Westinghouse Electric Corporation

The United States of America as Represented by the United States

Siemens Westinghouse Power Corporation

Thomas E Dowdy

Ronald L Bannister

Janos M Beer

JoAnn M Linder

Wayne L Lundberg

William F Domeracki

Donald L Bonk

Darren J Mollot

A system and method generates electricity and co-produces a hydrogen flow from coal. The electricity is generated by a turbine with a topping combustor and a solid oxide fuel cell ('SOFC') reacting syngas. The syngas is produced in a coal gasifier with a portion of the compressed air from the turbine, coal, and steam. Prior to the syngas being delivered to the topping combustor and the SOFC, it is cleaned and a portion of the hydrogen in the syngas is removed to form the hydrogen flow. Additionally, a vitiated air flow from the SOFC is directed to the topping combustor and another portion of the compressed air from the turbine directed to the SOFC after it is heated with the turbine exhaust. An aspect of the invention varies the amount of electricity generated and the volume of hydrogen co-produced based upon the demand of electricity and/or the demand of said hydrogen.

Coal gasification and hydrogen production system and method

Hydrogen is used as the fuel source in a gas turbine combined cycle power plant. The hydrogen may be combusted in either a mixture of compressed air and steam or a mixture of pure oxygen and steam. In either case, the work of compression associated with pressurizing the oxidant for the combustion process is considerably reduced since steam, rather than excess air, is used to moderate combustion temperature, as well as to cool the turbine components. The steam is produced by transferring heat from the turbine exhaust gas to feed water. Since no hydrocarbon fuel is used, fuel bound NOx is eliminated. Moreover, if pure oxygen is used, rather than air, for the combustion of the hydrogen, then the only emission from the power plant is water vapor, which may be condensed and returned to the cycle.

High efficiency method to burn oxygen and hydrogen in a combined cycle

Polluting NO.sub.x gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO.sub.x gases are removed is directed to introducing NO.sub.x -free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor.

Removal of oxides of nitrogen from gases in multi-stage coal combustion

A combustor for burning a mixture of fuel and air in a rich combustion zone, in which the fuel bound nitrogen in converted to molecular nitrogen. The fuel rich combustion is followed by lean combustion. The products of combustion from the lean combustion are rapidly quenched so as to convert the fuel bound nitrogen to molecular nitrogen without forming NOx. The combustor has an air radial swirler that directs the air radially inward while swirling it in the circumferential direction and a radial fuel swirler that directs the fuel radially outward while swirling it in the same circumferential direction, thereby promoting vigorous mixing of the fuel and air. The air inlet has a variable flow area that is responsive to variations in the heating value of the fuel, which may be a coal-derived fuel gas. A diverging passage in the combustor in front of a bluff body causes the fuel/air mixture to recirculate with the rich combustion zone.

Gas turbine topping combustor

A gas turbine power plant having a pressurized fluidized bed combustor and an external topping combustor. A cylindrical duct and a toroidal duct direct the flow of hot gas from the topping combustor and distribute it around the circumference of the turbine inlet. The walls of the duct are cooled by water or steam. The walls are formed by tubes, having cooling fluid passages formed therein, that extend between inlet and outlet manifolds. Elongated plate sections connect each tube to an adjacent tube so as to form a continuous gas barrier. If the walls are water cooled, the water that flows through the tubes for cooling is subsequently directed to a heat recovery steam generator, in which it is converted to steam for expansion in a steam turbine. If the walls are steam cooled, the steam is first generated in the heat recovery steam generator and then at least partially superheated by flowing through the walls.

Ducting for an external gas turbine topping combustor

An improved integrated gas turbine solid oxide fuel cell system. The system has a compressor for producing compressed air that is pre-heated and then supplied to a solid oxide fuel cell generator. The solid oxide fuel cell generator, which is also supplied with a first stream of fuel, produces electrical power and a hot gas. In the solid oxide fuel cell generator, the unreacted portion of the fuel is combusted with the oxygen remaining in the hot gas to further heat the hot gas. The further heated hot gas is then directed to a topping combustor that is supplied with a second stream of fuel so as to produce a still further heated hot gas that is then expanded in a turbine.

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Orlando, FL, United States of America

Thomas E Dowdy