JP3544603B2

JP3544603B2 - Hydrorefining method of hydrocarbon oil

Info

Publication number: JP3544603B2
Application number: JP23911796A
Authority: JP
Inventors: 秀雄田中
Original assignee: Petroleum Energy Center PEC; Japan Energy Corp
Current assignee: Japan Petroleum Energy Center JPEC; Eneos Corp
Priority date: 1996-09-10
Filing date: 1996-09-10
Publication date: 2004-07-21
Anticipated expiration: 2016-09-10
Also published as: JPH1088152A

Description

【０００１】
【発明の属する技術分野】
本発明は、炭化水素油、特には、熱分解油または接触分解油等の不飽和分、窒素分や芳香族分に富む炭化水素油を含むナフサ留分、灯油留分、軽油留分または減圧軽油留分等の炭化水素油から硫黄分や窒素分等の不純物を低減させる水素化精製方法に関する。
【０００２】
【従来の技術】
最近、環境問題への配慮から、各種石油製品中の硫黄分や窒素分等の不純物を高度に除去することが求められており、各種の石油留分において、過酷な条件での水素化精製の検討が進められている。かかる石油留分の中で熱分解油または接触分解油等は不飽和分を多く含んでおり、これらの炭化水素油を過酷な条件で水素化精製を行うと、炭化水素油がアスファルテン分を含まなくても、コークスの生成が顕著となり、触媒の不活性化を増長させる。
【０００３】
そのため、この種の炭化水素油の水素化精製においては、このようなコークスの生成による触媒の劣化を抑制し、触媒寿命を延長させるための種々の方法が試みられている。そのような水素化精製方法の例として、反応器の上部区域に周期律表第ＶＩＢ族、第ＶＩＩＩ族の金属、金属酸化物、金属硫化物のうちから選ばれた成分と燐の酸化物および／または硫化物とを含む水素化精製触媒を、下部区域には周期律表ＶＩＢ族、第ＶＩＩＩ族の金属、金属酸化物、金属硫化物のうちから選ばれた成分と燐含有量が０．５重量％未満である水素化精製触媒を使用する方法（特開昭６１−２６６４９０号公報）が提案されている。この方法では、下部区域に使用する触媒には、燐を実質的に含まないものを用いることが特徴として挙げられ、その理由として燐を実質的に含有しない触媒を用いることによってコークス生成による触媒の不活性化が起こりにくことを挙げている。
【０００４】
しかし、このような触媒を用いた水素化精製方法では、下部区域での脱硫活性、脱窒素活性および水素付加活性が不十分で、精製油中の硫黄分、窒素分や不安定性成分等の不純物が満足できる程度に低減されず、特に脱窒素活性が低く、それ自身の品質が劣るのみならず、これが原因で、製品の安定性等を悪化させるという問題もあった。
【０００５】
【発明が解決しようとする課題】
本発明は上記課題を解決するもので、本発明の目的はコークスの生成を抑制し、触媒寿命を延長させるとともに、精製油中の硫黄分や窒素分等を十分に低減させて安定性等に優れた製品としうる精製油を得ることができる水素化精製方法を提供することにある。
【０００６】
【課題を解決するための手段】
本発明者は、上記課題を解決するために、鋭意研究を進めた結果、驚くべきことに、炭化水素油を、先ず、モリブデンとニッケルおよびリンとを含有する第１の触媒と接触させ、ついで、モリブデンとコバルトおよびリンとを含有する第２の触媒と接触させると、それぞれ単独で触媒を用いる方法やその他の組合せによる方法に比べて、触媒の寿命を長く保つことができ、しかも高い脱硫率や脱窒素率等が得られることを見いだした。
【０００７】
またこれを、第２の触媒からリンを除いた触媒を用いる方法と比較すると、高い脱硫率や脱窒素率等が得られるのみならず、リンを含有させても、コークスの生成による触媒の劣化は少なく、触媒寿命の点でも充分満足すべきものが得られることがわかった。
【０００８】
本発明はかかる知見に基づきなされたもので、本発明は、炭化水素油を、水素加圧下に、モリブデンを金属換算で８〜１６重量％、ニッケルを金属換算で１〜６重量％およびリンを元素換算で１〜６重量％含有する第１の水素化精製触媒と接触させ、次いで、モリブデンを金属換算で８〜１６重量％、コバルトを金属換算で１〜６重量％およびリンを元素換算で１〜６重量％含有する第２の水素化精製触媒と接触させることからなる炭化水素油の水素化精製方法である。
【０００９】
【発明の実施の形態】
本発明では適用できる炭化水素油に特に制限はなく、各種の石油留分、常圧蒸留残渣油、減圧蒸留残渣油、あるいはシェールオイル、コールタール油、石油液化油から得られる各種留分や残渣油等のいずれも支障なく用いることができるが、ナフサ留分、灯油留分、軽油留分または減圧軽油留分等が好適である。特には、原油を蒸留して得られるいわゆる直留油よりも多量の窒素化合物や不飽和化合物を含有する熱分解油または接触分解油を含む前記の各種留分を用いることが、本発明の効果を顕著に発揮できるため好ましい。本発明の方法においては、窒素化合物をコーク前駆体とすることなしに除去できるため、特には、熱分解油または接触分解油を含む留分で、灯油留分にあっては４０ｐｐｍ以上の、軽油留分にあっては３００ｐｐｍ以上の、窒素分を含むものが、さらに好適である。
【００１０】
本発明の第１の水素化精製触媒としては、モリブデンとニッケルおよびリンを含有する慣用の水素化精製触媒を用いることができる。この触媒は、一般に、モリブデンとニッケルの金属、金属酸化物、金属硫化物および／またはその混合物のうちから選択された成分および酸化リンおよび／または硫化リン成分とからなり、通常はこれを担体に担持または混練させて使用する。
【００１１】
触媒（担体を含む）中のモリブデンまたはモリブデン化合物の含有量は、水素化精製活性を高く保持するため、金属換算で８〜１６重量％とする。また、同様に、触媒中のニッケル含有量は金属換算で１〜６重量％、好ましくは２〜４重量％、リンの含有量は元素換算で１〜６重量％、好ましくは２〜４重量％である。
