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

通过调取氧量曲线，运行氧量一般在3%-6.0%之间，能够满足锅炉燃烧需要，且炉渣含碳量升高的同时CO浓度无异常升高趋势，排除缺氧燃烧的可能。
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，燃烧不完全
The coal powder is thick and incomplete

对煤粉进行取样化验，发现甲、乙、丙制粉系统煤粉较粗。煤粉细度设计值R90=25%，实际R90在30%左右。大修后木块分离器筛网进行了更换，运行两年时间磨损严重，杂物进入粗粉分离器（轴向型）影响煤粉分离效果；磨煤机钢球长期不筛球，钢球配比不合适；粗粉分离器挡板运行中受煤粉气流冲击及检修工艺原因开度偏差较大。以上三种情况是造成煤粉偏粗的主要原因。煤粉粗是炉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燃烧器配风差
3. Air distribution difference of burner

低氮燃烧器改造后，机组正常运行中燃烧器配风方式为：一层及七层二次风门全开、二至六层二次风门开度为50%、SOFA风门根据机组负荷开关（满负荷时四层燃尽风门全开），以控制NOx浓度在300mg/m3。炉渣量升高后，将二至六层二次风门全开，始终保持一层SOFA风门全关，其余三层SOFA风门根据机组负荷开关进行排查。经过10天的试验，炉渣含碳量没有明显变化，但NOx浓度平均升高至370mg/m3，这基本上排除了配风原因造成炉渣含碳量升高。
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低氮燃烧器磨损
Low nitrogen burner wear

通过燃烧器区观火孔发现部分低氮燃烧器煤粉气流根部有火星，某些低氮燃烧器区域水冷壁经常出现明显挂焦现象，由此判断低氮燃烧器磨损较严重。
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.

内风膜型燃烧器磨损原因：微油点火燃烧器浓缩分离装置位于燃烧器中间，小油枪投运期间，煤、油在燃烧器内部混烧（热负荷超过金属部件的变形温度）时，导致低氮燃烧器内部件变形烧损。低氮燃烧器磨损、周围结焦，造成煤粉气流紊乱，煤粉不能全部集中到火焰中心燃烧，最终导致不完全燃烧损失增加，这是炉渣含碳量高的主要原因之一。同时也能解释飞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.