JP4830567B2 - Hydrogen generator - Google Patents

Description

  The present invention relates to a hydrogen generator for reforming a reforming raw material such as a hydrocarbon to generate hydrogen.

In a fuel reformer that obtains hydrogen-rich gas from hydrocarbons containing sulfur compounds by steam reforming, when the catalytic activity of the reforming catalyst is reduced due to sulfur poisoning, the reforming section containing the reforming catalyst is heated. A technique is known in which the catalytic activity of the reforming catalyst is recovered by heating at a section and supplying an inert gas or water vapor gas to the reforming section for a predetermined time (see, for example, Patent Document 1). Such a recovery operation of the catalyst activity is performed in a time zone other than the startup operation, the stop operation, and the normal operation operation of the fuel reformer.
JP 2000-351606 specification

  However, in the conventional technology as described above, when recovering the catalytic activity, energy such as fuel, electric power, and heat for heating the reforming unit with respect to the heating unit, that is, operation of the reforming unit (hydrogen rich gas) In order to generate a large amount of energy loss, it is necessary to supply energy that does not contribute directly. In particular, when steam gas is used to recover the catalyst activity, energy equivalent to latent heat for converting water into steam is further required, so that the problem of energy loss becomes significant and is improved from the viewpoint of energy efficiency. There is room for.

  An object of the present invention is to obtain a hydrogen generator capable of efficiently recovering the catalytic activity of a reforming catalyst in consideration of the above facts.

  In order to achieve the above object, a hydrogen generator according to claim 1 is a reforming in which a reforming reaction for generating a hydrogen-containing gas from a reforming raw material containing a sulfur component is carried out using a supported reforming catalyst. A heating unit that is disposed adjacent to the reforming unit and that heats the reforming unit so that the reforming reaction proceeds in the reforming unit by burning the supplied fuel; And a catalyst regeneration means for performing a regeneration step for recovering the activity of the reforming catalyst by supplying water vapor in the combustion exhaust gas of the heating section to the reforming section.

  In the hydrogen generator according to claim 1, when the reforming material comes into contact with the reforming catalyst in the reforming section, a reforming reaction occurs while absorbing heat supplied from the heating section, and a hydrogen-containing gas is generated. By the way, in a reforming section that reforms a reforming raw material containing a sulfur component to generate a hydrogen-containing gas, the reforming catalyst is poisoned by the sulfur component in the raw material during operation.

  When performing the regeneration process for recovering the catalytic activity of the reforming catalyst whose activity has been reduced by sulfur poisoning, the catalyst regeneration means supplies the steam in the combustion exhaust gas of the heating section to the reforming section. By supplying this high-temperature steam, the sulfur component on the reforming catalyst is removed, and the catalytic activity can be recovered. Here, since the water vapor in the combustion exhaust gas of the heating unit is used in the regeneration process, the energy efficiency is remarkably improved as compared with the configuration using the steam dedicated for regeneration. That is, for example, in a structure in which steam for recovering catalyst activity is introduced from the outside of the hydrogen generator in the regeneration process, a water tank, an evaporator for evaporating water (energy corresponding to latent heat), a heater (energy corresponding to sensible heat), etc. However, in the present hydrogen generator, a regeneration step for recovering the catalytic activity of the reforming catalyst by effectively utilizing the components (moisture) and exhaust heat in the combustion exhaust gas of the heating unit can be performed. Further, recovery of the catalyst activity (regeneration process) is also promoted by supplying heat from the heating unit.

  Thus, in the hydrogen generator according to claim 1, the catalytic activity of the reforming catalyst can be recovered efficiently. The catalyst regeneration means may be configured, for example, to selectively introduce water vapor in the combustion exhaust gas into the reforming section, or may be configured to introduce steam together with other components in the combustion exhaust gas into the reforming section. In particular, in a configuration in which oxygen slightly contained in the combustion exhaust gas is introduced into the reforming section together with water vapor, it is possible to achieve operating conditions that are more suitable for recovering the activity of the catalyst (promoting sulfur removal).

  A hydrogen generator according to a second aspect of the present invention is the hydrogen generator according to the first aspect, wherein the catalyst regeneration means includes a sulfur removal unit for removing sulfur components in the combustion exhaust gas.

  In the hydrogen generator according to claim 2, since the sulfur component in the combustion exhaust gas is removed by the sulfur removing unit, the sulfur component is prevented from being introduced into the reforming unit in the regeneration process. Thereby, the catalytic activity of the reforming catalyst can be recovered more efficiently.

