JP4088204B2

JP4088204B2 - Combustion control device for stoker-type garbage incinerator

Info

Publication number: JP4088204B2
Application number: JP2003163854A
Authority: JP
Inventors: 大偉劉; 明浩山口
Original assignee: Takuma Co Ltd
Current assignee: Takuma Co Ltd
Priority date: 2003-06-09
Filing date: 2003-06-09
Publication date: 2008-05-21
Anticipated expiration: 2023-06-09
Also published as: JP2005003219A

Description

【０００１】
【発明の属する技術分野】
本発明は、ストーカ式ゴミ焼却炉の燃焼制御装置に関する。
【０００２】
【従来の技術】
ストーカ式ゴミ焼却炉の主たる焼却対象である都市ゴミは、一般に水分を多量に含み、燃焼物としてのゴミの成分、発熱量等の性状（ゴミ質）にもバラツキがあるため、ゴミ質に応じた適正な燃焼制御を行う必要がある。このため、ストーカ式ゴミ焼却炉の燃焼制御技術として、種々の方法が提案されており、例えば、ストーカ上のゴミの燃え切り位置を検出して、その結果により燃焼制御を行うもの（例えば、特許文献１、２参照）、ストーカ上のゴミの燃焼火炎を観測して燃焼制御を行うもの（例えば、特許文献３参照）、更には、ゴミ焼却炉の発生する熱エネルギの回収を目的としてボイラの蒸気発生量により燃焼制御を行うもの（例えば、特許文献４、５参照）等がある。
【０００３】
【特許文献１】
特開平０７−１９０３２７号公報
【特許文献２】
特開平０８−２８５２４２号公報
【特許文献３】
特開平０８−１００９１６号公報
【特許文献４】
特開平０９−２７３７３２号公報
【特許文献５】
特開平１０−３３２１２１号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、従来のストーカ上のゴミの燃え切り位置を検出して行う燃焼制御では、燃え切り位置付近を産業用テレビカメラ等で監視して燃え切り位置を制御するものであるため、また、従来のストーカ上のゴミの燃焼火炎を観測して行う燃焼制御は、燃焼火炎を産業用テレビカメラ等により観測してその火炎面積に基づいて燃焼制御を行うものであり、ゴミの成分、発熱量等のゴミ質の変動を即座に捉えることができず、ストーカ上の特定領域（乾燥段、燃焼段）の局所的なゴミの燃焼状態を的確に把握することができなかった。
【０００５】
また、従来のボイラの蒸気発生量による燃焼制御は、所定の蒸気発生量になるように燃焼制御を行うものであり、上記２つの制御方法と同様にゴミ質の変動を即座に捉えることができず、ストーカ上の特定領域（乾燥段、燃焼段）の局所的なゴミの燃焼状態を的確に把握することができなかった。
【０００６】
本発明は、上述の問題点に鑑みてなされたものであり、その目的は、変動するストーカ上の局所的なゴミの燃焼状態を推定し、その推定結果に基づき１次燃焼空気の供給量及びストーカ速度を制御することで、最適なゴミ燃焼状態に導き、ゴミの安定した適正燃焼を実現できるストーカ式ゴミ焼却炉の燃焼制御装置を提供することにある。
【０００７】
【課題を解決するための手段】
この目的を達成するための本発明に係るストーカ式ゴミ焼却炉の燃焼制御装置の第一の特徴構成は、複数のストーカをゴミ搬送方向に沿って分割してなる領域であってストーカ速度と１次燃焼空気の供給量を夫々独立して制御可能なコンパートメントを複数備えてなるストーカ式ゴミ焼却炉において、前記ストーカの部材内部或いは近傍に前記ストーカの温度を測定するストーカ温度センサをゴミ搬送方向に沿って複数分散配置し、前記ストーカ上を移動するゴミ層の表面上部の１次燃焼室内に炉内ガス温度を測定するガス温度センサをゴミ搬送方向に沿って複数分散配置し、前記ストーカ温度センサと前記ガス温度センサの検出温度に基づいて、前記複数のコンパートメントの一部または全部に対し、前記コンパートメント別にストーカ速度と１次燃焼空気の供給量の少なくとも何れか一方の制御を行う制御装置を備えてなる点にある。
【０００８】
上記第一の特徴構成によれば、ストーカ温度センサとガス温度センサの検出温度に基づいて、各コンパートメントにおける局所的なゴミの燃焼状態を推定することができる。そして、ゴミの成分、発熱量等のゴミ質の変動に対し、推定した局所的なゴミの燃焼状態に基づいて最適な燃焼状態へ導くことができ、ゴミ質の変動に対するゴミ燃焼状態の変動を最小限に抑制することができる。更に、かかる燃焼制御によってコンパートメント毎の最適燃焼状態を維持することで、局所的な高温領域をなくすことができ、ストーカの焼損等を防いでストーカの長寿命化が図れる。また、ゴミ燃焼状態を安定化させることにより２次燃焼制御を容易にし、ゴミの燃焼に伴って発生するＣＯ（一酸化炭素）、ＨＣ（炭化水素）等の未燃ガス成分やダイオキシン類の完全燃焼を容易に達成することができる。
【０００９】
同第二の特徴構成は、前記複数のストーカが、ゴミ搬送方向の上流側から下流側に向けて、夫々が１以上の前記コンパートメントを備える乾燥段、燃焼段、及び、後燃焼段に区分され、前記制御装置が、少なくとも前記燃焼段に属する各コンパートメントに対して、前記コンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度が、夫々の所定の適正温度範囲より高い場合に、当該コンパートメントの前記１次燃焼空気の供給量を減らし、前記ストーカ速度を速め、当該コンパートメントの１つ上流側の前記コンパートメントの前記ストーカ速度を遅くする第１の制御パターンを備える点にある。
【００１０】
ここで、ストーカ上のゴミ燃焼過程において、乾燥段では主としてゴミを乾燥させて着火点近傍まで加熱し、燃焼段では主としてゴミを燃焼させ、後燃焼段では主として燃焼段で燃焼したゴミを灰化する。
【００１１】
上記第二の特徴構成によれば、燃焼段におけるゴミ燃焼が最適燃焼か否かを判定し、燃焼段のコンパートメントに係るストーカ温度と炉内ガス温度が適正温度範囲より高い場合は、当該コンパートメントでのゴミ燃焼量が大き過ぎると判断して、当該コンパートメントの１次燃焼空気の供給量を減らし、ストーカ速度を速め、当該コンパートメントの１つ上流側のコンパートメントのストーカ速度を遅くすることで、当該コンパートメントのゴミ燃焼状態を最適な燃焼状態へ導くことができる。従って、燃焼段の全てのコンパートメントに第１の制御パターンを適用することで、燃焼段全体、つまり、ストーカ式ゴミ焼却炉のゴミ燃焼状態を最適状態にすることができる。
【００１２】
同第三の特徴構成は、前記複数のストーカが、ゴミ搬送方向の上流側から下流側に向けて、夫々が１以上の前記コンパートメントを備える乾燥段、燃焼段、及び、後燃焼段に区分され、前記制御装置が、前記ストーカ温度センサと前記ガス温度センサの夫々の複数の検出温度に基づいて、前記燃焼段に属する各コンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度が、夫々の所定の適正温度範囲内にあり、前記乾燥段の最下流のコンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度が、前記燃焼段の最上流のコンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度に比べて夫々所定の温度差を超えて低い場合に、前記乾燥段に属する各コンパートメントの前記１次燃焼空気の供給量を増加させ、前記ストーカ速度を遅くする第２の制御パターンを備える点にある。
【００１３】
