1. Oxygen-deficient combustion, incomplete combustion of coal powder
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.
The coal powder is thick and incomplete
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.
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.