JP2011040259A - Hydrotreating system - Google Patents

Abstract

A hydrogen treatment system that stops hydrogen treatment in an electrode structure while preventing a combustor from becoming high temperature and suppressing energy loss due to wasteful operation.
When a system stop instruction is issued in STEP 1 during execution of an operation in a hydrogen purification mode in which an electrode structure 20 functions as an ion pump, an operation control means 61 is provided with a reformer 30 in STEP 2 and 3. The supply of raw fuel and reformed air to the heat exchanger 31 is stopped, the timer is started in STEP4, the loop of STEP5 to STEP7 is executed, and the operation in the hydrogen purification mode is continued. When the change rate of the inter-electrode voltage Vcell of the electrode structure 20 becomes equal to or lower than VRth in STEP 6 and the timer times out in STEP 7, the process proceeds to STEP 8, and the operation control means 61 stops the operation in the hydrogen purification mode.
[Selection] Figure 3

Description

  The present invention relates to a hydrogen treatment system for treating hydrogen in reformed gas generated by a reformer.

  Conventionally, a reformer that reforms a raw fuel mainly composed of hydrocarbons to generate a hydrogen-rich reformed gas, and an electrode structure configured by disposing an electrolyte membrane between an anode electrode and a cathode electrode (DMS: Dual Mode Stack) is known, and a hydrogen treatment system is known in which reformed gas is supplied from a reformer to an electrode structure, and hydrogen in the reformed gas is treated by the electrode structure (for example, , See Patent Document 1).

  In the hydrogen treatment system described in Patent Document 1, an operation in a hydrogen purification mode in which the electrode structure functions as an ion pump to purify hydrogen from the reformed gas obtained by the reformer, and the electrode structure is An operation in a power generation mode is performed in which a current is output by a reaction between hydrogen in the reformed gas and an oxidant gas by functioning as a fuel cell.

  During operation in the hydrogen purification mode or power generation mode, hydrogen in the reformed gas is consumed with the purification or power generation processing in the electrode structure, but not all hydrogen in the reformed gas is consumed. In other words, off-gas in which hydrogen that has not been consumed remains is exhausted to the combustor of the reformer.

  Then, the hydrogen in the off-gas burns in the combustor, and the heat of combustion heats the heat exchanger to which the raw fuel and water are supplied to produce a mixed fuel of the raw fuel and steam. The reformed gas is generated by steam reforming.

JP 2009-120421 A

  When the operation in the hydrogen purification mode or the power generation mode is stopped, the supply of the raw fuel to the reformer is stopped, but the reforming process in the reformer is finished immediately even if the supply of the raw fuel is stopped. Therefore, the state in which the reformed gas is supplied to the electrode structure continues for some time.

  As described above, when the operation in the hydrogen purification mode or the power generation mode is stopped while the reformed gas is supplied to the electrode structure, hydrogen is not consumed in the electrode structure, and off-gas having a high hydrogen concentration is burned. The amount of combustion in the combustor is increased by being supplied to the combustor. In this case, when the combustor becomes hot, the combustor itself may be deteriorated or peripheral devices of the combustor may be damaged.

  Thus, it is conceivable to provide a large combustor (such as a large-capacity catalytic combustor) having the ability to cope with an increase in the amount of fuel. In this case, however, the size of the hydrogen treatment system becomes large. There is.

  In order to cope with a small combustor, the supply amount of raw fuel to the reformer is gradually decreased, and then the operation in the hydrogen purification mode or the power generation mode is stopped. It is conceivable to prevent exhausting to the combustor. However, in this case, the time until the reformer is stopped becomes longer, and the time until the operation in the hydrogen purification mode or the operation in the power generation mode is stopped becomes longer. Therefore, there is an inconvenience that energy loss occurs due to useless operation.

  Therefore, the present invention provides a hydrogen treatment system capable of stopping the hydrogen treatment in the electrode structure while preventing the combustor of the reformer from becoming high temperature and suppressing energy loss due to wasteful operation. The purpose is to provide.

