煤炭转化2017，Vol.40Issue(4)：18-22,80,6.
非等物质的量反扩散对流化床内煤颗粒燃烧的影响
Effect of Non-equal Amount-of-substance Counter Diffusion on Coal Particle Combustion in Fluidized Beds
摘要
Abstract
Effect of the non-equal amount-of-substance counter diffusion on the mass transfer process within the boundary layer at the burning coal particle surface in the dense phase of fluidized beds was discussed theoretically.The mathematic correlations between the mass transfer coefficients kg and kg,em as well as between the dimensionless numbers Sh and Shem were also proposed.It indicate that the microscopic gas flow within the boundary layer caused by the non-equimolar counter diffusion inhibits the O2 molecules from traveling to the coal particle surface.The microscopic gas flow becomes stronger with the increasing molar concentration ratio of CO and CO2 within the boundary layer,which results in higher mass transfer resistance.As the O2 volume fraction gradient in the boundary layer declines,the inhibition of the microscopic gas flow on the mass transfer process becomes stronger as a result of the decrease of the driving force for the O2 molecules diffusion.关键词
煤颗粒/燃烧/流化床/传质/密相区/非等物质的量反扩散Key words
coal particle/combustion/fluidized bed/mass transfer/dense phase/non-equal amount-of-substance counter diffusion分类
化学化工引用本文复制引用
晁俊楠..非等物质的量反扩散对流化床内煤颗粒燃烧的影响[J].煤炭转化,2017,40(4):18-22,80,6.基金项目
国家高技术研究发展计划(863)项目(2015AA050505). （863）