【００１２】
また、この場合の担体としては、一般の触媒担体として用いられている多孔質の無機酸化物から調製されるのであれば何れでも支障無く、例えば、周期律表第２、第４、第１３、第１４族元素の酸化物からなるものが挙げられる。特に、シリカ、アルミナ、マグネシア、ジルコニア、ボリア、カルシア等の酸化物の少なくとも１種類を使用できる。このうち、アルミナ（α、γ、δ、η、χ等の各結晶構造）、シリカ−アルミナ、シリカ、アルミナ−マグネシア、シリカ−マグネシア、アルミナ−シリカ−マグネシア等からなるものが好適に用いられる。
【００１３】
この触媒は、一般には、水和アルミナ、あるいはこれに所望により、シリカ、マグネシア、カルシア、チタニア、酸化亜鉛等を、水、および硝酸等の解膠剤とともに混練した後、成形、乾燥、焼成して担体として、これに周期律表第６族金属成分とニッケルおよびリンを、通常用いられる含浸法、例えば、ｐｏｒｅ−ｆｉｌｌｉｎｇ法、加熱含浸法、真空含浸法や浸漬法等で担持するか、あるいは前記アルミナ等の混練の際に、周期律表第６族金属成分とニッケルおよびリンを添加して混練する方法で調製することができる。
【００１４】
この触媒は、窒素吸脱着法により測定した比表面積が５０〜５００ｍ^２／ｇ、より好ましくは１００〜３００ｍ^２／ｇ、平均細孔容積が０．１〜１ｃｃ／ｇ、より好ましくは０．３〜０．７ｃｃ／ｇ、平均細孔径が２０〜２００オングストローム、より好ましくは５０〜１５０オングストロームの範囲のものが特に好ましい。また、触媒の形状は、球状、円柱状、三葉型または四葉型等のいかなる形状でも使用に支障はない。
【００１５】
また、この第１の水素化精製触媒を用いる精製反応は、反応温度が２００〜５００℃、好ましくは３００〜４５０℃、反応圧力が、水素圧として２０〜２５０ｋｇ／ｃｍ^２、好ましくは３０〜２００ｋｇ／ｃｍ^２、液空間速度（ＬＨＳＶ）が０．０５〜７ｈｒ^−１、好ましくは０．１〜４ｈｒ^−１、水素ガスと原料油の供給割合（Ｈ_２／Ｏｉｌ）が１００〜３０００Ｎｍ^３／ｋｌ、好ましくは１６０〜１５００Ｎｍ^３／ｋｌの条件下で、炭化水素油と接触させることが好ましい。
【００１６】
一方、第２の水素化精製触媒としては、モリブデンとコバルトおよびリンを含有する慣用の水素化精製触媒を用いることができる。この触媒も、第１の水素化精製触媒と同様に、一般に、モリブデンとコバルトの金属、金属酸化物、金属硫化物および／またはその混合物のうちから選択された成分および酸化リン酸および／または硫化リン成分とからなり、これを担体に担持させたものである。
【００１７】
第２の水素化精製触媒におけるモリブデンまたはモリブデン化合物の含有量は、水素化精製活性を高く保持するため、触媒中、金属換算で８〜１６重量％であり、同様に、コバルト含有量は金属換算で１〜６重量％、好ましくは２〜４重量％である。
【００１８】
また本発明ではは第２触媒においてもリンは必須成分であり、その含有量は元素換算で１〜６重量％、好ましくは１〜３重量％である。リン含有量がこの範囲よりも少ないと水素化精製活性が不充分であり、一方これよりも多くなると、コークスの生成による触媒の不活性化が起こりやすくなる。
【００１９】
この触媒の担体、触媒の調製法および表面積や細孔容積等の物性、形状等は、上記第１の触媒と同じとすることができる。
【００２０】
本発明においては、炭化水素油を、水素加圧下に上記第１の水素化精製触媒と接触させ、次いで、第２の水素化精製触媒と接触させることにより炭化水素油を水素化精製するので、原料炭化水素油を流通させる反応装置の上流に第１の触媒層を、下流に第２の触媒層を配置した反応装置であれば、いずれの形式のものも使用することができ、例えば１つの反応装置中に触媒層を２段もうけたもの、あるいは一方に第１の触媒を、他方に第２の触媒を充填した２つの反応装置を直列に連結し原料油を流通させる方法等を用いることができる。
【００２１】
この場合、第２の水素化精製触媒は、上記第１の水素化精製触媒の条件と同様の条件で接触させることができ、特には、第１の水素化精製触媒と接触して得られた精製油から水素等の分離を行うことなく、そのまま、全留分を第２の水素化精製触媒と接触させることが好ましい。
【００２２】
また、本発明における第１と第２の水素化精製触媒量の割合は、上記第１の水素化精製触媒量を全触媒容量に占める割合の１５〜８５％、好ましくは３０〜７０％とすることが好ましい。第２の水素化精製触媒の使用割合が少ないと、水素化精製の活性が低下する傾向があり、また第１の水素化精製触媒の使用割合が少ないと、触媒寿命が低下する。
【００２３】
【実施例】
（触媒の調製）
ヘプタモリブデン酸アンモニウム、硝酸ニッケル、リン酸の水溶液を、γ−アルミナに含浸担持して、モリブデン１２重量％、ニッケル３重量％、リン２．５重量％を含む触媒Ａを調製した。この触媒は、比表面積が１７０ｍ^２／ｇ、平均細孔容積が０．３９ｃｃ／ｇ、平均細孔径が７９オングストロームであった。
【００２４】
また、硝酸ニッケルの代わりに硝酸コバルトを使用して、γ−アルミナに含浸担持してモリブデン１１重量％、コバルト３重量％、リン２重量％を含む触媒Ｂを調製した。この触媒は、比表面積が１８０ｍ^２／ｇ、平均細孔容積が０．４０ｃｃ／ｇ、平均細孔径が８０オングストームであった。
【００２５】
比較のため、ヘプタモリブデン酸アンモニウムおよび硝酸コバルトのみで、リンを含まない含浸液を用いて上記と同様にして、モリブデン１１重量％、コバルト３重量％を含む触媒Ｃを調製した。この触媒は、比表面積が１８０ｍ^２／ｇ、平均細孔容積０．４ｃｃ／ｇ、平均細孔径が８０オングストロームであった。
【００２６】
［実施例１］（初期活性試験）
反応器容積１００ｍｌの高圧流通式反応装置を使用して、反応器上流に触媒Ａを５０ｍｌ、反応器下流に触媒Ｂを５０ｍｌ充填した。これに、熱分解コーカ軽油６０容量％と直留軽油４０容量％とを混合して得られた原料油Ｉを用いて、水素圧力５０ｋｇ／ｃｍ^２、反応温度３５０℃、液空間速度（ＬＨＳＶ）２ｈ^−１、Ｈ_２／Ｏｉｌ比２５０ｌ／ｌの条件下に水素化精製を行った。原料油Ｉの性状は表１のとおりである。
【００２７】
【表１】

