JPH06126134A - Method for purification of nitrogen oxide in exhaust gas - Google Patents
Method for purification of nitrogen oxide in exhaust gasInfo
- Publication number
- JPH06126134A JPH06126134A JP4300381A JP30038192A JPH06126134A JP H06126134 A JPH06126134 A JP H06126134A JP 4300381 A JP4300381 A JP 4300381A JP 30038192 A JP30038192 A JP 30038192A JP H06126134 A JPH06126134 A JP H06126134A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- silica
- alumina
- hydrocarbons
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、排ガス中の窒素酸化物
浄化方法に関する。より詳しくは、選択還元触媒を用い
た排ガス中の窒素酸化物の浄化方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying nitrogen oxides in exhaust gas. More specifically, it relates to a method for purifying nitrogen oxides in exhaust gas using a selective reduction catalyst.
【０００２】[0002]
【従来の技術】近年、都市部の窒素酸化物（ＮＯｘ）濃
度が一向に減少しないことを反映して、都市部の固定発
生源からのＮＯｘの排出をより低減しようとする要求が
急速に高まってきている。それらの固定発生源の中に
は、燃焼法の改善によりＮＯｘの生成量を低減できるも
のもあるが、エンジンなど、本質的に高い濃度のＮＯｘ
を排出するものも多い。従って、排ガス中のＮＯｘを浄
化する技術が望まれているが、通常の燃焼排ガスには、
酸素が大量に含まれており、そのような雰囲気下でＮＯ
ｘを浄化できる技術としては、火力発電所等で用いられ
ているアンモニア脱硝法がある。これは、アンモニアが
酸素の存在下、ＮＯｘと選択的に反応することを利用し
たもので、Ｖ2Ｏ5／ＴｉＯ2系等の触媒を用い、アンモ
ニアをＮＯｘとほぼ当モルになるように制御して注入す
る。2. Description of the Related Art In recent years, reflecting the fact that the concentration of nitrogen oxides (NOx) in urban areas does not decrease at all, the demand for further reduction of NOx emissions from fixed sources in urban areas has increased rapidly. ing. Some of these fixed sources can reduce the amount of NOx produced by improving the combustion method.
Many also emit. Therefore, there is a demand for a technique for purifying NOx in exhaust gas.
It contains a large amount of oxygen and NO in such an atmosphere.
As a technique for purifying x, there is an ammonia denitration method used in thermal power plants and the like. This utilizes the fact that ammonia selectively reacts with NOx in the presence of oxygen. Using a catalyst such as a V 2 O 5 / TiO 2 system, ammonia is controlled to be almost equimolar to NOx. Then inject.
【０００３】[0003]
【発明が解決しようとする課題】しかし、アンモニア脱
硝法では、脱硝率を向上させるためにアンモニアを過剰
に添加すると、未反応のアンモニアがスリップし、かえ
って有毒ガスを排出してしまう結果となるため、実用上
は脱硝率には限界がある。また、ＮＯｘ計を用いてＮＯ
ｘ濃度を常にモニターし、アンモニア注入量を厳密に制
御する高価なシステムが必要であり、さらに有毒のアン
モニアガスをハンドリングするために様々な付帯設備が
必要で装置が大がかりになり、都市部の小型燃焼器のＮ
Ｏｘ低減には事実上適用できないという問題がある。However, in the ammonia denitration method, if ammonia is excessively added in order to improve the denitration rate, unreacted ammonia slips, which results in the emission of toxic gas. However, the denitration rate is practically limited. In addition, NO using a NOx meter
An expensive system that constantly monitors x concentration and strictly controls the amount of ammonia injection is required. Furthermore, various incidental equipment is required to handle toxic ammonia gas, and the equipment becomes large, making it a small city area. Combustor N
There is a problem that it is practically not applicable to Ox reduction.
【０００４】[0004]
【課題を解決するための手段】本発明者は、上記の如き
問題点に鑑みて、鋭意研究を重ねた結果、ゾルゲル法に
より得られたシリカアルミナ担体に特定の遷移金属を担
持した触媒を用い、炭化水素によりＮＯｘを選択的に還
元できることを見出して完成させたもので、本発明は、
炭化水素及び酸素の存在する排ガスをＣｕ、Ｃｏ、Ｍ
ｎ、Ｆｅ、Ｎｉ、Ｚｎ及びＡｇから選ばれた少なくとも
１種類の金属を含有する、ゾルゲル法により得られたシ
リカアルミナ系選択還元触媒を用いて、排ガス中の窒素
酸化物を炭化水素により選択的に還元浄化することを特
徴とする。Means for Solving the Problems The present inventors have conducted extensive studies in view of the above problems, and as a result, have found that a silica-alumina carrier obtained by the sol-gel method uses a catalyst having a specific transition metal supported thereon. The present invention was completed by discovering that NOx can be selectively reduced by hydrocarbons.
