JP6772888B2 - Fuel gas supply method - Google Patents

Description

The present invention relates to a fuel gas supply method.

A technique is known in which impurities in a fuel gas are adsorbed on an adsorber to supply a fuel gas having a low concentration of impurities to a supply target. It is known that such an adsorber adsorbs impurities in the fuel gas at the first temperature, and desorbs the adsorbed impurities into the regenerated gas at a second temperature higher than the first temperature. Further, using two such adsorbers, one of the two adsorbers adsorbs impurities and the other desorbs impurities, and one desorbs impurities and the other adsorbs impurities. It is known that a fuel gas having a low concentration of impurities is continuously supplied to a supply target by alternately switching between and (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-284875

However, depending on how the adsorber is switched, the period during which the fuel gas having a low concentration of impurities is supplied to the supply target may be shortened.

An object of the present invention is to provide a fuel gas supply method that secures a period during which a fuel gas having a low concentration of impurities is supplied to a supply target.

The above purpose is to provide first and second removers that adsorb impurities in the supplied fuel gas at the first temperature and desorb the adsorbed impurities into the regenerated gas at a second temperature higher than the first temperature. In a fuel gas supply method for supplying the fuel gas having a low concentration of impurities to the supply target, the fuel gas is supplied to the supply target through the first remover having the first temperature. While the regenerated gas passes through the second remover at the second temperature and is discharged to other than the supply target, the fuel gas passes through the second remover and is not the supply target. The step of switching to the second state of being discharged to the second state, the step of switching from the second state to the third state in which the regenerated gas passes through the first remover and is discharged to other than the supply target, and the second state. The step of lowering the temperature of the remover, and when the second remover is lowered to a third temperature higher than the first temperature and lower than the second temperature, the fuel gas is released from the third state. This can be achieved by a fuel gas supply method including a step of switching to the fourth state of passing through the second remover and being supplied to the supply target.

According to the present invention, it is possible to provide a fuel gas supply method in which a period during which a fuel gas having a low concentration of impurities is supplied to a supply target is secured.

FIG. 1 is a block diagram of a fuel gas supply system. FIG. 2 is a block diagram of the removal system. FIG. 3A is a graph showing a change in the ammonia concentration in the fuel gas at the outlet of the remover according to the temperature of the remover which has sufficiently desorbed new products or impurities and completed regeneration, and FIG. 3B is a graph showing a change in the ammonia concentration in the fuel gas. It is a graph which showed the time change of the ammonia concentration in the fuel gas at the outlet of a remover with the remover maintained at a 1st temperature. 4A and 4B are diagrams showing the first and second states having different distribution channels, respectively. 5A and 5B are diagrams showing the third and fourth states having different distribution channels, respectively. FIG. 6 is an example of a flowchart of switching control executed by the control unit. FIG. 7A is an example of a time chart showing the temperature change of the remover due to the switching control from the first state to the fourth state in this embodiment, and FIG. 7B is an example of the time chart from the first state to the fourth state in the comparative example. This is an example of a time chart showing the temperature change of the remover due to the control of switching to four states.

FIG. 1 is a block diagram of the fuel gas supply system 1. The fuel gas supply system 1 includes a fuel tank 2, a vaporizer 4, a reformer 6, heat exchangers 8 and 10, a removal system 12, and a fuel cell 14. The fuel cell 14 receives the supply of the oxidant gas and the fuel gas to generate electricity. The oxidant gas is supplied to the fuel cell 14 via an air compressor (not shown).

Liquid raw fuel is stored in the fuel tank 2. The raw material is, for example, a raw material for hydrocarbons such as city gas, propane gas, naphtha, gasoline, kerosene, or an alcohol-based raw material such as methanol. Raw fuel is supplied to the vaporizer 4 via a pump (not shown), and further, high-temperature cooling water described later passes through the vaporizer 4, and a part of the raw fuel is vaporized.

