JPH06154602A - Catalyst for removal of nitrogen oxide - Google Patents

Catalyst for removal of nitrogen oxide

Info

Publication number
JPH06154602A
JPH06154602A JP4339498A JP33949892A JPH06154602A JP H06154602 A JPH06154602 A JP H06154602A JP 4339498 A JP4339498 A JP 4339498A JP 33949892 A JP33949892 A JP 33949892A JP H06154602 A JPH06154602 A JP H06154602A
Authority
JP
Japan
Prior art keywords
catalyst
nox
carrier
reaction
atmosphere
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.)
Pending
Application number
JP4339498A
Other languages
Japanese (ja)
Inventor
Makoto Nakamura
良 中村
Takeshi Naganami
武 長南
Masao Wakabayashi
正男 若林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Metal Mining Co Ltd
Original Assignee
Sumitomo Metal Mining Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Mining Co Ltd filed Critical Sumitomo Metal Mining Co Ltd
Priority to JP4339498A priority Critical patent/JPH06154602A/en
Publication of JPH06154602A publication Critical patent/JPH06154602A/en
Pending legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
    • C01B21/24—Nitric oxide (NO)
    • C01B21/26—Preparation by catalytic or non-catalytic oxidation of ammonia
    • C01B21/265—Preparation by catalytic or non-catalytic oxidation of ammonia characterised by the catalyst
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Catalysts (AREA)

Abstract

PURPOSE:To considerably accelerate a reduction removal reaction of NOx with hydrocarbon in an excess oxygen-contg. atmosphere, to inhibit the formation of N2O and to increase N2 selectivity by preparing a catalyst obtd. by carrying Pt on an inorg. oxide carrier and incorporating acidic anions into the carrier after firing. CONSTITUTION:This catalyst for removal of NOx is a catalyst obtd. by carrying Pt on an inorg. oxide carrier and contains acidic anions in the carrier after firing. This catalyst considerably accelerates a reduction removal reaction of NOx contained in various exhaust gases such as exhaust gas from a boiler or the internal-combustion engine of an automobile, etc., and exhaust gas discharged from a nitric acid producing plant, etc., with hydrocarbon as a reducing agent. This catalyst is especially effective in a reduction reaction of NOx in an excess oxygen-contg. atmosphere, is characterized by a low rate of formation of NOx, that is, excellent N<2> selectivity and contributes to industrial profit or pollution control.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、排ガス、特に空燃比が
リーン側となる酸素過剰雰囲気の排ガスにおいてもＮＯ
ｘを浄化できる触媒に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be applied to NO even in exhaust gas, especially in exhaust gas in an oxygen excess atmosphere where the air-fuel ratio is on the lean side.
The present invention relates to a catalyst that can purify x.

【０００２】[0002]

【従来の技術】窒素酸化物（ＮＯｘ）は、ボイラーや自
動車などの内燃機関からの排ガスあるいは硝酸製造工場
等から排出される排ガス等の各種の排ガス中に含まれて
いるが、人体に有害な大気汚染物質であり、又、地球環
境保全の上から問題視される酸性雨の原因の一つでもあ
る。そのため、これら各種の排ガスから効率よくＮＯｘ
を除去する方法の開発が望まれている。理想的なＮＯｘ
除去技術は（１）式で示すところのＮＯ直接分解であ
る。 ２ＮＯ → Ｎ2 ＋ Ｏ2 （１） （１）式は平衡論的には右辺生成系に圧倒的に有利であ
って、例えば特開昭６０−１２５２５０号公報には、Ｃ
ｕをイオン交換によりゼオライトに担持させた触媒がＮ
Ｏの直接分解反応を促進させることが開示されている。
しかしながら、（１）式の反応は、生成した酸素が触媒
活性点に優先的に吸着するために徐々に除去効率が低下
し、さらに反応系内に過剰の酸素が存在する条件（酸素
過剰雰囲気）では完全に反応が阻害されてしまう。また
ＮＯｘを、触媒の存在下に、一酸化炭素、水素、炭化水
素、アンモニア、ヒドラジンなどの還元剤を用いて浄化
する方法は多数提案されている。これらＮＯｘの浄化に
使用するＮＯｘ浄化用触媒についても白金族元素を担体
に担持させた触媒をはじめとして、その他種々の触媒が
提案されている。2. Description of the Related Art Nitrogen oxides (NOx) are contained in various exhaust gases such as exhaust gases from internal combustion engines such as boilers and automobiles or exhaust gases from nitric acid manufacturing plants, etc., but are harmful to humans. It is an air pollutant and is one of the causes of acid rain, which is regarded as a problem from the viewpoint of global environmental protection. Therefore, NOx can be efficiently emitted from these various exhaust gases.
It is desired to develop a method for removing the above. Ideal NOx
The removal technique is direct decomposition of NO as shown in the equation (1). 2NO → N 2 + O 2 (1) The equation (1) is overwhelmingly advantageous to the right-hand side generation system in terms of equilibrium. For example, JP-A-60-125250 discloses C
The catalyst in which u is supported on zeolite by ion exchange is N
It is disclosed that the direct decomposition reaction of O is promoted.
However, in the reaction of the formula (1), the generated oxygen is preferentially adsorbed on the catalytic active site, so that the removal efficiency is gradually reduced, and further, the condition that excess oxygen exists in the reaction system (oxygen excess atmosphere) Then the reaction is completely hindered. Also, many methods have been proposed for purifying NOx in the presence of a catalyst using a reducing agent such as carbon monoxide, hydrogen, hydrocarbons, ammonia and hydrazine. As for the NOx purification catalysts used for purification of NOx, various other catalysts have been proposed, including a catalyst in which a platinum group element is supported on a carrier.

