JP2008266118A - Reformer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reformer system having an advantage of suppressing an excessive increase of pressure inside a reformer. <P>SOLUTION: The reformer system has the reformer 2 having a reforming part 34 which generates reformed gas containing hydrogen by means of reacting a gaseous raw material for reforming with water, an inlet-side valve 25a which supplies the gaseous raw material for reforming to the reforming part 34 of the reformer 2 and an outlet-side valve 25h which discharges the reformed gas containing hydrogen. A controller 500 carries out a reforming operation-shutdown procedure in which the reformer 2 is operated to generate the reformed gas containing hydrogen and the reforming operation of the reformer 2 is subsequently shut down. In the shutdown procedure, the controller carries out a closing procedure in which both of the inlet-side valve 25a and the outlet-side valve 25h are closed and then carries out an opening/closing procedure in which it keeps the inlet-side valve 25a being closed, opens the outlet-side valve 25h when the pressure inside the reformer 2 increases to a prescribed pressure and thereafter closes the outlet-side valve 25h. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reformer system that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material.

  In Patent Document 1, in a fuel cell system including a reformer that generates a hydrogen-rich reformed gas from a reforming raw material and a fuel cell, when stopping the operation of the fuel cell system, an outlet side valve and an inlet port are disclosed. A fuel cell system is disclosed in which hydrogen-rich reformed gas remaining in the reformer is left inside the reformer by closing both side valves.

In Patent Document 2, the supply of the raw material gas to the reforming unit and the supply of water are stopped when the system is stopped, and the inlet side valve is opened when the reforming unit and the CO conversion unit are below a predetermined temperature. A hydrogen production system is disclosed in which a raw material gas is supplied to a reforming section and a CO conversion section to enclose the reformed gas.
JP 2005-71934 A JP 2004-307236 A

  However, according to Patent Documents 1 and 2 described above, after the operation of the reformer is stopped, moisture remaining inside is excessively vaporized due to the residual heat of the reformer, and the reformer is converted into steam by steaming. There was a possibility that the internal pressure of would rise excessively.

  The present invention has been made in view of the above circumstances, and provides a reformer system that can suppress an excessive increase in internal pressure of the reformer and that does not require excessive pressure resistance of the reformer. Is an issue.

(1) A reformer system according to aspect 1 includes a reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture. An inlet valve that is arranged upstream of the reformer and supplies the reforming raw material to the reformer of the reformer, and reformed gas generated by the reformer arranged downstream of the reformer is reformed. In a reformer system comprising an outlet valve that discharges from the apparatus, and a controller that controls the inlet valve and the outlet valve,
After the reformer is operated to generate reformed gas, the control unit closes both the inlet side valve and the outlet side valve when performing the reforming operation stop operation to stop the reforming operation of the reformer. An opening / closing operation of opening the outlet side valve when the inside of the reformer rises to a predetermined pressure and then closing the outlet side valve while maintaining the closed state of the inlet side valve. It is characterized by performing.

  The control unit operates the reformer and generates a reformed gas containing hydrogen. Thereafter, the reforming operation of the reformer is stopped. That is, the supply of the reforming raw material and moisture to the reformer is stopped. Then, when stopping the reforming operation, when the reforming section has residual heat and is still in a high temperature state, the control section performs a closing operation for closing both the inlet side valve and the outlet side valve. As a result, the entire reformed gas containing hydrogen produced in the reformer is prevented from being discharged outside the reformer. That is, the reformed gas containing hydrogen can be actively left inside the reformer. Thereby, the oxidative deterioration of the catalyst carried on the reformer is suppressed, and the durability of the catalyst is improved.

  Here, even if the reforming operation is stopped, the liquid phase water remaining in the reformer is vaporized by the residual heat of the reforming unit, so that the pressure inside the reformer increases. When the inside of the reformer rises to a predetermined pressure, the control unit performs an opening / closing operation of opening the outlet side valve while maintaining the state where the inlet side valve is closed, and then closing the outlet side valve. As a result, since the high pressure inside the reformer is released, the pressure inside the reformer is prevented from rising excessively. Therefore, the pressure-resistant structure of the reformer need not be excessive.

  By the way, when the reforming operation is stopped, cooling of the reformer in a high temperature state gradually proceeds. In this case, once generated water vapor is condensed and becomes liquid phase water, there is a possibility that excessive negative pressure may occur inside the reformer. In this case, along with excessive negative pressure, there is a possibility that excessive outside air containing oxygen may enter the interior of the reformer, and the constituent materials inside the reformer (for example, structural materials such as stainless steel, catalysts) There is a risk of oxidative degradation. For example, the catalyst (supported on the carrier) built in the reformer may be oxidized and deteriorated due to the influence of oxygen contained in the outside air. In order to suppress this, it is preferable to employ an expensive special valve having a high pressure-resistant sealing force with a strong closing force for both the inlet side valve and the outlet side valve. However, such a valve is very expensive and is not preferable from the viewpoint of reducing the cost of the reformer system.

  According to aspect 1, if the reforming operation of the reformer is stopped, the reformed gas containing hydrogen can be actively left in the reformer, so that the reformer is cooled. Even if water vapor is condensed, excessive negative pressure in the reformer is suppressed. Therefore, excessive entry of outside air containing oxygen into the reformer is suppressed. Moreover, even if outside air containing air enters the interior of the reformer due to excessive negative pressure, oxygen remaining in the reformer reacts with oxygen in the air, so that oxygen in the air is consumed, The presence of air as oxygen inside the reformer is suppressed. Furthermore, negative pressure is suppressed by nitrogen gas or the like that occupies most of the air (other than consumed oxygen). In this sense, the oxidation deterioration of the catalyst supported on the reformer is suppressed, and the durability of the catalyst is improved. Therefore, for both the inlet side valve and the outlet side valve, use a general valve with a normal sealing force and a low price as well as a special valve with a high pressure-resistant sealing force with a strong closing force. Therefore, the cost of the reformer system can be reduced.

(2) According to the reformer system according to aspect 2, in the above aspect, the control unit closes the inlet side valve while opening the outlet side valve in the closing operation, and after the first predetermined time has elapsed, The side valve is closed. When the reforming operation is stopped, the reforming section is still in a high temperature state due to residual heat. For this reason, the reforming reaction may proceed due to the reforming raw material and moisture remaining inside the reforming section, and hydrogen may be generated. In this case, the gas volume increases. For example, if the reforming raw material contains CH ₄ , it was 2 mol before the reaction due to CH ₄ + H ₂ O → 3H ₂ + CO, but it becomes 4 mol after the reaction, and the gas volume increases. Therefore, according to this aspect, in the closing operation, the inlet side valve is closed while opening the outlet side valve, and after the first predetermined time has elapsed, the outlet side valve is closed while closing the inlet side valve. That is, the closing of the outlet side valve is delayed in time from the closing of the inlet side valve. As a result, it is possible to leave as much as possible the inside of the reformer while discharging the reformed gas containing hydrogen having reducibility. Thereby, it is possible to cope with an increase in gas volume while suppressing oxidation deterioration of the catalyst inside the reformer. Although the first predetermined time is different depending on the type of the reformer, the outlet side valve, etc., the range of 0.3 to 20 seconds, the range of 0.5 to 10 seconds, and the range of 1 to 5 seconds are exemplified. Is done. As described above, as much reformed gas containing hydrogen as possible can be left inside the reformer, so that oxidative deterioration of the catalyst and the like carried on the reformer is suppressed.

  (3) According to the reformer system according to aspect 3, in the above-described aspect, in the reforming operation stop operation, the control unit opens the inlet side valve after the opening / closing operation so that the gaseous reforming is performed. It is characterized in that excessive negative pressure inside the reformer is suppressed by introducing the raw material into the reforming section. As the reforming operation is stopped, the temperature of the reformer gradually decreases. Therefore, since the water vapor present in the reformer is gradually condensed and liquefied to generate water, the inside of the reforming section tends to be negative pressure. Therefore, if the gaseous reforming raw material is positively charged into the reforming section in the reforming operation stop operation, excessive negative pressure inside the reforming section is suppressed. Therefore, the outside air is prevented from entering the reformer. Therefore, as for both the inlet side valve and the outlet side valve, it is possible to use a general valve having a normal sealing force and a low price, as well as an expensive special valve having a high pressure resistance sealing force. Therefore, it can contribute to the cost reduction of the reformer system. According to this aspect, the introduced gaseous reforming raw material may generate hydrogen by a reforming reaction or may not generate hydrogen.

  (4) According to the reformer system according to aspect 4, in the above aspect, in the reforming operation stop operation, when the temperature of the reforming unit is equal to or higher than the reforming reaction temperature after the opening / closing operation. The inlet side valve is opened, and gaseous reforming raw material is charged into the reforming section, whereby hydrogen is generated by the reforming reaction in the reforming section. Since hydrogen has reducibility, it is advantageous for suppressing oxidative deterioration of the catalyst supported on the reformer. Furthermore, since hydrogenous gas is actively generated by introducing a gaseous reforming raw material into the reforming section, excessive negative pressure inside the reformer is suppressed. Therefore, for both the inlet side valve and the outlet side valve, it is not necessary to use an expensive special valve with a high pressure-resistant sealing force with a strong closing force, and use a general valve with a normal sealing force and a low price. be able to. Therefore, it can contribute to the cost reduction of the reformer system.

(5) According to the reformer system according to aspect 5, a reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture. An inlet side valve disposed upstream of the reformer and supplying the reforming raw material to the reformer of the reformer, and a reformed gas generated downstream of the reformer and generated by the reformer. In the reformer system comprising an outlet side valve that discharges from the reformer, and a controller that controls the inlet side valve and the outlet side valve,
In addition to the reforming unit, the reforming device is provided in a heating unit for heating the reforming unit, an evaporation unit for generating water vapor to be supplied to the reforming unit, and provided in the reforming unit so that heat can be exchanged with the evaporation unit And a CO reduction part containing a catalyst for reducing the CO component contained in the reformed gas,
After performing the reforming operation stop operation for stopping the reforming operation of the reformer after the reformer is operated to generate the reformed gas, the control unit The heating is continued for a second predetermined time to suppress the temperature drop of the evaporation part, the temperature reduction rate of the CO reduction part is slowed down, and the catalyst of the CO reduction part is reduced with hydrogen remaining in the CO reduction part. To do.

  According to this aspect, in performing the reforming operation stop operation for stopping the reforming operation of the reformer, the control unit heats the reforming unit by the heating unit of the reformer for a second predetermined time (for example, 2 (Not limited to ~ 60 minutes, 5-30 minutes). According to this aspect, the temperature drop of the evaporation part is suppressed (including a form in which the evaporation part is heated), and the temperature of the evaporation part is maintained as much as possible. As a result, the temperature decrease rate of the CO reduction unit is relaxed, and the CO reduction unit is well maintained at the regeneration temperature of the catalyst of the CO reduction unit. At this time, since hydrogen remains in the CO reduction part, the catalyst supported on the CO reduction part is reduced with hydrogen. Thereby, the oxidative deterioration of the catalyst is suppressed, and the durability of the catalyst is improved. Examples of the CO reduction unit include a CO oxidation removal unit that oxidizes and removes CO contained in the reformed gas with oxygen.

