Measurement of Volumetric Mass Transfer Coefficient in Bubble Columns

Abstract

Abstract:The paper presents a brief overview of experiments on volumetric mass transfer coefficient in bubble columns. The available experimental data published are often incomparable due to the different type of gas distributor and different operating conditions used by various authors. Moreover, the value of the coefficient obtained experimentally is very sensitive to the particular method and to the physical models used in its evaluation. It follows that the Dynamic Pressure Method (DPM) is able to provide physically correct values not only in lab-scale contactors but also in pilot-scale reactors. However, the method was not correctly proven in bubble columns. In present experiments, DPM was employed in a laboratory-scale bubble column with a coalescent phase and tested in the pure heterogeneous flow regime. The method was successfully validated by the measurements under two different conditions relevant to the mass transfer. First, the ideal pressure step was compared with the non-ideal pressure step. Second, the pure oxygen absorption was compared with the simultaneous oxygen-and-nitrogen absorption. The obtained results proved that DPM is suitable for measuring the mass transport in bubble columns and to provide reliable data of volumetric mass transfer coefficient.

Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

“…Literature values for k sol and k fre span large ranges that cover our best-fit parameters. Comparison of best-fit k sol and k fre indicates O 2 reacts more quickly with free compared to solid phase Fe­(II), in agreement with trends for O 2 reacting with aqueous Fe 2+ versus reduced nontronite reported by Zeng et al Literature values for k oe span a relatively small range (0.001 to 0.06 s –1 , Table S3), and the value depends on the degree of sample mixing. − Our value is relatively small because sample bottles were gently oscillated at 220 rpm on a shaker, while samples were rapidly mixed in prior work.…”

Experimental analysis of the effects of liquid phase surface tension on the hydrodynamics and mass transfer in a square bubble column

“…and liquid properties (viscosity, presence of ions inhibiting coalescence, or surfactants adsorption, etc.) [29,30]. Regarding the specific effect of surfactants, it is reflected in the increase in the bubble drag force coefficient and the decrease in the bubble rise velocity since these substances tend to accumulate at the bubble gas−liquid interfaces [31].…”

Small-Scale Bioreactor for Sterile Hydroponics and Hairy Roots: Metabolic Diversity and Salicylic Acid Exudation by Hairy Roots of Hyoscyamus niger

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