GB543464A - Improvements in or relating to the catalytic cracking of hydrocarbon oils - Google Patents

Abstract

543,464. Cracking oils. STANDARD OIL DEVELOPMENT CO. June 27, 1940, No. 10983. Convention date, Aug. 26, 1939. [Class 32] In catalytic cracking processes of the kind in which a suspension of oil vapours and catalyst is passed through the reaction zone, the catalyst is separated from the cracked vapours and without regeneration used in suspension in a further stream of oil which is cracked independently of the first stream. The fresh catalyst is preferably used to crack a refractory oil and is then used to crack an oil more amenable to cracking. A virgin oil or clean condensate supplied by pump 10 is vaporized in a coil 12 and the vapours after separation of liquid residues in separator 15 are. mixed in line 17 with unregenerated catalyst supplied from a hopper 22 by a conveyer 21. The suspension is passed through a reactor 18 and the vapours are separated from catalyst in a cyclone separator 24 and passed to the fractionating tower 27 from which gasoline fractions are recovered overhead through condenser 29 to receiver 30. The separated catalyst may in part be returned to the hopper 22 where it is mixed with fresh catalyst and re-used without regeneration in the reactor 18. 'The major part of the catalyst is passed to a purging zone 36 where residual vapours are removed by steam or evacuation and passed through line 38 to mix with the cracked vapours in line 76. The catalyst is then regenerated in known manner in regenerator 43 by regenerating gases fed through line 41 and is carried in suspension in the gases to a cyclone separator 45 where the catalyst is separated and passed to a purging chamber 48. From this chamber part of the catalyst may be returned through line 53 to hopper 22 but it is mainly passed by conveyer 51 to hopper 52 from which is charged to reaction chamber 61 where it is used to crack a separate stream of oil less amenable to cracking, e.g. cracked oil fed through line 65 from an extraneous source or the reflux condensate fed from the bottom of tower 27 through line 56. This oil is vapourized in coil 58 and separator 62 and then, admixed with catalyst from hopper 52, fed to the reaction chamber 6. The cracked vapours pass to cyclone separator 69, and thence through line 70, 26 to the tower 27. Catalyst separated in the cyclone chamber 69 is fed without re-generating back to the hopper 52 or through line 71 to hopper 22 or in part through line 12 to purging and regenerating chambers 36, 43. Part of the cracked vapours removed from reactor 61 may be passed through line 73 and injected into the stream of oil passing into coil 58 or, mixed with vapours passing from the cracking zone 18 fed through line 75 to coil 12.