JP2023122419A - Ammonia removal system - Google Patents

Abstract

To provide a technique capable of using an eliminator to the maximum ability thereof and also capable of reducing the replacement frequency of the eliminator.SOLUTION: An ammonia removal system includes: a sensor detecting the state of reformed gas flowing through a first reformed gas passage; a first valve provided in the first reformed gas passage; a first eliminator generating fuel gas by removing ammonia from reformed gas passing through the first reformed gas passage; and a control unit. The first valve is configured to be switchable between a first state where reformed gas is supplied to the first eliminator through the first reformed gas passage and a second state where reformed gas is not supplied to the first eliminator through the first reformed gas passage. The control unit switches the first valve from the first state to the second state when it is determined, based on the detection value of the sensor, that the amount of ammonia supplied to the first eliminator through the first reformed gas passage reaches a predetermined first reference amount.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The technology disclosed herein relates to ammonia removal systems.

Patent Literature 1 discloses an ammonia removal facility. The ammonia removal equipment of Patent Document 1 includes a reformed gas passage through which reformed gas flows, an on-off valve provided in the reformed gas passage, and a remover that removes ammonia from the reformed gas that has passed through the reformed gas passage. It has Further, the ammonia removal equipment of Patent Document 1 is equipped with an ammonia concentration measuring device that measures the concentration of ammonia in the treated gas after being treated by the remover, and the ammonia concentration measured by the ammonia concentration measuring device exceeds the threshold value. The on-off valve is closed when

Japanese Patent No. 6810910

In the ammonia removal equipment, it is difficult to predict when the remover will break through, and the remover may not be used to the limit of its capacity, resulting in frequent replacement of the remover. In the ammonia removal equipment of Patent Document 1, the concentration of ammonia in the treated gas after being treated by the remover is measured. After the breakthrough, the on-off valve is closed. To prevent this, it is necessary to replace the remover at an early stage, and as a result, the remover needs to be replaced more frequently. Therefore, the present specification provides a technique that allows the remover to be used to the limit of its ability and reduces the frequency of replacement of the remover.

The ammonia removal system disclosed in the present specification includes a reformer that reforms a raw material gas to produce a reformed gas, and a first reformed gas passage through which the reformed gas produced by the reformer flows. a sensor for detecting the state of the reformed gas flowing through the first reformed gas passage; a first valve provided in the first reformed gas passage; and a reformed gas passing through the first reformed gas passage. a first remover that removes ammonia from the fuel gas to generate fuel gas; and a controller. The first valve has a first state in which reformed gas is supplied to the first remover through the first reformed gas passage, and a first state in which reformed gas is supplied to the first remover through the first reformed gas passage. It is configured to be switchable between a second state in which it is not supplied. When the controller determines that the amount of ammonia supplied to the first remover through the first reformed gas passage has reached a predetermined first reference amount based on the detected value of the sensor, Switching the first valve from the first state to the second state.

According to this configuration, by switching the first valve from the first state to the second state when it is determined that the amount of ammonia supplied to the first remover has reached the first reference amount, the first remover The reformed gas can be supplied to the first remover until just before the breakthrough. As a result, the first remover can be used to the limit of its ability, and as a result, the replacement frequency of the first remover can be reduced.

The sensor includes a temperature sensor that detects the temperature of the reformed gas flowing through the first reformed gas passage, and a pressure sensor that detects the pressure of the reformed gas flowing through the first reformed gas passage. good too. When the integrated value obtained by time-integrating the ammonia concentration estimated from the detected value of the temperature sensor and the detected value of the pressure sensor reaches a predetermined first integration reference value, the control unit performs the first revision. It may be determined that the amount of ammonia supplied to the first remover through the quality gas passage has reached the first reference amount.

According to this configuration, the amount of ammonia supplied to the first remover can be accurately estimated by using the temperature sensor and the pressure sensor. This makes it possible to accurately control the timing of switching the first valve from the first state to the second state.

The ammonia removal system is branched from the first reformed gas passage via the first valve, and includes a second reformed gas passage through which the reformed gas produced by the reformer flows, and the second reformer. A second remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the reformed gas passage may be further provided. The first valve is configured such that the reformed gas is supplied to the first remover through the first reformed gas passage and the reformed gas is not supplied to the second remover through the second reformed gas passage. the first state and the second state in which reformed gas is not supplied to the first remover through the first reformed gas passage and reformed gas is supplied to the second remover through the second reformed gas passage. It may be configured to be switchable between two states.

According to this configuration, the second remover can be used in place of the first remover at the timing when the first remover has been used to the limit of its ability. This allows continuous and efficient use of the ammonia removal system.

The ammonia removal system branches from the first reformed gas passage upstream of the first valve, and includes a second reformed gas passage through which the reformed gas produced by the reformer flows; 2 further comprising: a second valve provided in the reformed gas passage; and a second remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the second reformed gas passage. good too. The second valve has a first state in which reformed gas is supplied to the second remover through the second reformed gas passage, and a first state in which reformed gas is supplied to the second remover through the second reformed gas passage. It may be configured to be switchable between a second state in which it is not supplied. The controller determines that the amount of ammonia supplied to the first remover through the first reformed gas passage has reached a predetermined third reference amount that is less than the first reference amount based on the detection value of the sensor. When determining that the second valve is switched from the second state to the first state, the degree of opening of the second valve may be controlled to be less than the degree of opening of the first valve.

According to this configuration, it is possible to provide a period during which the first remover and the second remover are used in parallel. As a result, when switching from the first remover to the second remover, the flow of the reformed gas can be smoothly switched without interruption.

After controlling the degree of opening of the second valve to be less than the degree of opening of the first valve, the controller controls the opening degree of the second valve to the first remover through the first reformed gas passage based on the detection value of the sensor. The degree of opening of the second valve may be increased when it is determined that the amount of supplied ammonia has reached the predetermined first reference amount.

According to this configuration, it is possible to smoothly switch to the second remover at the timing when the first remover is used to the limit of its ability.

The ammonia removal system disclosed in the present specification includes a reformer that reforms a raw material gas to produce a reformed gas, and a first reformed gas passage through which the reformed gas produced by the reformer flows. a sensor for detecting the state of the reformed gas flowing through the first reformed gas passage; a first pump provided in the first reformed gas passage; and the reformed gas passing through the first reformed gas passage. a first remover that removes ammonia from the fuel gas to generate fuel gas; and a controller. The first pump is configured to supply the reformed gas to the first remover through the first reformed gas passage by pumping the reformed gas, and to supply the reformed gas to the first remover through the first reformed gas passage. It is configured to be switchable between a stopped state in which reformed gas is not supplied to the vessel. When the controller determines that the amount of ammonia supplied to the first remover through the first reformed gas passage has reached a predetermined first reference amount based on the detected value of the sensor, Switching the first pump from the operating state to the stopped state.

According to this configuration, similarly to the above, the first remover can be used to the limit of its ability, and the replacement frequency of the first remover can be reduced.

