JP4276748B2

JP4276748B2 - Residue removal method and equipment in plastic waste oil processing

Info

Publication number: JP4276748B2
Application number: JP25567599A
Authority: JP
Inventors: 省二児玉; 竜弘徳山; 勝英村田; 正信小林; 和男佐伯
Original assignee: ALTIS CO., LTD.
Current assignee: ALTIS CO., LTD.
Priority date: 1999-09-09
Filing date: 1999-09-09
Publication date: 2009-06-10
Anticipated expiration: 2019-09-09
Also published as: JP2001081474A

Description

【０００１】
【発明の属する技術分野】
本発明は、各種のプラスチックの廃棄物を熱分解により油化して再利用のために回収する油化処理における残査物を熱分解槽から取り出す方法及び装置に関する。
【０００２】
【従来の技術】
従来、プラスチック廃棄物の油化処理方法として、例えば熱分解槽で熱分解されて発生するガス状の熱分解生成物を、熱分解蒸気熱交換器で粗重質油成分と軽質油成分とに分離し、該軽質油成分を軽質油凝縮熱交換器で凝縮させて軽質油を取り出し、その一部を蒸気化して該熱分解槽に供給することにより該熱分解を進行させる方法が提案されている（特開平１０−１９５４５２号公報）。該熱分解槽には熱分解で発生する残査物が残るので、これを槽底から取り出して次の熱分解に備える必要がある。
【０００３】
【発明が解決しようとする課題】
該残査物は、プラスチック廃棄物に付着、含有されている金属成分、灰分や熱分解で生成するカーボン残査分などの有機物である。該金属成分は、アルミ片や鉄片、ステンレス片など比重の大きいもので、該灰分は、炭酸カルシウム、砂・石・ガラス片などの比重の大きい無機物であり、有機物にはカーボン残査分の他に溶融状態の未反応プラスチックがある。
【０００４】
該金属成分は、取り出し通路に設けられた開閉弁に咬み込まれ易く、開閉弁が完全に閉まらなくなると熱分解槽内の高温状態の熱分解油が外部へ漏れる原因になって好ましくない。炭酸カルシウム、砂・石・ガラス片などの灰分が熱分解油との固液混相状態にあって灰分の濃度が高いと、これの排出時の流速が速く差圧が大きいときにはブロッキングを起こし、残査物の排出通路が閉塞されてしまう不都合を生じる。また、有機物の残査は、比重が小さいため熱分解油中への沈降が遅く浮遊状態にあるため固液の分離を迅速に行えず、しかも常温で固まる性質があるから残査排出通路を閉塞してしまい、約１００℃以上で排出することが望まれる。溶融したプラスチック廃棄物を連続的に熱分解槽に投入して連続的に熱分解を行う場合や、熱分解槽に破砕した未溶融のプラスチック廃棄物を投入してバッチ式の熱分解を行う場合でも、この残査物の取り出しに伴う不都合がある。
【０００５】
本発明は、プラスチック廃棄物の油化処理で熱分解槽に残る残査物を迅速且つ円滑に排出し、熱分解槽内の熱分解油を外部へ漏らすことのない安全な残査物取出し方法と装置を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
本発明では、プラスチック廃棄物を熱分解槽で熱分解し、これにより発生するガス状の熱分解生成物を外部へ導出して分解油として回収し、該熱分解槽の槽底に溜まる残査物を開閉弁を備えた下方へ延びる排出管を介して該熱分解槽外へ排出する油化処理方法に於いて、該排出管の管端に残査受槽を接続しておき、その熱分解中に該開閉弁の上流側の排出管に外部から多少のスロップオイルを流し、その熱分解完了後に該開閉弁の下流側の排出管及び残査受槽にスロップオイルを充填してから該開閉弁を開き、次いで該開閉弁の上流側の排出管に供給するスロップオイル量を増やして該開閉弁を全開すると共に該残査受槽をスロップオイルタンクへ連通させて残査物を排出することにより、上記の目的を達成するようにした。該残査受槽を下部がコーン型の密閉容器で構成すると共に該排出管の管端を該残査受槽の底部へ延ばして接続し、該熱分解中に該開閉弁の上流側の排出管に外部から多少のスロップオイルを流す間は該残査受槽に不活性ガスを導入しておき、該熱分解完了後に該開閉弁の下流側の排出管及び残査受槽にスロップオイルを充填するときには該残査受槽の不活性ガスの一部を排出し、該残査受槽をスロップオイルタンクへ開いて残査物を排出するときには該残査受槽に不活性ガスを導入することにより、上記目的を一層適切に達成できる。また、本発明の方法は、請求項４乃至６に記載した構成の装置を使用することにより適切に実施できる。
【０００７】
【発明の実施の形態】
本発明の実施の形態を図面に基づき説明すると、図１はバッチ式のプラスチック廃棄物の油化処理装置の説明図で、同図の符号１は固形のプラスチック廃棄物を収容してこれを溶融すると共に熱分解する密閉された熱分解槽、２はプラスチック廃棄物の油化処理で生成した軽質油を貯蔵する軽質油タンク、３は該油化処理で生成した重質油を貯蔵する重質油タンクを示す。該熱分解槽１はその周壁に加熱流体が流通するジャケット４を備え、該ジャケット４及び槽内には該軽質油タンク２に予め用意した軽質油を熱交換器１４、２３により加熱して蒸気とし、更に加熱炉５で加熱して配管６から供給し、該ジャケット４からの熱と槽内に供給された軽質油の熱により投入されたプラスチック廃棄物を溶融し、脱塩化水素処理し、熱分解する。
【０００８】
