JP2000087761A - Gas turbine output enhancement unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase thermal efficiency within the partial load operating range where the design point is not exceeded, and, in the operating range where the design point is exceeded, increase thermal efficiency in the design point side operating range. SOLUTION: This gas turbine is provided with a compressor 1, a turbine 2, and a combuster 3. In this gas turbine, the compressor 1 is connected to a shaft 4 of the turbine 2, an air outlet of the compressor 1 is connected to the air outlet of the combuster 3, and the gas outlet of the combuster 3 is connected to the gas inlet of the turbine 2. This gas turbine is also provided with a pre-pressurizing air compressor 21 that puts the design point of the gas turbine in the partial load operating range and pressurizes the air taken into the air inlet of the compressor 1 where the design point is exceeded, and a rotary drive unit 22 to drive the pre-pressurizing air compressor 21. This gas turbine further comprises a control unit 28 which obtains the desired output by controlling the pressure ratio of the pre-pressurizing compressor 21 by adjusting the rotational speed of the pre-pressuring compressor 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for enhancing the output of a gas turbine.

[0002]

2. Description of the Related Art The inventor of the present invention has proposed a vehicle having a wide driving range,
The present invention has invented a gas turbine output augmenting device suitable for a power source in which most of the operation area is a partial load operation, such as a small generator that varies the amount of power generation according to demand.

As disclosed in Japanese Patent Application No. 10-249894, the present invention includes a compressor, a turbine, and a combustor, connects a compressor and a turbine shaft, and connects an air outlet of the compressor to air of a combustor. In a gas turbine in which the gas outlet is connected to the inlet and the gas outlet of the combustor is connected to the gas inlet of the turbine, the design point of the gas turbine is set to the frequently used partial load operation area. This is an output booster provided with a preload device that compresses the air sucked into the inlet.

[0004] This power booster has high thermal efficiency in a partial load operation region not exceeding a design point. In an operation region exceeding the design point, the air taken into the compressor is compressed and pre-pressed, so that the output is increased and the thermal efficiency is not significantly reduced. Full load operation is possible. Further, the gas turbine becomes smaller and lighter.

[0005]

However, in the above-described gas turbine power booster, various types of drive devices and control methods for the preload device are conceivable, and accordingly, the performance in the operating region exceeding the design point is correspondingly considered. Is different.

On the other hand, when the frequency of use in an operation region exceeding a design point is examined in an automobile having a wide operation region or a small generator in which the amount of power generation is varied according to demand, it is found that the operation region is smaller than the operation region on the full load operation side. It is often used frequently in the operating area on the point side.

[0007] Therefore, the power increase device of the gas turbine is
In an operation region exceeding the design point, a high-performance one in the operation region on the design point side is desired.

[0008]

In the above-described gas turbine power booster, when the air compressor of the precompression device is rotationally driven in an operation region exceeding the design point, the preloading device is used when the operation region exceeds the design point. It is conceivable to connect the shaft of the air compressor to the turbine shaft with a clutch. However, since the clutch has a large slip loss at the time of connection, the performance deteriorates stepwise when the operating range exceeds the design point, and the performance does not become high in the operating range slightly beyond the design point.

Therefore, when the operating range exceeds the design point, it is conceivable to drive the preload air compressor not by the turbine shaft but by a rotary drive device such as an electric motor, a hydraulic motor or a pneumatic motor.

[0010] The power loss of such a rotary drive is very small compared to the slip loss when the clutch is engaged.

When the rotation speed of the precompression air compressor is changed to change the ratio of the outlet pressure to the inlet pressure, ie, the pressure ratio, the output of the gas turbine increases and decreases as illustrated in FIG. The thermal efficiency is higher in the operation area on the design point side than in the operation area on the full load operation side.

Accordingly, the precompression air compressor is driven by the rotary drive device, and the pressure ratio of the precompression air compressor is controlled by the rotation speed of the precompression air compressor to set the output of the gas turbine to a desired value. Then, in the operation region exceeding the design point, the performance becomes high in the operation region on the design point side.

