An alternative process for nitric oxide and hydrogen production using metal oxides

A new process employing metal oxide is proposed for the production of nitric oxide and hydrogen which are precursors to the production of nitric acid. There have only been a few studies reporting the oxidation of ammonia by metal oxides, but the ammonia-metal oxide reactions for the simultaneous production of NO and H-2 have not yet been reported. The reaction of ammonia with different metal oxides is investigated in detail, including thermodynamic feasibility calculations. The salient feature of the proposed reaction is the production of H-2 in addition to NO. Experiments are performed for the most feasible metal oxides in a semi batch reactor. These experiments confirm the feasibility of the ammonia-metal oxide reaction for cupric oxide (CuO), ferric oxide (Fe2O3) and cobalt oxide (Co3O4) at 825 degrees C, 830 degrees C and 530 degrees C, respectively. The maximum yields of NO are around 90% for each metal oxide. The effect of varying the different parameters such as temperature, ammonia concentration, and particle size on the yield of nitric oxide is reported for the case of CuO and a reaction mechanism is proposed to explain these results. These results are used to develop two different chemical looping based processes for NO and H-2 production depending on the mode of regeneration of metal oxides. Crown Copyright (C) 2016 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. All rights reserved