JP3760257B2 - Method for producing ammonia synthesis catalyst and catalyst obtained by the method - Google Patents
Method for producing ammonia synthesis catalyst and catalyst obtained by the method Download PDFInfo
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- JP3760257B2 JP3760257B2 JP35721798A JP35721798A JP3760257B2 JP 3760257 B2 JP3760257 B2 JP 3760257B2 JP 35721798 A JP35721798 A JP 35721798A JP 35721798 A JP35721798 A JP 35721798A JP 3760257 B2 JP3760257 B2 JP 3760257B2
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- Prior art keywords
- activated carbon
- ammonia synthesis
- ruthenium
- synthesis catalyst
- catalyst
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- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
Description
【０００１】
【発明の属する技術分野】
本発明は、工業的に操作し易いアンモニア合成触媒の製造方法および同方法で得られた触媒に関するものである。
【０００２】
【従来の技術】
活性炭を触媒担体としてこれにルテニウムのような貴金属を担持したアンモニア合成触媒において、高活性を得るためには同触媒を水素気流下、８５０℃以上の高温で２４時間以上処理して活性炭中の官能基を除去する必要がある。
【０００３】
【発明が解決しようとする課題】
しかし、水素気流下、８５０℃以上、２４時間以上という過酷な処理条件で触媒に処理を施すには、安全対策を施した設備および処理中の監視のための人員が必要であり、触媒製造のコスト高を招く要因となる。また、高温で水素を扱うのははなはだ危険な作業である。
【０００４】
本発明の目的は、上記の点に鑑み、触媒製造コストの増加の要因となる安全対策を施した設備や監視のための人員の必要がなくかつ活性炭中の官能基を安全に除去することができるアンモニア合成触媒の製造方法を提供することにある。
【０００５】
【課題を解決するための手段】
本発明によるアンモニア合成触媒の製造方法は、活性炭をアルカリ金属水酸化物またはアルカリ土類金属水酸化物の水溶液に浸漬した後、水洗し、乾燥した後、該活性炭に貴金属とアルカリ土類金属とを担持させることを特徴とする方法である。
【０００６】
担持前の活性炭をアルカリ処理する方法としては、予め、約１１０℃で１時間以上乾燥させた活性炭をＫＯＨ、ＮａＯＨをはじめとするアルカリ金属水酸化物の水溶液、またはＣａ（ＯＨ）2 、Ｍｇ（ＯＨ）2 等のアルカリ土類金属水酸化物の水溶液に浸漬する方法が好ましい。浸漬時間は、上記水溶液の濃度、温度等にもよるが、通常は１〜２４時間である。
【０００７】
その後、活性炭を充分水洗し、約１１０℃で１時間以上空気下で乾燥させる。
【０００８】
活性炭はハニカム形状に成型されたものであることが好ましい。
【０００９】
貴金属としてはルテニウムが好ましい。たとえば、アルカリ処理活性炭を、Ｒｕ3 （ＣＯ）12をはじめとするルテニウムのカルボニル化合物または錯体、塩化物をはじめとするルテニウムの水溶性化合物を用いてルテニウムを活性炭に担持する。
【００１０】
アルカリ金属、アルカリ土類金属および希土類金属としては、硝酸塩、炭酸塩をはじめとする水溶性化合物の形態をなすものが好ましく用いられる。
【００１１】
ルテニウムを活性炭に担持するには、ルテニウム換算で１〜４０ｇ／ｌの濃度のルテニウム化合物溶液に活性炭を１〜２４時間浸漬する方法が好ましい。この浸漬によって、活性炭へのルテニウム化合物の吸着現象を利用してルテニウムを担持させることができる。その後、ルテニウム溶液から活性炭を取り出し、充分垂れ切りを行った後、約１１０℃で１時間以上空気下で乾燥する。
【００１２】
