Power plants – Combustion products used as motive fluid
Reexamination Certificate
2000-03-29
2001-09-11
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
C060S039182
Reexamination Certificate
active
06286297
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a combined cycle power generation plant, constructed by combining a gas turbine unit and a steam turbine unit, in which a stabilizing burner is incorporated in a waste heat recovery boiler thereof.
2. Description of the Prior Art
A combined cycle power generation plant is a power generation system constructed by combining a gas turbine unit and a steam turbine unit. A high temperature range of the power generation plant thermal energy is used by the gas turbine, and a low temperature range is used by the steam turbine. Thus, the thermal energy is recovered and used effectively, so that this type of power generation system has recently come to be widely used.
In such combined cycle power generation plant, it is an active tendency to employ a steam cooling method for cooling the gas turbine, steam turbine, etc. using a cooling medium comprised of steam generated in its own cycle. That is, according to this steam cooling method, a high temperature portion of the gas turbine, for example, is cooled by steam, and the thermal energy obtained thereby is recovered by a bottom cycle of the steam turbine. Consequently, a highly advantageous system having an enhanced thermal efficiency can be obtained.
However, in order to effect a restart of the plant after the plant has been stopped (such as for a plant start-up after completion of inspection work, a weekly start and stop (WSS) in which a start and stop of operation are done in weekly intervals, or a daily start and stop (DSS) in which a start and stop of operation are done in daily intervals), the steam for cooling must be obtained from outside of the plant's own cycle. For example, the plant must depend on the steam from an auxiliary boiler which is installed outside.
In order to obtain the steam, which is needed at the time the plant is restarted after the plant has been stopped, various additional facilities are needed. This results in a complex plant, increased cost, and troublesome operation. On the other hand, if dependence on the auxiliary boiler is avoided by only waiting for steam generation at the waste heat recovery boiler while the gas turbine is held in start-up and during speed increases, then an unfavorable situation occurs from the view point of resonance of the compressor and turbine blades.
SUMMARY OF THE INVENTION
In order to solve the problems in the prior art as mentioned above, it is an object of the present invention to provide a combined cycle power generation plant which is able to secure steam needed at the time a plant is restarted after the plant has been stopped (i.e., a start-up period of the operation of the plant). Moreover, it is an object to shorten the time for the plant to reach a full load from the start-up.
In order to attain these objects, it is a feature of the present invention to provide a combined cycle power generation plant constructed by combining a gas turbine unit and a steam turbine unit. The combined plant includes a waste heat recovery boiler for generating steam for driving the steam turbine by using waste heat from the gas turbine. In addition, a stabilizing burner is incorporated at an upstream position in the waste heat recovery boiler.
That is, the stabilizing burner, which is incorporated at the upstream position in the waste heat recovery boiler, is ignited during start-up and speed increases of the gas turbine so that generation of steam at the waste heat recovery boiler is accelerated. Thus, the steam is used effectively for cooling the gas turbine, driving the steam turbine and also as gland steam. In addition, exhaust steam from the high pressure steam turbine is also used to cool the gas turbine. Therefore, the time for the plant to reach a full load can be shortened.
It is another feature of the present invention to provide a combined cycle power generation plant as mentioned above, in which the stabilizing burner provided in the waste heat recovery boiler is constructed such that the stabilizing burner is supplied with fuel from a fuel supply source which is common to a combustor of the gas turbine.
It is also a feature of the present invention to provide a combined cycle power generation plant as first mentioned above, in which the stabilizing burner provided in the waste heat recovery boiler is constructed such that the stabilizing burner is supplied with fuel from a fuel supply source which is different from a fuel supply source of a combustor of the gas turbine.
REFERENCES:
patent: 3304712 (1967-02-01), Pacault et al.
patent: 3751866 (1973-08-01), Sokolowski
patent: 3930367 (1976-01-01), Gasparoli
patent: 4424668 (1984-01-01), Mukherjee
patent: 5577377 (1996-11-01), Tomlinson
patent: 5979156 (1999-11-01), Uematsu et al.
patent: 8-296410 (1996-11-01), None
Fukuizumi Yasushi
Wakazono Osamu
Casaregola Louis J.
Mitsubishi Heavy Industries Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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