JPH0696094B2 - Exhaust gas purification method - Google Patents
Exhaust gas purification methodInfo
- Publication number
- JPH0696094B2 JPH0696094B2 JP3280825A JP28082591A JPH0696094B2 JP H0696094 B2 JPH0696094 B2 JP H0696094B2 JP 3280825 A JP3280825 A JP 3280825A JP 28082591 A JP28082591 A JP 28082591A JP H0696094 B2 JPH0696094 B2 JP H0696094B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- silver
- ceramic layer
- porous ceramic
- nox
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 46
- 238000000746 purification Methods 0.000 title claims description 25
- 239000007789 gas Substances 0.000 claims description 102
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 53
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 claims description 44
- 239000000919 ceramic Substances 0.000 claims description 35
- 239000000463 material Substances 0.000 claims description 33
- 229910052709 silver Inorganic materials 0.000 claims description 30
- 239000004332 silver Substances 0.000 claims description 30
- 229930195733 hydrocarbon Natural products 0.000 claims description 28
- 150000002430 hydrocarbons Chemical class 0.000 claims description 28
- 239000004215 Carbon black (E152) Substances 0.000 claims description 25
- 229910001923 silver oxide Inorganic materials 0.000 claims description 22
- 239000007788 liquid Substances 0.000 claims description 19
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical group [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 17
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 8
- 238000011144 upstream manufacturing Methods 0.000 claims description 6
- 238000009835 boiling Methods 0.000 claims description 5
- 239000003638 chemical reducing agent Substances 0.000 claims description 5
- 239000002131 composite material Substances 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 28
- 239000010410 layer Substances 0.000 description 28
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 15
- 239000001301 oxygen Substances 0.000 description 15
- 229910052760 oxygen Inorganic materials 0.000 description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 11
- 238000002485 combustion reaction Methods 0.000 description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 8
- 238000000576 coating method Methods 0.000 description 7
- 239000003921 oil Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 6
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 5
- 239000003054 catalyst Substances 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 239000003502 gasoline Substances 0.000 description 4
- 229910001961 silver nitrate Inorganic materials 0.000 description 4
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 description 4
- 238000003980 solgel method Methods 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 150000004703 alkoxides Chemical class 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- -1 naphtha Substances 0.000 description 3
- 239000003208 petroleum Substances 0.000 description 3
- 239000001294 propane Substances 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 238000001879 gelation Methods 0.000 description 2
- JEGUKCSWCFPDGT-UHFFFAOYSA-N h2o hydrate Chemical compound O.O JEGUKCSWCFPDGT-UHFFFAOYSA-N 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000003350 kerosene Substances 0.000 description 2
- 229910052863 mullite Inorganic materials 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000011538 cleaning material Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、自動車エンジン等の内
燃機関より排出される排ガスを浄化する方法に関し、特
に、ディーゼルエンジン等の排ガス中に含まれる窒素酸
化物を効果的に還元除去することができる排ガス浄化方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying exhaust gas discharged from an internal combustion engine such as an automobile engine, and more particularly to effectively reducing and removing nitrogen oxides contained in the exhaust gas such as a diesel engine. The present invention relates to an exhaust gas purification method capable of achieving the above.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】近年、
地球規模の環境汚染が問題となってきているが、中でも
大気汚染は特に大都市圏において深刻であり、大気中の
窒素酸化物（以下NOx と呼ぶ）による光化学スモッグ
や、酸性雨等の問題が未解決のまま残っている。NOx の
発生源としては、自動車のエンジン、とりわけディーゼ
ルエンジンや大型の燃焼装置（たとえばコジェネレーシ
ョン用内燃機関）等が挙げられる。2. Description of the Related Art In recent years,
Global environmental pollution has become a problem, but air pollution is particularly serious in metropolitan areas, and problems such as photochemical smog due to nitrogen oxides (hereinafter referred to as NOx) in the atmosphere and acid rain are present. It remains unresolved. Sources of NOx include automobile engines, especially diesel engines and large combustion devices (for example, cogeneration internal combustion engines).
【０００３】排ガス中のNOx を除去する方法には、たと
えばガソリンエンジンの排ガスに対しては、いわゆる３
元触媒を用いる方法があり、また、大規模な固定燃焼装
置（工場等の大型燃焼機等）に対しては、排ガスにアン
モニアを混入し、これにより排ガス中の窒素酸化物を還
元する選択的接触還元法がある。A method for removing NOx in exhaust gas is known as, for example, so-called 3 for exhaust gas of a gasoline engine.
There is a method that uses an original catalyst, and for large-scale fixed combustion equipment (large combustors such as factories), ammonia is mixed into the exhaust gas, which selectively reduces nitrogen oxides in the exhaust gas. There is a catalytic reduction method.
【０００４】しかしながら、ディーゼルエンジンから排
出される排ガスのように、酸素濃度が比較的高い排ガス
に対しては、ガソリンエンジンの排ガス浄化に用いられ
る従来の３元触媒方式では効率のよいNOx の除去は行え
ない。また、排ガスにアンモニアを混入してNOx を還元
除去する方法は、アンモニアが高価であること、また装
置が大型になること等の問題点があり、自動車等の移動
する排ガス発生源には適用できない。However, for exhaust gas with a relatively high oxygen concentration, such as exhaust gas emitted from a diesel engine, the conventional three-way catalyst system used for purifying exhaust gas of a gasoline engine cannot efficiently remove NOx. I can't do it. In addition, the method of reducing and removing NOx by mixing ammonia in exhaust gas has problems such as expensive ammonia and large-sized device, and cannot be applied to moving exhaust gas sources such as automobiles. .
【０００５】したがって、ディーゼルエンジンの排ガス
等にみられるような酸素濃度が比較的高い排ガス中のNO
x を低減（除去）する新規な方法の確立が望まれてお
り、これまでに様々な試みがなされてきた。Therefore, NO in exhaust gas having a relatively high oxygen concentration as found in exhaust gas of diesel engines, etc.
