JPH0580575B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a gas turbine device that can be widely applied to boilers, power generation cycles, etc., and can effectively recover the amount of heat held in the cooling air of the gas turbine.

BACKGROUND ART Conventionally, in a gas turbine device, as shown in FIG. The gas is introduced into the gas turbine 2 and expands in the gas turbine 2 to generate power, and the expanded gas is discharged from the gas turbine 2 as an exhaust gas 10.

On the other hand, an air flow path that leads discharge air 6 from the compressor 1 to the combustor 3 is branched and connected to the air cooler 4,
The air cooler 4 exchanges heat with the discharged air 6 and the cooling water 8, and the cooled air 7 is introduced into the gas turbine 2.

By the way, in the gas turbine 2, according to thermodynamics, the thermal efficiency of the combustion gas that enters the gas turbine 2 increases as the temperature increases. Further, the pressure entering the gas turbine, that is, the compressor discharge pressure, has an appropriate value in terms of thermal efficiency and generated power depending on the gas turbine inlet temperature.

These values indicate that for modern gas turbines, the turbine inlet gas temperature is around 1200℃ or higher, and the compressor discharge air pressure suitable for this level of gas temperature is around 10au¨ or higher. be.

However, when the inlet temperature of the gas turbine 2 reaches the above-mentioned high temperature, some parts of the metal material that makes up the gas turbine 2 cannot withstand the strength, so the metal must be cooled to a temperature that the metal can withstand. Must be.

Therefore, in order to cool the metal, a portion of the compressor discharge air 6 or a bleed air (not shown) from the middle of the compressor is removed and sent to a portion of the interior of the gas turbine 2 that requires cooling.

Mainly, in large gas turbines used for power generation, martensitic alloy steel is often used as the material for the rotor of the gas turbine. This is mainly because austenitic alloys are preferable for rotor materials that require high strength at high temperatures, but austenitic high-strength alloys are extremely difficult to make into large objects such as those required for gas turbines. This is because the current market size makes it virtually impossible due to economic reasons regarding capital investment.

On the other hand, when using martensitic alloy steel, the temperature of the alloy should be raised to 350° to 400°, although there are slight differences depending on the steel type in terms of creep strength or embrittlement.
Must be limited to ℃. The compressor discharge air temperature reaches about 350℃ or higher when the atmospheric temperature is compressed to a pressure ratio of about 10 or more, so the cooling air is cooled to the appropriate temperature required for cooling performance (170℃ in one example). Must.

For the above reasons, in the one shown in Figure 2,
An air cooler 4 was installed to cool the cooling air, and cooling was performed using cooling water 8. Note that the air cooler 4 may be air-cooled.

When the cooling air is cooled by the air cooler 4 that exchanges heat with the cooling water 8, if the cooling water boils in the cooler 4, damage to the cooling pipes, instability of the amount of cooling water, loud noises, etc. occurs, so in order to prevent the cooling water from boiling, the amount of cooling water must be increased and the temperature difference must be designed to be small, so the outlet temperature of the cooling water must be low, and the calorific value of the cooling water 8 is relatively low. It is difficult to use hot water in the form of low-temperature water, and therefore the heat capacity of cooling air cannot be used effectively.

Problems to be Solved by the Invention The present invention was conceived in view of the above-mentioned current situation. Conventionally, hot water is produced in an air cooler in the form of hot water with a small temperature difference, making it difficult to use and being thrown away as is. The aim is to recover the heat retained in the cooling air in the form of steam, improving heat utilization efficiency.

Means for Solving the Problems In order to solve the above problems, the present invention provides a compressor that compresses air, a combustor that combusts the air supplied from the compressor together with fuel, and a combustor that combusts the air together with fuel. In a gas turbine device equipped with a gas turbine driven by generated combustion gas, a part of the discharge air from the compressor is introduced into a steam generator, and cooling air heat exchanged with the steam generator is used. The steam generated by the steam generator is introduced into the gas turbine and is also introduced into the steam recovery means.

