Interface Mass Transfer in Reactive Bubbly Flow: A Rigorous Phase Equilibrium-Based Approach

Abstract

In this work, the driving force of interfacial mass transfer is modeled as deviation from the gas-liquid equilibrium, which by assumption is thought to exist at the interface separating the gas and liquid phases. The proposed mass transfer model provides a flexible framework where the phase equilibrium description in the driving force can be substituted without difficulties, allowing the mass transfer modeling of distillation, absorption/stripping, extraction, evaporation, and condensation to be based on a thermodynamically consistent phase equilibrium formulation. Phase equilibrium by the Soave-Redlich-Kwong equation of state (SRK-EoS) is in this work compared to the results of the classical Henry’s law approach. The new model formulation can predict mass transfer of the solvent, which Henry’s law cannot. The mass transfer models were evaluated by simulating a single-cell protein process operated in a bubble column bioreactor, and the solubilities computed from the SRK-EoS and Henry’s law were in qualitative agreement, albeit in quantitative disagreement. At the reactor inlet, the solubility of O2and CH4was 150% higher with the SRK-EoS than with Henry’s law. Furthermore, the SRK-EoS was computationally more expensive and spent 10% more time than Henry’s law.