【００２８】
実施例１と同じ反応器に触媒Ａのみを１００ｍｌ充填した場合（比較例１）、触媒Ｂのみを１００ｍｌ充填した場合（比較例２）、反応器上流に触媒Ｂを５０ｍｌ、反応器下流に触媒Ａを５０ｍｌ充填した場合（比較例３）、反応器上流に触媒Ａを５０ｍｌ、反応器下流に触媒Ｃを５０ｍｌ充填した場合（比較例４）について、それぞれ実施例１と同じ条件で水素化精製を行った。
【００２９】
得られた精製油中の硫黄分および窒素分を測定し、硫黄分の測定値から反応速度次数を１．５として脱硫反応速度定数を、また窒素分の測定値から反応速度次数を１．０として脱窒素反応速度定数を求め、触媒Ａのみを充填した比較例１の場合の脱硫および脱窒素の反応速度定数を１００とした初期活性の相対比較値を求めた。これらの結果を表２に示した。
【００３０】
【表２】

【００３１】
表２の結果から、触媒ＡとＢを５０／５０で充填した本発明の実施例１のものおよび触媒Ｂのみを充填した比較例２のものが優れた初期脱硫活性を示し、また脱窒素活性についても、特に下流にリンを含まない触媒Ｃを用いた比較例４の触媒に比べて、精製油中の窒素分が大幅に減少し、製品とした場合、安定性に優れていることが分かる。
【００３２】
そこで次に、初期脱硫活性及び脱窒素活性が優れている上記実施例１と比較例２の触媒を充填したケースについて、触媒寿命試験を行った。
【００３３】
［実施例２、比較例５］（寿命試験）
実施例１と同じ反応器に実施例１と同様に上流に触媒Ａを５０ｍｌ、反応器下流に触媒Ｂを５０ｍｌ充填したもの（実施例２）および比較例２と同様に触媒Ｂのみを１００ｍｌ充填したもの（比較例５）について、コーカ重質軽油３０容量％と減圧軽油７０重量％とを混合して得られた原料油ＩＩを用いて、水素圧力７０ｋｇ／ｃｍ^２、反応温度４００℃、液空間速度（ＬＨＳＶ）４ｈ^−１、Ｈ_２／Ｏｉｌ比２９０ｌ／ｌの加速された反応条件下に、水素化精製を行った。原料油ＩＩの性状は表１のとおりである。
【００３４】
精製油中の硫黄分を経時的に測定して、劣化速度定数を求めた。この劣化速度定数は、脱硫反応劣化速度を反応次数１．３次で計算して得られた反応速度定数（ｋ）と運転時間（ｔ）との間に得られる関係、ｋ＝Ａ・ｅｘｐ（−α・ｔ）におけるαの値として求められるものである。また、脱硫反応の活性化エネルギーを３２ｋｃａｌ／ｍｏｌとして、前記関係式より運転初期反応温度（℃）を求め、これらの結果を表３に示した。
【００３５】
【表３】

