The process of NO x formation is influenced by some factors,such as characteristics of fuel,surplus air ratio,primary air ratio,secondary air ratio,combustion temperature and so on,which is mainly discussed in this paper from the aspects of technology.

In order to obtain optimum operation of boilers and then ensure timely ignition and completely burnout of pulverized coal, pulverized coal combustion processes in a 350MW boiler were numerically calculated under different primary air ratios and pulverized coal fineness.

As a result,the opening of inlet damper is so small that the primary air pressure is too high and some pressure energy depletes during throttling with too much power consumption in pulverizing system.

There are no existing design criteria for primary fan and blower volume and pressure head design margins.

At present,transduced primary fan was used widely in fossil-fuel power plant for energy saving.

The failure of a single primary fan may cause the stoppage of the whole power generating set, but the addition of a ventilation door each in the cold and hot pipelines makes it possible for the single primary fan to run with the coal grinder while the whole power generating set is operating non-stop with considerable economic results.

The output of pulverizer is raised by measures of changing segregator structure,heat wind data and flux,steel ball proportion.