Seamless mass transfer correlations for packed beds
bridging random and structured packings
Faïçal Larachi,* Stéphane Lévesque, Bernard P.A. Grandjean
Department of Chemical Engineering,
* Corresponding author: Phone: 1-418-656-3566 Fax: 1-418-656-5993.
Abstract: A unifying correlative approach for the gas-liquid mass transfer in both structured- and random-packing containing towers was developed based on a two-correlation kernel. Two databanks consisting of 861 experiments for structured packings and 4,291 experiments for random packings were merged, and concerned the volumetric local and overall gas- and liquid-side mass transfer coefficients kGaw, kLaw, KGaw, KLaw, the effective gas-liquid interfacial area, aw, and the height equivalent to a theoretical plate, HETP. The three-phase systems were representative of absorption, desorption and distillation applications. Two correlations have emerged, the first to evaluate the local gas- or liquid-side mass transfer coefficient (kg), the second to correlate the effective gas-liquid interfacial area (aw). A reconciliation method was used to calibrate and validate the two-correlation kernel (kg,aw) owing to a broad domain of applicability and embracing indifferently both structured- and random-packing columns. The results proved satisfactory and statistical analysis yielded, respectively, 22.1 % and 17.6 % for the mean and standard deviation for the absolute relative error (ARE) regarding the mass transfer parameters applicable to structured packings. These correlations had also the capacity to predict the same parameters for the random packings with a mean and standard deviation for ARE, respectively, of 26.3 % and 24.4 %.
You can get the awk-stra.zip file that contains an Excel worksheet simulator to compute kGaw, kLaw, KGaw, KLaw, aw, and HETP.
- Excel worksheets simulators for Trickle-bed or Flooded Bed reactors or for predictions of mass transfer in randomly packed towers operations
The neural correlation was developped with the software NNFit