关键词: 焦炉煤气, FeMo/Al₂O₃催化剂, 加氢脱硫, 催化剂积炭, 失活机理

Abstract:

Taking the pre-hydrogenation conversion fresh catalyst and deactivated catalyst used in the deep purification process of coke oven gas as the research object, we used a micro-fixed-bed reaction device to carry out the hydrodesulfurization (HDS) activity evaluation. The carbon deposition and deactivation mechanisms of pre-hydrogenation reforming catalyst were explored by characterizations using N₂-sorption desorption apparatus, X-ray diffraction (XRD), Raman spectroscopy, thermo-gravimetric analysis (TG-DTG), scanning electron microscope with energy dispersive spectrometer (SEM-EDS), UV-Vis spectroscopy and high-frequency infrared carbon-sulfur analyzer. The research result showed that the carbon deposition covering the active sites on the catalyst surface and the catalyst pore blocking were the main deactivation reasons. Meanwhile, the loss of active components (Fe and Mo) during the process of carbon deposition and the catalyst sintering during regeneration process also contributed to the deactivation of the catalysts. Secondly, the form of carbon deposition is dominated by spherical graphitic carbon, increasing gradually from the inside of the catalyst to outside. Finally, except for the catalysts of anisotropic strips and pentagonal spheres, other deactivated catalysts can be reused after regeneration (600 °C, air atmosphere). However, the hydrotreating activity of the catalysts decreased after regeneration, mainly due to the reduction of the catalysts' surface, pore volume and the loss of active components.

Key words: coke oven gas, FeMo/Al₂O₃ catalyst, hydrodesulfurization, catalyst coking, deactivation mechanism