  The hydrogen generator according to claim 3 is the hydrogen generator according to claim 1 or 2, wherein the catalyst regeneration means outputs a signal corresponding to the sulfur poisoning status of the reforming catalyst. Poison detection means, a regeneration switching device capable of switching between a state in which the combustion exhaust gas of the heating unit is discharged out of the system and a state in which it is led to the reforming unit, and a supply path for supplying the reforming raw material to the reformer A material switching device capable of switching between a state in which the reforming material is supplied to the reformer and a state in which the material supply to the reformer is stopped, and the modification based on an output signal of the poisoning detection means. When it is determined that the activity of the catalyst is lower than a set value, the raw material switching device is switched to the raw material supply stop side of the reformer, and the regeneration switching device is switched to the reformer of the combustion exhaust gas. And a control device that switches to the introduction side of It is.

  In the hydrogen generator according to claim 3, when the decrease in the catalyst activity is detected based on the output signal of the poisoning detection means, the control device switches the raw material switching device to supply the reforming raw material to the reformer. In addition to stopping, the regeneration switching device is switched to introduce the combustion exhaust gas (part of the steam) of the heating unit into the reformer. As a result, the reformer is automatically switched to the regeneration process, and the catalytic activity of the reforming catalyst is recovered as described above. After the recovery of the catalyst activity, the normal operation is performed in which the reforming reaction (hydrogen generation) is performed in the reforming section.

  As described above, since the reforming reaction is performed while monitoring the poisoning status of the reforming catalyst, that is, the catalytic activity, hydrogen is generated, so that a hydrogen-containing gas containing hydrogen at a high concentration can always be generated (supplied).

  According to a fourth aspect of the present invention, in the hydrogen generation apparatus according to the third aspect, the poisoning detection means includes a temperature detector that outputs a signal corresponding to the temperature of the reforming catalyst.

  In the hydrogen generator according to claim 4, the temperature of the reforming catalyst is detected by detecting the temperature rise of the reforming catalyst due to the stagnation of the reforming (endothermic) reaction due to sulfur poisoning of the reforming catalyst. The poisoning situation can be detected. The temperature detector is not limited to one that directly detects the temperature of the reforming catalyst, and may be one that detects the temperature of the outer shell (container) of the reforming unit, for example, It may be one that detects temperature.

  According to a fifth aspect of the present invention, there is provided the hydrogen generator according to the third or fourth aspect, wherein the poisoning detection means outputs a signal corresponding to the flow rate of the gas discharged from the reforming unit. Includes output flow detector.

  In the hydrogen generator according to claim 5, by detecting a decrease in the reforming amount (gas generation amount) due to the stagnation of the reforming (endothermic) reaction due to sulfur poisoning of the reforming catalyst, The poisoning status of the reforming catalyst can be detected.

  A hydrogen generation apparatus according to a sixth aspect of the present invention is the hydrogen generation apparatus according to any one of the third to fifth aspects, wherein the poisoning detection means is a concentration of gas discharged from the reforming unit. A gas concentration detector that outputs a signal corresponding to the above is included.

  In the hydrogen generator according to claim 6, a change in gas concentration (for example, a decrease in hydrogen concentration or an unreacted reforming raw material gas concentration caused by a stagnation of the reforming (endothermic) reaction due to sulfur poisoning of the reforming catalyst). By detecting the increase) with a gas concentration detector, it is possible to detect the poisoning status of the reforming catalyst.

  The hydrogen generator according to claim 7 is the hydrogen generator according to any one of claims 3 to 6, wherein the regeneration switching device guides the combustion exhaust gas from the heating unit to the outside of the system. It is provided with a regeneration pipe that branches from the discharge pipe and guides the combustion exhaust gas to the reforming section, and includes a valve that can open and close the regeneration pipe.

  In the hydrogen generator according to claim 7, when detecting a decrease in the catalyst activity based on the output signal of the poisoning detection means, the control device opens the valve so that the regeneration switching device is connected to the reformer. Switch to the combustion exhaust gas introduction side. In this way, the normal operation can be switched to the regeneration process by simply opening and closing the valve. The valve may be a three-way valve provided at the branch portion of the exhaust pipe that guides the combustion exhaust gas to the outside of the system and the regeneration pipe, and the on-off valve provided downstream of the branch portion of the regeneration pipe in the exhaust pipe In combination, the combustion exhaust gas may be circulated on the reformer side.

