JP2021095300A - Ammonia-reforming type hydrogen supply device and ammonia-reforming type hydrogen supply method using the same - Google Patents

Abstract

To provide an ammonia-reforming type hydrogen supply device capable of removing ammonia from a reformed gas containing ammonia and hydrogen at a sufficiently high removal rate and capable of sufficiently miniaturizing the device while having a sufficiently high hydrogen purification capacity.SOLUTION: An ammonia-reforming type hydrogen supply device comprises: a raw material feeder for supplying ammonia as a raw material; an ammonia reformer for reforming ammonia supplied from the raw material feeder to generate a reformed gas containing hydrogen; a hydrogen purification device having an ammonia selective oxidation catalyst for oxidizing ammonia in the reformed gas supplied from the ammonia reformer; and an oxygen feeder for supplying oxygen to the hydrogen purification device. The ammonia selective oxidation catalyst is a catalyst provided with an acidic porous carrier and at least one kind of catalyst metal selected from the group consisting of Cu and Ru carried on the acidic porous carrier.SELECTED DRAWING: None

Description

The present invention relates to an ammonia reformed hydrogen supply device and an ammonia reformed hydrogen supply method using the same.

The use of hydrogen-fueled fuel cells is attracting attention as a clean energy source that can curb environmental pollution and global warming. In recent years, various techniques related to devices and methods for supplying hydrogen to such fuel cells have been studied. For example, Japanese Patent Application Laid-Open No. 2019-53855 (Patent Document 1) describes a reformer that reforms ammonia to generate a reformed gas containing hydrogen, and adsorbs ammonia contained in the reformed gas. A device including a plurality of adsorbers having the adsorbent of the above is disclosed, and hydrogen is supplied to a fuel cell by using such a device. However, since the apparatus described in Patent Document 1 uses a plurality of adsorbents having an adsorbent for removing ammonia remaining in the reformed gas, from the viewpoint of further miniaturization of the apparatus. It wasn't always enough.

The catalyst used for oxidatively decomposing ammonia to generate hydrogen is selected from the group consisting of Ru, Co, Rh, Ir and Ni, for example, in Japanese Patent Application Laid-Open No. 2016-164109 (Patent Document 2). Ammonia oxidative decomposition catalyst having one or more kinds of catalyst metals and a zeolite carrier carrying the catalyst metal is disclosed. However, the ammonia oxidative decomposition catalyst described in Patent Document 2 is only known to be used for decomposing ammonia in an environment in which hydrogen does not exist (in a hydrogen-free environment).

Japanese Unexamined Patent Publication No. 2019-53855 Japanese Unexamined Patent Publication No. 2016-164109

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to remove ammonia from a reformed gas containing ammonia and hydrogen at a sufficiently high removal rate, and the hydrogen purification ability is sufficiently high. It is an object of the present invention to provide an ammonia-modified hydrogen supply device capable of sufficiently downsizing the device while having the above-mentioned equipment, and an ammonia-modified hydrogen supply method using the device.

As a result of diligent research to achieve the above object, the present inventors supply an ammonia-modified hydrogen supply device from a raw material feeder for supplying ammonia as a raw material and the raw material supply device. An ammonia reformer for producing a reforming gas containing hydrogen by reforming ammonia and an ammonia selective oxidation catalyst for oxidizing ammonia in the reforming gas supplied from the ammonia reformer. A hydrogen purification device including the hydrogen purification device and an oxygen supply device for supplying oxygen to the hydrogen purification device are provided, and further, the ammonia selective oxidation catalyst is supported on an acidic porous carrier and the acidic porous carrier. Ammonia is removed from a reformed gas containing ammonia and hydrogen at a sufficiently high removal rate by using a catalyst having at least one catalyst metal (metal active point of the catalyst) selected from the group consisting of Cu and Ru. It has been found that it is possible to sufficiently miniaturize the apparatus while having a sufficiently high hydrogen purification capacity, and the present invention has been completed.

That is, the ammonia reformed hydrogen supply device of the present invention
A raw material feeder for supplying ammonia as a raw material,
An ammonia reformer for producing a reformed gas containing hydrogen by reforming the ammonia supplied from the raw material feeder, and
A hydrogen purification apparatus provided with an ammonia selective oxidation catalyst for oxidizing ammonia in the reforming gas supplied from the reformer.
An oxygen supply device for supplying oxygen to the hydrogen purification device and
And also
The ammonia selective oxidation catalyst is a catalyst comprising an acidic porous carrier and at least one catalyst metal selected from the group consisting of Cu and Ru supported on the acidic porous carrier. It is a thing.

In the ammonia-modified hydrogen supply device of the present invention, it is preferable that the acidic porous carrier is zeolite.

Further, in the ammonia-modified hydrogen supply method of the present invention, the ammonia as a raw material is supplied from the raw material supply device to the ammonia reformer by using the ammonia-modified hydrogen supply device of the present invention. After generating the quality gas, the reforming gas and the reforming gas are supplied by supplying oxygen from the oxygen supply device to the hydrogen purification device while supplying the reforming gas from the ammonia reformer to the hydrogen purification device. This method is characterized in that hydrogen is purified by bringing oxygen into contact with the ammonia selective oxidation catalyst and oxidizing the ammonia in the reforming gas, and the purified hydrogen is supplied.

Further, in the ammonia-modified hydrogen supply method of the present invention, the temperature of the contact gas when the reformed gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst is preferably 350 ° C. to 750 ° C.

Further, in the ammonia-modified hydrogen supply method of the present invention, the supply ratio of oxygen and ammonia at the time of contact with the ammonia selective oxidation catalyst is the volume ratio ([oxygen (O ₂ )] / [ammonia (NH ₃ )). ]) Is preferably 0.75 to 20.

Although the reason why the above object is achieved by the present invention is not always clear, the present inventors infer as follows. That is, first, as described in Patent Document 1, when a reformed gas is generated by reforming ammonia in a reformer, the reformed gas obtained is basically excess hydrogen in terms of volume ratio. And, it is considered that it contains a trace amount of ammonia (NH _{3) remaining without reforming.} When such a reformed gas is generated and ammonia is removed by using an adsorbent as described in Patent Document 1, it is basically necessary to use a large amount of the adsorbent. It becomes. In general, the adsorbent is bulky, and the amount used is proportional to the amount of the substance (ammonia) to be adsorbed. Further, a general adsorbent has a property of competitively adsorbing water and ammonia under the condition that water coexists. Therefore, it is necessary to use a larger amount of adsorbent in order to sufficiently adsorb ammonia under the condition that water coexists. Further, in the case of removing ammonia by using the adsorbent, it is necessary to regenerate or replace the adsorbent when the adsorption of ammonia to the adsorbent is saturated. In Patent Document 1, a plurality of adsorbers are used from the viewpoint of regeneration and the like. Considering the general characteristics of such an adsorbent, in the conventional apparatus as described in Patent Document 1, the apparatus uses the adsorbent to maintain the removal rate of ammonia at a sufficiently high level. It is considered that there is a limit to further miniaturization of. Then, in the field of ammonia reforming hydrogen supply equipment, the emergence of equipment capable of further miniaturization is desired.

On the other hand, as a catalyst used for decomposing ammonia to generate hydrogen, various catalysts such as the catalyst described in Patent Document 2 are known. However, conventional catalysts such as those described in Patent Document 2 are basically only recognized as being used for decomposing ammonia in a hydrogen-free environment. In fact, Patent Document 2 does not describe or suggest any technical idea of oxidizing ammonia in an environment in which ammonia, hydrogen and oxygen are present. As described above, the catalyst as described in Patent Document 2 is known as a reforming catalyst for reforming ammonia as used in the reformer described in Patent Document 1 in the first place. It's just that.

On the other hand, in the present invention, a hydrogen purification apparatus provided with an ammonia selective oxidation catalyst is used without using an adsorber of ammonia, and as such an ammonia selective oxidation catalyst, an acidic porous carrier and the acidity are used. It is possible to reduce the size of the apparatus by using a catalyst supported on a porous carrier and having at least one catalyst metal (metal active point of the catalyst) selected from the group consisting of Cu and Ru. However, it was found that ammonia can be removed from the reformed gas at a sufficiently high level. That is, as a result of diligent research to achieve the above object, the present inventors have obtained the above-mentioned catalyst (acidic porous carrier and Cu and Ru supported on the acidic porous carrier) according to the present invention. A catalyst having at least one catalytic metal (the metal active point of the catalyst) selected from the group sufficiently oxidizes (selectively oxidizes) ammonia in an environment in which ammonia, hydrogen and oxygen are present. When it is found that it has a characteristic that can be used to remove ammonia in the reforming gas, it removes ammonia from the reforming gas at a sufficiently high removal rate while reducing the size of the device. It has been found that this makes it possible to sufficiently purify hydrogen and supply purified hydrogen to the outside.

