JP2020184454A - Fuel cell system - Google Patents

Abstract

To appropriately prevent reformed gas flowing through a reflux flow passage from leaking to the outside with a simple configuration.SOLUTION: A fuel cell system comprises: a desulfurizer for desulfurizing a sulfur content contained in raw fuel gas; a reformer for reforming the desulfurized raw fuel gas using reforming water to generate reformed gas; a combustion unit for burning reformed gas having passed through a fuel cell; a condensation unit for condensing combustion exhaust gas generated via combustion of reformed gas; a first condensate water flow passage for supplying condensate water condensed from combustion exhaust gas to a reformed water tank; an exhaust flow passage for discharging remaining combustion exhaust gas to the outside from an exhaust port; a reflux flow passage for making part of reformed gas generated by the reformer reflow to the desulfurizer; and a second condensate water flow passage that is connected so that condensate water condensed from reformed gas in the reflux flow passage can be supplied, is connected to the condensation unit, and has staying water by which a water seal part is formed. The exhaust flow passage further functions as a water supply passage capable of supplying water injected from the exhaust port to the first condensate water flow passage and the second condensate water flow passage.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fuel cell system.

Conventionally, as this type of fuel cell system, a desulfurizer that removes the sulfur component in the fuel gas, a reformer that reforms the desulfurized fuel gas into a reformed gas containing hydrogen, a reformed gas and oxidation Those equipped with a fuel cell that generates electricity by using an agent gas have been proposed. For example, in the fuel cell system of Patent Document 1, a recycling flow path (circulation flow path) for returning a part of the reformed gas reformed by the reformer to the desulfurization device and condensed water condensed in the recycling flow path are used. It is provided with a drainage channel for drainage, and drainage from the drainage channel is performed from both the U-shaped pipe that seals the drainage channel and the tank connected to the U-shaped pipe.

Further, the fuel cell system of Patent Document 2 stores a combustor that heats the reformer, an exhaust flow path through which the exhaust gas discharged from the combustor flows, and condensed water condensed in the exhaust flow path, and also exhaust gas. It is equipped with a water storage device having a water sealing structure that prevents the exhaust gas from flowing into the drainage channel, a water level detector that detects the water level of the water storage device, and a switch that opens and closes the drainage path. When the water level detector detects that the water level of the water storage device is below a predetermined height, the fuel cell system closes the switch to maintain the water seal.

JP-A-2018-35061 Japanese Unexamined Patent Publication No. 2013-206774

By the way, in the fuel cell system of Patent Document 1 described above, there is no mention of how to supply water to a U-shaped pipe or the like in an initial state such as when the system is installed. It is conceivable to provide a dedicated supply path for supplying water to the U-shaped pipe or the like, or to configure the system so that water can be supplied to the U-shaped pipe or the like from another flow path, but the system configuration becomes complicated. .. Not only that, since condensed water is supplied during operation, it is necessary only in the initial state and is rarely used thereafter, resulting in an unnecessary configuration. Further, a configuration including a switch for keeping the water seal, such as the fuel cell system of Patent Document 2, complicates the system configuration and causes an increase in cost.

An object of the present invention is to appropriately prevent the reformed gas flowing through the reflux channel from leaking to the outside with a simple configuration.

The present invention has taken the following measures 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 reforming gas containing hydrogen and an oxidant gas containing oxygen.
A raw fuel gas supply device that supplies raw material gas and
A desulfurizer that desulfurizes the sulfur content contained in the raw material fuel gas,
A reformer that produces the reformed gas by reforming the raw fuel gas desulfurized by the desulfurizer with reformed water.
The reformed water tank that stores the reformed water and
A combustion unit that burns the reformed gas that has passed through the fuel cell,
A condensing part that condenses the combustion exhaust gas generated by the combustion of the reformed gas, and
A first condensed water flow path connected to the condensing portion and supplying condensed water condensed from the combustion exhaust gas to the reforming water tank.
An exhaust flow path that is connected to the condensing portion and discharges the remaining combustion exhaust gas from which the condensed water is generated to the outside through an exhaust port.
A reflux channel for refluxing a part of the reformed gas generated by the reformer to the desulfurizer.
A second condensed water stream that is connected to the reflux channel so that condensed water condensed from the reformed gas in the reflux channel can be supplied and is connected to the condensed portion to form a water seal with the retained water. Road and
With
The gist of the exhaust flow path is that it also functions as a water supply channel capable of supplying water injected from the exhaust port to the first condensed water flow path and the second condensed water flow path via the condensing portion. ..