The ammonia removal system branches off from the first reformed gas passage on the upstream side of the first pump, and includes a second reformed gas passage through which the reformed gas produced by the reformer flows; 2 further comprising: a second pump provided in the reformed gas passage; and a second remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the second reformed gas passage. good too. The second pump is configured to supply the reformed gas to the second remover through the second reformed gas passage by pumping the reformed gas, and to supply the second remover through the second reformed gas passage. It may be configured to be switchable between a stopped state in which reformed gas is not supplied to the vessel. The controller controls the amount of ammonia supplied to the first remover through the first reformed gas passage to reach a predetermined third reference amount, which is less than the predetermined first reference amount, based on the detection value of the sensor. When it is determined that the second pump has been stopped, the second pump may be switched from the stopped state to the operating state and the output of the second pump may be controlled to be less than the output of the first pump.

According to this configuration, similarly to the above, when switching from the first remover to the second remover, the flow of the reformed gas can be smoothly switched without interruption.

A fuel cell system may include the ammonia removal system described above and a fuel cell that generates power using the fuel gas generated by the first remover.

According to this configuration, while the first remover is used to the limit of its capacity, it is possible to prevent ammonia contained in the reformed gas from being supplied to the fuel cell due to breakthrough of the first remover. The ammonia removal system described above is particularly effective in a configuration including a fuel cell.

1 is a diagram schematically showing a fuel cell system of a first embodiment; FIG. A table showing an example of ammonia concentration related information. 4 is a flowchart of three-way valve control processing of the first embodiment; The figure which shows an example of the time integral of ammonia concentration. The figure which shows typically the fuel cell system of 2nd Example. 9 is a flowchart of on-off valve control processing of the second embodiment; The figure which shows an example of opening degree control of an on-off valve. The figure which shows typically the fuel cell system of 3rd Example. FIG. 11 is a flowchart of pump control processing of the third embodiment; FIG. The figure which shows an example of output control of a pump. The figure which shows typically the fuel cell system of 4th Example.

(First embodiment)
A fuel cell system 2 equipped with the ammonia removal system of the first embodiment will be described with reference to the drawings. As shown in FIG. 1, the fuel cell system 2 includes a raw material tank 10, a vaporizer 12, a reformer 14, a first remover 16, a second remover 18, a fuel cell 20, and a controller. 50.

The raw material tank 10 stores liquid ammonia as a raw material. A liquid passage 32 through which liquid ammonia flows is connected to the raw material tank 10 . The liquid passage 32 has an upstream end connected to the raw material tank 10 and a downstream end connected to the vaporizer 12 . Liquid ammonia is supplied from the raw material tank 10 to the vaporizer 12 through the liquid passage 32 . The liquid passage 32 is provided with a pump 22 that pumps the liquid ammonia from the upstream side to the downstream side of the liquid passage 32 .

The vaporizer 12 heats and vaporizes the liquid ammonia supplied by the liquid passage 32 . As a result, gaseous ammonia is generated as a raw material gas. A raw material gas passage 34 through which raw material gas (gaseous ammonia) flows is connected to the vaporizer 12 . The source gas passage 34 has an upstream end connected to the vaporizer 12 and a downstream end connected to the reformer 14 . The raw material gas is supplied from the vaporizer 12 to the reformer 14 through the raw material gas passage 34 .

The reformer 14 reforms the raw material gas (gaseous ammonia) supplied through the raw material gas passage 34 to generate a reformed gas. Catalysts used for reforming the raw material gas are, for example, copper, nickel, ruthenium, and the like. The reformed gas contains hydrogen generated by reforming the raw material gas. In addition, the reformed gas contains ammonia, which is a by-product of reforming, and undecomposed ammonia. The reformer 14 includes a heater 15 that heats the source gas during reforming of the source gas. Heater 15 is, for example, of electric or gas configuration.

The reformer 14 is connected to a first reformed gas passage 36 through which the produced reformed gas flows. The first reformed gas passage 36 has an upstream end connected to the reformer 14 and a downstream end connected to the first remover 16 . The reformed gas is supplied from the reformer 14 to the first remover 16 through the first reformed gas passage 36 .

A temperature sensor 28 , a pressure sensor 30 , a heat exchanger 31 and a first three-way valve 24 are provided in the first reformed gas passage 36 . The temperature sensor 28 is provided in the first reformed gas passage 36 upstream of the first three-way valve 24 and the heat exchanger 31 . The temperature sensor 28 detects the temperature of the reformed gas flowing through the first reformed gas passage 36 upstream of the first three-way valve 24 and the heat exchanger 31 . A temperature sensor 28 detects the temperature of the reformed gas before heat exchange by the heat exchanger 31 . Information on the temperature detected by the temperature sensor 28 is transmitted to the controller 50 at predetermined time intervals (for example, every 5 seconds).

The pressure sensor 30 is provided in the first reformed gas passage 36 upstream of the first three-way valve 24 and the heat exchanger 31 . The pressure sensor 30 detects the pressure of the reformed gas flowing through the first reformed gas passage 36 upstream of the first three-way valve 24 and the heat exchanger 31 . The pressure sensor 30 detects the pressure of the reformed gas before heat exchange by the heat exchanger 31 . Information on the pressure detected by the pressure sensor 30 is transmitted to the controller 50 at predetermined time intervals (for example, every 5 seconds).

The heat exchanger 31 is provided in the first reformed gas passage 36 upstream of the first three-way valve 24 . The heat exchanger 31 cools the reformed gas flowing through the first reformed gas passage 36 on the upstream side of the first three-way valve 24 to lower the temperature of the reformed gas. The heat exchanger 31 reduces the temperature of the reformed gas by heat exchange between the reformed gas and an external fluid. Although the structure of the heat exchanger 31 is not particularly limited, it includes, for example, fins for heat exchange.

The first three-way valve 24 is provided in the first reformed gas passage 36 downstream of the temperature sensor 28 , the pressure sensor 30 and the heat exchanger 31 . A second reformed gas passage 38 is connected to the first three-way valve 24 . The second reformed gas passage 38 has an upstream end connected to the first three-way valve 24 and a downstream end connected to the second remover 18 . The second reformed gas passage 38 branches off from the first reformed gas passage 36 via the first three-way valve 24 . The second reformed gas passage 38 is arranged in parallel with the first reformed gas passage 36 on the downstream side of the first three-way valve 24 .

The first three-way valve 24 opens and closes the first reformed gas passage 36 and the second reformed gas passage 38 . The first three-way valve 24 is configured to be switchable between a first state and a second state. When the first three-way valve 24 is in the first state, the reformed gas produced by the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the first three-way valve 24 is in the first state, the reformed gas produced in the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . On the other hand, when the first three-way valve 24 is in the second state, the reformed gas produced by the reformer 14 passes through the first reformed gas passage 36 upstream of the first three-way valve 24 and the second reformed gas. It is supplied to the second remover 18 through the gas passage 38 . When the first three-way valve 24 is in the second state, the reformed gas produced in the reformer 14 is not supplied to the first remover 16 through the first reformed gas passage 36 .

The first remover 16 removes ammonia from the reformed gas by adsorbing the ammonia contained in the reformed gas supplied through the first reformed gas passage 36 with an adsorbent. As a result, fuel gas with a reduced ammonia concentration is produced. Adsorbents used for adsorption of ammonia are, for example, activated carbon, zeolite, MOF (Metal Organic Framework), and the like. For example, the inside of the container of the first remover 16 is filled with an adsorbent. The first remover 16 can be replaced with a new first remover 16 after use. Alternatively, the adsorbent inside the first remover 16 may be replaced.

