Lu Han and Muthanna H. Al-Dahhan A gaseous tracer technique and procedures were developed and implemented to measure the axial dispersion of gas phase in a slurry bubble column reactor using air-water-glass beads (100ìm). Residence time distribution curves were obtained by measuring the response of gaseous tracer pulse input. The gas phase axial dispersion coefficient, Dg, was determined from m...

Oxygen gas-liquid mass transfer coefficient was measured in a gas-induced pulsating flow bubble column. Pulsating amplitude had a great influence on kla under pulsating state of equal base flow and pulsating flow, which was enhanced up to 30 % compared with that under steady state; however, it had a negative effect on mass transfer under a fixed low base flow. It was also found that kla had a n...

The semicontinuous and continuous production of pharmaceutically useful ergot peptides with immobilized Claviceps purpurea could be demonstrated. A key aspect was the presence of high concentrations of CaCl(2) (96.9 mM) to give marked prolongation of the productive phase, and cultivation in a bubble column reactor became possible. Restriction of the phosphate supply avoided an otherwise problem...

We introduce a miniature gate valve as a readily implementable strategy for actively controlling the flow of liquids on-chip, within a footprint of less than one square millimetre. Bubble gates provide for simple, consistent and scalable control of liquid flow in microchannel networks, are compatible with different bulk microfabrication processes and substrate materials, and require neither ele...

The objective of this paper is to develop a reliable, yet-simple, correlation for the liquid phase axial dispersion coefficient Dax,L in bubble column reactors. In order to develop this correlation we carried out measurements of the centre-line liquid velocity VL(0) and Dax,L in bubble columns of diameter DT=0.174, 0.38 and 0.63 m with the air-water system. The measurements were performed in th...

Extended abstract Understanding the complexity of the fluid dynamics in bubble column and airlift reactors is important due to their application in the chemical and bioprocess industries. So the objective of this research was to develop a fundamental understanding of the hydrodynamics and interactions with the chemistries involved in the bubble column reactor to maximize overall efficiency for ...

In this analysis, based on the bubble point method, a physical model was established clarifying the interactions (mass and heat) between the species present in the streams in circulation in the column. In order to identify the externally controlled operating parameters, the degree of freedom of the column was determined by using Gibbs phase rule. The mathematical model converted to Fortran code...