In the fuel cell system of the present invention, the condensing portion that condenses the combustion exhaust gas generated by the combustion of the reforming gas has a first condensed water flow path that supplies the condensed water condensed from the combustion exhaust gas to the reforming water tank. , The exhaust flow path that discharges the remaining combustion exhaust gas for which condensed water is generated to the outside from the exhaust port, and the condensed water condensed from the reformed gas in the recirculation flow path are connected to the recirculation flow path so that they can be supplied. At the same time, it is connected to a second condensed water flow path that is connected to the condensing portion and forms a water sealing portion with the retained water. The exhaust flow path also functions as a water supply channel capable of supplying the water injected from the exhaust port to the first condensed water flow path and the second condensed water flow path via the condensing portion. As a result, it is possible to prevent the reformed gas flowing through the reflux channel from leaking to the outside at the water sealing portion of the second condensed water channel. Further, since the water for forming the water seal portion and the water for the reformed water tank can be supplied by using the exhaust flow path, it is not necessary to provide a water supply channel or the like for that purpose. Therefore, it is possible to appropriately prevent the reformed gas flowing through the reflux channel from leaking to the outside with a simple configuration.

In the fuel cell system of the present invention, in the condensed portion, the connecting portion connected to the exhaust flow path is connected to the first condensed water flow path and the second condensed water flow path. It may be provided so that the height position is higher than that of the above. In this way, even if the exhaust flow path is configured to function as a water supply channel, it is possible to prevent the exhaust flow path from being blocked by condensed water during system operation.

In the fuel cell system of the present invention, the condensing portion is provided so that the connecting portion connected to the second condensed water flow path is at a lower height position than the connecting portion connected to the first condensed water flow path. It may be the one that has been. In this way, water can be supplied to the second condensed water flow path before the first condensed water flow path to form the water sealing portion. Further, since not only the condensed water in the reflux channel but also the condensed water condensed in the condensing portion can be preferentially supplied to the second condensed water channel, it is possible to prevent the second condensed water channel from becoming short of water. It can be more reliably sealed with water.

The fuel cell system of the present invention includes a water level sensor that detects the water level of the reformed water tank, and determines the retention of water in the second condensed water flow path by the water level sensor at a predetermined water level of the reformed water tank. It may be performed based on the detection of. In this way, it is possible to know that the water supply to the second condensed water flow path is completed without providing the water level sensor in the second condensed water flow path. Therefore, the cost can be reduced and the configuration can be simplified as compared with the case where the water level sensor is provided in each of the second condensed water flow path and the reforming water tank.

It is a block diagram which shows the outline of the structure of the fuel cell system 10. It is an enlarged view of the part A of FIG. It is explanatory drawing which shows the state of the water supply work to the drainage pipe 38 and the reforming water tank 53. It is explanatory drawing which shows the state in operation of the fuel cell system 10.

Next, 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, and FIG. 2 is an enlarged view of part A in FIG. As shown in FIG. 1, the fuel cell system 10 includes a power generation unit 20 that generates power, a hot water storage tank 80 that stores hot water heated by heat from the power generation unit 20, a control device 90 that controls the entire system, and the like. .. These are housed in the housing 12. The fuel cell system 10 can supply the electric power generated by the power generation unit 20 to home appliances and the like of a house (not shown), and can supply the hot water stored in the hot water storage tank 80 to a bathroom shower, a washroom, and the like. ..

As shown in FIG. 1, the power generation unit 20 includes a power generation module 30, a raw fuel gas supply device 40, an air supply device 45, a reformed water supply device 50, and an exhaust heat recovery device 70.

