Operational Window of Sorption Enhanced Steam Reforming of Methane over CaO−Ca12Al14O33

This study investigates the operational window of methane reforming in the presence of CO2 sorbent CaO−Ca12Al14O33 (85:15 wt). Atmospheric experiments were conducted, at constant steam to methane ratio and catalyst mass under various sorbent masses, total feed flows, and temperatures. When CaO−Ca12Al14O33 is utilized at 650 °C, the equilibrium is shifted, for all the sorbent masses and the total flow rates studied, to higher hydrogen concentration (>93%) compared to conventional steam reforming (>77%). The methane conversion attained, at 650 °C, is 95%. A mathematical model was developed to describe the kinetics of the CaO−Ca12Al14O33 carbonation. The predicted decrease in the carbonation rate due to the lowering in temperature (650 to 550 °C) agrees reasonably well with the observed 24% loss of methane conversion for the same temperature shift.