无烟煤细颗粒在300MW CFB锅炉内停留时间分析

An Analysis of the Residence Time of Anthracite Fine Particles in a 300 MW Circulating Fluidized Bed Boiler

通过分析我国首台引进型300MWCFB锅炉燃煤特性与结构特点,研究了CFB锅炉燃烧系统各部分的具体结构对无烟煤颗粒炉内停留时间的影响。探讨了在各分燃烧系统内停留时间的计算方法,定量计算了300MWCFB锅炉BMCR工况下细颗粒的炉膛内停留时间和燃尽时间。研究发现:返料管内为还原性气氛,无烟煤颗粒与高温物料在返料管内混合,时间长达2min,热解过程主要发生在该阶段,这种结构极大地促进了无烟煤颗粒的着火和燃尽;炉膛是煤燃烧的主要区域,大颗粒主要在密相区流态化燃烧,直至燃尽;细颗粒燃烧主要发生在稀相区,其在该锅炉炉膛稀相区的停留时间大于其燃烧所需时间;具有一定的下倾角和凹槽的分离器入口烟道和排气中心筒底部缩口并偏置的绝热旋风分离器保证绝大部分的细颗粒返回炉膛,确保细颗粒在炉膛的停留时间超过其燃尽时间;以上结构形式是确保锅炉飞灰含碳量低的根本圆心,这为更大容量CFB锅炉的设计奠定理论基础。

Through an analysis of the coal combustion characteristics and structural features of a 300 MW circulating fluidized bed (CFB) boiler first introduced by China,studied was the influence of the specific structures of various parts of the boiler combustion system on the in-furnace residence time of anthracite particles. The method for calculating the residence time in various combustion subsystems was explored,and the in-furnace residence time and burn-out duration of the fine particles in the 300 MW CFB boil...