JP3616849B2 - Treatment method of styrene resin waste - Google Patents

Description

のいずれかに示す構造を有する芳香族系化合物の臭素化物、又は脂環式炭化水素臭素化物であることにある。
【００１４】
【作用】
本発明は、スチレン系樹脂廃棄物を難燃剤の存在下で、加熱、液化、熱分解することにより芳香族炭化水素油を生成取得することを特徴としている。難燃剤を添加してスチレン系樹脂廃棄物を熱分解させることにより、スチレンモノマーが減少し、トルエン、エチルベンゼン、イソプロピルベンゼンを主成分とする芳香族炭化水素油を比較的高収率で得ることができる。その反応機構は充分に解明されていないが、スチレン系樹脂廃棄物の熱分解時に難燃剤が存在することにより、液相・気相で熱分解反応が制御されるものと考えられる。すなわち、スチレン系樹脂廃棄物を熱分解させると、Ｃ−Ｃ結合が切断されてスチレンモノマーを主成分とする芳香族炭化水素油が得られるが、難燃剤の存在により、スチレンモノマーのビニル基のＣ＝Ｃ結合が更に還元、切断、転化等されているものと考えられる。その結果、得られた芳香族炭化水素油の特性が大幅に改質され、その成分特性から溶剤及びガソリンの添加剤用途のほか、必要に応じて各成分に分離して化学品原料としても利用することができるなど、その利用価値を高めることができる。
【００１５】
また、本発明の処理方法によると１つの熱分解槽での熱分解によりスチレン系樹脂廃棄物を上記成分にまで分解することができるので、本発明の処理方法では複雑な装置は必要でなく設備費が安価になり、低価格で廃棄物を有効利用できる処理が可能となる。
【００１６】
また、スチレン系樹脂廃棄物を処理する場合に、上述のように難燃剤、特にプラスチック難燃剤を所定量添加して熱分解させてもよいが、前記プラスチック難燃剤は通常、難燃化スチレン系樹脂、例えば、難燃化発泡ポリスチレン成形品、難燃化ＡＢＳなどに含まれているため、難燃剤を含有しないスチレン系樹脂廃棄物に難燃剤を加えて、又は難燃剤の代わりにこれら難燃化スチレン系樹脂又は他の難燃化プラスチックを加えて熱分解させることによっても同様の効果が得られる。そのため、従来、最も廃棄物処理が困難であったこれら難燃化スチレン系樹脂を簡単に処理できるだけではなく、廃棄物である難燃化プラスチックがそれらに混入していても特に分別などすることなくそのまま使用することができ、非常に経済的である。なお、前記難燃剤として、特定の臭素化合物を用いることにより特に良好な制御性を得ることができる。
【００１７】
【実施例】
次に、本発明に係るスチレン系樹脂廃棄物の処理方法の実施例を図面に基づいて説明する。
【００１８】
図１は本発明に係るスチレン系樹脂廃棄物の処理方法を実施するための装置の１例を示した概略図である。同図に示すスチレン系樹脂廃棄物の処理装置１０は熱分解槽１２と、その熱分解槽１２にスチレン系樹脂廃棄物を供給する廃棄物供給装置１４と、その廃棄物供給装置１４に難燃剤を供給する難燃剤供給装置１６と、熱分解槽１２において発生した蒸気状生成物を液化するための冷却装置１８と、冷却装置１８によって液化された油状生成物を回収するための油化タンク２０とから構成されている。
【００１９】
熱分解槽１２は加熱手段２２を備えていて、加熱手段２２により槽１２内に投入されたスチレン系樹脂廃棄物及び難燃剤を加熱して液化し、更に熱分解するように構成されていて、加熱手段２２は槽１２内の温度を一定範囲内に制御できるように構成されている。この加熱手段２２はバーナー、電気、スチーム等のいかなる手段により加熱するように構成されていてもよく、特に限定されるものではない。また、熱分解槽１０の内部には攪拌翼２４が設けられているのが好ましく、この攪拌翼２４によって液化されたスチレン系樹脂廃棄物及び難燃剤がほぼ均一に混合し、且つその混合物２６がほぼ均一な温度になるように攪拌される。
【００２０】
また、熱分解槽１２にはスチレン系樹脂廃棄物を供給する廃棄物供給装置１４が１又は複数の開閉弁２８を介して配設されていて、更に、その廃棄物供給装置１４には難燃剤を供給する難燃剤供給装置１６が開閉弁３０を介して配設されている。廃棄物供給装置１４及び難燃剤供給装置１６はそれぞれスチレン系樹脂廃棄物及び難燃剤を貯留するホッパーとしての機能を有し、特に廃棄物供給装置１４はスチレン系樹脂廃棄物と難燃剤をそれぞれ一定量計量して熱分解槽１２に供給するように構成されている。また、廃棄物供給装置１４には投入されたスチレン系樹脂廃棄物や難燃剤を含む難燃化プラスチックを適当な大きさに粉砕するとともに、添加された難燃剤を混合するカッタなどの粉砕手段３２が設けられている。なお、この粉砕手段３２は、予め粉砕したスチレン系樹脂廃棄物などを廃棄物供給装置１４に投入する場合には、必要としない。更に、熱分解槽１２と廃棄物供給装置１４との間に介装されている開閉弁２８は熱分解槽１２を気密に密閉し得るように構成されていて、空気（酸素）を遮断した状態で熱分解が行われるよう構成されている。
【００２１】
更に、熱分解槽１２には、その熱分解槽１２において発生させられた蒸気状生成物を液化するための冷却装置１８と、その冷却装置１８によって液化された油状生成物を回収するための油化タンク２０とが設けられていて、これら冷却装置１８と油化タンク２０は移送管３４により接続されている。冷却装置１８は蒸気状生成物をその各成分ガスの凝縮温度以下に冷却するものであればいかなる構成の装置でもよく、特に限定されるものではない。また、油化タンク２０は蒸気状生成物が液化された油状生成物を蒸発させたり、酸化などによって変質させたりしないように構成されているのが好ましく、その構造などは特に限定されるものではない。
