JP2930975B2 - Method for producing combustion catalyst - Google Patents
Method for producing combustion catalystInfo
- Publication number
- JP2930975B2 JP2930975B2 JP1184269A JP18426989A JP2930975B2 JP 2930975 B2 JP2930975 B2 JP 2930975B2 JP 1184269 A JP1184269 A JP 1184269A JP 18426989 A JP18426989 A JP 18426989A JP 2930975 B2 JP2930975 B2 JP 2930975B2
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- alumina
- lanthanum
- component
- noble metal
- 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 - Fee Related
Links
- 239000003054 catalyst Substances 0.000 title claims description 75
- 238000002485 combustion reaction Methods 0.000 title claims description 11
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 229910052746 lanthanum Inorganic materials 0.000 claims description 41
- -1 lanthanum aluminate Chemical class 0.000 claims description 39
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 33
- 229910000510 noble metal Inorganic materials 0.000 claims description 27
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 27
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 13
- 229910052697 platinum Inorganic materials 0.000 claims description 12
- 150000002604 lanthanum compounds Chemical class 0.000 claims description 9
- 230000008093 supporting effect Effects 0.000 claims description 9
- 229910052763 palladium Inorganic materials 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 description 16
- 239000002245 particle Substances 0.000 description 12
- 239000007789 gas Substances 0.000 description 9
- 239000000843 powder Substances 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- RBAKORNXYLGSJB-UHFFFAOYSA-N azane;platinum(2+);dinitrate Chemical compound N.N.N.N.[Pt+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O RBAKORNXYLGSJB-UHFFFAOYSA-N 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000001354 calcination Methods 0.000 description 4
- 239000012153 distilled water Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 4
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- 229910052761 rare earth metal Inorganic materials 0.000 description 4
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 2
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 239000003063 flame retardant Substances 0.000 description 2
- 230000001976 improved effect Effects 0.000 description 2
- 230000000977 initiatory effect Effects 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Natural products CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 1
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 1
- 229910000873 Beta-alumina solid electrolyte Inorganic materials 0.000 description 1
- 241000264877 Hippospongia communis Species 0.000 description 1
- 229910021193 La 2 O 3 Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- YKIOKAURTKXMSB-UHFFFAOYSA-N adams's catalyst Chemical compound O=[Pt]=O YKIOKAURTKXMSB-UHFFFAOYSA-N 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000007084 catalytic combustion reaction Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 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 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- JLRJWBUSTKIQQH-UHFFFAOYSA-K lanthanum(3+);triacetate Chemical compound [La+3].CC([O-])=O.CC([O-])=O.CC([O-])=O JLRJWBUSTKIQQH-UHFFFAOYSA-K 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000005297 pyrex Substances 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、自動車や各種工場から排出される一酸化炭
素、炭化水素類等の有害成分を含有する排ガスの浄化や
メタン（CH4）、プロパン（C3H8）等の難燃性燃料の燃
焼に用いる触媒に係わり、特に耐熱性と低温活性に優れ
た触媒およびその製法に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to purification of exhaust gas containing harmful components such as carbon monoxide and hydrocarbons discharged from automobiles and various factories, and purification of methane (CH 4 ), The present invention relates to a catalyst used for combustion of a flame-retardant fuel such as propane (C 3 H 8 ), and more particularly to a catalyst having excellent heat resistance and low-temperature activity and a method for producing the same.
触媒燃焼法は、自動車排ガス中の一酸化炭素、炭化水
素類の浄化、各種工場排ガス中の酢酸エチル、アルデヒ
ド類等の有害成分の浄化、あるいはメタン（CH4）、プ
ロパンガス（C3H8）等の難燃性燃料の無炎燃焼などに幅
広く用いられている。このとき用いられる触媒系は、ア
ルミナをベースとして、それに白金（Pt）、パラジウム
（Pd）等の貴金属を担持したものが主流であるが、触媒
の耐熱性が不十分なために、その使用温度を制限あるい
は制御することが必要であった。例えば、自動車排ガス
浄化用触媒としては、白金を主体として、ロジウムをそ
の1/5〜1/20程度アルミナ担体に担持した、いわゆる三
元触媒が広く用いられている。しかし、このような触媒
は、酸化雰囲気の下で600℃を超える条件で使用する
と、急激に劣化する。これは、気相中の過剰酸素が触媒
中で活性点を形成している白金（Pt）と結合して酸化白
金（PtO2）となり、これがさらにシンタリングを起こし
て巨大粒子化し触媒活性点が減少するためであるとされ
ている（特公昭63−24418号、若宮、中村、触媒、21,98
−103（1979））。また、担体側がシンタリングを起こ
すような高温域では、それに誘引されて触媒成分のシン
タリングが促進され触媒が著しい劣化を起こす、いわゆ
るEarthquake Effectも触媒の熱劣化原因の１つに考え
られている（松田、山下、触媒、29,293−298（198
7））。このような背景から、触媒の耐熱性を高めるた
めの検討が、触媒成分および担体の両面からなされてお
り、アルカリ土類元素化合物や希土類元素化合物を添加
