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This paper presents the results of thermophysical characterization of the powder resulting from the solar drying of Moringa oleifera leaves. The desorption isotherms of the powder, are determined by the gravimetric static method. The models of B.E.T, Smith, Henderson, Iglesias and GAB are used for the smoothing of the experimental points. The Clausius-Clayperon and GibbsHelmholtz equation are used for the determination of thermodynamic properties. The isotherms obtained are with type II. The theoretical curves of GAB present a better similarity with the experimental curve at 55°C. The monolayer moisture content (Xm) is 6.32 and 7. 24 % at 30° C; 5.13 and 6.3% at 35 °C; 5.1 and 5.9 % at 45 °C; 4.22 and 4.66 % at 55 °C respectively for BET and GAB models. Isosteric and entropic heats are more important for low values of moisture content. The activation energy of desorption of the powder in the range of temperatures tested is -10.1009539 kJ/mol. Isokinetic temperature (Tβ) and the mean harmonic temperature (Thm) are respectively 301.2435K and 300.12342K and the free energy (ΔGβ) is 302.18 J/mol. The desorption process of the Powder is non-spontaneous and is done by controlled mechanisms enthalpic.

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A two‐step solar thermochemical looping reforming (STCLR) of CH4—Fe3O4 redox cycles via H2O and CO2 splitting is investigated for H2 and CO production. The P1 approximation is adopted for the radiation heat transfer and high‐temperature thermal characteristics of active materials in the reaction medium. A benchmark experimental setup for the conversion of solar energy to syngas based on the solar thermochemical technology is presented. The effects of operating conditions on the yield of H2 and CO as well as syngas production are investigated at both thermal reduction and oxidation steps. It is found that the key performance of two‐step CH4—Fe3O4 redox cycles for a higher H2 and CO production depends on the efficiency of methane and oxidizer (H2O and CO2) conversion. Furthermore, a substantial amount of H2 and CO production with carbon deposition is obtained when the thermal reduction is extended to the mixed oxide solid solution (FeO—Fe). Among the oxygen carriers, FeO exhibits a higher oxygen exchange for H2 production. However, the synergetic effect of FeO—Fe reactivity strongly contributes to syngas yield. The present solar reactor model can significantly contribute to the reduction of greenhouse gas emission by utilizing 40% of CO2 emissions into solar fuels such as H2 and syngas. The results indicate that highly selective syngas with an H2/CO ratio close to 2 can be obtained with a strong control of γ = H2O/CO2.

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