摘要
在直径为２６７ｍｍ的５Ａ分子筛固定床上，采用稳态有限源示踪技术，利用计算机数据采集系统，测定了不同流速下床层内部截面上示踪气体的浓度分布数据。并分别利用稳态有限源和稳态点源示踪条件下扩散模型的解析解，获得床层内的径向扩散系数值。结果表明，两种处理方法所获得的径向扩散系数值大致相等，且在实验条件范围内，当Ｒｅ数较小时，径向扩散系数值与分子扩散系数值相当，随着Ｒｅ数的增加，径向扩散系数值逐渐增大，最后几乎与流速成正比。文中还讨论了轴向扩散系数值对径向扩散系数计算结果的影响。
adial disporsion was measured in a 267mm I.D.column,packed with 5A molecular sieve andthrough which air flowed.Methane,as a tracer,was introduced steadily into the center of the bed andits concentration were detected at different radial position of the level(0.31m downstream)by usinga gas concentration collecting system. The radial dispersion coefficients were calculated from the databy using a finite source solution to the dispersion model.Under experiment condition,the simpler point source solution would give about the same results.It was shown that,at low Renolds Numbers the radial dispersion was effected mainly by molecular dif-fusion,but at high Reynolds numbers eddy diffusion predominated.Furthermore,the importance ofaxial dispersion was studied by computing the effect of the magnitude of axial diffusivity on the radialdiffusivity.
出处
《化学工程》
CAS
CSCD
北大核心
1994年第6期37-41,45,共6页
Chemical Engineering(China)
基金
国家自然科学基金
关键词
固定床
扩散模型
浓度分布
径向扩散系数
fixed bed,dispersion model,concentration distribution,radial dispersion
