JPH06146924A - Gas turbine - Google Patents

Abstract

PURPOSE:To use an energy which has been thrown away outside a system through a cooling medium in order to increase the temperature of fuel, and store the energy in the system so as to improve the gas turbine efficiency and plant efficient by utilizing heat fetched from air for cooling a turbine by means of a fuel gas heater in order to heat fuel of a gas turbine. CONSTITUTION:A part of compressed air in the outlet of a compressor 2 is cooled by fuel supplied to a combustor 4, and the rotor of a turbine 3 and the like are cooled by cooled compressed air. Namely, air whose pressure and temperature are raised by the compressor 2 is not cooled by the cooling medium of water or atmosphere, but its air is cooled by fuel of as gas turbine 1 whose temperature is nearly equal to the atmosphere temperature. Air is cooled by a fuel, and fuel itself is heated, and also fuel is formed in such fuel whose energy level is higher by a level difference equivalent to sensible heat. It is thus possible to store the energy which has been thrown away outside the system, in the system by heat-exchanging with fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine having a cooler for cooling turbine air.

[0002]

2. Description of the Related Art FIG. 2 is a system diagram showing an example of a conventional gas turbine having a conventional cooling air cooler using external air or water as a cooling medium. The gas turbine (1) is mainly composed of a compressor (2) and a turbine (3), and air compressed by the compressor (2) is used as a working fluid.
After injecting fuel into the combustor (4) to produce high temperature combustion gas,
It is expanded in the turbine (3) and then released into the atmosphere. The velocity energy that accompanies the expansion of the combustion gas is converted into rotational energy via the moving / static vanes of the turbine (3). The temperature of the combustion gas reaches a temperature range of several thousand and several hundred degrees with the recent increase in temperature, and therefore, in order to maintain the reliability of the material, it is necessary to perform cooling with low temperature air. Therefore, a part of the air at the outlet of the compressor (2) is guided to the outside of the gas turbine, cooled by a cooling air cooler (5) with a cooling medium such as water, and then cooled to a high temperature part such as a rotor of the turbine (3). It is used. The water (the temperature is several tens of degrees) heated by the cooling air cooler (5) is cooled by the air by the air cooling radiator (6). (7) is a circulating water pump.

[0003]

As the combustion temperature of the gas turbine increases, the cooling needs of the turbine rotor further increase. Further, cooling with air of lower temperature is required. Then, in the conventional cooling method, a large amount of heat is discharged to the cooling medium (water, atmosphere, etc.) outside the system, resulting in energy loss.

[0004]

In order to solve the above-mentioned conventional problems, the present invention cools a part of the compressed air at the compressor outlet with the fuel supplied to the combustor, and uses the cooled compressed air. A gas turbine characterized by cooling a turbine rotor is proposed.

[0005]

In the present invention, the air whose pressure is raised by the compressor is not cooled by water or the cooling medium of the atmosphere, but is cooled by the fuel of the gas turbine whose temperature is almost equal to the atmospheric temperature. The fuel cools the air and heats itself, becoming a fuel with a high energy level by the amount of sensible heat.

As described above, by using the fuel as the cooling medium, the energy which has been conventionally discarded outside the system through the cooling medium is used to raise the temperature of the fuel and stays in the system, thereby improving gas turbine efficiency and plant efficiency. Achieve improvement.

[0007]

FIG. 1 is a system diagram showing an embodiment of the present invention. In this figure, the same parts as those of the conventional one described with reference to FIG. 2 are designated by the same reference numerals to avoid redundancy, and detailed description thereof is omitted.

Most of the air whose pressure has been raised by the compressor (2) is introduced to the combustor (4) as combustion air, but a part of the air is introduced to the outside of the system to be cooled in the cooling air cooler (5). Heat exchange with water as an intermediate medium. The air that has been at the outlet of the compressor (2) at a temperature of three hundred and several tens degrees is cooled by water as an intermediate medium, and is cooled to a predetermined temperature, for example, around 200 degrees. Then, the cooled air cools the rotor of the turbine (3) and the like. On the other hand, the intermediate medium, water, is heated up to around 200 degrees. Then, the heat energy of water, which is a heated intermediate medium, is applied to the fuel by the fuel gas heater (8). That is, the water that has been heated to about 200 degrees C is cooled to near room temperature by the fuel of the gas turbine in the fuel gas heater (8), and then returns to the cooling air cooler (5) by the hot water circulation pump (9) and is compressed by the compressor. (2) Used to cool the outlet air. On the other hand, in the fuel gas heater (8),
The gas turbine fuel is heated to a temperature of hundreds of tens of degrees Celsius by the medium water. Therefore, as fuel, energy equivalent to the sensible heat difference between the temperature of hundreds of degrees and the atmospheric temperature,
It will be given in advance as heat input.

As described above, in this embodiment, the energy that was conventionally discarded outside the system can be retained inside the system by exchanging heat with the fuel, and the plant efficiency is improved.

In the above embodiment, a method of using water or the like as an intermediate medium has been described as a method of heat exchange between the fuel and the air whose pressure has been raised, but both may be directly heat-exchanged.

[0011]

INDUSTRIAL APPLICABILITY According to the present invention, plant efficiency and gas turbine efficiency can be improved by recovering energy, which was conventionally discarded outside the system, into the system.
As the temperature of the gas turbine rises, the need to cool the rotor continues to increase, but a considerable proportion of the energy is wasted outside the system due to the low temperature of the cooling air, hindering the efficiency improvement associated with higher temperatures. , It greatly contributes to the efficiency improvement by stopping the release to the outside of the system.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram showing an example of a conventional gas turbine.

[Explanation of symbols]

 (1) Gas turbine (2) Compressor (3) Turbine (4) Combustor (5) Cooling air cooler (6) Air-cooled radiator (7) Circulating water pump (8) Fuel gas heater (9) Hot water circulating pump

Claims (1)

[Claims] 1. A gas turbine characterized in that a part of compressed air at a compressor outlet is cooled by a fuel supplied to a combustor, and a turbine rotor is cooled by the cooled compressed air.