JP2004137353A

JP2004137353A - Method for hydrodesulfurization of gas oil and gas oil composition obtained by the method

Info

Publication number: JP2004137353A
Application number: JP2002302543A
Authority: JP
Inventors: Ryuichiro Iwamoto; 岩本　隆一郎; Mamoru Nomura; 野村　守
Original assignee: Idemitsu Kosan Co Ltd
Current assignee: Idemitsu Kosan Co Ltd
Priority date: 2002-10-17
Filing date: 2002-10-17
Publication date: 2004-05-13

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for hydrodesulfurizing gas oil, with which a gas oil fraction is hydrodesulfurized, its sulfur content is efficiently and economically reduced to ≤15 mass ppm and deterioration of hue is controlled. <P>SOLUTION: The method for hydrodesulfurizing gas oil comprises bringing the gas oil fraction having specific properties into contact with a catalyst obtained by supporting cobalt and/or nickel, molybdenum and phosphorus on a refractory inorganic carrier in the presence of hydrogen under reaction conditions of 300-400°C, 0.5-3.0 h<SP>-1</SP>LHSV (liquid hourly space velocity), 3-10 MPa hydrogen partial pressure and the ratio of hydrogen/oil of 150-500 Nm<SP>3</SP>/kL to carry out hydrodesulfurization, controlling ASTM hue to 0.1-2.5 and reducing a sulfur content to ≤15 mass ppm. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、軽油の水素化脱硫方法及びその方法で得られた軽油組成物に関する。さらに詳しくは、本発明は、ディーゼルエンジン用燃料油などとして用いられる軽油留分を水素化脱留処理して、その硫黄分を１５質量ｐｐｍ以下、好ましくは１０質量ｐｐｍ以下に効率よく、経済的に低減させると共に、色相の劣化を抑制する方法、及びこの方法により製造された軽油組成物に関するものである。
【０００２】
【従来の技術】
近年、大気環境の改善のために、燃料油の燃焼に起因する二酸化炭素ガス、パティキュレート・マター（ＰＭ）、ＮＯ_Ｘ、硫黄酸化物などの環境汚染物質の削減が求められており、それに伴い、自動車排ガス規制の強化と燃料の品質規制の強化が図られている。
ところで、ディーゼルエンジン車は、ガソリンエンジン車に比べて、燃費効率がよく、二酸化炭素の削減に有効である上、燃料油として用いられる軽油は、ガソリンに比べてコストが低いというメリットがある。しかしながら、ディーゼル車から排出される燃焼ガス中に含まれるＰＭが、近年、環境汚染の問題で大きくとりあげられている。このＰＭは、すすなどの燃料油の細かな燃えかすであって、人体に入ると呼吸器系に悪影響を与えることが知られている。したがって、排出ガス中のＰＭの削減がディーゼル車の最大の課題となっている。
【０００３】
そのため、わが国においては、２００５年に達成をめざす新規制では、メーカー各社は現行規制の１／３までＰＭ排出量を削減しなければならず、また、東京都においては２００３年を目途に都内を走るディーゼル車にＤＰＦ（ディーゼル微粒子除去装置：ディーゼル・パティキュレート・フィルター）の装着を義務づけることを検討しており、他の自治体にも広がる可能性が大きい。
このような事情から、効率がよく、実用的なＤＰＦの開発が積極的に行われ、現在数種の形式のＤＰＦが提案されている。その一つとして、例えばＮＯ_２酸化方式による連続再生式ＤＰＦがある。この連続再生式ＤＰＦは、フィルターとしてウォールフローハニカム構造の多孔質セラミックを用い、その上流側に設けた酸化触媒により、ＮＯ_ｘをＮＯ_２に酸化し、このＮＯ_２の強い酸化力を利用して、低温でフィルターに捕集されたＰＭを燃焼させる連続再生装置である。しかしながら、この方式では、排ガス中の硫黄分により、該酸化触媒の活性が劣化するため、十分な処理性能を長期間にわたって安定に維持させるには、燃料油（軽油）中の硫黄分を低減させる必要がある。
【０００４】
軽油の水素化脱硫処理については、数多くの技術が開発されている。通常、技術的には脱硫温度を上昇させることで低硫黄化は達成できるが、このような軽油は色相が急激に悪化することが知られている。このため、色相改善の目的で二段水添処理などのプロセスの対応（例えば、特許文献１参照）や貴金属を用いた触媒の使用などが提案されているが、装置が複雑になったり、触媒が高価になるなどの問題があった。
また、軽油留分を水素化脱硫処理して、硫黄分を、例えば１５質量ｐｐｍ以下にするには、触媒の交換頻度を上げたり、反応塔を増設したりすることで達成することができるが、この方法は経済的でない。
このように、硫黄分が１５質量ｐｐｍ以下で、かつ良好な色相を有する軽油組成物を、効率よく、かつ経済的に得ることのできる軽油の水素化脱硫方法は、これまで見出されていないのが実状である。
【０００５】
【特許文献１】
特開平５−７８６７０号公報
【０００６】
【発明が解決しようとする課題】
本発明は、このような状況下で、ディーゼルエンジン用燃料油などとして用いられる軽油留分を水素化脱留処理して、その硫黄分を１５質量ｐｐｍ以下、好ましくは１０質量ｐｐｍ以下に効率よく、経済的に低減させると共に、色相の劣化を抑制する方法、及びその方法で得られた軽油組成物を提供することを目的とするものである。
【０００７】
【課題を解決するための手段】
本発明者らは、前記目的を達成するために鋭意研究を重ねた結果、特定の性状を有する軽油留分を、所定の反応条件下で、特定の触媒と接触させ、水素化脱硫処理することにより、その目的を達成し得ることを見出した。本発明は、かかる知見に基づいて完成したものである。
【０００８】
すなわち、本発明は、
・　硫黄分０．５〜２．５質量％、１５℃密度０．８１〜０．８７ｇ／ｃｍ^３、塩基性窒素分１０〜２００質量ｐｐｍ、全芳香族分２０〜４０体積％、三環以上の芳香族分０．１〜１０体積％、蒸留９０％点が３００〜３８０℃、ＡＳＴＭ色相０．１〜１．０及び全硫黄化合物に占めるＣ_２ジベンゾチオフェンとＣ_３ジベンゾチオフェンの合計割合が４０質量％以下の性状を有する軽油留分を、反応温度３００〜４００℃、ＬＨＳＶ（液時空間速度）０．５〜３．０ｈ^−１、水素分圧３〜１０ＭＰａ、水素／油比１５０〜５００Ｎｍ^３／ｋＬの反応条件下において、水素の共存下、コバルト及び／又はニッケル、モリブデン及びリンを耐火性無機担体に担持してなる触媒と接触させることにより、水素化脱硫処理し、ＡＳＴＭ色相を０．１〜２．５に抑えると共に、硫黄分を１５質量ｐｐｍ以下に低減させることを特徴とする軽油の水素化脱硫方法、
（２）硫黄分を１０質量ｐｐｍ以下に低減させる上記（１）の軽油の水素化脱硫方法、
・　水素消費量３０〜７０Ｎｍ^３／ｋＬの条件で水素化脱硫処理する上記（１）、（２）の軽油の水素化脱硫方法、
【０００９】
