JP2004238508A - Method for utilizing gas of melting furnace for gasification - Google Patents

Method for utilizing gas of melting furnace for gasification Download PDF

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JP2004238508A
JP2004238508A JP2003029412A JP2003029412A JP2004238508A JP 2004238508 A JP2004238508 A JP 2004238508A JP 2003029412 A JP2003029412 A JP 2003029412A JP 2003029412 A JP2003029412 A JP 2003029412A JP 2004238508 A JP2004238508 A JP 2004238508A
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gas
gasification
melting furnace
cog
fuel
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Yoshimoto Fujii
良基 藤井
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JFE Steel Corp
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JFE Steel Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/78—Recycling of wood or furniture waste

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the used amount of a fuel purchased from outside by utilizing a gas of a melting furnace for gasification as flame-stabilizing fuel for a powder boiler to reduce an energy cost. <P>SOLUTION: This method for utilizing the gas of the melting furnace for the gasification comprises mixing a gas 7a generated by the melting furnace 7 for the gasification, for thermally cracking a combustible waste in a high-temperature reducing atmosphere to gasify and melt the waste, with a gas 4a having ≥30 MJ/Nm<SP>3</SP>calorific value such as a natural gas (LNG) and a liquefied petroleum gas (LPG), and utilizing the mixed gas as the fuel in iron works. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば使用済みプラスチックなどの可燃性廃棄物を高温還元雰囲気により熱分解・ガス化溶融するガス化溶融炉で発生するガスを有効に利用する方法に関する。
【０００２】
【従来の技術】
製鉄所で発生するコークス炉ガス（ＣＯＧ）は、鋼材加熱炉やコークス炉など製鉄プロセスの燃料として使用される他に、発電ボイラの保炎燃料として利用されている。発電ボイラでは、火炉での安定燃焼を維持するために、ボイラの最大蒸気発生量を維持するのに必要な燃焼熱量のうち、１０％以上を常に高カロリ燃料で燃焼させなければならない。この１０％相当の燃料を保炎燃料と言う。
【０００３】
一般に、ＣＯＧの発生量に対して製鉄プロセスで必要なＣＯＧ量を差し引いた残りのＣＯＧが発電所に供給される。従って、発電所に送られるＣＯＧ量が保炎燃料未満となると不足分を補わなくてはならず、従来はこの不足分を全て重油、都市ガス（天然ガス：ＬＮＧ）、液化石油ガス（ＬＰＧ）等の高カロリの外部購入燃料により補い、これら外部購入燃料を保炎燃料の一部として発電ボイラで燃焼させ、安定燃焼を維持するようにしている。
【０００４】
ところで、従来より高温の炉内において、使用済みプラスチック、建設廃材（紙くず、木くず、繊維くず）、シュレッダーダスト（廃棄家電、廃車）、汚泥、燃えがら、動植物性残さ等の可燃性廃棄物を送風酸素と反応させ、炉上部温度を８００〜１０００℃とし、高温・還元雰囲気により熱分解・ガス化させ、可燃性のガス化溶融炉ガスとして回収するガス化溶融炉は知られている（例えば特許文献１参照）。
