JP3809981B2 - Intelligent soot blower controller for coal fired boiler facilities - Google Patents

Description

Ｗｍ：メタル質量（Ｋｇ）
Ｃｍ：メタル比熱（Ｋｃａｌ／Ｋｇ°Ｃ）
Ｃｆ：流体比熱（Ｋｃａｌ／Ｋｇ°Ｃ）
Ｖｐ：流体容積（ｍ³）
Ｖ ：流体比容積（ｍ³／Ｋｇ）
前記（１’）式は伝熱面に対して、
出口流体熱量＋伝熱面蓄熱量＝入口流体熱量＋ガス系の失った熱量
の関係が成り立つので、これを表す次式により展開できる。
【００２４】
Ｆ×Ｈｏ＋ｄｑｔ／ｄｔ＝Ｆ×Ｈｉ＋Ｑ （１”）
ｑｔ：一時的な蓄熱量（Ｋｃａｌ／ｓ）
また、蒸発器設置のボイラにおいて、蒸発器の吸熱量は水系より求めることができないので、次のガス系のエネルギーバランス式により算出する。
【００２５】
Ｑ＝（ｔｇｉ−ｔｇｏ）×Ｃｇ×Ｗｇ
ｔｇｉ：入口ガス温度（°Ｃ）
ｔｇｏ：出口ガス温度（°Ｃ）
Ｃｇ ：ガス比熱（Ｋｃａｌ／Ｋｇ°Ｃ）
Ｗｇ ：ガス量（Ｋｇ／ｓ）
次に、トータルガス量１５と各バンク部吸熱量１８から各バンク部出入口の管外のガス温度を計算する。管外のガス側各部温度の算出は、（１）式で求めた水系の吸熱量を使用して、エネルギーバランス式により算出する。
【００２６】
つまり、節炭器（Ｅｃｏ）出口ガス温度が判明していれば（当該ガス温度を実測すれば）、（２）式により節炭器入口ガス温度を得ることができる。
【００２７】
このようにガス上流側の伝熱面について順次同様な計算をすることで、最終的には、火炉出口ガス温度２０まで求めることができる。
【００２８】
ｔｇｉ＝ｔｇｏ＋｛Ｑ／（Ｃｐｇ・Ｗｇ）｝ ……………（２）
ここで、ｔｇ ：ガス温度（節炭器出口ガス温度から（２）式により各部入口ガス温度を順次算出）
Ｑ ：吸熱量 （（１）式より算出） （Ｋｃａｌ／ｓ）
Ｃｐｇ：ガス比熱（ガス温度より算出） （Ｋｃａｌ／ｋｇ℃）
Ｗｇ ：ガス量 （計算） （ｋｇ／ｓ）
石炭焚きボイラの火炉の設計条件である火炉に対する有効熱量（輻射源となる有効面積）２１と火炉出口ガス温度２０との関係から現状の火炉有効面積２２を知ることができる。端的に言えば、火炉出口ガス温度２０が設計条件よりも上昇していれば、汚れが進行していることを示している。
【００２９】
そして、（３）式に示すように、現状の有効火炉面積と構造面積（設計火炉有効面積）の比から火炉伝熱面汚れ度２４を推定することができる。
【００３０】
火炉汚れ度ｄｆ＝設計有効火炉面積／現状有効火炉面積 ……（３）
また、バンク部の伝熱面汚れ度については、伝熱面の熱貫流率に基づいて決めることとなる。
【００３１】
ここで、現状熱貫流率２５は、
Ｑ＝Ｋ・Ａ・Δｔ………………（４）
により計算する。
【００３２】
ここで、Ｑ：吸熱量（１）式より計算
Ａ：伝熱面積（設計値）
Δｔ：対数平均温度差
基準熱貫流率２６は、
Ｋｏ＝（Ｕｃｇ＋Ｕｒｇ）×Ｕｃｓ／（Ｕｃｇ＋Ｕｒｇ＋Ｕｃｓ）…（５）
ここで、Ｕｃｇ：ガス側対流熱伝達率（ガス量、ガス温度より計算）
Ｕｒｇ：ガス側輻射熱伝達率（ガス温度より計算）
Ｕｃｓ：水蒸気側対流熱伝達率（蒸気流量、蒸気温度より計算）
により計算する。
【００３３】
そして、（６）式に示すように、現状熱貫流率と基準熱貫流率の比から各バンク部伝熱面汚れ度２７を推定することができる。
【００３４】
各バンク部伝熱面汚れ度ｄｆ＝基準熱貫流率／現状熱貫流率 ……（６）
最適起動伝熱面決定処理手段２では、図３に示すように、（３）式で求めた火炉汚れ度２４や（６）式で求めた各バンク部伝熱面汚れ度２７等のメンバシップ関数３４，３５およびルール（起動側及び抑止側）３３，３７，４１，４３からＭＩＮ演算４６とＭＡＸ演算４７のファジィ推論を実施し、起動要求度（−１〜０〜＋１）５０を算出する。
【００３５】
メンバシップ関数は汚れ度３４，３５以外に静的なボイラ運転状態３８，３９、動的なボイラ運転状態、前回起動からの経過時間４４，４５により定義する。
【００３６】
起動要求のメンバシップ関数３５，３９，４５は、スートブロワの起動要求を−１．０〜０〜＋１．０（低い〜高い）の数値により表現したメンバシップ関数を考える。この場合、正側（０．０〜＋１．０）を高い領域、負側（−１．０〜０．０）を低い領域とする。
【００３７】
また、ルール３３，３７，４３は、図３に示すように、

