JP4425403B2 - Olefin polymerization process - Google Patents

Description

【００２３】
好適な環式オレフィン類及び置換された環式オレフィン類の例としては、シクロペンテン、１−メチルシクロペンテン及びシクロヘキセンが挙げられる。式Ｉのタイプの好適なオレフィン類の例としては、プロペン、２−メチルプロペン、１−ブテン、２−ブテン、２−メチル−１−ブテン、３−メチル−１−ブテン、２−メチル−２−ブテン、２，３−ジメチル−１−ブテン、３，３−ジメチル−１−ブテン、２，３−ジメチル−２−ブテン、２−エチル−１−ブテン、１−ペンテン、２−ペンテン、２−メチル−１−ペンテン、３−メチル−１−ペンテン、４−メチル−１−ペンテン、１−ヘキセン、２−ヘキセン、及び３−ヘキセンが挙げられる。
【００２４】
本発明のオレフィン転換プロセスの実施で使用する好ましいオレフィン類は炭素原子３〜６個を含み、非常に好ましいオレフィン類は炭素原子３または４個を含む。所望により、本発明のオレフィン転換プロセス用の第１及び第２のオレフィン−含有供給原料は、異なるオレフィン類の混合物を含み得る。或いは、第１及び第２の供給原料のいずれかまたは両方は単一種のオレフィン類から構成されていてもよい。第１及び第２の供給原料は、オレフィン類以外の物質、例えば、重合プロセスで使用する反応条件下で実質的に不活性の希釈剤を含み得ると考えられる。例えば、第１及び第２の供給原料のいずれかまたは両方は、本発明のオレフィン転換プロセスの条件下で比較的非反応性である実質的な量の飽和炭化水素類、例えば、直鎖パラフィン類を含むことができる。実際、直鎖パラフィン（例えば、プロパンまたはブタン）は希釈剤として及び、発熱性オレフィン転換反応により生成する熱を処理する際に使用するリサイクル物質として使用することができる。
【００２５】
第１のオレフィン−含有供給原料は、あるとしても殆ど芳香族化合物を含まないオレフィン重合プロセス用の慣用の供給原料である。本発明の一態様では、第１のオレフィン−含有供給原料は実質的に芳香族化合物を含まない。しかしながら、所望により、第１のオレフィン−含有供給原料は少量の１種以上の芳香族化合物を含むことができる。芳香族成分が存在する場合、第１のオレフィン−含有供給原料のオレフィンまたはオレフィン類によるこれらの成分のアルキル化はオレフィン重合と同時に実施することができる。望ましくは、第１のオレフィン−含有供給原料中のオレフィン類対芳香族化合物のモル比は少なくとも約１２であり、好ましくは少なくとも約１５であり、より好ましくは少なくとも約１８である。かかる態様では、毒性のためガソリン成分として不都合な揮発性低分子量芳香族化合物（例えば、ベンゼン）は、アルキル化によって非常に望ましいガソリン成分である揮発性の低い物質に転換することができる。例えば、ベンゼン及びトルエンは、プロペンとのモノアルキル化によりそれぞれクメン及びシメンに転換することができる。オレフィン重合と芳香族のアルキル化の混成は、ガソリンブレンド用原料の製造で使用するのに特に望ましいプロセスである。かかる態様では、炭素原子３または４個を含有する低分子量オレフィン類を使用してベンゼンをアルキル化し、過剰のオレフィン類をオリゴマーに転換することができる。これらの生成物は全てハイオクタンであり、望ましいガソリン成分である。
【００２６】
第１のオレフィン−含有供給原料に配合できる芳香族化合物としては、酸触媒の存在下でオレフィンによりアルキル化することができ、芳香族官能基を含有する炭素原子６〜２０個の全ての有機化合物が挙げられる。そのような物質としては、芳香族化合物及び１個以上の置換基を持つ置換芳香族化合物のいずれもが挙げられる。炭素原子６〜１０個を有する芳香族炭化水素類及びヒドロカルビル−置換芳香族炭化水素類が特に好ましい。さらに、かかる物質の混合物も本発明の実施における第１のオレフィン−含有供給原料の成分として使用することができる。かかる物質の例としては、炭素原子６〜２０個を含有する式ＩＩ（式中、Ｒはそれぞれ独立して水素及びヒドロカルビル基からなる群から選択される）の化合物が挙げられる。しかしながら、好ましい芳香族化合物は、炭素原子６〜１０個を含有する炭化水素類であり、式ＩＩ（式中、Ｒはそれぞれ独立して水素及び炭素原子１〜３個のアルキルからなる群から選択される）の化合物である。ベンゼン及びトルエンが特に好ましい。
【００２７】
【化２】

【００２８】
本発明のオレフィン重合プロセスに加える第１のオレフィン−含有供給原料中に含まれる芳香族化合物は任意の所望の供給源により得ることができる。しかしながら、オレフィン重合プロセスによりガソリンブレンド用原料を石油精製所で製造する場合には、改良装置及び単離装置が芳香族成分の都合のよい供給源である。例えば、軽質改質油を使用することができ、この種の典型的な材料は約３５容積％の全芳香族含量を有し、約１０容積％のベンゼンを含む。かかる軽質改質油約１０容積％と、プロパンとブタン類とを混合したプロピレンとブチレン類約４５容積％を含有するＣ₃〜Ｃ₄供給原料約９０容積％とを混合することにより第１のオレフィン−含有供給原料を製造する場合、この供給原料中のベンゼンの約８０％は固体リン酸触媒を使用する慣用のオレフィン重合装置でアルキル化することができる。
【００２９】
本発明の実施において、ガソリン沸点範囲のオリゴマーに転換するための重合装置に典型的な第１のオレフィン−含有供給原料は、オレフィン濃度が約３５容積％〜約６０容積％の範囲のプロパン、ブタン、１−メチルプロパン、プロペン、１−ブテン、２−ブテン及び１−メチルプロペンの混合物を含む。しかしながら、第１のオレフィン−含有供給原料は、これらに限定されないが、他のオレフィン類またはオレフィン混合物、他の希釈剤を含む他の種々の成分と、少量の芳香族化合物とを含むことができる。さらに、オレフィン濃度は、この範囲外であっても使用することができる。
【００３０】
本発明の実施で使用する第２のオレフィン−含有供給原料は、第１の供給原料中での任意の低濃度の芳香族化合物よりもかなり高濃度の芳香族化合物を含むという点で、第１のオレフィン−含有供給原料とは異なる。望ましくは、第２のオレフィン−含有供給原料中のオレフィン類対芳香族化合物のモル比は、約１〜約１０、好ましくは約２〜約８、より好ましくは約３〜約８である。
【００３１】
第２のオレフィン−含有供給原料中に配合できる芳香族化合物は、第１のオレフィン−供給原料中で使用するのに好適なものと同じである。上述の如く、これらの芳香族化合物としては、芳香族官能基を含み、酸触媒の存在下でオレフィンによりアルキル化することができる炭素原子６〜２０個の全ての有機化合物が挙げられる。かかる物質としては、芳香族化合物及び１つ以上の置換基をもつ置換芳香族化合物のいずれもが含まれる。芳香族炭化水素類及び炭素原子６〜１０個を含むヒドロカルビル−置換芳香族炭化水素類が特に望ましい。第２のオレフィン−含有供給原料の成分として使用するのに好ましい芳香族化合物は、Ｒがそれぞれ独立して水素及び炭素原子１〜３個のアルキルからなる群から選択される式ＩＩの化合物である。さらに、好ましい芳香族化合物は、大気圧で約２０℃〜約２５０℃の範囲の沸点を有する液体である。ベンゼン及びトルエンが特に好ましい。
【００３２】
本発明のオレフィン重合プロセスに加える第２のオレフィン−含有供給原料に含まれる芳香族化合物は、任意の所望の供給源により得ることができる。しかしながら、上述の如く、ガソリンブレンド用原料をオレフィン重合プロセスにより石油精製所で製造する場合、接触分解装置、精製所及び単離装置が芳香族成分の都合のよい供給源である。軽質改質油は好適な芳香族化合物の非常に望ましい供給源であり、この種の典型的な材料は約３５容積％の全芳香族含量を含み、ベンゼン約１０容積％を含む。
【００３３】
本発明の一態様では、第２のオレフィン−含有供給原料は、大気圧で約２０℃〜約２５０℃の範囲で沸騰し、少なくとも約５容積％の芳香族成分を含む実質的にオレフィンを含まない炭化水素流体約２０〜約８０容積％から構成される（この炭化水素流体は本明細書中、「実質的にオレフィンを含まない炭化水素流体」と参照される）。例えば、第２の供給原料は第１の供給原料の約２０〜約８０容積％を実質的にオレフィンを含まない炭化水素流体と交換することにより製造することができる。実質的にオレフィンを含まない炭化水素流体は約２０℃〜約２５０℃の範囲で沸騰するのが望ましいが、好ましい範囲は約２０℃〜約１８０℃であり、より好ましい範囲は約３０℃〜約１３０℃である。さらにこの流体は少なくとも約５容積％の芳香族成分、好ましくは少なくとも約２０容積％の芳香族成分、より好ましくは少なくとも約３０容積％の芳香族成分を含む。典型的にはこの流体は約１５〜約８５容積％の芳香族成分を含む。最終的に、実質的にオレフィンを含まない炭化水素流体は、５容積％未満、好ましくは３容積％未満、より好ましくは２容積％未満のオレフィン含量を有する。
