Energy storage efficiency analyses of CO₂ reforming of methane in metal foam solar thermochemical reactor

Highlights: • Energy storage efficiency of solar driven CO₂ reforming of CH₄ is analyzed. • FVM with LH kinetics model is developed to analyze process of CO₂ reforming of CH₄. • Effects of key operational parameters on energy storage efficiency are analyzed. • Maximum energy storage efficiency is found when the CH₄/CO₂ ratio is 0.67. - Abstract: Solar driven CO₂ reforming of methane can store extra 20% concentrated solar energy to chemically bonded energy. With the aim to evaluate key operational parameters on energy storage efficiency, a finite volume method (FVM) coupled with thermochemical kinetics was developed to analyze the solar driven CO₂ methane reforming performance in a metallic foam thermochemical reactor. The LH kinetic model of CO₂ reforming of methane was compiled by user defined functions (UDFs) to exactly predict the temperature distribution and mole fractions of gas species. The numerical results were validated with experimental results which were tested in Niigata University to guarantee the accuracy of the developed model. Effects of gas mixture inlet velocity, porosity of metal foam reactor, CH₄/CO₂ ratio and heat flux distribution on energy storage efficiency were analyzed for providing theoretical guideline to the application of solar driven CO₂ methane reforming. The numerical results indicated that maximum energy storage efficiency of CO₂ reforming of methane was found when the CH₄/CO₂ ratio is 0.67.