JP2003056364A - Gas-fired gas turbine power generation equipment - Google Patents

Abstract

(57) [Problem] To provide a gas-fired gas turbine power generation equipment capable of reducing energy loss due to gas compression of a low calorie gas fuel and thereby increasing total power generation efficiency. A low-pressure fuel injection device for injecting gaseous fuel 1 into air before compression at a flammable limit or less, a high-pressure fuel injection device for injecting additional fuel 6 at a high pressure into a combustor, A catalytic combustor 20 for catalytically combusting the fuel component. Preferably, gas fuel 1 is a low calorie gas fuel and the additional fuel is a liquid fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-fired gas turbine power generation facility using low-calorie gas as a main fuel.

[0002]

2. Description of the Related Art FIG. 2 is an overall configuration diagram of a conventional gas-fired gas turbine power generation facility. In this figure, 10 is
Compressor 11, combustor 12, turbine 13 and generator 14
Gas turbine generator consisting of, 15 is a gas compressor, 16
Is a gas cooling control device, and 17 is a heat exchanger. The gas fuel 1 is pressurized (for example, about 18 atm) by the gas compressor 15, cooled by the gas cooling control device 16 including a cooler, an oil separator, a flow control valve, and the flow rate is controlled to be high pressure (for example, about 12 atm). Is injected into the combustor 12. The compressor 11, the turbine 13, and the generator 14 are mechanically connected to each other. The compressor 11 compresses the air 2 and the combustor 12 burns the pressurized gas fuel 1 to generate a combustion exhaust gas 3.
The combustion exhaust gas 3 drives the turbine 13 to rotate, and the power thereof drives the compressor 11 and the generator 14 to generate power.
Further, the heat exchanger 17 cools the high temperature combustion exhaust gas 3 to generate steam 5, and the steam 5 is injected into the combustor 12 to increase the power generation output. In this figure, 2a is extraction air, and 4 is cooling water.

[0003]

As described above, in the gas-fired gas turbine power generation facility, the gas fuel 1 is supplied to the combustor 12
Pressure in the combustor (eg 12 atm) to inject
It is necessary to compress to a pressure sufficiently higher than that (for example, 18 atm), and therefore the gas compressor 15 is used.
However, the required power of the gas compressor 15 is about 5% (about 100 k) of the power generation output (eg, about 2000 kW) even when a high-calorie gas fuel (eg, natural gas) is used.
W) has been reached.

The temperature of the gas fuel compressed by the gas compressor 15 is high (for example, about 500 ° C.) and contains compressor oil. Therefore, if it is left as it is, the oil separator, the flow rate control valve, and the like that form the gas cooling control device 16 do not withstand high temperatures, and if they are burned as they are, the turbine 13 may be damaged. Therefore, water cooling is performed until the gas temperature reaches around 100 ° C., and the compressor oil is removed by the oil separator. As a result, energy loss and pressure loss in the oil separator occur due to water cooling, and most of the gas compressor power is lost.

Further, when a low-calorie gas fuel is used as the gas fuel 1, generally, the low-calorie gas fuel is C
Since it contains a large amount of non-combustible components such as O ₂ , steam, and nitrogen, the lower the calorie, the larger the amount of gas that is compressed and injected, so the compression power increases and the loss increases.

FIG. 3 is a diagram showing this relationship, in which the horizontal axis represents the calorific value of gas fuel, and the vertical axis represents gas compression power and total power generation efficiency. The gas compression power (right vertical axis) has LNG of 1, and the total power generation efficiency has liquid burning of 1. As can be seen from this figure, the gas-fired gas turbine power generation equipment uses a gas compressor to inject gas into the combustor, and its large power reduces the net power generation efficiency, especially biomass gas and sludge digestion. When a low-calorie gas such as gas is used, the gas compression power is significantly increased, so that there is a problem that the loss reaches several percent of the power generation output.

The present invention was created to solve such problems. That is, an object of the present invention is to provide a gas-fired gas turbine power generation facility that can reduce energy loss associated with gas compression of low-calorie gas fuel and thereby increase total power generation efficiency.

