Integration of molten carbonate fuel cells in iron and steel processing

Patent metadata

Field	Value
Publication number	US-9263755-B2
Application number	US-201414207726-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 15, 2013
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

In various aspects, systems and methods are provided for operating molten carbonate fuel cells with processes for iron and/or steel production. The systems and methods can provide process improvements such as increased efficiency, reduction of carbon emissions per ton of product produced, or simplified capture of the carbon emissions as an integrated part of the system. The number of separate processes and the complexity of the overall production system can be reduced while providing flexibility in fuel feed stock and the various chemical, heat, and electrical outputs needed to power the processes.

First claim

What is claimed is:

1. A method for producing iron and/or steel, the method comprising:
introducing a fuel stream comprising a reformable fuel into an anode of a molten carbonate fuel cell, an internal reforming element associated with the anode, or a combination thereof;
introducing a cathode inlet stream comprising CO 2 and O 2 into a cathode of the molten carbonate fuel cell;
generating electricity within the molten carbonate fuel cell;
withdrawing, from an anode exhaust, a first gas stream comprising CO, the anode exhaust having a pressure of about 500 kPag or less; and
introducing the first gas stream withdrawn from the anode exhaust into a process for production of iron and/or steel.

2. The method of claim 1 , further comprising using the electricity generated to provide heat to the process for production of iron and/or steel.

3. The method of claim 1 , further comprising withdrawing a second gas stream comprising H 2 from the anode exhaust, and using the second gas stream as fuel for heating the process for production of iron and/or steel.

4. The method of claim 1 , further comprising separating water from the anode exhaust, the first gas stream withdrawn from the anode exhaust, or a combination thereof, and washing a process slag using the separated water.

5. The method of claim 1 , wherein the cathode inlet stream comprises at least a portion of a CO 2 -containing exhaust generated by the process for production of iron and/or steel.

6. The method of claim 5 , further comprising separating CO 2 from the CO 2 -containing exhaust generated by the process for production of iron and/or steel.

7. The method of claim 1 , further comprising exposing the withdrawn first gas stream to a water gas shift catalyst under effective water gas shift conditions prior to introducing the withdrawn first gas stream into the process for production of iron and/or steel.

8. The method of claim 1 , wherein the molten carbonate fuel cell is operated to generate electricity at a thermal ratio of about 1.0 or less, the method further comprising transferring heat from the process for production of iron and/or steel to the molten carbonate fuel cell.

9. The method of claim 8 , wherein a temperature of the anode exhaust is greater than a temperature at an anode inlet.

10. The method of claim 8 , wherein transferring heat from the process for production of iron and/or steel comprises performing heat exchange between an anode inlet stream and at least one of an iron and/or steel production process furnace and an iron and/or steel production process exhaust.

11. The method of claim 10 , wherein performing the heat exchange comprises increasing a temperature of the anode inlet stream by at least about 100° C.

12. The method of claim 1 , wherein the molten carbonate fuel cell is operated at a thermal ratio from about 0.25 to about 1.0.

13. The method of claim 1 , further comprising separating at least one of CO 2 and H 2 O from at least one of the anode exhaust and the withdrawn gas stream in one or more separation stages.

14. The method of claim 1 , wherein an amount of the reformable fuel introduced into the anode, the internal reforming element associated with the anode, or the combination thereof, provides a reformable fuel surplus ratio of at least about 1.5.

15. The method of claim 1 , wherein a ratio of net moles of syngas in the anode exhaust to moles of CO 2 in a cathode exhaust is at least about 2.0.

16. The method of claim 1 , wherein a fuel utilization in the anode is about 50% or less and a CO 2 utilization in the cathode is at least about 60%.

17. The method of claim 1 , wherein the molten carbonate fuel cell is operated to generate electrical power at a current density of at least about 150 mA/cm 2 and at least about 40 mW/cm 2 of waste heat, the method further comprising performing an effective amount of an endothermic reaction to maintain a temperature differential between an anode inlet and an anode outlet of about 100° C. or less.

18. The method of claim 17 , wherein performing the endothermic reaction consumes at least about 40% of the waste heat.

19. The method of claim 1 , wherein an electrical efficiency for the molten carbonate fuel cell is between about 10% and about 40% and a total fuel cell efficiency for the molten carbonate fuel cell is at least about 55%.

20. The method of claim 1 , wherein at least about 90 vol % of the reformable fuel is methane.

Assignees

• Berlowitz Paul J
• Barckholtz Timothy Andrew
• Lee Anita S
• Exxonmobil Res & Eng Co

Inventors

• Berlowitz Paul J
• Barckholtz Timothy Andrew
• Lee Anita S

Classifications

• H01M8/04

  Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids · CPC title

• C01B3/34 Primary

  by reaction of hydrocarbons with gasifying agents · CPC title

• C01B2203/0205

  containing a reforming step · CPC title

• Y02P30/20

  using bio-feedstock · CPC title

• H01M8/0668

  Removal of carbon monoxide or carbon dioxide · CPC title