JP3788530B2 - Catalyst regeneration method - Google Patents
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- JP3788530B2 JP3788530B2 JP17962396A JP17962396A JP3788530B2 JP 3788530 B2 JP3788530 B2 JP 3788530B2 JP 17962396 A JP17962396 A JP 17962396A JP 17962396 A JP17962396 A JP 17962396A JP 3788530 B2 JP3788530 B2 JP 3788530B2
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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
- Y02P20/584—Recycling of catalysts
Description
【０００１】
【発明の属する技術分野】
本発明は塩酸の接触酸化により塩素を製造するために使用する酸化クロム系触媒の再生方法に関する。
【０００２】
塩素は食塩の電解により大規模に製造されているが、併産する苛性ソーダとの需要バランスを調整するのが困難な状況になっている。一方、塩化水素は有機化合物の塩素化反応またはホスゲンとの反応の際に大量に副生しているが、その副生量は需要より大幅に多いため、大量の塩化水素がかなりの処理コストをかけて無駄に廃棄されている。
【０００３】
従って、塩化水素から塩素を効率良く回収出来れば、苛性ソーダとの不均衡を生じる事なく、塩素の需要を満たすことが出来る。
【０００４】
【従来の技術】
酸化クロムを塩化水素の酸化触媒として用いる提案もあるが、工業的使用に耐え得る十分な性能を示す結果は報告されていない。
【０００５】
例えば、無水クロム酸または硝酸クロム水溶液を適当な担体に含浸、熱分解して調製した触媒上に塩化水素を４００゜C前後で流通させて塩素を発生させ、触媒が失活した後、塩化水素の供給を停止し、空気を流通させて触媒を再生後、空気の供給を停止して再び塩化水素を流通させる方法が提案されている（英国特許第５８４，７９０号）。
【０００６】
また、重クロム酸塩または暗黒緑色の酸化クロムを担体上に担持した触媒を用いることにより塩化水素と含酸素ガスを反応温度４２０〜４３０゜C、空間速度３８０Ｈr-1で反応させ、平衡値６７.４％の塩化水素転化率が得られている（英国特許第６７６，６６７号）。この際、 空間速度６８０Ｈr-1では転化率６３％である。反応は３４０゜Cでも認められるが、 この場合には空間速度を６５Ｈr-1という低い値にして転化率５２％を得ているにすぎない。これらの方法は反応温度も高く、空間速度も低い為、工業的な実施には無理がある。
【０００７】
一方、クロム酸の水溶液とアンモニアとを反応させて得られる化合物を８００゜C以下の温度で焼成することにより得られる酸化クロム触媒が塩化水素の酸化反応に高活性を示す事が見いだされ（特開昭６１-２７５１０４号公報）、当該触媒を用いることにより、従来既知の触媒より低温かつ高い空時収率で塩素を製造出来るようになった。
【０００８】
しかしながら、当該触媒の問題点として、廃棄塩化水素ガスの酸化反応に使用すると、反応開始後数ケ月の後には活性が低下してくることが挙げられる。その賦活方法として高温気相で塩化水素ガス及び／または含酸素ガスと接触させる方法が提案されているが（特開昭６２-２５４８４６号公報）、この方法により賦活した触媒を廃棄塩化水素ガスの酸化反応に使用すると、反応開始後数日間は新触媒並の活性に戻るが、一週間以上の後には活性が低下し始め、長期的使用には耐え得ないという問題がある。
【０００９】
また、別の賦活方法として当該触媒にクロム塩または酸化クロムの水溶液を含浸させ、８００℃以下の温度で焼成する方法も提案されているが（特開平３-２２１１４５号公報）、この方法により賦活した触媒もまた塩化水素ガスの酸化反応に使用すると、反応開始後数日間は新触媒並の活性に戻るが、一ヵ月以上の後には活性が低下し始め、長期的使用には耐え得ないという問題がある。
【００１０】
