Mass Transfer Phenomena and Hydrodynamics in Agitated Gas-Liquid Reactors and Bubble Columns at Elevated Pressures: State of the Art

All important studies on the influence of pressure on mass transfer phenomena in gas-liquid systems and reactors are reviewed critically. Points of agreement and conflict are indicated and discussed. It is concluded that: (1) the initial bubble size at a single orifice decreases with increasing pressure; (2) the gas-phase mass transfer coefficient kG is inversely proportional to the pressure to the power n, where n depends on the mass transfer mechanism; (3) the liquid-phase mass transfer coefficient k, is not influenced by pressure; (4) the gas hold-up .so in bubble columns increases with increasing pressure. However, insufficient data on the influence of the operating pressure on the interfacial areas in gas-liquid contactors are available.