・　硫黄分の低減した軽油留分の一部をリサイクルして、水素化脱硫処理する上記（１）〜（３）の軽油の水素化脱硫方法、
・　相対的に水素消費量の少ない触媒から水素消費量の多い触媒の順に、少なくとも二種の触媒を組み合わせて水素化脱硫処理する上記（１）〜（４）の軽油の水素化脱硫方法、
・　二種以上の触媒を組み合わせる場合に、第二触媒層以降にニッケル、モリブデン及びリンと共に、チタンを含む触媒を使用して水素化脱硫処理する上記（５）の軽油の水素化脱硫方法、
・　水素化脱硫処理に用いる軽油留分が直留軽油留分に、硫黄分０．０１〜０．１質量％、１５℃密度０．８３〜０．８８ｇ／ｃｍ^３、全芳香族分３５〜４５体積％、三環以上の芳香分３〜４体積％及び蒸留９０％点が３２０〜３６０℃の性状を有する炭化水素留分を、合計量に基づき４０体積％以下の割合で添加したものである上記（１）〜（６）の軽油の水素化脱硫方法、
・　炭化水素留分が、減圧軽油の水素化脱硫装置から得られる低硫黄軽油留分である上記（７）の軽油の水素化脱硫方法、
・　水素化脱硫処理に用いる軽油留分が、直留軽油留分に、硫黄分０．０１〜　０．１質量％、窒素分１００〜２００質量ｐｐｍ、１５℃密度０．８３〜０．９０ｇ／ｃｍ^３及び蒸留９０％点が３２０〜３８０℃の性状を有する炭化水素留分を、合計量に基づき４０体積％以下の割合で添加したものである上記（１）〜（６）の軽油の水素化脱硫方法、
【００１０】
（１０）炭化水素留分が、常圧残油の水素化脱硫装置から得られる低硫黄軽油留分である上記（９）の軽油の水素化脱硫方法、
（１１）水素化脱硫処理に用いる軽油留分が、直留軽油留分に、硫黄分０．１〜０．８質量％、窒素分６００〜８００質量ｐｐｍ、１５℃密度０．８８〜０．９８ｇ／ｃｍ^３、蒸留９０％点が３２０〜３８０℃及び全芳香族分５０〜１００体積％の性状を有する炭化水素留分を、合計量に基づき３０体積％以下の割合で添加したものである上記（１）〜（６）の軽油の水素化脱硫方法、
（１２）炭化水素留分が、接触分解装置から得られる軽油留分である上記（１１）の軽油の水素化脱硫方法、
（１３）水素化脱硫処理に用いる軽油留分が、直留軽油留分に、硫黄分０．０１〜０．１質量％、窒素分１００〜５００質量ｐｐｍ、１５℃密度０．７５〜０．８７ｇ／ｃｍ^３、蒸留９０％点が１８０〜２６０℃及び全芳香族分３０〜９０体積％の性状を有する炭化水素留分を、合計量に基づき４０体積％以下の割合で添加したものである上記（１）〜（６）の軽油の水素化脱硫方法、
（１４）炭化水素留分が、接触分解装置から得られる灯油留分である上記（１３）の軽油の水素化脱硫方法、
（１５）水素化脱硫処理に用いる軽油留分が、直留軽油留分に、硫黄分０〜５０質量ｐｐｍ、１５℃密度０．８０〜０．８５ｇ／ｃｍ^３、蒸留９０％点が３２０〜３６０℃及び全芳香族分５〜２５体積％の性状を有する炭化水素留分を、合計量に基づき４０体積％以下の割合で添加したものである上記（１）〜（６）の軽油の水素化脱硫方法、
（１６）炭化水素留分が、重質軽油の水素化分解装置から得られる軽油留分である上記（１５）の軽油の水素化脱硫方法、及び
（１７）上記（１）〜（１６）の水素化脱硫方法により製造されたことを特徴とする軽油組成物、
を提供するものである。
【００１１】
【発明の実施の形態】
本発明の軽油の水素化脱硫方法においては、水素化脱硫触媒として、耐火性無機担体にコバルト及び／又はニッケル、モリブデン及びリンを担持したものが用いられる。
当該触媒における耐火性無機担体としては、特に制限はなく、通常軽油の水素化脱硫触媒に使用される耐火性無機担体の中から、適宜選択して用いることができる。この耐火性無機担体の例としては、アルミナ、シリカ、マグネシア、チタニア、ジルコニア、アルミナ−シリカ、アルミナ−ボリア、アルミナ−チタニア、チタニア−シリカ、アルミナ−マグネシア、シリカ−マグネシア、アルミナ−ジルコニアなどが挙げられる。これらは一種を単独で用いてもよく、二種以上を組み合わせて用いてもよい。これらの耐火性無機担体はゲル状物質、固体微粉末に水を加えたもの、ゾル状物質、共沈法（コゲル法）により得られたものなどが好適である。
上記担体の製造において、乾燥条件は、乾燥温度３０〜２００℃、乾燥時間０．１〜２４時間が適しており、また焼成条件は、焼成温度３００〜７５０℃、好ましくは４５０〜７００℃が適している。焼成温度が３００℃より低いと焼成効果（不純物の除去）が十分でなく、７５０℃を超えると無機酸化物等の変質が起こり易くなる。焼成時間は１〜１０時間、好ましくは２〜７時間が適している。当該触媒においては、このようにして得られた耐火性無機担体に、コバルト及び／又はニッケルと、モリブデンと、リンとが担持される。触媒中における担持元素の含有量は、酸化物基準で、コバルト及び／又はニッケルが、通常１〜１５質量％、好ましくは３〜１０質量％の範囲で選定され、モリブデンが、通常１０〜５０質量％、好ましくは１５〜４０質量％の範囲で選定される。一方、リンは、酸化物基準で、通常０．５〜１０質量％、好ましくは１〜７質量％の範囲で選定される。活性金属は、例えばＮｉＭｏＰやＣｏＭｏＰが母体として挙げられるが、ＭｏにＦｅ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕ、Ｉｒ、Ｏｓなどの周期表第８、９、１０族金属の中から選ばれる少なくとも一種を添加してもよい。
【００１２】
担体への金属担持法としては、常圧含浸法、真空含浸法、混練法、共沈法など通常の方法を用いることができる。この際、金属の分散性を高めるため、金属溶液に水溶性有機溶媒を添加してもよい。担持されたものは乾燥、焼成工程を経て本発明における触媒となる。乾燥、焼成条件は通常の水素化脱硫触媒の乾燥、焼成条件を適用することができる。具体的には、乾燥温度３０〜２００℃、乾燥時間０．１〜２４時間、焼成温度２００〜７５０℃、好ましくは２５０〜７００℃、焼成時間１〜１０時間、好ましくは２〜７時間が好適である。焼成温度が２００℃より低いと焼成効果（不純物の除去）が不十分となり、７５０℃を超えると耐火性無機担体の変質、担持金属のシンタリングによる変質などが起こり易く好ましくない。
このようにして調製された触媒の比表面積は、通常７０〜３００ｍ^２／ｇ、好ましくは１００〜２６０ｍ^２／ｇの範囲である。
次に、前記触媒の調製方法の好ましい態様について説明する。
担持処理に用いられる金属化合物としては、特に限定されないが酸化物、硫酸塩、硝酸塩、炭酸塩、塩基性炭酸塩、シュウ酸塩、酢酸塩、アンモニウム塩、有機酸塩、ハロゲン化物等の水溶液が好適に用いられる。具体的には、パラモリブデン酸塩、メタモリブデン酸塩、三酸化モリブデン、硝酸ニッケル、硝酸コバルト、塩基性炭酸コバルト、塩基性炭酸ニッケル等を水溶液としたものが挙げられる。
【００１３】
また、金属化合物の担持処理に水酸基及び／又はエーテル結合を有する水溶性有機化合物を用いると触媒上での担持金属の分散がよくなり、脱硫活性等が向上させ得る。担持処理に用いられる水酸基及び／又はエーテル結合を有する水溶性有機化合物としては、ポリオキシエチレンオクチルフェニルエーテル、ポリオキシエチレンフェニルエーテル、ポリエチレングリコール等のエーテル含有水溶性高分子、ポリビニルアルコール等のアルコール性水酸基含有水溶性高分子、サッカロース、グルコース等の各糖類、メチルセルロース、デンプン等の水溶性多糖類若しくはこれらの誘導体が挙げられる。好ましくはポリエチレングリコールが用いられる。
前記水溶性有機化合物としては分子量が通常３００以上のものが用いられる。好ましくは分子量が３００〜１０，０００、更に好ましくは分子量３５０〜６，０００のものが用いられる。３００未満では触媒活性に劣り、１０，０００を超えると溶解や担持工程に時間を要し、取扱いが困難となることがある。前記水溶性有機化合物の添加量は、耐火性無機担体１００質量部に対して好ましくは、０．５〜１００質量部、更に好ましくは１〜５０質量部である。０．５質量部未満では、添加効果が発揮されないことがあり、１００質量部を超えると担持が困難になることがある。
担持法は特に限定はないが、例えば真空含浸法、常圧含浸法、浸漬法、混練法、塗布法等の公知の担持操作及びこれらを組み合わせた方法が用いられる。前記金属化合物と前記水溶性有機化合物の耐火性無機担体への担持は、金属化合物と水溶性有機化合物の水溶液を用いて同時に行うことが好ましい。あらかじめ水溶性有機化合物又はその水溶液を用いて水溶性有機化合物を耐火性無機担体上に担持し、次いで金属化合物水溶液を用いて金属化合物を耐火性無機担体上に担持してもよい。
