WO2007113017A1

WO2007113017A1 - Steam turbine installation and associated operating method

Info

Publication number: WO2007113017A1
Application number: PCT/EP2007/050730
Authority: WO
Inventors: Ralf Greim; Timothy Stephen Rice
Original assignee: Alstom Technology Ltd
Priority date: 2006-03-31
Filing date: 2007-01-25
Publication date: 2007-10-11
Also published as: CN101415907A; DE112007000718A5; US20090031726A1

Abstract

The invention relates to a steam turbine installation (1), in particular for generating electricity, comprising a steam path (2), which contains a steam generator (4) and a steam turbine (3). To reduce the risk of erosion of the components that are situated in the steam path (2), such as the blades of the steam turbine (3), an inertial separator (6) is located in the steam path (2) between the steam generator (4) and the steam turbine (3).

Description

Steam turbine plant and associated operating method

Technical area

The invention relates to a steam turbine plant, in particular for power generation, with the features of the preamble of claim 1.

The invention also relates to a method for operating such a steam turbine plant. Furthermore, the invention relates to a use of an inertial separator.

State of the art

From CH 653 097 A5 a combined gas turbine steam power plant for power generation is known. Such a combination plant comprises on the one hand a gas turbine with associated compressor and associated combustion chamber and on the other hand, a steam turbine with associated steam generator. The steam generator is heated with the hot exhaust gases of the gas turbine.

In the known combination plant, the combustion chamber is equipped with a fluidized bed. The exhaust gases or flue gases generated during operation are loaded with particles. In order to avoid an entry of these particles into the gas turbine, a plurality of cyclone separators are arranged in the exhaust path upstream of the gas turbine.

From DE 198 34 376 A1 a gas turbine plant is known in which guide vanes are cooled with a cooling gas. In order to eliminate dust from the cooling gas, an axial cyclone is arranged in the cooling gas path upstream of the guide vanes to be cooled. In modern steam turbine plants, there is a trend to increase the steam temperature and vapor pressure at the inlet of the steam turbine to thereby achieve higher efficiencies. With inlet temperatures of 580 ⁰ C to 600 ⁰ C these steam turbines no longer work supercritical or supercritical, but already ultra-supercritical. Newer steam turbine plants tend to even higher inlet temperatures of 620 ° C to 650 ⁰ C. For future plants even inlet temperatures of 700 ° C to 720 ° C are considered. It has been found that the oxidation of the steam-carrying components, eg of the steam generator, increases disproportionately at these high steam temperatures. This results in oxide particles that detach and are entrained by the vapor flow. The particles thus enter the steam turbine, but there they can not follow the deflections of the steam flow on the blades due to inertia, whereby they impinge on guide vanes and rotor blades. At the prevailing high speeds, erosion occurs on the blades. Such erosion affects the aerodynamics of the blades, resulting in a reduction in the efficiency of the steam turbine.

Presentation of the invention

The invention aims to remedy this situation. The invention, as characterized in the claims, deals with the problem of finding a way for a steam turbine plant of the type mentioned, which reduces in particular the risk of erosion of the blades of the steam turbine by oxide particles.

According to the invention, this problem is solved by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea that in the steam path leading from the steam generator to the steam turbine upstream of the steam turbine, the steam entrainment To remove th particles from the steam flow, preferably by means of an inertial separator.

The use of an inertial separator, which can be configured in particular as a cyclone separator, is a relatively inexpensive implementable measure which is distinguished from the use of conventional filters by a comparatively low pressure loss. In addition, the use of an inertial separator is significantly less expensive than the use of high purity water to reduce the oxidizing effect of the steam or the use of particularly high quality steam generator materials to increase the oxidation resistance of these components or the use of particularly high quality alloys or coatings or surface treatments of the blades to improve the erosion resistance of the blades. In comparison to the alternatives mentioned, the inertial separator is thus characterized by an extremely low pressure loss and by a low-cost feasibility. An inertial separator is characterized by the fact that a flow deflection is forced in it which the entrained particles can not follow because of their larger mass. The particles hit corresponding obstacles instead, which slows them down.

