Systems and methods for producing syngas and products therefrom

• US 8,889,037 B2
• Filed: 02/01/2011
• Issued: 11/18/2014
• Est. Priority Date: 02/01/2011
• Status: Active Grant

• Current Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Original Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Inventors: Singh, Shashi, King, Keith
• Primary Examiner(s): Silverman, Stanley
• Assistant Examiner(s): IQBAL, SYED TAHA
• Application Number:
  US13/019,027
• Publication Number:
  US 20120195817A1
• Time in Patent Office: 1,386 Days
• Field of Search: 252/373, 481/97.R, 422/146
• US Class Current: 252/373
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0244 the reforming step being an autothermal reforming step, e.g. secondary reforming processes
• CPC Class Codes: C01B 2203/025 containing a partial oxidation step
• CPC Class Codes: C01B 2203/0261 containing a catalytic partial oxidation step [CPO]
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 2203/0288 containing two CO-shift steps
• CPC Class Codes: C01B 2203/0405 Purification by membrane separation
• CPC Class Codes: C01B 2203/0415 Purification by absorption in liquids
• CPC Class Codes: C01B 2203/0445 Selective methanation
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 2203/068 Ammonia synthesis
• CPC Class Codes: C01B 2203/0811 by combustion of fuel
• CPC Class Codes: C01B 2203/0883 by indirect heat exchange
• CPC Class Codes: C01B 2203/1041 Composition of the catalyst
• CPC Class Codes: C01B 2203/1235 Hydrocarbons
• CPC Class Codes: C01B 2203/1288 Evaporation of one or more of the different feed components
• CPC Class Codes: C01B 2203/142 At least two reforming, decomposition or partial oxidation steps in series
• CPC Class Codes: C01B 2203/147 Three or more purification steps in series
• CPC Class Codes: C01B 2203/148 involving a recycle stream to the feed of the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 2203/84 : Energy production
• CPC Class Codes: C01B 3/025 : Preparation or purification of gas mixtures for ammonia synthesis
• CPC Class Codes: C01B 3/382 : Multi-step processes
• CPC Class Codes: C01B 3/384 : the catalyst being continuously externally heated
• CPC Class Codes: C01B 3/48 : followed by reaction of water vapour with carbon monoxide

Abstract

A method can include combusting an expanded turbine exhaust and a first fuel within a first reformer to produce a first exhaust. A hydrocarbon can be reformed in the first reformer to produce a reformed hydrocarbon and heat can be transferred from the first exhaust to a first medium. A refrigeration unit can be powered with thermal energy from the heated first medium and can cool a second medium. Heat can be transferred from one or more oxidants to the cooled second medium to produce cooled first and second oxidants. The cooled first oxidant and a second fuel can be introduced to a gas turbine unit to produce the expanded turbine exhaust and mechanical power. The cooled second oxidant can be compressed in a compressor powered with the mechanical power and the compressed second oxidant and the reformed hydrocarbon can be introduced to a second reformer to produce a syngas.

Claims

1. A method for reforming a hydrocarbon, comprising:

combusting at least a portion of an expanded turbine exhaust gas and a first fuel within a first reformer to produce a first reformer exhaust gas;

reforming a hydrocarbon in the first reformer in the presence of one or more first catalysts and steam at conditions sufficient to produce a first reformed hydrocarbon;

heating one or more first transfer mediums by indirectly transferring heat from the first reformer exhaust gas to the one or more first transfer mediums;

powering one or more refrigeration units with thermal energy from the one or more heated first transfer mediums;

cooling one or more second transfer mediums within the one or more refrigeration units to produce one or more cooled second transfer mediums;

transferring heat from one or more oxidants to the one or more cooled second transfer mediums to produce a cooled first oxidant and a cooled second oxidant;

introducing the cooled first oxidant and a second fuel to a gas turbine unit to produce the expanded turbine exhaust gas and mechanical power;

powering a compressor with the mechanical power;

compressing the cooled second oxidant in the compressor to produce a compressed second oxidant; and

introducing the compressed second oxidant and the first reformed hydrocarbon to a second reformer to produce a syngas product.

2. The method of claim 1, wherein the one or more first transfer mediums and the one or more second transfer mediums comprise water, steam, hot oil, or any combination thereof.

3. The method of claim 1, wherein the one or more heated first transfer mediums comprise at least three transfer mediums, wherein a first heated first transfer medium comprises steam at a pressure of about 375 kPa to about 1,100 kPa, a second heated first transfer medium comprises steam at a pressure of about 125 kPa to about 350 kPa, and a third heated first transfer medium comprises water at a temperature of about 80°

C. to about 100°

C.