Here, in general, in an environment where ammonia, hydrogen, and oxygen are present, when an oxidation catalyst having a catalytic activity point such as a noble metal is used, the following reaction formulas 1 and 2:
(Reaction formula 1) 4NH ₃ + 3O ₂ → 2N ₂ + 6H ₂ O
(Reaction formula 2) 2H ₂ + O ₂ → 2H ₂ O
It is considered that the reaction described in the above can occur. Considering such a reaction, when a case where a gas containing ammonia, hydrogen, and oxygen is brought into contact with the oxidation catalyst is examined, in general, when hydrogen is activated in the same manner as ammonia, hydrogen Since the ignition point is lower and the minimum ignition energy is smaller, the reaction shown in reaction formula 2 (side reaction: reaction between oxygen and hydrogen) is prioritized over the reaction shown in reaction formula 1 (target reaction). It is thought to progress. Actually, when a conventional oxidation catalyst using a noble metal such as palladium (Pd) or platinum (Pt) as an active point is used, even if a gas containing ammonia, hydrogen and oxygen is brought into contact, the reaction formula 1 shows. The reaction does not proceed (see Comparative Examples 1 and 2 below). In this way, when a gas containing ammonia, hydrogen, and oxygen is brought into contact with a conventional oxidation catalyst having a catalytically active site such as a noble metal, oxygen is usually consumed in the reaction described in Reaction Scheme 2 and oxygen is consumed. It is considered that the amount of the above-mentioned reaction is insufficient and the reaction as described in the target reaction formula 1 does not proceed sufficiently. Considering the case where a mixed gas of oxygen and a reforming gas containing excess hydrogen with respect to ammonia is brought into contact with the oxidation catalyst, the hydrogen catalyst is considered to be a substance in which the reaction is more likely to proceed. It is clear that the probability of contact with is higher, and from this point of view, it is considered that the reaction described in Reaction Scheme 2 proceeds preferentially. From this point of view, conventionally, in order to remove and purify ammonia from the reformed gas containing hydrogen, it has not been proposed to oxidize and remove ammonia by using an oxidation catalyst containing a noble metal. It is presumed to be. Considering the case where oxygen is excessively introduced into the reaction system in order to sufficiently oxidize ammonia, more side reactions (reaction formula 2) occur in proportion to the amount of oxygen introduced, and hydrogen is wasted. It is clear that the supply of hydrogen will decrease as a result, and from this point of view, an oxidation catalyst is used to remove ammonia from the gas containing ammonia, hydrogen, and oxygen. It is presumed that things such as doing things have not been proposed in the past.

In this way, based on the conventional knowledge about the catalytic reaction, the reformed gas containing hydrogen, which has been produced by reforming ammonia, is brought into contact with a specific catalyst together with oxygen, and the ammonia in the reformed gas (reforming). No particular technique has been reported on the technique of oxidizing and removing (residual components of raw materials remaining untreated). However, as a result of diligent research by the present inventors, among various catalysts, when the above-mentioned specific type of ammonia selective oxidation catalyst is used, in an environment where ammonia, hydrogen and oxygen are present, It has been found that the reaction described in Reaction Scheme 1 can be sufficiently induced even with a small amount of ammonia, whereby ammonia can be oxidized and removed to efficiently purify hydrogen. , The present invention has been completed. As described above, in the present invention, by using the above-mentioned specific ammonia selective oxidation catalyst in the hydrogen purification apparatus, it is possible to remove ammonia from the reformed gas at a sufficient removal rate to purify hydrogen. Further, in the present invention, hydrogen can be sufficiently removed by using the ammonia selective oxidation catalyst without using a large amount of bulky adsorbent, so that hydrogen can be sufficiently removed in the ammonia reforming hydrogen supply device. It is possible to sufficiently reduce the size of the purification device, which makes it possible to further reduce the size of the device as compared with the conventional ammonia reforming type hydrogen supply device. Therefore, the present invention states that the ammonia-modified hydrogen supply device of the present invention can be more preferably used for applications requiring particularly miniaturization (for example, applications such as mounting on an automobile). Those guess.

According to the present invention, it is possible to remove ammonia from a reformed gas containing ammonia and hydrogen at a sufficiently high removal rate, and the device can be sufficiently miniaturized while having a sufficiently high hydrogen purification capacity. It is possible to provide an ammonia-modified hydrogen supply device capable of providing an ammonia-modified hydrogen supply device, and an ammonia-modified hydrogen supply method using the device.

It is a schematic diagram which shows one preferable embodiment of the ammonia reforming type hydrogen supply apparatus of this invention. It is a schematic diagram which shows typically the state of the reaction tube filled with a catalyst installed in the fixed bed flow type reaction apparatus used in an Example. It is a graph which shows the relationship between the heating temperature and time (minute) in the heat treatment after starting the circulation of a model gas in the evaluation test of the removal performance of ammonia performed in an Example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Further, in the following description and drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate description will be omitted. The ammonia-modified hydrogen supply device of the present invention includes a raw material supply device for supplying ammonia as a raw material and a reformed gas containing hydrogen by reforming the ammonia supplied from the raw material supply device. A hydrogen purification device provided with an ammonia reformer for producing the above-mentioned ammonia, an ammonia selective oxidation catalyst for oxidizing ammonia in the reforming gas supplied from the ammonia reformer, and oxygen being supplied to the hydrogen purification device. At least one selected from the group consisting of an acidic porous carrier and Cu and Ru supported on the acidic porous carrier, which is provided with an oxygen supply device for the above-mentioned ammonia selective oxidation catalyst. It is characterized in that it is a catalyst provided with the catalyst metal of. Further, in the ammonia-modified hydrogen supply method of the present invention, the ammonia as a raw material is supplied from the raw material supply device to the ammonia reformer by using the ammonia-modified hydrogen supply device of the present invention. After generating the quality gas, the reforming gas and the reforming gas are supplied by supplying oxygen from the oxygen supply device to the hydrogen purification device while supplying the reforming gas from the ammonia reformer to the hydrogen purification device. This method is characterized in that hydrogen is purified by bringing oxygen into contact with the ammonia selective oxidation catalyst and oxidizing the ammonia in the reforming gas, and the purified hydrogen is supplied.

FIG. 1 is a schematic view showing a preferred embodiment of the ammonia reformed hydrogen supply device of the present invention. The ammonia reforming type hydrogen supply device 1 shown in FIG. 1 includes a raw material supply device 10, an ammonia reformer 11, a hydrogen purification device 12, an oxygen supply device 13, and gas pipes 14a to 14e. In such a device 1, the raw material supply device 10 and the ammonia reformer 11 provide a gas pipe 14a so that the raw material supply device 10 can supply ammonia (raw material) to the ammonia reformer 11. Connected via. Further, the ammonia reformer 11 and the oxygen supply device 13 are connected via a gas pipe 14b so that oxygen can be supplied to the ammonia reformer 11 from the oxygen supply device 13. Further, in such an apparatus 1, the ammonia reformer 11 and the hydrogen purification apparatus 12 provide a gas pipe 14c so that the reforming gas can be supplied from the ammonia reformer 11 to the hydrogen purification apparatus 12. It is connected via. Further, the hydrogen purification device 12 and the oxygen supply device 13 are connected via a gas pipe 14d so that oxygen can be supplied to the hydrogen purification device 12 from the oxygen supply device 13. Further, a gas pipe 14e is connected to the hydrogen purification device 12 so that the purified hydrogen can be supplied to the outside through the gas pipe 14e. The arrows shown in the gas pipes 14a to 14e in FIG. 1 conceptually indicate the direction of the gas flowing in the gas pipe (the direction in which the gas flows).

The raw material supply device 10 may be any as long as it can supply ammonia as a raw material to the ammonia reformer 11, and its design and the like are not particularly limited, and known ones can be appropriately used. Such a raw material supply device 10 may include, for example, a tank (storage container) for storing ammonia. The tank provided in such a raw material supply device 10 is not particularly limited, but from the viewpoint of downsizing the device and being able to supply a larger amount of ammonia, ammonia can be used. A tank that can be stored in a liquid state can be preferably used. As a tank capable of storing such ammonia in a liquid state, for example, ammonia in a liquid state is stored at room temperature (about 20 ° C. to 25 ° C.) and several atm (about 8.6 atm to 10 atm). What is possible can be preferably used. When using a tank capable of storing such ammonia in a liquid state, it is possible to more easily replenish the tank with ammonia.