【００１４】
本発明の軽油の水素化脱硫方法においては、原料の軽油留分として、硫黄分０．５〜２．５質量％、好ましくは０．８〜１．５質量％、１５℃密度０．８１〜０．８７ｇ／ｃｍ^３、塩基性窒素分１０〜２００質量ｐｐｍ、好ましくは１０〜１００質量ｐｐｍ、全芳香族分２０〜４０体積％、好ましくは２０〜３５体積％、三環以上の芳香族分０．１〜１０体積％、好ましくは０．３〜５体積％、蒸留９０％点が３００〜３８０℃、ＡＳＴＭ色相０．１〜１．０及び全硫黄化合物に占めるＣ_２ジベンゾチオフェンとＣ_３ジベンゾチオフェンの合計割合が４０質量％以下の性状を有する軽油留分が用いられる。
このように、原料の軽油留分について、難脱硫化合物であるＣ_２ジベンゾチオフェンとＣ_３ジベンゾチオフェンの合計量の全硫黄化合物に占める割合、全芳香族分、三環以上の芳香族分、塩基性窒素分などを規定することにより、脱硫反応性が向上する。
前記Ｃ_２ジベンゾチオフェン及びＣ_３ジベンゾチオフェンとは、ジベンゾチオフェン環に結合された置換基である炭化水素基の全炭素数が、それぞれ２及び３の化合物を指す。また、塩基性窒素分とは、カルバゾール、キノリン等を指す。なお、前記原料である軽油留分の性状の測定方法については後述する。
前記の性状を有する原料の軽油留分としては、常圧蒸留から得られる軽油留分である直留軽油を単独で用いてもよいし、この直留軽油に、水素化脱硫処理して硫黄分を低減させた軽油留分の一部をリサイクルしてブレンドしたものを用いてもよく、あるいは、該直留軽油に以下に示す（１）〜（５）の炭化水素留分を、合計量に基づき４０体積％以下の割合でブレンドしたものを用いてもよい。
【００１５】
（１）硫黄分０．０１〜０．１質量％、１５℃密度０．８３〜０．８８ｇ／ｃｍ^３、全芳香族分３５〜４５体積％、三環以上の芳香分３〜４体積％及び蒸留９０％点が３２０〜３６０℃の性状を有する炭化水素留分、例えば減圧軽油の水素化脱硫装置から得られる低硫黄軽油留分。
（２）硫黄分０．０１〜０．１質量％、窒素分１００〜２００質量ｐｐｍ、１５℃密度０．８３〜０．９０ｇ／ｃｍ^３及び蒸留９０％点が３２０〜３８０℃の性状を有する炭化水素留分、例えば常圧残油の水素化脱硫装置から得られる低硫黄軽油留分。
（３）硫黄分０．１〜０．８質量％、窒素分６００〜８００質量ｐｐｍ、１５℃密度０．８８〜０．９８ｇ／ｃｍ^３、蒸留９０％点が３２０〜３８０℃及び全芳香族分５０〜１００体積％の性状を有する炭化水素留分、例えば接触分解装置から得られる軽油留分。
（４）硫黄分０．０１〜０．１質量％、窒素分１００〜５００質量ｐｐｍ、１５℃密度０．７５〜０．８７ｇ／ｃｍ^３、蒸留９０％点が１８０〜２６０℃及び全芳香族分３０〜９０体積％の性状を有する炭化水素留分、例えば接触分解装置から得られる灯油留分。
（５）硫黄分０〜５０質量ｐｐｍ、１５℃密度０．８０〜０．８５ｇ／ｃｍ^３、蒸留９０％点が３２０〜３６０℃及び全芳香族分５〜２５体積％の性状を有する炭化水素留分、例えば重質軽油の水素化分解装置から得られる軽油留分。
このように、直留軽油に、異なる性状の各種の炭化水素油を、合計量に基づき、好ましくは４０体積％以下の割合でブレンドして、反応性を調整することにより、硫黄分１５質量ｐｐｍ以下、好ましくは１０質量ｐｐｍ以下の脱硫軽油を効率よく得ることができる。
【００１６】
なお、前記（１）〜（４）の炭化水素油は、直留軽油に対し、合計量に基づき、３０体積％以下の割合でブレンドすることが、より好ましい。
次に、前記の性状を有する原料の軽油留分を、前述の本発明に係る触媒と接触させて、水素化脱硫処理する方法について説明する。
反応形式については特に制限はなく、固定床、移動床、沸騰床、懸濁床などの各種形式の中から適宜選択することができるが、通常は固定床流通式反応装置を用いて、水素化脱硫処理が行われる。また、原料の軽油留分の流通方式としては、ダウンフロー、アップフローの両方式を使用することができる。
反応帯域の数［充填触媒層数（段数で呼ぶこともある。）］は、一つであってもよく、二つ以上の複数であってもよい。反応帯域の数が二つ以上の複数である場合には、相対的に水素消費量の少ない触媒から水素消費量の多い触媒の順に二種以上の触媒を組み合わせて水素化脱硫処理することにより、難脱硫性硫黄化合物を効果的に脱硫することができ、硫黄分を所望の値以下に低減した脱硫軽油を得ることができるので、好ましい。
【００１７】
一般に、Ｃｏ−Ｍｏ系触媒は、Ｎｉ−Ｍｏ系触媒よりも水素消費量は少ない。そして、Ｔｉが含まれると水素消費量が多くなり、また金属担持量が多くなると水素消費量が多くなる。
したがって、二種以上の触媒を組み合わせる場合には、第二触媒層（第二反応帯域）以降に、ニッケル、モリブデン及びリンと共に、チタンを含む触媒を使用するのが有利である。また、第一触媒層における触媒量と、第二触媒層以降における触媒量の割合としては特に制限はないが、通常容量比で１０：９０〜８０：２０、好ましくは１５：８５〜６０：４０の範囲で選ばれる。
このように、二種以上の触媒を組み合わせ、多段反応帯域にて水素化脱硫処理を行うことにより、第一の反応帯域で脱硫活性の高い触媒により、易脱硫性の硫黄化合物は容易に脱硫される。そして、第二の反応帯域以降において、水素化活性の高い（水素消費量が多い）触媒により、難脱硫性の硫黄化合物であるＣ_２ジベンゾチオフェンやＣ_３ジベンゾチオフェンの芳香環を核水素化することにより、Ｃ−Ｓ結合の切断が促進され、前記難脱硫性の硫黄化合物が効果的に脱硫される。
【００１８】
本発明の水素化脱硫処理における反応条件は、反応温度が３００〜４００℃、ＬＨＳＶ（液時空間速度）が０．５〜３．０ｈ^−１、好ましくは０．５〜２．０ｈ^−１、さらに好ましくは０．５〜１．５ｈ^−１、水素分圧が３〜１０ＭＰａ、好ましくは４〜８ＭＰａ、水素／油比が１５０〜５００Ｎｍ^３／ｋＬ、好ましくは２００〜４００Ｎｍ^３／ｋＬである。また、水素消費量は、コーク劣化を抑制するために、３０〜７０Ｎｍ^３／ｋＬの範囲に制御することが好ましい。
このようにして、原料の軽油留分を水素化脱硫処理することにより、ＡＳＴＭ色相が０．１〜２．５であって、硫黄分が１５質量ｐｐｍ以下、好ましくは１０質量ｐｐｍ以下に低減された軽油が得られる。なお脱硫軽油の硫黄分測定方法については後述する。
本発明はまた、前述の軽油の水素化脱硫方法により製造された軽油組成物をも提供する。
本発明の軽油組成物は硫黄分が１５質量ｐｐｍ以下、好ましくは１０質量ｐｐｍ以下に低減されており、大気汚染に与える影響が少なく、特にディーゼル車のＤＰＦにおける酸化触媒の長寿命化を図ることができ、ＰＭ低減に効果を奏する。
【００１９】
【実施例】
次に、本発明を実施例により、さらに詳細に説明するが、本発明は、これらの例によってなんら限定されるものではない。
なお、各物性は、以下に示す方法に従って測定した。
＜触媒＞
（１）比表面積
ＢＪＨ法（Ｂａｒｒｅｔ−Ｊｏｙｎｅｒ−Ｈａｌｅｎｄａ）法により測定した。
＜原料の軽油留分＞
（１）硫黄分
ＪＩＳ　Ｋ２５４１に準拠して測定した。
（２）密度
ＪＩＳ　Ｋ２２４９に準拠して測定した。
（３）窒素分、塩基性窒素分
窒素分はＪＩＳ　Ｋ２６０９、塩基性窒素分はＡｎａｌ．Ｃｈｅｍ．，３７，５４（１９６５）に準拠して測定した。
（４）全芳香族分、三環以上の芳香族分
ＪＰＩ−５Ｓ−４９（石油学会法）に準拠して測定した。
（５）蒸留９０％点
ＪＩＳ　Ｋ２２５４に準拠して測定した。
（６）ＡＳＴＭ色相
ＪＩＳ　Ｋ２５８０に準拠して測定した。
（７）全硫黄化合物に占めるＣ_２ジベンゾチオフェン（Ｃ_２ＤＢＴ）とＣ_３ジベンゾチオフェン（Ｃ_３ＤＢＴ）の合計割合
ＧＣ−ＡＥＤ（ガスクロ−原子発光検出器）を使用して測定した。
＜脱硫軽油＞
（１）硫黄分
前記原料の軽油留分における（１）と同様にして測定した。
（２）ＡＳＴＭ色相
前記原料の軽油留分における（６）と同様にして測定した。
（３）窒素分
前記原料の軽油留分における（３）と同様にして測定した。
また、各例で使用する原料油の性状を第１表に、触媒の性状を第２表に示す。
【００２０】
【表１】

