EINFLUSS DER KONSTRUKTION UND PROZESSFÜHRUNG AUF DAS BETRIEBSVERHALTEN VON BLASENSÄULENREAKTOREN MIT ÄUSSERER SCHLAUFE

Abstract

Cell growth and product formation as well as productivity of aerobic cultivations are strongly influenced by the oxygen transfer rate. Strategies for construction of effective tower reactors with an outer loop and their operation were developed by means of measurements with model media and cultivations of Hansenula polymorpha. The coalescence behavior strongly influences this strategy. For media with strong coalescence suppressing character a high energy dissipation rate should be used in a limited volume near the aerator. In coalescence promoting media, the energy dissipation rate should be uniformly distributed along the column. When employing columns with proper stage heights this strategy can be realized. Antifoam additives significantly reduce the oxygen transfer rate. This reduction can be overcompensated by using multistage columns with low stage heights. Biomass productivity can be increased and specific power input can be reduced in these reactors with regard to single-stage reactors which are operated without antifoam agents.