JPWO2005018807A1 - Ammonia decomposition catalyst and ammonia decomposition method using the catalyst - Google Patents
Ammonia decomposition catalyst and ammonia decomposition method using the catalyst Download PDFInfo
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- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8634—Ammonia
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- B01J29/00—Catalysts comprising molecular sieves
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- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
- B01J29/10—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y containing iron group metals, noble metals or copper
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- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
- B01J29/20—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type containing iron group metals, noble metals or copper
- B01J29/24—Iron group metals or copper
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- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J29/405—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead
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- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J29/42—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing iron group metals, noble metals or copper
- B01J29/46—Iron group metals or copper
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- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
- B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
- B01J29/76—Iron group metals or copper
- B01J29/7615—Zeolite Beta
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- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/30—Ion-exchange
Abstract
本発明は、排ガス中の高濃度アンモニアを接触分解する際に、還元剤の存在がなくとも高い分解能力を示し、かつ、一酸化炭素、二酸化炭素、一酸化窒素などの窒素酸化物を生成しない触媒及び該触媒を用いたアンモニアの分解方法を示すものである。本発明のアンモニア分解触媒は、Ｓｉ／Ａｌ（原子比）が１〜９０であり、比表面積が２００〜９００ｍ２／ｇである多孔質シリカアルミナに、周期表の第８族〜第１２族の金属元素から選ばれる少なくとも一つの金属元素を、イオン交換法により担持させたものである。The present invention shows high decomposition ability even in the absence of a reducing agent when catalytically decomposing high-concentration ammonia in exhaust gas, and does not produce nitrogen oxides such as carbon monoxide, carbon dioxide, and nitrogen monoxide. 1 shows a catalyst and a method for decomposing ammonia using the catalyst. The ammonia decomposition catalyst of the present invention is made of porous silica alumina having Si / Al (atomic ratio) of 1 to 90 and specific surface area of 200 to 900 m2 / g, and metals of Groups 8 to 12 of the periodic table. At least one metal element selected from the elements is supported by an ion exchange method.
Description
本発明は、アンモニア含有排ガスの除害に有用なアンモニア分解触媒、特に、半導体製造装置やＬＣＤ製造装置等から、排出される排ガスに含有される高濃度のアンモニアを分解するアンモニア分解用触媒に関し、さらに該触媒を用いたアンモニアの分解方法に関する。 The present invention relates to an ammonia decomposition catalyst useful for detoxification of ammonia-containing exhaust gas, particularly an ammonia decomposition catalyst that decomposes high-concentration ammonia contained in exhaust gas discharged from a semiconductor manufacturing apparatus, an LCD manufacturing apparatus, or the like. Further, the present invention relates to a method for decomposing ammonia using the catalyst.
半導体製造工場、青色ダイオード製造工場などでは、それらの製造中にアンモニアが使用されている。これらのガスは可燃性かつ有害性であることから、これらを含有する排ガスを、環境保護の観点から、大気中にそのまま放出することはできず、その危険性や有害性をなくするために除害処理が必要である。
排ガス処理には、湿式法、燃焼法あるいは乾式法がある。例えば、湿式法は薬液で排ガスを洗浄処理する方法であり、燃焼法は、バーナーなどにより、高温で燃焼し、無害なガスに処理する方法である。また、乾式法は、固体処理剤もしくは分解触媒の充填塔に排ガスを流通させ、除害対象ガスと処理剤との化学的作用、即ち、吸着及び／又は化学反応により、吸収する、もしくは触媒の働きにより、無害物質に分解する方法であり、金属水素化物含有排ガス、ハロゲン化物ガスあるいはアンモニア含有排ガスの処理で多く行われている。
しかしながら、湿式法の場合、排水中にアンモニアが排出されることとなり、この廃水を処理することが必要となる。また、燃焼法の場合では、アンモニアを燃焼する際に生じるＮＯｘの処理が問題となる。
一方、乾式法でアンモニアを除害するのに用いるアンモニア分解触媒は数多くの技術が知られている。
例えば、アンモニア分解触媒として、酸化銅、酸化クロム、酸化マンガン、酸化鉄、パラジウム、白金などを使用するもの（特開平１１−４２４２２号公報）、ゼオライトにクロム、銅もしくはコバルトを担持したもの（特開平０７−３２８４４０号公報）、あるいは周期表（亜族方式）の第８族の金属元素又は及び第１Ｂ族の金属元素を含むもの（特開平１０−２４９１６５号公報）が挙げられる。
しかしながら、酸化銅、酸化クロム、酸化マンガン、酸化鉄、パラジウムあるいは白金からなる分解触媒は、アンモニア分解に優れた能力を有するが、副反応として一酸化二窒素、二酸化窒素、一酸化窒素などの窒素酸化物を生成するために環境上、問題がある。
また、ゼオライトにクロム、銅もしくはコバルトを担持した分解触媒は、窒素酸化物の生成を可及的に抑えながら、アンモニアを分解することを目的としたものであるが、実際にテストした被処理ガスはアンモニアの濃度が３０ｐｐｍと非常に低濃度であり、酸素濃度も２％と非常に低濃度である。すなわち、かなり制限された条件で有効であることが示されているに過ぎない。半導体製造などで排出されるアンモニア濃度は、数容量％と非常に高く、かつ、酸素濃度も空気に近い濃度を有するために、上記の触媒では、一酸化二窒素、二酸化窒素、一酸化窒素などの窒素酸化物の生成は避けることができない。
周期表（亜族方式）の第８族の金属元素又は／及び第１Ｂ族の金属元素を含む触媒は、還元剤として水素を共存させることにより低温でアンモニアを分解でき、窒素酸化物を生じることがないが、水素の共存が必須であり、コスト面で不利である。In semiconductor manufacturing plants, blue diode manufacturing plants, etc., ammonia is used during their manufacturing. Since these gases are flammable and harmful, the exhaust gas containing them cannot be released into the atmosphere as it is from the viewpoint of environmental protection, and must be removed to eliminate the danger and harm. Harmful treatment is necessary.
