JP2010094669A - Ammonia-decomposition catalyst, method of producing the same, and method of treating ammonia - Google Patents
Ammonia-decomposition catalyst, method of producing the same, and method of treating ammonia Download PDFInfo
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 289
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 139
- 239000003054 catalyst Substances 0.000 title claims abstract description 104
- 238000000354 decomposition reaction Methods 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 32
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 89
- 239000001257 hydrogen Substances 0.000 claims abstract description 49
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 49
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 44
- 150000004767 nitrides Chemical class 0.000 claims abstract description 43
- 229910052751 metal Inorganic materials 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims abstract description 33
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000007789 gas Substances 0.000 claims abstract description 28
- 239000002243 precursor Substances 0.000 claims abstract description 22
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 16
- 229910052723 transition metal Inorganic materials 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 150000003624 transition metals Chemical class 0.000 claims description 12
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 11
- 150000002910 rare earth metals Chemical class 0.000 claims description 11
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 10
- 229910052783 alkali metal Inorganic materials 0.000 claims description 10
- 150000001340 alkali metals Chemical class 0.000 claims description 10
- 229910017052 cobalt Inorganic materials 0.000 claims description 10
- 239000010941 cobalt Substances 0.000 claims description 10
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 10
- 229910052750 molybdenum Inorganic materials 0.000 claims description 10
- 239000011733 molybdenum Substances 0.000 claims description 10
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 9
- 229910052759 nickel Inorganic materials 0.000 claims description 9
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 150000002431 hydrogen Chemical class 0.000 claims description 7
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 239000011651 chromium Substances 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 6
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 6
- 229910052721 tungsten Inorganic materials 0.000 claims description 6
- 239000010937 tungsten Substances 0.000 claims description 6
- 229910052720 vanadium Inorganic materials 0.000 claims description 6
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 claims description 6
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 239000011572 manganese Substances 0.000 claims description 2
- 238000005121 nitriding Methods 0.000 abstract description 25
- 229910000510 noble metal Inorganic materials 0.000 abstract description 5
- NLSCHDZTHVNDCP-UHFFFAOYSA-N caesium nitrate Chemical compound [Cs+].[O-][N+]([O-])=O NLSCHDZTHVNDCP-UHFFFAOYSA-N 0.000 description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 26
- 238000002441 X-ray diffraction Methods 0.000 description 24
- 239000012153 distilled water Substances 0.000 description 24
- 239000007864 aqueous solution Substances 0.000 description 18
- 238000006243 chemical reaction Methods 0.000 description 15
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 13
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 8
- 239000000654 additive Substances 0.000 description 7
- 230000000996 additive effect Effects 0.000 description 7
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 7
- 229940010552 ammonium molybdate Drugs 0.000 description 7
- 235000018660 ammonium molybdate Nutrition 0.000 description 7
- 239000011609 ammonium molybdate Substances 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- QGUAJWGNOXCYJF-UHFFFAOYSA-N cobalt dinitrate hexahydrate Chemical compound O.O.O.O.O.O.[Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O QGUAJWGNOXCYJF-UHFFFAOYSA-N 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 238000009835 boiling Methods 0.000 description 5
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 229910044991 metal oxide Inorganic materials 0.000 description 5
- 150000004706 metal oxides Chemical class 0.000 description 5
- -1 alkaline earth metal basic compound Chemical class 0.000 description 4
- 239000000571 coke Substances 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 2
- 239000007900 aqueous suspension Substances 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- MFUVDXOKPBAHMC-UHFFFAOYSA-N magnesium;dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MFUVDXOKPBAHMC-UHFFFAOYSA-N 0.000 description 2
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000011206 ternary composite Substances 0.000 description 2
- 229910000314 transition metal oxide Inorganic materials 0.000 description 2
- 229910001868 water Inorganic materials 0.000 description 2
- ZHJGWYRLJUCMRT-UHFFFAOYSA-N 5-[6-[(4-methylpiperazin-1-yl)methyl]benzimidazol-1-yl]-3-[1-[2-(trifluoromethyl)phenyl]ethoxy]thiophene-2-carboxamide Chemical compound C=1C=CC=C(C(F)(F)F)C=1C(C)OC(=C(S1)C(N)=O)C=C1N(C1=C2)C=NC1=CC=C2CN1CCN(C)CC1 ZHJGWYRLJUCMRT-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- QQSDFKXDNYDAFU-UHFFFAOYSA-N [O--].[Ni++].[La+3] Chemical compound [O--].[Ni++].[La+3] QQSDFKXDNYDAFU-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- YMKHJSXMVZVZNU-UHFFFAOYSA-N manganese(2+);dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YMKHJSXMVZVZNU-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- AOPCKOPZYFFEDA-UHFFFAOYSA-N nickel(2+);dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O AOPCKOPZYFFEDA-UHFFFAOYSA-N 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- 239000010815 organic waste Substances 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Abstract
Description
本発明は、アンモニアを窒素と水素とに分解する触媒およびその製造方法、ならびに、この触媒を用いたアンモニア処理方法に関する。 The present invention relates to a catalyst for decomposing ammonia into nitrogen and hydrogen, a method for producing the catalyst, and an ammonia treatment method using the catalyst.
アンモニアは、臭気性、特に刺激性の悪臭を有するので、ガス中に臭気閾値以上含まれる場合には、これを処理することが必要となる。そこで、従来から様々なアンモニア処理方法が検討されてきた。例えば、アンモニアを酸素と接触させて窒素と水とに酸化する方法、アンモニアを窒素と水素とに分解する方法などが提案されている。 Since ammonia has an odorous property, particularly an irritating malodor, it is necessary to treat it when the gas contains an odor threshold value or more. Therefore, various ammonia treatment methods have been conventionally studied. For example, a method in which ammonia is brought into contact with oxygen and oxidized into nitrogen and water, and a method in which ammonia is decomposed into nitrogen and hydrogen have been proposed.
例えば、特許文献１には、コークス炉から生じるアンモニアを窒素と水とに酸化するにあたり、例えば、白金−アルミナ触媒、マンガン−アルミナ触媒、コバルト−アルミナ触媒などを用いると共に、コークス炉から生じるアンモニアを窒素と水素とに分解するにあたり、例えば、鉄−アルミナ触媒、ニッケル−アルミナ触媒などを用いるアンモニア処理方法が開示されている。しかし、このアンモニア処理方法は、ＮＯｘが副生することが多いことから、新たにＮＯｘ処理設備が必要となるので、好ましくない。 For example, Patent Document 1 discloses that, for example, a platinum-alumina catalyst, a manganese-alumina catalyst, a cobalt-alumina catalyst, and the like are used to oxidize ammonia generated from a coke oven to nitrogen and water, and ammonia generated from the coke oven is used. In decomposing into nitrogen and hydrogen, for example, an ammonia treatment method using an iron-alumina catalyst, a nickel-alumina catalyst, or the like is disclosed. However, this ammonia treatment method is not preferable because NOx is often produced as a by-product and a new NOx treatment facility is required.
また、特許文献２には、有機性廃棄物を処理する工程から生じるアンモニアを窒素と水素とに分解するにあたり、アルミナ、シリカ、チタニア、ジルコニアなどの金属酸化物担体上にニッケルまたはニッケル酸化物を担持させ、さらにアルカリ土類金属およびランタノイド元素の少なくとも一方を金属または酸化物の形で添加した触媒を用いるアンモニア処理方法が開示されている。しかし、このアンモニア処理方法は、アンモニア分解率が低く、実用的ではない。 Patent Document 2 discloses that nickel or nickel oxide is deposited on a metal oxide carrier such as alumina, silica, titania, zirconia in decomposing ammonia generated from a process of treating organic waste into nitrogen and hydrogen. An ammonia treatment method using a catalyst that is supported and further added with at least one of an alkaline earth metal and a lanthanoid element in the form of a metal or an oxide is disclosed. However, this ammonia treatment method has a low ammonia decomposition rate and is not practical.