該配管６からジャケット４に供給する軽質油の温度は、最初は加熱炉５により例えば２００℃以下に加熱され、槽内のプラスチック廃棄物が溶融した後にその温度を２００以上３２０℃以下程度の温度範囲とし、この溶融に伴い発生する塩素ガスを脱塩化水素槽７へ開閉バルブ２６を介して導いて脱塩化水素処理を行う。この処理でプラスチック廃棄物に含まれた塩素のうちの約９０％が除去される。これに続いて槽内へ例えば４７０℃の軽質油を供給して溶融したプラスチック廃棄物の熱分解処理を行い、発生するガス状の熱分解生成物をエジェクター８により強制的且つ迅速に槽内から引き出し、常圧蒸留塔９へ配管１０を介して供給する。脱塩されずに残った塩素は、塩酸として槽内に残り、炭化水素の塩素化をもたらすので、熱分解生成物の槽内に滞在する時間をエジェクター８の吸引により短縮し、その塩素化を生じにくくした。
【０００９】
該常圧蒸留塔９は公知のもので、熱媒ボイラー１１により例えば３５０℃に温度調整された熱媒体がリボイラー１２を循環し、これに供給された熱分解生成物を１７０℃程度でガス状態の熱分解生成物と液状態の熱分解生成物に分離する。該常圧蒸留塔９に発生するガス状態の熱分解生成物のみが配管１３を介して取り出され、該配管１３の途中に設けた熱交換器１４、塔頂液クーラー１５により最終的には約５０℃に冷却され、軽質油として凝縮されて軽質油タンク２に貯留される。これにより得られる軽質油は、常圧蒸留塔９により分離されたものであるから、いわゆる切れのよい軽質油で、２ｋｇ／ｃｍ²Ｇ程度の圧力でも３００℃で完全に蒸気とすることができる。この貯留された軽質油をポンプ１６により配管６に圧送し、その途中に設けた熱交換器１４、２３により蒸気化し、加熱炉５で例えば４７０℃に蒸気温度を上昇させて前記したジャケット４および槽内へプラスチック廃棄物の油化処理の熱源として供給される。この蒸気は該加熱炉５のチューブ５ａ内へ蒸気状態で通過し、その際昇温されるから、液からガス化するような相変化を伴わず、該チューブ５ａの表面が５００℃であってもコーク生成が殆どない。しかもこのチューブ５ａ内は圧力を高く設定することができるので、常圧の蒸気で加熱する場合に比べて該チューブ５ａの口径を例えば軽質油の流量が２０００ｋｇ／ｈのときに４０ｍｍに細くすることができ、油化装置全体の価格の２０〜３０％を占めるほどに高価な加熱炉５の価格を大幅に下げることができる。
【００１０】
また、該常圧蒸留塔９の塔底９ａに液状態で溜まる熱分解生成物は、２７３℃程度の重質油成分の塔底液で、ポンプ１７によりその一部は該エジェクター８の駆動液として配管１８に供給され、残りが該加熱炉５、フラッシャー１９、脱塩素反応器２０及びコンデンサー２１を設けた配管２２を介して重質油タンク３に貯留される。この塔底液は、蒸留により軽質油がほぼ完全に除かれた炭化水素油で、しかも脱塩素反応器２０で完全に脱塩することにより市販品の重油と差のない重質油が得られる。該加熱炉５の熱源には、軽質油タンク２の軽質油やその気化ガスを燃焼させて使用した。
【００１１】
該熱分解槽１に於いて熱分解に伴い発生する残査物は、槽底に設けたスクリューコンベア２４の押出し口２４ａから開閉弁２７を備えた下方へ延びる排出管２８を介して残査受槽２５へ排出される。該残査物は、前記したように、比重の大きいものではアルミ片や鉄片などの金属成分と炭酸カルシウム、砂・石・ガラス片などの無機物、及び比重の小さいカーボン残査分や未反応プラスチックなどの有機物であり、その熱分解の終了後で高温状態にあるこの残査物を、開閉弁２７の不作動を生じさせずまた排出管２８を詰まらせずに迅速且つ安全に排出するために、熱分解中にスロップオイル（このオイルの組成や性質について多少の説明が必要）を該開閉弁２７の上流側の排出管２８ａに多少流し、熱分解完了後に該開閉弁２７の下流側の排出管２８ｂ及び残査受槽２５にスロップオイルを充填してから該開閉弁２７を開き、次いで該開閉弁の上流側の排出管２７ａに供給するスロップオイル量を増やして該開閉弁２７を全開すると共に該残査受槽２５をスロップオイルタンク２９へ連通させて残査物を排出するようにした。
【００１２】
その詳細は図２に示す如くであり、該残査受槽２５は略コーン型の耐熱性の密閉容器で構成すると共に該排出管２８の管端を該残査受槽２５の底部へ延ばして接続し、該残査受槽２５の底部から第２開閉弁３０及び残査フィルター３１を介してスロップオイルタンク２９へ接続した。また、残査物の排出を制御するために下流側の排出管２８ｂには第３開閉弁３２を設けると共にこれら開閉弁２７と第３開閉弁３２の間からスロップオイルタンク２９へ、第４開閉弁３３を備えてスロップオイルタンク２９に連なる戻り管路３４及び流量制御弁３５を備えたスロップオイル供給管３６を設けた。該スロップオイル供給管３６にはポンプ３７によりスロップオイルタンク２９からスロップオイルを圧送するようにし、該供給管３６から分岐した分岐管３９に流量制御弁３８を設けて上流側の排出管２８ａへ流量制御されたスロップオイルが供給されるようにした。該分岐管３９は該開閉弁２７に接近した位置に開口させることが好ましい。該残査受槽２５の容積は、熱分解槽１の容積により異なるが、該熱分解槽１が１．５ｔのプラスチック廃棄物を処理するものである場合、約３００リットルに構成される。
【００１３】
密閉の該残査受槽２５の内部に残査物やスロップオイルを自在に供給し或いは排出するため、及び高温の残査物が酸化物になることを防止するため、該残査受槽２５の上方に窒素ガスなどの不活性ガスの導入口４０と排気口４１を設け、その給排を第５開閉弁４２及び流量制御弁４３で制御した。該排気口４１には該流量制御弁４３を備えた排気管４４を接続して該残査受槽２５よりも高い位置で排気されるようにした。
【００１４】
該熱分解槽１でのプラスチック廃棄物の熱分解に先立ち、該開閉弁２７及び第２開閉弁３０を閉じ、第３開閉弁３２を開いておき、第５開閉弁４２と流量制御弁４３を開いて下流側の排出管２８ｂと残査受槽２５に窒素ガスＡを充満させる。そして、熱分解槽１内でこれに投入されたプラスチック廃棄物が溶融状態になる頃を見計らって、スクリューコンベア２４を作動させ、スロップオイル供給管３６の流量制御弁３８をわずかに開いて少々のスロップオイルＢを上流側の排出管２８ａへ供給する。該スクリューコンベア２４の作動で熱分解槽１の槽底の狭隘部に残査物が集中して堆積することを防げ、該排出管２８ａにスロップオイルを流すことでその管内の残査物の流動性が保たれる。