[0008]

According to the present invention, a compressor (11) compresses air (2) and a combustor (12) burns a gas fuel (1) to produce a combustion exhaust gas (3). The combustion exhaust gas is driven to rotate to drive the turbine (13) to rotate the compressor and the generator (14) to rotate, and the heat exchanger (17) cools the combustion exhaust gas to generate steam (5). A low pressure fuel injection device (18) for injecting gas fuel (1) into the air before compression below a flammable limit in a gas-fired gas turbine power generation facility for injecting into the combustor to increase power generation output,
A gas characterized by comprising a high-pressure fuel injector (19) for injecting additional fuel (6) at high pressure into the combustor, and a catalytic combustor (20) for catalytically burning unburned components in the combustion exhaust gas. A gas turbine power generation facility is provided.

According to a preferred embodiment of the present invention, the gas fuel (1) is a low-calorie gas fuel and the additional fuel is a liquid fuel.

According to the above-mentioned configuration of the present invention, the gas fuel (1) (low-calorie gas fuel) is injected into the air before compression, so that the conventional gas compressor and gas cooling control device can be omitted. The device can be simplified, the compression power can be reduced, and the energy loss due to cooling and pressure loss can be eliminated. Since the injection amount is less than the flammability limit, ignition of gas fuel in the compressor (11) can be essentially prevented.

Further, since the additional fuel (6) is injected into the combustor at a high pressure, the premixture below the lean flammability limit and the additional fuel (6) are mixed to form a fuel gas in the flammable range, which is stabilized. It can be burned and flame-retained. In addition,
Liquid fuel such as kerosene, which does not require a gas compressor, is desirable as the additional fuel in the combustor, but even when gas fuel is used, it has the effect of significantly reducing the capacity of the gas compressor.

Further, although gas fuel is mixed in the extracted air, it can be catalytically burned in the catalytic combustor (20) and energy can be recovered as steam in the heat exchanger (17). That is, unburned components due to turbine cooling and the like are burned in the catalytic combustor downstream of the turbine, and the exhaust gas temperature thereof is slightly raised by the catalytic reaction, so steam is generated in the heat exchanger,
High efficiency can be achieved by injecting steam to the combustor.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are used for the common parts in each drawing.

FIG. 1 is an overall configuration diagram of the gas-fired gas turbine power generation equipment of the present invention. As shown in this figure, the gas-fired gas turbine power generation facility of the present invention includes a gas turbine generator 10 including a compressor 11, a combustor 12, a turbine 13, and a generator 14, and a heat exchanger 17, and the compressor 11 To compress the air 2 and to combust the gas fuel 1 in the combustor 12 to generate the combustion exhaust gas 3. The combustion exhaust gas 3 rotationally drives the turbine 13 to rotationally drive the compressor 11 and the generator 14 to generate a generator. Power is generated in 14, the combustion exhaust gas 3 is cooled in the heat exchanger 17, steam 5 is generated, and the steam 5 is injected into the combustor 12 to increase the power generation output. Although the compressor 11, the turbine 13, and the generator 14 are mechanically connected coaxially in this example, they may be connected via a gear or the like.

In FIG. 1, the gas-fired gas turbine power generation equipment of the present invention further comprises a low pressure fuel injection device 18, a high pressure fuel injection device 19 and a catalytic combustor 20. Gas fuel 1
Is, in the present invention, biomass gas, sludge digestion gas,
Low calorie gas fuels such as coal gasification gas are suitable, but the present invention can also be applied to high calorie gas fuels such as LPG and LNG.

The low-pressure fuel injection device 18 injects the gas fuel 1 into the air before compression below the flammability limit. That is, the low-pressure fuel injection device 18 controls so that the mixed gas of the gas fuel 1 and the air 2 becomes a premixed gas that is less than the lean combustible limit that cannot self-combust. At the same time, in order to maintain the rotation speed of the generator 14, the gas fuel 1
Control the flow rate of.

The high-pressure fuel injection device 19 injects the additional fuel 6 into the combustor at high pressure. The additional fuel 6 is preferably a liquid fuel such as kerosene in order to minimize the pressurizing power, but a gas fuel may be used. When a liquid fuel such as kerosene is used, the high-pressure fuel injection device 19 is composed of a hydraulic pump and its flow control valve. When using gas fuel, the high-pressure fuel injection device 19 comprises a small gas compressor and its flow control valve.

