Differing findings on the volumetric mass transfer coefficients k(L)a in CMC solutions in bubble column bioreactors have been reported in the literature. Therefore, oxygen mass transfer was studied again in CMC solutions in a 14-cm-i.d. x 270-cm-height bubble column using different spargers. The k(L)a values were determined along with the dispersion coefficients by fitting the prediction of the axial dispersed plug model with the experimental oxygen concentration profiles in the liquid phase. Surprisingly, the obtained liquid phase dispersion coefficients for CMC solution are higher than one would expect from correlations. The k(L)a data depend largely on the flow regime. In general, they are lower than those reported in the literature. The data for developing slug and established slug flow are dependent on the gas velocity and the effective viscosity of the solution and can br correlated by a simple correlation. This correlation describes k(L)a values measured on fermentation broth of Penicillium chrysogenum with striking agreement.

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Fischer-Tropsch (FT) synthesis was studied on a specially prepared /Fe catalyst in the slurry phase. Compared to classical K promoted Fe precipitation catalysts, the /Fe catalyst gives higher yields of C2 to C4 olefins, i.e., about 60 g/Nm3 synthesis gas converted. The product slate follows the Schulz-Flory distribution and is little influenced by operational conditions. From the experimental conversion data, rate constants for overall synthesis gas conversion were calculated.

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