Power plants – Combustion products used as motive fluid – Combined with regulation of power output feature
Reexamination Certificate
1999-11-29
2001-09-25
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combined with regulation of power output feature
C060S039580, C060S039780
Reexamination Certificate
active
06293088
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to combustion turbine power plants and more particularly to fuel heating systems for combustion turbine power plants.
2. Background Information
It is known in the art to provide steam to preheat combustion fuel oil to vaporize the oil for use in combustion turbine systems. Typically an intermediate fluid, such as water, is heated until it becomes a gas, then the steam is mixed with the fuel oil, thereby heating and atomizing the fuel oil. The fuel heating steam may be provided by a separate steam boiler. Such a boiler adds a significant cost to the power plant. Alternatively, it is known in the art to indirectly utilize the exhaust gas from the combustion turbine to heat the steam. This type of system can be more costly due to the additional heat exchanger.
One prior art approach disclosed in U.S. Pat. No. 4,932,204 recovers heat available in the exhaust gas of the combustion turbine by increasing the water flow through the economizer section to a rate in excess of that required to match the steam production rate in the evaporator section. The excess water flow is withdrawn from the heat recovery steam generator at a temperature approaching the evaporator temperature and used to preheat the fuel delivered to the combust of the combustion turbine.
Another approach proposed to preheat fuel oil is to use waste heat from the combustion turbine rotor air cooler to raise the fuel temperature to above 600° F. (315° C.) One draw back to using the rotor air cooler waste energy is that it requires a complex arrangement and sophisticated controls to maintain relatively constant fuel temperature while simultaneously maintaining the required cooling for the rotor over the possible range of operating loads for the turbine.
Therefore, what is needed is a combustion turbine fuel oil heating system that is simple, economical, will allow the fuel oil to be heated above 600° F., if desired, and can be used in a simple or combined cycle combustion turbine power plant.
SUMMARY OF THE INVENTION
These needs and others are satisfied by the invention which is directed to a combustion turbine system which includes a manifold coupled with the steam cooling system of the combustion turbine. Steam passes through the combustion turbine, cooling the combustion turbine and absorbing heat. After passing through the combustion turbine the steam enters a outlet manifold where its flow can be controlled and directed concurrently or alternately to a nozzle placed at the combustion turbine compressor discharge cavity for power augmentation and/or it can be directed to the fuel oil nozzles thereby heating and atomizing the fuel oil and increasing the efficiency of the thermal cycle. By utilizing the cooling steam from the combustion turbine it is possible to eliminate the multimillion dollar cost of a separate steam boiler to provide steam to the fuel manifold.
Additionally, this invention can be incorporated into a combustion turbine using two alternative fuel sources; natural gas and oil. A fuel manifold is coupled to a natural gas source and the steam outlet manifold. The fuel manifold is further coupled to a fuel nozzle. The fuel nozzle includes a mixing chamber which is coupled with a fuel oil source. In operation, the combustion turbine can use either natural gas or fuel oil. When natural gas is used, the natural gas is introduced into the fuel manifold, passes through the mixing chamber and is injected by the nozzles into the combustor. When fuel oil is used, steam is introduced into the fuel manifold and fuel oil is introduced into the mixing chamber, when the steam passes into the mixing chamber the fuel oil is vaporized prior to being injected by the nozzles into the combustor.
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Moore Jack D.
Steinebronn Brad A.
Casaregola Louis J.
Siemens Westinghouse Power Corporation
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