Development of Al-stabilized CaO-nickel hybrid sorbent-catalyst for sorption-enhanced steam methane reforming

In this work, Al-stabilized CaO-Ni hybrid sorbent-catalysts integrated in a single particle with various nickel loadings (12, 18 and 25 wt% NiO) were developed and tested in cyclic hydrogen production by sorptionenhanced steam methane reforming (SESMR) process. A simple wet-mixing technique based on limestone acidification and two-step calcination was employed to produce hybrid materials with different nickel loadings. All developed materials were characterized by BET, XRD, SEM and TEM and studied during 25 CO2 sorption/ regeneration cycles as well as for 10 SESMR cycles. Based on both CO2 sorption and SESMR results, it was concluded that the proposed hybrid sorbent-catalyst with NiO loading of 25 wt% led to the best performances: (i) CaO molar conversion is 41.2% at the end of the 25th sorption cycle and (ii) average CH4 conversion and H-2 production efficiency during 10 SESMR cycles are remarkable (99.1% and 96.1%, respectively). For the most efficient hybrid sorbent-catalyst (25 wt% NiO), the influence of CH4 flow rate and steam to carbon ratio (S/C) was also investigated, as well as its behavior during long-term cyclic operation of SESMR (30 cycles), where the H-2 production time was just limited to pre-breakthrough period. The very efficient performance (average of H-2 yield 97.3%) of the proposed hybrid sorbent-catalyst material in long-term operation confirmed its high potential for use in SESMR process. (c) 2014 Elsevier Ltd. All rights reserved.