The catalytic combustor 20 is provided in the gas flow path between the turbine 13 and the heat exchanger 17. This catalytic combustor 2
0 has a combustion catalyst layer inside and has a relatively low temperature (for example, 2
It is designed to catalytically burn unburned components in flue gas at temperatures above 00 ° C. In the configuration of the present invention, the gas fuel 1 is mixed in the extracted air 2a introduced into the turbine 13. Therefore, the gas fuel 1 does not pass through the combustor 12 and remains as it is in the exhaust gas of the turbine 13 as an unburned component, which burns in the catalytic combustor 20 to raise the temperature of the exhaust gas and the steam in the heat exchanger 17. It is designed to recover heat.

According to the above-described configuration of the present invention, the gas fuel 1 (low-calorie gas fuel) is injected into the air before compression by the low-pressure fuel injection device 18, so that the conventional gas compressor and gas cooling control device can be used. It can be omitted, the device can be simplified, the compression power can be reduced, and the energy loss due to cooling and pressure loss can be eliminated. Since the injection amount is below the flammability limit, ignition of the gas fuel 1 in the compressor 11 can be essentially prevented.

Since the high pressure fuel injection device 19 injects the additional fuel 6 into the combustor 12 at a high pressure, the premixture below the lean flammability limit and the additional fuel 6 are mixed to form a fuel gas in the combustible range. This can be stably burned and flame-retained. Liquid fuel such as kerosene that does not require a gas compressor is desirable as the additional fuel in the combustor, but even when gas fuel is used, it has the effect of significantly reducing the gas compressor capacity.

Further, although the gas fuel 1 is mixed in the extracted air 2a, it is catalytically burned in the catalytic combustor 20 and the energy is recovered as steam in the heat exchanger 17, so that the steam is injected into the combustor 12. As a result, high efficiency can be achieved.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0023]

As described above, in the present invention, in order to eliminate the loss due to the gas compressor, gas fuel injection is performed from the compressor inlet. Further, the working fluid of the compressor becomes a premixed gas, which is kept below the flammability limit to prevent its ignition, and the combustion and flame holding are performed by the injection of the additional fuel in the combustor. Further, unburned components due to turbine cooling and the like are removed by a catalytic combustor downstream of the turbine, and the recovered energy is injected into the combustor to improve efficiency.

Therefore, the gas-fired gas turbine power generation equipment of the present invention has an excellent effect that energy loss due to gas compression of low-calorie gas fuel is reduced, and thereby total power generation efficiency can be increased.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a gas-fired gas turbine power generation facility of the present invention.

FIG. 2 is a configuration diagram of a conventional gas-fired gas turbine power generation facility.

FIG. 3 is a relationship diagram of the calorific value of gas fuel, gas compression power, and total power generation efficiency.

[Explanation of symbols]

1 gas fuel, 2 air, 2a extraction air, 3 combustion exhaust gas, 4 cooling water, 5 steam, 6 additional fuel, 10
Gas turbine generator, 11 compressor, 12 combustor, 1
3 turbines, 14 generators, 15 gas compressors, 16
Gas cooling control device, 17 heat exchanger, 18 low pressure fuel injection device, 19 high pressure fuel injection device, 20 catalyst combustor

Claims (2)

[Claims] 1. A compressor (11) compresses air (2),
The combustor (12) burns the gas fuel (1) to generate combustion exhaust gas (3), and the combustion exhaust gas rotationally drives the turbine (13) to rotationally drive the compressor and the generator (14) to generate heat. In a gas-fired gas turbine power generation facility in which a combustion exhaust gas is cooled by an exchanger (17) to generate steam (5) and the steam is injected into the combustor to increase power generation output, the gas fuel (1) is compressed before compression. A low pressure fuel injector (18) for injecting into the air below the flammability limit, a high pressure fuel injector (19) for injecting additional fuel (6) into the combustor at high pressure,
A gas-fired gas turbine power generation facility comprising a catalytic combustor (20) for catalytically burning unburned components in combustion exhaust gas. 2. The gas-fired gas turbine power generation facility according to claim 1, wherein the gas fuel (1) is a low-calorie gas fuel, and the additional fuel is a liquid fuel.