【００３６】
表３の結果から明らかなように、初期脱硫活性及び脱窒素活性においては本発明の触媒とほぼ同等の優れた結果を示す触媒Ｂのみを充填した比較例５のものも、コークスの生成により触媒の劣化が起こり、触媒寿命の点では充分とは言えないのに対し、本発明の触媒は、触媒Ｂのみを用いた場合に較べて、コークスの生成が抑制され、約２倍の触媒寿命を有する。
【００３７】
以上の結果より、第１の水素化精製触媒としてモリブデンとニッケルおよびリンを含有する触媒を用い、第２の水素化精製触媒として、モリブデンとコバルトおよびリンを触媒を用いて、水素化精製を行うと、運転初期の反応温度は脱硫活性の高い触媒Ｂのみを使用した場合とほぼ同等の性能が得られる上に、触媒寿命が長く、炭化水素油の水素化精製触媒として優れたものであることが分かる。
【００３８】
【発明の効果】
本発明の水素化精製方法は、コークスの生成を抑制し、触媒寿命を延長させるとともに、精製油中の硫黄分や窒素分、不安定性成分を十分に低減させて安定性等に優れた製品としうる精製油を得ることができるという格別の効果を奏する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrocarbon oil, in particular, a naphtha fraction, a kerosene fraction, a gas oil fraction or a vacuum containing unsaturated components such as pyrolysis oil or catalytic cracking oil, and hydrocarbon oils rich in nitrogen and aromatics. The present invention relates to a hydrorefining method for reducing impurities such as sulfur and nitrogen from hydrocarbon oils such as gas oil fractions.
[0002]
[Prior art]
Recently, due to environmental concerns, it has been required to highly remove impurities such as sulfur and nitrogen in various petroleum products. Examination is underway. Among such petroleum fractions, pyrolysis oil or catalytic cracking oil contains a large amount of unsaturated components, and when these hydrocarbon oils are hydrorefined under severe conditions, the hydrocarbon oils contain asphaltenes. Even without it, the production of coke becomes significant and prolongs the deactivation of the catalyst.
[0003]
Therefore, in the hydrorefining of this kind of hydrocarbon oil, various methods for suppressing the deterioration of the catalyst due to the generation of coke and extending the life of the catalyst have been tried. Examples of such hydrorefining processes include, in the upper section of the reactor, a component selected from Group VIB, Group VIII metals, metal oxides, metal sulfides and oxides of phosphorus and And / or a sulfide containing a component selected from metals, metal oxides and metal sulfides of Group VIB and Group VIII of the periodic table in the lower section and a phosphorus content of 0. A method using a hydrorefining catalyst of less than 5% by weight (JP-A-61-266490) has been proposed. This method is characterized in that the catalyst used in the lower section is substantially free of phosphorus, and the reason for this is that the use of a catalyst substantially free of phosphorus allows the catalyst to be produced by coke formation. It states that inactivation is unlikely to occur.
[0004]
However, in the hydrorefining method using such a catalyst, the desulfurization activity, denitrification activity, and hydrogenation activity in the lower section are insufficient, and impurities such as sulfur, nitrogen, and unstable components in the refined oil. Is not reduced to a satisfactory degree, and in particular, the denitrification activity is low, and not only is the quality of the product itself inferior, but also there is a problem that the stability of the product is deteriorated due to this.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above problems, and an object of the present invention is to suppress coke generation, prolong the catalyst life, and sufficiently reduce the sulfur content and the nitrogen content in refined oil to improve stability and the like. An object of the present invention is to provide a hydrorefining method capable of obtaining a refined oil which can be used as an excellent product.
[0006]
[Means for Solving the Problems]
The present inventor has made intensive studies to solve the above-mentioned problems, and as a result, surprisingly, the hydrocarbon oil was first brought into contact with a first catalyst containing molybdenum , nickel and phosphorus, and then When the catalyst is brought into contact with a second catalyst containing molybdenum , cobalt and phosphorus, the life of the catalyst can be kept longer as compared with a method using a catalyst alone or a method using other combinations, and a high desulfurization rate can be obtained. And a denitrification rate were obtained.
[0007]
When this is compared with the method using a catalyst in which phosphorus is removed from the second catalyst, not only a high desulfurization rate and a denitrification rate can be obtained, but also the deterioration of the catalyst due to the generation of coke even when phosphorus is contained. It was found that the catalyst was satisfactory in terms of catalyst life.
[0008]