【０００５】
【特許文献１】
特開平９−６０８３０号公報
【０００６】
【発明が解決しようとする課題】
前述したように、製鉄プロセスで使用するＣＯＧ量が増え、相対的に発電所に保炎燃料としてまわすＣＯＧの量が不足すると、保炎燃料をＣＯＧで確保することができなくなるため、従来は高カロリの外部購入燃料により不足分を全て補って製鉄所の操業を行なっている。このため、エネルギコストが上昇する。
【０００７】
一方、ガス化溶融炉ガスは、発熱量が１０ＭＪ／Ｎｍ３ 程度でそのままではＣＯＧ代替のガスにはならず、かつ水素、ＣＯ主体のガスのため、燃焼速度が速く、ＣＯＧバーナでガス化溶融炉ガスを燃焼させると、バーナ手前で燃焼反応が完結し、バーナチップ近傍で高温燃焼火炎が形成されるためにバーナが溶損する。
【０００８】
したがって、従来はせっかく回収したガス化溶融炉ガスを、有効に利用することなく焼却処理し、無害化して大気に放散していた。また、燃焼させる際には補助燃料の供給が必要であり、ランニングコストも発生していた。
【０００９】
本発明の技術的課題は、ガス化溶融炉ガスを発電ボイラの保炎燃料として利用できるようにして、外部購入燃料の使用量を削減し、エネルギコストの低減化を図れるようにすることにある。
【００１０】
【課題を解決するための手段】
本発明の請求項１に係るガス化溶融炉ガスの利用方法は、可燃性廃棄物を高温還元雰囲気により熱分解・ガス化溶融するガス化溶融炉で発生するガスを、天然ガス（ＬＮＧ）や液化石油ガス（ＬＰＧ）など３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合し、製鉄所内燃料として利用することを特徴としている。
【００１１】
また、請求項２に係るガス化溶融炉ガスの利用方法は、ガス化溶融炉ガスを、ガスホルダを介在させた配管網を通して３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合することを特徴としている。
【００１２】
また、請求項３に係るガス化溶融炉ガスの利用方法は、ガス化溶融炉ガスを、３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合する前に昇圧することを特徴としている。
【００１３】
また、請求項４に係るガス化溶融炉ガスの利用方法は、ガス化溶融炉ガスと３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスとの混合によって、コークス炉ガス相当の模擬コークス炉ガスとした後、この模擬コークス炉ガスを、コークス炉ガス配管へ接続することで、製鉄所内燃料として利用することを特徴としている。
【００１４】
また、請求項５に係るガス化溶融炉ガスの利用方法は、ガス化溶融炉ガスを３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合する際に、混合後のガスの発熱量がＣＯＧ相当の１５〜２５ＭＪ／Ｎｍ３ となるように、混合量が調整されてなることを特徴としている。
【００１５】
また、請求項６に係るガス化溶融炉ガスの利用方法は、ガス化溶融炉ガスを３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合する際に、混合後のガスの燃焼速度がＣＯＧ相当となるように、混合量が調整されてなることを特徴としている。
【００１６】
【発明の実施の形態】
以下、図示実施形態に基づき本発明のガス化溶融炉ガスの利用方法を説明する。図１は本発明を適用した製銑・製鋼一貫製鉄所における燃料の流れを示す図である。
【００１７】
図において、１は操業時に高炉ガス（ＢＦＧ）１ａを副生する高炉、２は操業時にコークス炉ガス（ＣＯＧ）２ａを副生するコークス炉、３は操業時に転炉ガス（ＬＤＧ）３ａを副生する転炉である。高炉ガス（ＢＦＧ）１ａは、鉄鉱石を還元する際に発生するＣＯ，ＣＯ２，Ｈ２，Ｎ２から成る約３，３５０ｋＪ／ｍ３の可燃性ガスであり、ほぼ連続的に発生する。コークス炉ガス（ＣＯＧ）２ａは、石炭を乾留する際に発生するＨ２，ＣＨ４，ＣＯから成る約２０，１００ｋＪ／ｍ３の可燃性ガスであり、ほぼ連続的に発生する。転炉ガス（ＬＤＧ）３ａは、銑鉄を鋼に改質する際に発生するＣＯ，ＣＯ２ から成る約８，４００ｋＪ／ｍ３ の可燃性ガスであり、間欠的に発生する。つまり転炉の吹練によりガスの発生がつねに変動する。
【００１８】
４ａは３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスすなわち外部購入燃料である都市ガス（天然ガス：ＬＮＧ）または液化石油ガス（プロパンガス：ＬＰＧ）、５ａは窒素（Ｎ２） 、６は外部購入燃料である重油６ａの供給源である重油タンクである。ＬＮＧまたはＬＰＧは、主に後述のガス化溶融炉ガスと共に模擬コークス炉ガスの製造原料ガスとして使用されるが、それ以外にも、ガス化溶融炉ガスが発生・貯蔵がなくかつ発電所に保炎燃料としてまわすＣＯＧの量が不足した場合に不足分を補充する目的で使用される。Ｎ２ は高カロリーのＬＮＧまたはＬＰＧが前記補充目的で使用される場合に希釈用として用いられる。重油は発電所の燃料として供給される。
