Abstract:

In operation of the 600MW boiler of a power plant, the stalling accident of the primary air fan occurred two times continuously. According to

analysis, the main reasons of the primary air fan stalling are that the thermal control logic of the mill is irrational, the calculation of the air coal

ratio is irrational, the coordination logic of the unit is irrational and so on. The preventive measures and treatment method of stalling of the axial flow

primary air fan were proposed. Some technical measures, such as to reform the fan and the pipes layout, to arrange the coal blending of the mill rationally

and to decrease the load adjustment speed of AGC properly, were discussed.

Key words: primary air fan, coal mill, air coal ratio, stall, coordination logic