The power generation module 30 includes a vaporizer 32 that vaporizes reformed water to generate steam, a reformer 33 that reforms raw fuel gas such as natural gas and LP gas by steam reforming, and reformed gas and oxidation. It has a fuel cell stack 35 and the like that generate power by being supplied with an agent gas. The vaporizer 32, the reformer 33, and the fuel cell stack 35 are housed in a box-shaped module case 31 formed of a heat insulating material. In the module case 31, the fuel that has passed through the fuel cell stack 35 in order to start the fuel cell stack 35, generate steam in the vaporizer 32, and supply heat required for the steam reforming reaction in the reformer 33. A combustion unit 36 for burning off gas (anode off gas) and oxidizing agent off gas (cathode off gas) is provided.

The fuel cell stack 35 includes a solid oxide fuel cell cell including 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 a laminated product. The fuel cell stack 35 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.

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 a gas supply valve 42, a gas pump 43, a desulfurizer 44, a flow rate sensor (not shown), and the like in order from the gas supply source 1 side. Further, an orifice 41a is provided between the gas supply valve 42 of the raw material fuel gas supply pipe 41 and the gas pump 43. The raw material fuel gas supply device 40 drives the gas pump 43 with the gas supply valve 42 opened to desulfurize the raw material fuel gas from the gas supply source 1 and supply it to the vaporizer 32.

A part of the reformed gas is returned to the desulfurization device 44 to supply hydrogen necessary for desulfurization to the reformed gas supply pipe 34 that supplies the reformed gas generated by the reformer 33 to the fuel cell stack 35. A return pipe 37 for the purpose is connected. One end of the recirculation pipe 37 is connected to the reforming gas supply pipe 34, and the other end is connected to the upstream side (between the orifice 41a and the gas pump 43) of the gas pump 43 in the raw fuel gas supply pipe 41. The reflux pipe 37 is provided with an orifice 37a for adjusting the flow rate of the reformed gas to be refluxed from the reformed gas supply pipe 34 to the desulfurizer 44.

Further, the reflux pipe 37 is connected to a drain pipe 38 for discharging the condensed water in which the reforming gas flowing through the reflux pipe 37 is cooled and condensed. One end of the drain pipe 38 is connected to the upstream side of the orifice 37a in the reflux pipe 37, and the other end is connected to the heat exchanger 73 described later of the exhaust heat recovery device 70. The drain pipe 38 has a bent shape so that water can stay, and the retained water is prevented so that the gas component (hydrogen) in the reforming gas flowing through the return pipe 37 is not discharged to the outside through the drain pipe 38. A water-sealing portion (water-sealing structure) for water-sealing the drain pipe 38 is formed.

The air supply device 45 has an air supply pipe 46 that connects the filter 47 that communicates with the outside air and the fuel cell stack 35. An air blower 48 is provided in the air supply pipe 46, and by driving the air blower 48, air sucked through the filter 47 is supplied to the fuel cell stack 35. The air supply pipe 46 is provided with a flow rate sensor or the like (not shown).

The reformed water supply device 50 has a reformed water supply pipe 51 that connects the reformed water tank 53 for storing the reformed water and the vaporizer 32. The reforming water tank 53 is provided with a reforming water pump 52, and by driving the reforming water pump 52, the reforming water in the reforming water tank 53 is pumped up and passed through the reforming water supply pipe 51. Is supplied to the vaporizer 32. Further, the reforming water tank 53 includes a float sensor 54 that detects the water level of the reforming water tank 53 by a float that is displaced up and down following the water level of the reforming water in the tank, and the reforming water in the tank. A drain port 55 is provided at a height position at which water can be discharged when the water level is near the full water level. The reformed water supply pipe 51 is provided with a flow rate sensor or the like (not shown).

The exhaust heat recovery device 70 exchanges heat between the circulation pipe 71 that circulates the hot water in the hot water storage tank 80 by driving the circulation pump 72, and the hot water in the circulation pipe 71 and the combustion exhaust gas from the combustion unit 36. It has a vessel 73. The water vapor component of the combustion exhaust gas from the combustion unit 36 is condensed by heat exchange, and the condensed water (condensed water) can be recovered in the reformed water tank 53 via the condensed water supply pipe 74. A water purifier 75 is provided in the condensed water supply pipe 74, and the water purified (purified) by the water purifier 75 is collected in the reformed water tank 53. Further, the remaining exhaust gas (gas component) passes through the exhaust gas discharge pipe 76 and is discharged to the outside from the exhaust port 76a formed in the upper part of the housing 12.

