JP2007313410A - Ammonia decomposition catalyst and ammonia treating method - Google Patents
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本発明は、各種排ガス中に含まれるアンモニアを無害な窒素に分解するアンモニア分解触媒、及びそのアンモニア分解触媒を用いた排ガス中のアンモニア処理方法に関する。 The present invention relates to an ammonia decomposition catalyst that decomposes ammonia contained in various exhaust gases into harmless nitrogen, and a method for treating ammonia in exhaust gases using the ammonia decomposition catalyst.
火力発電設備、下水処理設備、アミン製造設備、食品製造設備、し尿処理設備、コークス炉製造設備などから排出される排ガス中のアンモニアは有害物質であり、これら設備の配管を腐食するなど悪影響が大きい。そのため、これらの排ガス中のアンモニアを効率よく除去する技術の開発が望まれている。 Ammonia in exhaust gas discharged from thermal power generation equipment, sewage treatment equipment, amine production equipment, food production equipment, human waste treatment equipment, coke oven production equipment, etc. is a harmful substance, and it has a bad influence such as corroding the piping of these equipment. . Therefore, development of a technique for efficiently removing ammonia in these exhaust gases is desired.
排ガス中のアンモニアを除去する方法として、例えば、特公昭５７−０５８２１３号公報、特開平０２−１９８６３８号公報、特公平０６−００４１３８号公報、特開平０７−３２８４４０号公報などには、白金、パラジウムなどの貴金属をアルミナ、シリカ、チタニアなどの担体に担持した貴金属系触媒を用いる方法や、銅、ニッケル、コバルトなどの酸化物を触媒活性成分として分散担持したアンモニア分解触媒を用いる方法が提案されている。 As a method for removing ammonia in exhaust gas, for example, Japanese Patent Publication No. 57-058213, Japanese Patent Application Laid-Open No. 02-198638, Japanese Patent Publication No. 06-004138, Japanese Patent Application Laid-Open No. 07-328440, etc. include platinum, palladium A method using a noble metal catalyst in which a noble metal such as alumina, silica or titania is supported and a method using an ammonia decomposition catalyst in which an oxide such as copper, nickel or cobalt is dispersed and supported as a catalyst active component have been proposed. Yes.
しかし、上記した従来のアンモニア分解触媒は、高温条件下やアンモニア濃度に対する酸素過剰条件下では、アンモニアの酸化によって大気汚染物質である窒素酸化物ＮＯｘが多量に発生するという欠点があった。しかも、白金やパラジウムなどの貴金属系触媒は、コストが高くなるなどの問題もあった。また、銅やニッケルなどの卑金属酸化物系触媒は、低温での活性が低く、その場合に大気汚染物質であるＮＯｘやＮ２Ｏの発生を招くという問題があった。 However, the conventional ammonia decomposition catalyst described above has a drawback that a large amount of nitrogen oxide NOx, which is an air pollutant, is generated due to oxidation of ammonia under high temperature conditions or oxygen excess conditions with respect to ammonia concentration. In addition, noble metal catalysts such as platinum and palladium have a problem of high cost. In addition, base metal oxide catalysts such as copper and nickel have low activity at low temperatures, and in this case, there is a problem in that NOx and N 2 O, which are air pollutants, are generated.
そこで、アンモニア分解時における窒素酸化物ＮＯｘの副生を防止するため、例えば、特開平０５−１４６６３４号公報、特開平０８−１３１８３２号公報、特開２００３−２４７８４号公報、特開２００３−２０００５０号公報には、チタン、バナジウム、タングステン、モリブデンなどの脱硝触媒成分と、白金、パラジウム、ロジウムなどの酸化触媒成分とを組み合わせたアンモニア分解触媒が提案されている。 Therefore, in order to prevent the generation of nitrogen oxides NOx during ammonia decomposition, for example, Japanese Patent Laid-Open Nos. 05-146634, 08-131832, 2003-24784, and 2003-200050 are disclosed. The publication proposes an ammonia decomposition catalyst that combines a denitration catalyst component such as titanium, vanadium, tungsten, and molybdenum and an oxidation catalyst component such as platinum, palladium, and rhodium.
しかしながら、このようなアンモニア分解触媒は、酸化触媒成分が貴金属を含むため高価であるという問題があった。そのため、貴金属を含まず安価であって、アンモニアを効率よく分解することができるだけでなく、大気汚染物質であるＮＯｘやＮ２Ｏの発生の副生を抑えることができるアンモニア分解触媒の提供が望まれていた。 However, such an ammonia decomposition catalyst has a problem that it is expensive because the oxidation catalyst component contains a noble metal. Therefore, it is desirable to provide an ammonia decomposition catalyst that does not contain precious metals, is inexpensive, can not only efficiently decompose ammonia, but also can suppress by-product generation of NOx and N 2 O, which are air pollutants. It was rare.
本発明は、このような従来の事情に鑑み、大気汚染のもととなる窒素酸化物のＮＯｘやＮ２Ｏの副生を極力抑え、排ガス中のアンモニアを効率よく窒素に分解除去することのできるアンモニア分解触媒、及びその触媒を使用したアンモニア処理方法を提供することを目的とする。 In view of such conventional circumstances, the present invention suppresses as much as possible NOx and N 2 O by-products of nitrogen oxides that cause air pollution, and efficiently decomposes and removes ammonia in exhaust gas into nitrogen. It is an object of the present invention to provide an ammonia decomposition catalyst that can be used and an ammonia treatment method using the catalyst.
