Study On Arsenic Poisoning Of Catalytic Gasoline Hydrogenation Catalysts

Catalytic gasoline hydrodesulfurization technology is one of the main technologies of catalytic gasoline cleaning and production of gasoline blending components.And catalyst is the key point of the technology.There exists some organic arsenic in the raw materials of catalytic gasoline,which can be loaded on hydrodesulfurization catalyst,resulting in the poisoning of the catalyst.In this thesis,the concentration and type distribution of the arsenic in the catalytic gasoline of some refineries in CNPC were researched.And the results shows that the possible types of arsenide in catalytic gasoline are triethyl arsenic,diphenyl arsenic and triphenyl arsenic,etc.Triphenyl arsenic and triethyl arsenic were used as arsenide for high arsenic model oil to do arsenic poisoning experiments on the hydrodesulfurization CoMo/Al₂O₃catalyst in laboratory.And the thesis also study the industrial arsenic poisoning of PetroChina's E refinery and F refinery's CoMo/Al₂O₃ catalyst discharge agent.Hydrogenation activity of hydrodesulfurization catalyst before and after poisoning and the deactivation temperature of arsenic poisoning catalyst were evaluated by using a hydrogenation evaluation device.XRF,BET,XRD,Py-IR and NH₃-TPD analytical methods were used to characterize the physicochemical properties of hydrodesulfurization catalysts before and after arsenic poisoning.The experimental results showd that the arsenide can lead to the complete disappearance of the strong acid sites of the hydrogenation catalyst,and the total amount of the B acid sites and the L acid sites decreased,resulting in a decrease in the hydrogenation activity of the catalyst.In this thesis,we also regenerated the arsenic poisoning CoMo/Al₂O₃ catalyst discharge agent by roasting and chemical impregnation,studying the recovery of activity and the removal of arsenic.The results showd that roasting method can not remove the arsenic element from the CoMo/Al₂O₃ catalyst,and the activity of the catalyst recovered after being regenerated.The regeneration by chemical impregnation has no obvious effect on the removal of arsenic from the catalyst.