Analysis of H_2 and CO production via solar thermochemical reacting system of NiFe_2O_4 redox cycles combined with CH_4 partial oxidation

摘要

Thermal reduction of the partial oxidation of CH4-NiFe2O4 followed by oxidation with H2O and CO2 was numerically investigated for H-2 and CO production. P1 radiation model was used to account for radiative heat transfer. The synergistic effect of the reactivity of Fe/Ni exhibited a very promising strategy for producing 45% of syngas with 2.54 ratios of H-2:CO at the first step and 55% of syngas with 2.34 ratios of H-2:CO at the second step. The increase in incident radiation heat flux to 437.69 kW/m(2) resulted in higher reduction kinetics of species conversion until the formation of oxygen carriers consisting of 65% of FeO, 35% of Ni-Fe and 2.6% of carbon deposition. However, during the reduction process, the decrease in total pressure to 0.05 MPa enhanced the species reactivity and the production of H-2 and CO while minimizing carbon deposition. Moreover, the oxidation temperature, operating pressure and the concentration of oxidizing species have strong impacts on the oxidation kinetics. Unlike high thermal reduction process, increasing the total pressure to 1 MPa has favorable effects on syngas production at oxidation step. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.