【００１９】
７はガス化溶融炉であって、既述したように高温の炉内において、使用済みプラスチック、建設廃材（紙くず、木くず、繊維くず）、シュレッダーダスト（廃棄家電、廃車）、汚泥、燃えがら、動植物性残さ等の可燃性廃棄物を送風酸素と反応させ、炉上部温度を８００〜１０００℃とし、高温・還元雰囲気により熱分解・ガス化させ、可燃性のガス化溶融炉ガス７ａとして回収するもので、発生ガスの性状は約８，０００〜１１，０００ｋＪ／ｍ３ であり、炉下部においては、コークス及び炭素の燃焼により、灰分を溶融し、出滓口より排出するものである。回収されたガス化溶融炉ガス７ａは、全て模擬コークス炉ガスの製造原料ガスとして使用される。
【００２０】
１１，１２，１３，１４は各炉で発生する可燃ガス（燃料ガス）を無害化・燃焼放散するための燃焼放散塔すなわちフレアスタックであり、通常は使用しないが、各炉の起動・停止時のガス成分不安定時や、各炉に対応して設けられた後述のホルダの備蓄レベルが上限をオーバーした時などに使用される。
【００２１】
２１は高炉ガス（ＢＦＧ）を一時貯蔵しバッファとして機能するＢＦＧホルダ、２２はコークス炉ガス（ＣＯＧ）を一時貯蔵しバッファとして機能するＣＯＧホルダ、２３は転炉ガス（ＬＤＧ）を一時貯蔵しバッファとして機能するＬＤＧホルダ、２４はガス化溶融炉ガス７ａを一時貯蔵しバッファとして機能するガス化溶融炉ガスホルダである。これらホルダ２１〜２４は内部ガス圧力が６５ｋＰａ と低圧に保持されている。
【００２２】
３１，３２，３３はＢＦＧ配管、ＣＯＧ配管、及びＬＤＧ配管にそれぞれ配置された昇圧機すなわちブロワで、これらブロワ３１〜３３は、それぞれのガスの圧力を約６５ｋＰａから約１２０ｋＰａに昇圧して、後述するガスミキサーに供給する機能を有する。３４はガス化溶融炉ガス配管網においてガス化溶融炉ガスホルダ２４の下流側に直列に配置された昇圧機すなわちブロワである。ブロワ３４をガス化溶融炉ガスホルダ２４に対して直列に接続したのは、既述したようにガス化溶融炉７では種々の可燃性廃棄物からガス化溶融炉ガス７ａを回収するので、ガス発生量が一定でなく圧力変動を生じるため、ガス混合器前に昇圧機を配置して、後述する模擬ＣＯＧミキサーに供給するガス化溶融炉ガスを安定化させる必要があるからである。
【００２３】
ＬＮＧまたはＬＰＧの配管は、二股に分かれ、二股の一方の流路が模擬ＣＯＧミキサー６０に接続され、二股の他方の流路がガスミキサー９に接続され、それぞれの流路に流量調整可能な切替弁６１，６２が設けられている。そして、通常は切替弁６１，６２によって模擬ＣＯＧミキサー６０側に繋がるＬＮＧまたはＬＰＧの配管網が形成され、かつ後述の演算器の出力に応じて模擬ＣＯＧミキサー側の切替弁６１の開度（流量）が自動調整されるようになっている。いずれにせよ切替弁６１，６２は遠隔操作可能とすることが望ましい。
【００２４】
また、模擬ＣＯＧミキサー６０には、ガス化溶融炉ガス配管が接続され、ブロワ３４により昇圧されたガス化溶融炉ガスが供給されるようになっている。つまり、模擬ＣＯＧミキサー６０は、ガス化溶融炉ガスを、３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガス（ＬＮＧやＬＰＧ）４ａと混合することで、ＣＯＧ相当のガスにするために設けられたもので、混合後のガスの発熱量が１５〜２５ＭＪ／Ｎｍ３ となるように混合量を調整し、あるいは混合後のガスの燃焼速度がＣＯＧ相当となるように混合量を調整する機能を有する。例えば、天然ガス（ＬＮＧ）は、メタンガス主体のガスであり燃焼速度が遅く、ガス化溶融炉ガスに混合することで、ガス化溶融炉ガス単独で燃焼する場合に比べて燃焼速度を低下させることができる。また、ＬＰＧは、プロパンまたはブタン主体のガスであり、どちらも燃焼速度が遅く、ガス化溶融炉ガスに混合することで、ガス化溶融炉ガス単独で燃焼する場合に比べて燃焼速度を低下させることができる。そして、このようにＣＯＧ相当のガスに調整された混合ガスである模擬ＣＯＧ６０ａは、ＣＯＧ配管におけるＣＯＧホルダ２２よりも下流側に戻されて、製鉄所内燃料として、あるいは後述のミックスガス（ＭＸＧ）製造原料ガスとして利用されるようになっている。なお、安定的にＣＯＧ（ＣＯＧ単独やＣＯＧ＋模擬ＣＯＧを含む）２ａが供給可能な熱量に相当する鋼材加熱炉のある鋼管や条鋼の工場４１へは、ＣＯＧ２ａを直接供給し、ガス搬送動力費用を削減できるようにしている。
【００２５】
また、模擬ＣＯＧ配管に、混合ガス（模擬ＣＯＧ）の発熱量を計測可能な発熱量計やガスクロマトグラフィ等からなる模擬ＣＯＧセンサ６５を配置するとともに、ＣＯＧ配管における模擬ＣＯＧ配管との接続部よりも上流側に、ＣＯＧの発熱量を計測可能な発熱量計やガスクロマトグラフィ等からなるＣＯＧセンサ６６を配置し、さらにこれらセンサ６５，６６の検出値から模擬ＣＯＧの発熱量がＣＯＧと等価になるようにＬＮＧまたはＬＰＧの混合量を演算する演算器６７を設け、演算器６７にてＬＮＧまたはＬＰＧの混合量を演算し図示しないドライバを介して切替弁６１の開度（流量）を調整するようになっている。また演算器６７は、模擬ＣＯＧセンサ６５とＣＯＧセンサ６６の検出値からガス化溶融炉ガスの発生・貯蔵がなくかつ発電所に保炎燃料としてまわすＣＯＧの量が不足していると判断すると、そのことをオペレータに通知するとともに切替弁６１を閉じさせる機能も有する。
