Research On Oil Deep Oxidation Desulfurization With Application Of Molecular Oxygen

Sulfur dioxide emission,which from burning sulfur gasoline and diesel,has caused serious damage to the air quality and ecological environment.As the national automobile emission standard further upgraded,fuel has been developing towards to the deep desulfurization.With the advantage of pollution-free and low energy consumption,oxidative desulfurization has gradually become a research hotspot.Schiff base metal complexes,a kind of biomimetic catalyst,have excellent capacity for oxygen storage and molecular oxygen activation at normal temperature and pressure.At present,schiff base metal complexes that encapsulated in supercage of molecular sieve have been applied to fuel desulphurization for a deep desulfurization,but the current research cannot meet the demand of pilot or industrialization application.In this thesis,the factors on catalyst sysnthesis were optimized,the desulfurization performance in suspend bed reactor was investigated,and the intrinsic kinetics of the oxidation reaction was studied.The above studies provide scientific data for pilot and industrial application.The study of catalyst synthesis found that the process of ligand entering the supercage is the limiting step of catalyst synthesis,which directly influences the cobalt content of the active component in the catalyst.Because of "Hadvall effect" and "cage effect",the solid-phase synthesis method is better than the solid-liquid phase synthesis method.Under the optimality conditions of 150 ℃ and 1 Mpa nitrogen pressure,the cobalt content is up tO 3.11%by the solid-phase synthesis method.The oxidation desulfurization process was evaluated by intermittent operation in suspend bed reactor,an optimal process was established and performed with an agent oil ratio 0.8 g·（100 ml）-1,gas flow 100 ml·min-1 and organic sulfur concentration 200 ppm at 100 ℃.The oxidation desulfurization evaluated by continuous operation are analysed through the orthogonal experiment,the optimial operation was carried out with 3.2 g catalyst,gas flow 200 mL min-1,liquid feed 4 mL·min-1 at 100 ℃.The variance analysis showed that the temperature and catalyst dosage pressed significant effect on the desulfurization.The oxidation desulfurization rate of the two operation modes reached more than 95%in air.DBTO₂,the oxidation product of DBT,was identified by HPLC.Reactive oxygen species in the reaction system is O2·-analysized by the free radical capture method.The desulfurization mechanism can be descripted that O2·-directly attack on the S atom in DBT to produces DBTO2.The Intrinsic reaction kinetics was studied respectively by power function and hyperbolic equation.The oxidation reaction was fitted for the second-order kinetics equation,which can be expressed as-d（cDBT）/dt = 17968.51 exp（-66860/RT）cDBT2.And the oxidative reaction can be fitted for the hyperbola dynamics equation,which can express as-d（cDBT）/dt=k（cDBT）n/[1+（KcDBT）N],the correlation coefficiency is gotten as R2>0.95.The model introduces the adsorption parameter K to explain the adsorption and reaction process of the catalyst,so the hyperbolic kinetic model is more suitable to describe the characteristics of Co（salen）Y oxidation desulfurization under the system.