  The present invention has been made to achieve the above object, and reforming raw fuel to generate reformed gas, a reformer having a combustor as a heat source for reforming processing, and a gas flow path. An electrode structure having an anode electrode and a cathode electrode arranged with an electrolyte membrane interposed therebetween, an anode off-gas channel connecting the gas channel of the anode electrode and the combustor, the anode electrode, and the anode electrode By supplying the reformed gas to the anode electrode with a predetermined voltage applied between the cathode electrodes, the electrode structure is caused to function as an ion pump, and hydrogen in the reformed gas is transmitted through the electrolyte membrane. The hydrogen purification mode of transferring to the cathode electrode side, supplying the reformed gas to the anode electrode, and supplying the oxidizing gas to the cathode electrode, A hydrogen treatment operation including at least one of an operation in a power generation mode for supplying electric power to an electric load connected between the anode electrode and the cathode electrode by causing the polar structure to function as a fuel cell The present invention relates to an improvement of a hydrogen treatment system provided with operation control means.

  In the first aspect of the present invention, the operation control means stops the supply of raw fuel to the reformer when a predetermined operation stop condition is satisfied during execution of the hydrogen treatment operation. The hydrogen treatment operation is stopped when a predetermined time has elapsed.

  According to the present invention, when the operation stop condition is satisfied during the execution of the hydrogen treatment operation, the operation control unit has stopped supplying a raw fuel to the reformer and a predetermined time has elapsed. Sometimes the hydrogen treatment operation is stopped. In this case, even after the supply of raw fuel to the reformer is stopped, the hydrogen treatment operation continues and hydrogen is consumed in the electrode structure. Therefore, offgas having a high hydrogen concentration is exhausted to the combustor through the anode offgas flow path, and the combustor can be prevented from becoming high temperature due to an increase in the combustion amount. Further, the supply of raw fuel to the reformer is stopped, so that the amount of reformed gas supplied to the electrode structure decreases rapidly, and the hydrogen concentration in the off-gas exhausted to the combustor decreases rapidly. The predetermined time can be set to a short time. Therefore, useless energy loss in the reformer and the electrode structure when the hydrogen treatment operation is stopped, and the equipment connected to the electrode structure can be suppressed.

  Further, in the first aspect, the apparatus includes an interelectrode voltage detection unit that detects a voltage between the anode electrode and the cathode electrode of the electrode structure, and the operation control unit is configured to perform a predetermined operation during the execution of the hydrogen treatment operation. When the operation stop condition is satisfied, after the supply of raw fuel to the reformer is stopped, the detection voltage of the inter-electrode voltage detection means satisfies a predetermined voltage stabilization condition and the predetermined time has elapsed. The hydrogen treatment operation is stopped.

  In the present invention, when the voltage between the anode electrode and the cathode electrode of the electrode structure detected by the interelectrode voltage detection means satisfies the voltage stabilization condition, each component of the reformer is It can be determined that the temperature is within an appropriate temperature range in which performance can be maintained. Therefore, after the supply of raw fuel to the reformer is stopped, the hydrogen treatment operation is stopped when the detection voltage of the interelectrode voltage detection means satisfies the voltage stabilization condition and the predetermined time has elapsed. By doing so, the hydrogen treatment operation is stopped when the reformer including the combustor is in an appropriate state, and it is more reliable that off-gas having a high hydrogen concentration is exhausted to the combustor. Can be prevented.

  Next, a second aspect of the present invention includes combustor temperature detection means for detecting the temperature of the combustor, and the operation control means satisfies a predetermined operation stop condition during execution of the hydrogen treatment operation. In this case, after the supply of the raw fuel to the reformer is stopped, the hydrogen treatment operation is stopped when the temperature detected by the combustor temperature detecting means becomes a predetermined temperature or lower.

  According to the present invention, when the operation stop condition is satisfied during the execution of the hydrogen treatment operation, the operation control means stops the supply of raw fuel to the reformer, and then detects the combustion equipment temperature. When the detected temperature of the means becomes equal to or lower than the predetermined temperature, the hydrogen treatment operation is stopped. In this case, even after the supply of raw fuel to the reformer is stopped, the hydrogen treatment operation continues and hydrogen is consumed in the electrode structure. For this reason, off gas having a high hydrogen concentration is exhausted to the fuel device via the anode off gas flow path, and it is possible to prevent the combustor from reaching a high temperature due to an increase in the combustion amount. Then, the supply of raw fuel to the reformer stops, the supply amount of reformed gas to the electrode structure decreases rapidly, and the hydrogen concentration in the off-gas exhausted to the combustor decreases rapidly. Therefore, the temperature of the combustor falls below the predetermined temperature in a short time. Therefore, useless energy loss in the reformer and the electrode structure when the hydrogen treatment operation is stopped, and the equipment connected to the electrode structure can be suppressed.