さらに、特許文献３には、コークス炉から生じるアンモニアを窒素と水素とに分解するにあたり、アルミナ担体上のルテニウムにアルカリ金属またはアルカリ土類金属の塩基性化合物を添加した触媒を用いるアンモニア処理方法が開示されている。このアンモニア処理方法は、従来の鉄−アルミナなどの触媒に比べて、より低温でアンモニアを分解できるという利点があるにもかかわらず、活性金属種として、希少貴金属であるルテニウムを用いているので、コスト面で大きな問題を抱えており、実用的ではない。 Further, Patent Document 3 discloses an ammonia treatment method using a catalyst in which an alkali metal or an alkaline earth metal basic compound is added to ruthenium on an alumina support in decomposing ammonia generated from a coke oven into nitrogen and hydrogen. It is disclosed. This ammonia treatment method uses ruthenium, which is a rare noble metal, as an active metal species, despite the advantage that ammonia can be decomposed at a lower temperature than a conventional catalyst such as iron-alumina. It has a big problem in cost and is not practical.
その他、アンモニアの分解によって回収された水素を燃料電池用の水素源として利用することが検討されているが、この場合は、高純度の水素を得ることが必要となる。これまでに提案されてきたアンモニア分解触媒を用いて、高純度の水素を得ようとすると、非常に高い反応温度が必要となり、あるいは、高価な触媒を多量に用いる必要があるという問題があった。 In addition, it has been studied to use hydrogen recovered by decomposition of ammonia as a hydrogen source for a fuel cell. In this case, it is necessary to obtain high-purity hydrogen. When trying to obtain high-purity hydrogen using the ammonia decomposition catalysts proposed so far, there is a problem that a very high reaction temperature is required or a large amount of an expensive catalyst needs to be used. .
このような問題を解決するために、アンモニアを比較的低温（約４００〜５００℃）で分解できる触媒として、例えば、特許文献４には、鉄−セリア複合体が開示され、特許文献５には、ニッケル−酸化ランタン／アルミナ、ニッケル−イットリア／アルミナ、ニッケル−セリア／アルミナの３元系複合体が開示され、非特許文献１には、鉄−セリア／ジルコニアの３元系複合体が開示されている。 In order to solve such a problem, as a catalyst capable of decomposing ammonia at a relatively low temperature (about 400 to 500 ° C.), for example, Patent Document 4 discloses an iron-ceria complex, and Patent Document 5 discloses Nickel-lanthanum oxide / alumina, nickel-yttria / alumina, nickel-ceria / alumina ternary composites are disclosed, and Non-Patent Document 1 discloses an iron-ceria / zirconia ternary composite. ing.
しかし、これらの触媒は、いずれも、処理ガスのアンモニア濃度が低い（具体的には、特許文献４は５体積％、特許文献５は５０体積％）か、あるいは、アンモニアを基準とした空間速度が低い（具体的には、特許文献４は６４２ｈ−１、特許文献５は１，０００ｈ−１、非特許文献１は４３０ｈ−１）といった条件下で、アンモニア分解率を測定しているので、たとえ、アンモニア分解率が比較的低温で１００％であるからと言っても、必ずしも触媒性能が高いわけではない。
However, any of these catalysts has a low ammonia concentration in the processing gas (specifically, 5% by volume in
このように、従来のアンモニア分解触媒は、いずれも、アンモニアを比較的低温で、かつ、高い空間速度で効率よく分解して高純度の水素を取得することはできないという問題があった。 As described above, each of the conventional ammonia decomposition catalysts has a problem that it is not possible to obtain high-purity hydrogen by efficiently decomposing ammonia at a relatively low temperature and at a high space velocity.
上述した状況の下、本発明が解決すべき課題は、コスト面で実用上の問題がある貴金属を用いることなく、低濃度から高濃度までの広範囲なアンモニア濃度域において、アンモニアを比較的低温で、かつ、高い空間速度で窒素と水素とに効率よく分解して高純度の水素を取得できる触媒およびその製造方法、ならびに、アンモニア処理方法を提供することにある。 Under the circumstances described above, the problem to be solved by the present invention is that ammonia is used at a relatively low temperature in a wide ammonia concentration range from a low concentration to a high concentration without using a noble metal that has practical problems in terms of cost. Another object of the present invention is to provide a catalyst that can be efficiently decomposed into nitrogen and hydrogen at a high space velocity to obtain high purity hydrogen, a method for producing the catalyst, and an ammonia treatment method.
本発明者らは、種々検討の結果、触媒活性成分に特定の遷移金属（貴金属を除く）の窒化物を含有させれば、アンモニアを比較的低温で、かつ、高い空間速度で窒素と水素とに効率よく分解して高純度の水素を取得できる触媒が得られることを見出して、本発明を完成した。 As a result of various studies, the inventors of the present invention have made it possible to contain ammonia at a relatively low temperature and at a high space velocity by adding a nitride of a specific transition metal (excluding noble metals) to the catalytically active component. The present invention was completed by discovering that a catalyst capable of obtaining high-purity hydrogen by efficiently decomposing was obtained.
すなわち、本発明は、アンモニアを窒素と水素とに分解する触媒であって、触媒活性成分が金属窒化物を含有することを特徴とするアンモニア分解触媒を提供する。本発明のアンモニア分解触媒において、前記触媒活性成分は、モリブデン、コバルト、ニッケル、鉄、バナジウム、タングステン、クロムおよびマンガンよりなる群から選択される少なくとも１種の遷移金属の窒化物を含有することが好ましく、さらに、アルカリ金属、アルカリ土類金属および希土類金属よりなる群から選択される少なくとも１種を含有していてもよい。 That is, the present invention provides an ammonia decomposition catalyst characterized in that ammonia is decomposed into nitrogen and hydrogen, and the catalytically active component contains a metal nitride. In the ammonia decomposition catalyst of the present invention, the catalytically active component contains a nitride of at least one transition metal selected from the group consisting of molybdenum, cobalt, nickel, iron, vanadium, tungsten, chromium and manganese. Preferably, it may further contain at least one selected from the group consisting of alkali metals, alkaline earth metals and rare earth metals.
また、本発明は、金属窒化物の前駆体をアンモニアまたは窒素−水素混合ガスで窒化処理して、前記金属窒化物を形成することを特徴とするアンモニア分解触媒の製造方法を提供する。本発明によるアンモニア分解触媒の製造方法において、前記前駆体は、モリブデン、コバルト、ニッケル、鉄、バナジウム、タングステン、クロムおよびマンガンよりなる群から選択される少なくとも１種の遷移金属またはその化合物であることが好ましい。また、前記前駆体に、さらに、アルカリ金属、アルカリ土類金属および希土類金属よりなる群から選択される少なくとも１種の化合物を添加してもよい。 The present invention also provides a method for producing an ammonia decomposition catalyst, characterized in that a metal nitride precursor is nitrided with ammonia or a nitrogen-hydrogen mixed gas to form the metal nitride. In the method for producing an ammonia decomposition catalyst according to the present invention, the precursor is at least one transition metal selected from the group consisting of molybdenum, cobalt, nickel, iron, vanadium, tungsten, chromium, and manganese, or a compound thereof. Is preferred. Further, at least one compound selected from the group consisting of alkali metals, alkaline earth metals and rare earth metals may be added to the precursor.
さらに、本発明は、上記のようなアンモニア分解触媒を用いて、アンモニアを含有するガスを処理して、前記アンモニアを窒素と水素とに分解して水素を取得することを特徴とするアンモニア処理方法を提供する。 Furthermore, the present invention is an ammonia treatment method characterized in that the ammonia-decomposing catalyst as described above is used to treat a gas containing ammonia to obtain hydrogen by decomposing the ammonia into nitrogen and hydrogen. I will provide a.
本発明によれば、貴金属を用いることなく、低濃度から高濃度までの広範囲なアンモニア濃度域において、アンモニアを比較的低温で、かつ、高い空間速度で窒素と水素とに効率よく分解して高純度の水素を取得できる触媒、この触媒を簡便に製造する方法、ならびに、この触媒を用いて、アンモニアを窒素と水素とに分解して水素を取得する方法が提供される。 According to the present invention, ammonia is efficiently decomposed into nitrogen and hydrogen at a relatively low temperature and at a high space velocity in a wide ammonia concentration range from a low concentration to a high concentration without using noble metals. Provided are a catalyst capable of obtaining pure hydrogen, a method for easily producing the catalyst, and a method for obtaining hydrogen by decomposing ammonia into nitrogen and hydrogen using the catalyst.
