Paweł Niegodajew

Modelling liquid redistribution in a packed bed

The paper is devoted to the computational fluid dynamics (CFD) simulation of liquid spreading process in a packed bed. The volume of fluid (VOF) approach was applied to simulate the flow in a realistic porous region composed of 6mm Raschig rings. Modelling results were used to determine the probability density function (PDF) distribution of liquid velocity vector orientation angle which was then implemented into 2-fluid Euler-Euler multiphase model of packing column. The simulation showed that the model is capable to simulate adequately the liquid redistribution in a porous region being, however, much more efficient computationally than the VOF method.

Numerical Study of the CO2 Absorber Performance Subjected to the Varying Amine Solvent and Flue Gas Loads

The paper is devoted to the amine-based post-combustion carbon dioxide capture technology. The aim of the paper was to analyze the effect of varying flow conditions on the CO2 capture efficiency of the absorber column. As a research tool, a numerical model of the chemical absorption with aqueous monoethanolamine solution in a packed bed was employed. A complex physio-chemical process including two-phase flow hydrodynamics, heat transfer, and absorption chemistry was simulated by Ansys Fluent commercial software. The parametric study was focused on CO2 capture efficiency in terms of varying loads of amine solvent (liquid) and flue gas. The corresponding changes of liquid holdup, species concentration, temperature and reaction rate distributions are discussed in detail allowing to better understand the absorption column operation. The simulation results have shown clearly the mutual interactions of partial processes and the sensitivity of the system to varying column loads. They have been found to be useful in defining the optimal ranges of operational parameters.

Experimental study of gas-liquid heat transfer in a 2-phase flow in a packed bed

The paper deals with an interfacial heat exchange between gas (air) and liquid (water) flowing countercurrently through a packed bed. The experimental investigation was performed with the use of column of 0.1 m inner diameter and filled in with glass Raschig rings. Loads of working media ranged between 0.018÷0.142 m3(m2s)-1 and 0.0007÷0.0053 m3(m2s)-1 for gas and liquid phases, respectively. It was found that interfacial Nusselt number is mainly dependent on the gas load, noticeably influenced by the temperature difference between phases and practically independent of the liquid load.