銅系の触媒を用いた塩化水素の酸化による塩素の製造法は古くからDeacon反応としてしられており、１８６８年の Deaconの発明による銅系の触媒については、その後塩化銅と塩化カリウムに第３成分として種々の化合物を添加した触媒が多数提案されている。しかしながら、この触媒を工業的に使用するには、反応温度を高くしなければ十分な反応速度が得られず、この為、触媒成分の揮散が起こり、短期間で活性の低下を生じ触媒寿命に致命的な問題点があると共に、触媒が固結し特に、流動床触媒として使用した場合流動化が困難となり触媒として用をなさなくなるという大きな問題点がある事も知られている。
【００１１】
【発明が解決しようとする課題】
本発明の課題は、塩化水素の酸化により塩素を製造するに際して、上述した公知の触媒が有する問題点を解決することであり、活性の低下した酸化クロム触媒の有用な再生方法を提供することである。
【００１２】
【課題を解決するための手段】
本発明の課題解決のため、本発明者らは塩化水素の酸化による塩素の製造に用いる酸化クロムを主成分とする触媒の再生方法について鋭意検討した。
その結果、我々は、活性の低下した酸化クロムを主成分とする触媒に銅、アルカリ金属、希土類金属、および銅以外の遷移金属を含む溶液を含浸させ、８００゜C以下の温度で焼成することにより活性の低下した酸化クロム触媒を賦活、再生でき、しかも従来の酸化クロム触媒の再生方法が有する前述の問題点を生じず、長時間、工業的使用に耐え得る酸化クロム触媒の再生方法を見出し本発明を完成した。
【００１３】
即ち、本発明は、塩化水素を含酸素ガスで酸化し塩素を製造する際に使用した酸化クロムを主成分とする触媒を再生するに際し、該触媒に銅、アルカリ金属、希土類金属、およびコバルトを含む溶液を含浸させ、焼成する事を特徴とする触媒の再生方法である。
【００１４】
【発明の実施の形態】
本発明の方法にベース触媒として用いられる酸化クロムを主成分とする触媒は、例えば硝酸クロム、塩化クロムまたは有機酸のクロム塩等のクロム塩とアンモニアあるいは尿素のようなアンモニアを放出する化合物との反応物と、ケイ素の化合物とから成る混合物を８００゜C以下の温度で焼成する事により製造する。クロムとシリカとの混合比は通常、特に制限はないが、触媒を最終的に焼成して得た後の形態であるＣｒ2Ｏ3とＳｉＯ2の重量比で、Ｃｒ2Ｏ3/ＳｉＯ2＝５／９５〜９５/５の範囲が多用される。
【００１５】
本発明方法の触媒を用い塩素を製造する際に使用される原料の塩化水素は通常、化学工業界では有機化合物の塩素化またはホスゲンとの反応に際して副生する塩化水素を使用するのが経済的であるがそれに限定されるものではない。
【００１６】
塩化水素の酸化剤としては含酸素ガスが使用され、通常、酸素ガスまたは空気が多用される。反応器の形式は固定床でも流動床でも実施可能であるが、塩化水素の酸化反応のように発熱が大きい反応の場合には除熱が容易である流動床が多用される。流動床式の場合には、酸素ガスを、固定床式の場合には空気を使用する場合が多い。
【００１７】
反応に使用する塩化水素と含酸素ガス中の酸素のモル比は、塩化水素１モルに対して酸素１／４モル（当量）前後であり、通常、酸素を当量の５〜２００％過剰に使用する場合が多い。
【００１８】
触媒床に供給する塩化水素は、２００〜１８００（Ｎｌ／Ｈｒ.）Ｋg-cat.の範囲が適している。
【００１９】
反応温度は３００〜４５０゜C、特に３６０〜４２０゜Cで多用される。
本反応は常圧、加圧のいずれでも実施可能であるが、通常１〜１１×１０5Ｐａの加圧下で行うのが好ましい場合が多い。
【００２０】
従来公知の酸化クロムを主成分とする触媒は上記の反応条件で数ケ月ないし半年間反応に使用した場合は活性が低下し、初期に塩化水素の転化率が７０〜８０％を示したものが５０〜６０％になる。
【００２１】
活性の低下した触媒は銅、アルカリ金属、希土類金属、および銅以外の遷移金属を含む溶液を含浸し、８００゜C以下の温度で焼成することにより活性を回復させる事が出来る。
【００２２】
本発明において銅、アルカリ金属、希土類金属、および銅以外の遷移金属を酸化クロムを主成分とする触媒に加える方法としては、含浸法、共沈法、蒸着法等の従来公知の触媒調製法を採用できるが、含浸法がより有効であり、また操作的にも簡便である。
【００２３】
含浸法の一例としては酸化クロムを主成分とする触媒に銅、アルカリ金属、希土類金属、および銅以外の遷移金属を含む溶液を含浸し、８００℃以下の温度で焼成する方法が挙げられる。
【００２４】
本発明方法において 銅、アルカリ金属、および希土類金属の３成分の使用は必須であり、このうちのどの成分が欠けても再生触媒の活性は充分には向上しない。
【００２５】