A first fuel gas passage 40 through which the generated fuel gas flows is connected to the first remover 16 . The first fuel gas passage 40 has an upstream end connected to the first remover 16 and a downstream end connected to the fuel cell 20 . Fuel gas is supplied from the first remover 16 to the fuel cell 20 through the first fuel gas passage 40 . A second three-way valve 26 is provided in the first fuel gas passage 40 .

The second remover 18 is arranged in parallel with the first remover 16 . The second remover 18 removes ammonia from the reformed gas by adsorbing the ammonia contained in the reformed gas supplied through the second reformed gas passage 38 with an adsorbent. As a result, fuel gas with a reduced ammonia concentration is produced. Adsorbents used for adsorption of ammonia are, for example, activated carbon, zeolite, MOF (Metal Organic Framework), and the like. For example, the interior of the container of the second remover 18 is filled with an adsorbent. The secondary remover 18 can be replaced with a new secondary remover 18 after use. Alternatively, the adsorbent inside the second remover 18 may be replaced.

A second fuel gas passage 42 through which the generated fuel gas flows is connected to the second remover 18 . The second fuel gas passage 42 has an upstream end connected to the second remover 18 and a downstream end connected to the second three-way valve 26 . The second fuel gas passage 42 joins the first fuel gas passage 40 via the second three-way valve 26 . The second fuel gas passage 42 is arranged in parallel with the first fuel gas passage 40 upstream of the second three-way valve 26 .

The second three-way valve 26 opens and closes the first fuel gas passage 40 and the second fuel gas passage 42 . The second three-way valve 26 is configured to be switchable between a first state and a second state. When the second three-way valve 26 is in the first state, the fuel gas produced by the first remover 16 is supplied to the fuel cell 20 through the first fuel gas passage 40 . When the second three-way valve 26 is in the first state, the fuel gas produced by the second remover 18 is not supplied to the fuel cell 20 through the second fuel gas passage 42 . On the other hand, when the second three-way valve 26 is in the second state, the fuel gas generated by the second remover 18 passes through the second fuel gas passage 42 and the first fuel gas passage downstream of the second three-way valve 26 . 40 to the fuel cell 20 . When the second three-way valve 26 is in the second state, the fuel gas produced by the first remover 16 is not supplied to the fuel cell 20 through the first fuel gas passage 40 .

The fuel cell 20 will be explained. An air passage 44 through which air flows is connected to the fuel cell 20 in addition to the first fuel gas passage 40 . The air passage 44 has an upstream end connected to an air supply source (not shown) and a downstream end connected to the fuel cell 20 . Air is supplied from an air supply source to the fuel cell 20 through the air passage 44 . Note that the upstream end of the air passage 44 may be open to the outside air.

The fuel cell 20 generates electricity using fuel gas supplied through the first fuel gas passage 40 and air supplied through the air passage 44 . The fuel cell 20 includes, for example, a plurality of battery cells (not shown) stacked inside a container, and each battery cell generates fuel through a chemical reaction between hydrogen contained in fuel gas and oxygen contained in air Generate electricity. The battery cell is, for example, a solid oxide fuel cell (SOFC) or a polymer electrolyte fuel cell (PEFC), but is not limited to these. In the fuel cell 20 that generates power using fuel gas, unreacted fuel gas is discharged as exhaust gas during power generation.

An exhaust gas passage 46 through which exhaust gas flows is connected to the fuel cell 20 . The exhaust gas passage 46 has an upstream end connected to the fuel cell 20 and a downstream end connected to a discharge destination (not shown). Exhaust gas is discharged from the fuel cell 20 to the discharge destination through the exhaust gas passage 46 . The discharge destination may be, for example, the reformer 14, the first remover 16, the second remover 18, or the like.

The controller 50 includes, for example, a CPU (not shown) and a storage section 52 (for example, ROM and RAM), and performs various controls and operations related to the fuel cell system 2 according to programs stored in the storage section 52. Execute the process.

The storage unit 52 of the controller 50 stores ammonia concentration related information. FIG. 2 is a table showing an example of ammonia concentration related information. As shown in FIG. 2, the ammonia concentration relationship information indicates the relationship between temperature (horizontal axis) and pressure (vertical axis) and ammonia concentration (eg, 80%, 25%, . . . ). The temperature (horizontal axis (eg, 100° C., 200° C., . do. The pressure (vertical axis (eg, 0 kPa, 100 kPa, . . . )) in the ammonia concentration relationship information corresponds to the reformed gas pressure detected by the pressure sensor 30 provided in the first reformed gas passage 36 . The ammonia concentration (for example, 80%, 25%, . The ammonia concentration related information is created in advance based on experiments and analyses, for example. The ammonia concentration relation information is not limited to the table shown in FIG. 2, and may be represented by graphs or functions, for example. The controller 50 estimates the concentration of ammonia contained in the reformed gas flowing through the first reformed gas passage 36 based on the temperature detected by the temperature sensor 28, the pressure detected by the pressure sensor 30, and the ammonia concentration relation information. do. For example, when the temperature detected by the temperature sensor 28 is 100° C. and the pressure detected by the pressure sensor 30 is 0 kPa, the controller 50 adjusts the concentration of ammonia contained in the reformed gas to 80° C. based on the ammonia concentration relationship information. %.

(Three-way valve control process; Fig. 3)
Next, the three-way valve control process of the first embodiment will be explained. The three-way valve control process of the first embodiment is started, for example, when the used first remover 16 is replaced with a new unused first remover 16 . It is assumed that the first three-way valve 24 and the second three-way valve 26 are in the first state when the three-way valve control process of the first embodiment is started. When the first three-way valve 24 is in the first state, the reformed gas produced by the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the first three-way valve 24 is in the first state, the reformed gas produced in the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . Also, when the second three-way valve 26 is in the first state, the fuel gas produced by the first remover 16 is supplied to the fuel cell 20 through the first fuel gas passage 40 . When the second three-way valve 26 is in the first state, the fuel gas produced by the second remover 18 is not supplied to the fuel cell 20 through the second fuel gas passage 42 . It is assumed that the used second remover 18 is replaced with a new unused second remover 18 while the first three-way valve 24 and the second three-way valve 26 are in the first state.

In the fuel cell system 2, the controller 50 acquires information on the detected temperature from the temperature sensor 28 at predetermined time intervals (for example, every 5 seconds). Further, the controller 50 acquires information on the detected pressure from the pressure sensor 30 at predetermined time intervals (for example, every 5 seconds). The controller 50 operates based on the detected temperature information obtained from the temperature sensor 28, the detected pressure information obtained from the pressure sensor 30, and the ammonia concentration relation information (see FIG. 2) stored in the storage unit 52. , determine the ammonia concentration at predetermined time intervals (eg, 5 second intervals). For example, when the temperature detected by the temperature sensor 28 is 100° and the pressure detected by the pressure sensor 30 is 0 kPa, the controller 50 controls the reformed gas flowing through the first reformed gas passage 36 based on the ammonia concentration relationship information. Assume that the ammonia concentration in the raw gas is 80%.