上記第三の特徴構成によれば、燃焼段におけるゴミ燃焼が適正な燃焼状態にあるとしても、乾燥段から燃焼段にかけて次第に炉内ガス温度の低い領域が拡大していく傾向を把握でき、かかる場合にゴミ中の水分蒸発が不十分であると判断することができる。この判断結果に基づき、乾燥段のコンパートメントのストーカ速度を遅らせ、１次燃焼空気の供給量を増加させることで乾燥段での水分の蒸発を促進させることができ、結果として、ゴミ質の変動に対し燃焼段における燃焼状態を最適状態に維持することができる。
【００１４】
同第四の特徴構成は、前記複数のストーカが、ゴミ搬送方向の上流側から下流側に向けて、夫々が１以上の前記コンパートメントを備える乾燥段、燃焼段、及び、後燃焼段に区分され、前記制御装置が、前記ストーカ温度センサと前記ガス温度センサの夫々の複数の検出温度に基づいて、前記燃焼段に属する各コンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度が、夫々の所定の適正温度範囲内にあり、前記乾燥段の最下流のコンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度が、前記燃焼段の最上流のコンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度に比べて夫々所定の温度差を超えて高い場合に、前記乾燥段に属する各コンパートメントの前記１次燃焼空気の供給量を減少させ、前記ストーカ速度を早くする第３の制御パターンを備える点にある。
【００１５】
上記第四の特徴構成によれば、燃焼段におけるゴミ燃焼が適正な燃焼状態にあるとしても、燃焼段から乾燥段にかけて次第に炉内ガス温度の高い領域が拡大していく傾向を把握でき、かかる場合にゴミ中の水分蒸発が速過ぎると判断することができる。この判断結果に基づき、乾燥段のコンパートメントのストーカ速度を上げ、１次燃焼空気の供給量を減少させることで乾燥段での水分の蒸発を抑制することができ、結果として、ゴミ質の変動に対し燃焼段における燃焼状態を最適状態に維持することができる。
【００１６】
同第五の特徴構成は、前記複数のストーカが、ゴミ搬送方向の上流側から下流側に向けて、夫々が１以上の前記コンパートメントを備える乾燥段、燃焼段、及び、後燃焼段に区分され、前記制御装置が、前記後燃焼段に属する各コンパートメントに対して、前記コンパートメント内に位置する前記ストーカ温度センサの検出温度と当該コンパートメントに近接して位置する前記ガス温度センサの検出温度が、夫々の所定の適正温度範囲より高い場合に、当該コンパートメントの前記１次燃焼空気の供給量を減らし、前記ストーカ速度を遅くする第４の制御パターンを備える点にある。
【００１７】
上記第五の特徴構成によれば、ゴミ中の燃え難い成分、燃焼段での未燃成分をゆっくりと完全に燃焼させることができる。
【００１８】
同第六の特徴構成は、前記制御装置が、１つの前記コンパートメントに対する異なる制御パターンの適用によって、当該コンパートメントの前記ストーカ速度または前記１次燃焼空気の供給量の制御において相反する制御指示を得た場合は、前記ストーカ速度または前記１次燃焼空気の供給量の変更を行わない点にある。
【００１９】
上記第六の特徴構成によれば、仮に複数の制御パターン間で競合が発生した場合でも、ゴミ質の変動に対して誤った方向への急激な燃焼制御の変更を回避することができ、安定したゴミ燃焼制御を担保できる。
【００２０】
【発明の実施の形態】
本発明に係るストーカ式ゴミ焼却炉の燃焼制御装置（以下、適宜「本発明装置」という。）の実施の形態につき、図面に基づいて説明する。
【００２１】
先ず、本発明装置１の制御対象であるストーカ式ゴミ焼却炉２０は、図１に模式的に示すように、被焼却物であるゴミを受け入れるホッパ２と、ホッパ２内に投入されたゴミを下端部から炉内に押し入れるプッシャ３と、プッシャ３により炉内に投入されたゴミを攪拌搬送しながらその上で焼却処理するストーカ式搬送手段４を備えて構成される。
【００２２】
ストーカ式搬送手段４は、図示しない固定火格子と可動火格子（以下、両火格子を単に「ストーカ」という。）を階段上に組み合わせて構成され、可動火格子の往復運動によってその上に載せたゴミを順次下流側へ搬送可能に構成されている。また、ストーカ式搬送手段４は、ゴミの焼却過程（またはゴミ燃焼過程）における、ゴミを乾燥させて着火点近傍まで加熱する乾燥処理と、ゴミを燃焼させる燃焼処理と、燃焼処理後のゴミを灰化させ、また、その焼却灰中の未燃焼成分を完全に燃焼させる後燃焼処理の３つの処理を夫々分担する乾燥段５と燃焼段６と後燃焼段７を備え、ゴミ搬送方向の上流側から下流側に沿って順番に分割配置される。更に、乾燥段５と燃焼段６と後燃焼段７は、夫々１つまたは複数のコンパートメント８に区分される。図１の実施例では、乾燥段５は２つのコンパートメント８ａ，８ｂを、燃焼段６は４つのコンパートメント８ｃ〜８ｆを、後燃焼段７は１つのコンパートメント８ｇを備えて構成される。尚、乾燥段５と燃焼段６と後燃焼段７のコンパートメント８の個数は、夫々焼却炉の規模に応じて適正な値を採用するものであり、適宜変更可能である。
【００２３】
各コンパートメント８は、ストーカ上のゴミ層９に対して下方から１次燃焼空気を独立して供給可能な風箱１０を備え、各風箱１０には、送風ファン１１で供給される１次燃焼空気の供給量（以下、「１次空気量」という。）を調整可能なダンパ機構１２が各別に設けられている。更に、ストーカ式搬送手段４は、コンパートメント８毎に、ストーカの搬送速度（ストーカ速度）を独立して制御可能に構成されている。
【００２４】
上記構成により、ホッパ２から炉内に投入されたゴミは、ストーカ式搬送手段４上を、乾燥段５、燃焼段６、後燃焼段７と順次搬送され、各コンパートメント８のストーカ下部の風箱１０から供給される１次燃焼空気により焼却された後、焼却灰は、焼却灰排出口１３から炉外へ排出される。
【００２５】
更に、図１に示すように、ストーカ式ゴミ焼却炉２０の炉内の１次燃焼室２１内のゴミ層９の表面上部、つまり、ゴミ層９の表面に近接した上方位置に、炉内ガス温度を測定する熱電対で構成されたガス温度センサ１４をゴミ搬送方向に沿って複数分散配置してある。図１に示す実施例では、乾燥段５の最下流のコンパートメント８の上方に１つ、燃焼段６の上方に３つ、乾燥段７の上方に１つ、合計５つのガス温度センサ１４ａ〜１４ｅがゴミ搬送方向に沿って設けられている。
【００２６】
また、ストーカ式搬送手段４は、コンパートメント８ａ〜８ｇ毎に、ストーカの部材内部にストーカの温度を測定する熱電対で構成されたストーカ温度センサ１５（１５ａ〜１５ｇ）を１つずつ設けている。
【００２７】
ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力は、図１に破線で示すように、自動燃焼制御装置１６に入力され、自動燃焼制御装置１６が、当該温度検出出力に基づいてコンパートメント８毎の１次空気量とストーカ速度を制御可能な構成となっている。自動燃焼制御装置１６は、従来のＰＩＤフードバック制御を基本とした自動燃焼制御（ＡＣＣ制御）を実行可能なコンピュータハードウェアをベースに種々の制御パターンをソフトウェア処理により実行可能な構成となっている。
【００２８】
従って、自動燃焼制御装置１６は、図２に示すように、ガス温度センサ１４とストーカ温度センサ１５の検出した夫々の検出温度に基づき、１次空気量とストーカ速度の制御値を、所定の制御パターンに従って演算する。一方、１次空気量とストーカ速度の夫々を図示しないセンサにより検出し、それらの検出値を自動燃焼制御装置１６に入力する。自動燃焼制御装置１６は、夫々の検出値が演算により求めた制御値となるように、各コンパートメント８に設けられたダンパ機構１２とストーカ（可動火格子）の往復運動を制御するストーカ制御部（図示せず）に対し、コンパートメント８毎に独立したダンパ開度（供給量）とストーカ速度のフィードバック制御を実行する。
【００２９】
次に、自動燃焼制御装置１６が制御値の演算に用いる４つの制御パターンについて説明する。
【００３０】