【００２２】
以上、本発明を実施するための処理装置の一例を詳述したが、本発明はかかる実施装置の構成に限定されるものではない。
【００２３】
すなわち、本発明は熱分解槽１２内で難燃剤の存在下でスチレン系樹脂廃棄物を熱分解できるように構成されていればよく、例えば、図２に示すように、熱分解槽１２に廃棄物供給装置１４と難燃剤供給装置１６とを別々に設け、切換え開閉弁３６によりスチレン系樹脂廃棄物と難燃剤がそれぞれ別々に熱分解槽１２内に供給されるように構成してもよい。かかる構成によれば、難燃剤の供給量を適宜制御して、回収される油状生成物の各種成分と収率を制御することができる。
【００２４】
また、熱分解槽１２にその槽１２内を窒素などの不活性ガスで置換する置換装置を設け、処理装置１０の作動開始時や、スチレン系樹脂廃棄物を熱分解槽１２内に供給した時に、その槽内の雰囲気を不活性ガスで置換するように構成してもよい。あるいは、廃棄物供給装置１４に不活性ガス置換装置を設け、不活性ガスで置換されたスチレン系樹脂廃棄物を熱分解槽１２に供給するように構成してもよい。
【００２５】
上述の処理装置１０において、まず、廃棄物供給装置１４に投入されたスチレン系樹脂廃棄物は粉砕手段３２によって適当な大きさに粉砕され、必要に応じて難燃剤供給装置１６から添加された難燃剤と混合されて貯留される。次に、開閉弁２８を適宜開閉させて粉砕されたスチレン系樹脂廃棄物と難燃剤との混合物を熱分解槽１２内に供給した後、熱分解槽１２内を密閉する。なお、難燃剤を含む難燃化プラスチックをスチレン系樹脂廃棄物とともに投入してもよく、この場合は難燃剤を添加する必要はない。
【００２６】
熱分解槽１０内に供給されたスチレン系樹脂廃棄物と難燃剤との混合物２６は、密閉された熱分解槽１２内で加熱されて液化し、更に熱分解されて蒸気状生成物が発生する。熱分解により発生させられた蒸気状生成物は冷却装置１８で冷却されて液化させられ、油状生成物が油化タンク２０に回収される。回収された油状生成物は、そのまま、あるいは必要に応じて分離精製されて再利用に供されるのである。
【００２７】
本発明でいうスチレン系樹脂とは、ポリスチレン、優位量のスチレンモノマーと劣位量のハロゲン又は置換基で置換された置換スチレンとの共重合体、又はスチレンモノマーに劣位量、好ましくは３０重量％（以下、単に％と略記する）以下、更に好ましくは２０％以下の他の単量体、例えばブタジエン等のジエン類、アクリル酸類、アクリル酸メチル、メチルメタアクリレート等のアクリル酸又はα−アルキルアクリル酸類、アクリル酸エステル類、α−アルキルアクリル酸エステル類、アクリルニトリル等を共重合した共重合体類（例、スチレン−ブタジエンゴム（ＳＢＲ）、ハイインパクトポリスチレン、ＡＢＳ系樹脂、メチルメタアクリレート−ブタジエン−スチレン系樹脂（ＭＢＳ）等）の廃棄物が良好に使用し得る。これらは単独でも混合でも使用できる。
【００２８】
なお、これらスチレン系樹脂（廃棄物）に難燃剤を後添加したもの、スチレン系樹脂の形成加工時に難燃剤が添加されたもの、すなわち難燃化スチレン系樹脂（廃棄物）、及びこれらの混合物などの廃棄物のいずれもが加熱液化の対象として使用できる。更には本発明の目的を損なわない範囲で前記スチレン系樹脂（廃棄物）に例えば３０％以下、好ましくは２０％以下の他の難燃化された又は難燃化されていない合成樹脂が混入した樹脂混合物（廃棄物）等であって広い概念のものをも含む。他の合成樹脂としては、例えばポリエチレン、ポリプロピレン等のオレフィン系樹脂、塩化ビニル系樹脂、ＰＥＴ等のポリエステル系樹脂、その他の一般に使用される合成樹脂（廃棄物）が例示される。
【００２９】
ここで、本発明に供されるスチレン系樹脂廃棄物は、フィルム、シート、成形品、塊等いかなる形状のものでもよく、発泡ポリスチレン成形品も好適に処理することができる。発泡ポリスチレン成形品を処理する場合は、常法にて脱泡あるいは減容した後、他の廃棄物と同様に粉砕して熱分解処理に供される。
【００３０】
また、本発明で使用する難燃剤は一般に添加形難燃剤と反応形難燃剤と呼ばれる２タイプの難燃剤に分類することができ、いずれもプラスチックの内部に配合することによりその配合物を難燃化する効果のある元素、例えばハロゲン、アンチモン、リンなどを含む化合物である。添加形難燃剤としては、例えば含ハロゲン−リン系化合物、含リン系化合物、臭素化合物、塩素化合物、酸化アンチモン、塩素化パラフィンなどが挙げられる。また、反応形難燃剤としては、塩素系のクロレンディック酸、その無水物（テトラクロロフタル酸無水物）など、臭素系のテトラブロモフタル酸無水物、テトラブロモビスフェノールＡなど、リン系のＦｙｒｏｌ ６ ，Ｖｉｒｃｏｌ ８２などを挙げることができる。
【００３１】
本発明では、これらあらゆる種類の難燃剤を利用することができるが、回収される芳香族炭化水素油の成分割合から、特には添加形難燃剤に分類される臭素化合物が好ましい。特には、臭素化合物が、例えばベンゼン、ビスフェノールＡ、ヒドロキシジフェニルプロパン、ビフェニール、ジフェニールエーテル等及びこれら誘導体である芳香族系化合物の臭素化物、脂環式炭化水素臭素化物であることが好ましく、更には化３
【化３】

