JP3806250B2 - Pulverized coal combustion equipment - Google Patents

Pulverized coal combustion equipment Download PDF

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JP3806250B2
JP3806250B2 JP19284098A JP19284098A JP3806250B2 JP 3806250 B2 JP3806250 B2 JP 3806250B2 JP 19284098 A JP19284098 A JP 19284098A JP 19284098 A JP19284098 A JP 19284098A JP 3806250 B2 JP3806250 B2 JP 3806250B2
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pulverized coal
air
coal
mixture
concentration
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JP2000028129A (en
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皓太郎 藤村
計二 武野
由則 小林
正治 大栗
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Mitsubishi Heavy Industries Ltd
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Mitsubishi Heavy Industries Ltd
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【０００１】
【発明の属する技術分野】
本発明は事業用、産業用ボイラ及び化学工業炉等に採用される微粉炭の燃焼装置に関するものである。
【０００２】
【従来の技術】
従来のこの種微粉炭燃焼装置について、図５に基づいて説明する。
【０００３】
０１はボイラ本体で、微粉炭ノズル２８、空気ノズル２９と共働するバーナ風箱０２を有し、炉内０３には過熱器、蒸発器、節炭器等に当たる伝熱管群０４を設置し、燃焼排ガス２４は同伝熱管群０４を加熱して煙道０５へと送られる。
【０００４】
煙道０５の途中には空気過熱器（ＡＨ）０６が配置され、煙道０５内の燃焼排ガス２４は誘引通風機（ＩＤＦ）０７で引かれて空気過熱器（ＡＨ）０６、灰捕集装置０８を経て煙突０９から大気に放出される。
【０００５】
なお、３０は炉底用再循環ガスラインで、煙道０５から分岐し、燃焼排ガス２４の一部を炉底用再循環ガス３２として炉底用再循環ガス送風機３１で送り、ボイラ本体０１の底部に供給する。
【０００６】
１８は燃焼用空気で、押込み通風機（ＦＤＦ）１０により引かれて、燃焼用空気ライン１１から主バーナ空気ライン１２を経由し、前記空気過熱器（ＡＨ）０６で加熱されて主バーナ燃焼用空気１９として前記バーナ風箱０２の空気ノズル２９から炉内０３内へ供給される。
【０００７】
また、燃焼用空気１８の一部は、燃焼用空気ライン１１から分岐して送風機１５により石炭粉砕用熱空気ライン１３へ送られ、前記空気過熱器（ＡＨ）０６で加熱されて石炭粉砕用熱空気２０として温調用冷空気２１と混合され、石炭粉砕機１４へ供給される。
【０００８】
石炭粉砕用熱空気２０は石炭粉砕機１４において、図示省略の外部設備から石炭供給ライン１６で供給される石炭２２と混合され、微粉炭混合気２３として微粉炭供給ライン１７から前記微粉炭ノズル２８へ供給される。
【０００９】
なお２７は温度調節装置で、微粉炭供給ライン１７の途中で微粉炭混合気２３の温度を計測し、石炭粉砕用熱空気ダンパ２５及び温調用冷空気ダンパ２６を制御して石炭粉砕用熱空気２０と温調用冷空気２１の混合を調節し、これにより微粉炭混合気２３の温度調節をおこなう。
【００１０】
前記の様に構成された従来の装置では、図示省略の石炭供給設備から送り込まれてきた石炭２２は石炭粉砕機１４へ投入され、別途送り込まれてきた石炭粉砕用熱空気２０によって乾燥されながら微粉化される。
【００１１】
石炭粉砕用熱空気２０は燃焼用空気ライン１１から一部を分流し、石炭粉砕用の送風機１５によって主バーナ燃焼用空気１９と同様に空気加熱器（ＡＨ）０６で加熱され、石炭粉砕機１４の出口温度が所定値となる様温調用冷空気２１と混合され、かつ調節されて石炭粉砕機１４へ供給される。