Further, when the raw material supply device 10 includes a tank capable of storing ammonia in a liquid state, the raw material supply device 10 can supply the ammonia in a gaseous state to the ammonia reformer 11. In addition, the raw material supply device 10 preferably further includes a vaporizer connected to the tank together with the tank. Such a vaporizer may be any one capable of vaporizing ammonia in a liquid state, and is not particularly limited, but can be vaporized by heating, for example, ammonia in a liquid state. A known vaporizer, such as one having a configuration, can be appropriately used. When such a tank and a vaporizer are used, the raw material supply device 10 stores the ammonia in the liquid state by, for example, a pump for introducing the ammonia in the liquid state from the tank into the vaporizer. A structure in which the tank to be used and the vaporizer are connected can be preferably used. Such a raw material supply device 10 makes it possible to supply gaseous ammonia to the ammonia reformer 11 via the gas pipe 14a.

The ammonia reformer 11 is provided on the downstream side of the raw material supply device 10, and is connected to the raw material supply device 10 via a gas pipe 14a. Further, the ammonia reformer 11 is also connected to the oxygen supply device 13 via a gas pipe 14b. Therefore, in the apparatus 1 of the present embodiment, it is possible to supply ammonia (gas) from the raw material supply device 10 to the ammonia reformer 11, and the oxygen supply device 13 to the ammonia reformer 11. It is also possible to supply oxygen (gas) from.

The configuration of such an ammonia reformer 11 is not particularly limited, and a known configuration can be appropriately used, and for example, one provided with a known ammonia reforming catalyst can be preferably used. In this way, when the ammonia supplied from the raw material feeder 10 is decomposed using the ammonia reforming catalyst, it is possible to efficiently generate a reformed gas containing _{hydrogen (H 2) by such a decomposition reaction.} is there. As such an ammonia reformer 11, a known container containing a known ammonia reforming catalyst or the like can be appropriately used.

When the ammonia reformer 11 includes the ammonia reformer, the ammonia reformer 11 includes an ammonia combustion catalyst for oxidizing ammonia by a chemical reaction between ammonia and oxygen to generate heat. A combustion part (oxidation part); a reforming part (decomposition part) provided with an ammonia reforming catalyst for decomposing ammonia by utilizing the heat generated in the combustion part to generate hydrogen and nitrogen; Can be preferably used. According to the ammonia reformer 11 provided with such a combustion unit and a reforming unit, in the combustion unit, a part of ammonia supplied from the raw material supply device 10 and oxygen supplied from the oxygen supply device 13 are separated. By bringing it into contact with the ammonia combustion catalyst, it becomes possible to oxidize ammonia to generate heat, and the heat generated by the oxidation reaction is burned with ammonia in the reforming section (ammonia supplied from the raw material supply device 10). Since it can be used for the decomposition reaction of the remaining part that was not burned by the part (the heat generated in the combustion part can be used for the decomposition reaction caused by bringing ammonia into contact with the ammonia reforming catalyst). (Because it is possible), it becomes possible to reform ammonia to generate hydrogen more efficiently. That is, a part of ammonia is oxidized in the combustion part, and the remaining ammonia is hydrogenated in the reforming part. As described above, according to the ammonia reformer 11 having the combustion unit and the reforming unit, it is possible to reform ammonia by the so-called autothermal reforming (ATR) method (as described above). The reformer 11 can be said to be a heat exchange type reformer). As the ammonia combustion catalyst used for such a combustion portion, a known catalyst that can be used for oxidizing ammonia can be appropriately used. For example, a catalyst metal composed of a carrier and a noble metal supported on the carrier ( Those having a metal active point) can be preferably used. Further, as the ammonia reforming catalyst used in the reforming section, a known ammonia reforming catalyst capable of reforming ammonia and decomposing it into hydrogen and nitrogen can be appropriately used, and the carrier and the carrier are not particularly limited. A catalyst metal (metal active point) made of a noble metal supported on the carrier can be preferably used. The carrier used for such an ammonia combustion catalyst and an ammonia reforming catalyst is not particularly limited, and a known carrier can be appropriately used, and for example, alumina, zeolite or the like may be appropriately used. Further, as the catalyst metal of the ammonia combustion catalyst, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, W, Re, Os, Ir and Pt can be used, among others. From the viewpoint of higher low temperature activity, V, Mn, Fe, Co, Ni, Pt, Cu and Ru are more preferable. Further, as the catalyst metal of the ammonia reforming catalyst, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, W, Re, Os, Ir and Pt can be used. Of these, Ru, Fe, Co, Ni, Mo, Rh, and Re are more preferable from the viewpoint of higher low-temperature activity. As the ammonia combustion catalyst and the ammonia reforming catalyst, those having the same configuration or those having different configurations may be used. Further, the method for preparing the ammonia combustion catalyst and the ammonia reforming catalyst is not particularly limited, and known methods can be appropriately used. Further, the forms of the ammonia combustion catalyst and the ammonia reforming catalyst are not particularly limited, and the forms can be appropriately changed and used according to a desired design. For example, they can be used as pellets or groups having various shapes. A catalyst may be supported on a material (for example, a honeycomb monolith-like base material).

Further, such an ammonia reformer 11 may have, for example, a form having the combustion portion on the upstream side and the reformer on the downstream side, or a partition plate in the reformer 11. The combustion part and the reforming part are partitioned by appropriately using the above, and the partition is formed as a structure in which oxygen and ammonia flow through the combustion part and only ammonia flows through the reforming part. It may be used in various forms such as a form in which the heat of the combustion part is conducted to the reformed part through the plate. The configuration (form) of such an ammonia reformer 11 is not particularly limited, and a known configuration (for example, the configuration of the reformer disclosed in Japanese Patent Application Laid-Open No. 2019-53855 (method of connecting gas pipes, etc.) ) Etc.) may be used as appropriate. Further, the configuration of the reformer 11 is not limited to the above, and for example, a heater or the like for generating heat for decomposing ammonia may be separately provided. Further, the hydrogen purification apparatus 12 may be used as a separately provided with a known heat exchanger or the like so that the reformed gas flowing in the gas pipe has an appropriate temperature. As described above, the hydrogen purification apparatus 12 may be appropriately provided with heating means (heater or the like), cooling means, or the like, depending on the intended design.

The hydrogen refiner 12 is provided on the downstream side of the ammonia reformer 11, and is connected to the ammonia reformer 11 via a gas pipe 14c. Further, the hydrogen purification device 12 is also connected to the oxygen supply device 13 via a gas pipe 14d. Therefore, in the apparatus 1 of the present embodiment, the reforming gas generated by the ammonia reformer 11 can be supplied from the ammonia reformer 11 to the hydrogen purification apparatus 12, and the oxygen feeder 13 can be supplied. It is also possible to supply oxygen to the hydrogen purification apparatus 12 from.

Such a hydrogen purification device 12 includes the ammonia selective oxidation catalyst. Such a hydrogen purification apparatus 12 may be provided as long as it includes the ammonia selective oxidation catalyst, and its configuration is not particularly limited. Therefore, the hydrogen purification device 12 has the same form as the catalyst reaction device (fixed bed flow type reaction device, fluid bed type reaction device, etc.) having a known configuration except that the catalyst type is the ammonia selective oxidation catalyst. May be used as appropriate. Further, such a hydrogen purification apparatus 12 may be provided with a container for accommodating the ammonia selective oxidation catalyst, depending on its design. The container is not particularly limited as such, and a known container can be used as appropriate.

Further, the ammonia selective oxidation catalyst provided in such a hydrogen purification apparatus 12 is an acidic porous carrier and at least one catalyst metal (at least one catalyst metal selected from the group consisting of Cu and Ru supported on the acidic porous carrier). It is a catalyst having a metal active point of the catalyst). Examples of such an acidic porous carrier include zeolite (the type of zeolite is not particularly limited, and A type, ferrierite type, MCM-22 type, ZSM-5 type, mordenite (MOR) type, L type, and Y type. Any type such as type, X type, β type (beta type), etc.), phosphoric acid compound, SiO _2- Al ₂ O ₃ , WO _3- ZrO ₂ , and MOF can be preferably used. Further, among such acidic porous carriers, zeolite is more preferable, β-type zeolite and ZSM-5 type zeolite are more preferable, and β-type zeolite is more preferable from the viewpoint that acidity and pore diameter can be easily controlled. Is particularly preferable. Such an acidic porous carrier may be appropriately produced and used by a known method, or if there is a commercially available product, a commercially available product may be used.

Further, the catalyst metal (metal active site) in the ammonia selective oxidation catalyst is composed of at least one selected from the group consisting of copper (Cu) and ruthenium (Ru). As described above, according to the catalyst in which the catalyst metal (metal active point) is Cu and / or Ru, the metal active point makes it difficult to activate hydrogen, so that the reaction for oxidizing ammonia is sufficiently selectively induced. It can be raised, and even when hydrogen and ammonia coexist, ammonia can be sufficiently oxidized and removed. When the catalyst metal (metal active site) is made of a metal other than Cu and / or Ru, ammonia cannot be sufficiently selectively oxidized. For example, when a noble metal (Pt, Pd, etc.) other than Cu and Ru is used as a catalyst metal (metal active point of the catalyst), when a gas in which hydrogen, ammonia, and oxygen coexist is brought into contact, hydrogen and oxygen are generated. (Reaction described in the above reaction formula 2) is preferentially triggered, oxygen is consumed for the oxidation of hydrogen, and hydrogen is sufficiently purified (ammonia is removed from the reforming gas). Becomes difficult.

