Activation of regenerated CoMo/Al2O3 hydrotreating catalysts by organic additives – The particular case of maleic acid

摘要: Abstract Activation of hydrodesulfurization (HDS) catalysts through sulfidation oxide precursors is a critical procedure required to achieve preparation the Co(Ni)-promoted Mo(W)S2 sulfides commonly used for performing sulfur removal from transportation fuels. Better optimized HDS can be reached if organic additives, glycol-type compounds or chelating agents, are during activation process. Moreover, comprehension role additives has become even more essential with increasing necessity regenerate satisfactorily last generation catalysts, sensitive harsh conditions oxidative regeneration treatment. In this respect, maleic acid (MA) was recently found an efficient additive regenerated catalysts. present study, deeper understanding played by restoring activity determined at different steps CoMo-Al2O3 (here called CoMo-R) catalyst. Comparison first performed two other agent, ethylenediaminetetraacetic (EDTA) and compound, triethyleneglycol (TEG), after impregnation drying steps, using UV–vis diffuse reflectance spectroscopy, ex situ in X-ray diffraction thermal analysis. Results emphasized that most extracting cobalt molybdate species leading much better catalytic properties 4,6-dimethyldibenzothiophene (4,6-DMDBT) straight run gasoil. The step also carefully analyzed CoMo-R presence MA inductively coupled plasma atomic emission spectroscopy (ICP-AES), photoelectron, Raman electron paramagnetic resonance spectroscopies, mass spectrometry analysis transmission microscopy. This detailed allows proposing complete description mechanism key aspects