  Further, in the second aspect, it further comprises an interelectrode voltage detection means for detecting a voltage between the anode electrode and the cathode electrode of the electrode structure, and the operation control means is configured to perform a predetermined operation during the execution of the hydrogen treatment operation. When the operation stop condition is satisfied, after the supply of raw fuel to the reformer is stopped, the detection voltage of the interelectrode voltage detection means satisfies a predetermined voltage stability requirement, and the detection of the combustor temperature detection means The hydrogen treatment operation is stopped when the temperature falls below the predetermined temperature.

  In the present invention, when the voltage between the anode electrode and the cathode electrode of the electrode structure detected by the interelectrode voltage detection means satisfies the voltage stabilization condition, each component of the reformer is It can be determined that the temperature is within an appropriate temperature range in which performance can be maintained. Therefore, after the supply of raw fuel to the reformer is stopped, the detection voltage of the interelectrode voltage detection means satisfies the voltage stability condition, and the detection temperature of the combustor temperature detection means is less than the predetermined temperature. When the hydrogen treatment operation is stopped, the hydrogen treatment operation is stopped when the reformer including the combustor is in an appropriate state. It is possible to more reliably prevent off-gas having a high concentration from being exhausted.

Explanatory drawing which showed the operation state in the hydrogen purification mode of a hydrogen treatment system. Explanatory drawing which showed the operating state in the electric power generation mode of a hydrogen treatment system. The flowchart by 1st Embodiment of the stop process of a hydrogen treatment system. Explanatory drawing which showed the temperature change of the catalytic combustor at the time of stopping supply of raw fuel and stopping hydrogen consumption in the electrode structure at the same timing. Explanatory drawing which showed the temperature change of the catalytic combustor when the hydrogen consumption in an electrode structure is stopped after the supply of raw fuel is stopped. The flowchart by 2nd Embodiment of the stop process of a hydrogen treatment system.

  Embodiments of the present invention will be described with reference to FIGS. Referring to FIG. 1, a hydrogen treatment system 10 of this embodiment includes a fuel cell and an electrode structure 20 functioning as an ion pump (hereinafter referred to as DMS (Dual Mode Stack) 20), and a raw fuel mainly composed of hydrocarbons. A reformer 30 that reforms a mixed fuel of (city gas, etc.) and steam to generate reformed gas, a blower 50 that supplies air as an oxidant gas to the DMS 20, and hydrogen gas purified by the DMS 20 is dehumidified. In addition, a hydrogen purification processor 55 for further purification and a controller 60 that performs overall control of the hydrogen treatment system 10 are provided. Note that the hydrogen gas purified by the hydrogen purification processor 55 is compressed by a compression unit (not shown) and filled in a hydrogen cylinder of a fuel cell vehicle or the like by a filling unit (not shown).

The reformer 30 mixes steam with hydrocarbons such as methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₆ ), and butane (C ₄ H ₁₀ ) contained in the raw fuel. A heat exchanger (evaporator) 31 for generating a mixed fuel, a catalytic combustor 35 (corresponding to the combustor of the present invention) for applying heat for generating steam to the heat exchanger 31, and steam reforming the mixed fuel A reformer 32 for generating a reformed gas, and a CO converter (shift for converting carbon monoxide (CO) and water vapor in the reformed gas into carbon dioxide (CO ₂ ) and hydrogen (H ₂ ) by a shift reaction. Reactor) 33 and a CO remover (selective oxidation reactor) 34 for adding a small amount of air to the reformed gas and reacting selectively absorbed carbon monoxide with oxygen in the air to convert it into carbon dioxide. It has.

  The heat exchanger 31 is supplied with raw fuel, water, and air for reforming (hereinafter referred to as reformed air), and is heated in the heat exchanger 31, so that the mixed fuel of the raw fuel and water vapor is changed. It is supplied to the reformer 32 in a state mixed with the reformed air.

  The reformer 32 is an autothermal reformer having a palladium (Pd) noble metal catalyst as a reforming catalyst therein, and the mixed fuel generated in the heat exchanger 31 is partially oxidized by reformed air. Thus, a hydrogen-rich reformed gas is generated.

