GB943239A - Improvements relating to the treatment of hydrocarbon fractions - Google Patents

Abstract

Hydrocarbon fractions boiling above 150 DEG C., e.g. heavy gas oils, are treated to reduce their content of aromatic compounds and nitrogen compounds, and are then contacted in the presence of hydrogen with a platinum group metal on a refractory oxide support at a temperature of at least 600 DEG F. and a pressure of at least 100 p.s.i.g., the temperature and space velocity being correlated to give a product boiling above 150 DEG C. having a pour point at least 5 DEG F. lower than the pour point of the feedstock. The cloud point and freezing point of the fractions may also be lowered. Suitable hydrogenation conditions are: .Temperature.600-950 DEG F .Space velocity.0.1-8 v/v/hr .Pressure.100-1500 p.s.i.g .Hydrogen :hydrocarbon mole ratio.1:1- .20 : 1.. The process may be operated with or without a net hydrogen consumption. The catalyst support may be one or more of the oxides of metals of Groups II, III and IV, preferably alumina containing 5-25% wt. silica. A minor proportion of one or more compounds of non-metallic elements of Groups III, IV and V, e.g. boron or phosphorus, may be present. The catalyst may also contain halogen, e.g. fluorine or chlorine. Further, halogen may be added to the reaction zone to increase the activity of the catalyst, either as such or in the form of a compound which decomposes to the halogen under the reaction conditions, e.g. as hydrogen halides or as halogen derivatives of aliphatic hydrocarbon having 1-4 carbon atoms. The reduction of the content of aromatics and nitrogen compounds may be effected by destroying them by catalytic hydrogenation, e.g. with a cobalt molybdate-alumina or similar catalyst. Alternatively they may be removed by a method in which they may later be recovered, for example by solvent extraction, e.g. with furfural, sulphur dioxide, or a glycol, washing with sulphuric acid, urea adduction, or adsorption, for example on silica gel or a 5<\>rA or 13<\>rA molecular sieve. Specifications 928,460, 942,237 and 943,938 are referred to.