に示す構造を有する難燃剤がより好ましい。
【００３２】
また、かかる難燃剤は、スチレン系樹脂廃棄物の量に対して０．０１重量％以上存在させることにより、スチレンモノマーの生成を減少させることができ、トルエン、エチルベンゼン、イソプロピルベンゼンを主成分とする芳香族炭化水素を得ることができる。難燃剤の添加により油状生成物の回収率は若干低下する傾向が見られるが、スチレンモノマーが激減していることより、利用性の高い成分の回収率は増加しており好ましい。特には前記難燃剤が０．１重量％以上存在することが好ましく、更には０．５重量％以上存在することが、不安定なスチレンモノマーの生成を減少させる点で好ましい。なお、上限は特に制限されるものではなく、難燃剤が多量に存在するほどスチレンモノマーの生成が減少する傾向にあり好ましいが、処理コストが高くなることと、スチレンモノマーの生成を大幅に減少させることができなくなるなどの観点から、難燃剤の添加量は１５重量％以下が好ましい。
【００３３】
なお、熱分解温度は２００℃〜５５０℃で行うのが好ましい。２００℃以下では熱分解反応が進行せず、５５０℃以上では炭化が進行して油状生成物の回収率が低下するといった不都合が起こるからである。特には油状生成物の回収率、分解反応速度の点から３００℃〜４５０℃で熱分解させるのがより好ましい。
【００３４】
このようにして得られた油状生成物は芳香族炭化水素油であり、その主成分はトルエン、エチルベンゼン、イソプロピルベンゼンである。すなわち、本発明の処理方法により、液相のみの熱分解でスチレンモノマーが減少してトルエン、エチルベンゼン、イソプロピルベンゼンが主成分となる芳香族炭化水素油を比較的高収率で得ることができる。得られた芳香族炭化水素油は溶剤及びガソリンの添加剤用途のほか、必要に応じ、各成分に分離して化学品原料として利用し得るものである。また、本発明の処理方法は、熱分解槽と冷却器のみの簡単な装置で実施することができ、安価な処理コストでの実施が可能である。
【００３５】
以上、本発明に係るスチレン系樹脂廃棄物の処理方法の実施例を説明したが、本発明はこれらの実施例のみに限定されるものではない。特に、上述の処理方法を実施するための装置は例示した装置に限定されるものではないのは言うまでもない。例えば、熱分解槽１２内の攪拌翼２４は必ずしも必要ではなく、また廃棄物供給装置１４や難燃剤供給装置１６についても固体のスチレン系樹脂廃棄物や難燃剤を供給する装置だけでなく、例えば予めスチレン系樹脂廃棄物や難燃剤を含む難燃化プラスチックを加熱溶融させておき、液体状で熱分解槽１２に供給するように構成することも可能である。その他、熱分解槽１２に温度や圧力などを検知するセンサや、混合物２６をサンプリングして成分分析をするための装置などを配設するなど、本発明はその趣旨を逸脱しない範囲内で当業者の知識に基づき、種々なる改良、変更、修正を加えた態様で実施しうるものである。
【００３６】
以下に実施例により本発明をより具体的に説明するが、本発明はこれら実施例によって限定されるものではない。
【００３７】
実施例 １
スチレン系樹脂廃棄物として電気化学工業株式会社製ポリスチレン（電化スチロールＧＰ１３０１）ペレット３００ｇを使用し、これに難燃剤ＦＧ−３０１０（帝人化成（株）製；エチレンジブロマイド−４，４’−イソプロピリデンビス（２，６−ジブロモフェノール）縮合物）化４
【化４】

