Removal Of Thiophene Over Titanium Silicalite Using Oxidation And Adsorption

Facing the increasingly serious environmental problems,the world has seen a more and more stringent standard of sulfur content in liquid fuels proposed in many countries.The traditional hydrodesulphurization process(HDS) becomes economically insufficient with the continuously decreasing sulfur in fuels.Currently,oxidative desulphurization(ODS) becomes the hotspot which is investigated extensively for its mild reaction condition,simple equipment, and high efficiency.However,the most popular oxidation extraction has many unsolved problems such as how to improve the existing extraction rate,reduce the cost and improve rate of oil recovery.Besides,there are other challenges like how to separate solvent and refined oil.Sulfide was removed using oxidation and adsorption,which can not only avoid the loss of oil and the decline of oil quality,but also refine oil and absorb sulfide in one step,thus reducing cost and equipment investment.Main content of this thesis are summarized as follows:â… The removal of thiophene using oxidation and adsorptionThiophene can was effectively removed by using oxidation and adsorption over Titanium Silicalite in the model gasoline.The optimal reaction conditions are the TS-lconcentration 3 g/L,the weight ratio of adsorbent to oil 0.04,the mole ratio of H₂O₂ to the sulfur 9,the reaction temperature 333 K and the pressure 101 KPa.After 2 h,the sulfur concentration in model fuels can be reduced to 5μg/g.15.5 mg sulfur can be removed by using one gram of A silicon gel.Benzene has a little effect on the removal rate of thiophene. Ethylbenzene has a negative effect on the removal rate of thiophene.But the existence of olefin will prevent the removal of thiophene.â…¡The Regeneration of the Catalyst and the Research on Reaction MechanismTitanium silicate molecular sieve with pore structure can be used as the absorbent to adsorb the oxidation products.In the absence of adsorbents,oxidation products will be preferentially adsorbed on the catalyst,which leads to the deactivation of catalyst.Catalyst and absorbents can be regenerated by the method of washing and calcication.Repeated calcination will not destroy the pore structure of absorbents and catalyst.The regenerated catalyst by calcination showed the better performance than that regenerated by washing.75% of sulfur in the system is converted to sulfate,the final product of the oxidation of thiophene.