Other important features and advantages of the present invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

Brief description of the drawings

A preferred embodiment of the invention is illustrated in the drawings and will be explained in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components. Show, in each case schematically, Fig. 1 is a greatly simplified schematic diagram of a schematic

Steam turbine plant,

2 is a partially sectioned simplified side view of an inertial separator,

Fig. 3 is a partially cutaway perspective view of another

Inertia.

Ways to carry out the invention

According to FIG. 1, a steam turbine plant 1 according to the invention comprises a steam path 2, in which a steam turbine 3 and a steam generator 4 are arranged. In this case, the steam turbine 3 is downstream of the steam generator 4 and can, for example, drive a generator 5, so that the steam turbine plant 1 is preferably used to generate electricity. The steam turbine 1 may be part of a combined system, so a combined gas turbine steam power plant. In particular, then the steam generator 4 can be heated with hot exhaust gases of the gas turbine. Basically, however, the heating of the steam generator 4 is configured arbitrarily.

According to the invention, an inertial separator 6 is arranged in the vapor path 2 downstream of the steam generator 4 and upstream of the steam turbine 3. The inertial separator 6 serves to eliminate entrained particles in the vapor flow, that is to say solids, as a rule, which takes place by means of inertial forces. The precipitated particles can be removed from the inertial separator 6 in accordance with an arrow 7.

In the case of steam turbine plants 1 with several passes through the steam generator 4, so-called reheating, which are typically customary today both upstream of the high-pressure and the medium-pressure turbine cylinder, it is possible to use be assigned to the passage of such an inertial separator. In principle, each steam outlet from the steam generator 4 can be equipped with such an inertia separator 6.

2 and 3, the inertial separator 6 may preferably be configured as a cyclone separator, which is characterized in that the vapor flow, represented in FIG. 2 by arrows 8, rotates about a longitudinal central axis 9 of the inertial separator 6. The cyclone separator will also be referred to as 6 below. Other designs, such as Electrostatic filters are also possible, so that the cyclone separator 6 mentioned here is given by way of example only and without restriction of generality.

In the embodiment shown in Fig. 2, the cyclone separator 6 is preferably arranged in the installed state upright, whereby its longitudinal central axis 9 extends substantially vertically. The cyclone separator 6 has two sections in the vertical direction, namely an upper cylinder section 10 and a lower cone section 11. The cone section 11 adjoins the cylinder section 10 at the bottom and tapers with increasing distance from the cylinder section 10, that is to say downwards.

The cyclone separator 6 is integrated into the steam path 2 via a steam inlet 12 and a steam outlet 13. In the preferred embodiment shown here, the steam inlet 12 is connected tangentially to the cyclone separator 6 or to its cylinder section 10. As a result, the desired vortex flow with respect to the longitudinal central axis 9 is already enforced when flowing into the cyclone separator 6. Such a vortex flow generates strong centrifugal forces. Due to their increased mass inertia, entrained particles are thrown against the wall of the cyclone separator 6, as a result of which the particles can be strongly decelerated and, secondly, also comminuted. The deceleration of the particles causes them to fall due to gravity easier down in the cone section 11. The fragmentation of the particles has the advantage that particles which, despite the strong separation effect of the Zy- klonabscheiders 6 leave the cyclone 6 again with the steam flow 8, represent in the steam turbine 3 for the blades only a reduced risk of erosion.

Due to the central vortex in the cyclone separator 6, a centrifugal field is created in the latter in which particles of greater mass or greater specific gravity are carried to the outside. Outside is then the wall contact with the above consequences. In order to improve the fragmentation effect on impact of the particles on the wall of the cyclone separator 6, the wall can be designed accordingly. Furthermore, the wall of the cyclone separator 6 can preferably be designed specifically in the cylinder section 10 so that particles which move along the wall can not reach the steam outlet 13. For example, the wall includes not shown radially inwardly projecting annular obstacles. Optionally or alternatively, it is also possible to charge the respective wall electrostatically or electrodynamically, which also makes it possible to "capture" particles on the wall.