して触媒の耐熱性を改善する方法が数多く提案されてい
る（特開昭61−28453号、特開昭61−245844号、特開昭6
2−1454号、第56回触媒討論会（Ａ）講演予稿集、4N1
7、192（1985）、特開昭61−38627号、特公昭63−24418
号、特開昭61−84636号等）。これらの方法の意図は、
アルカリ土類元素あるいは希土類の化合物を添加して、
担体であるアルミナを安定化したり、活性成分の酸素活
性化能の低下を抑制することにあるとされている。自動
車排ガス浄化用触媒においては、セリア（CeO2）を添加
して、触媒のウインドウ幅（一酸化炭素、炭化水素類お
よび窒素酸化物の同時除去率の高い空燃比領域）の拡大
および耐熱性の向上を図っているが、それはセリアの次
式に基づく酸素ストレージ能によるものと考えられてい
る（田口、触媒、29,605−609（1987））。The catalytic combustion method purifies carbon monoxide and hydrocarbons in automobile exhaust gas, purifies harmful components such as ethyl acetate and aldehyde in exhaust gas from various factories, or purifies methane (CH 4 ) and propane gas (C 3 H 8). ) Is widely used for flameless combustion of flame-retardant fuels. The catalyst system used at this time is mainly an alumina-based catalyst which carries a noble metal such as platinum (Pt) or palladium (Pd). However, since the heat resistance of the catalyst is insufficient, its operating temperature is low. Need to be limited or controlled. For example, a so-called three-way catalyst in which platinum is the main component and rhodium is supported on an alumina carrier in an amount of about 1/5 to 1/20 is widely used as a catalyst for automobile exhaust gas purification. However, such a catalyst rapidly deteriorates when used in a condition exceeding 600 ° C. in an oxidizing atmosphere. This is because excess oxygen in the gas phase combines with platinum (Pt), which forms an active site in the catalyst, to form platinum oxide (PtO 2 ), which further sinters into giant particles and turns into a catalytic active site. (Japanese Patent Publication No. 63-24418, Wakamiya, Nakamura, Catalyst, 21 , 98
−103 (1979)). Also, in a high temperature range where the carrier side causes sintering, the so-called Earthquake Effect, which is induced by the sintering and promotes the sintering of the catalyst component to cause significant deterioration of the catalyst, is also considered to be one of the causes of thermal deterioration of the catalyst. (Matsuda, Yamashita, Catalyst, 29 , 293-298 (198
7)). Against this background, studies to improve the heat resistance of the catalyst have been made from both sides of the catalyst component and the carrier, and there is a method of improving the heat resistance of the catalyst by adding an alkaline earth compound or a rare earth element compound. Many proposals have been made (JP-A-61-28453, JP-A-61-245844, JP-A-61-245844).
No. 2-1454, Proceedings of the 56th Symposium on Catalysis (A), 4N1
7, 192 (1985), JP-A-61-38627, JP-B-63-24418
No. JP-A-61-84636). The intent of these methods is
Add an alkaline earth element or rare earth compound,
It is said to stabilize alumina as a carrier and to suppress a decrease in the oxygen activating ability of the active ingredient. For automotive exhaust gas purification catalysts, ceria (CeO 2 ) is added to expand the catalyst window width (air-fuel ratio region where the simultaneous removal rate of carbon monoxide, hydrocarbons and nitrogen oxides is high) and to improve heat resistance. This is thought to be due to the oxygen storage capacity based on the following formula of ceria (Taguchi, Catalysis, 29 , 605-609 (1987)).
2CeO2→Ce2O3＋1/2O2 ……（１） 本発明者らは、酸化雰囲気で700〜1,000℃の温度域で
も劣化が少なくかつ高活性で長期間使用可能な燃焼用触
媒の開発を進める過程で、上記アルカリ土類元素あるい
は希土類元素化合物の添加効果を詳細に検討した結果、
ランタン（La）が特に効果の高い元素の１つであり、さ
らにランタン化合物の添加方法によってその効果の発現
に著しい違いのあることを見いだした。1,000℃以下の
温度条件で触媒を使用する場合、担体の耐熱性よりも触
媒成分の耐熱性が重要である。従来はランタン化合物の
添加の目的は、アルミナ担体の熱安定性を高めることに
あったが、ペロブスカイト型構造を持つランタンアルミ
ネート（LaAlO3）なる化合物を生成させ、そこに選択的
に貴金属成分を担持させると触媒成分の耐熱性も高まる
ことが明らかになった。2CeO 2 → Ce 2 O 3 + 1 / 2O 2 (1) The present inventors have developed a combustion catalyst which is less deteriorated even in a temperature range of 700 to 1,000 ° C. in an oxidizing atmosphere, has high activity, and can be used for a long time. In the process of proceeding, as a result of detailed examination of the effect of adding the alkaline earth element or rare earth compound,
Lanthanum (La) is one of the elements having a particularly high effect, and it has been found that there is a remarkable difference in the expression of the effect depending on the method of adding the lanthanum compound. When the catalyst is used under a temperature condition of 1,000 ° C. or less, the heat resistance of the catalyst component is more important than the heat resistance of the carrier. The purpose of the conventional addition of the lanthanum compound is was to increase the thermal stability of the alumina support, to produce a lanthanum aluminate (LaAlO 3) comprising a compound having a perovskite structure, there selectively precious metal component It became clear that the heat resistance of the catalyst component was increased when supported.