In the reformer 6, fuel gas is generated by the steam reforming reaction between steam and raw fuel. The reformer 6 is provided with a reforming catalyst that promotes the steam reforming reaction, and air is supplied from the outside to promote the oxidation reaction on the reforming catalyst. When the raw fuel is reformed by the reformer 6, ammonia is produced as a by-product, and the produced fuel gas contains ammonia. Further, even when liquid ammonia is used as the raw material, the fuel gas reformed by the reformer 6 contains ammonia.

In the heat exchanger 8, heat exchange between the fuel gas and air having a lower temperature is performed, whereby the temperature of the fuel gas is lowered and the temperature of the air is raised. In the heat exchanger 10, heat exchange between the fuel gas and the cooling water having a lower temperature is performed, whereby the temperature of the fuel gas is lowered and the temperature of the cooling water is raised. The fuel gas from which the excessively high temperature is suppressed and the air heated by the heat exchanger 8 are supplied to the removal system 12. The cooling water reaches a high temperature by passing through the heat exchanger 10, and then passes through the vaporizer 4 to vaporize the raw material fuel gas. The cooling water may be, for example, for cooling the fuel cell 14.

The removal system 12 removes ammonia, which is an impurity in the fuel gas. The fuel gas from which ammonia has been removed is supplied to the fuel cell 14 and used for power generation of the fuel cell 14.

FIG. 2 is a block diagram of the removal system 12. The removal system 12 includes a fuel gas passage 20 through which the fuel gas passes and an air passage 30 through which the hot air passes. Upstream branch paths 21 and 22 are connected to the downstream end of the fuel gas passage 20 via a three-way valve V1. The first remover E1 and the second remover E2 are connected to the downstream ends of the upstream branch paths 21 and 22, respectively. The first remover E1 and the second remover E2 are connected to the upstream ends of the downstream branch paths 23 and 24, respectively. A supply branch path 25 and an exhaust branch path 33 are connected to the downstream end of the downstream branch path 23 via a three-way valve V3. A supply branch path 26 and an exhaust branch path 34 are connected to the downstream end of the downstream branch path 24 via a three-way valve V4. A single supply junction 27 is connected to the downstream ends of the supply branch paths 25 and 26. A fuel cell 14 is connected to the downstream end of the supply junction flow path 27. Air branch passages 31 and 32 are connected to the downstream end of the air passage 30 via a three-way valve V2. The downstream ends of the air branch paths 31 and 32 are connected to the upstream branch paths 21 and 22, respectively. The downstream ends of the exhaust branch paths 33 and 34 are connected to a single exhaust junction flow path 35. The downstream end of the exhaust gas flow path 35 is exposed to the outside air.

Pumps P1 and P2 are provided in the middle of the fuel gas passage 20 and the air passage 30, respectively. Check valves C1 and C2 are provided in the air branch paths 31 and 32, respectively. The check valve C1 allows air to flow from the air passage 30 side to the upstream branch road 21 side, but regulates the opposite. Similarly, the check valve C2 allows air to flow from the air passage 30 side to the upstream branch road 22 side, but regulates the opposite. The first remover E1 and the second remover E2 are provided with temperature sensors S1 and S2, respectively.

The pumps P1 and P2, the three-way valves V1 to V4, and the temperature sensors S1 and S2 are electrically connected to the control unit 100, and the control unit 100 controls the operations of the pumps P1 and P2 and the three-way valves V1 to V4. At the same time, the temperatures of the first remover E1 and the second remover E2 are calculated based on the detection signals of the temperature sensors S1 and S2, respectively. The control unit 100 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a storage device, and the like. The control unit 100 can control the heat exchanger 8 to control the temperature of the air supplied to the removal system 12.

The first remover E1 includes an adsorbent that adsorbs ammonia, which is an impurity in the fuel gas. Examples of the adsorbent include activated carbon and zeolite. The first remover E1 adsorbs ammonia in the passing fuel gas at a temperature T1 and desorbs the adsorbed ammonia into the regenerated gas at a temperature T2 higher than the temperature T1. The high temperature air supplied to the removal system 12 described above is used as a regenerated gas. The same applies to the second remover E2.