4. The method of claim 3, further comprising:

introducing the first heated first transfer medium to a two stage lithium bromide absorption refrigeration unit to produce a first cooled second transfer medium;

introducing the second heated first transfer medium to a first single stage lithium bromide absorption refrigeration unit to produce a second cooled second transfer medium;

introducing the third heated first transfer medium to a second single stage lithium bromide absorption refrigeration unit to produce a third cooled second transfer medium; and

combining the first cooled second transfer medium, the second cooled second transfer medium, and the third cooled second transfer medium to produce a single cooled second transfer medium.

5. The method of claim 1, wherein the one or more refrigeration units comprise a single stage lithium bromide absorption refrigeration unit, a two stage lithium bromide absorption refrigeration unit, or a combination thereof.

6. The method of claim 1, wherein the one or more cooled second transfer mediums have a temperature ranging from about 1°

C. to about 20°

C.

7. The method of claim 1, wherein the cooled first oxidant has a temperature ranging from about 5°

C. and about 35°

C., and wherein the cooled second oxidant has a temperature ranging from about 5°

C. and about 20°

C.

8. The method of claim 7, further comprising varying the temperature of the first cooled oxidant to match a demand of the gas turbine unit.

9. The method of claim 1, wherein the first reformer comprises a steam methane reformer and the second reformer comprises an autothermal reformer.

10. The method of claim 1, further comprising transferring heat from the exhaust gas to the compressed second oxidant to produce a heated compressed oxidant having a temperature ranging from about 450°

C. to about 650°

C. and a pressure ranging from about 1,500 kPa to about 8,000 kPa.

11. The method of claim 1, wherein the exhaust gas exits the exhaust duct at a temperature of about 90°

C. to about 150°

C.

12. The method of claim 1, wherein the hydrocarbon has a steam-to-carbon molar ratio ranging from about 2.7 to about 4.

13. The method of claim 1, wherein the syngas product comprises about 10 mol % or less methane, about 40 mol % to about 60 mol % hydrogen, about 20 mol % to about 30 mol % nitrogen, about 5 mol % to about 15 mol % carbon monoxide, and about 10 mol % to about 20 mol % carbon dioxide, and the method further comprises converting at least a portion of the nitrogen and hydrogen in the syngas product to ammonia to produce an ammonia effluent.

14. A system for reforming a hydrocarbon, comprising:

a first reformer configured to produce a first reformed hydrocarbon and an exhaust gas;

one or more first heat exchangers at least partially disposed within an exhaust duct of the first reformer, wherein the exhaust gas transfers heat to one or more first transfer mediums flowing through the one or more first heat exchangers;

one or more refrigeration units coupled to the one or more first heat exchangers and configured to receive the one or more heated first transfer mediums, wherein the one or more heated first transfer mediums power the one or more refrigeration units, and wherein the one or more refrigeration units are configured to cool one or more second transfer mediums;

one or more second heat exchangers coupled to the one or more refrigeration units and configured to transfer heat from one or more oxidants to the one or more cooled second transfer mediums to produce a cooled first oxidant and a cooled second oxidant;

one or more gas turbine units configured to receive the cooled first oxidant, wherein the one or more gas turbine units produce mechanical power and an expanded turbine exhaust gas;

one or more compression units configured to receive the cooled second oxidant to produce a compressed second oxidant; and

a second reformer configured to receive the compressed second oxidant and the first reformed hydrocarbon and produce a syngas product therefrom.

15. The system of claim 14, further comprising a third heat exchanger disposed within the exhaust duct of the first reformer, wherein the exhaust gas transfers heat to the compressed second oxidant via the third heat exchanger to produce a heated second oxidant.

16. The system of claim 14, wherein the one or more refrigeration units comprise a single stage lithium bromide absorption refrigeration unit, a two stage lithium bromide absorption refrigeration unit, or a combination thereof.

17. The system of claim 14, wherein the one or more refrigeration units, comprise one two stage lithium bromide absorption refrigeration unit and two single stage lithium bromide absorption refrigeration units.

18. The system of claim 14, wherein the one or more second heat exchangers comprise a third heat exchanger adapted to transfer heat from a first portion of the cooled second transfer medium to produce the cooled first oxidant and a fourth heat exchanger adapted to transfer heat from a second portion of the cooled second transfer medium to produce the cooled second oxidant.

19. The system of claim 14, further comprising one or more ammonia synthesis systems configured to convert at least a portion of any hydrogen and nitrogen in the syngas product to ammonia.

20. The system of claim 19, wherein the one or more gas turbine units are frame-5 gas turbine units, and wherein the one or more ammonia synthesis systems produce between about 2,200 tons per day to about 2,500 tons per day.