  The catalytic combustor 35 is provided with a temperature sensor 35a (corresponding to the combustor temperature detecting means of the present invention) for detecting the temperature of the catalytic combustor 35. Similarly, the reformer 32, the CO converter 33, and the CO remover 34 are individually provided with temperature sensors 32a, 33a, and 34a that detect these temperatures. Further, an inter-electrode voltage sensor 65 (corresponding to the inter-electrode voltage detection means of the present invention) for detecting the voltage between the anode electrode 22 and the cathode electrode 23 of the DMS 20 is provided.

  The DMS 20 has an electrolyte membrane / electrode structure portion in which a solid polymer electrolyte membrane 21 is sandwiched between an anode electrode 22 and a cathode electrode 23, and constitutes a stack in which the electrolyte membrane / electrode structure portion is alternately laminated with a separator (not shown). ing. In this case, a gas flow path is formed between the electrolyte membrane / electrode structure and the separator.

  The DMS 20 has an anode inlet 24 for supplying the reformed gas to the anode electrode 22, an anode outlet 25 for discharging the used reformed gas (anode offgas) from the anode electrode 22, and an oxidant gas on the cathode electrode 23. A cathode inlet 27 for supplying air and a cathode outlet 26 for discharging used air (cathode off-gas) from the cathode electrode 23 and discharging purified hydrogen from the reformed gas are provided. .

  The anode inlet 24 and the CO remover 34 are connected by a reformed gas channel 40, and the anode outlet 25 and the catalytic combustor 35 are connected by an anode offgas channel 44. A three-way electromagnetic valve 41 is disposed in the reformed gas flow path 40. Connected to the three-way solenoid valve 41 is an anode bypass passage 42 communicating with the anode off-gas passage 44.

  The three-way solenoid valve 41 includes a gas flow state in which the reformed gas passage 40 communicates with the anode inlet 24 and is blocked from the anode bypass passage 42, and the reformed gas passage 40 communicates with the anode bypass passage 42. The gas cutoff state blocked from the anode inlet 24 is switched.

  An electromagnetic valve 43 is provided on the upstream side of the joining point between the anode off-gas channel 44 and the anode bypass channel 42. A cathode inlet channel 52 is connected to the cathode inlet 27. The cathode inlet channel 52 is provided with an electromagnetic valve 51 and a blower 50.

  A cathode offgas passage 45 is connected to the cathode outlet 26, and an electromagnetic valve 48 is provided in the cathode offgas passage 45. Further, the cathode off-gas channel 45 communicates with the cathode purge channel 46 on the upstream side of the electromagnetic valve 48, and the cathode purge channel 46 communicates with the anode off-gas channel 44 via the electromagnetic valve 47. A hydrogen gas flow channel 53 is connected to the cathode off-gas flow channel 45, and a downstream side of the hydrogen gas flow channel 53 is connected to a hydrogen purification processor 55 via an electromagnetic valve 54.

  The controller 60 is an electronic unit configured by a CPU (Central Processing Unit), a memory, and the like. The temperature detection signals of the temperature sensors 32a, 33a, 34a, and 35a and the voltage detection signal of the interelectrode voltage sensor 65 are the controller 60. Is input. In addition, according to the control signal output from the controller 60, the three-way solenoid valve 41, the solenoid valves 43, 47, 48, 51, 54 and the blower 50 are actuated and the raw fuel and reformed air are supplied / Stop is controlled.

  Further, the controller 60 functions as the operation control means 61 by causing the CPU to execute a control program for the hydrogen treatment system 10. The motion control means 61 executes the hydrogen treatment operation of the present invention by switching between the operation in the hydrogen purification mode in which the DMS 20 functions as an ion pump and the operation in the power generation mode in which the DMS 20 functions as a fuel cell.

  Hereinafter, the operation of the hydrogen treatment system 10 in the hydrogen purification mode and the power generation mode will be described.

  First, the operation of the hydrogen treatment system when operating in the hydrogen purification mode will be described with reference to FIG. The operation control means 61 closes the solenoid valves 47, 48, 51 and opens the solenoid valves 43, 54. Further, the operation control means 61 changes the three-way electromagnetic valve 41 from the reforming device 30 to the anode electrode 22 with the reformed gas flow path 40 in communication with the anode inlet 24 and shut off from the anode bypass flow path 42. To supply reformed gas.

Then, the operation control means 61 applies a predetermined voltage between the anode electrode 22 and the cathode electrode 23 of the DMS 20 with the anode electrode 22 as a high potential side. Thereby, in the anode electrode 22, reaction of the following formula | equation (1) occurs and hydrogen ion (H ^<+> ) generate | occur | produces.

