Abstract: According to the characteristics of pulverizer rejects, the advantages and disadvantages of the reduction of pulverizer rejects are analyzed, particularly with the emphasis on the combustion efficiency of the pulverizer rejects returned to the furnace, the impact of the sulfur content of pulverizer rejects on high-temperature corrosion and the power consumption by the milling system and the desulfurization system. Through calculation, the impact of these factors on the reduction is studied, which concludes that pulverizer rejects are a kind of low quality fuel with low heat value, high sulfur content, poor grindability, bad inflammability and low combustion efficiency. When pulverizer rejects return to the furnace, not only the power consumption of the milling system and the desulfurization system will increase, but also the high-temperature corrosion in the furnace and the low-temperature corrosion in the air heater will deteriorate, which will result in negative comprehensive benefits. Therefore, reducing the quantity of pulverizer rejects needs more attention and carefulness. Quantitative studies on the economics of the utilization of pulverizer rejects should be enhanced to instruct power plants through the quantity control of pulverizer rejects in milling systems.

Key words: pulverizer reject, burnout, boiler thermal efficiency, milling system, desulfurization system, power consumption, unburned combustibles in fly ash