この３成分の含浸量の影響については、含浸量の増加と共に活性向上の効果がある一方、触媒流動性が低下する傾向がある。そこで、この３成分に銅以外の遷移金属を追加することで触媒活性のさらなる向上、活性経時低下の減少、および含浸量増加に伴う触媒流動性低下の防止を計ることができる。
【００２６】
また、銅以外の遷移金属を溶解した溶液の含浸方法は、銅，アルカリ金属、希土類金属を含む溶液の含浸を行う前、同時、および後に行う、先付け含浸法、同時含浸法、および後付け含浸法が可能であり含浸方法に特に制限はない。
【００２７】
銅成分としては、具体的には例えば硝酸銅、硫酸銅、塩化銅、および酸化銅が使用でき、アルカリ金属、希土類金属、および銅以外の遷移金属も同様に、それらの金属の硝酸塩、硫酸塩、塩化物、および酸化物などが使用でき、具体的に、アルカリ金属成分としては、硝酸カリウム、硫酸カリウム、塩化カリウム、硝酸ナトリウム、硫酸ナトリウム、塩化ナトリウム、酸化ナトリウム等が挙げられる。希土類金属塩としては、ランタン、プラセオジム、ネオジム、プロメチウム、サマリウム、ユウロピウム等の硝酸塩、硫酸塩、ハロゲン化塩、酸化物等が挙げられ、なかでもランタンの塩が好ましい。また、銅以外の遷移金属としては、チタン、バナジウム、マンガン、鉄、コバルト、ニッケル等の硝酸塩、硫酸塩、ハロゲン化塩、酸化物等が挙げられ、なかでもコバルトの塩が好ましい。
【００２８】
銅，アルカリ金属、希土類金属、および銅以外の遷移金属の濃度は、高い程効果が得られるが、酸化クロムを主成分とする触媒のクロムに対して原子比率で 銅＝０.０１〜０.３,カリウム＝０.００５〜０.２,ランタン＝０.０１〜０.３、コバルト＝０.０１〜０.３の範囲が好ましい。
【００２９】
【実施例】
次に、本発明の方法を実施例でさらに詳細に説明する。
実施例１
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。廃塩化水素ガスを３３４ml/min、酸素を１６７ml/minで流動床に流入させ反応管外部を電気炉で内温３８０゜Cに加熱し反応させた。酸素／塩化水素モル比＝１／２、酸素過剰率１００％である。
反応開始３日目の塩化水素の転化率は７３％であった。反応開始３０日目では転化率６７％を示し、６５日目には５５％まで低下した。
この廃触媒にＣｕ（ＮＯ3）2・３Ｈ2Ｏ３.７８ｇ、ＫＮＯ3１.５６ｇ、Ｌａ（ＮＯ3）2・６Ｈ2Ｏ５.３２ｇ、およびＣｏ（ＮＯ3）2・６Ｈ2Ｏ５.９２ｇを溶解した水溶液２７ｍｌを同時に含浸後、４２０℃で５時間焼成した。この再生触媒４０ｇを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は７８％であった。反応開始３０日目では転化率７０％を示し、６５日目には転化率６８％であり、新触媒と同等以上の活性及び寿命を示した。
【００３０】
実施例２
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。実施例１と同様に反応して得られた廃触媒を抜き出し、この廃触媒にＣｕ（ＮＯ3）2・３Ｈ2Ｏ３.７８ｇ、ＫＮＯ3１.５６ｇ、Ｌａ（ＮＯ3）2・６Ｈ2Ｏ５.３２ｇ、およびＣｏ（ＮＯ3）2・６Ｈ2Ｏ２.９６ｇを溶解した水溶液２５ｍｌを含浸後、４２０℃で５時間焼成した。この再生触媒４０ｇを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は７７％であった。反応開始３０日目では転化率６８％を示し、６５日目には転化率６２％であり、新触媒と同等以上の活性及び寿命を示した。
【００３１】
比較例１
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。実施例１と同様に反応して得られた廃触媒を抜き出し、Ｃｕ（ＮＯ3）2・３Ｈ2Ｏ３.７８ｇ、ＫＮＯ3１.５６ｇ、Ｌａ（ＮＯ3）2・６Ｈ2Ｏ５.３２ｇ、を溶解した水溶液２７mlに含浸後、４２０゜Cで５時間焼成した。この再生触媒４０gを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は７５％、反応開始３０日目では転化率６６％を示し、６５日目には転化率５６％であった。
【００３２】
比較例２