Exhaust gas in the presence of hydrocarbons and oxygen is Cu, Co, M
Using a silica-alumina-based selective reduction catalyst obtained by the sol-gel method, containing at least one metal selected from n, Fe, Ni, Zn and Ag, nitrogen oxides in exhaust gas are selectively removed by hydrocarbons. It is characterized by reducing and purifying.
【０００５】本発明では、ＮＯｘを酸素の存在下、炭化
水素で選択的に還元するための触媒（選択還元触媒）と
して、金属担持シリカアルミナ触媒を用いる。触媒の細
孔径としては３０〜５０オングストローム程度がよく、
酸強度としてはＨ0＝−５〜−１０がよく、これらの物
性を有するシリカアルミナは、以下に示すゾルゲル法に
より容易に調製することができる。In the present invention, a metal-supported silica-alumina catalyst is used as a catalyst (selective reduction catalyst) for selectively reducing NOx with hydrocarbons in the presence of oxygen. The pore size of the catalyst is preferably about 30 to 50 Å,
The acid strength is preferably H 0 = −5 to −10, and silica-alumina having these physical properties can be easily prepared by the sol-gel method shown below.
【０００６】ゾルゲル法によるシリカガラスの製造法
は、金属アルコキシドのアルコール溶液に、一定量の水
と鉱酸、有機酸、無機塩基、アンモニアなどの触媒を加
えて合成されるウェットゲルを乾燥加熱してドライゲル
としたものを、さらに１０００℃程度で熱処理し透明な
ガラスとしている。従来よりゾルゲル法により短時間で
品質の優れたガラスを製造するためにいくつかの試みが
なされ報告されている（特開昭６０−２７６１１号、特
開昭６０−２１５５３２号、特開昭５７−７８１４号な
ど参照）。発明者等は、Ｓｉ系及びＡｌ系の金属アルコ
キシドを混合しゾルゲル法によって合成することにより
シリカアルミナゲルを作製し検討を重ねた結果、ゾルゲ
ル法によって得られたドライゲルは均一な組成をもち、
また適度な細孔分布と酸強度分布を持っており、本ドラ
イゲルを担体として利用できることを見出した。ゾルゲ
ル法により合成されたシリカアルミナの特長としては、
担体の均質性が良好であること、またシリカ（Ｓｉ）−
アルミ（Ａｌ）比（Ｓｉ／Ａｌ）を金属アルコキシドの
添加比により任意にコントロールできること、また金属
アルコキシドの溶媒（アルコール）及び合成触媒、乾燥
加熱条件を変化させることにより細孔径及び細孔分布を
変化させることが可能であるなどの種々の特長がある。
それゆえ、ゾルゲル法は最適な触媒を合成する優れた方
法である。また本シリカアルミナに遷移金属を担持する
場合もゾルゲル法の特長を利用して均質に担持が可能で
ある。またハニカム構造物に触媒をコーティングする場
合も金属アルコキシド溶液の状態でコーティングするこ
とが可能である。The method of producing silica glass by the sol-gel method is to dry and heat a wet gel synthesized by adding a certain amount of water and a catalyst such as a mineral acid, an organic acid, an inorganic base or ammonia to an alcohol solution of a metal alkoxide. The dried gel is further heat treated at about 1000 ° C. to obtain transparent glass. Heretofore, several attempts have been made and reported to produce a glass of excellent quality in a short time by the sol-gel method (JP-A-60-27611, JP-A-60-215532, JP-A-57-57). 7814, etc.). The inventors have made a silica alumina gel by mixing the Si-based and Al-based metal alkoxides and synthesizing them by the sol-gel method, and as a result of repeated studies, the dry gel obtained by the sol-gel method has a uniform composition,
It was also found that the present dry gel can be used as a carrier because it has an appropriate pore distribution and acid strength distribution. The features of silica-alumina synthesized by the sol-gel method are:
Good homogeneity of the carrier and silica (Si)-
The aluminum (Al) ratio (Si / Al) can be arbitrarily controlled by the addition ratio of the metal alkoxide, and the pore size and pore distribution can be changed by changing the solvent (alcohol) of the metal alkoxide, the synthetic catalyst, and the drying and heating conditions. There are various features such as being possible.
Therefore, the sol-gel method is an excellent method for synthesizing an optimal catalyst. Also, when the transition metal is supported on the silica-alumina, it can be supported uniformly by utilizing the features of the sol-gel method. When the honeycomb structure is coated with the catalyst, it can be coated in the state of the metal alkoxide solution.