【００２６】
９は各ブロワ３１〜３３により昇圧されたＢＦＧ１ａ、ＣＯＧ（ＣＯＧ単独やＣＯＧ＋模擬ＣＯＧを含む）２ａ、ＬＤＧ３ａや、外部購入燃料（ＬＮＧまたはＬＰＧ）４ａ、及び窒素（Ｎ２）５ａ が送り込まれるガスミキサーである。このガスミキサー９は、送り込まれた各種ガスによる発熱量変動を吸収し、燃料性状を安定させたミックスガス（ＭＸＧ）９ａとして製鉄所内の各工場、つまり製銑工場４２、製鋼工場４３、鋼板工場４４や発電所４５へ供給する機能を有している。
【００２７】
発電所４５には、ミックスガス（ＭＸＧ）９ａ以外に、高炉ガス（ＢＦＧ）１ａ、コークス炉ガス（ＣＯＧ単独やＣＯＧ＋模擬ＣＯＧを含む）２ａ、及び転炉ガス（ＬＤＧ）３ａが直接供給可能になっている。これは各ガスの発生量の変動を吸収するためのもので、ガスミキサー９への供給後に余剰のガスがあった場合、これを発電燃料として使用している。また、外部購入燃料である重油６ａも供給可能になっている。そして、各燃料種に応じたバーナを有するボイラ及びタービンが設置されている。つまり、発電所４５では、ミックスガス（ＭＸＧ）の他に、高炉ガス（ＢＦＧ）、コークス炉ガス（ＣＯＧ単独やＣＯＧ＋模擬ＣＯＧを含む）、及び転炉ガス（ＬＤＧ）を燃料ガスとしているが、通常は不足分として重油を供給して発電している。なお、バーナとして燃料の発熱量変動に耐用性がある管状火炎バーナを採用すれば、使用するバーナの数を減らせることは言うまでもない。
【００２８】
本実施形態のように、ガス化溶融炉ガス７ａを模擬コークス炉ガスの製造原料ガスとして使用することにより、外部購入燃料であるＬＮＧまたはＬＰＧの使用量を削減することができ、エネルギコスト削減が可能となる。
【００２９】
なお、前述の実施形態では模擬ＣＯＧミキサー６０にて混合させるガスは、ＬＮＧまたはＬＰＧのいずれか一方であるものを例に挙げて説明したが、ＬＮＧまたはＬＰＧの両方を使用してガスの混合量を調整することもできる。その場合は、どちらかのガスを一定量流して、他方の流量を調整することで混合ガスの発熱量をＣＯＧ相当にする。
【００３０】
【発明の効果】
以上述べたように、本発明によれば、可燃性廃棄物を高温還元雰囲気により熱分解・ガス化溶融するガス化溶融炉で発生するガスを、天然ガス（ＬＮＧ）や液化石油ガス（ＬＰＧ）など３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合し、製鉄所内燃料として利用するようにしたので、外部購入燃料の使用量を削減できて、エネルギコストの低減化を図ることができた。
【図面の簡単な説明】
【図１】本発明のガス化溶融炉ガスの利用方法を適用した製銑・製鋼一貫製鉄所における燃料の流れを示す図である。
【符号の説明】
２ コークス炉
２ａ コークス炉ガス（ＣＯＧ）
４ａ ＬＮＧやＬＰＧ（３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガス）
７ ガス化溶融炉
７ａ ガス化溶融炉ガス
２４ ガス化溶融炉ガスホルダ（ガスホルダ）
３４ ブロワ（昇圧手段）
６０ 模擬ＣＯＧミキサー
６０ａ 模擬ＣＯＧ（混合後のガス）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for effectively utilizing gas generated in a gasification and melting furnace for pyrolyzing and gasifying and melting combustible waste such as used plastics in a high-temperature reducing atmosphere.
[0002]
[Prior art]
BACKGROUND ART Coke oven gas (COG) generated in an ironworks is used not only as a fuel for an iron making process such as a steel heating furnace or a coke oven, but also as a flame holding fuel for a power generation boiler. In a power generation boiler, in order to maintain stable combustion in a furnace, 10% or more of the heat of combustion required to maintain the maximum steam generation amount of the boiler must always be burned with high calorie fuel. The fuel equivalent to 10% is called flame holding fuel.