  A hydrogen generator according to an eighth aspect of the invention is the hydrogen generator according to any one of the third to seventh aspects, wherein the raw material switching device is switched to the raw material supply stop side of the reformer. Forcible switching means for forcibly operating the control device is further provided so as to switch the regeneration switching device to a side where the combustion exhaust gas is introduced into the reformer.

  In the hydrogen generator according to the eighth aspect, the operation state can be forcibly switched to the regeneration step by the forcible switching means. Thereby, for example, when the required amount of hydrogen generation is small, the number of times of switching to the regeneration process during operation and the cumulative switching time can be reduced by forcibly performing the regeneration process.

  A hydrogen generator according to a ninth aspect of the present invention is the hydrogen generator according to any one of the third to eighth aspects, wherein the raw material switching device is switched to the raw material supply side of the reformer and the regeneration is performed. Forcible switching means for forcibly operating the control device is further provided so as to switch the switching device to a discharge side of the combustion exhaust gas to the outside of the system.

  In the hydrogen generator according to claim 9, forcible switching means forcibly switches from the regeneration state to the operation state, or forcibly maintains the operation state (prohibits the transition from the operation state to the regeneration state). it can. Thus, for example, when hydrogen generation becomes necessary, or when the reforming section has not reached a predetermined temperature such as at the time of start-up, the reformed fuel is forcibly kept in a state where it does not shift to the regeneration process. Can be used efficiently for hydrogen generation and start-up characteristics can be improved.

  As described above, the hydrogen generator according to the present invention has an excellent effect that the catalytic activity of the reforming catalyst can be efficiently recovered. For example, when hydrocarbon is used as the reforming raw material, the reforming performance is deteriorated due to poisoning of the reforming catalyst. In addition to sulfur poisoning taken up in the present technology, the carbon catalyst contained in the hydrocarbon fuel is used. Although there is carbon poisoning (coking) due to deposition on the surface, the catalyst regeneration of the present technology also works effectively to regenerate the decrease in catalyst activity due to this carbon poisoning.

  A hydrogen generator 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.

  FIG. 1 shows a system configuration diagram (process flow sheet) of the hydrogen generator 10. As shown in this figure, a hydrogen generator 10 is a reforming unit (reactor) that generates a reformed gas containing hydrogen to be supplied to a hydrogen consuming device 12 such as a fuel cell or a hydrogen engine (internal combustion engine). 14 and a heating unit 16 for supplying heat for the reforming unit 14 to perform a reforming reaction are configured as main components. The reforming unit 14 carries a reforming catalyst 18 inside, and hydrogen gas is produced by catalytic reaction of the supplied hydrocarbon gas (gasoline, methanol, natural gas, etc.) and reforming gas (steam). Is generated (reforming reaction is performed).

The reforming reaction in the reforming unit 14 includes each reaction including the steam reforming reaction represented by the formula (1) as represented by the following formulas (1) to (4). Therefore, the reformed gas obtained in the reforming process includes hydrogen (H ₂ ), carbon monoxide (CO), methane (CH ₄ ), cracked hydrocarbons, unreacted raw material hydrocarbons (C _x H _y ), etc. Combustible gas and carbon dioxide (CO ₂ ), water (H ₂ O), and other non-flammable gases.

_{C n H m + nH 2 O} → nCO + (n + m / 2) H 2 ... (1)
_{C n H m + n / 2O} 2 → nCO + m / 2H 2 ... (2)
CO + H ₂ O⇔CO ₂ + H ₂ (3)
CO + 3H ₂ ＣＨCH ₄ + H ₂ O (4)
Since the steam reforming reaction of the main formula (1) in the reforming reaction is an endothermic reaction, the reforming unit 14 is operated at a temperature equal to or higher than a predetermined temperature by receiving heat supply from the heating unit 16. It has become so. The heating unit 16 includes an oxidation catalyst (not shown) and is provided adjacent to the reforming unit 14. The heating unit 16 is configured to bring the supplied fuel into contact with the oxidation catalyst together with oxygen to cause catalytic combustion. Thereby, the heating unit 16 is configured to supply the heat generated by the catalytic combustion as heat for maintaining the reforming reaction and the operating temperature in the reforming unit 14.

  The hydrogen generator 10 supplies combustion heat obtained by catalytic combustion of fuel in the heating unit 16 to the reforming unit 14 via the partition wall unit 15. For this reason, heat quantity can be directly given to the reforming section 14 without converting the heat quantity into temperature as in the configuration in which the reforming section 14 is heated via a heat medium (fluid) such as combustion gas. It is configured.