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。実施例１と同様に反応して得られた廃触媒を抜き出し、この廃触媒にＣｏ（ＮＯ3）2・６Ｈ2Ｏ５.９２ｇを溶解した水溶液２７mlに含浸後、４２０゜Cで５時間焼成した。この再生触媒４０gを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は５５％であり転化率の向上はなかった。
【００３３】
実施例３
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。実施例１と同様に反応して得られた廃触媒を抜き出し、この廃触媒にＣｕ（ＮＯ3）2・３Ｈ2Ｏ３.７８ｇ、ＫＮＯ3１.５６ｇ、Ｌａ（ＮＯ3）2・６Ｈ2Ｏ５.３２ｇを溶解した水溶液２０ｍｌを含浸後、４２０℃で５時間焼成した。その後Ｃｏ（ＮＯ3）2・６Ｈ2Ｏ５.９２ｇを溶解した水溶液７.４ｍｌを含浸後、４２０℃で５時間焼成した。この再生触媒４０ｇを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は７８％であった。反応開始３０日目では転化率７０％を示し、６５日目には転化率６８％であり、新触媒と同等以上の活性及び寿命を示した。
【００３４】
実施例４
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。実施例１と同様に反応して得られた廃触媒を抜き出し、この廃触媒にＣｕ（ＮＯ3）2・３Ｈ2Ｏ１５.１７ｇ、ＫＮＯ3６.２４ｇ、Ｌａ（ＮＯ3）2・６Ｈ2Ｏ１０.６４ｇ、およびＣｏ（ＮＯ3）2・６Ｈ2Ｏ５.９２ｇを溶解した水溶液５０.０ｍｌを含浸後、４２０℃で５時間焼成した。この再生触媒４０ｇを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は８０％であった。反応開始３０日目では転化率７２％を示し、６５日目には転化率７０％であり、新触媒と同等以上の活性及び寿命を示した。
【００３５】
比較例３
クロミア７５重量％、シリカ２５重量％からなる平均粒径６０μの微小球状流動床用触媒４０g を内径１インチのガラス製流動床反応器に充填した。実施例１と同様に反応して得られた廃触媒を抜き出し、この廃触媒にＣｕ（ＮＯ3）2・３Ｈ2Ｏ１５.１７ｇ、ＫＮＯ3６.２４ｇ、Ｌａ（ＮＯ3）2・６Ｈ2Ｏ１０.６４ｇを溶解した水溶液５０.０ｍｌを含浸後、４２０℃で５時間焼成した。この再生触媒４０ｇを上記と同様にして反応させた。
反応開始３日目の塩化水素の転化率は７９％であった。反応開始３０日目では転化率７１％を示し、６５日目には転化率６９％であり、新触媒と同等以上の活性及び寿命を示すが３０日目以降から触媒流動性がやや低下する傾向が見られた。
【００３６】
【発明の効果】
本発明の方法によれば、塩化水素の酸化反応に長期間使用し、活性が低下した従来公知の酸化クロムを主成分とする触媒を銅、アルカリ金属、希土類金属、および銅以外の遷移金属を含む溶液を含浸させ、８００゜C以下の温度で焼成する事により賦活再生する事ができる。このようにして得られた再生触媒は活性が高く、触媒流動性も良好であり、長期間の寿命試験においても新触媒と同程度の性能を有する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for regenerating a chromium oxide catalyst used for producing chlorine by catalytic oxidation of hydrochloric acid.
[0002]
Chlorine is produced on a large scale by electrolysis of sodium chloride, but it is difficult to adjust the demand balance with the co-produced caustic soda. On the other hand, hydrogen chloride is by-produced in a large amount during the chlorination reaction of organic compounds or with phosgene, but the amount of by-product is much larger than the demand, so a large amount of hydrogen chloride has a considerable processing cost. The waste is wasted over time.