[0013]

SUMMARY OF THE INVENTION The present invention comprises a compressor, a turbine, and a combustor, wherein a shaft of the compressor is connected to a shaft of the turbine, and an air outlet of the compressor is connected to an air inlet of the combustor. In a gas turbine with the gas outlet connected to the gas inlet of the turbine, the design point of the gas turbine is set to the partial load operation area, and in the operation area exceeding the design point, the precompression for compressing the air taken into the air inlet of the compressor A control device for providing a desired output by controlling the pressure ratio of the pre-compressed air compressor with the rotational speed of the pre-compressed air compressor by providing an air compressor and providing a rotational drive device for rotating the pre-compressed air compressor. An output intensifying device characterized by being provided.

[0014]

According to the present invention, the thermal efficiency is increased in the partial load operation region not exceeding the design point. In the operation region beyond the design point, the thermal efficiency is high in the operation region on the design point side.

Therefore, most of the operation range is the partial load operation, and the operation range exceeding the design point is suitable for a power source that is more frequently used in the operation range on the design point side than the operation range on the full load operation side. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (See FIGS. 2 and 3) The gas turbine of this embodiment includes a compressor 1, a turbine 2, and a combustor 3, as shown in FIG. The compressor 1 and the turbine 2 connect their shafts 4. An air inlet of the compressor 1 is open to the atmosphere via an air suction passage 5. An air outlet of the compressor 1 is connected to an air inlet of the combustor 3 by an air passage 6. A fuel supply passage 8 is connected to the fuel injection valve 7 of the combustor 3. The gas outlet of the combustor 3 is connected to the gas inlet of the turbine 2 by a gas passage 9. The gas outlet of the turbine 2 is open to the atmosphere via a gas discharge passage 10. A small load generator 11 having a load is connected to the turbine shaft 4. The design point of the gas turbine is at 2/3 load operation.

As shown in FIG. 2, the power intensifier of this embodiment comprises a preloading turbo air compressor 21 and an electric motor 22, a pressure sensor 23 and a rotational speed sensor 24, a first directional control valve 2
5, second directional control valve 26, output sensor 27 and control device 2
8 is provided.

The precompression air compressor 21 and the electric motor 22 have their shafts 31 connected. The first directional switching valve 25 and the second directional switching valve 26 are respectively provided in the middle of the air suction passage 5 of the compressor 1. An outlet of the first directional control valve 25 is connected to an air inlet of the precompression air compressor 21 through a precompression air intake passage 32. The air outlet of the preload air compressor 21 is connected to the inlet of the second directional control valve 26 through a preload air passage 33.

A pressure sensor 23 for detecting an outlet pressure of the precompression air compressor 21, a precompression air compressor 21 and an electric motor 22
A rotation speed sensor 24 for detecting the rotation speed of the shaft 31 of
Output sensors 27 for detecting the output state of the generator 11 are connected to input terminals of a control device 28, respectively. The output terminal of the control device 28 is connected to the fuel injection valve 7, the electric motor 22, the first directional switching valve 25 and the second directional switching valve 26 of the combustor 3, respectively.

In the gas turbine provided with the power booster of this embodiment, the output of the generator 11 is two thirds of the gas turbine design point.
During the low-load operation until the load is reached, the first directional control valve 25 and the second directional control valve 26 are in the passage connection state shown in FIG. The air inlet and the air outlet of the precompression air compressor 21 are closed, and the air inlet of the compressor 1 is connected to the air suction passage 5.
And open to the atmosphere. The electric motor 22 does not rotate. Therefore, the power booster does not operate. The gas turbine operates as if there were no power booster.