≪アンモニア分解触媒≫
本発明のアンモニア分解触媒（以下「本発明の触媒」ということがある）は、アンモニアを窒素と水素とに分解する触媒であって、触媒活性成分が金属窒化物を含有することを特徴とする。
≪Ammonia decomposition catalyst≫
The ammonia decomposition catalyst of the present invention (hereinafter sometimes referred to as “the catalyst of the present invention”) is a catalyst that decomposes ammonia into nitrogen and hydrogen, and the catalytically active component contains a metal nitride. .
本発明の触媒において、金属窒化物は、遷移金属の窒化物であれば、特に限定されるものではないが、例えば、周期律表の第４〜８族に属する遷移金属の窒化物が挙げられる。これらの金属窒化物のうち、モリブデン、コバルト、ニッケル、鉄、バナジウム、タングステン、クロムおよびマンガンよりなる群から選択される少なくとも１種の遷移金属の窒化物であることが好ましく、モリブデン、コバルト、ニッケルおよび鉄よりなる群から選択される少なくとも１種の遷移金属の窒化物がより好ましい。 In the catalyst of the present invention, the metal nitride is not particularly limited as long as it is a transition metal nitride, and examples thereof include transition metal nitrides belonging to Groups 4 to 8 of the periodic table. . Among these metal nitrides, it is preferably a nitride of at least one transition metal selected from the group consisting of molybdenum, cobalt, nickel, iron, vanadium, tungsten, chromium, and manganese, and molybdenum, cobalt, nickel And nitrides of at least one transition metal selected from the group consisting of iron and iron are more preferred.
金属窒化物は、それ自体を用いてもよいし、その前駆体をアンモニアガスまたは窒素−水素混合ガスで窒化処理することにより形成してもよい。金属窒化物の前駆体としては、遷移金属、その酸化物および塩などが挙げられる。これらの前駆体のうち、遷移金属の酸化物が好ましい。遷移金属については、上記したとおりである。 The metal nitride may be used by itself, or may be formed by nitriding the precursor with ammonia gas or a nitrogen-hydrogen mixed gas. Examples of the metal nitride precursor include transition metals, oxides and salts thereof. Of these precursors, transition metal oxides are preferred. The transition metal is as described above.
窒化処理により触媒活性成分が窒化物に変化した割合は、Ｘ線回折で触媒の結晶構造を調べることにより確認することができる。触媒活性成分の全部が窒化物に変化していることが好ましいが、必ずしもその必要はなく、触媒活性成分の一部が窒化物に変化している場合であっても、充分な触媒活性を有する。触媒中における窒化物の割合（Ｘ線回折パターンにおける酸化物のピークと窒化物のピークとの積算値の和を１００％としたときの割合）は、好ましくは３％以上、より好ましくは５％以上である。 The ratio of the catalytically active component changed to nitride by the nitriding treatment can be confirmed by examining the crystal structure of the catalyst by X-ray diffraction. Although it is preferable that all of the catalytically active component is changed to nitride, it is not always necessary, and even if a part of the catalytically active component is changed to nitride, it has sufficient catalytic activity. . The ratio of nitride in the catalyst (ratio when the sum of integrated values of oxide peaks and nitride peaks in the X-ray diffraction pattern is 100%) is preferably 3% or more, more preferably 5% That's it.
本発明の触媒において、触媒活性成分は、さらに、アルカリ金属、アルカリ土類金属および希土類金属よりなる群から選択される少なくとも１種を含有していてもよい。これらの添加成分のうち、アルカリ金属が好ましい。 In the catalyst of the present invention, the catalytically active component may further contain at least one selected from the group consisting of alkali metals, alkaline earth metals, and rare earth metals. Of these additive components, alkali metals are preferred.
これらの添加成分の量（酸化物換算）は、金属窒化物に対して、好ましくは０〜５０質量％、より好ましくは０．２〜２０質量％である。なお、酸化物換算は、希土類金属は３価金属の酸化物、アルカリ金属は１価金属の酸化物、アルカリ土類金属は２価金属の酸化物として換算する。 The amount of these additive components (oxide conversion) is preferably 0 to 50% by mass, more preferably 0.2 to 20% by mass, based on the metal nitride. In terms of oxide conversion, rare earth metals are converted as trivalent metal oxides, alkali metals as monovalent metal oxides, and alkaline earth metals as divalent metal oxides.
＜物性＞
本発明の触媒は、比表面積が好ましくは１〜３００ｍ２／ｇ、より好ましくは５〜２６０ｍ２／ｇ、さらに好ましくは１８〜２００ｍ２／ｇである。
<Physical properties>
The specific surface area of the catalyst of the present invention is preferably 1 to 300 m 2 / g, more preferably 5 to 260 m 2 / g, still more preferably 18 to 200 m 2 / g.
＜触媒の形状＞
本発明の触媒は、触媒活性成分をそのまま触媒とするか、あるいは、従来公知の方法を用いて、触媒活性成分を担体に担持してもよい。担体としては、特に限定されるものではないが、例えば、アルミナ、シリカ、チタニア、ジルコニア、セリアなどの金属酸化物が挙げられる。
<Catalyst shape>
In the catalyst of the present invention, the catalytically active component may be used as it is, or the catalytically active component may be supported on a carrier by a conventionally known method. The support is not particularly limited, and examples thereof include metal oxides such as alumina, silica, titania, zirconia, and ceria.
本発明の触媒は、従来公知の方法を用いて、所望の形状に成形して用いてもよい。触媒の形状は、特に限定されるものではなく、例えば、粒状、球状、ペレット状、破砕状、サドル状、リング状、ハニカム状、モノリス状、網状、円柱状、円筒状などが挙げられる。 The catalyst of the present invention may be molded into a desired shape using a conventionally known method. The shape of the catalyst is not particularly limited, and examples thereof include granular, spherical, pellet-shaped, crushed, saddle-shaped, ring-shaped, honeycomb-shaped, monolith-shaped, net-shaped, columnar, cylindrical, and the like.
また、本発明の触媒は、構造体の表面に層状にコートして用いてもよい。構造体としては、特に限定されるものではないが、例えば、コージェライト、ムライト、炭化珪素、アルミナ、シリカ、チタニア、ジルコニア、セリアなどのセラミックスからなる構造体；フェライト系ステンレスなどの金属からなる構造体；などが挙げられる。構造体の形状としては、特に限定されるものではないが、例えば、ハニカム状、コルゲート状、網状、円柱状、円筒状などが挙げられる。 Further, the catalyst of the present invention may be used by coating the surface of the structure in layers. The structure is not particularly limited. For example, a structure made of a ceramic such as cordierite, mullite, silicon carbide, alumina, silica, titania, zirconia, and ceria; a structure made of a metal such as ferritic stainless steel Body; and the like. The shape of the structure is not particularly limited, and examples thereof include a honeycomb shape, a corrugated shape, a net shape, a columnar shape, and a cylindrical shape.
≪アンモニア分解触媒の製造方法≫
以下に、本発明のアンモニア分解触媒を製造する方法の好適な具体例を示すが、本発明の課題が達成される限り、下記の製造方法に限定されるものではない。
≪Method for producing ammonia decomposition catalyst≫
Hereinafter, preferred specific examples of the method for producing the ammonia decomposition catalyst of the present invention will be shown, but the present invention is not limited to the following production method as long as the object of the present invention is achieved.