【０００７】上記のゾルゲル法は常法に準じて行うこと
ができる。ゾルゲル法に用いる触媒としても既知の様々
な触媒を用いることが可能であるが、発明者等は従来よ
り鋭意検討を重ねた結果、鉱酸（例えば、塩酸、硫酸、
硝酸等）又はその無水物と有機塩基とを含み、当該有機
塩基が水に実質的に不溶であり且つ有機溶媒に可溶な第
三アミン（例えば、Ｎ，Ｎ−ジメチルベンジルアミン、
トリブチルアミン、トリペンチルアミン等）を用いるこ
とを提案している（特開昭６３−２２９１４６号参
照）。より具体的には、例えば、アルミニウムのアルコ
キシド（例えば、Ａｌ［ＯＣＨ（ＣＨ3）2］3等）の酸
加水分解物含水アルコール溶液と、ケイ素のアルコキシ
ド（例えば、Ｓｉ（ＯＣ2Ｈ5）4等）の酸加水分解物含
水アルコール溶液とを所望の比率で混合した後、上記の
水不溶性第三アミンを添加し、重縮合させることにより
ウェットゲルが得られる。得られたウェットゲルを、常
法に準じて、乾燥、熱処理し、シリカアルミナ担体が得
られる。この方法で合成したシリカアルミナ担体は、本
発明の選択還元触媒の前駆体としても非常に有用である
ことを見出した。The sol-gel method described above can be carried out according to a conventional method. Although it is possible to use various known catalysts as the catalyst used in the sol-gel method, the present inventors have conducted extensive studies as a result, and as a result, mineral acids (for example, hydrochloric acid, sulfuric acid,
Nitric acid or the like) or an anhydride thereof and an organic base, the organic base being substantially insoluble in water and soluble in an organic solvent (for example, N, N-dimethylbenzylamine,
The use of tributylamine, tripentylamine, etc.) has been proposed (see JP-A-63-229146). More specifically, for example, an acid hydrolyzate-containing alcohol solution of an aluminum alkoxide (for example, Al [OCH (CH 3 ) 2 ] 3 ) and a silicon alkoxide (for example, Si (OC 2 H 5 ) 4 Etc.) and the acid hydrolyzate containing hydroalcoholic solution at a desired ratio, and then the above water-insoluble tertiary amine is added and polycondensed to obtain a wet gel. The obtained wet gel is dried and heat treated according to a conventional method to obtain a silica-alumina carrier. It was found that the silica-alumina carrier synthesized by this method is also very useful as a precursor of the selective reduction catalyst of the present invention.
【０００８】一方、従来、ガソリンエンジン排ガス中の
ＮＯｘの浄化方法として、ゼオライトなどを触媒として
用いると共に排ガス中に含まれる高級炭化水素によりＮ
Ｏｘを還元する選択還元方法が知られている。しかし、
炭化水素によるＮＯｘ選択還元反応は、共存している水
分により阻害を受ける。従来、水分による反応阻害のメ
カニズムについてはまったく知られていなかったが、本
発明者等は、 なる２段階の反応を仮定すると、水は１段目の炭化水素
の部分酸化ないし分解反応を著しく阻害しており、２段
目の選択還元反応の選択性［ＣxＨy（Ｏ）のＯ2による
酸化反応に対するＮＯｘによる反応の割合］にはあまり
影響しないことを見出した。さらに、炭化水素の酸化活
性の高い触媒を用いて、適当な温度領域で、炭化水素を
共存させることにより、水分による反応阻害の影響を低
減でき、排ガス中のＮＯｘを選択的に還元できることを
見出した。即ち、本発明においては、シリカアルミナ
に、酸化活性を与えるために遷移金属を担持した触媒を
用いる。遷移金属の中でも白金族のような酸化活性の高
すぎる触媒の場合は、選択還元反応の選択性が低下する
ので、遷移金属として、Ｃｕ、Ｃｏ、Ｍｎ、Ｆｅ、Ｎ
ｉ、Ｚｎ及びＡｇの中から選ばれたものを少なくとも１
つ以上含むことが好ましい。金属の含有量は、排ガス組
成などにより大きく異なるが、金属として０．１重量％
から２０％の間が好ましい。これより少ないと十分な酸
化活性を得られず、これより多いと金属の表面積の低下
を招き、また、本来触媒のもつＮＯｘの選択還元反応活
性を低下させてしまう。より好ましくは、シリカアルミ
ナの上にＣｏ又はＣｕを少なくとも担持した触媒が用い
られ、特に、シリカアルミナ重量に対して０．５〜５重
量％程度、好ましくは１〜３重量％程度の金属を担持し
てものが好適に使用される。かかる触媒は、圧損を低減
するため、ハニカム状で使われるが、触媒自体をハニカ
ム状に成型してもよいが、強度が足りないものでは、コ
ージェライト等のハニカム構造物に触媒をウォシュコー
トしてもよい。また、金属は、最初からアルコキシドと
して含ませていてもよく、粉体のシリカアルミナに含浸
担持してもよく、またハニカム成型後に含浸させてもよ
い。On the other hand, conventionally, as a method of purifying NOx in the exhaust gas of a gasoline engine, zeolite or the like is used as a catalyst, and N contained by the higher hydrocarbons contained in the exhaust gas.