【００３４】
石油精製所では、実質的にオレフィンを含まない炭化水素流体として、ナフサ、改質油及び芳香族と脂肪族炭化水素類のブレンドを使用することができる。しかしながら、改質油が好ましい。本発明の実施で使用するのに好適な典型的な軽質改質油は、オレフィン類約０〜約２容積％、芳香族成分約２０〜約４５容積％を含み、１０％蒸留点（Ｔ１０）が約１６０゜F（７１℃）以下であり、５０％蒸留展（Ｔ５０）が２００゜F（９３℃）以下であり、９０％蒸留点（Ｔ９０）が約２５０゜F（１２１℃）以下であるような蒸留特性を有する。これらの蒸留点は、ＡＳＴＭ Ｄ８６−９５方法（１９９６ Ａｎｎｕａｌ Ｂｏｏｋ ｏｆＡＳＴＭ Ｓｔａｎｄａｒｄｓ, 第５章、Ｐｅｔｒｏｌｅｕｍ Ｐｒｏｄｕｃｔｓ、Ｌｕｂｒｉｃａｎｔｓ, ａｎｄ Ｆｏｓｓｉｌ Ｆｕｅｌｓに知見することができる）によりまたは慣用の代替方法により得られる蒸留点を指すものと理解される。典型的な軽質改質油はベンゼン約５〜約１５容積％を含む。
【００３５】
実質的にオレフィンを含まない炭化水素流体の芳香族成分は非常に重要であり、第２のオレフィン−含有供給原料の成分として使用するのが好適なものとしては上記のタイプのものがある。
【００３６】
本発明の第２のオレフィン−含有供給原料は、第１のオレフィン−含有供給原料の一部を実質的にオレフィンを含まない炭化水素流体で置き換えることにより製造し、前記流体は、得られた混合物中のオレフィン類対芳香族成分のモル比が約１〜約１０の範囲であるようにするのに効果的な量で使用する。
【００３７】
オレフィン重合を触媒することができる任意の固体酸性物質を本発明の実施での触媒として使用することができ、かかる物質としては、固体支持体上に担持された液体酸が挙げられる。固体酸触媒は、オレフィン類による芳香族化合物のアルキル化を触媒する能力も持つのが望ましい。実際には、オレフィン重合プロセスを触媒することができる殆どの固体酸物質がこの能力を持つ。本発明のオレフィン重合プロセスの実施では、オレフィン−含有供給原料を好適な温度及び圧力で固体酸触媒の微粒子固定床上に容易に通すことができる。
【００３８】
本発明の実施で使用するのが好適な触媒は、酸性ポリマー樹脂、担持された酸、及び酸性無機酸化物などの物質から構成することができる。好適な酸性ポリマー樹脂の例としては、当業者に公知で市販されているポリマー性スルホン酸樹脂が挙げられる。Ａｍｂｅｒｌｙｓｔ（登録商標）３５（Ｒｏｈｍ ａｎｄ Ｈａａｓ製）はかかる物質の典型例である。
【００３９】
触媒として有用な担持酸としては、固体（例えば、シリカ、アルミナ、シリカ−アルミナ、酸化ジルコニウムまたはクレー）上に担持されているブロンステッド酸（例えば、リン酸、硫酸、硼酸、ＨＦ、フルオロスルホン酸、トリフルオロメタンスルホン酸、及びジヒドロキシフルオロ硼酸）及びルイス酸（例えば、ＢＦ₃、ＢＣｌ₃、ＡｌＣｌ₃、ＡｌＢｒ₃、ＦｅＣｌ₂、ＦｅＣｌ₃、ＺｎＣｌ₂、ＳｂＦ₅、ＳｂＣｌ₅及びＡｌＣｌ₃とＨＣｌとの組合せ）が挙げられるが、これらに限定されない。液体酸を使用する場合には、担持触媒は、通常、所望の液体酸と所望の担体とを混合し、次いで乾燥することにより製造する。
【００４０】
触媒として有用な酸性無機酸化物としては、アルミナ、シリカ−アルミナ、天然及び合成ピラークレー（ｐｉｌｌａｒｅｄ ｃｌａｙ）、並びに天然及び合成ゼオライト（例えば、ファウジャサイト；ｆａｕｊａｓｉｔｅｓ、モルデナイト、Ｌ、オメガ、Ｘ、Ｙ、ベータ、及びＺＳＭ）が挙げられるが、これらに限定されない。非常に好適なゼオライトとしては、ベータ、Ｙ、ＺＳＭ−３、ＺＳＭ−４、ＺＳＭ−５、ＺＳＭ−１８及びＺＳＭ−２０が挙げられる。所望によりゼオライトは無機酸化物マトリックス物質（例えば、シリカ−アルミナ）中に含ませることができる。
【００４１】
触媒は、種々の物質、例えば、ルイス酸（例えば、ＢＦ₃、ＢＣｌ₃、及びＡｌＣｌ₃）、非ゼオライト固体無機酸化物（例えば、シリカ、アルミナ及びシリカ−アルミナ）、並びに大孔（ｌａｒｇｅ ｐｏｒｅ）結晶質モレキュラーシーブ（例えば、ゼオライト、ピラークレー及びアルミノリン酸塩）の混合物を含むことができる。
【００４２】
リン酸と担体とを混合することにより製造する担持触媒はオレフィン重合プロセスではよく用いられ、本発明の実施で使用するのに非常に好ましい。かかる触媒は、本明細書中、固体リン酸触媒と参照する。
【００４３】
固体リン酸触媒は、通常、リン酸（例えば、オルト−リン酸、ピロ−リン酸またはテトラ−リン酸）と珪酸含有固体担体とを混合してウエットペーストを形成することにより製造する。このペーストをカ焼し、次いで粉砕して触媒粒子とするか、より均一な触媒粒子を製造するためにカ焼前にペーストを押し出すかペレット化することができる。担体は通常、天然の、多孔質シリカ−含有物質（例えば、珪藻土、カオリン、滴虫土または珪藻土）である。少量の種々の添加剤（例えば、鉱物性タルク、フラー土及び鉄化合物、例えば酸化鉄を含む）を担体に添加してその強度及び硬度を高めることができる。担体と添加剤との組合せは、通常、触媒の約１５〜３０重量％を構成し、残余はリン酸である。しかしながら、触媒の製造で使用するリン酸の量は、触媒の約８〜約８０重量％を変動することができる。固体リン酸触媒は市販されており、かかる物質はＵＯＰより商品名ＳＰＡ−２として市販されている。このＳＰＡ−２触媒は以下の特性：（１）公称直径４．７５ｍｍ；（２）充填密度０．９３ｇ／ｃｍ³；（３）Ｐ₂Ｏ₅として計算して遊離リン酸含量１６〜２０重量％；及び（４）Ｐ₂Ｏ₅として計算して公称全リン酸含量６０重量％を有する円柱状押出物である。慣用の固体リン酸触媒の製造及び特性は、米国特許第２，１２０，７０２号（Ｉｐａｔｉｅｆｆら）；同第３，０５０，４７２号（Ｍｏｒｒｅｌｌ）；同第３，０５０，４７３号（Ｍｏｒｒｅｌｌ）及び同第３，１３２，１０９号（Ｍｏｒｒｅｌｌ）；並びに英国特許第８６３，５３９号に示されている。これらの特許は、本明細書中参照として含まれる。
【００４４】
本発明のオレフィン重合プロセスは、固体酸触媒の固定床中で実施する。所望により、触媒はチャンバ反応器またはチューブラ反応器中に配置することができる。チューブラ反応器では、触媒は循環する冷却剤で取り囲まれているたくさんの小さな管の中に入れられる。これらの管は通常、約５ｃｍ〜約１５ｃｍの内径を有するが、他の直径も使用することができる。反応器温度を厳しく管理することができ、高圧操作用に容易に製造することができるため、チューブラ反応器はチャンバ反応器よりも望ましいことが多い。通常、複数の反応器を使用する。例えば、チューブラ反応器を使用するオレフィン重合装置は、８つ以上もの多くの反応器を使用することができる。反応器内の多くの触媒床の間のクエンチとして及び／または反応器流出物から反応器供給原料へのリサイクルとして飽和炭化水素を使用することにより、発熱性オレフィン転換反応器により発生した熱をチャンバ反応器内で制御することができる。チューブラ反応器内の温度は、通常、反応器管回りの水または油循環により制御される。
【００４５】
本発明のオレフィン重合プロセスの実施において、第１の供給原料のオレフィン類の少なくとも一部を所望の生成物（例えば、ガソリンブレンド用原料としてまたは石油化学供給原料として有用なオリゴマー）に転換するのに有効な温度、圧力及び時間、第１のオレフィン−含有供給原料を固体酸触媒と接触させる。望ましくは、接触温度は約５０℃を超え、好ましくは１００℃を超え、より好ましくは１２５℃を超える。通常、接触は約５０℃〜約３５０℃、好ましくは約１００℃〜約３５０℃、より好ましくは約１２５℃〜約２５０℃の範囲の温度で実施する。勿論、最適温度は使用する特定の固体酸触媒及び特定のオレフィン類、第１の供給原料中のそれらの濃度の関数である。しかしながら、プロピレン及び／またはブチレン類と組み合わせて使用する典型的な固体リン酸触媒の場合には、通常、反応温度は約１５０℃〜約２５０℃の範囲である。
【００４６】
本発明のオレフィン重合プロセスの実施では、第１のオレフィン−含有供給原料を任意の好適な圧力で固体酸触媒と接触させることができる。しかしながら、約０．０１〜約２００気圧の範囲の圧力が望ましく、約１〜約１００気圧の範囲の気圧が好ましい。典型的な固体リン酸触媒をプロピレン類及び／またはブチレン類のガソリンブレンド用原料への転換に使用する場合、圧力は通常、約２０から約９０気圧の範囲である。
