JPH0220438Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a gas turbine starting device for starting a gas turbine in an apparatus for gasifying coal and combusting the gas to operate the gas turbine.

[Background of the idea]

BACKGROUND ART In a gas turbine operating device that burns coal gas to drive a gas turbine and rotate a generator, there is a problem when starting the device. This will be explained using a diagram.

FIG. 3 is a system diagram of a conventional gas turbine operating device. In the figure, 1 is a coal supply facility, 2 is a gasifier that gasifies the coal supplied from the coal supply facility 1 to generate coal gas, and 3 is a gas that removes impurities from the coal gas generated in the gasifier 2. purification equipment,
4 is a gas combustor that burns the gas supplied from the gas purification device 3; 5 is a gas turbine driven by the gas combusted in the gas combustor 4;
6 is a generator operated by the gas turbine 5, 7
is the HRSG and 8 is the chimney. Reference numeral 9 denotes a compressor that is rotationally driven by the gas turbine 5 to compress air, and the compressed air from the compressor 9 is supplied to the gasifier 2 through the extraction line a, and is also supplied to the gas combustor 4. . 10 is an auxiliary fuel supply device that supplies gas or oil to the gas combustor 4. Large-scale power generation gas turbines require a combustion pressure of approximately 20 to 27 atm in order to improve their efficiency, and in conjunction with this, the gasifier pressure is approximately 22 to 30 atm. Since the gas turbine operating system as described above is generally well known, a description of its steady operation will be omitted, and the operation at startup will be described.

At startup, since the gas turbine 5 is not driven, the compressor 9 cannot be driven, and therefore compressed air cannot be supplied to the gasifier 2 and the gas combustor 4. Therefore, at startup, the auxiliary fuel supplied from the auxiliary fuel supply device 10 is combusted to drive the gas turbine 5, and after the compressor 9 reaches a predetermined rotation speed, compressed air begins to be extracted to the gasifier 2. , start the gasifier 2,
After that, it enters a steady operating state.

However, the above-mentioned startup method has a drawback in that a large amount of auxiliary fuel is required to be supplied from the auxiliary fuel supply device 10. In addition, when the gas turbine 5 is stopped due to a trip on the gas turbine 5, the generator 6, or the place where the electric power is used,
The compressor 9 also has to be stopped and the supply of compressed air to the gasifier 2 has to be stopped, which also has the disadvantage that it takes a long time to bring the system into steady operation when the trip is restored. Ta.

[Purpose of invention]

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art,
To provide a gas turbine starting device which does not require auxiliary fuel at the time of starting and can quickly enter steady operation even at the time of trip recovery.

[Summary of the idea]

In order to achieve the above object, the present invention provides a second compressor with a small capacity driven by an electric motor and a gas turbine, and switches the gas by the first switching device at necessary times such as startup or restart. The compressed air is introduced into the gas turbine, and the compressed air from the second compressor is introduced into the gasifier by a second switching device.

[Example of idea]

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 1 is a system diagram of a gas turbine starting device according to an embodiment of the present invention. In the figure, the same parts as those shown in FIG. 3 are given the same reference numerals. Reference numeral 12 denotes a small compressor for starting, which is driven by both an electric motor and a gas turbine. 13a is a switching valve that opens and closes a gas line from the gas purification device 3 to the gas combustor 4, and 13b is a switching valve that opens and closes a gas line from the gas purification device 3 to the gas turbine of the small compressor 12. Further, 14a is a switching valve that opens and closes the bleed air line a, and 14b is a switching valve that opens and closes a line that sends compressed air from the small compressor 12 to the bleed air line a.

Next, the operation of this embodiment will be explained with reference to the startup curve shown in FIG. In FIG. 2, time is plotted on the horizontal axis, and gasifier pressure and gasifier coal throughput are plotted on the vertical axis. The solid line C ₁ shows the gasifier pressure, and the broken line C ₂ shows the gasifier coal throughput. Now, when starting up the system at time _t1 , the switching valves 13a and 14a are closed and the switching valves 13b and 14b are opened. Next, the small compressor 12 is driven by the electric motor, and the compressed air is supplied to the gasifier 2 through the switching valve 14b. On the other hand, coal is supplied to the gasifier 2 from the coal supply facility 1, and gasification of the coal is performed by supplying compressed air. At this time, the gasifier is at normal pressure to
Operated by low pressure of several atm. Therefore, the capacity of the small compressor 12 may be small, and the coal processing amount of the gasifier 2 is set to about 5 to 20% of the steady load.

The gas produced in the gasifier 2 is sent to the gas turbine of the small compressor 12 through the open switching valve 13b. At time _t2 , the drive of the small compressor 12 is switched from the electric motor to the gas turbine and the operation continues. During this time, the pressure in the gasifier 2 gradually increases and finally reaches the permissible pressure of the gas turbine 5 of 10 to 15 atm. After rising to this pressure, at time t ₃ the switching valve 13
a, 14a and close the switching valves 13b, 14b to start the gas turbine 5, rotate the compressor 9 to supply compressed air from the extraction line a to the gasifier 2, and stop the small compressor 12. urge Due to this operation, the pressure in the gasifier 2 increases rapidly, the coal processing also increases, and the system enters normal operation. With such a starting device, no auxiliary fuel is required during starting.

Next, during steady operation, the gas turbine 5,
If a failure occurs in the generator 6 or the power system and the trip is activated, the switching valves 13a and 14a are closed and the switching valve 13
b, 14b are opened, and the electric motor drives the small compressor 12.
Start. Thereafter, the gasifier 2 is
The gas turbine 5 is operated independently at a low load, and when the failure is recovered, the switching valves 13a and 14a are immediately opened, the switching valves 13b and 14b are closed, and the gas turbine 5 is started. Therefore, after the failure is recovered, the system can quickly resume steady operation.

In this way, in this embodiment, since a small compressor and a switching valve are provided, auxiliary fuel is not required at the time of startup, and it is possible to quickly return to normal operation when recovering from a failure. In addition, in conventional gas turbine operation systems, air is extracted to the gasifier and the gas after gasification is combusted in the gas combustor. Control is required in two places,
Since compressed air was supplied to these two locations from the same air source, it was extremely difficult to control it. However, if the small compressor of the present invention is used appropriately, its control becomes extremely easy.

[Effects of the invention] As described above, in the present invention, a second compressor driven by an electric motor and a gas turbine is provided,
By using a switching valve, the gasifier is operated by this second compressor at startup, so there is no need for auxiliary fuel, and it is possible to quickly return to normal operation after recovery from a failure. , Furthermore, control of system operation can be facilitated.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a gas turbine starting device according to an embodiment of the present invention, FIG. 2 is a starting curve of the gas turbine shown in FIG. 1, and FIG. 3 is a system diagram of a conventional gas turbine operating device. 1... Coal supply equipment, 2... Gasifier, 3...
Gas purification device, 4... Gas combustor, 5... Gas turbine, 6... Generator, 9... Compressor, 12...
Small compressor, 13a, 13b, 14a, 14b...
...Switching valve.

Claims (1)

[Scope of utility model registration request] Coal is gasified by a gasifier, this gas is supplied to a gas turbine through a gas supply path, and compressed air is supplied to the gasifier through a compressed air supply path by a first compressor connected to the gas turbine. In a gas turbine operating device, a second compressor driven by an electric motor and a gas turbine, and a first switch that switches a gas passage through the gas supply path to a passage to a gas turbine that drives the second compressor. and a second switching device that switches the compressed air passage through the compressed air supply path to a passage from the second compressor to the gasifier.