Visualisation of flow pattern and measurement of liquid distribution in a random packed column using electrical resistance tomography (ERT)
thesisposted on 23.05.2021, 09:45 by Nazar Aoda
The aim of this research is to use Electrical Resistance Tomography technique (ERT) to measure factors that affect local mass transfer at various axial locations in a random packed column with diameter 0.3m and bed height 150cm filled with 2 cm plastic spheres. These factors are: liquid maldistribution, velocity profiles, and flow pattern. The system was designed to run in a trickling down-flow mode and a full liquid up-flow mode. Experiments were performed at flow rates of 3, 6, and 9 gpm (or 0.27 x 10⁻², 0.54 x 10⁻² and 0.8 x 10⁻² m³/m² s) and under normal operating conditions of 25C° and atmospheric pressure. The liquid maldistribution factors were measured via ERT technique and the conventional liquid collection method. Both measurements were conducted at various fluid flow rates at different bed heights. The results of ERT were in very good agreement with the conventional method. The standard deviation values were 17% and 21% at flow rates 3 and 6 gpm respectively. The numerical values of velocity for full liquid up flow at 3 gpm were 0.83cm/s, 1.2cm/s, 1.2 cm/s and 1.11 cm/s for different heights of 30, 60 and 90 cm respectively and the numerical values of velocity for trickle down flow at 3 gpm were 16.5 cm/s, 22.5 cm/s and 24 cm/ for different heights of 30, 60 and 90 cm respectively. The values of the liquid maldistribution factor for flow rate 3 gpm were 0.43 (30cm), 0.33(60cm) and 0.30 (90cm) and for flow rate 6 gpm were 0.33(30cm), 0.27(60cm) and 0.22 (90cm). By comparison with findings of many studies conducted on liquid distribution in packed bed column, a good agreement was observed on the relation of Mf and flow rates and bed heights.