As the exhaust gas treatment, there are a wet method, a combustion method, and a dry method. For example, the wet method is a method of cleaning exhaust gas with a chemical solution, and the combustion method is a method of combusting at a high temperature with a burner or the like and processing it into a harmless gas. In the dry method, exhaust gas is circulated through a packed column of a solid treatment agent or a cracking catalyst and absorbed by the chemical action of the gas to be removed and the treatment agent, that is, adsorption and / or chemical reaction, or the catalyst. It is a method of decomposing into harmless substances by working, and is often performed in the treatment of exhaust gas containing metal hydride, halide gas or ammonia containing exhaust gas.
However, in the case of the wet method, ammonia is discharged into the waste water, and it is necessary to treat this waste water. In the case of the combustion method, the treatment of NO x generated when ammonia is burned becomes a problem.
On the other hand, many techniques are known for the ammonia decomposition catalyst used for removing ammonia by a dry method.
For example, a catalyst that uses copper oxide, chromium oxide, manganese oxide, iron oxide, palladium, platinum or the like as an ammonia decomposition catalyst (Japanese Patent Laid-Open No. 11-42422), a zeolite carrying chromium, copper, or cobalt (special (Kaihei 07-328440), or those containing a group 8 metal element or a group 1B metal element of the periodic table (subgroup system) (Japanese Patent Laid-Open No. 10-249165).
However, the decomposition catalyst made of copper oxide, chromium oxide, manganese oxide, iron oxide, palladium or platinum has an excellent ability to decompose ammonia, but as a side reaction, nitrogen such as dinitrogen monoxide, nitrogen dioxide, and nitric oxide. There are environmental problems due to the generation of oxides.
The cracking catalyst with chromium, copper, or cobalt supported on zeolite is intended to decompose ammonia while suppressing the generation of nitrogen oxide as much as possible. Has a very low ammonia concentration of 30 ppm and an oxygen concentration of 2%. That is, it has only been shown to be effective in very limited conditions. The ammonia concentration discharged in semiconductor manufacturing etc. is as high as several volume% and the oxygen concentration is close to air, so in the above catalyst, dinitrogen monoxide, nitrogen dioxide, nitrogen monoxide, etc. The formation of nitrogen oxides cannot be avoided.
A catalyst containing a Group 8 metal element or / and a Group 1B metal element of the periodic table (subgroup method) can decompose ammonia at a low temperature by coexisting hydrogen as a reducing agent to generate nitrogen oxides. However, coexistence of hydrogen is essential, which is disadvantageous in terms of cost.
したがって、本発明の課題は、半導体製造工程等で発生する高濃度のアンモニアを含む排ガスの処理において、還元剤の存在がなくとも、高い分解能力を示し、かつ、一酸化二窒素、二酸化窒素、一酸化窒素などの窒素酸化物を生成しない触媒を提供すること、また、高濃度のアンモニアを含む排ガスを効率よく除害する方法を提供することである。
本発明者らは、上記課題を解決するため種々の研究開発を行った結果、特定性状の多孔質シリカアルミナを担体とし、これに周期表の第８族〜第１２族の金属元素から選ばれる少なくとも１つの金属元素をイオン交換法により、細孔内に担持させた触媒は、一酸化二窒素、二酸化窒素、一酸化窒素などの窒素酸化物の発生を抑制しながら、パーセントオーダーの高濃度アンモニアを効率的に分解できることを見出し、本発明を完成するに至った。
すなわち、本発明は、０．００５〜５容量％のアンモニアを含むがガスを触媒に接触させて、アンモニアを接触分解する触媒であって、該触媒が多孔質シリカアルミナを担体とし、これに周期表の第８族〜第１２族の金属元素から選ばれる少なくとも一つの金属元素をイオン交換法により担持したものであり、該多孔質シリカアルミナのＳｉ／Ａｌ（原子比）が１〜９０であり、その比表面積が２００〜９００ｍ２／ｇであることを特徴とするアンモニア分解触媒である。
なお、上記触媒における周期表第８族〜第１２族の金属元素含有量が全触媒質量に対し０．０５〜１０質量％であること、また、多孔質シリカアルミナは平均粒子径が０．１〜２０μｍであるものが好ましい。
また、本発明は、０．００５〜５容量％のアンモニアを含むガスを触媒に接触させて、アンモニアを接触分解するに際し、上記触媒を使用することを特徴とするアンモニア分解方法である。Therefore, the problem of the present invention is that in the treatment of exhaust gas containing high-concentration ammonia generated in the semiconductor manufacturing process or the like, even if there is no reducing agent, it exhibits high decomposition ability, and dinitrogen monoxide, nitrogen dioxide, It is to provide a catalyst that does not produce nitrogen oxides such as nitrogen monoxide, and to provide a method for efficiently removing exhaust gas containing high concentration of ammonia.
