FI102692B - Methods of operation of a gas turbine plant for simultaneous production of electricity electricity and heat and gas turbine plant for the practice of the method - Google Patents

Description

χ 102692

The invention relates to a method for operating a gas turbine apparatus for the simultaneous production of electricity and heat. The invention relates to a method for using a gas turbine apparatus for the simultaneous production of electricity and heat.

A gas turbine plant for the simultaneous production of electricity and heat, for example as hot water for a district heating network, so-called. as thermal power, the following requirements are set: - high electrical efficiency - high overall thermal efficiency - high electrical / thermal efficiency 15 - flexibility between electricity and heat production - excellent partial load characteristics - insensitivity to ambient temperature variations.

These requirements are highly met well on a type of two-axle gas turbine plant, which 20 comprises the production of the combustion chamber, the combustion chamber of gas used by the high-pressure turbine and the high pressure turbine exhaust gas used by the low-pressure turbine, a low pressure turbine used by the low-pressure compressor and with the series-connected high-pressure turbine used by the high-pressure compressor PAI-25 neenalaisen for supplying air to the combustion chamber, the high pressure turbine used by the generator of electricity , a recuperator for exchanging heat between the exhaust gases and the compressor air, and an intercooler between low and high pressure compressors and an exhaust heat exchanger, both for hot water heating.

The electricity is generated by a generator coupled to the shaft of the high pressure turbine while producing hot water of 70-120 ° C in the intercooler and exhaust heat exchanger. Thus, the shaft of the high pressure turbine rotates at rpm to 35 rpm while the axis of the low pressure turbine is free to rotate.

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The thermodynamic process in such a gas turbine apparatus can be briefly called "intercooled recuperative exhaust gas turbine" and has a 30-40% better electrical efficiency than a simple gas turbine with a similar turbine inlet temperature. By using the heat of the intercooler and the exhaust gas to produce hot water, a high overall efficiency is achieved.

The prior art is disclosed in EP-A-247984, EP-A-150990 and GB-A-836135. appear in the emblem-15 kit. Other embodiments of the invention are apparent from the appended claims 2 to 4.

The invention also relates to a gas turbine apparatus for carrying out the process of the invention.

For a more detailed description of the invention, reference is made to the accompanying drawings, in which Figure 1 is a schematic diagram of a gas turbine apparatus for carrying out the method of the present invention, Figure 2 is a diagram showing a gas turbine apparatus operating area;

Referring to FIG. and a regulator 15 for a variable low pressure turbine geometry is fitted to the low pressure turbine.

3, 102692

The combustion chamber 16 (boiler) is connected at its gas outlet to a high pressure turbine to supply gas and a low pressure turbine connected in series therewith. The low pressure turbine is connected to a chimney marked with arrow 17, in series with recuperator 18 and exhaust gas heat exchanger 19. The combustion chamber, by its air intake, is connected to a high pressure compressor with its chunks for feeding through the recuperator. The adjustable bypass connection 20 is arranged to pass a portion of the exhaust stream 10 past the recuperator 18.

The high pressure compressor is connected in series with the low pressure compressor which draws in air from the environment as indicated by arrow 21. The intercooler 22 is arranged to communicate between the low pressure compressor and the high pressure compressor 15 to exchange heat between the compressor circuit air and external circuit for hot water an exhaust gas heat exchanger 19 is used.

In the method of the invention, the air flow is controlled first and foremost, while the temperature level is kept constant by changing the rotational speed of the low pressure compressor by means of the device 15 to change the geometry of the low pressure turbine. Only when this control option has been fully utilized will the furnace temperature control be changed.

'25 The efficiency of this adjustment method will be as good as, if not better than, the full load point in almost the entire partial load range (10-100% load). By passing a portion of the exhaust gas stream past recuperator 18 through an adjustable bypass connection 20, heat flow to the exhaust gas heat exchanger 19 is increased, thereby reducing power generation by constant fuel supply due to reduced preheating of the combustion air. The gas turbine apparatus can thus operate over a wide range of electrical / thermal ratios, as illustrated in Figure 2. As the bypass ratio increases, the pie-35 reduces the electrical efficiency while the overall efficiency increases.

4, 102692

A conventional gas turbine is sensitive to ambient temperatures. The output power and electrical efficiency decrease as the ambient temperature rises and the mass flow of inlet air decreases. In the gas turbine apparatus 5 described herein, the RPM of the low pressure turbine can be adjusted by means of the device 15 to change the geometry of the low pressure turbine so that the air mass flow is kept constant as the ambient temperature fluctuates.

As with conventional gas turbines, the amount of nitrogen oxides (N0X) in the exhaust gas can be reduced to a low level by injecting air into the combustion chamber. This usually results in increased electrical power and reduced electrical and overall efficiency. However, in the gas turbine apparatus described herein, electrical power and electrical efficiency can be increased by water injection using the auxiliary apparatus shown in Figure 3. Water for water injection is preheated by compressor air in heat exchangers 23 and 24 and / or by exhaust gas in heat exchanger 20, as shown. 3, then to be injected into the compressor air before the recuperator 18 at position 26. Thereby, the heat output from the recuperator increases with the resulting improved electrical efficiency. However, the overall efficiency decreases as the chimney losses increase.

Claims (4)

A method of operating a gas turbine apparatus for the simultaneous generation of electricity and heat comprising 5 combustion chambers (16), a high pressure turbine (10) operated by a gas turbine (10) and a high pressure turbine (13) operated by a low pressure turbine and ? -10 for supplying air under pressure to the combustion chamber of the necompressor (11), for generating electricity for the generator (12) used by the high pressure turbine, for heat exchange between the exhaust gases of the recuperator (18) and the low and high pressure compressors (19) ), both for hot water heating, characterized in that the desired electrical power is adjusted by changing the geometry of the low pressure turbine to change the rotational speed of the low pressure turbine with a constant 20 and that the desired thermal power is adjusted by adjusting the bypass flow past the recuperator. Method according to claim 1, characterized in that water is injected into the compressor air before the recuperator. Method according to claim 2, characterized in that the injection water is preheated. A gas turbine apparatus for carrying out the method of any one of claims 1 to 3, comprising: a combustion chamber (16), a high pressure turbine (10) used by the gas of the combustion chamber and a low pressure turbine (14) operated by a low pressure turbine and -35 for supplying air under pressure to 102692 6 combustion chambers, generating electricity for the high pressure turbine generator (12), for exchanging exhaust gas with compressor air in the recuperator (18), and for the low and high pressure intercooler (22) of the intercooler (22) 19), both for hot water heating, characterized in that the low pressure turbine (13) is arranged to be of variable geometry and that an adjustable bypass connection (20) is arranged past the recuperator (18). 7 102692