【００４７】
このプロセスの実施において、第１のオレフィン−含有供給原料を固定床内に通し、オレフィンポリマーから構成される生成物流を固定床から取り出すことによって、オレフィン重合条件下で第１のオレフィン−含有供給原料と固体酸触媒の固定床とを接触させる。この接触により、時間が経過するにつれて酸触媒は失活する。
【００４８】
第１のオレフィン−含有供給原料中のオレフィンの少なくとも一部をオレフィンポリマーに転換させるための本発明の実施において好適な温度及び圧力の上記条件は、本明細書中、「オレフィン重合条件」と参照する。本発明の第２のオレフィン−含有供給原料を触媒の固定床と接触させる際にも、これらの同一オレフィン重合条件を使用する。特に、第２の供給原料を固定床に通し、固定床から生成物を取り出すことによって、オレフィン重合条件下で供給原料を固体酸触媒の固定床と接触させる。前記第２の供給原料との接触開始時に対し高い活性を持つ再生酸触媒を製造するのに有効な時間、第２の供給原料との接触を継続する。
【００４９】
本発明の一態様では、一方の供給原料を他方の供給原料で置き換える際に固体酸触媒の固定床内に供給原料の実質的に一定流を保持する（即ち、いずれの供給原料に対しても同一流量を使用する）。本発明の別の態様では、一方の供給原料を他方の供給原料で置き換える際に固体酸触媒の固定床内に実質的に一定温度及び圧力を保持する（即ち、いずれの供給原料に対しても同一温度及び圧力を使用する）。
【００５０】
オレフィン類の重合を触媒するのに好適な殆どの固体酸触媒は、オレフィン類の重合と同様または同一反応条件下でオレフィンによる芳香族化合物のアルキル化を促進するための優れた触媒でもある。第２のオレフィン−含有供給原料が芳香族化合物を含むことを考慮すると、供給原料中のオレフィンまたはオレフィン類によるこれらの芳香族化合物のアルキル化はオレフィン重合と競合する。結果としてオレフィンポリマーとアルキル化芳香族化合物とが生成物として得られ、これらの生成物の割合は、第２のオレフィン−含有供給原料中のオレフィン類対芳香族化合物のモル比の関数である。例えば、オレフィン対芳香族化合物のモル比が１である場合、芳香族化合物のアルキル化による生成物の形成は、オレフィン重合生成物の形成よりも優勢である。しかしながら、オレフィン類対芳香族化合物のモル比が約１０である場合には、オレフィンポリマーの形成が通常優勢である。
【００５１】
上述の如く、毒性のためガソリン成分としては望ましくない揮発性低分子量芳香族化合物（例えば、ベンゼン）を、アルキル化によってガソリン成分として非常に望ましいより揮発性の低い物質に転換することができる。重合とアルキル化のそのような組合せは、生成物をガソリンブレンド用原料として使用する場合には特に望ましい。
【００５２】
本発明の好ましい態様では、第１の供給原料がプロセスの主な供給原料であり、触媒の固定床の再生が必要な度に第２の供給原料で第１の供給原料を定期的に置換する連続プロセスを実施する。
【００５３】
慣用のオレフィン−含有供給原料を使用して触媒の固定床でオレフィン重合の間に起きる触媒失活は、副生成物として高沸点ポリマーが形成することに主に起因すると考えられている。これらの副生成物は触媒中に残存し、重質タールに似て、コークス様物質の外観さえ有するより高分子量ポリマーにさらに転換することがある。これらの物質は触媒粒子を覆い、触媒の孔を閉塞して触媒を失活させてしまう。時折、不純物がオレフィン−含有供給原料中に生じて触媒を失活させてしまうこともある。そのような不純物としては、エーテル類（例えば、ジメチルエーテル及びメチルイソプロピルエーテル）が挙げられるが、これらに限定されない。これらのエーテル類が触媒上に吸着することによって触媒を失活させてしまうことがあると考えられている。
【００５４】
その比較的高い芳香族成分の含量により、本発明の第２の供給原料は第１の供給原料よりも優れた溶媒である。従って、第２の供給原料は第１の供給原料よりも、以下の点：（１）触媒由来のタール及び不都合なポリマーを溶解または溶出し；及び（２）触媒から他の全ての吸着した触媒毒を取り除く；という点でより効果的であると考えられる。２つの供給原料を、例えば、触媒上での第１の供給原料中のオレフィン重合に使用するような高温で接触させる場合、第２の供給原料により失活触媒から失活性物質を除去するのは最も有効である。
【００５５】
【実施例】
二量体または三量体への転換によるＣ₃及びＣ₄オレフィン類のハイオクタンガソリンブレンド用原料への転換を、８つのチューブラ反応器（反応器Ａ〜Ｈと識別する）を含む重合装置で固体リン酸触媒（ＳＰＡ−２、ＵＯＰ製）上で実施した。しかしながら、反応器の一つ（反応器Ｄ）はこの実験の時点では休止中であった。少量の軽質改質油（通常、約１０〜約２３容積％）とオレフィン−含有Ｃ₃〜Ｃ₄流とをブレンドすることにより装置への通常の供給原料を製造した。通常の供給原料を使用して長期間にわたって重合装置を操作すると、触媒は著しく失活した。
【００５６】
多量の軽質改質油とオレフィン−含有Ｃ₃〜Ｃ₄流とをブレンドすることにより再生供給原料を製造し、この再生供給原料を８時間、通常の供給原料と置換した。８時間の再生期間の終了時には、通常の供給原料を使用して重合装置の操作を再開始した。再生供給原料の使用開始７時間前と、再生供給原料の使用停止９時間後で測定した通常の供給原料を用いる重合装置の操作条件を表Ｉに示す。再生期間７時間前、再生期間中、及び再生期間９時間後のオレフィン−含有Ｃ₃〜Ｃ₄流と軽質改質油との組成を表ＩＩ及びＩＩＩにそれぞれ示す。これらの組成は、触媒再生期間前のかなりの時間及び触媒失活が起きる間重合装置で使用したオレフィン−含有Ｃ₃〜Ｃ₄流及び軽質改質油に典型的である。
【００５７】
８時間の再生期間にわたり、重合装置に充填された軽質改質油の量は９００〜３８００ｂｐｄ（１４３，１００〜６０４，１００リットル／日）を変動し、平均は２７６５ｂｐｄ（４３９，６００リットル／日）であった。同じ再生期間の間、重合装置に充填されたＣ₃〜Ｃ₄流の量は２５１９〜６４５９ｂｐｄ（４００，５００〜１，０２６，９００リットル／日）を変動し、平均は３６９９ｂｐｄ（５８８，１００リットル／日）であった。従って、８時間の再生期間にわたり再生供給原料は軽質改質油約４３容積％からなり、芳香族成分約１３．９容積％及びＣ₃〜Ｃ₄オレフィン類約２２．７容積％を含んでいた。再生試験期間中の軽質改質油の流速が上記の如く変動したのは、サージドラムと揚水の制約のせいである。
【００５８】
再生期間の間、再生供給原料中のオレフィン類の転換により、再生期間の少し前及び少し後で通常の供給原料を使用して重合装置を操作した場合に知見される１８６℃〜１９６℃の温度に対して、反応器の内温を１８６℃〜１８８℃で本質的に変えることなく保持するのに十分な反応熱が得られた。再生期間の反応器の外温は、再生期間の前後での温度と実質的に同一であった。再生期間の内圧は平均して８０．８気圧ゲージであった。
【００５９】
重合装置の反応器中の触媒活性を（１）再生供給原料の使用開始７時間前と；（２）再生供給原料の使用完了９時間後で測定した。これらの活性値を表ＩＶに示すが、これらは問題となっている反応器のＣ₃及びＣ₄オレフィン類の転換の見かけの速度定数から計算した。見かけの速度定数は、反応器供給原料及び流出液のガスクロマトグラフィーによる分析から得られたデータを元にした。表ＩＶのデータは、再生方法により７つの反応器のうち６つの反応器において触媒活性が上昇したことを示した。活性は平均してかなり改良され、反応器Ａでの１０．６％から反応器Ｅでの７０．０％に及ぶ。
【００６０】
【表１】

【００６１】
【表２】

【００６２】
【表３】

【００６３】
【表４】

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a process for the polymerization of olefins on a fixed bed of solid acid catalyst. In particular, the present invention relates to an improved process for carrying out a process involving catalyst reactivation while simultaneously using the catalyst as an olefin conversion catalyst.