第１の制御パターンは、乾燥段５の最下流のコンパートメント８ｂと燃焼段６の４つのコンパートメント８ｃ〜８ｆに対して適用される。各コンパートメント８ｂ〜８ｆに対しては同様の制御を独立して行うので、燃焼段６の最上流のコンパートメント８ｃを例に説明する。
【００３１】
自動燃焼制御装置１６は、ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力の内、コンパートメント８ｃに近接するガス温度センサ１４ｂとコンパートメント８ｃのストーカ内のストーカ温度センサ１５ｃの各検出温度に対し、各別に予め設定された適正温度範囲より高いか否かの判定を行う。ここで、各温度センサ１４ｂと１５ｃの検出温度が夫々の適正温度範囲より高い場合、当該領域でのゴミの燃焼量が大き過ぎると判断し、燃焼量を抑制する制御を実施し、燃焼段６におけるゴミ燃焼を適正な状態に導く。
【００３２】
具体的には、検出温度の適正温度範囲からの乖離程度に応じて、コンパートメント８ｃの現状制御値より減少した新たな１次空気量の制御値と、コンパートメント８ｃの現状制御値より増加した新たなストーカ速度の制御値と、コンパートメント８ｃの１つ上流側のコンパートメント８ｂの現状制御値より減少した新たなストーカ速度の制御値を演算する。各制御値が求まると、その制御値に基づき、上述の要領で１次空気量とストーカ速度のフィードバック制御が実行される。ここで、各温度センサ１４ｂと１５ｃの検出温度が夫々の適正温度範囲より高くない場合は、本第１の制御パターンに関しては、現状の制御値が維持される。また、上記の各検出温度と適正温度範囲との比較判定は、ゴミ質の変動に対して迅速に応答できる程度の所定の時間間隔で定期的に実行されるものとする。
【００３３】
第１の制御パターンを連続する５つのコンパートメント８ｂ〜８ｆに対して同時に適用して夫々上記要領で１次空気量とストーカ速度の新たな制御値を求めると、連続する２つのコンパートメント間においてストーカ速度に対する制御値の変化が相反する場合が生じる。例えば、コンパートメント８ｄに各温度センサ１４ｃと１５ｄの検出温度が夫々の適正温度範囲より高い場合は、１つ上流側のコンパートメント８ｃのストーカ速度の制御値は現状より減少するのに対し、コンパートメント８ｃの各温度センサ１４ｂと１５ｃの検出温度も夫々の適正温度範囲より高い場合には、コンパートメント８ｂのストーカ速度の制御値は現状より増加する。この場合、夫々の現状制御値からの変位は正負相殺するので、現状制御値を変化させない制御を行う。或いは、制御値の細かな設定が可能な場合は、その相殺による差だけ現状制御値に対して変化させるようにしても構わない。
【００３４】
ここで、第１の制御パターンが５つのコンパートメント８ｂ〜８ｆに対して夫々独立して適用される結果、ストーカ速度がコンパートメント８毎に独立して制御されてゴミの搬送が不安定となることが懸念されるが、実際のゴミの移動速度は、ストーカ速度の変化に追従して直ぐに変化するものではなく、ゴミの塊としてストーカ上を滑りながらゆっくりと搬送されるので、ゴミの搬送が実用上極端に不安定となることはない。
【００３５】
第２の制御パターンは、乾燥段５の２つのコンパートメント８ａ，８ｂと燃焼段６の４つのコンパートメント８ｃ〜８ｆに対して適用される。第２の制御パターンでは、燃焼段６が適正なゴミ燃焼状態にあって、次第に乾燥段５側から燃焼段６側へと１次燃焼室２１内のガス温度の低い領域が拡大していく傾向が見られた場合に、ゴミ中の水分蒸発が不十分であると判断して、乾燥段５の２つのコンパートメント８ａ，８ｂに対し、ストーカ速度を遅らせ、１次空気量を増加させることにより、ゴミの水分蒸発が促進するような制御を実行する。
【００３６】
具体的には、自動燃焼制御装置１６は、先ず、ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力の内、燃焼段６の４つのコンパートメント８ｃ〜８ｆに対応するガス温度センサ１４ｂ〜１４ｄとストーカ温度センサ１５ｃ〜１５ｆの夫々の検出温度が、各別に予め設定された適正温度範囲（上記第１の制御パターンのものと同じ）内にあるか否かの比較判定を行う。ここで、各検出温度が適正温度範囲内にあれば、燃焼段６が適正なゴミ燃焼状態にあると判断され、以降の処理が実行される。
【００３７】
引き続き、ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力の内、乾燥段５の最下流のコンパートメント８ｂに対応するガス温度センサ１４ａとストーカ温度センサ１５ｂの夫々の検出温度と、燃焼段６の最上流のコンパートメント８ｃに対応するガス温度センサ１４ｂとストーカ温度センサ１５ｃの夫々の検出温度とを比較し、ガス温度とストーカ温度の夫々につき、燃焼段６側の検出温度が各別に予め設定された温度差を超えて低いか否かを判定する。ここで、燃焼段６側の各検出温度が前記各温度差を超えて低い場合に、ガス温度の低い領域が乾燥段５側から燃焼段６側へ拡大傾向にあると判断し、乾燥段５の２つのコンパートメント８ａ，８ｂと燃焼段６の最上流のコンパートメント８ｃの夫々に対応するガス温度センサ１４ａ，１４ｂとストーカ温度センサ１５ａ〜１５ｃの夫々の検出温度に基づき、乾燥段５の２つのコンパートメント８ａ，８ｂに対して、現状制御値より減少した新たなストーカ速度の制御値と、現状制御値より増加した新たな１次空気量の制御値を演算する。各制御値が求まると、その制御値に基づき、上述の要領で１次空気量とストーカ速度のフィードバック制御が実行される。
【００３８】
ここで、乾燥段５側と燃焼段６側間の上記検出温度比較判定において、燃焼段６側の各検出温度が前記各温度差を超えて低くない場合は、本第２の制御パターンに関しては、乾燥段５の２つのコンパートメント８ａ，８ｂに対して、現状の制御値が維持される。また、上記検出温度比較判定は、ゴミ質の変動に対して迅速に応答できる程度の所定の時間間隔で定期的に実行されるものとする。
【００３９】
第３の制御パターンは、上述の第２の制御パターンとは逆の制御となり、同様に、乾燥段５の２つのコンパートメント８ａ，８ｂと燃焼段６の４つのコンパートメント８ｃ〜８ｆに対して適用される。第３の制御パターンでは、燃焼段６が適正なゴミ燃焼状態にあって、次第に燃焼段６側から乾燥段５側へと１次燃焼室２１内のガス温度の高温領域が拡大していく傾向が見られた場合に、ゴミ中の水分蒸発速度が速過ぎると判断して、乾燥段５の２つのコンパートメント８ａ，８ｂに対し、ストーカ速度を増加させ、１次空気量を減少させることにより、ゴミの水分蒸発が抑制するような制御を実行する。
【００４０】
具体的には、自動燃焼制御装置１６は、先ず、ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力の内、燃焼段６の４つのコンパートメント８ｃ〜８ｆに対応するガス温度センサ１４ｂ〜１４ｄとストーカ温度センサ１５ｃ〜１５ｆの夫々の検出温度が、各別に予め設定された適正温度範囲（上記第１の制御パターンのものと同じ）内にあるか否かの比較判定を行う。ここで、各検出温度が適正温度範囲内にあれば、燃焼段６が適正なゴミ燃焼状態にあると判断され、以降の処理が実行される。
【００４１】
引き続き、ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力の内、乾燥段５の最下流のコンパートメント８ｂに対応するガス温度センサ１４ａとストーカ温度センサ１５ｂの夫々の検出温度と、燃焼段６の最上流のコンパートメント８ｃに対応するガス温度センサ１４ｂとストーカ温度センサ１５ｃの夫々の検出温度とを比較し、ガス温度とストーカ温度の夫々につき、乾燥段５側の検出温度が各別に予め設定された温度差を超えて高いか否かを判定する。ここで、乾燥段５側の各検出温度が前記各温度差を超えて高い場合に、ガス温度の高温領域が燃焼段６側から乾燥段５側へ拡大傾向にあると判断し、乾燥段５の２つのコンパートメント８ａ，８ｂと燃焼段６の最上流のコンパートメント８ｃの夫々に対応するガス温度センサ１４ａ，１４ｂとストーカ温度センサ１５ａ〜１５ｃの夫々の検出温度に基づき、乾燥段５の２つのコンパートメント８ａ，８ｂに対して、現状制御値より増加した新たなストーカ速度の制御値と、現状制御値より減少した新たな１次空気量の制御値を演算する。各制御値が求まると、その制御値に基づき、上述の要領で１次空気量とストーカ速度のフィードバック制御が実行される。
