Abstract: Abstract:In regard to condition of high carbon content in fly ash and low boiler efficiency caused by burning complex coal type and rather poor quality coal in the 700MW supercritical unit boiler of Fengcheng PhaseⅡPower Plant, therefore, combustion adjustment tests have been done to change the condition, such as change fineness of pulverized coal, change primary air flow, and change combination mode of coal mill etc. Optimization has been done for boiler operation mode in accordance with tests result, including choose coal type properly, confirm optimum air flow of coal mill, adjust outlet oxygen volume of boiler in time, increase loading oil pressure of coal mill grinder roll and so on. After optimization, the boiler efficiency has been increased greatly, and decreased station service power consumption rate and carbon content in fly ash, thus achieved favorable economic benefit.

Key words: Keywords:supercritical boiler, boiler efficiency, carbon content in fly ash, pulverizing system, optimizing operation, combustion adjustment