Power plants – Combustion products used as motive fluid – Combined with regulation of power output feature
Reexamination Certificate
1999-07-16
2001-06-26
Thorpe, Timothy S. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combined with regulation of power output feature
Reexamination Certificate
active
06250068
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas turbine installation for driving a gas turbine for generating electric power, and in particular, to a gas tubine installation adapted to be built in a district in which snowfall can highly be expected.
2. Related Art
In general, there has been known a snow protection method for an intake-air filter in a ventilating and air-conditioning system, in which a snowbreak hood and a louver are mounted to a fresh air inlet of the ventilating and air-conditioning system. In this method, the snowbreak hood can substantially prevent entrance of snow in a normal snowfall condition, and the louver can prevent advance of snow into an intake-air passage by adjusting the opening degree of the louver in such a case that the amount of snowfall is huge or that the advance of snow cannot be fully prevented due to strong wind, in order to prevent the intake filter from clogging with snow.
For example, Japanese Laid-Open Patent No. H8-297188 discloses a snow protection system for a ventilating and air-conditioning system in a nuclear power plant, in which a heating coil is provided downstream of a louver, and a bird net incorporated with a snow-melting heater is provided between the lower end of a snowbreak hood and the lower end of the louver so as to melt snow which has entered since it cannot be melted by the snow melting heater and blocked by the louver, by means of the heating coil in order to prevent the intake-air filter from clogging.
In addition, Japanese Laid-Open Patent No. S61-211647, Japanese Laid-Open No. S61-295448, Japanese Laid-Open Patent No. S61-295449, Japanese Laid-Open Patent No. S62-102044, Japanese Laid-Open Patent No. S62-108939 and Japanese Laid-Open Patent No. H7-209469 also disclose snow protection technology relating ventilation facilities for power plants.
For example, Japanese Laid-Open Patent No. H6-33795 discloses an intake system for a gas turbine, in which bleed air from a low pressure stage of a compressor in the gas turbine is heated along the outer wall surface of the casing of the compressor, and is thereafter injected into the intake-air filter for the gas turbine in order to prevent freezing of the intake-air filter.
Further, Japanese Laid-Open Patent No. H9-317496 discloses an arrangement in which a heat-exchanger is provided in an intake duct of a gas turbine so as to carry out heat-exchange between intake-air into the gas turbine and heating medium in order to heat the intake air in the gas turbine, or to mix the intake-air in the gas turbine with high temperature fluid in order to heat the intake-air into the gas turbine.
Since a predetermined volume of air has to be continuously taken into a gas turbine during operation thereof, the volume of air cannot be reduced by closing a louver even though it is temporary.
Further, gas turbines have such a tendency as the higher the temperature of intake-air, the higher the drive power of a compressor, resulting in lowering of the efficiency of power generation and the output power thereof. In such a method that a heating coil or a heat-exchanger is provided, or high temperature fluid is mixed so as to raise the temperature of a gas turbine in order to melt snow contained in the intake-air, as disclosed in the above-mentioned Japanese Laid-Open Patent No. H8-297188 or Japanese Laid-Open Patent No. H9-317496, there has been offered a problem of lowering the efficiency of power generation and the output power thereof. Further, the operation of a gas turbine requires a large volume of air in comparison with a ventilating and air-conditioning system in a building (for example, a nuclear power plant station), and accordingly, a relatively large heating volume is required for uniformly raising the temperature of this large volume of intake-air required for the operation of the gas turbine, and for sufficiently melting snow contained in the intake-air until the intake-air reaches the inlet of an intake-air filter. Further, should a heating coil or a heat-exchanger is incorporated in an intake-duct, the pressure loss of a gas turbine becomes extremely high, and accordingly, there has been raised a problem of lowering the efficiency of air-intake.
Further, as disclosed in Japanese Laid-Open Patent No. H6-33795, a method in which high temperature air is directly injected into an intake-air filter in order to remove snow stuck to the filter, has offered a problem in heat-resistance, pressure resistance or the like, and further, exhibits a problem of lowering the compression efficiency since bleed air is extracted from a compressor.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a gas turbine installation in which the shape of a passage in an intake-air duct communicated with the suction side of an intake filter is regulated so as to heap up or stick snow in the intake-air duct, and accordingly, the volume of snow reaching the intake-air filer is reduced in order to prevent the intake filter from clogging, thereby it is possible to prevent the flow rate of intake-air in the gas turbine from being lowered.
To the end, according to the present invention, there is provided a gas turbine installation comprising a gas turbine, a first intake-air duct laid below the gas turbine, for feeding intake-air into the gas turbine, an exhaust duct laid above that intake-air duct, for discharging exhaust gas from the gas turbine, the first intake-air duct having an intake port laid below the exhaust duct and provided therein an intake-air filter, a second intake-air duct communicated with the upstream side of the first intake-air duct and having a second intake-air port formed in the upper part thereof, for introducing fresh air, a first passage extending in a substantially vertical direction from the second intake-air port to the exhaust duct, and a second passage communicated at its one end with the first passage, and extending from the communication part thereof in a substantially horizontal direction, and a third passage communicated at its one end with the second passage, extending from the communication part thereof in a substantially vertical direction, and communicated with the suction side of the intake-air filter provided in the first intake-air duct.
Further, preferably, the second intake-air duct is provided thereto with a snowbreak hood mounted to the second intake-air port and having a fresh-air intake port.
Further, preferably, a stagnating means for stagnating the flow of intake-air into the gas turbine, or a staying means for staying the flow of the intake air into the gas turbine is provided in the vicinity of the communication part between the first flow first passage and the second flow passage.
Further, preferably, a snow or ice melting means for melting snow or ice is provided in the vicinity of the communication part between the first passage and the second passage.
Further, preferably, a heating means for heating the wall surface of the second intake-air duct is provided in the second flow passage.
Further, a fresh air introducing means for introducing fresh air and for leading the same into the intake-air filter is provided in the third flow passage.
Further, preferably, the cross-sectional area of the second passage is set to be greater than that of the first passage through the entire length of the second passage or through the intermediate part thereof.
The present invention will be detailed in the form of preferred embodiments with reference to the accompanying drawings in which:
REFERENCES:
patent: 3796854 (1974-03-01), Bennett et al.
patent: 3834126 (1974-09-01), Diminno, Jr.
patent: 4509962 (1985-04-01), Breitman et al.
patent: 4561245 (1985-12-01), Ball
patent: 4860534 (1989-08-01), Easley
patent: 5979507 (1999-11-01), Kojima et al.
patent: 61-211647 (1986-09-01), None
patent: 61-295448 (1986-09-01), None
patent: 61-295449 (1986-12-01), None
patent: 62-108939 (1987-05-01), None
patent: 62-102044 (1987-05-01), None
patent: 6-33795 (1994-02-01), None
patent: 7-209469 (1995-08-01), None
pate
Higuma Katsutoshi
Tajima Katsuhiko
Tateishi Akitaka
Hitachi , Ltd.
Mattingly, Stanger & Malur
Rodriguez W
Thorpe Timothy S.
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