FIG. 3A is a graph showing the change in the ammonia concentration in the fuel gas at the outlet of the first remover E1 according to the temperature of the first remover E1 which has sufficiently desorbed new products or impurities and completed regeneration. is there. As shown in FIG. 3A, it is shown that the temperature of the first remover E1 is the temperature T1 and the ammonia concentration is low, so that ammonia can be adsorbed efficiently. On the other hand, the higher the temperature of the first remover E1, the lower the adsorption efficiency of ammonia. The temperature T2, which is higher than the temperature T1, is a temperature at which the ammonia adsorbed on the first remover E1 is desorbed into the air which is the regenerated gas. At temperature T2, the ability to adsorb ammonia is low. Further, the allowable upper limit concentration α of ammonia that the fuel cell 14 can tolerate is the ammonia concentration at the temperature T3 that is higher than the temperature T1 and lower than the temperature T2, and if it is a new or regenerated remover, it is higher than the temperature T1. Even at a high temperature T3, the fuel gas after passing can be supplied to the fuel cell. The temperature T3 has been obtained experimentally in advance. The second remover E2 is the same as above. The temperatures T1, T2, and T3 are examples of the first, second, and third temperatures, respectively. The temperature T3 will be described later.

FIG. 3B is a graph showing the time change of the ammonia concentration in the fuel gas at the outlet of the first remover E1 while the first remover E1 is maintained at the temperature T1. Approximately, as time passes, the ammonia concentration increases, and the adsorption capacity of the first remover E1 decreases. In particular, the ammonia concentration can be efficiently reduced in the period until the time tα when the ammonia concentration reaches the allowable upper limit concentration α. By controlling the temperature of the remover so that the temperature of the remover reaches T1 by the time tα is reached, the fuel gas having a low ammonia concentration can be supplied to the fuel cell. Further, even after the ammonia adsorption capacity is reduced, the adsorption capacity is regenerated after the first remover E1 is maintained at the temperature T2 to desorb the ammonia. The same applies to the second remover E2.

In this embodiment, one of the first remover E1 and the second remover E2 adsorbs ammonia in the fuel gas and the other desorbs the adsorbed ammonia, and one desorbs the adsorbed ammonia and the other desorbs the adsorbed ammonia. The fuel gas is supplied to the fuel cell 14 while being switched from the state of adsorbing ammonia in the fuel gas at predetermined time intervals. As a result, the fuel gas having a low ammonia concentration can be continuously supplied to the fuel cell 14. Details will be described later.

The temperature of the fuel gas supplied to the removal system 12 is the vaporizer 4 and the heat exchanger so that the temperature of the first remover E1 or the second remover E2 through which the fuel gas passes is maintained at the temperature T1. The amount of heat received in 8 and 10 is adjusted. Further, the temperature of the air supplied to the removal system 12 is a heat exchanger so that the temperature of the first remover E1 or the second remover E2 through which the air passes is maintained at the temperature T2, except for the case described later. The amount of heat received in 8 is adjusted.

In the removal system 12, the path through which fuel gas and air flow is switched according to the state of the three-way valves V1 to V4 controlled by the control unit 100. 4A to 5B are diagrams showing the first to fourth states having different distribution channels. In FIGS. 4A to 5B, the fuel gas flow direction GF and the air flow direction AF are indicated by arrows, respectively.