As a result of various research and development to solve the above-mentioned problems, the inventors of the present invention use porous silica alumina having specific properties as a support, and are selected from Group 8 to Group 12 metal elements of the periodic table. A catalyst in which at least one metal element is supported in the pores by an ion exchange method suppresses the generation of nitrogen oxides such as dinitrogen monoxide, nitrogen dioxide, and nitrogen monoxide, and is highly concentrated ammonia on the order of percent. Has been found to be efficiently decomposed, and the present invention has been completed.
That is, the present invention is a catalyst that contains 0.005 to 5% by volume of ammonia but contacts gas with a catalyst to catalytically decompose ammonia, and the catalyst uses porous silica alumina as a carrier, and this is a periodic cycle. At least one metal element selected from Group 8 to Group 12 metal elements in the table is supported by an ion exchange method, and Si / Al (atomic ratio) of the porous silica alumina is 1 to 90 The ammonia decomposition catalyst is characterized by having a specific surface area of 200 to 900 m 2 / g.
In addition, the metal element content of Group 8 to Group 12 of the periodic table in the catalyst is 0.05 to 10% by mass with respect to the total catalyst mass, and the average particle size of porous silica alumina is 0.1. What is -20 micrometers is preferable.
In addition, the present invention is an ammonia decomposing method characterized in that the catalyst is used when catalytically decomposing ammonia by bringing a gas containing 0.005 to 5% by volume of ammonia into contact with the catalyst.
本発明を適用することができるアンモニア含有ガスは特に制限はなく、例えば、半導体工場などの排気ガス、アンモニア含有排水のストリッピングにより発生するアンモニア含有ガスなどを挙げることができる。
本発明を適用できるアンモニア含有ガスのアンモニア濃度は、通常は５０ｐｐｍから５容量％であり、好適には０．１〜４容量％である。
本発明の触媒にアンモニア含有ガスと空気を接触させて、アンモニアを無害な窒素ガスと水に変換し、酸化分解する。反応は次式（Ｉ）のごとく進行する。
４ＮＨ３＋３Ｏ２→２Ｎ２＋６Ｈ２Ｏ （Ｉ）
この酸化分解での温度は、アンモニアの濃度、触媒の性能、触媒との接触時間等により適宜決定されるが、好ましくは２００〜６００℃であり、さらに好ましくは３００〜５００℃である。
本発明で使用する多孔質シリカアルミナは、Ｓｉ／Ａｌ（原子比）が１〜９０であり、比表面積が２００〜９００ｍ２／ｇであればいずれでもよく、天然ゼオライト、合成ゼオライト、メタポーラスゼオライトから適宜選択される。なお、ゼオライトとしては、具体的には、モルデナイト、エリオナイト、クリプチノライト、ＺＳＭ−５、Ｙ型ゼオライト、βゼオライト、ＭＣＭ−４１などが挙げられる。
多孔質シリカアルミナのＳｉ／Ａｌ（原子比）は、１〜９０であり、好ましくは、２〜６０である。Ｓｉ／Ａｌ（原子比）が９０以上になると、イオン交換サイトの減少により、活性成分である金属元素の担持量が少なくなるので好ましくない。
また、多孔質シリカアルミナの比表面積は、２００〜９００ｍ２／ｇであり、好ましくは３００〜７００ｍ２／ｇである。２００ｍ２／ｇ未満の場合、性能が十分発揮されない。
多孔質シリカアルミナの平均粒子径は、好ましくは、０．１〜２０μｍである。多孔質シリカアルミナの平均粒子径が２０μｍ以上の場合、触媒とアンモニアが接触不足になりやすく、十分な性能を発揮しない恐れがある。
多孔質シリカアルミナは、ナトリウム交換タイプとして合成されることが多く、それを使用することができる。また、ナトリウム交換タイプから、イオン交換操作により、プロトンタイプとすることもできる。
また、多孔質シリカアルミナは市販品として入手可能であり、粉状物、それをペレット化したもの、さらにペレット化したものを粉砕して顆粒としたもので用いられる。なお、該多孔質シリカアルミナはその平均粒子径が０．１〜２０μｍのものを用いるのであるが、取り扱いの容易さからペレット状、あるいは顆粒状としたものが望ましい。
多孔質シリカアルミナに担持させる金属元素は、周期表の第８族〜第１２族に属する金属元素であり、Ｆｅ、Ｒｕ、Ｃｏ、Ｒｈ、Ｎｉ、Ｐｄ、Ｐｔ、Ｃｕ、Ａｇ、Ａｕ、Ｚｎ、Ｃｄなどを挙げることができる。これらは単独であっても複数を用いても良い。
これら金属元素は、イオン交換法により上記多孔質シリカアルミナに担持させることが好ましい。通常の含浸法、デップ法、スプレー法の場合、多孔質シリカアルミナの細孔内に金属元素が十分に担持されずに、担体の外表面のみに担持される恐れがある。外表面に担持されると、金属元素同士が凝集することにより、十分な性能が発揮できない。
周期表の第８族〜第１２族の金属元素は、硝酸塩、硫酸塩、酢酸塩、塩化物、アンモニウム錯塩などとして担持させる。
第８族〜第１２族金属元素成分の触媒中の含有量は、触媒全重量に対して０．０５〜１０質量％とするのが望ましく、好ましくは０．１〜５質量％である。なお、この金属元素成分の含有量が、０．０５質量％未満ではアンモニア分解が不充分となりやすく、また、１０質量％を超えると一層の処理性能向上効果が認められなくなるばかりでなく、多孔質シリカアルミナ細孔を塞いでしまい、十分な効果が得られなくなる。
通常のイオン交換法により、周期表の第８族〜第１２族の金属元素を多孔質シリカアルミナに担持させることができる。
粉末状の多孔質シリカアルミナに金族元素成分をイオン交換法により担持して得られた粉末状の触媒は、混練した後、押出し或いは打錠によって成型物とされる。ここで、機械的強度を確保するために、必要に応じて、シリカ、アルミナ、マグネシア、その他の強度改善に有効な無機バインダー類を加えられる。アンモニアを含むガスを分解処理する際に、充填塔に詰められたアンモニア分解触媒層に処理対象ガスを流通するため、触媒層での圧力損失を低減するために成型物とすることは必須であり、必要に応じてこれら成型物は破砕処理して、顆粒状となして使用してもよい。また、高ＳＶで使用する場合は、ハニカムなどの基材に粉末状の触媒をウォッシュコーティングすることにより、添着して使用してもよい。予め多孔質シリカアルミナは押出し、或いは打錠成型され、必要に応じて破砕、顆粒化された固形物にイオン交換法により第８族〜第１２族金属元素成分を担持することもできる。
本発明のアンモニア分解触媒を用いて、アンモニアを含むガスを接触させることによりアンモニア分解する方法について説明する。
