INTERFACIAL AREA AND GAS HOLDUP IN A BUBBLE-COLUMN REACTOR AT ELEVATED PRESSURES

dThe influence of pressure, liquid viscosity, and gas velocity on the gas holdup and specific gas-liquid interfacial area in a bubble column reactor has been studied. The 18.7 L reactor had an inner diameter of 15.6 cm with a dispersion height set equal to 3 times the diameter an d was operated at pressures between 0.1 and 6.6 MPa. By means of the c hemically enhanced absorption of CO2 in diethanolamine, the gas-liquid interfacial area in the reactor has been determined. The viscosity ha s been changed in the range from 1 to 9.4 mPa . s by adding ethylene g lycol to the mixture. It is determined that pressure has a small effec t on the gas holdup in pure water, whereas it shows a pronounced effec t for the more viscous liquids. This can be attributed to the influenc e of the increased pressure on the flow regime transition. For the mos t viscous liquid all interfacial area data were obtained in the fully heterogeneous regime. Here the interfacial area increased with increas ing pressure and was moderately affected by the gas velocity. For the less viscous liquids both pressure and gas velocity affect the interfa cial area; this influence depends on the flow regime. Therefore, the s tate of the flow regime has an important impact on the mode in which t he operating parameters affect the interfacial area.