As an extremely complex system, petroleum comprises not only alkanes, cyclic alkanes and aromatic hydrocarbons of different molecular weight, but also a small amount of sulfides, oxides and nitrides, as well as some trace amounts of metal compounds of iron, copper, nickel, vanadium, etc. In the process of petroleum processing, these hydrocarbon or non-hydrocarbon substances will subject such chemical reactions as cracking, condensing and coking. Now, the catalytic hydrogenation process is usually conducted by adding hydrogen into the feedstock oil under conditions of high temperature and high pressure both at home and abroad. However, with the ever-increasing contradictions between the trend of heavy crude oil and need to be light for the petroleum products, the feedstock oil to the reprocessing device is becoming heavier and inferior in quality, that finally causes some serious problems to the catalyst for hydro cracking, hydro desulfurization and catalytic cracking devices in many refineries and petrochemical plants such as coking, scaling and eventually deactivated, even influencing the catalytic bed of hydro refining and hydro cracking to fasten pressure decline, thus seriously affecting and confining the action cycle and stable operation of the devices.
The problem of catalyst deactivation is obvious especially in the hydro cracking device because of its high reacti n pressure of 15-20 MPa, high temperature of 380-420° C. and the one-lot filling of catalyst of 500-1000 tons. In some cases, the equipment has to be stopped to maintain only after 3 to 5 months' operation due to catalyst deactivation. Thus, it is an urgent task to prevent or alleviate the catalyst deactivation and enhance catalyst efficiency in hydro cracker to lengthen the action cycle to acquire more economic benefits.
The catalysts used in the process of petroleum hydrogenation are inorganic, while the feedstock involved in the hydrogenation reaction are organic materials and non-polar hydrogen. Accordingly, the contacting activity of feedstock with catalyst is relatively poor, and coke easily formed on the surface of the catalyst will affect activity of the catalyst.
There have been quite a few reports both at home and abroad on study of new hydrogenation catalysts in recent years. However, none of them addresses to the addition of catalytic active accelerant to the feedstock oil during the hydrogenation to improve the catalyst activity, the depth of catalytic hydrogenation and the yield of catalytic hydrogenation products, and weaken the reaction conditions of catalytic hydrogenation. It would be a tremendous contribution to the international catalytic hydrogenation techniques that catalytic active accelerant is applied in practical production to increase the catalyst activity and prolong the service life of the catalyst.