【００２１】
【表２】

【００２２】
［注］
原料油Ａ・・直留軽油（常圧蒸留から得られる軽油留分）
原料油Ｂ・・間脱軽質軽油（減圧留出油の水素化処理時（脱硫，マイルド分解）に得られる軽油留分）
原料油Ｃ・・直脱軽質軽油（常圧残油の水素化脱硫処理時に得られる軽油留分）
原料油Ｄ・・ライトサイクル油（ＲＦＣＣ，ＦＣＣのライトサイクルオイル）
原料油Ｅ・・流動接触分解の灯油留分（ＲＦＣＣ，ＦＣＣの軽質ライトサイクルオイル）
原料油Ｆ・・水素化分解軽油（減圧留出油の水素化分解時に得られる軽油留分）
原料油Ｇ・・直留軽油（常圧蒸留から得られる軽油留分，原料油Ａより重質）
【００２３】
【表３】

【００２４】
［注］
相対水素消費量は実施例１と同一の原料油，反応条件で各触媒毎に求め、触媒Ａを１００とした場合の値を示した。
実施例１
第１表に示す性状の原料油Ａを、第２表に示す触媒Ａを用いて、第３表に示す反応条件で水素化脱硫処理を行った。得られた脱硫軽油の硫黄分とＡＳＴＭ色相と窒素分を第３表に示す。
【００２５】
実施例２
実施例１で得られた脱硫軽油Ａをリサイクルし、原料油Ａに、合計量に基づき３０ｖｏｌ％の割合でブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
実施例３
第一触媒層に触媒Ｂを２５ｖｏｌ％、第二触媒層に触媒Ａを７５ｖｏｌ％充填した以外は、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
実施例４
第一触媒層に触媒Ｂを２０ｖｏｌ％、第二触媒層に触媒Ｃを２０ｖｏｌ％、第三触媒層に触媒Ａを６０ｖｏｌ％充填した以外は、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
実施例５
第１表に示す性状の原料油Ａに、原料油Ｂを合計量に基づき２０ｖｏｌ％ブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
【００２６】
実施例６
第１表に示す性状の原料油Ａに、原料油Ｃを合計量に基づき１０ｖｏｌ％ブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
実施例７
第１表に示す性状の原料油Ａに、原料油Ｄを合計量に基づき５ｖｏｌ％ブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
実施例８
第１表に示す性状の原料油Ａに、原料油Ｅを合計量に基づき１５ｖｏｌ％ブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
実施例９
第１表に示す性状の原料油Ａに、原料油Ｆを合計量に基づき２０ｖｏｌ％ブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
【００２７】
比較例１
実施例１において、原料油Ａの代わりに第１表に示す性状の原料油Ｇを用いた以外は、実施例１と同様にして水素化脱硫処理を行った。得られた脱硫軽油の性状を第３表に示す。
比較例２
実施例１において、反応条件を第３表に示す条件とした以外は、実施例１と同様にして水素化脱硫処理を行った。得られた脱硫軽油の性状を第３表に示す。
比較例３
第１表に示す性状の原料油Ａに、原料油Ｄを合計量に基づき７０ｖｏｌ％ブレンドしたものを、実施例１と同様にして水素化脱硫処理した。得られた脱硫軽油の性状を第３表に示す。
【００２８】
【表４】