The present invention has been made on the basis of such knowledge, and the present invention relates to a method of producing a hydrocarbon oil under a hydrogen pressure of 8 to 16 % by weight of molybdenum in terms of metal, 1 to 6% by weight of nickel in terms of metal and phosphorus. It is brought into contact with a first hydrotreating catalyst containing 1 to 6% by weight in terms of element, and then 8 to 16 % by weight of molybdenum in terms of metal, 1 to 6% by weight of cobalt in terms of metal and phosphorus in terms of element. A method for hydrorefining hydrocarbon oils, comprising contacting a second hydrorefining catalyst containing 1 to 6% by weight.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
There is no particular limitation on the hydrocarbon oils applicable in the present invention, and various petroleum fractions, atmospheric distillation residue oil, vacuum distillation residue oil, or shale oil, coal tar oil, various fractions and residues obtained from petroleum liquefied oil Any of oil and the like can be used without any problem, but a naphtha fraction, a kerosene fraction, a light oil fraction or a reduced pressure gas oil fraction is preferred. In particular, the effect of the present invention is to use the above-mentioned various fractions containing pyrolysis oil or catalytic cracking oil containing a larger amount of nitrogen compounds and unsaturated compounds than so-called straight run oil obtained by distilling crude oil. Is remarkably exhibited, which is preferable. In the method of the present invention, since the nitrogen compound can be removed without using it as a coke precursor, it is particularly a fraction containing a pyrolysis oil or a catalytic cracking oil, and in a kerosene fraction, at least 40 ppm of light oil, It is more preferable that the fraction contains 300 ppm or more of nitrogen.
[0010]
As the first hydrorefining catalyst of the present invention, a conventional hydrorefining catalyst containing molybdenum , nickel and phosphorus can be used. This catalyst generally comprises a component selected from molybdenum and nickel metals, metal oxides, metal sulfides and / or mixtures thereof, and a phosphorus oxide and / or phosphorus sulfide component, which is usually used as a support. Used by supporting or kneading.
[0011]
The content of molybdenum or molybdenum compounds in catalysts (including carrier), in order to maintain high hydrotreating activity, and 8-16% by weight in terms of metal. Similarly, the nickel content in the catalyst is 1 to 6% by weight, preferably 2 to 4% by weight in terms of metal, and the phosphorus content is 1 to 6% by weight, preferably 2 to 4% by weight in terms of element. It is.
[0012]
In addition, as the carrier in this case, any material can be used as long as it is prepared from a porous inorganic oxide used as a general catalyst carrier. For example, the second, fourth, thirteenth, and thirteenth periodic tables can be used. Examples include oxides of Group 14 elements. In particular, at least one of oxides such as silica, alumina, magnesia, zirconia, boria, and calcia can be used. Among them, those composed of alumina (each crystal structure such as α, γ, δ, η, χ), silica-alumina, silica, alumina-magnesia, silica-magnesia, alumina-silica-magnesia and the like are preferably used.
[0013]
This catalyst is generally hydrated alumina, or, if desired, silica, magnesia, calcia, titania, zinc oxide, etc., mixed with water and a peptizer such as nitric acid, then molded, dried and calcined. As a carrier, a metal component of Group 6 of the periodic table and nickel and phosphorus are supported on the carrier by a commonly used impregnation method, for example, a pore-filling method, a heat impregnation method, a vacuum impregnation method or an immersion method, or When kneading the alumina or the like, it can be prepared by adding and kneading a metal component of Group 6 of the periodic table with nickel and phosphorus.
[0014]
This catalyst has a specific surface area measured by a nitrogen adsorption / desorption method of 50 to 500 m ² / g, more preferably 100 to 300 m ² / g, and an average pore volume of 0.1 to 1 cc / g, more preferably 0.3 to 1 cc / g. Particularly, those having an average pore diameter of 20 to 200 angstroms, more preferably 50 to 150 angstroms, are particularly preferable. Further, the catalyst may be used in any shape such as a spherical shape, a cylindrical shape, a three-lobe shape, a four-lobe shape, or the like.
[0015]
The purification reaction using the first hydrorefining catalyst has a reaction temperature of 200 to 500 ° C., preferably 300 to 450 ° C., and a reaction pressure of 20 to 250 kg / cm ² , preferably 30 to ²⁰⁰ kg as a hydrogen pressure. / Cm ² , a liquid hourly space velocity (LHSV) of 0.05 to 7 hr ⁻¹ , preferably 0.1 to 4 hr ⁻¹ , and a supply ratio (H ₂ / Oil) of hydrogen gas and feed oil of 100 to 3000 Nm ³ / kl. , Preferably under the conditions of 160 to 1500 Nm ³ / kl.