をそれぞれ１．５ｇ（０．５重量％）、６ｇ（２重量％）、３０ｇ（１０重量％）添加混合してパイレックス（Ｒ）ガラス製１リットルセパラブルフラスコ中に入れ、１０℃／分の昇温速度で４００℃まで昇温して熱分解を行い、良好な油状生成物の回収がなされた。熱分解は、油状生成物の量をモニターしながら、転化率一定となるまでの時間この温度に維持して行った。
【００３８】
得られた油状生成物中の芳香族成分の分析は、ガスクロマトグラフ及びガスクロマトグラフ磁場型質量分析装置を用いて定量、定性分析を行ない、各成分の回収率を求め、その結果を表１に示した。
【００３９】
【表１】

【００４０】
実施例 ２
難燃剤ＦＧ−３０１０の代わりに難燃剤ＣＤ−７５Ｐ（グレイド レイクスケミカル社製；ヘキサブロモシクロドデカン（ＨＢＣＤ））化５
【化５】

を６ｇ（２重量％）添加した他は、実施例１と同様にして油状生成物を回収し、その内の芳香族成分の回収率を求めてその結果を表２に示した。
【００４１】
【表２】

【００４２】
実施例 ３
難燃剤ＦＧ−３０１０の代わりに難燃剤ＦＧ−３２００Ｔ（帝人化成（株）製；２，２’− ビス（４− アリルオキシ−３，５− ジブロモフェニル） プロパン）化６
【化６】

を６ｇ（２重量％）添加した他は、実施例１と同様にして油状生成物を回収し、その内の芳香族成分の回収率を求めてその結果を表２に示した。
【００４３】
参考例 １
難燃剤ＦＧ−３０１０の代わりに難燃剤塩素化パラフィン４０（東洋ソーダ製；Ｃ２５Ｈ４５Ｃｌ１７）を６ｇ（２重量％）添加した他は、実施例１と同様にして油状生成物を回収し、その内の芳香族成分の回収率を求めてその結果を表２に示した。
【００４４】
比較例 １
難燃剤を添加しない以外は、実施例１と同様にして油状生成物を回収し、その内の芳香族成分の回収率を求め、その結果をブランクとして表１、表２に示した。
【００４５】
実施例 ４
スチレン系樹脂廃棄物として発泡ポリスチレン容器を使用し、該発泡ポリスチレン容器を１２０℃のオーブン中に入れて脱泡し、得られた減容物を約３ｍｍに粉砕した。この粉砕物３００ｇに難燃剤ＦＧ−３０１０を６ｇ（２重量％）添加した他は、実施例１と同様にして油状生成物を回収した。得られた油状生成物について実施例１と同様の分析を行ない、その内の芳香族成分の回収率を求めたところ、実施例１とほぼ同様の結果が得られた。
【００４６】
表１、表２より、難燃剤を添加することによりスチレンモノマーが減少しトルエン、エチルベンゼン、イソプロピルベンゼンが増加していることがわかる。また、難燃剤としては、塩素化合物よりも臭素化合物を添加した場合の方がスチレンモノマーの減少率が大きく、臭素化合物の種類によっても各成分の回収率が異なることがわかる。また、難燃剤の添加量が多いほどスチレンモノマーの減少率が大きいことがわかる。なお、難燃剤の添加により油状生成物全体の回収率が若干低下する傾向にあるが、有効利用し得る成分の回収率が増加していることがわかる。また、かかる処理方法は発泡ポリスチレンにおいても同様の結果が得られることがわかる。
【００４７】
実施例 ５
スチレン系樹脂廃棄物として電気化学工業株式会社製ポリスチレン（電気スチロールＧＰ１３０１）ペレット２２５ｇと、ポリエチレン７５ｇの混合物を使用し、難燃剤ＦＧ−３０１０を６ｇ（２重量％）添加し、以下、実施例１と同様にして油状生成物を回収した。また、ブランクとして難燃剤を添加しない場合（比較例２）についても同様の実験を行って油状生成物を回収した。得られた油状生成物について実施例１と同様の分析を行ない、その内の芳香族成分のモル数を求め、その結果を表３に示した。
【００４８】
【表３】

