Reforming exchanger system with intermediate shift conversion

• US 8,545,775 B2
• Filed: 10/20/2011
• Issued: 10/01/2013
• Est. Priority Date: 10/20/2011
• Status: Active Grant

• Current Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Original Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Inventors: Singh, Shashi, Gursahani, Kamal, Burlingame, Robert, Weeks, Tim, Gosnell, Jim, Malhotra, Avinash
• Primary Examiner(s): Singh, Prem C
• Assistant Examiner(s): YOUNG, NATASHA E
• Application Number:
  US13/277,809
• Publication Number:
  US 20130099166A1
• Time in Patent Office: 712 Days
• Field of Search: 422/129, 422/187, 422/600, 422/625, 422/148, 423/644, 423/648.1, 48/61, 481/271, 481/273, 481/275, 481/277
• US Class Current: 422/625
• CPC Class Codes: B01J 2208/00176 outside the reactor
• CPC Class Codes: B01J 2208/00265 Part of all of the reactants being heated or cooled outside the reactor while recycling
• CPC Class Codes: B01J 2208/00371 gaseous
• CPC Class Codes: B01J 2219/0004 Processes in series
• CPC Class Codes: B01J 8/025 in a cylindrical shaped bed
• CPC Class Codes: B01J 8/0285 Heating or cooling the reactor for tubular reactors in furnaces B01J8/062
• CPC Class Codes: B01J 8/06 in tube reactors; the solid particles being arranged in tubes
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 3/382 Multi-step processes
• CPC Class Codes: C01B 3/48 followed by reaction of water vapour with carbon monoxide

Abstract

A reforming exchanger system for syngas production is provided. The reforming exchanger system can have a first and a second reforming exchanger, each with a shell-and-tube configuration, and a shift reactor located intermediate to the first and second reforming exchangers to reduce carbon monoxide concentration in the outlet gas. Processes for forming syngas using the reforming exchanger systems described herein are also provided.

Claims

1. A reforming exchanger system comprising:

a first reforming exchanger comprising;

an elongated shell having a first end and a second end;

a shell side fluid inlet adjacent the first end of the first reforming exchanger for receiving a first hot gas feed;

a tube side fluid inlet adjacent the second end of the first reforming exchanger for receiving a reactant feed gas;

a shell side fluid outlet fluidly isolated from the tube side fluid inlet by a tube sheet adjacent the second end for discharging a first gas mixture from the first reforming exchanger; and

a tube bundle comprising a plurality of tubes, wherein the tubes have an inlet end secured to the tube sheet for receiving the reactant feed gas and an outlet end adjacent the shell side fluid inlet for discharging a first reformed product gas into the hot gas feed to form the first gas mixture;

a shift reactor comprising a bed of shift catalyst for converting carbon monoxide in the first gas mixture to carbon dioxide to form a reduced carbon monoxide gas mixture; and

a second reforming exchanger comprising;

an elongated shell having a first end and a second end;

a shell side fluid inlet adjacent the first end of the second reforming exchanger for receiving a second hot gas feed;

a tube side fluid inlet adjacent the second end of the second reforming exchanger for receiving the reduced carbon monoxide gas mixture;

a shell side fluid outlet fluidly isolated from the tube side fluid inlet by a tube sheet adjacent the second end for discharging a second gas mixture from the second reforming exchanger; and

a tube bundle comprising a plurality of tubes, wherein the tubes have an inlet end secured to the tube sheet for receiving the reduced carbon monoxide gas mixture and an outlet end adjacent the shell side fluid inlet for discharging a second reformed product gas into the second hot gas feed to form the second gas mixture.

2. The system of claim 1, further comprising a longitudinal shell side flow path for the first gas mixture in the first reforming exchanger, the second gas mixture in the second reforming exchanger, or both.

3. The system of claim 1, further comprising catalyst-bearing monolithic structures disposed within the tubes of one or both of the first and second reforming exchangers.

4. The system of claim 3, wherein the tubes have an Lt1Dt ratio of at least about 300, wherein Lt is the length of the catalyst bearing portion of the tubes and Dt is the inside diameter of the tubes.

5. The system of claim 1, wherein the shift catalyst is contained in a catalyst support grid.

6. The system of claim 1, wherein the shift catalyst is in the form of spheres, rings, or pellets.

7. The system of claim 1, further comprising a flow distributor disposed between the shell side fluid inlet and the outlet end of the tube bundle of one or both of the first and second reforming exchangers.