[0003]
Generally, the remaining COG obtained by subtracting the amount of COG required in the iron making process from the amount of generated COG is supplied to the power plant. Therefore, if the amount of COG sent to the power plant is less than the flame-holding fuel, it is necessary to make up for the shortage. Conventionally, all of this shortage has been compensated for by heavy oil, city gas (natural gas: LNG), and liquefied petroleum gas (LPG). Such fuels are supplemented with high-calorie externally purchased fuels, and these externally purchased fuels are burned as part of the flame-holding fuel in a power generation boiler to maintain stable combustion.
[0004]
By the way, flammable waste such as used plastic, construction waste (paper waste, wood waste, fiber waste), shredder dust (waste electrical appliances, waste vehicles), sludge, cinders, animal and plant residues, etc. is blown in a furnace at a higher temperature than before. A gasification and melting furnace is known in which a furnace upper temperature is set to 800 to 1000 ° C., pyrolyzed and gasified in a high-temperature and reducing atmosphere, and recovered as a flammable gasification and melting furnace gas (for example, Patent Document 1). 1).
[0005]
[Patent Document 1]
JP-A-9-60830
[Problems to be solved by the invention]
As described above, if the amount of COG used in the steelmaking process increases and the amount of COG passed to the power plant as flame holding fuel becomes relatively short, it becomes impossible to secure the flame holding fuel with COG. The company operates the steel mill to make up for the shortfall with fuel purchased from outside calories. For this reason, energy costs increase.
[0007]
On the other hand, the gasification melting furnace gases, in an intact heating value 10 MJ / Nm 3 about not become a COG alternative gas, and hydrogen, for CO main gas, fast burning rate, gasification melting at COG burner When the furnace gas is burned, the combustion reaction is completed before the burner, and a high-temperature combustion flame is formed near the burner tip, so that the burner is melted.
[0008]
Therefore, conventionally, the gasification and melting furnace gas collected with great care was incinerated without being effectively used, rendered harmless, and released to the atmosphere. In addition, when burning, it is necessary to supply auxiliary fuel, and running costs have also been incurred.
[0009]
A technical object of the present invention is to make it possible to use gasification and melting furnace gas as a flame holding fuel of a power generation boiler, to reduce the amount of fuel purchased from outside, and to reduce energy costs. .
[0010]
[Means for Solving the Problems]
The method of using a gasification and melting furnace gas according to claim 1 of the present invention is characterized in that a gas generated in a gasification and melting furnace for pyrolyzing and gasifying and melting combustible waste in a high-temperature reducing atmosphere is converted into natural gas (LNG) or the like. It is characterized by being mixed with a gas having a calorific value of 30 MJ / Nm3 or more, such as liquefied petroleum gas (LPG), and used as fuel in steelworks.
[0011]
Further, the method of using the gasification / melting furnace gas according to claim 2 is characterized in that the gasification / melting furnace gas is mixed with a gas having a calorific value of 30 MJ / Nm3 or more through a piping network having a gas holder interposed. And
[0012]
The method of using the gasification / melting furnace gas according to claim 3 is characterized in that the gasification / melting furnace gas is pressurized before being mixed with a gas having a calorific value of 30 MJ / Nm3 or more.
[0013]
Further, the method of using the gasification and melting furnace gas according to claim 4 is that the gasification and melting furnace gas is mixed with a simulated coke oven gas equivalent to a coke oven gas by mixing the gasification melting furnace gas and a gas having a calorific value of 30 MJ / Nm3 or more. After that, the simulated coke oven gas is connected to a coke oven gas pipe to be used as fuel in a steelworks.
[0014]
Further, in the method of using the gasification and melting furnace gas according to claim 5, when the gasification and melting furnace gas is mixed with a gas having a heating value of 30 MJ / Nm3 or more, the calorific value of the gas after mixing is COG. It is characterized in that the mixing amount is adjusted so as to be considerably 15 to 25 MJ / Nm 3 .
[0015]
Further, in the method of using the gasification / melting furnace gas according to claim 6, when the gasification / melting furnace gas is mixed with a gas having a calorific value of 30 MJ / Nm3 or more, the combustion speed of the mixed gas is COG. It is characterized in that the mixing amount is adjusted so as to be considerable.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method of using the gasification and melting furnace gas of the present invention will be described based on the illustrated embodiment. FIG. 1 is a diagram showing the flow of fuel in an integrated iron and steelmaking steelworks to which the present invention is applied.