【０００３】しかしながら従来公知の触媒は、一酸化炭
素、炭化水素、水素などの還元剤を完全酸化するに必要
な理論酸素量よりも酸素が少ない雰囲気、すなわち還元
性雰囲気で使用した場合は良好なＮＯｘの浄化作用を示
すが、酸素量の多い酸素過剰雰囲気においては急激にＮ
Ｏｘの浄化率が低下するという難点があった。すなわ
ち、酸素過剰雰囲気におけるＮＯｘの接触還元において
は、共存する一酸化炭素、水素および炭化水素などの還
元剤の燃焼反応が併発し、還元反応の選択性は著しく低
下するという難点が生じ、酸素過剰雰囲気におけるＮＯ
ｘ浄化反応に有効な触媒は、未だ完成されていない。ま
た、従来の脱硝装置では排ガス中のＮ2 Ｏについては何
ら考慮されておらず、Ｎ2 Ｏは殆ど除去されていない。
化学発光式ＮＯｘ分析計はＮＯとＮＯ2 のみを計測し、
原理的にＮ2 Ｏを検出しないし、またＮＯ、ＮＯ2 に比
べてＮ2 Ｏの毒性が低く、現行の排出ガス規制ではＮＯ
ｘとして規定されていないが、最近の報告によればＮ2
Ｏはオゾン層破壊を引き起こす原因物質の一つであると
されており、半減期が約１５０年と長く発生量も多いと
いわれている。However, conventionally known catalysts are preferable when used in an atmosphere containing less oxygen than the theoretical amount of oxygen required to completely oxidize reducing agents such as carbon monoxide, hydrocarbons and hydrogen, that is, in a reducing atmosphere. Although it has a purifying effect on NOx, it rapidly abates in an oxygen-rich atmosphere with a large amount of oxygen.
There is a drawback that the purification rate of Ox is lowered. That is, in the catalytic reduction of NOx in an oxygen-excess atmosphere, the combustion reaction of coexisting reducing agents such as carbon monoxide, hydrogen, and hydrocarbons occurs concurrently, and the selectivity of the reduction reaction remarkably deteriorates. NO in atmosphere
A catalyst effective for x purification reaction has not been completed yet. Further, in the conventional denitration apparatus, no consideration is given to N 2 O in exhaust gas, and N 2 O is hardly removed.
The chemiluminescent NOx analyzer measures only NO and NO 2 .
It does not detect the theoretically N 2 O, also NO, compared to NO 2 N 2 O of low toxicity, NO in the current emission regulations
Not specified as x, but recent reports indicate N 2
O is said to be one of the causative substances that cause ozone layer depletion, and is said to have a long half-life of about 150 years and a large amount of O.