従来、ランタンアルミネートは、表面積が小さいの
で、触媒中に存在すると好ましくないとされており（例
えば、特開昭62−180751号）、有効であるとする提案は
あるものの（特開昭62−282640号）、それはペロブスカ
イト型構造に由来する酸素ストレージ性を期待したもの
であって触媒成分自体の耐熱性向上を直接狙ったもので
はない。従来発明の触媒では、必ずしもランタンアルミ
ネート上に活性成分が担持されず、アルカリ土類あるい
は希土類元素化合物の効果を十分発揮できなかったため
に、触媒中の高価な貴金属成分の活用が不十分であっ
た。Hitherto, lanthanum aluminate has been considered to be undesirable when present in a catalyst because of its small surface area (for example, JP-A-62-180751). No. 282640), which is expected to have an oxygen storage property derived from the perovskite structure, and is not directly aimed at improving the heat resistance of the catalyst component itself. In the catalyst of the present invention, the active component is not always supported on the lanthanum aluminate, and the effect of the alkaline earth or rare earth element compound cannot be sufficiently exerted. Therefore, the utilization of the expensive noble metal component in the catalyst is insufficient. Was.
本発明は、上記従来発明の不十分な点を改良し、担持
貴金属触媒の耐熱性向上に対するランタン化合物の添加
効果を有効に引き出して、性能の高い触媒を得るととも
に、活性成分である貴金属を十分に活用することを目的
としたものである。The present invention improves the inadequate points of the above-mentioned conventional invention, effectively extracts the effect of adding a lanthanum compound on the improvement of the heat resistance of the supported noble metal catalyst, obtains a high-performance catalyst, and sufficiently reduces the noble metal as an active component. It is intended to be used for
上記目的は、担持貴金属触媒を得るに際して、ランタ
ンアルミネートに貴金属成分を担持した後、それを耐火
性無機担体に添加してその表面積を被覆することによっ
て達成される。The above object is achieved by obtaining a supported noble metal catalyst by supporting a noble metal component on lanthanum aluminate, and then adding the noble metal component to a refractory inorganic carrier to cover the surface area thereof.
すなわち本発明は、耐火性無機担体を第一成分とし、
ランタンアルミネートを第二成分、白金およびパラジウ
ムから選ばれた一種以上の貴金属を第三成分とする燃焼
用触媒の製造方法において、予め調製されたランタンア
ルミネートに前記貴金属成分を担持し、これを第一成分
である耐火性無機担体表面に被覆することを特徴とす
る。That is, the present invention uses a refractory inorganic carrier as a first component,
Lanthanum aluminate as the second component, a method for producing a combustion catalyst having at least one noble metal selected from platinum and palladium as the third component, wherein the noble metal component is supported on a previously prepared lanthanum aluminate, It is characterized by being coated on the surface of the refractory inorganic carrier as the first component.
本発明において、ランタンアルミネートをαアルミナ
とランタン化合物との反応により調製することが好まし
い。In the present invention, lanthanum aluminate is preferably prepared by reacting α-alumina with a lanthanum compound.
従来の発明は、表面積の高いγ、θ、δといった転移
性アルミナにランタン化合物を添加した後、焼成するこ
とにより熱安定性に優れたアルミナ担体を得、次いで触
媒成分を担持するものである。この方法では、ランタン
とアルミナとの種々の反応生成物が担体内に分散して生
成するため、触媒成分である貴金属は、第１図に示した
ように、アルミナやアルミナ−ランタン反応生成物上に
非選択的に担持されてしまう。すなわち、従来触媒で
は、ランタンアルミネート上に担持された貴金属は高活
性でかつ耐熱性も高いが、それ以外の貴金属は耐熱性が
改善されておらず、触媒は700〜1,000℃の高温で長期間
使用することができなかった。In the conventional invention, an alumina carrier having excellent thermal stability is obtained by adding a lanthanum compound to a transition surface alumina having a high surface area such as γ, θ, and δ, followed by firing, and then supporting a catalyst component. In this method, since various reaction products of lanthanum and alumina are dispersed and generated in the carrier, as shown in FIG. 1, the noble metal as a catalyst component is deposited on the alumina or alumina-lanthanum reaction product. Is non-selectively supported. In other words, in the conventional catalyst, the noble metal supported on lanthanum aluminate has high activity and high heat resistance, but the other noble metals have not improved heat resistance. Could not be used for a period.
