Modelling and optimization of transverse flow hollow fibre membrane contactors for the recovery of dissolved methane from anaerobic effluents

Abstract

The desorption of dissolved methane (D-CH4) from anaerobic effluents with transverse flow hollow fibre membrane contactors (HFMC) was mathematically modelled with sweeping gas to allow the recovery of a CH4-rich waste gas. A new 2D finite-element model of a HFMC was calibrated and validated with experimental data, and compared to other “black-box” models described in the literature. The developed model showed a better experimental fitting, though at a much higher mathematical complexity. In contrast to the black-box models, the 2D finite-element model allowed the study of the internal desorption of D-CH4 along different transverse-flow HFMC configurations. It was used to optimize the HFMC scaling up for this application, by considering the energetic balance of the process. It was found that non-baffled HFMCs seemed to provide more energetically favourable conditions for this application than the baffled units. In addition, non-baffled HFMCs seemed to be energetically optimised in shorter units (with larger diameters), whereas the opposite was found for the baffled units.