Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication

Measurement of dynamic liquid distributions in a fixed bed using electrical capacitance tomography and capacitance wire mesh sensor

Matusiak, B.; Da Silva, M. J.; Romanowski, A.; Hampel, U.


An intricate problem associated with fixed bed operation is liquid maldistribution, which denotes the fact that the liquid does not homogeneously flow through the bed. In a comparative study we evaluated two capacitance imaging methods - capacitance wire mesh sensor and electrical capacitance tomography (ECT) - with respect to their capability of measuring static and dynamic liquid holdup in a fixed bed. We performed experiments in a column of 100 mm diameter, packed with commercial porous Al2O3 catalyst particles. The column was operated at ambient pressure. Inlet flow of isopropanol from various point sources was applied at rates of 40 L/h and 60 L/h. The capacitance wire mesh sensor as an invasive instrument is able to disclose flow structures at higher spatial resolution and was therefore considered as the reference instrument for liquid holdup measurement. We found that both methods predict dynamic liquid holdup in the column in a similar way with only small systematic deviation. The results therefore prove that non-invasive electrical capacitance tomography can reliably measure cross-sectional dynamic liquid holdup in a fixed bed, even with a simple and fast linear back projection reconstruction algorithm.

Keywords: Wire-mesh sensor; ECT; Multiphase flow; Trickle bed; Liquid holdup; Liquid distribution