上記目的を達成するため、本発明が提供するアンモニア分解触媒は、酸化マンガンと、酸化セリウムと、アルミナと、ゼオライトを含有することを特徴とするものである。上記本発明のアンモニア分解触媒においては、酸化マンガンの含有量がＭｎＯ２換算で１〜６０重量％であり、酸化セリウムの含有量がＣｅＯ２換算で１〜３０重量％、及びアルミナの含有量が１０〜７０重量％であることが好ましい。 In order to achieve the above object, the ammonia decomposition catalyst provided by the present invention is characterized by containing manganese oxide, cerium oxide, alumina, and zeolite. In the ammonia decomposition catalyst of the present invention, the content of manganese oxide is 1 to 60% by weight in terms of MnO 2 , the content of cerium oxide is 1 to 30% by weight in terms of CeO 2 , and the content of alumina is It is preferably 10 to 70% by weight.
また、本発明が提供するアンモニア処理方法は、排ガス中のアンモニアを触媒により分解して除去するアンモニア処理方法であって、上記本発明のアンモニア分解触媒、即ち、酸化マンガンと、酸化セリウムと、アルミナと、ゼオライトを含有することを特徴とするアンモニア分解触媒を用いることを特徴とする。 The ammonia treatment method provided by the present invention is an ammonia treatment method in which ammonia in exhaust gas is decomposed and removed by a catalyst, and the ammonia decomposition catalyst of the present invention, that is, manganese oxide, cerium oxide, and alumina. And an ammonia decomposition catalyst characterized by containing zeolite.
本発明によれば、高温や低温などの温度条件にかかわらず、また排ガス中のアンモニア濃度に対して酸素過剰の条件下であっても、大気汚染のもととなるＮＯやＮＯ２のような窒素酸化物ＮＯｘ及びＮ２Ｏの副生を極力抑えながら、排ガス中のアンモニアを効率よく窒素に分解して除去することができ、貴金属を含まない安価な触媒を提供することができる。 According to the present invention, regardless of the temperature conditions such as high or low temperature, also be oxygen excess conditions to ammonia concentration in the exhaust gas, such as NO and NO 2 as a source of air pollution While suppressing by-products of nitrogen oxides NOx and N 2 O as much as possible, ammonia in the exhaust gas can be efficiently decomposed and removed into nitrogen, and an inexpensive catalyst containing no precious metal can be provided.
本発明のアンモニア分解触媒は、酸化マンガンと、酸化セリウムと、アルミナと、ゼオライトとを含むものである。酸化マンガンと酸化セリウムとアルミナとゼオライトは単に混合された状態でもよいし、酸化マンガンと酸化セリウムがアルミナとゼオライトに担持された状態であってもよい。 The ammonia decomposition catalyst of the present invention contains manganese oxide, cerium oxide, alumina, and zeolite. Manganese oxide, cerium oxide, alumina, and zeolite may be simply mixed, or manganese oxide and cerium oxide may be supported on alumina and zeolite.
アンモニア分解触媒中における酸化マンガンの含有量は、ＭｎＯ２換算で触媒全体に対して１〜６０重量％の範囲が好ましい。上記酸化マンガンの含有量がＭｎＯ２として１重量％未満では、十分なアンモニア分解能が得られない。酸化マンガン含有量の増加に伴ってアンモニア分解能も向上するが、６０重量％を超えるとアンモニアの酸化によって大気汚染物質であるＮＯｘやＮ２Ｏの副生が顕著に増加するため好ましくない。 The content of manganese oxide in the ammonia decomposition catalyst is preferably in the range of 1 to 60% by weight in terms of MnO 2 with respect to the whole catalyst. If the manganese oxide content is less than 1% by weight as MnO 2 , sufficient ammonia resolution cannot be obtained. As the manganese oxide content increases, the ammonia resolution also improves. However, if it exceeds 60% by weight, by-production of NOx and N 2 O that are air pollutants remarkably increases due to the oxidation of ammonia, it is not preferable.
また、アンモニア分解触媒中における酸化セリウムの含有量は、ＣｅＯ２換算で触媒全体に対して１〜３０重量％であることが好ましい。上記酸化セリウムの含有量がＣｅＯ２換算で１重量％未満では、添加によるアンモニアの分解効果が充分に得られない。逆に酸化セリウム含有量が３０重量％を超えると、アンモニアの酸化によって大気汚染物質であるＮＯｘやＮ２Ｏの副生が顕著に増加するため好ましくない。 The content of cerium oxide in the ammonia decomposition catalyst is preferably 1 to 30 wt% based on the total catalyst in terms of CeO 2. When the content of the cerium oxide is less than 1% by weight in terms of CeO 2 , the ammonia decomposition effect due to addition cannot be sufficiently obtained. On the other hand, if the cerium oxide content exceeds 30% by weight, by-production of NOx and N 2 O, which are air pollutants, is remarkably increased due to the oxidation of ammonia.
更に、アンモニア分解触媒中におけるアルミナ（Ａｌ２Ｏ３）の含有量は、触媒全体に対して１０〜７０重量％であることが好ましい。上記アルミナの含有量が１０重量％未満では、触媒全体の価格を低減させる効果が小さいため好ましくない。逆にアルミナ含有量が７０重量％を超えると、アンモニアの酸化によって大気汚染物質であるＮＯｘやＮ２Ｏの副生が顕著に増加するため好ましくない。 Furthermore, the content of alumina (Al 2 O 3 ) in the ammonia decomposition catalyst is preferably 10 to 70% by weight based on the whole catalyst. If the alumina content is less than 10% by weight, the effect of reducing the price of the entire catalyst is small, such being undesirable. On the other hand, if the alumina content exceeds 70% by weight, by-production of NOx and N 2 O, which are air pollutants, is remarkably increased due to the oxidation of ammonia.
本発明のアンモニア分解触媒に用いるアルミナとしては、特に限定されるものではないが、例えば、γ−アルミナなどを好適に使用することができる。また、ゼオライトの種類については、特に限定されるものではないが、βゼオライト、フェリエライト、モルデナイト、ＺＳＭ−５、Ｙゼオライトなどを好適に使用することができる。また、使用するゼオライトのＳｉＯ２／Ａｌ２Ｏ３モル比は１０以上であることが好ましく、より十分な耐久性が得られるという点で１０〜６００の範囲が更に好ましい。尚、これらのゼオライトの製造法については、特に限定されるものではない。 Although it does not specifically limit as an alumina used for the ammonia decomposition catalyst of this invention, For example, (gamma) -alumina etc. can be used conveniently. Further, the type of zeolite is not particularly limited, but β zeolite, ferrierite, mordenite, ZSM-5, Y zeolite and the like can be suitably used. Also, SiO 2 / Al 2 O 3 molar ratio of the zeolite used is preferably 10 or more, the range of 10 to 600 is more preferable in that more sufficient durability can be obtained. In addition, it does not specifically limit about the manufacturing method of these zeolites.
本発明のアンモニア分解触媒において、酸化マンガン、酸化セリウム、アルミナ、及びゼオライトを含有させる方法は特に限定されず、従来から知られている方法を用いることができる。例えば、酸化マンガンと酸化セリウムとアルミナとゼオライトの混合状態の触媒を得るには、酸化マンガン粉末と酸化セリウム粉末とアルミナ粉末とゼオライト粉末を機械的に混合する物理混合法などを用いることができる。 In the ammonia decomposition catalyst of the present invention, the method of containing manganese oxide, cerium oxide, alumina, and zeolite is not particularly limited, and a conventionally known method can be used. For example, in order to obtain a mixed catalyst of manganese oxide, cerium oxide, alumina, and zeolite, a physical mixing method in which manganese oxide powder, cerium oxide powder, alumina powder, and zeolite powder are mechanically mixed can be used.
また、アルミナ及びゼオライトに、酸化マンガンと酸化セリウムを担持させる場合には、例えば、アルミナ粉末とゼオライト粉末を機械的に混合し、この粉末にマンガンとセリウムの水溶性塩の水溶液を含浸させる含浸法などを用いることができる。この方法では、酸化マンガンと酸化セリウムとアルミナとゼオライトを含有させた後、乾燥・焼成することによって、本発明のアンモニア分解触媒を調製することができる。 In the case of supporting manganese oxide and cerium oxide on alumina and zeolite, for example, an impregnation method in which alumina powder and zeolite powder are mechanically mixed and impregnated with an aqueous solution of a water-soluble salt of manganese and cerium. Etc. can be used. In this method, the ammonia decomposition catalyst of the present invention can be prepared by adding manganese oxide, cerium oxide, alumina, and zeolite, followed by drying and firing.
上記した触媒調製時の乾燥温度は、特に限定されるものではないが、通常８０〜１２０℃程度で乾燥する。また、焼成温度は３００〜１０００℃程度が好ましく、４００〜８００℃程度が更に好ましい。この乾燥時及び焼成時の雰囲気については、触媒組成に応じて、大気雰囲気、不活性ガス雰囲気、酸素雰囲気、水蒸気雰囲気などの各雰囲気を適宜選択すればよく、これらの各雰囲気を一定時間毎に交互に代えて用いることもできる。 Although the drying temperature at the time of catalyst preparation described above is not particularly limited, it is usually dried at about 80 to 120 ° C. Moreover, about 300-1000 degreeC is preferable for baking temperature, and about 400-800 degreeC is still more preferable. About the atmosphere at the time of drying and calcination, each atmosphere such as an air atmosphere, an inert gas atmosphere, an oxygen atmosphere, and a water vapor atmosphere may be appropriately selected according to the catalyst composition. It can also be used alternately.
本発明によるアンモニア分解触媒は、従来知られている成形方法によって、球状、ハニカム状、ペレット状など、種々の形状に成形することができる。これらの形状並びに大きさなどは、使用条件に応じて任意に選択すればよい。また、排ガスの流れ方向に対して多数の貫通孔を有する耐火性一体構造の支持基体の表面に、ウォッシュコート法などによりアンモニア分解触媒を被覆することも可能である。 The ammonia decomposition catalyst according to the present invention can be formed into various shapes such as a spherical shape, a honeycomb shape, and a pellet shape by a conventionally known forming method. These shapes and sizes may be arbitrarily selected according to use conditions. It is also possible to coat an ammonia decomposition catalyst by a wash coat method or the like on the surface of a support base having a fireproof integrated structure having a large number of through holes in the flow direction of the exhaust gas.
本発明のアンモニア分解触媒を排ガスと接触させることによって、排ガス中のアンモニアを酸化分解して除去することができる。アンモニアを含む排ガスを処理する際のガス空間速度（ＳＶ）については、特に限定されるものではないが、ＳＶ１,０００〜１００,０００ｈ−１の範囲とすることが好ましい。また、アンモニア分解の反応温度は２００〜５００℃程度でよく、特に３００〜４００℃の範囲が好ましい。 By bringing the ammonia decomposition catalyst of the present invention into contact with exhaust gas, ammonia in the exhaust gas can be oxidized and removed. Although it does not specifically limit about the gas space velocity (SV) at the time of processing the waste gas containing ammonia, It is preferable to set it as the range of SV1,000-100,000h- 1 . Moreover, the reaction temperature of ammonia decomposition may be about 200 to 500 ° C., and the range of 300 to 400 ° C. is particularly preferable.
［本発明のアンモニア分解触媒の調製］
３０ｇのイオン交換水に、硝酸マンガン(II)六水和物６.７ｇと硝酸セリウム(III)六水和物５.１ｇを溶解し、この溶液にＳｉＯ２／Ａｌ２Ｏ３モル比２０のモルデナイト粉末１０ｇとアルミナ粉末６ｇをメノー乳鉢にて物理混合した粉末を浸漬した後、溶液を撹拌しながら加熱して水分を蒸発させ、更に１１０℃で通風乾燥し、次に大気中にて５００℃で３時間焼成した。これを加圧成型した後、粉砕して粒度を３５０〜５００μｍに整粒し、酸化マンガンの含有量がＭｎＯ２換算で触媒全体の１０重量％、酸化セリウムの含有量がＣｅＯ２換算で触媒全体の１０重量％、アルミナの含有量が触媒全体の３０重量％である本発明の触媒１を得た。
[Preparation of ammonia decomposition catalyst of the present invention]
In 30 g of ion-exchanged water, 6.7 g of manganese (II) nitrate hexahydrate and 5.1 g of cerium (III) nitrate hexahydrate were dissolved, and the SiO 2 / Al 2 O 3 molar ratio of 20 was dissolved in this solution. After immersing a powder obtained by physically mixing 10 g of mordenite powder and 6 g of alumina powder in a menor mortar, the solution is heated with stirring to evaporate water, further dried by ventilation at 110 ° C., and then at 500 ° C. in the air. For 3 hours. This is pressure-molded and then pulverized to adjust the particle size to 350 to 500 μm. The manganese oxide content is 10% by weight of the total catalyst in terms of MnO 2 and the cerium oxide content is in terms of CeO 2 to represent the entire catalyst. Thus, the catalyst 1 of the present invention having an alumina content of 30% by weight of the total catalyst was obtained.
また、上記触媒１と同様にアンモニア分解触媒を調製する際に、酸化マンガンの含有量をＭｎＯ２換算で触媒全体の１重量％とした以外は上記触媒１の場合と同様にして、本発明の触媒２を得た。尚、この触媒２において、酸化セリウムの含有量はＣｅＯ２換算で触媒全体の１０重量％、アルミナの含有量は触媒全体の３０重量％である。 Further, when the ammonia decomposition catalyst was prepared in the same manner as the catalyst 1, the content of manganese oxide was changed to 1% by weight of the whole catalyst in terms of MnO 2 , and the same as in the case of the catalyst 1, Catalyst 2 was obtained. In this catalyst 2, the content of cerium oxide is 10% by weight in terms of CeO 2 and the content of alumina is 30% by weight of the whole catalyst.
上記触媒１と同様にアンモニア分解触媒を調製する際に、酸化セリウムの含有量をＣｅＯ２換算で触媒全体の１重量％とした以外は上記触媒１の場合と同様にして、本発明の触媒３を得た。また、同じく酸化セリウムの含有量をＣｅＯ２換算で触媒全体の３０重量％とした以外は上記触媒1の場合と同様にして、本発明の触媒４を得た。これらの触媒３及び触媒４において、酸化マンガンの含有量はＭｎＯ２換算で触媒全体の１０重量％、アルミナの含有量は触媒全体の３０重量％である。 The catalyst 3 of the present invention was prepared in the same manner as in the case of the catalyst 1 except that the ammonia decomposition catalyst was prepared in the same manner as the catalyst 1 except that the content of cerium oxide was 1% by weight in terms of CeO 2. Got. Similarly, the catalyst 4 of the present invention was obtained in the same manner as in the case of the catalyst 1 except that the content of cerium oxide was 30% by weight in terms of CeO 2 with respect to the whole catalyst. In these catalysts 3 and 4, the manganese oxide content is 10% by weight of the whole catalyst in terms of MnO 2 , and the alumina content is 30% by weight of the whole catalyst.
上記触媒１と同様にアンモニア分解触媒を調製する際に、アルミナの含有量を触媒全体の１０重量％とした以外は上記触媒１の場合と同様にして、本発明の触媒５を得た。また、同じくアルミナの含有量を触媒全体の７０重量％とした以外は上記触媒1の場合と同様にして、本発明の触媒６を得た。これらの触媒５及び触媒６において、酸化マンガンの含有量はＭｎＯ２換算で触媒全体の１０重量％、酸化セリウムの含有量はＣｅＯ２換算で触媒全体の１０重量％である。 The catalyst 5 of the present invention was obtained in the same manner as in the case of the catalyst 1 except that the ammonia decomposition catalyst was prepared in the same manner as the catalyst 1 except that the alumina content was 10% by weight of the total catalyst. Similarly, the catalyst 6 of the present invention was obtained in the same manner as in the case of the catalyst 1 except that the content of alumina was set to 70% by weight of the whole catalyst. In these catalysts 5 and 6, the manganese oxide content is 10% by weight of the whole catalyst in terms of MnO 2 , and the cerium oxide content is 10% by weight of the whole catalyst in terms of CeO 2 .
上記触媒１と同様にアンモニア分解触媒を調製する際に、モルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比１５０のβゼオライトを用いた以外は上記触媒１の場合と同様にして、本発明の触媒７を得た。また、同じくモルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比８０のＺＳＭ−５を用いた以外は上記触媒１の場合と同様にして、本発明の触媒８を得た。更に、同じくモルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比５６０のＹゼオライトを用いた以外は上記触媒１の場合と同様にして、本発明の触媒９を得た。これらの触媒７〜９において、酸化マンガンの含有量はＭｎＯ２換算で触媒全体の１０重量％、酸化セリウムの含有量はＣｅＯ２換算で触媒全体の１０重量％、アルミナの含有量は触媒全体の３０重量％である。 When preparing an ammonia decomposition catalyst in the same manner as in the above catalyst 1, in the same manner as in the above catalyst 1 except that β zeolite having a SiO 2 / Al 2 O 3 molar ratio of 150 was used instead of mordenite, Catalyst 7 was obtained. Similarly, catalyst 8 of the present invention was obtained in the same manner as in catalyst 1 except that ZSM-5 having a SiO 2 / Al 2 O 3 molar ratio of 80 was used instead of mordenite. Further, a catalyst 9 of the present invention was obtained in the same manner as in the case of the catalyst 1 except that Y zeolite having a SiO 2 / Al 2 O 3 molar ratio of 560 was used instead of mordenite. In these catalysts 7 to 9, the content of manganese oxide is 10% by weight of the whole catalyst in terms of MnO 2 , the content of cerium oxide is 10% by weight of the whole catalyst in terms of CeO 2 , and the content of alumina is the amount of the whole catalyst 30% by weight.
次に、ＳｉＯ２／Ａｌ２Ｏ３モル比２０のモルデナイト粉末１０ｇと、アルミナ粉末６ｇと、二酸化マンガン粉末２ｇと、二酸化セリウム粉末２ｇとを、メノー乳鉢にて物理混合した。この混合物を加圧成型した後、粉砕して粒度を３５０〜５００μｍに整粒し、本発明による触媒１０とした。尚、この触媒１０において、酸化マンガンの含有量はＭｎＯ２換算で触媒全体の１０重量％、酸化セリウムの含有量はＣｅＯ２換算で触媒全体の１０重量％、アルミナの含有量は触媒全体の３０重量％である。 Next, 10 g of mordenite powder having a SiO 2 / Al 2 O 3 molar ratio of 20, 6 g of alumina powder, 2 g of manganese dioxide powder, and 2 g of cerium dioxide powder were physically mixed in a menor mortar. This mixture was pressure-molded and then pulverized to adjust the particle size to 350 to 500 μm to obtain the catalyst 10 according to the present invention. In addition, in this catalyst 10, the manganese oxide content is 10% by weight of the whole catalyst in terms of MnO 2 , the cerium oxide content is 10% by weight in terms of CeO 2 , and the alumina content is 30% of the whole catalyst. % By weight.
上記触媒１０と同様にアンモニア分解触媒を調製する際に、酸化マンガンの含有量をＭｎＯ２換算で触媒全体の６０重量％、アルミナの含有量を２０重量％とした以外は上記触媒１０の場合と同様にして、本発明の触媒１１を得た。また、同じく酸化セリウムの含有量をＣｅＯ２換算で触媒全体の３０重量％とした以外は上記触媒１０の場合と同様にして、本発明の触媒１２を得た。更に、同じくアルミナの含有量を触媒全体の７０重量％とした以外は上記触媒１０の場合と同様にして、本発明の触媒１３を得た。 When preparing the ammonia decomposition catalyst in the same manner as the catalyst 10, the catalyst 10 except that the manganese oxide content is 60% by weight of the total catalyst and the alumina content is 20% by weight in terms of MnO 2. Similarly, catalyst 11 of the present invention was obtained. Similarly, the catalyst 12 of the present invention was obtained in the same manner as in the case of the catalyst 10 except that the content of cerium oxide was changed to 30% by weight in terms of CeO 2 . Furthermore, the catalyst 13 of the present invention was obtained in the same manner as in the case of the catalyst 10 except that the content of alumina was also set to 70% by weight of the whole catalyst.
上記触媒１０と同様にアンモニア分解触媒を調製する際に、モルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比１５０のβゼオライトを用いた以外は上記触媒１０の場合と同様にして、本発明の触媒１４を得た。また、同じくモルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比８０のＺＳＭ−５を用いた以外は上記触媒１０の場合と同様にして、本発明の触媒１５を得た。更に、同じくモルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比５６０のＹゼオライトを用いた以外は上記触媒１０の場合と同様にして、本発明の触媒１６を得た。これらの触媒１４〜１６において、酸化マンガンの含有量はＭｎＯ２換算で触媒全体の１０重量％、酸化セリウムの含有量はＣｅＯ２換算で触媒全体の１０重量％、アルミナの含有量は触媒全体の３０重量％である。 When preparing an ammonia decomposition catalyst in the same manner as the catalyst 10, the same procedure as in the case of the catalyst 10 except that β zeolite having a SiO 2 / Al 2 O 3 molar ratio of 150 was used instead of mordenite. Catalyst 14 was obtained. Similarly, catalyst 15 of the present invention was obtained in the same manner as in the case of catalyst 10 except that ZSM-5 having a SiO 2 / Al 2 O 3 molar ratio of 80 was used instead of mordenite. Further, a catalyst 16 of the present invention was obtained in the same manner as in the case of the catalyst 10 except that Y zeolite having a SiO 2 / Al 2 O 3 molar ratio of 560 was used instead of mordenite. In these catalysts 14 to 16, the content of manganese oxide is 10% by weight of the whole catalyst in terms of MnO 2 , the content of cerium oxide is 10% by weight of the whole catalyst in terms of CeO 2 , and the content of alumina is the amount of the whole catalyst 30% by weight.
［比較例のアンモニア分解触媒の調製］
上記触媒１と同様にアンモニア分解触媒を調製する際に、酸化マンガンの含有量をＭｎＯ２換算で触媒全体の０.１重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ１を得た。また、上記触媒１０と同様にアンモニア分解触媒を調製する際に、酸化マンガンの含有量をＭｎＯ２換算で触媒全体の７０重量％、アルミナの含有量を触媒全体の１０重量％とした以外は上記触媒１０の場合と同様にして、比較例の触媒Ｃ２を得た。
[Preparation of Comparative Example Ammonia Decomposition Catalyst]
When preparing an ammonia decomposition catalyst in the same manner as in the above catalyst 1, the content of manganese oxide was 0.1% by weight of the whole catalyst in terms of MnO 2 , and the same as in the case of the above catalyst 1, Catalyst C1 was obtained. Further, when preparing an ammonia decomposition catalyst in the same manner as the catalyst 10 described above, except that the manganese oxide content was 70% by weight of the whole catalyst in terms of MnO 2 and the alumina content was 10% by weight of the whole catalyst. In the same manner as in the case of the catalyst 10, a comparative catalyst C2 was obtained.
上記触媒１と同様にアンモニア分解触媒を調製する際に、酸化セリウムの含有量をＣｅＯ２換算で触媒全体の０.１重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ３を得た。また同様に、酸化セリウムの含有量をＣｅＯ２換算で触媒全体の４０重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ４を得た。 When preparing an ammonia decomposition catalyst in the same manner as in the above catalyst 1, the same procedure as in the above catalyst 1 was repeated except that the content of cerium oxide was 0.1% by weight of the total catalyst in terms of CeO 2 . Catalyst C3 was obtained. Similarly, a catalyst C4 of a comparative example was obtained in the same manner as in the case of the catalyst 1 except that the content of cerium oxide was 40% by weight in terms of CeO 2 with respect to the whole catalyst.
上記触媒１と同様にアンモニア分解触媒を調製する際に、モルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比１５０のβゼオライトを用い、且つ酸化マンガンの含有量をＭｎＯ２換算で触媒全体の０.１重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ５を得た。また、同じくモルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比８０のＺＳＭ−５を用い、且つ酸化セリウムの含有量をＣｅＯ２換算で触媒全体の４０重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ６を得た。更に、同じくモルデナイトに代えてＳｉＯ２／Ａｌ２Ｏ３モル比５６０のＹゼオライトを用い、且つ酸化セリウムの含有量をＣｅＯ２換算で触媒全体の４０重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ７を得た。 When preparing an ammonia decomposition catalyst in the same manner as the catalyst 1, β zeolite having a SiO 2 / Al 2 O 3 molar ratio of 150 is used instead of mordenite, and the manganese oxide content is 0% of the total catalyst in terms of MnO 2. A comparative catalyst C5 was obtained in the same manner as in the case of the catalyst 1 except that the amount was changed to 0.1% by weight. Similarly, in the case of the catalyst 1 except that ZSM-5 having a SiO 2 / Al 2 O 3 molar ratio of 80 is used instead of mordenite, and the content of cerium oxide is 40% by weight in terms of CeO 2 In the same manner as described above, Comparative Example C6 was obtained. Further, in the case of the catalyst 1 except that Y zeolite having a SiO 2 / Al 2 O 3 molar ratio of 560 is used instead of mordenite, and the content of cerium oxide is 40% by weight in terms of CeO 2. Similarly, a catalyst C7 of Comparative Example was obtained.
次に、３０gのイオン交換水に硝酸セリウム(III)六水和物４.３ｇを溶解し、この溶液にＳｉＯ２／Ａｌ２Ｏ３モル比２０のモルデナイト１０gとアルミナ５ｇをメノー乳鉢にて物理混合した粉末を浸漬した後、撹拌しながら加熱して水分を蒸発させ、更に１１０℃で通風乾燥した後、空気中にて５００℃で３時間焼成した以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ８を得た。尚、この比較例の触媒Ｃ８は、酸化マンガンを含まず、酸化セリウムの含有量はＣｅＯ２換算で触媒全体の１０重量％、及びアルミナの含有量は触媒全体の３０重量％である。 Next, 4.3 g of cerium (III) nitrate hexahydrate was dissolved in 30 g of ion-exchanged water, and 10 g of mordenite having a SiO 2 / Al 2 O 3 molar ratio of 20 and 5 g of alumina were physically added to this solution in a menor mortar. After immersing the mixed powder, the mixture was heated with stirring to evaporate the moisture, further dried by ventilation at 110 ° C., and then calcined in air at 500 ° C. for 3 hours in the same manner as in the case of Catalyst 1 above. A catalyst C8 of Comparative Example was obtained. The catalyst C8 of this comparative example does not contain manganese oxide, the content of cerium oxide is 10% by weight in terms of CeO 2 , and the content of alumina is 30% by weight of the whole catalyst.
また、３０gのイオン交換水に硝酸マンガン(II)六水和物５.６ｇを溶解し、この溶液にＳｉＯ２／Ａｌ２Ｏ３モル比２０のモルデナイト１０gとアルミナ５ｇとをメノー乳鉢にて物理混合した粉末を浸漬した後、撹拌しながら加熱して水分を蒸発させ、更に１１０℃で通風乾燥した後、空気中にて５００℃で３時間焼成した以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ９を得た。尚、この比較例の触媒Ｃ９は、酸化セリウムを含まず、酸化マンガンの含有量がＭｎＯ２換算で触媒全体の１０重量％、アルミナの含有量は触媒全体の３０重量％である。 Further, 5.6 g of manganese (II) nitrate hexahydrate was dissolved in 30 g of ion-exchanged water, and 10 g of mordenite having a SiO 2 / Al 2 O 3 molar ratio of 20 and 5 g of alumina were physically added to this solution in a menor mortar. After immersing the mixed powder, the mixture was heated with stirring to evaporate the moisture, further dried by ventilation at 110 ° C., and then calcined in air at 500 ° C. for 3 hours in the same manner as in the case of Catalyst 1 above. Comparative catalyst C9 was obtained. The catalyst C9 of this comparative example does not contain cerium oxide, the manganese oxide content is 10% by weight in terms of MnO 2 , and the alumina content is 30% by weight of the total catalyst.
上記触媒１と同様にアンモニア分解触媒を調製する際に、モルデナイト粉末を加えず、且つアルミナの含有量を触媒全体の８０重量％とした以外は上記触媒１の場合と同様にして、比較例の触媒Ｃ１０を得た。尚、この比較例の触媒Ｃ１０は、ゼオライトを含まず、酸化マンガンの含有量がＭｎＯ２換算で触媒全体の１０重量％、酸化セリウムの含有量がＣｅＯ２換算で触媒全体の１０重量％である。上記した本発明の触媒１〜１６及び比較例の触媒Ｃ１〜Ｃ１０の各組成を下記表１にまとめて示した。 When preparing an ammonia decomposition catalyst in the same manner as in the above catalyst 1, a mordenite powder was not added, and the content of alumina was set to 80% by weight of the total catalyst. Catalyst C10 was obtained. In addition, the catalyst C10 of this comparative example does not contain zeolite, the manganese oxide content is 10% by weight of the whole catalyst in terms of MnO 2 , and the cerium oxide content is 10% by weight of the whole catalyst in terms of CeO 2. . The compositions of the catalysts 1 to 16 of the present invention and the catalysts C1 to C10 of the comparative examples are summarized in Table 1 below.
［触媒の評価試験］
上記した本発明の触媒１〜１６及び比較例の触媒Ｃ１〜Ｃ１０について、アンモニア分解能を評価した。即ち、各触媒をそれぞれ内径６ｍｍの石英ガラス製反応管に充填して触媒体を形成し、これを常圧固定床流通反応装置に装着した。この反応管内に、モデル排ガスとしてＮＨ３：５,０００ｐｐｍ、Ｏ２：１７％、Ｈ２Ｏ：１２％、残部：Ｎ２からなる混合ガスを、ガス温度３００℃、空間速度５０,０００／ｈで通過させ、アンモニアの分解処理を行った。得られた結果を、各触媒の構成と共に下記表２に示す。
[Catalyst evaluation test]
The ammonia decomposability was evaluated for the catalysts 1 to 16 of the present invention and the catalysts C1 to C10 of the comparative examples. That is, each catalyst was filled in a quartz glass reaction tube having an inner diameter of 6 mm to form a catalyst body, which was attached to an atmospheric pressure fixed bed flow reactor. In this reaction tube, as a model exhaust gas, a mixed gas composed of NH 3 : 5,000 ppm, O 2 : 17%, H 2 O: 12%, and the balance: N 2 was supplied at a gas temperature of 300 ° C. and a space velocity of 50,000 / h. Then, ammonia was decomposed. The obtained results are shown in Table 2 below together with the structure of each catalyst.
尚、アンモニア分解率は下記数式１、ＮＯｘ生成率は下記数式２、及びＮ２Ｏ生成率は下記数式３に従って算出した。
［数式１］
アンモニア分解率(％)＝(入口ＮＨ３濃度−出口ＮＨ３濃度)／入口ＮＨ３濃度×１００
［数式２］
ＮＯｘ生成率(％)＝(出口ＮＯ濃度＋出口ＮＯ２濃度)／入口ＮＨ３濃度×１００
［数式３］
Ｎ２Ｏ生成率(％)＝出口Ｎ２Ｏ濃度×２／入口ＮＨ３濃度×１００
The ammonia decomposition rate was calculated according to the following formula 1, the NOx generation rate was calculated according to the following formula 2, and the N 2 O generation rate was calculated according to the following formula 3.