A selective reduction method for reducing Ox is known. But,
The NOx selective reduction reaction by hydrocarbons is hindered by coexisting water. Conventionally, the mechanism of reaction inhibition by water was not known at all, but the present inventors have Assuming the following two-step reaction, water significantly inhibits the partial oxidation or decomposition reaction of the first-stage hydrocarbon, and the selectivity of the second-stage selective reduction reaction [C x H y (O) O The ratio of the reaction by NOx with respect to the oxidation reaction by 2 ] was not so affected. Furthermore, it was found that the influence of water on the reaction inhibition can be reduced and the NOx in the exhaust gas can be selectively reduced by allowing the hydrocarbon to coexist in an appropriate temperature range using a catalyst with a high hydrocarbon oxidation activity. It was That is, in the present invention, a catalyst in which a transition metal is supported in order to give oxidation activity to silica alumina is used. In the case of a catalyst having an excessively high oxidation activity such as platinum group among the transition metals, the selectivity of the selective reduction reaction decreases, and therefore Cu, Co, Mn, Fe, N are used as the transition metals.
At least 1 selected from i, Zn, and Ag
It is preferable to include one or more. The content of metal varies greatly depending on the exhaust gas composition, etc., but is 0.1% by weight as metal.
Between 20% and 20% is preferred. If it is less than this, sufficient oxidation activity cannot be obtained, and if it is more than this, the surface area of the metal is reduced, and the NOx selective reduction reaction activity originally possessed by the catalyst is reduced. More preferably, a catalyst in which at least Co or Cu is supported on silica alumina is used, and particularly, about 0.5 to 5% by weight, preferably about 1 to 3% by weight of metal is supported on the weight of silica alumina. Mostly used. Such a catalyst is used in a honeycomb shape to reduce pressure loss, but the catalyst itself may be molded into a honeycomb shape, but if the strength is insufficient, a honeycomb structure such as cordierite is wash-coated with the catalyst. May be. The metal may be contained as an alkoxide from the beginning, may be impregnated and supported on powdered silica-alumina, or may be impregnated after honeycomb molding.
【０００９】かくして得られた触媒体は、ＮＯｘを含有
し且つ炭化水素及び酸素の存在する種々の排ガスの浄化
に使用することができ、特に、天然ガスを空燃比１以上
で燃焼した、酸素と炭化水素の存在する排ガス中の窒素
酸化物の浄化に好適に用いられる。天然ガスの燃焼排ガ
スのように、排ガス中に存在する炭化水素がメタンなど
の選択性の低い炭化水素だけであったり、その量が少な
いときは、外部から炭化水素を添加してもよい。この時
用いられる炭化水素としては、プロパンガス、ブタンガ
ス、プロピレンガス、液化石油ガスナフサ、ガソリン、
灯油などが挙げられ、特に限定されるものではないが、
硫黄を著しく多く含む軽油などは、触媒金属を被毒し、
活性及び寿命を低下させるので避けるべきであり、従っ
て、硫黄として１００ｐｐｍ以下に脱硫された炭化水素
を用いる。この時、炭素数２以下のパラフィンでは、酸
化・分解反応が起こりにくいため、水分の反応阻害によ
り酸化反応が進まず、添加しても効果は少ないので、炭
素数３以上のパラフィン及び／又は炭素数２以上のオレ
フィンが好ましい。また、炭化水素の量は、ＮＯｘの濃
度、酸素濃度により異なるが、炭化水素の排ガス中の濃
度がＮＯｘ濃度に対して、ＴＨＣ（メタン換算）とし
て、当量から当量の５０倍の間となるように調整する。
好ましくは、炭素数６以下の炭化水素の場合、該当量の
５倍から２５倍、炭素数６を越える炭化水素の場合は、
当量の２倍から１０倍程度となるようにする。炭化水素
濃度を高くすればするほど脱硝率はよくなるが、同じＴ
ＨＣ濃度でも高級な炭化水素ほど選択性が高く効果的に
働くため、少ない炭化水素でＮＯｘ還元ができるが、逆
に多く加えると炭化水素がスリップしてしまい、好まし
くない。The thus obtained catalyst body can be used for purification of various exhaust gases containing NOx and in which hydrocarbons and oxygen are present. In particular, natural gas is burned at an air-fuel ratio of 1 or more to obtain oxygen. It is preferably used for purification of nitrogen oxides in exhaust gas containing hydrocarbons. As in the case of combustion exhaust gas of natural gas, the hydrocarbons present in the exhaust gas are only hydrocarbons with low selectivity such as methane, or when the amount is small, hydrocarbons may be added from the outside. The hydrocarbons used at this time are propane gas, butane gas, propylene gas, liquefied petroleum gas naphtha, gasoline,
Examples include kerosene, which is not particularly limited,
Diesel oil containing a large amount of sulfur poisons catalytic metals,
It should be avoided as it reduces activity and life, and therefore hydrocarbons desulfurized to 100 ppm or less are used as sulfur. At this time, with paraffins having 2 or less carbon atoms, the oxidation / decomposition reaction is unlikely to occur, so the oxidation reaction does not proceed due to the inhibition of water reaction, and even if added, the effect is small. Olefins having a number of 2 or more are preferred. The amount of hydrocarbons varies depending on the concentration of NOx and the concentration of oxygen, but the concentration of hydrocarbons in the exhaust gas should be between equivalent and 50 times the equivalent as THC (methane conversion) with respect to the NOx concentration. Adjust to.