(6) A reformer system according to aspect 6 includes a reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture.
An inlet side valve disposed upstream of the reformer and supplying the reforming raw material to the reformer of the reformer, and a reformed gas generated by the reformer disposed downstream of the reformer In a reformer system comprising an outlet valve that discharges from a reformer, and a controller that controls the inlet valve and the outlet valve,
In addition to the reforming unit, the reforming device is provided in a heating unit for heating the reforming unit, an evaporation unit for generating water vapor to be supplied to the reforming unit, and provided in the reforming unit so that heat can be exchanged with the evaporation unit And a CO reduction section containing a catalyst for reducing the CO component contained in the reformed gas. After the reformer is operated to generate the reformed gas, the reformer is operated for reforming. In carrying out the stop operation of the reforming operation to be stopped, the control unit continues the reforming operation of the reforming device for a third predetermined time after stopping the power generation operation of the fuel cell, and suppresses the temperature drop of the evaporation unit while reducing the temperature of the CO reduction unit. The temperature reduction rate is reduced, and the catalyst of the CO reduction unit is subjected to reduction treatment in a state where hydrogen remains in the CO reduction unit.

  According to this aspect, in performing the reforming operation stop operation for stopping the reforming operation of the reformer, the control unit performs the reforming operation of the reformer for a third predetermined time (for example, 2 to 60 minutes, 5 Continue for 30 minutes (but not limited to this). Thereby, the temperature drop of the evaporation part is suppressed (including a form in which the evaporation part is heated), and the temperature of the evaporation part is kept as high as possible. As a result, the temperature decrease rate of the CO reduction unit is relaxed, and the CO reduction unit is well maintained at the regeneration temperature of the catalyst of the CO reduction unit. At this time, since hydrogen remains in the CO reduction section, the catalyst carried on the CO reduction section is reduced. Thereby, the oxidative deterioration of the catalyst is suppressed, and the durability of the catalyst is improved.

(7) A reformer system according to aspect 7 includes a reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture.
An inlet valve that is arranged upstream of the reformer and supplies the reforming raw material to the reformer of the reformer, and a reformed gas generated by the reformer arranged downstream of the reformer is modified. In a reformer system comprising an outlet side valve that discharges from a quality control device, and a controller that controls the inlet side valve and the outlet side valve,
In addition to the reforming unit, the reforming device is provided in a heating unit for heating the reforming unit, an evaporation unit for generating water vapor to be supplied to the reforming unit, and provided in the reforming unit so that heat can be exchanged with the evaporation unit And a CO reduction section containing a catalyst for reducing the CO component contained in the reformed gas. After the reformer is operated to generate the reformed gas, the reformer is operated for reforming. In performing the reforming operation stop operation to be stopped, the control unit performs the power generation operation of the fuel cell for the fourth predetermined time in the low output region while maintaining the reforming operation of the reformer, and the CO reduction unit The temperature reduction rate is relaxed, and the catalyst of the CO reduction unit is subjected to reduction treatment in a state where hydrogen remains in the CO reduction unit.

  According to this aspect, in performing the reforming operation stop operation for stopping the reforming operation of the reformer, the control unit performs the reforming operation of the reformer and performs the power generation operation of the fuel cell in the low output region. Continue for a fourth predetermined time (for example, 1 to 60 minutes, 5 to 30 minutes). At this time, since the reforming operation of the reforming apparatus is maintained, the temperature drop of the evaporation unit is suppressed (including a mode in which the evaporation unit is heated), and the temperature of the evaporation unit is maintained as high as possible. For this reason, the temperature lowering rate of the CO reduction part is relaxed, and the CO reduction part is well maintained at the regeneration temperature of the catalyst of the CO reduction part. At this time, since hydrogen remains in the CO reduction section, the catalyst carried on the CO reduction section is reduced. Thereby, the oxidative deterioration of the catalyst is suppressed, and the durability of the catalyst is improved. When operating the fuel cell in the low power region, the reformed gas is supplied as the anode gas to the fuel electrode of the fuel cell, which can contribute to the removal of liquid phase water inside the fuel cell. This contributes to suppression of flooding during power generation operation.

  (8) According to the reformer system according to aspect 8, in each aspect described above, the control unit causes the cooling gas to flow into the heating unit that heats the reforming unit in the reforming operation stop operation. To do. The reformer is actively cooled by a cooling gas (for example, air). This suppresses slow cooling of the reformer. This suppresses the reformer from being held at a high temperature for a long time. Accordingly, it is possible to suppress deterioration of the constituent material of the reformer. For example, when alloy steel such as stainless steel is adopted as the constituent material of the reformer, it is suppressed to be held in a temperature region near 475 ° C. (brittle temperature) for a long time. Therefore, it is advantageous for suppressing high temperature deterioration such as 475 ° C. embrittlement.

  According to the reformer system of the present invention, when stopping the reforming operation of the reformer, the closing operation for closing both the inlet side valve and the outlet side valve and the state where the inlet side valve is closed are maintained. However, when the inside of the reformer rises to a predetermined pressure, the outlet side valve is opened, and then the opening / closing operation for closing the outlet side valve is performed. As a result, after the operation of the reformer is stopped, it is advantageous to suppress an excessive increase in the internal pressure of the reformer. For this reason, the pressure resistance of the reformer need not be excessive, and the reformer can be reduced in cost.

  Hereinafter, embodiments of the present invention will be described based on respective examples.

  Example 1 will be specifically described with reference to FIGS. 1 and 2. The reformer according to the present embodiment is applied to a fuel cell system. As shown in FIG. 1, a fuel cell 1 includes a membrane electrode assembly 13 in which a solid polymer membrane 10 formed of a polymer material having proton conductivity is sandwiched between a fuel electrode 11 and an oxidant electrode 12 in the thickness direction. Are assembled. Examples of the material of the solid polymer film 10 include a fluorocarbon resin (for example, perfluorosulfonic acid resin) or a hydrocarbon resin. The fuel cell 1 may be a system in which a plurality of sheet-like membrane electrode assemblies 13 are stacked in the thickness direction, or a system in which a plurality of tube-shaped membrane electrode assemblies 13 are arranged. Further, when stainless steel is employed in the reformer, it is advantageous for suppressing embrittlement of stainless steel that is caused by, for example, holding at 400 to 900 ° C. for a long time. Furthermore, when stainless steel is employed in the reformer, for example, it is advantageous to suppress the sensitization of the stainless steel that is likely to occur by maintaining the reforming apparatus at 500 to 850 ° C.

  As shown in FIGS. 1 and 2, the reformer 2 includes a combustion unit 30 that functions as a heating unit formed by a combustion burner, a reforming unit 34 that is heated by the combustion unit 30, and a reforming unit 34. A ring-shaped evaporation part 36 provided on the outer peripheral part, a ring-shaped CO oxidation removing part 37 (CO reduction part) provided on the outer peripheral part of the evaporation part 36, and combustion passages 32, 33, 35 Have. The reforming section 34 has a cylindrical shape having a central axis along the vertical direction, and reforms the reforming raw material to generate a reformed gas. The reforming section 34 has a cylindrical combustion passage 32 that faces the combustion section 30. A cylindrical combustion passage 33 is formed coaxially so as to surround the reforming portion 34. A cylindrical combustion passage 35 is coaxially formed outside the combustion passage 33 so as to communicate with the combustion passage 33. A cylindrical heat insulating portion 31 is formed coaxially between the combustion passage 33 and the combustion passage 35. Further, an evaporation portion 36 for evaporating the raw water is coaxially formed so as to surround the combustion passage 35. A CO oxidation removal unit 37 (also referred to as a CO selective oxidation unit) is coaxially formed adjacent to the evaporation unit 36. Therefore, the evaporation unit 36 and the CO oxidation removal unit 37 can transfer heat to each other and can exchange heat. Here, the evaporating unit 36 and the CO oxidation removing unit 37 may be arranged non-coaxially. In short, both need only be able to exchange heat with each other.

  As shown in FIGS. 1 and 2, the reforming portion 34 has an inner passage 34i, an outer passage 34p, and a turning portion 34m. The evaporation unit 36 is heated by the reforming unit 34 heated by the combustion unit 30. Since the cylindrical CO oxidation removal unit 37 is disposed so as to surround the evaporation unit 36, the outer peripheral part of the evaporation unit 36 and the inner peripheral part of the CO oxidation removal unit 37 can exchange heat with each other. Adjacent. During operation of the reformer 2, since the temperature of the CO oxidation removing unit 37 is generally higher than the temperature of the evaporation unit 36 at which liquid phase water evaporates, the CO oxidation removing unit 37 is connected to the evaporation unit 36. Give heat. The outer peripheral portion of the CO oxidation removing portion 37 is covered with a cylindrical heat insulating material 39 (heat insulating portion) having a high heat insulating property in order to surround and retain the temperature. However, as shown in FIG. 2, the heat insulating material 39 is not provided in the vicinity of the inlet 37 i to which the reformed gas that has passed through the CO shift unit 5 is supplied in the CO oxidation removal unit 37. Therefore, the lower end 39u of the heat insulating material 39 does not reach the inlet 37i. The main reason is that the temperature of the reformed gas is slightly higher than the activation temperature of the catalyst 37e of the CO oxidation removing unit 37, and thus the reformed gas is cooled.

  The reforming unit 34 includes a carrier that supports a reforming catalyst 34e (for example, nickel-based or ruthenium-based) that promotes a reforming reaction. The activation temperature range of the reforming catalyst 34e is generally 300 to 800 ° C., but is not limited thereto. If the temperature of the reforming unit 34 deviates greatly from the activation temperature range, the reforming reaction of the reforming unit 34 may be impaired. Based on the following formula (1), the reforming unit 34 performs steam reforming based on the reforming raw material and steam to generate a reformed gas containing hydrogen. The reformed gas contains carbon monoxide. In the reforming section 34, the shift reaction of the following formula (2) also occurs.

  Furthermore, as shown in FIGS. 1 and 2, the reformer 2 functions as a heat exchange unit 4 disposed below the reforming unit 34 and a CO purification unit disposed below the heat exchange unit 4. A CO shift unit 5 and a warm-up unit 47 having an electric heater disposed between the CO shift unit 5 and the heat exchange unit 4 are provided. Here, the heat exchange unit 4 is provided downstream of the evaporation unit 36, and the CO shift unit 5 is provided downstream of the heat exchange unit 4.