【００４９】
この結果より、ポリエチレンを混合させても油状生成物の成分特性には影響しないことがわかる。
【００５０】
【発明の効果】
本発明のスチレン系樹脂廃棄物の処理方法により、熱分解によって得られる油状生成物の成分特性を簡単に改質することができる。すなわち、スチレン系樹脂廃棄物を難燃剤、特に特定の臭素化合物の存在下で熱分解させることにより、油状生成物中のスチレンモノマーの割合を減少させ、トルエン、エチルベンゼン、イソプロピルベンゼンの割合を増加させることができる。その結果、得られた油状生成物の利用性が高まり、本発明はプラスチック廃棄物の有効利用法を提供し得るものである。また、本発明の処理方法は液相のみの熱分解であり、単純で小規模な装置で実施することができ、処理コストをかなり低下させることができる。なお、スチレン系樹脂廃棄物にポリエチレンのような他の樹脂廃棄物が混在していても、得られる油状生成物の成分特性には影響せず、良好にスチレン系樹脂廃棄物の処理を行うことができる。
【００５１】
更に、本発明で用いる難燃剤は一般にスチレン系樹脂廃棄物に含まれていることが多く、既に難燃剤が廃棄物中に含まれていればスチレン系樹脂廃棄物を処理する際に、わざわざ難燃剤を添加しなくてもこれらの難燃化プラスチックを直接処理することにより油状生成物の成分特質を改質することができる。そのため、従来処理が困難であった難燃化プラスチックを簡単に処理できるとともに、廃棄物である該難燃化プラスチックを改質剤として使用することができ、更に経済的な廃棄物処理が可能となる。
【００５２】
すなわち、本発明のスチレン系樹脂廃棄物の処理方法は、スチレン系樹脂廃棄物から、安価で簡単に芳香族系溶剤、ガソリン添加剤など付加価値の高い芳香族炭化水素油を比較的高収率で取得することができる優れた処理方法である。
【図面の簡単な説明】
【図１】本発明に係るスチレン系樹脂廃棄物の処理方法を実施するための装置の１例を示した概略説明図である。
【図２】本発明に係るスチレン系樹脂廃棄物の処理方法を実施するための装置の他の実施例を示した概略説明図である。
【図３】従来のスチレン系樹脂廃棄物の処理方法を実施するための装置の１例を示した概略図である。
【符号の説明】
１０；処理装置
１２；熱分解槽
１４；廃棄物供給装置
１６；難燃剤供給装置
１８；冷却装置
２０；油化タンク
２２；加熱手段[0001]
[Industrial application fields]
The present invention relates to a method for treating styrenic resin waste, and more specifically, aromatic hydrocarbon oils with high added value, such as aromatic solvents and gasoline additives, from styrenic resin waste at low cost, in a simple and high yield. The present invention relates to a method for treating styrene resin waste that can be obtained.
[0002]
[Prior art]
Today, plastics have penetrated every field of daily life and are one of the indispensable materials for supporting advanced technology. However, with the increase in production volume, waste disposal has become a serious social problem. Yes. In order to solve this problem, various policies such as development of material recycling, thermal recycling, simple incineration, and landfill are being considered as waste plastic measures. In particular, in recent years, due to increasing global environmental problems, problems such as proper disposal of waste, effective use of energy, and recycling have been strongly called out. For example, as one of the reuses of waste plastics, waste can be converted into fuel to achieve the two purposes of achieving complete efficiency and energy recovery without causing pollution and complete combustion. Research and development of pyrolysis oil conversion technology for the purpose has been actively conducted.
[0003]
By the way, looking at the processing methods for thermoplastics such as polystyrene, polyethylene, polypropylene, and polyvinyl chloride plastics, which account for the majority of plastic production, it is sufficient for practical use except for re-pelletization and small-scale use as molding materials. Has not yet reached its full effect. Among them, polystyrene, particularly expanded polystyrene, is used in large quantities in fish boxes, packaging materials for home appliances, trays, and various food containers as an inexpensive material excellent in light weight, impact resistance, heat retention, and safety. For this reason, expanded polystyrene is designated as one of the 14 general waste items stipulated by the Recycling Law, and it is necessary to recycle materials and heat, but most of them are incinerated as waste. The current situation is. The reason is that it is known that when polystyrene is thermally decomposed in an appropriate temperature range, an oily product mainly composed of styrene monomer can be obtained with a recovery rate of about 70%. This is because it is easily polymerized by heat and has a problem in storage stability, and it is difficult to reuse the obtained oily product. Therefore, establishment and practical application of the early reuse technology of these polystyrene and expanded polystyrene is desired, and technical development regarding the effective utilization method of styrene resin waste is being carried out from both the material recycling and thermal recycling aspects.
[0004]
As a technology studied on the reuse of polystyrene, for example, the properties of oily products (recovered oil) obtained by pyrolysis oil conversion of polystyrene waste are modified, and high octane gasoline base and high addition from polystyrene waste Japanese Patent Laid-Open No. 2-29492 discloses a method of obtaining a valuable chemical raw material in a high yield. In this method, polystyrene waste is melted (dehalogenation step), the melt is heated and thermally decomposed in a liquid phase (thermal decomposition step), and the generated vapor product is catalytically converted in a zeolite packed bed. (Catalytic conversion step) to produce and acquire an aromatic hydrocarbon oil. In the case of expanded polystyrene, after defoaming by steam treatment or the like, a dehalogenation step, a thermal decomposition step, and a contact conversion step are similarly performed.
[0005]
In order to explain this method in more detail, a schematic diagram is shown in FIG. First, polystyrene waste is supplied from the raw material inlet 1 to the primary pyrolysis tank 2, heated and melted for dehalogenation, and then further heated to perform pyrolysis. Next, the vapor-like product generated by the pyrolysis is transferred to the secondary pyrolysis tank 4 filled with the zeolite catalyst by the transfer pipe 3 and is contact-converted. The vapor product obtained by catalytic conversion is led to a cooler through a transfer pipe 3 to be liquefied, and an oily product is recovered. The obtained oily product (recovered oil) is an aromatic hydrocarbon oil mainly composed of ethylbenzene, isopropylbenzene and the like. This recovered oil has a high utility value in the petrochemical industry, and can be separated into each component as required and used as a chemical raw material, and can also be effectively used as a high-octane gasoline base due to its component characteristics.
[0006]
[Problems to be solved by the invention]
However, in order to carry out the treatment method disclosed in JP-A-2-29492, in addition to the primary pyrolysis tank 2 that performs a dehalogenation step and a pyrolysis step as shown in FIG. Since the secondary pyrolysis tank 4 filled with the zeolite catalyst for carrying out the process is necessary, the equipment becomes complicated and large-scale equipment, and the equipment cost becomes expensive. Moreover, since the zeolite used as a catalyst in the catalytic conversion step needs to be periodically replaced, there is a problem that the maintenance cost becomes high. Equipment costs, maintenance costs, etc. become expensive in this way, so that a large amount of expanded polystyrene is collected for profitability. As a result, lightweight expanded polystyrene is transported from a remote location, further reducing processing costs. A vicious cycle of pushing up occurs. Therefore, the treatment method cannot be carried out at a low cost, and has a problem that it is not suitable for the production of a product that cannot be expected to be profitable, such as a solvent for recycling and commercialization.
[0007]
In addition, since it is inevitable that the recovered polystyrene waste is mixed with polystyrene molded products that are flame-retardant with bromine compounds, PVC plastics, etc., in the treatment of polystyrene waste, halogen groups such as chlorine and bromine There is a current situation that mixing of elements cannot be avoided. These halogen group elements are catalyst poisons of the zeolite catalyst, which easily poisons the zeolite catalyst and loses its catalytic activity, making it impossible to perform catalytic conversion. For this reason, in the dehalogenation step of melting before thermal decomposition, a means for removing these halogen group elements is taken, but it is possible to avoid that the halogen group element mixed in decreases the activity of the zeolite catalyst. In addition, there is also a problem that it is not suitable for waste disposal in which flame-retardant plastic is mixed.
[0008]
Accordingly, the present inventors have solved the above-mentioned problems, and have produced aromatic hydrocarbon oil with high utility value from styrene-based resin waste without being adversely affected by halogen group elements mixed in at a low price. As a result of intensive research to provide a method for treating styrene resin waste obtained in high yield, the present invention has been achieved.
[0009]
[Means for Solving the Problems]
The gist of the method for treating styrene resin waste according to the present invention is that a styrene resin waste to which a flame retardant is added and / or a styrene resin waste containing a flame retardant is heated in a pyrolysis tank. To liquefy and thermally decompose.
[0010]
The gist of the method for treating styrene resin waste according to the present invention is that a flame retardant comprising an organic bromide is added to styrene resin waste to obtain a flame retardant-containing styrene resin waste, the flame retardant By heat-containing styrene resin waste in a pyrolysis tank and liquefying and pyrolyzingGenerating a vaporous product, cooling and liquefying and collecting the vaporous product,The styrene-based resin waste is characterized in that it is an aromatic hydrocarbon oil having a low styrene monomer content as compared with the case where it is thermally decomposed without adding the flame retardant.
[0011]
In such a styrene resin waste treatment method, the flame retardant comprising the organic bromide is at least 0.01 wt% or more, preferably 0.1 wt% or more, more preferably, based on the styrene resin waste. Is added in an amount of 0.5 to 15% by weight.
[0012]
The flame retardant comprising the organic bromide is benzene, bisphenol A, hydroxydiphenylpropane, biphenyl,Diphenyl etherAnd a bromide of an aromatic compound which is a derivative thereof, or an alicyclic hydrocarbon bromide.
[0013]
In particular, theFlame retardant made of organic bromideHowever,
[Chemical 2]