It is desired to establish a new method for reducing (eliminating) x, and various attempts have been made so far.
【０００６】たとえば、排ガス中に炭化水素を導入し
て、この炭化水素により排ガス中のNOx を還元除去する
方法がある。その一例として、特公昭４４−１３００２
号には、白金族触媒を担持したハニカム状のセラミック
成形体に温度及び流量を制御しながら排ガスを通すとと
もに、ガス状の還元性燃料（具体的にはメタン等）を添
加する方法が開示されている。For example, there is a method of introducing a hydrocarbon into the exhaust gas and reducing and removing NOx in the exhaust gas by the hydrocarbon. As an example, Japanese Patent Publication No. 44-13002
JP-A No. 2003-187242 discloses a method of passing exhaust gas through a honeycomb-shaped ceramic molded body carrying a platinum group catalyst while controlling temperature and flow rate, and adding a gaseous reducing fuel (specifically, methane or the like). ing.
【０００７】しかしながら、この方法ではディーゼルエ
ンジン等の排ガス中のNOx を効率よく還元するには十分
ではない。本発明者等の研究によれば、ディーゼルエン
ジンの排ガスに対し、標準状態でガス状となる低炭素数
の炭化水素（メタン、プロパン等）をNOx の還元剤とし
て添加しても、それ程大きなNOx 除去率が得られないこ
とがわかった。However, this method is not sufficient to efficiently reduce NOx in exhaust gas from a diesel engine or the like. According to the research conducted by the present inventors, even if a low carbon number hydrocarbon (methane, propane, etc.), which becomes gaseous in a standard state, is added to the exhaust gas of a diesel engine as a NOx reducing agent, the NOx is so large. It was found that the removal rate could not be obtained.
【０００８】また、酸素及びNOx を含有する排ガスに炭
化水素を混合し、酸素と炭化水素とを反応させて炭化水
素を部分酸化させ、還元性の水素と一酸化炭素に変性さ
せるとともに酸素濃度を減少させた上、この生成変性ガ
スと排ガスに含まれるNOx とを反応させて、窒素、炭酸
ガス及び水に分解する方法（特開昭４９−１２２４７４
号）もあるが、この方法ではNOx の還元反応を６００℃
程度の比較的高温で行わなければならず、自動車の排ガ
ス浄化には適さない。Further, a hydrocarbon is mixed with exhaust gas containing oxygen and NOx, and the oxygen and the hydrocarbon are reacted with each other to partially oxidize the hydrocarbon to modify it into reducing hydrogen and carbon monoxide. In addition to reducing the amount, the generated modified gas is reacted with NOx contained in the exhaust gas to decompose it into nitrogen, carbon dioxide gas and water (JP-A-49-122474).
No.), but with this method, the NOx reduction reaction is performed at 600 ° C.
It has to be performed at a relatively high temperature, which is not suitable for purifying exhaust gas from automobiles.
【０００９】さらに別な方法として、燃焼排ガスの高温
部に還元剤として石油系燃料を単独あるいは燃焼排ガス
の一部または空気と燃焼排ガスの一部とで希釈して添加
し、その下流に空気を添加して燃焼排ガス中のNOx を低
減するにあたり、比（燃焼排ガス中の残存酸素量／添加
する石油系燃料の完全燃焼に要する酸素量）が特定の範
囲内となるように、メタン、プロパン、ガソリン、灯
油、ナフサ、重油等の石油系燃料を複数段に分けて添加
し、NOx を低減する方法がある（特開昭５４−７９１６
１号）。As a further method, a petroleum-based fuel as a reducing agent is added to a high temperature portion of combustion exhaust gas alone or diluted with a part of combustion exhaust gas or diluted with air and a part of combustion exhaust gas, and air is added downstream thereof. To reduce NOx in flue gas by adding methane, propane, methane, propane, so that the ratio (residual oxygen amount in flue gas / oxygen amount required for complete combustion of petroleum-based fuel to be added) falls within a specific range. There is a method for reducing NOx by adding petroleum-based fuel such as gasoline, kerosene, naphtha, and heavy oil in multiple stages to reduce NOx (Japanese Patent Laid-Open No. 54-7916).
No. 1).
【００１０】しかしながら、この方法では、還元剤とNO
x とを反応させる部位を１０００℃以上に保持しないと
効果的なNOx の除去ができず、これも自動車の排ガス浄
化には適さない。However, in this method, the reducing agent and NO
Unless the site that reacts with x is kept at 1000 ° C or higher, NOx cannot be effectively removed, which is also not suitable for exhaust gas purification of automobiles.
【００１１】したがって本発明の目的は、過剰の酸素を
含有する（ここで、「過剰の酸素を含有する」とは、そ
の排ガス中に含まれる一酸化炭素、水素、炭化水素等の
未燃焼成分を燃焼するのに必要な理論酸素量より多い酸
素を含むことを意味する）排ガスに含まれるNOx を、実
際の自動車の排ガス温度程度の比較的低温（３００〜５
５０℃程度）で、効果的に除去することができる排ガス
浄化方法を提供することである。Therefore, an object of the present invention is to contain excess oxygen (here, "containing excess oxygen" means unburned components such as carbon monoxide, hydrogen, hydrocarbons contained in the exhaust gas. NOx contained in exhaust gas is relatively low (300 to 5) that is equivalent to the exhaust gas temperature of an actual automobile.
It is an object of the present invention to provide an exhaust gas purification method that can be effectively removed at about 50 ° C.