本発明は、ランタンアルミネートなる化合物が担持貴
金属触媒の耐熱性および活性を高める原因物質であるこ
とに着目したものであり、その化合物上に貴金属成分を
選択的に担持することにより、触媒の性能を最大限に引
き出すものである。ランタンアルミネート上に担持され
た貴金属成分はLaと電子的相互作用を起こす。すなわ
ち、Laから貴金属成分への電子の移行が生じることによ
って貴金属は還元状態を呈し、これが安定に保持される
ものと考えられる。The present invention focuses on the fact that a compound called lanthanum aluminate is a substance that increases the heat resistance and activity of a supported noble metal catalyst, and by selectively supporting a noble metal component on the compound, the performance of the catalyst is improved. To bring out the best. The noble metal component supported on lanthanum aluminate causes an electronic interaction with La. That is, it is considered that the transfer of electrons from La to the noble metal component causes the noble metal to exhibit a reduced state, and this is stably maintained.
本発明になる触媒では、第２図に示したように、貴金
属が担持されたランタンアルミネートが耐火性無機担体
上に分散してその表面を被覆しているため、高活性でか
つ高耐熱性が実現できる。特に、上記ランタンアルミネ
ートを得る際にαアルミナを用いる方法は、経済的かつ
手軽な方法として優れている。αアルミナは、安定であ
り表面積が10m2/g以下と極めて小さいために、ランタン
化合物と反応する場合、LaとAlの量的関係がランタンア
ルミネートを得るのに好都合（La:Al＝1:1）になると考
えられる。すなわち、高表面積かつ活性なアルミナ原料
を用いるとLaの周りのAlの量が等量よりも多くなり、ラ
ンタンβアルミナ（La2O3・11Al2O3）のような副生成物
ができる確率が高くなる。これに対して、表面積の小さ
なαアルミナをアルミナ原料に用いた場合、Laの周りの
Alの量が等量に近くなり、ランタンアルミネートが選択
的に生成し易くなる。さらに、αアルミナを用いた場合
の有利な点として、未反応分のαアルミナが残っても、
その表面積が極端に小さいために、それは無視できると
いうことがある。すなわち、不活性かつ表面積の小さな
αアルミナ上に担持される貴金属はほとんど無視できる
量でしかなく、無駄な貴金属成分を極力抑えられるので
ある。従来は不活性で触媒担体の原料としては好ましく
ないとされているαアルミナの特性を逆に利用したのが
本発明の特徴である。In the catalyst according to the present invention, as shown in FIG. 2, the lanthanum aluminate supporting the noble metal is dispersed on the refractory inorganic carrier and covers the surface thereof, so that the catalyst has high activity and high heat resistance. Can be realized. Particularly, the method using α-alumina when obtaining the lanthanum aluminate is excellent as an economical and easy method. Since α-alumina is stable and has an extremely small surface area of 10 m 2 / g or less, when reacting with a lanthanum compound, the quantitative relationship between La and Al is favorable for obtaining lanthanum aluminate (La: Al = 1: It is thought to be 1). In other words, when a high surface area and active alumina raw material is used, the amount of Al around La becomes larger than the equivalent amount, and the probability that by-products such as lanthanum β-alumina (La 2 O 3 · 11Al 2 O 3 ) are formed Will be higher. In contrast, when α-alumina with a small surface area is used as the alumina raw material,
The amount of Al becomes close to the equivalent amount, and lanthanum aluminate is easily produced selectively. Further, as an advantage of using α-alumina, even if unreacted α-alumina remains,
It may be negligible because of its extremely small surface area. That is, the amount of the noble metal supported on α-alumina, which is inert and has a small surface area, is almost negligible, and wasteful noble metal components can be suppressed as much as possible. It is a feature of the present invention that the characteristics of α-alumina, which is conventionally inactive and unfavorable as a raw material for the catalyst carrier, are used in reverse.
本発明において用いられる耐火性無機担体としてはア
ルミナ、コージェライトなどを用いることができるが、
できるだけ表面積および細孔容積の大きい担体が好まし
く、比表面積は60m2/g、細孔容積0.1ml/g以上であるこ
とが望ましい。As the refractory inorganic carrier used in the present invention, alumina, cordierite and the like can be used,
A carrier having a surface area and a pore volume as large as possible is preferable, and the specific surface area is desirably 60 m 2 / g and the pore volume is 0.1 ml / g or more.
ランタンアルミネートを得るにはアルミニウム化合物
とランタン化合物とを反応させる。このときのアルミニ
ウム化合物としては、γ、θ、δ等の転移性アルミナや
硝酸アルミニウム等を用いることができるが、αアルミ
ナを用いる方法は上記の理由により好ましい。αアルミ
ナとしては、できるだけ純度が高く、粒径の細かいもの
が好ましく、純度90％以上、粒径３μｍ以下であること
が望ましい。また、共沈法やアルコキシド法を用いる
と、均一性が高く、粒径の細かいランタンアルミネート
を得ることができるので好ましい。ランタン原料として
は硝酸ランタン（La（NO3）３）、酢酸ランタン（La（C
H3COO）３）等を用いることができる。To obtain lanthanum aluminate, an aluminum compound is reacted with a lanthanum compound. As the aluminum compound at this time, transition alumina such as γ, θ, and δ, aluminum nitrate, and the like can be used, and the method using α-alumina is preferable for the above-mentioned reason. As the α-alumina, those having as high a purity as possible and having a fine particle diameter are preferable, and those having a purity of 90% or more and a particle diameter of 3 μm or less are desirable. Use of a coprecipitation method or an alkoxide method is preferable because lanthanum aluminate having high uniformity and a small particle diameter can be obtained. Lanthanum raw materials include lanthanum nitrate (La (NO 3 ) 3 ) and lanthanum acetate (La (C
H 3 COO) 3 ) can be used.