Preferably, in the case of a hydrocarbon having 6 or less carbon atoms, 5 to 25 times the corresponding amount, and in the case of a hydrocarbon having more than 6 carbon atoms,
Make it about 2 to 10 times the equivalent weight. The higher the hydrocarbon concentration, the better the denitration rate, but the same T
Higher-grade hydrocarbons have higher selectivity even when the concentration of HC is high and work effectively, so that NOx can be reduced with a small amount of hydrocarbons, but if a large amount is added, the hydrocarbons will slip, which is not preferable.
【００１０】本発明では、選択還元触媒は、３５０℃〜
６００℃、好ましくは４００℃〜５００℃で使用され
る。これより温度が低いと炭化水素の酸化・分解が進ま
ず、また、温度が高いとＮＯｘ還元反応の選択性が低下
し、炭化水素の必要量が増加する。また、ＧＨＳＶ(Gas
eous hourly space velocity)は５０００〜１００００
０の範囲で使用され、好ましくは１００００〜３０００
０の範囲で使用される。ＧＨＳＶが大きくなりすぎると
炭化水素が未反応ままスリップし、小さすぎると触媒容
器が大きくなりすぎ、圧損が増大して燃焼器自体の特性
を損なう恐れがあり、好ましくない。本発明で開示され
る好ましい条件で排ガス中の窒素酸化物を浄化する場合
には、未反応の炭化水素や炭化水素や部分酸化物が触媒
出口で大量にスリップすることはなく、後流側に酸化触
媒をおいて酸化する必要はないが、排ガス中に未燃メタ
ンがもともと含まれる場合や、好ましい条件で実施でき
ない場合、後流側に酸化触媒を配してメタンや未反応炭
化水素等を触媒燃焼させてもよい。酸化触媒としては、
従来から用いられている卑金属酸化物系触媒、金属担持
触媒などの各種酸化触媒を用いることができるが、活性
の高い、Ｐｔ、Ｒｈ、Ｐｄ、Ｒｕなどを活性アルミナな
どに担持した貴金属系触媒が好ましい。In the present invention, the selective reduction catalyst has a temperature of 350.degree.
It is used at 600 ° C, preferably 400 ° C to 500 ° C. If the temperature is lower than this, the oxidation / decomposition of hydrocarbons will not proceed, and if the temperature is higher, the selectivity of the NOx reduction reaction will decrease and the required amount of hydrocarbons will increase. In addition, GHSV (Gas
eous hourly space velocity) is 5000-10000
Used in the range of 0, preferably 10,000 to 3000
Used in the 0 range. If the GHSV becomes too large, the hydrocarbons will slip unreacted, and if it is too small, the catalyst container will become too large and the pressure loss will increase, possibly impairing the characteristics of the combustor itself, which is not preferable. When purifying the nitrogen oxides in the exhaust gas under the preferred conditions disclosed in the present invention, unreacted hydrocarbons and hydrocarbons and partial oxides do not slip in large amounts at the catalyst outlet, and do not slip to the downstream side. It is not necessary to oxidize with an oxidation catalyst, but if unburned methane is originally contained in the exhaust gas or if it cannot be carried out under favorable conditions, an oxidation catalyst is placed on the downstream side to remove methane and unreacted hydrocarbons. It may be catalytically burned. As an oxidation catalyst,
Various oxidation catalysts such as base metal oxide-based catalysts and metal-supported catalysts that have been conventionally used can be used, but noble metal-based catalysts having highly active Pt, Rh, Pd, Ru, etc. supported on activated alumina are used. preferable.
