Patent GB-1076012-A (GB)
Title: Improvements of thermal stability of jet fuels
IPC: C10L1/16
Filed: 1964-04-30
Abstract: The thermal stability of hydrocarbons, including jet fuels and isoparaffinic hydraulic fluids and lubricants, is improved by a filtration/adsorption process with optional injection of additives before and after.  The filtration/adsorption is performed by downward passage through a 20 foot bed of natural, synthetic or attapulgite clay, silica gel, fuller's earth or adsorbent catalysts (21) supported by beds of coarser inert material, a further woven cotton filter (28) removing any entrained clay from the hydrocarbon.  The hydrocarbon may previously be dried by upward passage through layers of rock salt and NaOH flakes in drier (12).  Pump (11) may pass hydrocarbon round a closed circuit so that it is repeatedly dried and filtered. The treatment as applied to jet fuel is performed at the airport, on newly delivered fuel or fuel removed from an aeroplane's tanks, to remove various dissolved and suspended impurities, which may have formed during transport. Before the filtration, possibly at the refinery, 0.0001 to 0.1% by weight of diphenyl methane; triphenyl methyl; 1,2-diphenyl ethylene; 1,1,2-triphenyl ethane; 1,1,2,2-tetraphenyl ethane and/or 1,1,2,2-tetraphenyl ethylene may be added.  These are largely removed by the filtration.  After filtration, when the hydrocarbon is circulating round circuit (31, 32, 11, 33, 31) other additives are injected by inlets (35, 36). These comprise a first class consisting of ethylene glycol monobutyl ether acetate, tributyl acetate, acetyl tributyl citrate and acetyl tri-2-ethylhexyl citrate, and a second class comprising N,N1-disalicylidene-1,2-propane diamine; N,N1 - disalicylidine - 1,2 - ethylene diamine and a proprietary polyamine mixture. 0.001 to 2% by volume of either one or more of class one additives, or a similar quantity of a mixture of 1 to 15% of a class two additive and 85 to 99% of ethylene glycol monobutyl ether acetate is added to jet fuel.ALSO:The thermal stability of hydrocarbons, including jet fuels and isoparaffinic hydraulic fluids and lubricants, is improved by a filtration/adsorption process with optional injection of additives before and after.  The filtration/adsorption is performed by downward passage through a 20 foot bed of natural, synthetic or attapulgite clay, silica gel, fullers earth or adsorbent catalysts (21) supported by beds of coarser inert material, a further woven cotton filter (28) removing any entrained clay from the hydrocarbon.  The hydrocarbon may previously be dried by upward passage through layers of rock salt and Na OH flakes in drier (12).  Pump (11) may pass hydrocarbon round a closed circuit so that it is repeatedly dried and filtered.  The treatment as applied to jet fuel is performed at the airport, on newly delivered fuel or fuel removed from an aeroplane's tanks, to remove various dissolved and suspended impurities, which may have formed during transport.  Before the filtration, possibly at the refinery, 0.0001 to 0.1% by weight of diphenyl methane; triphenyl methyl; 1,2-diphenyl ethylene; 1,1,2-triphenyl ethane; 1,1,2,2,- tetraphenyl ethane and/or 1,1,2,2-tetraphenyl ethylene may be added. These are largely removed by the filtration.  After filtration, when the hydrocarbon is circulating round circuit (31, 32, 11, 33, 31) other additives are injected by inlets (35, 36).  These comprise a first class consisting of ethylene glycol monobutyl ether acetate, tributyl acetate, acetyl tributyl citrate and acetyl tri-2 ethylhexyl citrate, and a second class comprising N, N1-disalicylidene-1,2-propane diamine; N, N1-disalicylidene-1,2 ethylene diamine and a proprietary polyamine mixture.  0.001 to 2% by volume of either one or more of class one additives, or a similar quantity of a mixture of 1 to 15% of a class two additive and 85 to 99% of ethylene glycol monobutyl ether acetate is added to jet fuel.