【００４２】
ここで、乾燥段５側と燃焼段６側間の上記検出温度比較判定において、乾燥段５側の各検出温度が前記各温度差を超えて高くない場合は、本第３の制御パターンに関しては、乾燥段５の２つのコンパートメント８ａ，８ｂに対して、現状の制御値が維持される。また、上記検出温度比較判定は、ゴミ質の変動に対して迅速に応答できる程度の所定の時間間隔で定期的に実行されるものとする。尚、第２の制御パターンと第３の制御パターンで、上記検出温度比較判定を同時に実行しても構わない。
【００４３】
以上の第１〜第３の制御パターンは、燃焼段６における適正なゴミ燃焼状態をゴミ質の変動等に対して安定的に維持することを主眼とした制御であるが、次に説明する第４の制御パターンは後燃焼段７の処理に関する制御である。従って、第４の制御パターンは、後燃焼段７のコンパートメント８ｇに対して適用される。
【００４４】
自動燃焼制御装置１６は、ガス温度センサ１４とストーカ温度センサ１５の夫々の温度検出出力の内、コンパートメント８ｇに近接するガス温度センサ１４ｅとコンパートメント８ｇのストーカ内のストーカ温度センサ１５ｇの各検出温度に対し、各別に予め設定された適正温度範囲より高いか否かの判定を行う。各温度センサ１４ｂと１５ｃの検出温度が夫々の適正温度範囲より高い場合、後燃焼段７では、ゴミ中の燃え難い成分をゆっくりと時間をかけて燃焼させる必要があるので、１次空気量は上述の第１の制御パターンと同様に減少させるが、ストーカ速度は第１の制御パターンとは逆に減少させる制御を行う。これにより、ゴミをゆっくりと時間をかけて燃焼させながら、単位時間当たりのゴミ燃焼量を抑制し、ガス温度及びストーカ温度を低下させる制御が実行される。ここで、ストーカ速度を第１の制御パターンと同様に増加させる制御を行うと、ゴミ中の未燃焼成分が灰中に残存する可能性があるため、第４の制御パターンでは当該可能性を排除できる。
【００４５】
具体的には、各温度センサ１４ｅと１５ｇの検出温度が夫々の適正温度範囲より高い場合に、検出温度の適正温度範囲からの乖離程度に応じて、コンパートメント８ｇの現状制御値より減少した新たな１次空気量の制御値と新たなストーカ速度の制御値を演算する。各制御値が求まると、その制御値に基づき、上述の要領で１次空気量とストーカ速度のフィードバック制御が実行される。ここで、各温度センサ１４ｅと１５ｇの検出温度が夫々の適正温度範囲より高くない場合は、本第４の制御パターンに関しては、現状の制御値が維持される。また、上記の各検出温度と適正温度範囲との比較判定は、ゴミ質の変動に対して迅速に応答できる程度の所定の時間間隔で定期的に実行されるものとする。
【００４６】
上述の如く、第１〜第３の制御パターンは、燃焼段６における適正なゴミ燃焼状態をゴミ質の変動等に対して安定的に維持することを主眼とした制御であり、乾燥段５と燃焼段６の各コンパートメント８に同時に適用されるため、あるコンパートメント８に対して、１つの制御パターンの適用において、１次空気量またはストーカ速度を増加または減少する指示（制御値の変化）が出て、別の制御パターンの適用において逆の指示が出されるという制御パターン間で競合の発生する可能性がある。そこで、上述の第１の制御パターンにおける連続する２つのコンパートメント間においてストーカ速度に対する制御値の変化が相反する場合の処理と同様に、相反する制御値の変化を相殺して、現状制御値を変化させない制御を行う。或いは、制御値の細かな設定が可能な場合は、その相殺による差だけ現状制御値に対して変化させるようにしても構わない。
【００４７】
尚、上記第１〜第４の制御パターンにおける温度比較判定で使用される予め設定された適正温度範囲や温度差は、試運転時の実験やシミュレーション等で導出された値を用いる。
【００４８】
以下に、別の実施形態につき説明する。
〈１〉ストーカ式搬送手段４を複数のコンパートメント８に区分する際の乾燥段５と燃焼段６と後燃焼段７における夫々のコンパートメント８の数は、焼却炉の規模に応じて変更可能で、上記実施の形態に限定されるものではなく、更に、コンパートメント８の数に応じて、ガス温度センサ１４とストーカ温度センサ１５の個数及び配置箇所も適宜変更可能であり、上記実施の形態に限定されるものではない。
【００４９】
〈２〉上記実施の形態では、ガス温度センサ１４とストーカ温度センサ１５は熱電対を用いて構成したが、各温度センサ１４，１５は熱電対以外の温度センサ素子を用いて構成しても構わない。
【００５０】
〈３〉上記実施の形態では、各制御パターンにおいて、自動燃焼制御装置１６による１次空気量とストーカ速度の制御にフィードバック制御方式を適用したが、その他の制御方式（例えば、フィードフォワード方式等）であっても構わない。
【００５１】
〈４〉上記実施の形態において、自動燃焼制御装置１６は、第１〜第４の４つの制御パターンを同時に実行可能であること前提として説明したが、ゴミ燃焼状態やストーカ式ゴミ焼却炉２０の作動状況に応じて、第１〜第４の制御パターンの内の一部の制御パターンだけを適用可能な状態とする運用も可能である。更に、第１〜第４の４つの制御パターン以外の制御パターンを備えていても構わない。例えば、第１〜第３の制御パターンは、燃焼段６における適正なゴミ燃焼状態をゴミ質の変動等に対して安定的に維持することを主眼とした定常運転時の制御パターンであるため、ストーカ式ゴミ焼却炉２０の起動時の燃焼制御には別の制御パターンを使用するようにしても構わない。
【００５２】
〈５〉上記実施の形態において、自動燃焼制御装置１６は、第１〜第３の各制御パターンの適用時において、ホッパ２へのゴミ投入量及びプッシャ３のゴミの炉内への押し込み速度も、乾燥段５のストーカ速度の制御に応じて制御するようにしても構わない。
【００５３】
【発明の効果】
以上、本発明によれば、ストーカ温度センサとガス温度センサによって検出された各コンパートメントに対応する局所的なストーカ温度と１次燃焼室内のガス温度に基づいて、各コンパートメントにおける局所的なゴミの燃焼状態を推定することができ、ゴミの成分、発熱量等のゴミ質の変動に対し、推定した局所的なゴミの燃焼状態に基づいて最適な燃焼状態へ導くことができ、ゴミ質の変動に対するゴミ燃焼状態の変動を最小限に抑制した安定したストーカ式ゴミ焼却炉の操業が可能となる。
【００５４】
更に、かかる燃焼制御によってコンパートメント毎の最適燃焼状態を維持することで、局所的な高温領域をなくすことができ、ストーカの焼損等を防いでストーカの長寿命化が図れる。また、ゴミ燃焼状態を安定化させることにより２次燃焼制御を容易にし、ゴミの燃焼に伴って発生するＣＯ（一酸化炭素）、ＨＣ（炭化水素）等の未燃ガス成分やダイオキシン類の完全燃焼を容易に達成することができる。
【図面の簡単な説明】
【図１】本発明に係るストーカ式ゴミ焼却炉の要部構造及び燃焼制御装置の制御系統を模式的に示す構成図
【図２】本発明に係るストーカ式ゴミ焼却炉の燃焼制御装置の簡略表記による制御系統図
【符号の説明】
１：ストーカ式ゴミ焼却炉の燃焼制御装置
２：ホッパ
３：プッシャ
４：ストーカ式搬送手段
５：乾燥段
６：燃焼段
７：後燃焼段
８，８ａ〜８ｇ：コンパートメント
９：ゴミ層
１０：風箱
１１：送風ファン
１２：ダンパ機構
１３：焼却灰排出口
１４，１４ａ〜１４ｅ：ガス温度センサ
１５，１５ａ〜１５ｇ：ストーカ温度センサ
１６：自動燃焼制御装置（制御装置）
２０：ストーカ式ゴミ焼却炉
２１：１次燃焼室[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion control device for a stoker-type garbage incinerator.
