Investigation of a Fixed-Bed Reactor for the Calcination of CaCO3 by the Simultaneous Reduction of CuO with a Fuel Gas

Abstract

The exothermic reduction of CuO to Cu using a fuel gas as a source of heat to carry out the simultaneous calcination of CaCO3 in a fixed bed has been evaluated. A dynamic pseudohomogeneous model has been developed to describe in detail the transient behavior of this operation. The experimental tests have been performed in a lab scale packed-bed reactor (i.d. × L = 38 mm × 920 mm) containing a mixture of CaO- and CuO-based particles (with 12 and 60 wt % of active phase, respectively). Preliminary heat-transfer studies have been carried out using inert gases at different temperatures to estimate the overall heat transfer coefficient of the system. An overall heat transfer coefficient of around 5 W/m2 K has been obtained, which is a sufficiently low value to claim an operation close to adiabatic conditions. Hydrogen has been chosen as reducing gas. A Cu/Ca molar ratio of 1.8 in the bed allows both the reduction and calcination fronts to advance together, with moderate maximum temperatures of around 870 °C, l...