ランタンアルミネートを得るためには、アルミナ原料
とランタン化合物とを混合した後、加熱、焼成して反応
させる。このとき、焼成温度は1,100℃以下が好まし
い。これ以上ではランタンアルミネートの結晶成長が著
しく、触媒の表面積が小さくなり、貴金属成分が十分に
分散させることができなくなる。In order to obtain lanthanum aluminate, an alumina raw material and a lanthanum compound are mixed, and then heated and fired to cause a reaction. At this time, the firing temperature is preferably 1,100 ° C. or less. Above this, the crystal growth of lanthanum aluminate is remarkable, the surface area of the catalyst becomes small, and the noble metal component cannot be sufficiently dispersed.
触媒成分を担持した後は、通常の調製法によって触媒
となすことができるが、ランタンアルミネート上に貴金
属成分を強固に固定するために、400〜800℃の温度で焼
成を施すことが好ましい。After supporting the catalyst component, the catalyst can be used as a catalyst by a usual preparation method. However, in order to firmly fix the noble metal component on the lanthanum aluminate, it is preferable to perform calcination at a temperature of 400 to 800 ° C.
ランタンアルミネート単独あるいは貴金属成分を担持
したランタンアルミネートを上記耐火性無機担体上に分
散担持するには湿式混練法が有効である。このときラン
タンアルミネートの粒子はできるだけ細かいことが好ま
しく、平均粒径１μｍ以下とするのが望ましい。The wet kneading method is effective for dispersing and supporting lanthanum aluminate alone or a lanthanum aluminate carrying a noble metal component on the refractory inorganic carrier. At this time, the lanthanum aluminate particles are preferably as fine as possible, and the average particle diameter is desirably 1 μm or less.
触媒を実際に使用する場合には、耐火性無機担体は粒
状、柱状、リング状、板状、繊維状あるいはハニカム状
等使用条件に適切な形状を選択することができる。この
耐火性無機担体上にさらに高比表面積のアルミナをはじ
めとする耐火性無機担体を予めコーティングし、その上
にランタンアルミネートをコーティングすることもでき
る。When the catalyst is actually used, the shape of the refractory inorganic carrier can be selected from granules, columns, rings, plates, fibers, honeycombs, and other shapes suitable for use conditions. A refractory inorganic carrier such as alumina having a higher specific surface area may be coated on the refractory inorganic carrier in advance, and lanthanum aluminate may be coated thereon.
次に、本発明を具体的実施例を用いて詳細に説明す
る。Next, the present invention will be described in detail using specific examples.
参考例１ 硝酸アルミニウム40gと硝酸ランタン60.9gとを蒸留水
500mlに溶解し、激しく撹拌しながら28％アンモニア水
を添加して沈澱を生成させた。それを加熱し、蒸発乾
固、次いでこれを大気中120℃で24時間乾燥した。得ら
れた粉末を大気中で1,000℃２時間焼成することによっ
てランタンアルミネートを得た。これをボールミルで24
時間湿式粉砕して平均粒径0.5μｍとした後、蒸留水500
mlによく分散させた。これに平均粒径３μｍ、比表面積
160m2/gのγアルミナ110gを添加して１時間撹拌した
後、加熱して水分を蒸発させることによって、上記γア
ルミナ表面にランタンアルミネートを担持した。この粉
体を大気中600℃で5h焼成して、上記γアルミナ表面に
ランタンアルミネートの被覆層を形成した。この粉体を
ボールミルで24時間湿式粉砕し平均粒径0.5μｍとし、
さらに適当に水分を調節し撹拌して50％のスラリを得
た。このスラリに、触媒の白金担持量が1.0wt％となる
ように調製しておいたテトラアンミン白金（II）硝酸塩
（Pt（NH3）４（NO3）２）の水溶液100mlを添加し１時
間撹拌した後、加熱混練、蒸発乾固した。得られた粉末
を大気中で120℃４時間乾燥した後、550℃2h焼成し、適
当に粉砕して10〜20meshの粒状の担持白金触媒（白金担
持量1wt％）を得た。Reference Example 1 40 g of aluminum nitrate and 60.9 g of lanthanum nitrate were distilled water.