（１）金属窒化物の前駆体をアンモニアガスで窒化処理する方法；
（２）金属窒化物の前駆体を窒素−水素混合ガスで窒化処理する方法；
（３）金属窒化物の前駆体に、添加成分を混合して含有させた後、アンモニアガスまたは窒素−水素混合ガスで窒化処理する方法；
（４）金属窒化物の前駆体に、添加成分を含有する水溶液または水性懸濁液を混合し、乾燥させ、必要に応じて、焼成した後、アンモニアガスまたは窒素−水素混合ガスで窒化処理する方法；
（５）金属窒化物の前駆体をアンモニアガスまたは窒素−水素混合ガスで窒化処理した後、添加成分を混合して含有させる方法；
（６）金属窒化物の前駆体をアンモニアガスまたは窒素−水素混合ガスで窒化処理した後、添加成分を含有する水溶液または水性懸濁液を混合し、乾燥させ、必要に応じて、さらに焼成する方法。
(1) A method of nitriding a metal nitride precursor with ammonia gas;
(2) A method of nitriding a metal nitride precursor with a nitrogen-hydrogen mixed gas;
(3) A method in which an additive component is mixed and contained in a metal nitride precursor and then nitriding with ammonia gas or a nitrogen-hydrogen mixed gas;
(4) An aqueous solution or aqueous suspension containing an additive component is mixed with the precursor of the metal nitride, dried, and fired as necessary, followed by nitriding with ammonia gas or nitrogen-hydrogen mixed gas. Method;
(5) A method in which a precursor of a metal nitride is nitrided with ammonia gas or a nitrogen-hydrogen mixed gas and then mixed with an additive component;
(6) After nitriding the precursor of metal nitride with ammonia gas or nitrogen-hydrogen mixed gas, an aqueous solution or aqueous suspension containing the additive component is mixed, dried, and further fired as necessary. Method.
本発明によるアンモニア分解触媒の製造方法（以下「本発明の製造方法」ということがある）は、例えば、金属窒化物の前駆体をアンモニアガスまたは窒素−水素混合ガスで窒化処理して、前記金属窒化物を形成することを特徴とする。 The method for producing an ammonia decomposition catalyst according to the present invention (hereinafter sometimes referred to as “the production method of the present invention”) includes, for example, nitriding a metal nitride precursor with ammonia gas or a nitrogen-hydrogen mixed gas, and Nitride is formed.
金属窒化物の前駆体は、モリブデン、コバルト、ニッケル、鉄、バナジウム、タングステン、クロムおよびマンガンよりなる群から選択される少なくとも１種の遷移金属またはその化合物であることが好ましい。また、金属窒化物の前駆体に、さらに、アルカリ金属、アルカリ土類金属および希土類金属よりなる群から選択される少なくとも１種の化合物を添加してもよい。これらの添加成分のうち、アルカリ金属が好ましい。 The metal nitride precursor is preferably at least one transition metal selected from the group consisting of molybdenum, cobalt, nickel, iron, vanadium, tungsten, chromium, and manganese, or a compound thereof. Further, at least one compound selected from the group consisting of alkali metals, alkaline earth metals, and rare earth metals may be added to the metal nitride precursor. Of these additive components, alkali metals are preferred.
金属窒化物は、それ自体を用いるか、あるいは、その前駆体をアンモニアガスまたは窒素−水素混合ガスで窒化処理することにより形成する。金属窒化物の前駆体としては、遷移金属、その酸化物および塩などが挙げられる。これらの前駆体のうち、遷移金属の酸化物が好ましい。遷移金属については、上記したとおりである。 The metal nitride is used by itself, or is formed by nitriding the precursor with ammonia gas or a nitrogen-hydrogen mixed gas. Examples of the metal nitride precursor include transition metals, oxides and salts thereof. Of these precursors, transition metal oxides are preferred. The transition metal is as described above.
窒化処理の温度は、通常は３００〜８００℃、好ましくは４００〜７５０℃、より好ましくは５００〜７２０℃である。アンモニアを用いる場合、アンモニアの濃度は、好ましくは１０〜１００体積％、より好ましくは５０〜１００体積％である。窒素−水素混合ガスを用いる場合、窒素の濃度は、好ましくは２〜９５体積％、より好ましくは２０〜９０体積％である。水素の濃度は、好ましくは５〜９８体積％、より好ましくは１０〜８０体積％である。 The temperature of the nitriding treatment is usually 300 to 800 ° C, preferably 400 to 750 ° C, more preferably 500 to 720 ° C. When ammonia is used, the concentration of ammonia is preferably 10 to 100% by volume, more preferably 50 to 100% by volume. When a nitrogen-hydrogen mixed gas is used, the concentration of nitrogen is preferably 2 to 95% by volume, more preferably 20 to 90% by volume. The concentration of hydrogen is preferably 5 to 98% by volume, more preferably 10 to 80% by volume.
ガスの流量（体積）は、アンモニアまたは窒素−水素混合ガスのいずれの場合も、１分間あたり、触媒の体積に対して、好ましくは８０〜２５０倍、より好ましくは１００〜２００倍である。 The flow rate (volume) of the gas is preferably 80 to 250 times, more preferably 100 to 200 times the volume of the catalyst per minute in either case of ammonia or nitrogen-hydrogen mixed gas.
なお、窒化処理に先立って、窒素を流しながら３００〜４００℃まで昇温することがより好ましい。この場合、窒素の流量（体積）は、１分間あたり、触媒の体積に対して、好ましくは５０〜１２０倍、より好ましくは６０〜１００倍である。 Prior to nitriding treatment, it is more preferable to raise the temperature to 300 to 400 ° C. while flowing nitrogen. In this case, the flow rate (volume) of nitrogen is preferably 50 to 120 times, more preferably 60 to 100 times the volume of the catalyst per minute.
≪アンモニア処理方法≫
本発明のアンモニア処理方法は、上記のようなアンモニア分解触媒を用いて、アンモニアを含有するガスを処理して、前記アンモニアを窒素と水素とに分解して取得することを特徴とする。処理対象となる「アンモニアを含有するガス」としては、特に限定されるものではないが、アンモニアガスやアンモニア含有ガスだけでなく、尿素などのように熱分解によりアンモニアを生じる物質を含有するガスであってもよい。また、アンモニアを含有するガスは、触媒毒にならない程度であれば、他の成分を含有していてもよい。
≪Ammonia treatment method≫
The ammonia treatment method of the present invention is characterized in that a gas containing ammonia is treated by using the ammonia decomposition catalyst as described above, and the ammonia is decomposed into nitrogen and hydrogen. The “gas containing ammonia” to be treated is not particularly limited, but includes not only ammonia gas and ammonia-containing gas but also gas containing a substance that generates ammonia by thermal decomposition such as urea. There may be. Moreover, the gas containing ammonia may contain other components as long as it does not become a catalyst poison.
触媒あたりの「アンモニアを含有するガス」の流量は、空間速度で、好ましくは１，０００〜２００，０００ｈ−１、より好ましくは２，０００〜１５０，０００ｈ−１、さらに好ましくは３，０００〜１００，０００ｈ−１である。ここで、触媒あたりの「アンモニアを含有するガス」の流量とは、触媒を反応器に充填した際に触媒が占める体積あたりの単位時間あたりに触媒を通過する「アンモニアを含有するガス」の体積を意味する。 The flow rate of the “gas containing ammonia” per catalyst is a space velocity, preferably 1,000 to 200,000 h −1 , more preferably 2,000 to 150,000 h −1 , more preferably 3,000 to 3,000. 100,000h- 1 . Here, the flow rate of the “gas containing ammonia” per catalyst means the volume of the “gas containing ammonia” passing through the catalyst per unit time per volume occupied by the catalyst when the catalyst is charged into the reactor. Means.
反応温度は、好ましくは１８０〜９５０℃、より好ましくは３００〜９００℃、さらに好ましくは４００〜８００℃である。反応圧力は、好ましくは０．００２〜２ＭＰａ、より好ましくは０．００４〜１ＭＰａである。 Reaction temperature becomes like this. Preferably it is 180-950 degreeC, More preferably, it is 300-900 degreeC, More preferably, it is 400-800 degreeC. The reaction pressure is preferably 0.002 to 2 MPa, more preferably 0.004 to 1 MPa.
本発明のアンモニア処理方法によれば、アンモニアを分解して得られた窒素および水素を、従来公知の方法を用いて、窒素と水素とに分離することにより、高純度の水素を取得することができる。 According to the ammonia treatment method of the present invention, high-purity hydrogen can be obtained by separating nitrogen and hydrogen obtained by decomposing ammonia into nitrogen and hydrogen using a conventionally known method. it can.
以下、実験例を挙げて本発明をより具体的に説明するが、本発明はもとより下記の実験例により制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも可能であり、それらはいずれも本発明の技術的範囲に包含される。 Hereinafter, the present invention will be described more specifically with reference to experimental examples.However, the present invention is not limited by the following experimental examples, and appropriate modifications are made within a range that can meet the purpose described above and below. Any of these can be carried out and are included in the technical scope of the present invention.