【００１５】
該熱分解槽１内の熱分解が完了する頃合いを見計らって、更に流量制御弁３５を適度に開き、開閉弁３３を開く。そして図３に示すように、下流側の排出管２８ｂの内部にスロップオイルを充満させ、該残査受槽２５の内部に該排出管２８ｂの管端が浸る程度に充填しておく。熱分解が完了した時点では、比重の大きい金属成分や無機物が残査物の下方に溜まっており、その金属成分は弁に咬みこまれて弁の故障をもたらし、無機物は低温になると未分解プラスチックなどと共に固化して排出管２８や残査受槽２５の狭隘部を詰まらせてしまうが、本発明では、先ず流量制御弁３８により上流側の排出管２８ａに供給するスロップオイルの流量を例えば２ｍ³／ｈ程度に増やし、これにより比重の大きい金属成分などの固形物を該排出管２８ａ内のスロップオイル中で浮遊させ、第３開閉弁３２及び流量調整弁３５を開き、該流量制御弁３５を介して例えば１ｍ³／ｈのスロップオイルを下流側の排出管２８ｂへ導入し、第４開閉弁３３を閉じる。しばらくこのままにしておくと、溶融したプラスチックの未反応分中の下方に溜まる比重の大きい残査物がスロップオイルに混じって希釈状態になり流れがなくてもオイル中を沈下して残査受槽２５内へと排出される（図４）。比重の大きい残査物はその割合があまり大きくないので、排気管４４の流量制御弁４３は特に開く必要がない。
【００１６】
これにより、下方に溜まった金属成分や無機物が重力による沈降のみで静かに残査受槽２５へ排出され、開閉弁２７、３２に付着したり咬み込まれて閉弁に支障をきたしたり、途中で固化しにくくなるため排出管２８を詰まらせることがなくなる。また、該未反応成分などは高温であるため、そのまま排出すると熱ショックで各開閉弁や残査受槽２５が損傷するおそれがあるが、そこにスロップオイルが充填されているので熱ショックが緩和され、装置の損傷を防止できる。
【００１７】
こうした金属成分等の比重の大きい残査物を排出したのち、該排気管４４の流量制御弁４３を例えば５ｍ³／ｈの窒素ガス流量が得られる程に大きく開き、同時に分岐管３９の流量制御弁３８も例えば５ｍ³／ｈのスロップオイルが供給されるように大きく開くと、大量のスロップオイルが排出管２８内を流れ、この流れに伴われて浮遊状態のカーボン残査等の比重が小さい残査物を熱分解槽１から残査受槽２５へ抜き出すことができる（図５）。このスロップオイルの供給によって、熱分解槽１やスクリューコンベア２４内の高温の熱分解油を殆どそのままとしてカーボン残査等を抜き出せ、火災等の事故が生じない安全な液体として取り出せる。
【００１８】
残査物が殆ど取り出された後も、残査受槽２５に溢れない程度にスロップオイルの供給を続けることによって、開閉弁２７、３２が洗浄され、異物の介入のない状態で確実にこれらの開閉弁を閉弁できる（図６）。
【００１９】
このあと、第３開閉弁３２を開いたまま開閉弁２７、第４開閉弁３３、流量制御弁３５及び排気管４４の流量制御弁４３を閉じ、第２開閉弁３０及び第５開閉弁４２を開くと、下流側の排出管２８ｂへのスロップオイルの供給が断たれ、残査受槽２５内に窒素ガスが導入されるために残査物はそこに溜まったスロップオイルと共に残査フィルター３１へ排出され、スロップオイルが該フィルター３１を通過してスロップオイルタンク２９に回収されると共に固形の残査物が該フィルター３１で捕捉される（図７）。この間、分岐管３９の流量制御弁３８を調整して少量のスロップオイルを熱分解槽１へ流し、その内部の液体を十分に希釈することにより固化を防ぎ、次の熱分解に備える。
【００２０】
【実施例】
１５００ｋｇの破砕したプラスチック廃棄物を熱分解槽１に投入し、これと同時に熱媒ヒーター１１も作動させ、常圧蒸留塔９のリボイラー１２を発熱させて塔底液を約２８０℃に加熱し、ポンプ１７によりエジェクター８へ圧送した。開閉バルブ２６を閉じてエジェクター８が吸引作動を行わない運転状態とし、塔底油を塔底９ａにもどした。塔底油の循環により熱交換器２３が加熱状態になったところで軽質油タンク２に用意した軽質油をポンプ１６で圧送し、２７９℃の該熱交換器２３で蒸気化し、加熱炉５で３５０℃に昇温させてジャケット４へ供給し、２００℃でプラスチック廃棄物を溶融した。該プラスチック廃棄物の組成は、ポリエチレン５０ｗｔ％、ポリプロピレン１５ｗｔ％、ポリスチレン２５ｗｔ％、ポリ塩化ビニル１０ｗｔ％である。加熱炉５の運転条件は、圧力１．９ｋｇ／ｃｍ²Ｇ、軽質油流量２０００ｋｇ／ｈである。この溶融後昇温させ３００℃の熱分解槽１の槽内温度を３０分間維持し、溶融の初期に発生する塩素ガスを脱塩化水素槽７へ送り込んで脱塩化水素処理を行い、その処理の終えた３０分後に加熱炉５の温度を上げ、４１０℃の蒸気化した軽質油を槽内に供給し、溶融したプラスチック廃棄物の熱分解を行った。熱分解槽１内の熱分解生成物は、わずかな槽内の滞在時間でエジェクター４により蒸留塔９へ送られ、１７０℃程度で気化する軽質油成分の塔頂油は、熱交換器１４及び塔頂液クーラー１５で凝縮されて軽質油タンク２に貯留され、１７０℃で液状の重質油成分は塔底９ａに溜まり、ポンプ１７でエジェクター４と、加熱炉５、フラッシャー１９、脱塩素反応器２０、コンデンサー２１を介して重質油タンク３に重質油として貯留された。
【００２１】
熱分解時間は６時間で、その熱分解中には、スクリューコンベア２４を作動させると共に図２に示したように少量のスロップオイルを上流側の排出管２８ａに流し、窒素ガスを下流側の排出管２８ｂ及び残査受槽２５に充填して熱分解槽１の下方に溜まるカーボン等の残査物の固化を防止した。そして熱分解の終了後に、図３のように、下流側の排出管２８ｂの内部にスロップオイルを充填すると共に該排出管の端部が没する程度に残査受槽２５内にスロップオイルを充填した。このあと流量制御弁３８を調整して分岐管３９から２ｍ³／ｈにスロップオイル量を増大させ、残査物を浮遊状態としながら更に１ｍ³／ｈのスロップオイルを流量制御弁３５を介して導入し、開閉弁２７を開くことで比重の大きい鉄片や石などの残査物をスロップオイル中を沈下させて残査受槽２５に取り出した。そして開閉弁２７、３２を開けた状態で分岐管３９から流量制御弁３８を介して導入されるスロップオイルの量を５ｍ³／ｈに増大させ、排出管４４の流量制御弁４３も５ｍ³／ｈの流量に調整した。これにより比重の小さい残査物が残査受槽２５に排出され、この状態を１０分間維持して開閉弁２７、３２をスロップオイルで洗浄し、開閉弁２７、第４開閉弁３３及び流量制御弁３５、４３を閉じた。
