Power plants – Combustion products used as motive fluid – Combined with regulation of power output feature
Reexamination Certificate
2002-09-17
2003-05-27
Freay, Charles G. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combined with regulation of power output feature
C060S039530
Reexamination Certificate
active
06568168
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a gas turbine and more particularly, to a gas turbine which injects water droplets into an intake air of a compressor of the gas turbine.
A conventional gas turbine is caused to drop its output in a summer season when the temperature increases, therefore, various arrangements have been proposed as a method to recover the dropped output.
JP-A Laid-Open No. 7-97933, JU No.61-37794, or JP-A Laid-Open No. 5-195809 disclose that the intake air of the compressor is cooled.
Further, JP-A Laid-Open No. 61-283723 discloses that water is supplied from the inlet of the compressor and from the intermediate stage of the compressor in a combined system of a gassification furnace and a gas turbine.
Further, JU-A No. 56-43433 discloses that a supply port through which to supply water droplets is provided in its compressor, and JP-A No. 2-211331 discloses a gas turbine which is provided with two types of compressors of a high pressure and a low pressure, and an intermediate cooler which is provided between these two types of compressors. Still further, JP-A No.6-10702 discloses a technique to inject water into an intermediate section between an upper-stream compressor stage and a down-stream compressor stage in a compressor group having a plurality of compressor stages in order to reduce power consumption.
However, what are disclosed by these related arts of JP-A No. 7-97933, JU No.61-37794 or JP-A No. 5-195809 are addressed simply to dropping temperatures of intake air to be admitted into the compressor so as to be able to improve its output. JP-A No.61-283723 merely discloses vaporization of water droplets in the compressor and utilization thereof as a medium to cool the turbine blades, and as a consequence, improvement of turbine cycle characteristics.
Further, JP-A No.2-211331 discloses the gas turbine which is provided with an intermediate cooler which is provided between the two types of compressors of high pressure and low pressure, and wherein means for detecting a temperature and a humidity at the inlet of the high pressure compressor are provided, and a feed water flow to the intermediate cooler is controlled. However, this control does not teach nor suggest water injection into the compressor itself, and is not concerned with control of humidity at the inlet of the compressor.
In consideration of an actual operation of a gas turbine or a combined cycle using a gas turbine and a steam turbine, there is required a development of a system which can realize a safety operation of the gas turbine while always ensuring protection of the gas turbine itself, and which can improve its output and thermal efficiency using a simple arrangement.
SUMMARY OF THE INVENTION
An object of the invention is to provide a gas turbine which can realize improvements both on its output and thermal efficiency through injection of liquid droplets into intake air introduced to the inlet of the compressor using simple facilities suitable for actual application, and also a safety operating system using the same.
A first present invention is a gas turbine having a compressor for compressing an air supplied therein and discharging a compressed air, a combustor for combusting the compressed gas from the compressor and a fuel and a gas turbine to be driven by a combustion gas from the combustor, characterized by comprising an injection unit, arranged at an upstream side of the compressor and constructed so that water droplets are sprayed into the air to be supplied to the compressor to lower the temperature of the air to be supplied into the compressor to a temperature lower than an atmospheric temperature and the sprayed water droplets introduced into the compressor with the air having been lowered in temperature are evaporated during passage through the compressor, a detection unit for detecting the humidity of air to be supplied to the compressor, and a controlling unit for controlling a quantity of water droplets to be sprayed from the injection unit on the basis of a signal from the detection unit.
For example, it is possible to control a spray quantity of the liquid droplets according to the detected signal.
The humidity of intake air at the upstream side of the injection unit, for example, is detected and a spray quantity of the liquid droplets is controlled to be more when the humidity is low than when it is high.
Further, it is preferable for the control unit to have a detection unit for detecting the temperature and humidity of air supplied to the compressor and control a spray quantity of water droplets sprayed from the injection unit on the basis of the detection signal. By detecting the temperature of air at the upstream side of the injection unit, the spray quantity of water droplets is controlled to be more at a lower temperature than at a higher temperature, and the spray quantity of water droplets is controlled to be more when the humidity of air at the upstream side of the injection unit is lower than when the humidity is higher than when low.
Further, it is possible to control the above-mentioned spray quantity on the basis of output, etc. and use it as a limit value of the spray quantity on the basis of the above-mentioned detection signal. The control unit has a limit value set for a spray quantity of water droplets from the injection unit on the basis of the detection signal and controls the spray quantity to be within the above-mentioned limit value.
For example, a spray quantity of water droplets is determined according to output. In this case, the temperature of intake air at the upstream side of the injection unit is detected, the above-mentioned limit value is made higher when the temperature is lower than when high, the above-mentioned limit value is made higher when the humidity of intake air at the upstream of the injection unit is lower than when high, and a spray quantity of the water droplets is controlled (corrected) not to exceed the limit value.
Thereby, the soundness of the compressor is secured and a high output operation of the gas turbine can be executed. Since a water spray quantity is adjusted by considering the humidity of intake air when water droplets are injected into the intake air, a quantity of water droplets introduced into the compressor without evaporating until the injected water droplets reach the compressor inlet can be controlled to be a proper quantity, and a quantity of water droplets having been evaporated until they reach the compressor inlet and a quantity of water droplets having been evaporated within the compressor can be suitably controlled. Therefore, the gas turbine can be operated at a high output while securing the soundness of the plant, taking into consideration an influence on the compressor.
Thereby, it is possible to practice water injection while securing a safety operation of the gas turbine main body.
For example, when detecting means for detecting the temperature and humidity of gas at the upstream side of the compressor is provided, a water spray quantity limit value related to the temperature and humidity is set and the water quantity is controlled so that a real effective water spray quantity does not exceed the above-mentioned water spray quantity limit value during a water spraying operation, such cases can be considered that the effective water spray quantity is calculated from the humidity of gas at the compressor discharge portion and the humidity of gas at the upstream side of the injection unit and that it is calculated from a water quantity indication value of the water supply system and a drain occurrence amount in the intake air duct of the upstream side of the compressor. However, any case can be taken. The humidity of compressor discharge air can be measured by continuously drafting air into a tank for sampling which is provided with a humidity detecting means.
A second invention is a gas turbine, having a compressor for compressing an air supplied therein and discharging a compressed air, a combustor for combusting the compressed gas from the compressor and a fuel
Hirose Fumiyuki
Horii Nobuyuki
Katoh Yasuhiro
Kuwahara Takaaki
Murata Hidetaro
Freay Charles G.
Mattingly Stanger & Malur, P.C.
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