The liquid?solid extraction process of caprolactam (CL) in nylon 6 particles was investigated by packed bed semi-continuous experiments under the conditions of industrial interest. Based on the assumption that the CL concentration profile inside particles conformed to parabolic profile during the extraction, the external mass transfer coefficient model was developed. The results showed that in the range of temperature 65~95℃ and liquid velocity 0.27~2.71 mm/s, the liquid?solid extraction process of CL could be significantly accelerated by the increase of either temperature or liquid velocity. The external mass transfer coefficient model was adapted to reproduce the experimental data under the dimensionless time larger than 0.15. Through normalizing the external mass transfer coefficients, a correlation of Sh, Sc and Re, which could be used to predict the CL external mass transfer coefficient in the industrial extraction tower, was acquired.
Chunxi QIN Zhenhao XI Ling ZHAO
. External Mass Transfer Coefficient of Caprolactam in Nylon 6 in Liquid-Solid Extraction Tower[J]. The Chinese Journal of Process Engineering, 2018
, 18(1)
: 75
-81
.
DOI: 10.12034/j.issn.1009-606X.217261
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