In order to comprehensively utilize the semi-coke resources generated by coal pyrolysis

field test about large proportion co-firing of semi-coke was carried out on a 300 MW pulverized coal boiler

and the boiler performance as well as the NO_x emission characteristics were investigated under different conditions. The results show that

the semi-coke had good ignition performance and could improve the combustion characteristics of the raw coal. By adopting the blending method of "grinded by different mills

separated storage and stratified mixing in the furnace"

the boiler with semi-coke's co-firing proportion of 50% could realize safe and stable operation. At 300 MW

when the blending proportion of semi-coke reached 50%

the boiler efficiency increased from 90.36%(before co-firing) to 92.79%

and the NO_x emission mass concentration decreased from 493.85 mg/m~3(before cofiring) to 435.86 mg/m~3. Co-firing large proportion of semi-coke can enhance the pulverized coal boiler's efficiency and reduce the NO_x emission mass concentration

but increase the temperature at the furnace outlet slightly as well as the amount of cooling water.