[0002]
[Problems to be solved by the invention]
Various industrial and petrochemical processes include condensation reactions of olefins or mixtures of olefins over acid catalysts to form high molecular weight products. In this specification, this type of condensation reaction is referred to as a polymerization process and the product is referred to as a low molecular weight oligomer or high molecular weight polymer. Oligomers are formed by condensation of 2, 3 or 4 olefin molecules with each other, and polymers are formed by condensation of 5 or more olefin molecules with each other. The term “polymerization” as used herein shall be used in reference to the formation process of oligomers and / or polymers.
[0003]
Low molecular weight olefins (eg, propene, 2-methylpropene, 1-butene and 2-butene) are composed of oligomers by polymerization on solid acid catalysts (eg, solid phosphoric acid catalysts), alcohols, detergents And can be converted into important products as starting materials for the production of chemical intermediates and final products, including plastics, and as raw materials for high-octane gasoline blends. Such a process is usually carried out on a fixed bed of solid acid catalyst at high temperature and pressure in a chamber reactor or tubular reactor. In order to carry out such a process, it is usually necessary to have several reactors in order not to replace the catalyst without shutting down the other reactors in the process equipment or to shut down individual reactors for other maintenance. Use a reactor. Furthermore, the reaction conditions in the process equipment can be optimized through the continuous use of two or more reactors.
[0004]
Acid-catalyzed alkylation of aromatic compounds with olefins is a known reaction of industrial importance. For example, ethylbenzene, cumene and detergent alkylates can be substituted with benzene for ethylene, propylene and C, respectively. _Ten ~ C ₁₈ Produced by alkylation with olefins. Sulfuric acid, HF, phosphoric acid, aluminum chloride, and boron fluoride are conventional catalysts for this reaction. In addition, solid acid catalysts with similar acid strength can be used to catalyze this process, such as amorphous and crystalline aluminosilicates, clays, ion-exchange resins, solid oxides and supported acids. (For example, solid phosphoric acid catalyst).
[0005]
When using a solid bed of a solid acid catalyst to catalyze the polymerization of olefins, the catalyst is usually gradually deactivated. Furthermore, catalyst deactivation may be accompanied by a strong pressure drop in the catalyst bed. Catalyst deactivation is known as a decrease in catalyst activity over time, usually due to the formation of by-products that accumulate on the catalyst surface or in the pores of the catalyst. These by-products have the effect of enveloping the catalyst, thus delaying contact between the new reactants in the feed and the catalyst or preventing the reactants from contacting the catalyst. Usually, the pressure drop across the catalyst bed increases with catalyst deactivation because the by-products adhere to the voids between the catalyst particles. Usually, from an economic point of view, the catalyst must be regenerated or replaced with a new catalyst after a certain level of catalyst deactivation and / or pressure drop in the catalyst bed has increased.
[0006]
The choice of replacing or regenerating the deactivated catalyst depends on various factors including the cost of the new catalyst, the disposal cost of the deactivated catalyst when discarded, the cost and effectiveness of the catalyst regeneration process. In particular, the length of time that the polymerization equipment must be shut down to replace or regenerate the deactivated catalyst is an important issue. Stopping the polymerization equipment for this purpose is very economically disadvantageous, so the downtime must be as short as possible.
[0007]
In the case of an olefin polymerization apparatus operating with a solid phosphoric acid catalyst, the deactivated catalyst is usually discarded and replaced with a new catalyst. Since solid phosphoric acid catalysts are relatively inexpensive, it is usually not beneficial to choose to regenerate satisfactorily for this type of catalyst. Therefore, from an economic point of view, catalyst replacement is usually indicated rather than regeneration.
[0008]
U.S. Pat. No. 4,028,430 (Stine et al.) Describes a simulated moving catalyst bed for simultaneous catalytic reaction in one region of a catalyst bed containing at least three regions and catalyst regeneration in another region. It relates to a continuous catalytic reaction process using moving catalyst). Each adjacent region is connected, and the regions are arranged in series in a fluid flow path in which the first and last regions are continuous. By periodically changing the composition of the fluid passing through each zone, the site of catalytic reaction and the location of catalyst reactivation are periodically moved from one continuous zone to the next, and a simulated moving catalyst bed Process can be provided. It is disclosed that this process can be applied to catalytic reactions such as alkylation, diolefin saturation, hydrocracking, catalytic cracking, desulfurization, dehydrogenation, polymerization, isomerization, reforming and flue gas desulfurization. ing. Further, one preferred type of reactivation is disclosed that tars, polymers, high molecular weight hydrocarbons, residues, or particulate matter may be washed away from the catalyst with a suitable solubilizer or flushing agent.
[0009]
Canadian Patent No. 1,055,921 (Burton et al.) Discloses that a solid acid catalyst bed deactivated by the deposition of polymerized and carbonized hydrocarbonaceous material on catalyst particles comprises: (a) In a liquid mixture for reactivation of hydrocarbons containing at least 5% aromatic components and boiling in the range of 40 ° C. to 230 ° C., a temperature of 40 ° C. to 37 ° C. and 1 and 1/3 Immersing the deactivated catalyst at a pressure of ˜100 absolute atmospheric pressure; (b) recovering the reactivation liquid from the catalyst; and then (c) repeating steps (a) and (b) at least once or more in situ. It is disclosed that it can be reactivated. Furthermore, it is disclosed that the catalyst reformed oil can be used as a reactivation liquid, and the deactivated catalyst is derived from a polymerization apparatus and can be used to produce motor fuel from light olefinic gas. To do. U.S. Pat. No. 4,062,801 (Burton et al.) Describes the following: (1) immersing the catalyst bed in a hot aromatic hydrocarbon-containing liquid by passing the fluid upward through the catalyst bed; 2) soak the catalyst bed in the liquid for at least 30 minutes at a temperature above about 280 ° F .; then (3) drain the liquid from the catalyst; A similar process involving replay is disclosed.
