Thermodynamic Investigation of Process Enhancement in Chemical Looping Reforming of Methane through Modified Ca–Fe Oxygen Carrier Utilization

Abstract

Production of various value-added chemicals through natural gas conversion with syngas as an intermediate is becoming increasingly popular because of the abundance of natural gas and maturation of syngas-producing technologies. Chemical looping reforming is one such technology that is envisioned as a substitute to the existing syngas production processes such as steam methane reforming, autothermal reforming, and partial oxidation of natural gas (POX) because of its superior thermodynamic capabilities and less parasitic energy requirements. The proposed work makes use of CuO-modified Ca2Fe2O5-based oxygen carriers for syngas production through chemical looping, where the system performance is subjected to thermodynamic scrutiny. The main objective of the proposed work is to assess the change in syngas production capability and other process parameters because of reduced endothermicity of the process through CuO incorporation. Thermodynamic simulations are carried out to assess the system performance at various operating temperatures, pressures, and lattice oxygen availability. Parameters such as the effective thermal efficiency, cold gas efficiency, and exergy efficiency are calculated to evaluate the performance of oxygen carriers with varying compositions of CuO. These parameters are measured for two process configurations: isothermal and thermoneutral. An overall process simulation is further carried out to gain a deeper perspective of the changes occurring in the chemical-looping system because of CuO modification of the oxygen carrier.