_{^{H 2 → 2H + + 2e -}} ····· (1)
Then, hydrogen ions permeate the solid polymer electrolyte membrane 21 and move to the cathode electrode 23, where the reaction of the following formula (2) is induced and the pressure is increased.

2H ⁺ + 2e ⁻ → H ₂ (2)
In this way, the hydrogen ions move from the anode electrode 22 to the cathode electrode 23, whereby the high-purity hydrogen gas is purified from the reformed gas. This hydrogen gas is sent to the hydrogen purification processor 55 through the hydrogen gas flow path 53, and is subjected to dehumidification and purification by the hydrogen purification processor 55.

  In addition, the reformed gas (including unextracted hydrogen) after the extraction of hydrogen ions at the anode electrode 22 is supplied as an anode off-gas from the anode outlet 25 to the catalytic combustor 35 via the anode off-gas passage 44. Sent out. Hydrogen in the anode off gas burns in the catalytic combustor 35, and the combustion heat is given to the heat exchanger 31.

  Next, the operation of the hydrogen treatment system 10 when operating in the power generation mode will be described with reference to FIG. In the power generation mode, an electrical load 70 connected between the anode electrode 22 and the cathode electrode 23 of the DMS 20 is used.

  The operation control means 61 closes the solenoid valves 47, 54 and opens the solenoid valves 43, 48, 51. Further, the operation control means 61 changes the three-way solenoid valve 41 from the reformer 30 to the anode electrode with the reformed gas channel 40 in communication with the anode inlet 24 and the gas supply state shut off from the anode bypass channel 42. The reformed gas is supplied to 22.

In addition, the operation control means 61 operates the blower 50 to supply air (oxidant gas) to the cathode inlet 27 via the cathode inlet channel 52. Thus, the DMS 20, the anode electrode 22, a reaction occurs in the following equation (3), hydrogen gas _{(H 2)} electron e ^- the hydrogen ions ^{(H +)} to release the.

H ₂ → 2H ⁺ + 2e ⁻ (3)
Hydrogen ions permeate through the solid polymer electrolyte membrane 21, and at the cathode electrode 23, the oxygen gas (O ₂ ) in the air supplied from the cathode inlet 27 and the electrons e ⁻ supplied to the cathode electrode 23. The reaction of the following formula (4) occurs to generate water.

1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (4)
Then, as shown in the above formulas (3) and (4), current flows from the anode electrode 22 to the cathode electrode 23 via the electric load 70, and power is supplied from the DMS 20 to the electric load 70.

  In addition, the reformed gas (including unextracted hydrogen) after the extraction of hydrogen ions at the anode electrode 22 is supplied as an anode off-gas from the anode outlet 25 to the catalytic combustor 35 via the anode off-gas passage 44. Sent out. Hydrogen in the anode off gas is burned in the catalytic combustor 35 and the combustion heat is given to the heat exchanger 31.

  Next, according to the flowchart shown in FIG. 3, a first embodiment of the process by the operation control means 61 when an instruction to stop the hydrogen treatment system 10 is given during the execution of the operation in the hydrogen purification mode.

[First Embodiment]
If an instruction to stop the system is given in STEP1 during operation in the hydrogen purification mode, the process proceeds to STEP2. And the operation control means 61 stops supply of the raw fuel and the reformed air to the heat exchanger 31 in STEPs 2 and 3.

  In the next STEP 4, the operation control means 61 starts a timer, and repeatedly executes the subsequent loop of STEP 5 to STEP 7 until the timer expires in STEP 7. In the loop of STEP5 to STEP7, the operation control means 61 continues the operation in the hydrogen purification mode in STEP5 (a state in which a predetermined voltage is applied between the anode electrode 22 and the cathode electrode 23 of the DMS 20), and the electrode in STEP6. The change rate of the voltage Vcell (the change width of the voltage Vcell per predetermined time) between the anode electrode 22 and the cathode electrode 23 of the DMS 20 detected by the inter-voltage sensor 65 is equal to or less than a predetermined value VRth (under the predetermined voltage stabilization condition of the present invention). Or the like).

  Here, the predetermined value VRth is that hydrogen purification in the DMS 20 is stably performed. As a precondition, the temperature of the catalytic combustor 35 and the temperature of the reformer 32 fall within a temperature range in which specified performance can be maintained. It is set to a value that can be determined to be.