【００１２】
石炭粉砕機１４で微粉化された石炭２２は、石炭粉砕用熱空気２０と混合して微粉炭混合気２３を形成し、石炭粉砕機１４から微粉炭供給ライン１７を通しボイラ本体０１に設けられたバーナ風箱０２へ送り込まれる。
【００１３】
なお、バーナ風箱０２内には微粉炭混合気２３を炉内０３へ吹き込むための微粉炭ノズル２８と、それを燃焼するに必要な酸素を供給するための燃焼用空気１８を炉内０３へ吹き込む空気ノズル２９が設けられており、微粉炭混合気２３は微粉炭ノズル２８から炉内０３へ供給される。
【００１４】
他方、燃焼用空気１８は、大気を押込み通風機（ＦＤＦ）１０によって空気加熱器（ＡＨ）０６へ圧送し、別途空気加熱器（ＡＨ）０６へ送り込まれてくる燃焼排ガス２４と熱交換し、加熱された後、主バーナ燃焼用空気１９としてバーナ風箱０２へ送り込まれ空気ノズル２９から炉内０３へ吹き込まれる。
【００１５】
炉内０３へ投入された微粉炭混合気２３は図示省略の着火源によって着火し、前記空気ノズル２９から投入された主バーナ燃焼用空気１９によって炉内０３で燃焼を完結して燃焼排ガス２４が生成される。
【００１６】
燃焼排ガス２４は誘引通風機（ＩＤＦ）０７によって煙道０５を通して誘引され、伝熱管群０４を通過する際にその保有熱によって詳細図示省略の伝熱管群０４内の蒸気を加熱し、更に空気加熱器（ＡＨ）０６へ送り込まれて燃焼用空気１８を加熱した後、灰捕集装置０８を経て煙突０９から排出される。
【００１７】
なお、燃焼排ガス２４の一部は煙道０５から分岐し、炉底用再循環ガス３２として炉底用再循環ガス送風機３１により炉底用再循環ガスライン３０を通してボイラ本体０１底部から炉内０３へ供給し、伝熱管群０４の入口における燃焼排ガス２４温度の制御をおこなわせる。
【００１８】
【発明が解決しようとする課題】
前記した従来の燃焼装置においては、石炭粉砕用熱空気２０として大気（酸素濃度２１％）を使用しているため、石炭粉砕機１４内に可燃範囲ゾーンが形成され、何らかの原因により着火源が発生した場合には、石炭粉砕機１４内で火災発生の恐れがある。
【００１９】
また、微粉炭供給ライン１７内及び微粉炭ノズル２８内に微粉炭堆積が生じた場合、使用中（燃焼中）のバーナであれば先ず微粉炭ノズル２８内の堆積微粉炭に着火、スラッキングを起こして微粉炭ノズル２８及び微粉炭供給ライン１７の通風抵抗が増加するため、ラインの微粉炭堆積が助長され、遂には微粉炭ノズル２８及び微粉炭供給ライン１７の焼損に至る恐れが有る。
【００２０】
なお、これらの現象は、使用石炭の燃料比（固定炭素／揮発分）が低くなる程、その発生率も高くなる傾向にあるので、特に低燃料比炭の燃焼に当たっては、特別の安全対策を講じる必要がある。
【００２１】
本発明は前記した従来の燃焼装置における種々の不具合を解消し、石炭粉砕機内での火災発生を防止し、かつ、微粉炭ノズル及び微粉炭供給ライン等の焼損発生を防止し、安全操業を行って装置の安定化、長寿命化を確保するようにした微粉炭燃焼装置を提供することを課題とするものである。
【００２４】
【課題を解決するための手段】
本発明は前記した課題を解決すべくなされたものであり、バーナ風箱に微粉炭混合気を供給する微粉炭供給ラインにＯ2 濃度再調節器を設けると共に、主バーナ空気ラインから主バーナ燃焼用空気を分流した微粉炭混合気用添加空気をＯ2 濃度再調節器に供給する微粉炭混合気Ｏ2 再調節用空気ラインを設け、微粉炭混合気のＯ2 濃度を計測するＯ2 調節装置により微粉炭混合気用添加空気の流路を開閉制御して適正Ｏ2 微粉炭混合気の供給量を調節した微粉炭燃焼装置を提供するものである。
【００２５】
すなわち本発明によれば、微粉炭供給ラインに設けたＯ2 濃度再調節器を微粉炭混合気のＯ2 濃度が適正値を維持するように調節することにより、微粉炭供給ライン内に微粉炭堆積が生じた場合でも、不燃雰囲気を維持して石炭粉砕機及び微粉炭供給ラインにおける火災発生という不具合をなくしたものである。
【００２６】
【発明の実施の形態】
本発明の実施の一形態を図１乃至図４に基づいて説明する。
なお、前記した従来のものと同一部分には、図中同一の符号を付して示し、重複する説明は極力省略し、本実施の形態に固有の点に注力して説明する。
【００２７】
４４は石炭粉砕部Ｏ2 調節用ＧＲラインで（ＧＲ：GAS RECIRCULATION)、炉底用再循環ガスライン３０から分岐して石炭粉砕機１４の上流で石炭粉砕用熱空気ライン１３に連通し、炉底用再循環ガス３２の一部を石炭粉砕部Ｏ2 調節用ＧＲ３５として石炭粉砕用熱空気２０及び温調用冷空気２１に混合する径路を形成している。