  The CO shift unit 5 promotes a shift reaction using water vapor based on the following formula (2), and reduces CO contained in the reformed gas. The CO shift unit 5 includes a carrier that supports a shift catalyst 5e (for example, a copper-zinc catalyst). The active temperature range of the shift catalyst 5e is generally 160 to 300 ° C., but is not limited thereto. If the temperature of the CO shift unit 5 greatly deviates from the activation temperature range, the shift reaction of the CO shift unit 5 may be impaired, and carbon monoxide may not be sufficiently purified. The concentration of CO contained in the reformed gas purified by the CO shift unit 5 is generally 0.01 to 1% in molar ratio, although it depends on the reforming raw material. It is not something that can be done. The CO shift unit 5 has a passage 5i, a passage 5v, and a turning portion 5m. The outlet 5p of the CO shift unit 5 and the oxidation air passage 75 are connected by a purification passage 400 via the second merge region M2.

The CO oxidation removing unit 37 is disposed downstream of the CO shift unit 5, and CO is converted into CO based on the following formula (3) from hydrogen and CO contained in the reformed gas purified by the CO shift unit 5. Thus, the selective oxidation reaction that is selectively oxidized and reduced is promoted. The CO oxidation removing unit 37 has a ceramic (for example, alumina) carrier that supports a catalyst 37e (for example, a ruthenium-based, platinum-based, platinum-ruthenium-based noble metal-based catalyst). In an oxygen-containing atmosphere, the activation temperature range of the catalyst 37e is generally 100 to 220 ° C. In a hydrogen-containing atmosphere, the activation temperature range of the catalyst 37e is generally 200 to 450 ° C. However, it is not limited to this. If the temperature of the CO oxidation removing unit 37 greatly deviates from the activation temperature range in the oxygen-containing atmosphere, the selective oxidation reaction in the CO oxidation removing unit 37 may be impaired. The concentration of CO contained in the reformed gas purified by the CO oxidation removing unit 37 is generally 10 ppm or less. However, it is not limited to this.
Formula (1) ... CH ₄ + H ₂ O → 3H ₂ + CO
Formula (2) ... CO + H ₂ O → H ₂ + CO ₂
Formula (3) ... CO + 1 / 2O ₂ → CO ₂
Since the CO shift unit 5 is disposed upstream of the CO oxidation removing unit 37, when the reforming apparatus 2 is operated, the CO shift unit 5 is executed in the order of Expression (2) → Expression (3).

  According to the present embodiment, the CO shift unit 5 becomes rich in hydrogen during the operation of the reformer 2, and is in a reducing condition. For this reason, even when the catalyst 5e of the CO shift unit 5 is oxidized, the catalyst 5e is easily reduced during operation of the reformer 2. However, the catalyst 37e of the CO oxidation removing unit 37 is not easily reduced only during operation of the reformer. In a state where oxygen is supplied to the CO oxidation removing unit 37, an active temperature range (for example, 100 to 220 ° C.) of the catalyst 37e of the CO oxidation removing unit 37 exists. If this temperature is exceeded, it is said that it is preferable not to exceed 220 ° C. since the deterioration of the catalyst 37e easily proceeds in an oxidizing atmosphere. However, when the composition of the catalyst 37e is changed, the temperature is also changed.

  Next, the passage system will be described. As shown in FIG. 1, a fuel passage 62 connected to the fuel supply source 61 through a valve 25a is provided. The fuel of the fuel supply source 61 may be gaseous fuel, liquid fuel, or pulverized fuel. Specifically, hydrocarbon fuel and alcohol fuel are exemplified. For example, city gas, LPG, kerosene, methanol, dimethyl ether, gasoline, biogas and the like are exemplified. The fuel passage 62 includes a combustion fuel passage 62a connected to the combustion section 30 of the reforming section 34 via a valve 25a and a pump 27a, and a pump 27b, a desulfurizer 62x and a valve 25b at the inlet 4i of the heat exchange section 4. And a reforming raw material passage 62c connected via each other. An air passage 72 (oxygen supply unit) connected to the air supply source 71 is provided. The air passage 72 is connected to the combustion air passage 73 connected to the combustion unit 30 of the reforming unit 34 through the pump 27c, and to the inlet 37i of the CO oxidation removal unit 37 through the air purification filter 72x, the pump 27d, and the valve 25d. It has an oxidation air passage 75 (oxygen supply part).

  As shown in FIGS. 1 and 2, a reforming water passage 82 (water supply unit) is provided that connects the water tank 81 and the inlet 36i of the evaporation unit 36 via a pump 27m and a valve 25m. Furthermore, an anode gas passage 100 (reformed gas discharge passage) that connects the outlet 37p of the CO oxidation removing unit 37 and the inlet 11i of the fuel electrode 11 of the fuel cell 1 via a valve 25e (outlet side valve) is provided. . In the anode gas passage 100, a pressure sensor 105 (see FIGS. 1 and 2) is disposed as pressure detection means for detecting the pressure P1 inside the reformer 2. The outlet 37p of the CO oxidation removing unit 37 is formed on the upper side of the CO oxidation removing unit 37 in the height direction. An off-gas passage 110 that connects the outlet 11p of the fuel electrode 11 of the fuel cell 1 and the combustion unit 30 via a valve 25f (outlet side valve) is provided. The off gas passage 110 discharges the anode off gas after the power generation reaction. A bypass passage 150 is provided that connects the off gas passage 110 and the anode gas passage 100 via a valve 25h (an outlet side valve that communicates with outside air).

  As shown in FIG. 1, a cathode gas passage 200 that connects the air supply source 71 and the inlet 12 i of the oxidant electrode 12 of the fuel cell 1 is provided. The cathode gas passage 200 communicates with the pump 27k and the valve 25k. As shown in FIG. 1, a combustion exhaust gas passage 250 is provided for releasing the combustion exhaust gas combusted in the reforming section 34 to the outside. A steam passage 300 is provided that connects the outlet 36p of the evaporation section 36 of the reformer 2 and the reforming raw material passage 62c via the first merge region M1. The upper end portion 300 e of the water vapor passage 300 is connected to the outlet 36 p of the evaporation portion 36. The lower end portion 300f of the water vapor passage 300 is connected to the merge area M1. The pumps 27a, 27b, 27c, 27d, 27k, and 27m function as fluid conveying elements.

  As shown in FIGS. 1 and 2, the outlet 5 p of the CO shift unit 5 and the inlet 37 i of the CO oxidation removing unit 37 are connected by a purification passage 400. The reformed gas discharged from the outlet 5p of the CO shift unit 5 (with hydrogen as a main component (40 mol% or more) and containing carbon monoxide) flows upward in the direction of the arrow W2 through the purification passage 400, and enters the second combination. It is supplied to the inlet 37i of the CO oxidation removing unit 37 through the basin M2. The inlet 37 i is formed on the lower side in the height direction of the CO oxidation removing unit 37.

  Next, when the reforming apparatus 2 is started will be described with reference to FIG. In this case, the combustion air is supplied to the combustion unit 30 of the reforming unit 34 by the pump 27 c through the combustion air passage 73. Further, gaseous combustion fuel is supplied to the combustion section 30 of the reforming section 34 through the combustion fuel passage 62a by the valve 25a and the pump 27a. As a result, the combustion section 30 is ignited and heated, and as a result, the reforming section 34 is heated so as to be suitable for the reforming reaction (for example, 600 to 800 ° C.). The evaporating unit 36 and the CO oxidation removing unit 37 together with the reforming unit 34 and the combustion passage 35 are also heated to a high temperature.

  Thereafter, the reforming water (water before the reforming reaction) is supplied from the water tank 81 and the reforming water passage 82 to the inlet 36i of the evaporation section 36 via the pump 27m and the valve 25m. The reformed water is steamed in the high temperature evaporator 36 of the reformer 2. The generated water vapor reaches the first merge region M1 through the water vapor passage 300 from the outlet 36p of the evaporation section 36. The first merge region M1 is a region where the steam or condensed water flowing through the steam passage 300 and the reforming raw material flowing through the reforming raw material passage 62c merge. On the other hand, the reforming raw material is supplied to the inlet 4i of the heat exchanging unit 4 through the desulfurizer 62x, the reforming raw material passage 62c, and the first merge region M1 by the valve 25a, the pump 27b, and the valve 25b. In the first merge region M1, the reforming raw material in the reforming raw material passage 62c and the steam in the steam passage 300 are merged and mixed. The merged mixed fluid is supplied to the inlet 4 i of the heat exchange unit 4.

  The mixed fluid passes through the first passage 4 a on the low temperature side of the heat exchange unit 4. At this time, heat exchange is performed with the high-temperature reformed gas flowing through the second passage 4c on the high temperature side of the heat exchange unit 4. For this reason, the mixed fluid before the reforming reaction is heated. The mixed fluid flows into the outer passage 34p of the reforming portion 34, flows in the direction of arrow A1, flows into the inner passage 34i through the turn-up portion 34m, and flows in the direction of arrow A2. At this time, the mixed fluid in which the steam (or condensed water) and the reforming raw material are mixed becomes a hydrogen-rich reformed gas by the reforming reaction shown in (1). This reformed gas contains carbon monoxide.

  Further, the high-temperature reformed gas that has undergone the reforming reaction flows from the reforming section 34 into the heat exchanging section 4. That is, the high-temperature reformed gas passes through the second passage 4c on the high temperature side of the heat exchange unit 4 from the reforming unit 34, thereby heating the mixed fluid in the first passage 4a on the low temperature side. Further, the reformed gas flows into the CO shift unit 5 from the inlet 5 i of the CO shift unit 5 through the warm-up unit 47. In the CO shift unit 5, a shift reaction using water vapor is performed as shown in the above formula (2). As a result, carbon monoxide contained in the reformed gas is reduced, and the reformed gas is purified.

Further, the reformed gas purified in the CO shift unit 5 flows from the outlet 5p of the CO shift unit 5 through the purification passage 400 in the direction of the arrow W2 and reaches the second merge region M2. Further, the reformed gas merges with the oxidizing air (oxygen component, selective oxidizing air used for the selective reaction in the CO oxidation removing unit 37) in the oxidizing air passage 75 (oxygen supply unit) in the second merge region M2. . Accordingly, the second merge region M2 is a region where the reformed gas flowing through the purification passage 400 and the oxidation air (oxygen component) flowing through the oxidation air passage 75 merge. The merged reformed gas flows into the CO oxidation removing unit 37 from an inlet 37 i formed at the lower part of the CO oxidation removing unit 37. In the CO oxidation removing unit 37, an oxidation reaction (CO + 1 / 2O ₂ → CO ₂ ) using oxygen is performed as shown in the above formula (3). As a result, CO contained in the reformed gas is purified and further reduced. The oxidation reaction is exothermic.

  The reformed gas thus purified is supplied as an anode gas from the outlet 37p of the CO oxidation removing section 37 to the inlet 11i of the fuel electrode 11 of the fuel cell 1 through the anode gas passage 100 and the valve 25e. The air functioning as the cathode gas is supplied to the inlet 12i of the oxidant electrode 12 of the fuel cell 1 through the cathode gas passage 200 by the pump 27k and the valve 25k. As a result, a power generation reaction occurs in the fuel cell 1 and electric energy is generated. The off gas after the power generation reaction of the anode gas (the gas discharged from the fuel cell 1) may contain hydrogen that has not been used for the power generation reaction. For this reason, the off gas is supplied to the combustion unit 30 of the reforming unit 34 through the off gas passage 110 and burned, and becomes a heat source of the combustion unit 30.