【００２９】
【表５】

【００３０】
【表６】

【００３１】
実施例１と、実施例３及び実施例４を比較して分かるように、相対的に水素消費量の少ない触媒から水素消費量の多い触媒の順に触媒を組み合わせ、反応帯域を２段以上にすることにより、得られる脱硫軽油の硫黄分は、さらに低減する。
【００３２】
【発明の効果】
本発明によれば、ディーゼルエンジン用燃料油などとして用いられる軽油留分を水素化脱硫処理して、その硫黄分を１５質量ｐｐｍ以下、好ましくは１０質量ｐｐｍ以下に効率よく、経済的に低減させると共に、色相の劣化を抑制することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas oil hydrodesulfurization method and a gas oil composition obtained by the method. More specifically, the present invention is an economical and economical method in which a gas oil fraction used as a fuel oil for a diesel engine or the like is subjected to hydrodestillation treatment to reduce its sulfur content to 15 mass ppm or less, preferably 10 mass ppm or less. And a gas oil composition produced by this method.
[0002]
[Prior art]
In recent years, in order to improve the atmospheric environment, carbon dioxide gas, particulate matter (PM), NO _X There is a demand for reduction of environmental pollutants such as sulfur oxides, and accordingly, regulations on automobile exhaust gas and regulations on fuel quality have been strengthened.
By the way, a diesel engine vehicle has better fuel efficiency than a gasoline engine vehicle, is effective in reducing carbon dioxide, and has a merit that light oil used as a fuel oil has a lower cost than gasoline. However, PM contained in the combustion gas discharged from diesel vehicles has recently been widely considered due to the problem of environmental pollution. This PM is a fine burnt of fuel oil such as soot, and is known to have an adverse effect on the respiratory system when it enters the human body. Therefore, reduction of PM in exhaust gas is the biggest issue for diesel vehicles.
[0003]
Therefore, in Japan, new regulations aimed at achieving in 2005 require manufacturers to reduce PM emissions to one-third of the current regulations. We are considering making mandatory the installation of DPF (Diesel Particulate Filter) on running diesel vehicles, and there is a great possibility that it will spread to other local governments.
Under these circumstances, efficient and practical DPFs are being actively developed, and several types of DPFs are currently being proposed. As one of them, for example, NO ₂ There is a continuous regeneration type DPF using an oxidation method. This continuous regeneration type DPF uses a porous ceramic having a wall flow honeycomb structure as a filter, and uses an oxidation catalyst provided on the upstream side thereof to produce NO. _x NO ₂ Oxidized to this NO ₂ It is a continuous regeneration device that burns PM trapped in the filter at a low temperature by utilizing the strong oxidizing power of the filter. However, in this method, since the activity of the oxidation catalyst is deteriorated by the sulfur content in the exhaust gas, the sulfur content in the fuel oil (light oil) is reduced in order to stably maintain sufficient treatment performance for a long period of time. There is a need.
[0004]
Many technologies have been developed for hydrodesulfurization of gas oil. Usually, technically, sulfur reduction can be achieved by increasing the desulfurization temperature, but it is known that the hue of such a light oil rapidly deteriorates. For this reason, for the purpose of improving the hue, it has been proposed to cope with a process such as a two-stage hydrogenation treatment (for example, see Patent Document 1) or use a catalyst using a noble metal, but the apparatus becomes complicated or the catalyst becomes expensive. And so on.
Further, in order to reduce the sulfur content to, for example, 15 ppm by mass or less by hydrodesulfurizing the gas oil fraction, it can be achieved by increasing the catalyst replacement frequency or increasing the number of reaction towers. , This method is not economical.
As described above, a gas oil hydrodesulfurization method capable of efficiently and economically obtaining a gas oil composition having a sulfur content of 15 mass ppm or less and having a good hue has not been found. This is the actual situation.
[0005]
[Patent Document 1]
JP-A-5-78670
[0006]
[Problems to be solved by the invention]
Under such circumstances, the present invention efficiently hydrotreats a light oil fraction used as a fuel oil for a diesel engine or the like to reduce its sulfur content to 15 mass ppm or less, preferably 10 mass ppm or less. It is an object of the present invention to provide a method for economically reducing the hue while suppressing the deterioration of the hue, and a light oil composition obtained by the method.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, under a predetermined reaction condition, a gas oil fraction having a specific property is brought into contact with a specific catalyst and subjected to hydrodesulfurization treatment. Has found that the object can be achieved. The present invention has been completed based on such findings.
[0008]
That is, the present invention
-Sulfur content 0.5-2.5 mass%, 15 degreeC density 0.81-0.87 g / cm ³ The basic nitrogen content is 10 to 200 mass ppm, the total aromatic content is 20 to 40% by volume, the tricyclic or higher aromatic content is 0.1 to 10% by volume, the distillation 90% point is 300 to 380 ° C, the ASTM hue is 0. 1 to 1.0 and C in total sulfur compounds ₂ Dibenzothiophene and C ₃ A gas oil fraction having a property that the total ratio of dibenzothiophene is 40% by mass or less is subjected to a reaction temperature of 300 to 400 ° C. and an LHSV (liquid hourly space velocity) of 0.5 to 3.0 h. ^-1 , Hydrogen partial pressure 3-10 MPa, hydrogen / oil ratio 150-500 Nm ³ Under the reaction conditions of / kL, in the presence of hydrogen, cobalt and / or nickel, molybdenum and phosphorus are brought into contact with a catalyst supported on a refractory inorganic carrier to carry out a hydrodesulfurization treatment, and to obtain an ASTM hue of 0.1%. A method for hydrodesulfurizing gas oil, comprising reducing the sulfur content to 15 mass ppm or less while suppressing the sulfur content to 1 to 2.5,
(2) the method for hydrodesulfurizing gas oil according to the above (1), wherein the sulfur content is reduced to 10 mass ppm or less;
・ Hydrogen consumption 30-70Nm ³ (1) The method for hydrodesulfurization of light oil according to (1) or (2), wherein
[0009]
(1) The gas oil hydrodesulfurization method according to the above (1) to (3), wherein a part of the gas oil fraction with reduced sulfur content is recycled and subjected to hydrodesulfurization treatment.
The gas oil hydrodesulfurization method according to any one of the above (1) to (4), wherein at least two kinds of catalysts are combined and subjected to hydrodesulfurization treatment in the order of relatively low hydrogen consumption to high hydrogen consumption.
-When two or more catalysts are combined, the hydrodesulfurization method for gas oil according to (5) above, wherein the second catalyst layer and the subsequent layers are subjected to hydrodesulfurization treatment using a catalyst containing titanium together with nickel, molybdenum and phosphorus.
The gas oil fraction used in the hydrodesulfurization treatment is a straight-run gas oil fraction with a sulfur content of 0.01 to 0.1% by mass and a density at 15 ° C of 0.83 to 0.88 g / cm. ³ 35% to 45% by volume of total aromatics, 3% to 4% by volume of aromatics having three or more rings and a hydrocarbon fraction having properties of a distillation 90% point of 320 to 360 ° C., up to 40% by volume based on the total amount (1) to (6) the method for hydrodesulfurization of light oil,
The method for hydrodesulfurizing gas oil according to (7), wherein the hydrocarbon fraction is a low sulfur gas oil fraction obtained from a vacuum gas oil hydrodesulfurization apparatus;
The gas oil fraction used in the hydrodesulfurization treatment is such that the straight-run gas oil fraction has a sulfur content of 0.01 to 0.1% by mass, a nitrogen content of 100 to 200 mass ppm, and a 15 ° C density of 0.83 to 0.90 g / cm ³ And hydrodesulfurization of gas oil according to the above (1) to (6), wherein a hydrocarbon fraction having a property of having a distillation 90% point of 320 to 380 ° C. is added in a proportion of 40% by volume or less based on the total amount. Method,
[0010]
(10) The gas oil hydrodesulfurization method according to the above (9), wherein the hydrocarbon fraction is a low sulfur gas oil fraction obtained from a normal pressure residual oil hydrodesulfurization apparatus;
(11) The gas oil fraction used in the hydrodesulfurization treatment is such that the straight gas oil fraction has a sulfur content of 0.1 to 0.8% by mass, a nitrogen content of 600 to 800 mass ppm, and a density at 15 ° C of 0.88 to 0.8%. 98g / cm ³ (1) wherein a hydrocarbon fraction having a distillation 90% point of 320 to 380 ° C. and a total aromatic content of 50 to 100% by volume is added at a ratio of 30% by volume or less based on the total amount. To (6) a method for hydrodesulfurization of gas oil,