In addition to connecting the condensed water supply pipe 74 and the exhaust gas discharge pipe 76 to the heat exchanger 73, a drain pipe 38 for discharging the condensed water of the reflux pipe 37 is also connected. As shown in FIG. 2, the lower part of the heat exchanger 73 is a connection portion 73a to which the exhaust gas discharge pipe 76 is connected and a connection portion (first condensed water connection portion) 73b to which the condensed water supply pipe 74 is connected. And a connection portion (second condensed water connection portion) 73c to which the drain pipe 38 is connected are provided. Since the connecting portions 73a to 73c are provided so as to communicate with each other in the heat exchanger 73, the drain pipe 38, the condensed water supply pipe 74, and the exhaust gas discharge pipe 76 communicate with each other in the heat exchanger 73. It will be. Further, the height positions of the connecting portions 73a to 73c from a predetermined reference position are different from each other. The height position Ha of the connection portion 73a of the exhaust gas discharge pipe 76 is provided at a position higher than the height position Hb of the connection portion 73b of the condensed water supply pipe 74 and the height position Hc of the connection portion 73c of the drain pipe 38. ing. Further, the height position Hc of the connecting portion 73c of the drainage pipe 38 is provided at a position lower than the height position Hb of the connecting portion 73b of the condensed water supply pipe 74. That is, in the present embodiment, the connection portion 73a of the exhaust gas discharge pipe 76, the connection portion 73b of the condensed water supply pipe 74, and the connection portion 73c of the drain pipe 38 are provided in order from the highest height position. There is.

Although not shown, the control device 90 is a microcomputer centered on a CPU, and includes a ROM, a RAM, a timer, an input / output port, and a communication port in addition to the CPU. Various detection signals from each flow rate sensor and float sensor 54 are input to the control device 90 via the input port. Further, the control device 90 outputs a drive signal, a control signal, and the like to each unit via the output port.

Here, in the fuel cell system 10, when the drain pipe 38 and the reforming water tank 53 are empty, such as when newly installed, water supply work (water filling) is required to start the system. FIG. 3 is an explanatory diagram showing a state of water supply work to the drain pipe 38 and the reforming water tank 53. In the water supply work, the operator removes the cap attached to the exhaust port 76a and pours the water in the water supply bottle WB from the spout WBa to the exhaust port 76a (FIG. 3 (1)) from the exhaust port 76a. Water is injected into the exhaust gas discharge pipe 76. The water supply bottle WB is fixed to the housing 22 when the spout WBa is fitted into the exhaust port 76a, and the operator can perform the water supply work simply by setting the water supply bottle WB in the exhaust port 76a. Can be done.

When the water injected into the exhaust gas discharge pipe 76 reaches the heat exchanger 73 via the connection portion 73a, it flows into the condensed water supply pipe 74 via the connection portion 73b and the drain pipe via the connection portion 73c. It flows into 38. As described above, the height position Hc of the connecting portion 73c of the drainage pipe 38 is provided at a position lower than the height position Hb of the connecting portion 73b of the condensed water supply pipe 74. Therefore, water is more likely to flow into the drain pipe 38 from the heat exchanger 73 than the condensed water supply pipe 74, and the water injected into the exhaust gas discharge pipe 76 and reaches the heat exchanger 73 is first connected to the connection portion 73c. The water flows into the drain pipe 38 (FIG. 3 (2)), and the inflowing water stays there to form a water seal portion WS. Then, when the water sealing portion WS is formed in the drain pipe 38 and the water further stays at the height position Hb of the connecting portion 73b, the water flows from the connecting portion 73b into the condensed water supply pipe 74 (FIG. 3 (3)). .. Since the condensed water supply pipe 74 is provided with the water purifier 75, the inflowing water is purified by the water purifier 75 and then supplied to the reformed water tank 53 (FIG. 3 (4)). It stays in the reformed water tank 53. The control device 90 can detect that the water has sufficiently accumulated in the reforming water tank 53 and has reached a predetermined water level or higher by the detection signal (on signal) of the float sensor 54. Further, when it is detected that the reformed water tank 53 is above the predetermined water level, it can be determined that water has already accumulated in the drain pipe 38 and the water sealing portion WS is formed. Therefore, the water supply operation may be performed until the float sensor 54 of the reforming water tank 53 detects that the water level is equal to or higher than the predetermined water level. By such a water supply operation, the necessary water can be supplied in the order of the drain pipe 38 (water sealing portion WS) and the reformed water tank 53.

