| Hydrodesulfurization method is widely used in fuel producing processes. Withmild reaction conditions, high desulfurization efficiency and effective removal ofthiophene and its derivatives which are stubborn for hydrodesulfurization, oxidativedesulfurization has received widespread attention. In the thesis, mesoporoussilica-supported phosphomolybdic acid catalysts were synthesized with sol-gel method.Influences of carboxymethyl cellulose (CMC) or polyethylene glycol (PEG) onstructure and catalytic oxidative desulfurization performance of catalysts wereinvestigated. The main conclusions are as follows:1. Structures of catalysts synthesized with/without pore formers were characterizedby Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD),field emission scanning electron microscopy (SEM) and specific surface and porestructure analysis. Results showed that the Keggin structure of phosphomolybdic acid incatalysts was not destroyed after the addition of CMC and PEG, but promoted thedispersion of active center on silica, the specific surface area of catalysts also increased,which can help improve the catalytic activity of catalysts.2. Preparation conditions and influence factors of oxidative desulfurization wereinvestigated, from which best conditions has been concluded. With10mL model oilwhich sulfur level is400μg/g, dibenzothiophene (DBT) can be almost totally removedwith0.05g catalyst,0.03mL H2O2,15minutes under60℃, benzothiophene (BT) canbe almost totally removed with0.07g catalyst,0.04mL H2O2,20minutes under70℃.Used after5times, catalysts maintained high catalytic activity.3. Kinetic analysis showed that DBT and BT oxidation reaction accords with theapparent first-order kinetic law. The catalytic activation energies of DBT and BT are31.45kJ/mol and43.98kJ/mol, which illustrated that DBT is easier to be oxidized thanBT. Catalysts exhibit better performance with PEG pore former than that of CMC. |
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