  In addition, at the time of starting the reforming apparatus 2, the stability of the reformed gas composition may not always be sufficient. For this reason, the valve 25e and the valve 25f are closed at the start of activation. In this state, the reformed gas discharged from the outlet 37p of the CO oxidation removing unit 37 passes through the valve 25h (outlet side valve), and is sent to the combustion unit 30 through the bypass passage 150 and the off-gas passage 110 to burn. It becomes a heat source for the unit 30. As time elapses from the start of the reforming device 2, the composition of the reformed gas becomes stable. In this case, the valve 25h is closed and the valves 25e and 25f are opened. For this reason, the reformed gas discharged from the outlet 37p of the CO oxidation removing unit 37 is supplied as an anode gas to the inlet 11i of the fuel electrode 11 of the fuel cell 1 through the anode gas passage 100 and the valve 25e to generate a power generation reaction. used.

  As shown in FIG. 1, a CO shift unit temperature detector 55 that detects a temperature T11 on the upstream side (inlet side of the passage 5i) of the CO shift unit 5 is provided. A CO shift portion temperature detector 39 for detecting a temperature T31 in the vicinity of the turning portion 5m of the CO shift portion 5 is provided. A CO oxidation removal unit temperature detector 38 for detecting the upstream temperature T12 of the CO oxidation removal unit 37 is provided. Further, a reforming unit temperature detector 31t for detecting the temperature T1 on the outlet side of the reforming unit 34 is provided. A temperature detector 65 that detects the temperature T2 of the first joining region M1 where the steam and the reforming raw material join together is provided. As shown in FIG. 1, the control unit 500 that controls the reformer system includes an unillustrated microcomputer, input processing circuit, output processing circuit, and memory 502. Each signal of the start switch 504 and the stop switch 505 is input to the control unit 500.

  Now, the configuration of the main part of the present embodiment will be described. During operation of the reformer 2, reformed gas containing hydrogen as a main component (40 mol% or more) is generated. When the power generation operation of the fuel cell system is stopped, a reforming operation stop operation for stopping the reforming operation of the reformer 2 is performed. In this case, the pump 27m is stopped, and the supply of the reforming water to the evaporation unit 36 of the reformer 2 is stopped. Further, since the pump 27a is stopped, the combustion fuel (13A gas) is not supplied to the combustion unit 30, so the combustion of the combustion unit 30 is stopped. The reformer 2 is gradually cooled by heat dissipation over time. However, immediately after the operation is stopped, the reformer 2 is still at a high temperature due to residual heat, so that the liquid phase water remaining in the reformer 2 (mainly the evaporation section 36) is heated to become steam, and the reformer The pressure P1 inside 2 gradually increases.

At this time, the control unit 500 performs a reforming operation stop operation for performing the operations (i) to (iii).
(I) The control unit 500 closes the valves 25a, 25b, 25d, and 25m (these valves are inlet side valves).
(Ii) After a first predetermined time (for example, 0.5 to 20 seconds, 0.5 to 10 seconds) has elapsed since the time when the inlet side valve was closed, the control unit 500 controls the valve 25e (the fuel electrode of the fuel cell). The closing operation is performed to close the valve 25h (the outlet side valve communicating with the outside air) and the valve 25f (the outlet side valve). That is, the outlet side valve is closed with a time delay after the inlet side valve is closed.
(Iii) Liquid phase water remaining in the reformer 2 is heated by residual heat to be steamed. For this reason, the pressure P1 inside the reformer 2 rises to a predetermined pressure (for example, 5 kPa, gauge pressure). Then, the control unit 500 maintains the valve 25a (valve 25b), the valve 25d, and the valve 25m (these are the inlet side valves) while closing the valve 25h (outlet side valve) for the sixth predetermined time (Δt). To release. Thereby, the high pressure inside the reformer 2 is released. Thereafter, an opening / closing operation for closing the valve 25h (the outlet side valve connected to the outside air via the combustion exhaust gas passage 250) again is performed. Here, the operation (iii) may be performed once or a plurality of times. In short, it is preferable to open the valve 25h each time the pressure P1 inside the reformer 2 rises to a predetermined pressure due to steaming. As described above, when the inside of the reformer 2 rises to a predetermined pressure, the valve 25h (outlet side valve) is opened each time to release the pressure, so that the pressure P1 inside the reformer 2 rises excessively. Is suppressed. Therefore, the pressure-resistant structure of the reformer 2 need not be excessive.

  When the above-described series of reforming operation stop operations is performed, the entire reformed gas generated in the reformer 2 is suppressed from being discharged to the outside of the reformer 2. Therefore, a considerable amount of the reformed gas containing hydrogen as a main component can be actively left inside the reformer 2. That is, the valve 25a, the valve 25b, the valve 25d, and the valve 25m (these are inlet side valves) are closed, and the valve 25e, the valve 25h (these are outlet side valves) and the valve 25f are closed. It is possible to leave as much as possible the reformed gas mainly containing hydrogen having a property in the reformer 2. As a result, during the stop operation of the reformer 2 and during standby, the oxidative deterioration of the catalysts 34e, 37e, 5e carried on the reformer 2 is suppressed. Therefore, the durability of the catalyst is improved.

  By the way, when the operation of the reforming apparatus 2 is stopped, the steam is condensed as the reforming apparatus 2 in the high temperature state is cooled, so that excessive negative pressure may occur inside the reforming apparatus 2. is there. In this case, there is a possibility that outside air may excessively enter the interior of the reformer 2 through the valve due to excessive negative pressure. In this case, since the outside air is oxygen-containing air, the catalysts 34e, 37e, 5e inside the reformer 2 may be oxidized and deteriorated while the reformer 2 is on standby. In order to suppress this, it is preferable to make the valves corresponding to the above-described inlet side valve and outlet side valve expensive with a high pressure-resistant sealing force with a strong closing force. However, such an inlet side valve and an outlet side valve are expensive and are not preferable from the viewpoint of cost reduction.

  As described above, according to the present embodiment, the reformed gas containing hydrogen as a main component is actively left inside the reformer 2, so even if the reformer 2 is cooled, the reformer Excessive negative pressure in 2 is suppressed. Therefore, the outside air containing oxygen is suppressed from excessively entering the reformer 2. Also in this sense, the oxidative deterioration of the catalysts 34e, 37e, 5e carried on the reformer 2 is suppressed, and the durability of the catalyst is improved. Therefore, for valves corresponding to both the inlet side valve and the outlet side valve, it is not a special valve with a strong closing force and a high pressure-resistant sealing force. Can be used. Therefore, it can contribute to the cost reduction of the reformer 2.

Immediately after the reforming operation stop operation, if the reforming section 34 is still in a high temperature state, a reforming reaction may occur due to the reforming raw material and moisture remaining in the reforming section 34. In this case, the gas volume increases. For example, if the reforming raw material contains CH ₄ , it was 2 mol before the reaction due to CH ₄ + H ₂ O → 3H ₂ + CO, but it becomes 4 mol after the reaction, and the gas volume increases. For this reason, according to the present embodiment, the valve 25a, the valve 25b, the valve 25d, and the valve 25m (inlet) are opened while the valve 25h (outlet valve) communicating with the outside air is opened while the valves 25e and 25f are closed. Close the side valve. Then, the valve 25h is closed after the first predetermined time has elapsed. As a result, as much reformed gas containing hydrogen as the main component can be left in the reformer 2 as much as possible. In this case, the gas inside the reformer 2 is discharged to the outside via the valve 25h (an outlet side valve communicating with the outside air) while suppressing the oxidative deterioration of the catalysts 34e, 37e, 5e inside the reformer 2. Can be made. Thereby, it can respond to the increase in gas volume. Although the first predetermined time varies depending on the type of the valve 25h (outlet side valve), the range of 5 to 25 seconds and the range of 10 to 20 seconds are more preferable. During the first predetermined time, a predetermined amount of water vapor in the reformer is discharged through the valve 25h (outlet side valve), so that the negative pressure resulting from the condensation of water vapor can be suppressed and hydrogen can be changed as much as possible. Can remain in the quality device. That is, if the first predetermined time is too short, the discharge of water vapor is insufficient, and the negative pressure suppression effect is reduced. If the first predetermined time is too long, the residual amount of hydrogen decreases. As described above, as much of the reformed gas containing hydrogen as the main component can remain in the reformer 2 as much as possible, oxidative deterioration of the catalysts 34e, 37e, 5e inside the reformer 2 is suppressed, This is advantageous for extending the life of the catalyst.

  In this regard, according to the present embodiment, the controller 500 temporarily opens the valve 25a and the valve 25b (these are the inlet side valves) while driving the pump 27b at the end time of the reforming operation stop operation. Thus, the gaseous reforming raw material (13A gas) is charged into the reformer 2. As a result, excessive negative pressure inside the reformer 2 is suppressed. Therefore, both the valve 25a, the valve 25b (inlet side valve) and the valve 25h (outlet side valve) are not expensive special valves having a high closing force and a high pressure-resistant sealing force. A simple valve can be used. That is, a valve that does not necessarily have a high pressure-resistant sealing force can be employed. That is, according to the present embodiment, outside air is allowed to enter the reformer 2. Here, since the valve for which the pressure-resistant sealing force is not so high has a small spring force for closing, the electromagnetic force for opening the valve against the spring force is small, which can contribute to the saving of electric energy. Oxygen contained in the outside air is consumed because it reacts with hydrogen of the reformed gas remaining in the reforming section 34 to generate water. Therefore, even if outside air enters the reformer 2, the oxygen contained in the air is prevented from adversely affecting the catalysts 34e, 37e, 5e of the reformer 2.

  According to the present embodiment, although the outside air is allowed to enter the reforming unit 34, most of the outside air is inert nitrogen. Furthermore, since the reformed gas mainly containing reducing hydrogen remains in the reformer 2, oxygen contained in the outside air that has actively entered the reformer 2 and Then, the hydrogen remaining in the reformer 2 reacts to consume oxygen. In this way, oxygen that has entered the reformer 2 is consumed and reduced, which is advantageous in suppressing the oxidative degradation of the catalysts 34e, 37e, and 5e.

  As described above, according to the present embodiment, when the operation of the reformer 2 is stopped, an excessive negative pressure in the reforming unit 34 is introduced in order to introduce the gaseous reforming raw material into the reforming unit 34. Is suppressed. For this reason, even if outside air enters into the reformer 2, the amount of outside air entering is about a specified amount (for example, 40 kPa, gauge pressure). With this amount of outside air intrusion, consumption of all the hydrogen remaining inside the reformer 2 can be suppressed, and hydrogen can be favorably left inside the reformer 2. For this reason, it is advantageous in suppressing the oxidative deterioration of the catalysts 34e, 37e, 5e carried on the reformer 2.