[0016]
On the other hand, as the second hydrorefining catalyst, a conventional hydrorefining catalyst containing molybdenum , cobalt and phosphorus can be used. This catalyst, as well as the first hydrorefining catalyst, is generally a component selected from molybdenum and cobalt metals, metal oxides, metal sulfides and / or mixtures thereof, and phosphoric oxide and / or sulfide. It consists of a phosphorus component, which is supported on a carrier.
[0017]
The content of molybdenum or a molybdenum compound in the second hydrorefining catalyst is 8 to 16% by weight in terms of metal in the catalyst in order to maintain high hydrorefining activity. 1 to 6% by weight, preferably 2 to 4% by weight.
[0018]
In the present invention, phosphorus is also an essential component in the second catalyst, and its content is 1 to 6% by weight, preferably 1 to 3% by weight in terms of element. If the phosphorus content is less than this range, the hydrorefining activity will be insufficient, while if it is greater than this, the catalyst will be more likely to be deactivated due to the formation of coke.
[0019]
The carrier of the catalyst, the preparation method of the catalyst, and the physical properties such as surface area and pore volume, shape and the like can be the same as those of the first catalyst.
[0020]
In the present invention, the hydrocarbon oil is contacted with the first hydrorefining catalyst under hydrogen pressure and then contacted with the second hydrorefining catalyst to hydrorefine the hydrocarbon oil. Any type of reactor can be used as long as it has a first catalyst layer upstream of the reactor through which the raw hydrocarbon oil flows, and a second catalyst layer downstream thereof. A method in which two stages of catalyst layers are provided in a reactor, or a method in which two reactors filled with a first catalyst on one side and a second catalyst on the other side are connected in series and a feed oil is passed is used. Can be.
[0021]
In this case, the second hydrorefining catalyst can be brought into contact under the same conditions as those of the first hydrotreating catalyst, and in particular, the catalyst obtained by contacting the first hydrotreating catalyst is obtained. It is preferable that the entire fraction is brought into contact with the second hydrorefining catalyst without separating hydrogen or the like from the refined oil.
[0022]
The ratio of the first and second hydrotreating catalysts in the present invention is 15 to 85%, preferably 30 to 70% of the ratio of the first hydrotreating catalyst to the total catalyst capacity. Is preferred. If the use ratio of the second hydrorefining catalyst is small, the activity of hydrorefining tends to decrease, and if the use ratio of the first hydrorefining catalyst is small, the catalyst life is reduced.
[0023]
【Example】
(Preparation of catalyst)
An aqueous solution of ammonium heptamolybdate, nickel nitrate, and phosphoric acid was impregnated and supported on γ-alumina to prepare Catalyst A containing 12% by weight of molybdenum, 3% by weight of nickel, and 2.5% by weight of phosphorus. This catalyst had a specific surface area of 170 m ² / g, an average pore volume of 0.39 cc / g, and an average pore diameter of 79 Å.
[0024]
A catalyst B containing 11% by weight of molybdenum, 3% by weight of cobalt, and 2% by weight of phosphorus was prepared by impregnating and supporting γ-alumina using cobalt nitrate instead of nickel nitrate. This catalyst had a specific surface area of 180 m ² / g, an average pore volume of 0.40 cc / g, and an average pore diameter of 80 Å.
[0025]
For comparison, a catalyst C containing 11% by weight of molybdenum and 3% by weight of cobalt was prepared in the same manner as described above using only an ammonium heptamolybdate and cobalt nitrate and using an impregnating liquid not containing phosphorus. This catalyst had a specific surface area of 180 m ² / g, an average pore volume of 0.4 cc / g, and an average pore diameter of 80 Å.
[0026]
[Example 1] (Initial activity test)
Using a high-pressure flow reactor with a reactor volume of 100 ml, 50 ml of catalyst A was charged upstream of the reactor, and 50 ml of catalyst B was charged downstream of the reactor. Then, using a feed oil I obtained by mixing 60% by volume of pyrolysis coker gas oil and 40% by volume of straight run gas oil, a hydrogen pressure of 50 kg / cm ² , a reaction temperature of 350 ° C., and a liquid hourly space velocity (LHSV) Hydrorefining was performed under the conditions of 2h ^-1 and an H ₂ / Oil ratio of 250 l / l. Table 1 shows the properties of the feedstock I.
[0027]
[Table 1]

