Hydrogen production via sorption enhanced steam reforming of butanol: Thermodynamic analysis

Thermodynamic equilibrium for sorption enhanced steam reforming of butanol (SESRB) to hydrogen was investigated using Gibbs free energy minimization method. The optimal operation conditions for SESRB are at 800 K, the steam-to-butanol molar ratio of 10, the calcium oxide-to-butanol molar ratio of 8 and atmospheric pressure. Under the optimal conditions, complete conversion of butanol, 97.07% concentration of H2 and 0.05% concentration of CO2, and efficiency of 86.60% could be achieved and at which no coke tends to form. Under the same conditions in SRB, 58.18% concentration of H2, 21.62% concentration of CO2, and energy efficiency of 81.51% could be achieved. Butanol steam reforming with CO2 adsorption has the higher H2 content and efficiency, and lower CO2 content than that without adsorption under the same reaction conditions. In addition, reaction conditions for coke-free and coke-formed regions are also discussed in butanol steam reforming with or without CO2 separation.

Research highlights
► In our study we firstly investigate the thermodynamic properties of sorption enhanced steam reforming of butanol (SESRB).
► The influences of reaction temperature, pressure, steam-to-C4H10O molar ratio and CaO-to-C4H10O molar ratio on reaction systems were analyzed to determine optimal conditions to produce H2 for PEMFC.
► Coke-formed and coke-free regions were also discussed for SESRB.