【０００４】白金族元素を担持した触媒については自動
車排ガス処理触媒としてだけでなく、燃焼触媒や石油化
学の分野における改質触媒としても多くの研究がなされ
ている。従来、これらの白金族元素触媒にとって塩酸痕
Ｃｌ- や硫酸痕ＳＯ4 2- は触媒毒として作用することが
知られており、白金族元素の原料や担体原料から塩酸痕
や硫酸痕を除去することにより触媒活性の向上が図られ
てきた。例えば触媒学会主催１９８８年触媒研究発表会
３Ｂ２２４では塩素を含まないパラジウム塩を原料に用
いると、Ｐｄ／Ａｌ2 Ｏ3 触媒のメタン酸化活性が、塩
素を含む場合に比べて大幅に向上することが報告されて
いる。Many studies have been conducted on catalysts carrying platinum group elements, not only as automobile exhaust gas treatment catalysts but also as combustion catalysts and reforming catalysts in the field of petrochemistry. It has been conventionally known that hydrochloric acid traces Cl − and sulfuric acid traces SO 4 2− act as catalyst poisons for these platinum group element catalysts, and remove hydrochloric acid traces and sulfuric acid traces from platinum group element raw materials and carrier raw materials. As a result, the catalytic activity has been improved. For example, in the 1988 Catalyst Research Presentation 3B224 sponsored by the Catalysis Society, when a palladium salt containing no chlorine was used as a raw material, the methane oxidation activity of the Pd / Al 2 O 3 catalyst was significantly improved as compared with the case where chlorine was contained. It has been reported.

【０００５】本出願人らは既に、Ｐｔを担体に担持した
触媒を用い、炭化水素を還元剤に用いる酸素過剰雰囲気
での脱硝プロセスを考案し提案しているが、ＮＯｘ還元
反応の主な生成物はＮ2 とＮ2 Ｏであった（特願平３−
１０５６６８）。これは、酸素過剰の排ガス中ではＮＯ
は触媒上で酸化されてＮＯ2 に変換されて、しかる後に
還元されてＮ2 とＮ2 Ｏに変換されることに起因するも
のと推測される。このため、酸素過剰雰囲気のＮＯｘ還
元反応におけるＮ2 選択性向上が切望されている。The present applicants have already devised and proposed a denitration process in an oxygen excess atmosphere using a catalyst in which Pt is supported on a carrier and using hydrocarbon as a reducing agent, but the main generation of NOx reduction reaction. The objects were N 2 and N 2 O (Japanese Patent Application No. 3-
105668). This is NO in exhaust gas with excess oxygen.
Is presumed to be caused by being oxidized on the catalyst and converted into NO 2 , and then reduced and converted into N 2 and N 2 O. Therefore, improvement of N 2 selectivity in the NOx reduction reaction in an oxygen excess atmosphere has been earnestly desired.

【０００６】[0006]

【発明が解決しようとする課題】本発明は上記事情に鑑
みてなされたものであり、炭化水素を還元剤とする、酸
素過剰雰囲気におけるＮＯｘ還元反応に有効な触媒であ
って、Ｎ2 Ｏの生成割合の低い、言い換えればＮＯｘを
選択的にＮ2 に変換することのできる触媒を提供するこ
とを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and is a catalyst effective for NOx reduction reaction using hydrocarbon as a reducing agent in an oxygen-excess atmosphere and containing N 2 O 3. It is an object of the present invention to provide a catalyst having a low production rate, in other words, capable of selectively converting NOx to N 2 .

【０００７】[0007]

【課題を解決するための手段】本発明は、Ｐｔを無機酸
化物担体に担持した触媒であって、焼成後の担体中に酸
性陰イオンが含有することを特徴とする窒素酸化物浄化
用触媒であり、また前記酸性陰イオンが、ＳＯ4 2- 、Ｃ
ｌ- であることを特徴とする。The present invention is a catalyst in which Pt is supported on an inorganic oxide carrier, wherein the carrier after calcination contains acidic anions. And the acidic anion is SO 4 2- , C
It is characterized by being l − .

【０００８】[0008]

【作用】本発明者らは鋭意研究を重ねた結果、あらかじ
め担体原料の無機酸化物をＨ2ＳＯ4 、ＨＣｌなどの鉱
酸で処理した担体に白金を担持した触媒を用いると、酸
素過剰雰囲気において炭化水素による窒素酸化物の還元
除去反応が大いに促進され、しかもＮ2 Ｏの生成が抑制
されてＮ2 の選択率が向上するという驚くべき事実を見
いだした。これは、焼成後の担体中に存在する酸性陰イ
オンが担体の固体酸性質を向上させ、ＮＯｘの吸着容量
を増大させると同時に、Ｐｔの炭化水素燃焼活性を抑制
し、還元剤である炭化水素がＮＯｘに有効に作用せしめ
ることができたものと考えられる。As a result of intensive studies, the inventors of the present invention have found that when a catalyst in which platinum is supported on a carrier prepared by previously treating an inorganic oxide as a carrier raw material with a mineral acid such as H 2 SO 4 or HCl is used, an oxygen-rich atmosphere In the above, the surprising fact was found that the reduction and removal reaction of nitrogen oxides by hydrocarbons is greatly promoted, and the production of N 2 O is suppressed to improve the selectivity of N 2 . This is because the acidic anions existing in the carrier after calcination improve the solid acid properties of the carrier and increase the NOx adsorption capacity, and at the same time suppress the hydrocarbon combustion activity of Pt and reduce the hydrocarbon as a reducing agent. Is believed to have been able to effectively act on NOx.