As shown in FIG. 4A, in the first state, the three-way valve V1 communicates the fuel gas passage 20 with the upstream branch passage 21 and closes the upstream branch passage 22, and the three-way valve V3 communicates with the downstream branch passage 23 and the supply branch passage 25. The exhaust branch passage 33 is closed. As a result, the fuel gas is supplied to the fuel cell 14 through the fuel gas passage 20, the upstream branch passage 21, the first remover E1, the downstream branch passage 23, the supply branch passage 25, and the supply junction passage 27 in this order. Therefore, in the first state, the concentration of ammonia in the fuel gas is reduced by the first remover E1. Further, in the first state, the three-way valve V2 communicates the air passage 30 and the air branch passage 32 to close the air branch passage 31, and the three-way valve V4 communicates the downstream branch passage 24 and the exhaust branch passage 34 to supply and branch. Road 26 is closed. As a result, the air heated by the heat exchanger 8 becomes the air passage 30, the air branch path 32, the upstream branch path 22, the second remover E2, the downstream branch path 24, the exhaust branch path 34, and the exhaust junction channel 35. It is distributed in order and exhausted to the outside. Therefore, in the first state, the desorption of ammonia from the second remover E2 is promoted by the hot air.

As shown in FIG. 4B, in the second state, the three-way valve V1 is the same as in the first state, but the three-way valve V3 communicates the downstream branch path 23 and the exhaust branch path 33 and closes the supply branch path 25. As a result, the fuel gas is circulated in the order of the fuel gas passage 20, the upstream branch path 21, the first remover E1, the downstream branch path 23, the exhaust branch path 33, and the exhaust combined flow path 35, and is supplied to the fuel cell 14. It is exhausted to the outside without. The three-way valves V2 and V4 are the same as in the first state.

As shown in FIG. 5A, in the third state, the three-way valves V3 and V4 are the same as in the second state, but the three-way valve V1 connects the fuel gas passage 20 and the upstream branch passage 22 and closes the upstream branch passage 21. , The three-way valve V2 communicates the air passage 30 and the air branch passage 31 and closes the air branch passage 32. As a result, the fuel gas circulates in the order of the fuel gas passage 20, the upstream branch passage 22, the second remover E2, the downstream branch passage 24, the exhaust branch passage 34, and the exhaust combined passage 35, and is exhausted to the outside. Further, the air circulates in the order of the air passage 30, the air branch path 31, the upstream branch path 21, the first remover E1, the downstream branch path 23, the exhaust branch path 33, and the exhaust combined flow path 35, and is exhausted to the outside. As described above, in the third state, unlike the first and second states, the fuel gas passes through the second remover E2 and the air passes through the first remover E1.

As shown in FIG. 5B, in the fourth state, the three-way valves V1, V2, and V3 are the same as in the third state, but the three-way valve V4 communicates the downstream branch path 24 and the supply branch path 26 and exhaust branch path 34. To close. As a result, the fuel gas circulates in the order of the fuel gas passage 20, the upstream branch passage 22, the second remover E2, the downstream branch passage 24, the supply branch passage 26, and the supply junction passage 27, and is supplied to the fuel cell 14.

As described above, the first state is the state in which the first remover E1 adsorbs the ammonia in the fuel gas and the ammonia adsorbed by the second remover E2 is desorbed, and the fourth state is the first removal. Ammonia adsorbed by the vessel E1 is desorbed, and the second remover E2 is adsorbing ammonia in the fuel gas. Such switching between the first and fourth states is switched from the first state to the second, third, and fourth states by the control unit 100, or from the fourth state to the third, second, and fourth states. It can be switched in the order of one state.

FIG. 6 is an example of a flowchart of switching control executed by the control unit 100. The control unit 100 repeatedly executes this control at predetermined intervals. First, it is determined whether or not the switching timing requires switching between the first remover E1 and the second remover E2 (step S1). The switching timing is determined by whether or not the above-mentioned time tα has elapsed since the end of the previous switching. In the case of a negative determination, this control ends.

