JPS63118501A - Exhaust heat recovery device for gas turbine - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to exhaust heat recovery equipment for gas turbines.

[Prior art]

A conventional gas turbine exhaust heat recovery facility is configured as shown in FIG. That is, the gas turbine 1 has an air intake duct 1
Air is taken in through duct 1, and exhaust gas is discharged through exhaust duct 7 while generating a predetermined amount of power. During steady operation, this exhaust gas is led to the exhaust heat recovery equipment 2 via the exhaust gas intake duct 8, where heat is recovered, and the final exhaust gas is released into the atmosphere via the exhaust gas duct 10 and the chimney 3.

Here, if the exhaust heat port installation @ 2 is a naphtha cracking furnace and there is a restriction on the amount of exhaust gas taken in, the amount of exhaust gas of the gas turbine 1 and the amount of gas required by the naphtha cracking furnace need to match.

That is, in FIG. 3, it is sufficient that the naphtha cracking furnace can be operated with the exhaust gas amount a corresponding to the maximum point C of the gas turbine power generation efficiency, but the required gas amount of the naphtha cracking furnace and the exhaust gas of the gas turbine may be adjusted accordingly. The quantities do not match.

On the other hand, gas turbines are products that can be economically produced through limited edition models and mass production, so we design and manufacture gas turbines that can generate maximum efficiency according to the amount of exhaust gas required by the naphtha cracking furnace. However, there is something to be said for its economic efficiency.

Therefore, in general, the required exhaust gas iib of the naphtha cracking furnace is
If the gas turbine maximum efficiency exhaust gas amount a does not match, as shown in Figure 3, take measures such as narrowing down the damper 6 so that the gas turbine exhaust gas amount becomes b to match the exhaust gas amount required by the naphtha cracking furnace. ing. However, in this case, the gas turbine 1 operates at a partial load, so there is a drawback that the gas turbine 1 must be operated at a partial load efficiency d lower than the maximum efficiency C.

On the other hand, when the exhaust heat recovery equipment 2 is a naphtha cracking furnace, as shown in FIG. There is.

In such a case, a bypass chimney 4 as shown in FIG. 2 is required. Moreover, since the gas turbine exhaust gas in this bypass chimney 4 is usually at a high temperature of 350°C to 600°C, it is necessary to select a material and structure that can withstand this temperature. Because it is difficult to share the bypass chimney with the existing bypass chimney, the installer has no choice but to establish an independent bypass chimney, which places a heavy financial burden on the installer.

[Purpose of the invention]

The present invention has been made to solve the above drawbacks,
The purpose of this is to enable the gas turbine to operate with maximum power generation efficiency during normal operation, and to enable high-temperature exhaust gas heat-resistant bypass chimneys to be used when starting up the gas turbine, or when gradually supplying exhaust gas to the exhaust heat recovery equipment. The goal is to make it unnecessary.

[Structure of the invention]

The gas turbine exhaust heat recovery equipment of the present invention that can achieve the above object includes a main exhaust heat recovery equipment, a auxiliary exhaust heat recovery equipment whose gas flow is parallel to the cough main exhaust heat recovery equipment, and a bypass line. , and a control damper that controls the gas flow rate supplied to each of them is adjusted by a command from a controller of the main exhaust heat recovery equipment.

The above-mentioned main exhaust heat recovery equipment corresponds to equipment such as a naphtha cracking furnace, which has restrictions on the amount of exhaust gas intake. Further, the auxiliary exhaust heat recovery equipment includes, for example, a steam boiler.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of the exhaust heat recovery equipment for a gas turbine according to the present invention, in which the gas turbine 1 has an air intake duct 11
After the fresh air is taken in through the duct 7 and a predetermined amount of power is generated, the exhaust gas is discharged through the exhaust duct 7. This exhaust duct 7
Exhaust gas is taken into the main exhaust heat recovery equipment 2 through an exhaust gas intake duct 8 connected to the The necessary exhaust gas is taken into the main exhaust heat recovery equipment 2 by adjusting the opening degree of the main exhaust heat recovery equipment introduction rod damper 6.