【０００９】本発明で担体原料として使用することので
きる無機酸化物はアルミナ、チタニア、ジルコニアなど
であって結晶質であるか非晶質であるかは重要ではな
い。これら担体の形状は、球状、円筒状、ハニカム状、
棒状、ラセン状、粒状など特に制限されることはなく、
形状、大きさなどは使用条件に応じて任意に選択するこ
とができる。本発明で用いる担体は、アルミナ、チタニ
ア、ジルコニアなどの担体原料に酸性陰イオンを含有さ
せることによって調製される。酸性陰イオンはＢ
Ｏ3 3- 、ＳＯ4 2- 、Ｃｌ- 、ＰＯ4 3- からなる群から選
ばれた少なくとも１種の陰イオンを使用することが好ま
しく、ＣＯ3 2- 、ＮＯ3 - 或はＣＨ3 ＣＯＯ- などの有
機酸イオンは焼成処理時に脱離してしまい担体中に残存
させることが困難であるので、前記ＢＯ3 3- 、Ｓ
Ｏ4 2- 、Ｃｌ- 、ＰＯ4 3- イオンが適している。とくに
ＳＯ4 2- 、Ｃｌ- が好ましい。これら酸性陰イオンの原
料はＨ3 ＢＯ3 、Ｈ2 ＳＯ4 、ＨＣｌ、Ｈ3 ＰＯ4 など
の鉱酸や、ホウ酸アルミニウム、硫酸アルミニウム、塩
化アルミニウム、燐酸アルミニウム、硫酸チタン、四塩
化チタン、三塩化チタン、塩化ジルコニウム、硫酸ジル
コニウムなどの塩を使用することができる。The inorganic oxide that can be used as the carrier raw material in the present invention is alumina, titania, zirconia or the like, and it is not important whether it is crystalline or amorphous. The shapes of these carriers are spherical, cylindrical, honeycomb,
There is no particular limitation such as rod shape, spiral shape, granular shape,
The shape, size, etc. can be arbitrarily selected according to the usage conditions. The carrier used in the present invention is prepared by incorporating a carrier raw material such as alumina, titania or zirconia with an acidic anion. Acidic anion is B
It is preferable to use at least one anion selected from the group consisting of O 3 3− , SO 4 2− , Cl − , and PO 4 3− , CO 3 2− , NO 3 − or CH 3 COO. - since the organic acid ions such as it is difficult to remain in a carrier will be desorbed during the firing process, the BO 3 3-, S
O 4 2− , Cl − , PO 4 3− ions are suitable. SO 4 2− and Cl − are particularly preferable. The raw materials for these acidic anions are mineral acids such as H 3 BO 3 , H 2 SO 4 , HCl, and H 3 PO 4 , and aluminum borate, aluminum sulfate, aluminum chloride, aluminum phosphate, titanium sulfate, titanium tetrachloride, and trisodium chloride. Salts such as titanium chloride, zirconium chloride and zirconium sulfate can be used.

【００１０】酸性陰イオンを含有する担体の調製方法
は、担体原料である無機酸化物と酸性陰イオン原料とを
混合する種々の方法を使用することが可能であって、特
に限定するものではないが、一例を挙げれば、アルミナ
水和物粉体に硫酸Ｈ2 ＳＯ4 を加えて８０〜９０℃の温
度に保って捏和・混練して反応させ、得られたケーキを
１２０℃で乾燥し、さらに４００〜６００℃の温度で焼
成すればよい。本担体は焼成工程に於て大部分の硫酸が
亜硫酸ガスとして飛散してしまうため、完成担体中に含
まれる硫酸痕ＳＯ4 2- は酸化物基準で０．１〜２．０ｗ
ｔ％程度である。As a method for preparing a carrier containing an acidic anion, various methods of mixing an inorganic oxide, which is a starting material for a carrier, and an acidic anion starting material can be used and are not particularly limited. However, to give an example, sulfuric acid H 2 SO 4 is added to alumina hydrate powder, and the mixture is kneaded and kneaded at a temperature of 80 to 90 ° C. to react, and the obtained cake is dried at 120 ° C. Further, it may be fired at a temperature of 400 to 600 ° C. Since most of the sulfuric acid scatters as sulfurous acid gas during the firing step, the sulfuric acid trace SO 4 2- contained in the finished carrier is 0.1 to 2.0 w on the oxide basis.
It is about t%.