Dissolved in 500 ml and added 28% aqueous ammonia with vigorous stirring to form a precipitate. It was heated and evaporated to dryness, which was then dried in air at 120 ° C. for 24 hours. The obtained powder was calcined in the atmosphere at 1,000 ° C. for 2 hours to obtain lanthanum aluminate. This is a ball mill 24
After wet pulverization for 0.5 hour to average particle size, distilled water 500
well dispersed in ml. The average particle size is 3 μm, specific surface area
After adding 110 g of 160 m 2 / g of γ-alumina and stirring for 1 hour, the lanthanum aluminate was supported on the γ-alumina surface by heating to evaporate water. This powder was fired at 600 ° C. in the air for 5 hours to form a lanthanum aluminate coating layer on the γ-alumina surface. This powder is wet-ground with a ball mill for 24 hours to an average particle size of 0.5 μm,
Further, the water content was appropriately adjusted and stirred to obtain a 50% slurry. To this slurry was added 100 ml of an aqueous solution of tetraammineplatinum (II) nitrate (Pt (NH 3 ) 4 (NO 3 ) 2 ) prepared so that the amount of supported platinum on the catalyst was 1.0 wt%, followed by stirring for 1 hour. Then, the mixture was heated and kneaded and evaporated to dryness. The obtained powder was dried in air at 120 ° C. for 4 hours, calcined at 550 ° C. for 2 hours, and pulverized appropriately to obtain a granular supported platinum catalyst of 10 to 20 mesh (platinum supported amount: 1 wt%).
参考例２ 参考例１において硝酸アルミニウム40gをαアルミナ
（住友アルミニウム精錬（株）社製易焼結性アルミナAE
S−11）20gとし、共沈法ではなく、混練法によってラン
タンアルミネートを得た他は同様にして粒状触媒を得
た。Reference Example 2 In Reference Example 1, 40 g of aluminum nitrate was replaced with α-alumina (Sumitomo Aluminum Refining Co., Ltd.'s easily sinterable alumina AE).
S-11) A granular catalyst was obtained in the same manner except that lanthanum aluminate was obtained by a kneading method instead of a coprecipitation method by setting it to 20 g.
実施例１ 硝酸アルミニウム40gと硝酸ランタン60.9gとを蒸留水
500mlに溶解し、激しく撹拌しながら28％アンモニア水
を添加して沈澱を生成させた。それを加熱し、蒸発乾固
した後これを大気中120℃で24時間乾燥した。得られた
粉末を大気中で1,000℃２時間焼成することによってラ
ンタンアルミネートを得た。これをボールミルで24時間
湿式粉砕して平均粒径0.8μｍとした後、適当に水を加
え撹拌して50％のスラリとした。このスラリに、テトラ
アンミン白金（II）硝酸塩2.59gを含有する水溶液100ml
を添加し、約１時間撹拌した後、大気中で550℃２時間
の焼成を施し、ランタンアルミネート上に白金を担持、
固定した。この粉体をボールミルで24時間湿式粉砕して
平均粒径0.5μｍ以下とした後、蒸留水500ml中に添加
し、よく分散させた。これを平均粒径３μｍ、比表面積
160m2/gのγアルミナ110gを添加して１時間撹拌した
後、加熱、蒸発乾固し、大気中で120℃24時間乾燥し
た。次いで、大気中で550℃２時間の焼成を行って、白
金を担持したランタンアルミネートを上記γアルミナ上
に担持、固定した。これを適当に粉砕して10〜20meshの
粒状触媒を得た。Example 1 40 g of aluminum nitrate and 60.9 g of lanthanum nitrate were distilled water
Dissolved in 500 ml and added 28% aqueous ammonia with vigorous stirring to form a precipitate. After it was heated and evaporated to dryness, it was dried in air at 120 ° C. for 24 hours. The obtained powder was calcined in the atmosphere at 1,000 ° C. for 2 hours to obtain lanthanum aluminate. This was wet-pulverized with a ball mill for 24 hours to obtain an average particle diameter of 0.8 μm, and water was appropriately added and stirred to obtain a 50% slurry. 100 ml of an aqueous solution containing 2.59 g of tetraammineplatinum (II) nitrate
After stirring for about 1 hour, calcination is performed at 550 ° C. for 2 hours in the atmosphere, and platinum is supported on lanthanum aluminate.
Fixed. This powder was wet-pulverized with a ball mill for 24 hours to an average particle size of 0.5 μm or less, and then added to 500 ml of distilled water and dispersed well. The average particle size is 3 μm and the specific surface area is
After adding 110 g of 160 m 2 / g of γ-alumina and stirring for 1 hour, the mixture was heated, evaporated to dryness, and dried in air at 120 ° C. for 24 hours. Next, calcination was performed at 550 ° C. for 2 hours in the atmosphere, and lanthanum aluminate supporting platinum was supported and fixed on the γ-alumina. This was appropriately pulverized to obtain a granular catalyst of 10 to 20 mesh.