【００１２】[0012]
【課題を解決するための手段】上記課題に鑑み鋭意研究
の結果、本発明者は、耐熱性を有する基体の表面に、特
定量の銀又は銀酸化物を担持した多孔質のセラミック層
を形成してなる排ガス浄化材を排ガス導管の途中に設置
し、液状炭化水素を排ガス浄化材の上流側に噴霧して微
粒子の状態で排ガスに混入してやれば、特に排ガス浄化
材の周辺部分を加熱してやらなくても、導入した炭化水
素により排ガス中のNOx を効率良く還元除去することが
できることを発見し、本発明を完成した。As a result of earnest research in view of the above problems, the present inventors have formed a porous ceramic layer carrying a specific amount of silver or silver oxide on the surface of a substrate having heat resistance. If the exhaust gas purifying material is installed in the middle of the exhaust gas conduit, and liquid hydrocarbons are sprayed on the upstream side of the exhaust gas purifying material and mixed into the exhaust gas in the form of fine particles, it is not necessary to heat the peripheral portion of the exhaust gas purifying material. Even so, it was discovered that NOx in exhaust gas can be efficiently reduced and removed by the introduced hydrocarbon, and the present invention was completed.
【００１３】すなわち、本発明の排ガス浄化方法は、排
ガスの流路の途中に、耐熱性を有する基体の表面上に銀
又は銀酸化物を含有する多孔質のセラミック層を形成し
てなる排ガス浄化材を設置し、前記排ガス浄化材の上流
側で前記排ガス中に沸点が１６０〜３４０℃の液状炭化
水素を噴霧し、微粒化されガス化された前記炭化水素を
還元剤として作用させて前記排ガス中の窒素酸化物を還
元除去する方法であって、前記多孔質のセラミック層に
担持された銀又は銀酸化物の量が、前記多孔質のセラミ
ック層の０．１〜５重量％（元素換算値）であることを
特徴とする。That is, the exhaust gas purification method of the present invention is an exhaust gas purification method in which a porous ceramic layer containing silver or silver oxide is formed on the surface of a heat-resistant substrate in the middle of the exhaust gas flow path. Material is installed, liquid hydrocarbon having a boiling point of 160 to 340 ° C. is sprayed into the exhaust gas on the upstream side of the exhaust gas purifying material, and the atomized and gasified hydrocarbon acts as a reducing agent to generate the exhaust gas. A method for reducing and removing nitrogen oxides therein, wherein the amount of silver or silver oxide supported on the porous ceramic layer is 0.1 to 5% by weight of the porous ceramic layer (element conversion. Value).
【００１４】[0014]
【実施例】以下、本発明を詳細に説明する。The present invention will be described in detail below.
【００１５】まず、本発明で用いる排ガス浄化材につい
て説明する。本発明では、耐熱性、耐熱衝撃性等に優れ
た排ガス浄化材基体の表面に、特定量の銀又は銀酸化物
を担持したセラミック層を形成してなる浄化材を用い、
これを排ガスの流路の途中に設置するが、この浄化材の
基体としては、これまでに排ガスコンバータとして提案
されてきたセラミック製の多孔質の成形体、又は金属製
の多孔質の成形体を用いることができる。耐久性、浄化
特性等の点からセラミック製の多孔質の成形体を用いる
のがよい。また上記の成形体の他に、多孔質のペレット
状物又は粒状物をケーシングに充填したものや、耐熱性
の繊維状物をケーシングに充填したものを、上記した成
形体と同様に排ガス浄化材の基体として用いることもで
きる。First, the exhaust gas purifying material used in the present invention will be described. In the present invention, on the surface of the exhaust gas purifying material substrate having excellent heat resistance, thermal shock resistance, etc., a purifying material formed by forming a ceramic layer carrying a specific amount of silver or silver oxide,
This is installed in the middle of the flow path of the exhaust gas, and as the substrate of this purification material, a ceramic porous molded body or a metal porous molded body that has been proposed as an exhaust gas converter has been proposed so far. Can be used. From the viewpoint of durability and purification characteristics, it is preferable to use a porous molded body made of ceramic. In addition to the above-mentioned molded body, a porous pellet-shaped material or a granular material filled in a casing, or a heat-resistant fibrous material filled in a casing, an exhaust gas purifying material similar to the above-described molded body. It can also be used as a substrate.
【００１６】基体を形成するセラミックスとしては、ア
ルミナ、シリカ、ジルコニア、シリカ−アルミナ、アル
ミナ−ジルコニア、アルミナ−チタニア、シリカ−チタ
ニア、シリカ−ジルコニア、チタニア−ジルコニア、ム
ライト、コージェライト等が挙げられる。好ましいセラ
ミック材としてはコージェライト、ムライト、アルミナ
及びその複合体等が挙げられる。Examples of the ceramics forming the substrate include alumina, silica, zirconia, silica-alumina, alumina-zirconia, alumina-titania, silica-titania, silica-zirconia, titania-zirconia, mullite and cordierite. Preferred ceramic materials include cordierite, mullite, alumina and composites thereof.
【００１７】また、上述した材料からなる基体の表面に
設けられる多孔質のセラミック層としては、γ−アルミ
ナ、又はチタニア−アルミナ、シリカ−アルミナ、ジル
コニア−アルミナ等のアルミナ系複合酸化物が挙げられ
る。特に好ましくは、γ−アルミナを用いる。As the porous ceramic layer provided on the surface of the substrate made of the above-mentioned materials, γ-alumina or alumina-based composite oxide such as titania-alumina, silica-alumina or zirconia-alumina can be used. . Particularly preferably, γ-alumina is used.
【００１８】排ガスが浄化材内を通過する際に、排ガス
中のNOx と排ガス中に微粒状に添加されガス化した液状
炭化水素とが反応し、NOx が還元除去されるが、この還
元反応を効果的に進行させるためには、浄化材としてガ
スとの接触面積が大きいものを用いるのがよい。When the exhaust gas passes through the purification material, NOx in the exhaust gas reacts with the liquid hydrocarbon that is finely added to the exhaust gas and gasified, and NOx is reduced and removed. In order to effectively proceed, it is preferable to use a cleaning material having a large contact area with the gas.