なお、Ｘ線回折測定には、Ｘ線回折装置（製品名「ＲＩＮＴ−２４００」、株式会社リガク製）を用いた。Ｘ線源には、ＣｕＫα（０．１５４ｎｍ）を用い、測定条件として、Ｘ線出力５０ｋＶ、３００ｍＡ、発散スリット１．０ｍｍ、発散縦制限スリット１０ｍｍで、スキャンスピード毎分５度、サンプリング幅０．０２度、走査範囲５〜９０度で実施した。 An X-ray diffractometer (product name “RINT-2400”, manufactured by Rigaku Corporation) was used for the X-ray diffraction measurement. CuKα (0.154 nm) was used as the X-ray source. The measurement conditions were an X-ray output of 50 kV, 300 mA, a divergence slit of 1.0 mm, a divergence length limit slit of 10 mm, a scan speed of 5 degrees per minute, and a sampling width of 0. The scanning was performed at 02 degrees and a scanning range of 5 to 90 degrees.
≪実験例１≫
硝酸コバルト六水和物８０．００ｇを蒸留水４００．００ｇに溶解させた。別途、沸騰させた蒸留水２５０ｇにモリブデン酸アンモニウム４８．５３ｇを徐々に添加して溶解させた。両方の水溶液を混合した後、加熱攪拌し、蒸発乾固させた。得られた固形物を１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。Ｘ線回折測定により、α−ＣｏＭｏＯ４であることを確認した（表１を参照）。なお、表１に示すピークは、すべて、ＣｏＭｏＯ４由来のピークである。
«Experimental example 1»
80.00 g of cobalt nitrate hexahydrate was dissolved in 400.00 g of distilled water. Separately, 48.53 g of ammonium molybdate was gradually added and dissolved in 250 g of boiling distilled water. After mixing both aqueous solutions, it was heated and stirred and evaporated to dryness. The obtained solid was dried at 120 ° C. for 10 hours, calcined at 350 ° C. for 5 hours under a nitrogen stream, and calcined at 500 ° C. for 3 hours under an air stream. It was confirmed to be α-CoMoO 4 by X-ray diffraction measurement (see Table 1). In addition, all the peaks shown in Table 1 are peaks derived from CoMoO 4 .
さらに、ＳＵＳ３１６製の反応管に、α−ＣｏＭｏＯ４を０．５〜１．０ｍＬ充填し、窒素ガス（以下「窒素」と略す）３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニアガス（以下「アンモニア」と略す）５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「ＣｏＭｏＯ４」と表示する）を得た。Ｘ線回折測定により、金属窒化物が形成されていることを確認した（表２を参照）。なお、表２に示すピークのうち、ピーク番号３はＭｏ由来であると思われるが、それ以外は、すべて、Ｃｏ３Ｍｏ３Ｎ由来のピークである。 Furthermore, 0.5-1.0 mL of α-CoMoO 4 was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30-50 mL / min of nitrogen gas (hereinafter referred to as “nitrogen”). Next, while flowing ammonia gas (hereinafter abbreviated as “ammonia”) at 50 to 100 mL / min, the temperature was raised to 700 ° C., and the treatment was held at 700 ° C. for 5 hours (nitriding treatment). CoMoO 4 ”). X-ray diffraction measurement confirmed that metal nitride was formed (see Table 2). Of the peaks shown in Table 2, peak number 3 seems to be derived from Mo, but all other peaks are peaks derived from Co 3 Mo 3 N.
≪実験例２≫
硝酸コバルト六水和物８０．００ｇを蒸留水４００．００ｇに溶解させた。別途、沸騰させた蒸留水２５０ｇにモリブデン酸アンモニウム４８．５３ｇを徐々に添加して溶解させた。両方の水溶液を混合した後、加熱攪拌し、蒸発乾固させた。得られた固形物を１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。Ｘ線回折測定により、α−ＣｏＭｏＯ４であることを確認した。
«Experimental example 2»
80.00 g of cobalt nitrate hexahydrate was dissolved in 400.00 g of distilled water. Separately, 48.53 g of ammonium molybdate was gradually added and dissolved in 250 g of boiling distilled water. After mixing both aqueous solutions, it was heated and stirred and evaporated to dryness. The obtained solid was dried at 120 ° C. for 10 hours, calcined at 350 ° C. for 5 hours under a nitrogen stream, and calcined at 500 ° C. for 3 hours under an air stream. It was confirmed to be α-CoMoO 4 by X-ray diffraction measurement.
次いで、硝酸セシウム０．０８９ｇを蒸留水３．２３ｇに溶解させた。この水溶液を、α−ＣｏＭｏＯ４ ６．００ｇに滴下して均一に浸透させ、９０℃で１０時間乾燥させた後、Ｘ線回折測定により、α−ＣｏＭｏＯ４であることを確認した（表３を参照）。なお、表３に示すピークは、すべて、ＣｏＭｏＯ４由来のピークである。ただし、Ｃｓを添加したことにより、結晶格子の歪みで、２θの値には、ずれが生じている。 Next, 0.089 g of cesium nitrate was dissolved in 3.23 g of distilled water. This aqueous solution was dropped into 6.00 g of α-CoMoO 4 and uniformly infiltrated, dried at 90 ° C. for 10 hours, and then confirmed to be α-CoMoO 4 by X-ray diffraction measurement (Table 3 reference). In addition, all the peaks shown in Table 3 are peaks derived from CoMoO 4 . However, the addition of Cs causes a shift in the value of 2θ due to distortion of the crystal lattice.
さらに、ＳＵＳ３１６製の反応管に、Ｃｓを含むα−ＣｏＭｏＯ４を０．５〜１．０ｍＬ充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「１％Ｃｓ−ＣｏＭｏＯ４」と表示する）を得た。Ｘ線回折測定により、金属窒化物が形成されていることを確認した（表４を参照）。なお、表４に示すピークのうち、ピーク番号４はＭｏ由来であると思われるが、それ以外は、すべて、Ｃｏ３Ｍｏ３Ｎ由来のピークである。ただし、Ｃｓを添加したことにより、結晶格子の歪みで、２θの値には、ずれが生じている。 Furthermore, 0.5-1.0 mL of α-CoMoO 4 containing Cs was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30-50 mL / min of nitrogen. Next, while flowing ammonia at 50 to 100 mL / min, the temperature was raised to 700 ° C., and a treatment (nitriding treatment) was performed at 700 ° C. for 5 hours to display an ammonia decomposition catalyst (hereinafter, “1% Cs—CoMoO 4 ”). Obtained). X-ray diffraction measurement confirmed that metal nitride was formed (see Table 4). In addition, although the peak number 4 seems to be Mo origin among the peaks shown in Table 4, all others are peaks derived from Co 3 Mo 3 N. However, the addition of Cs causes a shift in the value of 2θ due to distortion of the crystal lattice.
≪実験例３≫
実験例２において、硝酸セシウム０．０８９ｇを蒸留水３．２３ｇに溶解させた水溶液に代えて、硝酸セシウム０．１８ｇを蒸留水３．２１ｇに溶解させた水溶液を用いたこと以外は、実験例２と同様にして、アンモニア分解触媒（以下「２％Ｃｓ−ＣｏＭｏＯ４」と表示する）を得た。なお、硝酸セシウムを均一に浸透させ、９０℃で１０時間乾燥させた後の状態は、Ｘ線回折測定により、α−ＣｏＭｏＯ４であることを確認した（表５を参照）。なお、表５に示すピークは、すべて、ＣｏＭｏＯ４由来のピークである。
«Experimental example 3»
Experimental example 2 except that in Example 2, 0.089 g of cesium nitrate was dissolved in 3.23 g of distilled water, an aqueous solution in which 0.18 g of cesium nitrate was dissolved in 3.21 g of distilled water was used. In the same manner as in No. 2, an ammonia decomposition catalyst (hereinafter referred to as “2% Cs—CoMoO 4 ”) was obtained. The state after uniformly infiltrated with cesium nitrate and dried at 90 ° C. for 10 hours was confirmed to be α-CoMoO 4 by X-ray diffraction measurement (see Table 5). In addition, all the peaks shown in Table 5 are peaks derived from CoMoO 4 .