[0017]
In the figure, reference numeral 1 denotes a blast furnace that produces by-product blast furnace gas (BFG) 1a during operation, 2 denotes a coke oven that produces by-product coke oven gas (COG) 2a during operation, and 3 denotes a converter furnace that produces converter gas (LDG) 3a during operation. It is a converter that produces. The blast furnace gas (BFG) 1a is a flammable gas of about 3,350 kJ / m 3 composed of CO, CO 2 , H 2 , and N 2 generated when reducing iron ore, and is generated almost continuously. The coke oven gas (COG) 2a is a flammable gas of about 20,100 kJ / m 3 composed of H 2 , CH 4 , and CO generated when carbonizing coal, and is generated almost continuously. The converter gas (LDG) 3a is a combustible gas of about 8,400 kJ / m 3 composed of CO and CO 2 generated when pig iron is reformed into steel, and is generated intermittently. That is, the gas generation always fluctuates due to the blowing of the converter.
[0018]
4a is a gas having a calorific value of 30 MJ / Nm 3 or more, that is, city gas (natural gas: LNG) or liquefied petroleum gas (propane gas: LPG) which is an externally purchased fuel, 5a is nitrogen (N 2 ), and 6 is external It is a heavy oil tank that is a supply source of the heavy oil 6a that is the purchased fuel. LNG or LPG is mainly used as a raw material gas for producing a simulated coke oven gas together with the gasification / melting furnace gas described below, but other than that, no gasification / melting furnace gas is generated / stored and stored in the power plant. It is used for the purpose of supplementing the shortage when the amount of COG used as flame fuel is insufficient. N 2 is used as a diluent if the LNG or LPG high-calorie is used in the replenishment purposes. Fuel oil is supplied as fuel for the power plant.
[0019]
Reference numeral 7 denotes a gasification and melting furnace. As described above, in a high-temperature furnace, used plastic, construction waste (paper waste, wood waste, textile waste), shredder dust (waste electrical appliances, waste vehicles), sludge, cinders, animals and plants. Reacts combustible waste such as flammable residues with blast oxygen, raises the furnace upper temperature to 800 to 1000 ° C, pyrolyzes and gasifies it in a high-temperature, reducing atmosphere, and recovers it as combustible gasification and melting furnace gas 7a. in the properties of the generated gas is about 8,000~11,000kJ / m 3, in the lower part of the furnace, the combustion of coke and carbon, melting the ash, is intended to discharge from Dekasuguchi. The recovered gasification and melting furnace gas 7a is all used as a raw material gas for producing a simulated coke oven gas.
[0020]
Numerals 11, 12, 13, and 14 denote combustion stripping towers or flare stacks for detoxifying and burning off combustible gas (fuel gas) generated in each furnace, which is not normally used, but is used when starting and stopping each furnace. It is used when the gas component is unstable or when the stock level of a holder, which will be described later, provided for each furnace exceeds the upper limit.
[0021]
21 is a BFG holder that temporarily stores blast furnace gas (BFG) and functions as a buffer, 22 is a COG holder that temporarily stores coke oven gas (COG) and functions as a buffer, and 23 is a buffer that temporarily stores converter gas (LDG). The LDG holder 24 functions as a gasification melting furnace gas holder that temporarily stores the gasification melting furnace gas 7a and functions as a buffer. The holders 21 to 24 are maintained at a low internal gas pressure of 65 kPa.
[0022]
Reference numerals 31, 32, and 33 denote boosters or blowers arranged in the BFG pipe, the COG pipe, and the LDG pipe, respectively. These blowers 31 to 33 increase the pressure of each gas from about 65 kPa to about 120 kPa. It has a function of supplying to a gas mixer. Reference numeral 34 denotes a pressure booster or blower arranged in series in the gasification and melting furnace gas piping network downstream of the gasification and melting furnace gas holder 24. The reason why the blower 34 is connected in series to the gasification / melting furnace gas holder 24 is that the gasification / melting furnace 7 recovers the gasification / melting furnace gas 7a from various combustible wastes as described above. This is because, since the amount is not constant and pressure fluctuation occurs, it is necessary to arrange a pressure booster in front of the gas mixer to stabilize the gasification and melting furnace gas supplied to the simulated COG mixer described later.
[0023]
The LNG or LPG pipe is divided into two branches, one of the two branches is connected to the simulated COG mixer 60, the other of the two branches is connected to the gas mixer 9, and the flow rate of each of the flow paths can be adjusted. Valves 61 and 62 are provided. Normally, an LNG or LPG piping network connected to the simulated COG mixer 60 is formed by the switching valves 61 and 62, and the opening (flow rate) of the simulated COG mixer-side switching valve 61 is determined according to the output of a computing unit described later. ) Is automatically adjusted. In any case, it is desirable that the switching valves 61 and 62 can be remotely operated.