が、一つのルールとなる。仮定部分６０には汚れ度やボイラ状態などの全てのメンバシップ関数を定義できるが、結論部分６１にはスートブロアの「起動要求」のメンバシップ関数を定義する。
【００３８】
さらに、仮定部分６０には複数のメンバシップ関数も定義することが出来る。
【００３９】
また、ルールにはスートブロアについての起動側ルール群３０と抑止側ルール群３１とに分割され、結論部３５，３９，４５の起動要求が高い（正側）ルールの集まりを起動側ルール群３０といい、反対に起動要求が低い（負側）ルールの集まりを抑止側ルール群３１とする。
【００４０】
まず、ルール単位の結論すなわちＭＩＮ演算４６を行う。本演算は、例えば、図３の▲１▼の伝熱面汚れ度ルール例３２において、仮定部６０の「火炉汚れ度が大」のメンバシップ関数３４で火炉汚れ度が１．１２の場合、縦軸の高さは０．３となる。次に、結論部６１の「火炉起動要求度が高い」６１のメンバシップ関数３５の縦軸の高さが０．３以下の部分（すなわち○ａ部）の面積を伝熱面汚れ度ルール例３２のルール単位の結論という。
【００４１】
同様に、図３の▲２▼のボイラ状態（静的）ルール例３６において火炉出口ガス温度偏差が＋２３℃の場合の結論は○ｂ部となる。同様に図３に示す抑止側ルール群についても各ルール単位の結論を求める（スートブロアを起動するルールとして例えば▲４▼に示すように、前回のスートブロア起動後どれぐらい時間が経過しているかというルールもある）。
【００４２】
全ルールについて算出した結論の高さ方向についてＭＡＸ演算４７により、最大の面積値を選択し、図３に示す○ｃ部が全体のルールの結論となる（○ｃ部を含む台形形状のハッチング部がスートブロアする領域を示し、その左側の台形形状のハッチング部がスートブロアしない領域を示す）。
【００４３】
起動要求度５０は、算出した結論について重心の計算４９を計算し、起動要求度５０とする。
【００４４】
前述の処理により最適起動箇所の決定５１においては、各スートブロワグループの起動要求度５０の中で、最大値（同一の場合はガス上流側優先）を計算し、その値が一定値（例えば＋０．５）を越えた場合にそのグループを最適とみなし起動をかける。
【００４５】
以上のような、メンバシップ関数を定義し、ＭＩＮ演算およびＭＡＸ演算を行うようなことは従来知られている手法であり、本発明においてもこの手法を利用している。
【００４６】
最適起動伝熱面箇所の決定５１では、スートブロワの起動の判定は、図６に示す位置に取り付けられたスートブロアについて、図４に示すように、ボイラの伝熱面単位６１で行い、スートブロワが完了した時点で、次に運用する必要のある伝熱面の判断を行う。
【００４７】
ここで、図４は、スートブロアの伝熱面区分と順序を示す図であり、輻射伝熱部である火炉の伝熱面名称のＦ’ＣＥは、ファーネスを表している。スートブロアの取付位置については、石炭の燃焼による溶融灰が火炉壁や過熱器、再熱器に付着する度合い（一般的な評価法としては、灰塩基性／酸性比と灰溶融温度を石炭灰の特性に応じて使い分ける）を考慮し、石炭焚きボイラの実績等を踏まえ、ガス温度と噴射有効範囲の関係から、図６に示す設置例のようにボイラスートブロアのアレンジメントを決定している。特に、火炉壁においては、灰付着が高いと予想される最上段バーナ近傍へスートブロアを集中配置している。図７は連続起動スートブロア台数を示す図である。
【００４８】
そして、対流伝熱部である火炉部後流のバンク部の伝熱面は８個に区分されていて、Ｐー２ＳＨはペンダント（吊り下げ）の２次過熱器（Ｓｕｐｅｒ Ｈｅａｔｅｒ）であり、Ｈー１ＲＨはホリゾンタル（水平）の１次再熱器（Ｒｅｈｅａｔｅｒ）をそれぞれ表している。図４に記載のスートブロア順序における符号Ｆ、Ｂ、Ｒ、ＬはそれぞれＦｒｏｎｔ、Ｂａｃｋ、Ｒｉｇｈｔ、Ｌｅｆｔを表す。
【００４９】
いずれか伝熱面の起動条件が成立すると、図４に示すように、その伝熱面内で起動順序を火炉上段→下段の順に缶前後、左右スートブロワに配分して火炉用で対向するスートブロワを起動させるように、予め火炉スートブロワの設置場所と伝熱管との関係を整理しておき、火炉メタル温度の上昇原因となる同一伝熱管上のスートブロワ起動影響を極力廃した起動スケジュールとなる組み合わせを設定し、この時出来る限り火炉内の熱負荷バランスも考慮に入れたスートブロワ起動スケジュールを設定して予め決定しておき、スートブロワ起動処理（１）手段３において、その登録された伝熱面内スートブロワ順序６２および起動ペア数６３に従い（図４によれば、例えば火炉のスートブロアの総数は１６ペア存在するが、１回の起動で１６ペア全部をブロアするのではなくて、数ペアだけスートブロアするというように設計している。１回の起動でブロアするペア数は図７に示されている。）、前回終了した次のスートブロワより起動される。
【００５０】
ここで、１回の起動における起動ペア数を決めるための決め方について以下述べる。火炉、過熱器、再熱器の汚れの進行の速い石炭において、前記（３）式と（６）式の定義から、汚れていない状態で１．０であり、汚れが進行すると汚れ度は大きな値となる。そして、スートブロアの起動台数としては、各ボイラ負荷帯毎に規定のスートブロア台数を起動したときの汚れ度の最小値が約１．２以下（有効伝熱面積の８０％程度）となる値を目標とすると共に、各ボイラ負荷帯で同一本数では、低負荷帯になるほど火炉における熱吸収割合が大きくなるため、逆にブロアのし過ぎとなって伝熱特性に外乱を与えるため、１回の起動による汚れの落ち具合と伝熱特性に与える影響を考慮して起動ペア数を決定する。
【００５１】
ただし、スートブロワ起動処理（１）手段３では、起動しようとするスートブロワが自動モードでなく、手動モードである場合は、スキップして次のペアのスートブロワに起動要求がかかり、前述したように予め決めている起動ペア数分起動して終了またはスキップし続けて一巡すれば、当該伝熱面スートブロワ起動は終了となるが、この時、図７に記載の連続起動スートブロワ台数の設定値は前記ボイラ負荷により起動ペア数を可変となるように考慮すると共に、各伝熱面毎に規定本数分連続起動しても汚れ度が下がらない場合でも、同一伝熱面に対して次に起動指令を出せる最小時間を設定して、スートブロワ動作後経過時間にて一定時間起動抑止をかけ、同一伝熱面が長時間連続起動することにより、他の伝熱面のスートブロワが起動できなくなることを防止しておく。
【００５２】
また、石炭性状の相違により熱吸収が大きく変化し蒸気の過熱度が変動するため、スートブロワ起動処理（３）手段７において、蒸気の過熱度を汽水分離器入口温度の目標値に対して、現状の汽水分離器入口温度の偏差がプラス側にあればスートブロワの起動ペア数６３を減少し（蒸気温度が高いということは火炉伝熱面の熱吸収が良いと解され、したがって伝熱面の汚れ度が少ないと判断されて、図７に予め設定された起動ペア数を例えば６から４に減少する）、マイナス側にあればスートブロワの起動ペア数６３を増加するようにし、図７に記載の一回当たりの起動ペア数６３を汽水分離器入口温度偏差およびボイラ負荷により増減できるように、起動ペア数６３の設定の切替が可能な回路構成を合わせて付加させておく。また、前記処理手段７の判定条件である蒸気の過熱度を石炭性状の一つである燃料比により代用することもできる。
【００５３】
次に、前述のスートブロワの連続起動過程において、特に、火炉スートブロワの起動に際しては、図１に示すように、火炉内燃焼ガス温度分布処理手段５により、図５に示すように、バーナゾーンを含む多段の火炉出口ガス温度分布８６，８７を推定する。ここで、図５の８６は基準炭によるガス温度であり、８７は現状炭によるガス温度である。この火炉内燃焼ガス温度分布計算は、ボイラ火炉内における火炎の熱吸収分布より火炉内縦方向ガス温度分布８６，８７を算出するもので、図１に示すように、火炉出口ガス温度計算処理手段４により計算された火炉出口ガス温度（ＦＥＧＴ）７４を基準として燃焼ガスのエンタルピ差により温度分布を求める。
【００５４】
そして、図５の現状の火炉内縦方向ガス温度分布８７を求め、他の条件（例えばメタル温度変化率）を勘案してスートブロアの起動制御を行うことが本発明の他の重要な特徴であって、これについて以下説明する。
【００５５】
火炉内は図５に示すように、基本的に４つのゾーン７０，７１，７２，７３に分割しそれぞれの境界の温度分布９７，９８，９９の計算を行い、バーナゾーンのみ各バーナ段の温度分布１１０，１１１，１１２を計算するのに細分割する。
【００５６】
以下に、火炉内燃焼ガス温度分布の計算方法について説明する。
【００５７】
１．初期設定項目
１．１ 伝熱面積（Ｓ_C）１２０
伝熱面積（Ｓ_C）１２０は、表面伝熱効率（Ａ_R）１２１により投影面積（Ａ_P）１２２の補正を行った面積とする。
【００５８】
ここで、Ａ_P１２２は、垂直面では０．９１、天井及び火炉出口部では０．９７とし壁面の汚れ度（Ａ_SB）１２３により補正を行い、
Ｓ_C＝Ａ_P・Ａ_R・Ａ_SB ………………（７）
で示される。
【００５９】
ここで、Ｓ_C１２０はボイラ火炉全体の伝熱面積であり、各ゾーンでは、
Ｘ−ゾーン ＝Ｓ_X
バーナゾーン＝(i=3)ΣＳ_Bi …（８）
Ｙ−ゾーン ＝Ｓ_Y＋(i=3)ΣＳ_Bi＋Ｐ
Ｚ−ゾーン ＝Ｓ_Z＋Ｓ_Y＋(i=3)ΣＳ_Bi＋Ｒ＝Ｓ_C
となる。
【００６０】
ただし、最上下段のバーナ段はそれぞれ上下５ｆｅｅｔ１３０，１３１の範囲をバーナゾーン７１とし、バーナゾーンを１４０，１４１，１４２，１４３の４つに分割する。バーナゾーンの温度分布１１０，１１１，１１２は、入熱量により配分されるものとして給炭量の比例配分比によって近似し、各ゾーンの伝熱面積９６，９４，９２，９０により算出する。
【００６１】
１．２ 境界条件
炉内燃焼の熱収支によるエンタルピ差ΔＱ_gは、火炎の境界と燃焼ガス量の変数Ｅ・Ｓ_C／Ｗgにより得られる。燃焼ガス温度を基にした境界条件Ｅは、再循環ガス量１５０の影響を考慮しているが、ガス混合による影響は考慮していない。
【００６２】
よって、境界条件Ｅは、
Ｅ＝（Ｅ・Ｓc／Ｗg）・（Ｗg／Ｓc）
となり、ここで、

であり、また、Ｅ・Ｓc／Ｗgは,ΔＱgとＱgoのエンタルピによる関数（グラフ）より、
ΔＱg＝（Ｑgf−Ｑgo）Ｃw …………（１０）
Ｑgf ：炉全体のエンタルピ
となり、Ｑgfは、
Ｑgf＝（ＱgcＷgc＋ＱgrＷgr）／（Ｗgc＋Ｗgr） ……（１１）
Ｑgo：火炉出口燃焼ガスエンタルピ
Ｃw ：湿度による温度補正係数（グラフより）
Ｑgc：燃焼ガスエンタルピ
Ｑgr：再循環ガスエンタルピ
Ｗgc：燃焼ガス量
Ｗgr：再循環ガス量
で表される。
【００６３】
２．火炎の伝熱計算
２．１ バーナゾーン７１
バーナゾーン７１のエンタルピの変化量ｑ_Bは、
【００６４】
【数１２】

【００６５】
で示される。ここで、ΔＱg_Bは、Ｅ・Ｓc／ＷgとＱg_Bの関数で示され、
【００６６】
【数１３】

【００６７】
より得られる。４分割１４０，１４１，１４２，１４３したバーナゾーン７１は、各ゾーンに入る熱量及び伝熱面積をそれぞれ積算して順次計算を行う。（ｑ_Bi，i＝１〜４）
２．２ Ｘ−ゾーン７０
Ｘ−ゾーン７０でのエンタルピの変化量は、
【００６８】
【数１４】

【００６９】
で示され、変数はすべて既述の数式による。
【００７０】
２．３ Ｙ−ゾーン７２
Ｙ−ゾーン７２でのエンタルピの変化量は、バーナゾーン７１との関係より、
【００７１】
【数１５】

【００７２】
ここで、ΔＱg_Yは、Ｅ・Ｓc／ＷgとＱg_Yの関数で与えられ、
【００７３】
【数１６】

【００７４】
【数１７】

【００７５】
によりｑ_Yが求められる。ここで使用する定数は既述のものを用いる。
【００７６】
２．４ Ｚ−ゾーン７３
燃焼ガスのテンパリングゾーンとなるＺ−ゾーン７３でのエンタルピの変化量は、
【００７７】
【数１８】

【００７８】
ここで、ΔＱ_Zは、（Ｅ・Ｓc／Ｗg）と火炉出口エンタルピＱgより得られ、
【００７９】
【数１９】

【００８０】
を用いてｑ_zを算出する。
【００８１】
３．火炉内ガス温度の計算８６，８７
以上の計算により得たｑを表面伝熱効率（Ａ_R）１２１を垂直面と天井、火炉平坦部に分けて、それぞれ算出し、それぞれの有効表面積（垂直面：Ｓ_H，水平面：Ｓ_V）より、エンタルピを得る。
【００８２】
【数２０】