(12) The method for hydrodesulfurizing gas oil according to (11) above, wherein the hydrocarbon fraction is a gas oil fraction obtained from a catalytic cracking device;
(13) The gas oil fraction used in the hydrodesulfurization treatment is such that the straight-run gas oil fraction has a sulfur content of 0.01 to 0.1% by mass, a nitrogen content of 100 to 500 ppm by mass, and a 15 ° C density of 0.75 to 0. 87g / cm ³ (1) wherein a hydrocarbon fraction having a distillation 90% point of 180 to 260 ° C. and a total aromatic content of 30 to 90% by volume is added at a ratio of 40% by volume or less based on the total amount. To (6) a method for hydrodesulfurization of gas oil,
(14) The method for hydrodesulfurizing gas oil according to (13) above, wherein the hydrocarbon fraction is a kerosene fraction obtained from a catalytic cracking unit;
(15) The gas oil fraction used in the hydrodesulfurization treatment is such that the straight gas oil fraction has a sulfur content of 0 to 50 mass ppm and a density of 15 ° C of 0.80 to 0.85 g / cm. ³ (1) wherein a hydrocarbon fraction having a distillation 90% point of 320 to 360 ° C. and a total aromatic content of 5 to 25% by volume is added at a ratio of 40% by volume or less based on the total amount. To (6) a method for hydrodesulfurization of gas oil,
(16) The gas oil hydrodesulfurization method according to the above (15), wherein the hydrocarbon fraction is a gas oil fraction obtained from a heavy gas oil hydrocracking apparatus, and
(17) A gas oil composition produced by the hydrodesulfurization method of (1) to (16),
Is provided.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
In the gas oil hydrodesulfurization method of the present invention, a refractory inorganic carrier having cobalt and / or nickel, molybdenum and phosphorus supported thereon is used as the hydrodesulfurization catalyst.
The refractory inorganic carrier in the catalyst is not particularly limited, and can be appropriately selected from the refractory inorganic carriers usually used for gas oil hydrodesulfurization catalysts. Examples of the refractory inorganic carrier include alumina, silica, magnesia, titania, zirconia, alumina-silica, alumina-boria, alumina-titania, titania-silica, alumina-magnesia, silica-magnesia, alumina-zirconia and the like. Can be These may be used alone or in a combination of two or more. These refractory inorganic carriers are preferably a gel-like substance, a substance obtained by adding water to a fine solid powder, a sol-like substance, a substance obtained by a coprecipitation method (a cogel method), and the like.
In the production of the carrier, the drying conditions are suitably a drying temperature of 30 to 200 ° C. and a drying time of 0.1 to 24 hours, and the firing conditions are a firing temperature of 300 to 750 ° C., preferably 450 to 700 ° C. ing. If the firing temperature is lower than 300 ° C., the firing effect (removal of impurities) is not sufficient, and if the firing temperature is higher than 750 ° C., alteration of inorganic oxides and the like is likely to occur. The firing time is 1 to 10 hours, preferably 2 to 7 hours. In the catalyst, cobalt and / or nickel, molybdenum, and phosphorus are supported on the refractory inorganic support thus obtained. As for the content of the supporting element in the catalyst, cobalt and / or nickel are usually selected in the range of 1 to 15% by mass, preferably 3 to 10% by mass, and molybdenum is usually in the range of 10 to 50% by mass on an oxide basis. %, Preferably in the range of 15 to 40% by mass. On the other hand, phosphorus is selected in the range of usually 0.5 to 10% by mass, preferably 1 to 7% by mass on the oxide basis. The active metal may be, for example, NiMoP or CoMoP as a base, and Mo may include at least one metal selected from Group 8, 9, and 10 metals of the periodic table such as Fe, Pt, Pd, Rh, Ru, Ir, and Os. It may be added.
[0012]
As a method for supporting the metal on the carrier, a normal method such as a normal pressure impregnation method, a vacuum impregnation method, a kneading method, and a coprecipitation method can be used. At this time, a water-soluble organic solvent may be added to the metal solution in order to enhance the dispersibility of the metal. The supported catalyst becomes a catalyst in the present invention through a drying and firing process. The drying and calcination conditions may be the same as those for ordinary hydrodesulfurization catalysts. Specifically, a drying temperature of 30 to 200 ° C, a drying time of 0.1 to 24 hours, a firing temperature of 200 to 750 ° C, preferably 250 to 700 ° C, a firing time of 1 to 10 hours, preferably 2 to 7 hours is suitable. It is. If the sintering temperature is lower than 200 ° C., the sintering effect (removal of impurities) becomes insufficient, and if it exceeds 750 ° C., alteration of the refractory inorganic carrier and alteration due to sintering of the supported metal tend to occur, which is not preferable.
The specific surface area of the catalyst thus prepared is usually 70 to 300 m ² / G, preferably 100-260 m ² / G.
Next, a preferred embodiment of the method for preparing the catalyst will be described.
The metal compound used for the supporting treatment is not particularly limited, but may be an aqueous solution of an oxide, a sulfate, a nitrate, a carbonate, a basic carbonate, an oxalate, an acetate, an ammonium salt, an organic acid salt, a halide, or the like. It is preferably used. Specific examples include aqueous solutions of paramolybdate, metamolybdate, molybdenum trioxide, nickel nitrate, cobalt nitrate, basic cobalt carbonate, basic nickel carbonate, and the like.
[0013]
Further, when a water-soluble organic compound having a hydroxyl group and / or an ether bond is used for the supporting treatment of the metal compound, the dispersion of the supporting metal on the catalyst is improved, and the desulfurization activity and the like can be improved. Examples of the water-soluble organic compound having a hydroxyl group and / or an ether bond used in the supporting treatment include water-soluble polymers containing ether such as polyoxyethylene octyl phenyl ether, polyoxyethylene phenyl ether and polyethylene glycol, and alcoholic compounds such as polyvinyl alcohol. Examples include hydroxyl-containing water-soluble polymers, saccharides such as saccharose and glucose, water-soluble polysaccharides such as methylcellulose and starch, and derivatives thereof. Preferably, polyethylene glycol is used.
As the water-soluble organic compound, those having a molecular weight of usually 300 or more are used. Preferably, those having a molecular weight of 300 to 10,000, more preferably 350 to 6,000 are used. If it is less than 300, the catalytic activity is inferior. If it exceeds 10,000, the dissolving and supporting steps require time, and handling may be difficult. The amount of the water-soluble organic compound to be added is preferably 0.5 to 100 parts by mass, more preferably 1 to 50 parts by mass, based on 100 parts by mass of the refractory inorganic carrier. If the amount is less than 0.5 part by mass, the effect of addition may not be exhibited, and if it exceeds 100 parts by mass, loading may be difficult.
The supporting method is not particularly limited, and for example, a known supporting operation such as a vacuum impregnation method, a normal pressure impregnation method, an immersion method, a kneading method, a coating method, and a combination thereof are used. The loading of the metal compound and the water-soluble organic compound on the refractory inorganic carrier is preferably performed simultaneously using an aqueous solution of the metal compound and the water-soluble organic compound. The water-soluble organic compound or the aqueous solution thereof may be used to support the water-soluble organic compound on the refractory inorganic carrier in advance, and then the metal compound may be supported on the refractory inorganic carrier using the aqueous metal compound solution.
[0014]
In the gas oil hydrodesulfurization method of the present invention, the sulfur content of the gas oil fraction of the feedstock is 0.5 to 2.5% by mass, preferably 0.8 to 1.5% by mass, and the density at 15 ° C is 0.81 to 0.81%. 0.87 g / cm ³ 10 to 200 mass ppm, preferably 10 to 100 mass ppm, basic nitrogen content, 20 to 40 volume%, preferably 20 to 35 volume%, total aromatic content, and 0.1 to 10 volume of tricyclic or higher aromatic content %, Preferably 0.3 to 5% by volume, distillation 90% point at 300 to 380 ° C, ASTM hue 0.1 to 1.0 and C in total sulfur compounds ₂ Dibenzothiophene and C ₃ A gas oil fraction having a property that the total ratio of dibenzothiophene is 40% by mass or less is used.