[0003]
Therefore, if chlorine can be efficiently recovered from hydrogen chloride, the demand for chlorine can be satisfied without causing an imbalance with caustic soda.
[0004]
[Prior art]
There is also a proposal to use chromium oxide as an oxidation catalyst for hydrogen chloride, but no results have been reported that show sufficient performance to withstand industrial use.
[0005]
For example, hydrogen chloride is passed through a catalyst prepared by impregnating a suitable carrier with an aqueous solution of chromic anhydride or chromium nitrate and pyrolyzed to generate chlorine by flowing around 400 ° C. After the catalyst is deactivated, hydrogen chloride Is stopped, the air is circulated, the catalyst is regenerated, the air supply is stopped, and hydrogen chloride is circulated again (UK Patent No. 584,790).
[0006]
Further, by using a catalyst in which dichromate or dark green chromium oxide is supported on a carrier, hydrogen chloride and oxygen-containing gas are reacted at a reaction temperature of 420 to 430 ° C. and a space velocity of 380 Hr −1 , and an equilibrium value of 67 A hydrogen chloride conversion of 0.4% has been obtained (British Patent No. 676,667). At this time, the conversion rate is 63% at a space velocity of 680 Hr −1 . The reaction is also observed at 340 ° C., but in this case only a conversion of 52% is obtained with a space velocity as low as 65 Hr −1 . Since these methods have a high reaction temperature and a low space velocity, they are difficult to implement industrially.
[0007]
On the other hand, it has been found that a chromium oxide catalyst obtained by calcining a compound obtained by reacting an aqueous solution of chromic acid with ammonia at a temperature of 800 ° C. or less exhibits high activity in the oxidation reaction of hydrogen chloride (particularly By using this catalyst, chlorine can be produced at a lower temperature and higher space time yield than conventionally known catalysts.
[0008]
However, a problem with the catalyst is that when used for the oxidation reaction of waste hydrogen chloride gas, the activity decreases after several months after the start of the reaction. As an activation method, a method of bringing hydrogen chloride gas and / or oxygen-containing gas into contact with each other in a high-temperature gas phase has been proposed (Japanese Patent Laid-Open No. Sho 62-254846). The catalyst activated by this method is used as waste hydrogen chloride gas. When used in an oxidation reaction, the activity returns to the level of a new catalyst for a few days after the start of the reaction, but after a week or more, the activity starts to decline and there is a problem that it cannot withstand long-term use.
[0009]
As another activation method, a method in which the catalyst is impregnated with an aqueous solution of a chromium salt or chromium oxide and calcined at a temperature of 800 ° C. or lower has been proposed (Japanese Patent Laid-Open No. 3-221145). If the catalyst is also used for the oxidation reaction of hydrogen chloride gas, it will return to the activity of the new catalyst for a few days after the start of the reaction, but the activity will begin to decline after a month or more and it will not be able to withstand long-term use. There's a problem.
[0010]
The production of chlorine by oxidation of hydrogen chloride using a copper-based catalyst has long been the Deacon reaction. For the copper-based catalyst according to the invention of Deacon in 1868, the third is the third Many catalysts with various compounds added as components have been proposed. However, in order to use this catalyst industrially, a sufficient reaction rate cannot be obtained unless the reaction temperature is raised. For this reason, the catalyst components are volatilized, resulting in a decrease in activity in a short period of time and a shortened catalyst life. In addition to fatal problems, it is also known that the catalyst is solidified, and in particular, when used as a fluidized bed catalyst, fluidization becomes difficult and the catalyst cannot be used.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the known catalyst when producing chlorine by oxidation of hydrogen chloride, and to provide a useful method for regenerating a chromium oxide catalyst having reduced activity. is there.
[0012]
[Means for Solving the Problems]
In order to solve the problems of the present invention, the present inventors diligently studied a method for regenerating a catalyst mainly composed of chromium oxide used for producing chlorine by oxidation of hydrogen chloride.
As a result, we impregnate a catalyst based on chromium oxide having a reduced activity as a main component with a solution containing copper, an alkali metal, a rare earth metal, and a transition metal other than copper, and calcine at a temperature of 800 ° C or lower. A method for regenerating a chromium oxide catalyst that can activate and regenerate a chromium oxide catalyst whose activity has been reduced by the above-mentioned method and that can withstand industrial use for a long time without causing the above-mentioned problems of conventional methods for regenerating a chromium oxide catalyst has been found. The present invention has been completed.