窒化処理後の状態は、Ｘ線回折測定により、金属窒化物が形成されていることを確認した（表６を参照）。なお、表６に示すピークのうち、ピーク番号３はＭｏ由来であると思われるが、それ以外は、すべて、Ｃｏ３Ｍｏ３Ｎ由来のピークである。ただし、Ｃｓを添加したことにより、結晶格子の歪みで、２θの値には、ずれが生じている。 The state after the nitriding treatment confirmed that metal nitride was formed by X-ray diffraction measurement (see Table 6). Of the peaks shown in Table 6, peak number 3 seems to be derived from Mo, but all other peaks are peaks derived from Co 3 Mo 3 N. However, the addition of Cs causes a shift in the value of 2θ due to distortion of the crystal lattice.
≪実験例４≫
実験例２において、硝酸セシウム０．０８９ｇを蒸留水３．２３ｇに溶解させた水溶液に代えて、硝酸セシウム０．４６ｇを蒸留水３．２０ｇに溶解させた水溶液を用いたこと以外は、実験例２と同様にして、アンモニア分解触媒（以下「５％Ｃｓ−ＣｏＭｏＯ４」と表示する）を得た。なお、硝酸セシウムを均一に浸透させ、９０℃で１０時間乾燥させた後の状態は、Ｘ線回折測定により、α−ＣｏＭｏＯ４であることを確認した（表７を参照）。なお、表７に示すピークは、すべて、ＣｏＭｏＯ４由来のピークである。
<< Experimental Example 4 >>
Experimental Example 2 except that in Example 2, 0.089 g of cesium nitrate was dissolved in 3.23 g of distilled water, an aqueous solution in which 0.46 g of cesium nitrate was dissolved in 3.20 g of distilled water was used. In the same manner as in No. 2, an ammonia decomposition catalyst (hereinafter referred to as “5% Cs—CoMoO 4 ”) was obtained. The state after uniformly infiltrating cesium nitrate and drying at 90 ° C. for 10 hours was confirmed to be α-CoMoO 4 by X-ray diffraction measurement (see Table 7). In addition, all the peaks shown in Table 7 are peaks derived from CoMoO 4 .
窒化処理後の状態は、Ｘ線回折測定により、金属窒化物が形成されていることを確認した（表８を参照）。なお、表８に示すピークのうち、ピーク番号４はＭｏ由来であると思われるが、それ以外は、すべて、Ｃｏ３Ｍｏ３Ｎ由来のピークである。ただし、Ｃｓを添加したことにより、結晶格子の歪みで、２θの値には、ずれが生じている。 The state after the nitriding treatment confirmed that metal nitride was formed by X-ray diffraction measurement (see Table 8). Of the peaks shown in Table 8, peak number 4 seems to be derived from Mo, but all other peaks are peaks derived from Co 3 Mo 3 N. However, the addition of Cs causes a shift in the value of 2θ due to distortion of the crystal lattice.
≪実験例５〜７≫
実験例１において、硝酸コバルト六水和物およびモリブデン酸アンモニウムの量を適宜変更したこと以外は、実験例１と同様にして、コバルトとモリブデンとのモル比（Ｃｏ／Ｍｏ）が、実験例５では、１．０５であるアンモニア分解触媒（以下「Ｃｏ／Ｍｏ＝１．０５」と表示する）、実験例６では、１．１０であるアンモニア分解触媒（以下「Ｃｏ／Ｍｏ＝１．１０」と表示する）、実験例７では、０．９０であるアンモニア分解触媒（以下「Ｃｏ／Ｍｏ＝０．９０」と表示する）を得た。なお、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した後の状態は、Ｘ線回折測定により、それぞれ、α−ＣｏＭｏＯ４であることを確認した。なお、実験例５〜７のアンモニア分解触媒については、ピーク強度などのデータを表で示さないが、実験例１〜４のアンモニア分解触媒とほとんど変わらなかった。
<< Experimental Examples 5-7 >>
In Example 1, except that the amounts of cobalt nitrate hexahydrate and ammonium molybdate were appropriately changed, the molar ratio of cobalt to molybdenum (Co / Mo) was changed to Example 5 except that the amounts of cobalt nitrate hexahydrate and ammonium molybdate were changed. Then, an ammonia decomposition catalyst having 1.05 (hereinafter referred to as “Co / Mo = 1.05”), and in Experimental Example 6, an ammonia decomposition catalyst having 1.10 (hereinafter “Co / Mo = 1.10”). In Example 7, an ammonia decomposition catalyst with 0.90 (hereinafter referred to as “Co / Mo = 0.90”) was obtained. Incidentally, under a nitrogen stream, then calcined 5 hours at 350 ° C., under an air stream, the state after firing for 3 hours at 500 ° C., the X-ray diffraction measurement, respectively, it was confirmed that the α-CoMoO 4. In addition, about the ammonia decomposition catalyst of Experimental Examples 5-7, although data, such as a peak intensity, are not shown by a table | surface, it was almost the same as the ammonia decomposition catalyst of Experimental Examples 1-4.
≪実験例８≫
実験例１において、硝酸コバルト六水和物を硝酸ニッケル六水和物に変更したこと以外は、実験例１と同様にして、アンモニア分解触媒（以下「ＮｉＭｏＯ４」と表示する）を得た。なお、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した後の状態は、Ｘ線回折測定により、α−ＣｏＭｏＯ４型を示すＮｉＭｏＯ４であることを確認した。得られたアンモニア分解触媒のＸ線回折パターンを図１に示す。図１から明らかなように、ほぼ全てが窒化物に変化していることがわかる。
<< Experimental Example 8 >>
In Experimental Example 1, an ammonia decomposition catalyst (hereinafter referred to as “NiMoO 4 ”) was obtained in the same manner as Experimental Example 1, except that the cobalt nitrate hexahydrate was changed to nickel nitrate hexahydrate. Incidentally, under a nitrogen stream, then calcined 5 hours at 350 ° C., confirmed that an air stream, the state after firing for 3 hours at 500 ° C., the X-ray diffraction measurement, a NiMoO 4 showing the 4 type alpha-CoMoO did. The X-ray diffraction pattern of the obtained ammonia decomposition catalyst is shown in FIG. As is clear from FIG. 1, it can be seen that almost all of them are changed to nitride.
≪実験例９≫
実験例８において、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した後の状態を、Ｘ線回折測定により、α−ＣｏＭｏＯ４型を示すＮｉＭｏＯ４であることを確認してから、このα−ＣｏＭｏＯ４型を示すＮｉＭｏＯ４に、硝酸セシウム０．０７５ｇを蒸留水１．５５ｇに溶解させた水溶液を、滴下して均一に浸透させ、９０℃で１０時間乾燥させた後、窒化処理を行ったこと以外は、実験例８と同様にして、アンモニア分解触媒（以下「１％Ｃｓ−ＮｉＭｏＯ４」と表示する）を得た。なお、窒化処理前の状態は、Ｘ線回折測定により、α−ＣｏＭｏＯ４型を示すＮｉＭｏＯ４であることを確認した。得られたアンモニア分解触媒の回折パターンを図で示さないが、実験例８のアンモニア分解触媒と同様であった。
≪Experimental example 9≫
In Experimental Example 8, the state after calcination at 350 ° C. for 5 hours in a nitrogen stream and after calcination at 500 ° C. for 3 hours in an air stream is NiMoO 4 showing α-CoMoO 4 type by X-ray diffraction measurement. After confirming this, an aqueous solution in which 0.075 g of cesium nitrate was dissolved in 1.55 g of distilled water was dropped into NiMoO 4 showing the α-CoMoO 4 type, and the solution was uniformly infiltrated and stirred at 90 ° C. for 10 hours. After drying, an ammonia decomposition catalyst (hereinafter referred to as “1% Cs—NiMoO 4 ”) was obtained in the same manner as in Experimental Example 8 except that nitriding treatment was performed. The state before the nitriding treatment was confirmed to be NiMoO 4 showing α-CoMoO 4 type by X-ray diffraction measurement. Although the diffraction pattern of the obtained ammonia decomposition catalyst is not shown in the figure, it was the same as the ammonia decomposition catalyst of Experimental Example 8.