[0010]
US Pat. No. 5,648,579 (Kulpratipnja et al.) Prevents catalyst deactivation by using a periodic regeneration cycle, which cleans the catalyst-derived deactivated material with a desorbent. A continuous process for carrying out the catalytic reaction in a single catalyst bed. The catalytic reaction itself is stopped between each regeneration cycle by stopping the flow of one or more reactants. When applied to the alkylation of aromatics using olefins, the process comprises (1) a reaction cycle in which both the olefin stream and the aromatic component stream are passed to the catalyst zone to effect the alkylation; (2) And a flash cycle in which only the desorbent stream is passed through the catalyst region. Alkylation of aromatic components using alkylating agents, C _Four ~ C ₆ C using a range of alkanes _Three ~ C ₆ It is disclosed that this type of process can be applied to alkylation of olefins, olefin hydrogenation, ether formation by reaction of olefins with alcohols, and ester formation by reaction of organic acids with alcohols.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Olefin polymerization carried out on a fixed bed of catalyst usually involves catalyst deactivation, which is known as a decrease in catalyst activity over time. In addition, catalyst deactivation may be accompanied by a large pressure drop in the fixed bed of the catalyst. All such deactivations or large pressure drops are counterproductive in this process and in some cases the deactivated catalyst may need to be regenerated or replaced. Unfortunately, both of these options have economic disadvantages. When the catalyst is regenerated, the deactivated catalyst bed must be discontinued during the regeneration process, usually by interrupting the accompanying processes that produce the olefinic feedstock or by removing the olefinic feedstock. To avoid disposal, a second “swing” catalyst bed must be available during the regeneration process. Even when replacing a deactivated catalyst, the catalyst bed cannot be manipulated during the replacement process, and for the same reason a second “swing” catalyst bed must be available during this replacement. Furthermore, there is a penalty that the cost of the replacement catalyst and the disposal cost of the deactivated catalyst are added by replacing the catalyst. In view of these penalties, regeneration or replacement of the catalyst is often much slower than efficient process operation without regeneration or replacement.
[0012]
The present applicant has discovered a method for regenerating a fixed bed of an olefin polymerization catalyst that can be carried out without stopping the operation of the catalyst bed. Accordingly, Applicants have discovered a cost-effective method of a spare “swing” reactor. In addition, the Applicant has discovered a catalyst regeneration method that does not incur any significant penalty with respect to cost or process interruption. Thus, Applicant's process can be used to maintain high catalytic activity and to operate the olefin polymerization apparatus efficiently.
[0013]
One aspect of the present invention is a process for the polymerization of olefins using a fixed bed of a solid acid catalyst comprising:
(A) contacting the first olefin-containing feedstock with the solid acid catalyst fixed bed under olefin polymerization conditions by passing the first feedstock through the fixed bed, removing the product stream from the fixed bed; The molar ratio of olefins to aromatics in one feedstock is at least about 12, whereby the acid catalyst is deactivated over time;
(B) after the acid catalyst is partially deactivated, a second olefin-containing feedstock is used instead of the first feedstock, wherein the second feedstock contains an aromatic compound, and the second feedstock The molar ratio of olefins to aromatics in the feedstock is from about 1 to about 10;
(C) contacting the second feedstock with the solid acid catalyst fixed bed under olefin polymerization conditions by passing the second feedstock through the fixed bed and removing the product stream from the fixed bed;
(D) passing the second feedstock through the fixed bed for a time effective to produce a regenerated acid catalyst that is highly active relative to the beginning of step (b) and removing the product stream from the fixed bed;
It relates to the process, including each stage.
[0014]
Another aspect of the present invention is a continuous process for the catalytic polymerization of olefins using a fixed bed of solid acid catalyst comprising alternately performing a first polymerization cycle and a second polymerization cycle comprising:
(A) The first polymerization cycle is
(I) passing a first olefin-containing feed through the catalyst bed, wherein the molar ratio of olefins to aromatics in the first feed is at least about 12;
(Ii) polymerizing at least a portion of the olefin content of the first feedstock in the catalyst bed under olefin polymerization conditions, thereby deactivating the catalyst over time;
(Iii) removing the product stream composed of the olefin polymer from the catalyst bed; and
(B) The second polymerization cycle is
(I) A second olefin-containing feedstock is used in place of the first feedstock, the second feedstock comprising an aromatic compound, and the olefins versus aromatics in the second feedstock The molar ratio of from about 1 to about 10;
(Ii) converting at least a portion of the olefin content of the second feedstock into a reaction product composed of an olefin polymer and an alkylated aromatic compound in the catalyst bed under olefin polymerization conditions;
(Iii) removing the product stream from the catalyst bed;
(Iv) continuing the second polymerization cycle for a time effective to produce a highly regenerated acid catalyst relative to the beginning of the second polymerization cycle;
Consists of.
[0015]
It is an object of the present invention to provide an improved polymerization process for olefins on a fixed bed of solid acid catalyst.
[0016]
It is an object of the present invention to provide a method for regenerating a fixed bed of an olefin polymerization catalyst which can be carried out simultaneously while using the catalyst to catalyze the polymerization of olefins.
[0017]
It is an object of the present invention to provide a process for the polymerization of olefins on a fixed bed of solid acid catalyst in a reactor that can retain high catalytic activity over a long period of time without having to shut down the reactor while regenerating or replacing the catalyst. That is.
[0018]
Another object of the present invention is to provide a method for periodically regenerating a fixed bed of an olefin polymerization catalyst that does not significantly interfere with the normal use of the fixed bed to catalyze olefin polymerization.
[0019]
Another object of the present invention is to provide an improved method for retaining high catalytic activity in a process that uses a fixed bed of solid phosphoric acid catalyst to catalyze the conversion of low molecular weight olefins to oligomers.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a process for polymerizing olefins on a fixed bed of a solid acid catalyst and to a method that can be used to regenerate or maintain the activity of the catalyst without stopping the use of the fixed bed to catalyze olefin polymerization. . The process of the present invention involves the use of two olefin-containing feeds referred to herein as first and second olefin-containing feeds or as first and second feeds. The first feedstock is a conventional olefin-containing feedstock that contains little, if any, aromatic compounds and gradually loses catalyst due to the formation of by-products that accumulate on the surface of the catalyst and in the catalyst pores. Live. In contrast, the second feedstock contains a significant concentration of aromatic compounds and has the ability to regenerate the deactivated catalyst. In the practice of the present invention, whenever the catalyst regeneration is deemed appropriate, the first feedstock is replaced with the second feedstock and the second feedstock is catalyzed for a time effective to at least partially regenerate the catalyst. Continue to flow to the floor. In a preferred embodiment, a second feedstock is used periodically instead of the first feedstock to maintain high catalytic activity.
[0021]
The olefin conversion process of the present invention comprises cyclic olefins, substituted cyclic olefins, and formula I, wherein R ₁ Is a hydrocarbyl group and R ₂ Are independently selected from the group consisting of hydrogen and hydrocarbyl groups). Preferably R ₁ Is an alkyl group and R ₂ Are each independently selected from the group consisting of hydrogen and alkyl groups.
[0022]
[Chemical 1]

[0023]
Examples of suitable cyclic olefins and substituted cyclic olefins include cyclopentene, 1-methylcyclopentene and cyclohexene. Examples of suitable olefins of the type of formula I include propene, 2-methylpropene, 1-butene, 2-butene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2 -Butene, 2,3-dimethyl-1-butene, 3,3-dimethyl-1-butene, 2,3-dimethyl-2-butene, 2-ethyl-1-butene, 1-pentene, 2-pentene, 2 -Methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 2-hexene and 3-hexene.
[0024]
Preferred olefins for use in carrying out the olefin conversion process of the present invention contain 3 to 6 carbon atoms, and highly preferred olefins contain 3 or 4 carbon atoms. If desired, the first and second olefin-containing feeds for the olefin conversion process of the present invention may comprise a mixture of different olefins. Alternatively, either or both of the first and second feedstocks may be composed of a single type of olefin. It is believed that the first and second feedstocks may contain materials other than olefins, such as diluents that are substantially inert under the reaction conditions used in the polymerization process. For example, either or both of the first and second feedstocks may contain substantial amounts of saturated hydrocarbons such as linear paraffins that are relatively non-reactive under the conditions of the olefin conversion process of the present invention. Can be included. Indeed, linear paraffins (eg, propane or butane) can be used as diluents and as recycle materials used in treating the heat generated by the exothermic olefin conversion reaction.