活性炭に担持したルテニウム化合物からアニオンを除去するために、ルテニウムを担持した活性炭を窒素または水素雰囲気下で温度３５０〜５００℃で１〜３時間熱処理することが好ましい。この時、熱処理温度までの昇温速度を１．５〜１０℃／ｍｉｎとすることが好ましい。
【００１３】
次いで、ルテニウム担持活性炭をアルカリ金属、アルカリ土類金属および希土類金属の硝酸塩、炭酸塩をはじめとする水溶性化合物の水溶液に１時間以上浸漬し、アルカリ金属、アルカリ土類金属および希土類金属をルテニウム担持活性炭に吸着担持する。その後、これを水溶液から取り出し充分垂れ切りを行った後、約１１０℃で１時間以上空気下で乾燥する。
【００１４】
乾燥後、水素またはアンモニア合成ガス（水素＋窒素）の雰囲気下で約４５０℃まで徐々に昇温し約４５０℃で２時間以上、好ましくは３〜５時間保持し、担持したアルカリ金属、アルカリ土類金属および希土類金属の水溶性化合物からアニオンを除去する。
【００１５】
上記方法で調製した触媒は、８５０℃で４８時間以上水素処理した活性炭を用いた従来の触媒と比較して、同等またはそれ以上のアンモニア合成活性を示す。
【００１６】
【発明の実施の形態】
実施例１
（ｉ）バインダーとして酸化珪素−酸化アルミニウムを約３０％含有する活性炭ハニカムを１１０℃で１時間乾燥した。乾燥後の重量は、約０．８ｇであった。この乾燥活性炭ハニカムを１ＮのＫＯＨ水溶液４０ｍｌに２４時間浸漬した。次いで、同ハニカムを後ＫＯＨ水溶液から取り出し、イオン交換水で水洗後、１００ｍｌのイオン交換水中に２４時間浸漬した。その後、これを後イオン交換水から取り出し１１０℃で１時間乾燥した。
【００１７】
（ii）この処理活性炭をルテニウム換算で１０ｇ／ｌの塩化ルテニウム水溶液２０ｍｌに２４時間浸漬した。次いで、これを後水溶液から取り出し充分垂れ切りを行った後、１１０℃で１時間乾燥した。
【００１８】
（iii）乾燥後のルテニウム担持活性炭を水素雰囲気下、１００℃／ｈの速度で ２００℃まで昇温し２００℃にて１時間保持した後、１０℃／ｍｉｎの速度で４５０℃まで昇温し４５０℃にて２時間保持し、ルテニウム担持活性炭中の塩素分を除去した。
【００１９】
（iv）上記処理を行ったルテニウム担持活性炭を０．０９２モル／ｌに調整した硝酸バリウム水溶液に浸漬した。これをそのまま一晩放置した後、液から取り出し充分垂れ切りを行った後１１０℃で１時間乾燥した。
【００２０】
（ｖ）乾燥品をアンモニア合成ガス雰囲気（Ｈ2 ／Ｎ2 ＝３）下、１０℃／ｍｉｎの速度で４５０℃まで昇温し、この温度にて２時間保持し触媒中の硝酸根を除去した。上記処理品を所定の温度まで冷却し、アンモニア合成触媒を得た。
【００２１】
性能試験
アンモニア合成反応速度を測定した。
【００２２】
上記触媒を用い次の反応条件でアンモニアの合成反応速度（触媒単位重量当たりの活性）を測定した。測定結果を表１に示す。
【００２３】
塩化ルテニウム水溶液の濃度および浸漬時間を変化させた点を除いて、実施例１と同様の操作を行い、ルテニウム担持量の異なる触媒を調製した。
【００２４】
これらの触媒を用い、実施例１と同様の反応条件で反応速度を測定した。この結果を図１に示す。
【００２５】
【発明の効果】
本発明によれば、担持前に活性炭をアルカリ処理しておくことによって、触媒製造コストの増加の要因となる安全対策を施した設備や監視のための人員の必要がない上に、活性炭中の官能基を安全に除去することができる。こうして、工業的に操作し易いアンモニア合成触媒の製造方法を提供することができる。
【図面の簡単な説明】
【図１】ルテニウム（Ｒｕ）担持量と反応速度の関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an ammonia synthesis catalyst that is industrially easy to operate and a catalyst obtained by the method.
[0002]
[Prior art]
In order to obtain high activity in an ammonia synthesis catalyst in which activated carbon is used as a catalyst carrier and on which a noble metal such as ruthenium is supported, the catalyst is treated at a high temperature of 850 ° C. or higher for 24 hours or more in a hydrogen gas stream. The group needs to be removed .