【００１１】本発明で使用するＰｔ原料は塩化白金（I
V) 酸６水和物、塩化アンモニウム白金（IV) などの白
金酸塩あるいは白金テトラアンミン錯体２塩化物、白金
テトラアンミン錯体硝酸塩などの白金錯塩を使用するこ
とができる。塩化白金（II）酸カリウム、塩化白金（I
V）酸カリウム、塩化白金（II）酸ナトリウム６水和物
は完成触媒中にアルカリ金属イオンを含有することにな
り、酸性陰イオンの作用を相殺することになるので好ま
しくない。Ｐｔ塩水溶液は上記の白金酸、白金酸塩ある
いは白金錯塩を蒸留水あるいはイオン交換水に溶解して
調製する。溶液中のＰｔの濃度は、使用する全溶液中の
Ｐｔ総量が、完成触媒に対しＰｔの触媒有効量が担持で
きるに足る量の範囲にあればよく、必要に応じて適宜調
整することができる。イオン交換法や浸漬法において使
用するＰｔ塩水溶液の量は担体としての無機酸化物にＰ
ｔ塩が十分に含浸することができる量であれば特に限定
するものではないが、通常担体の約２〜２０倍程度が適
当である。インシピエント・ウェットネス法において使
用するＰｔ塩水溶液の量は担体としての多孔質無機酸化
物が、その細孔構造中に吸蔵することのできる水分量で
あって、含浸処理に先だって担体として使用する無機酸
化物の吸水量を測定して決定される。The Pt raw material used in the present invention is platinum chloride (I
V) Acid hexahydrate, platinate such as ammonium (IV) chloride chloride, or platinum complex salt such as platinum tetraammine complex dichloride and platinum tetraammine complex nitrate can be used. Potassium chloroplatinate (II), platinum chloride (I
Potassium V) acid and sodium hexachloroplatinate (II) hexahydrate are not preferable because the finished catalyst will contain an alkali metal ion, which will cancel the action of the acidic anion. The Pt salt aqueous solution is prepared by dissolving the above-mentioned platinic acid, platinate or platinum complex salt in distilled water or ion-exchanged water. The concentration of Pt in the solution may be in a range such that the total amount of Pt in all the solutions used can support the catalytically effective amount of Pt in the finished catalyst, and can be appropriately adjusted as necessary. . The amount of the Pt salt aqueous solution used in the ion exchange method or the immersion method depends on the amount of P added to the inorganic oxide as a carrier.
The amount is not particularly limited as long as the t salt can be sufficiently impregnated, but about 2 to 20 times the carrier is usually suitable. The amount of the Pt salt aqueous solution used in the incipient wetness method is the amount of water which the porous inorganic oxide as a carrier can occlude in its pore structure, and the amount of the inorganic used as a carrier prior to the impregnation treatment. It is determined by measuring the water absorption of the oxide.

【００１２】本発明においてＰｔの担持量は種々変化さ
せることができるが、担体に対して０．０５〜５ｗｔ
％、好ましくは０．１〜１ｗｔ％が適当である。前記範
囲よりＰｔ担持量が少ないと十分に触媒活性が発揮され
ず、また前記範囲より多くしても特に担持量の増加にと
もなう触媒活性の向上はないのでＰｔが高価であること
を考慮すると、前記範囲が適当である。上記の方法で所
定量の白金を含有させた担体を、常法に従い乾燥し、焼
成して本発明で使用する触媒を完成する。焼成工程は空
気雰囲気で４００〜６００℃の温度で行なうことが経済
的にも、また触媒活性、触媒の耐久性などからみても好
適である。In the present invention, the supported amount of Pt can be variously changed, but 0.05 to 5 wt% with respect to the carrier.
%, Preferably 0.1 to 1 wt% is suitable. Considering that Pt is expensive, the catalytic activity is not sufficiently exhibited when the amount of Pt supported is less than the above range, and there is no improvement in the catalytic activity particularly with an increase in the amount supported even when the amount is greater than the above range. The above range is suitable. The carrier containing a predetermined amount of platinum by the above method is dried and calcined according to a conventional method to complete the catalyst used in the present invention. It is preferable to carry out the firing step in an air atmosphere at a temperature of 400 to 600 ° C. economically, from the viewpoint of catalytic activity and durability of the catalyst.

