Modeling of VOC mass transfer in two-liquid phase stirred tank, biotrickling filter and airlift reactors

A modeling framework based on general mass balances and transfer equations was here developed in order to compare the hexane mass transfer performance of two-liquid phase stirred tank reactor (SIR), airlift (ALR) and biotrickling filter (BTF) using silicone oil as model non-aqueous phase under abiotic conditions. This modeling approach resulted in an isomorphous expression for all configurations consisting of a parameter beta*(s) (characterizing the maximum fraction of VOC transferable from the gas to the aqueous phase) and the gradient established between the gas and the aqueous phase. The models were validated against experimental data (at empty bed residence times, EBRT, of 120, 60 and 40 s) exhibiting an overall goodness of fit of 0.98, 0.98 and 0.70 for the two-liquid phase STR, BTF and ALR, respectively. The two-liquid phase BTF exhibited the maximum value of beta*(s) (0.87-0.58), followed by the STR (0.77-0.49) and the ALR (0.23-0.19). Finally, a sensitivity analysis conducted in the two-liquid phase BTF showed that was more sensitive to changes in recirculating liquid flow rate than in the EBRT, confirming that the liquid flow rate is a key operational variable in BTF systems. (C) 2011 Elsevier B.V. All rights reserved.