| 摘要 |
1304073 Lubricating oils SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 30 April 1970 [2 May 1969] 20931/70 Heading C5E [Also in Divisions B1 and G3] In a process for preparing a lubricating oil by catalytic hydrogen treatment followed by at least one physical separation step the viscosity index is controlled by measuring a physical property of the process stream, after the hydrogen treatment but before the last physical separation step, which property correlates with the viscosity index of the finished lubricating oil, comparing this measured value with a predetermined set value and adjusting one or more process conditions of the hydrogen treatment so that the difference between the measured and set values is reduced. The physical property measured is suitably the refractive index, using a continuous or differential refractometer, or density after the process stream has been degassed. The hydrogen treatment can be carried out in two stages with the physical property being measured between the first, more severe stage, i.e. hydrocracking or hydrotreating, and the second, milder stage, e.g. hydrofinishing. The property can be measured intermittently or continuously by hand or automatically, the signal corresponding to the measurement being supplied to a controller which operates a correcting unit pneumatically, electrically, electronically, mechanically or hydraulically. The correcting unit alters the process conditions, e.g. the reaction temperature by regulating the amount of fuel used to heat the reactor or the amount of hydrogen injected for interstage cooling of the reactor, the pressure in the reactor or the space velocity by regulating the feed supply. The physical separation step which follows the measurement of the property can be an atmospheric and/or vacuum distillation or a solvent dewaxing. A first meter, connected to a first controller, can be provided in the supply line from the hydrogenation zone to a distillation column from which the bottoms is passed to a dewaxing unit and a second meter can be provided in the discharge line from the dewaxing unit; the measured property of the dewaxed oil being compared with a set value in a second controller which then establishes the set value for the first controller. The lubricating oils produced can be distillate or residual fractions. The hydrogenation catalysts used in the examples comprise Co and Mo on alumina containing 6À5 wt. per cent F or on silica-alumina, Ni and W on alumina containing 6À5 wt. per cent F and Ni and W on alumina; these catalysts are sulphided using H 2 S in hydrogen before use. |
