Thermodynamic and Process Analyses of Syngas Production Using Chemical Looping Reforming Assisted by Flexible Dicalcium Ferrite-Based Oxygen Carrier Regeneration

Syngas production is highly critical to the manufacturing of many value-added products, and its economic prospects can be increased through the enhancement of fuel conversion and the syngas yield. This study explores the thermodynamic characteristics of syngas production through chemical looping reforming (CLR) of natural gas using dicalcium ferrite (Ca2Fe2O5) as the oxygen carrier in a cocurrent moving-bed reactor. The effects of temperature, pressure, and steam addition are studied for both isothermal and adiabatic conditions. A natural gas conversion of 99.78% and a yield of 2.86 mol of syngas/mol of natural gas are obtained for CLR as compared to 95.97% and 2.70, respectively, for autothermal reforming (ATR). A fluidized bed and a countercurrent moving bed are employed for the regeneration of reduced solids using air and a steam/CO2 mixture, respectively, thereby achieving operational flexibility. The syngas yield increases by similar to 41% using the steam/CO2 mixture, whereas a high-purity H(2 )is obtained from the oxidation of reduced solids in pure steam. The process analyses indicate an increase in the effective thermal efficiency from 86.4% to 92.2% and the exergy efficiency from 79.5% to 85.3% on using the Ca2Fe2O5-based CLR over ATR, rendering the syngas production using CLR economically attractive.