As the catalytic metal (Cu and / or Ru) forming such a catalytic active site, Cu is more preferable from the viewpoint of raw material price and resource amount, and Ru is more preferable from the viewpoint of reaction activity.

The amount of Cu and Ru supported on the catalyst metal in the ammonia selective oxidation catalyst (total amount of Cu and Ru) is not particularly limited, but is 0 with respect to the total amount of the ammonia selective oxidation catalyst. It is preferably 0.05 to 10% by mass (more preferably 0.1 to 7% by mass). When the catalyst metal is made of Cu, the amount of Cu supported on the total amount of the ammonia selective oxidation catalyst is more preferably 2 to 8% by mass, and particularly preferably 3 to 7% by mass. Further, when the catalyst metal is composed of Ru, the supported amount of Ru with respect to the total amount of the ammonia selective oxidation catalyst is more preferably 0.05 to 1% by mass, and more preferably 0.1 to 0.5% by mass. Especially preferable. If the amount of the catalyst metal supported is less than the lower limit, the NH ₃ removal performance tends to deteriorate, while if it exceeds the upper limit, a portion not involved in the reaction tends to occur and is wasted.

The method for producing such an ammonia selective oxidation catalyst is not particularly limited, and a known method can be appropriately used. For example, a known method capable of supporting a metal on a carrier is appropriately adopted to prepare an acidic porous carrier. A method for producing an ammonia selective oxidation catalyst may be adopted by supporting at least one metal selected from the group consisting of Cu and Ru. Further, as a method for producing such an ammonia selective oxidation catalyst, for example, at least one metal salt (nitrate, chloride, acetate, etc.) selected from the group consisting of Cu and Ru, or a complex of the metal can be used. A method of immersing the acidic porous carrier in a solution dissolved in a solvent such as water or alcohol to remove the solvent and then firing the mixture can be preferably used. The form of the ammonia selective oxidation catalyst is not particularly limited, and the form can be appropriately changed and used according to the desired design. For example, the form may be pelletized or a substrate having various shapes (for example, honeycomb monolith). A catalyst may be supported on a base material or the like). The hydrogen purification apparatus 12 may be appropriately provided with a known heat exchanger or the like so that the gas flowing in the gas pipe has an appropriate temperature. Further, in the hydrogen purification apparatus 12, in order to maintain a state of high catalytic activity and allow the reaction to proceed more efficiently, the temperature of the ammonia selective oxidation catalyst itself in the apparatus and the gas to be brought into contact with the ammonia selective oxidation catalyst are charged. Heating means, cooling means, and the like may be appropriately provided so that the temperature and the like can be appropriately controlled.

The oxygen supply device 13 is connected to the ammonia reformer 11 and the hydrogen purification device 12 via gas pipes 14b and 14d, respectively. As such an oxygen supply device 13, a device capable of supplying a required amount of oxygen to the ammonia reformer 11 and the hydrogen purification device 12, respectively, can be used as appropriate. The oxygen supply device 13 may be capable of supplying a required amount of oxygen to the ammonia reformer 11 and the hydrogen purification device 12 by supplying a gas containing oxygen (for example, air), and further. , The required amount of oxygen may be able to be supplied to the ammonia reformer 11 and the hydrogen purification device 12 alone. As described above, the oxygen supply device 13 may be any as long as it can supply oxygen as a result, and is not particularly limited, and a known device can be appropriately used, for example, a compressor, an air pump, a cylinder, and an intake air. Those equipped with a means (fan, etc.) capable of supplying gas (blowing, etc.) to a gas pipe (gas pipe for supplying oxygen gas) having a structure capable of taking in air from the mouth (fan, etc.) It may be a housing) or the like.

Further, the gas pipes 14a to 14e are not particularly limited as long as they can allow gas to flow through the pipes, and known gas pipes 14a to 14e can be appropriately used according to the size and design of the apparatus. .. In addition, in order to efficiently circulate the gas in the gas pipes 14a to 14e, the gas pipes 14a to 14e and other components (such as the above-mentioned ammonia reformer 11 and the hydrogen purification device 12) have a fan, an injector, and a valve. A means capable of adjusting the flow rate of gas or the like such as, etc. may be appropriately provided. Further, the gas pipes 14a to 14e and other components (such as the above-mentioned ammonia reformer 11 and the hydrogen purification device 12) are known as heat exchangers and known so that the temperature of the gas becomes a desired temperature. The heating means, cooling means, and the like may be appropriately provided, and the design can be appropriately changed according to the type and application of the catalyst to be used. Further, in order to control the amount of oxygen used for the reaction, the temperature of the gas, etc., in each gas pipe or in the vicinity of the reformed gas discharge port of the ammonia reformer 11 (gas pipe 14C and the ammonia reformer 11). A component in the gas (for example, ammonia) is located at an appropriate site such as (near the connection with the gas) or near the inlet of the reforming gas of the hydrogen purification device 12 (near the connection between the gas pipe 14C and the hydrogen purification device 12). Various known sensors such as a sensor for measuring the concentration of the gas and a sensor for measuring the temperature of the gas may be appropriately installed, and the oxygen supply device 13 and the heating may be installed according to the information from these sensors. The operating conditions of the means and the like may be controlled to appropriately control the amount of oxygen supplied, the temperature of the gas, and the like. When the device 1 is mounted on an automobile, for example, it is based on data obtained from various sensors by using a computer of a so-called engine control unit (ECU) for controlling the driving state of the engine of the automobile. Therefore, the gas supply amount (flow rate), the gas temperature, etc. are appropriately controlled by appropriately controlling the operating conditions and the like of the various constituent parts (oxygen supply device 13, the heating means provided in some cases, etc.) included in the apparatus 1. You may.

Hereinafter, a method of supplying hydrogen using the ammonia-modified hydrogen supply device of the embodiment shown in FIG. 1 (a preferred embodiment of the ammonia-modified hydrogen supply method of the present invention) will be described.

In such an ammonia reforming hydrogen supply method, first, ammonia as a raw material is supplied from the raw material supply device 10 to the ammonia reformer 11. Such a method of supplying ammonia from the raw material supply device 10 to the ammonia reformer 11 differs depending on the configuration of the raw material supply device 10, and is not particularly limited. For example, as the raw material supply device 10. In the case of using the above-mentioned tank (storage container) for storing ammonia and a vaporizer, the liquid ammonia introduced into the vaporizer from the tank is vaporized (gasified) by the vaporizer. By introducing the generated gaseous ammonia into the gas pipe 14a, it is possible to adopt a method of supplying gaseous ammonia from the raw material supply device 10 to the ammonia reformer 11.

Further, in such a method, after supplying ammonia (raw material) to the ammonia reformer 11 as described above, the ammonia reforming reaction is allowed to proceed in the reformer 11. By such a reaction, it becomes possible to generate a reforming gas in the ammonia reformer 11. In such an ammonia reformer 11, similarly to the known reformer, a reforming gas may be generated by utilizing a known reforming reaction of ammonia, depending on the structure of the reformer. Then, the reformed gas may be generated by appropriately adopting appropriate conditions so that the reaction proceeds sequentially. As described above, the method itself for producing the reformed gas is not particularly limited, and a known method can be appropriately used. The composition of such a reforming gas differs depending on the reaction form of the reforming reaction of ammonia generated in the reformer 11, but hydrogen, nitrogen, water, and ammonia (ammonia remaining without reaction). And can be included. For example, with respect to the generation of such reformed gas, an ammonia reformer having the combustion portion on the upstream side and having a configuration in which the gas after combustion comes into contact with the reforming portion on the downstream side in the combustion portion. Considering the case where 11 is used, first, when ammonia is introduced into the ammonia reformer 11 via the gas pipe 14a and oxygen is introduced through the gas pipe 14b, oxygen is introduced in the combustion portion on the upstream side. And ammonia come into contact with the ammonia combustion catalyst, the reaction (reaction of oxygen and ammonia) described in the above reaction formula 1 occurs, and nitrogen (N ₂ ) and water (H ₂ O) are generated on the upstream side. Since heat is generated and the generated heat can be used to activate the ammonia reforming catalyst in the reforming part on the downstream side, the decomposition reaction of Ammonnia (reaction in which nitrogen and hydrogen are generated) on the downstream side. ) Can be efficiently generated and a reforming gas can be generated. When such a reaction is used, the reformed gas obtained may contain nitrogen and water generated on the upstream side and nitrogen and hydrogen generated on the downstream side, and further react. It may contain residual raw material gas (ammonia). When the ammonia reformer 11 having such a combustion part and a reforming part is used, the ratio of ammonia and oxygen supplied to the reformer 11 is not particularly limited, and the combustion part and the reforming part It may be set appropriately according to the type and performance. The method of supplying oxygen is not particularly limited, and oxygen may be supplied as a result by supplying air from the oxygen supply device 13. Further, in the case where the ammonia reformer 11 is provided with the reformer and the heater for supplying heat to the reformer, the heat from the heater can be used. It is not always necessary to utilize the reaction in the combustion section (combustion reaction of ammonia), and in this case, oxygen does not have to be particularly supplied to the reformer 11. When the combustion reaction of ammonia is not utilized by utilizing the heat of the heater in this way, the reformed gas produced may contain hydrogen, nitrogen and ammonia. In this way, the necessity of supplying oxygen to the ammonia reformer 11 can be appropriately changed according to the configuration of the apparatus, and the composition of the reformed gas produced as a result can be different.

