Qualitative and quantitative insights into multiphase flow in ceramic sponges using X-ray computed tomography

• X-ray computed tomography of multi-phase flow in ceramic sponges.
• Data processing routine for tomographic images.
• Phenomenological study about hydrodynamics in solid sponges.
• Local hold-up distribution inside a sponge packing.
• Effective gas-liquid interfacial area distribution.

Hydrodynamic parameters of ceramic sponges as column internals are investigated using X-ray computed tomography. New qualitative and quantitative insights into multiphase flow in ceramic sponges are gained and a phenomenological study is performed to investigate the flow paths, the hold-up and the effective gas–liquid interfacial area of the trickling liquid inside the sponge packing. The formation of rivulets inside the sponge packing and a redistribution of the liquid at intersections are detected. Additionally, it was observed that the liquid paths inside the sponge start to fluctuate with a higher superficial liquid velocity. A specially designed data processing routine is developed. In the experiments, the test column is operated in co-current (downwards) as well as countercurrent mode with an air–water system. The results are compared to literature data to evaluate the accuracy. The sponges investigated are varied in material, porosity and cell density to obtain knowledge concerning dependencies. The cell density and the superficial liquid velocity turned out to be the significant parameters for the hold-up and the effective gas–liquid interfacial area.