The cone section 11 serves as a collecting container for separated particles. From the cone section 11, the precipitated particles can be removed according to the arrow 7. This is basically possible during operation of the steam turbine plant 1, since the steam flow operates at relatively high pressures. By cyclically opening a corresponding Ausblasventils, not shown here, which controls an outlet opening 14 of the cone portion 11, the deposited particles can be discharged. It is also possible to use standstill times of the steam turbine plant 1 for removing the precipitated particles from the cone section 11.

In the embodiment shown here, the steam outlet 13 is connected tangentially to the cyclone separator 6 or to its cylinder section 10. This tangential connection, which is also oriented in the direction of rotation of the vortex flow, reduces the flow resistance or the pressure drop during the flow through the cyclone separator 6. Thus, the entrained particles the cyclone separators 6 can not flow unhindered, the two tangentially arranged connections, namely steam inlet 12 and steam outlet 13 are spaced apart from each other in the axial direction. Preferred here is the arrangement shown here, in which the steam inlet 12 is arranged in a lower end region of the cylinder section 10, while the steam outlet 13 is arranged in an upper end region of the cylinder section 10. To get from the lower end to the upper end, the entrained particles would have to move upwards against gravity, which is not the case in the rule.

In contrast to the illustrated embodiment, it is also possible in principle, the steam outlet 13 again tangentially, but with respect to the direction of rotation to arrange in opposite directions. Likewise, the steam outlet 13 may be radially oriented with respect to the longitudinal central axis 9. Furthermore, it is in principle possible to arrange the steam outlet 13 axially and with respect to the longitudinal central axis 9 centrally. The latter variant shows the largest separation effect.

The inertial separator 6 is adapted to the particular operating conditions of the steam turbine plant 1. For this purpose, the inertial separator 6 is preferably designed so that it can operate at a vapor pressure between 250 bar and 350 bar. Furthermore, the inertial separator 6 is designed for steam temperatures in the range of 620 ° to 720 °. The dimensioning of the inertial separator 6 is selected, for example, so that a quantity of steam which is required to produce a steam turbine output of about 1000 MW can be more or less cleaned of particles. For example, the inertial separator 6 is designed so that particles with a particle size between 0.1 mm and 0.5 mm can be eliminated from the vapor. The choice of material for the production of the inertial separator 6 is expedient to be chosen so that it is suitable for the precipitation of oxide particles, such as magnetite or spinel. Furthermore, the inertial separator 6 should have a service life of at least 50,000 hours, but preferably 100,000 hours to 200,000 hours. According to FIG. 3, the inertial separator 6 designed as a cyclone separator 6 may, in another embodiment, have a spherical or spherical housing 15, which can be made particularly pressure-resistant to a particular degree. The steam inlet 12 may also be connected tangentially to the housing 15 here. Preferably, the connection of the steam inlet 12 to the housing 15 in an equatorial plane 16 of the housing 15. In the preferred vertical arrangement of the cyclone 6 and the housing 15, the equatorial plane 16 extends substantially horizontally.

The steam outlet 13 is preferably arranged at the top of the housing 15, in particular coaxially to the longitudinal central axis 9 of the housing 15. The longitudinal center axes of the spherical housing 15 characterized in that they all extend through the unspecified center of the housing 15. When the housing 15, the steam outlet 13 associated longitudinal central axis 9 extends substantially vertically. In the preferred embodiment shown here, the longitudinal central axis 9 assigned to the steam outlet 13 is perpendicular to the aforementioned equatorial plane 16 assigned to the steam inlet 12.

