(654f) A DFT Study of so2 Binding on CuMn2O4 Oxygen Carrier for Chemical Looping with Oxygen Uncoupling | AIChE

(654f) A DFT Study of so2 Binding on CuMn2O4 Oxygen Carrier for Chemical Looping with Oxygen Uncoupling


Talebi, M. - Presenter, University of California, Irvine
Barua, T., University of California, Irvine
Padak, B., University of California, Irvine
Chemical looping with oxygen uncoupling (CLOU) is a variant of chemical looping combustion (CLC), which is one of the promising carbon capture and storage technologies. In CLOU, the fuel reacts with gaseous O2 released by a metal oxide, called the oxygen carrier, at suitable temperatures and oxygen partial pressures, unlike the CLC, where only the lattice oxygen reacts with the fuel. The kinetically favored gas-solid reaction makes CLOU more effective than CLC for solid fuels like coal and biomass. As a CLOU oxygen carrier, bi-metallic Cu-Mn has demonstrated high fuel combustion efficiency for both solid and gaseous fuels. However, sulfur compounds of the fuel might poison the oxygen carrier by reacting with the metal oxide; thus, reducing its reactivity. Authors have recently conducted an experimental study on the effects of SO2 on this oxide’s performance. However, first principle based theoretical studies to examine the interaction of SO2 on this oxygen carrier surface is scarce in literature.

Therefore, the purpose of this study is to investigate SO2 binding on the CuMn2O4 (100) surface employing density functional theory (DFT) and ab initio thermodynamics. SO2 binding was studied at various possible sites with different SO2 molecular orientations. All DFT calculations were performed using the Vienna Ab Initio Simulation Package (VASP). The optimized configurations obtained from the calculations were examined to identify active binding sites and stable adsorption geometries of SO2. Finally, ab initio thermodynamic calculations were performed to relate the DFT-obtained results to experimental reaction conditions. It was found that SO2 binding on the surface is energetically favorable. Furthermore, the thermodynamic calculations show that the SO2-bound CuMn2O4(100) surface is thermodynamically stable at the CLOU operating conditions, which is consistent with the authors’ previous experimental observations.