In the case of affirmative determination, switching is started and the heat exchanger 8 is controlled so that the temperature of the air supplied to the removal system 12 decreases (step S3). As a result, in the heat exchanger 8, the temperature of the second remover E2 becomes lower than the temperature T2 from the state where the temperature of the air is controlled so that the temperature of the second remover E2 is maintained at the temperature T2. Be controlled. Therefore, the temperature of the second remover E2 starts to decrease from the temperature T2. Step S3 is an example of a step of lowering the temperature of the second remover E2. The temperature of the second remover E2 may be lowered by controlling the flow rate of the air supplied to the second remover E2 to be small and utilizing the natural heat dissipation from the outside air.

Next, it is determined whether or not the current state is the first state (step S5). In the case of affirmative determination, control for switching from the first state to the fourth state is executed. Specifically, the first state is switched to the second state (step S7a), and then the second state is switched to the third state (step S9a). Specifically, from the first state, the three-way valve V3 is controlled first, and the fuel gas is switched to the second state in which the fuel gas is exhausted to the outside via the exhaust branch path 33 and the exhaust junction flow path 35, and the second state is switched to the three-way valve. The valve V2 is controlled to switch to a third state in which air is exhausted to the outside via the upstream branch passage 21 and the downstream branch passage 23. For example, if the three-way valve V2 is controlled before the three-way valve V3 is controlled from the first state and air flows through the upstream branch path 21 and the downstream branch path 23, the air may flow into the fuel cell 14 together with the fuel gas. .. In this embodiment, as described above, the three-way valve V3 is first controlled so that the fuel gas is not supplied to the fuel cell 14, and then the three-way valve V2 is controlled, so that air is supplied to the fuel cell 14. Is prevented. Step S7a is an example of a step of switching from the first state to the second state in which the fuel gas passes through the second remover E2 and is discharged to other than the fuel cell 14. Step S9a is an example of a step of switching from the second state to the third state in which the regenerated gas passes through the first remover E1 and is discharged to other than the fuel cell 14.

Next, in the third state, the heat exchanger 8 is controlled so that the temperature of the air returns to the original temperature (step S11a). As a result, high-temperature air passes through the first remover E1 and the temperature of the first remover E1 begins to rise. Further, the fuel gas passes through the second remover E2 and the temperature is further lowered.

Next, it is determined whether or not the temperature of the second remover E2 has dropped to less than the temperature T3 (step S13a). The temperature of the second remover E2 is calculated based on the detected value of the temperature sensor S2. In the case of a negative determination, step S13a is executed again. In the case of an affirmative determination, the state is switched to the fourth state (step S15a), and the switching control ends. As a result, the supply of the fuel gas that has passed through the second remover E2 to the fuel cell 14 is started.

Here, as described above, the temperature of the fuel gas is controlled so that the temperature of the second remover E2 becomes the temperature T1. Therefore, even after the fuel gas is supplied to the fuel cell 14 after the temperature of the second remover E2 becomes lower than the temperature T3, the temperature of the second remover E2 gradually decreases from the temperature T3 to the temperature T1. .. Therefore, as shown in FIG. 3A, a period during which the fuel gas having a low ammonia concentration of the allowable upper limit concentration α or less is supplied to the fuel cell 14 is secured. For example, it is conceivable that the temperature of the second remover E2 is not lower than the temperature T3 but becomes a temperature T1 lower than the temperature T3 before switching to the fourth state. In this case, the temperature of the second remover E2 is the temperature. Since it takes a long time to decrease to T1, the period during which the fuel gas can be supplied to the fuel cell 14 is reduced.

Further, the third state is maintained until a positive determination is made in step S13a. In the third state, the air remaining in the upstream branch path 22, the second remover E2, and the downstream branch path 24 is exhausted to the outside together with the fuel gas. Therefore, in the fourth state to be switched after that, the air remaining in the upstream branch path 22, the second remover E2, and the downstream branch path 24 is suppressed from being supplied to the fuel cell 14 together with the fuel gas.