[0002]
[Prior art]
Municipal waste, which is the main incinerator of the stoker-type waste incinerator, generally contains a large amount of moisture, and there are variations in the properties (garbage quality) of the combustible waste components and the amount of heat generated. It is necessary to perform proper combustion control. For this reason, various methods have been proposed as a combustion control technique for a stoker type garbage incinerator. For example, a burnout position of garbage on a stoker is detected and combustion control is performed based on the result (for example, a patent) (Refer to Documents 1 and 2), which controls combustion by observing the combustion flame of dust on the stoker (see, for example, Patent Document 3), and further, for the purpose of recovering the thermal energy generated by the waste incinerator Some control combustion based on the amount of steam generated (for example, see Patent Documents 4 and 5).
[0003]
[Patent Document 1]
JP 07-190327 A
[Patent Document 2]
Japanese Patent Laid-Open No. 08-285242
[Patent Document 3]
Japanese Patent Laid-Open No. 08-100916
[Patent Document 4]
JP 09-273732 A
[Patent Document 5]
JP-A-10-332121
[0004]
[Problems to be solved by the invention]
However, in the conventional combustion control performed by detecting the burnout position of the garbage on the stoker, the burnout position is monitored by an industrial television camera or the like to control the burnout position. Combustion control performed by observing the combustion flame of garbage on the stalker is to observe the combustion flame with an industrial TV camera etc. and perform combustion control based on the area of the flame. It was not possible to immediately grasp the change in garbage quality, and it was impossible to accurately grasp the local combustion state of garbage in a specific area (drying stage, combustion stage) on the stoker.
[0005]
In addition, the conventional combustion control based on the steam generation amount of the boiler performs the combustion control so that the predetermined steam generation amount is obtained, and the change in the garbage quality can be immediately captured as in the above two control methods. Therefore, it was not possible to accurately grasp the local combustion state of dust in a specific area (drying stage, combustion stage) on the stoker.
[0006]
The present invention has been made in view of the above-described problems, and its purpose is to estimate the local combustion state of dust on a fluctuating stalker, and based on the estimation result, supply amount of primary combustion air and It is an object of the present invention to provide a combustion control device for a stoker-type waste incinerator that leads to an optimum waste combustion state by controlling the stalker speed and can realize stable and proper combustion of waste.
[0007]
[Means for Solving the Problems]
In order to achieve this object, the first characteristic configuration of the combustion control device of the stoker type garbage incinerator according to the present invention is a region obtained by dividing a plurality of stokers along the dust transport direction, and the stoker speed and 1 In a stoker-type garbage incinerator having a plurality of compartments each capable of independently controlling the supply amount of the next combustion air, a stoker temperature sensor for measuring the temperature of the stoker in or near the member of the stoker is disposed in the dust transport direction. A plurality of gas temperature sensors for measuring the gas temperature in the furnace in the primary combustion chamber above the surface of the dust layer moving on the stoker are distributed along the dust transport direction, and the stoker temperature sensor And a stoker speed for each compartment based on the detected temperature of the gas temperature sensor and a part or all of the plurality of compartments. To be in a point which is a control device for performing at least one of control of the supply amount of the primary combustion air.
[0008]
According to said 1st characteristic structure, the combustion state of the local garbage in each compartment can be estimated based on the detected temperature of a stoker temperature sensor and a gas temperature sensor. In addition, it is possible to lead to an optimum combustion state based on the estimated local combustion state of the dust with respect to the change in the waste quality such as the composition of the dust and the calorific value. It can be minimized. Furthermore, by maintaining the optimum combustion state for each compartment by such combustion control, a local high temperature region can be eliminated, and the stoker can be prevented from being burned and the life of the stoker can be extended. Moreover, secondary combustion control is facilitated by stabilizing the waste combustion state, and complete combustion of unburned gas components such as CO (carbon monoxide) and HC (hydrocarbon) and dioxins generated by the combustion of waste Combustion can be easily achieved.
[0009]
In the second characteristic configuration, the plurality of stokers are divided into a drying stage, a combustion stage, and a post-combustion stage each having one or more compartments from the upstream side to the downstream side in the dust transport direction. The control device has, for each compartment belonging to at least the combustion stage, a detected temperature of the stoker temperature sensor located in the compartment and a detected temperature of the gas temperature sensor located in the vicinity of the compartment, respectively. When the temperature is higher than a predetermined appropriate temperature range, the supply amount of the primary combustion air of the compartment is reduced, the stalker speed is increased, and the stalker speed of the compartment one upstream of the compartment is decreased. It is in the point provided with the following control pattern.
[0010]
Here, in the dust combustion process on the stoker, the garbage is mainly dried in the drying stage and heated to near the ignition point, the garbage is mainly burned in the combustion stage, and the garbage burned mainly in the combustion stage is ashed in the post-combustion stage. .
[0011]
According to the second characteristic configuration described above, it is determined whether or not the waste combustion in the combustion stage is optimal combustion, and when the stoker temperature and the furnace gas temperature related to the combustion stage compartment are higher than the appropriate temperature range, It is determined that the amount of dust combustion in the compartment is too large, the supply amount of the primary combustion air in the compartment is reduced, the stalker speed is increased, and the stalker speed of the compartment upstream one of the compartment is decreased, so that the compartment It is possible to lead the dust combustion state to the optimum combustion state. Therefore, by applying the first control pattern to all the compartments of the combustion stage, the entire combustion stage, that is, the waste combustion state of the stoker-type waste incinerator can be optimized.
[0012]
In the third characteristic configuration, the plurality of stokers are divided into a drying stage, a combustion stage, and a post-combustion stage each having one or more compartments from the upstream side to the downstream side in the dust conveyance direction. The control device is based on a plurality of detected temperatures of the stoker temperature sensor and the gas temperature sensor and is close to the detected temperature of the stoker temperature sensor located in each of the compartments belonging to the combustion stage. The temperature detected by the gas temperature sensor located within the predetermined appropriate temperature range is positioned close to the compartment detected by the stoker temperature sensor located in the most downstream compartment of the drying stage. The stoker temperature sensor in which the detected temperature of the gas temperature sensor is located in the uppermost compartment of the combustion stage When the detected temperature is lower than a detected temperature of the gas temperature sensor located in the vicinity of the compartment by exceeding a predetermined temperature difference, the supply amount of the primary combustion air of each compartment belonging to the drying stage is The second control pattern is to increase and slow down the stalker speed.
[0013]
According to the third characteristic configuration described above, even if the garbage combustion in the combustion stage is in an appropriate combustion state, it is possible to grasp the tendency that the region where the in-furnace gas temperature is gradually expanded from the drying stage to the combustion stage. In this case, it can be determined that moisture evaporation in the garbage is insufficient. Based on this judgment result, the evaporation of moisture in the drying stage can be promoted by delaying the stoker speed of the compartment in the drying stage and increasing the supply amount of the primary combustion air. On the other hand, the combustion state in the combustion stage can be maintained at the optimum state.
[0014]
In the fourth characteristic configuration, the plurality of stokers are divided into a drying stage, a combustion stage, and a post-combustion stage each having one or more of the compartments from the upstream side to the downstream side in the dust transport direction. The control device is based on a plurality of detected temperatures of the stoker temperature sensor and the gas temperature sensor and is close to the detected temperature of the stoker temperature sensor located in each of the compartments belonging to the combustion stage. The temperature detected by the gas temperature sensor located within the predetermined appropriate temperature range is positioned close to the compartment detected by the stoker temperature sensor located in the most downstream compartment of the drying stage. The stoker temperature sensor in which the detected temperature of the gas temperature sensor is located in the uppermost compartment of the combustion stage When the detected temperature and the detected temperature of the gas temperature sensor located close to the compartment are higher than a predetermined temperature difference, respectively, the supply amount of the primary combustion air of each compartment belonging to the drying stage is A third control pattern for decreasing and increasing the stalker speed is provided.
[0015]
According to the fourth characteristic configuration, even if the waste combustion in the combustion stage is in an appropriate combustion state, it is possible to grasp the tendency that the region where the gas temperature in the furnace is gradually increased from the combustion stage to the drying stage. In this case, it can be determined that the moisture evaporation in the waste is too fast. Based on this judgment result, the evaporation rate of the moisture in the drying stage can be suppressed by increasing the stoker speed of the compartment in the drying stage and decreasing the supply amount of the primary combustion air. On the other hand, the combustion state in the combustion stage can be maintained at the optimum state.
