Predicting gas-liquid mass transfer rates in reactors using a bubble parcel model

•A novel coarse-graining approach for modelling high gas flow rate fermenters is presented.•The suitability of this approach is characterized using a bubble collision ratio.•Mass transfer and gas hold-up predictions agree with measured values of identical systems.•The approach presents an order-of-magnitude reduction in runtime, compared to a bubble-by-bubble tracking. A parcel-based approach for predicting mass transfer in gassed bioreactors is presented. Predictions from this parcel model, which handles bubble break-up and coalescence implicitly, are compared directly to measured data and predictions from full-fidelity discrete bubble models. Guidance for determining when this coarse-graining approach is acceptable, as a function of the vessel operating conditions, is presented. When the approach is appropriate, the parcel-based model can present order-of-magnitude reductions in computational runtime with minimal loss in physical fidelity.