In the step of generating the reformed gas from ammonia as described above, the ammonia reformer 11 is reformed from ammonia by using a known means (known reformer) capable of reforming ammonia. A known method for generating gas can be appropriately applied, and known conditions can be appropriately adopted for the amount of ammonia and oxygen used, the temperature of the catalyst to be used, and the like. The theoretical amount that can be decomposed in the reformer 11 used (the amount that can be theoretically decomposed in relation to the amount of catalyst, etc .: calculated in advance by mapping the relationship between the amount of catalyst and the amount of gas, etc.) When ammonia is used, in the reformer 11, the composition of the reformed gas produced is composed of excess hydrogen and a small amount of ammonia (ammonia that remains without reaction) in terms of volume ratio. It is also possible to make it a state in which is included.

Further, in such an ammonia reforming type hydrogen supply method, as described above, after the reforming gas is generated, the reforming gas is transferred from the ammonia reformer 11 to the hydrogen purification device 12 via the gas pipe 14c. While supplying, oxygen is supplied from the oxygen supply device 13 to the hydrogen purification apparatus 12 via the gas pipe 14d, so that the reforming gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst in the reforming gas. Oxidizes the ammonia in the gas.

As described above, in the present invention, after the reformed gas is generated, ammonia is oxidized by the ammonia selective oxidation catalyst provided in the hydrogen purification apparatus 12. The method of supplying oxygen used for such oxidation from the oxygen supply device 13 is not particularly limited, and oxygen may be supplied as a result by supplying air from the oxygen supply device 13. Ammonia is produced by the ammonia selective oxidation catalyst according to the present invention, which comprises the acidic porous carrier and at least one catalyst metal selected from the group consisting of Cu and Ru supported on the acidic porous carrier. The reason why it is possible to sufficiently oxidize (selectively oxidize) is not always clear, but the present inventors infer as follows. That is, first, when oxygen and the reforming gas are brought into contact with the ammonia selective oxidation catalyst, the acidic porous carrier in the ammonia selective oxidation catalyst causes adsorption of ammonia and concentration of ammonia on the carrier, and then the catalyst. The metal makes it possible to react the adsorbed ammonia with oxygen. Since hydrogen in the reformed gas is not easily adsorbed on the carrier and the HH bond is not easily dissociated on the metal even when it comes into contact with the ammonia selective oxidation catalyst, a reaction in which water is generated by hydrogen and oxygen (above). It is presumed that the reaction between ammonia and oxygen can be triggered preferentially over the reaction described in Reaction Scheme 2). Therefore, according to the ammonia selective oxidation catalyst, ammonia can be sufficiently selectively oxidized, and ammonia is sufficiently oxidized and removed from the reformed gas to generate fully purified hydrogen (gas). The present inventors speculate that this is possible.

Further, when the reformed gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst, the contact gas (of the reformed gas and the oxygen) is used so that the reaction proceeds more efficiently depending on the type of catalyst and the like. It is preferable to control the temperature of the mixed gas). When the reformed gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst, the temperature of the contact gas is more preferably 350 ° C. to 750 ° C. (more preferably 400 ° C. to 700 ° C.). If the temperature of the contact gas with the ammonia selective oxidation catalyst is less than the lower limit, it is difficult to increase the activity of the metal, and the ability to remove ammonia tends to be low, while exceeding the upper limit. And the adsorption of ammonia to the carrier is hindered, and on the contrary, the ammonia removal performance tends to deteriorate.

Further, when the reforming gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst, the supply ratio of oxygen and ammonia (ammonia in the reforming gas) at the time of contacting with the ammonia selective oxidation catalyst is the volume ratio ( [Oxygen (O ₂ )] / [Ammonia (NH ₃ )]) is preferably 0.75 to 20 (more preferably 0.75 to 10). If the volume ratio is less than the lower limit, oxygen becomes insufficient and ammonia tends to remain without being oxidized. On the other hand, if the volume ratio exceeds the upper limit, excess oxygen reacts with hydrogen and is purified by a reformer. It tends to waste hydrogen. The method of bringing the contact gas (mixed gas) having such a volume ratio into contact with the ammonia selective oxidation catalyst is not particularly limited, and for example, a sensor capable of measuring the concentration of ammonia gas in the apparatus 1 is appropriately used. Then, the concentration of ammonia in the reforming gas supplied to the hydrogen purification device 12 is confirmed by the sensor, and the oxygen supply device 13 is supplied with the required amount of oxygen so that the required amount of oxygen is supplied from the oxygen supply device 13. A method of controlling operation or the like can be appropriately adopted.

When the reformed gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst, the flow rate of the contact gas (mixed gas of the reformed gas and the oxygen) is not particularly limited, and depending on the type of catalyst, the flow rate is not particularly limited. It may be set appropriately.

In this way, the reforming gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst to oxidize the ammonia in the reforming gas to purify hydrogen, which is obtained after purification in this manner. As the gas containing hydrogen (hereinafter, for convenience, simply referred to as "purified gas" in some cases), it is preferable that the gas has an ammonia content of 0.1 ppm or less. If the concentration of ammonia in such a refined gas exceeds the above upper limit, for example, when the refined gas (hydrogen) is supplied to the PEM type (solid polymer type) fuel cell, the PEM type fuel cell is deteriorated. There is a tendency. In addition, the type of the ammonia selective oxidation catalyst, the amount used thereof, and the ammonia selection are taken into consideration in consideration of the application, the overall size of the apparatus 1 itself, and the like so that the content of ammonia in the purified gas is 0.1 ppm or less. It is preferable to appropriately design and use the apparatus 1 in consideration of the relationship between the amount of gas supplied to the oxidation catalyst, the temperature, and the like in advance.

In this way, after the hydrogen is purified by bringing the reformed gas and the oxygen into contact with the ammonia selective oxidation catalyst, the purified hydrogen is supplied to the outside through the gas pipe 14e (ammonia is used). (Supplying a purified gas containing sufficiently removed hydrogen) becomes possible. The supply destination of hydrogen after such purification is not particularly limited, but a PEM type fuel cell can be mentioned as a suitable one.

Although the preferred embodiments of the ammonia reforming hydrogen supply device and the ammonia reforming hydrogen supply method of the present invention have been described above with reference to FIG. 1, the ammonia reforming hydrogen supply device and the ammonia reforming of the present invention have been described with reference to FIG. The type hydrogen supply method is not limited to the above embodiment. For example, in the ammonia reforming hydrogen supply device 1 of the embodiment shown in FIG. 1, the oxygen supply device 13 is connected to the ammonia reformer 11, but in the ammonia reforming hydrogen supply device of the present invention, hydrogen is used. The relationship between the oxygen supply device and the hydrogen purification device 12 is not particularly limited as long as the relationship between the oxygen supply device and the hydrogen purification device 12 is configured so that oxygen can be supplied to the purification device 12. Further, in the ammonia reforming hydrogen supply device 1 of the embodiment shown in FIG. 1, one oxygen supply device 13 is used, but in the present invention, the number of oxygen supply devices 13 is not particularly limited. For example, two oxygen supply devices 13 may be used to connect separate oxygen supply devices 13 to the ammonia reformer 11 and the hydrogen purification device 12. Further, in the ammonia-modified hydrogen supply device 1 of the embodiment shown in FIG. 1, the raw material supply device 10 and the ammonia reformer 11 are connected by a single linear gas pipe 14a, but the raw material is supplied. The apparatus 10 and the ammonia reformer 11 may be configured so that ammonia is supplied from the raw material supply device 10 to the ammonia reformer 11, and the shape and number of gas pipes used for the supply are particularly important. Without limitation, for example, these may be connected by a plurality of gas pipes, or may be connected by a gas pipe branched from the middle. When the ammonia reformer 11 includes the combustion unit and the reformer, for example, by connecting the raw material supply device 10 and the ammonia reformer 11 with a gas pipe branched from the middle, each unit can be connected. The amount of ammonia supplied may be adjusted. As described above, the ammonia-reformed hydrogen supply device and the ammonia-reform-type hydrogen supply method of the present invention are not limited to the above-described embodiment, and the design and the like are designed according to the application, the target size, and the like. It may be changed as appropriate.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Example 1)
<Catalyst A preparation process>
First, β-type zeolite (β-zeolite: trade name “HSZ-931HOA” manufactured by Tosoh Corporation) is prepared, and 20 g of the β-zeolite is added to copper acetate (Cu (CH ₃ COO) ₂・ H _2). It was immersed in 200 mL of an aqueous solution containing 0.63 g of O). Then, after evaporating water from the aqueous solution, the obtained solid content was heated in the air at 300 ° C. for 3 hours, and then a mixed gas of hydrogen and nitrogen (volume ratio: H ₂ / N ₂ = 5 /). 95) The catalyst A was calcined by heating at 500 ° C. for 5 hours in an atmosphere to obtain a catalyst A provided with a carrier made of β-zeolite and Cu (supported amount: 1.0% by mass) supported on the carrier. .. Next, the obtained catalyst A was powder-molded, crushed, and granulated to form pellet-shaped catalyst A [carrier: β-zeolite, catalyst metal: Cu (supported amount: Cu)) having a diameter of 0.5 to 1.0 mm. 1.0% by mass)] was obtained.