アンモニア分解触媒を、ステンレス製流通式反応装置に充填し、アンモニアを含有するガスを反応器に流通させ、触媒層を２００〜６００℃に昇温し、アンモニアを分解する。なお、ガスの流通量としては、触媒、触媒の形状、触媒層の温度により適宜最適条件を設定するが、通常ＳＶ １００〜８０００ｈｒ−１程度、好ましくはＳＶ ２００〜７０００ｈｒ−１、さらに好ましくはＳＶ ４００〜６０００ｈｒ−１とする。また、触媒層の温度を、あまり高くすると窒素酸化物が増え、あまり低くするとアンモニアの分解が十分でなくなる。
最適の触媒層の温度は反応装置よりの出口ガスをガスクロマトグラフ等によってこれらガスの状況を分析して確認することが好ましい。
さらに、アンモニア含有ガス中の酸素量としては、アンモニア１モルに対し０．７５モル以上であることが望ましく、通常２モル以上であれば好ましい。なお、処理ガス中の酸素量が不足する場合は、空気、酸素等をアンモニア含有ガスとともに、あるいはアンモニア含有ガスに添加して、反応装置に流通させる。その際の合計のガス流通量は上記に示す範囲とすることが好ましい。The ammonia-containing gas to which the present invention can be applied is not particularly limited, and examples thereof include exhaust gas from a semiconductor factory, ammonia-containing gas generated by stripping ammonia-containing wastewater, and the like.
The ammonia concentration of the ammonia-containing gas to which the present invention is applicable is usually from 50 ppm to 5% by volume, and preferably from 0.1 to 4% by volume.
An ammonia-containing gas and air are brought into contact with the catalyst of the present invention to convert ammonia into harmless nitrogen gas and water for oxidative decomposition. The reaction proceeds as shown in the following formula (I).
4NH 3 + 3O 2 → 2N 2 + 6H 2 O (I)
The temperature in this oxidative decomposition is appropriately determined depending on the concentration of ammonia, the performance of the catalyst, the contact time with the catalyst, etc., but is preferably 200 to 600 ° C, more preferably 300 to 500 ° C.
The porous silica alumina used in the present invention may be any one as long as Si / Al (atomic ratio) is 1 to 90 and the specific surface area is 200 to 900 m 2 / g. Natural zeolite, synthetic zeolite, metaporous zeolite Is appropriately selected. Specific examples of zeolite include mordenite, erionite, cryptinolite, ZSM-5, Y-type zeolite, β zeolite, and MCM-41.
The Si / Al (atomic ratio) of the porous silica alumina is 1 to 90, preferably 2 to 60. A Si / Al (atomic ratio) of 90 or more is not preferable because the amount of the metal element as an active component is reduced due to a decrease in ion exchange sites.
The specific surface area of the porous silica alumina is 200 to 900 m 2 / g, preferably 300 to 700 m 2 / g. When it is less than 200 m 2 / g, the performance is not sufficiently exhibited.
The average particle diameter of the porous silica alumina is preferably 0.1 to 20 μm. When the average particle diameter of the porous silica alumina is 20 μm or more, the catalyst and ammonia are likely to be insufficiently contacted, and there is a possibility that sufficient performance may not be exhibited.
Porous silica alumina is often synthesized as a sodium exchange type and can be used. Moreover, it can also be changed from a sodium exchange type to a proton type by ion exchange operation.
Porous silica alumina is available as a commercial product, and is used in the form of a powder, a pelletized product thereof, and a pelletized product obtained by pulverizing it. The porous silica alumina having an average particle size of 0.1 to 20 μm is used, but it is preferably in the form of pellets or granules for ease of handling.
The metal element to be supported on the porous silica alumina is a metal element belonging to Group 8 to Group 12 of the periodic table, Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd etc. can be mentioned. These may be used alone or in combination.
These metal elements are preferably supported on the porous silica alumina by an ion exchange method. In the case of a normal impregnation method, a dipping method, and a spray method, there is a possibility that the metal element is not sufficiently supported in the pores of the porous silica alumina and is supported only on the outer surface of the carrier. When supported on the outer surface, sufficient performance cannot be exhibited due to aggregation of metal elements.
