Can Steam- and CO-Rich Streams Be Produced Sequentially in the Isothermal Chemical Looping Super-Dry Reforming Scheme?

Super-dry reforming of methane (CH + 3CO → 2HO + 4CO) is a very promising route for CO utilization. To maximize the yield of CO, a water-gas shift reaction (CO + HO → CO + H) should be circumvented. Combination of dry reforming of methane, redox reactions (metal oxide is reduced by CO and H in one step and then oxidized by CO in the next step), and CO sorption in a fixed-bed reactor was proposed as a potential approach to suppress the water-gas shift reaction. It was demonstrated that this isothermal operation can produce two separate streams, one is rich in steam and the other in CO, in a redox cycle at 750 °C. However, both the thermodynamic analysis and experimental investigations suggest that steam- and CO-rich streams may not be produced sequentially in the redox mode at 750 °C.