  According to the present embodiment, in the reforming operation stop operation, the control unit 500 drives the pump 27c to flow air as a cooling gas into the combustion unit 30 of the reformer 2 via the air passage 73, and combustion It is discharged from the combustion exhaust gas passage 250 through the passage 32. As a result, the reformer 2 is actively cooled by air. Therefore, slow cooling of the reforming unit 34 after the operation of the reformer 2 is stopped is suppressed. Thus, in order to promote the cooling of the reformer 2, the deterioration of the constituent materials of the reformer 2 is suppressed. For example, when alloy steel such as stainless steel is used for the reformer 2, slow cooling at a high temperature (around 475 ° C.) is suppressed. For this reason, it becomes advantageous for suppressing high temperature degradation, such as 475 degreeC embrittlement.

  Further, when stainless steel is adopted as a constituent material of the reformer 2, it is advantageous for suppressing embrittlement of the stainless steel that is caused, for example, by holding at 400 to 900 ° C. for a long time. Furthermore, when stainless steel is employed in the reformer, for example, it is advantageous to suppress the sensitization of stainless steel that is likely to occur by holding at 500 to 850 ° C. for a predetermined time.

  According to the present embodiment, it is preferable that the temperature of the CO oxidation removing unit 37 is temporarily set to 200 ° C. or higher (preferably 200 to 400 ° C.) while hydrogen remains in the reformer 2 and the process is terminated. . Thereby, the catalyst 37e inside the CO oxidation removing unit 37 can be reduced to promote regeneration of the catalyst 37e. As the above method, for example, power is generated for 1 to 10 minutes at the minimum output (300 W when the rated output is 1 kW) immediately before the end of power generation, the residual water vapor in the evaporation unit 36 is reduced, and the temperature T2 of the CO oxidation removal unit 37 is An example is a method of stopping power generation after confirming that the temperature has reached 105 ° C. or higher and entering an end operation. As the above method, a heat insulating means may be disposed between the evaporation unit 36 and the CO oxidation removal unit 37.

Since the present embodiment basically has the same configuration and effect as the first embodiment, FIGS. 1 and 2 are applied mutatis mutandis. FIG. 3 shows a timing chart. In FIG. 3, time ta means the time when power generation ends and the reforming operation stop operation starts. The time tb means a time at which the reforming operation stop operation is finished and the standby of the reformer 2 is started. The time tc means the time when the standby is completed and the operation for starting the reformer 2 is started. Further, in FIG. 3, a characteristic line W <b> 1 indicates the pressure P <b> 1 inside the reformer 2. A characteristic line W2 indicates the amount of residual hydrogen remaining in the reformer 2 (actually measured value: calculated from the actually measured hydrogen concentration value). A characteristic line W3 indicates a ratio (actual measurement value) between the pressure P (H ₂ ) of H _{2 and} the pressure P (H ₂ 0) of H ₂ 0 inside the reformer 2. The characteristic line WE (P (H ₂ ) / P (H ₂ 0) represents the oxidation-reduction characteristic (oxidation-reduction) of the highly important catalyst 37e among the catalysts supported on the reforming unit 34 in the reformer 2. In the region above the characteristic line WE, the oxidation of the catalyst 37e is suppressed, and in the region below the characteristic line WE, the catalyst 37e is oxidized.

  Also in this embodiment, the reformed gas containing hydrogen as a main component is generated by the operation of the reformer 2. Thereafter, when the power generation operation of the fuel cell ends, the control unit 500 stops the reforming operation of the reformer 2 at time ta.

  At this time, the controller 500 performs a reforming operation stop operation. First, in the reforming operation stop operation, at timing t1, the control unit 500 closes the valves 25a, 25b, 25d, and 25m (inlet side valves) from the open state, and also opens the valves 25e and 25f (outlet side valves). Close from state. Here, as shown in FIG. 3, the valve 25h (outlet side valve) is closed at a timing t2 delayed by a first predetermined time Δtx from the timing t1. That is, from the timing t1, the valve 25h is opened for a first predetermined time Δtx (for example, 5 to 20 seconds).

  When the above-described operation is performed, the reformed gas mainly composed of hydrogen generated in the reformer 2 is discharged to the outside of the reformer 2 while remaining inside the reformer 2 as much as possible. . That is, the reformed gas containing hydrogen as a main component is not discharged to the outside of the reformer 2 as much as possible. Therefore, the reformed gas containing hydrogen having reducibility as a main component can be left in the reformer 2 as much as possible. Therefore, the oxidative deterioration of the catalysts 34e, 37e, 5e can be suppressed.

  Here, a method in which the valve 25h is not opened for a predetermined time Δtx from the timing t1 in FIG. 3 is also conceivable. In this case, since the valve 25h is closed from the timing t1, the gas containing hydrogen and water vapor inside the reformer 2 cannot be discharged early. For this reason, when the valve 25 h is first opened due to the relief pressure of the reformer 2, the gas tends to return to the combustion unit 30 in large quantities via the valve 25 h and the off-gas passage 110. In this case, there is a possibility that a re-ignition sound or the like is generated in the combustion unit 30. With respect to this point, the method of opening the valve 25h for the predetermined time Δtx from the timing t1 as in the present embodiment is adopted, so that the hydrogen-containing gas inside the reformer 2 can be discharged early. In this case, when the valve 25h is opened for a predetermined time Δtx, the gas containing hydrogen returns to the combustion unit 30 through the valve 25h and the off-gas passage 110, but the gas containing hydrogen because the combustion unit 30 is still at a high temperature. Can continue to burn without generating a re-ignition sound or the like.

  Further, according to the present embodiment, the control unit 500 maintains the state in which the valve 25a, the valve 25b, the valve 25d, and the valve 25m (the inlet side valve of the reformer 2) are closed, that is, the reformer 2 is sealed. To do. In this case, since the vaporization of the liquid phase water remaining inside the high-temperature reformer 2 proceeds, the pressure P1 of the reformer 2 increases as shown by the line portion W1b of the characteristic line W1. To do. At the timing t4 when the pressure P1 rises to a predetermined pressure P2 (for example, 5 kPa, gauge pressure), the valve 25h (outlet side valve) is momentarily opened for a short time (Δt, a sixth predetermined time). As a result, the high pressure inside the reformer 2 is released (pressure release process), and excessive pressure increase is suppressed. Even after that, since the liquid phase water is vaporized by the residual heat of the high-temperature reformer 2, the internal pressure of the reformer 2 rises as shown by the line portion W1c of the characteristic line W1. . Then, at the timings t4, t5, and t6 when the pressure P1 inside the reformer 2 rises to the predetermined pressure P2, the valve 25h is momentarily opened for a short time (Δt), and the high pressure inside the reformer 2 is increased. It escapes to the outside air (pressure release process) and suppresses excessive pressure increase of the reformer 2. For this reason, it is not necessary to increase the pressure resistance of the reformer 2 excessively.

  According to the present embodiment, as indicated by the characteristic line W4, the control unit 500 continuously drives the pump 27c from the initial stage in the stop operation of the reforming operation, so that the air passes through the combustion air passage 73. A forced cooling process for supplying the combustion unit 30 and forcibly cooling the reformer 2 is performed. Here, the air supplied to the combustion unit 30 flows through the combustion passage 32 and the combustion passage 33 while cooling the reformer 2, and is discharged from the combustion exhaust gas passage 250 to the outside air. In this case, since the warmed air passes, the CO oxidation removal unit 37 tends to rise in temperature, and can contribute to the regeneration process of the catalyst 37e of the CO oxidation removal unit 37.

  Now, with the passage of time, the temperature T1 of the reforming section 34 decreases. At a timing t8 when the temperature T1 of the reforming section 34 is lowered to a predetermined temperature on the low temperature side (for example, 100 to 200 ° C., particularly 150 ° C.), using this as a trigger signal, the pump 27c is turned off, The supply to the combustion unit 30 via 73 is stopped. As a result, the forced cooling process for cooling the reformer 2 is stopped. Further, as shown in FIG. 3, at timing t8, the valves 27a and 25b (inlet side valves) are opened while the pump 27b is driven, and the gaseous reforming raw material is introduced into the reformer 2 for a predetermined time tr. It is supplied once (in some cases, a plurality of times) through the reforming raw material passage 62c. As a result, the pressure P1 of the pressure sensor increases to a predetermined pressure P3 (for example, about 20 kPa) as indicated by a line portion W1r of the characteristic line W1. Thereafter, since the cooling of the reformer 2 further proceeds and the condensation of water vapor proceeds, the pressure P1 of the pressure sensor gradually decreases as indicated by the line portion W1e of the characteristic line W, and the pressure P1 of the pressure sensor is moderately negative. The pressure Pe (for example, −15 kPa) is reached, and the reformer 2 waits. Thereby, excessive negative pressure of the reformer 2 is suppressed.

  As described above, according to the present embodiment, when the temperature T1 of the reforming unit 34 is lowered to a predetermined temperature (100 to 200 ° C., for example, 150 ° C.) at which the reforming raw material does not coking in the reforming unit 34, the gas The raw material for reforming is supplied into the reformer 2. For this reason, coking in the reforming unit 34 is suppressed, and the durability of the reforming unit 34 can be improved.

  At the time tc, the standby of the reformer 2 is finished and the start-up operation of the reformer 2 is started. In starting the start-up operation of the reformer 2, the pump 27b is driven and the valves 25a and 25b (inlet side valves) are opened for a predetermined time Δtm (for example, 0.5 to 15 seconds) from the timing tc. As a result, the gaseous reforming raw material is supplied to the interior of the reforming section 34 to increase the pressure inside the reformer 2. When the pressure P1 does not decrease during a predetermined time TK (for example, 300 sec) with the pressure increased in this way, the control unit 500 indicates that the piping system has not leaked and the piping system is normal. It is determined that When it is determined that the piping is normal at the start of the reforming operation in this way, the power supply is stopped to suppress standby power when the reforming device 2 is stopped and kept waiting until the next operation. However, it is also possible not to perform monitoring.

Table 1 shows the concentration of hydrogen contained in the gas, the number of moles of hydrogen contained in the gas, and the pressure ratio (PH ₂ / PH ₂ O when the above-described reformer was used and the test for stopping the operation of the reformer was performed. ) Is an example. The calculated value and the actually measured value basically correspond to each other.

  FIG. 4 shows a third embodiment. The present embodiment basically has the same configuration and effect as the second embodiment. 1 and 2 apply mutatis mutandis. Hereinafter, a description will be given centering on the difference from the second embodiment. As described above, according to the second embodiment, as shown in FIG. 3, the valve 25h (outlet side valve) is closed at the timing t2 delayed by the predetermined time Δtx from the timing t1. In this regard, in the present embodiment, Δtx is abolished. Therefore, as can be understood from FIG. 4, the valves 25a, 25b, 25d, and 25m (inlet side valves) are closed from the timing t1 (time ta). The valves 25h, 25e, and 25f (outlet side valves) are closed.

