Carburization behaviour of Mn–Cr–O spinel in high temperature hydrocarbon cracking environment

This investigation was initiated to understand chemical stability of MnCr2O4 spinel in high temperature carbonaceous reducing environments. MnCr2O4 and Cr2O3 were comparatively tested at 1050 °C for various time periods up to 100 h. It was found that the resistance to carburization of MnCr2O4 is better than Cr2O3, and the carbide conversion rate of MnCr2O4 was slower than Cr2O3. The more porous structure of Cr2O3 than MnCr2O4 after carburization was observed. MnCr2O4 spinel was proved to be more stable than Cr2O3 in carburizing environments according to the results of thermodynamic calculation. After further carburization, coke formation was built up in MnCr2O4 due to the catalytic effect of Mn7C3 converted from MnO.