When the system start condition is satisfied, one of the conditions is that the water level of the reforming water tank 53 is equal to or higher than the predetermined water level, the fuel cell system 10 performs the system start process. Run. In the system start-up process, for example, the corresponding auxiliary machinery is sequentially controlled, the fuel component is adsorbed on the desulfurizer 44 to suppress the air-fuel ratio deviation of the mixed gas, the fuel adsorption process, the purge process of the combustion unit 36, and the combustion unit 36 It is carried out by sequentially executing the off-gas ignition treatment and the steam reforming treatment in. When the system startup is completed, the fuel cell system 10 starts operation.

The fuel cell system 10 executes raw material fuel gas supply control, air supply control, and reformed water supply control in the power generation process during operation. In the raw fuel gas supply control, a target gas flow rate is set based on the system required output, and the gas pump 43 is controlled so that the raw fuel gas is supplied according to the set target gas flow rate. In the air supply control, the target air flow rate is set so as to have a predetermined air-fuel ratio with respect to the target gas flow rate, and the air blower 48 is controlled so that air is supplied by the set target air flow rate. In the reformed water supply control, a target water amount is set based on the system required output, and the reformed water pump 52 is controlled so that the reformed water is supplied according to the set target water amount. FIG. 4 is an explanatory diagram showing a state in which the fuel cell system 10 is in operation. During the operation of the fuel cell system 10, the condensed water of the return pipe 37 flows into the drain pipe 38. Further, since water is more likely to flow into the drain pipe 38 from the heat exchanger 73 than the condensed water supply pipe 74, the condensed water of the heat exchanger 73 also flows into the drain pipe 38. Therefore, since the amount of water (full state) of the water sealing portion WS of the drain pipe 38 can be appropriately maintained, it is possible to prevent the reformed gas of the reflux pipe 37 from leaking to the outside. The height of the drain pipe 38 is set in the drain pipe 38 due to the head difference between the connection side of the return pipe 37 and the connection side of the heat exchanger 73 even if the maximum pressure of the return pipe 37 acts during operation. The height is set so that water does not escape. Further, when it is detected from the detection signal from the float sensor 54 that the water level of the reforming water tank 53 is sufficiently high, the water sealing portion WS of the drain pipe 38 is also in a full water state and is securely sealed. You can know that you are there. That is, the water level of the water sealing portion WS during operation can also be monitored by the detection signal from the float sensor 54.

Further, when the fuel cell system 10 detects a drop in the water level of the reforming water tank 53 during operation by the detection signal from the float sensor 54, the fuel cell system 10 performs output limit control for lowering the system required output. As a result, the amount of condensed water generated by the heat exchanger 73 can be increased, and the water level in the reforming water tank 53 can be restored. Since water is more likely to flow into the drain pipe 38 from the heat exchanger 73 than the condensed water supply pipe 74, and the amount of water in the water sealing portion WS of the drain pipe 38 can be appropriately maintained, the reformed water tank 53 Even if a drop in the water level is detected, water still remains in the water sealing portion WS and the water sealing property is not impaired. Further, if the amount of condensed water generated by the heat exchanger 73 is increased, the water is preferentially supplied from the drain pipe 38. Therefore, even if the water in the drain pipe 38 is reduced, the water level is quickly restored and the water sealability is improved. Can be secured.

