Convective drying of sludge cake

被引:0
作者
Jianbo Chen
Xiaofeng Peng
Yuan Xue
Duujong Lee
Chingping Chu
机构
[1] Tsinghua University,Thermal Engineering Department
[2] National Taiwan University,Department of Chemical Engineering
来源
Journal of Thermal Science | 2002年 / 11卷
关键词
sludge; convective drying; visualization;
D O I
暂无
中图分类号
学科分类号
摘要
This paper presented an experimental study on convective drying of waste water sludge collected from Beijing GaoBeiDian Sewage Treatment Plant, particularly on the correlation between the observed shrinkage dynamics of sludge cake and the drying curve. During the initial stage of drying the process resembles to that of a particulate bed, in which moisture diffuses and evaporates at the upper surface. Conventional drying theory assuming a diffusion-evaporating front interprets this period of drying. Consequently, owing to the very large shrinkage ratio of the dried cake, cracks emerges and propagates on and within the cake body, whence inducing evaporating channel that facilitates the water removal. This occurrence compensates the reduction of surface area for evaporation, whence extending the constant-rate period during the test. Afterwards, the cracks meet with each other and form isolated cake piles, while the subsequent drying occur mainly within these piles and the conventional theory fails. The transition between the drying on a plain cake layer and that on the isolated piles demonstrates the need to adopt distinct descriptions on these two regimes of drying for the sludge cake.
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页码:277 / 282
页数:5
相关论文
共 8 条
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[2]  
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