As shown in FIG. 3, in S2 of the three-way valve control process, the controller 50 time-integrates the ammonia concentration specified based on the ammonia concentration relationship information (see FIG. 2). As shown in FIG. 4, the controller 50 sequentially adds the ammonia concentration at predetermined time intervals (for example, every 5 seconds).

As shown in FIG. 3, in subsequent S4, the controller 50 determines whether or not the time integrated value of the ammonia concentration has reached a predetermined first integration reference value. If the time integrated value of the ammonia concentration reaches the first integration reference value (if YES), the process proceeds to S6. When the time integrated value of the ammonia concentration reaches the first integration reference value, the controller 50 controls the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to reach the predetermined first reference amount. determined to have reached If the amount of ammonia that can be removed by the first remover 16 is defined as the limit removal amount, the predetermined first reference amount is an amount equal to or less than the limit removal amount. A predetermined first integration reference value is set to a value corresponding to the first reference quantity. The first integration reference value and the first reference amount are obtained in advance based on experiments and analyses, for example.

If the time integrated value of the ammonia concentration does not reach the first integration reference value in S4 (NO), the process returns to S2. When the time integrated value of the ammonia concentration does not reach the first integration reference value, the controller 50 controls the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to reach the predetermined first reference amount. determined not to reach The controller 50 repeatedly performs time integration of the ammonia concentration until the time integration value of the ammonia concentration reaches the first integration reference value.

In S6 after YES in S4, the controller 50 switches the first three-way valve 24 and the second three-way valve 26 from the first state to the second state. When the first three-way valve 24 is switched to the second state, the reformed gas produced in the reformer 14 is supplied to the second remover 18 through the second reformed gas passage 38 . When the first three-way valve 24 is switched to the second state, the reformed gas produced in the reformer 14 is not supplied to the first remover 16 through the first reformed gas passage 36 . Also, when the second three-way valve 26 is switched to the second state, the fuel gas produced by the second remover 18 is supplied to the fuel cell 20 through the second fuel gas passage 42 . When the second three-way valve 26 is switched to the second state, the fuel gas produced by the first remover 16 is not supplied to the fuel cell 20 through the first fuel gas passage 40 .

The used first remover 16 is replaced with a new unused first remover 16 after the process of S6 is executed and before the process of S12, which will be described later, is executed. For example, a user of the fuel cell system 2 replaces the first remover 16 .

In S8 following S6, the controller 50 time-integrates the ammonia concentration specified based on the ammonia concentration relational information in the same manner as in S2 described above. In subsequent S10, the controller 50 determines whether or not the time integral value of the ammonia concentration has reached a predetermined second integral reference value. The predetermined second integration reference value may be the same value as or different from the first integration reference value in S4. If the time integrated value of the ammonia concentration reaches the second integration reference value (YES), the process proceeds to S12. When the time integrated value of the ammonia concentration reaches the second integration reference value, the controller 50 controls the amount of ammonia supplied to the second remover 18 through the second reformed gas passage 38 to reach the predetermined second reference amount. determined to have reached If the amount of ammonia that can be removed by the second remover 18 is defined as the limit removal amount, the predetermined second reference amount is an amount equal to or less than the limit removal amount. A predetermined second integration reference value is set to a value corresponding to the second reference amount. The second integral reference value and the second reference amount are obtained in advance based on experiments and analyses, for example.

If the time integrated value of the ammonia concentration does not reach the second integration reference value in S10 (NO), the process returns to S8. When the time integrated value of the ammonia concentration does not reach the second integration reference value, the controller 50 controls the amount of ammonia supplied to the second remover 18 through the second reformed gas passage 38 to reach the predetermined second reference amount. determined not to reach The controller 50 repeatedly performs time integration of the ammonia concentration until the time integration value of the ammonia concentration reaches the second integration reference value.

In S12 after YES in S10, the controller 50 switches the first three-way valve 24 and the second three-way valve 26 from the second state to the first state. When the first three-way valve 24 is switched to the first state, the reformed gas produced by the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the second three-way valve 26 is switched to the first state, the fuel gas produced by the first remover 16 is supplied to the fuel cell 20 through the first fuel gas passage 40 . After S12, the process returns to the above S2, and the processes from S2 to S12 are repeatedly executed.

After the process of S12 is performed and before the process of S6 described above is performed, the used second remover 18 is replaced with a new unused second remover 18 . For example, a user of the fuel cell system 2 replaces the second remover 18 . Note that the three-way valve control process is appropriately terminated based on, for example, a predetermined termination instruction.

(effect)
The fuel cell system 2 of the first embodiment has been described above. As described above, the fuel cell system 2 includes the temperature sensor 28 that detects the temperature of the reformed gas flowing through the first reformed gas passage 36, and the pressure of the reformed gas that flows through the first reformed gas passage 36. a pressure sensor 30; a first three-way valve 24 provided in a first reformed gas passage 36; and a remover 16 . The first three-way valve 24 has a first state in which the reformed gas is supplied to the first remover 16 through the first reformed gas passage 36 and a first state in which the reformed gas is supplied to the first remover 16 through the first reformed gas passage 36 . is configured to be switchable to a second state in which the voltage is not supplied. When the controller 50 determines that the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 has reached a predetermined first reference amount based on the detection values of the sensors 28 and 30, , the first three-way valve 24 is switched from the first state to the second state (S4, S6). When the integrated value obtained by time-integrating the concentration of ammonia estimated from the temperature detected by the temperature sensor 28 and the pressure detected by the pressure sensor 30 reaches a predetermined first integration reference value, the controller 50 performs the first reforming. It is determined that the amount of ammonia supplied to the first remover 16 through the gas passage 36 has reached the first reference amount (S2, S4). The fuel cell system 2 also includes a fuel cell 20 that uses the fuel gas generated by the first remover 16 to generate electricity.

According to this configuration, when it is determined that the amount of ammonia supplied to the first remover 16 has reached the first reference amount, the first three-way valve 24 is switched from the first state to the second state. The reformed gas can be supplied to the first remover 16 until just before the first remover 16 breaks through. The first reference amount is an amount corresponding to the ammonia removing ability of the first remover 16 . As a result, the first remover 16 can be used to the limit of its ability, and as a result, the replacement frequency of the first remover 16 can be reduced. Moreover, it is possible to prevent the first remover 16 from passing through. Also, by using the temperature sensor 28 and the pressure sensor 30, the amount of ammonia supplied to the first remover 16 can be estimated with high accuracy. As a result, the timing of switching the first three-way valve 24 from the first state to the second state can be accurately controlled. Further, while the first remover 16 is used to the limit of its capacity, it is possible to prevent ammonia contained in the reformed gas from being supplied to the fuel cell 20 due to breakthrough of the first remover 16 .

The fuel cell system 2 also includes a second reformed gas passage 38 branched from the first reformed gas passage 36 via the first three-way valve 24, and a reformed gas passage passing through the second reformed gas passage 38. and a second remover 18 for producing fuel gas by removing ammonia from the fuel gas. The first three-way valve 24 allows reformed gas to be supplied to the first remover 16 through the first reformed gas passage 36, while not supplying reformed gas to the second remover 18 through the second reformed gas passage 38. A first state and a second state in which reformed gas is not supplied to the first remover 16 through the first reformed gas passage 36 but is supplied to the second remover 18 through the second reformed gas passage 38. It is configured to be switchable between states.