Further, when the water stays in the drain pipe 38 to the extent that the condensed water overflows from the drain pipe 38, the overflowed water flows into the reformed water tank 53 from the condensed water supply pipe 74, and the reformed water tank 53 is near the full water level. When it becomes, it is discharged from the drain port 55. The connection portion 73a of the exhaust gas discharge pipe 76 is provided at a position higher than the connection portion 73b of the condensed water supply pipe 74 and the connection portion 73c of the drain pipe 38. From these facts, since the water level in the heat exchanger 73 does not rise beyond the height position Ha, it is possible to prevent the connecting portion 73a from being blocked by water (condensed water). That is, when the exhaust gas discharge pipe 76 is configured to function as a water supply channel, it is possible to prevent the exhaust from the exhaust gas discharge pipe 76 from being obstructed.

In the fuel cell system 10 described above, the exhaust gas discharge pipe 76 also serves as a water supply channel capable of supplying the water injected from the exhaust port 76a to the condensed water supply pipe 74 and the drain pipe 38 via the heat exchanger 73. Function. Therefore, the exhaust gas discharge pipe 76 may be used for supplying water to the water seal portion WS and the reformed water tank 53, and it is not necessary to provide a dedicated water supply channel, so that a simpler configuration can be achieved. ..

Further, the heat exchanger 73 is provided so that the connection portion 73a of the exhaust gas discharge pipe 76 is higher in height than the connection portion 73b of the condensed water supply pipe 74 and the connection portion 73c of the drain pipe 38. Therefore, it is possible to prevent the exhaust gas discharge pipe 76 from being blocked by the condensed water.

Further, in the heat exchanger 73, since the connecting portion 73c of the drain pipe 38 is lower in height position than the connecting portion 73b of the condensed water supply pipe 74, water is first supplied to the drain pipe 38 to form the water sealing portion WS. Can be formed appropriately. Further, since the condensed water from the heat exchanger 73 can be preferentially supplied to the drain pipe 38 during the operation, the amount of water in the water sealing portion WS can be appropriately maintained.

Further, the reforming water tank 53 is provided with the float sensor 54, and the determination of the retention of water in the drain pipe 38 is performed based on the detection of the predetermined water level of the reforming water tank 53 by the float sensor 54. Therefore, it can be confirmed that the water supply to the drain pipe 38 is completed and that the water sealing portion WS is formed with a simple configuration that suppresses the cost.

In the above-described embodiment, the connection portion 73a of the exhaust gas discharge pipe 76 is provided so as to be higher in height than the connection portion 73b of the condensed water supply pipe 74 and the connection portion 73c of the drain pipe 38. , Not limited to this. For example, the connecting portion 73a may be provided at a height position equivalent to that of the connecting portion 73b or the connecting portion 73c.

In the embodiment, the connecting portion 73c of the drainage pipe 38 is provided so as to be lower in height than the connecting portion 73b of the condensed water supply pipe 74, but the present invention is not limited to this. For example, the connecting portion 73c may be provided so that the height position is higher than that of the connecting portion 73b, or the connecting portions 73b and 73c may be provided so as to be at the same height position.

In the embodiment, the float sensor 54 included in the reforming water tank 53 detects that water is retained in the drain pipe 38 (full state), but the present invention is not limited to this, and the water level sensor is not limited to this. Etc. may be provided to directly detect the water level of the drain pipe 38.

In the embodiment, the water supply work is performed using the water supply bottle WB, but the present invention is not limited to this, and the water supply work may be performed using a water supply hose or the like. Further, the exhaust port 76a does not necessarily have to be provided on the upper surface of the housing 22, and may be provided on the side surface of the housing 22.

