GB708244A - Improvements relating to the catalytic desulphurisation of petroleum hydrocarbons - Google Patents

Abstract

<PICT:0708244/III/1> Petroleum hydrocarbons are catalytically desulphurized by treatment in the presence of a sulphur-resistant dehydrogenation-hydrogenation catalyst at an elevated temperature and pressure, so that the dehydrogenation of naphthenes contained in the feedstock is effected to provide not more hydrogen than is required to convert organically combined sulphur to hydrogen sulphide and to maintain the pressure in the reaction zone, cooling the vaporous products, separating the liquefied components from the gaseous components, further cooling the gaseous components to form a desulphurized liquid product and a hydrogen-rich gas, and recycling this gas to the reaction zone to constitute the whole of the hydrogen supplied thereto. The process may be carried out at a pressure of 50-200 p.s.i. and a temperature of 750-800 DEG F. The preferred catalyst is cobalt molybdate or mixtures of the oxides of cobalt and molybdenum. The process may be carried out in a static bed reactor or by using a moving catalyst bed or a fluid catalyst. In an example, treatment of a blend of kerosine, naphtha and sulphur dioxide-kerosine extract is described. In the drawing, vapours leave the reactor 10 via line 11 and are cooled in a waste heat boiler 13, from where they pass to column 14. Condensate leaves the base of the column via line 20 and the vapours leaving the column are cooled in cooler 16 or heat exchanged with the feed, and then passed to vessel 17, from which recycle gas is led by line 18 and desulphurized product from line 19 or via line 23 to the top of column 14 to act as reflux. Part of the vapours from reactor 10 may also be passed direct via line 24 to the base of column 14 as a stripping medium.