Patent GB-870474-A (GB)
Title: Improvements in or relating to jet fuels
IPC: C10L1/04
Filed: 1959-12-08
Abstract: A liquid hydrocarbon fuel for gas turbine engines comprising C9, C10 and possibly C11 paraffins boiling within the range 200-500 DEG F. and having a luminosity number of at least 100 is obtained by contacting a hydrocarbon fraction boiling in the range 200-500 DEG F. with a dehydroaromatisation catalyst at 800-1000 DEG F. and 50-750 p.s.i.g. in the presence of hydrogen, removing aromatics from the product by solvent extraction and further reducing the aromatic content of the raffinate to obtain the desired product.  Preferably the feed such as straight run, cracked or coker naphtha or higher boiling fractions is hydrosulphurised over cobalt molybdate on alumina or nickel tungsten sulphide at 400-850 DEG F., 50-1500 p.s.i.g., 0,5-20 vol./vol./hr., and 250-6000 SCF of hydrogen per barrel.  The alkyl cyclopentanes and C6 ring naphthenes are then aromatised over platinum-alumina containing halogen and/or silica, molybdena-alumina or chromia-alumina with a feed rate of 0,7-5 vol./vol./hr. and a hydrogen rate of 4,00010,000 SCF/bbl. Suitable solvents for use in the extraction are diethylene glycol, triethylene glycol, furfural or sulphur dioxide.  The raffinate is percolated over silica gel or hydrogenated over platinum, palladium, nickel, or oxides or sulphides of molybdenum, tungsten or chromium on alumina, silica-alumina or kieselguhr, at 500-700 DEG F., 250-750 p.s.i.g., 0,210 vol./vol./hr. and 1,000-20,000 SCF of hydrogen per barrel. Isoparaffins may be desirable in the fuel to reduce the pour point and may be added or produced by isomerisation before the aromatisation or as a final treatment by contact with platinum or an aluminium chloride-hydrocarbon complex at 500-900 DEG F. and 100-500 p.s.i.g. Also a kerosene fraction (300-500 DEG F.) may be added to the aromatised product and also subjected to the solvent extraction and subsequent steps.  Luminosity number is defined by: Luminosity number = <FORM:0870474/IV (b)/1> where D T is the difference in temperature between incoming air and the combustion gases as measured in a smoke point lamp for each material at a selected amount of radiation from the flame.ALSO:A liquid hydrocarbon fuel for gas turbine engines comprising C9, C10 and possibly C11 paraffins boiling within the range 200-500 DEG F. and having a luminosity number of at least 100 is obtained by contacting a hydrocarbon fraction boiling in the range 200-500 DEG F. with a dehydroaromatisation catalyst at 800-1000 DEG F. and 50-750 p.s.i.g. in the presence of hydrogen, removing aromatics from the product by solvent extraction and further reducing the aromatic content of the raffinate to obtain the desired product.  Preferably the feed such as straight run, cracked or coker naphtha or higher boiling fractions is hydrodesulphurised over cobalt molybdate on alumina or nickel tungsten sulphide at 400-850 DEG F., 50-1500 p.s.i.g., 0.5-20 vol./vol./hr., and 250-6000 SCF of hydrogen per barrel.  The alkyl cyclopentanes and C6 ring naphthenes are then aromatised (see Group IV(b)).  Suitable solvents for use in the extraction are diethylene glycol, triethylene glycol, furfural or sulphur dioxide.  The raffinate is percolated over silica gel or hydrogenated over platinum, palladium, nickel, or oxides or sulphides of molybdenum, tungsten or chromium on alumina, silica-alumina or kieselguhr, at 500-700 DEG F., 250-750 p.s.i.g., 0.2-10 vol./vol./hr. and 1,000-20,000 SCF of hydrogen per barrel. Isoparaffins may be desirable in the fuel to reduce the pour point and may be added or produced by isomerisation before the aromatisation or as a final treatment by contact with platinum or an aluminium chloride-hydrocarbon complex at 500-900 DEG F. and 100-500 p.s.i.g. Also a kerosene fraction (300-500 DEG F.) may be added to the aromatised product and also subjected to the solvent extraction and subsequent steps.  Luminosity number is defined by: <FORM:0870474/III/1> where D T is the temperature difference between incoming air and the combustion gases as measured in a smoke point lamp for each material at a selected amount of radiation from the flame.