Performance evaluation of chemical looping air separation/oxygen production at high temperatures

With the Aspen Plus software, simulations and evaluations of chemical looping air separation (CLAS) process were performed. Based on chemical reaction equilibrium principle, equilibrium partial pressures of oxygen under different conditions for the redox of CoO-Co3O4 and Mn3O4-Mn2O3 were calculated. The relations between equilibrium partial pressures of oxygen and operation temperatures were obtained. According to the equilibrium partial pressures of oxygen, the required air flow and steam/CO2 flow for the production of oxygen were determined. Finally, energy consumptions of oxygen production were calculated. The results show that compared with CoO-Co3O4, Mn3O4-Mn2O3 oxide system it is more effective. The energy consumption of CLAS by steam is about 0.353 kW·h/kg of oxygen produced while in conventional cryogenic air-separation system it is about 0.246 kW·h/kg. The energy consumption of CLAS by CO2 is about 0.151 kW·h/kg (φ(O2)=14.3%). Therefore the performance of CLAS by CO2 takes advantages of energy-saving.