煤颗粒的形貌特征对流化床燃烧室设计的影响

煤颗粒的形貌特征是流化床锅炉设计的重要基础数据。设计时颗粒平均粒径用ｄｐ＝Ｘｉｄｉ来计算。形状因子不同则ｄｐ不同，且阿基米德数Ａｒ和临界流化风速ｕｍｆ甚至流化床内传热系数也发生变化。该文以几种固体燃料为例研究了煤颗粒的形状因子及其对流态化、床内传热的影响。研究表明，对宽筛分煤不宜推荐狭窄的值范围。有必要建立形状因子的分布曲线，设计时采用下式计算平均粒度ｄｐ＝ｉＸｉｄｉ，以免造成传热面积设计过大、锅炉投运后床内埋管被迫割除的结果。图３表１参８

The Influence of Coal Grain Shape Characteristics on Design of Fluidized Bed Furnaces

The coal grains’shape factor  and its influence on fluidization and heat transfer in the bed is being studied by taking a few kinds of solid fuels as samples.Study results show,that it would be better not to recommend a narrow range of  if screening is done with a coarse screen.It is necessary that a distribution curve of the shape factor  be provided and the calculated mean grainularity d p=Σ i x i d i be used for design,to avoid heat transfer surfaces being designed oversized and some submerged pipes having to be cut away after commissioning.