[0025]
The first olefin-containing feed is a conventional feed for olefin polymerization processes that contains little, if any, aromatic compounds. In one aspect of the invention, the first olefin-containing feed is substantially free of aromatic compounds. However, if desired, the first olefin-containing feedstock can include a small amount of one or more aromatic compounds. If aromatic components are present, alkylation of these components with olefins or olefins of the first olefin-containing feedstock can be carried out simultaneously with olefin polymerization. Desirably, the molar ratio of olefins to aromatics in the first olefin-containing feedstock is at least about 12, preferably at least about 15, and more preferably at least about 18. In such embodiments, volatile low molecular weight aromatic compounds (eg, benzene) that are inconvenient as gasoline components due to toxicity can be converted to low volatility materials that are highly desirable gasoline components by alkylation. For example, benzene and toluene can be converted to cumene and cymene, respectively, by monoalkylation with propene. Hybridization of olefin polymerization and aromatic alkylation is a particularly desirable process for use in the production of gasoline blend stocks. In such embodiments, low molecular weight olefins containing 3 or 4 carbon atoms can be used to alkylate benzene and convert excess olefins to oligomers. These products are all high octane and are desirable gasoline components.
[0026]
Aromatic compounds that can be incorporated into the first olefin-containing feedstock are all organic compounds having 6 to 20 carbon atoms that can be alkylated with olefins in the presence of an acid catalyst and contain aromatic functional groups. Is mentioned. Such materials include both aromatic compounds and substituted aromatic compounds having one or more substituents. Aromatic hydrocarbons having 6 to 10 carbon atoms and hydrocarbyl-substituted aromatic hydrocarbons are particularly preferred. Furthermore, mixtures of such materials can also be used as components of the first olefin-containing feedstock in the practice of the present invention. Examples of such materials include compounds of formula II containing 6 to 20 carbon atoms, wherein each R is independently selected from the group consisting of hydrogen and hydrocarbyl groups. However, preferred aromatic compounds are hydrocarbons containing 6 to 10 carbon atoms and are of the formula II wherein R is independently selected from the group consisting of hydrogen and alkyl of 1 to 3 carbon atoms. Compound). Benzene and toluene are particularly preferred.
[0027]
[Chemical formula 2]

[0028]
The aromatics contained in the first olefin-containing feed added to the olefin polymerization process of the present invention can be obtained from any desired source. However, when a gasoline blending feedstock is produced at an oil refinery by an olefin polymerization process, improved equipment and isolation equipment are convenient sources of aromatic components. For example, light reformate can be used, a typical material of this type having a total aromatic content of about 35% by volume and containing about 10% by volume benzene. C containing about 10% by volume of such light reformed oil and about 45% by volume of propylene and butylene mixed with propane and butanes. _Three ~ C _Four When producing the first olefin-containing feed by mixing about 90% by volume of the feed, about 80% of the benzene in the feed is alkylated in a conventional olefin polymerization apparatus using a solid phosphoric acid catalyst. Can be
[0029]
In the practice of this invention, a first olefin-containing feedstock typical of a polymerization apparatus for conversion to gasoline boiling range oligomers is propane, butane having an olefin concentration in the range of about 35% to about 60% by volume. , 1-methylpropane, propene, 1-butene, 2-butene and 1-methylpropene mixtures. However, the first olefin-containing feedstock can include, but is not limited to, other olefins or olefin mixtures, other various components including other diluents, and small amounts of aromatic compounds. . Furthermore, the olefin concentration can be used even if it is outside this range.
[0030]
The second olefin-containing feedstock used in the practice of the present invention includes a first concentration of aromatics that is significantly higher than any low concentration of aromatic compounds in the first feedstock. Different from the olefin-containing feedstock. Desirably, the molar ratio of olefins to aromatics in the second olefin-containing feedstock is from about 1 to about 10, preferably from about 2 to about 8, and more preferably from about 3 to about 8.
[0031]
The aromatic compounds that can be incorporated into the second olefin-containing feed are the same as those suitable for use in the first olefin-feed. As mentioned above, these aromatic compounds include all organic compounds having 6-20 carbon atoms that contain an aromatic functional group and can be alkylated with an olefin in the presence of an acid catalyst. Such materials include both aromatic compounds and substituted aromatic compounds having one or more substituents. Aromatic hydrocarbons and hydrocarbyl-substituted aromatic hydrocarbons containing 6 to 10 carbon atoms are particularly desirable. Preferred aromatic compounds for use as a component of the second olefin-containing feedstock are compounds of formula II wherein R is independently selected from the group consisting of hydrogen and alkyl of 1 to 3 carbon atoms. . Further preferred aromatic compounds are liquids having a boiling point in the range of about 20 ° C. to about 250 ° C. at atmospheric pressure. Benzene and toluene are particularly preferred.
[0032]
The aromatic compound contained in the second olefin-containing feedstock added to the olefin polymerization process of the present invention can be obtained from any desired source. However, as mentioned above, when a gasoline blend feedstock is produced in an oil refinery by an olefin polymerization process, catalytic crackers, refineries, and isolation devices are convenient sources of aromatic components. Light modified oils are a highly desirable source of suitable aromatic compounds, a typical material of this type having a total aromatic content of about 35% by volume and about 10% by volume of benzene.
[0033]
In one aspect of the invention, the second olefin-containing feedstock substantially comprises olefins boiling at atmospheric pressure in the range of about 20 ° C. to about 250 ° C. and comprising at least about 5% by volume aromatic components. The hydrocarbon fluid is comprised of about 20 to about 80 volume percent (this hydrocarbon fluid is referred to herein as a “substantially olefin-free hydrocarbon fluid”). For example, the second feedstock can be produced by replacing about 20 to about 80 volume percent of the first feedstock with a hydrocarbon fluid that is substantially free of olefins. Desirably, the substantially olefin-free hydrocarbon fluid boils in the range of about 20 ° C to about 250 ° C, with a preferred range of about 20 ° C to about 180 ° C, and a more preferred range of about 30 ° C to about 180 ° C. 130 ° C. The fluid further comprises at least about 5% by volume aromatics, preferably at least about 20% by volume aromatics, more preferably at least about 30% by volume aromatics. Typically, this fluid contains about 15 to about 85 volume percent aromatics. Finally, the substantially olefin-free hydrocarbon fluid has an olefin content of less than 5% by volume, preferably less than 3% by volume, more preferably less than 2% by volume.
[0034]
In refineries, naphtha, reformate and blends of aromatic and aliphatic hydrocarbons can be used as hydrocarbon fluids that are substantially free of olefins. However, modified oil is preferred. A typical light reformate suitable for use in the practice of the present invention comprises from about 0 to about 2% by volume of olefins, from about 20 to about 45% by volume of aromatic components, and 10% distillation point (T10). Is below about 160 ° F (71 ° C), 50% distillation (T50) is below 200 ° F (93 ° C), and 90% distillation point (T90) is below about 250 ° F (121 ° C). Has some distillation characteristics. These distillation points can be obtained by the ASTM D86-95 method (1996 Annual Book of ASTM Standards, Chapter 5, Petroleum Products, Lubricants, and Fossil Fuels) or can be found by conventional alternative methods. Understood. A typical light reformate contains about 5 to about 15 volume percent benzene.
[0035]
The aromatic component of the hydrocarbon fluid that is substantially free of olefins is very important, and those of the type described above are suitable for use as components of the second olefin-containing feedstock.
[0036]
The second olefin-containing feedstock of the present invention is produced by replacing a portion of the first olefin-containing feedstock with a hydrocarbon fluid that is substantially free of olefins, the fluid comprising the resulting mixture. It is used in an amount effective to ensure that the molar ratio of olefins to aromatics in the range is from about 1 to about 10.
[0037]
Any solid acidic material that can catalyze olefin polymerization can be used as a catalyst in the practice of the present invention, such as a liquid acid supported on a solid support. The solid acid catalyst desirably also has the ability to catalyze the alkylation of aromatic compounds with olefins. In practice, most solid acid materials that can catalyze the olefin polymerization process have this capability. In carrying out the olefin polymerization process of the present invention, the olefin-containing feedstock can be easily passed over the fixed bed of solid acid catalyst at a suitable temperature and pressure.
[0038]
Catalysts suitable for use in the practice of the present invention can be composed of materials such as acidic polymer resins, supported acids, and acidic inorganic oxides. Examples of suitable acidic polymer resins include polymeric sulfonic acid resins known and commercially available to those skilled in the art. Amberlyst® 35 (Rohm and Haas) is a typical example of such a material.
[0039]
Supported acids useful as catalysts include Bronsted acids (eg, phosphoric acid, sulfuric acid, boric acid, HF, fluorosulfonic acid) supported on a solid (eg, silica, alumina, silica-alumina, zirconium oxide or clay). , Trifluoromethanesulfonic acid, and dihydroxyfluoroboric acid) and Lewis acids (eg, BF _Three , BCl _Three AlCl _Three , AlBr _Three , FeCl ₂ , FeCl _Three ZnCl ₂ , SbF _Five , SbCl _Five And AlCl _Three And a combination of HCl and HCl), but is not limited thereto. When a liquid acid is used, the supported catalyst is usually prepared by mixing the desired liquid acid and the desired support and then drying.