  The present embodiment has basically the same configuration and operation effects as the first and second embodiments. 1 and 2 apply mutatis mutandis. Also in this embodiment, the reforming operation of the reformer 2 is stopped at the end of the operation of the fuel cell system. In this case, the pump 27m is stopped and the supply of the reforming water to the evaporation unit 36 is stopped. Since the pump 27a (combustion fuel conveyance source) and the pump 27c (combustion air conveyance source) are stopped, the combustion fuel and the combustion air are not supplied to the combustion unit 30. Therefore, the combustion of the combustion unit 30 is stopped, and the reformer 2 is gradually cooled as time elapses. However, since the reformer 2 immediately after the stop of operation still has residual heat and is at a high temperature, the water remaining in the reformer 34 becomes steam, and the pressure P1 inside the reformer 2 gradually increases.

At this time, the control unit 500 performs the reforming operation stop operation for performing the operations (i) to (iii) as in the first and second embodiments.
(I) The valves 25a, 25b, 25d and 25m (these valves are inlet side valves) are closed. At this time, the valve 25e and the valves 25h and 25f (these valves are outlet valves) are opened.
(Ii) After a first predetermined time (for example, 0.5 to 10 seconds, 0.5 to 20 seconds) has elapsed since the time when the inlet side valve was closed, the valves 25e, 25h, and 25f (these valves are outlet side valves) ) Is closed.
(Iii) When the pressure P1 inside the reformer 2 rises to a predetermined pressure, the valve 25a, the valve 25b, the valve 25d, the valve 25m (the valve is an inlet side valve), and the valve 25e are closed (the reformer 2) The valve 25h (the outlet side valve communicating with the outside air) is opened for a sixth predetermined time while maintaining the closed state. Thereby, the pressure inside the reformer 2 is released. Thereafter, an opening / closing operation for closing the valve 25h (outlet side valve) again is performed.

  The above operation (iii) may be performed once or a plurality of times. In short, it is preferably performed every time the pressure P1 inside the reformer 2 increases to a predetermined pressure. Thereby, the pressure resistance of the reformer 2 does not have to be excessive.

  The control unit 500 drives the pump 27c from the beginning of the reforming operation stop operation, supplies air to the combustion unit 30 via the combustion air passage 73, and forcibly cools the reforming device 2. It is carried out. Thereby, it is suppressed that the constituent material of the reformer 2 is maintained at a high temperature for a long time. According to the present embodiment, when the temperature T1 of the reforming section 34 has decreased to a predetermined temperature (100 to 200 ° C., particularly 150 ° C.), it is used as a trigger signal to turn off the pump 27c. As a result, the supply of air to the combustion unit 30 via the combustion air passage 73 is stopped, and the forced cooling process for forcibly cooling the reformer 2 is stopped.

  When the temperature T1 of the reforming section 34 has decreased to a predetermined temperature (for example, 100 to 200 ° C., particularly 150 ° C.) as the reformer 2 is stopped, the valves 25a and 25b (inlet side valves) are turned off. While being opened, the pump 27b is driven, and the gaseous reforming raw material is supplied into the reforming apparatus 2 once or a plurality of times for a predetermined time tr. At this time, the temperature of the reforming unit 34 is still high, and is equal to or higher than the reforming reaction possible temperature, so that the reforming raw material undergoes a reforming reaction, and hydrogen gas is actively generated in the reforming unit 34. Here, hydrogen gas has reducibility. Therefore, it is advantageous for suppressing the oxidative deterioration of the catalysts 34e, 37e, 5e carried on the reformer 2 during stoppage or standby. In this way, the reformed gas mainly containing reducing hydrogen remains in the reformer 2. The reforming raw material in which the reforming reaction has not occurred remains in the reformer 2 as it is. For this reason, even if the reformer 2 is cooled, excessive negative pressure inside the reformer 2 is suppressed. Therefore, excessive outside air is prevented from entering the reformer 2. Therefore, the oxidative deterioration of the catalysts 34e, 37e, 5e carried on the reformer 2 is suppressed, and the durability of the catalyst is improved.

  As described above, according to this embodiment, even when the reforming device 2 is cooled, excessive negative pressure in the reforming device 2 is suppressed. Therefore, as for the valves corresponding to both the inlet side valve and the outlet side valve, it is possible to use a general valve with a low price as well as a special valve having a high pressure-resistant sealing force. Contributes to system cost reduction. Further, in this embodiment, even if air enters the reforming section 34, most of the air is inert nitrogen. Since oxygen contained in the air reacts with hydrogen of the reformed gas remaining in the reforming section 34 to generate water, it is consumed considerably. Accordingly, it is possible to suppress the oxygen contained in the air from adversely affecting the catalysts 34e, 37e, 5e.

  Since the present embodiment basically has the same configuration and operational effects as the first and second embodiments, FIGS. 1 and 2 are applied mutatis mutandis. The CO oxidation removing unit 37 as the CO reducing unit includes a ceramic (for example, alumina) carrier that supports a catalyst 37e (for example, a ruthenium-based, platinum-based, platinum-ruthenium-based noble metal-based catalyst). Since oxygen is supplied to the CO oxidation removing unit 37, the oxidative deterioration of the catalyst 37e is likely to proceed, and there is a particular demand for suppressing the oxidative deterioration of the catalyst 37e and thus improving the durability. Also in the present embodiment, as described above, in the reforming operation stop operation, hydrogen remains in the reformer 2 including the CO oxidation removing unit 37. In a hydrogen-containing atmosphere (hydrogen-rich atmosphere), the activation temperature range (regeneration temperature range) of the catalyst 37e is generally 200 ° C. or higher, particularly 220 ° C. or higher, and the range is 200 to 450 ° C.

  By the way, when the fuel cell system is stopped, the control unit 500 performs a reforming operation stop operation for stopping the reforming operation of the reformer 2. After stopping the supply of the reforming water, the reforming raw material, and the oxidizing air, the combustion of the combustion unit 30 is continued for the second predetermined time for the second predetermined time. When all of the reforming water, the reforming raw material, and the oxidizing air are stopped, the supply of the reformed gas to the fuel cell 1 is stopped.

  Further explanation will be given. The controller 500 performs the following control to promote activation and regeneration of the catalyst 37e supported on the CO oxidation removing unit 37. That is, before the closing operation for closing the inlet side valve and the outlet side valve, the control unit 500 performs the combustion reaction in the combustion unit 30 (heating unit) of the reformer 2 for a second predetermined time (for example, 2 to 60 minutes, 5 to 30 minutes) (not limited to this) and the heating of the reforming unit 34 is continued.

  In other words, the supply of the reforming water to the reformer 2 is stopped, the supply of the reforming raw material is stopped, the supply of the oxidizing air is stopped, the reforming operation is thus stopped, and the reformed gas is supplied. Despite the generation being stopped, combustion fuel and combustion air are supplied to the combustion unit 30, the combustion fuel burns in the combustion unit 30, and the reforming unit 34 and the like are heated. In this case, as described above, the combustion reaction is performed in the combustion unit 30 for the second predetermined time, so that the temperature of the evaporation unit 36 is maintained as high as possible. For this reason, the flow rate of residual water in the evaporator 36 is reduced or eliminated, and the temperature of the evaporator 36 rises. As a result, the temperature of the CO oxidation removing unit 37 adjacent to the evaporation unit 36 also rises. Therefore, the CO oxidation removing unit 37 is maintained at a temperature as high as possible. As a result, the catalyst 37e carried on the CO oxidation removing unit 37 is reduced in a state where hydrogen remains in the CO oxidation removing unit 37 even though the above-described reforming operation stop operation is performed. The CO oxidation removing unit 37 is maintained at a regeneration temperature at which regeneration is possible, for example, for 3 to 30 minutes. For this reason, the catalyst 37e built in the CO oxidation removal unit 37 is reduced with hydrogen. Thereby, the oxidative deterioration of the catalyst 37e is suppressed, the durability of the catalyst 37e is improved, and the life can be extended. That is, whenever the reforming operation of the reformer 2 is stopped, the catalyst 37e of the CO oxidation removing unit 37 is regenerated.

  Since the present embodiment basically has the same configuration and operational effects as the first and second embodiments, FIGS. 1 and 2 are applied mutatis mutandis. When stopping the fuel cell system, the control unit 500 performs a reforming operation stop operation for stopping the reforming operation of the reformer 2. In this case, the control unit 500 performs the following control in order to promote activation and regeneration of the catalyst 37e that is easily deteriorated. That is, the supply of the reformed gas to the fuel cell 1 is stopped (this is called the fuel cell stop. The oxidant gas that is cathode air is supplied to the fuel cell 1 for a while). Thereafter, the reforming operation of the reforming device 2 is continued for a third predetermined time while the oxidizing air is stopped while the supply flow rate of the reforming water and the reforming raw material is decreased, and then the operation of the reforming device 2 is performed. (Stops all reforming water, reforming raw material, and combustion section).

  In other words, the reforming operation of the reformer 2 is continued for a third predetermined time (for example, 2 to 60 minutes, 5 to 30 minutes, but not limited to this), although the power generation operation of the fuel cell 1 is stopped. Thereby, the temperature of the evaporation part 36 is maintained as high as possible. For this reason, the amount of residual water in the evaporator 36 is reduced or eliminated. As a result, the temperature decrease rate of the CO oxidation removing unit 37 is reduced. Alternatively, the CO oxidation removing unit 37 rises in temperature as the evaporation unit 36 rises in temperature. Therefore, the CO oxidation removing unit 37 is maintained at a temperature as high as possible. Therefore, the CO oxidation removing unit 37 is favorably maintained at a regeneration temperature at which the catalyst 37e of the CO oxidation removing unit 37 can be regenerated, for example, for 3 to 30 minutes. At this time, since hydrogen remains in the CO oxidation removing unit 37, the catalyst 37e carried on the CO oxidation removing unit 37 is reduced with hydrogen. Thereby, the oxidative deterioration of the catalyst 37e is suppressed, and the durability of the catalyst 37e is improved.

  Since the present embodiment basically has the same configuration and operational effects as the first and second embodiments, FIGS. 1 and 2 are applied mutatis mutandis. When stopping the fuel cell system, the control unit 500 performs a reforming operation stop operation for stopping the reforming operation of the reformer 2. In this case, the control unit 500 performs the following control in order to promote activation and regeneration of the catalyst 37e that is easily deteriorated. That is, the controller 500 reduces the output of the fuel cell 1 and reduces the reforming operation of the reformer 2. In this case, the power generation operation of the fuel cell 1 is continued for a fourth predetermined time (for example, 1 to 60 minutes, 5 to 30 minutes) in the low output region. The low output region can be set to 5 to 50% and 10 to 40% when the power generation output during rated operation of the fuel cell is displayed as 100%. For example, it can be the minimum load region of the fuel cell. Here, the rating refers to the limit in use guaranteed by the manufacturer when operating under specified conditions, and is usually displayed on a nameplate or the like.

