Power Consumption and Gas-Liquid Mass Transfer Volumetric Coefficient in an Agitated Vessel with Pitched Wire-Gauze Blade Impeller under Aeration
Power consumption in a baffled agitated vessel with pitched wire-gauze blade impeller is measured over a wide range of Reynolds number in turbulent flow region, where the power consumption decreases with decreasing the wire-gauze blade angle. The power consumption without aeration is well correlated with the baffled condition parameter (<I>B</I><SUB>W</SUB>/<I>D</I>)<I>n</I><SUB>b</SUB><SUP>0.8</SUP>. The rotational speed to occur the gross circulation of gas <I>N</I><SUB>R</SUB> increased with the decrease of a blade angle <I>θ</I> for the upflow condition. In the operating conditions of the gross circulation flow of the gas back into the impeller (<I>N</I> > <I>N</I><SUB>R</SUB>) and the turbulent flow (<I>Re</I><SUB>d</SUB> > 200), the power consumption under aeration at the standard baffled condition <I>Np</I><SUB>g</SUB> is correlated with the modified equation by the blade angle <I>θ</I>, which was reduced to the power correlation for the wire-gauze impeller (<I>θ</I> = <I>π</I>/2). In the range of the rotational speed of <I>N</I> > <I>N</I><SUB>R</SUB> the power number under aeration is almost independent of the impeller position and the liquid flow direction through the impeller.<BR>The measured gas-liquid mass transfer volumetric coefficient for the pitched wire-gauze blade impeller <I>k</I><SUB>L</SUB><I>a</I> coincides well with the correlation of <I>k</I><SUB>L</SUB><I>a</I> for the wire-gauze impeller in lower viscosity liquid, whereas the former is smaller than the latter in higher viscosity liquid because of the lost of the wire-gauze blade effect.
- Journal of chemical engineering of Japan
Journal of chemical engineering of Japan 36(3), 333-338, 2003-03-01
The Society of Chemical Engineers, Japan