Multiphase Flow Investigations in a Structured Packings Unit

Multiphase flow investigations in the structured packings unit

Rajesh K. Singh¹, Janine E. Galvin² and Xin Sun¹

¹Pacific Northwest National Laboratory, Richland, WA 99352, USA

²National Energy Technology Laboratory, Albany, Oregon 97321, USA

Post combustion carbon capture by solvent absorption has gained a significant commercial interest. The solvent absorption is carried out through counter-current gas liquid flow in a structured packed column.   The local hydrodynamics in the packing, in particular wetting of sheets is a key factor dictating overall efficiency of the column. The CFD modelling of such system is a complex problem due to a wide range of length scales.  In this context, multiphase flow simulation for wetting of sheets in the representative elementary unit (REU) of the structured packing can explain fundamental insights into meso-scale flow phenomenon. Specifically, Volume of Fluid (VOF) flow simulations are carried out over a wide range of parameters influencing the wetting dynamics such as solvent properties, contact angle, liquid load, etc. A scaling analysis for interfacial areas was performed based on simulation results since interfacial area actively participates in the transport phenomenon. Accordingly, a phenomenological correlation for interfacial area in terms of Kapitza number (Ka) is also proposed. The Kapitza number only depends on fluid properties and it decreases with increased solvent viscosity. The interfacial area decreases with increasing Ka number for a given contact angle and liquid load. Effects of contact angle are also extensively investigated at different Kapitza numbers and liquid loads. As expected, interfacial area decreases with increasing contact angle. Further, influence of liquid load at different contact angles and Kapitza number has also been explored.