  At this time, the fuel cell 1 is operated for power generation for a fourth predetermined time in the minimum load operation region, and the reforming operation of the reformer 2 is reduced. For this reason, combustion fuel and combustion air are supplied to the combustion unit 30, the combustion fuel is burned in the combustion unit 30, the reforming unit 34 and the like are heated, and the heat of the reforming unit 34 is converted into the evaporation unit 36 and Heat is transferred to the CO oxidation removal unit 37 and the like, reforming water is supplied to the evaporation unit 36, and a gaseous reforming raw material is supplied to the reforming unit 34. In this case, the supply of reforming water and the like are controlled so that the S / C (steam / carbon) of the reforming unit is close to 3.

  That is, since the valve 25a is opened and the pump 27a is driven, combustion fuel is supplied to the combustion unit 30 from the combustion fuel passage 62a. Further, since the pump 27 c is driven, combustion air is supplied from the combustion air passage 73 to the combustion unit 30. Further, since the valves 25a and 25b are opened and the pump 27b is driven, the reforming material is supplied to the reforming unit 34 from the reforming material passage 62c. Furthermore, the valve 25m of the reforming water passage 82 is opened, the pump 27m is driven, and the reforming water is supplied from the reforming water passage 82 to the evaporation section 36.

  As described above, also in the reforming operation stop operation, since the combustion reaction is performed in the combustion unit 30, the reforming unit 34 is heated, the temperature drop of the evaporation unit 36 is suppressed, or the evaporation unit 36 is heated. Therefore, the temperature of the evaporator 36 is maintained as high as possible. For this reason, the flow rate of residual water in the evaporator 36 is reduced or eliminated. For this reason, the temperature of the CO oxidation removing unit 37 is increased, or the temperature decrease of the CO oxidation removing unit 37 is suppressed. Therefore, in the reforming operation stop operation, the CO oxidation removing unit 37 is well maintained at the regeneration temperature of the catalyst 37e of the CO oxidation removing unit 37. At this time, as described above, since the hydrogen remains in the CO oxidation removing unit 37, the catalyst 37e supported on the CO oxidation removing unit 37 is reduced with hydrogen. Thereby, the oxidative deterioration of the catalyst 37e is suppressed, and the durability of the catalyst 37e is improved. After the fourth predetermined time has elapsed, the control unit 55 stops the operation of the fuel cell 1 and the reformer 2.

  FIG. 5 shows an eighth embodiment. The present embodiment corresponds to the seventh embodiment, and basically has the same configuration and operational effects as the first and second embodiments. Therefore, FIGS. 1 and 2 are applied mutatis mutandis. The control unit 500 performs a reforming operation stop operation for stopping the reforming operation of the reformer 2. In this case, the control unit 500 performs the following control in order to promote activation and regeneration of the easily deteriorated catalyst 37e before performing the closing operation for closing the inlet side valve and the outlet side valve. That is, while maintaining the reforming operation of the reformer 2, the power generation operation of the fuel cell 1 is set to the lowest load operation region, and this is continued for a fourth predetermined time TW (for example, 1 to 60 minutes, 5 to 30 minutes). When the output during rated operation is displayed relative to 100%, the minimum load operation region can be 10 to 30% (or 10 to 25%).

  FIG. 5 shows a timing chart of the present embodiment. This timing chart is basically the same as the timing chart shown in FIG. In FIG. 5, time ta means the time when the power generation of the fuel cell 1 is completed and the reforming operation stop operation is started. Therefore, at time ta, valves 25a, 25b, and 25d (inlet valve of reformer 2) and valves 25m and 25e (outlet valve of reformer 2, valve 25h in FIG. 5 are opened by Δtx). Closed. The time tb means a time when the reforming operation stop operation is finished and the standby of the reformer 2 is started. The time tc means the time when the standby is completed and the operation for starting the reformer 2 is started.

  In FIG. 5, a time tf before the closing time ta at which the inlet valve of the reformer 2 and the outlet valve of the reformer 2 are closed is a time at which an end command for terminating the power generation operation of the fuel cell system is output. Means. As shown in FIG. 5, from this time tf, that is, before the closing operation in which the inlet valve and the outlet valve are closed, the rope control unit 500 sets the fuel cell 1 to the minimum load operation region and performs a predetermined time TW (1 Power generation operation for up to 20 minutes). For this reason, the control part 500 reduces the flow volume of combustion air from Va1 to Va2 from the time tf. The flow rate of the combustion fuel is decreased from Vf1 to Vf2. The flow rate of the reforming raw material is decreased from Vm1 to Vm2. The flow rate of the reforming water is decreased from Vw1 to Vw2. The flow rate of the oxidizing air is decreased from Vo1 to Vo2. The flow rate means a flow rate per unit time.

  Here, the range of Va2 / Va1 = 0 to 0.99 and the range of 0.01 to 0.99 are exemplified. The range of Vf2 / Vf1 = 0.1-0.99 is illustrated. The range of Vm2 / Vm1 = 0.1-0.99 is illustrated. Vw2 / Vw1 = 0.1-0.99 is illustrated. The range of Vo2 / Vo1 = 0.1-0.99 is illustrated. However, it is preferable that Vm2 is such that S (steam) / C (carbon) is 3 or more in order to prevent coking.

  Thus, while maintaining the reforming operation of the reformer 2, the flow rate of the reformed gas (hydrogen) generated by the reformer 2 is reduced, and the power generation operation of the fuel cell 1 is set to the minimum load operation region.

  In the lowest load operation region of the fuel cell 1, the valve 25h (the outlet side valve of the reformer 2) is closed, but the valves 25e and 25f used for power generation are open. Therefore, the reformed gas is supplied to the fuel electrode 1 of the fuel cell 1, and the anode off-gas generated by the fuel cell 1 is discharged from the off-gas passage 110 and the valve 25 f to the combustion unit 30, thereby combusting the combustible component of the anode off-gas. Burn at 30.

  Thus, at the end of the end of the power generation operation in the fuel cell power generation system, the reformed gas is supplied to the fuel electrode 11 of the fuel cell 1 as the anode gas. Therefore, the liquid phase water staying in the membrane electrode assembly of the fuel cell 1 can be discharged as much as possible. In this case, there is an advantage that flooding (flow path closing phenomenon due to liquid phase water) can be suppressed when the fuel cell 1 is operated next for power generation.

  Also in this embodiment, the reformed gas containing hydrogen as a main component is generated by the operation of the reformer 2. Thereafter, when the power generation operation of the fuel cell ends, the control unit 500 stops the reforming operation of the reformer 2 at time ta. At this time, the controller 500 performs a reforming operation stop operation. First, in the reforming operation stop operation, at timing t1, the valves 25a, 25b, 25d, and 25m (inlet side valves) are closed from the open state, and the valves 25e and 25f (outlet side valves) are also closed from the open state. The valve 25h (outlet side valve) is closed at a timing t2 delayed by a first predetermined time Δtx from the timing t1. That is, the valve 25h is opened for a predetermined time Δtx (for example, 5 to 20 seconds) from the timing t1.

  When the above-described operation is performed, the reformed gas mainly composed of hydrogen generated in the reformer 2 is discharged to the outside of the reformer 2 while remaining inside the reformer 2 as much as possible. . That is, the reformed gas containing hydrogen as a main component is not discharged to the outside of the reformer 2 as much as possible. Therefore, the reformed gas containing hydrogen having reducibility as a main component can be left in the reformer 2 as much as possible. Therefore, the oxidative deterioration of the catalysts 34e, 37e, 5e can be suppressed.

  Further, according to the present embodiment, the control unit 500 maintains the state in which the valve 25a, the valve 25b, the valve 25d, and the valve 25m (the inlet side valve of the reformer 2) are closed, that is, the reformer 2 is sealed. To do. In this case, since the vaporization of the liquid phase water remaining inside the high-temperature reformer 2 proceeds, the pressure P1 of the reformer 2 increases as shown by the line portion W1b of the characteristic line W1. To do. Using the timing t4 when the pressure P1 rises to a predetermined pressure P2 (for example, 5 kPa, gauge pressure) as a trigger, the valve 25h (outlet side valve) is momentarily opened for a short time (Δt). As a result, the high pressure inside the reformer 2 is released (pressure release process), and excessive pressure increase is suppressed. Even after that, since the liquid phase water is vaporized by the residual heat of the high-temperature reformer 2, the internal pressure of the reformer 2 is reduced as shown by the line portions W1b and W1c of the characteristic line W1. To rise. Then, using the timings t4, t5, and t6 when the pressure P1 inside the reformer 2 rises to the predetermined pressure P2 as a trigger, the valve 25h is instantaneously opened for a short time (Δt). As a result, the high pressure inside the reformer 2 is released to the outside air (pressure release process), and excessive pressure increase of the reformer 2 is suppressed. For this reason, it is not necessary to increase the pressure resistance of the reformer 2 excessively.

  According to the present embodiment, as indicated by the characteristic line W4, the control unit 500 continuously drives the pump 27c from the initial stage in the stop operation of the reforming operation, so that the air passes through the combustion air passage 73. A forced cooling process for supplying the combustion unit 30 and forcibly cooling the reformer 2 is performed. Here, the air supplied to the combustion unit 30 flows through the combustion passage 32 and the combustion passage 33 while cooling the reformer 2, and is discharged from the combustion exhaust gas passage 250 to the outside air. In this case, since the air used for cooling is warmed, from time ta to time tb, the evaporation unit 36 is heated for a while, and the CO oxidation removal unit 37 adjacent to the evaporation unit 36 is heated for a while. Accordingly, the pump 27c can function as a temperature maintaining element that raises the temperature of the evaporation unit 36 and the CO oxidation removal unit 37 or suppresses the temperature drop when stopping the reforming operation of the reformer 2.

  Now, with the passage of time, the temperature T1 of the reforming section 34 decreases. At a timing t8 when the temperature T1 of the reforming section 34 is lowered to a predetermined temperature on the low temperature side (for example, 100 to 200 ° C., particularly 150 ° C.), using this as a trigger signal, the pump 27c is turned off, The supply to the combustion unit 30 via 73 is stopped. As a result, the forced cooling process for cooling the reformer 2 is stopped. Further, at timing t8, the valves 27a and 25b (inlet side valves) are opened while driving the pump 27b, the gaseous reforming material is supplied for a predetermined time tr, and the reforming material passage 62c is provided inside the reforming apparatus 2. 1 time (multiple times in some cases). As a result, the pressure P1 of the pressure sensor increases to a predetermined pressure P3 (for example, about 20 kPa) as indicated by a line portion W1r of the characteristic line W1. Thereafter, since the cooling of the reformer 2 further proceeds and the condensation of water vapor proceeds, the pressure P1 of the pressure sensor gradually decreases as indicated by the line portion W1e of the characteristic line W, and the pressure P1 of the pressure sensor is moderately negative. The pressure Pe (for example, −15 kPa) is reached, and the reformer 2 waits. Thereby, the pressurization of the reformer 2 is suppressed.