【００２２】
次いで窒素ガスを導入しながら第２開閉弁３０を開き、該残査受槽２５に溜められた残査物及びスロップオイルを残査フィルター３１に取り出し、スロップオイルのみをスロップオイルタンク２９に回収した。スロップオイルで開閉弁２７と第３開閉弁３２を洗浄されているため、その閉弁を確実に行え、スロップオイルへの熱分解油の混入は殆ど無かった。
【００２３】
【発明の効果】
以上のように本発明によるときは、プラスチック廃棄物の熱分解に伴い熱分解槽内で発生する残査物を槽外へ排出する開閉弁を備えた排出管の管端に残査受槽を接続しておき、熱分解中に該開閉弁の上流側の排出管に多少のスロップオイルを流しておき、その熱分解完了後に該開閉弁の下流側の排出管及び残査受槽にスロップオイルを充填してから該開閉弁を開き、次いで該開閉弁の上流側の排出管に供給するスロップオイル量を増やして該開閉弁を全開すると共に該残査受槽をスロップオイルタンクへ連通させて残査物を排出するようにしたので、比重が大小に異なるものが混合したり、温度低下で固化して排出管や開閉弁を詰まらせ易く或いは開閉弁に食い込んで開閉作動の妨げとなるような固形物を含む残査物を確実且つ安全に排出することができ、熱分解槽の運転効率を高め得る等の効果があり、該残査受槽に不活性ガスを導入排出して残査物の排出を行うことで残査物が酸化しなくなって一層排出が容易になり、請求項４乃至６の装置構成とすることにより本発明の方法を適切に実施できる効果が得られる。
【図面の簡単な説明】
【図１】プラスチック廃棄物の熱分解の説明図
【図２】本発明の方法の実施に使用した残査物取出し装置の説明図
【図３】図２におけるスロップオイルの充填状態の説明図
【図４】比重の大きい残査物の抜き出し状態の説明図
【図５】比重の小さい残査物の抜き出し状態の説明図
【図６】残査物の抜き出し完了状態の説明図
【図７】スロップオイルと残査物の分離状態の説明図
【符号の説明】
１熱分解槽、２５残査受槽、２７開閉弁、２８排出管、２８ａ上流側の排出管、２８ｂ下流側の排出管、２９スロップオイルタンク、３０第２開閉弁、３１残査フィルター、３２第３開閉弁、３３第４開閉弁、３４戻り管路、３５・３８・４３流量制御弁、３６スロップオイル供給管、３９分岐管、４０不活性ガス導入口、４１排気口、４２第５開閉弁、４４排気管、[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for taking out residues from an oil decomposition process in which various plastic wastes are oiled by pyrolysis and recovered for reuse.
[0002]
[Prior art]
Conventionally, as a method for oily treatment of plastic waste, for example, gaseous pyrolysis products generated by pyrolysis in a pyrolysis tank are separated into crude heavy oil components and light oil components using a pyrolysis steam heat exchanger. The light oil component is condensed by a light oil condensing heat exchanger, the light oil is taken out, a part of the light oil is vaporized and supplied to the pyrolysis tank, and a method of proceeding the thermal decomposition is proposed. (Japanese Patent Laid-Open No. 10-195542). Since the residue generated by pyrolysis remains in the pyrolysis tank, it is necessary to remove it from the tank bottom and prepare for the next pyrolysis.
[0003]
[Problems to be solved by the invention]
The residue is an organic matter such as a metal component adhering to and contained in plastic waste, an ash content, or a carbon residue generated by thermal decomposition. The metal component is an aluminum piece, iron piece, stainless steel piece or the like with a high specific gravity, and the ash is an inorganic substance with a high specific gravity such as calcium carbonate, sand, stone, or glass piece. There are unreacted plastics in the molten state.