Effect Since the present invention is configured as described above,
The intake air is compressed by the compressor, and the compressor discharge air is combusted with fuel in the combustor to become combustion gas, which is introduced into the gas turbine and expands in the gas turbine to generate power. It becomes exhaust gas and is exhausted. On the other hand, the discharge air from the compressor branches from the air flow path leading to the combustor and enters the steam generator, where it exchanges heat with feed water to become cooling air and is introduced into the gas turbine. The feed water heat-exchanged in the steam generator becomes steam and is introduced into the steam recovery means, where it is used for heating or power.

Embodiment A preferred embodiment of the present invention will now be described with reference to FIG.

In FIG. 1, 1 is a compressor, 2 is a gas turbine, and both are coaxially connected. A combustor 3 is connected to the compressor 1 and the gas turbine 2 through a pipe line, and generates combustion gas by receiving fuel 5 and compressor discharge air 6. Reference numeral 13 denotes a steam generator, which is connected to a branched pipe line that leads the discharge air 6 from the compressor 1 to the combustor 3, and which connects the discharge air 6 to the water supply 11.
At the same time, the heat exchanged feed water 11 generates steam 12. The steam generator 11 is connected to a pipe line that introduces cooling air after heat exchange of the compressor discharge air into the gas turbine. Note that 9 is the intake air of the compressor 1, and 10 is the exhaust of the gas expanded by the gas turbine 2.

Next, the operation of the gas turbine device configured as described above will be explained.

Intake air 9 is compressed by compressor 1 and discharged from the compressor, and discharge air 6 enters combustor 3. The compressor discharge air 6 burns together with the fuel 5 supplied in the combustor 3 to become combustion gas, and the combustion gas is transferred to the gas turbine 2.
is introduced into the gas turbine 2 and expands in the gas turbine 2 to generate power. The gas that has finished expanding is discharged into the atmosphere as exhaust gas 10. On the other hand, compressor discharge air 6
The cooling air 7 is branched from the air flow path leading to the combustor 3 and enters the steam generator 13 , where it exchanges heat with the feed water 11 and the cooling air 7 is introduced into the gas turbine 2 . The feed water 11 that has undergone heat exchange in the steam generator 13 evaporates and becomes steam 12. In one example, this steam is 2.
6atu¨ of saturated steam (approximately 140℃), 4.34T/H
The amount of evaporation was The steam 12 is then introduced to a steam recovery means (not shown) for heating or power use.

Effects of the Invention As described in detail above, according to the present invention, by providing a steam generator in place of a conventional air cooler, the amount of heat released from cooling air is recovered in the form of steam. It is suitable for heating, and is also suitable for steam conditions commonly used for process and small-scale power applications. Furthermore, in the case of power recovery, it can also be used to drive a steam turbine.

In addition, in the combined cycle, in which the exhaust gas of the gas turbine is put into a waste gas boiler to generate steam and drive the steam turbine, there is no need to install a new water pump or steam turbine, and the steam generation is performed at a stage midway through the steam turbine. It is possible to recover the power by introducing it into the system, which is very advantageous in terms of investment efficiency.

In the case of a steam generator, the steam temperature is uniquely determined by the pressure in the case of saturated steam, so by controlling the steam pressure, it is practically possible to control the cooling air temperature with sufficient accuracy. or,
If there is an existing constant pressure header, the pressure control, ie the cooling air outlet temperature control, can be omitted by connecting a steam pipe to the header.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the gas turbine device of the present invention, and FIG. 2 is a system diagram of a conventional gas turbine device. 1... Compressor, 2... Gas turbine, 3... Combustor, 4... Air cooler, 5... Fuel, 6... Compressor discharge air, 7... Cooling air, 8... Cooling water,
9...Intake, 10...Exhaust, 11...Water supply, 1
2...Steam, 13...Steam generator.

Claims (1)

[Claims] 1. In a gas turbine device equipped with a compressor that compresses air, a combustor that burns the air supplied by the compressor together with fuel, and a gas turbine that is driven by the combustion gas generated in the combustor. , a part of the discharge air from the compressor is introduced into a steam generator, cooling air heat exchanged with the steam generator is introduced into the gas turbine, and the steam generated in the steam generator is steam-recovered. A gas turbine device characterized in that it is introduced into a means.