A novel two-step fixed bed reactor for the reduction of cobalt oxide under microwave heating

Highlights: • Microwave heating has better performance compared to common furnaces. • High conversion percentage is obtained by using the high-hydrogen syngas. • The designed reactor has appropriate performance in the process of pyrolysis and reduction. • The best conversion was determined to be about 92% at 900 °C and for 4 min. • Enough injected glycerol amount reduces the reaction timing. In this work, a novel two-step fixed bed reactor is designed and constructed for the synthesis of cobalt performed by the reduction of cobalt oxide under microwave heating. In the first step, glycerol is sprayed using a spray device on a bed of activated carbon placed in the bottom of reactor to perform the pyrolysis reaction of glycerol. In the second step, the syngas produced from the pyrolysis reaction is immediately used for performing the reduction reaction of cobalt oxide granules embedded in the bed of activated carbon. The raw material and the obtained products are characterized by FESEM, EDS, and XRD analysis. The effect of temperature and the amount of sprayed glycerol on morphology and conversion rate of products are investigated. The analysis of XRD and EDS proved the formation of 91.75% Co using 7 cc of glycerol at the initial temperature of 900 °C after 4 min.