Effect of particle lyophobicity in slurry bubble columns at elevated pressures

The influence of particle lyophobicity on gas hold-up, homogeneous to churn-turbulent regime transition, and gas–liquid mass transfer is investigated in a 0.15 m diameter slurry bubble column at pressures from 0.1 to 1.3 MPa. An air/nitrogen mixture is bubbled through 0–3 vol% slurries of activated carbon particles or silica particles suspended in demineralized water or organic oil Isopar M. The gas hold-up and flow regime transition point are not influenced by the presence of lyophilic particles. Lyophobic particles shift the regime transition to a higher gas velocity and cause foam formation. The gas–liquid mass transfer coefficient is proportional to the gas hold-up for all investigated slurries and is not affected by the particle lyophobicity and the operating pressure. A correlation is presented to estimate the gas–liquid mass transfer coefficient