≪実験例１０および１１≫
実験例９において、硝酸セシウム０．０７５ｇを蒸留水１．５５ｇに溶解させた水溶液に代えて、実験例１０では、硝酸セシウム０．１５ｇを蒸留水１．５５ｇに溶解させた水溶液を用いたこと、実験例１１では、硝酸セシウム０．４０ｇを蒸留水１．５５ｇに溶解させた水溶液を用いたこと以外は、実験例９と同様にして、それぞれ、アンモニア分解触媒（以下「２％Ｃｓ−ＮｉＭｏＯ４」と表示する）およびアンモニア分解触媒（以下「５％Ｃｓ−ＮｉＭｏＯ４」と表示する）を得た。なお、窒化処理前の状態は、それぞれ、Ｘ線回折測定により、α−ＣｏＭｏＯ４型を示すＮｉＭｏＯ４であることを確認した。得られたアンモニア分解触媒の回折パターンを図で示さないが、実験例８のアンモニア分解触媒と同様であった。
<< Experimental Examples 10 and 11 >>
In Experimental Example 9, instead of an aqueous solution in which 0.075 g of cesium nitrate was dissolved in 1.55 g of distilled water, an aqueous solution in which 0.15 g of cesium nitrate was dissolved in 1.55 g of distilled water was used in Experimental Example 10. In Experimental Example 11, an ammonia decomposition catalyst (hereinafter referred to as “2% Cs—NiMoO”) was prepared in the same manner as in Experimental Example 9 except that an aqueous solution in which 0.40 g of cesium nitrate was dissolved in 1.55 g of distilled water was used. 4 ”) and an ammonia decomposition catalyst (hereinafter referred to as“ 5% Cs—NiMoO 4 ”). The state before the nitriding treatment was confirmed to be NiMoO 4 indicating α-CoMoO 4 type by X-ray diffraction measurement. Although the diffraction pattern of the obtained ammonia decomposition catalyst is not shown in the figure, it was the same as the ammonia decomposition catalyst of Experimental Example 8.
≪実験例１２≫
ＳＵＳ３１６製の反応管に、市販の酸化モリブデン（ＭｏＯ３）０．５〜１．０ｍＬを充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「ＭｏＯ３」と表示する）を得た。得られたアンモニア分解触媒のＸ線回折パターンを図２に示す。図１から明らかなように、ほぼ全てが元の酸化物のままで、一部のみ窒化物に変化していることがわかる。
«Experimental example 12»
A reaction tube made of SUS316 was charged with 0.5 to 1.0 mL of commercially available molybdenum oxide (MoO 3 ), and heated to 400 ° C. while flowing nitrogen of 30 to 50 mL / min. Next, while flowing ammonia at 50 to 100 mL / min, the temperature is raised to 700 ° C. and a treatment (nitriding treatment) is performed at 700 ° C. for 5 hours to obtain an ammonia decomposition catalyst (hereinafter referred to as “MoO 3 ”). It was. The X-ray diffraction pattern of the obtained ammonia decomposition catalyst is shown in FIG. As is apparent from FIG. 1, it can be seen that almost all of the original oxide remains and only a part of the oxide is changed to nitride.
≪実験例１３≫
硝酸セシウム０．２１ｇを蒸留水１．６２ｇに溶解させた水溶液を、市販の酸化モリブデン（ＭｏＯ３）７．００ｇに滴下して均一に浸透させ、１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。
<< Experimental Example 13 >>
An aqueous solution obtained by dissolving 0.21 g of cesium nitrate in 1.62 g of distilled water is dropped into 7.00 g of commercially available molybdenum oxide (MoO 3 ) and uniformly infiltrated, and dried at 120 ° C. for 10 hours. Then, it was calcined at 350 ° C. for 5 hours, and calcined at 500 ° C. for 3 hours in an air stream.
さらに、ＳＵＳ３１６製の反応管に、焼成物を０．５〜１．０ｍＬ充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「２％Ｃｓ−ＭｏＯ３」と表示する）を得た。得られたアンモニア分解触媒の回折パターンを図で示さないが、実験例１２のアンモニア分解触媒と同様であった。 Furthermore, 0.5 to 1.0 mL of the fired product was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30 to 50 mL / min of nitrogen. Next, while flowing ammonia at 50 to 100 mL / min, the temperature was raised to 700 ° C., and a treatment (nitriding treatment) was performed at 700 ° C. for 5 hours to display an ammonia decomposition catalyst (hereinafter “2% Cs—MoO 3 ”). Obtained). Although the diffraction pattern of the obtained ammonia decomposition catalyst is not shown in the figure, it was the same as the ammonia decomposition catalyst of Experimental Example 12.
≪実験例１４および１５≫
実験例１３において、硝酸セシウム０．２１ｇを蒸留水１．６２ｇに溶解させた水溶液に代えて、実験例１４では、硝酸セシウム０．５４ｇを蒸留水１．６２ｇに溶解させた水溶液を用いたこと、実験例１５では、硝酸セシウム１．１４ｇを蒸留水１．６２ｇに溶解させた水溶液を用いたこと以外は、実験例１３と同様にして、それぞれ、アンモニア分解触媒（以下「５％Ｃｓ−ＭｏＯ３」と表示する）およびアンモニア分解触媒（以下「１０％Ｃｓ−ＭｏＯ３」と表示する）を得た。得られたアンモニア分解触媒の回折パターンを図で示さないが、実験例１２のアンモニア分解触媒と同様であった。
<< Experimental Examples 14 and 15 >>
In Experimental Example 13, instead of an aqueous solution in which 0.21 g of cesium nitrate was dissolved in 1.62 g of distilled water, an aqueous solution in which 0.54 g of cesium nitrate was dissolved in 1.62 g of distilled water was used in Experimental Example 14. In Experimental Example 15, an ammonia decomposition catalyst (hereinafter referred to as “5% Cs—MoO”) was prepared in the same manner as in Experimental Example 13, except that an aqueous solution in which 1.14 g of cesium nitrate was dissolved in 1.62 g of distilled water was used. 3 ”) and an ammonia decomposition catalyst (hereinafter referred to as“ 10% Cs—MoO 3 ”). Although the diffraction pattern of the obtained ammonia decomposition catalyst is not shown in the figure, it was the same as the ammonia decomposition catalyst of Experimental Example 12.
≪実験例１６≫
硝酸コバルト六水和物９．４９ｇを蒸留水４１．１８ｇに溶解させ、メタタングステン酸アンモニウム水溶液（略称「ＭＷ−２」、日本無機化学工業株式会社製；酸化タングステンとして、５０質量％含有）１５．１３ｇを添加した。両方の溶液を混合した後、加熱攪拌し、蒸発乾固させた。得られた固形物を１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。
<< Experimental Example 16 >>
9.49 g of cobalt nitrate hexahydrate was dissolved in 41.18 g of distilled water, and an aqueous ammonium metatungstate solution (abbreviation “MW-2”, manufactured by Nippon Inorganic Chemical Industries, Ltd .; containing 50% by mass as tungsten oxide) 15 .13 g was added. After mixing both solutions, they were heated and stirred and evaporated to dryness. The obtained solid was dried at 120 ° C. for 10 hours, calcined at 350 ° C. for 5 hours under a nitrogen stream, and calcined at 500 ° C. for 3 hours under an air stream.
さらに、ＳＵＳ３１６製の反応管に、焼成物を０．５〜１．０ｍＬ充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「ＣｏＷＯ４」と表示する）を得た。得られたアンモニア分解触媒のＸ線回折パターンを図３に示す。図３から明らかなように、酸化物が部分窒化されたもの（ＣｏＷＯ１．２Ｎ）と、酸化物が還元により金属化されたもの（Ｃｏ３Ｗ）とに変化していることがわかる。 Furthermore, 0.5 to 1.0 mL of the fired product was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30 to 50 mL / min of nitrogen. Next, while flowing ammonia at 50 to 100 mL / min, the temperature is raised to 700 ° C., and a treatment (nitriding treatment) is performed at 700 ° C. for 5 hours to obtain an ammonia decomposition catalyst (hereinafter referred to as “CoWO 4 ”). It was. The X-ray diffraction pattern of the obtained ammonia decomposition catalyst is shown in FIG. As is apparent from FIG. 3, it can be seen that the oxide is changed to a partially nitrided (CoWO 1.2 N) and the oxide is metalized by reduction (Co 3 W).
