fixed time may be used as the waiting time tw, and the waiting time tw may not be updated.

In the embodiment, the temperature sensor 91 is provided inside the reformer 33, and the standby time tw is updated based on the reformer temperature detected by the temperature sensor 91. However, the temperature sensor is inside the vaporizer 32. The standby time tw may be updated based on the vaporizer temperature detected by the temperature sensor. Also in this case, the reformer temperature may be replaced with the vaporizer temperature, and the processes of S170 to S240 of the system control routine may be executed.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the reformer 33 corresponds to the reformer, the vaporizer 32 corresponds to the vaporizer, the reformer water tank 58 corresponds to the water tank, and the reformer water supply pipe 56 corresponds to the water pipe. The reforming water pump 58 corresponds to the water pump, the combustion unit 34 corresponds to the combustion unit, and the control device 80 corresponds to the control device. Further, the temperature sensor 91 corresponds to the temperature sensor.

Regarding the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for the embodiment to solve the problem is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the embodiment is the invention described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above using the embodiments, the present invention is not limited to these embodiments, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of fuel cell systems and the like.

1 gas supply source, 2 commercial power supply, 3 power line, 4 load, 10 fuel cell system, 20 power generation unit, 22 housing, 22a intake port, 22b exhaust port, 24 ventilation fan, 30 power generation module, 31 module case, 32 Vaporizer, 33 reformer, 34 combustion part, 35 ignition heater, 36 fuel cell stack, 37 combustion catalyst, 40 raw fuel gas supply device, 41 raw fuel gas supply pipe, 42, 43 raw fuel gas supply valve, 44 orifice , 45 Raw fuel gas pump, 46 desulfurizer, 47 pressure sensor, 48 flow sensor, 50 air supply device, 51 air supply pipe, 52 filter, 53 air blower, 54 flow sensor, 55 reformed water supply device, 56 reformed water supply Pipe, 57 reformed water tank, 58 reformed water pump, 60 exhaust heat recovery device, 61 circulation pipe, 62 heat exchanger, 63 circulation pump, 66 condensed water supply pipe, 67 exhaust gas discharge pipe, 71 power conditioner, 72 power supply board, 80 control device, 81 CPU, 82 ROM, 83 RAM, 84 flash memory, 85 timer, 90 display panel, 91-93 temperature sensor, 95 flammable gas sensor, 100 hot water supply unit, 101 hot water storage tank.

Claims (4)

A fuel cell system including a fuel cell that generates electricity based on a reformed gas containing hydrogen and an oxidant gas.
A reforming unit that reforms the raw material gas into the reforming gas using steam and supplies it to the fuel cell.
A vaporization unit that vaporizes water and supplies it to the reforming unit,
A water tank to store water and
A water pipe connected to the vaporization unit and the water tank,
A fixed-quantity water pump installed in the water pipe that can feed liquid in both forward and reverse directions,
A combustion part that heats the reforming part and the vaporizing part by the heat of combustion,
When the system is started, the water is supplied to the vaporization unit after performing water level adjustment control for driving the water pump for a certain period of time so that the water level in the water pipe becomes a predetermined water level from the state where the water in the water pipe is empty. A control device that controls the water pump and
A temperature sensor that detects the temperature of the vaporized part or the modified part, and
Equipped with a,
After performing the water level adjustment control, the control device waits in a state where the drive of the water pump is stopped, and the water is at a timing when a predetermined standby time elapses after the ignition of the combustion unit is started. The operation of the pump is started to start the water supply to the vaporization unit, and the standby time is changed based on the temperature detected by the temperature sensor after the water supply to the vaporization unit is started.
Fuel cell system. The fuel cell system according to claim 1.
The control device maintains the standby time when the detected temperature is in the appropriate range, and changes the standby time so that the detected temperature becomes shorter when the detected temperature is higher than the appropriate range, and the detected temperature. The waiting time is changed so that when is lower than the appropriate range, it becomes longer.
Fuel cell system. The fuel cell system according to claim 2.
The control device shuts down the system when the detected temperature is in the abnormal range.
Fuel cell system. The fuel cell system according to any one of claims 1 to 3.
After the system is stopped, the control device controls the water pump so that the water in the water pipe is emptied by liquid feeding in the reverse direction.
Fuel cell system.

Images