8. The system of claim 1, wherein the shift reactor is located intermediate to the first and second reforming exchangers.

9. A process for the production of syngas in a reforming exchanger system comprising a first reforming exchanger, a shift reactor, and a second reforming exchanger, wherein the process comprises:

providing a reactant feed gas to the first reforming exchanger;

at least partially reforming the reactant feed gas in the first reforming exchanger to produce a first gas mixture;

directing the first gas mixture to the shift reactor;

passing the first gas mixture through a shift catalyst bed contained within the shift reactor to selectively convert carbon monoxide in the first gas mixture to carbon dioxide to produce a reduced carbon monoxide gas mixture;

directing the reduced carbon monoxide gas mixture to the second reforming exchanger; and

at least partially reforming the reduced carbon monoxide gas mixture in the second reforming exchanger to produce a second gas mixture.

10. The process of claim 9, wherein each of the first and second reforming exchangers comprise an elongated shell having first and second ends and a flow path of the first and second gas mixtures from the first end to the second end on the shell side of the first and second reforming exchangers, respectively, is longitudinal.

11. The process of claim 9, wherein a temperature of the reactant feed gas is from about 300°

C. to about 450°

C.

12. The process of claim 11, wherein a temperature of the reactant feed gas is from about 350°

C. to about 400°

C.

13. The process of claim 9, wherein the temperature of the reduced-CO gas mixture directed to the second reforming exchanger is from about 400°

C. to about 580°

C.

14. The process of claim 13, wherein the temperature of the reduced-CO gas mixture directed to the second reforming exchanger is from about 440°

C. to about 540°

C.

15. A syngas reforming exchanger system comprising:

a first reforming exchanger comprising;

an elongated shell having relatively high and low temperature ends;

a shell side fluid inlet adjacent the high temperature end of the first reforming exchanger for receiving a first hot gas feed;

a tube side fluid inlet adjacent the low temperature end of the first reforming exchanger for receiving a reactant feed gas;

a shell side fluid outlet fluidly isolated from the tube side fluid inlet by a tube sheet adjacent the low temperature end for discharging a first gas mixture from the first reforming exchanger; and

a tube bundle comprising a plurality of tubes, wherein the tubes have an inlet end secured to the tube sheet for receiving the reactant feed gas and an outlet end adjacent the shell side fluid inlet for discharging a first reformed product gas into the first hot gas feed to form the first gas mixture;

a shift reactor comprising a bed of shift catalyst for converting carbon monoxide in the first gas mixture to carbon dioxide to form a reduced carbon monoxide gas mixture; and

a second reforming exchanger comprising;

an elongated shell having relatively high and low temperature ends;

a shell side fluid inlet adjacent the high temperature end of the second reforming exchanger for receiving a second hot gas feed;

a tube side fluid inlet adjacent the low temperature end of the second reforming exchanger for receiving the reduced carbon monoxide gas mixture;

a shell side fluid outlet fluidly isolated from the tube side fluid inlet by a tube sheet adjacent the low temperature end for discharging a second gas mixture from the second reforming exchanger;

a tube bundle comprising a plurality of tubes, wherein the tubes have an inlet end secured to the tube sheet for receiving the reduced carbon monoxide gas mixture and an outlet end adjacent the shell side fluid inlet for discharging a second reformed product gas into the second hot gas feed to form the second gas mixture.

16. The system of claim 15, further comprising a longitudinal shell side flow path for the gas mixture in one or both of the first and second reforming exchangers;

catalyst-bearing monolithic structures disposed within the tubes of one or both of the first and second reforming exchangers; and

a flow distributor disposed between the shell side fluid inlet and the outlet end of the tube bundle of one or both of the first and second reforming exchangers.

17. The system of claim 16, wherein the tubes have an Lt/Dt ratio of at least about 300, wherein Lt is the length of the catalyst bearing portion of the tubes and Ot is the inside diameter of the tubes.

18. The system of claim 15, wherein the shift catalyst is contained in a catalyst support grid.

19. The system of claim 15, wherein the shift catalyst is in the form of spheres, rings, or pellets.

20. The system of claim 15, wherein the shift reactor is located intermediate to the first and second reforming exchangers.