[0016]
In the fifth characteristic configuration, the plurality of stokers are divided into a drying stage, a combustion stage, and a post-combustion stage, each having one or more compartments, from the upstream side to the downstream side in the dust transport direction. The control device, for each compartment belonging to the post-combustion stage, has a detected temperature of the stoker temperature sensor located in the compartment and a detected temperature of the gas temperature sensor located in the vicinity of the compartment, respectively. When the temperature is higher than the predetermined appropriate temperature range, the fourth control pattern is provided to reduce the supply amount of the primary combustion air of the compartment and to reduce the stoker speed.
[0017]
According to the fifth characteristic configuration, the incombustible component in the garbage and the unburned component in the combustion stage can be burned slowly and completely.
[0018]
In the sixth characteristic configuration, the control device obtains a contradictory control instruction in controlling the stoker speed of the compartment or the supply amount of the primary combustion air by applying different control patterns to one of the compartments. In this case, the stoker speed or the supply amount of the primary combustion air is not changed.
[0019]
According to the sixth feature configuration described above, even if competition occurs between a plurality of control patterns, a sudden change in combustion control in the wrong direction can be avoided even if fluctuations in dust quality occur, and stable The garbage combustion control that was done can be secured.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a combustion control device for a stoker-type waste incinerator according to the present invention (hereinafter referred to as “the present invention device” as appropriate) will be described with reference to the drawings.
[0021]
First, as shown schematically in FIG. 1, a stalker-type garbage incinerator 20 that is a control target of the device 1 of the present invention is configured to receive a hopper 2 that receives garbage that is an incineration object, and trash that has been thrown into the hopper 2. A pusher 3 to be pushed into the furnace from the lower end portion, and a stoker type conveying means 4 for incinerating the dust thrown into the furnace by the pusher 3 while being agitated and conveyed.
[0022]
The stoker-type transfer means 4 is configured by combining a fixed grate and a movable grate (not shown) (hereinafter, both grate are simply referred to as “stalker”) on a staircase, and is placed on the reciprocating motion of the movable grate. It is configured to be able to transport the waste to the downstream side sequentially. In addition, the stoker-type transport means 4 is configured to dry the waste and heat it up to the vicinity of the ignition point in the incineration process (or the dust combustion process), the combustion process for burning the garbage, and the ash after the combustion process. And a drying stage 5, a combustion stage 6, and a post-combustion stage 7, which share the three processes of the post-combustion process for completely combusting the unburned components in the incinerated ash, respectively, and upstream of the dust conveyance direction Are divided and arranged in order along the downstream side. Furthermore, the drying stage 5, the combustion stage 6 and the post-combustion stage 7 are each divided into one or more compartments 8. In the embodiment of FIG. 1, the drying stage 5 is configured with two compartments 8a and 8b, the combustion stage 6 is provided with four compartments 8c to 8f, and the post-combustion stage 7 is provided with one compartment 8g. The number of compartments 8 of the drying stage 5, the combustion stage 6, and the post-combustion stage 7 adopts appropriate values according to the scale of the incinerator, and can be changed as appropriate.
[0023]
Each compartment 8 includes a wind box 10 capable of independently supplying primary combustion air from below to the dust layer 9 on the stoker, and each wind box 10 is supplied with a primary combustion supplied by a blower fan 11. Damper mechanisms 12 that can adjust the air supply amount (hereinafter referred to as “primary air amount”) are provided separately. Furthermore, the stoker type conveying means 4 is configured to be capable of independently controlling the stoker conveying speed (stoker speed) for each compartment 8.
[0024]
With the above configuration, the dust introduced from the hopper 2 into the furnace is sequentially conveyed on the stoker-type conveying means 4 to the drying stage 5, the combustion stage 6, and the post-combustion stage 7, and the wind box below the stoker of each compartment 8 After being incinerated with the primary combustion air supplied from 10, the incineration ash is discharged out of the furnace through the incineration ash discharge port 13.
[0025]
Further, as shown in FIG. 1, the in-furnace gas is located above the surface of the dust layer 9 in the primary combustion chamber 21 in the furnace of the stoker type garbage incinerator 20, that is, above the surface of the dust layer 9. A plurality of gas temperature sensors 14 composed of thermocouples for measuring temperature are arranged in a distributed manner along the dust conveyance direction. In the embodiment shown in FIG. 1, a total of five gas temperature sensors 14a-14e, one above the most downstream compartment 8 of the drying stage 5, three above the combustion stage 6, and one above the drying stage 7. Is provided along the dust conveyance direction.
[0026]
In addition, the stoker type conveying means 4 is provided with one stoker temperature sensor 15 (15a to 15g) composed of a thermocouple for measuring the temperature of the stoker in each of the compartments 8a to 8g.
[0027]
The temperature detection outputs of the gas temperature sensor 14 and the stoker temperature sensor 15 are input to the automatic combustion control device 16 as indicated by the broken line in FIG. 1, and the automatic combustion control device 16 uses the compartment based on the temperature detection output. The primary air amount and the stalker speed every 8 can be controlled. The automatic combustion control device 16 has a configuration capable of executing various control patterns by software processing based on computer hardware capable of executing automatic combustion control (ACC control) based on conventional PID food back control. .
[0028]
Therefore, as shown in FIG. 2, the automatic combustion control device 16 performs predetermined control on the control values of the primary air amount and the stalker speed based on the detected temperatures detected by the gas temperature sensor 14 and the stalker temperature sensor 15, respectively. Calculate according to the pattern. On the other hand, each of the primary air amount and the stalker velocity is detected by a sensor (not shown), and the detected values are input to the automatic combustion control device 16. The automatic combustion control device 16 is a stalker control unit that controls the reciprocating motion of the damper mechanism 12 and the stalker (movable grate) provided in each compartment 8 so that each detected value becomes a control value obtained by calculation. For each compartment 8, independent damper opening (supply amount) and stoker speed feedback control is executed.
[0029]
Next, four control patterns used by the automatic combustion control device 16 for calculating the control value will be described.
[0030]
The first control pattern is applied to the most downstream compartment 8 b of the drying stage 5 and the four compartments 8 c to 8 f of the combustion stage 6. Since the same control is performed independently for each of the compartments 8b to 8f, the uppermost compartment 8c of the combustion stage 6 will be described as an example.
[0031]
The automatic combustion control device 16 adjusts the detected temperatures of the gas temperature sensor 14b and the stalker temperature sensor 15c in the stalker of the compartment 8c among the temperature detection outputs of the gas temperature sensor 14 and the stalker temperature sensor 15 respectively. On the other hand, it is determined whether or not the temperature is higher than the preset appropriate temperature range. Here, when the temperature detected by each of the temperature sensors 14b and 15c is higher than the appropriate temperature range, it is determined that the amount of dust combustion in the region is too large, and control for suppressing the amount of combustion is performed. In this way, the garbage combustion at the plant will be brought into an appropriate state.
[0032]
Specifically, according to the degree of deviation of the detected temperature from the appropriate temperature range, a new control value for the primary air amount that has decreased from the current control value of the compartment 8c and a new control value that has increased from the current control value of the compartment 8c. The control value of the stalker speed and the new control value of the stalker speed decreased from the current control value of the compartment 8b on the upstream side of the compartment 8c are calculated. When each control value is obtained, based on the control value, feedback control of the primary air amount and the stalker speed is executed as described above. Here, when the detected temperatures of the temperature sensors 14b and 15c are not higher than the appropriate temperature ranges, the current control values are maintained with respect to the first control pattern. In addition, the comparison determination between each detected temperature and the appropriate temperature range is periodically performed at a predetermined time interval that allows a quick response to a change in dust quality.
[0033]
When the first control pattern is simultaneously applied to the five consecutive compartments 8b to 8f and new control values of the primary air amount and the stalker speed are obtained in the above-described manner, the stalker speed is calculated between the two consecutive compartments. In some cases, the control value changes with respect to each other. For example, if the detected temperature of each of the temperature sensors 14c and 15d is higher than the appropriate temperature range in the compartment 8d, the control value of the stoker speed of the compartment 8c on the upstream side decreases from the current state, whereas the control value of the compartment 8c When the detected temperature of each temperature sensor 14b and 15c is also higher than the appropriate temperature range, the control value of the stoker speed of the compartment 8b increases from the current value. In this case, since the displacement from each current control value cancels out the positive and negative, control is performed without changing the current control value. Alternatively, when a fine control value can be set, the current control value may be changed by the difference due to the cancellation.