[0004]
The metal component is easily bitten by an on-off valve provided in the take-out passage, and if the on-off valve is not completely closed, high temperature pyrolysis oil in the pyrolysis tank is undesirably leaked to the outside. If the ash content of calcium carbonate, sand, stone, glass fragments, etc. is in a solid-liquid mixed phase with pyrolysis oil and the concentration of ash is high, blocking occurs when the flow rate during discharge is high and the differential pressure is large. There is a disadvantage that the discharge passage of the inspection object is blocked. In addition, the residue of organic matter has a low specific gravity, so it settles slowly in the pyrolysis oil and is in a floating state, so that solid-liquid separation cannot be performed quickly, and it has the property of solidifying at room temperature, so the residue discharge passage is blocked. Therefore, it is desired to discharge at about 100 ° C. or higher. When molten plastic waste is continuously put into a pyrolysis tank for continuous pyrolysis, or when unmelted plastic waste is crushed into a pyrolysis tank for batch pyrolysis However, there are inconveniences associated with the removal of this residue.
[0005]
The present invention provides a method for safely removing residue that quickly and smoothly discharges residue left in a pyrolysis tank by oily treatment of plastic waste and does not leak the pyrolysis oil in the pyrolysis tank to the outside. It is an object to provide a device.
[0006]
[Means for Solving the Problems]
In the present invention, the plastic waste is pyrolyzed in a pyrolysis tank, and the gaseous pyrolysis product generated thereby is extracted to the outside and recovered as cracked oil, and the residue accumulated at the bottom of the pyrolysis tank In the oiling treatment method of discharging an object out of the thermal decomposition tank through a downwardly extending discharge pipe provided with an opening / closing valve, a residue receiving tank is connected to the pipe end of the discharge pipe, and the thermal decomposition A small amount of slop oil is allowed to flow into the discharge pipe upstream of the on-off valve from the outside, and after the thermal decomposition is completed, the discharge pipe on the downstream side of the on-off valve and the residual tank are filled with slop oil, and then the on-off valve And then increasing the amount of slop oil supplied to the discharge pipe upstream of the on-off valve to fully open the on-off valve and communicating the residue receiving tank to the slop oil tank to discharge the residue, The above purpose was achieved. The bottom of the residue receiving tank is a cone-shaped sealed container, and the pipe end of the discharge pipe extends to the bottom of the residue receiving tank and is connected to the discharge pipe upstream of the on-off valve during the thermal decomposition. While flowing some slop oil from the outside, an inert gas is introduced into the residue receiving tank, and when the pyrolysis is completed, the discharge pipe on the downstream side of the on-off valve and the residue receiving tank are filled with the slop oil. A part of the inert gas in the residue receiving tank is discharged, and when the residue receiving tank is opened to the slop oil tank and the residue is discharged, the inert gas is introduced into the residue receiving tank to further increase the above object. Can be achieved appropriately. In addition, the method of the present invention can be appropriately carried out by using the apparatus having the configuration described in claims 4 to 6.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described. FIG. 1 is an explanatory view of a batch type plastic waste oil treatment apparatus. Reference numeral 1 in FIG. 1 contains solid plastic waste and melts it. 2 is a light oil tank for storing light oil produced by the oily treatment of plastic waste, and 3 is a heavy oil tank for storing heavy oil produced by the oily treatment. Indicates an oil tank. The pyrolysis tank 1 is provided with a jacket 4 through which a heating fluid circulates on the peripheral wall, and light oil prepared in advance in the light oil tank 2 is heated by the heat exchangers 14 and 23 in the jacket 4 and the tank. And heated in the heating furnace 5 and supplied from the pipe 6, the plastic waste introduced by the heat from the jacket 4 and the light oil supplied into the tank is melted, dehydrochlorinated, Thermally decomposes.
[0008]
The temperature of the light oil supplied from the pipe 6 to the jacket 4 is first heated to, for example, 200 ° C. or less by the heating furnace 5, and after the plastic waste in the tank is melted, the temperature is about 200 to 320 ° C. The dehydrochlorination treatment is conducted by introducing the chlorine gas generated along with the melting into the dehydrochlorination tank 7 through the open / close valve 26. This treatment removes about 90% of the chlorine contained in the plastic waste. Subsequently, for example, 470 ° C. light oil is supplied into the tank to thermally decompose the plastic waste that has been melted, and the gaseous pyrolysis product that is generated is forced and quickly discharged from the tank by the ejector 8. Draw out and supply to the atmospheric distillation column 9 via the pipe 10. Chlorine remaining without being desalted remains in the tank as hydrochloric acid, resulting in chlorination of hydrocarbons. Therefore, the time spent in the tank of the pyrolysis product is shortened by suction of the ejector 8, and the chlorination is reduced. It was hard to occur.
[0009]
The atmospheric distillation column 9 is a known one, and a heat medium whose temperature is adjusted to 350 ° C. by a heat medium boiler 11 circulates through the reboiler 12, and the pyrolysis product supplied thereto is gasified at about 170 ° C. The product is separated into a thermal decomposition product and a liquid thermal decomposition product. Only the thermal decomposition product in the gaseous state generated in the atmospheric distillation column 9 is taken out via a pipe 13 and finally is about about 30% by a heat exchanger 14 and a column top liquid cooler 15 provided in the middle of the pipe 13. It is cooled to 50 ° C., condensed as light oil, and stored in the light oil tank 2. Since the light oil thus obtained is separated by the atmospheric distillation column 9, it is a so-called light oil that can be completely vaporized at 300 ° C. even at a pressure of about ² kg / cm ² G. . The stored light oil is pumped to the pipe 6 by the pump 16, vaporized by the heat exchangers 14, 23 provided in the middle thereof, the steam temperature is raised to 470 ° C. in the heating furnace 5, for example, and the jacket 4 and It is supplied into the tank as a heat source for the plasticization of plastic waste. This steam passes in a steam state into the tube 5a of the heating furnace 5 and is heated at that time. Therefore, the surface of the tube 5a is 500 ° C. without causing a phase change that gasifies from the liquid. There is almost no coke formation. In addition, since the pressure in the tube 5a can be set high, the diameter of the tube 5a is reduced to, for example, 40 mm when the flow rate of light oil is 2000 kg / h, compared to the case where heating is performed with normal-pressure steam. The price of the heating furnace 5 that is so expensive that it accounts for 20 to 30% of the total price of the oil generator can be greatly reduced.