On the other hand, the excess exhaust gas is led to the auxiliary exhaust heat recovery equipment 20 installed in parallel with the main exhaust heat recovery equipment 2 through the auxiliary exhaust heat recovery equipment introduction duct 15 connected to the exhaust duct 7. In the middle of this inlet duct 15, there is a sub-exhaust heat recovery equipment rotor damper 13.
is provided, and its opening and closing are performed by the inlet damper controller 21. In this way, by introducing the surplus exhaust gas into the auxiliary exhaust heat recovery equipment 20, the gas turbine l always maintains the exhaust gas suitable for the highest efficiency in FIG. It becomes possible to operate while discharging a.

The exhaust gas discharged from the main exhaust heat recovery equipment 2 is discharged into the atmosphere from the chimney 3 through the exhaust gas discharge duct 10.

Similarly, the exhaust gas discharged from the auxiliary exhaust heat recovery equipment 20 is discharged from the chimney 3 through the auxiliary exhaust heat recovery equipment outlet duct 17, the mixing duct 18, and the exhaust gas exhaust duct 10.

A bypass duct 23 is provided in parallel to the auxiliary exhaust heat recovery equipment 20. This bypass duct 23 is composed of a bypass inlet duct 14 and a bypass outlet duct 16, which are connected via a bypass damper 12. The bypass inlet duct 14 is connected to the exhaust duct 7, and the bypass outlet duct 16 is connected to the mixing duct 18. do.

Gas turbine exhaust gas generally has a temperature of 350°C to 600°C.
When starting the gas turbine 1 due to the high temperature of about C,
The main exhaust heat recovery equipment rotor damper 6 is fully closed, and the bypass damper 12 and the auxiliary exhaust heat recovery equipment rotor damper 13 are operated by the inlet damper controller 21 to introduce the exhaust gas into the auxiliary exhaust heat recovery equipment 20 and the bypass duct 23. . The gas turbine exhaust gas that has passed through the bypass duct 23 is discharged into the mixing duct 18 with almost no temperature drop, but the exhaust gas is mixed in the mixing duct 18 with heat recovered by the auxiliary exhaust heat recovery equipment 20 and the exhaust gas whose temperature has been reduced. The temperature becomes lower than the heat resistance temperature of the chimney 3. Therefore, the exhaust gas in the mixing duct 18 can be introduced into a conventional conventional chimney 3, eliminating the need for a high temperature resistant bypass chimney 4 for the gas turbine.

Note that when a steam boiler is installed as the secondary exhaust heat recovery equipment, a secondary effect of reducing NOx in the exhaust gas of the gas turbine 1 can also be expected by guiding the generated steam to the combustor of the gas turbine through the steam pipe 19.

〔Effect of the invention〕

As described above, according to the present invention, during normal operation of a gas turbine, it is possible to operate the gas turbine while maintaining its power generation efficiency at the highest efficiency.

On the other hand, the high-temperature heat-resistant bypass chimney becomes unnecessary when starting up the gas turbine or when gradually supplying exhaust gas to the exhaust heat recovery equipment.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the gas turbine exhaust heat recovery equipment according to the present invention, Figure 2 is a schematic diagram of the conventional gas turbine exhaust heat recovery equipment, Figure 3 is an efficiency diagram of the gas turbine, and Figure 4 is the cracking furnace. FIG. 3 is a mode diagram of gas turbine exhaust gas intake into the gas turbine. 2... Main exhaust heat recovery equipment, 6, 12. 13... Damper, 20... Sub-exhaust heat recovery equipment, 22... Controller of main exhaust heat recovery equipment. Figure 3 Figure 4

Claims (1)

[Claims] A side exhaust heat recovery equipment and a bypass line are installed in parallel with the main exhaust heat recovery equipment, and the gas flow is parallel to the main exhaust heat recovery equipment,
An exhaust heat recovery device for a gas turbine, characterized in that a control damper that controls the flow rate of gas supplied to each of the devices is adjusted by a command from a controller of the main exhaust heat recovery facility.