【００１３】本発明の触媒および製造方法に依って製造
された触媒は、ボイラーや自動車などの内燃機関からの
排ガスあるいは硝酸製造工場等から排出される排ガス等
の各種の排ガス中に含まれている窒素酸化物を炭化水素
を還元剤として還元・浄化する反応を大いに促進し、特
に酸素過剰雰囲気におけるＮＯｘ還元反応に有効な触媒
であって、Ｎ2 Ｏの生成割合の低い、言い換えればＮ2
選択性にすぐれるという大きな特長を有するものであっ
て、工業上または公害対策上において貢献するところ極
めて大なるものである。The catalyst and the catalyst produced by the production method of the present invention are contained in various exhaust gases such as exhaust gases from internal combustion engines such as boilers and automobiles, and exhaust gases emitted from nitric acid manufacturing plants and the like. the hydrocarbon nitrogen oxides greatly facilitate reduction and purification reacts as a reducing agent, a catalyst effective especially NOx reduction reaction in an oxygen-rich atmosphere, low production ratio of N 2 O, in other words N 2
It has a great feature that it has excellent selectivity, and it is an extremely great place to contribute in industrial or pollution control.

【００１４】[0014]

【実施例】以下に実施例を参照しながら本発明をさらに
詳細に説明するが、本発明はこれら実施例にのみに限定
されるものでないことは言うまでもない。実施例１ ５０℃に保持した温水１０００ｍｌ中に硝酸アルミニウ
ム２０ｗｔ％水溶液１００ｇを加えて攪拌し、更に攪拌
しながらアルミン酸ナトリウム水溶液２０ｗｔ％水溶液
１００ｇを滴下して水酸化アルミニウムの白色沈澱を生
成させる。これを濾過、洗浄、脱水した後、空気中１２
０℃で１２時間乾燥してアルミナ水和物粉体３０ｇを得
た。The present invention will be described in more detail with reference to the following examples, but it goes without saying that the present invention is not limited to these examples. Example 1 100 g of a 20 wt% aqueous solution of aluminum nitrate was added to 1000 ml of warm water maintained at 50 ° C. and stirred, and 100 g of a 20 wt% aqueous solution of sodium aluminate was added dropwise with stirring to form a white precipitate of aluminum hydroxide. After filtering, washing and dehydrating this,
It was dried at 0 ° C. for 12 hours to obtain 30 g of alumina hydrate powder.

【００１５】このアルミナ水和物粉体２０ｇにＩＮ硫酸
水溶液１０ｍｌを添加し、更に適宜水を加えながらニー
ダー中８０〜９０℃に保持したまま２時間捏和混練す
る。得られたゲルを空気中１２０℃で１２時間乾燥し、
更に空気中５００℃で３時間焼成してイオウ含有アルミ
ナ１４ｇを得た。元素分析結果から本イオウ含有アルミ
ナ担体中のイオウ含有量は酸化物（ＳＯ4 ）基準で１．
２ｗｔ％であり、イオウ、アルミニウム、酸素以外の元
素として０．１ｗｔ％のナトリウムを含有した。また、
本イオウ含有アルミナ担体の比表面積は窒素吸着法によ
れば２８０ｍ2 ／ｇであり、吸水量は２．９ｍｌ／ｇで
あった。To 20 g of this alumina hydrate powder, 10 ml of an IN sulfuric acid aqueous solution was added, and kneading and kneading were continued for 2 hours while maintaining the temperature at 80 to 90 ° C. in a kneader while adding water appropriately. The gel obtained is dried in air at 120 ° C. for 12 hours,
Further, it was calcined in air at 500 ° C. for 3 hours to obtain 14 g of sulfur-containing alumina. Sulfur content of the sulfur-containing alumina carrier elemental analysis results oxide 1 (SO 4) criteria.
It was 2 wt%, and contained 0.1 wt% sodium as an element other than sulfur, aluminum and oxygen. Also,
According to the nitrogen adsorption method, the specific surface area of the sulfur-containing alumina carrier was 280 m 2 / g, and the water absorption amount was 2.9 ml / g.

