COMPUTED RESULTS FOR THE REDUCTION OF IRON OXIDE PELLETS IN MOVING BEDS WITH NON-UNIFORM GAS AND SOLIDS FLOW.

Abstract

A comprehensive set of computed results is presented, describing the reduction of iron oxides with hydrogen in a counterflow packed bed arrangement, when both the gas and solid streams may be maldistributed for both isothermal and non-isothermal conditions. This maldistribution is generated by assigning a radial dependence to both the void fraction and the particle diameter. It was possible to examine cases where preferential flow of the gas occurred in the wall region, while preferential mass flow of the solids took place in the central core and vice versa. It was found that flow maldistribution may have a dramatic effect on the performance of the packed bed reactor by causing a marked distortion of the concentration isopleths When the solid and gaseous streams are mismatched, local reactant starvation may occur, which does not allow the reactions to attain completion, notwithstanding the fact that the overall stoichiometric requirements are met by the system.