<Ammonia removal performance evaluation test>
First, a fixed-bed circulation type reactor (trade name "CATA-5000-6" manufactured by Best Instruments Co., Ltd.) was used, and the quartz reaction tube (cylindrical reaction tube) of the device was used as described above. The pellet-shaped catalyst A (2.0 g) obtained in the above was filled and fixed (installed) in the central portion of the reaction tube using quartz glass wool (hereinafter, simply referred to as “glass wool”). That is, as schematically shown in FIG. 2, a layer (catalyst 101) made of the catalyst A (2.0 g) is provided in the central portion of the reaction tube 100 by sandwiching it between two glass wools 102 to form a cylindrical shape. The catalyst A (catalyst 101) was fixed (installed) in the reaction tube 100. The arrow shown in FIG. 2 conceptually indicates the direction in which the gas introduced into the reaction tube 100 flows (the direction of the air flow). The cylindrical reaction tube 100 is a reaction tube made of quartz having a diameter (inner diameter) of 16 mm, and the catalyst 101 is a pellet-shaped catalyst A (2.0 g) having a thickness of 20 mm (catalyst volume: 4.0 mL). ) Was installed and formed so as to be a catalyst layer, and both the glass wool 102 on the upstream side and the glass wool 102 on the downstream side were used so as to have a thickness of 4 mm (volume: 1.0 mL). Next, the cylindrical reaction tube 100 after installing 2.0 g of the catalyst A (catalyst 101) in the central portion in this way is placed in the fixed bed flow type reaction device so that it can be heated in the heating furnace in the device. installed. Then, using the apparatus, in the cylindrical reaction tube 100 provided with the catalyst A (catalyst 101), the model gas having the composition shown in Table 1 below (the reformed gas reformed by the ammonia reformer) is used. gas imitating the oxygen mixed gas obtained by adding for: since in a fixed bed flow type reactor for use is difficult measurement of gas containing a high concentration of hydrogen, and diluted with N ₂ is an inert gas (A gas having a composition as shown in Table 1 is used as a model gas) was flowed at a flow rate of 10 L / min.

Then, after starting the circulation of such a model gas (hereinafter, referred to as “injection gas” in some cases), the fixed bed flow type reaction with respect to the catalyst A (catalyst 101) in the reaction tube 100 (catalyst bed). Pretreatment was performed by flowing a heated model gas using the heating furnace of the device. Here, in the heating pretreatment (hereinafter, for convenience, simply referred to as "first heat treatment" in some cases), the temperature of the model gas (input gas) to be circulated with respect to the catalyst A (catalyst 101) is measured at the lower limit of measurement. The temperature is _{raised from the temperature (T low} ) to the upper limit temperature for measurement ( _High ) under the condition of 40 ° C./min _{, and after holding at the upper limit temperature for measurement (High} ) for 5 minutes, the temperature lowering rate: -20 ° C. The temperature was lowered under the condition of / minute, and the temperature was _{maintained at the lower limit temperature (Tlow} ) for 10 minutes to heat the catalyst A (catalyst 101).

Then, after such a heat pretreatment (first heat treatment), the model gas continues to flow under the same conditions (10 L / min) to the catalyst A (catalyst 101) in the reaction tube 100 (catalyst bed). On the other hand, a heat treatment (hereinafter, heating) in which the temperature of the model gas (input gas) is raised (heated) under the condition of a heating rate of 10 ° C./min from the lower limit temperature of measurement ( _Tlow ) to the upper limit temperature of measurement ( _High). For convenience, it was simply referred to as "second heat treatment"). Both the first heat treatment and the second heat treatment were performed under the model gas air flow (flow rate: 10 L / min) as described above, and these treatments were continuously performed. Here, FIG. 3 shows a heating sequence (heat treatment procedure: a graph showing the relationship between the heating temperature and time) for the catalyst A after the flow of the model gas is started. The temperatures shown in FIG. 3 ( _Tlow , _High, etc.) are all the temperatures of the model gas.

Then, using the fixed bed flow type reactor, while performing the heat pretreatment (first heat treatment) and the second heat treatment, after contacting the catalyst A (catalyst 101), the reaction tube is subjected to. _{The concentration of components (NH 3} , H ₂ , O ₂ , nitrogen oxides) contained in the gas discharged from the outlet (hereinafter, in some cases, simply referred to as “exhaust gas”) was analyzed (measured). _{Then, from such analysis results, in particular, using the data of the concentration of NH 3} contained in the exhaust gas during the second heat treatment, in the incoming gas (model gas) before contacting with the catalyst. the amount of NH ₃ in, in contrast to the amount of NH ₃ in the exit gas was determined NH ₃ removal of the catalyst a of (NH ₃ purification rate). At the time of such measurement, the lower limit temperature ( _Tlow ) of measurement was set to 150 ° C., and the upper limit temperature ( _High ) of measurement was set to 650 ° C. The NH ₃ removal rate (unit:%) is calculated by the following formula (A) :.
[NH ₃ removal rate _{(%)] = {(X} NH3 -Y NH3) / X NH3} × 100 (A)
[In the above formula _{(A), X NH3} represents the amount of NH ₃ in the inflow gas (model gas) (volume _{fraction), Y NH3} indicates the amount of NH ₃ in the exit gas (volume fraction). _{Therefore, the value of (X NH3-} Y _NH3 ) in the formula (A) is the amount (volume fraction) of _{NH 3} removed by the contact of the catalyst. ]
Calculated by Then, NH ₃ and the maximum value of the removal rate, NH ₃ heating temperature when the removal rate is maximum (the inlet gas temperature: _{T m)} and the heating temperature (entrance at which NH ₃ removal rate was 10% The temperature of the gas: T ₁₀ ) was determined. The results obtained are shown in Table 2. Table 2 also shows the lower limit temperature for measurement ( _Tlow ) and the upper limit temperature for measurement ( _{High) during the heat treatment.}

(Examples 2 to 5 and Comparative Examples 1 to 2)
One of the catalysts B to G prepared as described below instead of using the catalyst A by changing the type of catalyst for each Example and each Comparative Example (Example 2: Catalyst B, Example 3: Catalyst C, Example 4: catalyst D, Example 5: catalyst E, Comparative Example 1: catalyst F, Comparative Example 2: catalyst G) are used and measured under the condition of a usage amount of 2.0 g. Each of them is the same as the "evaluation test of ammonia removal performance" adopted in Example 1 except that the lower limit temperature ( _Tlow ) and the upper limit measurement temperature ( _{High) are changed to the temperatures shown in Table 2.} the catalyst has a maximum value of the NH ₃ removal rate, NH ₃ heating temperature when the removal rate is maximized and _{(T m),} NH ₃ heating temperature when the removal rate was 10% (of the inflow gas temperature: T ₁₀ ) was calculated. The results obtained are shown in Table 2. Regarding the catalysts used in Comparative Examples 1 and 2, _{the purification rate of NH 3} was always 0 (%) in the temperature range between the _{lower limit temperature for measurement (Tlow} ) and the upper limit temperature for measurement ( _High). The catalysts B to E used in Examples 2 to 5 (both used as pellets) and the catalysts F to G used for comparison in Comparative Examples 1 and 2 (both used as pellets) are as follows. Manufactured as follows.

