The property of coal particles has very large influence upon the formation behavior of ash and slag in the combustion process of CFB boilers.The Yima bituminous coal has been divided into several categories according to the coal particle size and its ash content.The test study on the influence of coal particle size upon the formation behavior of ash and slag has been carried out in a small CFB reaction furnace.Results show that the influence of coal particle distribution upon the particle size distribution of bottom slags is gradually increased as the the ash content in coal is increased

the share of bottom slag is reduced as the coal particle size is increased

however

the reduced magnitude is decreased as the ash content in coal is increased.The burn-away rate of coal particles with low ash content hasn't remarkable regularity with the coal particle size

but the burn-away rate of coal particles with high ash content is reduced as the coal particle size is increased.