Having a structure shown in any ofIt is a bromide of an aromatic compound or an alicyclic hydrocarbon bromide.There is.
[0014]
[Action]
The present invention is characterized in that an aromatic hydrocarbon oil is produced and obtained by heating, liquefying, and thermally decomposing a styrene resin waste in the presence of a flame retardant. By adding a flame retardant and thermally decomposing styrene resin waste, styrene monomer is reduced, and aromatic hydrocarbon oils mainly composed of toluene, ethylbenzene, and isopropylbenzene can be obtained in a relatively high yield. it can. Although the reaction mechanism has not been fully elucidated, it is considered that the thermal decomposition reaction is controlled in the liquid phase and the gas phase due to the presence of the flame retardant during the thermal decomposition of the styrene resin waste. That is, when the styrene resin waste is pyrolyzed, the C—C bond is cleaved to obtain an aromatic hydrocarbon oil mainly composed of a styrene monomer. However, due to the presence of the flame retardant, the vinyl group of the styrene monomer is It is considered that the C═C bond is further reduced, cleaved, converted and the like. As a result, the characteristics of the resulting aromatic hydrocarbon oil have been drastically improved. From the component characteristics, it can be used as a chemical raw material by separating it into components as needed, in addition to the use of additives for solvents and gasoline. The utility value can be increased.
[0015]
Further, according to the treatment method of the present invention, the styrene resin waste can be decomposed to the above components by thermal decomposition in one pyrolysis tank, so that the treatment method of the present invention does not require complicated equipment and equipment. Costs are reduced, and processing that can effectively use waste at a low price is possible.
[0016]
Further, when treating styrene resin waste, a flame retardant, particularly a plastic flame retardant, may be added and thermally decomposed as described above, but the plastic flame retardant is usually a flame retardant styrene series. Because it is contained in resins such as flame retardant foamed polystyrene molded products and flame retardant ABS, these flame retardants are added to styrene resin wastes that do not contain flame retardants, or instead of flame retardants. The same effect can be obtained by adding a styrene-based resin or other flame retardant plastic and causing thermal decomposition. Therefore, these flame retardant styrene resins, which have been the most difficult to dispose of in the past, can be easily treated, and even if waste flame retardant plastics are mixed in them, there is no particular separation. It can be used as it is and is very economical. Particularly good controllability can be obtained by using a specific bromine compound as the flame retardant.
[0017]
【Example】
Next, an example of a processing method of styrene resin waste concerning the present invention is described based on a drawing.
[0018]
FIG. 1 is a schematic view showing an example of an apparatus for carrying out the method for treating styrene resin waste according to the present invention. The styrene resin waste treatment apparatus 10 shown in FIG. 1 includes a thermal decomposition tank 12, a waste supply apparatus 14 for supplying styrene resin waste to the thermal decomposition tank 12, and a flame retardant for the waste supply apparatus 14. SupplyFlame retardant supply equipment16, a cooling device 18 for liquefying the vapor-like product generated in the thermal decomposition tank 12, and an oiling tank 20 for recovering the oily product liquefied by the cooling device 18.
[0019]
The thermal decomposition tank 12 is provided with a heating means 22, and is configured to heat and liquefy the styrene resin waste and the flame retardant charged into the tank 12 by the heating means 22, and further thermally decompose, The heating means 22 is configured so that the temperature in the tank 12 can be controlled within a certain range. The heating means 22 may be configured to be heated by any means such as a burner, electricity, steam, etc., and is not particularly limited. Further, it is preferable that a stirring blade 24 is provided inside the pyrolysis tank 10, and the styrene resin waste and the flame retardant liquefied by the stirring blade 24 are mixed almost uniformly, and the mixture 26 is formed. Agitation is performed so that the temperature is substantially uniform.
[0020]
The pyrolysis tank 12 is provided with a waste supply device 14 for supplying styrene resin waste via one or a plurality of on-off valves 28. The waste supply device 14 further includes a flame retardant. SupplyFlame retardant supply equipment16 is disposed via the on-off valve 30. Waste supply device 14 andFlame retardant supply equipment16 has a function as a hopper for storing styrene resin waste and a flame retardant, respectively. In particular, the waste supply device 14 measures a certain amount of styrene resin waste and a flame retardant and supplies them to the thermal decomposition tank 12. Is configured to do. In addition, the waste supply device 14 pulverizes the styrene resin waste and the flame retardant plastic containing the flame retardant into an appropriate size, and pulverizing means 32 such as a cutter for mixing the added flame retardant. Is provided. The pulverizing means 32 is not necessary when styrene-based resin waste or the like pulverized in advance is put into the waste supply apparatus 14. Furthermore, the on-off valve 28 interposed between the pyrolysis tank 12 and the waste supply device 14 is configured to be able to hermetically seal the pyrolysis tank 12, and shuts off air (oxygen). It is comprised so that thermal decomposition may be performed.
[0021]
Further, the pyrolysis tank 12 has a cooling device 18 for liquefying the vapor-like product generated in the pyrolysis tank 12 and an oil for recovering the oily product liquefied by the cooling device 18. The cooling device 18 and the oil tank 20 are connected by a transfer pipe 34. The cooling device 18 may be any device as long as it cools the vapor-like product below the condensation temperature of each component gas, and is not particularly limited. In addition, the oil tank 20 is preferably configured so as not to evaporate an oily product obtained by liquefying a vapor-like product or to change the quality by oxidation or the like, and the structure thereof is not particularly limited. Absent.
[0022]
As mentioned above, although an example of the processing apparatus for implementing this invention was explained in full detail, this invention is not limited to the structure of this implementation apparatus.
[0023]
That is, the present invention only needs to be configured so that the styrene resin waste can be pyrolyzed in the presence of the flame retardant in the pyrolysis tank 12. For example, as shown in FIG. The material supply device 14 and the flame retardant supply device 16 may be provided separately, and the styrenic resin waste and the flame retardant may be separately supplied into the thermal decomposition tank 12 by the switching on-off valve 36. According to such a configuration, it is possible to control the various components and yield of the recovered oily product by appropriately controlling the supply amount of the flame retardant.
[0024]
In addition, the pyrolysis tank 12 is provided with a replacement device that replaces the inside of the tank 12 with an inert gas such as nitrogen, and when the processing apparatus 10 starts operating or when styrene resin waste is supplied into the pyrolysis tank 12. The atmosphere in the tank may be replaced with an inert gas. Alternatively, an inert gas replacement device may be provided in the waste supply device 14 so that the styrene resin waste replaced with the inert gas is supplied to the thermal decomposition tank 12.
[0025]
In the processing apparatus 10 described above, first, the styrene-based resin waste charged into the waste supply apparatus 14 is pulverized to an appropriate size by the pulverizing means 32 and added from the flame retardant supply apparatus 16 as necessary. It is mixed with fuel and stored. Next, the mixture of the styrene resin waste and the flame retardant pulverized by appropriately opening and closing the on-off valve 28 is supplied into the thermal decomposition tank 12, and then the inside of the thermal decomposition tank 12 is sealed. In addition, you may throw in the flame-retardant plastics containing a flame retardant with a styrene resin waste, In this case, it is not necessary to add a flame retardant.
[0026]
The mixture 26 of the styrene resin waste and the flame retardant supplied into the pyrolysis tank 10 is heated and liquefied in the sealed pyrolysis tank 12 and further pyrolyzed to generate a vapor product. . The vapor-like product generated by the thermal decomposition is cooled and liquefied by the cooling device 18, and the oily product is collected in the oiling tank 20. The recovered oily product is reused as it is or after being separated and purified as necessary.
[0027]
The styrenic resin referred to in the present invention is polystyrene, a copolymer of a dominant amount of styrene monomer and a substituted styrene substituted with a subordinate amount of halogen or a substituent, or a subordinate amount to the styrene monomer, preferably 30% by weight ( Hereinafter, it is simply abbreviated as%), more preferably 20% or less, other monomers such as dienes such as butadiene, acrylic acid, acrylic acid such as methyl acrylate, methyl methacrylate, or α-alkyl acrylic acid. , Copolymers obtained by copolymerization of acrylic esters, α-alkyl acrylic esters, acrylonitrile, etc. (eg, styrene-butadiene rubber (SBR), high impact polystyrene, ABS resin, methyl methacrylate-butadiene-) Waste of styrene resin (MBS) etc. can be used well. These can be used alone or in combination.
[0028]
In addition, those obtained by adding a flame retardant to these styrene resins (waste), those obtained by adding a flame retardant during the formation processing of styrene resins, that is, flame retardant styrene resins (waste), and mixtures thereof Any of the wastes such as can be used as a target for heat liquefaction. Furthermore, other flame retardant or non-flame retardant synthetic resins are mixed in the styrene resin (waste), for example, 30% or less, preferably 20% or less, as long as the object of the present invention is not impaired. It includes resin concepts (waste) and broad concepts. Examples of other synthetic resins include olefin resins such as polyethylene and polypropylene, vinyl chloride resins, polyester resins such as PET, and other commonly used synthetic resins (waste).
[0029]
Here, the styrenic resin waste provided for the present invention may have any shape such as a film, a sheet, a molded product, or a lump, and a foamed polystyrene molded product can be suitably processed. When processing an expanded polystyrene molded article, it is defoamed or reduced in volume by a conventional method, and then pulverized in the same manner as other wastes and subjected to thermal decomposition.
[0030]
The flame retardants used in the present invention can be generally classified into two types of flame retardants called additive flame retardants and reactive flame retardants, both of which are blended into the interior of the plastic to make the flame retardant flame retardant. It is a compound containing an element having an effect of converting to halogen, for example, halogen, antimony, phosphorus or the like. Examples of the additive-type flame retardant include halogen-containing phosphorus compounds, phosphorus-containing compounds, bromine compounds, chlorine compounds, antimony oxide, and chlorinated paraffin. Reactive flame retardants include chlorinated chlorendic acid, its anhydride (tetrachlorophthalic anhydride), brominated tetrabromophthalic anhydride, tetrabromobisphenol A, and phosphorus-based Fyrol. 6, Vircol 82 and the like.
[0031]
In the present invention, all kinds of flame retardants can be used, but bromine compounds classified as additive-type flame retardants are particularly preferable from the component ratio of the recovered aromatic hydrocarbon oil. In particular, it is preferable that the bromine compound is, for example, a brominated product of an aromatic compound, such as benzene, bisphenol A, hydroxydiphenylpropane, biphenyl, diphenyl ether, and the like, or an alicyclic hydrocarbon bromide thereof. Hakka 3
[Chemical 3]