【００２８】
なお、この径路にはＧＲ冷却器及び後述する石炭粉砕部Ｏ2 調節用ＧＲダンパ４６が設けられ、ＧＲ冷却器は石炭粉砕部Ｏ2 調節用ＧＲ３５中に含まれる水分を除去してＧＲ冷却器ドレン抜きライン３６から系外に排出し、また石炭粉砕部Ｏ2 調節用ＧＲダンパ４６は石炭粉砕部Ｏ2 調節用ＧＲライン４４を流れる石炭粉砕部Ｏ2 調節用ＧＲ３５の分量を制御してＯ2 濃度を調節する。
【００２９】
３３はＯ2 調節装置で、石炭粉砕機１４を出る微粉炭混合気２３をサンプリングして前記石炭粉砕部Ｏ2 調節用ＧＲダンパ４６の開度を制御して石炭粉砕機１４に入る段階からＯ2 濃度を調節する。
【００３０】
３９はＯ2 濃度再調節器で、微粉炭供給ライン１７から微粉炭ノズル２８に至る微粉炭混合気２３の径路に設けられ、同微粉炭供給ライン１７の微粉炭混合気２３と、主バーナ空気ライン１２から分岐した微粉炭混合気Ｏ2 再調節用空気ライン３８により微粉炭混合気用添加空気４０を導入し、微粉炭ノズル２８へ供給する適正Ｏ2 微粉炭混合気４１の濃度を調節する。
【００３１】
Ｏ2 濃度再調節器３９の詳細は図２〜図４に示す様に、微粉炭供給ライン１７から供給される微粉炭混合気２３から微粉炭混合気排気４２を分離して微粉炭混合気排気ライン４３から取出し、残部は微粉炭混合気Ｏ2 再調節用空気ライン３８から供給される微粉炭混合気用添加空気４０と混合して適正Ｏ2 微粉炭混合気４１として取り出す様に構成されている。
【００３２】
なお、微粉炭混合気排気４２は単独で又は主バーナ燃焼用空気１９と混合してバーナ風箱０２の空気ノズル２９から炉内０３内に供給される。
また、前記適正Ｏ2 微粉炭混合気４１はＯ2 調節装置３４でＯ2 濃度を計測され、微粉炭混合気Ｏ2 再調節用空気ライン３８に配設された微粉炭混合気Ｏ2 再調節ダンパ３７により微粉炭混合気用添加空気４０の量を制御され、適正Ｏ2 微粉炭混合気４１のＯ2 濃度を調節される。
【００３３】
本実施の形態は前記の様に構成されているので、微粉炭混合気２３の供給を受けて炉内０３で燃焼によって発生した燃焼排ガス２４の一部を煙道０５から分岐した炉底用再循環ガスライン３０より更に分岐して、石炭粉砕部Ｏ2 調節用ＧＲ３５として炉底用再循環ガスライン３０から分流し、十分にＧＲ冷却器４５によって含有水分を除去した後、石炭粉砕機１４入口へ送り込み別途送り込まれてくる石炭粉砕用熱空気２０及び温調用冷空気２１と混合する。
【００３４】
これらの３者、即ち石炭粉砕用熱空気２０、温調用冷空気２１、石炭粉砕部Ｏ2 調節用ＧＲ３５の混合は、石炭粉砕機１４出口の微粉炭混合気２３をサンプリングして、温度調節装置２７とＯ2 調節装置３３へ送り込み、所定の設定温度及び設定Ｏ2 濃度ととなる様石炭粉砕用熱空気２０、温調用冷空気２１及び石炭粉砕部Ｏ2 調節用ＧＲ３５の流量をそれぞれ石炭粉砕用熱空気ダンパ２５、温調用冷空気ダンパ２６、石炭粉砕部Ｏ2 調節用ＧＲダンパ４６で調節して行う。
【００３５】
石炭粉砕機１４出口における微粉炭混合気２３のＯ2 濃度は、燃料比が低く、揮発分が高い石炭程低い値に設定し、石炭粉砕機１４内及び微粉炭供給ライン１７内での炉内０３からの火炎伝播あるいは系内での自然発火等による焼損を未然に防止できる様にする。
【００３６】
しかし、低Ｏ2 濃度に調節された微粉炭混合気２３をそのままバーナ風箱０２へ送り込み微粉炭ノズル２８から炉内０３へ吹き込んで燃焼に供した場合は、着火不良及び燃焼不良となるのは明らかである。
【００３７】
そこで本実施形態では、微粉炭供給ライン１７にＯ2 濃度再調節器３９を設け、一旦低Ｏ2 濃度に設定した微粉炭混合気２３をバーナ風箱０２入口で再び燃焼に適した適正Ｏ2 微粉炭混合気４１としている。
【００３８】
図２、図３、及び図４にはＯ2 濃度再調節器３９の一例を示しているが、このＯ2 濃度再調節器３９に送り込まれてきた低Ｏ2 濃度の微粉炭混合気２３はＯ2 濃度再調節器３９内で遠心分離作用により、適正Ｏ2 微粉炭混合気４１と微粉炭混合気排気４２に分離される。
【００３９】
また、この適正Ｏ2 微粉炭混合気４１は、Ｏ2 濃度再調節器３９出口で主バーナ燃焼用空気１９から分離した微粉炭混合気用添加空気４０と混合する。
【００４０】
他方、微粉炭混合気排気４２はＯ2 濃度再調節器３９から微粉炭混合気排気ライン４３を通して主バーナ空気ライン１２へ合流させて炉内０３へ投入する（なお、ここで示した主バーナ空気ライン１２への合流に代えて、炉底用再循環ガスライン３０へ合流させることもある）。
【００４１】
