GB1141809A - Improvements relating to the desulphurisation and hydrogenation of aromatic hydrocarbons - Google Patents

Abstract

1,141,809. Desulphurization and hydrogenation of aromatic compounds. BRITISH PETROLEUM CO. Ltd. 29 Sept., 1966 [4 Oct., 1965], No. 41940/65. Heading C5E. Aromatic hydrocarbon feedstocks containing 1-50 p.p.m. wt. sulphur are desulphurized without appreciable hydrogenation by passing the feedstock in the liquid or vapour phase over supported nickel at an elevated temperature and pressure in the presence of hydrogen such that the sulphur combines with the nickel but no substantial amount of H 2 S is formed, the equilibrium H 2 partial pressure being greater than the minimum necessary to prevent catalyst deactivation but less than that at which 10 mole per cent hydrogenation of the aromatic hydrocarbons occurs. The preferred feedstock is benzene containing not more than 10 p.p.m. wt. S. The nickel may be supported on the refractory oxides of Group II to V elements or on kieselguhr, pumice or, preferably, sepiolite. The desulphurized feedstock may then be hydrogenated in two stages, both using supported Ni catalysts in which not less than 90% wt. and not more than 99% wt. of the feedstock is hydrogenated in the first stage, the hydrogenation being completed in the second stage; the first stage is cooled by liquid recycle (e.g. cyclohexane) and the second stage is uncooled. Each stage may be carried out in mixed phase and the reactor outlet temperature of the second stage should be less than that of the first stage. The hydrogen used in the process of the invention may be commercially pure or may be mixed gas such as steam reformer tail gas or catalytic reformer off gas preferably containing at least 50 mole per cent H 2 . A H 2 partial pressure of 0.5 p.s.i. and 400 ‹F. limits hydrogenation of the aromatic hydrocarbon during the desulphurization to 5 mole per cent.