[0013]
That is, the present invention regenerates a catalyst mainly composed of chromium oxide used in the production of chlorine by oxidizing hydrogen chloride with an oxygen-containing gas, and copper, alkali metal, rare earth metal, and cobalt are added to the catalyst. A method for regenerating a catalyst, which comprises impregnating a containing solution and calcining.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The catalyst mainly composed of chromium oxide used as the base catalyst in the method of the present invention is, for example, a chromium salt such as chromium nitrate, chromium chloride or a chromium salt of an organic acid and a compound that releases ammonia such as ammonia or urea. It is produced by firing a mixture comprising a reactant and a silicon compound at a temperature of 800 ° C. or lower. The mixing ratio of chromium and silica is usually not particularly limited, but is the weight ratio of Cr 2 O 3 and SiO 2 in the form after the catalyst is finally calcined, and Cr 2 O 3 / SiO 2 = 5/95 to 95/5 is frequently used.
[0015]
The raw material hydrogen chloride used when producing chlorine using the catalyst of the method of the present invention is usually economical in the chemical industry to use hydrogen chloride produced as a by-product in the chlorination of organic compounds or reaction with phosgene. However, the present invention is not limited to this.
[0016]
An oxygen-containing gas is used as an oxidizing agent for hydrogen chloride, and oxygen gas or air is usually used frequently. The reactor can be implemented in either a fixed bed or a fluidized bed. However, in the case of a reaction with a large exotherm such as an oxidation reaction of hydrogen chloride, a fluidized bed that can easily remove heat is frequently used. In the case of a fluidized bed type, oxygen gas is often used, and in the case of a fixed bed type, air is often used.
[0017]
The molar ratio of hydrogen chloride used in the reaction to oxygen in the oxygen-containing gas is around 1/4 mole (equivalent) of oxygen with respect to 1 mole of hydrogen chloride. Usually, oxygen is used in an excess of 5 to 200% of the equivalent. There are many cases to do.
[0018]
The hydrogen chloride supplied to the catalyst bed is suitably in the range of 200 to 1800 (Nl / Hr.) Kg-cat.
[0019]
The reaction temperature is frequently used at 300 to 450 ° C, particularly 360 to 420 ° C.
Although this reaction can be carried out at normal pressure or under pressure, it is often preferable to carry out the reaction under a pressure of usually 1 to 11 × 10 5 Pa.
[0020]
The conventionally known chromium oxide-based catalyst has a reduced activity when used in the reaction for several months to half a year under the above reaction conditions, and initially shows a conversion rate of hydrogen chloride of 70 to 80%. 50-60%.
[0021]
The catalyst having reduced activity can be recovered by impregnating a solution containing copper, alkali metal, rare earth metal, and transition metal other than copper and calcining at a temperature of 800 ° C. or lower.
[0022]
In the present invention, as a method of adding copper, alkali metal, rare earth metal, and transition metal other than copper to the catalyst mainly composed of chromium oxide, conventionally known catalyst preparation methods such as impregnation method, coprecipitation method, vapor deposition method and the like are used. Although it can be employed, the impregnation method is more effective and simple in operation.
[0023]
As an example of the impregnation method, there is a method in which a catalyst containing chromium oxide as a main component is impregnated with a solution containing copper, an alkali metal, a rare earth metal, and a transition metal other than copper and calcined at a temperature of 800 ° C. or lower.
[0024]
In the method of the present invention, the use of three components of copper, alkali metal, and rare earth metal is essential, and the activity of the regenerated catalyst is not sufficiently improved even if any of these components is missing.
[0025]
Regarding the influence of the impregnation amount of these three components, there is an effect of improving the activity with an increase of the impregnation amount, while the catalyst fluidity tends to be lowered. Therefore, by adding a transition metal other than copper to these three components, it is possible to further improve the catalyst activity, reduce the decrease in activity over time, and prevent the catalyst fluidity from decreasing due to the increase in the amount of impregnation.
[0026]
Further, the impregnation method of the solution in which the transition metal other than copper is dissolved is a pre-impregnation method, a simultaneous impregnation method, and a post-impregnation method performed before, simultaneously with, and after the impregnation of the solution containing copper, alkali metal, and rare earth metal. The impregnation method is not particularly limited.