微粉炭混合気用添加空気４０と微粉炭混合気排気４２の流量調節は、Ｏ2 濃度再調節器３９出口における微粉炭供給ライン１７のＯ2 濃度及び図示省略の混合気差圧（炉内０３圧との差圧）を常時計測し、適正Ｏ2 微粉炭混合気４１を所定Ｏ2 濃度で且つ一定混合気差圧となる様、Ｏ2 調節装置３４及び図示省略の混合気差圧調節装置によって、微粉炭混合気Ｏ2 再調節ダンパ３７及び微粉炭混合気排気量調節ダンパ４７を制御して行う。
【００４２】
なお、石炭粉砕機１４入口における石炭粉砕用熱空気２０と石炭粉砕部Ｏ2 調節用ＧＲ３５の混合割合は、石炭粉砕機１４出口の微粉炭混合気２３中のＯ2 濃度を１０％〜２１％の範囲で調節可能となる様に設定する。
【００４３】
また、適正Ｏ2 微粉炭混合気４１中のＯ2 濃度は常時１７％〜２１％となるようＯ2 濃度再調節器３９において微粉炭混合気用添加空気４０の量と微粉炭混合気排気４２の量を調節する。
【００４４】
この結果、低燃料比炭を使用時でも石炭粉砕機１４内に可燃範囲ゾーンが形成される事もなく、また、微粉炭供給ライン１７内も微粉炭堆積が生じた場合でも不燃雰囲気に維持されているので、石炭粉砕機１４及び微粉炭供給ライン１７における火災発生に配慮することもなくボイラの運転に専念できる。
【００４５】
以上、本発明を図示の実施の形態について説明したが、本発明はかかる実施の形態に限定されず、本発明の範囲内でその具体的構造に種々の変更を加えてよいことはいうまでもない。
【００４７】
【発明の効果】
以上、本発明によれば、バーナ風箱に微粉炭混合気を供給する微粉炭供給ラインにＯ2 濃度再調節器を設けると共に、主バーナ空気ラインから主バーナ燃焼用空気を分流した微粉炭混合気用添加空気をＯ2 濃度再調節器に供給する微粉炭混合気Ｏ2 再調節用空気ラインを設け、微粉炭混合気のＯ2 濃度を計測するＯ2 調節装置により微粉炭混合気用添加空気の流路を開閉制御して適正Ｏ2 微粉炭混合気の供給量を調節する様にして微粉炭燃焼装置を構成したので、微粉炭供給ラインに設けたＯ2 濃度再調節器を微粉炭混合気のＯ2 濃度が適正値を維持するように調節することにより、微粉炭供給ライン内に微粉炭堆積が生じた場合でも、不燃雰囲気を維持して石炭粉砕機及び微粉炭供給ラインにおける火災発生という不具合をなくし、安全操業を確保して信頼性を高め、かつ、保守点検に要する時間、経費を節減して経済性を高めた微粉炭燃焼装置を得ることができたものである。
【図面の簡単な説明】
【図１】本発明の実施の一形態に係る微粉炭燃焼装置の系統図である。
【図２】図１のII部の詳細構造を示す拡大図である。
【図３】図２のＡ−Ａ断面図である。
【図４】図２のＢ−Ｂ断面図である。
【図５】従来の微粉炭燃焼装置の系統図である。
【符号の説明】
０１ ボイラ本体
０２ バーナ風箱
０３ 炉内
０４ 伝熱管群
０５ 煙道
０６ 空気加熱器空気過熱器
０７ 誘引通風機
０８ 灰捕集装置
０９ 煙突
１０ 押込み通風機
１１ 燃焼用空気ライン
１２ 主バーナ空気ライン
１３ 石炭粉砕用熱空気ライン
１４ 石炭粉砕機
１５ 送風機
１６ 石炭供給ライン
１７ 微粉炭供給ライン
１８ 燃焼用空気
１９ 主バーナ燃焼用空気
２０ 石炭粉砕用熱空気
２１ 温調用冷空気
２２ 石炭
２３ 微粉炭混合気
２４ 燃焼排ガス
２５ 石炭粉砕用熱空気ダンパ
２６ 温調用冷空気ダンパ
２７ 温度調節装置
２８ 微粉炭ノズル
２９ 空気ノズル
３０ 炉底用再循環ガスライン
３１ 炉底用再循環ガス送風機
３２ 炉底用再循環ガス
３３ Ｏ2 調節装置
３４ Ｏ2 調節装置
３５ 石炭粉砕部Ｏ2 調節用ＧＲ
３６ ＧＲ冷却器ドレン抜きライン
３７ 微粉炭混合気Ｏ2 再調節ダンパ
３８ 微粉炭混合気Ｏ2 再調節用空気ライン
３９ Ｏ2 濃度再調節器
４０ 微粉炭混合気用添加空気
４１ 適正Ｏ2 微粉炭混合気
４２ 微粉炭混合気排気
４３ 微粉炭混合気排気ライン
４４ 石炭粉砕部Ｏ2 調節用ＧＲライン
４５ ＧＲ冷却器
４６ 石炭粉砕部Ｏ2 調節用ＧＲダンパ
４７ 微粉炭混合気排気量調節ダンパ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion apparatus for pulverized coal employed in business, industrial boilers, chemical industrial furnaces and the like.
[0002]
[Prior art]
This conventional pulverized coal combustion apparatus will be described with reference to FIG.
