process for the selective hydrogenation of several stages of coupespetrolieres hot in the field of species

摘要

1316080 Selective hydrogenation of pyrolyses gasoline INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS 23 July 1971 [27 July 1970] 34734/71 Heading C5E The selective hydrogenation of feedstocks boiling in the gasoline range and containing aromatic hydrocarbons, olefins, diolefins and sulphur compounds is carried out in three stages, (a) with at least 50% of the feed in the liquid phase, using a catalyst comprising a Group VIII metal; (b) in the gaseous phase using a catalyst comprising supported molybdenum and/or tungsten and having a specific surface of 20-90 mSP2/SP/g.; and (c) in the gaseous phase using a catalyst comprising supported molybdenum or tungsten and having a specific surface of 120-500 mSP2/SP/g. The feedstocks treated are derived from the thermal, catalytic, steam cracking or coking of naphtha or gas oil. The first stage (a) is carried out at 50-200‹ C. and 5-60 kg/cm.SP2/SP such that at least 50% of the effluent is liquid; suitable catalysts are fixed beds of Ni, Co, Pd or Pt on alumina, silica, silicaalumina, magnesia, clay or zeolite or suspensions of Raney nickel or cobalt. The second stage (b) is carried out at 230-360‹ C. and 25-60 kg/cm.SP2/SP using a catalyst comprising Mo or W alone or together with a Group VIII metal on a carrier such as alumina, silica, magnesia or titania; the bed can be cooled by introducing a portion of the charge or recycled material at an intermediate point in the bed. The third stage (c) is carried out at 300-390‹ C. and 10- 60 kg/cm.SP2/SP using a catalyst comprising Mo or W alone or together with a Group VIII metal on alumina or alumina-silica. The catalysts used in the second and third stages, (b) and (c), can be used in the form of sulphides and the hydrogen used in these stages can contain 200-4000 p.p.m. by volume of hydrogen sulphide.