  Note that the predetermined voltage stabilization condition of the present invention is set such that the voltage Vcell between the anode electrode 22 and the cathode electrode 23 of the DMS 20 is maintained within a preset voltage range within a preset predetermined time. May be.

  In STEP 6, when the change rate of the voltage Vcell between the anode electrode 22 and the cathode electrode 23 of the DMS 20 is equal to or less than VRth, the process proceeds to STEP 7, and when this change rate is higher than VRth, the process branches to STEP5.

  In STEP 7, the operation control means 61 determines whether or not the timer has timed up. If the timer has timed out, the operation proceeds to STEP 8, and if the timer has not timed out, branches to STEP 5. Here, the set time until the timer expires (corresponding to the predetermined time of the present invention) is supplied to the anode electrode of the DMS 20 from the time when the supply of the raw fuel and reformed air to the heat exchanger 31 is stopped. Even if the amount of reformed gas is reduced and the operation in the hydrogen purification mode is stopped, the temperature of the catalytic combustor 35 is kept at the threshold value Tth (the catalytic combustor 35 and peripheral devices are prevented from deteriorating). It is set on the assumption of the time required for the temperature to be equal to or lower.

  In STEP 8, the operation control means 61 stops applying the predetermined voltage between the anode electrode 22 and the cathode electrode 23 of the DMS 20 to stop the operation in the hydrogen purification mode, and proceeds to STEP 9 to stop the hydrogen treatment system 10. Exit.

  Next, with reference to FIGS. 4 and 5, the effect of the stop process of the hydrogen treatment system 10 shown in FIG. 3 will be described. 4 and 5, the horizontal axis is set to time (t), and the vertical axis is the temperature (Tcat) of the catalytic combustor 35, the hydrogen consumption (hydrogen purification amount) in the DMS 20, and the heat exchanger 31. It shows the temperature change of the catalytic combustor 35, the stop timing of the raw fuel to the heat exchanger 31, and the stop timing of the operation in the hydrogen purification mode by setting the supply amount of the raw fuel.

First, in FIG. 4, the stop processing of the shutdown in the hydrogen purification mode is the same as the timing of stopping the supply of raw fuel and reformed air to the heat exchanger 31 and the shutdown timing of the DMS 20 in the hydrogen purification mode. The case where it went to is shown. In this case, the supply of raw fuel and reformed air to the heat exchanger 31 is stopped at t ₁₀ , and the operation of the DMS 20 in the hydrogen purification mode is stopped, and the hydrogen consumption in the DMS 20 becomes zero. Yes.

Here, even if the supply of the raw fuel and the reformed air to the heat exchanger 31 is stopped at t ₁₀ , a certain delay time occurs until the reforming process in the reformer 30 is stopped. For this reason, when the hydrogen consumption in the DMS becomes zero at t ₁₀ , the hydrogen-rich reformed gas supplied to the anode electrode 22 of the DMS 20 passes through the anode off-gas channel 44 without being subjected to hydrogen purification. And exhausted to the catalytic combustor 35.

  Therefore, the amount of combustion in the catalytic combustor 35 increases rapidly, the temperature Tcat of the catalytic combustor 35 rapidly increases, and the temperature Tcat of the catalytic combustor 35 exceeds the upper limit threshold Tth. In this case, there is a possibility that the catalytic combustor 35 and the peripheral devices of the catalytic combustor 35 may deteriorate.

On the other hand, in FIG. 5, the process of stopping the operation in the hydrogen purification mode is performed by the process of the flowchart shown in FIG. 3 rather than the timing of stopping the supply of the raw fuel and reformed air to the heat exchanger 31. This shows a case where the operation stop timing in the hydrogen purification mode is delayed. In this case, the supply of the raw fuel to the heat exchanger 31 is stopped at t ₂₀ , but the operation of the DMS 20 in the hydrogen purification mode is continued by reducing the amount of hydrogen purification. The operation of the DMS 20 in the hydrogen purification mode may be continued without decreasing the amount of hydrogen purification.

At t ₂₁ (when the conditions of STEP 6 and STEP 7 in FIG. 3 are both satisfied), the operation of the DMS 20 in the hydrogen mode is stopped, and the hydrogen consumption in the DMS 20 is zero. As described above, during the period from t ₂₀ to t ₂₁ , the operation in the hydrogen purification mode is continued, and the hydrogen in the reformed gas supplied to the anode electrode 22 of the DMS 20 is consumed by the purification process.

