Preparation Oftitanium Nanomaterials For Catalytic Oxidation Desulfurization Of Diesel

In recent years,the acid rain and photochemical smog pollution which were leaded to the SOx from the burning of fuel of sulfur-containing compounds damage the ecological environment.It is a research hot spot to reduce the content of sulfur-containing compounds in oil in petroleum chemical industry.As the standard of sulfur content is more severe in the world,the limitations of the traditional hydrodesulfurization(HDS)is becoming more and more serious.Hence,oxidation desulfurization(ODS)arose gradually in the sights of the researchers because of its mild conditions and high desulfurization efficiency.In this work,titanium nanotubes were prepared by hydrothermal method,and pickled by hydrochloric acid to obtain titanium nanotubes with different lengths.The titanium nanomaterials was evaluated in model fule and diesel as a catalyst for ODS.The results showed that the shorter titanium nanotube has high selectivity on removing 4,6-DMDBT.Titanium nanotubes were characterized by X-ray Diffraction(XRD),Scanning Electron Microscopy(SEM),Transmission Electron Microscopy(TEM),Nitrogen Adsorption-Desorption and Raman Spectroscopy(Raman).And the effect of Titanium Nanotubes Tube Length on catalytic oxidative desulfurization activity of different sulfur compounds in the model fuel has been investigated.The results showed that when the hydrochloric acid pickling concentration increased,the tubular structure of titanium nanotubes was destroyed and the long tube was broken into short tubes.At the same time,it was found that the shorter titanium nanotubes pickled with 0.3 mol/L HCl has an active effect on 4,6-DMDBT(4,6-Dimethyldibenzothiophene)removal.The reason may be that the the shorter titanium nanotube has little resistance,so that the macromolecular sulfur compounds 4,6-DMDBT enters into the interior of the shorter titanium nanotubes,and the interaction of the internal Ti-η1-OOH impel the oxidation of 4,6-DMDBT to 4,6-DMDBTO2.The performance of the shorter titanium nanotubes was evaluated in the reaction of catalytic H2O2 oxidation-extraction desulfurization in model fuel with methanol as the extraction agent.The results showed that the 4,6-DMDBT removal rate can reach 99.7%at the reaction temperature was 45℃,the catalyst dosage was 6.67 g/L,n(H2O2)/n(4,6-DMDBT)=4 and the model fuel and extractant(methanol)were 15 mL.Moreover,the addition of xylene and cyclohexane has no effect on the activity of the shorter titanium nanotubes,it shows an efficient selective oxidation desulfurization performance.There was almost no decrease on catalytic activity after 8 times recycle of the catalyst.Based on the research of the model fuel,the performance of the shorter titanium nanotubes was evaluated in the reaction of catalytic CHP(cumene hydroperoxide)oxidation desulfurization in diesel.The results showed that after the oxidation treatment,almost all of the sulfur compounds in diesel were converted into the corresponding sulfones.After the extraction of sulfone by acetonitrile,the content of sulfur in diesel oil decreased from 9256.9 ppmw to 2427.9 ppmw,the desulfurization rate was 78.3%.The effects of extraction conditions on the desulfation of oxidized diesel were also investigated.At the same time there was almost no decrease on catalytic activity after 10 times recycle of the catalyst.