【００８３】
以上より得られたエンタルピおよびガス水分量％（Ｗ_H20）より、火炉出口ガス温度ＦＥＧＴ７４をベースにした熱収支計算によって温度分布を得る。
【００８４】
Ｈ_FEGT＝ｇ（Ｔ_FEGT，Ｗ_H20） …………（２１）
（２０）式よりバーナゾーン７１、Ｙ−ゾーン７２のガス温度Ｔ９８，９７は、 Ｈ_YO＝Ｈ_FEGT＋Ｑ_z
Ｈ_BO＝Ｈ_FEGT＋Ｑ_z＋Ｑ_y
Ｔ_YO＝ｆ（Ｈ_YO，Ｗ_H20）
Ｔ_BO＝ｆ（Ｈ_BO，Ｗ_H20） …………（２２）
次に、バーナゾーン７１から、Ｘ−ゾーン７０への温度分布は、図５に示すＢｕｒｎｅｒ Ｚｏｎｅ Ｅｌｅｖａｔｉｏｎ Ｆａｃｔｏｒ８５により推定する（各缶ごとの特性曲線）。すなわち、係数のカーブを図５に示すバーナゾーン７１でのエンタルピの変化量として、バーナ段ごとに配分して温度を計算する。
【００８５】
例えばある缶においては、次式により計算を行っている。
【００８６】
【数２３】