In this way, in the third state, the air remaining in the upstream branch path 22, the second remover E2, and the downstream branch path 24 before the fourth state is exhausted to the outside to prepare for the fourth state, while preparing for the fourth state. 2 It is in a state of waiting until the temperature of the remover E2 drops below the temperature T3. Therefore, for example, when the temperature of the second remover E2 is lowered after the exhaust of the residual air is completed, or when the temperature of the second remover E2 is lowered to the temperature T1, the exhaust of the residual air is started. The period during which the fuel gas having a low ammonia concentration cannot be supplied to the fuel cell 14 is shortened as compared with the case where the fuel gas has a low ammonia concentration. In other words, a period during which the fuel gas having a low ammonia concentration is supplied to the fuel cell 14 is secured.

If a negative determination is made in step S5, the fourth state is switched to the first state. Specifically, the fourth state is switched to the third state (step S7b), and then the third state is switched to the second state (step S9b). Specifically, from the fourth state, the three-way valve V4 is controlled first, and the fuel gas is switched to the third state in which the fuel gas is exhausted to the outside through the exhaust branch path 33 and the exhaust junction flow path 35, and the third state is switched to the three-way valve. The valve V2 is controlled to switch to a second state in which air is exhausted to the outside via the upstream branch passage 22 and the downstream branch passage 24. For example, if air flows through the upstream branch path 22 and the downstream branch path 24 by controlling the three-way valve V2 before controlling the three-way valve V4 from the fourth state, air may flow into the fuel cell 14 together with the fuel gas. .. In this embodiment, as described above, the three-way valve V4 is first controlled so that the fuel gas is not supplied to the fuel cell 14, and then the three-way valve V2 is controlled, so that air is supplied to the fuel cell 14. Is prevented.

Next, in the second state, the heat exchanger 8 is controlled so that the temperature of the air returns to the original temperature (step S11b). As a result, high-temperature air passes through the second remover E2, and the temperature of the second remover E2 begins to rise. Further, the fuel gas passes through the first remover E1 and the temperature is further lowered.

Next, it is determined whether or not the temperature of the first remover E1 has dropped to less than the temperature T3 (step S13b). The temperature of the first remover E1 is calculated based on the detected value of the temperature sensor S1. In the case of a negative determination, step S13b is executed again. In the case of an affirmative determination, the state is switched to the first state (step S15b), and the switching control ends. As a result, the fuel gas that has passed through the first remover E1 is supplied to the fuel cell 14. In this case as well, for the same reason as described above, the period during which the fuel gas having a low ammonia concentration is supplied to the fuel cell 14 is secured.

FIG. 7A is an example of a time chart showing the temperature changes of the first remover E1 and the second remover E2 due to the switching control from the first state to the fourth state in this embodiment. In FIG. 7A, the time intervals are the same from t to t16. When the switching timing requires switching between the first remover E1 and the second remover E2 (affirmative determination in step S1), the temperature of the second remover E2 begins to decrease at time t2 (step S3). Next, when the current state is the first state (affirmative determination in step S5), the air temperature is returned in the order of the second and third states at time t3 (steps S7a, S9a, S11a). As a result, air having a temperature higher than that of the fuel gas passes through the first remover E1 and the temperature of the first remover E1 begins to rise, and the air remaining in the second remover E2 and the like is combined with the fuel gas. While exhausting, the temperature of the second remover E2 is further lowered by the passage of the fuel gas having a temperature lower than that of air. When the temperature of the second remover E2 becomes lower than the temperature T3 (affirmative determination in step S13a), the state is switched to the fourth state at time t6 (step S15a). As a result, after time t6, the fuel gas having a low ammonia concentration that has passed through the second remover E2 is supplied to the fuel cell 14. Therefore, the time t2 to the time t6 corresponds to the temperature lowering period for lowering the temperature of the second remover E2, and from the time t3 to the time t6, the exhaust gas that has remained in the second remover E2 or the like is exhausted. Corresponds to the period. After the time t6, the temperature of the second remover E2 drops to the temperature T1 due to the fuel gas.

