Patent GB-491411-A (GB)
Title: Process for the conversion of hydrocarbon oils
Filed: 1937-11-16
Abstract: The process comprises the cracking and coking of crude oil with recovery and stabilization of the vapours from the cracking and coking operations.  The crude oil to be treated is preferably topped by feeding it through lines <PICT:0491411/III/1> <PICT:0491411/III/2> 111, 114, 115 into the fractionating tower 110 of the coking operation and the unvaporized portion is collected on plate 109 and pumped through line 120 into the fractionating tower 33 of the cracking stage.  In tower 33 the products of the cracking stage and the topped crude are fractionated together to isolate (a) a final gasoline fraction which is recovered through line 45, cooler 47 and separator 50, (b) a light intermediate fraction which is bled off through line 39 and cracked in coil 6, (c) a heavy fraction which is led off from the bottom of the tower through line 34, 37 and cracked in coil 1.  The products from coils 1, 6 pass to reaction drum 5 and the total cracked products are recovered through line 10 and separator 12 where the vapours and liquids are separated, the vapours passing through line 31 into the tower 33.  The residual liquid in the chamber 12 constitutes the coking stock and is fed through line 20 and heating coil 22 into the coking chamber 100.  Vapours generated in the coking are led off through line 103 to a separator 25 (where removal of heavy fractions is aided by spraying through line 128 a light fraction collected in tower 110) and thence to the superposed fractionating tower 110 from which a light fraction is recovered overhead through line 130, cooler 132, and separator 135, and fed thence through line 144 into tower 33.  The liquid residues in the chamber 25 are recycled to the coil 22 or through line 105 into the chamber 12 or may be removed through line 107 as a final liquid product of the process.  A part of the liquid stock from the chamber 12 may be fed direct through line 23 to chamber 25. The final distillate collecting in separator 50 is fed through a further cooler 58 into an accumulator 65 and is stabilized by feeding it through lines 150, 153 and reboiler 170 into tower 158 where unstable fractions are boiled off, the stabilized gasoline being led off through lines 173, 176.  Heat for the reboiler 170 is obtained by circulating therethrough part of the hot distillate bled from tower 33 through line 39, this part being fed through lines 177, 178 to the reboiler 170 and returned through line 179 into the chamber 12. Gaseous fractions liberated in the stabilizer 158 are passed through cooler 183 to separator 190 and are then fed through lines 196, 140 to mix with gaseous fractions liberated from separator 135 and accumulator 65, the total gaseous products then passing into an absorber 70 where rich gases are recovered by absorption in part of the fraction removed through line 39 and fed through heat-exchangers 203, 206 and line 211 into the absorber 70.  Lean gases pass off through line 213 while the enriched oil is fed through lines 218, 220 into the tower 33.  The products from the reactor 5 may be cooled in the line 10 before or after passage through the pressure-reducing valve 11 by injecting cooling agents through line 13.  Operating conditions specified comprise (a) coil 1, 850-950 DEG  F. under pressure of 100-300 lb. per sq. inch, (b) coil 6, 900-1000 DEG  F. under pressure of 200-500 lb., (c) chamber 12, pressures up to 100 lb., (d) coil 22, 850-1000 DEG  F. under pressure of 25 to 200 lb. Specification 470,576 is referred to.