[0003]
01 is a boiler body, has a burner wind box 02 that cooperates with a pulverized coal nozzle 28 and an air nozzle 29, and a heat transfer tube group 04 corresponding to a superheater, an evaporator, a economizer, etc. is installed in the furnace 03, The combustion exhaust gas 24 heats the heat transfer tube group 04 and is sent to the flue 05.
[0004]
An air superheater (AH) 06 is arranged in the middle of the flue 05, and the combustion exhaust gas 24 in the flue 05 is drawn by an induction fan (IDF) 07, and the air superheater (AH) 06, an ash collector. After 08, it is emitted from the chimney 09 to the atmosphere.
[0005]
Reference numeral 30 denotes a furnace bottom recirculation gas line which branches from the flue 05 and sends a part of the combustion exhaust gas 24 as a furnace bottom recirculation gas 32 by the furnace bottom recirculation gas blower 31, Feed to the bottom.
[0006]
Reference numeral 18 denotes combustion air which is drawn by a forced air blower (FDF) 10 and is heated from the combustion air line 11 via the main burner air line 12 by the air superheater (AH) 06 to be used for main burner combustion. Air 19 is supplied from the air nozzle 29 of the burner wind box 02 into the furnace 03.
[0007]
Further, a part of the combustion air 18 is branched from the combustion air line 11 and sent to the coal pulverization hot air line 13 by the blower 15, and is heated by the air superheater (AH) 06 to heat the coal pulverization heat. Air 20 is mixed with temperature-controlled cold air 21 and supplied to the coal pulverizer 14.
[0008]
Coal pulverization hot air 20 is mixed in a coal pulverizer 14 with coal 22 supplied from an external facility (not shown) through a coal supply line 16 to form a pulverized coal mixture 23 from the pulverized coal supply line 17 to the pulverized coal nozzle 28. Supplied to.
[0009]
A temperature adjusting device 27 measures the temperature of the pulverized coal mixture 23 in the middle of the pulverized coal supply line 17 and controls the coal pulverizing hot air damper 25 and the temperature adjusting cold air damper 26 so as to pulverize the coal pulverizing hot air. The temperature of the pulverized coal mixture 23 is adjusted by adjusting the mixing of the temperature 20 and the temperature-controlled cold air 21.
[0010]
In the conventional apparatus configured as described above, the coal 22 fed from a coal supply facility (not shown) is fed into the coal pulverizer 14 and is finely powdered while being dried by the hot air 20 for coal pulverization that has been separately fed. It becomes.
[0011]
A portion of the hot air 20 for coal pulverization is diverted from the combustion air line 11 and is heated by an air heater (AH) 06 in the same manner as the main burner combustion air 19 by a blower 15 for coal pulverization. Is mixed with the temperature adjusting cold air 21 so that the outlet temperature becomes a predetermined value, adjusted and supplied to the coal pulverizer 14.
[0012]
Coal 22 pulverized by the coal pulverizer 14 is mixed with hot air 20 for pulverizing coal to form a pulverized coal mixture 23, which is provided in the boiler body 01 through the pulverized coal supply line 17 from the coal pulverizer 14. It is sent to the burner-style box 02.
[0013]
In the burner wind box 02, a pulverized coal nozzle 28 for blowing the pulverized coal mixture 23 into the furnace 03 and a combustion air 18 for supplying oxygen necessary for burning the pulverized coal mixture 23 into the furnace 03 are provided. An air nozzle 29 for blowing is provided, and the pulverized coal mixture 23 is supplied from the pulverized coal nozzle 28 into the furnace 03.
[0014]
On the other hand, the combustion air 18 is pressure-fed to the air heater (AH) 06 by the forced air blower (FDF) 10, and exchanges heat with the combustion exhaust gas 24 separately sent to the air heater (AH) 06. After being heated, the main burner combustion air 19 is sent to the burner wind box 02 and blown into the furnace 03 from the air nozzle 29.
[0015]
The pulverized coal mixture 23 introduced into the furnace 03 is ignited by an ignition source (not shown), and combustion is completed in the furnace 03 by the main burner combustion air 19 introduced from the air nozzle 29, and the combustion exhaust gas 24. Is generated.
[0016]
The combustion exhaust gas 24 is attracted through the flue 05 by an induction fan (IDF) 07, and when passing through the heat transfer tube group 04, the heat in the heat transfer tube group 04 (not shown in detail) is heated by the retained heat, and further air heating After being sent to the vessel (AH) 06 to heat the combustion air 18, it is discharged from the chimney 09 through the ash collector 08.
[0017]
A part of the combustion exhaust gas 24 branches off from the flue 05 and is passed through the furnace bottom recirculation gas line 30 by the furnace bottom recirculation gas blower 31 as the furnace bottom recirculation gas 32 from the bottom of the boiler body 01 to the furnace 03. The temperature of the combustion exhaust gas 24 at the inlet of the heat transfer tube group 04 is controlled.