【００１９】多孔質で表面積の大きいセラミック層を成
形体の表面上に形成し、このセラミック層に良好な分散
状態で銀又は銀酸化物を担持することにより、排ガス中
のNOx 、酸素と、排ガス中に添加した炭化水素とを効果
的に反応させることができるようになる。また、その反
応温度領域も広くなり、良好なNOx の浄化が可能とな
る。By forming a porous ceramic layer having a large surface area on the surface of the molded body and carrying silver or silver oxide in a good dispersed state on this ceramic layer, NOx and oxygen in the exhaust gas and exhaust gas It becomes possible to effectively react with the hydrocarbon added therein. In addition, the reaction temperature range is widened, and good NOx purification is possible.
【００２０】なお、排ガス浄化材として、圧力損失が許
容範囲内にあることも重要であり、この点を考慮して、
成形体の表面上に設ける多孔質のセラミック層の量、成
形体自体の空孔率、密度等を適宜設定する。As an exhaust gas purifying material, it is important that the pressure loss is within the allowable range. Considering this point,
The amount of the porous ceramic layer provided on the surface of the molded body, the porosity of the molded body itself, the density and the like are appropriately set.
【００２１】上記した多孔質のセラミック層に担持され
る銀又は銀酸化物の量は、多孔質のセラミック層に対し
て０．１〜５重量％（元素換算値）とする。銀又は銀酸
化物の担持量が０．１重量％未満では銀を担持した効果
が顕著とはならず、NOx の浄化率の向上がみられない。
一方、多孔質のセラミック層の５重量％を超える量の銀
又は銀酸化物を担持すると、NOx の除去性能が低下す
る。好ましくは銀又は銀酸化物の担持量を０．５〜４重
量％とする。The amount of silver or silver oxide supported on the above-mentioned porous ceramic layer is 0.1 to 5% by weight (element conversion value) with respect to the porous ceramic layer. When the amount of silver or silver oxide supported is less than 0.1% by weight, the effect of supporting silver is not remarkable, and the NOx purification rate is not improved.
On the other hand, when an amount of silver or silver oxide that exceeds 5% by weight of the porous ceramic layer is supported, the NOx removal performance deteriorates. The supported amount of silver or silver oxide is preferably 0.5 to 4% by weight.
【００２２】上述した浄化材を用いると、３００〜５５
０℃の温度範囲及び広範囲の酸素濃度下で、液状炭化水
素、酸素、及びNOx 間の反応を促進し、効果的なNOx の
低減を行うことができる。When the above-mentioned purification material is used, it is 300 to 55.
In the temperature range of 0 ° C. and under a wide range of oxygen concentration, the reaction between liquid hydrocarbon, oxygen and NOx can be promoted to effectively reduce NOx.
【００２３】成形体の表面上に多孔質セラミック層を形
成する方法にはいくつか考えられるが、多孔質のセラミ
ック成形体を用いる場合、公知のウォッシュコート法や
ゾル−ゲル法により銀の担体層となる多孔質セラミック
層を形成するのがよい。There are several possible methods for forming a porous ceramic layer on the surface of the molded body. When a porous ceramic molded body is used, a silver carrier layer is formed by a known washcoat method or sol-gel method. It is preferable to form a porous ceramic layer that becomes
【００２４】ウォッシュコート法は、多孔質セラミック
層形成用のセラミック粉末のスラリー中に成形体を浸漬
し、乾燥することにより成形体上に担体層（多孔質セラ
ミック層）を形成する方法である。この方法により銀を
担持する場合、（イ）先ず多孔質セラミック層をウォッ
シュコート法により成形体上に形成し、その後、公知の
含浸法や沈澱法等により担体層に銀を担持する方法や、
（ロ）あらかじめ含浸法や沈澱法等により銀又は銀酸化
物を担持しておいたセラミックス粉末等を用いてウォッ
シュコートを行い、成形体上に銀又は銀酸化物を担持し
た多孔質セラミック層を形成する方法が採用できる。こ
の後者の方法によれば、一回の工程で銀又は銀酸化物を
有する担体層を形成することができる。The wash coating method is a method of forming a carrier layer (porous ceramic layer) on a molded body by immersing the molded body in a slurry of ceramic powder for forming a porous ceramic layer and drying it. In the case of supporting silver by this method, (a) first, a porous ceramic layer is formed on a molded body by a wash coating method, and thereafter, a method of supporting silver on the carrier layer by a known impregnation method or precipitation method, or
(B) Wash-coating is performed using a ceramic powder or the like on which silver or silver oxide is previously supported by an impregnation method or a precipitation method to form a porous ceramic layer supporting silver or silver oxide on the molded body. The forming method can be adopted. According to this latter method, the carrier layer containing silver or silver oxide can be formed in one step.