[0034]
Here, as a result of the first control pattern being independently applied to the five compartments 8b to 8f, the stalker speed is independently controlled for each compartment 8, and the conveyance of dust becomes unstable. Although there is a concern, the actual movement speed of garbage does not change immediately following the change in the stalker speed, but it is transported slowly while sliding on the stalker as a lump of garbage. There is no extreme instability.
[0035]
The second control pattern is applied to the two compartments 8a and 8b of the drying stage 5 and the four compartments 8c to 8f of the combustion stage 6. In the second control pattern, the combustion stage 6 is in an appropriate dust combustion state, and the region where the gas temperature in the primary combustion chamber 21 is low gradually expands from the drying stage 5 side to the combustion stage 6 side. When the water vapor is seen, the moisture evaporation in the garbage is judged to be insufficient, and the two compartments 8a and 8b of the drying stage 5 are slowed down to increase the primary air amount by slowing the stalker speed. Control is performed to promote the evaporation of moisture in the garbage.
[0036]
Specifically, the automatic combustion control device 16 firstly includes the gas temperature sensors 14b to 14f corresponding to the four compartments 8c to 8f of the combustion stage 6 among the temperature detection outputs of the gas temperature sensor 14 and the stoker temperature sensor 15, respectively. 14d and the stoker temperature sensors 15c to 15f are compared to determine whether or not each of the detected temperatures is within an appropriate temperature range set in advance (the same as that of the first control pattern). Here, if each detected temperature is within an appropriate temperature range, it is determined that the combustion stage 6 is in an appropriate dust combustion state, and the subsequent processing is executed.
[0037]
Subsequently, of the respective temperature detection outputs of the gas temperature sensor 14 and the stoker temperature sensor 15, the detected temperatures of the gas temperature sensor 14a and the stoker temperature sensor 15b corresponding to the most downstream compartment 8b of the drying stage 5, and the combustion stage 6 are compared with the detected temperatures of the gas temperature sensor 14b and the stoker temperature sensor 15c corresponding to the uppermost compartment 8c, and the detected temperature on the combustion stage 6 side is preset for each of the gas temperature and the stoker temperature. It is determined whether or not the temperature difference exceeds the set temperature difference. Here, when each detected temperature on the combustion stage 6 side is lower than the temperature difference, it is determined that the region where the gas temperature is low tends to expand from the drying stage 5 side to the combustion stage 6 side. The two compartments of the drying stage 5 based on the detected temperatures of the gas temperature sensors 14a, 14b and the stoker temperature sensors 15a-15c corresponding to the uppermost compartment 8c of the combustion stage 6 and the compartments 8a, 8b of the combustion stage 6, respectively. For 8a and 8b, a new stoker speed control value decreased from the current control value and a new primary air amount control value increased from the current control value are calculated. When each control value is obtained, based on the control value, feedback control of the primary air amount and the stalker speed is executed as described above.
[0038]
Here, in the detected temperature comparison determination between the drying stage 5 side and the combustion stage 6 side, when the detected temperatures on the combustion stage 6 side are not lower than the temperature differences, the second control pattern will be described. The current control values are maintained for the two compartments 8a and 8b of the drying stage 5. The detected temperature comparison determination is performed periodically at a predetermined time interval that allows a quick response to changes in dust quality.
[0039]
The third control pattern is opposite to the above-described second control pattern, and is similarly applied to the two compartments 8a and 8b of the drying stage 5 and the four compartments 8c to 8f of the combustion stage 6. The In the third control pattern, the combustion stage 6 is in an appropriate dust combustion state, and the high temperature region of the gas temperature in the primary combustion chamber 21 gradually expands from the combustion stage 6 side to the drying stage 5 side. When the water vapor evaporation rate is seen, it is determined that the water evaporation rate in the garbage is too fast, and for the two compartments 8a and 8b of the drying stage 5, the stoker speed is increased and the primary air amount is decreased. Control is performed to prevent the evaporation of dust moisture.
[0040]
Specifically, the automatic combustion control device 16 firstly includes the gas temperature sensors 14b to 14f corresponding to the four compartments 8c to 8f of the combustion stage 6 among the temperature detection outputs of the gas temperature sensor 14 and the stoker temperature sensor 15, respectively. 14d and the stoker temperature sensors 15c to 15f are compared to determine whether or not each of the detected temperatures is within an appropriate temperature range set in advance (the same as that of the first control pattern). Here, if each detected temperature is within an appropriate temperature range, it is determined that the combustion stage 6 is in an appropriate dust combustion state, and the subsequent processing is executed.
[0041]
Subsequently, of the respective temperature detection outputs of the gas temperature sensor 14 and the stoker temperature sensor 15, the detected temperatures of the gas temperature sensor 14a and the stoker temperature sensor 15b corresponding to the most downstream compartment 8b of the drying stage 5, and the combustion stage 6 is compared with the detected temperatures of the gas temperature sensor 14b and the stoker temperature sensor 15c corresponding to the uppermost compartment 8c, and the detected temperature on the drying stage 5 side is set in advance separately for each of the gas temperature and the stoker temperature. It is determined whether or not the measured temperature difference is high. Here, when each detected temperature on the drying stage 5 side is higher than the temperature difference, it is determined that the high temperature region of the gas temperature tends to expand from the combustion stage 6 side to the drying stage 5 side. The two compartments of the drying stage 5 based on the detected temperatures of the gas temperature sensors 14a and 14b and the stoker temperature sensors 15a to 15c respectively corresponding to the two compartments 8a and 8b and the uppermost compartment 8c of the combustion stage 6 A new stoker speed control value increased from the current control value and a new primary air amount control value decreased from the current control value are calculated for 8a and 8b. When each control value is obtained, based on the control value, feedback control of the primary air amount and the stalker speed is executed as described above.
[0042]
Here, in the detection temperature comparison determination between the drying stage 5 side and the combustion stage 6 side, when the detected temperatures on the drying stage 5 side are not higher than the temperature differences, the third control pattern is as follows. The current control values are maintained for the two compartments 8a and 8b of the drying stage 5. The detected temperature comparison determination is performed periodically at a predetermined time interval that allows a quick response to changes in dust quality. Note that the detected temperature comparison determination may be performed simultaneously with the second control pattern and the third control pattern.
[0043]
The first to third control patterns described above are controls mainly intended to stably maintain an appropriate dust combustion state in the combustion stage 6 against changes in dust quality, etc. The control pattern 4 is control related to the processing of the post-combustion stage 7. Therefore, the fourth control pattern is applied to the compartment 8g of the post-combustion stage 7.
[0044]
The automatic combustion control device 16 adjusts the detected temperatures of the gas temperature sensor 14e and the stalker temperature sensor 15g in the stalker of the compartment 8g among the temperature detection outputs of the gas temperature sensor 14 and the stalker temperature sensor 15 respectively. On the other hand, it is determined whether or not the temperature is higher than the preset appropriate temperature range. When the detected temperatures of the temperature sensors 14b and 15c are higher than their proper temperature ranges, the post-combustion stage 7 needs to slowly burn incombustible components in the garbage over time, so the primary air amount is Although it is decreased in the same manner as the first control pattern described above, the stalker speed is controlled to be decreased opposite to the first control pattern. As a result, control is performed to suppress the amount of dust combustion per unit time and reduce the gas temperature and stalker temperature while burning the dust slowly over time. Here, if control is performed to increase the stalker speed in the same manner as the first control pattern, unburned components in the garbage may remain in the ash, so the fourth control pattern eliminates this possibility. it can.
[0045]
Specifically, when the detected temperature of each of the temperature sensors 14e and 15g is higher than the appropriate temperature range, a new value decreased from the current control value of the compartment 8g according to the degree of deviation of the detected temperature from the appropriate temperature range. A control value for the primary air amount and a new control value for the stalker speed are calculated. When each control value is obtained, based on the control value, feedback control of the primary air amount and the stalker speed is executed as described above. Here, when the detected temperatures of the temperature sensors 14e and 15g are not higher than the appropriate temperature ranges, the current control values are maintained for the fourth control pattern. In addition, the comparison determination between each detected temperature and the appropriate temperature range is periodically performed at a predetermined time interval that allows a quick response to a change in dust quality.