[0028]
When the same reactor as in Example 1 was filled with only 100 ml of the catalyst A (Comparative Example 1), when only 100 ml of the catalyst B was filled (Comparative Example 2), 50 ml of the catalyst B was upstream of the reactor and 50 ml of the catalyst was downstream of the reactor. When A was filled with 50 ml (Comparative Example 3), 50 ml of the catalyst A was charged upstream of the reactor, and 50 ml of the catalyst C was charged downstream of the reactor (Comparative Example 4). Was done.
[0029]
The sulfur content and the nitrogen content in the obtained refined oil were measured, the desulfurization reaction rate constant was determined by setting the reaction rate order to 1.5 from the measured value of the sulfur content, and the reaction rate order was set to 1.0 from the measured value of the nitrogen content. The denitrification reaction rate constant was determined, and a relative comparison value of the initial activity was determined with the reaction rate constant for desulfurization and denitrification in Comparative Example 1 in which only the catalyst A was charged as 100. Table 2 shows the results.
[0030]
[Table 2]

[0031]
From the results shown in Table 2, those of Example 1 of the present invention in which the catalysts A and B were charged at 50/50 and those of Comparative Example 2 in which only the catalyst B was charged showed excellent initial desulfurization activity, Also, as compared with the catalyst of Comparative Example 4 using the catalyst C containing no phosphorus downstream, the nitrogen content in the refined oil was greatly reduced, and it was found that the product was excellent in stability when used as a product. .
[0032]
Therefore, next, a catalyst life test was performed on the case where the catalysts of Example 1 and Comparative Example 2 having excellent initial desulfurization activity and denitrification activity were filled.
[0033]
[Example 2, Comparative Example 5] (Life test)
The same reactor as in Example 1 was charged with 50 ml of catalyst A upstream and 50 ml of catalyst B downstream of the reactor as in Example 1 (Example 2), and as in Comparative Example 2, only 100 ml of catalyst B was charged. (Comparative Example 5), using a feed oil II obtained by mixing 30% by volume of coker heavy gas oil and 70% by weight of reduced pressure gas oil, with a hydrogen pressure of 70 kg / cm ² , a reaction temperature of 400 ° C., and a liquid space velocity ^(LHSV) 4h _-1, the accelerated reaction conditions of H 2 / Oil ratio 290 l / l, was hydrorefining. The properties of the feedstock II are as shown in Table 1.
[0034]
The sulfur content in the refined oil was measured over time to determine the degradation rate constant. This degradation rate constant is obtained by calculating the reaction rate constant (k) obtained by calculating the desulfurization reaction degradation rate in the 1.3th order and the operation time (t), k = A · exp ( −α · t) is obtained as the value of α. Also, the activation energy of the desulfurization reaction was set to 32 kcal / mol, and the initial operation reaction temperature (° C.) was obtained from the above relational formula. The results are shown in Table 3.
[0035]
[Table 3]

