Performance of a combined CaO-based sorbent and catalyst on H2 production, via sorption enhanced methane steam reforming

• A hybrid CO2 sorbent and reforming catalyst was synthesized through physical mixing.
• It presents a CO2 carrying capacity over 20 wt.% with respect the CaO in the solid.
• H2 percentages close to equilibrium are achieved even for a steam to carbon ratio as low as 1.5.
• It was tested cyclically under realistic conditions with H2 yields over 90 vol.%

The performance of an hybrid material CO2-sorbent and reforming catalyst under Sorption Enhanced Reforming of methane has been assessed. The material was synthesised through physical mixing of CaO, NiO and calcium cement aluminate (varying the proportion CaO/NiO to produce three different solids). The materials, that presented a stable CO2 carrying capacity of 20 wt.% of the total CaO in the solid, were able to reach gas product composition very close to thermodynamical equilibrium (at 650 °C, steam to carbon ratio, S/C, of 3 and 1200 h−1 CH4 spatial velocity), with H2 composition over 94 vol.% (dry basis). In addition, it has also been demonstrated that the hybrid materials with NiO wt.% contents of 14 and 18.5 can fulfill the thermodinamical equilibrium at S/C ratios as low as 1.5. Finally the 18.5% NiO material has been tested in cyclic operation, under realistic conditions by regenerating the sorbent in oxidizing conditions. The cycled material showed slight increase of NiO crystal size that resulted in slight loose of activity after cycling. However, H2 percentages over 90 vol.% (dry basis) were always obtained.