GB427632A - Process for the stabilisation of liquid hydrocarbons especially motor fuels - Google Patents

Abstract

Relates to the gum stabilization of hydrocarbon products, particularly motor fuels, without substantial reduction of their octane number; and consists in treating such hydrocarbon products in the vapour phase with gases consisting of or containing free hydrogen, while in contact with hydrogenating catalysts resistant to poisoning by sulphur, at elevated temperature and with a partial pressure of oil vapour between 40 and 80 per cent, the time of contact being not more than 50 seconds. The partial pressure of free hydrogen is, preferably, at least 20 per cent. With strongly hydrogenating catalysts pressures below 30, e.g. 10 atmospheres may be employed, with less active catalysts, pressures of 50, 100, 200 atmospheres or more may be used. Temperatures of at least 275 DEG C., e.g. 300--400 DEG C., are employed; but for initial materials consisting substantially of aliphatic hydrocarbons lower temperatures, e.g. 200--275 DEG C., may be desirable. The materials may be pretreated with adsorbents, e.g. bleaching or Fuller's earth, diatomaceous earth, silica gel, active carbon or coke. Suitable catalysts are heavy metals of the sixth group of the periodic system, especially molybdenum and tungsten; but chromium and uranium and their compounds or sulphur-immune compounds of tin, titanium, vanadium, rhenium, manganese, zinc, cadmium, aluminium, iron, nickel or cobalt, e.g. sulphides may be employed. The catalysts may be deposited on carriers. Gases containing free hydrogen may comprise mixtures of hydrogen with nitrogen, carbon dioxide, hydrogen sulphide, water vapour, methane &c., or water gas. As initial materials, benzines derived from cracking, low temperature carbonization or destructive hydrogenation operations may be employed; also benzol, toluol, kerosene and neutral portions of coal tar oils having a boiling range of benzines, or of safety aviation or marine fuels. Examples are given of the treatment of gasoline and benzines using tungsten disulphide or molybdenum sulphide as catalyst. Specifications 22147/14, 300,900, [both in Class 91], and 379,335 are referred to.