<Catalyst B preparation process>
The same step as the preparation step of the catalyst A adopted in Example 1 except that the amount of copper acetate (Cu (CH ₃ COO) ₂ · H _{2 O) in the aqueous solution is changed from 0.63 g to 2.1 g.} By adopting the step, a catalyst B (pellet-shaped: a catalyst having a supported amount of Cu of 3.3% by mass) having a carrier made of β-zeolite and Cu supported on the carrier was obtained.

<Catalyst C preparation process>
ZSM is the same as the catalyst B preparation step described above, except that 20 g of ZSM-5 type zeolite (trade name "HSZ-822HOA" manufactured by Toso Co., Ltd.) is used instead of β-zeolite. A catalyst C (pellet-shaped: a catalyst having a supported amount of Cu of 3.3% by mass) having a carrier made of −5 type zeolite and Cu supported on the carrier was obtained.

<Catalyst D preparation process>
The same process as the above-mentioned catalyst B preparation process was adopted except that 20 g of mordenite (MOR) type zeolite (trade name “HSZ-660HOA” manufactured by Toso Co., Ltd.) was used instead of β-zeolite. , A catalyst D having a carrier made of MOR and Cu supported on the carrier (pellet-like: catalyst having a supported amount of Cu of 3.3% by mass) was obtained.

<Catalyst E preparation process>
Example 1 except that 0.81 g of an aqueous solution containing 3.9% by mass of ruthenium was used instead of using an aqueous solution containing 0.63 g of a copper acetate (Cu (CH ₃ COO) ₂ · H _{2 O).} By adopting the same step as the preparation step of the catalyst A adopted in the above, the catalyst E having a carrier made of β-zeolite and Ru supported on the carrier (pellet-like: supported amount of Ru is 0.15 mass by mass). % Catalyst) was obtained.

<Catalyst F preparation process>
Example 1 except that 1.1 g of an aqueous solution containing 2.0% by mass of palladium was used instead of using an aqueous solution containing 0.63 g of copper acetate (Cu (CH ₃ COO) ₂ · H _{2 O).} In the same manner as above, a comparative catalyst F (pellet-shaped: catalyst having a supported amount of Pd of 0.22% by mass) having a carrier made of β-zeolite and Pd supported on the carrier was obtained.

<Catalyst G preparation process>
Example 1 except that 1.1 g of an aqueous solution containing 2.0% by mass of platinum was used instead of using an aqueous solution containing 0.63 g of a copper acetate (Cu (CH ₃ COO) ₂ · H _{2 O).} In the same manner as above, a comparative catalyst G (pellet-shaped: catalyst having a supported amount of Pt of 0.22% by mass) having a carrier made of β-zeolite and Pt supported on the carrier was obtained.

As is clear from the results shown in Table 2, when a catalyst in which the catalyst metal is Cu or Ru is used (Examples 1 to 5), the proportion of ammonia in the model gas is 27.2% or more. It was confirmed that it was removed in. From these results, by using a catalyst in which the catalyst metal is Cu or Ru (Examples 1 to 5), ammonia can be sufficiently removed from the reformed gas containing excess hydrogen with respect to ammonia. It was found that it is possible to supply purified gas (hydrogen).

On the other hand, when a comparative catalyst in which the catalyst metal is Pd or Pt is used (Comparative Examples 1 and 2), as described above, between the _{lower limit temperature for measurement (Tlow} ) and the upper limit temperature for measurement ( _{High). The purification rate of NH 3} was always 0 (%) in the temperature range of, _{and the corresponding data of T m} and T ₁₀ could not be measured. From these results, when a comparative catalyst in which the catalyst metal is Pd or Pt is used (Comparative Examples 1 and 2), ammonia is added when a mixed gas containing hydrogen, ammonia and oxygen is brought into contact with each other. It was found that it could not be oxidized and removed.

The present inventors consider such a result as follows. That is, first, as the reactions that can occur when a mixed gas containing hydrogen, ammonia, and oxygen are brought into contact with the catalyst, the reactions described in the above reaction formula 1 (4NH ₃ + 3O ₂ → 2N ₂ + 6H ₂ O) and , The reaction described in the above reaction formula 2 (2H ₂ + O ₂ → 2H ₂ O) can be considered. Here, since hydrogen has a lower ignition temperature and a smaller minimum ignition energy than ammonia, in general, among the above reactions, the reaction described in the reaction formula 2 is more easily triggered than the reaction formula 1. It is clear that there is a tendency to Therefore, when a mixed gas containing hydrogen, ammonia, and oxygen is brought into contact with the catalyst to attempt to oxidize the components in the mixed gas, the reaction described in Reaction Scheme 2 generally occurs preferentially, and the reaction occurs. It is considered that more oxygen will be consumed in the reaction described in Equation 2. In particular, when a mixed gas containing excess hydrogen is brought into contact with ammonia, the contact probability with respect to the catalyst metal is much higher with hydrogen than with ammonia, so basically almost all of them. It is considered that oxygen is consumed in the reaction described in _{Reaction Scheme 2 (2H 2} + O ₂ → 2H _{2 O).} Therefore, in Comparative Examples 1 and 2, _{all the oxygen in the model gas from the lower limit of measurement temperature (T low} ) is used for the oxidation of hydrogen (the reaction described in the reaction formula 2), and the lower limit temperature of measurement (T _low ). It is considered that the purification rate _{of NH 3} was always 0 (%) in the temperature range between the upper limit temperature of measurement ( _High). On the other hand, when a catalyst in which the catalyst metal is Cu or Ru is used (Examples 1 to 5), the results (results shown in Table 2) indicate that excess hydrogen is contained with respect to ammonia. It can be seen that the reaction described in Reaction Scheme 1 for removing ammonia occurs even when the mixed gas is brought into contact with the gas. Considering that the model gas is a mixed gas containing excess hydrogen with respect to ammonia as shown in Table 1, the results shown in Table 2 show that the catalyst metal is Cu or Ru (Example). It is clear that 1 to 5) can sufficiently oxidize and remove ammonia having a low contact probability in the first place, and it is considered that ammonia can be sufficiently selectively oxidized. As described above, since the catalyst in which the catalyst metal is Cu or Ru can sufficiently selectively oxidize ammonia, in Examples 1 to 5, ammonia is sufficiently oxidized and removed. The present inventors presume that this has become possible.

Further, considering that only the amount of the catalyst metal (Cu) supported is different between the catalyst used in Example 1 and the catalyst used in Example 2, when the catalyst metal is Cu from these comparisons. When the supported amount of Cu is 3.3% by mass (Example 2), the removal performance of ammonia is higher than that when the supported amount of Cu is 1.0% by mass (Example 1). It turned out to be a good thing. _{From the measurement data from the lower limit temperature (Tlow} ) to the upper limit temperature ( _High ) during the second heat treatment, the temperature at which the ammonia removal rate is 10% or more (sufficiently high). _{The lower limit (value of T 10} ) of the temperature at which the ammonia purification activity is exhibited is 408 ° C. when the amount of Cu carried is 3.3% by mass (Example 2), and the amount of Cu carried is 1. It was also found that the temperature was 510 ° C. in the case of 0% by mass (Example 1). From these results, when the amount of Cu supported is 3.3% by mass (Example 2), compared with the case where the amount of Cu supported is 1.0% by mass (Example 1), It was also found that it can exhibit the ability to sufficiently oxidize and purify ammonia from lower temperatures (catalytic activity).

In addition, considering that the catalysts used in Examples 2 to 4 differ only in the type of carrier, when these are compared, when β-zeolite is used as the carrier (Example 2), other types of catalysts are used. It was confirmed that the removal rate of ammonia was higher than that when zeolite was used (Examples 3 and 4), and it was found that β-zeolite can be used more preferably as a carrier. (As is clear from Table 2, in Example 3 and Example 4, the maximum values of the ammonia removal rate are 81.2% and 60.4%, respectively, whereas in Example 2 The maximum value of the ammonia removal rate has reached 83.9%).

Further, considering that the types of catalyst metals are different between the catalyst used in Example 2 and the catalyst used in Example 5, comparing these, the catalyst using Ru as the catalyst metal (Example 5) It was found that the removal performance of ammonia is higher than that of the catalyst using Cu as the catalyst metal (Example 2) even if the amount of the catalyst metal carried is small (it is clear from Table 2). As described above, in Example 5, the maximum value of the removal rate of ammonia reached 92.9%). _{From the measurement data from the measurement lower limit temperature (Tlow} ) to the measurement upper limit temperature ( _High ) in the second heat treatment, the temperature at which the ammonia removal rate is 10% or more (sufficiently advanced). _{The lower limit (value of T 10} ) of the temperature indicating the ammonia purification activity) is 349 ° C. in the catalyst using Ru as the catalyst metal (Example 5), and in the catalyst using Cu as the catalyst metal (Example 2). Since the temperature was 408 ° C., it was also found that when Ru was used as the catalyst metal, the ability to oxidize and purify ammonia (catalytic activity) could be more sufficiently exhibited from a lower temperature.