[0018]
[Problems to be solved by the invention]
In the conventional combustion apparatus described above, since the atmosphere (oxygen concentration 21%) is used as the hot air 20 for pulverizing coal, a combustible range zone is formed in the coal pulverizer 14, and an ignition source is generated for some reason. If it occurs, a fire may occur in the coal pulverizer 14.
[0019]
Further, when pulverized coal accumulation occurs in the pulverized coal supply line 17 and in the pulverized coal nozzle 28, first, if the burner is in use (combusting), the deposited pulverized coal in the pulverized coal nozzle 28 is first ignited and slacked. As a result, the ventilation resistance of the pulverized coal nozzle 28 and the pulverized coal supply line 17 increases, so that the accumulation of pulverized coal in the line is promoted, and there is a risk that the pulverized coal nozzle 28 and the pulverized coal supply line 17 will eventually be burned.
[0020]
These phenomena tend to increase the lower the fuel ratio (fixed carbon / volatile content) of the coal used, so special safety measures should be taken, especially when burning low-fuel ratio coal. It is necessary to take.
[0021]
The present invention eliminates various problems in the conventional combustion apparatus described above, prevents the occurrence of fire in the coal pulverizer, prevents the occurrence of burning of the pulverized coal nozzle and the pulverized coal supply line, etc., and performs safe operation. Therefore, it is an object of the present invention to provide a pulverized coal combustion apparatus that ensures stabilization of the apparatus and a longer life.
[0024]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problems, and is provided with an O 2 concentration readjustment device in a pulverized coal supply line for supplying a pulverized coal mixture to a burner wind box, and main burner combustion from the main burner air line. diverts use air and the pulverized coal mixture additives air provided pulverized coal mixture O 2 readjust air line for supplying the O 2 concentration readjusting device, O 2 adjusted for measuring the O 2 concentration of the pulverized coal-air mixture The present invention provides a pulverized coal combustion apparatus in which the flow rate of the additive air for the pulverized coal mixture is controlled by the apparatus to adjust the supply amount of the appropriate O 2 pulverized coal mixture.
[0025]
That is, according to the present invention, by adjusting the O 2 concentration readjusting device provided in the pulverized coal supply line, as the O 2 concentration of the pulverized coal-air mixture to maintain a proper value, pulverized coal in the pulverized coal supply line Even if deposition occurs, the incombustible atmosphere is maintained and the problem of fire occurrence in the coal pulverizer and pulverized coal supply line is eliminated.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
The same parts as those of the conventional one are denoted by the same reference numerals in the drawings, and redundant description will be omitted as much as possible, and the description will focus on points unique to the present embodiment.
[0027]
44 is a GR line for adjusting the coal crushing section O 2 (GR: GAS RECIRCULATION), branched from the recirculation gas line 30 for the bottom of the furnace, and communicated with the hot air line 13 for coal crushing upstream of the coal crusher 14. A part of the bottom recirculation gas 32 is mixed with the coal crushing hot air 20 and the temperature adjusting cold air 21 as a coal crushing part O 2 adjusting GR 35.
[0028]
In addition, a GR cooler and a later-described coal damper O 2 adjusting GR damper 46 are provided in this path, and the GR cooler removes moisture contained in the coal grinder O 2 adjusting GR 35 to remove the GR cooler. The draining line 36 discharges the system outside, and the coal pulverizing part O 2 adjusting GR damper 46 controls the amount of the coal pulverizing part O 2 adjusting GR 35 flowing through the coal pulverizing part O 2 adjusting GR line 44 to 2 Adjust the concentration.
[0029]
Reference numeral 33 denotes an O 2 adjusting device which samples the pulverized coal mixture 23 exiting the coal pulverizer 14 and controls the opening degree of the GR damper 46 for adjusting the coal pulverizing section O 2 to enter the coal pulverizer 14 from the stage. 2 Adjust the concentration.
[0030]
39 is an O 2 concentration readjustment device, provided in the path of the pulverized coal mixture 23 from the pulverized coal supply line 17 to the pulverized coal nozzle 28, and the pulverized coal mixture 23 of the pulverized coal supply line 17 and the main burner air introducing pulverized coal mixture additives air 40 by the pulverized coal mixture O 2 readjust air line 38 which is branched from the line 12, adjusting the concentration of the appropriate O 2 pulverized coal mixture 41 supplied to the pulverized coal nozzle 28 .
[0031]
As shown in FIGS. 2 to 4, the details of the O 2 concentration readjustment device 39 are obtained by separating the pulverized coal mixture exhaust 42 from the pulverized coal mixture 23 supplied from the pulverized coal supply line 17 and pulverized coal mixture exhaust. It is taken out from the line 43 and the remainder is configured to be mixed with the pulverized coal mixture added air 40 supplied from the pulverized coal mixture O 2 reconditioning air line 38 and taken out as an appropriate O 2 pulverized coal mixture 41. Yes.
[0032]
The pulverized coal mixture exhaust 42 is supplied alone or mixed with the main burner combustion air 19 and supplied from the air nozzle 29 of the burner wind box 02 into the furnace 03.
