(19)
(11) EP 0 655 492 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.10.1995 Bulletin 1995/42

(43) Date of publication A2:
31.05.1995 Bulletin 1995/22

(21) Application number: 94308703.1

(22) Date of filing: 24.11.1994
(51) International Patent Classification (IPC)6: C10G 70/04
(84) Designated Contracting States:
BE DE FR GB IT NL SE

(30) Priority: 29.11.1993 US 159028
22.04.1994 US 231559

(71) Applicant: THE BOC GROUP, INC.
Murray Hill, New Jersey 07974 (US)

(72) Inventors:
  • Ramachandran, Ramakrishnan
    Allendale, New Jersey 07401 (US)
  • Dao, Loc H.
    Bound Brook, New Jersey 08805 (US)

(74) Representative: Wickham, Michael et al
c/o Patent and Trademark Department The BOC Group plc Chertsey Road
Windlesham Surrey GU20 6HJ
Windlesham Surrey GU20 6HJ (GB)


(56) References cited: : 
   
       


    (54) Catalytic cracking process


    (57) A hydrocarbon stream is cracked in Plant A to produce a hot gaseous stream which is separated in a fractionator B. A gaseous stream containing hydrogen and C₁-C₄ hydrocarbons is taken from the fractionator B, is raised in pressure in compressor C and is cooled in a heat exchanger D. The cooled gaseous stream is separated in a demethaniser E, and an off-gas comprising hydrogen and C₁ to C₃ hydrocarbons is withdrawn from the demethaniser E. The off-gas is subjected to separation by pressure swing adsorption or temperature swing adsorption at an adsorption temperature of about 0 to about 250°C in a bed of adsorbent which selectively adsorbs ethylene and propylene, thereby adsorbing substantially all of the ethylene and propylene from the gas stream. The ethylene and/or propylene is recovered upon bed regeneration.






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