[0010]
The pyrolysis product that accumulates in the liquid state at the bottom 9 a of the atmospheric distillation column 9 is a heavy oil component bottom liquid at about 273 ° C., and a part of the driving liquid for the ejector 8 is supplied by the pump 17. And the remainder is stored in the heavy oil tank 3 through a pipe 22 provided with the heating furnace 5, flasher 19, dechlorination reactor 20 and condenser 21. This bottom liquid is a hydrocarbon oil from which light oil has been almost completely removed by distillation, and a heavy oil that is not different from commercially available heavy oil can be obtained by complete desalting in the dechlorination reactor 20. . As a heat source for the heating furnace 5, light oil in the light oil tank 2 and its vaporized gas were burned and used.
[0011]
Residue generated in the pyrolysis tank 1 due to pyrolysis is left as a residue receiving tank 28 through a discharge pipe 28 extending downward from an extrusion port 24a of a screw conveyor 24 provided at the bottom of the tank. To 25. As described above, the residue is a metal component such as an aluminum piece or an iron piece and an inorganic substance such as calcium carbonate, sand, stone, or glass piece, and a carbon residue or unreacted plastic having a low specific gravity. In order to quickly and safely discharge this residue, which is an organic substance such as the like, and is in a high temperature state after the thermal decomposition thereof, without causing the on-off valve 27 to be inoperative and without clogging the discharge pipe 28 During the pyrolysis, slop oil (necessary to explain the composition and properties of this oil) is allowed to flow to the discharge pipe 28a on the upstream side of the on-off valve 27 and discharged on the downstream side of the on-off valve 27 after completion of the pyrolysis. The on-off valve 27 is opened after filling the pipe 28b and the residue receiving tank 25 with slop oil, and then the on-off valve 27 is fully opened by increasing the amount of slop oil supplied to the discharge pipe 27a on the upstream side of the on-off valve. The residue 査受 tank 25 communicates to the slop oil tank 29 so as to discharge the remaining 査物.
[0012]
The details are as shown in FIG. 2, and the residue receiving tank 25 is formed of a substantially cone-shaped heat-resistant airtight container, and the pipe end of the discharge pipe 28 is extended to the bottom of the residue receiving tank 25 and connected. The residue tank 25 was connected to the slop oil tank 29 through the second on-off valve 30 and the residue filter 31 from the bottom. In order to control the discharge of the residue, the downstream discharge pipe 28b is provided with a third on-off valve 32 and a fourth on-off from the on-off valve 27 and the third on-off valve 32 to the slop oil tank 29. A return pipe 34 provided with a valve 33 and continuing to the slop oil tank 29 and a slop oil supply pipe 36 provided with a flow rate control valve 35 were provided. The slop oil supply pipe 36 is pumped to supply slop oil from the slop oil tank 29 by a pump 37, and a flow rate control valve 38 is provided in a branch pipe 39 branched from the supply pipe 36 so that the flow rate is supplied to the upstream discharge pipe 28a. A controlled slop oil was supplied. The branch pipe 39 is preferably opened at a position close to the on-off valve 27. The volume of the residue receiving tank 25 varies depending on the volume of the pyrolysis tank 1, but is approximately 300 liters when the pyrolysis tank 1 is for treating 1.5t of plastic waste.
[0013]
In order to freely supply or discharge residue and slop oil into the sealed residue receiving tank 25 and to prevent the high temperature residue from becoming oxides, Inlet 40 of inert gas such as nitrogen gas and exhaust port 41 are provided, and the supply and discharge thereof are controlled by the fifth on-off valve 42 and the flow rate control valve 43. An exhaust pipe 44 provided with the flow control valve 43 is connected to the exhaust port 41 so that the exhaust is exhausted at a position higher than the residue receiving tank 25.
[0014]
Prior to the thermal decomposition of plastic waste in the pyrolysis tank 1, the on-off valve 27 and the second on-off valve 30 are closed, the third on-off valve 32 is opened, the fifth on-off valve 42 and the flow control valve 43 are turned on. Open and the downstream discharge pipe 28b and the residue receiving tank 25 are filled with nitrogen gas A. Then, when the plastic waste charged in the pyrolysis tank 1 is melted, the screw conveyor 24 is operated, and the flow control valve 38 of the slop oil supply pipe 36 is slightly opened, and a little. The slop oil B is supplied to the upstream discharge pipe 28a. The operation of the screw conveyor 24 prevents the residue from concentrating and accumulating in the narrow part of the bottom of the pyrolysis tank 1, and the flow of the residue in the pipe by flowing slop oil through the discharge pipe 28a. Sex is maintained.
[0015]
When the thermal decomposition in the thermal decomposition tank 1 is completed, the flow control valve 35 is further opened appropriately and the on-off valve 33 is opened. Then, as shown in FIG. 3, the inside of the downstream discharge pipe 28b is filled with slop oil, and is filled to the extent that the pipe end of the discharge pipe 28b is immersed in the residue receiving tank 25. When pyrolysis is completed, metal components and minerals with high specific gravity are accumulated below the residue, and the metal components are bitten by the valve, causing failure of the valve. However, in the present invention, first, the flow rate of the slop oil supplied to the upstream discharge pipe 28a by the flow control valve 38 is set to 2 m ^3, for example. / H, so that a solid material such as a metal component having a large specific gravity is suspended in the slop oil in the discharge pipe 28a, the third on-off valve 32 and the flow rate adjustment valve 35 are opened, and the flow rate control valve 35 is For example, 1 m ³ / h of slop oil is introduced into the discharge pipe 28b on the downstream side, and the fourth on-off valve 33 is closed. If left as it is for a while, the residue having a large specific gravity that accumulates below in the unreacted portion of the melted plastic is mixed with the slop oil and becomes diluted and sinks in the oil even if there is no flow. It is discharged into the inside (FIG. 4). Since the ratio of the residue having a large specific gravity is not so large, the flow control valve 43 of the exhaust pipe 44 does not need to be particularly opened.
