Study On Preparation And Hydrogenation Performance Of Sulfur-Tolerant Supported Nickel Catalyst

Solvent oil is one of the five major petroleum products,which has a wide range of applications and is closely related to people's lives.With the increasing awareness of environmental protection and the gradual emphasis on energy efficiency,the quality of solvent oil products has higher requirements.Reducing the sulfur and nitrogen content and aromatic hydrocarbon content in oil products shows extremely important practical significance.Solvent oil production process mostly adopts two-stage hydrogenation process.After the first step of desulfurization and nitrogen removal,there will still be a very small amount of sulfide in the oil,so the traditional noble metal catalyst will inevitably be affected by sulfur poisoning in the second stage of hydrogenation process.Therefore,it is very important to improve the sulfur resistance of the catalyst and reduce the cost of the catalyst.In this paper,Ni/?-Al₂O₃ catalyst was modified,and the sulfur-resistant effect of sulfur-resistant catalyst obtained by different modification methods was explored,which provided theoretical guidance for the preparation of high sulfur-resistant catalyst.The second metal(Zn,Mg,Fe,Cu)was introduced into Ni/?-Al₂O₃ catalyst by metal modification.The effect of metal additives on the sulfur resistance of Ni/?-Al₂O₃ catalyst was investigated.The results show that the introduction of Mg and Zn has the most obvious effect on the sulfur resistance of the original catalyst,while Fe and Cu have a negative effect on the sulfur resistance of the catalyst.The results of H₂-TPR analysis showed that Mg and Zn metal additives were mainly introduced to modify the active component Ni to increase the reduction degree,and alkali metal also had adsorption effect on thiophene.A series of Ni/USY-Al₂O₃ catalysts with different USY content were prepared.The sulfur tolerance time of Ni/USY-Al₂O₃ catalyst was investigated by changing the content of USY zeolite and the acidity of catalyst carrier.The results showed that the higher the content of USY zeolite in Ni/USY-Al₂O₃ catalyst,the better the sulfur tolerance effect of the catalyst,the better the stability of the catalyst and the lower the deactivation rate.At the same time,naphthene cyclomerization was observed due to the increase of acidityThe Ni/?-Al₂O₃ catalyst and 40wt%USY-Al₂O₃ carrier were mixed by mixed loading.The evaluation results showed that isomerization still occurred and the sulfur tolerance time of Ni/?-Al₂O₃ catalyst was prolonged.Because USY zeolite has the ability to adsorb and desulfurize thiophene,USY and Ni compete to adsorb thiophene,and there is no thiophene in the product,and hydrogen sulfide in the tail gas is not detected.This indicates that hydrogenolysis of thiophene occurs on Ni/?-Al₂O₃ catalyst to produce hydrogen sulfide poisoning catalyst.USY zeolite can adsorb thiophene,which reduces the contact chance between Ni/?-Al₂O₃ catalyst and thiophene,thus realizing sulfur tolerance.Enhancement of energy.On the basis of the above studies,the toluene hydrogenation and sulfur resistance of the calcined Ni/USY-Al₂O₃ catalyst were investigated.It was found that the toluene hydrogenation and sulfur resistance of the calcined catalyst decreased significantly compared with those of the non-calcined catalyst.Furthermore,Ni/10wt%USY-Al₂O₃ catalyst was selected to investigate the effect of calcination temperature on the sulfur resistance of the catalyst.It was found that the sulfur resistance of the catalyst increased gradually with the decrease of calcination temperature,but it was much lower than that of the catalyst without calcination.It was found that calcination of the catalyst reduced the toluene hydrogenation and sulfur resistance of nickel-based catalysts,and that the Ni/USY-Al₂O₃ catalyst with 40%USY zeolite content had the best hydrogenation activity and sulfur resistance without calcination.