Study On Presulfurization Process Of Hydro-Upgrading Catalyst For FCC Gasoline

FCC gasoline hydrotreating catalyst can realize aromatization of olefins and reduce the loss of octane number of gasoline while reducing olefin content,which is the key to produce clean gasoline meeting the national VI standard.At present,the method of in situ vulcanization is usually used,which leads to the problems of long start-up period,high initial activity of catalyst,low liquid recovery and so on,and affects the economic benefit of refinery.In this paper,a simple external sulfurization passivation method was designed.By optimizing the composition of sulfurization passivator and key sulfurization process parameters,a new pre sulfurization hydrogenation catalyst was prepared,and the reaction process conditions were optimized.The effect of the amount of sulfurizer on the aromatization performance of FCC gasoline hydrotreating catalyst was investigated.Compared with the catalyst prepared by in situ sulfurization,the out of situ sulfurization mechanism of active metals was revealed.The results show that the aromatization performance of the catalyst increases first and then decreases with the increase of the amount of sulfurizing agent.The aromatization performance of the best external sulfurizing catalyst is equivalent to that of the in-situ sulfurizing catalyst.It was found that Zn O can be vulcanized at 120℃and Ni O can be vulcanized at reaction evaluation temperature of 380℃.Ethanolamine and triethanolamine were selected as passivators respectively.The effects of the type and content of passivators on FCC gasoline hydro upgrading catalysts were investigated.It was found that the introduction of passivators could regulate the surface acidity of catalysts,shorten the stability period of catalysts and improve the aromatization performance of catalysts.The results show that triethanolamine can improve aromatization performance,increase the selectivity of p-xylene,reduce the selectivity of C9⁺aromatics,and effectively inhibit the backward shift of gasoline dry point.It was found that the sulfurized passivated catalyst prepared by triethanolamine at S:N=1:1.5 had the shortest stable period and the best aromatization performance.The effect of passivation temperature on the aromatization performance of the catalyst was investigated.It was found that the aromatization performance of the catalyst increased with the increase of passivation temperature,and the best aromatization performance was obtained when the passivation temperature was 300℃.The aromatization performance of FCC gasoline from Fushun Petrochemical Company was investigated by using the optimized sulfurization passivation hydrotreating catalyst,and the reaction conditions were optimized.The results showed that under the conditions of reaction temperature 400℃,reaction pressure 1 MPa,volume ratio of H₂/Oil 300 and space velocity1.5h^-1,the olefin conversion was 26.72%,aromatization rate was 51.56%,and liquid yield was92.80%.