【００２５】また、ゾル−ゲル法による銀又は銀酸化物
の担持には以下の２通り方法がある。第一の方法は、多
孔質セラミック層を形成する金属の有機塩（例えばアル
コキシド）を加水分解し、得られたゾルを成形体にコー
ティングし、水蒸気等との接触によりコロイド粒子の膜
を生成させた後、乾燥、焼成して多孔質セラミック層を
成形体上に形成し、最後に銀又は銀酸化物の担持を行う
方法である。例えば、多孔質セラミック層をアルミナ
（Al2 Ｏ3 ）から形成し、これに銀又は銀酸化物を担持
させる場合、まずアルミニウムのアルコキシドのアルコ
ール溶液に、CH3 COOH、HNＯ3 、ＨCl等の酸を加えたコ
ーティング液を生成する。このコーティング液に成形体
を浸漬し、引き上げた後、水蒸気あるいは水と反応させ
てゲル化を行う。次いで、成形体を乾燥、焼成すれば、
成形体の空孔表面にアルミナの膜が形成される。次に、
銀の塩、例えば硝酸銀などの水溶液を多孔質セラミック
層に含浸して、再び乾燥、焼成し、銀の担持を行う。There are the following two methods for supporting silver or silver oxide by the sol-gel method. The first method is to hydrolyze an organic salt (for example, an alkoxide) of a metal forming a porous ceramic layer, coat the obtained sol on a molded body, and form a film of colloidal particles by contact with steam or the like. After that, it is dried and fired to form a porous ceramic layer on the molded body, and finally silver or silver oxide is supported. For example, when the porous ceramic layer is formed of alumina (Al 2 O 3 ) and silver or silver oxide is supported on the porous ceramic layer, first, an alcohol solution of aluminum alkoxide is added with an acid such as CH 3 COOH, HNO 3 , or HCl. To produce a coating liquid. The molded body is dipped in this coating solution, pulled up, and then reacted with water vapor or water to cause gelation. Next, if the molded body is dried and fired,
An alumina film is formed on the surface of the pores of the molded body. next,
The porous ceramic layer is impregnated with an aqueous solution of a silver salt, such as silver nitrate, and dried and fired again to carry silver.
【００２６】第二の方法は、多孔質セラミック層と銀又
は銀酸化物とを同時に成形体にコーティングする方法で
ある。例えば、まずAlアルコキシドのアルコール溶液に
HNＯ3 等の酸と、さらに銀の塩の水溶液とを加えて、コ
ーティング液を生成する。次いで、そのコーティング液
に成形体を浸漬した後、水蒸気あるいは水と反応させて
ゾル化、さらにはゲル化を行う。その後、成形体を乾
燥、焼成し、銀を担持したアルミナからなるコーティン
グ層を形成する。The second method is a method in which a porous ceramic layer and silver or silver oxide are simultaneously coated on a molded body. For example, first add Al alkoxide alcohol solution
An acid such as HNO 3 and an aqueous solution of a silver salt are added to form a coating solution. Next, after the molded body is immersed in the coating liquid, it is reacted with water vapor or water to form a sol and further gelate. Then, the molded body is dried and fired to form a coating layer made of alumina carrying silver.
【００２７】上記のいずれのゾル−ゲル法においても、
銀の塩としては水に溶解するものであればよく、硝酸銀
などを用いることができる。また、アルコキシドのアル
コール溶液中に銀の塩を均一に分散させることを目的
に、エチレングリコール等の分散剤を添加することもで
きる。In any of the above sol-gel methods,
Any silver salt may be used as long as it can be dissolved in water, and silver nitrate or the like can be used. Further, a dispersant such as ethylene glycol may be added for the purpose of uniformly dispersing the silver salt in the alcohol solution of the alkoxide.
【００２８】また、酸はゲル化の際の加水分解反応の触
媒として添加するものである。しかし、酸の代わりにア
ルカリを添加しても、加水分解反応を促進することがで
きる。The acid is added as a catalyst for the hydrolysis reaction during gelation. However, the hydrolysis reaction can be promoted by adding an alkali instead of the acid.
【００２９】焼成については、真空中、窒素ガス雰囲気
下又は水素ガス流通下で行うと銀又は銀酸化物のシンタ
リングを防止でき、空気中で焼成してなる浄化材より良
好なNOx 浄化特性を有する浄化材とすることができる。
なお、焼成温度は１００〜５００℃とし、段階的に昇温
するのが好ましい。その後、酸素を含むガス流通下、５
００℃で焼成するのがよい。このようにして担持した銀
は、排ガスの温度により金属又は酸化物の状態で浄化材
中に存在する。When firing is performed in a vacuum, in a nitrogen gas atmosphere or in a hydrogen gas flow, sintering of silver or silver oxide can be prevented, and NOx purification characteristics better than those of a purification material obtained by firing in air are obtained. It can be used as a purifying material.
The firing temperature is preferably 100 to 500 ° C., and the temperature is preferably raised stepwise. Then, under gas flow containing oxygen, 5
Baking at 00 ° C is preferable. The silver thus supported is present in the purifying material in a metal or oxide state depending on the temperature of the exhaust gas.
【００３０】ゾル−ゲル法によれば、成形体中に銀又は
銀酸化物を極めて均一に担持させることが可能であり、
従って、銀又は銀酸化物の触媒としての活性が高まり、
排ガス浄化能が向上する。According to the sol-gel method, it is possible to support silver or silver oxide in the molded body extremely uniformly,
Therefore, the activity of silver or silver oxide as a catalyst is increased,
Exhaust gas purification performance is improved.
【００３１】本発明の方法では、上述の排ガス浄化材を
排ガス導管の途中に設置し、この浄化材の上流側に液状
炭化水素を添加するが、本発明における液状炭化水素と
は、標準状態で液体状態の炭化水素であり、具体的に
は、軽油、セタン、ヘプタン、灯油等が挙げられる。好
ましくは、沸点が１６０〜３４０℃となる液状炭化水素
を用いる。実用性等を考えると、特に軽油を用いるのが
よい。In the method of the present invention, the above-mentioned exhaust gas purifying material is installed in the middle of the exhaust gas conduit and liquid hydrocarbon is added to the upstream side of this purifying material. The liquid hydrocarbon in the present invention is in a standard state. It is a hydrocarbon in a liquid state, and specific examples thereof include light oil, cetane, heptane, and kerosene. A liquid hydrocarbon having a boiling point of 160 to 340 ° C. is preferably used. Considering practicality, it is particularly preferable to use light oil.