According to this configuration, the second remover 18 can be used in place of the first remover 16 at the timing when the first remover 16 has been used to the limit of its ability. Thereby, the fuel cell system 2 can be used continuously and efficiently.

Although one embodiment has been described above, specific aspects are not limited to the above embodiment. In the following description, the same reference numerals are given to the same configurations as those in the above description, and the description thereof is omitted.

(Second embodiment)
Although the fuel cell system 2 of the first embodiment described above includes the first three-way valve 24 and the second three-way valve 26, the configuration is not limited to this. As shown in FIG. 5, in the fuel cell system 2 of the second embodiment, instead of the first three-way valve 24 and the second three-way valve 26, a first on-off valve 60, a second on-off valve 62, and a third on-off valve A valve 64 and a fourth on-off valve 66 are provided.

The first on-off valve 60 is provided in the first reformed gas passage 36 and opens and closes the first reformed gas passage 36 . The first on-off valve 60 is configured to be switchable between an open state (an example of a first state) and a closed state (an example of a second state). When the first on-off valve 60 is open, the reformed gas produced in the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the first on-off valve 60 is closed, the reformed gas produced in the reformer 14 is not supplied to the first remover 16 through the first reformed gas passage 36 . Further, the opening degree of the first on-off valve 60 can be controlled in the open state.

The second on-off valve 62 is provided in the second reformed gas passage 38 and opens and closes the second reformed gas passage 38 . The second reformed gas passage 38 has an upstream end connected to the first reformed gas passage 36 upstream of the first on-off valve 60 , and a downstream end connected to the second remover 18 . The second reformed gas passage 38 branches from the first reformed gas passage 36 upstream of the first on-off valve 60 and downstream of the temperature sensor 28, the pressure sensor 30, and the heat exchanger 31. there is The second on-off valve 62 is configured to be switchable between an open state (an example of a first state) and a closed state (an example of a second state). When the second on-off valve 62 is open, the reformed gas produced by the reformer 14 passes through the first reformed gas passage 36 and the second reformed gas passage upstream of the first on-off valve 60 . 38 to the second remover 18 . When the second on-off valve 62 is closed, the reformed gas produced in the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . Further, the opening degree of the second on-off valve 62 can be controlled in the open state.

The third on-off valve 64 is provided in the first fuel gas passage 40 and opens and closes the first fuel gas passage 40 . The third on-off valve 64 is configured to be switchable between an open state and a closed state. When the third on-off valve 64 is open, the fuel gas produced by the first remover 16 is supplied to the fuel cell 20 through the first fuel gas passage 40 . When the third on-off valve 64 is closed, the fuel gas produced by the first remover 16 is not supplied to the fuel cell 20 through the first fuel gas passage 40 . Further, the opening degree of the third on-off valve 64 can be controlled in the open state.

The fourth on-off valve 66 is provided in the second fuel gas passage 42 and opens and closes the second fuel gas passage 42 . The second fuel gas passage 42 has an upstream end connected to the second remover 18 and a downstream end connected to the first fuel gas passage 40 downstream of the third on-off valve 64 . The second fuel gas passage 42 joins the first fuel gas passage 40 downstream of the third on-off valve 64 . The fourth on-off valve 66 is configured to be switchable between an open state and a closed state. When the fourth on-off valve 66 is open, the fuel gas generated by the second remover 18 passes through the second fuel gas passage 42 and the first fuel gas passage 40 downstream of the third on-off valve 64. It is supplied to the fuel cell 20 . When the fourth on-off valve 66 is closed, the fuel gas produced by the second remover 18 is not supplied to the fuel cell 20 through the second fuel gas passage 42 . Further, the fourth on-off valve 66 is configured so that the degree of opening can be controlled in the open state.

(On-off valve control processing; Fig. 6)
Next, the on-off valve control process of the second embodiment will be described. The on-off valve control process of the second embodiment is started, for example, when the used first remover 16 is replaced with a new unused first remover 16 . When the on-off valve control process of the second embodiment is started, the first on-off valve 60 and the third on-off valve 64 are open, and the second on-off valve 62 and the fourth on-off valve 66 are closed. Suppose there is It is also assumed that the opening degrees of the first on-off valve 60 and the third on-off valve 64 are X (see FIG. 7). When the first on-off valve 60 is open, the reformed gas produced in the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the third on-off valve 64 is open, the fuel gas produced by the first remover 16 is supplied to the fuel cell 20 through the first fuel gas passage 40 . Further, when the second on-off valve 62 is closed, the reformed gas produced in the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . When the fourth on-off valve 66 is closed, the fuel gas produced by the second remover 18 is not supplied to the fuel cell 20 through the second fuel gas passage 42 . It is assumed that the used second remover 18 is replaced with a new unused second remover 18 while the second on-off valve 62 and the fourth on-off valve 66 are closed.

As shown in FIG. 6, in S2 of the on-off valve control process, similarly to S2 of the three-way valve control process of the first embodiment (see FIG. 3), the controller 50 controls the ammonia concentration relation information (see FIG. 2). Integrate the ammonia concentration determined based on the time.

In subsequent S20, the controller 50 determines whether or not the time integral value of the ammonia concentration has reached a predetermined third integral reference value. If the time integrated value of the ammonia concentration reaches the third integration reference value (if YES), the process proceeds to S22. When the time integrated value of the ammonia concentration reaches the third integration reference value, the controller 50 controls the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to reach the predetermined third reference amount. determined to have reached The predetermined third integration reference value in S20 is a value less than the first integration reference value in S4, which will be described later, and the predetermined third reference amount in S20 is an amount less than the first reference amount in S4. The third integral reference value and the third reference amount are obtained in advance based on experiments and analyses, for example.

If the time integrated value of the ammonia concentration does not reach the third integration reference value in S20 (NO), the process returns to S2. When the time integrated value of the ammonia concentration does not reach the third integration reference value, the controller 50 controls the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to reach the predetermined third reference amount. determined not to reach The controller 50 repeatedly performs the time integration of the ammonia concentration until the time integration value of the ammonia concentration reaches the third integration reference value.

In S22 after YES in S20, the controller 50 switches the second on-off valve 62 and the fourth on-off valve 66 from the closed state to the open state. Further, in S22, the controller 50 controls the opening degree of the second on-off valve 62 to an opening degree Y that is less than the opening degree (X) of the first on-off valve 60 (see FIG. 7). Further, the controller 50 controls the degree of opening of the fourth on-off valve 66 to an degree of opening Y that is less than the degree of opening (X) of the third on-off valve 64 (see FIG. 7). The degree of opening of the second on-off valve 62 and the degree of opening of the fourth on-off valve 66 may be the same or different. When the second on-off valve 62 is switched to the open state, the reformed gas produced in the reformer 14 is supplied to the second remover 18 through the second reformed gas passage 38 . When the fourth on-off valve 66 is switched to the open state, the fuel gas produced by the second remover 18 is supplied to the fuel cell 20 through the second fuel gas passage 42 .

