報告書番号

W96014

タイトル（和文）

低負荷対応用新型低ＮＯｘバーナのスケールアップ検討（その３）－流線形リングによる検討－

タイトル（英文）

SCALE-UP OF NEW LOW-NOX AND LOW-LOAD STABLE COMBUSTION PULVERIZED COAL BURNER (PART 3)

概要 （図表や脚注は「報告書全文」に掲載しております）

本報告では，１次空気管内に設置した流線形リングにより低負荷時の希薄微粉炭流を濃縮し，安定燃焼を図る低負荷対応用ＣＩ－αバーナを実用化するため，バーナ容量を０．１ｔ／ｈから実規模級の１．５ｔ／ｈにスケールアップした場合の微粉炭濃縮効果ならびに低負荷時燃焼特性について検討した。（１）バーナ外周部の微粉炭濃度は，リングをバーナ出口に近づけるほど増大し，約１．５倍まで濃縮され，石油火力並みの２０％負荷でも安定燃焼できることを確認した。（２）灰中未燃分濃度は２０％までの全ての負荷帯で定格時とほぼ同等の濃度に維持できた。リング無設置時に対する灰中未燃分の低減効果は負荷が低下するほど増大した。（３）ＮＯｘ濃度は，４０％以上の負荷帯で定格負荷時と同等になった。４０％より低い負荷では，負荷の低下に応じてＮＯｘが増大したが，脱硝装置内でのガス滞留時間が増加し脱硝効率が向上するため，排出量の抑制が可能である。

概要 （英文）

TO IMPROVE THE COMBUSTION STABILITY OF THE CI-ALPHA BURNER AT LOW LOAD, A STREAMLINED RING WAS DEVELOPED AS A METHOD TO RAISE THE LOCAL COAL CONCENTRATION IN THE PRIMARY AIR NOZZLE. THE PREVIOUS TEST USING A SMALL-SCALE BURNER (COAL FEED RATE:0.1 T/H) ACHIEVED STABLE COMBUSTION AT 20% LOAD DUE TO THE EFFECT OF THE RING. TO UTILIZE THIS METHOD IN AN ACTUAL POWER PLANT, IT IS NECESSARY TO CONFIRM THE EFFECT OF SCALE-UP ON THE LOW-LOAD COMBUSTION STABILITY. THIS REPORTDESCRIBES THE PULVERIZED COAL CONCENTRATION EFFECT AND THE LOW-LOAD COMBUSTION CHARACTERISTICS WHEN THE COAL FEED BURNER CAPACITY WAS SCALIED-UP FROM 0.1 T/H TO 1.5 T/H. (1)THE PULVERIZED COAL CONCENTRATION OUTSIDE THE PRIMARY AIR NOZZLE ROSE AS THE RING APPROACHED THE BURNER EXIT AND THE LOCAL CONCENTRATION ROSE TO 1.5 TIMES THE MEAN COAL CONCENTRATION IN PRIMARY AIR. DUE TO THE EFFECT OF THE PULVERIZED COAL CONCENTRATION, IT WAS POSSIBLE TO BURN STABLY AT 20% LOAD, THE SAME AS AN OIL BURNER. (2)THE UNBURNED CARBON IN FLY ASH AT LOWER LOAD WAS ALMOST EQUAL TO THAT AT STANDARD LOAD. THE RING WAS EFFFECTIVE IN REDUCING UNBURNED CARBONIN FLY ASH, AND ITS EFFCTWAS GREATER WITH REDUCED LOAD. (3)NOX CONCENTRATION WAS ALMOST HELD BELOW 120 PPM AT OVER 40% LOAD.ALTHOUGH THE NOX CONCENTRATION TENDED TO INCREASE AT UNDER 40% LOAD, IT COULD BE REDUCED SUFFICIENTLY BY THE DENITRIFICATION EQUIPMENT. THE DENITRIFICATION EFFICIENCY IS EXPECTED TO IMPROVE AS A RESULT OF THE INCREASED RESIDENCETIME OF GAS IN THE EQUIPMENT DUE TO THE DECREASED GAS VOLUME.

報告者

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