Interfacial areas and gas hold-ups were determined at pressures of up to 1.7 MPa in a glass vessel, 88 mm in diameter and of standard geometry. Superficial gas velocities between 0.25 and 2.0 cm/s were used and the stirring speed varied between 4 and 30 rps. The interfacial areas were determined by the chemical method, using the model reaction between CO2 and aqueous diethanolamine (DEA). Hold-ups were determined by observation of differences in height. In contrast to literature indications, the gas hold-up was found to be independent of reactor pressure. This is also true for the interfacial area.
Oyevaar, M., Zijl, A., & Westerterp, K. R. (1988). Interfacial areas and gas hold-ups at elevated pressures in a mechanically agitated gas-liquid reactor. Chemical engineering and technology, 11(1), 1-10. https://doi.org/10.1002/ceat.270110102