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There is provided a low-emission, staged-combustion power generation system and associated method for generating power. The power generation system and method combust a carbonaceous fuel with an oxidizing fluid, both of which are substantially free of nitrogen and sulfur, to generate power, for exam

There is provided a low-emission, staged-combustion power generation system and associated method for generating power. The power generation system and method combust a carbonaceous fuel with an oxidizing fluid, both of which are substantially free of nitrogen and sulfur, to generate power, for example, in the form of electricity, without the formation of nitrous oxides (NOx) and sulfur oxides (SOx). Efficiency is enhanced using a multi-staged combustion, in which the carbonaceous fuel is partially combusted before passing through a first power take-off device and subsequently reheated and passed through one or more additional power take-off devices. Additionally, exhaust gases from one or more of the power take-off devices can be extracted and processed to provide quantities of useful products such as hydrogen and methanol.

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1. A method of generating power, comprising:supplying a carbonaceous fuel substantially free of nitrogen and sulfur to a gas generator;supplying a first oxidizing fluid substantially free of nitrogen and sulfur to the gas generator at a sub-stoichiometric rate relative to the carbonaceous fuel;combu

1. A method of generating power, comprising:supplying a carbonaceous fuel substantially free of nitrogen and sulfur to a gas generator;supplying a first oxidizing fluid substantially free of nitrogen and sulfur to the gas generator at a sub-stoichiometric rate relative to the carbonaceous fuel;combusting the carbonaceous fuel with the first oxidizing fluid in the gas generator to produce a combusted gas;discharging the combusted gas to a first power take-off device;discharging at least a portion of the combusted gas from the first power take-off device to a reheater;combusting the combusted gas with a second oxidizing fluid substantially free of nitrogen and sulfur in the reheater to form a reheated gas; anddischarging the reheated gas to a second power take-off device. 2. A method of generating power according to claim 1, further comprising providing at least one of the first and second oxidizing fluids by separating oxygen from air. 3. A method of generating power according to claim 1, wherein the step of supplying the carbonaceous fuel to the gas generator comprises supplying methane. 4. A method of generating power according to claim 1, wherein said step of supplying the first oxidizing fluid to the gas generator at a sub-stoichiometric rate comprises supplying the first oxidizing fluid to the gas generator at a sub-stoichiometric rate of between 0 and 50 percent relative to the carbonaceous fuel. 5. A method of generating power according to claim 1, further comprising regulating a supply of the second oxidizing fluid to the reheater to be sub-stoichiometric relative to combustible materials in the combusted gas. 6. A method of generating power according to claim 1, wherein said step of combusting the carbonaceous fuel with the first oxidizing fluid in the gas generator comprises at least partially combusting at least 98 percent of the carbonaceous fuel. 7. A method of generating power according to claim 1, wherein said steps of discharging the combusted gas to a first power take-off device comprises discharging the combusted gas to a first turbine coupled to at least one electric generator, and discharging the reheated gas to a second power take-off device comprises discharging the reheated gas to a second turbine coupled to the at least one electric generator, and further comprising rotating the at least one electric generator to generate electricity. 8. A method of generating power according to claim 1, wherein said step of combusting the combusted gas with a second oxidizing fluid in the reheater comprises heating the combusted gas to at least 2000° F. 9. A method of generating power according to claim 1, wherein said step of combusting the combusted gas with a second oxidizing fluid in the reheater comprises producing a reheated gas comprising steam, carbon dioxide, between about 3 and 10 percent hydrogen by volume, between about 1 and 3 percent carbon monoxide by volume, and substantially free of nitrogen and sulfur. 10. A method of generating power according to claim 1, further comprising:subsequent to said step of discharging the reheated gas to the second power take-off device, discharging the reheated gas to a catalytic shift reactor to convert the carbon monoxide to hydrogen and carbon dioxide. 11. A method of generating power according to claim 1, further comprising:subsequent to said step of discharging the reheated gas to the second power take-off device, passing the reheated gas through at least one condenser and at least one compressor to remove water from the gas. 12. A method of generating power according to claim 1, further comprising:subsequent to said step of discharging the reheated gas to the second power take-off device, discharging the reheated gas to a separator to separate carbon dioxide from the reheated gas. 13. A method of generating power according to claim 1, further comprising:subsequent to said step of discharging the reheated gas to the second power take-off device, passing the rehe ated gas through a carbon monoxide catalytic converter to convert the reheated gas to methanol and hydrogen. 