JP2869070B2 - Gas turbine unit for electricity and heat generation and method of operation thereof - Google Patents

Description

The present invention relates to a gas turbine unit for simultaneously generating electricity and heat and a method for operating the same.

[Problems of conventional technology and invention]

A gas turbine unit for simultaneously generating electricity and heat, for example heat such as hot water for a remote heating network, is required to satisfy the following requirements. That is, a requirement for high electrical efficiency, high overall thermal efficiency, high electrical-to-thermal relationship, flexibility between the generation of electricity and heat, insensitivity to changes in ambient temperature, and the like. These requirements include a combustion chamber, a high pressure gas turbine driven by combustion gases from the combustion chamber, a low pressure compressor driven by a low pressure gas turbine, and a series of low pressure compressors for supplying compressed air to the combustion chamber. A high-pressure compressor arranged and driven by a high-pressure gas turbine, a generator driven by the high-pressure gas turbine to generate electricity, and for performing heat exchange between the exhaust gas and compressed air from the high-pressure compressor. It is largely satisfied by a two-shaft gas turbine unit consisting of a recuperator, an intermediate cooler that produces hot water between the low and high pressure compressors, and an exhaust gas heat exchanger for producing hot water.

Electricity is generated by a generator connected to the shaft of a high pressure gas turbine, and hot water in the range of 70 to 120 ° C is generated in an intermediate cooler and exhaust gas heat exchanger. The shaft of the high-pressure gas turbine rotates at a constant speed, and the shaft of the low-pressure gas turbine can rotate freely.

Given the thermodynamic process in such gas turbine units, such gas turbine units
It can be conveniently defined as a recuperated exhaust gas turbine with an intermediate cooler, and has an electrical efficiency of 30 to 40 percent, which is better than a simple gas turbine operating at the corresponding turbine inlet temperature It is. Since the heat recovered by the intermediate cooler and the exhaust gas heat exchanger is used for producing hot water, high overall efficiency can be obtained.

[Means for solving the problem]

An object of the present invention relates to a method of operating a gas turbine unit as described above, and in order to satisfy the rest of the above requirements, the present invention provides a method for operating a low-pressure gas turbine at a constant temperature of the combustion chamber to reduce the rotational speed of the low-pressure gas turbine. A method of operating a gas turbine unit comprising: adjusting power to a desired value by changing a geometry of a gas turbine; and adjusting heat power to a desired value by controlling a flow bypassing a recuperator. Is provided.

The present invention further provides a gas turbine unit capable of performing the method of the present invention, wherein the gas turbine unit has an adjustable geometry in which a low-pressure gas turbine has an adjustable geometry and bypasses a recuperator. It is characterized by having a possible connecting pipe part.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a gas turbine unit according to the present invention comprises a high-pressure gas turbine 10, which is connected to a high-pressure compressor 11 and for recovering effectively used power from the gas turbine unit. Is connected to the generator 12 via a gear train or the like. The gas turbine unit further comprises a low-pressure gas turbine 13, which is connected to a low-pressure compressor 14. A regulator 15 for adjusting the geometry of the low-pressure gas turbine 13 is provided between the high-pressure gas turbine 10 and the low-pressure gas turbine 13.

A combustion chamber (boiler) 16 is connected at its gas outlet to the high-pressure gas turbine 10, and supplies combustion gas to the high-pressure gas turbine 10 and a low-pressure gas turbine 13 connected in series to the high-pressure gas turbine 10. I have. The low pressure gas turbine 13 is connected in series with a recuperator 18 and an exhaust gas heat exchanger 19 to an exhaust stack indicated by reference numeral 17. The combustion chamber 16 has a high-pressure compressor at its air inlet.
Air is supplied from the high-pressure compressor 11 via the recuperator 18. An adjustable connecting pipe section 20 is provided bypassing the recuperator 18 so that a portion of the exhaust gas can flow past the recuperator 18.

The high-pressure compressor 11 is arranged in series with the low-pressure compressor 14, which takes in ambient air as indicated by the arrow 21. An intermediate cooler (intercooler) 22 is provided in a connecting pipe section between the low-pressure compressor 14 and the high-pressure compressor 11, and performs heat exchange between the compressor circuit air and an external circuit for generating hot water. And the exhaust gas heat exchanger 19 is provided for the same purpose.

