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

Abstract

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 sorption-enhanced 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 CO 2 sorption/regeneration cycles as well as for 10 SESMR cycles. Based on both CO 2 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 CH 4 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 CH 4 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. • Al–stabilized CaO–nickel hybrid sorbent–catalyst prepared by limestone acidification. • The hybrid sorbent–catalyst with 25 wt% NiO provided the best results. • CH 4 conversion of 99.1% in cyclic SESMR operation (10 cycles). • H 2 production efficiency of 96.1% (10 cycles) and 97.3% (30 cycles).