The Research On Hydrodesulfurization In Coking Crude Benzol

After entering the 21st century,with the the rapid development of organic synthesis industry,the demand for pure benzene has increased.But the growing shortage of oil resources,has been severely restricted the production of crude benzene oil,so the Coking Crude Benzol as another sources of pure benzene is getting more important.At the same time,the quality requirements on the environment are getting higher,and the restrictions of sulfur content in the oil are becoming more stringent.So the most critical process of coking benzene purification, including the removal of thiophene inactive substances gradually become a research hotspot.This article firstly usedγ-Al₂O₃ as the carrier to investigate the influence of the impregnated order of CoMo catalysts,the molar ratio of Co/Mo and the mass fraction of CoO+MoO₃ on the catalyst activity;then the CoMo/γ-Al₂O₃ hydrodesulfurization catalysts are modified by chelating agents,and get the evaluation of catalyst activity after sulfidation by-step.Using N₂-TG and XRD characterization to explain the differences of the catalytic activity;finally,it also studied the influence of the mass fraction of TiO₂ in the composite of the support and the molar ratio of the Citric Acid(CA) /Co on the activity of the catalyst in the modified CoMo/TiO₂-γ-Al₂O₃ catalyst,and compare with the soon-industrialization CoMo catalyst of the catalytic activity and the catalytic life.Through this experiments,we can get the following conclusions:(1)Three different orders of impregnation of CoMo catalyst have a big impact on activity.When Co is impregnated after Mo,the catalyst can get more CoMoS phase,and so the activity is higher;(2)Diethylenetriamine(dien),Triethylenetetramine(trien),and Tetraethylenepent-amine (TEPA) with the similar structure,are used to modify the CoMo/γ-Al₂O₃ catalyst.And we find the effect of TEPA is best,but its overall activity was lower than the un-modified catalyst; (3)Using Ethylene glycol bis(2-aminoethyl)tetraacetic acid(EGTA),TEPA and CA having the similar chelate formation equilibrium constants with Co to modified the CoMo/γ-Al₂O₃ catalyst.And the effect of CA is best;(4)When a certain amount of TiO₂ is modified the CoMo/γ-Al₂O₃ catalyst,the activity was higher than the activity of CoMo/γ-Al₂O₃ catalyst.But because the carrier TiO₂ has too low surface area,excessive TiO₂ can make the overall activity CoMo/TiO₂-γ-Al₂O₃ lower;(5)After modified CoMo/TiO₂-γ-Al₂O₃ catalysts by CA,we find that the activity is close to 100%under 240℃,and its overall activity and stability is not lagging behind campared with the industrial CoMo/γ-Al₂O₃ catalyst.