In the method of the present invention, the air flow is mainly controlled and the temperature level is kept constant by adjusting the speed of the low pressure compressor 14 by means of the regulator 15 to change the geometry of the low pressure gas turbine 13. Only after this possibility of control has been fully utilized is the control of the temperature of the combustion chamber begun. When this control method is employed, the efficiency in almost the full range of partial loads (10 to 100 percent load) may be about the same or even better than in the full load position. . The heat flow to the exhaust gas heat exchanger 19 increases because a portion of the exhaust gas flow passes through the adjustable connecting section 20 bypassing the recuperator 18. Therefore, the combustion chamber 16
Due to the reduced pre-heating of the air going to, the power generation for a given fuel supply will be reduced. As a result, the gas turbine unit can operate with various thermal and electrical relationships within the large range shown in FIG. The electrical efficiency decreases as the bypass amount increases, but the total efficiency still increases.

Conventional gas turbines are sensitive to ambient temperature. Power and electrical efficiency are reduced as the incoming air weight decreases as the ambient temperature increases. According to the gas turbine unit according to the present invention, the rotation speed of the low-pressure compressor 14 can be adjusted by the regulator 15 in order to change the geometry of the low-pressure gas turbine 13, thereby reducing the inflow weight of air even when the ambient temperature changes. It can be maintained at a constant value.

By injecting water into the combustion chamber as used in conventional gas turbines, nitrogen oxides (NO
x) can be reduced. Thus, usually an increase in power and a decrease in electrical efficiency and total efficiency can be obtained. However, in the gas turbine unit according to the present invention, power and electric efficiency can be improved by water injection by using an auxiliary device as shown in FIG. The water for water injection is preheated in the heat exchangers 23, 24 by compressed air and / or in the heat exchanger 25 by exhaust gas as shown in FIG. 3, and then compressed at a position upstream of the recuperator 18. Injected into the air. Therefore,
The heat absorption in the recuperator 18 increases, and the electric efficiency is improved. However, increasing exhaust losses may reduce overall efficiency.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gas turbine unit for carrying out the method of the present invention, FIG. 2 is a diagram showing an operation area of the gas turbine unit, and FIG. 3 is a configuration of a gas turbine unit having an auxiliary device for water injection. FIG. 10… High pressure gas turbine, 11… High pressure compressor, 12 …… Generator, 13 …… Low pressure gas turbine 13, 14 …… Low pressure compressor 14, 15 …… Regulator 15, 16 …… Combustion chamber, 18 …… Heaters 18, 19, 22, 23, 24, 25 ... heat exchangers, 20 ... adjustable connection pipe section.

Continuation of the front page (56) References JP-A-63-88227 (JP, A) JP-A-61-286535 (JP, A) JP-A-51-123411 (JP, A) Real opening 1986-32536 , U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F02C 3/30 F02C 9/22 F02C 7/143 F02C 3/13

Claims (4)

(57) [Claims] 1. A combustion chamber, a high pressure gas turbine driven by combustion gas from the combustion chamber, a low pressure gas turbine driven by combustion gas from the high pressure gas turbine, and driven by the low pressure gas turbine A low-pressure compressor, a high-pressure compressor arranged in series with the low-pressure compressor to supply compressed air to the combustion chamber, and driven by the high-pressure gas turbine, and driven by the high-pressure gas turbine to generate electricity A generator, a recuperator for performing heat exchange between exhaust gas and compressed air from the high-pressure compressor, an intermediate cooler for generating hot water between the low-pressure compressor and the high-pressure compressor, and generating hot water A method for operating a gas turbine unit for generating electricity and heat comprising an exhaust gas heat exchanger for Adjusting the power drawn by the generator to a desired value by changing the geometry of the low-pressure gas turbine to change the speed of the low-pressure gas turbine at a constant temperature; and the flow of exhaust gas bypassing the recuperator Adjusting the thermal power extracted by the exhaust gas heat exchanger to a desired value by controlling the temperature of the exhaust gas heat exchanger. 2. The method according to claim 1, further comprising the step of injecting water into compressed air upstream of the recuperator. 3. The method according to claim 2, further comprising the step of preheating the water to be injected. 4. A combustion chamber, a high pressure gas turbine driven by combustion gas from the combustion chamber, a low pressure gas turbine driven by combustion gas from the high pressure gas turbine and having an adjustable geometry, and the low pressure gas turbine. A low pressure compressor driven by a gas turbine, a high pressure compressor arranged in series with the low pressure compressor to supply compressed air to the combustion chamber, and driven by the high pressure gas turbine, and a high pressure compressor to generate electricity. A generator driven by a gas turbine, a recuperator for exchanging heat between exhaust gas and compressed air from the high-pressure compressor, and an intermediate for producing hot water between the low-pressure compressor and the high-pressure compressor A cooler, an exhaust gas heat exchanger for producing hot water, and the exhaust gas heat exchanger bypassing the recuperator. Gas turbine unit for generating electricity and heat consisting of Gilles adjustable connecting pipe portion.