【００８７】
ここで、ｘはバーナゾーン７１下端よりの高さの割合（％）である。よって、

このようにして、火炉内の温度分布８６，８７の計算値を得る。
【００８８】
以上の説明の通り、図１に示すように、火炉出口ガス温度計算処理手段４にて、図５に示すように、火炉出口ガス温度７４を推定し、図１に示すように、火炉内燃焼ガス温度計算処理手段５にて、図５に示すように、火炉内燃焼ガス温度分布８６，８７を推定することにより、火炉熱負荷の状態を把握する。
【００８９】
図１に示すスートブロワ起動処理（２）手段６において、特に火炉におけるスートブロアを起動する際、図５に示すように、プラント毎の基準炭の当該ガス温度分布８６から、図８に示すように、火炉に設置されるスートブロワを上・中・下段の伝熱面エリアに分割（図６から、缶前後および左右設置のスートブロワを上段２０１、中段２０２とし、缶左右設置のスートブロワを下段２０３に分割）し、本スートブロワが設置されるＹゾーンのガス温度分布を計算する手段３０７にて、前記伝熱面エリア毎にガス温度分布を記憶しておき、現状の炭種におけるガス温度分布８７から、前記と同様にして分割単位毎にガス温度分布の推定値を計算し、前記伝熱面エリア毎にその偏差が基準炭燃焼時に比べて大きいガス温度分布になっているか判定（図８の手段３０９）して、このガス温度の偏差が大きい伝熱面エリアに属するスートブロワを起動する際、図１に示すように、スートブロワ起動処理（１）手段３、スートブロア起動処理（３）手段７にて予め決められた起動ペア数を連続起動していく場合の次ペアへのタイムインターバルを可変（図８の手段３１１）にし、次ペアへのスートブロワの起動インターバルを長くする。
【００９０】
この際、現状のガス温度分布８７が基準炭ガス温度分布８６より規定の偏差以上に高い伝熱面エリアが存在する場合（図８の手段３０８）には、そのゾーンに該当するスートブロアへブロアするようにスートブロワ起動処理（１）手段３、スートブロア起動処理（３）手段７により起動順序が指示された場合には、図８に示す起動可能エリア探索処理手段３１０により、規定の偏差未満の伝熱面エリアに属するスートブロワまで前記起動順序に従いスキップして、ブロア処理を行い、起動可能なエリアがない場合にはブロア処理を中止するように制御する。
【００９１】
また、起動しようとする火炉スートブロワの設置エリア毎（図６の２０１，２０２，２０３を示す）の火炉内燃焼ガス温度大の場合には、図１に示すように、スートブロワ起動処理（２）手段６において、予めメタル温度の設置場所から水壁面単位にグループ分けを行い、本水壁毎のメタル温度の上昇を防止する目的からスートブロワを１ペア目起動した場合に水壁毎に最大値および平均値を計算（図８の手段３１２）し、水壁毎のメタル温度の最大値およびメタル温度差（最大値から平均値を引いた値）を火炉上部水壁および天井壁および副側壁底壁（火炉と後部伝熱壁との間の側壁）出口について監視し、メタル温度監視処理手段３１３により、制限値内であれば次ペアのスートブロワを起動するが、制限値外の場合は、一定時間次の起動順序であるスーブロワへの起動を中断し、一定時間待って回復していれば次ペアのスートブロワを起動し、待っても回復しない時は処理を打ち切る処理機能を合わせて付加しておく。
【００９２】
なお、１ペア目起動後に２ペア目以降を起動する場合も１ペア目起動処理と同様とする。ここにおいて、前記制限値について、メタル温度高およびメタル温度差大の制限値ーαとし、αについては火炉スートブロワが動作したときのメタル温度の上昇分を考慮して決定する。
【００９３】
このようにして、図５におけるスートブロアが設置されているＹゾーンにおける現状のガス温度分布８７が基準のガス温度分布８６より高い場合は、一般的に云って、その箇所の熱吸収量が低下しているためスートブロアを起動するのであるが、スートブロアを起動したことによって汚れが改善されてその結果スートブロアされた箇所の伝熱面の温度上昇が高くなり過ぎてメタルの損傷を引き起こすこともあるので、メタル温度を勘案して故意にスーブロアを止めたり次のペアへのインターバルを長くしたりするものである。
【００９４】
以上説明したようなスートブロワ起動処理を自動的に行うことにより、炭種差による燃料比の違いによる燃焼性、伝熱特性の変動および汚れ度の相違による熱負荷バランスを考慮したスートブロワ運用が可能となる。
【００９５】
また、ボイラ負荷と蒸気の過熱度または燃料比により、起動スートブロワ台数を可変にして制御することもできる。
【００９６】
本発明の他の実施形態として、音速のガス温度依存性を動作原理とする音響式ガス温度計により音波伝播経路の平均ガス温度計測を行い、これから火炉バーナゾーンを含むガス温度を多段に計測して、計算された火炉出口ガス温度（ＦＥＧＴ）を基準として燃焼ガスのエンタルピ差により温度分布を求めるＡＳ Ｍｅｔｈｏｄ（ボイラ火炉内における火炎の熱吸収分布より火炉内縦方向ガス温度分布を算出）により算出した当該ガス温度分布推定値を補間して、火炉のガス温度の連続的な分布をオンライン推定することができる。
【００９７】
この実施形態の効果として、物理モデルを補間として用いることにより物理現象を忠実に反映した温度予測値が得られ、石炭の燃焼特性、つまり、火炉内の熱負荷分布の集中状況が精度よく把握することができ、火炉内の高熱負荷帯へのスートブロワ起動によるメタル温度高を防止しながら自動的にスートブロワ制御を行えることが挙げられる。
【００９８】
以上説明したように、本発明は、主として次のような機能と作用を備えているものである。
【００９９】
▲１▼火炉部と各バンク部の伝熱面の汚れ度を推定し、
▲２▼推定した汚れ度とボイラ運転状況から判断して最適なスートブロア起動箇所を決定し、
▲３▼特に、火炉メタル温度の上昇と火炉熱負荷バランスから火炉部のスートブロアの起動順序と起動ペア数を決定し、
▲４▼ボイラ負荷と蒸気過熱度から１回の起動における起動ペア数を可変（各バンプ部も同様）にし、
▲５▼スートブロワが設置されている火炉のＹゾーンを３分割にに分けて、それぞれのゾーンの火炉内ガス温度分布を現状炭において計算し、これと基準炭でのガス温度分布との偏差を求め、
その偏差が制限値よりも小さいときには、前記▲３▼および▲４▼で決められた起動順序と起動ペア数のスートブロアを実施し、
その偏差が大きいときには次の起動ペアへのインターバルを長くしてスート
ブロアを実施し、
また、その偏差が制限値より大きいとき、その偏差が現れた火炉のゾーンに存在するスートブロアをブロアするように前記▲３▼、▲４▼で指示されたときには、
偏差未満のエリアに属するスートブロワまで起動順序に従いスキップして、ブ
ロア処理を行う。
【０１００】
以上の処理の流れが基本的な技術思想であるが、このような思想の背景は次のとおりである。
【０１０１】
火炉の現状炭のガス温度が基準炭のそれに比べて規定値より高くなる場合、
イ．伝熱面が汚れていて熱吸収されないことが要因である
ロ．石炭性状が要因である（基準炭を中燃料炭と仮定すると、高燃料比炭でプラス側にガス温度偏差大となり、低燃料比炭の場合マイナス側にガス温度偏差大となる）
が考えられ、前記イであれば、ブロアを実施して汚れを落とせば良いが、前記ロであれが、ブロアを実施すると、多少の汚れが落ちてますますメタル温度が上昇し、メタルを傷めることとなる。このメタル損傷だけはどうしても避けねばならない。これが本発明の解決すべき一課題である。
【０１０２】
本発明の特徴は、▲１▼＋▲２▼＋▲３▼を構成要件とするもの、▲１▼＋▲２▼＋▲３▼＋▲４▼を構成要件とするもの、また、▲１▼＋▲２▼＋▲３▼＋▲４▼＋▲５▼を構成要件とするものが挙げられる。
【０１０３】
さらに、本発明は、前記▲１▼、▲２▼、▲３▼、▲４▼、▲５▼を備えると共に、
▲６▼として、火炉上部水壁、副側壁または天井壁出口に設置される温度計により実測された火炉伝熱面のメタル温度の最大値とメタル温度差（最大値ー平均値）（以下、要件Ａという）に基づいて、ブロアの起動制御するものである。即ち、▲１▼＋▲２▼＋▲３▼＋▲４▼＋▲５▼で決められた最初の起動ペアのスートブロア後に前記要件Ａをみて、
この要件Ａが制限値より小さい場合には次の起動ペアを起動し、
この要件Ａが制限値より大きい場合には次の起動ペアを起動させず一定時間待っていて、前記要件Ａを監視する。監視していて前記要件Ａが小さくなれば次の起動ペアを起動し、所定時間待っても回復しなければスートブロア処理を中止する。このように、前記要件Ａの制限値に着目する理由は、ブロアにより汚れが改善してその箇所の伝熱面の温度上昇が高くなりすぎることを防ぐためである。
【０１０４】
【発明の効果】
石炭焚きボイラにおいては使用炭に含まれる灰の融点と成分により伝熱面の汚れ状況が異なる特に石炭性状によりスラッギング性が異なり、同一銘柄炭の石炭でもその伝熱特性が異なる場合もある。
【０１０５】
伝熱面の汚れが問題となるのは、汚れによるボイラ効率の低下に加え、ボイラ静特性の変化、特に火炉の熱吸収割合が変化することにある。例えば火炉が汚れた場合、火炉の熱吸収が小さくなり、火炉内燃焼ガス温度分布が変化し火炉出口ガス温度が上昇する。一方後部伝熱面の熱吸収量が大きくなり、熱吸収のバランスが変化する。
【０１０６】
このように特性がずれることにより、制御操作端の動作範囲が変化し、外乱に対する動作上の余裕が低下する。
【０１０７】
また、熱吸収バランスが変化することから、過熱器スプレー等の操作量に対するゲインおよび時定数も変化し、ＰＩ制御の調整値（制御ゲイン）がずれてくる。
【０１０８】
このように、静特性のずれが制御性能（動特性）の低下要因となる。この外、石炭の燃焼特性の違いにより火炉熱吸収量が変化（主に石炭性状の一つである燃料比に起因する。）するため、火炉内燃焼ガス温度分布がランダムな変動をみせ、火炉内の熱負荷分布が変化することにより、高熱負荷帯へのスートブロワを連続起動することにより、水壁メタル温度の上昇を助長し、ボイラ運用性に影響を与えるなどの問題がある。
【０１０９】
本発明によれば、まず、従来機能であるボイラ伝熱面の汚れ状況から必要な伝熱面に対してスートブロワ運用を行い、熱吸収のバランスを回復させ、静特性のずれによる制御性能の低下を防止することに寄与し、また、物理モデルにより火炉内燃焼ガス温度分布を推定できるので、必要な入熱を確保しつつ、メタル温度高を生じないようにスートブロワ運用が行える効果がある。
【図面の簡単な説明】
【図１】本発明の実施形態に係るインテリジェント型スートブロワ制御装置の構成図である。
【図２】火炉部の伝熱面汚れ計算アルゴリズムを示す図である。
【図３】スートブロアの最適起動箇所を決定処理するための説明図である。
【図４】スートブロアの伝熱面区分と起動順序・台数を示す図である。
【図５】火炉内のガス温度分布を示す図である。
【図６】ボイラにおけるスートブロアの取付位置を示す図である。
【図７】燃料比炭毎及び負荷帯毎における連続起動スートブロア台数の設定値を示す図である。
【図８】 インテリジェント型スートブロワの制御フローを示す流れ図である。
【符号の説明】
１ 伝熱面汚れ度計算処理手段
２ 最適起動伝熱面決定処理手段
３ スートブロア起動処理手段（１）
４ 火炉出口ガス温度計算処理手段
５ 火炉内燃焼ガス温度分布計算処理手段
６ スートブロア起動処理手段（２）
７ スートブロア起動処理手段（３）
１１ 石炭性状
１２ Ｅｃｏ出口Ｏ₂
１３ 燃焼ガス量
１４ 再循環ガス量
１５ トータルガス量
１６ 各バンク部出入口水／蒸気温度
１７ 各バンク部出入口水／蒸気圧力
１８ 各バンク部吸熱量
１９ 各バンク部出入口ガス温度
２０ 火炉出口ガス温度
２１ 火炉有効熱量
２２ 現状火炉有効面積
２３ 設計火炉有効面積
２４ 火炉部伝熱面汚れ度
２５ 現状熱貫流率
２６ 基準熱貫流率
２７ 各バンク部伝熱面汚れ度
６０ 伝熱面区分
６１ 伝熱面名称
６２ 伝熱面内スートブロア順序
６３ 起動ペア数
８６ 基準炭によるガス温度分布
８７ 現状炭によるガス温度[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soot blower control device for a coal-fired boiler, particularly for suppressing fluctuations in thermal load distribution due to furnace gas temperature distribution or heat transfer surface contamination, and reducing the influence on boiler controllability and boiler operability. The present invention relates to a suitable intelligent type soot blower control device.
[0002]
[Prior art]
In coal-fired boilers, the degree of ash and soot adhering to the heat transfer surface of the boiler differs depending on the hardening point and components of the ash contained in the coal used, and in addition to the decrease in heat transfer efficiency due to dirt, the static characteristics of the coal-fired boiler Changes, especially the heat absorption rate of the furnace.
[0003]
For this reason, in a coal fired boiler, a plurality of soot blowers are installed, air and steam are ejected from the soot blower, and the attached ash and soot are removed.
[0004]
Conventionally, the soot blower control device is typically operated in a manual mode in which the soot blower is individually operated or in a sequence mode in which the soot blower is sequentially operated in a certain pattern, and the operation judgment is solely based on the operator. It was.
[0005]
[Problems to be solved by the invention]
As described above, the operation of the conventional soot blower is started according to a preset startup sequence by adjusting the operation timing for the necessary heat transfer surface according to the change in the degree of contamination and the heat collection balance at the operator's discretion. Sequential control was performed.
[0006]
However, in coal-fired boilers that use various types of coal, the amount of coal ash adhering to the heat transfer surface varies depending on the type of coal, so the sequence control that activates the soot blower in a predetermined cycle does not really start. If there is a timing shift from the required time and this is an excessive number of startups, soot blower injection medium consumption will increase and heat transfer surface erosion will occur. A situation such as insufficient power and reduced boiler efficiency will occur.
[0007]
As described above, in the sequential control method in which the soot blower is sequentially activated in accordance with a predetermined activation sequence, when a wide range of coal types is burned, the fuel ratio (ratio of fixed carbon and volatile matter) is one of the coal properties. ) And the effect of dirt on the heat transfer surface of the boiler are interrelated, and the soot blower operation is particularly concerned with the fact that the thermal load characteristics of the furnace vary randomly, especially when the gas temperature distribution in the furnace of a coal fired boiler changes. There was no consideration in terms. For this reason, adjustments can be made for excessive start-up of soot blowers during combustion of coal types with high heat absorption in the furnace and low fuel ratio, and rise in metal temperature due to start-up of soot blowers to heat transfer surface areas in high heat load zones. There was a problem that it was difficult.
[0008]
The object of the present invention is to solve the above-mentioned problems of the prior art, and in particular, the thermal load fluctuations of the furnace due to the difference in heat transfer characteristics due to the fuel ratio which is one of the coal pollution and the degree of soiling of the furnace Taking into account the width, by starting the soot blower so that the furnace heat load is not unbalanced, while ensuring the necessary heat input to the furnace, the furnace gas temperature distribution is estimated so that the metal temperature does not rise, The purpose of the present invention is to provide a soot blower control device that grasps the furnace heat load balance.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention mainly adopts the following configuration.
[0010]
  In the soot blower control device installed in order to remove the ash in the boiler furnace in a boiler facility that uses various types of coal,
  Estimating the furnace outlet gas temperature based on the energy balance of the boiler, and estimating the effective heat amount for the furnace, which is the design condition of the coal-fired boiler furnace,
  From the relationship between the furnace outlet gas temperature and the furnace effective heat quantity, the current furnace effective area is obtained,
  From the ratio of the current furnace effective area and the design furnace effective area, the degree of contamination of the heat transfer surface of the furnace is estimated,
  Define a membership function for each of the estimated furnace surface heat transfer surface contamination level, boiler operating state, and elapsed time since the previous activation, and the defined membership function is an activation that is a high collection of soot blower activation requests. By applying and calculating the rules divided into the side rule group and the suppression side rule group that is a low collection of activation requests, the activation request degree is calculated,
  A soot blower control device that activates a soot blower according to a preset activation order and the number of activation pairs when the calculated activation request level is equal to or greater than an activation threshold value that is an index for activating a soot blower for a furnace. .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 shows a configuration diagram of an intelligent soot blower control apparatus according to an embodiment of the present invention.
[0013]
The present invention is a soot blower control device that is installed in order to remove ash in a boiler furnace in a boiler facility that uses various types of coal, and estimates the degree of contamination of the furnace part and each bank part The heat transfer surface contamination degree calculating means 1 for grasping the contamination state of the heat transfer surface (see FIG. 2),
When the soot blower is started for the heat transfer surface, the optimum soot blower start is determined by comprehensively judging from the fouling inference status of the boiler heat transfer surface estimated by the fouling degree calculation means 1 and the operation state of the boiler using fuzzy reasoning. Optimum starting heat transfer surface determination processing means 2 for determining the location (see FIG. 3),
Soot blower start-up process with the setting function of the soot blower start-up sequence and the number of start-up pairs taking into account the rise in furnace metal temperature and furnace heat load balance due to soot blower start-up on the same heat transfer surface at the heat transfer surface 1) means 3 (see FIGS. 4 and 7),
Soot blower start-up processing (3) means 7 (see FIG. 7) that can make the number of start-up pairs variable depending on the boiler load and the degree of superheat of the steam at the time of one start-up to the furnace and each bank.
Means 4 for calculating the furnace outlet gas temperature by energy balance using the water endothermic heat absorption amount (see FIG. 2);
Means 5 for estimating a multistage furnace gas temperature distribution including a burner zone in the boiler furnace from the temperature calculation means 4;
When starting the soot blower in the heat transfer surface area where the deviation of the furnace gas temperature distribution is large from the estimation means 5, the start-up predetermined in the start-up process (1) means 3 and the start-up process (3) 7 is performed. When continuously starting the sequence and the number of startup pairs, there are multiple soot blower startup processing functions that make the time interval to the next startup pair variable by the deviation of the reference furnace gas temperature distribution and the soot blower startup processing that automatically corrects the startup sequence. When the difference between the maximum value and the maximum value and the average value of each water wall exceeds the limit value, the start processing (1) means 3 and the above When the soot blower is continuously activated in the activation process (3) 7, the soot blower activation process that is temporarily in a standby state until the maximum value and the difference between the maximum value and the average value recover within the limit value. And (2) means 6,
It is composed of
[0014]
In the case of a furnace, the heat transfer surface contamination degree calculation means 1 calculates the current effective furnace area with respect to the design furnace area, and sets the ratio as the contamination degree of the heat transfer surface of the furnace, and the rear heat transfer surface In this case, the current heat transmissivity is calculated with respect to the design heat transmissibility, and the ratio is calculated as the degree of contamination of the rear heat transfer surface (see FIG. 2).
[0015]
The optimum startup heat transfer surface determination processing means 2 calculates priority by fuzzy inference from the degree of contamination and the operating state of the boiler, and determines a heat transfer surface with a higher priority (see FIG. 3).
[0016]
The soot blower start process (1) The means 3 performs the start process of the soot blower in the start order and the number of start pairs predetermined for each heat transfer surface (see FIG. 4).
[0017]
In the soot blower start processing (3) means 7, the number of start pairs of the soot blower is made variable from the boiler load and the degree of superheat of the steam depending on the degree of contamination and the difference in heat transfer characteristics due to the difference in the coal type (see FIG. 7).
[0018]
Further, the furnace outlet gas temperature calculating means 4 calculates the furnace outlet gas temperature, the furnace combustion gas temperature distribution calculating means 5 estimates the multistage furnace gas temperature distribution including the burner zone, and the soot blower start processing (2) means. If the estimated furnace gas temperature distribution value in the heat transfer surface area to be started in step 6 is large compared to the reference value, the starting order is automatically corrected. If the deviation is small, the predetermined number of starting pairs is set. The time interval to the next pair when continuously starting is variable, and if the maximum value of each metal wall and the difference between the maximum value and the average value exceed the limit value, the continuous soot blower is started. Until the metal temperature is restored to the limit value and the difference between the maximum value and the average value is restored to the limit value.
[0019]
As described above, the soot blower injection time interval and the startup sequence are automatically corrected based on the furnace gas temperature distribution, the maximum value of the metal temperature, and the difference between the maximum value and the average value. The soot blower can be controlled so that the thermal efficiency and the furnace heat load are properly maintained.
[0020]
More specifically, in the furnace outlet gas temperature calculation means 4 shown in FIG. 1, as shown in the algorithm of FIG. 2, the coal outlet 11 and the most downstream Eco outlet O of the rear heat transfer section.₂A combustion gas amount 13 is calculated from (economizer outlet oxygen concentration) 12 and a total gas amount 15 is calculated from the gas amount 13 and the recirculation gas amount 14.
[0021]
In addition, the inlet / outlet water / steam temperature 16 in the pipe of each bank section (each heat transfer surface shown in FIG. 4 and referred to as a convection heat transfer section, whereas a furnace refers to a radiant heat transfer section) and each bank section. The endothermic amount 18 of each bank is calculated from the inlet / outlet water / steam pressure 17 in the pipe. The heat absorption amount of each heat transfer surface is obtained from the equation (1) by the water-based energy balance equation.
[0022]
Q = F x (Ho-Hi) (1)
Q: Aqueous heat absorption (Kcal / s)
Ho: Water system exit enthalpy (Kcal / kg)
Hi: Water system enthalpy (Kcal / kg)
F: Flow rate (kg / s)
Further, with respect to the process amount in which the data has a temporal shift (phase difference) such as the gas system state quantity and the water system state quantity, the phase difference is corrected by taking into consideration the heat capacities of the metal and the fluid.
[0023]