As described above, the gas oil fraction of the raw material is converted into C, which is a hardly desulfurized compound. ₂ Dibenzothiophene and C ₃ By specifying the ratio of the total amount of dibenzothiophene to the total sulfur compounds, the total aromatic content, the aromatic content of three or more rings, the basic nitrogen content, etc., the desulfurization reactivity is improved.
Said C ₂ Dibenzothiophene and C ₃ Dibenzothiophene refers to a compound in which the total carbon number of a hydrocarbon group as a substituent bonded to a dibenzothiophene ring is 2 and 3, respectively. In addition, the basic nitrogen refers to carbazole, quinoline, and the like. The method for measuring the properties of the gas oil fraction as the raw material will be described later.
As the gas oil fraction of the raw material having the above properties, a straight gas oil which is a gas oil fraction obtained from atmospheric distillation may be used alone, or the straight gas oil may be subjected to hydrodesulfurization treatment to obtain a sulfur component. May be used by recycling and blending a part of the gas oil fraction in which the oil content has been reduced. Alternatively, a hydrocarbon fraction of (1) to (5) shown below may be added to the straight-run gas oil in total amount. It is also possible to use those blended at a ratio of 40% by volume or less.
[0015]
(1) 0.01 to 0.1 mass% of sulfur content, density at 15 ° C 0.83 to 0.88 g / cm ³ A hydrocarbon fraction having properties of 35 to 45% by volume of total aromatics, 3 to 4% by volume of aromatics having three or more rings and a distillation 90% point of 320 to 360 ° C., for example, from a hydrodesulfurization apparatus for vacuum gas oil. Low sulfur gas oil fraction obtained.
(2) Sulfur content 0.01 to 0.1% by mass, nitrogen content 100 to 200 mass ppm, density at 15 ° C 0.83 to 0.90 g / cm ³ And a hydrocarbon fraction having a distillation 90% point of 320 to 380 ° C., for example, a low sulfur gas oil fraction obtained from a hydrodesulfurization unit for atmospheric residual oil.
(3) 0.1-0.8 mass% of sulfur content, 600-800 massppm of nitrogen content, and 0.88-0.98 g / cm at 15 ° C density ³ A hydrocarbon fraction having a distillation 90% point of 320 to 380 ° C. and a total aromatic content of 50 to 100% by volume, such as a gas oil fraction obtained from a catalytic cracking unit.
(4) 0.01-0.1% by mass of sulfur content, 100-500% by mass of nitrogen content, 15 ° C density 0.75-0.87g / cm ³ A hydrocarbon fraction having a distillation 90% point of 180 to 260 ° C. and a total aromatic content of 30 to 90% by volume, for example, a kerosene fraction obtained from a catalytic cracking unit.
(5) Sulfur content 0-50 mass ppm, 15 ° C density 0.80-0.85 g / cm ³ A hydrocarbon fraction having a distillation 90% point of 320 to 360 ° C. and a total aromatic content of 5 to 25% by volume, such as a gas oil fraction obtained from a heavy gas oil hydrocracking unit.
Thus, by blending various hydrocarbon oils having different properties with the straight-run gas oil based on the total amount, preferably at a ratio of 40% by volume or less, and adjusting the reactivity, the sulfur content is 15 mass ppm. The desulfurized gas oil having a concentration of 10 mass ppm or less can be efficiently obtained.
[0016]
It is more preferable that the hydrocarbon oils (1) to (4) are blended with the straight-run gas oil at a ratio of 30% by volume or less based on the total amount.
Next, a method for hydrodesulfurizing the gas oil fraction of the raw material having the above-mentioned properties by bringing the gas oil fraction into contact with the catalyst according to the present invention will be described.
The type of reaction is not particularly limited, and can be appropriately selected from various types such as a fixed bed, a moving bed, a boiling bed, and a suspended bed. Desulfurization treatment is performed. Further, as a distribution system of the gas oil fraction of the raw material, both a down flow system and an up flow system can be used.
The number of reaction zones [the number of packed catalyst layers (sometimes referred to as the number of stages)] may be one, or two or more. When the number of reaction zones is two or more, by performing hydrodesulfurization treatment by combining two or more kinds of catalysts in the order of relatively low hydrogen consumption catalyst to high hydrogen consumption catalyst, It is preferable because it is possible to effectively desulfurize a hardly desulfurizable sulfur compound and to obtain a desulfurized gas oil having a sulfur content reduced to a desired value or less.
[0017]
In general, Co-Mo based catalysts consume less hydrogen than Ni-Mo based catalysts. When Ti is included, the amount of hydrogen consumption increases, and when the amount of supported metal increases, the amount of hydrogen consumption increases.
Therefore, when two or more catalysts are combined, it is advantageous to use a catalyst containing titanium together with nickel, molybdenum and phosphorus after the second catalyst layer (second reaction zone). The ratio of the amount of catalyst in the first catalyst layer to the amount of catalyst in the second and subsequent catalyst layers is not particularly limited, but is usually 10:90 to 80:20, preferably 15:85 to 60:40 in terms of volume ratio. Is selected in the range.
As described above, by combining two or more kinds of catalysts and performing hydrodesulfurization treatment in a multi-stage reaction zone, the easily desulfurized sulfur compound is easily desulfurized by the catalyst having a high desulfurization activity in the first reaction zone. You. Then, after the second reaction zone, a catalyst having a high hydrogenation activity (high hydrogen consumption) is used to form a sulfur compound which is difficult to desulfurize. ₂ Dibenzothiophene and C ₃ By hydrogenation of the aromatic ring of dibenzothiophene, cleavage of the CS bond is promoted, and the above-mentioned hardly desulfurizable sulfur compound is effectively desulfurized.
[0018]
The reaction conditions in the hydrodesulfurization treatment of the present invention include a reaction temperature of 300 to 400 ° C. and an LHSV (liquid hourly space velocity) of 0.5 to 3.0 h. ^-1 , Preferably 0.5 to 2.0 h ^-1 , More preferably 0.5 to 1.5 h ^-1 , A hydrogen partial pressure of 3 to 10 MPa, preferably 4 to 8 MPa, and a hydrogen / oil ratio of 150 to 500 Nm. ³ / KL, preferably 200 to 400 Nm ³ / KL. Further, the hydrogen consumption is 30 to 70 Nm in order to suppress coke deterioration. ³ / KL is preferably controlled.
By hydrodesulfurizing the gas oil fraction of the raw material in this way, the ASTM hue is 0.1 to 2.5, and the sulfur content is reduced to 15 ppm by mass or less, preferably 10 ppm by mass or less. Light oil is obtained. The method for measuring the sulfur content of the desulfurized gas oil will be described later.
The present invention also provides a gas oil composition produced by the aforementioned gas oil hydrodesulfurization method.
The light oil composition of the present invention has a sulfur content reduced to 15 mass ppm or less, preferably 10 mass ppm or less, has little effect on air pollution, and particularly prolongs the life of an oxidation catalyst in a DPF of a diesel vehicle. This is effective for PM reduction.
[0019]
【Example】
Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In addition, each physical property was measured according to the method shown below.
<Catalyst>
(1) Specific surface area
It was measured by the BJH method (Barret-Joyner-Halenda) method.
<Raw oil distillate>
(1) Sulfur content
It was measured according to JIS K2541.
(2) Density
It was measured according to JIS K2249.
(3) Nitrogen content, basic nitrogen content
The nitrogen content is JIS K2609, and the basic nitrogen content is Anal. Chem. , 37, 54 (1965).
(4) Whole aromatics, aromatics with three or more rings
It measured based on JPI-5S-49 (The Japan Petroleum Institute method).
(5) Distillation 90% point
It was measured according to JIS K2254.
(6) ASTM hue
It was measured according to JIS K2580.
(7) C in total sulfur compounds ₂ Dibenzothiophene (C ₂ DBT) and C ₃ Dibenzothiophene (C ₃ DBT)
The measurement was performed using a GC-AED (gas chromatography-atomic emission detector).
<Desulfurized light oil>
(1) Sulfur content
It measured similarly to (1) in the gas oil fraction of the said raw material.
(2) ASTM hue
It measured similarly to (6) in the gas oil fraction of the said raw material.
(3) Nitrogen content
It measured similarly to (3) in the gas oil fraction of the said raw material.
Table 1 shows the properties of the feedstock oil used in each example, and Table 2 shows the properties of the catalyst.
[0020]
[Table 1]

