WO1998015777A1

WO1998015777A1 - Steam power plant

Info

Publication number: WO1998015777A1
Application number: PCT/EP1997/005488
Authority: WO
Inventors: Wolfgang Henselak; Gerald Twarloh; Michael Wurm; Dennis Ham
Original assignee: Siemens Aktiengesellschaft
Priority date: 1996-10-08
Filing date: 1997-10-07
Publication date: 1998-04-16

Abstract

A steam power plant includes a steam turbine (2) for driving a generator (8) or a work-producing machine through a shaft. A feed pump configuration (5) for feeding feedwater into a steam generator (22) is incorporated into a water-steam loop. In order to drive the feed pump configuration (5) in a simple way, the feed pump configuration is driven by the shaft (7) of the steam turbine (2) that is already intended for driving the generator.

Description

STEAM POWER PLANT

Background of the Invention: Field of the Invention: The invention relates to a steam power plant having a steam turbine for driving a generator or a work-producing machine through a shaft, and a water-steam loop in which a feed pump configuration for feeding feedwater into a steam generator is incorporated.

Such a steam power plant is typically used to generate electrical energy, or to drive a work-producing machine. An operating medium, typically a water-steam mixture, that is carried in an evaporator loop of the steam turbine, is evaporated in an evaporator. The steam thus produced expands, producing work, in the steam turbine and is then delivered to a condenser. The medium condensed in the condenser is then returned to the evaporator again through a feed pump configuration. The steam turbine, combined with the condenser and a number of preheaters to make a steam turbine system, is typically disposed in a turbine hall.

A separate second steam turbine is typically provided in order to drive the feed pump configuration of a steam power plant of that kind. A partial stream of operating medium is diverted from the evaporator loop of the steam turbine which is intended for driving the generator or the work-producing machine and sent to the separate steam turbine. The partial stream that expands, producing work, in the separate steam turbine condenses in the condenser or in a second condenser assigned to the separate steam turbine. The operating medium condensed therein is returned to the evaporator loop of the first steam turbine. The separate steam turbine provided for driving the feed pump configuration is typically made significantly smaller than the steam turbine that is used, for instance, for generating energy and which drives the generator. The work-producing capacity of the separate steam turbine is typically about 3 to 5% of the work-producing capacity of the first steam turbine and thus is less by a factor of about 20 to 40 than the work-producing capacity of the first steam turbine.

A separate, electrically driven drive motor may alternatively be provided in addition in order to drive the feed pump configuration. That drive motor is supplied, for instance, with the electrical energy furnished by the generator.

However, a steam power plant with a feed pump configuration which is driven in that way is complicated and expensive, especially in the planning or installation stage.

Summary of the Invention: It is accordingly an object of the invention to provide a steam power plant, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and in which a reliable drive of a feed pump configuration is assured in a simple way.

With the foregoing and other objects in view there is provided, in accordance with the invention, a steam power plant, comprising a steam turbine having shaft; a generator or a work-producing machine to be driven by the shaft of the steam turbine; a water-steam loop connected to the steam turbine; a steam generator connected in the water-steam loop; and a feed pump configuration to be driven by the shaft of the steam turbine, the feed pump configuration being connected in the water-steam loop for feeding feedwater into the steam generator. The invention takes as its point of departure the concept that for a steam power plant which is especially simple to plan and install, the number of active components in it should be kept especially small. The number of active components in the steam power plant can be reduced, for instance by dispensing with separate drive units for components of its water-steam loop. Dispensing with a separate drive unit for the feed pump configuration is possible because the drive of the feed pump configuration is assured by the already existing steam turbine intended for driving the generator or the work-producing machine.

In accordance with another feature of the invention, a hydraulic transmission or gear is expediently connected to the turbine shaft. This is done in order to assure reliable maintaining of the planned rp and an especially reliable transmission of force from the turbine shaft to the feed pump configuration even in the case where the planned rpm of the feed pump configuration, or one of its components, differs from the planned rpm of the steam turbine.

In accordance with a further feature of the invention, the feed pump configuration includes a booster pump and a main pump located downstream of the booster pump in the water- steam loop. The term "booster pump" is used in this case in particular to mean a supplementary pump and/or an overpressure pump.

In accordance with an added feature of the invention, the shaft of the booster pump is connected to the shaft of the main pump through a step-down transmission or gear.

In accordance with a concomitant feature of the invention, the feed pump configuration is set up flush on the ground for the sake of ensuring an especially low expense for installing the steam power plant.

The advantages attained with the invention are in particular that because of the feed pump configuration, which is drivable by the turbine shaft of the steam turbine that is intended to drive the generator, no separate drive unit for the feed pump configuration is needed. Thus all of the lines and components required to operate a separate drive unit can be eliminated, such as auxiliary pressure lines and an auxiliary condenser or an auxiliary exhaust line to the main condenser, respectively, and/or electrical installations. The expense for planning and installing a steam power plant is thus especially slight. In addition, this kind of steam power plant can be modularized especially simply, and particularly when the steam turbine is set up flush on the ground, especially simple assembly of the steam power plant is possible.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a steam power plant, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. Brief Description of the Drawings:

Fig. 1 is a diagrammatic, top-plan view of one exemplary embodiment of a steam turbine system according to the invention;

Fig. 2 is a side-elevational view of the steam turbine system of Fig. 1, as seen along a line II-II of Fig. 1, in the direction of the arrows; and

Fig. 3 is a schematic and diagrammatic view of a coal-fired steam power plant with a condensate and feedwater course.