[0040]
Acidic inorganic oxides useful as catalysts include alumina, silica-alumina, natural and synthetic pillar clays, and natural and synthetic zeolites (eg, faujasite; faujasites, mordenite, L, omega, X, Y, Beta, and ZSM), but are not limited to these. Very suitable zeolites include beta, Y, ZSM-3, ZSM-4, ZSM-5, ZSM-18 and ZSM-20. If desired, the zeolite can be included in an inorganic oxide matrix material (eg, silica-alumina).
[0041]
The catalyst can be a variety of materials such as Lewis acids (eg, BF _Three , BCl _Three And AlCl _Three ), Non-zeolitic solid inorganic oxides (eg, silica, alumina and silica-alumina), and large pore crystalline molecular sieves (eg, zeolite, pillar clay and aluminophosphate).
[0042]
Supported catalysts prepared by mixing phosphoric acid and support are often used in olefin polymerization processes and are highly preferred for use in the practice of the present invention. Such catalysts are referred to herein as solid phosphoric acid catalysts.
[0043]
The solid phosphoric acid catalyst is usually produced by mixing a phosphoric acid (eg, ortho-phosphoric acid, pyro-phosphoric acid or tetra-phosphoric acid) and a silicic acid-containing solid carrier to form a wet paste. The paste can be calcined and then crushed into catalyst particles, or the paste can be extruded or pelletized prior to calcination to produce more uniform catalyst particles. The carrier is usually a natural, porous silica-containing material (eg, diatomaceous earth, kaolin, dwarf earth or diatomaceous earth). Small amounts of various additives (eg, containing mineral talc, fuller's earth and iron compounds such as iron oxide) can be added to the support to increase its strength and hardness. The combination of support and additive usually constitutes about 15-30% by weight of the catalyst with the remainder being phosphoric acid. However, the amount of phosphoric acid used in the preparation of the catalyst can vary from about 8 to about 80% by weight of the catalyst. Solid phosphoric acid catalysts are commercially available and such materials are commercially available from UOP under the trade name SPA-2. This SPA-2 catalyst has the following properties: (1) nominal diameter 4.75 mm; (2) packing density 0.93 g / cm ^Three ; (3) P ₂ O _Five Calculated as: free phosphate content 16-20% by weight; and (4) P ₂ O _Five Is a cylindrical extrudate having a nominal total phosphoric acid content of 60% by weight. The preparation and properties of conventional solid phosphoric acid catalysts are described in US Pat. Nos. 2,120,702 (Ipatieeff et al.); 3,050,472 (Morell); 3,050,473 (Morell) and No. 3,132,109 (Morrell); and British Patent No. 863,539. These patents are included herein by reference.
[0044]
The olefin polymerization process of the present invention is carried out in a fixed bed of solid acid catalyst. If desired, the catalyst can be placed in a chamber reactor or a tubular reactor. In a tubular reactor, the catalyst is placed in a number of small tubes surrounded by circulating coolant. These tubes typically have an inner diameter of about 5 cm to about 15 cm, although other diameters can be used. Tubular reactors are often preferred over chamber reactors because reactor temperatures can be tightly controlled and can be easily manufactured for high pressure operation. Usually, multiple reactors are used. For example, an olefin polymerization apparatus that uses a tubular reactor can use as many as eight or more reactors. By using saturated hydrocarbons as quenches between many catalyst beds in the reactor and / or as recycling from the reactor effluent to the reactor feed, the heat generated by the exothermic olefin conversion reactor is reduced to the chamber reactor. Can be controlled within. The temperature in the tubular reactor is usually controlled by water or oil circulation around the reactor tube.
[0045]
In carrying out the olefin polymerization process of the present invention, to convert at least a portion of the olefins of the first feedstock into the desired product (eg, an oligomer useful as a gasoline blending feedstock or as a petrochemical feedstock). Effective temperature, pressure and time, the first olefin-containing feed is contacted with the solid acid catalyst. Desirably, the contact temperature is greater than about 50 ° C, preferably greater than 100 ° C, and more preferably greater than 125 ° C. Usually, the contacting is performed at a temperature in the range of about 50 ° C to about 350 ° C, preferably about 100 ° C to about 350 ° C, more preferably about 125 ° C to about 250 ° C. Of course, the optimum temperature is a function of the specific solid acid catalyst used and the specific olefins, their concentration in the first feedstock. However, for typical solid phosphoric acid catalysts used in combination with propylene and / or butylenes, the reaction temperature usually ranges from about 150 ° C to about 250 ° C.
[0046]
In the practice of the olefin polymerization process of the present invention, the first olefin-containing feed can be contacted with the solid acid catalyst at any suitable pressure. However, pressures in the range of about 0.01 to about 200 atmospheres are desirable, and air pressures in the range of about 1 to about 100 atmospheres are preferred. When typical solid phosphoric acid catalysts are used to convert propylenes and / or butylenes to gasoline blending feedstocks, the pressure is usually in the range of about 20 to about 90 atmospheres.
[0047]
In carrying out this process, a first olefin-containing feedstock is passed under olefin polymerization conditions by passing a first olefin-containing feedstock through the fixed bed and removing a product stream composed of the olefin polymer from the fixed bed. And a fixed bed of solid acid catalyst are brought into contact. This contact deactivates the acid catalyst over time.
[0048]
The above conditions of temperature and pressure suitable in the practice of the invention for converting at least a portion of the olefins in the first olefin-containing feedstock to olefin polymers are referred to herein as "olefin polymerization conditions". To do. These same olefin polymerization conditions are also used when contacting the second olefin-containing feedstock of the present invention with a fixed bed of catalyst. In particular, the feedstock is contacted with the solid acid catalyst fixed bed under olefin polymerization conditions by passing the second feedstock through the fixed bed and removing the product from the fixed bed. Contact with the second feedstock is continued for a time effective to produce a regenerated acid catalyst having high activity relative to the beginning of contact with the second feedstock.
[0049]
In one aspect of the invention, a substantially constant flow of feedstock is maintained in the fixed bed of the solid acid catalyst when replacing one feedstock with the other feedstock (ie, for any feedstock). Use the same flow rate). In another aspect of the invention, a substantially constant temperature and pressure is maintained in the fixed bed of the solid acid catalyst when one feedstock is replaced with the other feedstock (ie, for any feedstock). Use the same temperature and pressure).
[0050]
Most solid acid catalysts suitable for catalyzing the polymerization of olefins are also excellent catalysts for promoting the alkylation of aromatic compounds with olefins under the same or identical reaction conditions as the polymerization of olefins. Considering that the second olefin-containing feedstock contains aromatic compounds, alkylation of these aromatic compounds with olefins or olefins in the feedstock competes with olefin polymerization. As a result, olefin polymers and alkylated aromatics are obtained as products, the ratio of these products being a function of the molar ratio of olefins to aromatics in the second olefin-containing feedstock. For example, if the molar ratio of olefin to aromatic compound is 1, the formation of the product by alkylation of the aromatic compound is superior to the formation of the olefin polymerization product. However, when the molar ratio of olefins to aromatics is about 10, olefin polymer formation is usually predominant.
[0051]
As noted above, volatile low molecular weight aromatics (eg, benzene) that are undesirable as a gasoline component due to toxicity can be converted to less volatile materials that are highly desirable as a gasoline component by alkylation. Such a combination of polymerization and alkylation is particularly desirable when the product is used as a feedstock for a gasoline blend.
[0052]
In a preferred embodiment of the present invention, the first feed is the main feed of the process, and the first feed is periodically replaced with the second feed whenever a fixed bed of the catalyst needs to be regenerated. Perform a continuous process.
[0053]
It is believed that the catalyst deactivation that occurs during olefin polymerization in a fixed bed of catalyst using conventional olefin-containing feeds is mainly due to the formation of high-boiling polymers as by-products. These by-products remain in the catalyst and may be further converted to higher molecular weight polymers that resemble heavy tar and even have the appearance of a coke-like material. These substances cover the catalyst particles, block the catalyst pores and deactivate the catalyst. Occasionally, impurities may occur in the olefin-containing feed and deactivate the catalyst. Such impurities include, but are not limited to ethers (eg, dimethyl ether and methyl isopropyl ether). It is considered that these ethers may deactivate the catalyst when adsorbed on the catalyst.