  The hydrogen generator 10 includes a raw material supply line 20 for supplying a hydrocarbon raw material to the reforming unit 14. The raw material supply line 20 has an upstream end connected to a discharge portion of a raw material pump (not shown) and a downstream end connected to a raw material inlet 14 </ b> A of the reforming unit 14. The hydrocarbon raw material slightly contains a sulfur component (sulfur compound) that does not contribute to the above reforming reaction. In addition, a water vapor supply line (not shown) is joined to the raw material supply line 20 so that water vapor and oxygen used for the above-described reforming reaction are supplied to the reforming unit 14 together with the hydrocarbon raw material. The hydrocarbon raw material is supplied to the reforming unit 14 in a state of being vaporized or atomized by a vaporizing means (not shown) such as an evaporator or an injection and mixed with water vapor or the like.

  Furthermore, the reformed gas outlet 14 </ b> B of the reforming unit 14 is connected to the upstream end of the hydrogen supply line 22 connected to the hydrogen consuming apparatus 12 at the downstream end. Thereby, the reformed gas containing the hydrogen produced in the reforming unit 14 at a high concentration is supplied to the hydrogen consuming apparatus 12.

  The hydrogen generator 10 also includes a fuel supply line 24 for supplying fuel to the heating unit 16. The fuel supply line 24 has an upstream end connected to a discharge portion of a fuel pump (not shown) and a downstream end connected to a fuel inlet 16 </ b> A of the heating unit 16. In this embodiment, the fuel combusted in the heating unit 16 is hydrocarbon, and is shared with the reforming raw material (stored in a common fuel tank). The fuel pump may be shared with the raw material pump. In this fuel supply line or fuel inlet 16A, a combustion support gas line (not shown) for supplying air containing combustion support gas (oxygen) is joined, and is vaporized or atomized in the same manner as the reforming raw material. A mixed gas obtained by mixing fuel and combustion-supporting gas is supplied to the heating unit 16.

  A flue gas line 26 is connected to the flue gas outlet 16B of the heating unit 16 as a discharge pipe for discharging the flue gas to the atmospheric discharge unit 25 outside the system. For example, a catalytic converter for purifying the combustion exhaust gas may be provided in the combustion exhaust gas line 26.

  The hydrogen generator 10 is provided with a catalyst regeneration means for removing the sulfur component from the reforming catalyst 18 and recovering the catalyst activity when the reforming catalyst 18 is sulfur poisoned. This will be specifically described below. As shown in FIG. 1, the hydrogen generator 10 includes a regeneration gas supply line 28 as a regeneration pipe that branches from the combustion exhaust gas line 26 and joins the raw material supply line 20. The regeneration gas supply line 28 is provided with a sulfur trap 30 as a sulfur removal unit for removing sulfur components in the combustion exhaust gas. The sulfur trap 30 includes an adsorbent that removes sulfur in the combustion exhaust gas by adsorption. As this adsorbent, for example, metal oxides such as zinc oxide, copper oxide, and zinc titanate can be used.

  Further, a valve constituting a raw material switching device is provided between the merging portion 20A of the regeneration gas supply line 28 in the raw material supply line 20 and the merging portion of the water vapor supply line located upstream of the merging portion 20A. V1 is disposed. Further, a valve V2 constituting a raw material switching device is disposed in the regeneration gas supply line 28 in the vicinity of the junction 20A (downstream of the sulfur trap 30). Each of the valves V1 and V2 is an open / close valve, and is configured to open and close the raw material supply line 20 and the regeneration gas supply line 28 according to a command from a catalyst regeneration controller 34 described later.

  Further, on the downstream side of the branch portion 26A of the regeneration gas supply line 28 in the combustion exhaust gas line 26, a valve V3 constituting a regeneration switching device is disposed, and in the vicinity of the branch portion 26A in the regeneration gas supply line 28 ( On the upstream side of the sulfur trap 30, a valve V4 constituting a regeneration switching device is disposed. Each of the valves V3 and V4 is an on-off valve, and is configured to open and close the combustion exhaust gas line 26 and the regeneration gas supply line 28 according to a command from a catalyst regeneration controller 34 described later. The valve V4 corresponds to the valve in the present invention, and the regeneration gas supply line 28 and the valves V3 and V4 correspond to the regeneration switching device, and these together with the valve V1 as the raw material switching device constitute the catalyst regeneration means in the present invention.