(Calculation Examples 1 to 4: Trial calculation examples regarding the amount and volume of materials used)
Assuming an automobile loaded with a fuel cell that uses hydrogen as fuel, as a device for supplying hydrogen to the fuel cell, a feeder that supplies hydrogen as a raw material; and an ammonia reformer (reforms ammonia) (Means for generating hydrogen gas); A hydrogen purification device of either an adsorber (adsorption type hydrogen purification device) filled with an adsorbent or a catalyst-filled hydrogen purification device filled with a catalyst (ammonia selective oxidation catalyst). (It is assumed that when the catalyst-filled hydrogen purification device is used, oxygen is used for the catalytic reaction, so that an oxygen supply device is further provided). Then, when the ammonia (residue of the raw material) remaining in the reforming gas generated by the ammonia reformer is removed by using the hydrogen purification apparatus to obtain a purified gas, the purified gas (purification). Hydrogen required by calculating (simulating) the amount (g) and volume (L) of the material (adsorbent or catalyst) required to reduce the concentration of ammonia in the gas) to 0.1 ppm or less. The physique (inferred value) of the purification device was examined. In such a calculation, it was assumed that an ammonia reformer capable of reforming 99.9 mol% of ammonia (raw material) into hydrogen and nitrogen was used (reform of ammonia in the ammonia reformer). The quality efficiency was assumed to be 99.9 mol%). In addition, other matters (automobile performance, etc.) necessary for such calculation were calculated assuming the following.

<Car performance, etc.>
・ Fuel efficiency ( _{mileage per 1 kg of fuel (H 2} )): 100 km / kg-H ₂・ Annual mileage: 10,000 km ・ Vehicle life: 10 years ・ Fuel per day (H ₂₎ ) Usage amount: 270 g (calculated from the above assumed fuel consumption)
-Daily usage of the reformed raw material (ammonia): 1.5 kg (calculated from the assumed fuel consumption and the reforming efficiency of the reformer).

<Performance of adsorbent to be filled in adsorption type hydrogen purification device (adsorber)>
-Type of adsorbent: Assuming that zeolite is used-Adsorption capacity of adsorbent: Assumed that ammonia can be adsorbed up to 3% by mass with respect to the total amount of adsorbent (general saturated adsorption amount of ammonia in the above adsorbent) Adopted)
-Assumed packing density of adsorbent: 0.6 g / mL (general packing density is adopted from the above types of adsorbent).

<Performance of catalyst to be filled in catalyst-filled hydrogen purification equipment>
-Catalyst type: It is assumed that an ammonia selective oxidation catalyst in which a catalyst metal (Cu or Ru) is supported on β-zeolite is used.-Catalyst purification performance: Ammonia in gas (gas after contact) due to selective oxidation reaction It is assumed that a concentration of 0.1 ppm can be achieved (it is assumed that 0.12 g of ammonia can be removed per 1 g of catalyst in one day).
-Catalyst density: Assumed to be 0.6 g / mL (the same value as the above adsorbent is used).

Further, in such a calculation, an adsorbent (when the fixed adsorber is filled with the adsorbent) that uses the adsorbent without replacement or regeneration for 10 years is used as the adsorbent hydrogen purification device. Let the calculation result in the assumed case be the calculation example 1. In addition, it is assumed that the adsorbent is filled in a replaceable cartridge type adsorbent and replaced once a month, and it is assumed that the cartridge type adsorbent is used as an adsorption type hydrogen purification device. Let the result be calculation example 2. Further, when the adsorber is used while regenerating the adsorber once a day in an automobile by using two adsorbers filled with the adsorbent (on-board regenerative adsorber: two adsorbers while regenerating once a day). Calculation example 3 is a calculation result when it is assumed that the two adsorbers are used as an adsorption type hydrogen purification device (when the vessels are used alternately). Then, the calculation result on the assumption that a catalyst-filled hydrogen purification apparatus filled with an ammonia selective oxidation catalyst is used is referred to as Calculation Example 4. The calculation results are shown in Table 3.

As is clear from the calculation results shown in Table 3, it is necessary for calculation in a fixed type adsorber (adsorption type hydrogen purification device: calculation example 1) that is used without replacement or regeneration for 10 years. Since the amount of the adsorbent to be used is 18750 kg and the volume thereof is 31250 L, it can be seen that the physique of the hydrogen purification device cannot be reduced and it is difficult to reduce the size of the hydrogen purification device. .. In addition, it is necessary for calculation even when the replacement is performed once a month using an adsorber (adsorption type hydrogen purification device: calculation example 2) in which a replaceable cartridge is filled with an adsorbent. Since the amount of the adsorbent is 156 kg and the volume thereof is 260 L, it is understood that it is difficult to reduce the size of the hydrogen purification apparatus. On the other hand, when two adsorbers filled with the adsorbent are used and the adsorber is used while regenerating the adsorbent once a day in an automobile (adsorption type hydrogen purification device consisting of an on-board regenerative adsorber: calculation). In Example 3), the amount of the adsorbent required for calculation is 2.6 kg, and the volume is 4.3 L. Therefore, it is much smaller than the cases of Calculation Examples 1 and 2. It can be recognized that it can be made into a car, and it is considered possible to load it in an automobile. On the other hand, in the case of a hydrogen purification device (the catalyst-filled hydrogen purification device) in which an ammonia selective oxidation catalyst is used for purification of ammonia instead of an adsorbent (Calculation Example 4), the calculation is performed. Since the amount of catalyst required is 1.3 kg and the volume is 2.1 L, it is found that the volume of the hydrogen purification apparatus can be further reduced, and thus Calculation Examples 1 to 1 It can be seen that the device can be further miniaturized as compared with the device described in No. 3, and can be made into a small size suitable for loading an automobile or the like. From these results, when the ammonia selective oxidation catalyst is used for purification of ammonia, hydrogen is compared with the case where the adsorbent is used, for example, when it is assumed to be mounted on a vehicle. It can be seen that the purification capacity (ammonia removal performance) can be sufficiently improved, which is excellent in terms of miniaturization of the apparatus.

As described above, according to the present invention, it is possible to remove ammonia from the reformed gas containing ammonia and hydrogen at a sufficiently high removal rate, and the device is compact while having a sufficiently high hydrogen purification capacity. It is possible to provide an ammonia-reformed hydrogen supply device capable of sufficiently converting hydrogen, and an ammonia-reformed hydrogen supply method using the device. Therefore, the ammonia-modified hydrogen supply device of the present invention can be sufficiently miniaturized, and is particularly useful as, for example, a device for supplying hydrogen to a fuel cell loaded in an automobile. Is.

1 ... Ammonia reforming hydrogen supply device, 10 ... Raw material supply device, 11 ... Ammonia reformer, 12 ... Hydrogen purification device, 13 ... Oxygen supply device, 14a-14e ... Gas tube, 100 ... Reaction tube, 101 ... Catalyst , 102 ... Glass wool.

Claims (5)

A raw material feeder for supplying ammonia as a raw material,
An ammonia reformer for producing a reformed gas containing hydrogen by reforming the ammonia supplied from the raw material feeder, and
A hydrogen purification apparatus provided with an ammonia selective oxidation catalyst for oxidizing ammonia in the reforming gas supplied from the reformer.
An oxygen supply device for supplying oxygen to the hydrogen purification device and
And also
The ammonia selective oxidation catalyst is a catalyst comprising an acidic porous carrier and at least one catalyst metal selected from the group consisting of Cu and Ru, which is supported on the acidic porous carrier. Ammonia reformed hydrogen supply device. The ammonia-modified hydrogen supply device according to claim 1, wherein the acidic porous carrier is zeolite. Using the ammonia-modified hydrogen supply device according to claim 1 or 2, ammonia as a raw material is supplied from the raw material supply device to the ammonia reformer to generate the reformed gas, and then the reforming is performed. By supplying oxygen from the oxygen supply device to the hydrogen purification device while supplying gas from the ammonia reformer to the hydrogen purification device, the reforming gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst. A method for supplying hydrogen modified by ammonia, which comprises purifying hydrogen by oxidizing ammonia in the reformed gas and supplying the purified hydrogen. The ammonia-modified hydrogen supply method according to claim 3, wherein the temperature of the contact gas when the reformed gas and the oxygen are brought into contact with the ammonia selective oxidation catalyst is 350 ° C. to 750 ° C. A claim characterized in that the supply ratio of oxygen and ammonia when brought into contact with the ammonia selective oxidation catalyst is _{0.75 to 20 in terms of volume ratio ([oxygen (O 2} )] / [ammonia (NH _3)]). Item 3. The ammonia-modified hydrogen supply method according to Item 3.

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