[0024]
Further, a gasification / melting furnace gas pipe is connected to the simulated COG mixer 60 so that the gasification / melting furnace gas pressurized by the blower 34 is supplied. In other words, the simulated COG mixer 60 is provided for mixing the gasification and melting furnace gas with a gas (LNG or LPG) 4a having a calorific value of 30 MJ / Nm 3 or more, thereby obtaining a COG equivalent gas. It has a function of adjusting the mixing amount so that the calorific value of the mixed gas becomes 15 to 25 MJ / Nm 3 or adjusting the mixing amount so that the combustion speed of the mixed gas becomes equivalent to COG. . For example, natural gas (LNG) is a gas mainly composed of methane gas and has a low combustion rate. By mixing with natural gas for gasification and melting, the combustion rate is reduced as compared with the case of burning with gasification and melting furnace gas alone. Can be. Further, LPG is a gas mainly composed of propane or butane, and both have a low combustion rate, and when mixed with the gasification and melting furnace gas, lower the combustion rate as compared with the case where the gasification and melting furnace gas is used alone. be able to. Then, the simulated COG 60a, which is a mixed gas adjusted to a gas equivalent to COG, is returned to the COG pipe downstream of the COG holder 22, and is used as fuel in a steel mill or a mixed gas (MXG) described later. It is used as a source gas. In addition, COG 2a is directly supplied to a steel pipe or steel bar factory 41 having a steel heating furnace corresponding to the amount of heat that can be stably supplied by COG (including COG alone or COG + simulated COG) 2a, and the gas transfer power cost is reduced. We are trying to reduce it.
[0025]
In addition, a simulated COG sensor 65 composed of a calorimeter or gas chromatography capable of measuring the calorific value of the mixed gas (simulated COG) is arranged in the simulated COG pipe, and the simulated COG pipe is connected to the simulated COG pipe at a position closer to the simulated COG pipe. A COG sensor 66 composed of a calorimeter or gas chromatography capable of measuring the calorific value of COG is arranged on the upstream side, and the calorific value of the simulated COG is equivalent to COG based on the detection values of these sensors 65 and 66. Is provided with a calculator 67 for calculating the mixture amount of LNG or LPG, the calculator 67 calculates the mixture amount of LNG or LPG, and adjusts the opening degree (flow rate) of the switching valve 61 via a driver (not shown). Has become. When the arithmetic unit 67 determines from the detection values of the simulated COG sensor 65 and the COG sensor 66 that there is no generation and storage of gasification and melting furnace gas and that the amount of COG to be passed to the power plant as flame holding fuel is insufficient, It also has a function of notifying the operator of this and closing the switching valve 61.
[0026]
Reference numeral 9 denotes a gas into which BFG 1a, COG (including COG alone or COG + simulated COG) 2a, LDG 3a, externally purchased fuel (LNG or LPG) 4a, and nitrogen (N 2 ) 5a which are pressurized by the blowers 31 to 33 are sent. It is a mixer. The gas mixer 9 absorbs fluctuations in the calorific value due to the various gases sent in, and as a mixed gas (MXG) 9a in which the fuel properties are stabilized, the various factories in the steel mill, that is, the pig iron factory 42, the steel factory 43, and the steel sheet factory. It has a function of supplying the power to the power plant 44 and the power plant 45.
[0027]
In addition to the mixed gas (MXG) 9a, blast furnace gas (BFG) 1a, coke oven gas (including COG alone or COG + simulated COG) 2a, and converter gas (LDG) 3a can be directly supplied to the power plant 45. Has become. This is to absorb fluctuations in the generation amount of each gas, and when there is excess gas after being supplied to the gas mixer 9, this gas is used as power generation fuel. Also, heavy oil 6a, which is an externally purchased fuel, can be supplied. A boiler and a turbine having a burner corresponding to each fuel type are installed. That is, in the power plant 45, in addition to the mixed gas (MXG), the blast furnace gas (BFG), the coke oven gas (including COG alone or COG + simulated COG), and the converter gas (LDG) are used as fuel gas. Normally, heavy oil is supplied as a shortage to generate electricity. It is needless to say that the number of burners to be used can be reduced by adopting a tubular flame burner that is durable against fluctuations in the calorific value of the fuel.
[0028]
As in the present embodiment, by using the gasification and melting furnace gas 7a as a raw material gas for producing a simulated coke oven gas, it is possible to reduce the amount of LNG or LPG that is an externally purchased fuel, thereby reducing energy costs. It becomes possible.
[0029]
In the above-described embodiment, the gas to be mixed by the simulated COG mixer 60 is described as an example of one of LNG and LPG. However, the mixing amount of the gas using both LNG and LPG is described. Can also be adjusted. In that case, the calorific value of the mixed gas is made to correspond to COG by adjusting the flow rate of one of the gases and adjusting the flow rate of the other gas.