[0027]
As the copper component, specifically, for example, copper nitrate, copper sulfate, copper chloride, and copper oxide can be used, and alkali metals, rare earth metals, and transition metals other than copper are similarly nitrates and sulfates of these metals. , Chlorides and oxides can be used. Specific examples of the alkali metal component include potassium nitrate, potassium sulfate, potassium chloride, sodium nitrate, sodium sulfate, sodium chloride, sodium oxide and the like. Examples of rare earth metal salts include nitrates such as lanthanum, praseodymium, neodymium, promethium, samarium, europium, sulfates, halides, oxides, etc. Among them, lanthanum salts are preferred. Examples of transition metals other than copper include nitrates such as titanium, vanadium, manganese, iron, cobalt, and nickel, sulfates, halides, oxides, and the like. Among these, cobalt salts are preferable.
[0028]
The higher the concentration of copper, alkali metal, rare earth metal, and transition metal other than copper, the higher the effect, but the atomic ratio with respect to chromium of the catalyst mainly composed of chromium oxide is copper = 0.01 to 0.00. The ranges of 3, potassium = 0.005-0.2, lanthanum = 0.01-0.3, cobalt = 0.01-0.3 are preferred.
[0029]
【Example】
Next, the method of the present invention will be described in more detail with reference to examples.
Example 1
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. Waste hydrogen chloride gas was allowed to flow into the fluidized bed at 334 ml / min and oxygen at 167 ml / min, and the outside of the reaction tube was heated to an internal temperature of 380 ° C. in an electric furnace for reaction. The oxygen / hydrogen chloride molar ratio is ½, and the oxygen excess is 100%.
The conversion rate of hydrogen chloride on the third day from the start of the reaction was 73%. On the 30th day from the start of the reaction, the conversion was 67%, and on the 65th day, the conversion decreased to 55%.
Cu (NO 3 ) 2 .3H 2 O 3.78 g, KNO 3 1.56 g, La (NO 3 ) 2 .6H 2 O 5.32 g, and Co (NO 3 ) 2 .6H 2 O 5.92 g were added to this waste catalyst. After simultaneously impregnating 27 ml of the dissolved aqueous solution, it was baked at 420 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as described above.
The conversion rate of hydrogen chloride on the third day from the start of the reaction was 78%. On the 30th day from the start of the reaction, the conversion was 70%, and on the 65th day, the conversion was 68%, indicating an activity and life equal to or greater than that of the new catalyst.
[0030]
Example 2
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. The waste catalyst obtained by reacting in the same manner as in Example 1 was extracted, and Cu (NO 3 ) 2 .3H 2 O 3.78 g, KNO 3 1.56 g, La (NO 3 ) 2 · 6H 2 O 5 were extracted from this waste catalyst. It was impregnated with 25 ml of an aqueous solution in which .32 g and 2.96 g of Co (NO 3 ) 2 .6H 2 O were dissolved, and calcined at 420 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as described above.
The conversion rate of hydrogen chloride on the third day from the start of the reaction was 77%. On the 30th day from the start of the reaction, the conversion was 68%, and on the 65th day, the conversion was 62%, indicating an activity and life equal to or greater than that of the new catalyst.
[0031]
Comparative Example 1
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. The waste catalyst obtained by reacting in the same manner as in Example 1 was extracted, and 3.78 g of Cu (NO 3 ) 2 .3H 2 O, 1.56 g of KNO 3, 5.32 g of La (NO 3 ) 2 .6H 2 O, After impregnation in 27 ml of the dissolved aqueous solution, it was calcined at 420 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as described above.
The conversion rate of hydrogen chloride on the 3rd day of the reaction was 75%, the conversion rate was 66% on the 30th day of the reaction, and the conversion rate was 56% on the 65th day.
[0032]
Comparative Example 2
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. The waste catalyst obtained by the reaction in the same manner as in Example 1 was extracted, impregnated with 27 ml of an aqueous solution in which 5.92 g of Co (NO 3 ) 2 .6H 2 O was dissolved in this waste catalyst, and then calcined at 420 ° C. for 5 hours. . 40 g of this regenerated catalyst was reacted in the same manner as described above.
The conversion rate of hydrogen chloride on the third day from the start of the reaction was 55%, and the conversion rate was not improved.