[0016]
As a result, the metal components and inorganic substances accumulated below are gently discharged to the residue tank 25 only by sedimentation due to gravity, and stick to or bite the on-off valves 27 and 32, causing trouble in closing the valve. Since it becomes difficult to solidify, the discharge pipe 28 is not clogged. In addition, since the unreacted components and the like are hot, if they are discharged as they are, there is a risk of damage to each on-off valve and the residual tank 25 due to heat shock, but since the slop oil is filled there, the heat shock is alleviated. Can prevent damage to the device.
[0017]
After discharging a residue having a large specific gravity such as a metal component, the flow rate control valve 43 of the exhaust pipe 44 is opened so as to obtain a nitrogen gas flow rate of 5 m ³ / h, for example, and at the same time, the flow rate control of the branch pipe 39 is performed. For example, if the valve 38 is greatly opened so that 5 m ³ / h of slop oil is supplied, a large amount of slop oil flows through the discharge pipe 28, and a low specific gravity such as a carbon residue in a floating state is accompanied by this flow. The inspection material can be extracted from the thermal decomposition tank 1 to the residue receiving tank 25 (FIG. 5). By supplying this slop oil, the carbon residue and the like can be extracted with the high-temperature pyrolysis oil in the pyrolysis tank 1 and screw conveyor 24 almost unchanged, and can be taken out as a safe liquid that does not cause an accident such as a fire.
[0018]
Even after most of the residue is taken out, the on-off valves 27 and 32 are cleaned by continuing the supply of slop oil to such an extent that it does not overflow into the residue receiving tank 25. The valve can be closed (FIG. 6).
[0019]
Thereafter, the on-off valve 27, the fourth on-off valve 33, the flow control valve 35 and the flow control valve 43 of the exhaust pipe 44 are closed while the third on-off valve 32 is open, and the second on-off valve 30 and the fifth on-off valve 42 are opened. When opened, the supply of slop oil to the discharge pipe 28b on the downstream side is cut off, and nitrogen gas is introduced into the residue receiving tank 25, so that the residue is discharged to the residue filter 31 together with the slop oil accumulated there. Then, the slop oil passes through the filter 31 and is collected in the slop oil tank 29, and the solid residue is captured by the filter 31 (FIG. 7). During this time, the flow control valve 38 of the branch pipe 39 is adjusted to allow a small amount of slop oil to flow into the thermal decomposition tank 1 and sufficiently dilute the liquid inside to prevent solidification and prepare for the next thermal decomposition.
[0020]
【Example】
1500 kg of crushed plastic waste is put into the pyrolysis tank 1, and at the same time, the heating medium heater 11 is operated, the reboiler 12 of the atmospheric distillation tower 9 is heated, and the bottom liquid is heated to about 280 ° C. The pump 17 was pumped to the ejector 8. The open / close valve 26 was closed to set the operation state in which the ejector 8 did not perform the suction operation, and the column bottom oil was returned to the column bottom 9a. When the heat exchanger 23 is heated by circulation of the bottom oil, the light oil prepared in the light oil tank 2 is pumped by the pump 16 and vaporized by the heat exchanger 23 at 279 ° C. The temperature was raised to ° C. and supplied to the jacket 4, and plastic waste was melted at 200 ° C. The composition of the plastic waste is 50 wt% polyethylene, 15 wt% polypropylene, 25 wt% polystyrene, and 10 wt% polyvinyl chloride. The operating conditions of the heating furnace 5 are a pressure of 1.9 kg / cm ² G and a light oil flow rate of 2000 kg / h. After the melting, the temperature is raised and the temperature in the pyrolysis tank 1 at 300 ° C. is maintained for 30 minutes. Chlorine gas generated at the initial stage of melting is sent to the dehydrochlorination tank 7 to perform dehydrochlorination treatment. 30 minutes after the completion, the temperature of the heating furnace 5 was raised, light oil vaporized at 410 ° C. was supplied into the tank, and the molten plastic waste was thermally decomposed. The pyrolysis product in the pyrolysis tank 1 is sent to the distillation tower 9 by the ejector 4 with a short residence time in the tank, and the top oil of the light oil component vaporized at about 170 ° C. is sent to the heat exchanger 14 and Condensed in the tower top liquid cooler 15 and stored in the light oil tank 2, heavy oil components that are liquid at 170 ° C. are stored in the tower bottom 9 a, and the pump 17 causes the ejector 4, the heating furnace 5, the flasher 19, and the dechlorination reaction. It was stored as heavy oil in the heavy oil tank 3 through the vessel 20 and the condenser 21.
[0021]
The pyrolysis time is 6 hours. During the pyrolysis, the screw conveyor 24 is operated and a small amount of slop oil is allowed to flow through the upstream discharge pipe 28a as shown in FIG. 2, and nitrogen gas is discharged downstream. Solidification of the residue such as carbon which was filled in the tube 28b and the residue receiving tank 25 and accumulated below the pyrolysis tank 1 was prevented. And after completion | finish of thermal decomposition, as shown in FIG. 3, the slop oil was filled in the residue receiving tank 25 to the extent that the inside of the downstream discharge pipe 28b was filled and the end of the discharge pipe was submerged. . Thereafter, the flow control valve 38 is adjusted to increase the amount of slop oil from the branch pipe 39 to 2 m ³ / h, and further 1 m ³ / h of slop oil is passed through the flow control valve 35 while leaving the residue floating. After the introduction and opening of the on-off valve 27, residues such as iron pieces and stones having a large specific gravity were submerged in the slop oil and taken out into the residue receiving tank 25. And the amount of slop oil introduced through the flow control valve 38 from the branch pipe 39 in a state of opening the opening and closing valve 27, 32 is increased to 5 m ³ / h, the flow rate control valve 43 of the discharge pipe 44 5 m ³ / The flow rate was adjusted to h. As a result, a residue having a small specific gravity is discharged into the residue receiving tank 25, and this state is maintained for 10 minutes to clean the on-off valves 27 and 32 with slop oil. The on-off valve 27, the fourth on-off valve 33, and the flow control valve 35 and 43 were closed.