Further, the appropriate O 2 pulverized coal mixture 41 is measured for O 2 concentration by an O 2 adjusting device 34, and the pulverized coal mixture O 2 readjusted disposed in the air line 38 for pulverized coal mixture O 2 readjustment. The amount of the added air 40 for the pulverized coal mixture is controlled by the damper 37, and the O 2 concentration of the appropriate O 2 pulverized coal mixture 41 is adjusted.
[0033]
Since the present embodiment is configured as described above, a part of the flue gas 24 generated by the combustion in the furnace 03 upon receiving the supply of the pulverized coal mixture 23 is branched from the flue 05 and regenerated for the bottom of the furnace. Further branched from the circulating gas line 30, diverted from the furnace bottom recirculation gas line 30 as a coal pulverizing section O 2 adjustment GR 35, and after sufficiently removing moisture contained by the GR cooler 45, the coal pulverizer 14 inlet And mixed with hot air 20 for coal pulverization and cold air 21 for temperature control, which are separately fed.
[0034]
These three components, namely, coal pulverizing hot air 20, temperature adjusting cold air 21, and coal pulverizing section O 2 adjusting GR 35 are sampled from the pulverized coal mixture 23 at the outlet of the coal pulverizing machine 14, and the temperature adjusting device is sampled. 27 and the O 2 adjusting device 33, and the coal pulverizing flow rate of the coal pulverizing hot air 20, the temperature adjusting cold air 21 and the coal pulverizing portion O 2 adjusting GR 35 is set to a predetermined set temperature and set O 2 concentration. The hot air damper 25 for adjusting the temperature, the cold air damper 26 for adjusting the temperature, and the GR damper 46 for adjusting the coal crushing portion O 2 are used for adjustment.
[0035]
The O 2 concentration of the pulverized coal mixture 23 at the outlet of the coal pulverizer 14 is set to a lower value as the coal has a lower fuel ratio and a higher volatile content, and the inside of the furnace in the coal pulverizer 14 and the pulverized coal supply line 17 is set. It is possible to prevent the flame from burning from 03 or burning due to spontaneous ignition in the system.
[0036]
However, when the pulverized coal mixture 23 adjusted to a low O 2 concentration is sent directly to the burner-like box 02 and blown into the furnace 03 from the pulverized coal nozzle 28 and used for combustion, the ignition failure and the combustion failure are caused. it is obvious.
[0037]
Therefore, in the present embodiment, the pulverized coal supply line 17 is provided with the O 2 concentration readjustment device 39, and the pulverized coal mixture 23 once set to the low O 2 concentration is re-appropriated for the appropriate O 2 suitable for combustion at the inlet of the burner wind box 02. A pulverized coal mixture 41 is used.
[0038]
2, 3, and in FIG. 4 shows an example of the O 2 concentration readjusting device 39, the O 2 concentration readjusting device of a low O 2 concentrations have sent is in the 39 pulverized coal mixture 23 By the centrifugal separation action in the O 2 concentration readjustment device 39, the O 2 pulverized coal mixture 41 and the pulverized coal mixture exhaust gas 42 are separated.
[0039]
Further, the appropriate O 2 pulverized coal mixture 41 is mixed with the pulverized coal mixture added air 40 separated from the main burner combustion air 19 at the outlet of the O 2 concentration re-regulator 39.
[0040]
On the other hand, the pulverized coal mixture exhaust gas 42 is merged from the O 2 concentration re-regulator 39 through the pulverized coal mixture exhaust line 43 to the main burner air line 12 and introduced into the furnace 03 (the main burner air shown here). Instead of merging into the line 12, it may be merged into the furnace bottom recirculation gas line 30).
[0041]
Flow rate regulation of the pulverized coal mixture additives air 40 and the pulverized coal mixture exhaust 42, O 2 mixture differential pressure of the O 2 concentration and not shown in the concentration readjustment 39 pulverized coal feed line 17 at the outlet (the furnace 03 measuring the differential pressure) between the pressure at all times, the proper O 2 to the pulverized coal-air mixture 41 predetermined O 2 concentration and a constant mixture pressure difference to become like, O 2 adjustment device 34 and the air-fuel mixture differential pressure regulator (not shown) Thus, the pulverized coal mixture O 2 readjustment damper 37 and the pulverized coal mixture exhaust amount adjustment damper 47 are controlled.
[0042]
The mixing ratio of the coal pulverizing hot air 20 and the coal pulverizing section O 2 adjusting GR 35 at the coal pulverizer 14 inlet is 10% to 21% of the O 2 concentration in the pulverized coal mixture 23 at the coal pulverizer 14 outlet. Set to be adjustable within the range.
[0043]
Also, appropriate O 2 pulverized coal O 2 concentration of the mixture in the 41 amount and pulverized coal mixture exhaust pulverized coal mixture additives air 40 in the O 2 concentration readjusted 39 so as to be always 17% to 21% 42 Adjust the amount.
[0044]
As a result, a combustible range zone is not formed in the coal pulverizer 14 even when low fuel specific coal is used, and the pulverized coal supply line 17 is maintained in an incombustible atmosphere even when pulverized coal accumulation occurs. Therefore, it is possible to concentrate on the operation of the boiler without considering the fire occurrence in the coal pulverizer 14 and the pulverized coal supply line 17.