[0046]
As described above, the first to third control patterns are controls mainly intended to stably maintain an appropriate dust combustion state in the combustion stage 6 against fluctuations in the quality of dust, and the like. Since it is applied to each compartment 8 of the combustion stage 6 at the same time, an instruction (change in control value) to increase or decrease the primary air amount or the stoker speed is given to a certain compartment 8 when one control pattern is applied. Thus, there is a possibility that a conflict occurs between the control patterns in which a reverse instruction is issued when another control pattern is applied. Therefore, the current control value is changed by canceling the contradictory change in the control value in the same manner as the processing in the case where the change in the control value with respect to the stalker speed is contradictory between the two consecutive compartments in the first control pattern described above. Do not control. Alternatively, when a fine control value can be set, the current control value may be changed by the difference due to the cancellation.
[0047]
In addition, the value derived | led-out by experiment, simulation, etc. at the time of a test run is used for the preset appropriate temperature range and temperature difference which are used by the temperature comparison determination in the said 1st-4th control pattern.
[0048]
Hereinafter, another embodiment will be described.
<1> The number of compartments 8 in the drying stage 5, the combustion stage 6, and the post-combustion stage 7 when dividing the stoker type conveying means 4 into a plurality of compartments 8 can be changed according to the scale of the incinerator, The present invention is not limited to the above embodiment, and the number and arrangement location of the gas temperature sensor 14 and the stoker temperature sensor 15 can be appropriately changed according to the number of compartments 8, and is limited to the above embodiment. It is not something.
[0049]
<2> In the above embodiment, the gas temperature sensor 14 and the stoker temperature sensor 15 are configured using thermocouples, but each temperature sensor 14, 15 may be configured using a temperature sensor element other than the thermocouple. Absent.
[0050]
<3> In the above embodiment, the feedback control method is applied to control the primary air amount and the stalker speed by the automatic combustion control device 16 in each control pattern, but other control methods (for example, the feed forward method) It does not matter.
[0051]
<4> In the above embodiment, the automatic combustion control device 16 has been described on the assumption that the first to fourth control patterns can be executed simultaneously. However, the garbage combustion state and the stoker-type waste incinerator 20 Depending on the operating situation, it is also possible to operate in a state where only a part of the first to fourth control patterns can be applied. Furthermore, control patterns other than the first to fourth control patterns may be provided. For example, the first to third control patterns are control patterns at the time of steady operation with the main purpose of stably maintaining an appropriate dust combustion state in the combustion stage 6 against fluctuations in dust quality, etc. Another control pattern may be used for the combustion control at the time of activation of the stoker type incinerator 20.
[0052]
<5> In the above embodiment, the automatic combustion control device 16 also determines the amount of dust input to the hopper 2 and the speed of pushing the dust of the pusher 3 into the furnace when each of the first to third control patterns is applied. The control may be performed in accordance with the control of the stoker speed of the drying stage 5.
[0053]
【The invention's effect】
As described above, according to the present invention, based on the local stoker temperature corresponding to each compartment detected by the stoker temperature sensor and the gas temperature sensor and the gas temperature in the primary combustion chamber, the local combustion of dust in each compartment. The state can be estimated, and with respect to changes in dust quality such as the composition of the waste and calorific value, the optimum combustion state can be derived based on the estimated local combustion state of dust, and This makes it possible to operate a stable stoker-type garbage incinerator that minimizes fluctuations in the state of garbage combustion.
[0054]
Furthermore, by maintaining the optimum combustion state for each compartment by such combustion control, a local high temperature region can be eliminated, and the stoker can be prevented from being burned and the life of the stoker can be extended. Moreover, secondary combustion control is facilitated by stabilizing the waste combustion state, and complete combustion of unburned gas components such as CO (carbon monoxide) and HC (hydrocarbon) and dioxins generated by the combustion of waste Combustion can be easily achieved.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing the main structure of a stoker-type waste incinerator and a control system of a combustion control device according to the present invention.
FIG. 2 is a control system diagram in simplified form of a combustion control device for a stoker type garbage incinerator according to the present invention.
[Explanation of symbols]
1: Combustion control device for stoker-type garbage incinerator
2: Hopper
3: Pusher
4: Stoker-type transfer means
5: Drying stage
6: Combustion stage
7: Post-combustion stage
8, 8a-8g: compartment
9: Garbage layer
10: Wind box
11: Blower fan
12: Damper mechanism
13: Incineration ash outlet
14, 14a-14e: Gas temperature sensor
15, 15a-15g: Stoker temperature sensor
16: Automatic combustion control device (control device)
20: Stoker-type garbage incinerator
21: Primary combustion chamber

Claims

An area formed by dividing a plurality of stalkers along the dust transport direction, and having a plurality of compartments capable of independently controlling the stalker speed and the supply amount of primary combustion air , wherein the plurality of stalkers are disposed in the dust transport direction. In a stoker-type garbage incinerator that is divided into a drying stage, a combustion stage, and a post-combustion stage each having one or more compartments from the upstream side to the downstream side of
A plurality of stalker temperature sensors for measuring the temperature of the stalker in or near the stalker member are arranged in a distributed manner along the dust conveyance direction,
A plurality of gas temperature sensors for measuring the gas temperature in the furnace are dispersed in the primary combustion chamber above the surface of the dust layer moving on the stoker along the dust conveyance direction,
Based on the detected temperatures of the stoker temperature sensor and the gas temperature sensor, at least one of the stoker speed and the supply amount of primary combustion air is controlled for some or all of the plurality of compartments for each compartment. Equipped with a control device ,
For each compartment belonging to at least the combustion stage, the control device has a detected temperature of the stoker temperature sensor located in the compartment and a detected temperature of the gas temperature sensor located in the vicinity of the compartment, respectively. When the temperature is higher than a predetermined proper temperature range, the supply amount of the primary combustion air of the compartment is reduced, the stalker speed is increased, and the stalker speed of the compartment one upstream of the compartment is decreased. A combustion control device for a stoker-type garbage incinerator characterized by comprising a control pattern .

Before SL controller, wherein the stoker temperature sensor based on a plurality of detected temperature of each of the gas temperature sensors, proximity to the detected temperature and the compartment of the stoker temperature sensor located in each compartment belonging to the combustion stage The temperature detected by the gas temperature sensor located within the predetermined appropriate temperature range is positioned close to the compartment detected by the stoker temperature sensor located in the most downstream compartment of the drying stage. The detected temperature of the gas temperature sensor is predetermined in comparison with the detected temperature of the stoker temperature sensor located in the uppermost compartment of the combustion stage and the detected temperature of the gas temperature sensor located in the vicinity of the compartment. Of the compartments belonging to the drying stage when the temperature difference is lower than Increasing the supply amount of combustion air, a combustion control apparatus for a stoker waste incinerator of claim 1, the second control pattern to slow the stoker speed, and further comprising.

Before SL controller, wherein the stoker temperature sensor based on a plurality of detected temperature of each of the gas temperature sensors, proximity to the detected temperature and the compartment of the stoker temperature sensor located in each compartment belonging to the combustion stage The temperature detected by the gas temperature sensor located within the predetermined appropriate temperature range is positioned close to the compartment detected by the stoker temperature sensor located in the most downstream compartment of the drying stage. The detected temperature of the gas temperature sensor is predetermined in comparison with the detected temperature of the stoker temperature sensor located in the uppermost compartment of the combustion stage and the detected temperature of the gas temperature sensor located in the vicinity of the compartment. Of the compartments belonging to the drying stage when the temperature difference is higher than Reducing the supply amount of combustion air, a combustion control apparatus for a stoker waste incinerator according to the third control pattern to speed up the stoker speed, to claim 1 or 2, further comprising.

Prior Symbol controller for each compartment belonging to the post-combustion stage, the detected temperature of the gas temperature sensor located proximate to the detected temperature and the compartment of the stoker temperature sensor located in said compartment, respectively when a predetermined higher than the appropriate temperature range of, claims 1 to 3 for reducing the supply amount of the primary combustion air in the compartment, a fourth control pattern to slow the stoker speed, and further comprising The combustion control device for a stoker-type garbage incinerator according to any one of the above.

When the control device obtains a contradictory control instruction in the control of the stoker speed of the compartment or the supply amount of the primary combustion air by applying different control patterns to one of the compartments, the control apparatus The combustion control device for a stoker-type refuse incinerator according to any one of claims 1 to 4 , wherein the supply amount of the primary combustion air is not changed.