| 摘要 |
Petroleum-derived feedstocks are treated at elevated temperatures and pressures in the presence of hydrogen and in contact with a bed of porous catalytic particles. In accordance with the invention, each of the catalytic particles is specially shaped as a cylinder of polylobate cross-section having bluntly rounded, concave, interlobular interstices and in conformity with a selected combination of values of three defining parameters. The particle shape is further characterized as being substantially straight-sided and as having a geometric surface-to-volume ratio in the range of about 40 to about 95 in 2/in3. When the catalyst particle cross-section is selected to be circumscribed by a rectangle, the shorter side of the rectangle is about 70% as long as the longer side of the rectangle for all preferred combinations of values of the defining radial parameters. Further, when the entire catalyst particle is circumscribed by a right circular cylinder of the same length as the particle, the particle itself is in contact with the cylinder along three longitudinal elements and occupies about 55% of the volume of the cylinder.
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