In S24 subsequent to S22, the controller 50 time-integrates the ammonia concentration specified based on the ammonia concentration relation information (see FIG. 2) in the same manner as in S2 described above. In subsequent S4, similarly to S4 of the three-way valve control process (see FIG. 3) of the first embodiment, the controller 50 determines whether or not the time integral value of the ammonia concentration has reached a predetermined first integral reference value. to decide. If the time integrated value of the ammonia concentration reaches the first integration reference value (YES), the process proceeds to S26. When the time integrated value of the ammonia concentration reaches the first integration reference value, the controller 50 controls the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to reach the predetermined first reference amount. determined to have reached On the other hand, if the time integrated value of the ammonia concentration does not reach the first integration reference value (NO), the process returns to S24. When the time integrated value of the ammonia concentration does not reach the first integration reference value, the controller 50 controls the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to reach the predetermined first reference amount. determined not to reach The controller 50 repeatedly performs time integration of the ammonia concentration until the time integration value of the ammonia concentration reaches the first integration reference value.

In S26 after YES in S4, the controller 50 increases the opening degrees of the second on-off valve 62 and the fourth on-off valve 66 (see FIG. 7). For example, the controller 50 sets the opening degree of the second on-off valve 62 and the fourth on-off valve 66 to X. The degree of opening of the second on-off valve 62 and the degree of opening of the fourth on-off valve 66 may be the same or different. Further, in S26, the controller 50 switches the first on-off valve 60 and the third on-off valve 64 from the open state to the closed state (see FIG. 7). When the first on-off valve 60 is switched to the closed state, the reformed gas produced in the reformer 14 is not supplied to the first remover 16 through the first reformed gas passage 36 . When the third on-off valve 64 is switched to the closed state, the fuel gas produced by the first remover 16 is not supplied to the fuel cell 20 through the first fuel gas passage 40 .

The used first remover 16 is replaced with a new unused first remover 16 after the process of S26 is executed and before the process of S30, which will be described later, is executed. For example, a user of the fuel cell system 2 replaces the first remover 16 .

In S8 following S26, the controller 50 time-integrates the ammonia concentration specified based on the ammonia concentration relational information in the same manner as in S2 described above. In subsequent S28, the controller 50 determines whether or not the time integral value of the ammonia concentration has reached a predetermined fourth integral reference value. If the time integrated value of the ammonia concentration reaches the fourth integration reference value (YES), the process proceeds to S30. When the time integrated value of the ammonia concentration reaches the fourth integration reference value, the controller 50 controls the amount of ammonia supplied to the second remover 18 through the second reformed gas passage 38 to reach the predetermined fourth reference amount. determined to have reached The predetermined fourth integration reference value in S28 is less than the second integration reference value in S10, which will be described later, and the predetermined fourth reference amount in S28 is less than the second reference amount in S10. The fourth integral reference value and the fourth reference amount are obtained in advance based on experiments and analyses, for example.

If the time integrated value of the ammonia concentration does not reach the fourth integration reference value in S28 (NO), the process returns to S8. When the time integrated value of the ammonia concentration does not reach the fourth integration reference value, the controller 50 controls the amount of ammonia supplied to the second remover 18 through the second reformed gas passage 38 to reach the predetermined fourth reference amount. determined not to reach The controller 50 repeatedly performs the time integration of the ammonia concentration until the time integration value of the ammonia concentration reaches the fourth integration reference value.

In S30 after YES in S28, the controller 50 switches the first on-off valve 60 and the third on-off valve 64 from the closed state to the open state. Further, in S30, the controller 50 controls the opening degree of the first on-off valve 60 to an opening degree Y that is less than the opening degree (X) of the second on-off valve 62 (see FIG. 7). Further, the controller 50 controls the degree of opening of the third on-off valve 64 to an degree of opening Y that is less than the degree of opening (X) of the fourth on-off valve 66 . The degree of opening of the first on-off valve 60 and the degree of opening of the third on-off valve 64 may be the same or different. When the first on-off valve 60 is switched to the open state, the reformed gas produced in the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the third on-off valve 64 is switched to the open state, the fuel gas produced by the first remover 16 is supplied to the fuel cell 20 through the first fuel gas passage 40 .

In S32 subsequent to S30, the controller 50 time-integrates the ammonia concentration specified based on the ammonia concentration relationship information (see FIG. 2) in the same manner as in S8 described above. In subsequent S10, similarly to S10 of the three-way valve control process (see FIG. 3) of the first embodiment, the controller 50 determines whether or not the time integral value of the ammonia concentration has reached a predetermined second integral reference value. to decide. If the time integrated value of the ammonia concentration reaches the second integration reference value (YES), the process proceeds to S34. When the time integrated value of the ammonia concentration reaches the second integration reference value, the controller 50 controls the amount of ammonia supplied to the second remover 18 through the second reformed gas passage 38 to reach the predetermined second reference amount. determined to have reached On the other hand, if the time integrated value of the ammonia concentration does not reach the second integration reference value (NO), the process returns to S32. When the time integrated value of the ammonia concentration does not reach the second integration reference value, the controller 50 controls the amount of ammonia supplied to the second remover 18 through the second reformed gas passage 38 to reach the predetermined second reference amount. determined not to reach The controller 50 repeatedly performs time integration of the ammonia concentration until the time integration value of the ammonia concentration reaches the second integration reference value.

In S34 after YES in S10, the controller 50 increases the opening degrees of the first on-off valve 60 and the third on-off valve 64 (see FIG. 7). For example, the controller 50 sets the opening degree of the first on-off valve 60 and the third on-off valve 64 to X. The opening degrees of the first on-off valve 60 and the third on-off valve 64 may be the same or different. Also, in S34, the controller 50 switches the second on-off valve 62 and the fourth on-off valve 66 from the open state to the closed state (see FIG. 7). When the second on-off valve 62 is switched to the closed state, the reformed gas produced in the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . When the fourth on-off valve 66 is switched to the closed state, the fuel gas produced by the second remover 18 is not supplied to the fuel cell 20 through the second fuel gas passage 42 . After S34, the process returns to S2, and the processes from S2 to S34 are repeatedly executed.

After the process of S34 is performed and before the process of S22 described above is performed, the used second remover 18 is replaced with a new unused second remover 18 . For example, a user of the fuel cell system 2 replaces the second remover 18 . It should be noted that the on-off valve control process is appropriately terminated based on, for example, a predetermined termination instruction.

(effect)
The fuel cell system 2 of the second embodiment has been described above. As described above, the fuel cell system 2 includes the first reformed gas passage 36 , the first on-off valve 60 provided in the first reformed gas passage 36 , and the first valve upstream of the first on-off valve 60 . A second reformed gas passage 38 branched from the reformed gas passage 36 and a second on-off valve 62 provided in the second reformed gas passage 38 are provided. Each of the first on-off valve 60 and the second on-off valve 62 is configured to be switchable between an open state and a closed state. When the controller 50 determines that the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 has reached a predetermined third reference amount based on the detection values of the sensors 28 and 30, , the second on-off valve 62 is switched from the closed state to the open state, and the degree of opening of the second on-off valve 62 is controlled to be less than the degree of opening of the first on-off valve 60 (S20, S22). When the integrated value obtained by time-integrating the concentration of ammonia estimated from the temperature detected by the temperature sensor 28 and the pressure detected by the pressure sensor 30 reaches a predetermined first integration reference value, the controller 50 performs the first reforming. It is determined that the amount of ammonia supplied to the first remover 16 through the gas passage 36 has reached the first reference amount (S2, S20).

