| At present, the quality of oil has been required to upgrade by the deterioration of domestic atmosphere and the fast increases in the demand for clean vehicle fuels. Desulfurization technology of gasoline could be divided into hydrodesulfurization and non-hydrodesulfurization. Usually the technology of hydrodesulfurization is under high temperature and high pressure to removal of thiophene with high hydrogen consumption and high investment cost. While the adsorptive desulfurization technology in non-hydrodesulfurization is the most promising technology in desulfurization for the operating conditions are mild and it has advantages of low investment and few octane number loss.On the basis of previous studies on attapulgite desulfurization, the key problems to solve with non-hydrodesulfurization technology in this research are:further studying influencing of oil desulfurization from alkali metals and alkaline earth metals modification attapulgite clay; screening the effective ingredient by evaluation of the modified attapulgite desulfurizer in MTBE, further characterization of the optimal desulfurizer and discussion of the removal mechanism; the desulfurization efficiency with desulfurizer modified by transition metals and alkali metals in gasoline of RFCC of Lanzhou Petrochemical Company. The conclusions are as follows:(1) The desulfurization of attapulgite desulfurizer modified by alkaline earth metals is better than alkali metals, in accordance with the descending order of magnesium nitrate, calcium nitrate, barium nitrate, lithium nitrate, sodium nitrate, potassium nitrate, while the order of their ion-exchange selectivity is Mg2+> Ca2+> Ba2+> Li+> Na+> K+. The ion radius of magnesium being longer than hydrogen leads to decreasing of pore volume and surface area. XRD analysis shows that Mg3SiO5(OH)4is formed after ion-exchangeable carrying out between Mg2+and Al3+, Fe3+in attapulgite rather than the structure of attapulgite clay destroying by the acid, alkali metals and alkaline earth metals. IR analysis shows that the absorption peak at3750cm-1after modification by magnesium nitrate becomes stronger. Because of Mg2+increasing, stretching vibration of-OH connecting Mg2+ become strengthenner, while the enhance of peak at1400cm-1is caused by disappearances of a large number of carbonates.(2) The attapulgite desulfurizer modified by transition metals has higher desulfurization efficiency than alkali metals in gasoline of RFCC of Lanzhou Petrochemical Company. The desulfurization rate increases significantly by transition metals Cu2+, Ag+modification attapulgite clay, reaching to50.94%.(3) Transition metal component Ag and Fe are suitable for desulfurization in MTBE. The optimum conditions for preparation of attapulgite desulfurizer are:mass fraction of Fe-based compound8%, mass fraction of Ag-based compound2.0%, calcination temperature250℃, calcination time3h, and time of passing column40min. Under normal temperature and pressure, the average sulfur content in MTBE reduces from124.87μg/g to789.38μg/g using the attapulgite desulfurizer, and the desulfurization rate is84.18%. TEM shows that the active component loading on attapulgite has a uniform dispersion, and XRD shows that there is no change in the structure after loading with active ingredient. After desulfurization, the emergence of new peaks at20=38.538is due to AgS by the reaction of active ingredient Ag and sulfur in MTBE. And through the results of XPS, we could know that the sulfur in MTBE are in the form of AgS and FeS. BET analysis shows that the pore size distribution of desulfurizer prepared under optimum conditions is between4.5and105nm, covering the structure of micropore, mesopore and macropore, which is favorable for desulfurization of MTBE. IR analysis shows that the absorption peak at1384cm-1of attapulgite desulfurizer becomes sharp, which is due to in-plane bending vibration of association hydroxyl in attapulgite and the active ingredient. |
PDF Full Text Request