Experimental investigation of pressure drop in packed beds of irregular shaped wood particles

The knowledge of the pressure drop across a packed bed of irregular shaped wood particles is of greatimportance for achieving optimal control and maximum efficiency in many applications, such as wooddrying, pyrolysis, gasification and combustion. In this work the effect of porosity, average particle size andmain particle orientation on the pressure drop in a packed bed is investigated. To this end, particle sizedistributions and porosities are determined experimentally.Based on the experimental results obtained in this study, the form coefficient C and the permeability K of theForcheimer equation are calculated for different packed beds. The Ergun equation requires an averageequivalent particle diameter that is derived from the measured particle size distribution. This equivalentdiameter and the corresponding bed porosity are used in the well known Ergun equation in order to deriveadapted shape factors A and B.Since a change in bed porosity and particle size, caused by the degradation of the wood particles and gravity,can be expected in a reacting packed bed, a set of shape factors for use with the Ergun equation isdetermined that are independent of porosity and particle diameter and fit the experimental data very well.     «

The knowledge of the pressure drop across a packed bed of irregular shaped wood particles is of greatimportance for achieving optimal control and maximum efficiency in many applications, such as wooddrying, pyrolysis, gasification and combustion. In this work the effect of porosity, average particle size andmain particle orientation on the pressure drop in a packed bed is investigated. To this end, particle sizedistributions and porosities are determined experimentally.Based on the experimental...     »