Wm: Metal mass (Kg)
Cm: Metal specific heat (Kcal / Kg ° C)
Cf: Fluid specific heat (Kcal / Kg ° C)
Vp: fluid volume (m^Three)
V: Fluid specific volume (m^Three/ Kg)
The expression (1 ') is relative to the heat transfer surface.
Outlet fluid heat amount + Heat transfer surface heat amount = Inlet fluid heat amount + Heat amount lost in gas system
Since this relationship holds, it can be expanded by the following expression representing this.
[0024]
F × Ho + dqt / dt = F × Hi + Q (1 ″)
qt: Temporary heat storage (Kcal / s)
Moreover, in the evaporator installed boiler, since the heat absorption amount of the evaporator cannot be obtained from the water system, it is calculated by the following energy balance equation of the gas system.
[0025]
Q = (tgi-tgo) × Cg × Wg
tgi: Inlet gas temperature (° C)
tgo: outlet gas temperature (° C)
Cg: Gas specific heat (Kcal / Kg ° C)
Wg: Gas amount (Kg / s)
Next, the gas temperature outside the pipe at each bank portion entrance / exit is calculated from the total gas amount 15 and each bank portion endothermic amount 18. The temperature of each part on the gas side outside the tube is calculated by the energy balance equation using the water endothermic amount obtained by the equation (1).
[0026]
That is, if the economizer (Eco) outlet gas temperature is known (if the gas temperature is actually measured), the economizer inlet gas temperature can be obtained from equation (2).
[0027]
In this way, the same calculation is sequentially performed on the heat transfer surface on the upstream side of the gas, so that the furnace outlet gas temperature 20 can be finally obtained.
[0028]
tgi = tgo + {Q / (Cpg · Wg)} (2)
Here, tg: Gas temperature (Each part inlet gas temperature is sequentially calculated from the economizer outlet gas temperature using equation (2))
Q: endothermic amount (calculated from equation (1)) (Kcal / s)
Cpg: Gas specific heat (calculated from gas temperature) (Kcal / kg ° C.)
Wg: Gas amount (calculation) (kg / s)
The current effective furnace area 22 can be known from the relationship between the effective heat quantity (effective area as a radiation source) 21 and the furnace outlet gas temperature 20 which is the design condition of the furnace of the coal fired boiler. In short, if the furnace outlet gas temperature 20 is higher than the design condition, it indicates that the contamination is progressing.
[0029]
Then, as shown in the equation (3), the furnace heat transfer surface contamination degree 24 can be estimated from the ratio of the current effective furnace area and the structure area (design furnace effective area).
[0030]
Furnace contamination degree df = Design effective furnace area / Current effective furnace area (3)
Further, the degree of contamination of the heat transfer surface of the bank is determined based on the heat flow rate of the heat transfer surface.
[0031]
Here, the current heat transmissivity 25 is
Q = K ・ A ・ Δt ……………… （4）
Calculate according to
[0032]
Where Q: Calculated based on endothermic equation (1)
A: Heat transfer area (design value)
Δt: Logarithmic average temperature difference
The reference heat transmissibility 26 is
Ko = (Ucg + Urg) × Ucs / (Ucg + Urg + Ucs) (5)
Where Ucg: Gas side convective heat transfer coefficient (calculated from gas volume and gas temperature)
Urg: Gas-side radiant heat transfer coefficient (calculated from gas temperature)
Ucs: Steam side convective heat transfer coefficient (calculated from steam flow rate and steam temperature)
Calculate according to
[0033]
And as shown in (6) Formula, each bank part heat-transfer surface dirt | cleaning degree 27 can be estimated from the ratio of the present heat-transfer rate and a reference | standard heat-transfer rate.
[0034]
Degree of contamination of heat transfer surface of each bank section df = standard heat transmissivity / current heat transmissivity (6)
In the optimum starting heat transfer surface determination processing means 2, as shown in FIG. 3, membership such as the furnace fouling degree 24 obtained by the equation (3) and the bank heat transfer surface fouling degree 27 obtained by the equation (6), etc. Fuzzy inference of the MIN operation 46 and the MAX operation 47 is performed from the functions 34 and 35 and the rules (initiating side and inhibiting side) 33, 37, 41, 43, and the activation request level (−1 to 0 to +1) 50 is calculated. .
[0035]
The membership function is defined by static boiler operation states 38 and 39, dynamic boiler operation states, and elapsed times 44 and 45 from the previous activation, in addition to the degree of contamination 34 and 35.
[0036]
As the activation request membership functions 35, 39, and 45, a membership function expressing the activation request of the soot blower by a numerical value of -1.0 to 0 to +1.0 (low to high) is considered. In this case, the positive side (0.0 to +1.0) is the high region and the negative side (-1.0 to 0.0) is the low region.
[0037]
Also, the rules 33, 37 and 43 are as shown in FIG.