[0022]
Next, the second on-off valve 30 was opened while introducing nitrogen gas, and the residue and slop oil stored in the residue receiving tank 25 were taken out to the residue filter 31, and only the slop oil was recovered in the slop oil tank 29. Since the on-off valve 27 and the third on-off valve 32 are washed with the slop oil, the valve can be reliably closed, and the pyrolytic oil is hardly mixed into the slop oil.
[0023]
【The invention's effect】
As described above, according to the present invention, the residue receiving tank is connected to the pipe end of the discharge pipe provided with an opening / closing valve for discharging the residue generated in the thermal decomposition tank due to the thermal decomposition of the plastic waste. A little slop oil is allowed to flow in the discharge pipe upstream of the on-off valve during the thermal decomposition, and after the thermal decomposition is completed, the discharge pipe on the downstream side of the on-off valve and the residue receiving tank are filled with slop oil. And then opening the on-off valve, and then increasing the amount of slop oil supplied to the discharge pipe upstream of the on-off valve to fully open the on-off valve and communicating the residue receiving tank to the slop oil tank, Solid matter that mixes with different specific gravity or is solidified due to a drop in temperature and clogs the discharge pipe or on / off valve, or bites into the on / off valve and obstructs the on / off operation. Residues including It is possible to improve the operation efficiency of the thermal decomposition tank, and the residue is not oxidized by introducing and discharging an inert gas into the residue receiving tank and discharging the residue. Ejection is facilitated, and the effect of appropriately implementing the method of the present invention can be obtained by using the apparatus configuration of claims 4 to 6.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of the thermal decomposition of plastic waste. FIG. 2 is an explanatory diagram of a residue removing device used for carrying out the method of the present invention. FIG. 3 is an explanatory diagram of a state of filling slop oil in FIG. FIG. 4 is an explanatory diagram of a state in which a residue having a high specific gravity is extracted. FIG. 5 is an explanatory diagram of a state in which a residue having a low specific gravity is extracted. FIG. Illustration of oil and residue separation state [Explanation of symbols]
1 Pyrolysis tank, 25 Residue receiving tank, 27 Open / close valve, 28 Discharge pipe, 28a Upstream discharge pipe, 28b Downstream discharge pipe, 29 Slop oil tank, 30 Second open / close valve, 31 Residual filter, 32 3 open / close valve, 33 4th open / close valve, 34 return line, 35/38/43 flow control valve, 36 slop oil supply pipe, 39 branch pipe, 40 inert gas inlet, 41 exhaust outlet, 42 fifth open / close valve 44 exhaust pipes,

Claims

Plastic waste is pyrolyzed in a pyrolysis tank, and gaseous pyrolysis products generated thereby are extracted to the outside and recovered as cracked oil. Residues accumulated at the bottom of the pyrolysis tank are opened and closed. In the oiling treatment method of discharging to the outside of the pyrolysis tank through a downwardly extending discharge pipe provided with a residual pipe receiving tank is connected to the pipe end of the discharge pipe, and the opening and closing during the pyrolysis Pour some slop oil from the outside into the discharge pipe on the upstream side of the valve, and after completion of the thermal decomposition, fill the discharge pipe on the downstream side of the on-off valve and the residue receiving tank with the slop oil, then open the on-off valve, A plastic waste characterized by increasing the amount of slop oil supplied to a discharge pipe upstream of the on-off valve, fully opening the on-off valve and communicating the residue receiving tank to a slop oil tank to discharge the residue Residue removal method in waste oil treatment.

The bottom of the residue receiving tank is a cone-shaped sealed container, and the pipe end of the discharge pipe extends to the bottom of the residue receiving tank and is connected to the discharge pipe upstream of the on-off valve during the thermal decomposition. While flowing some slop oil from the outside, an inert gas is introduced into the residue receiving tank, and after the thermal decomposition is completed, when the slop oil is filled into the discharge pipe and the residue receiving tank on the downstream side of the on-off valve, A part of the inert gas in the residual tank is discharged, and when the residual tank is opened to a slop oil tank and the residual matter is discharged, the inert gas is introduced into the residual tank. 2. A method for removing a residue in an oily treatment of plastic waste according to 1.

3. The method for removing a residue in an oily treatment of plastic waste according to claim 2, wherein the inert gas is nitrogen gas.

Plastic waste is pyrolyzed in a pyrolysis tank, and gaseous pyrolysis products generated thereby are extracted to the outside and recovered as cracked oil. Residues accumulated at the bottom of the pyrolysis tank are opened and closed. In the oil processing apparatus which discharges to the residue receiving tank outside the thermal decomposition tank through the downwardly extending discharge pipe provided with the slop oil is stored in the bottom of the residue receiving tank through the second on-off valve. A slop oil tank is connected, a third on-off valve is provided in the discharge pipe on the downstream side of the on-off valve, a discharge pipe between the on-off valve and the third on-off valve is connected to a branch line provided with the fourth on-off valve. A slop oil supply pipe provided with a flow control valve from the slop oil tank to a discharge pipe upstream of the on-off valve and a discharge pipe between the fourth on-off valve and the branch pipe For the oily treatment of plastic waste, characterized in that That the remaining 査物 removal device.

The residue receiving tank is composed of a sealed container having an inert gas introduction port and a discharge port, the discharge pipe is connected to the bottom of the residue receiving tank, and the residue receiving tank and the slop oil tank are connected to each other. The residue removal device in the plastic waste oiling process according to claim 4, wherein the residue is connected via a second opening / closing valve and a residue filter.

The residue discharge device in the plastic waste oiling process according to claim 4, wherein the discharge pipe is connected to an extrusion port of a screw conveyor provided at the bottom of the pyrolysis tank.