Alleviating mass transfer limitations in industrial external-loop syngas-to-ethanol fermentation

Mass transfer limitations in syngas fermentation processes are mostly attributed to poor solubility of CO and H2 water. Despite these assumed limitations, a process has recently been commercialized. Using large-sale external-loop gas-lift reactors (EL-GLR), CO-rich off-gases converted into ethanol, with high mass performance (7–8.5 g.L-1.h−1). However, when applying established correlations, much poorer is predicted (0.3–2.7 We developed CFD model, validated on pilot-scale data, provide detailed insights hydrodynamics large-scale EL-GLR. As produced ethanol could increase gas hold-up (+30%) decrease the bubble diameter (≤2 mm) compared air–water mixtures, we found our model that volumetric coefficient (650–750 h−1) capacity (7.5–8 g.L-1.h−1) for feasible. Thus, typical encountered systems can be alleviated syngas-to-ethanol process.