a down-flow hanging sponge (dhs) reactor has been developed for sewage treatment, mainly in developing countries. this novel reactor employs polyurethane sponge material as a support medium, which promises a proliferation of a large amount of biomass, offering excellent pollutant removal capability. three types of sponge medium were evaluated with respect to water distribution and oxygen mass t...

The influence of power consumption on the volumetric mass transfer coefficient was studied in a 5 liter stirred tank bioreactor during cultivation of a recombinant Chinese Hamster Ovary (CHO) cell line, which requires low aeration and mixing intensity. Under these conditions and at high cell concentrations, oxygen mass transfer coefficient and consequently volumetric oxygen mass transfer rate w...

Overall liquid side volumetric mass transfer coefficient kLa was determined experimentally for cocurrent Taylor flow moving upwards in a glass tube of an internal diameter of 3mm. Experiments were performed for physical absorption of oxygen in 20% aqueous solution of ethanol. Shadowgraph technique was deployed for precise measurements of bubble lengths and velocities. Experimental values of vol...

The effects of temperature, agitation and aeration on glycoprotein GP-1 production by Streptomyces kanasenisi ZX01 in bench-scale fermentors were systematically investigated. The maximum final GP-1 production was achieved at an agitation speed of 200 rpm, aeration rate of 2.0 vvm and temperature of 30 °C. By using a dynamic gassing out method, the effects of agitation and aeration on volumetric...

Gas holdup, mixing, liquid circulation and gas–liquid oxygen transfer were characterized in a large (∼1.5 m3) draft-tube airlift bioreactor agitated with Prochem® hydrofoil impellers placed in the draft-tube. Measurements were made in water and in cellulose fiber slurries that resembled broths of mycelial microfungi. Use of mechanical agitation generally enhanced mixing performance and the oxyg...

in this study, the diffusivity and volumetric mass transfer coefficients for the extraction of β-carotene from crude palm oil using co2 solvent in supercritical fluid were determined in the pressure range of 7.5-17.5 mpa and temperature range of 80-120 ºc. for this purpose, a statistical method was applied in order to minimize the number of experiments required. the volumetric mass transfer coe...

In this study, the diffusivity and volumetric mass transfer coefficients for the extraction of β-carotene from crude palm oil using CO2 solvent in supercritical fluid were determined in the pressure range of 7.5-17.5 MPa and temperature range of 80-120 ºC. For this purpose, a statistical method was applied in order to minimize the number of experiments required. The volumetric ma...

In this paper, we present an experimental study on mass transfer of oxygen into water in an oscillatory baffled column (OBC). The objective of this work is to establish the contribution of individual parameters, such as the size of bubbles and the gas holdup, to the overall volumetric mass transfer coefficient (kLa). Our results show that the gas holdup is the most important factor. The liquid-...