[0045]
Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to this embodiment, and it goes without saying that various modifications may be made to the specific structure within the scope of the present invention. Absent.
[0047]
【The invention's effect】
As described above, according to the present invention, the pulverized coal mixture in which the O 2 concentration readjustment device is provided in the pulverized coal supply line for supplying the pulverized coal mixture to the burner wind box and the main burner combustion air is divided from the main burner air line. Add pulverized coal mixture O 2 readjustment air line for supplying air additive air to O 2 concentration readjustment device, and add pulverized coal mixture by O 2 adjustment device that measures O 2 concentration of pulverized coal mixture Since the pulverized coal combustion device was configured to control the supply of the appropriate O 2 pulverized coal mixture by opening and closing the air flow path, the O 2 concentration readjuster provided in the pulverized coal supply line was replaced with pulverized coal. by the O 2 concentration of the mixture is adjusted to maintain the proper value, even if the pulverized coal deposits has occurred in the pulverized coal supply line, a fire in the coal pulverizer and pulverized coal supply line to maintain the incombustible atmosphere to eliminate the problem that occurs, the probability of the safety operation It was possible to obtain a pulverized coal combustion apparatus with improved reliability by reducing the time and cost required for maintenance inspection and improving the economy.
[Brief description of the drawings]
FIG. 1 is a system diagram of a pulverized coal combustion apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged view showing a detailed structure of a portion II in FIG.
3 is a cross-sectional view taken along the line AA in FIG.
4 is a cross-sectional view taken along the line BB in FIG.
FIG. 5 is a system diagram of a conventional pulverized coal combustion apparatus.
[Explanation of symbols]
01 Boiler body 02 Burner wind box 03 Furnace 04 Heat transfer tube group 05 Flue 06 Air heater Air superheater 07 Induction fan 08 Ash collector 09 Chimney 10 Pusher 11 Combustion air line 12 Main burner air line 13 Coal pulverization hot air line 14 Coal pulverizer 15 Blower 16 Coal supply line 17 Pulverized coal supply line 18 Combustion air 19 Main burner combustion air 20 Coal pulverization hot air 21 Temperature control cold air 22 Coal 23 Pulverized coal mixture 24 Combustion exhaust gas 25 Coal pulverization hot air damper 26 Temperature control cold air damper 27 Temperature control device 28 Pulverized coal nozzle 29 Air nozzle 30 Recirculation gas line for furnace bottom 31 Recirculation gas blower for furnace bottom 32 Recirculation gas for furnace bottom 33 O 2 adjuster 34 O 2 adjuster 35 Coal crushing part O 2 adjustment GR
36 GR cooler drain line 37 pulverized coal mixture O 2 readjustment damper 38 pulverized coal mixture O 2 readjustment air line 39 O 2 concentration readjuster 40 pulverized coal mixture added air 41 appropriate O 2 pulverized coal Mixture 42 Pulverized Coal Mixture Exhaust 43 Pulverized Coal Mixture Exhaust Line 44 Coal Crushing Part O 2 Adjustment GR Line 45 GR Cooler 46 Coal Crushing Part O 2 Adjustment GR Damper 47 Dust Coal Mixture Exhaust Amount Adjustment Damper

Claims (1)

バーナ風箱に微粉炭混合気を供給する微粉炭供給ラインにＯ2 濃度再調節器を設けると共に、主バーナ空気ラインから主バーナ燃焼用空気を分流した微粉炭混合気用添加空気をＯ2 濃度再調節器に供給する微粉炭混合気Ｏ2 再調節用空気ラインを設け、微粉炭混合気のＯ2 濃度を計測するＯ2 調節装置により微粉炭混合気用添加空気の流路を開閉制御して適正Ｏ2 微粉炭混合気の供給量を調節したことを特徴とする微粉炭燃焼装置。A pulverized coal supply line that supplies the pulverized coal mixture to the burner wind box is provided with an O 2 concentration readjustment device, and the added air for the pulverized coal mixture obtained by diverting the main burner combustion air from the main burner air line is used as the O 2 concentration. the pulverized coal mixture O 2 readjust air line for supplying the readjustment device is provided, O 2 adjustment device the flow path of the added air pulverized coal mixture off controlled by measuring the O 2 concentration of the pulverized coal-air mixture A pulverized coal combustion apparatus characterized in that the supply amount of an appropriate O 2 pulverized coal mixture is adjusted.
JP19284098A 1998-07-08 1998-07-08 Pulverized coal combustion equipment Expired - Fee Related JP3806250B2 (en)

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JP5385853B2 (en) * 2010-05-18 2014-01-08 株式会社神戸製鋼所 Crusher ignition prevention method and ignition prevention device
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CN102893090B (en) * 2010-05-17 2015-04-15 株式会社神户制钢所 Ignition prevention method and ignition prevention apparatus for crusher
CN102418916A (en) * 2011-12-06 2012-04-18 山西蓝天环保设备有限公司 Oil field gas injection boiler taking pulverized coal as fuel

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