FIG. 7B is an example of a time chart showing the temperature changes of the first remover E1 and the second remover E2 due to the switching control from the first state to the fourth state in the comparative example. In the comparative example, a case will be described in which the temperature of the second remover E2 drops to the temperature T1 in the first state, and then the second, third, and fourth states are switched in this order. When it is determined that switching between the first remover E1 and the second remover E2 is necessary, the temperature of the air begins to decrease at time t2, and the temperature of the second remover E2 begins to decrease, the second remover E2 begins to decrease at time t8. The temperature of E2 drops to the temperature T1. During the period from time t2 to time t8, the fuel gas having a high ammonia concentration that has passed through the first remover E1 continues to be supplied to the fuel cell 14. At time t8, the second and third states are switched in this order, and the air remaining in the upstream branch path 22, the second remover E2, and the downstream branch path 24 is exhausted to the outside together with the fuel gas. This exhaust is completed at time t11. Therefore, since the fourth state is switched at time t11, the fuel gas having a low ammonia concentration that has passed through the second remover E2 after time t11 is supplied to the fuel cell 14. Therefore, the time t2 to the time t8 corresponds to the temperature lowering period for lowering the temperature of the second remover E2, and from the time t8 to the time t11, the exhaust gas that has remained in the second remover E2 or the like is exhausted. Corresponds to the period.

As described above, in the comparative example, the fuel gas having a high ammonia concentration is supplied to the fuel cell 14 for a long period from time t2 to time t8, and the fuel gas having a low ammonia concentration is supplied to the fuel cell 14 after time t11. It will be started. On the other hand, in this embodiment, the fuel gas having a high ammonia concentration is supplied to the fuel cell 14 only for a relatively short period from time t2 to time t3, and the fuel cell 14 of the fuel gas having a low ammonia concentration after time t6. Supply to is started. As described above, in this embodiment, the period during which the fuel gas having a low ammonia concentration is supplied to the fuel cell 14 is secured.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

In the above embodiment, the final supply target of the fuel gas is the fuel cell 14, but the present invention is not limited to this. For example, the supply target may be equipment or device other than a fuel cell that generates electricity using fuel gas, or may be equipment or device that consumes fuel gas to secure power.

In the above embodiment, air is used as the regenerated gas for desorbing ammonia from the first remover E1 or the second remover E2, but the present invention is not limited to this, and for example, the fuel off gas discharged from the fuel cell 14 is used. You may use it.

In the above embodiment, the temperatures of the first remover E1 and the second remover E2 are controlled by the temperatures of the fuel gas and air, but the temperature is not limited thereto. For example, the temperature of the first remover E1 and the second remover E2 may be controlled by using a heater that heats each of the first remover E1 and the second remover E2.

In the above embodiment, step S7a or S7b is executed after the execution of step S3, but step S3 may be executed after the execution of step S7a or 7b. Further, it is not necessary to execute steps S3, S11a, and S11b.

12 Removal system 14 Fuel cell 100 Control unit E1 1st remover E2 2nd remover V1 to V4 Three-way valve

Claims (1)

Impurities in the supplied fuel gas are adsorbed at the first temperature, and the adsorbed impurities are desorbed into the regenerated gas at a second temperature higher than the first temperature, using the first and second removers. It is a fuel gas supply method for supplying the fuel gas having a low concentration of
While the fuel gas passes through the first remover at the first temperature and is supplied to the supply target, the regenerated gas passes through the second remover at the second temperature and other than the supply target. A step of switching from the first state in which the fuel gas is discharged to the second state in which the fuel gas passes through the second remover and is discharged to a state other than the supply target.
A step of switching from the second state to a third state in which the regenerated gas passes through the first remover and is discharged to a state other than the supply target.
The step of lowering the temperature of the second remover and
When the second remover drops to a third temperature higher than the first temperature and lower than the second temperature, the fuel gas passes through the second remover and is supplied from the third state. A fuel gas supply method including a step of switching to the fourth state of being supplied to the target.

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