[0036]
As is evident from the results in Table 3, the catalyst of Comparative Example 5 filled with only the catalyst B showing excellent results in the initial desulfurization activity and the denitrification activity which is almost the same as the catalyst of the present invention was also obtained by the formation of coke. However, the catalyst of the present invention suppresses the generation of coke as compared with the case where only the catalyst B is used, and has about twice the catalyst life as compared with the case where only the catalyst B is used. Have.
[0037]
From the above results, hydrorefining is performed using a catalyst containing molybdenum , nickel, and phosphorus as the first hydrorefining catalyst, and using molybdenum , cobalt, and phosphorus as the second hydrotreating catalyst. In addition, the reaction temperature at the beginning of the operation is almost the same as that obtained when only the catalyst B having a high desulfurization activity is used, and the catalyst life is long, and the catalyst is excellent as a hydrocarbon oil hydrorefining catalyst. I understand.
[0038]
【The invention's effect】
The hydrorefining method of the present invention suppresses the production of coke, prolongs the catalyst life, and sufficiently reduces the sulfur content and nitrogen content of the refined oil, and unstable components to provide a product having excellent stability and the like. It has a special effect that a refined oil can be obtained.

Claims

First hydrorefining of a hydrocarbon oil containing 8 to 16 % by weight of molybdenum in terms of metal, 1 to 6% by weight of nickel in terms of metal, and 1 to 6% by weight of phosphorus in terms of element under hydrogen pressure. Contact with a catalyst, and then contact with a second hydrotreating catalyst containing 8 to 16 % by weight of molybdenum in terms of metal, 1 to 6% by weight of cobalt in terms of metal and 1 to 6% by weight of phosphorus in terms of element. A hydrorefining method for a hydrocarbon oil.

2. The method for hydrorefining hydrocarbon oil according to claim 1, wherein the capacity of the first hydrorefining catalyst in the total catalyst capacity is 15 to 85%.

The hydrogenation of hydrocarbon oil according to claim 1 or 2, wherein the hydrocarbon oil is a naphtha fraction, a kerosene fraction, a gas oil fraction or a vacuum gas oil fraction containing a pyrolysis oil or a catalytic cracking oil. Purification method.