Experimental and computational investigations of ethane and ethylene kinetics with copper oxide particles for Chemical Looping Combustion

This study was aimed at determining the important reaction steps involved in the oxidation of methane, ethane, and ethylene with CuO particles at different temperatures. The reaction pathways for the oxidation of methane, ethane, and ethylene with CuO were obtained by reactive force field (ReaxFF) molecular dynamics simulations between temperatures of 1000 K and 2000 K. Experiments in a fixed-bed flow reactor were conducted with methane, ethane, and ethylene at 500-1000 K with time-dependent species measurements from an electron-ionization molecular beam mass spectrometer (MBMS), and species validation with GC for detection of complete and intermediate combustion products. MBMS and GC allowed for the detection of oxygenated species and larger species produced from radical reformation. The simulation and experiment agreed on the production of such species as CH₃CHO, CH₂O, CO, and H₂O, which allowed for the creation of simple C1 and C2 reaction pathways, which can be used in kinetic models of C2 species and larger fuels such as biofuels. The simulation and experiment disagreed on the formation of C₂H₂, CH₃OH, and CO₂, with large amounts of C₂H₂ being measured in the ethylene oxidation simulations and CH₃OH being formed in methane oxidation simulations, while neither species was experimentally found. Large amounts of CO₂ were rapidly produced in experiments with C2 fuels at 800 K, while little-to-no CO₂ was observed in simulations. This was possibly due to the extremely short timescale of the simulations, preventing total oxidation of the fuel. The differences in products produced between simulation and experiment allowed for the potential to modify the ReaxFF potential functions to more accurately model the experimental products of Cu-H-O-C reaction kinetics.