[0021]
[Table 2]

[0022]
[note]
Feed oil A: straight-run gas oil (light oil fraction obtained from atmospheric distillation)
Raw light oil B ... Delighted light oil (light oil fraction obtained during hydrotreatment (desulfurization, mild cracking) of vacuum distillate)
Feed oil C ··· Directly removed light gas oil (light oil fraction obtained during hydrodesulfurization treatment of normal pressure residual oil)
Raw material D. Light cycle oil (Light cycle oil of RFCC, FCC)
Feedstock E: Kerosene fraction of fluid catalytic cracking (light light cycle oil of RFCC, FCC)
Feed oil F ・・ Hydrolysis gas oil (light oil fraction obtained during hydrocracking of vacuum distillate)
Feedstock G: straight-run gas oil (light oil fraction obtained from atmospheric distillation, heavier than feedstock A)
[0023]
[Table 3]

[0024]
[note]
The relative hydrogen consumption was determined for each catalyst under the same feedstock oil and reaction conditions as in Example 1, and the values when catalyst A was taken as 100 were shown.
Example 1
The raw material oil A having the properties shown in Table 1 was subjected to hydrodesulfurization treatment using the catalyst A shown in Table 2 under the reaction conditions shown in Table 3. Table 3 shows the sulfur content, ASTM hue, and nitrogen content of the obtained desulfurized gas oil.
[0025]
Example 2
The desulfurized gas oil A obtained in Example 1 was recycled and blended with the stock oil A at a rate of 30 vol% based on the total amount, and subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
Example 3
Hydrodesulfurization treatment was performed in the same manner as in Example 1 except that the first catalyst layer was filled with 25 vol% of catalyst B and the second catalyst layer was filled with 75 vol% of catalyst A. Table 3 shows the properties of the obtained desulfurized gas oil.
Example 4
Hydrodesulfurization treatment was carried out in the same manner as in Example 1, except that the first catalyst layer was filled with 20 vol% of catalyst B, the second catalyst layer with 20 vol% of catalyst C, and the third catalyst layer with 60 vol% of catalyst A. Table 3 shows the properties of the obtained desulfurized gas oil.
Example 5
A raw material A having the properties shown in Table 1 and a raw material B blended at 20 vol% based on the total amount were subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
[0026]
Example 6
The raw oil A having the properties shown in Table 1 and the raw oil C blended at 10 vol% based on the total amount were subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
Example 7
A raw material oil A having the properties shown in Table 1 and a mixture of 5 vol% of the raw material oil D based on the total amount were subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
Example 8
A raw material oil A having the properties shown in Table 1 and a mixture of 15 vol% of the raw material oil E based on the total amount were subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
Example 9
A raw oil A having the properties shown in Table 1 and a raw oil F blended at 20 vol% based on the total amount were subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
[0027]
Comparative Example 1
In Example 1, hydrodesulfurization treatment was performed in the same manner as in Example 1 except that the raw material oil G having the properties shown in Table 1 was used instead of the raw material oil A. Table 3 shows the properties of the obtained desulfurized gas oil.
Comparative Example 2
The hydrodesulfurization treatment was performed in the same manner as in Example 1 except that the reaction conditions in Example 1 were changed to those shown in Table 3. Table 3 shows the properties of the obtained desulfurized gas oil.
Comparative Example 3
A raw material oil A having the properties shown in Table 1 and a 70 vol% blend of the raw material oil D based on the total amount were subjected to hydrodesulfurization treatment in the same manner as in Example 1. Table 3 shows the properties of the obtained desulfurized gas oil.
[0028]
[Table 4]

[0029]
[Table 5]

[0030]
[Table 6]

[0031]
As can be seen by comparing Example 1 with Examples 3 and 4, catalysts are combined in the order of relatively low hydrogen consumption to high hydrogen consumption, and the reaction zone is increased to two or more stages. Thereby, the sulfur content of the obtained desulfurized gas oil is further reduced.
[0032]
【The invention's effect】
According to the present invention, a gas oil fraction used as a fuel oil for a diesel engine or the like is subjected to hydrodesulfurization treatment to efficiently and economically reduce its sulfur content to 15 mass ppm or less, preferably 10 mass ppm or less. At the same time, deterioration of hue can be suppressed.

Claims

Sulfur content 0.5 to 2.5 mass%, 15 ° C density 0.81 to 0.87 g / cm ³ , basic nitrogen content 10 to 200 massppm, total aromatic content 20 to 40 volume%, tricyclic or higher. The aromatic content is 0.1 to 10% by volume, the distillation 90% point is 300 to 380 ° C., the ASTM hue is 0.1 to 1.0, and the total ratio of C ₂ dibenzothiophene and C ₃ dibenzothiophene to all sulfur compounds is 40. A gas oil fraction having properties of not more than mass% is subjected to a reaction temperature of 300 to 400 ° C., an LHSV (liquid hourly space velocity) of 0.5 to 3.0 h ⁻¹ , a hydrogen partial pressure of 3 to 10 MPa, and a hydrogen / oil ratio of 150 to 500 Nm. Under a reaction condition of ³ / kL, a hydrodesulfurization treatment was carried out by bringing cobalt and / or nickel, molybdenum and phosphorus into contact with a catalyst supported on a refractory inorganic carrier in the coexistence of hydrogen, and the ASTM hue was reduced to 0. .1 Suppresses 2.5, hydrodesulfurization method gas oil, characterized in that to reduce the sulfur content to below 15 mass ppm.

The method for hydrodesulfurizing gas oil according to claim 1, wherein the sulfur content is reduced to 10 mass ppm or less.

Claim 1 or 2 hydrodesulfurization process of the gas oil according to hydrodesulfurization under conditions of hydrogen consumption 30~70Nm ³ / kL.

4. The gas oil hydrodesulfurization method according to claim 1, wherein a portion of the gas oil fraction with reduced sulfur content is recycled and subjected to hydrodesulfurization treatment.

The method for hydrodesulfurizing gas oil according to any one of claims 1 to 4, wherein at least two kinds of catalysts are combined and subjected to hydrodesulfurization treatment in the order of relatively low hydrogen consumption to high hydrogen consumption.

The method for hydrodesulfurizing gas oil according to claim 5, wherein when two or more kinds of catalysts are combined, hydrodesulfurization treatment is performed using a catalyst containing titanium together with nickel, molybdenum and phosphorus after the second catalyst layer.

The gas oil fraction used in the hydrodesulfurization treatment is such that the straight-run gas oil fraction has a sulfur content of 0.01 to 0.1% by mass, a 15 ° C density of 0.83 to 0.88 g / cm ³ , and a total aromatic content of 35 to A hydrocarbon fraction having a property of 45% by volume, 3 to 4% by volume of aromatics having three or more rings and a distillation 90% point of 320 to 360 ° C is added at a ratio of 40% by volume or less based on the total amount. The method for hydrodesulfurizing gas oil according to any one of claims 1 to 6.

The method for hydrodesulfurizing gas oil according to claim 7, wherein the hydrocarbon fraction is a low sulfur gas oil fraction obtained from a vacuum gas oil hydrodesulfurization unit.

The gas oil fraction used for the hydrodesulfurization treatment is such that the straight-run gas oil fraction has a sulfur content of 0.01 to 0.1% by mass, a nitrogen content of 100 to 200 mass ppm, and a density at 15 ° C of 0.83 to 0.90 g / cm. The gas oil according to any one of claims 1 to 6, wherein a hydrocarbon fraction having a property of ³ and a distillation 90% point of 320 to 380 ° C is added at a ratio of 40% by volume or less based on the total amount. Hydrodesulfurization method.

The gas oil hydrodesulfurization method according to claim 9, wherein the hydrocarbon fraction is a low sulfur gas oil fraction obtained from a normal pressure residual oil hydrodesulfurization unit.

The gas oil fraction used for the hydrodesulfurization treatment is such that the straight-run gas oil fraction has a sulfur content of 0.1 to 0.8% by mass, a nitrogen content of 600 to 800 mass ppm, and a density at 15 ° C of 0.88 to 0.98 g / cm. ^3. A hydrocarbon fraction having a distillation 90% point of 320 to 380 ° C. and a total aromatic content of 50 to 100% by volume is added at a ratio of 30% by volume or less based on the total amount. 7. The method for hydrodesulfurizing gas oil according to any one of claims 6 to 6.

The method for hydrodesulfurizing gas oil according to claim 11, wherein the hydrocarbon fraction is a gas oil fraction obtained from a catalytic cracking unit.

The gas oil fraction used in the hydrodesulfurization treatment is such that a straight-run gas oil fraction has a sulfur content of 0.01 to 0.1% by mass, a nitrogen content of 100 to 500 ppm by mass, and a 15 ° C density of 0.75 to 0.87 g / cm. ^3. A hydrocarbon fraction having ^a distillation 90% point of 180 to 260 ° C. and a total aromatic content of 30 to 90% by volume is added at a ratio of 40% by volume or less based on the total amount. 7. The method for hydrodesulfurizing gas oil according to any one of claims 6 to 6.

14. The method for hydrodesulfurizing gas oil according to claim 13, wherein the hydrocarbon fraction is a kerosene fraction obtained from a catalytic cracking unit.

The gas oil fraction used in the hydrodesulfurization treatment is such that the straight-run gas oil fraction has a sulfur content of 0 to 50 mass ppm, a density of 15 ° C of 0.80 to 0.85 g / cm ³ , a distillation 90% point of 320 to 360 ° C and The hydrodesulfurization of a gas oil according to any one of claims 1 to 6, wherein a hydrocarbon fraction having a property of a total aromatic content of 5 to 25% by volume is added at a ratio of 40% by volume or less based on the total amount. Method.

The method for hydrodesulfurizing gas oil according to claim 15, wherein the hydrocarbon fraction is a gas oil fraction obtained from a heavy gas oil hydrocracking apparatus.

A gas oil composition produced by the hydrodesulfurization method according to any one of claims 1 to 16.