Ni/CaO.Ca12Al14O33 Based-Materials for Hydrogen Production by CO2 Sorption Enhanced Steam Methane Reforming
Pp. 33-59 (27)
Moises R. Cesario, Braulio S. Barros, Claire Courson and Dulce M.A. Melo
Sorbents with different CaO/Ca12Al14O33 ratios were prepared by microwaveassisted
self-combustion. Catalysts were prepared by Ni wet impregnation of sorbents
and a catalyst with an optimized composition was also prepared by microwave-assisted
self-combustion method. Then, the CO2 sorption capacity and catalytic activity in
sorption enhanced steam methane reforming (SE-SMR) for production of hydrogen
were evaluated. X-ray diffraction (XRD) analysis of reduced catalysts confirmed Ni,
CaO and Ca12Al14O33 phases. Catalysts prepared by wet impregnation favor high surface
area, and consequently the CO2 sorption. The CO2 sorption by CaO modifies the
equilibrium of the water gas shift reaction (WGS) and consequently the hydrogen
production is improved at 650 ºC. The time of breakthrough for H2, CO, CO2, and CH4
depends on both the excess of CaO and operating conditions (H2O/CH4 ratio). Ni-CA75
catalyst obtained by impregnation method with a CaO excess around 75% leads to the
optimum activity. It exhibits high sorption capacity and hydrogen selectivity of 100%
during 2 h and 16 h for H2O/CH4 ratios of 3 and 1, respectively. Therefore, Ni-CA75 is
the most active and stable catalyst during 50 h in CO2 sorption enhanced steam
methane reforming, even at an unusually low temperature (650 ºC).
CO2 Sorbent, Hydrogen, Microwave-Assisted Self-Combustion, Ni
Catalyst, Sorption Capacity, Steam Methane Reforming, Wet Impregnation,
Water Gas Shift.
Unite de Chimie Environnementale et Interactions sur le Vivant (UCEIV, E.A. 4492), MREI, Universite du Littora.