Catalytic performance of Ni/CaO-Ca5Al6O14 bifunctional catalyst extrudate in sorption-enhanced steam methane reforming

• Ni/CaO-Ca5Al6O14 exhibited high activity and stability in 50 cycles of CO2 capture.
• Ni/CaO-Ca5Al6O14 extrudates had high activity and stability over 10 SESMR cycles.
• Ca5Al6O14 acted as a support matrix to stabilize the bifunctional catalyst.
• Advantages of Ni/CaO-Ca5Al6O14 over the catalyst/sorbent mixture were demonstrated.
• A screened catalyst had good stability over 20 cycles at a low H2O/CH4 ratio of 2.

In this work, mm-sized shaped Ni/CaO-Ca5Al6O14 bifunctional catalyst extrudates were prepared by extruding sol–gel-derived Ni/CaO-Ca5Al6O14 powder, and applied to the sorption-enhanced steam methane reforming (SESMR) process. The Ca5Al6O14-stabilized bifunctional catalysts exhibited higher stability and CaO utilization efficiency than that of Ni/CaO when subjected to 50 carbonation–calcination cycles for CO2 capture, indicating the positive effect of Ca5Al6O14 incorporation. The Ni/CaO-Ca5Al6O14 extrudates possessed good activity and stability over 10 SESMR cycles, and showed advantages over the use of catalyst and sorbent mixture, including an extended prebreakthrough time and a higher catalytic activity. In particular, the Ni/CaO-Ca5Al6O14 extrudate consisting of 15 wt% (mass fraction) Ni, 61.7 wt% CaO and 23.3 wt% Ca5Al6O14 provided high activity and stability for the SESMR process, even at a low H2O/CH4 molar ratio of 2 over 20 SESMR cycles. These results clearly demonstrate that the Ni/CaO-Ca5Al6O14 extrudate is an interesting candidate for the SESMR process.

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