When the output of the generator 11 is higher than 2/3 of the design point of the gas turbine at a high load operation, the control unit 28
Switches the passages of the first directional switching valve 25 and the second directional switching valve 26 from the passage connection state shown in FIG. Then, the middle of the air suction passage 5 is closed, and the air inlet of the precompression air compressor 21 is opened to the atmosphere via the precompression air suction passage 32, the first directional switching valve 25, and the upstream portion of the air suction passage 5. The air outlet of the precompression air compressor 21 is connected to the air inlet of the compressor 1 via the precompression air passage 33, the second directional control valve 26, and the downstream portion of the air suction passage 5. Further, the control device 28 drives the electric motor 22 to rotate, and drives the preload air compressor 21.

Then, the air sucked into the air inlet of the compressor 1 flows into the air inlet of the compressor 1 while being compressed in the pre-compression air compressor 21. Since the air flowing into the compressor 1 is pre-pressed, that is, supercharged, the air flow rate of the compressor 1 increases, and the output of the gas turbine is increased.

When controlling the output of the gas turbine, the rotation speed of the electric motor 22, that is, the rotation speed of the precompression air compressor 21 is changed to change the pressure ratio of the precompression air compressor 21.

FIG. 3 shows the relationship between the thermal efficiency and the output of the gas turbine provided with the power booster of this embodiment by a solid line. A broken line shows a comparative example in which the shaft of the preload air compressor is connected to the turbine shaft by a clutch when the operating range exceeds the design point.

As is apparent from the diagram of FIG. 3, in the case of this embodiment, the thermal efficiency is high during the low-load operation where the frequency of use is high until the load (100 kW) of the gas turbine design point is reached.

At the time of high-load operation exceeding two-thirds load at the gas turbine design point, the thermal efficiency gradually decreases as the load increases, but full-load (150 kW) operation is possible. In the operation region beyond the design point, the thermal efficiency is higher in the operation region on the design point side than in the operation region on the full load side.

In the case of the comparative example, when the operating region exceeds the design point, the thermal efficiency deteriorates stepwise due to a large slip loss when the clutch is engaged, and in the operating region slightly beyond the design point, the thermal efficiency decreases. Is much lower than

The gas turbine of this embodiment can be started by driving the preload air compressor 21 instead of the starter, so that the starting time can be reduced and the power consumption can be reduced.

In this embodiment, a turbo type is used as the preload air compressor 21, but a roots type or a screw type may be used.

[Second Example (See FIG. 4)] The power intensifier of the present example differs from that of the first example in that the air inlet of the compressor 1 or the air of the precompression air compressor 21 as shown in FIG. An air cooler 41 is interposed at the outlet to cool the air that is compressed by the precompression air compressor 21 and flows into the air inlet of the compressor 1. Other configurations are the same as those in the first example.

In the gas turbine provided with the power booster of the present embodiment, at the time of high load operation exceeding two-thirds load,
Since the air taken into the compressor 1 is cooled by the air cooler 41, the air mass flow rate of the compressor 1 increases, and the output of the gas turbine is further enhanced.

[Brief description of the drawings]

FIG. 1 is a diagram exemplifying the relationship between the thermal efficiency of a gas turbine provided with an output booster of the present invention, the pressure ratio of a precompression air compressor, and the output of a gas turbine.

FIG. 2 is a schematic diagram of a gas turbine including a power booster according to a first embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between thermal efficiency and output of the gas turbine.

FIG. 4 is a schematic diagram of a gas turbine including a power booster according to a second example of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Turbine 3 Combustor 4 Turbine shaft 21 Turbo air compressor for preload 22 Electric motor, rotation drive device 28 Control device

Claims (1)

[Claims] A compressor, a turbine, and a combustor; a compressor and a turbine shaft connected to each other; an air outlet of the compressor connected to an air inlet of the combustor; and a gas outlet of the combustor connected to a gas inlet of the turbine. In the gas turbine connected to the gas turbine, the design point of the gas turbine is set to the partial load operation area, and in the operation area exceeding the design point, a precompression air compressor that compresses the air taken into the air inlet of the compressor is installed. Providing a rotary drive for rotating the air compressor,
An output intensifier comprising a control device for controlling a pressure ratio of the preload air compressor at a rotation speed of the preload air compressor to obtain a desired output.