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Thermodynamic analysis of Mg x Fe 3‐x O 4 redox CO 2 conversion solar thermochemical cycle
Author(s) -
Bhosale Rahul R.,
Rashid Suliman
Publication year - 2022
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.7213
Subject(s) - thermochemical cycle , inert gas , redox , chemistry , thermodynamics , analytical chemistry (journal) , inert , energy conversion efficiency , thermal , heat recovery ventilation , inorganic chemistry , heat exchanger , catalysis , chromatography , organic chemistry , hydrogen production , physics
Summary The solar‐to‐fuel energy conversion efficiency (η solar − to − fuel ) of the Mg x Fe 3‐x O 4 (x = 0.2‐1.0) based CO 2 splitting (CDS) cycle is estimated at steady reduction ( T red ) and oxidation temperatures ( T oxd ) equal to 1673 K and 1273 K, respectively. The efficiency analysis is performed using the experimental results reported in the sol‐gel‐derived Mg x Fe 3‐x O 4 based CDS cycle. The redox nonstoichiometry allied with the Mg x Fe 3‐x O 4 during the reduction ( δ red ) and oxidation steps ( δ oxd ) is determined based on the experimentally obtained results. Efficiency analysis is conducted by considering the heat energy required to heat inert sweep gas and CO 2 . Heat penalty allied with the separation of the inert sweep gas from O 2 and CO 2 from CO is also considered. The solid‐to‐solid heat recovery effectiveness ( ε ss ) is assumed to be zero, whereas the gas‐to‐gas heat recovery effectiveness ( ε gg ) kept steady at 0.5. The release of a high amount of O 2 and the production of an elevated CO level is responsible for the rise in the energy penalty associated with both separators. The obtained results also indicate that the total thermal energy required ( Q ̇ MgF − TC ) to drive the cycle depends heavily on the sensible heat required ( Q ̇ MgF − sens ) for raising the temperature of Mg x Fe 3‐x O 4 from T oxd to T red . The obtained results also show thatη solar − to − fueldepends heavily on the amount of CO produced and hence recorded to be the highest (4.3%) in the case of MgFe 2 O 4 .