Patent GB-768965-A (GB)
Title: Cracking heavy hydrocarbon oils
IPC: C10G51/04
Filed: 1955-01-14
Abstract: In order to obtain olefines of low molecular weight from heavy hydrocarbon oils, the oil is first vaporized and thermally cracked by contacting it with fluidized particles of inert solid at a temperature of 900 DEG  to 1100 DEG  F.; the particles are separated from the vapours, heated to a temperature of 1350 DEG  to 1700 DEG F. and made catalytically-active, and the thermally-cracked vapours are then upgraded by contacting them with the hot activated particles.  The contact material is preferably coke; this is heated by partial combustion and is activated, for the catalytic stage of the process, by treatment with steam.  Other contact materials referred to are sand, metal particles and carborundum.  Fresh <PICT:0768965/IV(b)/1> oil feed is sprayed through line 13 into transfer line 11, through which spent coke particles at 900-1100 DEG F., suspended in steam or hydrocarbon gas introduced through line 16, are flowing. Vaporization and thermal-cracking of the oil take place in line 11, and the vapours are subsequently separated from the particles in cyclone 17.  The particles pass down line 21, and are carried through transfer line 25 by air introduced through line 26. The particles are heated by combustion of coke to 1350-1700 DEG  F. in line 25; and the suspension discharges into vessel 27, where the particles are maintained as a dense fluidized bed by superheated steam introduced through line 31.  The temperature in the bed is about 1300-1500 DEG  F.; and the steam activates the particles producing carbon monoxide and hydrogen, which are removed through outlet 34.  The catalytically-active particles flow over partition 41 into zone 43 where they are stripped by gas introduced through line 45.  The catalyst particles are then transferred through bend 51 into transfer line 53, where they rise in contact with the thermally-cracked vapours withdrawn from cyclone 17 via line 19. Line 53 may be operated at about 1020 DEG  to 1200 DEG  F. with a contact time of 0.5 to 5 seconds.  For the production of gaseous olefines the temperature is higher, e.g. 1150-1350 DEG  F., and the contact time is shorter, e.g. 0.01 to 2 seconds.  The suspension is discharged into cyclone 55, and the product-vapours are withdrawn overhead, while the spent particles flow down line 59 to be mixed with fresh feed.  In some cases it may be necessary to return some of the hot particles from line 25 to line 11 via line 67.  Spent coke may be withdrawn from the system through lines 23 and 61; activated coke may be withdrawn through line 37.  Another apparatus is described wherein the thermal-cracking and combustion operations are effected in fluid bed reactors instead of transfer lines.  Specifications 551,663 and 723,149, [Group III], are referred to.ALSO:In order to obtain products such as high octane gasoline or olefines of low molecular weight from heavy hydrocarbon oils, the oil is first vaporized and thermally cracked by contacting it with fluidized <PICT:0768965/III/1> particles of inert solid at a temperature of 900 DEG  to 1100 DEG F.; the particles are separated from the vapours, heated to a temperature of 1350 DEG  to 1700 DEG F. and made catalytically-active, and the thermally-cracked vapours are then upgraded by contacting them with the hot activated particles.  The contact material is preferably coke; this is heated by partial combustion and is activated, for the catalytic stage of the process, by treatment with steam.  Other contact materials referred to are sand, metal particles and carborundum.  Fresh oil feed is sprayed through line 13 into transfer line 11; through which spent coke particles at 900 DEG -1100 DEG F., suspended in steam or hydrocarbon gas introduced through line 16, are flowing.  Vaporization and thermal-cracking of the oil take place in line 11, and the vapours are subsequently separated from the particles in cyclone 17.  The particles pass down line 21, and are carried through transfer line 25 by air introduced through line 26.  The particles are heated by combustion of coke to 1350 DEG -1700 DEG F. in line 25; and the suspension discharges into vessel 27, where the particles are maintained as a dense fluidized bed by superheated steam introduced through line 31.  The temperature in the bed is about 1300 DEG -1500 DEG F.; and the steam activates the particles producing carbon monoxide and hydrogen, which are removed though outlet 34. The catalytically-active particles flow over partition 41 into zone 43 where they are stripped by gas introduced through line 45. The catalyst particles are then transferred through bend 51 into transfer line 53, where they rise in contact with the thermally-cracked vapours withdrawn from cyclone 17 via line 19. Line 53 may be operated at about 1020 DEG  to 1200 DEG F. with a contact time of 0.5 to 5 seconds.  For the production of gaseous olefines the temperature is higher, e.g. 1150 DEG -1350 DEG F., and the contact time is shorter, e.g. 0.01 to 2 seconds.  The suspension is discharged into cyclone 55, and the product-vapours are withdrawn overhead, while the spent particles flow down line 59 to be mixed with fresh feed.  In some cases it may be necessary to return some of the hot particles from line 25 to line 11 via line 67.  Spent coke may be withdrawn from the system through lines 23 and 61; activated coke may be withdrawn through line 37.  Another apparatus is described wherein the thermal-cracking and combustion operations are effected in fluid bed reactors instead of transfer lines.  Specifications 551,663 and 723,149 are referred to.