【００１６】溶液１００ｍｌ中にＰｔ金属として１ｇを
含有する塩化白金酸水溶液１０ｍｌをイオン交換水で希
釈して総量２９ｍｌの塩化白金酸水溶液を調製する。こ
の塩化白金酸水溶液を本イオウ含有アルミナ担体１０ｇ
に徐々に加えながら機械的な攪拌を続け、白金酸水溶液
をイオウ含有アルミナに含浸する。これを空気中１２０
℃で乾燥し、さらに空気中５００℃で３時間焼成して触
媒１を得た。原子吸光分析から得られた触媒１の白金担
持率は１．０ｗｔ％であった。10 ml of a chloroplatinic acid aqueous solution containing 1 g of Pt metal in 100 ml of a solution is diluted with ion-exchanged water to prepare a total amount of 29 ml of a chloroplatinic acid aqueous solution. This chloroplatinic acid aqueous solution was added with 10 g of this sulfur-containing alumina carrier.
The mechanical agitation is continued while being gradually added, and the aqueous solution of platinum acid is impregnated into the sulfur-containing alumina. 120 in the air
It was dried at ℃, and further calcined in air at 500 ℃ for 3 hours to obtain catalyst 1. The platinum loading rate of the catalyst 1 obtained from the atomic absorption analysis was 1.0 wt%.

【００１７】触媒１を２５０〜５００μｍの粒径に揃え
たもの１ｇを内径１０ｍｍのステンレス製反応管に充填
し、これに反応ガス（ガス組成 ＮＯ：１，０００ｐｐ
ｍ，Ｃ3 Ｈ6 ：１，０００ｐｐｍ，Ｏ2 ：５ｖｏｌ％，
Ｈｅ：残量）を３０ｍｌ／ｍｉｎの流速で通過させた。
反応管出口ガス組成は、ＮＯとＮＯ2 の濃度については
化学発光式のＮＯｘ分析計で測定し、Ｎ2 Ｏ濃度はシリ
カゲルカラムを装着したガスクロマトグラフ−熱伝導度
検出器を用いて測定した。触媒層の温度は１００〜４０
０℃の範囲の所定温度に設定されており、反応管出口ガ
ス組成が定常となった時点の値を測定値として採用し
た。結果を表１に示した。反応ガスが触媒を通過するこ
とにより、反応ガス中のＮＯはＮＯ2 とＮ2 Ｏ、Ｎ2 に
転換せしめられるが、ＮＯ転化率、Ｎ2 Ｏ生成率、Ｎ2
生成率を以下のように定義した。 本発明ではＮＯの浄化率は、上記のＮ2 生成率で評価す
る。1 g of the catalyst 1 having a particle size of 250 to 500 μm is packed into a stainless steel reaction tube having an inner diameter of 10 mm, and a reaction gas (gas composition NO: 1,000 pp) is added to the reaction tube.
m, C 3 H 6 : 1,000 ppm, O 2 : 5 vol%,
He: residual amount) was passed at a flow rate of 30 ml / min.
The composition of the gas at the outlet of the reaction tube was measured for the concentrations of NO and NO 2 with a chemiluminescence type NOx analyzer, and the concentration of N 2 O was measured with a gas chromatograph-thermal conductivity detector equipped with a silica gel column. The temperature of the catalyst layer is 100-40
The temperature was set to a predetermined temperature in the range of 0 ° C., and the value at the time when the reaction tube outlet gas composition became steady was adopted as the measured value. The results are shown in Table 1. When the reaction gas passes through the catalyst, NO in the reaction gas is converted into NO 2 , N 2 O and N 2 , but the NO conversion rate, N 2 O production rate, N 2
The production rate was defined as follows. In the present invention, the NO purification rate is evaluated by the above N 2 production rate.

【００１８】実施例２ 実施例１と同じ方法で調製したアルミナ水和物粉体２０
ｇに１Ｎ塩化水素水溶液１０ｍｌを添加し、実施例と同
じ方法で塩素含有アルミナ１４ｇを得た。元素分析結果
から本塩素含有アルミナ中の塩素含有量は０．８６ｗｔ
％であった。この塩素含有アルミナを実施例１と同じ方
法で触媒化して白金担持率が１．０ｗｔ％の触媒２を調
製し、活性を評価した。その結果を表１に示した。 Example 2 Alumina hydrate powder 20 prepared by the same method as in Example 1
10 g of 1N hydrogen chloride aqueous solution was added to g to obtain 14 g of chlorine-containing alumina in the same manner as in the example. From the elemental analysis result, the chlorine content in the chlorine-containing alumina is 0.86 wt.
%Met. This chlorine-containing alumina was catalyzed by the same method as in Example 1 to prepare a catalyst 2 having a platinum loading rate of 1.0 wt%, and its activity was evaluated. The results are shown in Table 1.

