低氮燃燒器改造后之爐渣含碳量升高

1缺氧燃燒，煤粉燃燒不完全
1. Oxygen-deficient combustion, incomplete combustion of coal powder

通過調取氧量曲線，運行氧量一般在3%-6.0%之間，能夠滿足鍋爐燃燒需要，且爐渣含碳量升高的同時CO濃度無異常升高趨勢，排除缺氧燃燒的可能。
From curve of oxygen, oxygen run, generally between 3% and 6.0%, can meet the needs of the boiler combustion, and higher carbon content of slag CO concentration no abnormal rise trend at the same time, eliminate the possibility of reducing fire.

2煤粉偏粗，燃燒不完全
The coal powder is thick and incomplete

對煤粉進行取樣化驗，發現甲、乙、丙制粉系統煤粉較粗。煤粉細度設計值R90=25%，實際R90在30%左右。大修后木塊分離器篩網進行了更換，運行兩年時間磨損嚴重，雜物進入粗粉分離器（軸向型）影響煤粉分離效果；磨煤機鋼球長期不篩球，鋼球配比不合適；粗粉分離器擋板運行中受煤粉氣流沖擊及檢修工藝原因開度偏差較大。以上三種情況是造成煤粉偏粗的主要原因。煤粉粗是爐渣含碳量升高的原因之一。
Through sampling and testing of coal powder, it was found that the coal powder in the system of a, b and c was thicker. The design value of coal powder fineness R90=25%, and the actual R90 is around 30%. After the overhaul in 2011, the screen mesh of the wooden block separator was replaced, which was badly worn in two years of operation. The entry of debris into the coarse powder separator (axial type) affected the separation effect of coal powder. The steel ball of coal mill does not sieve the ball for a long time. There is a large deviation in the opening degree of the baffle of the coarse powder separator due to the impact of coal powder air flow and the overhaul process. The above three conditions are the main reason for the thick coal powder. The coarse coal powder is one of the reasons for the increase of carbon content in slag.

3燃燒器配風差
3. Air distribution difference of burner

低氮燃燒器改造后，機組正常運行中燃燒器配風方式為：一層及七層二次風門全開、二至六層二次風門開度為50%、SOFA風門根據機組負荷開關（滿負荷時四層燃盡風門全開），以控制NOx濃度在300mg/m3。爐渣量升高后，將二至六層二次風門全開，始終保持一層SOFA風門全關，其余三層SOFA風門根據機組負荷開關進行排查。經過10天的試驗，爐渣含碳量沒有明顯變化，但NOx濃度平均升高至370mg/m3，這基本上排除了配風原因造成爐渣含碳量升高。
N burner after modification, the unit in the normal operation of the burner air distribution mode is: a layer and seven secondary air door fully open, two to six layer secondary throttle opening is 50%, SOFA damper according to unit load switch (full four layer burning air door open), to control NOx concentration in 300 mg/m3. After the amount of slag rises, the secondary air doors of the second to the sixth floors are fully opened, and the SOFA air doors of the first floor are always fully closed. The remaining three SOFA air doors are checked according to the load switches of the unit. After 10 days' test, there was no significant change in the carbon content of slag, but the average concentration of NOx increased to 370mg/m3, which basically eliminated the increase in the carbon content of slag caused by wind distribution.

4低氮燃燒器磨損
Low nitrogen burner wear

通過燃燒器區觀火孔發現部分低氮燃燒器煤粉氣流根部有火星，某些低氮燃燒器區域水冷壁經常出現明顯掛焦現象，由此判斷低氮燃燒器磨損較嚴重。
Through the concept of the burner area fire hole found that some low nitrogen pulverized coal burner air roots have Mars, certain areas of low nitrogen combustion chamber wall often appear obvious coke phenomenon, which determine low nitrogen burner wear more serious.

內風膜型燃燒器磨損原因：微油點火燃燒器濃縮分離裝置位于燃燒器中間，小油槍投運期間，煤、油在燃燒器內部混燒（熱負荷超過金屬部件的變形溫度）時，導致低氮燃燒器內部件變形燒損。低氮燃燒器磨損、周圍結焦，造成煤粉氣流紊亂，煤粉不能全部集中到火焰中心燃燒，最終導致不完全燃燒損失增加，這是爐渣含碳量高的主要原因之一。同時也能解釋飛灰含碳量有所升高的原因。

Endogenous wind membrane type burner abrasion reasons: micro oil ignition burner enrichment separation plant is located in the middle burner, during the operation of small oil gun, coal and oil in internal mixing burner to burn (heat load exceeds the yield temperature of the metal parts), lead to low nitrogen deformation loss items within the burner. N around the burner wear, coking, resulting in pulverized coal air flow disorder, pulverized coal into the center of the flame burning, all can't eventually led to the incomplete combustion loss increase, this is one of the main cause of the high carbon content of slag. It can also explain the increase of carbon content in fly ash.