The metal elements of Group 8 to Group 12 of the periodic table are supported as nitrates, sulfates, acetates, chlorides, ammonium complex salts, and the like.
The content of the Group 8 to Group 12 metal element component in the catalyst is desirably 0.05 to 10% by mass, preferably 0.1 to 5% by mass with respect to the total weight of the catalyst. In addition, if the content of the metal element component is less than 0.05% by mass, ammonia decomposition tends to be insufficient, and if it exceeds 10% by mass, not only a further improvement in treatment performance is observed, but also the porosity The silica alumina pores are blocked, and a sufficient effect cannot be obtained.
The metal elements of Groups 8 to 12 of the periodic table can be supported on porous silica alumina by a normal ion exchange method.
A powdered catalyst obtained by supporting a metal element component on powdered porous silica alumina by an ion exchange method is kneaded and then formed into a molded product by extrusion or tableting. Here, in order to ensure mechanical strength, silica, alumina, magnesia, and other inorganic binders effective for improving the strength can be added as necessary. When the gas containing ammonia is decomposed, the gas to be processed is circulated through the ammonia decomposition catalyst layer packed in the packed tower. Therefore, it is indispensable to form a molded product in order to reduce the pressure loss in the catalyst layer. If necessary, these molded products may be crushed to form granules. Moreover, when using it by high SV, you may use by adhering by carrying out the wash coating of the powdered catalyst to base materials, such as a honeycomb. Porous silica alumina is extruded or tableted in advance, and the group 8 to 12 metal element components can be supported on the solid material crushed and granulated as necessary by ion exchange.
A method for decomposing ammonia by contacting a gas containing ammonia using the ammonia decomposition catalyst of the present invention will be described.
The ammonia decomposition catalyst is filled in a stainless steel flow reactor, a gas containing ammonia is passed through the reactor, the temperature of the catalyst layer is raised to 200 to 600 ° C., and ammonia is decomposed. The gas flow rate is appropriately set according to the catalyst, the shape of the catalyst, and the temperature of the catalyst layer, but is usually about SV 100 to 8000 hr −1 , preferably SV 200 to 7000 hr −1 , more preferably SV. Set to 400 to 6000 hr −1 . Further, if the temperature of the catalyst layer is too high, nitrogen oxides increase, and if it is too low, the decomposition of ammonia becomes insufficient.
The optimum temperature of the catalyst layer is preferably confirmed by analyzing the state of these gases at the outlet gas from the reactor by gas chromatography or the like.
Furthermore, the amount of oxygen in the ammonia-containing gas is desirably 0.75 mol or more with respect to 1 mol of ammonia, and usually 2 mol or more is preferable. When the amount of oxygen in the processing gas is insufficient, air, oxygen or the like is added to the ammonia-containing gas or to the ammonia-containing gas, and then circulated through the reaction apparatus. In this case, the total gas flow rate is preferably in the range shown above.
以下、実施例により本発明を説明する。
（アンモニア分解触媒の性能評価）
空気中に含まれるアンモニアを分解する性能を測定することによって行った。
測定は常圧流通式反応装置によって行い、その測定装置、測定条件、測定操作法は次の通りである。
常圧流通式反応装置
石英製反応管：内径 ２５ｍｍ、長さ ５００ｍｍ
測定条件
触媒使用量 ：２０ｃｃ（充填高さ４０ｍｍ）
ガスＳＶ ：６２５〜５０００ｈｒ−１
反応圧力 ：１００ｋＰａ（約１大気圧）
反応温度 ：２００〜６００℃
反応ガス組成：アンモニア １容量％（空気中）
入口及び出口ガスの分析
・ＮＨ３、Ｎ２Ｏ
装置 ：日立製作所製、１６４形ガスクロマトグラフィ（商品名）
カラム ：Ｐｏｒａｐａｋ−Ｑ、径 ３ｍｍ、長さ ３ｍ
検出器 ：熱伝対式検出器
ガス ：窒素ガス 流量 ３０ｍｌ／ｍｉｎ
サンプル ：１．０ｍｌ
・ＮＯ、ＮＯ２
装置 ：堀場製作所製、ＣＬＡ−５１０ＳＳ（商品名）
（多孔質シリカアルミナの評価）
・Ｓｉ／Ａｌ（原子比）の測定
ＩＣＰ（島津製作所製、ＩＣＰＳ−１０００（商品名））により分析した。
・比表面積の測定
Ｎ２吸着によるＢＥＴ表面積測定によった。
・平均粒子径
イオン交換水に多孔質シリカアルミナを分散させて、レーザー透過法により測定。なお、成形したものはメノウ乳鉢で微粉化して、２００メッシュの篩を通過したものを測定した。
（アンモニア分解触媒中の金属の分析）
ＩＣＰ（島津製作所製、ＩＣＰＳ−１０００（商品名））により分析した。Hereinafter, the present invention will be described by way of examples.
(Performance evaluation of ammonia decomposition catalyst)
This was done by measuring the ability to decompose ammonia contained in the air.
The measurement is performed by a normal pressure flow type reaction apparatus, and the measurement apparatus, measurement conditions, and measurement operation method are as follows.
