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Improved Sorption‐Enhanced Steam Methane Reforming via Calcium Oxide–Based Sorbents with Targeted Morphology
Author(s) -
Alshafei Faisal H.,
Minardi Luke T.,
Rosales Derrick,
Chen Gen,
Simonetti Dante A.
Publication year - 2019
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201800807
Subject(s) - nanofiber , electrospinning , chemical engineering , materials science , crystallite , sorbent , sorption , calcium oxide , steam reforming , nuclear chemistry , chemistry , nanotechnology , catalysis , hydrogen production , adsorption , composite material , organic chemistry , metallurgy , engineering , polymer
Calcium oxide (CaO)‐based sorbents for sorption enhanced steam methane reforming (SE‐SMR) that achieve stoichiometric capacity are synthesized via thermal and electrospinning methods. Small CaO crystallites (39 nm) and macroporous intrafiber networks imparted by electrospinning lead to stoichiometric capacities (0.79 g CO 2 g sorbent− 1) and uptake kinetics (first order rate constant, k = 8.9 × 10 −4 ± 1.8 × 10 −5 cm 4 mol −1 s −1 ) at 873 K that are superior to CaO derived from thermal syntheses (0.05 − 0.7 g CO 2 g sorbent− 1and k < 5.0 × 10 −4 ± 2.5 × 10 −6 cm 4 mol −1 s −1 ). Al‐doped electrospun CaO samples (Al:Ca ratios of 3:10, 1:10 and 2:10) also exhibit high sorption capacities (0.35 − 0.74 g CO 2 g sorbent− 1at 873 K) and are stable over multiple reaction‐regeneration cycles (<5% loss in initial capacity after 15+ cycles). X‐ray diffraction and scanning electron microscopy analysis reveal that thermally stable Al‐Ca mixed phases (Ca 12 Al 14 O 33 ) mitigate crystallite agglomeration and maintain macroporous structures imparted by electrospinning. Nanofibers and Al‐doped nanofibers (Al:Ca ═ 2:10) exhibit more than a factor of three longer CO 2 breakthrough time compared to CaO from marble (1650, 6400, and 7500 mL g sorbent −1 for CaO‐marble, 2Al‐10Ca‐O‐nanofibers, and CaO‐nanofibers respectively) under reforming conditions, with Al‐doped CaO‐nanofibers retaining 94% of their initial performance after ten reforming‐regeneration cycles, indicating their potential as improved sorbents for SE‐SMR processes.