Abstract: The ‘pulverization’ phenomenon occurring in the propane dehydrogenation reactor lining during operation severely restricts the long-term operation of the unit. The pulverized lining was analyzed by characterization techniques such as X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results indicate that iron (Fe) present in the bauxite lining could catalyze the filamentous carbon formed from alkanes, which generates significant expansive stress within the lining, leading to its failure. By studying the weight gain behavior of bauxite under different atmospheres, the promoting effect of hydrogen in the reaction atmosphere on the formation of filamentous carbon was clarified. The weight gain of bauxite under different atmospheres and temperatures was also investigated. The results show that the temperature of filamentous carbon formed is reduced significantly when hydrogen coexists with propane/ propylene, and propylene is more prone to cracking on the iron oxide surface to form filamentous carbon compared to propane. Based on the experimental results, a preliminary safe operating range for bauxite linings has been established, providing a reference for the selection of reactor lining materials and the optimization of process conditions.

Key words: bauxite lining, pulverization, propane dehydrogenation, reactor, ferrum, filamentous carbon, safe operating range