A directly irradiated solar reactor for kinetic analysis of non-volatile metal oxides reductions

A directly irradiated solar reactor was designed and built to develop kinetic analysis of metal oxides reductions present in many high-temperature thermochemical processes. The reactions were monitored by measuring the oxygen concentration in a carrier gas stream. The pattern flow in the reactor cavity was determined by applying the dispersion law. The dimensionless group D/uL was calculated for flows of 9, 12, and 15Nl/min, and room and operation temperature. It was found to be close to an ideal plug flow behavior in every case. The solar reactor was also thermally characterized, which involved the operation temperature measurement and the thermal efficiency obtaining. For an incoming power of 530W, temperatures higher than 1400 degrees C were measured at the middle of the cavity (where the sample should be placed), and thermal efficiency of 41.6% was calculated. Then, a methodology for kinetic analysis was proposed and applied to a case study. It consisted of a combination of experimental results and a numerical model that reproduced the reactant sample performance. Kinetic was obtained for the layer of reactive particles that were directly heated by concentrated radiation. Kinetic data were fitted to diffusion-controlled mechanism, and obtained kinetic parameters were E-a=362kJ/mol and A=1.39 center dot 10(9)/s. Copyright (c) 2015 John Wiley & Sons, Ltd.