Three kinds of coal differed from fineness were burned in a laboratory-scale drop tube furnace for combustion test,and an 8-stage Andersen particle impactor was employed for sampling the primary particulate matter(PM),in order to study coal fineness effect on primary PM features during pulverized coal combustion.

Two models respectively describing the pulverizing unit cost and the coal fineness of the middle-storage pulverizing system are established by means of the least-square support vector machine,and the combinational genetic algorithm is adopted to seek the optimal operation parameters for the minimum unit consumption in different operating modes.

Since the next half year of 2004,coal fineness of JiuJiang stage three project 2×350MW units gradually began increasing, This brought a lot of problem to production, This paper individually analyzes different factors that influences coal dust milling, finds the reason causing coal fineness overproof and works out measures to reduce coal fineness.

Through improving and debugging the firing system,optimizing the opera-tion adjustment and reducing the fineness of pulverized coal,the combustible matter in the fly ash was reduced to about 5.

If the dynamic separator,powder mixture temperature 150℃, mill capacity sufficient margin is designed in the low-volatile coal pulverizer system,the fineness of pulverized coal,uniformity,a good fire and combustion stability can be assured.

In monitoring the combusting process of boiler, we obtained measures of reducing combustibles in fly ash and ash to improve efficiency of boiler by detailed detailedly analysing the ratio of the first and second wind speed, fineness of pulverized coal, coal type and so on.

Rational choice of PC granularity is of an important measure to decrease comprehensive cost of generating power in an electric power plant;