Study Of FCC Stock Hydrodesulfurization Catalysts

As residue mixed into FCC stock and the quality of crude oil becoming worse and worse, it's already hard to meet the environmental rules by refining product of FCC. So it is an inevitable tendency for the FCC stock hydrogenation pretreatment. Because of the importance of pore structure for heavy oil hydrosulfurization, the effect of ream agent and molding condition on the textural properties of support were investigated.Roasting tempareture and the ratio of water to pseudo-boehmite have the central influence on pore structure of support. Pore diameter gradually increase and specific surface area gradually decrease with roasting rempareture icreasing. As the ratio of water to pseudo-boehmite increase, the impact of extrusion force recedes and pore structure of support gets close to raw powder. Pore volume, pore diameter and specific surface area have maximum value when the ratio of water to pseudo-boehmite is Y+0.04. But this can not avoid the impact of extrusion force completely and the large pores are destroyed.In various reaming agents, carbon black whcih can mutual gather into chains has obviously reaming effect. When addition amount is not too high, the intensity of support will not drop mightily. In this study we choose tow kinds of CB-1 investigate their effect on pore structure. CB-1 produce more large pore because of its larger partical size. Grain diameter of CB-2 is 13nm in average, but its specific surface area is larger than A by sixty times. CB-2 has developed chain structure, so it provides larger pore volume and specific sueface area for support, besides it produce less large pore. When addition amount of CB-2 is 4x%, the pore diameter diatribution has a double-peak rudiment and presents obviously double-peak as addition amount keeps adding up. At this time there are too many large pores and the intensity of support descends rapid.Corporation of CB-2 and ration of water to pseudo-boehmite makes not only the addition amount of carbon black reduce but large pore decrease. Moreover, it can obtain such support that its pore diameter distribution centralize at 4～10nm. Prepare catalyst choose support that its pore diameter distribution centralize at 4～10nm. The catalysts are evaluated using VGO as feedstock at flow figure of the 100mL hydrotreating catalysis test unit. Investigate effection of Ni/(Ni+Mo) and the second assiatant P on activity of catalyst. The results show that catalyst has highest activity when the ratio of Ni to Ni+Mo is A+0.04 and ratio of P to MoO₃ is B+0.02.We also study the influence of pore structure on cativity of catalyst. The results indicate that catalyst has low HDS/HDN activity when its avarege pore diameter is too small. Catalyst has highest activity when its pore diameter distribution centralize at 4～10nm. When use the double-peak catalyst, because it has quite amount of large pore, HDS activity decrease a little and HDN activity decrease remarkable.