Process for pyrolysis of hydrocarbons

• US 5,271,827 A
• Filed: 06/24/1992
• Issued: 12/21/1993
• Est. Priority Date: 11/29/1990
• Status: Expired due to Term

• Current Assignee: Stone & Webster Process Technology, Inc. (Technip Energies NV)
• Original Assignee: Stone & Webster Engineering Corporation
• Inventors: Woebcke, Herman N.
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): GRIFFIN, WALTER DEAN
• Application Number:
  US07/902,913
• Time in Patent Office: 545 Days
• Field of Search: 208/132, 585/648, 585/650
• US Class Current: 208/132
• CPC Class Codes: C10G 9/002 Cooling of cracked gases
• CPC Class Codes: C10G 9/20 Tube furnaces
• CPC Class Codes: F28D 2021/0075 for syngas or cracked gas cooling systems cooling of cracked gas C10G9/002
• CPC Class Codes: F28D 7/12 the surrounding tube being closed at one end, e.g. return type F28D7/14 takes precedence

Abstract

An improved hydrocarbon pyrolysis process and apparatus for the production of ethylene comprising a novel furnace comprised of an unfired superheater radiant section and a fired radiant section, adiabatic tube reactor and quench boiler is provided.

Claims

1. A process for producing olefins from hydrocarbon feed selected from naphtha, atmospheric gas oils and vacuum gas coils comprising the steps of

delivering hydrocarbon feed to process coils passing through an unfired radiant superheater zone heated with radiant heat from the flue gases of a downstream fired radiant zone;

and

delivering the hydrocarbon feed from the unfired radiant superheater zone to a fired radiant zone in the process coils extending from the superheater zone through the fired zone.

2. A process as in claim 1 further comprising the step of delivering the hydrocarbon feed from the fired radiant zone to an adiabatic reactor.

3. A process as in claim 2 further comprising the step of heating the hydrocarbon feed by convection before delivering the feed to the unfired radiant superheater zone.

4. A process as in claim 3 further comprising the step of indirectly quenching the effluent from the adiabatic reactor to terminate the reactions in the effluent.

5. A process as in claim 4 wherein said adiabatic reactor is in a venturi configuration and reduces the hot product gas velocity from the fired radiant zone from about 800 to about 250 ft/second.

6. A process as in claim 2 wherein the firebox temperature in the unfired radiant superheater is less than 1850°

F., the coil tube metal temperature is less than 1450°

F. and the conversion of the hydrocarbon feed is less than 10%;

the firebox temperature of the fired radiant zone is less than 2300°

F., the coil tube metal temperature is less than 1865°

F. and the conversion of the hydrocarbon feed is less than 65%.

7. A process as in claim 4 wherein the tube metal temperature in the adiabatic reactor is less than about 1650°

F. and the hydrocarbon conversion is about 90%.

8. A process as in claim 7 wherein the residence time in the unfired radiant superheater zone is about 80 to 130 milliseconds;

the residence time in the fired radiant zone is about 40 to 90 milliseconds and the residence time in the adiabatic reactor is less than about 30 milliseconds.

9. A process as in claim 8 wherein the fired radiant zone is fired at about 2500 Btu/lb of hydrocarbon and the conversion of hydrocarbon feed is at least 90%.

10. A process for producing olefins from hydrocarbon feed selected from naphtha, atmospheric gas oils and vacuum gas oils comprising the following steps:

delivering hydrocarbon feed to process coils passing through an unfired radiant superheater zone heated with radiant heat from the flue gases of a downstream fired radiant zone to convert less than 20% of the hydrocarbon feed; and

delivering the partially converted hydrocarbon feed from the unfired radiant superheater zone to a fired radiant zone in process coils extending from the superheater zone through the fired radiant zone to provide an exit conversion of said feed of less than 65%.