Normal pressure flow reactor Reactor made of quartz: inner diameter 25mm, length 500mm
Measurement conditions Catalyst usage: 20cc (filling height 40mm)
Gas SV: 625 to 5000 hr −1
Reaction pressure: 100 kPa (about 1 atmospheric pressure)
Reaction temperature: 200-600 ° C
Reaction gas composition: Ammonia 1% by volume (in air)
Analysis of inlet and outlet gas ・ NH 3 , N 2 O
Apparatus: 164 type gas chromatography (trade name) manufactured by Hitachi, Ltd.
Column: Porapak-Q, diameter 3 mm, length 3 m
Detector: Thermocouple type detector Gas: Nitrogen gas Flow rate 30ml / min
Sample: 1.0ml
・ NO, NO 2
Device: HORIBA, CLA-510SS (trade name)
(Evaluation of porous silica alumina)
-Measurement of Si / Al (atomic ratio) It analyzed by ICP (The Shimadzu Corporation make, ICPS-1000 (brand name)).
· Ratio was by BET surface area measurement by the measuring N 2 adsorption surface area.
-Average particle diameter Porous silica alumina is dispersed in ion-exchanged water and measured by a laser transmission method. In addition, what was shape | molded was pulverized with the agate mortar, and what passed the 200 mesh sieve was measured.
(Analysis of metals in ammonia decomposition catalyst)
Analysis was performed by ICP (manufactured by Shimadzu Corporation, ICPS-1000 (trade name)).
Ｃｕ（ＮＯ３）２・３Ｈ２Ｏ（和光純薬製、試薬特級）８０ｇをイオン交換水に溶解し、１リットルとする。この硝酸銅溶液に、多孔質シリカアルミナ“ＺＳＭ−５ゼオライド”（Ｓｉ／Ａｌ（モル比）＝３０、比表面積５８０ｍ２／ｇ、平均粒子径１０μｍ、ズードケミーＡＧ製、商品名：Ｈ−ＭＦＩ−３０）５００ｇを分散させ、２４時間室温で撹拌して、イオン交換させた。得られたＣｕをイオン交換で吸蔵した多孔質シリカアルミナを濾取し、イオン交換水で洗浄して、表面に付着した硝酸銅を除去した後、径２ｍｍの球状に成形し、５００℃で１２時間焼成して、アンモニア分解触媒Ａ ４９０ｇを得た。銅の含有量は３．０質量％であった。
このアンモニア分解触媒Ａを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃、４００℃あるいは５００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１及び５，０００ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。80 g of Cu (NO 3 ) 2 .3H 2 O (manufactured by Wako Pure Chemicals, reagent special grade) is dissolved in ion exchange water to make 1 liter. To this copper nitrate solution, porous silica alumina “ZSM-5 zeolite” (Si / Al (molar ratio) = 30, specific surface area 580 m 2 / g, average particle diameter 10 μm, manufactured by Zude Chemie AG, trade name: H-MFI- 30) 500 g was dispersed and stirred at room temperature for 24 hours for ion exchange. The obtained porous silica alumina in which Cu is occluded by ion exchange is collected by filtration, washed with ion exchange water to remove copper nitrate adhering to the surface, and then molded into a spherical shape having a diameter of 2 mm, and 12 ° C. at 500 ° C. Calcination for a period of time gave 490 g of ammonia decomposition catalyst A. The copper content was 3.0% by mass.
The ammonia decomposition catalyst A was packed in a quartz reaction tube of the above atmospheric pressure flow reactor, and the reaction temperature was 300 ° C., 400 ° C. or 500 ° C., and the ammonia-containing gas flow rate (SV) was 625 hr −1 and 5,000 hr −1. The ammonia decomposition activity was evaluated. The results are shown in Table 1.
多孔質シリカアルミナとして、“βゼオライド”（Ｓｉ／Ａｌ（モル比）＝２５、比表面積２５０ｍ２／ｇ、平均粒子径３．８μｍ、ズードケミーＡＧ製、商品名：Ｈ−ＢＥＡ−２５）５００ｇを用いる他は実施例１と同様にして、銅含有量３．０質量％のアンモニア分解触媒Ｂ ４８０ｇを得た。
このアンモニア分解触媒Ｂを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。As porous silica alumina, 500 g of “β-zeolide” (Si / Al (molar ratio) = 25, specific surface area 250 m 2 / g, average particle size 3.8 μm, manufactured by Zude Chemie AG, trade name: H-BEA-25) 480 g of ammonia decomposition catalyst B having a copper content of 3.0% by mass was obtained in the same manner as in Example 1 except that it was used.
This ammonia decomposition catalyst B was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
多孔質シリカアルミナとして、“モルデナイト型ゼオライド”（Ｓｉ／Ａｌ（モル比）＝２０、比表面積４００ｍ２／ｇ、平均粒子径１０μｍ、ズードケミーＡＧ製、商品名：Ｈ−ＭＯＲ−２０）５００ｇを用いる他は実施例１と同様にして、銅含有量２．８質量％のアンモニア分解触媒Ｃ ４９０ｇを得た。
このアンモニア分解触媒Ｃを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。As the porous silica alumina, 500 g of “mordenite type zeolite” (Si / Al (molar ratio) = 20, specific surface area 400 m 2 / g, average particle diameter 10 μm, manufactured by Zude Chemie AG, trade name: H-MOR-20) is used. Others were carried out similarly to Example 1, and obtained 490g of ammonia decomposition catalysts C with a copper content of 2.8 mass%.