[0003]
[Problems to be solved by the invention]
However, in order to treat the catalyst under harsh treatment conditions of 850 ° C. or more and 24 hours or more under a hydrogen stream, equipment with safety measures and personnel for monitoring during the treatment are required. It becomes a factor incurring high cost. Also, handling hydrogen at high temperatures is a very dangerous task.
[0004]
In view of the above points, the object of the present invention is to eliminate the need for safety-equipped equipment and monitoring personnel that cause an increase in catalyst production costs, and to safely remove functional groups in activated carbon. An object of the present invention is to provide a process for producing an ammonia synthesis catalyst.
[0005]
[Means for Solving the Problems]
In the method for producing an ammonia synthesis catalyst according to the present invention, activated carbon is immersed in an aqueous solution of an alkali metal hydroxide or alkaline earth metal hydroxide, washed with water, dried, and then the activated carbon is mixed with a noble metal and an alkaline earth metal. It is a method characterized by carrying | supporting .
[0006]
As a method for alkali-treating the activated carbon before loading, activated carbon previously dried at about 110 ° C. for 1 hour or more is treated with an aqueous solution of an alkali metal hydroxide such as KOH or NaOH, or Ca (OH) 2 , Mg ( A method of immersing in an aqueous solution of an alkaline earth metal hydroxide such as (OH) 2 is preferred. Although the immersion time depends on the concentration, temperature, etc. of the aqueous solution, it is usually 1 to 24 hours.
[0007]
Thereafter, the activated carbon is thoroughly washed with water and dried at about 110 ° C. for 1 hour or longer in air.
[0008]
The activated carbon is preferably molded into a honeycomb shape.
[0009]
Ruthenium is preferred as the noble metal. For example, ruthenium is supported on activated carbon by using an alkali-treated activated carbon using a ruthenium carbonyl compound or complex such as Ru 3 (CO) 12 or a ruthenium water-soluble compound such as chloride.
[0010]
As the alkali metal, alkaline earth metal, and rare earth metal, those in the form of water-soluble compounds including nitrates and carbonates are preferably used.
[0011]
In order to carry ruthenium on activated carbon, a method of immersing activated carbon in a ruthenium compound solution having a concentration of 1 to 40 g / l in terms of ruthenium for 1 to 24 hours is preferable. By this immersion, ruthenium can be supported by utilizing the adsorption phenomenon of the ruthenium compound on the activated carbon. Thereafter, the activated carbon is taken out from the ruthenium solution, sufficiently suspended, and then dried in air at about 110 ° C. for 1 hour or longer.
[0012]
In order to remove anions from the ruthenium compound supported on the activated carbon, it is preferable to heat-treat the activated carbon supporting ruthenium at a temperature of 350 to 500 ° C. for 1 to 3 hours in a nitrogen or hydrogen atmosphere. At this time, it is preferable that the rate of temperature rise to the heat treatment temperature is 1.5 to 10 ° C./min.
[0013]
Next, the ruthenium-supported activated carbon is immersed in an aqueous solution of a water-soluble compound such as alkali metal, alkaline earth metal and rare earth metal nitrates and carbonates for 1 hour or longer, and the alkali metal, alkaline earth metal and rare earth metal are supported on ruthenium. Adsorbed on activated carbon. Thereafter, this is taken out from the aqueous solution and sufficiently dripped, and then dried in air at about 110 ° C. for 1 hour or longer.
[0014]
After drying, the temperature is gradually raised to about 450 ° C. in an atmosphere of hydrogen or ammonia synthesis gas (hydrogen + nitrogen) and maintained at about 450 ° C. for 2 hours or more, preferably 3 to 5 hours. Anions are removed from water-soluble compounds of metal and rare earth metals.
[0015]
The catalyst prepared by the above method exhibits an ammonia synthesis activity equal to or higher than that of a conventional catalyst using activated carbon that has been hydrogen-treated at 850 ° C. for 48 hours or longer.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Example 1
(I) An activated carbon honeycomb containing about 30% of silicon oxide-aluminum oxide as a binder was dried at 110 ° C. for 1 hour. The weight after drying was about 0.8 g. This dried activated carbon honeycomb was immersed in 40 ml of 1N KOH aqueous solution for 24 hours. Next, the honeycomb was taken out from the aqueous KOH solution, washed with ion exchange water, and immersed in 100 ml of ion exchange water for 24 hours. Thereafter, this was taken out from the deionized water and dried at 110 ° C. for 1 hour.