  Therefore, the hydrogen concentration in the anode off-gas exhausted to the catalytic combustor 35 via the anode off-gas flow rate 44 is reduced, and an increase in the combustion amount in the catalytic combustor 35 is suppressed, so that the temperature of the catalytic combustor 35 is increased. Tcat is maintained below the threshold Tth. As a result, the temperature Tcat of the catalytic combustor 35 becomes a high temperature exceeding the threshold value Tth, and it is possible to prevent the catalytic combustor 35 and the peripheral devices of the catalytic combustor 35 from being deteriorated.

  Next, according to the flowchart shown in FIG. 6, a second embodiment of the processing by the operation control means 61 when an instruction to stop the hydrogen processing system 10 is given during the execution of the operation in the hydrogen purification mode.

[Second Embodiment]
The processing of STEP 20 to STEP 22 in FIG. 6 is the same as the processing of STEP 1 to STEP 3 in FIG. 3 described above. When the system stop instruction is given in STEP 20, the process proceeds to STEP 21. The supply of raw fuel and reformed air to the exchanger 31 is stopped.

  Then, the operation control means 61 goes through the next loop of STEP23 to STEP25 until the temperature Tcat of the catalytic combustor 35 detected by the temperature sensor 35a is equal to or lower than Tth (corresponding to the predetermined temperature of the present invention) in STEP25. , Repeat.

  In the loop of STEP23 to STEP25, the operation control means 61 continues the operation in the hydrogen purification mode in STEP23 (a state where a predetermined voltage is applied between the anode electrode 22 and the cathode electrode 23 of the DMS 20), and the electrode in STEP24. It is determined whether the change rate of the voltage Vcell between the anode electrode 22 and the cathode electrode 23 of the DMS 20 detected by the inter-voltage sensor 65 is equal to or less than the above-described VRth (corresponding to the predetermined voltage stabilization condition of the present invention). To do.

  In STEP 24, when the change rate of the voltage Vcell between the anode electrode 22 and the cathode electrode 23 of the DMS 20 is equal to or lower than VRth, the process proceeds to STEP 25, and when this change rate is higher than VRth, the process branches to STEP 23.

  In STEP 25, the operation control means 61 determines whether the temperature Tcat of the catalytic combustor 35 is equal to or lower than Tth. When the temperature Tcat of the combustion catalyst 35 is equal to or lower than Tth, the process proceeds to STEP26, and when the temperature Tcat of the catalyst combustor 35 exceeds Tth, the process branches to STEP23. Here, Tth is set to an upper limit temperature for suppressing deterioration of the catalytic combustor 35 and deterioration of peripheral devices of the catalytic combustor 35.

  In this manner, by continuing the operation in the hydrogen purification mode until the temperature Tcat of the catalytic combustor 35 becomes equal to or lower than Tth in STEP25, the reformer 30 to the DMS20 are similar to the first embodiment described above. Hydrogen in the reformed gas supplied to the anode electrode 22 is consumed. Therefore, the hydrogen concentration in the anode off gas exhausted from the anode electrode 22 to the catalytic combustor 35 via the anode off gas flow path 44 is lowered. As a result, the anode off-gas having a high hydrogen concentration is exhausted to the catalytic combustor 35, the amount of combustion in the catalytic combustor 35 increases rapidly, and the catalytic combustor 35 itself deteriorates due to the temperature rise of the catalytic combustor 35 or catalytic combustion. Deterioration of peripheral devices of the device 35 can be suppressed.

  In the flowcharts shown in FIGS. 4 and 6, the process in the case of stopping the operation in the hydrogen purification mode is shown. However, the operation of the hydrogen treatment system 10 is also stopped during the operation in the power generation mode. The present invention can be applied by the same processing. In this case, the operation control means 61 continues the operation in the power generation mode at STEP 5 in FIG. 3 and STEP 23 in FIG. 6, and connects the DMS 20 and the electric load 70 at STEP 8 in FIG. 3 and STEP 26 in FIG. It is only necessary to shut off and stop the operation in the power generation mode.

  Further, in the present embodiment, in STEP 6 in FIG. 3 and STEP 24 in FIG. 6, the voltage Vcell between the anode electrode 22 and the cathode electrode 23 of the DMS 20 is stable. , And the operation in the power generation mode) is set as a condition for stopping, but the effect of the present invention can be obtained even when this condition is not set.