参考例３ 参考例１において、テトラアンミン白金（II）硝酸塩
の水溶液100mlを硝酸パラジウム水溶液100ml（パラジウ
ム含有量4.0g）に替え、触媒の焼成温度を550℃から700
℃とした他は同様にして触媒となした（パラジウム担持
量3wt％）。Reference Example 3 In Reference Example 1, 100 ml of an aqueous solution of tetraammineplatinum (II) nitrate was replaced with 100 ml of an aqueous solution of palladium nitrate (palladium content: 4.0 g), and the calcination temperature of the catalyst was changed from 550 ° C. to 700
A catalyst was used in the same manner except that the temperature was changed to ° C (palladium loading 3 wt%).
実施例２ 実施例１において、テトラアンミン白金（II）硝酸塩
2.59gを含有する水溶液100mlをパラジウムを4.0g含有す
る硝酸パラジウム水溶液に替え、またランタンアルミネ
ート上に貴金属成分を担持、固定する際の焼成温度を70
0℃とした他は同様にして触媒を得た。Example 2 Example 1 was repeated except that tetraammineplatinum (II) nitrate was used.
Replace 100 ml of the aqueous solution containing 2.59 g with an aqueous palladium nitrate solution containing 4.0 g of palladium, and carry the noble metal component on lanthanum aluminate, and set the firing temperature to 70 when fixing.
A catalyst was obtained in the same manner except that the temperature was changed to 0 ° C.
比較例１ 硝酸ランタン53.6gを含む水溶液500ml中に、実施例１
で用いたγアルミナ100gを添加して、１時間よく撹拌し
た後、加熱して蒸発乾固した。次いでこの混合物を大気
中で900℃２時間焼成し、比表面積110m2/gの触媒担体粉
末を得た。これをボールミルで24時間湿式粉砕して平均
粒径0.5μｍとした後、適当に水分を追加して撹拌し50
％のスラリとした。以下このスラリに、実施例１と同様
に、テトラアンミン白金（II）硝酸塩の水溶液を添加
し、加熱混練、蒸発乾固、乾燥、焼成の過程を経て10〜
20meshの粒状の担持白金触媒（白金担持量1wt％）を得
た。Comparative Example 1 Example 1 was placed in 500 ml of an aqueous solution containing 53.6 g of lanthanum nitrate.
100 g of γ-alumina used in the above was added, and the mixture was stirred well for 1 hour, then heated and evaporated to dryness. Next, this mixture was calcined in the air at 900 ° C. for 2 hours to obtain a catalyst support powder having a specific surface area of 110 m 2 / g. This was wet-pulverized with a ball mill for 24 hours to obtain an average particle diameter of 0.5 μm.
% Slurry. Thereafter, an aqueous solution of tetraammineplatinum (II) nitrate was added to this slurry in the same manner as in Example 1, and the mixture was heated and kneaded, evaporated to dryness, dried, and calcined.
A 20-mesh granular supported platinum catalyst (platinum supported amount: 1 wt%) was obtained.
比較例２ 比較例１で得られた触媒担持粉を用いて、実施例４と
同様の操作で、パラジウム担持量3wt％の粒状の触媒を
得た。Comparative Example 2 Using the catalyst-supporting powder obtained in Comparative Example 1, a granular catalyst having a palladium-supporting amount of 3 wt% was obtained in the same manner as in Example 4.
試験例 実施例１、２、比較例１、２および参考例１〜３の触
媒の耐熱性を評価する目的で、次ぎに示す条件で一酸化
炭素の燃焼反応試験を行った。触媒の耐熱性は、触媒調
製直後の活性（初期活性）に対して、空気中で1,000℃3
0時間の熱処理を施した後の活性低下の程度で判定し
た。Test Examples In order to evaluate the heat resistance of the catalysts of Examples 1 and 2, Comparative Examples 1 and 2, and Reference Examples 1 to 3, a combustion reaction test of carbon monoxide was performed under the following conditions. The heat resistance of the catalyst is 1,000 ° C3 in air compared to the activity immediately after catalyst preparation (initial activity).
Judgment was made based on the degree of activity decrease after heat treatment for 0 hours.
触媒:10〜20mesh粒状触媒、2cc 反応管：内径20mmパイレックスガラス管 ガス組成:CO 3,500ppm O2 17％ （空気ベース） ガス流量:7.12l/min 空間速度:105,000h-1 また、燃焼反応試験開始前には、乾燥空気中で200℃
２時間のエージングを施した。Catalyst: 10-20mesh granular catalyst, 2cc Reaction tube: Pyrex glass tube with inner diameter 20mm Gas composition: CO 3,500ppm O 2 17% (air base) Gas flow rate: 7.12l / min Space velocity: 105,000h- 1 Also combustion reaction test Before starting, 200 ° C in dry air
Aged for 2 hours.
得られた結果を第３図に示した。また、第４図は触媒
の性能を比較するため、一酸化炭素燃焼率50％時の触媒
層入口温度を初期と1,000℃30時間の熱処理後でプロッ
トしたものである。本発明になる触媒は、比較例で得ら
れた従来触媒に比べ燃焼率50％時の触媒層入口温度の低
下が少なく、耐熱性が一段と優れていることがわかる。The results obtained are shown in FIG. FIG. 4 is a plot of the catalyst layer inlet temperature at a carbon monoxide combustion rate of 50% at the initial stage and after a heat treatment at 1,000 ° C. for 30 hours in order to compare the performances of the catalysts. It can be seen that the catalyst according to the present invention has a smaller decrease in the catalyst layer inlet temperature at a combustion rate of 50% than the conventional catalyst obtained in the comparative example, and is more excellent in heat resistance.