According to this configuration, it is possible to provide a period during which the first remover 16 and the second remover 18 are used in parallel. As a result, when switching from the first remover 16 to the second remover 18, the flow of the reformed gas can be smoothly switched without interruption.

After controlling the opening of the second on-off valve 62 to be less than the opening of the first on-off valve 60, the controller 50 controls the opening of the first reformed gas through the first reformed gas passage 36 based on the detection values of the sensors 28 and 30. When it is determined that the amount of ammonia supplied to the remover 16 has reached the predetermined first reference amount, the degree of opening of the second on-off valve 62 is increased (S24, S4, S26). According to this configuration, it is possible to smoothly switch to the second remover 18 at the timing when the first remover 16 is used to the limit of its ability.

(Third embodiment)
Although the fuel cell system 2 of the second embodiment described above includes the first on-off valve 60 and the second on-off valve 62, the configuration is not limited to this. As shown in FIG. 8, the fuel cell system 2 of the third embodiment includes a first pump 80 and a second pump 82 instead of the first on-off valve 60 and the second on-off valve 62 .

The first pump 80 is provided in the first reformed gas passage 36 and pumps the reformed gas from the upstream side to the downstream side of the first reformed gas passage 36 . The first pump 80 is configured to be switchable between an operating state and a stopped state. When the first pump 80 is in operation, the reformed gas produced in the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . When the first pump 80 is in a stopped state, the reformed gas produced by the reformer 14 is not supplied to the first remover 16 through the first reformed gas passage 36 . The first pump 80 is configured to be output controllable in an operating state.

The second pump 82 is provided in the second reformed gas passage 38 and pumps the reformed gas from the upstream side to the downstream side of the second reformed gas passage 38 . The second pump 82 is configured to be switchable between an operating state and a stopped state. When the second pump 82 is in operation, the reformed gas produced in the reformer 14 is supplied to the second remover 18 through the second reformed gas passage 38 . When the second pump 82 is in a stopped state, the reformed gas produced by the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . The second pump 82 is configured to be output controllable in an operating state.

(Pump control processing; FIG. 9)
Next, the pump control processing of the third embodiment will be explained. As shown in FIG. 9, in the pump control process, S42, S46, S50 and S54 are performed instead of S22, S26, S30 and S34 of the on-off valve control process (see FIG. 6) of the second embodiment. Processing is performed. It is assumed that the first pump 80 is in an operating state and the second pump 82 is in a stopped state when the pump control process of the third embodiment is started. Assume that the output of the first pump 80 is V (see FIG. 10). In the following, description of the same processing as the on-off valve control processing (see FIG. 6) in the pump control processing will be omitted.

In S42 of the pump control process, the controller 50 switches the second pump 82 from the stopped state to the operating state. Also, in S42, the controller 50 controls the output of the second pump 82 to an output W less than the output (V) of the first pump 80 (see FIG. 10). When the second pump 82 is switched to the operating state, the reformed gas produced in the reformer 14 is supplied to the second remover 18 through the second reformed gas passage 38 . In addition, in S42, the controller 50 switches the fourth on-off valve 66 from the closed state to the open state, as in S22 (see FIG. 6). Further, the controller 50 controls the degree of opening of the fourth on-off valve 66 to an degree of opening Y that is less than the degree of opening (X) of the third on-off valve 64 (see FIG. 7).

At S46 shown in FIG. 9, the controller 50 increases the output of the second pump 82 (see FIG. 10). For example, controller 50 drives the output of second pump 82 to V. Also, in S46, the controller 50 switches the first pump 80 from the operating state to the stopped state (see FIG. 10). When the first pump 80 is switched to the stopped state, the reformed gas produced in the reformer 14 is not supplied to the first remover 16 through the first reformed gas passage 36 . In addition, in S46, the controller 50 increases the opening degree of the fourth on-off valve 66 (see FIG. 7), as in S26 (see FIG. 6). Also, the controller 50 switches the third on-off valve 64 from the open state to the closed state.

In S50 shown in FIG. 9, the controller 50 switches the first pump 80 from the stopped state to the operating state. Also, in S50, the controller 50 controls the output of the first pump 80 to an output W less than the output (V) of the second pump 82 (see FIG. 10). When the first pump 80 is switched to the operating state, the reformed gas produced in the reformer 14 is supplied to the first remover 16 through the first reformed gas passage 36 . Note that in S50, the controller 50 switches the third on-off valve 64 from the closed state to the open state, as in S30 (see FIG. 6). Further, the controller 50 controls the degree of opening of the third on-off valve 64 to an degree of opening Y that is less than the degree of opening (X) of the fourth on-off valve 66 (see FIG. 7).

At S54 shown in FIG. 9, the controller 50 increases the output of the first pump 80 (see FIG. 10). For example, the controller 50 drives the output of the first pump 80 to V. Also, in S54, the controller 50 switches the second pump 82 from the operating state to the stopped state (see FIG. 10). When the second pump 82 is switched to the stopped state, the reformed gas produced in the reformer 14 is not supplied to the second remover 18 through the second reformed gas passage 38 . In addition, in S54, the controller 50 increases the degree of opening of the third on-off valve 64 (see FIG. 7), as in S34 (see FIG. 6). Also, the controller 50 switches the fourth on-off valve 66 from the open state to the closed state.

(effect)
The fuel cell system 2 of the third embodiment has been described above. As described above, the fuel cell system 2 includes the first pump 80 provided in the first reformed gas passage 36 . When the controller 50 determines that the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 has reached a predetermined first reference amount based on the detection values of the sensors 28 and 30, , the first pump 80 is switched from the operating state to the stopped state. According to this configuration, as in the fuel cell systems 2 of the first and second embodiments, the first remover 16 can be used to the limit of its capacity, and the replacement frequency of the first remover 16 can be reduced. can do.

The fuel cell system 2 also includes a second pump 82 provided in the second reformed gas passage 38 . When the controller 50 determines that the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 has reached a predetermined third reference amount based on the detection values of the sensors 28 and 30, , the second pump 82 is switched from the stopped state to the operating state, and the output of the second pump 82 is controlled to be less than the output of the first pump 80 . According to this configuration, similarly to the fuel cell system 2 of the second embodiment, when switching from the first remover 16 to the second remover 18, the flow of the reformed gas is smoothly switched without interruption. can be done.

(Modification)
(1) In some embodiments, a temperature sensor 28 may be provided between the heat exchanger 31 and the first three-way valve 24 . The temperature sensor 28 may detect the temperature of the reformed gas flowing through the first reformed gas passage 36 downstream of the heat exchanger 31 and upstream of the first three-way valve 24 . That is, the temperature sensor 28 may detect the temperature of the reformed gas after heat exchange by the heat exchanger 31 .