Is one rule. In the assumption part 60, all membership functions such as the degree of dirt and the boiler state can be defined. In the conclusion part 61, the membership function of the “start request” of the soot blower is defined.
[0038]
Further, a plurality of membership functions can be defined in the assumption portion 60.
[0039]
Also, the rules are divided into an activation side rule group 30 and a suppression side rule group 31 for the soot blower, and a group of rules for which activation requests of the conclusion units 35, 39, 45 are high (positive side) are referred to as the activation side rule group 30. On the contrary, a group of rules having a low activation request (negative side) is defined as a deterrence rule group 31.
[0040]
First, a rule unit conclusion, that is, a MIN operation 46 is performed. For example, in the heat transfer surface contamination degree rule example 32 of (1) in FIG. 3, this calculation is performed when the furnace contamination degree is 1.12 in the membership function 34 of the “furnace contamination degree” of the assumption unit 60. The height of the vertical axis is 0.3. Next, the area of the portion where the vertical axis of the membership function 35 of the conclusion unit 61 “high furnace start request degree” 61 is 0.3 or less (that is, the portion a) is the heat transfer surface contamination degree rule example. This is the conclusion of 32 rule units.
[0041]
Similarly, in the boiler state (static) rule example 36 of (2) in FIG. 3, the conclusion when the furnace outlet gas temperature deviation is + 23 ° C. is ○ b. Similarly, for the deterrence rule group shown in FIG. 3, a rule-by-rule conclusion is obtained (as shown in (4) as a rule for starting a soot blower, for example, a rule indicating how much time has passed since the last soot blower was started). There is also.)
[0042]
The maximum area value is selected by the MAX calculation 47 in the height direction of the conclusions calculated for all the rules, and the ○ c part shown in FIG. 3 is the conclusion of the whole rule (the trapezoidal hatching part including the ○ c part) Indicates a region where the soot blower is provided, and a trapezoidal hatched portion on the left side thereof indicates a region where the soot blower is not provided).
[0043]
The activation request level 50 is calculated by calculating the gravity center calculation 49 for the calculated conclusion.
[0044]
In the determination 51 of the optimum startup position by the above-described processing, the maximum value (priority to the gas upstream side in the case of the same) is calculated from the activation request degrees 50 of each soot blower group, and the value is a constant value (for example, +0. If 5) is exceeded, the group is regarded as optimal and activated.
[0045]
As described above, defining a membership function and performing a MIN operation and a MAX operation is a conventionally known method, and this method is also used in the present invention.
[0046]
In the determination 51 of the optimum start heat transfer surface location, the determination of the start of the soot blower is performed in units of the heat transfer surface 61 of the boiler as shown in FIG. 4 for the soot blower attached at the position shown in FIG. At that time, the heat transfer surface that needs to be operated next is determined.
[0047]
Here, FIG. 4 is a diagram showing the heat transfer surface section and order of the soot blower, and F′CE of the heat transfer surface name of the furnace, which is the radiant heat transfer portion, represents the furnace. Regarding the mounting position of the soot blower, the degree to which molten ash from coal combustion adheres to the furnace wall, superheater, and reheater (as a general evaluation method, the ash basic / acid ratio and ash melting temperature are The arrangement of the boiler soot blower is determined from the relationship between the gas temperature and the effective injection range based on the relationship between the gas temperature and the effective injection range, as in the installation example shown in FIG. In particular, on the furnace wall, soot blowers are concentrated in the vicinity of the uppermost burner where ash adhesion is expected to be high. FIG. 7 is a diagram showing the number of continuously activated soot blowers.
[0048]
And the heat transfer surface of the bank part of the furnace part downstream which is a convection heat transfer part is divided into eight, P-2SH is a pendant (suspended) secondary superheater (Super Heater), H −1RH represents a horizontal (horizontal) primary reheater. Reference signs F, B, R, and L in the soot blower order shown in FIG. 4 represent Front, Back, Right, and Left, respectively.
[0049]
When any of the heat transfer surface start conditions is established, as shown in FIG. 4, the start sequence in the heat transfer surface is distributed to the front and rear cans and the left and right soot blowers in the order of the upper and lower furnaces. Arrange the furnace soot blower installation location and the heat transfer tubes in advance so that they start up, and set a combination that will be a start-up schedule that eliminates the soot blower start-up effect on the same heat transfer tube that causes the furnace metal temperature to rise. At this time, a soot blower start schedule taking into account the heat load balance in the furnace as much as possible is set and determined in advance, and the soot blower start processing (1) means 3 in the registered heat transfer in-plane soot blower sequence. 62 and 63 startup pairs (according to FIG. 4, for example, the total number of soot blowers in the furnace is 16 pairs, but 16 It is designed not to blow all but soot blower for a few pairs.The number of pairs blown in one start is shown in Fig.7), starting from the next soot blower that finished last time Is done.
[0050]
Here, how to determine the number of activation pairs in one activation will be described below. In coal with fast progress of fouling in furnaces, superheaters, and reheaters, from the definitions of the above formulas (3) and (6), it is 1.0 when there is no fouling. Value. The number of soot blowers to be started is set to a value at which the minimum contamination level is about 1.2 or less (about 80% of the effective heat transfer area) when the prescribed number of soot blowers is started for each boiler load zone. In addition, with the same number in each boiler load zone, the lower the load zone, the larger the heat absorption rate in the furnace. The number of starting pairs is determined in consideration of the degree of dirt removal and the effect on heat transfer characteristics.
[0051]
However, in the soot blower activation process (1) means 3, when the soot blower to be activated is not in the automatic mode but in the manual mode, the activation request is applied to the next pair of soot blowers and determined in advance as described above. The heat transfer surface soot blower start will be completed if it starts and finishes or skips for the number of start pairs, and the set value of the number of continuous start soot blowers shown in FIG. The minimum number of start-up commands that can be issued next to the same heat-transfer surface is considered even if the number of start-up pairs is variable, and the degree of contamination does not decrease even if the specified number of lines are continuously started for each heat-transfer surface. The time is set and the activation is suppressed for a certain period of time after the soot blower operation, and the soot blower of the other heat transfer surface is started by starting the same heat transfer surface continuously for a long time. Keep prevented from becoming not be able.
[0052]
In addition, since the heat absorption changes greatly due to the difference in coal properties and the superheat degree of the steam fluctuates, in the soot blower start-up process (3) means 7, If the deviation of the inlet temperature of the brackish water separator is on the plus side, the number of startup pairs of the soot blower is reduced (the high steam temperature is understood to be good heat absorption of the furnace heat transfer surface, and therefore the heat transfer surface becomes dirty. 7, the number of activation pairs preset in FIG. 7 is reduced from, for example, 6 to 4), and if it is on the minus side, the number of activation pairs 63 of the soot blower is increased. A circuit configuration capable of switching the setting of the number of starting pairs 63 is added so that the number 63 of starting pairs per time can be increased or decreased by the steam water separator inlet temperature deviation and the boiler load. Further, the degree of superheat of steam, which is the determination condition of the processing means 7, can be substituted by a fuel ratio that is one of coal properties.
[0053]
Next, in the above-mentioned continuous start-up process of the soot blower, particularly when starting the furnace soot blower, as shown in FIG. 1, the furnace combustion gas temperature distribution processing means 5 includes a burner zone as shown in FIG. Multistage furnace outlet gas temperature distributions 86 and 87 are estimated. Here, 86 in FIG. 5 is the gas temperature by the reference charcoal, and 87 is the gas temperature by the current charcoal. In this furnace combustion gas temperature distribution calculation, furnace longitudinal gas temperature distributions 86 and 87 are calculated from the heat absorption distribution of the flame in the boiler furnace. As shown in FIG. The temperature distribution is obtained from the enthalpy difference of the combustion gas using the furnace outlet gas temperature (FEGT) 74 calculated by 4 as a reference.
[0054]
The other important feature of the present invention is that the vertical gas temperature distribution 87 in the current furnace shown in FIG. 5 is obtained and the soot blower start-up control is performed in consideration of other conditions (for example, the metal temperature change rate). This will be described below.
[0055]
As shown in FIG. 5, the furnace is basically divided into four zones 70, 71, 72, and 73, and the temperature distributions 97, 98, and 99 at the respective boundaries are calculated. Only the burner zone is the temperature of each burner stage. The distributions 110, 111, 112 are subdivided to calculate.
[0056]
Below, the calculation method of combustion gas temperature distribution in a furnace is demonstrated.
[0057]
1. Initial setting items
1.1 Heat transfer area (S_C120
Heat transfer area (S_C) 120 is the surface heat transfer efficiency (A_R) 121, the projected area (A_P) The area where the correction of 122 is performed.
[0058]
Where A_P122 is 0.91 on the vertical surface and 0.97 on the ceiling and furnace outlet, and the degree of contamination of the wall surface (A_SB) 123 to correct,
S_C= A_P・ A_R・ A_SB          ……………… (7)
Indicated by
[0059]
Where S_C120 is the heat transfer area of the entire boiler furnace.
X-zone = S_X
Burner zone = (i = 3) ΣS_Bi ... (8)
Y-zone = S_Y+ (I = 3) ΣS_Bi + P
Z-zone = S_Z+ S_Y+ (I = 3) ΣS_Bi + R = S_C
It becomes.
[0060]
However, the upper and lower burner stages are divided into four zones 140, 141, 142, and 143, with the upper and lower 5 feet 130 and 131 as the burner zone 71, respectively. The burner zone temperature distributions 110, 111, and 112 are approximated by a proportional distribution ratio of the coal supply amount as distributed by the heat input, and are calculated from the heat transfer areas 96, 94, 92, and 90 of each zone.
[0061]
1.2 Boundary conditions
Enthalpy difference ΔQ due to heat balance of furnace combustion_gIs the variable of the boundary of the flame and the amount of combustion gas ES_C/ Wg. The boundary condition E based on the combustion gas temperature considers the influence of the recirculation gas amount 150, but does not consider the influence of gas mixing.
[0062]
Therefore, the boundary condition E is
E = (E ・ Sc / Wg) ・ (Wg / Sc)
Where

