采用基于将煤粉在CFB(循环流化床)低空气当量比下部分燃烧,使其预热到800℃以上再进行燃烧的新工艺,研究无烟煤煤粉的稳燃特性。为此,搭建了基于CFB(循环流化床)预热的无烟煤燃烧系统,其中CFB(循环流化床)提升管直径90mm,高度1 500mm;下行燃烧室直径260mm,高度3 000mm。用挥发分含量为6.67%的无烟煤粉为燃料的试验表明:在CFB(循环流化床)空气当量比低于0.3条件下,可持续稳定的将无烟煤粉预热到800℃以上;煤粉经预热后粒径显著减小,比表面积、总孔体积显著增大;高温预热煤粉在下行燃烧室内燃烧迅速、并在1 100℃温度下能够稳定燃烧,燃烧效率达到91.46%。
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%.