【００１１】[0011]
【実施例】以下、実施例に基づいて本発明を詳細に説明
するが、本発明はこれらの実施例に限定されるものでは
ない。 実施例１ （触媒調製法）アルミニウムイソプロポキシド（Ａｌ
［ＯＣＨ（ＣＨ3）2］3）４３．１５ｇを濃塩酸４３．
１５ｇに溶解した後、エタノール４３１ｇ、水２１６ｇ
を加え６０〜７０℃にて約１０分撹拌し、溶液Ａとし
た。エチルシリケート（Ｓｉ（ＯＣ2Ｈ5）4）５００ｇ
にメタノール６３０ｍｌを加え混合した後、０．８３Ｎ
の塩酸１１６ｇを加え１０分間放置した後、溶液Ａを３
２５ｍｌ加え撹拌した後、２０日間放置し、ゲル化を生
じさせた。ゲル化したシリカアルミナを１３０℃、１７
時間減圧乾燥した後、窒素ガス雰囲気中４５０℃で３時
間焼成しＳｉ／Ａｌ＝２８、比表面積４０２（ｍ2／
ｇ）のシリカアルミナを得た。該シリカアルミナを０．
１Ｍ硝酸銅水溶液に浸漬させ、含浸法により銅を担持
し、粉砕して１〜２ｍｍの細粒とした後、５００℃で１
５時間焼成して選択還元触媒（Ｃｕ含有量１．８重量
％）を得た。 （脱硝試験）上記で得られた触媒を４ｃｃ充填し、５０
０℃で、天然ガスを内燃機関で空燃比２で燃焼したとき
に相当する表１に示す組成（容量ベース）の模擬排ガス
に、Ｃ3Ｈ8を１０００ｐｐｍとなるように加えたガスを
１リットル／ｍｉｎ（ＧＨＳＶ＝１５０００）流通さ
せ、触媒出口のＮＯｘ濃度をＮＯｘコンバーター付の化
学発光式のＮＯｘ計で測定したところ、８０ｐｐｍであ
った。EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. Example 1 (Catalyst preparation method) Aluminum isopropoxide (Al
43.15 g of [OCH (CH 3 ) 2 ] 3 ) was added to concentrated hydrochloric acid 43.
After dissolving in 15g, ethanol 431g, water 216g
Was added and stirred at 60 to 70 ° C. for about 10 minutes to prepare a solution A. Ethyl silicate (Si (OC 2 H 5 ) 4 ) 500 g
After adding 630 ml of methanol to the mixture and mixing, 0.83N
116 g of hydrochloric acid was added and left for 10 minutes.
After adding 25 ml and stirring, the mixture was left for 20 days to cause gelation. Gelled silica-alumina at 130 ℃, 17
After drying under reduced pressure for 3 hours, it is baked at 450 ° C. for 3 hours in a nitrogen gas atmosphere, Si / Al = 28, and a specific surface area of 402 (m 2 /
g) Silica-alumina was obtained. The silica-alumina was
After immersing in a 1M copper nitrate aqueous solution, supporting copper by an impregnation method, and pulverizing it into fine particles of 1 to 2 mm, it is 1 at 500 ° C.
It was calcined for 5 hours to obtain a selective reduction catalyst (Cu content 1.8% by weight). (Denitration test) 4 cc of the catalyst obtained above was filled, and 50
At 0 ° C., 1 liter of gas obtained by adding C 3 H 8 to 1000 ppm to simulated exhaust gas having the composition (volume basis) shown in Table 1 corresponding to the case of burning natural gas with an internal combustion engine at an air-fuel ratio of 2 / Min (GHSV = 15000), and the NOx concentration at the catalyst outlet was measured by a chemiluminescence type NOx meter equipped with a NOx converter and found to be 80 ppm.
【００１２】 [0012]
【００１３】実施例２ （触媒調製法）アルミニウムイソプロポキシド（Ａｌ
［ＯＣＨ（ＣＨ3）2］3）４３．１５ｇを濃塩酸４３．
１５ｇに溶解した後、エタノール４３１ｇ、水２１６ｇ
を加え６０〜７０℃にて約１０分撹拌し溶液Ａとした。
エチルシリケート（Ｓｉ（ＯＣ2Ｈ5）4）５００ｇにメ
タノール６３０ｍｌを加え混合した後、０．８３Ｎの塩
酸１１６ｇを加え１０分間放置した後、溶液Ａを６５０
ｍｌ加え撹拌した後、１．２５モルのＮ，Ｎ−ジメチル
ベンジルアミンのエタノール溶液を加え数分でゲル化を
生じさせた。ゲル化したシリカアルミナを１３０℃、１
７時間減圧乾燥した後、窒素ガス雰囲気中４５０℃で３
時間焼成しＳｉ／Ａｌ＝１４、比表面積４００（ｍ2／
ｇ）のシリカアルミナを得た。該シリカアルミナを０．
１Ｍ硝酸銅水溶液に浸漬させ、含浸法により銅を担持
し、粉砕して１〜２ｍｍの細粒とした後、５００℃で１
５時間焼成して選択還元触媒（Ｃｕ含有量２．２重量
％）を得た。 （脱硝試験）上記で得られた触媒を用いる以外は、実施
例１と同様にして活性試験を行ったところ、触媒出口の
ＮＯｘ濃度は、８５ｐｐｍであった。Example 2 (Catalyst preparation method) Aluminum isopropoxide (Al
43.15 g of [OCH (CH 3 ) 2 ] 3 ) was added to concentrated hydrochloric acid 43.