E · Sc / Wg is obtained from the function (graph) of ΔQg and Qgo's enthalpy,
ΔQg = (Qgf−Qgo) Cw (10)
Qgf: Entire furnace enthalpy
Qgf is
Qgf = (QgcWgc + QgrWgr) / (Wgc + Wgr) (11)
Qgo: Furnace outlet combustion gas enthalpy
Cw: Temperature correction coefficient due to humidity (from graph)
Qgc: Combustion gas enthalpy
Qgr: Recirculation gas enthalpy
Wgc: Combustion gas amount
Wgr: Recirculation gas volume
It is represented by
[0063]
2. Flame heat transfer calculation
2.1 Burner Zone 71
Change amount q of enthalpy in burner zone 71_BIs
[0064]
[Expression 12]

[0065]
Indicated by Where ΔQg_BIs E · Sc / Wg and Qg_BIt is shown by the function of
[0066]
[Formula 13]

[0067]
More obtained. The burner zone 71 divided into four 140, 141, 142, and 143 performs calculation by sequentially integrating the amount of heat and the heat transfer area entering each zone. (Q_Bi, i = 1-4)
2.2 X-Zone 70
The amount of change in enthalpy in X-zone 70 is
[0068]
[Expression 14]

[0069]
And all variables are according to the mathematical formulas described above.
[0070]
2.3 Y-Zone 72
The amount of change in enthalpy in the Y-zone 72 is based on the relationship with the burner zone 71.
[0071]
[Expression 15]

[0072]
Where ΔQg_YIs E · Sc / Wg and Qg_YGiven by the function
[0073]
[Expression 16]

[0074]
[Expression 17]

[0075]
Q_YIs required. The constants used here are those described above.
[0076]
2.4 Z-Zone 73
The amount of change in enthalpy in the Z-zone 73, which is the tempering zone for the combustion gas, is
[0077]
[Formula 18]

[0078]
Where ΔQ_ZIs obtained from (E · Sc / Wg) and the furnace exit enthalpy Qg,
[0079]
[Equation 19]

[0080]
Q_zIs calculated.
[0081]
3. Calculation of furnace gas temperature 86,87
Q obtained by the above calculation is the surface heat transfer efficiency (A_R) 121 is divided into a vertical surface, a ceiling, and a flat portion of the furnace, and each is calculated, and each effective surface area (vertical surface: S_H, Horizontal plane: S_V) To get enthalpy.
[0082]
[Expression 20]

[0083]
Enthalpy and gas water content% (W_H20) To obtain the temperature distribution by heat balance calculation based on the furnace outlet gas temperature FEGT74.
[0084]
H_FEGT= G (T_FEGT, W_H20) ………… (21)
From the equation (20), the gas temperatures T98 and 97 of the burner zone 71 and the Y-zone 72 are H_YO= H_FEGT+ Q_z
H_BO= H_FEGT+ Q_z+ Q_y
T_YO= F (H_YO, W_H20)
T_BO= F (H_BO, W_H20) ………… (22)
Next, the temperature distribution from the burner zone 71 to the X-zone 70 is estimated by a Burner Zone Elevation Factor 85 shown in FIG. 5 (characteristic curve for each can). That is, the coefficient curve is distributed as the amount of enthalpy change in the burner zone 71 shown in FIG.
[0085]
For example, in a can, calculation is performed by the following formula.
[0086]
[Expression 23]

[0087]
Here, x is a ratio (%) of the height from the lower end of the burner zone 71. Therefore,