A flame retardant having the structure shown in FIG.
[0032]
In addition, when the flame retardant is present in an amount of 0.01% by weight or more based on the amount of styrene resin waste, the production of styrene monomer can be reduced, and toluene, ethylbenzene, and isopropylbenzene are the main components. Aromatic hydrocarbons can be obtained. Although the recovery rate of the oily product tends to decrease slightly due to the addition of the flame retardant, the recovery rate of highly useful components has increased because the styrene monomer has been drastically reduced. In particular, the flame retardant is preferably present in an amount of 0.1% by weight or more, and more preferably 0.5% by weight or more from the viewpoint of reducing the formation of unstable styrene monomer. The upper limit is not particularly limited, and the more the flame retardant is present, the more preferable it is because the production of styrene monomer tends to decrease, but the processing cost is increased and the production of styrene monomer is greatly reduced. From the standpoint that it becomes impossible, the amount of the flame retardant added is preferably 15% by weight or less.
[0033]
The thermal decomposition temperature is preferably 200 ° C to 550 ° C. This is because the thermal decomposition reaction does not proceed at 200 ° C. or less, and carbonization proceeds at 550 ° C. or more, resulting in a disadvantage that the recovery rate of the oily product is lowered. In particular, it is more preferable to perform thermal decomposition at 300 to 450 ° C. from the viewpoint of the recovery rate of the oily product and the decomposition reaction rate.
[0034]
The oily product thus obtained is an aromatic hydrocarbon oil, the main components of which are toluene, ethylbenzene and isopropylbenzene. That is, according to the treatment method of the present invention, an aromatic hydrocarbon oil mainly composed of toluene, ethylbenzene, and isopropylbenzene can be obtained in a relatively high yield by reducing the styrene monomer by thermal decomposition of only the liquid phase. The obtained aromatic hydrocarbon oil can be used as a chemical raw material by being separated into various components as required in addition to the use of additives for solvents and gasoline. Further, the treatment method of the present invention can be carried out with a simple apparatus having only a pyrolysis tank and a cooler, and can be carried out at a low treatment cost.
[0035]
As mentioned above, although the Example of the processing method of the styrene resin waste concerning this invention was described, this invention is not limited only to these Examples. In particular, it goes without saying that an apparatus for carrying out the above-described processing method is not limited to the exemplified apparatus. For example, the stirring blade 24 in the pyrolysis tank 12 is not necessarily required, and the waste supply device 14 and the flame retardant supply device 16 are not only devices that supply solid styrene resin waste and flame retardant, It is also possible to heat and melt a flame retardant plastic containing a styrene resin waste or a flame retardant in advance and supply the liquid to the thermal decomposition tank 12 in a liquid state. In addition, a person skilled in the art within the scope of the present invention does not depart from the spirit of the present invention, such as a sensor for detecting temperature and pressure in the pyrolysis tank 12 and an apparatus for analyzing the component by sampling the mixture 26. Based on this knowledge, the present invention can be implemented with various improvements, changes, and modifications.
[0036]
The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.
[0037]
Example 1
300 g of polystyrene (Electrified polystyrene GP1301) pellets manufactured by Denki Kagaku Kogyo Co., Ltd. is used as the styrene resin waste, and flame retardant FG-3010 (manufactured by Teijin Chemicals Ltd.);Ethylene dibromide-4,4'-isopropylidenebis (2,6-dibromophenol) condensate4)
[Formula 4]