(2) In some embodiments, a pressure sensor 30 may be provided between the heat exchanger 31 and the first three-way valve 24 . The pressure sensor 30 may detect the pressure of the reformed gas flowing through the first reformed gas passage 36 downstream of the heat exchanger 31 and upstream of the first three-way valve 24 . That is, the pressure sensor 30 may detect the pressure of the reformed gas after heat exchange by the heat exchanger 31 .

(Fourth embodiment)
Although the fuel cell system 2 described above has a configuration including the temperature sensor 28 and the pressure sensor 30, it is not limited to this configuration. Further, the fuel cell system 2 described above has a configuration in which the ammonia concentration is integrated over time, but the present invention is not limited to this configuration. The fuel cell system 2 of the fourth embodiment has a flow rate sensor 70 as shown in FIG. The flow rate sensor 70 is provided in the first reformed gas passage 36 on the upstream side of the first three-way valve 24, and detects the reformed gas flowing through the first reformed gas passage 36 on the upstream side of the first three-way valve 24. to detect the flow rate of The controller 50 switches the first three-way valve 24 from the first state to the second state when the time integral value of the flow rate detected by the flow rate sensor 70 reaches a predetermined integral reference value. The controller 50 reduces the amount of ammonia supplied to the first remover 16 through the first reformed gas passage 36 to the first It is determined that the reference amount has been reached (see S4 and S6 in FIG. 3). The same applies to the second reference amount, the third reference amount, and the fourth reference amount. The same applies to the configuration in which the fuel cell system 2 includes the first on-off valve 60 and the second on-off valve 62 instead of the first three-way valve 24 . The same applies to a configuration in which the fuel cell system 2 includes a first pump and a second pump. The first, second, third, and fourth distinctions in the specification are for the sake of convenience.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or in the drawings exhibit technical utility either singly or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or drawings can simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

2: fuel cell system, 10: raw material tank, 12: vaporizer, 14: reformer, 15: heater, 16: first remover, 18: second remover, 20: fuel cell, 22: pump, 24: first three-way valve, 26: second three-way valve, 28: temperature sensor, 30: pressure sensor, 32: liquid passage, 34: source gas passage, 36: first reformed gas passage, 38: second reformed gas passage Gas passage 40: First fuel gas passage 42: Second fuel gas passage 44: Air passage 46: Exhaust gas passage 50: Controller 52: Storage unit 60: First on-off valve 62: Second On-off valve 64: Third on-off valve 66: Fourth on-off valve 70: Flow rate sensor 80: First pump 82: Second pump

Claims (8)

a reformer for generating a reformed gas by reforming the raw material gas;
a first reformed gas passage through which the reformed gas generated by the reformer flows;
a sensor for detecting the state of the reformed gas flowing through the first reformed gas passage;
a first valve provided in the first reformed gas passage;
a first remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the first reformed gas passage;
a control unit;
The first valve has a first state in which reformed gas is supplied to the first remover through the first reformed gas passage, and a first state in which reformed gas is supplied to the first remover through the first reformed gas passage. is configured to be switchable between a second state in which it is not supplied,
When the controller determines that the amount of ammonia supplied to the first remover through the first reformed gas passage has reached a predetermined first reference amount based on the detected value of the sensor, An ammonia removal system, wherein a first valve is switched from said first state to said second state. The ammonia removal system of claim 1, comprising:
The sensor includes a temperature sensor that detects the temperature of the reformed gas flowing through the first reformed gas passage, and a pressure sensor that detects the pressure of the reformed gas flowing through the first reformed gas passage,
When the integrated value obtained by time-integrating the ammonia concentration estimated from the detected value of the temperature sensor and the detected value of the pressure sensor reaches a predetermined first integration reference value, the control unit performs the first revision. The ammonia removal system, wherein the ammonia removal system determines that the amount of ammonia supplied to the first remover through the quality gas passage has reached the first reference amount. The ammonia removal system according to claim 1 or 2,
a second reformed gas passage branched from the first reformed gas passage through the first valve and through which the reformed gas produced by the reformer flows;
a second remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the second reformed gas passage;
The first valve is configured such that the reformed gas is supplied to the first remover through the first reformed gas passage and the reformed gas is not supplied to the second remover through the second reformed gas passage. the first state and the second state in which reformed gas is not supplied to the first remover through the first reformed gas passage and reformed gas is supplied to the second remover through the second reformed gas passage. An ammonia removal system configured to be switchable between two states. The ammonia removal system according to claim 1 or 2,
a second reformed gas passage branched from the first reformed gas passage on the upstream side of the first valve and through which the reformed gas generated by the reformer flows;
a second valve provided in the second reformed gas passage;
a second remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the second reformed gas passage;
The second valve has a first state in which reformed gas is supplied to the second remover through the second reformed gas passage, and a first state in which reformed gas is supplied to the second remover through the second reformed gas passage. is configured to be switchable between a second state in which it is not supplied,
The controller determines that the amount of ammonia supplied to the first remover through the first reformed gas passage has reached a predetermined third reference amount that is less than the first reference amount based on the detection value of the sensor. and switching the second valve from the second state to the first state and controlling the degree of opening of the second valve to be less than the degree of opening of the first valve. An ammonia removal system according to claim 4, wherein
After controlling the degree of opening of the second valve to be less than the degree of opening of the first valve, the controller controls the opening degree of the second valve to the first remover through the first reformed gas passage based on the detection value of the sensor. An ammonia removal system that increases the degree of opening of the second valve when it is determined that the amount of supplied ammonia has reached the predetermined first reference amount. a reformer for generating a reformed gas by reforming the raw material gas;
a first reformed gas passage through which the reformed gas generated by the reformer flows;
a sensor for detecting the state of the reformed gas flowing through the first reformed gas passage;
a first pump provided in the first reformed gas passage;
a first remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the first reformed gas passage;
a control unit;
The first pump is configured to supply the reformed gas to the first remover through the first reformed gas passage by pumping the reformed gas, and to supply the reformed gas to the first remover through the first reformed gas passage. It is configured to be switchable between a stopped state in which no reformed gas is supplied to the device,
When the controller determines that the amount of ammonia supplied to the first remover through the first reformed gas passage has reached a predetermined first reference amount based on the detected value of the sensor, An ammonia removal system, wherein the first pump is switched from said operating state to said stopped state. An ammonia removal system according to claim 6, comprising:
a second reformed gas passage branched from the first reformed gas passage on the upstream side of the first pump and through which the reformed gas generated by the reformer flows;
a second pump provided in the second reformed gas passage;
a second remover for generating fuel gas by removing ammonia from the reformed gas that has passed through the second reformed gas passage;
The second pump is configured to supply the reformed gas to the second remover through the second reformed gas passage by pumping the reformed gas, and to supply the second remover through the second reformed gas passage. It is configured to be switchable between a stopped state in which no reformed gas is supplied to the device,
The controller controls the amount of ammonia supplied to the first remover through the first reformed gas passage to reach a predetermined third reference amount, which is less than the predetermined first reference amount, based on the detection value of the sensor. and switching the second pump from the stopped state to the operating state and controlling the output of the second pump to be less than the output of the first pump when it is determined that the ammonia removal system. an ammonia removal system according to any one of claims 1 to 7;
and a fuel cell that generates power using the fuel gas generated by the first remover.

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