[0033]
Example 3
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. The waste catalyst obtained by reacting in the same manner as in Example 1 was extracted, and Cu (NO 3 ) 2 .3H 2 O 3.78 g, KNO 3 1.56 g, La (NO 3 ) 2 · 6H 2 O 5 were extracted from this waste catalyst. After impregnating with 20 ml of an aqueous solution in which .32 g was dissolved, it was calcined at 420 ° C. for 5 hours. Thereafter, the mixture was impregnated with 7.4 ml of an aqueous solution in which 5.92 g of Co (NO 3 ) 2 .6H 2 O was dissolved, and calcined at 420 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as described above.
The conversion rate of hydrogen chloride on the third day from the start of the reaction was 78%. On the 30th day from the start of the reaction, the conversion was 70%, and on the 65th day, the conversion was 68%, indicating an activity and life equal to or greater than that of the new catalyst.
[0034]
Example 4
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. The waste catalyst obtained by the reaction in the same manner as in Example 1 was extracted, and 15.17 g of Cu (NO 3 ) 2 .3H 2 O, 6.24 g of KNO 3 , La (NO 3 ) 2 .6H 2 O 10 was extracted from this waste catalyst. It was impregnated with 50.0 ml of an aqueous solution in which .64 g and 5.92 g of Co (NO 3 ) 2 .6H 2 O were dissolved, and calcined at 420 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as described above.
The conversion rate of hydrogen chloride on the third day from the start of the reaction was 80%. On the 30th day from the start of the reaction, the conversion rate was 72%, and on the 65th day, the conversion rate was 70%.
[0035]
Comparative Example 3
A glass fluidized bed reactor having an inner diameter of 1 inch was charged with 40 g of a fine spherical fluidized bed catalyst composed of 75% by weight of chromia and 25% by weight of silica and having an average particle diameter of 60 μm. The waste catalyst obtained by the reaction in the same manner as in Example 1 was extracted, and 15.17 g of Cu (NO 3 ) 2 .3H 2 O, 6.24 g of KNO 3 , La (NO 3 ) 2 .6H 2 O 10 was extracted from this waste catalyst. After impregnating 50.0 ml of an aqueous solution in which .64 g was dissolved, it was calcined at 420 ° C. for 5 hours. 40 g of this regenerated catalyst was reacted in the same manner as described above.
On the third day from the start of the reaction, the conversion rate of hydrogen chloride was 79%. On the 30th day from the start of the reaction, the conversion rate was 71%, and on the 65th day, the conversion rate was 69%, indicating an activity and life equal to or higher than that of the new catalyst, but the catalyst fluidity tends to decrease slightly from the 30th day onward. It was observed.
[0036]
【The invention's effect】
According to the method of the present invention, a catalyst having a conventionally known chromium oxide as a main component, which has been used for a long time in an oxidation reaction of hydrogen chloride and has a reduced activity, is made of copper, an alkali metal, a rare earth metal, and a transition metal other than copper. It can be activated and regenerated by impregnating the solution and baking at a temperature of 800 ° C. or lower. The regenerated catalyst thus obtained has high activity, good catalyst fluidity, and has the same performance as the new catalyst in a long-term life test.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17962396A JP3788530B2 (en) | 1996-07-09 | 1996-07-09 | Catalyst regeneration method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17962396A JP3788530B2 (en) | 1996-07-09 | 1996-07-09 | Catalyst regeneration method |
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| Publication Number | Publication Date |
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| JPH1015389A JPH1015389A (en) | 1998-01-20 |
| JP3788530B2 true JP3788530B2 (en) | 2006-06-21 |
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| CN1262472C (en) * | 1999-01-22 | 2006-07-05 | 住友化学工业株式会社 | Method for producing chlorine |
| AU2000230735A1 (en) * | 2000-01-19 | 2001-08-27 | Sumitomo Chemical Company Limited | Method for producing chlorine |
| JP5368883B2 (en) * | 2009-05-29 | 2013-12-18 | 住友化学株式会社 | Method for activating catalyst for chlorine production and method for producing chlorine |
| JP5388974B2 (en) * | 2010-09-17 | 2014-01-15 | 三井化学株式会社 | Method for producing regenerated catalyst for chlorine production, method for regenerating degraded catalyst, method for producing chlorine, and method for maintaining activity of catalyst for chlorine production |
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1996
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