[0030]
【The invention's effect】
As described above, according to the present invention, natural gas (LNG) or liquefied petroleum gas (LPG) is generated by a gasification and melting furnace that thermally decomposes and gasifies combustible waste in a high-temperature reducing atmosphere. For example, by mixing with a gas having a calorific value of 30 MJ / Nm 3 or more and using it as fuel in steelworks, it was possible to reduce the amount of externally purchased fuel and reduce energy costs. .
[Brief description of the drawings]
FIG. 1 is a diagram showing the flow of fuel in an integrated iron and steelmaking steelworks to which a method for utilizing gasification and melting furnace gas of the present invention is applied.
[Explanation of symbols]
2 Coke oven 2a Coke oven gas (COG)
4a LNG and LPG (gas with a calorific value of 30 MJ / Nm 3 or more)
7 Gasification and melting furnace 7a Gasification and melting furnace gas 24 Gasification and melting furnace gas holder (gas holder)
34 blower (pressurizing means)
60 Simulated COG mixer 60a Simulated COG (gas after mixing)

Claims (6)

可燃性廃棄物を高温還元雰囲気により熱分解・ガス化溶融するガス化溶融炉で発生するガスを、天然ガス（ＬＮＧ）や液化石油ガス（ＬＰＧ）など３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合し、製鉄所内燃料として利用することを特徴とするガス化溶融炉ガスの利用方法。The gas generated in a gasification and melting furnace that thermally decomposes and gasifies combustible waste in a high-temperature reducing atmosphere has a heating value of 30 MJ / Nm3 or more, such as natural gas (LNG) or liquefied petroleum gas (LPG). A method for using a gasification and melting furnace gas, which is mixed with a gas and used as a fuel in an ironworks. ガス化溶融炉ガスを、ガスホルダを介在させた配管網を通して３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合することを特徴とする請求項１記載のガス化溶融炉ガスの利用方法。2. The method according to claim 1, wherein the gasification furnace gas is mixed with a gas having a calorific value of 30 MJ / Nm3 or more through a piping network having a gas holder interposed therebetween. ガス化溶融炉ガスを、３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合する前に昇圧することを特徴とする請求項２記載のガス化溶融炉ガスの利用方法。The method according to claim 2, wherein the pressure of the gasification and melting furnace gas is increased before mixing with the gas having a calorific value of 30 MJ / Nm3 or more. ガス化溶融炉ガスと３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスとの混合によって、コークス炉ガス相当の模擬コークス炉ガスとした後、該模擬コークス炉ガスを、コークス炉ガス配管へ接続することで、製鉄所内燃料として利用することを特徴とする請求項１乃至請求項３のいずれかに記載のガス化溶融炉ガスの利用方法。A simulated coke oven gas equivalent to a coke oven gas is obtained by mixing the gasification melting furnace gas and a gas having a calorific value of 30 MJ / Nm 3 or more, and the simulated coke oven gas is connected to a coke oven gas pipe. The method according to any one of claims 1 to 3, wherein the gas is used as fuel in an ironworks. ガス化溶融炉ガスを３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合する際に、混合後のガスの発熱量がＣＯＧ相当の１５〜２５ＭＪ／Ｎｍ３ となるように、混合量が調整されてなることを特徴とする請求項４記載のガス化溶融炉ガスの利用方法。When mixing the gasification melting furnace gas with a gas having a calorific value of 30 MJ / Nm 3 or more, the mixing amount is adjusted so that the calorific value of the mixed gas becomes 15 to 25 MJ / Nm 3 equivalent to COG. The method of using a gasification and melting furnace gas according to claim 4, wherein the gasification and melting furnace gas is used. ガス化溶融炉ガスを３０ＭＪ／Ｎｍ３ 以上の発熱量を保有するガスと混合する際に、混合後のガスの燃焼速度がＣＯＧ相当となるように、混合量が調整されてなることを特徴とする請求項４記載のガス化溶融炉ガスの利用方法。When the gasification melting furnace gas is mixed with a gas having a calorific value of 30 MJ / Nm 3 or more, the mixing amount is adjusted so that the combustion speed of the mixed gas becomes equivalent to COG. The method for utilizing the gasification and melting furnace gas according to claim 4.
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CN104745257A (en) * 2015-03-10 2015-07-01 华南理工大学 System and process for producing natural gas through combined supply of coal and coke-oven gas
CN104745257B (en) * 2015-03-10 2017-10-20 华南理工大学 A kind of system and technique of coal and oven gas alliance preparing natural gas
JP2018108540A (en) * 2016-12-28 2018-07-12 株式会社神鋼環境ソリューション Waste treatment system and waste treatment method

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