【００３２】液状炭化水素の添加量は、排ガス中に含ま
れるNOx 量に合わせて適宜調節するのがよい。具体的に
は、排ガス中に含まれる窒素酸化物の量との重量比（液
状炭化水素の重量／排ガス中のNOx の重量）が０．２〜
３の範囲となるように設定するのが好ましい。この比が
０．２未満では良好なNOx の除去が行えず、また３を超
すと未反応の液状炭化水素が排ガス中に残り、二次公害
を生むことになる。The amount of liquid hydrocarbon added is preferably adjusted appropriately according to the amount of NOx contained in the exhaust gas. Specifically, the weight ratio to the amount of nitrogen oxides contained in the exhaust gas (weight of liquid hydrocarbon / weight of NOx in exhaust gas) is 0.2 to
It is preferable to set it within the range of 3. If this ratio is less than 0.2, good NOx cannot be removed, and if it exceeds 3, unreacted liquid hydrocarbons remain in the exhaust gas, resulting in secondary pollution.
【００３３】排ガス浄化材を通過する排ガスの温度（実
際には排ガス浄化材の上流側端部近傍の温度を測定する
ことで代用できる）は、用いる液状炭化水素（の沸点）
により多少変更する必要があるが、少なくとも３００〜
５５０℃に保持するのがよい。この温度範囲より下回る
と、NOx の効果的な還元が得られない。また、この温度
範囲を超える高温とすると、添加した液状炭化水素自体
の燃焼や液状炭化水素の縮重合反応が優先することにな
るので、やはりNOx の低減率が低下する。軽油などの比
較的高沸点の液状炭化水素を用いる場合には、排ガス浄
化装置内の排ガス温度を３５０〜５００℃とするのがよ
い。The temperature of the exhaust gas passing through the exhaust gas purifying material (actually, it can be substituted by measuring the temperature in the vicinity of the upstream end of the exhaust gas purifying material) is (the boiling point of) the liquid hydrocarbon used.
It is necessary to change it a little, but at least 300-
It is better to keep it at 550 ° C. Below this temperature range, effective reduction of NOx cannot be obtained. Also, if the temperature exceeds this temperature range, combustion of the added liquid hydrocarbon itself and polycondensation reaction of the liquid hydrocarbon are prioritized, so that the NOx reduction rate is also lowered. When a liquid hydrocarbon having a relatively high boiling point such as light oil is used, the exhaust gas temperature in the exhaust gas purifying apparatus is preferably 350 to 500 ° C.
【００３４】ところで、実際の自動車の排ガス温度は、
エンジンの運転状況によって刻々変化する。そこでNOx
の浄化を確実にするためには、排ガス温度を上述の温度
範囲内に制御するのがよい。その制御の一例として、た
とえば以下のような方法がある。すなわち、排ガス浄化
材より上流側に排ガス流量を調節する弁を設け、排ガス
浄化材近傍の排ガス温度（又は排ガス浄化材内の温度）
をモニターしておき、排ガス温度が上記範囲を下回った
時点で弁を絞り排ガス温度を上げる。なお、排ガス温度
を下げる場合には、上述の操作の反対の操作を行えばよ
い。By the way, the actual exhaust gas temperature of an automobile is
It changes every moment depending on the operating condition of the engine. So NOx
In order to ensure the purification of the above, it is preferable to control the exhaust gas temperature within the above temperature range. As an example of the control, there is the following method. That is, a valve for adjusting the flow rate of exhaust gas is provided upstream of the exhaust gas purification material, and the exhaust gas temperature near the exhaust gas purification material (or the temperature inside the exhaust gas purification material)
Is monitored, and when the exhaust gas temperature falls below the above range, the valve is throttled to raise the exhaust gas temperature. When lowering the exhaust gas temperature, the opposite operation to the above operation may be performed.
【００３５】本発明の方法を以下の具体的実施例により
さらに詳細に説明するが、本発明はこれに限定されな
い。The method of the present invention will be explained in more detail by the following specific examples, but the present invention is not limited thereto.
【００３６】実施例１ 市販のペレット状のγ−アルミナ１２ｇ（直径1.5mm 、
長さ約６mm）を硝酸銀水溶液（硝酸銀濃度０．０２ｇ／
ml）に浸漬し、７０℃で乾燥後、５容量％の水素を含む
窒素気流下、１５０℃、２００℃、３００℃、４００
℃、及び５００℃で各２時間ずつ焼成後、酸素を１０％
含有する窒素気流下、５００℃で２時間焼成し、ペレッ
ト状のγ−アルミナに対して１重量％の銀を担持した浄
化材を得た。 Example 1 12 g of commercially available pelletized γ-alumina (diameter 1.5 mm,
Approximately 6 mm in length is a silver nitrate aqueous solution (silver nitrate concentration 0.02 g /
ml), dried at 70 ° C., and then in a nitrogen stream containing 5% by volume of hydrogen, 150 ° C., 200 ° C., 300 ° C., 400
After firing at ℃ and 500 ℃ for 2 hours each, oxygen 10%
It was calcined at 500 ° C. for 2 hours in a nitrogen stream containing it to obtain a purification material in which 1% by weight of silver was supported on γ-alumina in pellet form.
【００３７】この浄化材を反応管に充填し、表１に示す
組成の模擬ディーゼルエンジン排ガスを毎分２リットル
（標準状態換算）の流速で流すとともに、この排ガス中
に、軽油量／排ガス中のＮＯｘ量の重量比が２となるよ
うに、軽油を加え（軽油添加量８．０４ｍｇ／分）、ま
た反応管内の排ガス温度を３５０〜５５０℃の範囲に保
ち、ガス化した軽油と窒素酸化物とを反応させた。The purifying material was filled in a reaction tube, and a simulated diesel engine exhaust gas having the composition shown in Table 1 was flowed at a flow rate of 2 liters per minute (standard state conversion). Light oil was added so that the weight ratio of NOx amount was 2 (light oil addition amount was 8.04 mg / min), and the exhaust gas temperature in the reaction tube was kept in the range of 350 to 550 ° C. to gasify light oil and nitrogen oxidation. Reacted with things.