  Furthermore, in this embodiment, a regeneration gas discharge line 32 is provided which branches from the hydrogen supply line 22 and joins the downstream side of the valve V3 in the combustion exhaust gas line 26. In the hydrogen supply line 22, a valve V <b> 5 is disposed on the downstream side of the branch portion 22 </ b> A of the regeneration gas discharge line 32, and a valve V <b> 6 is disposed in the regeneration gas discharge line 32. Each of the valves V5 and V6 is an on-off valve, and opens and closes the hydrogen supply line 22 and the regeneration gas discharge line 32 according to a command from a catalyst regeneration controller 34 described later.

  The hydrogen generator 10 is a catalyst regeneration controller as a control device for switching between an operation mode in which the reforming unit 14 generates hydrogen-containing reformed gas and a regeneration mode in which the catalytic activity of the reforming catalyst 18 is recovered. 34 is provided. The catalyst regeneration controller 34 is electrically connected to the above-described valves V1, V2, V3, V4, V5, and V6, and controls the opening and closing thereof. The catalyst regeneration controller 34 is electrically connected to a temperature sensor 36 as poisoning detection means (temperature detector) and a manual regeneration switch 38 as forced switching means.

  The temperature sensor 36 outputs a signal corresponding to the temperature of the reforming catalyst 18. The manual regeneration switch 38 outputs an ON signal when it is turned ON by an operator, and outputs an OFF signal (0 signal) in other cases. The catalyst regeneration controller 34 normally selects the operation mode. When it is determined that the temperature of the reforming catalyst 18 exceeds a predetermined threshold based on the output signal of the temperature sensor 36, the operation is performed. It is configured to switch from the mode to the playback mode. Further, the catalyst regeneration controller 34 is configured to switch from the operation mode to the regeneration mode when the manual regeneration switch 38 is turned on. The control of the catalyst regeneration controller 34 will be described later together with the operation of this embodiment.

  The hydrogen generator 10 described above supplies high-concentration hydrogen to a fuel cell for supplying electric power to a motor for driving an automobile or a hydrogen engine for an automobile. The manual regeneration switch 38 is disposed at an appropriate position in the passenger compartment so that an occupant (driver) of the automobile can operate.

  Next, the operation of the embodiment will be described with reference to the flowchart of FIG.

  In the hydrogen generator 10 having the above configuration, the catalyst regeneration controller 34 normally selects the operation mode, and the valves V1, V3, V5 are opened and the valves V2, V4, V6 are closed as shown in FIG. Has been. Thereby, in the reforming unit 14, hydrocarbon raw material, water vapor, and oxygen are introduced from the raw material supply line 20. On the other hand, in the heating unit 16, a mixed gas of fuel and air is introduced from the fuel supply line 24, and these come into contact with the oxidation catalyst to cause catalytic combustion.

  Heat generated by catalytic combustion in the heating unit 16 is supplied to the reforming unit 14 via the partition wall 15, and in the reforming unit 14, the supplied hydrocarbon raw material, steam, and oxygen perform a steam reforming reaction. A reforming reaction represented by the formulas (1) to (4) is generated, and a reformed gas containing hydrogen at a high concentration is generated. This reformed gas is supplied to the hydrogen consuming apparatus 12 through the hydrogen supply line 22. On the other hand, the combustion exhaust gas from the heating unit 16 is discharged from the combustion exhaust line 26 to the atmospheric discharge unit 25.

  At this time, the catalyst regeneration controller 34 monitors (monitors) the output signal of the temperature sensor 36, that is, the poisoning status of the reforming catalyst 18. Specifically, as shown in FIG. 2, the catalyst regeneration controller 34 determines whether or not the regeneration condition is not established based on the output signal of the temperature sensor 36 in step S10. As shown in FIG. 5A, when the sulfur poisoning amount of the reforming catalyst 18 increases, the reforming reaction having an endothermic reaction as a main reaction stagnate while the heat supply from the heating unit 16 is maintained. From this, it is known that the temperature Tc of the reforming catalyst 18 increases. Then, the catalyst regeneration controller 34 determines that the regeneration condition is not satisfied when the temperature Tc is equal to or lower than the threshold value T0, and determines that the regeneration condition is satisfied when the temperature Tc exceeds the threshold value T0.

  The catalyst regeneration controller 34 that has determined that the regeneration condition is satisfied in step S10 (N for failure) is transferred to the regeneration mode from the operation mode in step S12. Specifically, as shown in FIG. 4, the opened valves V1, V3, V5 are closed, and the closed valves V2, V4, V6 are opened. As a result, the supply of the reforming raw material (that is, sulfur), water vapor, and oxygen to the reforming unit 14 is stopped, and the combustion exhaust gas from which the sulfur component is removed by the sulfur trap 30 is introduced into the reforming unit 14. The That is, in the regeneration mode, high-temperature water vapor and a small amount of oxygen in the combustion exhaust gas are supplied to the reforming catalyst 18 of the reforming unit 14. Further, the heat supply from the heating unit 16 to the reforming unit 14 is maintained.

  And since the combustion exhaust gas of the heating unit 16 contains a large amount of high-temperature steam, the reforming catalyst 18 is efficiently regenerated in a short time. That is, the sulfur component on the reforming catalyst 18 is removed, and the catalytic activity of the reforming catalyst 18 is restored. The exhaust gas after the regeneration of the reforming catalyst 18 is discharged from the combustion exhaust gas line 26 to the atmospheric discharge unit 25 via the hydrogen supply line 22 and the regeneration gas discharge line 32.

  After executing step S12, the catalyst regeneration controller 34 proceeds to step S14, and determines whether or not a predetermined time has elapsed since switching to the regeneration mode. When a predetermined time (a time set as a time for sufficient recovery of catalyst activity) has elapsed since switching to the regeneration mode, the catalyst regeneration controller 34 proceeds to step S16 and switches from the regeneration mode to the operation mode. That is, as shown in FIG. 3, the opened valves V2, V4, V6 are closed and the closed valves V1, V3, V5 are opened.

  If it is determined in step S10 that the catalyst regeneration condition is not satisfied (the catalyst poisoning amount is small), the catalyst regeneration controller 34 proceeds to step S18 and determines whether or not the manual regeneration switch 38 outputs an OFF signal. To do. If the manual regeneration switch 38 is outputting an OFF signal, the process proceeds to step S16 and the operation mode is maintained. On the other hand, if the manual regeneration switch 38 is outputting an ON signal, the process proceeds to step S12 to switch from the operation mode to the regeneration mode. The subsequent operation is as described above. A driver of an automobile to which the hydrogen generator 10 is applied turns on the manual regeneration switch 38 when the vehicle is stopped waiting for a signal, for example (when power is added to the fuel cell or the load of the hydrogen engine is small).

  Here, in the hydrogen generator 10, since the steam in the combustion exhaust gas of the heating unit 16 is used in the regeneration process, the energy efficiency is remarkably improved as compared with a configuration using steam exclusively for regeneration. That is, for example, in a structure in which steam for recovering catalyst activity is introduced from the outside of the hydrogen generator in the regeneration process, a water tank, an evaporator for evaporating water (energy corresponding to latent heat), a heater (energy corresponding to sensible heat), etc. However, in the present hydrogen generator 10, a regeneration process for recovering the catalytic activity of the reforming catalyst by effectively using the water vapor component and exhaust heat (latent heat and sensible heat) in the combustion exhaust gas of the heating unit 16 is performed. It can be carried out. In addition, since the heat supply from the heating unit 16 is maintained in the regeneration process, recovery of the catalyst activity is promoted.

  Thus, in the hydrogen generator 10 according to the embodiment, the catalytic activity of the reforming catalyst 18 can be efficiently recovered. Further, it has been experimentally confirmed that a small amount of oxygen contained in the combustion exhaust gas of the heating unit 16 contributes to the recovery of the catalytic activity of the reforming catalyst 18, and only steam is supplied to the reforming unit 14. As compared with the above, the catalytic activity of the reforming catalyst 18 can be recovered in a shorter time.

  Moreover, in the hydrogen generator 10, since the sulfur trap 30 is provided in the regeneration gas supply line 28, the sulfur component in the combustion exhaust gas is removed, and the sulfur component is introduced into the reforming unit 14 in the regeneration process. Is prevented. Thereby, the catalytic activity of the reforming catalyst can be recovered more efficiently (for a short time).

  Further, in the hydrogen generator 10, since the catalyst regeneration controller 34 automatically switches from the operation mode to the regeneration mode based on the output signal of the temperature sensor 36, hydrogen generation (reformation) in the operation mode is always performed with a high catalyst activity. Reaction), a hydrogen-containing gas containing hydrogen at a high concentration can always be generated and supplied to the hydrogen consuming apparatus 12.

  Furthermore, in the hydrogen generator 10, since the control objects by the catalyst regeneration controller 34 for switching between the operation mode and the regeneration mode are the valves V1 to V6, which are on-off valves, respectively, the regeneration process is performed with a simple structure and control. A possible configuration has been realized.

