System and method for cooling syngas produced from a gasifier

1. A syngas cooler comprising:

an outer wall defining a cavity;

an inner membrane water wall positioned within said cavity;

an outer membrane water wall substantially concentrically aligned with said inner membrane water wall, such that said outer membrane water wall is positioned between said inner membrane water wall and said outer wall;

at least one half pipe having a semicircular cross-section directly coupled to an inner surface of said outer membrane water wall; and

a thermal siphon positioned between said inner membrane water wall and said outer wall, said thermal siphon configured to channel a flow of syngas therethrough to facilitate cooling the channeled syngas.

2. A syngas cooler in accordance with claim 1 further comprising a middle membrane water wall substantially concentrically aligned with said outer membrane water wall, wherein said middle membrane water wall is positioned between said inner and said outer membrane water walls.

3. A syngas cooler in accordance with claim 2 further comprising a lockhopper coupled to said outer wall for collecting slag contained in the injected syngas.

4. A syngas cooler in accordance with claim 2 further comprising a first angled wall extending inward from said inner membrane water wall, and a second angled wall coupled to said first angled wall, said first angled wall and said second angled wall are configured to promote recirculation of the syngas.

5. A syngas cooler in accordance with claim 2 further comprising first radial wing walls coupled between said inner membrane water wall and said middle membrane water wall, and second radial wing walls coupled between said middle membrane water wall and said outer membrane water wall.

6. A syngas cooler in accordance with claim 2 further comprising a ramming mix refractory coating layer coupled to a top section of said inner membrane water wall.

7. A syngas cooler in accordance with claim 2 further comprising at least one entry coupled to at least one of said inner membrane water wall, said outer membrane water wall, and said middle membrane water wall for channeling a flow of cooling fluid therethrough.

8. A syngas cooler in accordance with claim 2 further comprising a quench wall coupled to said outer membrane water wall for channeling the syngas from the thermal siphon to a quench chamber, wherein said quench chamber facilitates rapidly cooling the syngas.

9. A syngas cooler in accordance with claim 1 , wherein said half pipe comprises a low alloy half pipe and a SiC coating.

10. A syngas cooler in accordance with claim 1 further comprising a gasifier positioned within a top portion of said inner membrane water wall and configured to channel hot syngas downward inside said inner membrane water wall.

11. A gas turbine engine system comprising:

a compressor;

a combustor in flow communication with said compressor to receive at least some of the air discharged by said compressor; and

a syngas cooler coupled in flow communication with said combustor for channeling a flow of syngas to said combustor, said syngas cooler comprising:

an outer wall defining a cavity;

a inner membrane water wall positioned within said cavity;

a outer membrane water wall substantially concentrically aligned with said inner membrane water wall, such that said outer membrane water wall is positioned between said inner membrane water wall and said outer wall;

at least one half pipe having a semicircular cross-section directly coupled to an inner surface of said outer membrane water wall; and

a thermal siphon positioned between said inner membrane water wall and said outer wall, said thermal siphon configured to channel the syngas therethrough to facilitate cooling the channeled syngas.

12. A gas turbine engine system in accordance with claim 11 , wherein said syngas cooler further comprises a middle membrane water wall substantially concentrically aligned with said outer membrane water wall, wherein said middle membrane water wall is positioned between said inner and said outer membrane water walls.

13. A gas turbine engine system in accordance with claim 12 , wherein said syngas cooler further comprises a quench wall coupled to said outer membrane water wall for channeling the syngas from the thermal siphon to a quench chamber, wherein said quench chamber facilitates rapidly cooling the syngas.

14. A gas turbine engine system in accordance with claim 11 , wherein said syngas cooler further comprises a gasifier positioned within a top portion of said inner membrane water wall and configured to channel hot syngas downward inside said inner membrane water wall.

15. A gas turbine engine system in accordance with claim 11 , further comprising a heat exchanger coupled between said syngas cooler and a syngas scrubber, wherein said syngas cooler channels a first flow of syngas to said heat exchanger, said syngas scrubber channels a second flow of syngas to said heat exchanger for transferring heat from said first flow of syngas to said second flow of syngas.

16. A method for cooling syngas produced in a gasifier and separating slag and particulate matter from the syngas, the method comprising:

surrounding a flow of syngas with three concentric, vertically oriented membrane water walls inside a syngas cooling unit;

channeling cooling fluid through the three concentric membrane water walls;

passing the syngas down through a first of the three membrane water walls to partially cool the syngas and separate slag and particulate matter from the syngas; and

utilizing a thermal siphon to pass the partially cooled syngas up between the first of the three membrane water walls and a second of the three membrane water walls and then down between the third of the three membrane water walls and the second of the three membrane water walls to produce cooled output syngas;

wherein at least one half pipe having a semicircular cross-section is directly coupled to an inner surface of said third membrane water wall.

17. A method in accordance with claim 16 further comprising using the cooled output syngas to generate electrical power.

18. A method in accordance with claim 17 wherein using the syngas to generate electrical power comprises burning the cooled output syngas to produce hot, high pressure gas.

19. A method in accordance with claim 18 wherein using the syngas to generate electrical power further comprises channeling the hot, high pressure gas and compressed air from a compressor over a turbine to power a first electrical generator.

20. A method in accordance with claim 19 further comprising operating a second generator using waste heat from the turbine.