This ammonia decomposition catalyst C was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
多孔質シリカアルミナとして、“Ｙ型ゼオライド”（Ｓｉ／Ａｌ（モル比）＝５、比表面積２１０ｍ２／ｇ、平均粒子径１０μｍ、水澤化学製、商品名：Ｙ−４００）５００ｇを用いる他は実施例１と同様にして、銅含有量３．０質量％のアンモニア分解触媒Ｄ ４８０ｇを得た。
このアンモニア分解触媒Ｄを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。Other than using 500 g of “Y-type zeolite” (Si / Al (molar ratio) = 5, specific surface area 210 m 2 / g, average particle diameter 10 μm, manufactured by Mizusawa Chemical, trade name: Y-400) as porous silica alumina In the same manner as in Example 1, 480 g of an ammonia decomposition catalyst D having a copper content of 3.0% by mass was obtained.
This ammonia decomposition catalyst D was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Ｃｕ（ＮＯ３）２・３Ｈ２Ｏに代えて、Ｆｅ（ＮＯ３）３・９Ｈ２Ｏ（和光純薬製、試薬特級）１４０ｇを用いる他は、実施例１と同様にして、鉄含有量 ２．８質量％のアンモニア分解触媒Ｅ ４９０ｇを得た。
このアンモニア分解触媒Ｅを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通景（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。Cu (NO 3) in place of 2 · 3H 2 O, Fe ( NO 3) 3 · 9H 2 O ( manufactured by Wako Pure Chemical Industries, Ltd., guaranteed reagent) except for using a 140g, the same procedure as in Example 1, the iron content 490 g of an ammonia decomposition catalyst E of 2.8% by mass was obtained.
This ammonia decomposition catalyst E was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas distribution view (SV) 625 hr −1 at a reaction temperature of 300 ° C. to evaluate the ammonia decomposition activity. The results are shown in Table 1.
Ｃｕ（ＮＯ３）２・３Ｈ２Ｏに代えて、Ｃｏ（ＮＯ３）２・６Ｈ２Ｏ（和光純薬製、試薬特級）１００ｇを用いる他は、実施例１と同様にして、コバルト含有量３．１質量％のアンモニア分解触媒Ｆ ４９０ｇを得た。
このアンモニア分解触媒Ｆを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。Cobalt content in the same manner as in Example 1 except that 100 g of Co (NO 3 ) 2 .6H 2 O (manufactured by Wako Pure Chemicals, reagent special grade) is used instead of Cu (NO 3 ) 2 .3H 2 O 490 g of a 3.1% by mass ammonia decomposition catalyst F was obtained.
This ammonia decomposition catalyst F was packed in a quartz reaction tube of the above atmospheric pressure flow reactor, and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate the ammonia decomposition activity. The results are shown in Table 1.
Ｃｕ（ＮＯ３）２・３Ｈ２Ｏに代えて、Ｎｉ（ＮＯ３）２・６Ｈ２Ｏ（和光純薬製、試薬特級）１００ｇを用いる他は、実施例１と同様にして、ニッケル含有量２．８質量％のアンモニア分解触媒Ｇ ４９０ｇを得た。
このアンモニア分解触媒Ｇを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。Nickel content in the same manner as in Example 1 except that 100 g of Ni (NO 3 ) 2 .6H 2 O (manufactured by Wako Pure Chemicals, reagent special grade) is used instead of Cu (NO 3 ) 2 .3H 2 O 490 g of a 2.8% by mass ammonia decomposition catalyst G was obtained.
This ammonia decomposition catalyst G was packed in a quartz reaction tube of the above atmospheric pressure flow reactor, and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Ｃｕ（ＮＯ３）２・３Ｈ２Ｏに代えて、Ｚｎ（ＮＯ３）２・６Ｈ２Ｏ（和光純薬製、試薬特級）８０ｇを用いる他は、実施例１と同様にして、亜鉛含有量３．０質量％のアンモニア分解触媒Ｈ ４８０ｇを得た。
このアンモニア分解触媒Ｈを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
比較例１
アンモニア分解触媒として、市販の酸化銅−酸化マンガンの複合酸化物触媒（酸化銅含有量 ２５質量％、酸化マンガン含有量 ７５質量％、ズードケミー触媒製、商品名：Ｎ−１４０）を使用した。
複合酸化物触媒を上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
比較例２
Ｃｕ（ＮＯ３）３・３Ｈ２Ｏ（和光純薬製、試薬特級）９．２ｇをイオン交換水１００ｍｌに溶解させた水溶液を球形チタニア担体（球径２〜４ｍｍ、堺化学工業製、商品名：ＣＳ−２００−２４）１００ｇに含浸した後、５００℃で焼成して、銅／チタニア触媒（銅含有量３質量％）を得た。
この銅／チタニア触媒を上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
比較例３
アルミナ（球径１〜２ｍｍ、住友化学工業製、商品名：ＮＫＨＤ−１２）１００ｇに塩化パラジウムパラジウム（和光純薬製、試薬特級）０．１ｇ（金属Ｐｄとして）をイオン交換水１０ｍｌに溶解した溶液を含浸し、５００℃で焼成した。焼成物をヒドラジン１ｇ含む水溶液５００ｍｌ分散させ、液相還元して、パラジウム／アルミナ触媒を得た。
このパラジウム／アルミナ触媒を上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
比較例４
実施例１で用いたＺＳＭ−５ゼオライト９４ｇに銅３ｇを含む硝酸銅水溶液３０ｍｌを使用して、含浸法で銅を担持し、５００℃で焼成して、含浸法アンモニア分解触媒Ｉを得た。
このアンモニア分解触媒Ｉを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
比較例５
多孔質シリカアルミナとして、“ＺＳＭ−５ゼオライト”（Ｓｉ／Ａｌ（モル比）＝９５、比表面積４００ｍ２／ｇ、平均粒子径７０μｍ、ズードケミーＡＧ製、商品名：Ｈ−ＭＦＩ−９０）５００ｇを用いる他は実施例１と同様にして、銅含有量２．３質量％のアンモニア分解触媒Ｊ ４８０ｇを得た。
このアンモニア分解触媒Ｊを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
比較例６
多孔質シリカアルミナとして、“βゼオライド”（Ｓｉ／Ａｌ（モル比）＝１５０、比表面積６２０ｍ２／ｇ、平均粒子径４５μｍ、ズードケミーＡＧ製、商品名：Ｈ−ＢＥＡ−１５０）５００ｇを用いる他は実施例１と同様にして、銅含有量１．８質量％のアンモニア分解触媒Ｋ ４９０ｇを得た。
このアンモニア分解触媒Ｋを上記常圧流通式反応装置の石英製反応管に詰め、反応温度３００℃で、アンモニア含有ガス流通量（ＳＶ）６２５ｈｒ−１で通し、アンモニア分解活性を評価した。結果を第１表に示した。
This ammonia decomposition catalyst H was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Comparative Example 1
As the ammonia decomposition catalyst, a commercially available composite oxide catalyst of copper oxide-manganese oxide (copper oxide content 25 mass%, manganese oxide content 75 mass%, manufactured by Zude Chemie Catalysts, trade name: N-140) was used.
