Kinetic Behavior of Fabricated CuO/ZrO2 Oxygen Carriers for Chemical Looping Oxygen Uncoupling

Chemical looping with oxygen uncoupling (CLOU) is an innovative alternative to conventional combustion. CuO/ZrO2 oxygen carriers were tested in this system for their effectiveness and resilience. Cupric oxide (CuO) was demonstrated to be a reliable oxygen carrier for oxygen-uncoupling with consistent recyclability even after 50 redox cycles in a thermogravimetric analyzer (TGA). The reduction of CuO to generate Cu2O and oxygen was observed to be improved markedly for experiments operated at higher temperatures; however, the oxidation of Cu2O by air to generate CuO was hindered for experiments carried out at elevated temperatures. The reduction rate of fabricated CuO/ZrO2 particles containing 40% CuO was enhanced with increasing temperature and decreased with increasing particle size for experiments operated in a fixed bed reactor. The geometrical contraction and Avrami-Erofe'ev models were demonstrated to be appropriate for describing the reduction and oxidation of CuO/ZrO2, respectively. The activation energies for the reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively, based on experimental results in the temperature range between 850 and 1000 degrees C.

Automated summary

Cupric oxide (CuO) was proven to be a reliable oxygen carrier for chemical looping with oxygen uncoupling (CLOU), showcasing consistent recyclability after 50 redox cycles. The reduction of CuO to generate Cu2O and oxygen was observed to be more efficient at higher temperatures, while the oxidation of Cu2O by air to generate CuO was hindered at elevated temperatures. The reduction rate of CuO/ZrO2 particles increased with temperature and decreased with particle size in a fixed bed reactor, while the activation energies for reduction and oxidation were determined to be 250.6 kJ/mol and 57.6 kJ/mol, respectively.