【００３８】反応管通過後のガス中の窒素酸化物の濃度
を化学発光式窒素酸化物分析計により測定し、窒素酸化
物の除去率を求めた。結果を表２に示す。The nitrogen oxide concentration in the gas after passing through the reaction tube was measured by a chemiluminescence type nitrogen oxide analyzer to determine the nitrogen oxide removal rate. The results are shown in Table 2.
【００３９】 表１ 成分 濃度 酸素 １０容量％ 一酸化窒素 １５００ｐｐｍ 水分 １０容量％ 窒素 残部 〔軽油 ８．０４ｍｇ／分（窒素酸化物の２倍の重量）〕Table 1 Component Concentration Oxygen 10% by volume Nitric oxide 1500 ppm Moisture 10% by volume Nitrogen balance [light oil 8.04 mg / min (twice the weight of nitrogen oxides)]
【００４０】比較例１、２ 比較のために、銀又は銀酸化物を担持していない他は実
施例１と同様とした浄化材を用いた以外は、実施例１と
同様にして窒素酸化物の除去試験（比較例１）を行っ
た。 Comparative Examples 1 and 2 Nitrogen oxides were prepared in the same manner as in Example 1 except that a purifying material similar to that in Example 1 was used except that silver or silver oxide was not supported. Was removed (Comparative Example 1).
【００４１】また、実施例１で用いたペレット状のγ−
アルミナと同一形状のTiＯ2 ペレット（密度１g/cm3 ）
を浄化材として用いた以外は実施例１と同様にして、窒
素酸化物の除去試験を行った（比較例２）。結果をとも
に表２に示す。Further, the pelletized γ-type used in Example 1 was used.
TiO 2 pellets with the same shape as alumina (density 1 g / cm 3 )
A nitrogen oxide removal test was conducted in the same manner as in Example 1 except that was used as a purification material (Comparative Example 2). The results are shown in Table 2.
【００４２】 [0042]
【００４３】表２からわかるように、実施例１において
は、３５０〜４５０℃の排ガス温度領域で効果的に排ガ
ス中の窒素酸化物を除去した。As can be seen from Table 2, in Example 1, the nitrogen oxides in the exhaust gas were effectively removed in the exhaust gas temperature range of 350 to 450 ° C.
【００４４】[0044]
【発明の効果】以上詳述したように、本発明の方法によ
れば、過剰の酸素を含む排ガス中の窒素酸化物を効率良
く除去することができる。また、本発明の方法では、排
ガス中に水分が１０％程度含まれた場合でも良好な窒素
酸化物の除去を行うことができる。さらに、窒素酸化物
の除去温度（排ガス温度）も３００〜５５０℃と、これ
までの除去方法に比してより低温とすることができる。As described in detail above, according to the method of the present invention, nitrogen oxides in exhaust gas containing excess oxygen can be efficiently removed. In addition, according to the method of the present invention, good removal of nitrogen oxides can be performed even when the exhaust gas contains about 10% of water. Furthermore, the nitrogen oxide removal temperature (exhaust gas temperature) can be set to 300 to 550 ° C., which is lower than the conventional removal methods.
【００４５】本発明の排ガス浄化方法は、各種燃焼機、
ディーゼルエンジンやガソリンエンジン等の排ガスに含
まれる窒素酸化物の除去に広く利用することができる。The exhaust gas purification method of the present invention is applied to various combustors,
It can be widely used for removing nitrogen oxides contained in exhaust gas from diesel engines and gasoline engines.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 吉田 清英 埼玉県熊谷市熊谷810番地 株式会社リケ ン熊谷事業所内 審査官 大熊 幸治 (56)参考文献 特開 平４−281844（ＪＰ，Ａ) 特開 平４−354536（ＪＰ，Ａ) 特開 平２−59047（ＪＰ，Ａ) 特公 昭55−17618（ＪＰ，Ｂ２) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyohide Yoshida 810 Kumagaya, Kumagaya, Saitama Kenji Okuma, Examiner, Rikuma Kumagaya Works Co., Ltd. (56) Reference Japanese Patent Laid-Open No. 4-281844 (JP, A) Kaihei 4-354536 (JP, A) JP-A-2-59047 (JP, A) JP-B-55-17618 (JP, B2)
Claims (3)
基体の表面上に銀又は銀酸化物を担持した多孔質のセラ
ミック層を形成してなる排ガス浄化材を設置し、前記排
ガス浄化材の上流側で前記排ガス中に沸点が１６０〜３
４０℃の液状炭化水素を噴霧し、微粒化されガス化され
た前記炭化水素を還元剤として作用させて前記排ガス中
の窒素酸化物を還元除去する排ガス浄化方法であって、
前記多孔質のセラミック層に担持された銀又は銀酸化物
の量が、前記多孔質のセラミック層の０．１〜５重量％
（元素換算値）であることを特徴とする排ガス浄化方
法。1. An exhaust gas purifying material comprising a porous ceramic layer supporting silver or silver oxide formed on the surface of a heat-resistant substrate in the middle of an exhaust gas flow path, the exhaust gas purifying material being provided. On the upstream side of the material, the boiling point in the exhaust gas is 160 to 3
A method for purifying exhaust gas, comprising spraying liquid hydrocarbon at 40 ° C., causing the atomized and gasified hydrocarbon to act as a reducing agent to reduce and remove nitrogen oxides in the exhaust gas,
The amount of silver or silver oxide supported on the porous ceramic layer is 0.1 to 5% by weight of the porous ceramic layer.
A method for purifying exhaust gas, which is (elemental conversion value).
て、前記多孔質のセラミック層が、γ−アルミナ、又は
アルミナ系複合酸化物であることを特徴とする排ガス浄
化方法。2. The exhaust gas purification method according to claim 1, wherein the porous ceramic layer is γ-alumina or an alumina-based composite oxide.