In this way, the calculated values of the temperature distributions 86 and 87 in the furnace are obtained.
[0088]
As described above, as shown in FIG. 1, the furnace outlet gas temperature calculation processing means 4 estimates the furnace outlet gas temperature 74 as shown in FIG. 5, and as shown in FIG. As shown in FIG. 5, the gas temperature calculation processing means 5 estimates the combustion gas temperature distributions 86 and 87 in the furnace to grasp the furnace heat load state.
[0089]
In the soot blower starting process (2) means 6 shown in FIG. 1, when starting the soot blower in the furnace in particular, as shown in FIG. 5, from the gas temperature distribution 86 of the reference coal for each plant, as shown in FIG. The soot blower installed in the furnace is divided into upper, middle, and lower heat transfer surface areas (from FIG. 6, the soot blower installed before and after the can and the left and right are divided into the upper stage 201 and the middle stage 202, and the soot blower installed in the left and right cans is divided into the lower stage 203) In the means 307 for calculating the gas temperature distribution in the Y zone where the soot blower is installed, the gas temperature distribution is stored for each heat transfer surface area, and from the gas temperature distribution 87 in the current coal type, In the same manner as above, an estimated value of the gas temperature distribution is calculated for each division unit, and it is determined whether the deviation of the gas temperature distribution is larger for each heat transfer surface area than that for the reference coal combustion. When the soot blower belonging to the heat transfer surface area in which the deviation of the gas temperature is large (means 309 in FIG. 8), as shown in FIG. 1, the soot blower start processing (1) means 3, the soot blower start processing (3 ) When the number of activation pairs determined in advance by means 7 is continuously activated, the time interval to the next pair is made variable (means 311 in FIG. 8), and the activation interval of the soot blower to the next pair is lengthened.
[0090]
At this time, if there is a heat transfer surface area in which the current gas temperature distribution 87 is higher than a specified deviation from the reference coal gas temperature distribution 86 (means 308 in FIG. 8), blow to the soot blower corresponding to that zone. When the activation order is instructed by the soot blower activation process (1) means 3 and the soot blower activation process (3) means 7, heat transfer less than a prescribed deviation is performed by the activatable area search processing means 310 shown in FIG. Control is performed so as to skip to the soot blower belonging to the surface area in accordance with the activation sequence, perform the blower process, and stop the blower process when there is no area that can be activated.
[0091]
In addition, in the case where the furnace combustion gas temperature is large for each installation area of the furnace soot blower to be started (showing 201, 202 and 203 in FIG. 6), as shown in FIG. 1, the soot blower start processing (2) means In Fig. 6, when the first pair of soot blowers is activated for the purpose of preliminarily grouping in units of water wall surface from the place where the metal temperature is installed and preventing the rise of metal temperature for each main water wall, the maximum value and average for each water wall The value is calculated (means 312 in FIG. 8), and the maximum metal temperature and the metal temperature difference (value obtained by subtracting the average value from the maximum value) for each water wall are calculated as the furnace upper water wall, ceiling wall, and sub-side wall bottom wall ( The outlet of the side wall between the furnace and the rear heat transfer wall is monitored, and the soot blower of the next pair is activated by the metal temperature monitoring processing means 313 if the limit value is within the limit value. Origin of Interrupt the boot to a sequence Suburowa, if recovered waiting a predetermined time to start the soot blower of the next pair, when not recover even waiting keep adding together processing function to abort the process.
[0092]
Note that the second and subsequent pairs are activated after the first pair is activated as in the first pair activation process. Here, the limit value is set to a limit value α of the high metal temperature and the large metal temperature difference, and α is determined in consideration of an increase in metal temperature when the furnace soot blower operates.
[0093]
In this way, when the current gas temperature distribution 87 in the Y zone where the soot blower in FIG. 5 is installed is higher than the reference gas temperature distribution 86, generally, the heat absorption amount at that point decreases. The soot blower is started, but the start of the soot blower improves the dirt.As a result, the temperature rise on the heat transfer surface of the soot blower becomes too high, which may cause metal damage. In consideration of the metal temperature, the sub blower is intentionally stopped or the interval to the next pair is lengthened.
[0094]
By automatically performing the soot blower starting process as described above, it becomes possible to operate the soot blower in consideration of the heat load balance due to the combustibility due to the difference in the fuel ratio due to the difference in the coal type, the variation in the heat transfer characteristics, and the difference in the degree of contamination. .
[0095]
Further, the number of starting soot blowers can be varied and controlled according to the boiler load and the degree of superheat of the steam or the fuel ratio.
[0096]
As another embodiment of the present invention, an average gas temperature measurement of the sound wave propagation path is performed by an acoustic gas thermometer whose operating principle is the gas temperature dependency of the sound velocity, and the gas temperature including the furnace burner zone is measured in multiple stages. Calculated by AS Method (calculates longitudinal gas temperature distribution in the furnace from the heat absorption distribution of the flame in the boiler furnace) to obtain the temperature distribution by the enthalpy difference of the combustion gas based on the calculated furnace outlet gas temperature (FEGT) By interpolating the estimated gas temperature distribution, the continuous distribution of the furnace gas temperature can be estimated online.
[0097]
As an effect of this embodiment, by using a physical model as an interpolation, a temperature predicted value that faithfully reflects a physical phenomenon can be obtained, and the combustion characteristics of coal, that is, the concentration state of heat load distribution in the furnace can be accurately grasped. The soot blower control can be automatically performed while preventing the metal temperature from being high due to the start of the soot blower to the high heat load zone in the furnace.
[0098]
As described above, the present invention mainly has the following functions and operations.
[0099]
(1) Estimate the degree of contamination of the heat transfer surface of the furnace and each bank,
(2) Determine the optimum soot blower start point based on the estimated degree of dirt and boiler operating conditions,
(3) In particular, determine the soot blower startup sequence and the number of startup pairs from the rise in furnace metal temperature and the furnace heat load balance,
(4) Change the number of startup pairs in one startup from the boiler load and steam superheat (same for each bump)
(5) Divide the Y zone of the furnace where the soot blower is installed into three parts, calculate the gas temperature distribution in the furnace for each zone for the current coal, and calculate the deviation between this and the gas temperature distribution for the reference coal Seeking
When the deviation is smaller than the limit value, the activation sequence and the number of activation pairs determined in (3) and (4) above are performed,
If the deviation is large, increase the interval to the next activation pair and soot
Carry out blower,
Further, when the deviation is larger than the limit value, when the above (3) and (4) are instructed to blow the soot blower existing in the furnace zone where the deviation appears,
Skip to the soot blower belonging to the area below the deviation according to the startup sequence, and
Lower processing is performed.
[0100]
The above processing flow is the basic technical idea. The background of such an idea is as follows.
[0101]
If the gas temperature of the current coal in the furnace is higher than the specified value compared to that of the reference coal,
I. The reason is that the heat transfer surface is dirty and not absorbed.
B. Coal properties are a factor (assuming the reference coal is medium fuel coal, the gas temperature deviation is large on the plus side with high fuel ratio coal, and the gas temperature deviation is large on the minus side with low fuel ratio coal)
If it is the above, it is only necessary to remove the dirt by carrying out a blower. However, if the blower is carried out, some dirt will be removed. The metal temperature will rise and damage the metal. It will be. Only this metal damage must be avoided. This is one problem to be solved by the present invention.
[0102]
The features of the present invention are as follows: (1) + (2) + (3) as structural requirements, (1) + (2) + (3) + (4) as structural requirements, and (1) Examples of the structural requirements are ▼ + ▲ 2 ▼ + ▲ 3 ▼ + ▲ 4 ▼ + ▲ 5 ▼.
[0103]
Furthermore, the present invention comprises the above-mentioned (1), (2), (3), (4), (5),
As for (6), the maximum metal temperature and the metal temperature difference (maximum value-average value) of the furnace heat transfer surface measured by the thermometer installed at the furnace upper water wall, sub-side wall or ceiling wall outlet (hereinafter referred to as the maximum value) The blower is controlled to start based on requirement A). That is, after the soot blower of the first starting pair determined by (1) + (2) + (3) + (4) + (5), see the requirement A,
If this requirement A is less than the limit value, start the next boot pair,
When the requirement A is larger than the limit value, the requirement A is monitored by waiting for a predetermined time without starting the next activation pair. If the requirement A becomes smaller and the requirement A becomes smaller, the next activation pair is activated, and if it does not recover after waiting for a predetermined time, the soot blower process is stopped. Thus, the reason for paying attention to the limit value of the requirement A is to prevent the contamination from being improved by the blower and the temperature rise of the heat transfer surface at that point from becoming too high.
[0104]
【The invention's effect】
In coal-fired boilers, the heat transfer surface is soiled differently depending on the melting point and components of the ash contained in the coal used, and the slagging property is different depending on the coal properties.
[0105]
The problem of contamination on the heat transfer surface is that, in addition to the decrease in boiler efficiency due to contamination, changes in the boiler static characteristics, in particular, the heat absorption rate of the furnace. For example, when the furnace becomes dirty, the heat absorption of the furnace becomes small, the combustion gas temperature distribution in the furnace changes, and the furnace outlet gas temperature rises. On the other hand, the heat absorption amount of the rear heat transfer surface increases, and the balance of heat absorption changes.
[0106]
Due to the deviation of the characteristics in this way, the operating range of the control operation end changes, and the operating margin against disturbance is reduced.
[0107]
Further, since the heat absorption balance changes, the gain and time constant for the operation amount of the superheater spray and the like also change, and the adjustment value (control gain) of the PI control shifts.
[0108]
As described above, the deviation of the static characteristics becomes a factor of decreasing the control performance (dynamic characteristics). In addition, the furnace heat absorption changes due to the difference in coal combustion characteristics (mainly due to the fuel ratio, which is one of the properties of coal), so the combustion gas temperature distribution in the furnace shows random fluctuations, As the heat load distribution in the interior changes, there is a problem that the soot blower to the high heat load zone is continuously started to promote the rise of the water wall metal temperature and affect the boiler operability.
[0109]
According to the present invention, first, the soot blower operation is performed on the necessary heat transfer surface from the dirt state of the boiler heat transfer surface, which is a conventional function, the heat absorption balance is restored, and the control performance is deteriorated due to the deviation of the static characteristics. In addition, it is possible to estimate the combustion gas temperature distribution in the furnace using a physical model, so that the soot blower operation can be performed while ensuring the necessary heat input and preventing the metal temperature from rising.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an intelligent soot blower control device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a heat transfer surface contamination calculation algorithm of a furnace section.
FIG. 3 is an explanatory diagram for determining an optimum activation location of a soot blower.
FIG. 4 is a view showing a heat transfer surface section of a soot blower, a starting order, and the number of units.
FIG. 5 is a diagram showing a gas temperature distribution in the furnace.
FIG. 6 is a view showing a mounting position of a soot blower in a boiler.
FIG. 7 is a diagram showing set values of the number of continuously activated soot blowers for each fuel specific coal and each load zone.
FIG. 8 is a flowchart showing a control flow of the intelligent soot blower.
[Explanation of symbols]
1 Heat transfer surface contamination degree calculation processing means
2 Optimal starting heat transfer surface determination processing means
3 Soot blower activation processing means (1)
4 Furnace outlet gas temperature calculation processing means
5 Furnace combustion gas temperature distribution calculation processing means
6 Soot blower activation processing means (2)
7 Soot blower activation processing means (3)
11 Coal properties
12 Eco Exit O₂
13 Combustion gas amount
14 Recirculated gas volume
15 Total gas volume
16 Water / steam temperature at each bank
17 Water / steam pressure at each bank
18 Endotherm of each bank
19 Gas temperature at each bank
20 Furnace outlet gas temperature
21 Furnace effective heat
22 Current furnace effective area
23 Design furnace effective area
24 Heat transfer surface contamination level of furnace
25 Current heat flow rate
26 Standard heat flow rate
27 Degree of heat transfer on each bank
60 Heat transfer surface section
61 Heat transfer surface name
62 Heat transfer in-plane soot blower sequence
63 Number of activated pairs
86 Gas temperature distribution with reference coal
87 Current gas temperature by charcoal

Claims (4)

In the soot blower control device installed in order to remove the ash in the boiler furnace in a boiler facility that uses various types of coal,
Estimating the furnace outlet gas temperature based on the energy balance of the boiler, and estimating the effective heat amount for the furnace, which is the design condition of the coal-fired boiler furnace,
From the relationship between the furnace outlet gas temperature and the furnace effective heat quantity, the current furnace effective area is obtained,
From the ratio of the current furnace effective area and the design furnace effective area, the degree of contamination of the heat transfer surface of the furnace is estimated,
Define a membership function for each of the estimated furnace surface heat transfer surface contamination level, boiler operation state, and elapsed time since the previous activation, and the defined membership function is a start that is a collection of high soot blower activation requests. By applying and calculating the rules divided into the side rule group and the suppression side rule group that is a low collection of activation requests, the activation request degree is calculated,
The soot blower is activated in accordance with a preset activation order and the number of activation pairs when the calculated activation request level is equal to or greater than an activation threshold value that is an index for activating a soot blower for a furnace. Soot blower control device. In the soot blower control device installed in order to remove the ash in the boiler furnace in a boiler facility that uses various types of coal,
Estimating the furnace outlet gas temperature based on the energy balance of the boiler, and estimating the effective heat amount for the furnace, which is the design condition of the coal-fired boiler furnace,
From the relationship between the furnace outlet gas temperature and the furnace effective heat quantity, the current furnace effective area is obtained,
From the ratio of the current furnace effective area and the design furnace effective area, the degree of contamination of the heat transfer surface of the furnace is estimated,
Define a membership function for each of the estimated furnace surface heat transfer surface contamination level, boiler operation state, and elapsed time since the previous activation, and the defined membership function is a start that is a collection of high soot blower activation requests. By applying and calculating the rules divided into the side rule group and the suppression side rule group that is a low collection of activation requests, the activation request degree is calculated,
When the calculated start request level is equal to or higher than a start threshold value that serves as an index for starting the soot blower for the furnace, the soot blower is started according to the preset start order and the number of start pairs, and the furnace The combustion gas temperature distribution at the boundary of each combustion zone is estimated, and the combustion gas temperature distribution in the furnace at the start of the soot blower and the previously stored reference coal Calculate the deviation from the furnace combustion gas temperature distribution,
When the soot blower is activated according to the preset activation order and the number of activation pairs based on the activation request level based on the determination of the deviation situation, the activation interval to the next order soot blower is made variable, or the activation A soot blower control device characterized in that the order can be corrected. The soot blower control device according to claim 2,
Based on the difference between the maximum value and the maximum value and the average value for each water wall with respect to the temperature measured by the metal thermometer installed at the furnace upper water wall, sub-side wall or ceiling wall outlet, the maximum value and the maximum value If the difference between the average value and the average value is within the limit value, the next soot blower start is continued.If the difference is equal to or greater than the limit value, the start to the soot blower which is the next start order is interrupted for a certain time, Wait for recovery of the maximum value and the difference between the maximum value and the average value within the limit value, start up the next soot blower, and if it has not recovered even after waiting for a certain period of time, stop the so blower start processing. A soot blower control device. In the soot blower control device according to claim 1, 2, or 3,
A soot blower control device characterized in that the number of pairs of starting soot blowers is variable depending on the boiler load and the degree of superheat of steam or the fuel ratio.

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