14. A method of generating power according to claim 1, further comprising discharging a variable portion of the combusted gas from the first power take-off device to a catalytic shift reactor to convert carbon monoxide in the variable portion of the combusted gas to hydrogen and carbon dioxide. 15. A method of generating power according to claim 14, further comprising discharging the variable portion of the combusted gas from the catalytic shift reactor to a separator to separate carbon dioxide from the combusted gas. 16. A method of generating power according to claim 1, further comprising discharging a variable portion of the reheated gas from the second power take-off device to a low pressure reheater, combusting the variable portion of the reheated gas to form a twice reheated gas, and discharging the twice reheated gas to a third power take-off device. 17. A method of generating power, comprising:generating an oxidizing fluid substantially free of nitrogen and sulfur;supplying a carbonaceous fuel substantially free of nitrogen and sulfur to a gas generator;supplying the oxidizing fluid to the gas generator at a sub-stoichiometric rate relative to the carbonaceous fuel;combusting the carbonaceous fuel with the oxidizing fluid in the gas generator to produce a combusted gas;discharging the combusted gas to a first power take-off device;discharging a first variable portion of the combusted gas to a first catalytic shift reactor;discharging a second variable portion of the combusted gas to a first reheater operating at a lower pressure than the gas generator;combusting the second variable portion of the combusted gas with the oxidizing fluid in the first reheater to form a reheated gas;discharging the reheated gas to a second power take-off device;discharging a first variable portion of the reheated gas to a second catalytic shift reactor operating at a lower pressure than the first catalytic shift reactor;discharging a second variable portion of the reheated gas to a second reheater operating at a lower pressure than the first reheater;combusting the second variable portion of the reheated gas with the oxidizing fluid in the second reheater to form a twice reheated gas;discharging the twice reheated gas to a third power take-off device;discharging the twice reheated gas to a third catalytic shift reactor operating at a lower pressure than the second catalytic shift reactor; andseparating the carbon dioxide, hydrogen, and water from the first variable portion of the combusted gas, the first variable portion of the reheated gas, and the twice reheated gas. 18. A method of generating power according to claim 17, wherein said step of supplying the oxidizing fluid to the gas generator comprises supplying the oxidizing fluid to the gas generator at a sub-stoichiometric rate of between 0 and 50 percent relative to the carbonaceous fuel. 19. A method of generating power according to claim 17, further comprising:regulating a supply of the oxidizing fluid to the first reheater to a sub-stoichiometric rate higher than the sub-stoichiometric rate of the oxidizing fluid in the gas generator; andregulating a supply of the oxidizing fluid to the second reheater to a sub-stoichiometric rate higher than the sub-stoichiometric rate of the oxidizing fluid in the first reheater. 20. A method of generating power according to claim 17, wherein said step of combusting the carbonaceous fuel with the oxidizing fluid comprises at least partially combusting at least 98 percent of the carbonaceous fuel. 21. A method of generating power according to claim 17, wherein said steps of discharging the combusted gas to a first power take-off device comprises discharging the combusted gas to a first turbine coupled to at least one electric generator, and discharging the reheated gas to a second power take-off device comprises discharging the reheated ga s to a second turbine coupled to the at least one electric generator, and further comprising rotating the at least one electric generator to generate electricity. 22. A method of generating power according to claim 17, further comprising discharging at least part of the first variable portion of the combusted gas, the first variable portion of the reheated gas, and the twice reheated gas to a carbon monoxide catalytic reactor to convert carbon monoxide in the gases to methanol and hydrogen. 23. A power generation system, comprising:a gas generator configured to receive a carbonaceous fuel substantially free of nitrogen and sulfur and an oxidizing fluid substantially free of nitrogen and sulfur and combust the carbonaceous fuel with the oxidizing fluid to produce a combusted gas;a regulation system configured to regulate the flow of the oxidizing fluid into the gas generator at a sub-stoichiometric rate relative to the carbonaceous fuel;a first power take-off device configured to receive the combusted gas from the gas generator;a reheater configured to receive and combust the combusted gas from the first power take-off device and the oxidizing fluid to form a reheated gas; anda second power take-off device configured to receive the reheated gas from the reheater. 24. A power generation system according to claim 23, further comprising a source of the carbonaceous fuel substantially free of nitrogen and sulfur and a source of the oxidizing fluid substantially free of nitrogen and sulfur, wherein the source of the carbonaceous fuel is configured to supply the carbonaceous fuel to the gas generator and the source of the oxidizing fluid is configured to supply the oxidizing fluid to the gas generator and the reheater. 25. A power generation system according to claim 23, further comprising at least one generator coupled to the first and second power take-off devices. 