において、前記液状炭化水素として軽油を用い、前記排
ガス浄化材近傍における排ガスの温度を３５０〜５００
℃に保つことを特徴とする排ガス浄化方法。3. The exhaust gas purification method according to claim 1, wherein light oil is used as the liquid hydrocarbon, and the temperature of the exhaust gas in the vicinity of the exhaust gas purification material is 350 to 500.
A method for purifying exhaust gas, which is characterized in that the temperature is maintained at ℃.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3280825A JPH0696094B2 (en) | 1991-09-30 | 1991-09-30 | Exhaust gas purification method |
| EP92306728A EP0526099B1 (en) | 1991-07-23 | 1992-07-23 | Exhaust gas cleaner |
| EP95201503A EP0679427A1 (en) | 1991-07-23 | 1992-07-23 | Exhaust gas cleaner |
| DE69222488T DE69222488T2 (en) | 1991-07-23 | 1992-07-23 | Exhaust gas cleaner |
| US08/428,635 US5534237A (en) | 1991-07-23 | 1995-04-25 | Method of cleaning an exhaust gas and exhaust gas cleaner therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3280825A JPH0696094B2 (en) | 1991-09-30 | 1991-09-30 | Exhaust gas purification method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0592125A JPH0592125A (en) | 1993-04-16 |
| JPH0696094B2 true JPH0696094B2 (en) | 1994-11-30 |
Family
ID=17630512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3280825A Expired - Lifetime JPH0696094B2 (en) | 1991-07-23 | 1991-09-30 | Exhaust gas purification method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0696094B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0605251A1 (en) * | 1992-12-28 | 1994-07-06 | Kabushiki Kaisha Riken | Exhaust gas cleaner |
| JP2631814B2 (en) * | 1994-04-20 | 1997-07-16 | 株式会社リケン | Exhaust gas purifying material and exhaust gas purifying method |
| EP0710499A3 (en) * | 1994-11-04 | 1997-05-21 | Agency Ind Science Techn | Exhaust gas cleaner and method for cleaning exhaust gas |
| JP3495832B2 (en) * | 1995-11-24 | 2004-02-09 | 財団法人石油産業活性化センター | Method for catalytic reduction of nitrogen oxides |
| US6309617B1 (en) * | 1997-07-10 | 2001-10-30 | Dornier Gmbh | Solid for storing/releasing nitrogen oxides as well as nitrogen oxide storage catalyst |
| US7374728B2 (en) | 2003-03-06 | 2008-05-20 | Honda Motor Co., Ltd. | Exhaust gas purification system |
| US7043902B2 (en) | 2003-03-07 | 2006-05-16 | Honda Motor Co., Ltd. | Exhaust gas purification system |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5517618A (en) * | 1978-07-21 | 1980-02-07 | Hitachi Ltd | Vacuum pump sealed up against water |
| US4912077A (en) * | 1988-07-15 | 1990-03-27 | Corning Incorporated | Catalytically active materials and method for their preparation |
| JP2634251B2 (en) * | 1989-09-04 | 1997-07-23 | 三菱重工業株式会社 | Catalytic cracking denitration method |
| JP2801423B2 (en) * | 1991-03-08 | 1998-09-21 | 住友金属鉱山 株式会社 | Nitrogen oxide purification catalyst |
| JPH04354536A (en) * | 1991-05-29 | 1992-12-08 | Asahi Glass Co Ltd | Catalyst for decomposition of nitrogen oxide and method for decomposing nitrogen oxide |
| JPH05212246A (en) * | 1991-08-28 | 1993-08-24 | Osaka Gas Co Ltd | Method for purifying nitrogen oxide in waste gas |
-
1991
- 1991-09-30 JP JP3280825A patent/JPH0696094B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0592125A (en) | 1993-04-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3440290B2 (en) | Exhaust gas purification method | |
| US5885923A (en) | Exhaust gas cleaner | |
| US5772973A (en) | Exhaust gas cleaner and method for removing nitrogen oxides | |
| US5670443A (en) | Exhaust gas cleaner and method for cleaning exhaust gas | |
| JPH0696094B2 (en) | Exhaust gas purification method | |
| EP0682975A1 (en) | Device and method for cleaning exhaust gas | |
| JPH0824583A (en) | Exhaust gas purifying material and method for purifying exhaust gas | |
| EP0605237A1 (en) | Exhaust gas cleaner | |
| JP2587000B2 (en) | Exhaust gas purifying material and exhaust gas purifying method | |
| JPH07275709A (en) | Material and method for purifying exhaust gas | |
| JPH06142523A (en) | Waste gas purifying material and waste gas purifying method | |
| JP3854325B2 (en) | Exhaust gas purification material and exhaust gas purification method | |
| JPH10328567A (en) | Waste gas purifying material and waste gas purifying method | |
| JPH08168650A (en) | Material and method for purifying exhaust gas | |
| JPH09248459A (en) | Material and method for exhaust gas-purifying | |
| JPH05237336A (en) | Method and device for purifying exhaust gas | |
| JPH09262439A (en) | Nitrogen oxide removing material and removing method of nitrogen oxide | |
| JP3530214B2 (en) | Exhaust gas purification material and exhaust gas purification method | |
| JPH0857263A (en) | Exhaust gas purifying material and method therefor | |
| JPH0975739A (en) | Waste gas purification material and method for purifying waste gas | |
| JPH05237389A (en) | Purifier of exhaust gas and method for purification of exhaust gas | |
| JPH0824646A (en) | Material and method for purifying exhaust gas | |
| JPH09313892A (en) | Cleaning method of exhaust gas | |
| JPH05146643A (en) | Purification of exhaust gas | |
| JPH0852327A (en) | Exhaust gas purifying material and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |