JP2006102597A - Method for regenerating sulfur-poisoned catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for regenerating a sulfur-poisoned catalyst, by which the sulfur-poisoned catalyst can be regenerated efficiently at a low temperature in a short time, a cycle of regeneration of the sulfur-poisoned catalyst can be prolonged and the sulfur-poisoned catalyst can be prevented from being deteriorated thermally and the energy loss can be reduced when the sulfur-poisoned catalyst is regenerated. <P>SOLUTION: An alumina-deposited rhodium catalyst 10 sulfur-poisoned in a fuel reformation reaction is regenerated by supplying steam of a concentration higher than that of the steam in the reactive gas used in the reformation reaction to the alumina-deposited rhodium catalyst together with air at high temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for regenerating a sulfur poisoning catalyst that reduces and regenerates the degree of poisoning of a catalyst poisoned with a sulfur component accompanying a catalytic reaction.

Pt, Rh, metal catalysts typified by a noble metal such as Pd, the reforming reaction and the fuel, for example, widely used in such harmful components (NO _x, etc.) to clean the reduction in the exhaust gas discharged from an internal combustion engine Has been.

In the reforming reaction of fuel, for example, by supplying steam to hydrocarbons (C _n H _m ) in which the fuel components are desulfurized and the sulfur content is reduced to the ppm order (for example, about 0.1 ppm), synthesis gas (H ₂ + CO) is produced. However, although the hydrocarbons in the reaction gas are once desulfurized, the gas still contains a small amount of sulfur, and the metal catalyst for fuel reforming is poisoned by this sulfur and the catalytic activity is low. It decreases remarkably with time [SO ₂ , H ₂ S (gas phase) + catalytic active site → S-catalytic active site (reaction site clogging by S)], and it is difficult to maintain the initial catalytic activity for a long time. .

  Further, for example, exhaust gas discharged from an automobile engine is generally harmless in a vehicle by a purification catalyst (for example, a three-way catalyst) for purifying harmful components such as hydrocarbons and nitrogen oxides contained in the gas. After being purified by carbon dioxide, water, nitrogen, etc., it is discharged outside the vehicle. However, the three-way catalyst or the like is also similar to the above in that the catalytic activity is remarkably lowered with an increase in the reaction time, and it is difficult to maintain the durability performance that maintains the initial catalytic activity for a long period of time.

  In particular, the steam reforming reaction having a slow reaction rate as described above is remarkably affected by catalyst deterioration, so that the steam reactivity is remarkably lowered even by sulfur poisoning at a level where there has been no problem.

  Therefore, in order to maintain the initial activity of the catalyst, when the catalyst activity is reduced due to sulfur poisoning, a process for removing sulfur molecules adsorbed on the catalyst by some means and regenerating to a state with high catalyst activity is required. .

  As a method for regenerating a catalyst poisoned with sulfur, conventionally, a rich gas containing a reducing agent such as hydrogen is introduced in a high temperature environment, and the adsorbed sulfur content is desorbed as the catalyst temperature rapidly increases. Alternatively, a method of reducing and removing the adsorbed sulfur component by a chemical reaction with a reducing agent has been performed (see, for example, Patent Document 1). Also known is a method of recovering the catalytic activity by introducing water vapor into the poisoned catalyst at a high temperature.

  However, in terms of regeneration of the catalyst activity, it is not always sufficient to recover the activity, and in particular, it is insufficient for the sulfur poisoned catalyst poisoned by the steam reforming reaction. In order to sufficiently recover the catalytic activity of the sulfur-poisoned catalyst as described above, it takes a long time or the regeneration temperature becomes high, and the catalyst deterioration due to the influence of heat is inevitable.

In addition, if a three-way catalyst that purifies exhaust gas discharged from an internal combustion engine such as an engine mounted on an automobile is deactivated in a short period of time, the amount of harmful components such as nitrogen oxides released into the atmosphere The increase in the environment is a concern, and it will worsen the global environment.
JP 2002-161781 A

  As described above, there are several methods for the regeneration of sulfur-poisoned catalysts that have been poisoned with sulfur so far. Establishing a technology that can not sufficiently recover the deterioration of the catalyst activity that accompanies it, or that it takes a long time to recover, or that the catalyst itself deteriorates, and that the catalyst activity can be efficiently regenerated after poisoning. It was sought after.

  The present invention has been made in view of the above, and can efficiently regenerate a sulfur-poisoned catalyst poisoned with sulfur at a low temperature in a short time, and effectively reduce energy loss associated with the regeneration. An object of the present invention is to provide a method for regenerating a sulfur poisoning catalyst capable of achieving the above object, and to achieve the object.

  The present invention has obtained the knowledge that increasing the water vapor concentration in the regeneration atmosphere of the poisoned catalyst poisoned with sulfur is effective for desorption of sulfur from the poisoned catalyst, that is, regeneration of the catalytic activity, This is based on this finding. Specific means for achieving the above object are as follows.

  In order to achieve the above object, the sulfur poisoning catalyst regeneration method of the present invention supplies a high concentration of water vapor to the sulfur poisoned poison catalyst at a high temperature than the water vapor concentration in the atmosphere at the time of poisoning. Thus, the poisoning catalyst is regenerated.

In the present invention, when steam is introduced into a sulfur-poisoned catalyst at a high temperature for regeneration, the water vapor concentration in the introduced component introduced at the time of regeneration occupies the atmosphere component at the time of the catalyst reaction subjected to sulfur poisoning. By making the concentration higher than the water vapor concentration, the desorption reaction of sulfur (S) from the sulfur poisoned catalyst [catalyst regeneration reaction; S-catalyst active site → H ₂ S (gas phase) + catalytic active site (S Desorption))] can be promoted by the H ₂ O component, so that the regeneration speed is greatly improved, the time required for regeneration can be shortened, the regeneration cycle can be prolonged, and the regeneration temperature can be lowered, Energy loss generated in the regeneration process can be greatly reduced, and catalyst deterioration caused by heat during regeneration can be significantly suppressed as compared to the conventional case where regeneration is performed at a high temperature for a long time.

As a preferred example, steam is imparted to hydrocarbons extracted from fuels such as petroleum (in the present invention, a mixed gas that is subjected to fuel reforming reaction by imparting steam to hydrocarbons is referred to as “reaction gas”). ) When the fuel reforming catalyst that obtains hydrogen by steam reforming regenerates the poisoned catalyst that was poisoned with a small amount of sulfur in the reaction gas, the catalyst in the reaction gas supplied to the catalyst during steam reforming It is effective to supply and regenerate the water vapor concentration, that is, the water vapor concentration higher than the water vapor concentration in the reaction gas atmosphere in which the hydrocarbon (C _n H _m ) gas and the water vapor necessary for reforming are mixed. is there. As a result, as described above, the reproduction speed is greatly improved, and the time required for reproduction can be shortened, the reproduction cycle can be prolonged, and the reproduction temperature can be lowered.

In addition, when the purification catalyst that purifies organic components (NO _x etc.) in the exhaust gas discharged from the internal combustion engine regenerates the poisoned catalyst poisoned with a small amount of sulfur in the exhaust gas, It is effective to supply water vapor with a concentration higher than the water vapor concentration of the water, so that, as described above, the regeneration speed is greatly improved, the time required for regeneration is shortened, and the regeneration cycle is reduced. Prolongation and lowering of the regeneration temperature are possible.

  In the method for regenerating a sulfur poisoning catalyst of the present invention, it is effective to supply steam under a high temperature condition of 200 ° C. or higher than the temperature at the time of poisoning. For example, in the case of regeneration of a poisoned catalyst sulfur-poisoned by steam reforming, it is preferable to carry out at a temperature of 800 ° C. or higher. The temperature at the time of water vapor supply may depend on the regeneration conditions (such as the water vapor concentration of the system) at the time of regeneration, but the regeneration speed is improved by providing a temperature difference of 200 ° C or more from the temperature at the time of poisoning. However, catalyst deterioration is suppressed, the time required for regeneration is shortened and the regeneration cycle is lengthened, and energy loss caused by regeneration can be greatly reduced.

  According to the present invention, a sulfur poisoning catalyst capable of efficiently regenerating a sulfur poisoning catalyst poisoned with sulfur at a low temperature in a short time and effectively reducing energy loss accompanying regeneration. A reproduction method can be provided. In addition, the regeneration cycle can be extended, and the decrease in catalyst activity due to thermal degradation due to the lowering of the regeneration temperature can be greatly reduced.

  An embodiment of the method for regenerating a sulfur poisoning catalyst of the present invention will be described with reference to FIGS. In the present embodiment, a reforming reaction is performed by supplying a reaction gas necessary for a fuel reforming reaction to a fuel reforming catalyst, and a pulse is applied to a reaction gas supply path based on a change in the concentration of hydrogen produced by reforming. In particular, the regeneration is performed by adding water and air necessary for regeneration.

  As shown in FIG. 1, the present embodiment is attached to an alumina-supported rhodium catalyst 10 (fuel reforming catalyst), a gas supply pipe 20 for supplying gas to the alumina-supported rhodium catalyst, and the gas supply pipe 20. Regeneration of an alumina-supported rhodium catalyst that has been poisoned with sulfur in the reforming reaction without stopping the supply of the reaction gas for fuel reforming using the reactor equipped with the injector 30 (catalyst regeneration reaction) It is configured to be able to perform.

The fuel reforming reaction in this embodiment uses isooctane (C ₈ H ₁₈ ) as the hydrocarbon component of the fuel reforming reaction gas, and isooctane is 5 ppms (weight concentration of sulfur in isooctane; the same applies hereinafter). It can be supplied with steam and can be carried out at a reforming temperature of -700 ° C., and the alumina-supported rhodium catalyst is poisoned over time with a small amount of sulfur contained in isooctane. The water vapor concentration at this time was 45% with respect to 3% of isooctane.

The alumina-supported rhodium catalyst 10 uses alumina (Al ₂ O ₃ ) as a carrier and supports rhodium (Rh) particles thereon, and reforms the supplied isooctane to carbon monoxide and hydrogen. [C ₈ H ₁₈ + 8H ₂ O → 8CO + 17H ₂ ]. A temperature sensor 70 for measuring the catalyst temperature is attached in the vicinity of the alumina-supported rhodium catalyst 10.

  The heater 60 is provided so that the alumina-supported rhodium catalyst 10 can be heated, and the alumina-supported rhodium catalyst 10 can be controlled to a temperature necessary for the fuel reforming reaction and the catalyst regeneration reaction. As the heater, an electric heater, a heating device that heats with combustion heat obtained by burning hydrocarbons, or the like can be used.

  One end of the gas supply pipe 20 communicates with the alumina-supported rhodium catalyst 10, and the other end is connected to a fuel supply source (not shown), and a reaction gas for performing a fuel reforming reaction, that is, isooctane and air. (Air) and water vapor (steam) can be mixed and supplied.

  The injector 30 is attached to the gas supply pipe 20 upstream of the alumina-supported rhodium catalyst 10 in the gas insertion direction, and water and air (air) necessary for regeneration are mixed into a mist to form a gas supply pipe. The gas can be supplied directly in addition to the reaction gas inserted through the inside 20. One end of a supply pipe 40 through which water and air (air) used for regeneration are inserted is connected to the injector 30, and the other end is connected to a water and air supply source (not shown).

  The supply of water and air can be appropriately selected from an injection device that can be sprayed in the form of a mist or a shower, in addition to the above-described injector, and may be supplied in the state of steam by heating in advance.

  A gas discharge pipe 50 is provided on the opposite side of the alumina-supported rhodium catalyst 10 to the gas supply pipe 20 and communicates with the alumina-supported rhodium catalyst 10 so that the atmosphere after the reaction can be discharged.

  A hydrogen sensor 80 for measuring the hydrogen concentration in the gas atmosphere after fuel reforming is attached to the gas exhaust pipe 50, and sulfur poisoning of the alumina-supported rhodium catalyst from the hydrogen concentration generated in the fuel reforming reaction. It is now possible to detect catalyst deterioration due to.

  The injector 30, the heater 60, and the like are electrically connected to a control device (not shown) so that the alumina-supported rhodium catalyst that has been poisoned along with fuel reforming can be regenerated by receiving a signal from the control device. Yes. Hereinafter, in the present embodiment, the regeneration control when the fuel reforming reaction is performed will be specifically described with reference to FIG.

From the fuel supply source, an isooctane mixed gas [mixed gas of isooctane, air, and water vapor (reforming steam concentration d ¹ = 45%)], which is a reforming fuel, passes through the gas supply pipe 20 shown in FIG. When supplied to the alumina-supported rhodium catalyst 10 heated to about 700 ° C., the reforming reaction proceeds on the alumina-supported rhodium catalyst 10, and hydrogen is produced together with carbon monoxide (the hydrogen concentration at the start of the reaction is 42). 7%; see Figure 2). Thereafter, when the fuel reforming reaction was continued, as shown in FIG. 2, the hydrogen concentration gradually decreased with the passage of time. This is due to the fact that the alumina-supported rhodium catalyst 10 was poisoned by the sulfur content present on the ppm order in the isooctane mixed gas, and the catalytic activity was lowered. Therefore, when 28 minutes have passed since the start of the reforming reaction (point t ^a ), the regeneration process was performed as follows.

In the regeneration process, while supplying the isooctane mixed gas, water and air are simultaneously gas-liquid mixed from the injector 30 to the gas supply pipe 20 and injected for 3 seconds, and in the mixed atmosphere of the injected isooctane mixed gas, water and air The steam concentration (regeneration steam concentration d ² ) was made to be the same as the reforming steam concentration d ¹ . That, steam ratio d ² / d ¹ represented by steam concentration d ² / steam concentration d ¹ is 1.

  The water jetted from the injector 30 is atomized and mixed with air, and is vaporized by the heat of the heating catalyst (in this embodiment, the catalyst temperature is 900 ° C.) to become water vapor. The water vapor concentration to which the catalyst 10 is exposed can be controlled. In addition, air is supplied together with water from the injector, oxygen in the air burns and the temperature rapidly rises, promoting the vaporization of water and the temperature rise of the catalyst, and instantaneously increasing the steam partial pressure. it can.

However, under the regeneration conditions with the steam ratio d ² / d ¹ = 1, the catalytic activity of the sulfur-poored alumina-supported rhodium catalyst 10 is not regenerated, but deteriorates continuously, as shown in FIG. The concentration further decreased.

Subsequently, when 36 minutes have elapsed from the start of the reforming reaction (point t ^b ), while supplying the isooctane mixed gas again, water and air are simultaneously gas-liquid mixed from the injector 30 and fed into the gas supply pipe 20 for 3 seconds. Jetted. At this time, the water vapor concentration (regeneration steam concentration d ³ ) in the mixed atmosphere of the isooctane mixed gas after injection and water and air was set to 1.7 times the steam concentration d ¹ during reforming ( That is, the steam ratio d ³ / d ¹ = 1.7) expressed by the steam concentration d ³ / steam concentration d ¹ . The catalyst temperature is 900 ° C. After the regeneration treatment, as shown in FIG. 2, the hydrogen concentration is almost restored to the start of the reforming reaction, and the catalytic activity of the alumina-supported rhodium catalyst 10 is regenerated at a temperature that does not cause thermal degradation of the catalyst in a short time. In addition, the energy loss associated with regeneration could be significantly reduced compared to the prior art.

  In the present embodiment, the temperature of the alumina-supported rhodium catalyst 10 at the time of regeneration is set to 900 ° C. which is 200 ° C. higher than the temperature at the time of steam reforming. It is desirable to suppress catalyst deterioration. The temperature range at the time of regeneration is preferably as high as possible within a range in which energy loss is suppressed and catalyst deterioration is not caused. Considering that the catalyst activity is recovered in a short time while further increasing the regeneration rate, the steam reforming temperature +200 It is preferable that the temperature is not lower than ° C.

Then, when the fuel reforming reaction is continued, the hydrogen concentration decreases with time as shown in FIG. 2, and reaches 57 minutes and 62 minutes from the start of the reforming reaction (point t ^c , At the point t ^d ), the steam concentration (regeneration steam concentration d ⁴ ) in the mixed atmosphere of the isooctane mixed gas, water and air after injection from the injector 30 is 1.3 of the reforming steam concentration d ¹ . Water and air were mixed in the gas supply pipe 20 and injected for 3 seconds so as to be double (steam ratio d ⁴ / d ¹ = 1.3). However, the catalytic activity of the alumina-supported rhodium catalyst 10 could not be recovered under the steam ratio d ⁴ / d ¹ = 1.3. The catalyst temperature is 900 ° C.

Subsequently, when 70 minutes have elapsed from the start of the reforming reaction (point t ^e ), water and air are mixed from the injector 30 with a steam ratio (d ⁵ / d ¹ ) = 1.7 as described above. Then, when the gas was injected into the gas supply pipe 20 for 3 seconds, the catalytic activity of the alumina-supported rhodium catalyst 10 could be recovered almost to the start of the reforming reaction as described above.

Similarly, since the hydrogen concentration decreased with the lapse of time for performing the fuel reforming reaction, 90 minutes have elapsed from the start of the reforming reaction (point t ^f ), and this time, the isooctane mixed gas after the injection from the injector 30 and The water vapor concentration in the mixed atmosphere of water and air (regeneration steam concentration d ⁶ ) is 1.5 times the reforming steam concentration d ¹ (steam ratio d ⁶ / d ¹ = 1.5). a manner, the gas supply pipe 20, water and air to the gas-liquid mixture to injection a few seconds, (t ^g that has passed 98 minutes from the start of the reforming reaction) followed after performing several minutes fuel reforming reaction, Again, water and air were mixed into the gas supply pipe 20 at a steam ratio (d ⁷ / d ¹ ) = 1.5 and injected for several seconds. The catalyst temperature at this time is also 900 degreeC. As shown in FIG. 2, when the steam ratio is 1.5, the catalytic activity of the alumina-supported rhodium catalyst 10 is recovered in a short time, and the energy loss due to regeneration is greatly reduced while suppressing thermal deterioration of the catalyst. I was able to.

  Further, after that, when the regeneration process at the same steam ratio (= 1.7) is repeated, the same recovery effect is reproduced, and every 20 to 30 minutes in the fuel reforming reaction process as in this embodiment. By adding a regeneration process of several seconds to 3 seconds about once every two times, it becomes possible to continuously perform a good fuel reforming reaction while keeping the time load for regeneration short. The injection interval (pulse interval) from the injector 30 is not limited to the above, and may be appropriately selected.

  FIG. 3 shows the poisoning recovery rate (%) of the alumina-supported rhodium catalyst 10 in the regeneration process performed by changing the steam ratio as described above. In this embodiment, as shown in FIG. 3, when the ratio of the steam concentration during regeneration / the steam concentration during reforming (during poisoning) (steam ratio) exceeds 1.3, that is, the reaction during fuel reforming When regeneration processing is performed by supplying high-concentration water vapor (water) that is 1.3 times higher than the water vapor concentration in the gas, the regeneration effect is dramatically improved, and the regeneration efficiency is increased by further increasing the steam ratio. We were able to raise more.

  In the present invention, for example, when the water vapor concentration in the reaction gas at the time of steam reforming is about 30% to 50%, the reforming reaction gas in which steam is imparted to hydrocarbons, water necessary for regeneration, and The water vapor concentration in the atmosphere mixed with air is preferably 60% to 90%.

  As described above, by simultaneously supplying water and air in a pulsed manner during regeneration, the temperature of the catalyst can be raised using oxidation heat generated by the increase of air (ie, oxygen), and the vaporization of water is promoted. It is possible to increase the steam partial pressure in the atmosphere in contact with the alumina-supported rhodium catalyst during regeneration, thereby efficiently regenerating the sulfur-supported rhodium catalyst poisoned in a short time, and catalytic activity Can be effectively recovered.

In the above embodiment, isooctane is used as the hydrocarbon component that is the reformed fuel. However, hydrocarbons other than isooctane (C _n H _m ; for example, methane, butane, etc.) can be used without particular limitation. The same applies when other hydrocarbons are used.

  In the above, in order to increase the water vapor concentration during the regeneration reaction, water and air are mixed with gas and liquid and supplied. However, for example, in a reaction environment where the catalyst heating temperature and water vaporization sufficiently proceed, It is also possible to supply only (in the form of mist) or supply in the form of water vapor.

  In the above embodiment, water and air necessary for regeneration are added in a pulsed manner to the process of performing the fuel reforming reaction without stopping the supply of the reaction gas necessary for the fuel reforming reaction. In the middle of the reforming reaction, the regeneration process is performed, and the continuous process of returning to the reforming reaction immediately after the completion of the regeneration is performed. However, the present invention is not limited to this. You can also do it. For example, in addition to the gas supply pipe 20 for supplying the reaction gas, a supply pipe for supplying water or water vapor necessary for regeneration or water and air (especially oxygen) is further provided so as to communicate with the catalyst. After stopping the supply of the reaction gas for quality, the operation of supplying water etc. directly on the catalyst and regenerating it may be repeated.

  Further, as described above, the regeneration can be performed periodically or as necessary, in addition to monitoring the amount of decrease in the hydrogen concentration generated by the fuel reforming reaction.

In addition to the above-described embodiment in which the fuel reforming reaction is performed, a purification catalyst for purifying exhaust gas discharged from an internal combustion engine such as a gasoline engine or a diesel engine (for example, oxidizing HC and CO and changing NO _x to nitrogen and oxygen) In the case of an embodiment in which regeneration is performed by using a three-way catalyst that performs reduction and supplying a water vapor having a concentration higher than the water vapor concentration contained in the exhaust gas to the purification catalyst, the same operation as in the above embodiment should be performed. Can do.

Specifically, as in FIG. 1, for example, a three-way catalyst (10) is provided inside the exhaust pipe (20) downstream of the exhaust pipe (20) connected at one end to an internal combustion engine such as a gasoline engine or a diesel engine. When the exhaust gas discharged from the internal combustion engine is inserted into the exhaust pipe (20) and the three-way catalyst (10) is used to purify organic components [NO _{x and the} like] in the exhaust gas, By providing an injector (30) for gas-liquid mixing of water and air (Air) in the form of a mist in the same way as in FIG. 1, on the upstream side in the gas insertion direction of the three way catalyst provided in the exhaust pipe, The three-way catalyst poisoned with sulfur can be regenerated in the same manner as in the above embodiment. The three-way catalyst can be provided inside a muffler attached to the other end of the exhaust pipe, for example. The three-way catalyst can be heated with or without the heater 60 shown in FIG. 1 and heated with the heat of exhaust gas (exhaust heat) from the internal combustion engine.

The regeneration process of the three-way catalyst poisoned with sulfur by purifying the exhaust gas is similar to the regeneration control in the case of performing the fuel reforming reaction in the above embodiment, and the engine is operated and the exhaust pipe is pulsed. Regeneration can be performed by adding water and air necessary for regeneration. In this case, in addition to supplying water and air by gas-liquid mixing, it is also possible to supply only water (in the form of a mist) or supply it as steam with exhaust heat in advance.
The water vapor concentration in the exhaust gas is usually about 10%, and the water vapor concentration in the atmosphere during regeneration is preferably 20% to 40%.

  In addition to performing regeneration by adding water, air, etc. in a pulsed manner when the engine is operating, for example, switching to regeneration processing is performed after the engine is stopped. For example, it is necessary for regeneration separately from the exhaust pipe connected to the internal combustion engine. A supply pipe for supplying water or water vapor, or water and air (especially oxygen) is further provided in communication with the three-way catalyst, and water is directly supplied onto the three-way catalyst for regeneration after the engine is stopped. May be.

For regeneration, a NO _x sensor is attached in place of the hydrogen sensor 80 on the further downstream side of the three-way catalyst in the gas insertion direction of the exhaust pipe, and the amount of NO _x in the exhaust gas discharged after purification is reduced. detection, monitoring to e.g. _the amount of NO _x, it is determined whether it exceeds a predetermined value, can be performed when the amount of NO _x is determined to exceed a predetermined value, more regularly Alternatively, reproduction may be performed as necessary.

It is a rough section lineblock diagram showing the reaction device concerning the embodiment of the present invention. It is a graph for demonstrating the fall of catalyst activity, and the recovery effect of the catalyst activity by reproduction | regeneration with time. It is a graph which shows the relationship between steam concentration ratio (steam density at the time of reproduction / steam density at the time of poisoning) and poisoning recovery rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Rhodium catalyst supported on alumina 20 ... Gas supply pipe 30 ... Injector

Claims (4)

  A method for regenerating a sulfur poisoning catalyst, wherein the poisoning catalyst poisoned with sulfur is supplied at a high temperature with water vapor having a concentration higher than that in the atmosphere at the time of poisoning to regenerate the poisoning catalyst.   The poisoning catalyst is a fuel reforming catalyst that obtains hydrogen by steam reforming the fuel, and regenerates by supplying steam having a concentration higher than the steam concentration in the reaction gas during the steam reforming. The method for regenerating a sulfur poisoning catalyst according to claim 1.   2. The purification catalyst according to claim 1, wherein the poisoning catalyst is a purification catalyst that purifies exhaust gas discharged from an internal combustion engine, and is regenerated by supplying water vapor having a concentration higher than the water vapor concentration in the exhaust gas. Of regenerating sulfur poisoning catalyst.   The method for regenerating a sulfur poisoning catalyst according to any one of claims 1 to 3, wherein the supply is performed at a temperature of "temperature at poisoning + 200 ° C" or higher.

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