26. A power generation system according to claim 23, further comprising an air separation plant for producing the oxidizing fluid from air. 27. A power generation system according to claim 23, wherein the carbonaceous fuel is methane. 28. A power generation system according to claim 23, wherein the gas generator is capable of at least partially combusting at least about 98 percent of the carbonaceous fuel. 29. A power generation system according to claim 23, wherein the first and second power take-off devices are turbines. 30. A power generation system according to claim 23, further comprising a regulation system configured to regulate the flow of the oxidizing fluid into the reheater at a stoichiometric rate relative to the carbonaceous fuel. 31. A power generation system according to claim 23, wherein the reheater is capable of heating the combusted gas to at least 2000° F. 32. A power generation system according to claim 23, wherein the reheated gas comprises carbon dioxide, between about 3 and 10 percent hydrogen by volume, between about 1 and 3 percent carbon monoxide by volume, and substantially free of nitrogen and sulfur. 33. A power generation system according to claim 23, wherein the reheater comprises a partial catalytic bed to facilitate the reaction of hydrogen in the combusted gas with oxygen. 34. A power generation system according to claim 23, further comprising:a catalytic shift reactor configured to receive the reheated gas from the second power take-off device. 35. A power generation system according to claim 23, further comprising:at least one condenser and at least one compressor configured to receive the reheated gas from the second power take-off device. 36. A power generation system according to claim 23, further comprising:a separator configured to receive the reheated gas from the second power take-off device and capable of separating carbon dioxide from the reheated gas. 37. A power generation system according to claim 36, wherein the separator is configured to receive cryogenic nitrogen from the air separation plant. 38. A power generatio n system according to claim 23, further comprising a carbon monoxide catalytic converter configured to receive the reheated gas from the second power take-off device. 39. A power generation system according to claim 23, further comprising:a catalytic shift reactor configured to receive a variable portion of the combusted gas from the first power take-off device, and wherein the catalytic shift reactor is capable of converting the variable portion of the combusted gas to hydrogen and carbon dioxide. 40. A power generation system according to claim 39, further comprising:a separator configured to receive the variable portion of the combusted gas from the catalytic shift reactor and capable of separating carbon dioxide from the variable portion of the combusted gas. 41. A power generation system according to claim 23, further comprising:a low pressure reheater configured to receive and combust a variable portion of the reheated gas from the second power take-off device to form a twice reheated gas and discharge the twice reheated gas to a third power take-off device. 42. A power generation system, comprising:a gas generator configured to receive a carbonaceous fuel substantially free of nitrogen and sulfur, receive an oxidizing fluid substantially free of nitrogen and sulfur, and combust the carbonaceous fuel with the oxidizing fluid to produce a combusted gas;a regulation system configured to regulate the flow of the oxidizing fluid into the gas generator at a stoichiometric rate relative to the carbonaceous fuel;a first power take-off device configured to receive the combusted gas from the gas generator;a first catalytic shift reactor configured to receive a first variable portion of the combusted gas from the first power take-off device;a first reheater configured to receive and combust a second variable portion of the combusted gas from the first power take-off device with the oxidizing fluid to form a reheated gas;a second power take-off device configured to receive the reheated gas from the first reheater;a second catalytic shift reactor configured to receive a first variable portion of the reheated gas from the second power take-off device;a second reheater configured to receive and combust a second variable portion of the reheated gas from the second power take-off device with the oxidizing fluid to form a twice reheated gas;a third power take-off device configured to receive the twice reheated gas from the second reheater;a third catalytic shift reactor configured to receive the twice reheated gas from the third power take-off device; andat least one separator, configured to receive the first variable portion of the combusted gas, the first variable portion of the reheated gas, and the twice reheated gas and capable of separating carbon dioxide, hydrogen, and water from the combusted gas, the first variable portion of the reheated gas, and the twice reheated gas. 43. A power generation system according to claim 42, further comprising a source of the carbonaceous fuel substantially free of nitrogen and sulfur and a source of the oxidizing fluid substantially free of nitrogen and sulfur, wherein the source of the carbonaceous fuel is configured to supply the carbonaceous fuel to the gas generator and the source of the oxidizing fluid is configured to supply the oxidizing fluid to the gas generator, the first reheater, and the second reheater. 44. A power generation system according to claim 42, further comprising at least one generator coupled to the first, second, and third power take-off devices.