【００１９】比較例 １Ｎ硫酸水溶液をアルミナ水和物粉体に添加しないこと
以外は、実施例１と同様の方法によってアルミナ担体を
調製し、これに実施例１と同じ方法で白金を担持して白
金担持率が１．０ｗｔ％の触媒３を得た。アルミナ担体
３Ａの比表面積は窒素吸着法によれば２８０ｍ2 ／ｇで
あり、吸水量は２．９ｍｌ／ｇであった。実施例１と同
様の方法で活性を評価した。その結果を表１に示した。 Comparative Example 1 An alumina carrier was prepared in the same manner as in Example 1 except that the aqueous solution of 1N sulfuric acid was not added to the alumina hydrate powder, and platinum was loaded on the carrier in the same manner as in Example 1. A catalyst 3 having a platinum loading of 1.0 wt% was obtained. According to the nitrogen adsorption method, the specific surface area of the alumina carrier 3A was 280 m 2 / g, and the water absorption amount was 2.9 ml / g. The activity was evaluated in the same manner as in Example 1. The results are shown in Table 1.

【００２０】[0020]

【表１】 [Table 1]

【００２１】表１より、反応温度が３００℃以下の温度
範囲において、焼成後の担体中に１．２ｗｔ％のＳＯ4
2- イオンあるいは０．８６ｗｔ％のＣｌ- イオンが含
有する白金触媒は、ＳＯ4 2- 、Ｃｌ- イオンが含有しな
い白金触媒よりＮ2 生成率が高くなることが判る。From Table 1, 1.2 wt% of SO 4 is contained in the carrier after firing in the reaction temperature range of 300 ° C. or lower.
It can be seen that the platinum catalyst containing 2- ions or 0.86 wt% Cl − ions has a higher N 2 production rate than the platinum catalyst containing no SO 4 2− or Cl − ions.

【００２２】[0022]

【発明の効果】以上説明してきたように、本発明によれ
ば、酸素過剰雰囲気において炭化水素による窒素酸化物
の還元除去反応が大いに促進され、しかもＮ2 Ｏの生成
が抑制されてＮ2 の選択率が向上する。As described above, according to the present invention, the reduction and removal reaction of nitrogen oxides by hydrocarbons is greatly promoted in an oxygen excess atmosphere, and the production of N 2 O is suppressed, so that the N 2 Selectivity is improved.

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 Ｐｔを無機酸化物担体に担持した触媒で
あって、焼成後の担体中に酸性陰イオンが含有すること
を特徴とする窒素酸化物浄化用触媒。1. A catalyst for purifying nitrogen oxides, which is a catalyst in which Pt is supported on an inorganic oxide carrier, and an acidic anion is contained in the carrier after firing. 【請求項２】 酸性陰イオンがＳＯ4 2- 、Ｃｌ- である
ことを特徴とする請求項１に記載の窒素酸化物浄化用触
媒。2. The catalyst for purifying nitrogen oxides according to claim 1, wherein the acidic anion is SO 4 2− or Cl − .
JP4339498A 1992-11-27 1992-11-27 Catalyst for removal of nitrogen oxide Pending JPH06154602A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4339498A JPH06154602A (en) 1992-11-27 1992-11-27 Catalyst for removal of nitrogen oxide

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4339498A JPH06154602A (en) 1992-11-27 1992-11-27 Catalyst for removal of nitrogen oxide

Publications (1)

Publication Number Publication Date
JPH06154602A true JPH06154602A (en) 1994-06-03

Family

ID=18328045

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4339498A Pending JPH06154602A (en) 1992-11-27 1992-11-27 Catalyst for removal of nitrogen oxide

Country Status (1)

Country Link
JP (1) JPH06154602A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000061308A (en) * 1998-06-08 2000-02-29 Osaka Gas Co Ltd Catalyst and method for cleaning exhaust gas
JP2000342972A (en) * 1999-06-02 2000-12-12 Osaka Gas Co Ltd Catalyst for purifying exhaust gas and exhaust gas purifying method
JP2013169480A (en) * 2012-02-17 2013-09-02 Osaka Gas Co Ltd Methane oxidation catalyst and method of manufacturing the same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000061308A (en) * 1998-06-08 2000-02-29 Osaka Gas Co Ltd Catalyst and method for cleaning exhaust gas
JP2000342972A (en) * 1999-06-02 2000-12-12 Osaka Gas Co Ltd Catalyst for purifying exhaust gas and exhaust gas purifying method
JP2013169480A (en) * 2012-02-17 2013-09-02 Osaka Gas Co Ltd Methane oxidation catalyst and method of manufacturing the same

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