Process design for sorption-enhanced chemical looping steam methane reforming: Selection of process configuration and combustible gas type

Process efficiency of sorption-enhanced chemical looping steam methane reforming for H₂ production were developed. The effects of reactor arrangement, namely reforming-oxidation-calcination (R-O-C) and reforming-calcination-oxidation (R-C-O) systems, and combustible gas type (CH₄ vs. H₂) were analyzed through process simulation. The results showed that the R-O-C exhibited higher H₂ production and process efficiency than the R-C-O, regardless of combustible gas type. However, the R-O-C produced CO₂ during the oxidation step due to heat release from the oxidation reaction. Using CH₄ as a combustible gas resulted in greater process efficiency than H₂ but led to increased CO₂ emissions, requiring additional CO₂ capture units. Among all cases studied, the R-O-C using CH₄ as a combustible gas achieved H₂ purity of 87% and process efficiency of 75% at a steam-to-carbon ratio (S/C) of 3, a calcium oxide-to-carbon ratio (CaO/C) of 1, and a nickel oxide-to-carbon ratio (NiO/C) of 0.5 at 600 °C and 1 bar.