1.5 g (0.5 wt%), 6 g (2 wt%), and 30 g (10 wt%) were added and mixed in a 1 liter separable flask made of Pyrex (R) glass at 10 ° C./min. Thermal decomposition was performed by raising the temperature to 400 ° C. at a rate of temperature rise, and a good oily product was recovered. Thermal decomposition was carried out while maintaining the temperature for a period of time until the conversion rate was constant while monitoring the amount of oily product.
[0038]
Analysis of the aromatic component in the obtained oily product was performed by quantitative and qualitative analysis using a gas chromatograph and a gas chromatograph magnetic mass spectrometer, and the recovery rate of each component was determined. The results are shown in Table 1. It was.
[0039]
[Table 1]

[0040]
Example 2
In place of flame retardant FG-3010, flame retardant CD-75P (produced by Glade Lakes Chemical Co .; hexabromocyclododecane (HBCD)) 5
[Chemical formula 5]

The oily product was recovered in the same manner as in Example 1 except that 6 g (2% by weight) was added, and the recovery rate of the aromatic component was determined. The results are shown in Table 2.
[0041]
[Table 2]

[0042]
Example 3
Flame retardant FG-3200T (manufactured by Teijin Chemicals Ltd .; 2,2'-bis (4-allyloxy-3,5-dibromophenyl) propane) instead of flame retardant FG-3010
[Chemical 6]

The oily product was recovered in the same manner as in Example 1 except that 6 g (2% by weight) was added, and the recovery rate of the aromatic component was determined. The results are shown in Table 2.
[0043]
Reference example 1
An oily product was recovered in the same manner as in Example 1 except that 6 g (2% by weight) of chlorinated paraffin 40 (manufactured by Toyo Soda; C25H45Cl17) was added instead of flame retardant FG-3010. The recovery rate of the aromatic component was determined and the result is shown in Table 2.
[0044]
Comparative Example 1
The oily product was recovered in the same manner as in Example 1 except that no flame retardant was added, and the recovery rate of the aromatic component was determined. The results are shown in Tables 1 and 2 as blanks.
[0045]
Example 4
An expanded polystyrene container was used as the styrene-based resin waste. The expanded polystyrene container was placed in an oven at 120 ° C. to defoam, and the resulting reduced volume was pulverized to about 3 mm. An oily product was recovered in the same manner as in Example 1 except that 6 g (2% by weight) of the flame retardant FG-3010 was added to 300 g of this pulverized product. The obtained oily product was analyzed in the same manner as in Example 1, and the recovery rate of the aromatic component was determined. As a result, almost the same result as in Example 1 was obtained.
[0046]
From Tables 1 and 2, it can be seen that the addition of the flame retardant reduces the styrene monomer and increases toluene, ethylbenzene, and isopropylbenzene. Moreover, as a flame retardant, when the bromine compound is added rather than the chlorine compound, the reduction rate of the styrene monomer is large, and it can be seen that the recovery rate of each component varies depending on the type of the bromine compound. Moreover, it turns out that the decreasing rate of a styrene monomer is so large that there is much addition amount of a flame retardant. In addition, although the recovery rate of the whole oily product tends to be slightly lowered by the addition of the flame retardant, it can be seen that the recovery rates of components that can be effectively used are increasing. Moreover, it turns out that the same result is obtained also in this processing method also in expanded polystyrene.
[0047]
Example 5
As a styrene resin waste, a mixture of 225 g of polystyrene (electric polystyrene GP1301) pellets manufactured by Denki Kagaku Kogyo Co., Ltd. and 75 g of polyethylene was used, and 6 g (2% by weight) of a flame retardant FG-3010 was added. The oily product was recovered in the same manner as above. Moreover, the same experiment was performed also about the case where a flame retardant is not added as a blank (comparative example 2), and the oily product was collect | recovered. The obtained oily product was analyzed in the same manner as in Example 1, the number of moles of the aromatic component was determined, and the results are shown in Table 3.
[0048]
[Table 3]

[0049]
From this result, it can be seen that even when polyethylene is mixed, the component characteristics of the oily product are not affected.
[0050]
【The invention's effect】
The component characteristics of the oily product obtained by thermal decomposition can be easily modified by the method for treating styrene resin waste of the present invention. That is, by thermally decomposing styrenic resin waste in the presence of flame retardants, especially specific bromine compounds, the proportion of styrene monomer in the oily product is reduced and the proportion of toluene, ethylbenzene, isopropylbenzene is increased. be able to. As a result, the availability of the obtained oily product is enhanced, and the present invention can provide an effective utilization method of plastic waste. Further, the treatment method of the present invention is a thermal decomposition of only the liquid phase, and can be carried out with a simple and small-scale apparatus, and the treatment cost can be considerably reduced. Even if other resin wastes such as polyethylene are mixed in the styrene resin waste, the component characteristics of the resulting oily product are not affected, and the styrene resin waste should be treated well. Can do.
[0051]
Furthermore, in general, the flame retardant used in the present invention is often contained in styrene resin waste. If the flame retardant is already contained in the waste, it is difficult to treat the styrene resin waste. The component properties of the oily product can be modified by directly treating these flame retardant plastics without the addition of a flame retardant. Therefore, it is possible to easily process the flame retardant plastic, which has been difficult to process conventionally, and to use the flame retardant plastic, which is a waste, as a modifier. Become.
[0052]
That is, the styrene resin waste treatment method of the present invention is a relatively high yield of high-value-added aromatic hydrocarbon oils such as aromatic solvents and gasoline additives from styrene resin waste at low cost and easily. It is an excellent processing method that can be obtained by
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing an example of an apparatus for carrying out a method for treating styrene resin waste according to the present invention.
FIG. 2 is a schematic explanatory view showing another embodiment of an apparatus for carrying out the method for treating styrene resin waste according to the present invention.
FIG. 3 is a schematic view showing an example of an apparatus for carrying out a conventional method for treating styrene-based resin waste.
[Explanation of symbols]
10; Processing device
12: Pyrolysis tank
14: Waste supply equipment
16; Flame retardant supply device
18; Cooling device
20: Oil tank
22: Heating means

Claims (4)

A flame retardant composed of organic bromide is added to styrene resin waste to form a flame retardant-containing styrene resin waste, and the flame retardant-containing styrene resin waste is liquefied by heating in a thermal decomposition tank. When generating a vapor-like product by pyrolysis , and cooling the liquefied product to liquefy and recovering the styrene-based resin waste without adding the flame retardant A method for treating styrene-based resin waste, characterized in that an aromatic hydrocarbon oil having a low content of styrene monomer is used. The flame retardant comprising the organic bromide is added at least 0.01 wt% or more, preferably 0.1 wt% or more, more preferably 0.5 to 15 wt% with respect to the styrene resin waste. The processing method of the styrene-type resin waste of Claim 1 characterized by the above-mentioned. The flame retardant comprising the organic bromide is a bromide of an aromatic compound or alicyclic hydrocarbon bromide which is benzene, bisphenol A, hydroxydiphenylpropane, biphenyl, diphenyl ether and derivatives thereof. The processing method of the styrene resin waste as described in any one of Claims 1-3. A flame retardant comprising the organic bromide is

The method for treating styrene resin waste according to any one of claims 1 to 3, which is a brominated product of an aromatic compound having a structure shown in any of the above, or an alicyclic hydrocarbon bromide. .

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