Modeling of Gas−Liquid Mass-Transfer Limitations in Slurry Olefin Polymerization

A model of gas to liquid mass transfer in a stirred laboratory reactor was developed with the purpose of controlling mass-transfer limitations in kinetic studies of olefin polymerizations. Renewing the liquid surface is controlling the mass transfer. Generally, two different scales of eddies can be envisaged to be responsible for the renewal: at low stirring rates, the mean liquid flow is the controlling mechanism; at high stirring rates, small-scale turbulence provides the renewal. The change is at a specified turbulent Reynolds number. The model for the high Reynolds number region is based on an established mass-transfer relationship from the literature. For low Reynolds numbers, a new correlation is developed based on literature studies of the liquid circulation velocity at the gas−liquid interface. The model predictions are compared with experimental data for propene polymerization in decane. It was found that the small-scale turbulence model was most appropriate, and fitted the data within a factor 2. The models are theoretically founded and form a basis for the control of mass-transfer effects in the measurements of kinetic data.