ES270829A1 - Process for producing jet fuel hydrocarbons - Google Patents

Abstract

Paraffinic jet fuels are obtained from feedstocks containing cyclic hydrocarbons boiling in the jet fuel range by contact with hydrogen at 300-400 DEG C. and at least 68 atmospheres, e.g. 68-170 atmospheres, in the presence of a catalyst comprising a refractory inorganic oxide, 0.01-2% by weight of a platinum group metal and 0.75-1.5% by weight (calculated as chlorine) of combined chlorine as the sole halogen component, whereby cyclic hydrocarbons are converted to paraffins by ring-opening and hydrogenation. The space velocity may be 0.5-10 vol./vol./hr. and the hydrogen mol. ratio 4-50 : 1 and the feed may boil in the range 52-231 DEG C. Normal paraffins are preferably removed from the feed, e.g. by molecular sieves, and unconverted cyclic hydrocarbons recovered from the product and recycled. The catalyst is preferably prepared from alumina calcined for at least one hour at 454-566 DEG C. and thereafter at 593-760 DEG C. to reduce the volatile matter to below 2%. Platinum and chlorine are then incorporated and the composite calcined at 204-316 to reduce the volatile content to below 5% and then at 371-538 DEG C. to reduce it to below 2%. The oxide may alternatively be silica, zirconia, magnesia, boria, thoria, titania, strontia or mixtures of oxides.ALSO:A hyrogenation catalyst comprises a refractory inorganic oxide, 0,01-2% by weight of a platinum group metal and 0,75-1,5% by weight (calculated as elemental chlorine) of combined chlorine as the only halogen component. The oxide is preferably alumina but may also be silica, zirconia, magnesia, boria, thoria, titania, strontia or mixtures of oxides. Alumina is preferably calcined first at 454-566 DEG C. for at least one hour and thereafter at 593-760 DEG C. for a time to reduce the volatile content to below 2%. Chloride may be added before or after impregnation with the metal by means of hydrogen chloride, aluminium chloride or ammonium chloride or preferably during impregnation of the metal by using chloroplatinic acid, ammonium chloroplatinate or chloroplatinous acid together with hydrogen chloride. The composite is finally calcined at 204-316 DEG C. for at least one hour, to reduce the volatile content to below 5% and then at 371-538 DEG C. for at least a further hour to reduce the volatile content to below 2%.