JPS5874809A - Coaxial combined plant - Google Patents

Abstract

PURPOSE:To make it possible to easily carry out maintenance and management of a generator by disposing rotary bodies of the main engine of the titled plant into an arrangement in which a gas and steam turbines are provided on one side of the generator and rigid couplings are used in coupling rotary bodies respectively. CONSTITUTION:In the titled palnt, a generator E1, a gas turbine GT and a steam turbine ST3 which are rotary bodies of the main engine in the order of GT2-ST3-E1 or ST3-ST2-E1. Further, the generator E1 is coupled to a starting device 8 through a slip ring 10. A thrust bearing 4 is installed in the shaft system between the turbines GT2 and ST3, while the respective rotary systems 1-3 are coupled by rigid couplings 9. By this arrangement, at the time of maintenance and inspection of the generator E1, particularly at the time of drawing out the rotor, the operation is carried out without dismantling the turbines GT2 and ST3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coaxial combined plant, particularly to an arrangement system of a generator, a gar turbine, and a steam turbine, which are the main rotating bodies of the coaxial combined plant.

Figure 1 shows a conventional main engine rotating body arrangement system, in which a generator 1 is installed in the center, and gas turbines 2 and steam turbines 3 are installed on both sides of the generator 1, so-called C (gas 11-hi)-G
(from the start) -8 (steam turbine) arrangement.

Such a conventional CG-8 arrangement method has drawbacks such as first order.

(1) During maintenance and inspection of the generator (when removing the rotor at IJI!j).

It is necessary to disassemble the steam or gas turbine.

Furthermore, depending on the barn, it may be necessary to jack up the stator of the generator, which lengthens the period for overhaul inspection.

(2) Since the generator is located between the steam turbine and the gas turbine, the space for drawing out the stator lead wires of each generator extends laterally, requiring a larger installation surface area. In plants with a turbine or gas turbine alone, it was possible to use the generator foundation work space and pull it out in the axial direction).

(3) It is necessary to install a thrust bearing 4 in each of the steam turbine and the gas turbine. Therefore, a flexible coupling 5 is installed between the thrust bearings 4 to absorb the movement of the shaft positions of the rotors and the difference in thermal expansion. It is necessary to install it.

But what about this flexible coupling?

Compared to rigid couplings, this is unfavorable in terms of vibration characteristics of the shaft system, and is a cause for concern in improving the reliability of the shaft system.

In Fig. 1, %6 is the turbine section of the gas turbine 2, 7 is the compressor section thereof, 8 is the starting device, 9 is the rigid coupling, and 10 is the slip ring, which is connected to the generator excitation current. This is to supply power from an external power source.

The present invention has been devised to overcome one or more of the disadvantages of the prior art and is an improvement over the conventional C-G-8 arrangement in coaxial combined plants.

The present invention arranges the main rotors of a coaxial combined plant in the order of a gas turbine, a steam turbine, and a generator, or in the order of a steam turbine, a gas turbine, and a generator, and in a shaft system between the gas turbine and the steam turbine. It is characterized by the installation of thrust bearings and the use of rigid couplings for all connections between the rotating bodies.

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

In Fig. 2, 1 is a generator, 2 is a gas turbine, 3 is a steam turbine, 4 is a thrust bearing, 6 is a turbine section of the gas turbine, 7 is a compressor section thereof, 8 is a starting device, and 9 is a rigid coupling. , 10 is a slip ring, and the main rotating bodies of the coaxial combined graft are arranged in the order of gas turbine 2, steam turbine 3, and generator 1, so-called C-8.
-G arrangement method. In addition, as a modification of this, the gas turbine 2 and the steam turbine 3 are replaced, and the 5-C-G
An array method may also be used.

By adopting this type of C-8-Q or S-C-G arrangement, the generator is located at the end of the shaft system, so the electrical system and steam system are separated in terms of layout. I can do it again 1
The thrust bearings 4 are connected to the gas turbine 2 and the steam turbine 3.
All the rotating bodies can be connected by rigid couplings 9 by simply installing them in the shaft system between them.

