Abstract: Mild hydrocracking process can give the diesel/gasoline ratio new flexibility for refinery. The effect of the operating conditions of hydrogen partial pressure, LHSV and H2/oil on the product properties were tested. Results indicated that at the same conversion, the qualities of the wax oil and diesel fractions are all improved and the high content of the mono-aromatic is easy to react when the hydrogen partial pressure increased; when the content of single cyclic aromatic hydrocarbons with different carbon number is consistent, the aromatic with lower carbon number is more likely to react as the hydrogen partial pressure increases, while the distribution changes of the carbon number of naphthene and chain alkane are small with the hydrogen partial pressure variation. Increasing SV, little changes of the product qualities are observed at the same conversion. At higher Sv, the maximum carbon number of each hydrocarbon in wax oil is higher significantly than that at lower Sv; At the same conversion, increasing H2/oil can only cause small quality changes, higher H2/oil ratio gives higher peak of carbon number than that at lower ratios. It is recognized that at the same conversion, higher PH2 is helpful to produce high quality diesel blending component and wax oil product, while higher H2/oil and Sv are benefit to the production of wax oil with higher carbon number, which can be used as feed for FCC or catalytic cracking process.

Key words: gas oil, mild hydrocracking, operating condition, hydrocarbon composition