  As described above, according to this embodiment, when the temperature T1 of the reforming unit 34 is lowered to a predetermined temperature (100 to 200 ° C., for example, 150 ° C.) at which coking does not occur in the reforming unit 34, The raw material is supplied into the reformer 2. For this reason, coking in the reforming unit 34 is suppressed, and the durability of the reforming unit 34 can be improved.

  At the time tc, the standby of the reformer 2 is finished and the start-up operation of the reformer 2 is started. In starting the start-up operation of the reformer 2, the pump 27b is driven and the valves 25a and 25b (inlet side valves) are moved from the timing tc to a predetermined time Δtm (for example, 0.1 to 15 seconds, which is not limited to this). No) Open. As a result, the gaseous reforming raw material is supplied to the interior of the reforming section 34 to increase the pressure inside the reformer 2. When the pressure P1 does not decrease during a predetermined time TK (for example, 300 seconds) in the state where the pressure is increased in this way, the control unit 500 has no gas leakage in the piping system, and the piping system is normal. It is determined that Thus, when it is determined that the piping is normal at the start of the reforming operation, when the operation of the reforming apparatus 2 is stopped and put on standby, the power supply is stopped and monitoring is performed to suppress standby power. You can also avoid doing it.

  FIG. 6 shows a ninth embodiment. The present embodiment basically has the same configuration and operational effects as the eighth embodiment. 1 and 2 apply mutatis mutandis. Hereinafter, a description will be given centering on the difference from the eighth embodiment. According to the eighth embodiment shown in FIG. 5, as described above, the valve 25h (outlet side valve) is closed at the timing t2 delayed by a predetermined time Δtx from the timing t1. However, in this embodiment, Δtx is abolished as shown in FIG. Therefore, from the timing t1 (time ta), the valves 25a, 25b, 25d, and 25m (inlet side valve) and the valves 25h, 25e, and 25f (outlet side valve) are simultaneously closed.

  FIG. 7 shows a tenth embodiment. The present embodiment has basically the same configuration and operation effects as the first and second embodiments. As shown in FIG. 7, a ring-shaped heat insulating layer 700 having a lower end 700 d is disposed between the evaporation unit 36 and the CO oxidation removal unit 37. For this reason, when the reforming operation of the reformer 2 is stopped, the temperature of the CO oxidation removing unit 37 is easily maintained even when the evaporation unit 36 is cooled. As a result, the CO oxidation removing unit 37 is well maintained at the regeneration temperature of the catalyst 37e of the CO oxidation removing unit 37. At this time, as described above, since hydrogen remains in the CO oxidation removing unit 37, the catalyst 37e carried on the CO oxidation removing unit 37 is reduced. Thereby, the oxidative deterioration of the catalyst 37e is suppressed, and the durability of the catalyst 37e is improved.

(Other)
In the first embodiment described above, the reformer 2 integrally incorporates the evaporation unit 36, but the evaporation unit may be a separate body. Although the reformer 2 integrally incorporates the heat exchange unit 4, the heat exchange unit may be a separate body. In the first embodiment described above, the reforming unit 34 is disposed on the upper side and is disposed on the lower side of the CO shift unit 5, but is not limited to this, and may be reversed. The present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications within a range not departing from the gist. The following technical idea can be understood from the above description.

  (Additional Item 1) A reformer having a reformer that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture, and a controller that controls the reformer In addition to the reforming unit, the reformer system includes a heating unit that heats the reforming unit, and a reformed gas that is transferred from the reforming unit and generated in the reforming unit. And a CO reduction unit containing a catalyst for reducing the CO component generated, and after the reformer is operated to generate reformed gas, the reforming operation stop operation for stopping the reforming operation of the reformer is performed. In carrying out the operation, the control unit continues the heating of the reforming unit by the heating unit of the reforming apparatus for a second predetermined time to suppress the temperature decrease of the evaporation unit and slow down the temperature decreasing rate of the CO reducing unit, A reformer system characterized in that the catalyst in the CO reduction unit is reduced in a remaining state.

  (Additional Item 2) In Additional Item 1, an inlet-side valve that is disposed upstream of the reformer and supplies a reforming raw material to the reformer of the reformer, and on the downstream side of the reformer In a reformer system comprising an outlet-side valve that is disposed and discharges the reformed gas generated by the reformer from the reformer, the reformer is operated to generate the reformed gas Thereafter, when performing the reforming operation stop operation for stopping the reforming operation of the reformer, the control unit closes both the inlet side valve and the outlet side valve, and the inlet side valve. The outlet side valve is opened when the inside of the reformer rises to a predetermined pressure while maintaining the closed state, and then the opening / closing operation for closing the outlet side valve is performed. Reformer system.

  The present invention can be used for a reformer used in a fuel cell system, a hydrogen generation system, or the like.

1 is a system diagram of a reformer according to Embodiment 1. FIG. 1 is a system diagram of a main part of a reforming apparatus according to Embodiment 1. FIG. The timing chart which it concerns on Example 2 and a control part performs at the time of a driving | operation stop of a reformer is shown. The timing chart which concerns on Example 3 and is performed when a control part stops the operation | movement of a reformer is shown. The timing chart which concerns on Example 8 and a control part performs at the time of operation stop of a reformer is shown. The timing chart which concerns on Example 9 and is performed when a control part stops the operation | movement of a reformer is shown. FIG. 10 is a cross-sectional view showing a reforming apparatus according to Example 10;

Explanation of symbols

  1 is a fuel cell, 2 is a reformer, 25a and 25m are valves (inlet side valves), 25h is a valve (outlet side valve), 30 is a combustion part (heating part), 34 is a reforming part, and 36 is an evaporation part , 37 is a CO oxidation removal unit (CO reduction unit), 37e is a catalyst, 37p is an outlet, 4 is a heat exchange unit, 5 is a CO shift unit, and 500 is a control unit.

Claims (8)

A reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture;
An inlet-side valve disposed upstream of the reformer and supplying a reforming raw material to the reformer of the reformer;
An outlet side valve that is disposed downstream of the reformer and discharges the reformed gas generated by the reformer from the reformer;
In a reformer system comprising a control unit that controls the inlet side valve and the outlet side valve,
In performing the reforming operation stop operation for stopping the reforming operation of the reformer after the reformer is operated to generate the reformed gas, the control unit includes:
A closing operation for closing both the inlet side valve and the outlet side valve;
While maintaining the state where the inlet side valve is closed, when the inside of the reformer rises to a predetermined pressure, the outlet side valve is opened, and then the opening / closing operation for closing the outlet side valve is performed. A reformer system characterized by that.   The control unit according to claim 1, wherein, in the closing operation, the control unit closes the inlet side valve while opening the outlet side valve, and closes the outlet side valve after a first predetermined time has elapsed. Reformer system.   3. The control unit according to claim 1, wherein the control unit opens the inlet-side valve after the opening / closing operation in the reforming operation stop operation, thereby allowing gaseous reforming raw material to enter the reforming unit. A reformer system that suppresses excessive negative pressure inside the reformer by introducing the reformer.   3. The control unit according to claim 1, wherein, in the reforming operation stop operation, the control unit opens the inlet side valve when the temperature of the reforming unit is equal to or higher than the reforming reaction temperature after the opening / closing operation. A reformer system characterized in that hydrogen is generated by a reforming reaction in the reforming section by introducing a gaseous reforming raw material into the reforming section. A reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture;
An inlet-side valve disposed upstream of the reformer and supplying a reforming raw material to the reformer of the reformer;
An outlet side valve that is disposed downstream of the reformer and discharges the reformed gas generated by the reformer from the reformer;
In a reformer system comprising a control unit that controls the inlet side valve and the outlet side valve,
In addition to the reforming unit, the reformer is provided so as to be able to exchange heat with the heating unit that heats the reforming unit, an evaporation unit that generates water vapor to be supplied to the reforming unit, and the evaporation unit. A CO reduction unit containing a catalyst for reducing CO components contained in the reformed gas generated in the reforming unit,
In performing the reforming operation stop operation for stopping the reforming operation of the reformer after the reformer is operated to generate the reformed gas, the control unit includes:
Heating of the reforming unit by the heating unit of the reforming apparatus is continued for a second predetermined time to suppress the temperature decrease of the evaporation unit while slowing the temperature decrease rate of the CO reduction unit, and hydrogen remains in the CO reduction unit. A reformer system characterized in that the catalyst of the CO reduction unit is reduced in a state. A reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture;
An inlet-side valve disposed upstream of the reformer and supplying a reforming raw material to the reformer of the reformer;
An outlet side valve that is disposed downstream of the reformer and discharges the reformed gas generated by the reformer from the reformer;
In a reformer system comprising a control unit that controls the inlet side valve and the outlet side valve,
In addition to the reforming unit, the reformer is provided so as to be able to exchange heat with the heating unit that heats the reforming unit, an evaporation unit that generates water vapor to be supplied to the reforming unit, and the evaporation unit. A CO reduction unit containing a catalyst for reducing CO components contained in the reformed gas generated in the reforming unit,
In performing the reforming operation stop operation for stopping the reforming operation of the reformer after the reformer is operated to generate the reformed gas, the control unit includes:
After the power generation operation of the fuel cell is stopped, the reforming operation of the reformer is continued for a third predetermined time to suppress the temperature decrease of the evaporation unit, while the temperature decrease rate of the CO reduction unit is slowed down, A reformer system characterized in that the catalyst of the CO reduction unit is subjected to a reduction treatment in a state in which residual gas remains. A reformer having a reforming unit that generates a reformed gas containing hydrogen by reacting a gaseous reforming raw material with moisture;
An inlet-side valve disposed upstream of the reformer and supplying a reforming raw material to the reformer of the reformer;
An outlet side valve that is disposed downstream of the reformer and discharges the reformed gas generated by the reformer from the reformer;
In a reformer system comprising a control unit that controls the inlet side valve and the outlet side valve,
In addition to the reforming unit, the reformer is provided with a heating unit for heating the reforming unit, an evaporation unit for generating water vapor to be supplied to the reforming unit, and heat exchange with the evaporation unit. A CO reduction unit that incorporates a catalyst for reducing the CO component contained in the reformed gas generated in the reforming unit,
In performing the reforming operation stop operation for stopping the reforming operation of the reformer after the reformer is operated to generate the reformed gas, the control unit includes:
While maintaining the reforming operation of the reformer, the power generation operation of the fuel cell is generated for a fourth predetermined time in a low output region, the temperature decrease rate of the CO reduction unit is reduced, and hydrogen remains in the CO reduction unit A reformer system characterized in that the catalyst of the CO reduction unit is reduced in a state.   The reformer system according to claim 1, wherein the control unit causes a cooling gas to flow into a heating unit that heats the reforming unit in the reforming operation stop operation. .

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