The outlet opening 14 is preferably located at the lower end of the housing 15 in the standing arrangement of the housing 15. In the preferred embodiment shown, the outlet opening 14 is arranged coaxially to a longitudinal center axis 9 'of the housing 15 on the housing 15. In the present embodiment, the longitudinal central axis 9 'associated with the outlet opening 14 is arranged coaxially with the longitudinal central axis 9 assigned to the steam outlet 13, ie, the two longitudinal central axes 9 and 9' coincide. Thus, in the present case, the longitudinal center axis 9 'associated with the outlet opening 14 is also perpendicular to the equatorial plane 16 and extends substantially vertically. LIST OF REFERENCE NUMBERS

steam turbine plant

vapor path

steam turbine

steam generator

generator

Inertia separator / cyclone separator separated particles

Steam flow, 9 'longitudinal center axis of 6

Cylinder section of 6

Cone section of 6

steam inlet

steam outlet

Outlet opening of 11 or 15

casing

equatorial plane

Claims

claims

1. steam turbine plant, in particular for power generation, with a steam path (2), in which a steam generator (4) and downstream of a steam turbine (3) are arranged, characterized in that in the steam path (2) between the steam generator (4) and the Steam turbine (3) at least one inertial separator (6) is arranged.

2. Steam turbine plant according to claim 1, characterized in that the inertial separator is designed as a cyclone separator (6).

3. Steam turbine plant according to claim 2, characterized by at least one of the following features:

- The cyclone separator (6) is arranged vertically and has a vertical longitudinal central axis (9);

- A steam inlet (12) is tangentially connected to the cyclone separator (6);

- A steam outlet (13) is connected axially centrally or tangentially to the cyclone separator (6);

- The steam inlet (12) is connected in a lower end portion of a cylinder portion (10) of the cyclone separator (6) to the cyclone separator (6);

- The steam outlet (13) is connected in an upper end portion of a cylinder portion (10) of the cyclone separator (6) to the cyclone separator (6);

- The cyclone separator (6) has a cylinder portion (10) and a bottom of the cylinder portion (10) subsequent, downwardly tapering cone portion (11).

4. Steam turbine plant according to claim 2, characterized by at least one of the following features:

- The cyclone separator (6) has a spherical housing (15);

- A steam inlet (12) is tangentially connected to the housing (15);

- The steam inlet (12) is connected in an equatorial plane (16) to the housing (15); - A steam outlet (13) is connected coaxially to a longitudinal central axis (9) of the housing (15) to the housing (15);

- The steam outlet (13) associated longitudinal central axis (9) is perpendicular to the steam inlet (12) associated equatorial plane (16);

- An outlet opening (14) for removing in the housing (15) deposited impurities from the housing (15) is arranged coaxially to a longitudinal central axis (9 ') of the housing (15) on the housing (15);

- The outlet opening (14) associated longitudinal central axis (9 ') is arranged coaxially with the steam outlet (13) associated with the longitudinal central axis (9);

the longitudinal central axis (9 ') associated with the outlet opening (14) is perpendicular to the equatorial plane (16) associated with the steam inlet (12);

- The housing (15) is arranged vertically, such that the steam inlet (12) associated equatorial plane (16) extends substantially horizontally and / or that the steam outlet (13) associated longitudinal central axis (9) extends substantially vertically and or that the longitudinal central axis (9 ') associated with the outlet opening (14) extends substantially vertically.

5. Steam turbine plant according to one of claims 1 to 4, characterized by at least one of the following features:

- The inertial separator (6) is designed so that it can be operated at a vapor pressure of about 250 bar to about 350 bar and / or at a steam temperature of about 620 ⁰ C to about 720 ⁰ C;

- The inertial separator (6) is designed so that it precipitates particles having a particle size smaller than 0.5 mm or smaller than 0.1 mm from the steam;

- The inertial separator (6) is designed for the separation of oxide particles, in particular of magnetite or spinel.

6. A method for operating a steam turbine plant, in particular for power generation, in which steam from a steam generator (4) to a steam turbine (3) is guided, characterized in that the steam upstream of the steam turbine (3) entrained particles are removed.

7. The method according to claim 6, characterized in that the particles are eliminated by means of inertial forces from the steam.

8. Use of a Trägheitsabscheiders (6) for removing particles from a steam flow downstream of a steam generator (4) and upstream of a steam turbine (3) in a steam turbine plant (1), in particular for power generation.

9. Use according to claim 8, characterized by the characterizing features of at least one of claims 2 to 5.