[0017]
(Ii) The treated activated carbon was immersed in 20 ml of a 10 g / l ruthenium chloride aqueous solution in terms of ruthenium for 24 hours. Subsequently, this was taken out from the post-aqueous solution and sufficiently dripped, and then dried at 110 ° C. for 1 hour.
[0018]
(Iii) The dried ruthenium-supported activated carbon is heated to 200 ° C. at a rate of 100 ° C./h under a hydrogen atmosphere, held at 200 ° C. for 1 hour, and then heated to 450 ° C. at a rate of 10 ° C./min. Holding at 450 ° C. for 2 hours, the chlorine content in the ruthenium-supported activated carbon was removed.
[0019]
(Iv) The ruthenium-supported activated carbon subjected to the above treatment was immersed in an aqueous barium nitrate solution adjusted to 0.092 mol / l. This was left as it was overnight, then taken out from the solution, sufficiently dripped and dried at 110 ° C. for 1 hour.
[0020]
(V) The dried product was heated to 450 ° C. at a rate of 10 ° C./min in an ammonia synthesis gas atmosphere (H 2 / N 2 = 3) and held at this temperature for 2 hours to remove nitrate radicals in the catalyst. did. The treated product was cooled to a predetermined temperature to obtain an ammonia synthesis catalyst.
[0021]
Performance test The ammonia synthesis reaction rate was measured.
[0022]
Using the catalyst, the ammonia synthesis reaction rate (activity per unit weight of catalyst) was measured under the following reaction conditions. The measurement results are shown in Table 1.
[0023]
Except that the concentration of the aqueous ruthenium chloride solution and the immersion time were changed, the same operation as in Example 1 was performed to prepare catalysts having different ruthenium loadings.
[0024]
Using these catalysts, the reaction rate was measured under the same reaction conditions as in Example 1. The result is shown in FIG.
[0025]
【The invention's effect】
According to the present invention, the activated carbon is alkali-treated before loading, so that there is no need for safety-equipped equipment and monitoring personnel that cause an increase in catalyst production cost, Functional groups can be removed safely. Thus, it is possible to provide a method for producing an ammonia synthesis catalyst that is industrially easy to operate.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the amount of ruthenium (Ru) supported and the reaction rate.
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35721798A JP3760257B2 (en) | 1998-12-16 | 1998-12-16 | Method for producing ammonia synthesis catalyst and catalyst obtained by the method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35721798A JP3760257B2 (en) | 1998-12-16 | 1998-12-16 | Method for producing ammonia synthesis catalyst and catalyst obtained by the method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000176284A JP2000176284A (en) | 2000-06-27 |
| JP3760257B2 true JP3760257B2 (en) | 2006-03-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35721798A Expired - Fee Related JP3760257B2 (en) | 1998-12-16 | 1998-12-16 | Method for producing ammonia synthesis catalyst and catalyst obtained by the method |
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| JP (1) | JP3760257B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010098245A1 (en) | 2009-02-27 | 2010-09-02 | 日立造船株式会社 | Ammonia decomposition catalyst |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003088759A (en) * | 2001-09-18 | 2003-03-25 | Mitsubishi Paper Mills Ltd | Low temperature oxidation catalyst filter |
| JP4777670B2 (en) * | 2005-02-25 | 2011-09-21 | 本田技研工業株式会社 | Ammonia synthesis catalyst and method for producing the same |
| JP5039631B2 (en) * | 2008-04-08 | 2012-10-03 | 日立造船株式会社 | Method for producing noble metal supported catalyst |
| CN104084197B (en) * | 2014-07-15 | 2016-04-06 | 福州大学化肥催化剂国家工程研究中心 | A kind of be carrier ruthenium system ammonia synthesis catalyst and the preparation thereof of graphitization active carbon |
-
1998
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010098245A1 (en) | 2009-02-27 | 2010-09-02 | 日立造船株式会社 | Ammonia decomposition catalyst |
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| JP2000176284A (en) | 2000-06-27 |
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