The correspondence between the main elements of the present embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the present embodiment, the fuel cell stack 35 corresponds to the "fuel cell", the raw fuel gas supply device 40 corresponds to the "raw fuel gas supply device", and the desulfurizer 44 corresponds to the "desulfurizer". The vessel 33 corresponds to the "reformer", the reformer water tank 53 corresponds to the "reformer water tank", the combustion unit 36 corresponds to the "combustion unit", and the heat exchanger 73 corresponds to the "condensation unit". Correspondingly, the condensed water supply pipe 74 corresponds to the "first condensed water flow path", the exhaust gas discharge pipe 76 corresponds to the "exhaust flow path", the recirculation pipe 37 corresponds to the "recirculation flow path", and the drainage pipe. 38 corresponds to the "second condensed water flow path". Further, the connecting portion 73a corresponds to the "connecting portion connected to the exhaust flow path", the connecting portion 73b corresponds to the "connecting portion connected to the first condensed water flow path", and the connecting portion 73c corresponds to the "second condensed water flow path". It corresponds to "a connection part connected to a water flow path". Further, the float sensor 54 corresponds to the "water level sensor".

The correspondence between the main elements of the present embodiment and the main elements of the invention described in the column of means for solving the problem is the invention described in the column of the means for solving the problem in the present embodiment. Since it is an example for concretely explaining a mode for carrying out the above, 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 present embodiment is the invention described in the column of means for solving the problem. It is just a concrete example of.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course.

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

1 Gas supply source, 10 fuel cell system, 12 housings, 20 power generation units, 30 power generation modules, 31 module cases, 32 vaporizers, 33 reformers, 34 reformed gas supply pipes, 35 fuel cell stacks, 36 combustion parts , 37 return pipe, 37a orifice, 38 drain pipe, 40 raw fuel gas supply device, 41 raw fuel gas supply pipe, 41a orifice, 42 gas supply valve, 43 gas pump, 44 desulfurizer, 45 air supply device, 46 air supply pipe , 47 filter, 48 air blower, 50 reformed water supply device, 51 reformed water supply pipe, 52 reformed water pump, 53 reformed water tank, 54 float sensor, 55 drain port, 70 exhaust heat recovery device, 71 circulation piping , 72 Circulation pump, 73 Heat exchanger, 73a, 73b, 73c connection, 74 Condensed water supply pipe, 75 Water purifier, 76 Exhaust gas discharge pipe, 76a Exhaust port, 80 Hot water storage tank, 90 Control device, WB water supply bottle , WBa water supply port, WS water seal.

Claims (4)

A fuel cell system including a fuel cell that generates electricity based on a reforming gas containing hydrogen and an oxidant gas containing oxygen.
A raw fuel gas supply device that supplies raw material gas and
A desulfurizer that desulfurizes the sulfur content contained in the raw material fuel gas,
A reformer that produces the reformed gas by reforming the raw fuel gas desulfurized by the desulfurizer with reformed water.
The reformed water tank that stores the reformed water and
A combustion unit that burns the reformed gas that has passed through the fuel cell,
A condensing part that condenses the combustion exhaust gas generated by the combustion of the reformed gas, and
A first condensed water flow path connected to the condensing portion and supplying condensed water condensed from the combustion exhaust gas to the reforming water tank.
An exhaust flow path that is connected to the condensing portion and discharges the remaining combustion exhaust gas from which the condensed water is generated to the outside through an exhaust port.
A reflux channel for refluxing a part of the reformed gas generated by the reformer to the desulfurizer.
A second condensed water stream that is connected to the reflux channel so that condensed water condensed from the reformed gas in the reflux channel can be supplied and is connected to the condensed portion to form a water seal with the retained water. Road and
With
The exhaust flow path is a fuel cell system that also functions as a water supply channel capable of supplying water injected from the exhaust port to the first condensed water flow path and the second condensed water flow path via the condensing portion. The fuel cell system according to claim 1.
The height position of the condensing portion is higher than that of the connecting portion connected to the exhaust flow path and the connecting portion connected to the first condensed water flow path and the connecting portion connected to the second condensed water flow path. Fuel cell system provided in the same way. The fuel cell system according to claim 1 or 2.
The condensing portion is a fuel cell system in which a connecting portion connected to the second condensed water flow path is provided so that the height position is lower than the connecting portion connected to the first condensed water flow path. The fuel cell system according to claim 3.
A water level sensor for detecting the water level of the reformed water tank is provided.
A fuel cell system that determines the retention of water in the second condensed water flow path based on the detection of a predetermined water level in the reforming water tank by the water level sensor.