Anti-coking Effect of MnCr2O4 Spinel Coating during Light Naphtha Thermal Cracking

摘要

The research aimed at fabricating MnCr2O4 spinel coating on HP 40 alloy, and evaluating the influence of the spinel coating on coking behavior during thermal cracking of light naphtha. MnCr2O4 spinel coating formed on the alloy surface by selectively oxidized under low oxygen partial pressure atmosphere at 1050°C for 20 h. The as-formed spinel coating was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results show that the spinel scale is uniform and compact, with blade-like structures on the top. The coking behavior was studied from the morphology and microstructure of coke, and characterized by scanning electron microscope (SEM) and Raman spectra, respectively. The results show that, only globular coke presents on MnCr2O4 spinel coating compared with blank alloy, and the coke exhibits more disordered . graphite structures. Thus, the spinel scale has a favorable anti-coking property.