  Further, in the present embodiment, the hydrogen treatment system that performs the operation in the hydrogen purification mode and the operation in the power generation mode is shown for the electrode structure (DMS20), but only the operation in the hydrogen purification mode or in the power generation mode is shown. The present invention can also be applied to a hydrogen treatment system that operates only.

  In this embodiment, the catalytic combustor 35 is shown as the combustor of the present invention, but a burner may be used.

  DESCRIPTION OF SYMBOLS 10 ... Hydrogen treatment system, 20 ... Electrode structure (DMS: Dual Mode Stack), 21 ... Solid polymer electrolyte membrane, 22 ... Anode electrode, 23 ... Cathode electrode, 30 ... Reformer, 31 ... Heat exchanger, 35 ... Catalyst combustor, 35a ... (Catalyst combustor) temperature sensor, 41 ... Three-way solenoid valve, 60 ... Controller, 61 ... Operation control means, 65 ... Interelectrode voltage sensor.

Claims (4)

A reformer having a combustor as a heat source for reforming treatment while reforming raw fuel to generate reformed gas,
An electrode structure comprising an anode electrode and a cathode electrode each having a gas flow path and an electrolyte membrane interposed therebetween;
An anode off-gas channel connecting the gas channel of the anode electrode and the combustor;
By supplying the reformed gas to the anode electrode with a predetermined voltage applied between the anode electrode and the cathode electrode, the electrode structure functions as an ion pump, and hydrogen in the reformed gas The electrode structure by operating in a hydrogen purification mode in which the electrolyte is permeated through the electrolyte membrane and transferred to the cathode electrode side, supplying the reformed gas to the anode electrode and supplying an oxidant gas to the cathode electrode Operation control for performing a hydrogen treatment operation including at least one of an operation in a power generation mode in which a body functions as a fuel cell and supplies power to an electric load connected between the anode electrode and the cathode electrode A hydrogen treatment system comprising:
When the predetermined operation stop condition is satisfied during the execution of the hydrogen treatment operation, the operation control means stops the supply of raw fuel to the reformer and then performs the hydrogen treatment operation when a predetermined time has elapsed. The hydrogen treatment system characterized by stopping. The hydrogen treatment system according to claim 1,
An inter-electrode voltage detection means for detecting a voltage between the anode electrode and the cathode electrode of the electrode structure;
When the predetermined operation stop condition is satisfied during execution of the hydrogen treatment operation, the operation control means stops the supply of raw fuel to the reformer, and then the detection voltage of the interelectrode voltage detection means is predetermined. The hydrogen treatment system is characterized in that the hydrogen treatment operation is stopped when the predetermined voltage stability condition is satisfied and the predetermined time has elapsed. A reformer having a combustor as a heat source for reforming treatment while reforming raw fuel to generate reformed gas,
An electrode structure comprising an anode electrode and a cathode electrode each having a gas flow path and an electrolyte membrane interposed therebetween;
An anode off-gas channel connecting the gas channel of the anode electrode and the combustor;
By supplying the reformed gas to the anode electrode with a predetermined voltage applied between the anode electrode and the cathode electrode, the electrode structure functions as an ion pump, and hydrogen in the reformed gas The electrode structure by operating in a hydrogen purification mode in which the electrolyte is permeated through the electrolyte membrane and transferred to the cathode electrode side, supplying the reformed gas to the anode electrode and supplying an oxidant gas to the cathode electrode Operation control for performing a hydrogen treatment operation including at least one of an operation in a power generation mode in which a body functions as a fuel cell and supplies power to an electric load connected between the anode electrode and the cathode electrode A hydrogen treatment system comprising:
Combustor temperature detection means for detecting the temperature of the combustor,
When the predetermined operation stop condition is satisfied during execution of the hydrogen treatment operation, the operation control means stops the supply of raw fuel to the reformer, and then the temperature detected by the combustor temperature detection means is predetermined. The hydrogen treatment system is characterized in that the hydrogen treatment operation is stopped when the temperature falls below the temperature. The hydrogen treatment system according to claim 3,
An inter-electrode voltage detection means for detecting a voltage between the anode electrode and the cathode electrode of the electrode structure;
When the predetermined operation stop condition is satisfied during execution of the hydrogen treatment operation, the operation control means stops the supply of raw fuel to the reformer, and then the detection voltage of the interelectrode voltage detection means is predetermined. The hydrogen treatment operation is stopped when the voltage stability requirement is satisfied and the detected temperature of the combustor temperature detecting means becomes equal to or lower than the predetermined temperature.

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