  In addition, since the hydrogen generation device 10 is switched to the regeneration mode by turning on the manual regeneration switch 38 by a vehicle occupant such as a driver, the number of automatic regeneration mode switching and the regeneration mode execution time during driving of the automobile are reduced. can do. Thereby, for example, in the configuration in which hydrogen is supplied to the fuel cell, the number of times and time depending on the power of the battery during traveling of the vehicle are reduced, and the battery load can be reduced. Further, in the configuration in which hydrogen is supplied to the hydrogen engine, the amount of spare hydrogen consumed is reduced.

  Next, a modified example of the poisoning detection means will be described.

  In the above embodiment, the temperature sensor 36 is used as the poisoning detection means. Instead, a flow rate sensor (not shown) for detecting the flow rate of the gas discharged from the reformed gas outlet 14B of the reforming unit 14 is used. Can be used. That is, as shown in FIG. 5B, when the sulfur poisoning amount of the reforming catalyst 18 is increased, the number of moles of the product gas represented by the formulas (1) and (2) is increased with respect to the number of moles of the raw material gas. It is known that the flow rate F of the gas discharged from the reformed gas outlet 14B decreases because the quality reaction stagnates. Therefore, the catalyst regeneration controller 34 determines that the regeneration condition in step S10 is not satisfied when the flow rate F is equal to or greater than the threshold value F0, and determines that the regeneration condition is satisfied when the flow rate F is less than the threshold value F0.

  In the configuration in which the operating conditions of the hydrogen generator 10 (the amount of reforming material supplied to the reforming unit 14 and the amount of heat supplied from the heating unit 16) vary, the reforming material (and steam introduced into the reforming unit 14). It is preferable to provide a flow rate sensor for detecting the flow rate of the mixed gas with the flow rate of the reformed gas and the ratio of the flow rate of the exhaust gas from the reformed gas outlet 14B to the flow rate of the reforming raw material. The flow rate sensor for the exhaust gas from the reforming unit 14 is preferably provided in the hydrogen supply line 22, and the flow rate sensor for the introduced gas to the reforming unit 14 is preferably provided in the raw material supply line 20.

  Further, instead of the temperature sensor 36, a gas concentration sensor (not shown) that detects the flow rate of the gas discharged from the reformed gas outlet 14B of the reforming unit 14 can be used. That is, as shown in FIG. 5C, when the sulfur poisoning amount of the reforming catalyst 18 increases, the reforming reaction stagnates, so that the reformed product in the gas discharged from the reformed gas outlet 14B. It is known that the concentration of hydrogen and carbon monoxide, which is, decreases, and the concentration of hydrocarbon, which is a reforming raw material, increases. By providing a gas concentration sensor that detects the concentration of the specific component in the gas discharged from the reformed gas outlet 14B, a signal corresponding to the poisoning status of the reforming catalyst 18 can be obtained.

  For example, when a gas concentration sensor that detects the concentration of hydrogen or carbon monoxide is used, the catalyst regeneration controller 34 determines that the regeneration condition in step S10 is not satisfied when the gas concentration C is equal to or greater than the threshold value C0. When the gas concentration C is lower than the threshold value C0, it is determined that the regeneration condition is satisfied. A gas concentration sensor that detects the concentration of the outlet gas from the reforming unit 14 is preferably provided in the hydrogen supply line 22.

  Thus, in the hydrogen generator 10, various sensors can be used to detect (monitor) the poisoning status of the reforming catalyst 18. A plurality of types of sensors may be provided, and the poisoning status of the reforming catalyst 18 may be detected based on these output signals.

  In the above embodiment, an example in which the regeneration switching device and the raw material switching device are mainly configured by the regeneration gas supply line 28 and the valves V1 to V4 has been shown, but the present invention is not limited to this, and various configurations are possible. These regeneration switching devices and raw material switching devices can be used. In addition, when the hydrogen consuming apparatus 12 is configured to allow the introduction of the sulfur component, the regeneration gas discharge line 32 and the valves V5 and V6 can be eliminated.

  In the above embodiment, an example in which the manual regeneration switch 38 is forcibly switched to the regeneration mode has been described. However, the present invention is not limited to this, and for example, forced mode switching may be eliminated. Automatic switching according to other conditions (for example, interlocking with idling stop) may be performed. Conversely, the regeneration mode may be selected only by manual operation using the manual regeneration switch 38 or the like.