本発明によれば、触媒成分をランタンアルミネート上
に選択的に担持することにより、例えば1,000℃以下の
温度条件で長期間使用可能な高耐熱性触媒を提供するこ
とができる。また、本触媒では、高価な貴金属成分を有
効に使用しているので経済的な効果も大きい。According to the present invention, by selectively supporting a catalyst component on lanthanum aluminate, it is possible to provide a highly heat-resistant catalyst that can be used for a long time under a temperature condition of, for example, 1,000 ° C. or less. Further, in the present catalyst, an expensive precious metal component is effectively used, so that the economic effect is large.
第１図は、従来法で得られる触媒表面のモデル説明図、
第２図は、本発明になる触媒の表面モデル説明図、第３
図は、実施例、比較例および参考例の各触媒の初期活性
および1,000℃30時間後の活性を示した図。第４図は、
実施例、比較例および参考例の各触媒の一酸化炭素燃焼
率50％時の触媒層入口温度を初期と1,000℃30時間の熱
処理後でプロットした図。FIG. 1 is a model explanatory view of a catalyst surface obtained by a conventional method,
FIG. 2 is an explanatory view of a surface model of the catalyst according to the present invention, FIG.
The figure shows the initial activity and the activity after 1,000 hours at 1,000 ° C. of the catalysts of Examples, Comparative Examples and Reference Examples. FIG.
The figure which plotted the catalyst layer entrance temperature at the time of 50% of carbon monoxide burning rate of each catalyst of an Example, a comparative example, and a reference example at the initial stage and after the heat treatment of 1,000 degreeC for 30 hours.
Claims (2)
アルミネートを第二成分、白金およびパラジウムから選
ばれた一種以上の貴金属を第三成分とする燃焼用触媒の
製造方法において、予め調製されたランタンアルミネー
トに前記貴金属成分を担持し、これを第一成分である耐
火性無機担体表面に被覆することを特徴とする燃焼用触
媒の製造方法。1. A method for producing a combustion catalyst comprising a refractory inorganic carrier as a first component, a lanthanum aluminate as a second component, and at least one noble metal selected from platinum and palladium as a third component. A method for producing a combustion catalyst, comprising: supporting the noble metal component on the lanthanum aluminate thus obtained, and coating the noble metal component on the surface of the refractory inorganic carrier as the first component.
ートをαアルミナとランタン化合物との反応により調製
することを特徴とする燃焼用触媒の製造方法。2. The method according to claim 1, wherein lanthanum aluminate is prepared by reacting α-alumina with a lanthanum compound.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1184269A JP2930975B2 (en) | 1989-07-17 | 1989-07-17 | Method for producing combustion catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1184269A JP2930975B2 (en) | 1989-07-17 | 1989-07-17 | Method for producing combustion catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0352642A JPH0352642A (en) | 1991-03-06 |
| JP2930975B2 true JP2930975B2 (en) | 1999-08-09 |
Family
ID=16150365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1184269A Expired - Fee Related JP2930975B2 (en) | 1989-07-17 | 1989-07-17 | Method for producing combustion catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2930975B2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05293388A (en) * | 1992-04-17 | 1993-11-09 | Babcock Hitachi Kk | Production of metal honeycomb catalyst carrier for purification of exhaust gas |
| US5948723A (en) * | 1996-09-04 | 1999-09-07 | Engelhard Corporation | Layered catalyst composite |
| CN1100607C (en) * | 1998-02-25 | 2003-02-05 | 中国科学院大连化学物理研究所 | Active hetorogeneously dispersed catalyst for nitric acid tail gas burning to raise temperature and its preparation |
| EP0982541B1 (en) * | 1998-08-28 | 2003-01-02 | N.V. Bekaert S.A. | Undulated membrane for radiant gas burners |
| JP3843102B2 (en) | 2003-08-06 | 2006-11-08 | 本田技研工業株式会社 | Exhaust gas purification catalyst, method for producing the same, and exhaust gas purification catalyst device |
| JP3843090B2 (en) | 2003-09-12 | 2006-11-08 | 本田技研工業株式会社 | Exhaust gas purification catalyst, method for producing the same, and exhaust gas purification catalyst device for vehicles |
| JP4325648B2 (en) | 2005-10-24 | 2009-09-02 | トヨタ自動車株式会社 | Catalyst carrier and exhaust gas purification catalyst |
| CN110116009A (en) * | 2019-05-30 | 2019-08-13 | 陕西省煤化工工程技术研究中心 | Containing wet VOCs catalysis oxidation integral catalyzer and its preparation method and application |
-
1989
- 1989-07-17 JP JP1184269A patent/JP2930975B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0352642A (en) | 1991-03-06 |
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