After dissolving in 15g, ethanol 431g, water 216g
Was added and stirred at 60 to 70 ° C. for about 10 minutes to prepare a solution A.
After adding 630 ml of methanol to 500 g of ethyl silicate (Si (OC 2 H 5 ) 4 ) and mixing, 116 g of 0.83N hydrochloric acid was added and left for 10 minutes, and then solution A of 650
After adding ml and stirring, 1.25 mol of N, N-dimethylbenzylamine in ethanol was added to cause gelation in several minutes. Gelled silica-alumina at 130 ℃, 1
After drying under reduced pressure for 7 hours, at 450 ° C in a nitrogen gas atmosphere for 3 hours.
Sintered for hours, Si / Al = 14, specific surface area 400 (m 2 /
g) Silica-alumina was obtained. The silica-alumina was
After immersing in a 1M copper nitrate aqueous solution, supporting copper by an impregnation method, and pulverizing it into fine particles of 1 to 2 mm, it is 1 at 500 ° C.
It was calcined for 5 hours to obtain a selective reduction catalyst (Cu content 2.2% by weight). (Denitration test) When an activity test was conducted in the same manner as in Example 1 except that the catalyst obtained above was used, the NOx concentration at the catalyst outlet was 85 ppm.
【００１４】[0014]
【発明の効果】本発明にかかる炭化水素によるＮＯｘの
選択還元浄化法では、アンモニアを使用することなく、
炭化水素により効果的にＮＯｘを選択的に還元できるた
め、アンモニアのスリップを防ぐためのアンモニア注入
量の制御系や、アンモニアをハンドリングするために必
要な設備が不要となり、触媒量も少なくなり、システム
が簡略化され、小型の燃焼器にも経済的に適用できる。INDUSTRIAL APPLICABILITY In the selective reduction purification method of NOx by hydrocarbon according to the present invention, without using ammonia,
Since NOx can be selectively reduced effectively with hydrocarbons, a system for controlling the amount of injected ammonia to prevent slipping of ammonia and equipment necessary for handling ammonia are not required, and the amount of catalyst is reduced, resulting in a system. Is simplified and can be economically applied to a small combustor.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０１Ｊ 23/74 Ａ 8017−4Ｇ (72)発明者 北出 勝美 大阪市中央区平野町四丁目１番２号 大阪 瓦斯株式会社内 (72)発明者 青▲柳▼ 祐介 大阪市中央区平野町四丁目１番２号 大阪 瓦斯株式会社内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Internal reference number FI Technical indication location B01J 23/74 A 8017-4G (72) Inventor Katsumi Kitade 4-chome, Hirano-cho, Chuo-ku, Osaka No. 2 in Osaka Gas Co., Ltd. (72) Inventor Ao Yanagi Yusuke 4 1-2 Hiranomachi Chuo-ku, Osaka City Osaka Gas Co., Ltd.
Claims (4)
を、Ｃｕ、Ｃｏ、Ｍｎ、Ｆｅ、Ｎｉ、Ｚｎ及びＡｇから
選ばれた少なくとも１種類の金属を含有する、ゾルゲル
法により得られたシリカアルミナ系選択還元触媒を用い
て、排ガス中の窒素酸化物を炭化水素により選択的に還
元浄化することを特徴とする排ガス中の窒素酸化物の浄
化方法。1. A silica-alumina system obtained by a sol-gel method, wherein exhaust gas containing hydrocarbons and oxygen contains at least one metal selected from Cu, Co, Mn, Fe, Ni, Zn and Ag. A method for purifying nitrogen oxides in exhaust gas, which comprises selectively reducing and purifying nitrogen oxides in exhaust gas with hydrocarbons using a selective reduction catalyst.
ゾルゲル法触媒として、鉱酸又はその無水物と有機塩基
とを含み、当該有機塩基が水に実質的に不溶であり且つ
有機溶媒に可溶な第三アミンである触媒を用いて合成し
て得られたシリカアルミナ系触媒である請求項１記載の
排ガス中の窒素酸化物の浄化方法。2. The selective reduction catalyst contains, as a metal alkoxide sol-gel method catalyst, a mineral acid or an anhydride thereof and an organic base, the organic base being substantially insoluble in water and soluble in an organic solvent. The method for purifying nitrogen oxides in exhaust gas according to claim 1, which is a silica-alumina-based catalyst obtained by synthesis using a catalyst that is a tertiary amine.