≪実験例１７≫
硝酸マンガン六水和物１３．３６ｇを蒸留水６７．０８ｇに溶解させた。別途、沸騰させた蒸留水４１．０４ｇにモリブデン酸アンモニウム８．２２ｇを徐々に添加して溶解させた。両方の水溶液を混合した後、加熱攪拌し、蒸発乾固させた。得られた固形物を１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。Ｘ線回折測定により、α−ＭｎＭｏＯ４であることを確認した。
<< Experimental Example 17 >>
Manganese nitrate hexahydrate (13.36 g) was dissolved in distilled water (67.08 g). Separately, 8.22 g of ammonium molybdate was gradually added and dissolved in 41.04 g of boiling distilled water. After mixing both aqueous solutions, it was heated and stirred and evaporated to dryness. The obtained solid was dried at 120 ° C. for 10 hours, calcined at 350 ° C. for 5 hours under a nitrogen stream, and calcined at 500 ° C. for 3 hours under an air stream. It was confirmed to be α-MnMoO 4 by X-ray diffraction measurement.
さらに、ＳＵＳ３１６製の反応管に、焼成物を０．５〜１．０ｍＬ充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「ＭｎＭｏＯ４」と表示する）を得た。 Furthermore, 0.5 to 1.0 mL of the fired product was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30 to 50 mL / min of nitrogen. Next, while flowing ammonia at 50 to 100 mL / min, the temperature is raised to 700 ° C. and a treatment (nitriding treatment) is performed at 700 ° C. for 5 hours to obtain an ammonia decomposition catalyst (hereinafter referred to as “MnMoO 4 ”). It was.
≪実験例１８≫
硝酸カルシウム四水和物１１．８１ｇを蒸留水６０．１０ｇに溶解させた。別途、沸騰させた蒸留水４５．０６ｇにモリブデン酸アンモニウム８．８３ｇを徐々に添加して溶解させた。両方の水溶液を混合した後、加熱攪拌し、蒸発乾固させた。得られた固形物を１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。
<< Experimental Example 18 >>
11.81 g of calcium nitrate tetrahydrate was dissolved in 60.10 g of distilled water. Separately, 8.83 g of ammonium molybdate was gradually added and dissolved in 45.06 g of boiling distilled water. After mixing both aqueous solutions, it was heated and stirred and evaporated to dryness. The obtained solid was dried at 120 ° C. for 10 hours, calcined at 350 ° C. for 5 hours under a nitrogen stream, and calcined at 500 ° C. for 3 hours under an air stream.
さらに、ＳＵＳ３１６製の反応管に、焼成物を０．５〜１．０ｍＬ充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「ＣａＭｏＯ４」と表示する）を得た。 Furthermore, 0.5 to 1.0 mL of the fired product was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30 to 50 mL / min of nitrogen. Next, while flowing ammonia at 50 to 100 mL / min, the temperature is raised to 700 ° C. and a treatment (nitriding treatment) is performed at 700 ° C. for 5 hours to obtain an ammonia decomposition catalyst (hereinafter referred to as “CaMoO 4 ”). It was.
≪実験例１９≫
硝酸マグネシウム六水和物１３．９２ｇを蒸留水７０．０２ｇに溶解させた。別途、沸騰させた蒸留水４８．０３ｇにモリブデン酸アンモニウム９．５８ｇを徐々に添加して溶解させた。両方の水溶液を混合した後、加熱攪拌し、蒸発乾固させた。得られた固形物を１２０℃で１０時間乾燥させた後、窒素気流下、３５０℃で５時間焼成し、空気気流下、５００℃で３時間焼成した。
<< Experimental Example 19 >>
13.92 g of magnesium nitrate hexahydrate was dissolved in 70.02 g of distilled water. Separately, 9.58 g of ammonium molybdate was gradually added and dissolved in 48.03 g of boiling distilled water. After mixing both aqueous solutions, it was heated and stirred and evaporated to dryness. The obtained solid was dried at 120 ° C. for 10 hours, calcined at 350 ° C. for 5 hours under a nitrogen stream, and calcined at 500 ° C. for 3 hours under an air stream.
さらに、ＳＵＳ３１６製の反応管に、焼成物を０．５〜１．０ｍＬ充填し、窒素３０〜５０ｍＬ／ｍｉｎを流しながら、４００℃まで昇温した。次いで、アンモニア５０〜１００ｍＬ／ｍｉｎを流しながら、７００℃まで昇温し、７００℃で５時間保持する処理（窒化処理）を行って、アンモニア分解触媒（以下「ＭｇＭｏＯ４」と表示する）を得た。 Furthermore, 0.5 to 1.0 mL of the fired product was charged into a reaction tube made of SUS316, and the temperature was raised to 400 ° C. while flowing 30 to 50 mL / min of nitrogen. Next, while flowing ammonia at 50 to 100 mL / min, the temperature is raised to 700 ° C. and a treatment (nitriding treatment) is performed at 700 ° C. for 5 hours to obtain an ammonia decomposition catalyst (hereinafter referred to as “MgMoO 4 ”). It was.
≪アンモニア分解反応≫
実験例１〜１９で得られた各触媒、および、純度９９．９体積％以上のアンモニアを用いて、アンモニア分解反応を行い、アンモニアを窒素と水素とに分解した。
≪Ammonia decomposition reaction≫
Using each catalyst obtained in Experimental Examples 1 to 19 and ammonia having a purity of 99.9% by volume or more, an ammonia decomposition reaction was performed to decompose the ammonia into nitrogen and hydrogen.
なお、アンモニア分解率は、アンモニアの空間速度６，０００ｈ−１、反応温度４００℃、４５０℃、または、５００℃、反応圧力０．１０１３２５ＭＰａ（常圧）の条件下で測定した（下記式により算出した）。その結果を表９に示す。 The ammonia decomposition rate was measured under the conditions of an ammonia space velocity of 6,000 h −1 , a reaction temperature of 400 ° C., 450 ° C., or 500 ° C., and a reaction pressure of 0.101325 MPa (normal pressure) (calculated by the following formula). did). The results are shown in Table 9.
表９から明らかなように、実験例１〜１９のアンモニア分解触媒は、いずれも、純度９９．９体積％以上という高濃度のアンモニアを、４００〜５００℃という比較的低温で、かつ、６，０００ｈ−１という高い空間速度で効率よく窒素と水素とに分解することができる。また、実験例１〜１１のアンモニア触媒は、Ａ成分であるモリブデンとＢ成分であるコバルトまたはニッケルとの複合酸化物であるので、アンモニア分解率が比較的高い。さらに、実験例２〜４のアンモニア分解触媒は、特にＡ成分であるモリブデンとＢ成分であるコバルトとの複合酸化物にＣ成分であるセシウムが添加されているので、アンモニア分解率が非常に高い。 As can be seen from Table 9, the ammonia decomposition catalysts of Experimental Examples 1 to 19 are each made of a high concentration of ammonia having a purity of 99.9% by volume or more at a relatively low temperature of 400 to 500 ° C. and 6, It can be efficiently decomposed into nitrogen and hydrogen at a high space velocity of 000 h −1 . Moreover, since the ammonia catalysts of Experimental Examples 1 to 11 are complex oxides of molybdenum as the A component and cobalt or nickel as the B component, the ammonia decomposition rate is relatively high. Furthermore, the ammonia decomposition catalysts of Experimental Examples 2 to 4 have a very high ammonia decomposition rate because cesium as the C component is added to the composite oxide of molybdenum as the A component and cobalt as the B component. .
本発明は、アンモニアの分解に関するものであり、アンモニアを含有するガスを処理して無臭化する環境分野や、アンモニアを窒素と水素とに分解して水素を取得するエネルギー分野などにおいて、多大の貢献をなすものである。 The present invention relates to the decomposition of ammonia, and makes a great contribution in the environmental field in which ammonia-containing gas is treated and non-brominated, and in the energy field in which ammonia is decomposed into nitrogen and hydrogen to obtain hydrogen. It is what makes.
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