Sorption properties of lithium carbonate doped CaO and its performance in sorption enhanced methane reforming

In-house prepared lithium carbonate doped CaO was tested for its CO2 sorption properties and suitability as a CO2 sorbent for sorption-enhanced reforming of methane. The new material demonstrated CO2 capacity at the temperatures above the equilibrium for CaO recarbonation reaction. However, the capacity was unstable and decreased during carbonation–regeneration cycles. After sufficiently large number of cycles Li dopant escaped from the sorbent and its sorption behavior resembled to that of CaO. The main route of escape is, probably, a crossover of liquid Li2CO3 onto crucible in TG experiments and onto catalyst in SER tests. Sorption enhanced methane reforming at 2 bar pressure, 750 °C and H2O to CH4 ratio of 4 using novel sorbent yielded as high as 99.8 vol% pure hydrogen during the first cycle. In subsequent cycles the hydrogen purity drastically decreased as a result of severe catalyst poisoning by Li.