Powder entrapment in a multi-phase flow packed bed

Multiphase-phase flow in packed beds can be found in many industrial applications, for example, granular filters for (hot) gas cleaning and the flow of unburnt coal in an ironmaking blast furnace. Understanding the mechanisms governing powder entrapment in packed beds and relevant issues such as powder holdup and bed permeability is an important step towards the modelling of such a flow system. This paper presents a study of powder entrapment and its effect on gas pressure drop in a gas-powder two-phase flow bed with and without liquid holdup. It is found that the contact point between particles plays an important role in the capture of powder and the presence of a liquid phase in the packing may significantly increase the powder holdup and gas pressure drop. The effects of variables relevant to blast furnace conditions, such as gas flowrate, powder flowrate, liquid properties, and powder-particle size ratio on the entrapment behaviour are experimentally examined.