Patent GB-428475-A (GB)
Title: Method of converting hydrocarbons
IPC: C07C9/14
Filed: 1933-11-14
Abstract: <PICT:0428475/IV/1> In the production of a blended stabilized motor fuel from a cracked oil, hydrocarbons having 3 or 4 carbon atoms in the molecule are removed and after separation from light fractions, polymerized.  The size of the polymerization unit is reduced by eliminating from the feed thereto lighter constituents thus enabling the pressure used in the polymerization to be reduced from 600--800 lbs. to 450 lbs. per sq. inch.  The liquid fraction comprising mainly propylene and butylene with some propane and lesser amounts of butane ethylene ethane and methane is polymerized by passage through heating coils 85, 86 and a reaction coil 89, the products being cooled in an arrester 92 by a portion of the distillate from a low pressure separator 90 supplied through a line 91.  The mixed polymerized products are passed to a high pressure separator 94 from which vapours pass through a cooler 98 to the low pressure separator 90 while the liquid fraction is passed through a line 96.ALSO:A blended stabilized motor fuel is produced by cracking an oil, separating a light fraction therefrom and mixing it with a fraction obtained by compression of the gases formed in the cracking operation, to form a mixture from which hydrocarbons having 3 or 4 carbon atoms in the molecule are removed and after separation from light fractions are subjected to polymerization, the polymerized products being then added to the mixture which is rectified to produce the stabilized motor fuel.  The size of the polymerization unit is reduced by eliminating from the feed thereto lighter constituents thus enabling the pressure used in the polymerization to be reduced from 600--800 lbs. to 450 lbs. per sq. inch.  Crude oil is cracked in the vapour phase as described in Specification 412,461, i.e. by feeding it through a line 3 into a fractionating tower 4 and withdrawing reflux and oil from the bottom of the tower through a line 5 to the low temperature tube banks 8, 9, 10 of a cracking furnace 12.  The products pass to an evaporator 14 from which vapours are passed through the high temperature banks 16, 18, 19 of the cracking furnace 12 to a reaction arrester 20 in which the cracked products are cooled by direct contact with a stream of oil withdrawn from the side of the tower 4 through a line 21, cooler 22, storage tank 23, and pipe 26. The mixed products are passed to a flash tower 27 where they are mixed with residues from the evaporator 14. Vapours from the flash tower 27 are passed into the tower 4 while residues are removed to a naphtha storage tank 33.  Fractions may be removed from the side of the tower 4 through lines 35 stripper 36 and cooler 37 to a storage tank 38.  The overhead fraction is removed through a cooler 41 to a separator 42 from which condensate is returned in part as reflux through a line 45.  The gaseous fraction is then compressed by a compressor 47 and the compressed products mixed with the remainder of the condensate from the separator 42 are passed through a cooler 51 into a tank 54 from which liquid is pumped through heat exchangers 57, 58, 59 and preheater 61 to the stabilizing tower 63 designed to separate out a bottom fraction containing all the components having five or more atoms of carbon in the molecule and most of those having four atoms.  The lighter fraction is removed through a line 64 and cooler 65 to a tank 66 from which reflux is supplied to the tower 63 while the uncondensed fraction is passed to a separator accumulator 72 from which gases are removed through lines 73 to an absorption unit 74 while the liquid fraction comprising mainly propylene and butylene with some propane and lesser amounts of butane ethylene ethane and methane is polymerized by passage through heating coils 85, 86 and a reaction coil 89 the products being cooled in an arrester 92 by a portion of the distillate from a low pressure separator 90 supplied through a line 91.  The mixed polymerized products are passed to a high pressure separator 94 from which vapours pass through a cooler 98 to the low pressure separator 90 while the liquid fraction is passed through a line 96 to the flash drum 27.  The liquid separated in the low pressure separator 90 is passed to the tank 54.  The desired motor fuel is removed from the bottom of the tower 63 through heat exchangers 57, 58, 59 and coolers 107, 109 to a storage tank 110.  The gases passing from the separators 72, 90 are passed through high and low pressure absorption units 74, 112 where they are washed with distillate from the tank 23 and the enriched oil obtained is used as cooling agent in the arrester 20.  <PICT:0428475/III/1>