In other words, in a coaxial combined plant, all 4!
The Il-based thrust force includes the thrust force of the gas turbine 2 and the steam turbine 3, but C-8-G or 5-C-
If the direction of action of the gas turbine thrust force and the direction of action of the steam turbine thrust force are mutually canceled in a G arrangement and the two thrust forces are balanced, the thrust bearing 4 can be used for the gas turbine 2 and the steam turbine 3. This thrust bearing is installed only on the shaft system between the Since it can be made sufficiently small, the thrust bearing can be shared.This eliminates the need to install a thrust bearing in each of the gas turbine and steam turbine.

Therefore, there is no need to provide a flexible coupling, and the rotating bodies can all be connected by rigid couplings.

Therefore, in FIG. 2, the thrust bearing 4 is connected to the shaft system between the gas turbine 2 and the steam turbine 3 (
The rotary bodies l are installed between the second bearing 11 and the third bearing 12).

Since all of the connections in 2.3 are performed by rigid couplings 9, each rotor thermally expands to the right from the thrust bearing 4 during operation under pressure after being connected.

In other words, since the single chamber of the gas turbine 2 is fixed to the foundation near the thrust bearing 4, thermal expansion occurs to the left from this point, so thermal expansion between the single chamber of the gas turbine and the rotor is not a problem. (This can be absorbed. - This is because the single chamber of the steam turbine 2 is also fixed to the foundation near this thrust bearing.

Since the thermal expansion starts from this point to the right, the thermal expansion of the single chamber of the steam turbine and the rotor are in the same direction, and the difference in thermal expansion can be easily absorbed.

Note that instead of installing the thrust bearing 4 in the shaft system between the gas turbine 2 and the steam turbine 3, it is installed in the shaft system between the steam turbine 3 and the generator l.

Since the amount of thermal expansion of the rotor in the gas turbine increases (because the thermal expansion of the steam turbine section is added to the thermal expansion of the rotor), there is a possibility that it will come into contact with the casing, and there is a possibility that the rotor will come into contact with the casing. If the gap between the chamber and the rotor is large, there is a problem that the performance will deteriorate significantly, so this method cannot be adopted.

As described above, according to the present invention, the main rotating bodies of a coaxial combined are arranged in the order of gas turbine, steam turbine, and generator (C-8-G arrangement) or in the order of steam turbine, gas turbine, and generator. (S-C-G arrangement) allows maintenance and inspection of the generator (particularly removing the rotor) to be performed without disassembling the other main rotating bodies, making it easier than before. Since the system and the steam system can be separated in terms of layout, the space required for the overall layout of the coaxial combined plant can be reduced, and the layout (especially drawing out the stator lead wires of the generator) becomes easier.

Moreover, by adopting such a C-5-G or 5-C-G arrangement, it is possible to install only one thrust bearing in the entire shaft system, that is, to install the thrust bearing in the shaft between the gas turbine and the steam turbine. By simply installing it in the shaft system, all rotating bodies can be connected using rigid couplings.Therefore, there is no need to use conventional flexible couplings, which improves reliability regarding shaft system vibration. It can be measured.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an arrangement method of main engine rotating bodies in a conventional coaxial combined plant, and FIG. 2 is a diagram showing an example of an arrangement method of main engine rotating bodies in a coaxial combined plant according to the present invention. l... Generator, 2... Gas turbine 1.3... Steam turbine, 4... Thrust bearing, 9... Rigid coupling.

Claims (1)

[Claims] The main engine rotating bodies are arranged in the order of gas turbine, steam turbine, and generator, or in the order of steam turbine, gas turbine, and generator, and a thrust bearing is installed in the shaft system between the gas turbine and the steam turbine, and each rotation A coaxial combined 7° runt characterized by all body connections being rigid couplings.