Experimental Study on the Combustion Characteristics of Pulverized Anthracite Preheated by Circulating Fluidized Bed

Based on the pulverized coal preheated to 800 ℃ in Circulating Fluidized Bed(CFB) with partial combustion under low excess air ratio,a bench-scale rig of combustion was constructed for investigating combustion characteristic of low volatile pulverized coal.The diameter of the CFB riser is 90 mm and the height 1500 mm.The diameter of the down-fired combustion chamber is 260 mm and the height 3 000 mm.Combustion experiment of pulverized anthracite coal with 6.67% volatile was carried out.Pulverized anthracite coal can be quickly and steadily preheated up to 800 ℃ in the CFB when the primary air is under 30% of theoretical air flow rate for combustion.After preheating process,the size of coal particle decreased significantly,the specific surface area and pore volume of coal particle increased significantly.High temperature coal particle burn quickly and steadily in down-fired combustion chamber.The combustion efficiency is 91.46%.