Desulfurization of dibenzothiophene in model fuels by oxidative adsorption method

An oxidative desulfurization adsorbent composed of mass fraction 69.8% nitric acid over silica gel was used to deeply remove dibenzothiophene from model diesel fuels.In the batch reactor,the model fuel containing mass fraction 1 000×10-6 4,6-dimethyldibenzothiophene(4,6-DMDBT) was stirred with the oxidative adsorbent at mild temperature under atmospheric pressure.The results show that the sulfur-free fuels are obtained in 90 min at 45 ℃ when the mass ratio of adsorbent to catalyst and fuel equals to 1 ∶0.75 and 1 ∶30,respectively.The aromatic hydrocarbon hardly has effect on the desulfurization rate.However,the reaction rate decreases dramatically in the water saturated fuel.The desulfurization capacity of regenerated adsorbent is almost totally recovered.Because the desulfurization reaction occurs in the pores of the adsorbent,the model fuel after desulfurization can meet the national corrosion test in China.