Study On Mechanism Of Thiophene Hydrodesulfurization On Surface Of Ni₂P

Due to the progressive depletion of conventional light oil and the insatiable need for energy in China,more people all over the world are looking forward to an immense amount of heavy oil,one of the main energy sources in 21st century.Added to this,the key challenge that must be overcome with these oils is their high original viscosity which leads to recovery,transportation and refining difficulties for efficient production and utilization.To some extent,the viscosity of heavy oil can effectively drop by the effect of aquathermolysis reactions.The hydrodesulfurization?HDS?reaction,as the last step of the aquathermolysis reaction,is of great significance to the viscosity reduction and desulfurization of heavy oil.Based on density functional theory?DFT?,this research simulated the adsorption and hydrodesulfurization of thiophene on Ni₂P?001?surface and Ni₂P?001?which is loaded on the surface of?-Al₂O₃,to determine the hydrodesulfurization reaction mechanism of thiophene on Ni₂P?001?surface and the optimal reaction path,all with the use of Dmol³module of Materials Studio?MS?simulation software.Furthermore,the effect of carrier on the mechanism of hydrodesulfurization reaction was also taken into account.The following conclusions are obtained.?1?There are 12 ways of adsorption of thiophene on Ni₂P?001?surface.When thiophene flats in three fold vacancy on Ni₂P?001?plane,the adsorption energy is largest and the adsorption configuration is most stable.?2?The hydrodesulfurization reaction network of thiophene on Ni₂P?001?surface was obtained.Hydrodesulfurization of thiophene can be divided into two methods,direct and indirect.The reaction step of direct hydrodesulfurization are as follows:C₄H₄S+H₂?C₄H₆.the possible reaction steps of indirect hydrodesulfurization are as follows:?1?C₄H₄S+H₂??,?-C₄H₆S;?2??,?-C₄H₆S+H₂?C₄H₈S;?3?C₄H₈S+H₂?C₄H₁₀.?3?For the direct hydrogenation desulfurization mechanism,the reaction activation energy is low,and elevated temperature is beneficial to improve the reaction yield.For the indirect hydrogenation desulfurization mechanism,low temperature can improve the desulfurization reaction yield.It's found that the direct method has more advantages than the indirect method.?4?When thiophene is on the surface of Ni₂P?001?which is loaded by?-Al₂O₃,the most stable adsorption configuration is three vacancy adsorption mode of flat,but the adsorption energy increases,indicating that?-Al₂O₃ as carrier of thiophene in Ni₂P?001?surface has a role in promoting.?-Al₂O₃ can promote thiophene hydrodesulfurization reaction.As a carrier,?-Al₂O₃ can promote hydrodesulfurization of thiophene.