Hydrodynamik in Blasensäulen – Messung von relativem Gasgehalt und Blasengröße

In bubble column reactors mass transfer kinetics are determined by local hydrodynamic processes (bubble formation, velocity, coalescence, break‐up, etc.). For a better understanding of the influence of pressure and particle load on these processes, a measurement system for detection of local bubble size distributions in opaque bubbly flows is needed. Therefore, in this work an optical needle probe was applied in a bubbly flow. In a first step, the needle probe was validated by means of single‐bubble measurements. The measurement technique shows high potential for application in more complex and opaque systems.     

Zur Ermittlung von Stoffübergangszahlen auf der Basis von Gelöstsauerstoff-Messungen

Determination of mass transfer coefficients on the basis of dissolved-oxygen measurements . Sources of error in the dynamic and the stationary method for determination of mass transfer coefficients are discussed on the basis of experimental results obtained in bubble columns. In particular, the delayed electrode response, the resistance in the liquid film, bubble contacts of the electrode, and the influence of very small bubbles encountered in viscous media have to be considered.