DFT study on the sequential desulfurization mechanism of reactive adsorption desulfurization

• 1、State Key Laboratory of Heavy Oil processing, China University of Petroleum (Beijing), Beijing 102249

Abstract：In this paper, DFT is used to study on sequential mechanism of thiophene desulfurization. Calculations show that, on Ni(100) surface, hol-0、hol-45 and top-0 are three preferred desulfurization path for thiophene. Especially thiophene tends to desulfurization most easily on hol-0 which has a medium adsorption strength. Comparison between ZnO and Zn show that activity energy of 2.50eV is required when H2S has a desulfurization reaction on ZnO. But only 2.34 eV is needed when on Zn. Therefore, H2S is more likely to react with Zn with products ZnS and H2. The reduction reaction of NiS and the adsorption H2S process of ZnO all need more activity energy (2.71 eV and 2.50 eV respectively), comparing with the lower activity energy of thiophene desulfurization on Ni surface (average 0.49 eV). So the reaction is difficult to happen; and this is against with the experimental phenomenon that adsorption of H2S for ZnO is a rapid reaction and thiophene desulfurization on Ni surface is the control step of rate. In sum, sequential mechanism of desulfurization can not reflect the true reaction accurately.

Keywords： thiophene reaction adsorption mechanism of desulfurization DFT