[Formula 1]
Ammonia decomposition rate (%) = (Inlet NH 3 concentration−Outlet NH 3 concentration) / Inlet NH 3 concentration × 100
[Formula 2]
NOx generation rate (%) = (outlet NO concentration + outlet NO 2 concentration) / inlet NH 3 concentration × 100
[Formula 3]
N 2 O production rate (%) = Outlet N 2 O concentration × 2 / Inlet NH 3 concentration × 100
上記表１及び表２から分かるように、酸化マンガンと酸化セリウムとアルミナとゼオライトを含有した本発明のアンモニア分解触媒では、酸化マンガンがＭｎＯ２換算で１〜６０重量％、酸化セリウムがＣｅＯ２換算で１〜３０重量％、及びアルミナが１０〜７０重量％であるとき、９０％を超えるアンモニア分解率で排ガス中のアンモニアを窒素に分解することができ、しかも、高温条件下や酸素過剰条件下であっても、大気汚染物質である窒素酸化物ＮＯｘやＮ２Ｏの副生を抑制することができた。 As can be seen from Table 1 and Table 2 above, in the ammonia decomposition catalyst of the present invention containing manganese oxide, cerium oxide, alumina and zeolite, manganese oxide is 1 to 60% by weight in terms of MnO 2 and cerium oxide is in terms of CeO 2. 1 to 30% by weight, and alumina is 10 to 70% by weight, ammonia in exhaust gas can be decomposed into nitrogen at an ammonia decomposition rate exceeding 90%. Even so, by-products of nitrogen oxides NOx and N 2 O, which are air pollutants, could be suppressed.
一方、比較例の触媒Ｃ１、Ｃ５、Ｃ８は、酸化マンガンを含まないか又はその含有量が１重量％未満であるため、アンモニア分解率が著しく低下した。また、比較例の触媒Ｃ２は、逆に酸化マンガンの含有量が６０重量％を超えるため、アンモニア分解率は高いが、ＮＯｘやＮ２Ｏの副生が極めて多くなった。 On the other hand, the catalysts C1, C5, and C8 of Comparative Examples did not contain manganese oxide or contained less than 1% by weight, so the ammonia decomposition rate was significantly reduced. In contrast, the catalyst C2 of the comparative example, on the contrary, has a manganese oxide content exceeding 60% by weight, and thus the ammonia decomposition rate is high, but NOx and N 2 O by-products are extremely increased.
比較例の触媒Ｃ３、Ｃ９は、酸化セリウムを含まないか又はその含有量が１重量％未満であるため、アンモニア分解率が著しく低下した。また、比較例の触媒Ｃ４、Ｃ６、Ｃ７は、逆に酸化セリウムの含有量が３０重量％を超えているため、アンモニア分解率は高いが、ＮＯｘやＮ２Ｏの副生が大幅に増加した。更に、比較例の触媒Ｃ１０は、アルミナの含有量が７０重量％を超え且つゼオライトが含有されていないため、アンモニア分解率は高いが、ＮＯｘやＮ２Ｏの副生が大幅に増加した。
Since the catalysts C3 and C9 of Comparative Examples did not contain cerium oxide or contained less than 1% by weight, the ammonia decomposition rate was remarkably reduced. In contrast, the catalysts C4, C6, and C7 of Comparative Examples had a high ammonia decomposition rate because the content of cerium oxide exceeded 30% by weight, but NOx and N 2 O by-products were greatly increased. . Furthermore, the catalyst C10 of Comparative Example has a high ammonia decomposition rate because the alumina content exceeds 70% by weight and no zeolite is contained, but NOx and N 2 O by-products are greatly increased.
Claims (3)
An ammonia treatment method for removing ammonia in exhaust gas by oxidative decomposition using a catalyst, wherein the ammonia decomposition catalyst according to claim 1 or 2 is used.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006144769A JP2007313410A (en) | 2006-05-25 | 2006-05-25 | Ammonia decomposition catalyst and ammonia treating method |
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| JP2006144769A JP2007313410A (en) | 2006-05-25 | 2006-05-25 | Ammonia decomposition catalyst and ammonia treating method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010107065A1 (en) * | 2009-03-17 | 2010-09-23 | 株式会社日本触媒 | Catalyst for production of hydrogen and process for producing hydrogen using the catalyst, and catalyst for combustion of ammonia, process for producing the catalyst, and method for combustion of ammonia using the catalyst |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010107065A1 (en) * | 2009-03-17 | 2010-09-23 | 株式会社日本触媒 | Catalyst for production of hydrogen and process for producing hydrogen using the catalyst, and catalyst for combustion of ammonia, process for producing the catalyst, and method for combustion of ammonia using the catalyst |
| US8962518B2 (en) | 2009-03-17 | 2015-02-24 | Nippon Shokubai Co., Ltd. | Catalyst for production of hydrogen and process for producing hydrogen using the catalyst, and catalyst for combustion of ammonia, process for producing the catalyst and process for combusting ammonia using the catalyst |
| US10857523B2 (en) | 2009-03-17 | 2020-12-08 | Nippon Shokubai Co., Ltd. | Catalyst for production of hydrogen and process for producing hydrogen using the catalyst, and catalyst for combustion of ammonia, process for producing the catalyst and process for combusting ammonia using the catalyst |
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