The complex oxide catalyst was packed in a quartz reaction tube of the above atmospheric pressure flow reactor, and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Comparative Example 2
Cu (NO 3) 3 · 3H 2 O ( manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent) 9.2 g aqueous solution prepared by dissolving in ion-exchanged water 100ml the spherical titania carrier (spherical diameter 2-4 mm, manufactured by Sakai Chemical Industry Co., trade name : CS-200-24) After impregnating 100 g, it was baked at 500 ° C. to obtain a copper / titania catalyst (copper content 3 mass%).
This copper / titania catalyst was packed in a quartz reaction tube of the above normal pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Comparative Example 3
Palladium chloride palladium (manufactured by Wako Pure Chemicals, reagent grade) 0.1 g (as metal Pd) was dissolved in 10 ml of ion-exchanged water in 100 g of alumina (sphere diameter 1 to 2 mm, manufactured by Sumitomo Chemical Co., Ltd., trade name: NKHD-12). The solution was impregnated and baked at 500 ° C. 500 ml of an aqueous solution containing 1 g of hydrazine was dispersed in the calcined product and subjected to liquid phase reduction to obtain a palladium / alumina catalyst.
This palladium / alumina catalyst was packed in a quartz reaction tube of the above normal pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Comparative Example 4
Using 94 ml of ZSM-5 zeolite used in Example 1 and 30 ml of an aqueous copper nitrate solution containing 3 g of copper, copper was supported by an impregnation method and calcined at 500 ° C. to obtain an impregnation method ammonia decomposition catalyst I.
This ammonia decomposition catalyst I was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
Comparative Example 5
As porous silica alumina, “ZSM-5 zeolite” (Si / Al (molar ratio) = 95, specific surface area 400 m 2 / g, average particle diameter 70 μm, manufactured by Zude Chemie AG, trade name: H-MFI-90) 500 g 480 g of ammonia decomposition catalyst J having a copper content of 2.3 mass% was obtained in the same manner as in Example 1 except that it was used.
This ammonia decomposition catalyst J was packed in a quartz reaction tube of the above normal pressure flow type reaction apparatus, and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate the ammonia decomposition activity. The results are shown in Table 1.
Comparative Example 6
Other than using 500 g of “β-zeolide” (Si / Al (molar ratio) = 150, specific surface area 620 m 2 / g, average particle size 45 μm, manufactured by Zude Chemie AG, trade name: H-BEA-150) as porous silica alumina Produced 490 g of an ammonia decomposition catalyst K having a copper content of 1.8% by mass in the same manner as in Example 1.
This ammonia decomposition catalyst K was packed in a quartz reaction tube of the above atmospheric pressure flow reactor and passed through an ammonia-containing gas flow rate (SV) of 625 hr −1 at a reaction temperature of 300 ° C. to evaluate ammonia decomposition activity. The results are shown in Table 1.
本発明のアンモニア分解触媒は、アンモニアを％オーダーの濃度で含むガス中のアンモニアを略完全に分解することが可能であり、高温でのアンモニアの分解であっても、酸化窒素のような有害成分が発生しない。したがって、本発明のアンモニア分解触媒および該触媒を用いるアンモニアの分解方法は、アンモニアを高濃度に含有する排ガスの除害に有用であり、その産業上への寄与は絶大である。 The ammonia decomposition catalyst of the present invention is capable of substantially completely decomposing ammonia in a gas containing ammonia in a concentration on the order of%. Even when decomposing ammonia at a high temperature, harmful components such as nitric oxide are used. Does not occur. Therefore, the ammonia decomposition catalyst and the ammonia decomposition method using the catalyst of the present invention are useful for detoxification of exhaust gas containing ammonia at a high concentration, and the contribution to the industry is tremendous.
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| JP4775697B2 (en) * | 2005-07-20 | 2011-09-21 | 宇部興産株式会社 | Oxidative treatment method and apparatus for exhaust gas |
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