Chemical Engineering Science, Vol.57, No.15, 2987-2994, 2002
Influence of viscosity and surface tension on performance of gas-liquid contactors with ejector type gas distributor
Effect of the liquid-phase viscosity (0.7-25 mPa s) and surface tension (33-65 mN m(-1)) on hydraulic and mass-transfer characteristics in a bubble column with an up-flow ejector-type gas distributor was studied. The coalescent character of the aqueous batches was changed by addition of a polymeric thickener, sucrose and an alcoholic foam breaker. Mass transfer was studied using steady-state physical absorption of air. Better performance of the ejector with swirl body for all tested liquid batches was achieved. Gas hold-up in the bubble column increased with increasing viscosity and surface tension in all batches. Mass-transfer coefficient in the ejector decreased with increasing viscosity by 60% maximally in the maximum viscous coalescent batch. It was correlated within +/-10% using the gas monodispersion model. Mass-transfer coefficient in the column decreased with increasing viscosity by 30% maximally in the same coalescent viscous batch. It was correlated with large relative error, +/-27%.
Keywords:ejector gas distributor;hydrodynamics;mass transfer;multiphase reactors;surfactant;viscous liquids