  Furthermore, in the said embodiment, although the hydrogen production | generation apparatus 10 was provided with the manual regeneration switch 38 for forcibly switching from operation mode to regeneration mode, it was not limited to this. For example, instead of or together with the manual regeneration switch 38, a manual switch (forced switching means) for forcibly switching from the regeneration mode to the operation mode or forcibly maintaining the operation mode is provided. be able to. According to this configuration, for example, when it is necessary to generate hydrogen in the reforming unit 14 or when the reforming unit 14 has not reached a predetermined temperature, such as when the hydrogen generator 10 is started, the mode is changed to the regeneration mode. Therefore, the reformed fuel can be effectively used for hydrogen generation and start-up characteristics can be improved.

1 is a system flow diagram showing a schematic overall configuration of a fuel cell system according to an embodiment of the present invention. It is a flowchart which shows the mode switching control flow of the driving | operation and regeneration by the catalyst regeneration controller which comprises the fuel cell system which concerns on embodiment of this invention. It is a schematic diagram of this fuel cell. It is a system flow figure of the operation mode selection state of the fuel cell system concerning the embodiment of the present invention. It is a system flow figure of the regeneration mode selection state of the fuel cell system concerning the embodiment of the present invention. FIG. 3 is a diagram for explaining thresholds for switching between operation and regeneration modes in the fuel cell system according to the embodiment of the present invention, where (A) is a diagram when a temperature detection sensor is used, and (B) is a flow rate sensor. (C) is a diagram when a gas concentration sensor is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydrogen generator 14 Reforming part 16 Heating part 18 Reforming catalyst 26 Combustion exhaust gas line (discharge pipe)
28 Regeneration gas supply line (regeneration piping)
30 Sulfur trap (sulfur removal part)
34 Catalyst regeneration controller (control device)
36 Temperature sensor (poison detection means)
38 Manual regeneration switch (Forced switching means)
V4 valve

Claims (9)

A reforming unit in which a reforming reaction for generating a hydrogen-containing gas from a reforming raw material containing a sulfur component is performed using a supported reforming catalyst;
A heating unit disposed adjacent to the reforming unit and heating the reforming unit so that the reforming reaction proceeds in the reforming unit by burning the supplied fuel;
Catalyst regeneration means for performing a regeneration step for recovering the activity of the reforming catalyst by supplying water vapor in the combustion exhaust gas of the heating unit to the reforming unit in a predetermined case;
A hydrogen generation apparatus comprising:   The hydrogen generation apparatus according to claim 1, wherein the catalyst regeneration unit includes a sulfur removal unit for removing sulfur components in the combustion exhaust gas. The catalyst regeneration means includes
Poisoning detection means for outputting a signal corresponding to the sulfur poisoning status of the reforming catalyst;
A regeneration switching device capable of switching between a state of discharging the combustion exhaust gas of the heating unit out of the system and a state of leading to the reforming unit;
A raw material switching device capable of switching between a state in which the reforming raw material is supplied to the reformer from a supply path for supplying the reforming raw material to the reformer and a state in which the raw material supply to the reformer is stopped When,
When it is determined that the activity of the reforming catalyst is lower than a set value based on the output signal of the poisoning detection means, the raw material switching device is switched to the raw material supply stop side of the reformer, and the A control device for switching the regeneration switching device to the introduction side of the combustion exhaust gas to the reformer;
The hydrogen generator of Claim 1 or Claim 2 comprised including these.   The hydrogen generation apparatus according to claim 3, wherein the poisoning detection unit includes a temperature detector that outputs a signal corresponding to a temperature of the reforming catalyst.   The hydrogen generation apparatus according to claim 3 or 4, wherein the poisoning detection means includes a flow rate detector that outputs a signal corresponding to a flow rate of the gas discharged from the reforming unit.   The hydrogen generation apparatus according to claim 3, wherein the poisoning detection unit includes a gas concentration detector that outputs a signal corresponding to the concentration of gas discharged from the reforming unit.   The regeneration switching device includes a valve that is provided in a regeneration pipe that branches from an exhaust pipe that leads the combustion exhaust gas from the heating unit to the outside of the system and guides the combustion exhaust gas to the reforming part, and that can open and close the regeneration pipe. The hydrogen generator according to any one of claims 3 to 6, comprising:   Forcing the control device to operate so as to switch the raw material switching device to the raw material supply stop side of the reformer and to switch the regeneration switching device to the combustion exhaust gas introduction side to the reformer The hydrogen generator according to any one of claims 3 to 7, further comprising a switching unit.   Forcibly switching means for forcibly operating the control device so as to switch the raw material switching device to the raw material supply side of the reformer and to switch the regeneration switching device to the exhaust gas exhaust side. The hydrogen generator according to any one of claims 3 to 8, which is provided.