素数３以上のパラフィン又は炭素数２以上のオレフィン
を添加して得られたガスである請求項１又は２記載の排
ガス中の窒素酸化物の浄化方法。3. The nitrogen oxide in the exhaust gas according to claim 1, wherein the exhaust gas is a gas obtained by adding paraffin having 3 or more carbon atoms or olefin having 2 or more carbon atoms to combustion exhaust gas of natural gas. Purification method.
カアルミナ系触媒であり、Ｃｕ含有量がシリカアルミナ
重量に対して０．５〜５重量％である請求項１から３の
何れかに記載の排ガス中の窒素酸化物の浄化方法。4. The selective reduction catalyst is a silica-alumina-based catalyst supporting Cu, and the Cu content is 0.5 to 5% by weight based on the weight of silica-alumina. Method for purifying nitrogen oxides in exhaust gas of automobiles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4300381A JPH06126134A (en) | 1992-10-13 | 1992-10-13 | Method for purification of nitrogen oxide in exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4300381A JPH06126134A (en) | 1992-10-13 | 1992-10-13 | Method for purification of nitrogen oxide in exhaust gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06126134A true JPH06126134A (en) | 1994-05-10 |
Family
ID=17884104
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4300381A Pending JPH06126134A (en) | 1992-10-13 | 1992-10-13 | Method for purification of nitrogen oxide in exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06126134A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002536422A (en) * | 1999-02-12 | 2002-10-29 | バイオストリーム インコーポレイテッド | Matrix for drug delivery, and methods of making and using the same |
| US6638485B1 (en) * | 1997-02-19 | 2003-10-28 | Mitsubishi Heavy Industries, Ltd. | Process for treating exhaust gas and exhaust gas treating equipment |
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| CN105664942A (en) * | 2016-01-23 | 2016-06-15 | 湖北工程学院 | Preparation method of microporous catalytic material for diesel oil tail gas treatment |
| US9375710B2 (en) | 2007-09-19 | 2016-06-28 | General Electric Company | Catalyst and method of manufacture |
| US9463438B2 (en) | 2009-01-30 | 2016-10-11 | General Electric Company | Templated catalyst composition and associated method |
| US9463439B2 (en) | 2009-01-30 | 2016-10-11 | General Electric Company | Templated catalyst composition and associated method |
| US9545618B2 (en) | 2011-06-21 | 2017-01-17 | General Electric Company | Method for preparing a catalyst composition suitable for removing sulfur from a catalytic reduction system |
| JP2019025389A (en) * | 2017-07-26 | 2019-02-21 | 国立大学法人 熊本大学 | Manufacturing method of ammonia combustion catalyst, and method of using heat generated by ammonia catalyst combustion |
-
1992
- 1992-10-13 JP JP4300381A patent/JPH06126134A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6638485B1 (en) * | 1997-02-19 | 2003-10-28 | Mitsubishi Heavy Industries, Ltd. | Process for treating exhaust gas and exhaust gas treating equipment |
| JP2002536422A (en) * | 1999-02-12 | 2002-10-29 | バイオストリーム インコーポレイテッド | Matrix for drug delivery, and methods of making and using the same |
| JP4812167B2 (en) * | 1999-02-12 | 2011-11-09 | モレキュラー インサイト ファーマスーティカルズ インコーポレイテッド | Drug transport matrix and methods for making and using the same |
| US9272271B2 (en) | 2007-09-19 | 2016-03-01 | General Electric Company | Manufacture of catalyst compositions and systems |
| US9375710B2 (en) | 2007-09-19 | 2016-06-28 | General Electric Company | Catalyst and method of manufacture |
| US9463438B2 (en) | 2009-01-30 | 2016-10-11 | General Electric Company | Templated catalyst composition and associated method |
| US9463439B2 (en) | 2009-01-30 | 2016-10-11 | General Electric Company | Templated catalyst composition and associated method |
| US9545618B2 (en) | 2011-06-21 | 2017-01-17 | General Electric Company | Method for preparing a catalyst composition suitable for removing sulfur from a catalytic reduction system |
| CN105664942A (en) * | 2016-01-23 | 2016-06-15 | 湖北工程学院 | Preparation method of microporous catalytic material for diesel oil tail gas treatment |
| CN105664942B (en) * | 2016-01-23 | 2018-05-25 | 湖北工程学院 | A kind of preparation method of micropore catalysis material for diesel exhaust processing |
| JP2019025389A (en) * | 2017-07-26 | 2019-02-21 | 国立大学法人 熊本大学 | Manufacturing method of ammonia combustion catalyst, and method of using heat generated by ammonia catalyst combustion |
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