| 摘要 |
The hydrocracking of a hydrocarbon oil boiling at least predominantly above 204 DEG C. and containing nitrogenous impurities is effected in two stages in the first of which it is contacted with hydrogen and a nitrogen-resistant hydro-refining catalyst and the ammonia formed is removed, the effluent is fractionated together with the liquid effluent from the second stage to recover a product having an end point between 204 DEG and 232 DEG C. and a heavier fraction boiling above this up to at least 343 DEG C. and this heavier fraction is contacted in the second stage with hydrogen and a nitrogen sensitive hydrocracking catalyst and the liquid effluent passed to the fractionating zone. The feed may be a heavy vacuum gas oil or recycle stock, or a light gas oil or kerosine. This is contacted in the first stage with 178-1425 normal litres of hydrogen per litre of feed at 260 DEG -538 DEG C., 6,8-204 atmospheres and 0,5-10 vol./vol./hr. over a molybdena-alumina catalyst, e.g. containing 4-45% molybdenum and if desired 0,2-10% nickel, cobalt or iron, the support containing not more than 12% silica. A heavy fraction is also separated in the distillation and recycled to the first stage or passed in part to the second stage in an amount so that the total feed to the second stage contains not more than 5 p.p.m. of nitrogen. The second stage is effected at 260 DEG -510 DEG C., 6,8-204 atmospheres and 1-15 vol./vol./hr. with 178-1070 normal litres of hydrogen per litre of feed using a catalyst containing a Group VIa and/or VIII metal on a support containing silica with 12-25% alumina, and optionally zirconia. This catalyst may contain 0,5-10% of a Group VIa metal, 0,2-10% of an iron group metal or 0,1-5% of a platinum group metal and if both a Group VIII and a Group VIa metal these will be in a weight ratio of 0,05-5:1. |