Description of the Preferred Embodiments:

Referring now in detail to the figures of the drawings, in which identical elements are identified by the same reference numerals, and first, particularly, to Fig. 1 thereof, there is seen a steam turbine system 1 which includes a steam turbine 2 with a high-pressure and medium-pressure portion 2a and a low-pressure portion 2b, to which a condenser 4 is connected radially on the downstream side. A feed pump configuration 5 shown in detail in Fig. 3 is provided on a side of the steam turbine 2 next to the condenser 4. A preheater unit 6 is disposed on a side of the steam turbine 2 facing the condenser 4. Both a generator 8 located in the vicinity of the steam turbine 2 and the feed pump configuration 5 can be driven by a shaft 7 of the steam turbine 2.

Both the high-pressure and medium-pressure portion 2a and the low-pressure portion 2b of the steam turbine 2 as well as the condenser 4 and the preheater unit 6 and the generator 8 are each constructed as a module and are moreover disposed flush with the ground. The term "module" should be understood in this case to mean a connectable, transportable component that can be pre-assembled. Each of the aforementioned modules is mounted on a sledlike structure or skid in a non-illustrated manner and can thus be shifted about especially easily.

The steam turbine system 1 is part of a coal-fired steam power plant 20 shown in Fig. 3, having a high-pressure preheater in the form of a module 9 shown in Fig. 1, which is likewise disposed flush with the ground on the side of the steam turbine 2 facing the condenser 4. The steam turbine system 1 is connected to a once-through steam generator 22 of the steam power plant 20. One such once-through steam generator is described, for instance, in co-pending U.S. Patent Application Serial No. (Attorney's Docket No. 5796) entitled "Modular Boiler", filed concurrently with the instant application and having the same assignee. The steam turbine 2, the condenser 4, the preheater unit 6, the generator 8 and the module 9 are disposed in a common power house or turbine hall 10.

The generator 8 is connected through an electrical supply line system 11, into which a switch system 12 is incorporated, to a generator transformer 13 that is disposed outside the turbine hall 10 and serves to transform electrical voltage furnished by the generator 8 to a higher level .

Fig. 2 is a side view of the turbine hall 10, showing the disposition of the steam turbine 2, the condenser 4 and the preheater unit 6 flush with the floor. The condenser 4 is radially connected to the steam turbine 2 on the downstream side. The condenser 4, being constructed as a module, includes a first condenser element 4a and a second condenser element 4b located above the first. An especially space- saving, compact construction is thus achieved. The preheater unit 6, being also constructed as a module, includes a number of preheater elements 15 disposed in a common support stand or heater rig 14. Each preheater element 15 can be acted upon with bled steam A from the steam turbine 2 through a bled steam duct system 16. The pressure and temperature of the bled steam A are functions of the location, wherever it is, at which the steam turbine 2 is bled. Each preheater element 15 is constructed for a specific pressure range of the bled steam A. Placing the preheater elements 15 in the common heater rig 14 makes it possible to prefabricate the preheater unit 6 as a module. This makes the effort and expense of on-site assembly especially low. In order to facilitate assembly of the steam turbine system 1 even further, the module 9 is also mounted on a sled structure or skid.

As is shown schematically in Fig. 3, the steam turbine 2 of the steam power plant 20 is connected to the once-through steam generator 22 through a water-steam loop 24. The steam turbine 2 is followed by the condenser 4, which in turn communicates on the outlet side through a condensate pump 26 and the preheater unit 6 with a feedwater tank 28. In order to feed feedwater W from the feedwater tank 28 into the once- through steam generator 22, which is connected on the outlet side to the steam turbine 2, the feed pump configuration 5 is incorporated into the water-steam loop 24 of the steam turbine 2.

The feed pump configuration 5, which is drivable by the shaft 7 of the steam turbine 2, includes a main pump 5a and a supplementary or booster pump 5b preceding the main pump in the water-steam loop 24.

In the exemplary embodiment, a hydraulic transmission or gear 30 is connected to the shaft 7 of the steam turbine 2 for the sake of force transmission to the main pump 5a. The main pump 5a is in turn connected through a step-down transmission or gear 32 to the booster pump 5b. The individual shafts which are rotating at different speeds are designated by reference numerals 7, 27 and 37.

In the exemplary embodiment, the feed pump configuration 5 is on the "hot end" , that is on the opposite end of the shaft 7 of the steam turbine 2, from the generator 8. However, it may also be disposed on the "cold end" of the shaft 7 of the steam turbine 2, or in other words on the same end as the generator 8. Instead of driving a consumer in the form of the generator 8, the shaft 7 may drive a consumer in the form of a work-producing machine 8'. It is possible, as shown in the exemplary embodiment, for only one feed pump configuration 5 to be driven by the shaft 7 of the steam turbine 2. Alternatively, however, a plurality of feed pump configurations may be drivable by the shaft 7 of the steam turbine 2.

Claims

We claim :

1. A steam power plant, comprising:

a steam turbine having shaft;

a generator or a work-producing machine to be driven by said shaft of said steam turbine;

a water-steam loop connected to said steam turbine;

a steam generator connected in said water-steam loop; and

a feed pump configuration to be driven by said shaft of said steam turbine, said feed pump configuration being connected in said water-steam loop for feeding feedwater into said steam generator.

2. The steam power plant according to claim 1, including a hydraulic transmission connected to said shaft of said steam turbine for force transmission.

3. The steam power plant according to claim 1, wherein said feed pump configuration includes a main pump and a booster pump preceding said main pump in said water-steam loop.

4. The steam power plant according to claim 3, wherein said main pump and said booster pump have shafts, and including a step-down transmission connecting said shaft of said booster pump to said shaft of said main pump.

5. The steam power plant according to claim 1, wherein said feed pump configuration is disposed flush with the ground.