[0054]
Due to its relatively high aromatic content, the second feedstock of the present invention is a better solvent than the first feedstock. Thus, the second feedstock, compared to the first feedstock, has the following points: (1) dissolves or elutes catalyst-derived tars and unfavorable polymers; and (2) all other adsorbed catalysts from the catalyst. It is considered more effective in removing poison. When the two feeds are contacted at a high temperature, for example, as used for olefin polymerization in the first feed on the catalyst, the second feed removes the deactivated material from the deactivated catalyst. Most effective.
[0055]
【Example】
C by conversion to dimer or trimer _Three And C _Four Conversion of olefins to raw materials for high octane gasoline blending was performed on a solid phosphoric acid catalyst (SPA-2, UOP) in a polymerization apparatus containing 8 tubular reactors (identified as reactors A-H). . However, one of the reactors (Reactor D) was at rest at the time of this experiment. A small amount of light reformate (usually about 10 to about 23% by volume) and olefin-containing C _Three ~ C _Four The usual feed to the equipment was produced by blending with the stream. When the polymerization apparatus was operated for a long time using normal feedstock, the catalyst was significantly deactivated.
[0056]
A large amount of light reformate and olefin-containing C _Three ~ C _Four A recycled feedstock was produced by blending with the stream, and this recycled feedstock was replaced with normal feedstock for 8 hours. At the end of the 8 hour regeneration period, the polymerization apparatus was restarted using normal feedstock. Table I shows the operating conditions of the polymerization apparatus using a normal feedstock measured 7 hours before the start of use of the regenerated feedstock and 9 hours after the end of use of the regenerated feedstock. Olefin-containing C 7 hours before regeneration period, during regeneration period, and 9 hours after regeneration period _Three ~ C _Four The compositions of the stream and light reformate are shown in Tables II and III, respectively. These compositions represent the olefin-containing C used in the polymerizer for a considerable time before the catalyst regeneration period and during catalyst deactivation. _Three ~ C _Four Typical for stream and light reformate.
[0057]
Over the 8 hour regeneration period, the amount of light reformate charged to the polymerization equipment varied between 900 and 3800 bpd (143,100 to 604,100 liters / day), with an average of 2765 bpd (439,600 liters / day). Met. C charged into the polymerization apparatus during the same regeneration period _Three ~ C _Four The flow rate varied from 2519 to 6459 bpd (400,500 to 1,026,900 liters / day) and the average was 3699 bpd (588,100 liters / day). Thus, over the 8 hour regeneration period, the regenerated feed comprises about 43% by weight light reformate, about 13.9% by volume aromatics and C _Three ~ C _Four It contained about 22.7% by volume of olefins. The fluctuation of the light reforming oil flow rate during the regeneration test as described above is due to restrictions on the surge drum and pumping water.
[0058]
During the regeneration period, a temperature of 186 ° C. to 196 ° C. found when the polymerization apparatus is operated using ordinary feeds slightly before and after the regeneration period due to conversion of olefins in the regeneration feed. In contrast, sufficient heat of reaction was obtained to maintain the internal temperature of the reactor at 186 ° C. to 188 ° C. with essentially no change. The external temperature of the reactor during the regeneration period was substantially the same as the temperature before and after the regeneration period. The average internal pressure during the regeneration period was 80.8 atm gauge.
[0059]
The catalyst activity in the reactor of the polymerization apparatus was measured (1) 7 hours before the start of use of the regenerated feed and (2) 9 hours after the use of the regenerated feed. These activity values are shown in Table IV, which is the C of the reactor in question. _Three And C _Four It was calculated from the apparent rate constant of the conversion of olefins. The apparent rate constants were based on data obtained from gas chromatographic analysis of the reactor feed and effluent. The data in Table IV showed that the regeneration activity increased the catalytic activity in 6 out of 7 reactors. The activity is significantly improved on average, ranging from 10.6% in reactor A to 70.0% in reactor E.
[0060]
[Table 1]

[0061]
[Table 2]

[0062]
[Table 3]

[0063]
[Table 4]

Claims (20)

A process for the polymerization of olefins using a fixed bed of solid acid catalyst comprising:
(A) contacting the first olefin-containing feedstock with the solid acid catalyst fixed bed under olefin polymerization conditions by passing the first feedstock through the fixed bed, removing the product stream from the fixed bed; The molar ratio of olefins to aromatics in one feedstock is at least about 12, whereby the acid catalyst is deactivated over time;
(B) after the acid catalyst is partially deactivated, a second olefin-containing feedstock is used instead of the first feedstock, wherein the second feedstock contains an aromatic compound, and the second feedstock The molar ratio of olefins to aromatics in the feedstock is from about 1 to about 10;
(C) contacting the second feedstock with the solid acid catalyst fixed bed under olefin polymerization conditions by passing the second feedstock through the fixed bed and removing the product stream from the fixed bed; then (d) Passing the second feedstock through the fixed bed for a time effective to produce a regenerated acid catalyst that is highly active relative to the beginning of step (b) and removing the product stream from the fixed bed;
The process including each stage. The process of claim 1, wherein the molar ratio of olefins to aromatic hydrocarbons in the first feedstock is at least about 15. The process of claim 1, wherein the molar ratio of olefins to aromatic hydrocarbons in the second feedstock is from about 3 to about 8. The process of claim 1, wherein the process is a continuous process and steps (a)-(d) are repeated periodically. A continuous process for the catalytic polymerization of olefins using a fixed bed of solid acid catalyst comprising alternately performing a first polymerization cycle and a second polymerization cycle comprising:
(A) The first polymerization cycle is
(I) passing a first olefin-containing feed through the catalyst bed, wherein the molar ratio of olefins to aromatics in the first feed is at least about 12;
(Ii) polymerizing at least a portion of the olefin content of the first feedstock in the catalyst bed under olefin polymerization conditions, thereby deactivating the catalyst over time;
(Iii) removing the product stream composed of the olefin polymer from the catalyst bed; and (b) the second polymerization cycle comprises:
(I) A second olefin-containing feedstock is used in place of the first feedstock, the second feedstock comprising an aromatic compound, and the olefins versus aromatics in the second feedstock The molar ratio of from about 1 to about 10;
(Ii) converting at least a portion of the olefin content of the second feedstock into a reaction product composed of an olefin polymer and an alkylated aromatic compound in the catalyst bed under olefin polymerization conditions;
(Iii) removing the product stream from the catalyst bed; then (iv) continuing the second polymerization cycle for a time effective to produce a regenerated acid catalyst that is highly active relative to the beginning of the second polymerization cycle;
The process consisting of: 6. The process of claim 5, wherein the first feedstock is composed of at least one olefin selected from the group consisting of olefins containing 3 to 6 carbon atoms. The process of claim 6 wherein the first feedstock is composed of at least one olefin selected from the group consisting of olefins containing 3 to 4 carbon atoms. 6. The process of claim 5, wherein the first feedstock is an aromatic hydrocarbon and the aromatic hydrocarbon contains 6 to 10 carbon atoms. 6. The process of claim 5, wherein the molar ratio of olefins to aromatics of the first feedstock is at least about 15. The process of claim 5, wherein the first feedstock is substantially free of aromatic compounds. 6. The process of claim 5, wherein the second feedstock olefin to aromatic molar ratio is from about 3 to about 8. 6. The process of claim 5, wherein the second feedstock aromatic compound contains 6 to 10 carbon atoms. The second feedstock is comprised of from about 20 to about 80 volume% of a substantially olefin-free hydrocarbon fluid boiling at atmospheric pressure in the range of about 20 ° C. to about 250 ° C., and at least about 5 volume% of fragrance 6. A process according to claim 5, comprising a group component. 14. The process of claim 13, wherein the substantially olefin-free hydrocarbon fluid is selected from the group consisting of naphtha, reformate, and blends of aromatic and aliphatic hydrocarbons. The process of claim 13, wherein the substantially olefin-free hydrocarbon fluid contains at least about 20% by volume aromatics. 14. The process of claim 13, wherein the substantially olefin-free hydrocarbon fluid is reformate. The process of claim 5, wherein the solid acid catalyst is a solid phosphoric acid catalyst. 6. The process of claim 5, wherein fluid flow is maintained substantially constant in a fixed bed during both the first and second polymerization cycles. 6. The process of claim 5, wherein a substantially constant temperature and pressure is maintained in the fixed bed during both the first and second polymerization cycles. 6. The process of claim 5, wherein the product from the process comprises a product boiling in the gasoline range.