Deflection housing arrangement for a steam turbine arrangement and steam turbine arrangement comprising such a deflection housing arrangement

Abstract

The invention relates to a deflection housing arrangement (1) for a steam turbine arrangement (2), wherein the steam turbine arrangement (2) comprises at least one condensing turbine (3), at least one water-cooled condenser (4), and at least one air-cooled condenser (5). The deflection housing arrangement (1) comprises a deflection housing (6), wherein the deflection housing (6) has at least one axial passage (8) relative to the turbine axis (7) through which steam can flow from the condensing turbine (3) to the air-cooled condenser (5), and at least one radial passage (9) relative to the turbine axis (7) through which steam can flow from the condensing turbine (3) to the water-cooled condenser (4). Furthermore, the deflection housing arrangement (1) comprises at least one shut-off device (10) which enables a vacuum-tight seal of the axial passage (8). The invention also relates to a steam turbine arrangement (2) with such a deflection housing arrangement (1).

Description

[0001] The invention relates to a deflection housing arrangement for a steam turbine arrangement according to the preamble of independent claim 1 and to a steam turbine arrangement with such a deflection housing arrangement according to the preamble of independent claim 7.

[0002] In particular, the invention relates to a solution for the efficient condensation of the exhaust steam of a condensing turbine, wherein the steam is condensed in a condenser downstream of the condensing turbine.

[0003] There are two basic types of condensers used in such steam turbine arrangements: air-cooled condensers and water-cooled condensers. Due to ongoing global climate change, water levels and flow in rivers and canals are rapidly decreasing during the summer months. At the same time, temperatures in these waters are reaching record highs, which, due to legal limits, prohibits both the extraction of cooling water and the discharge of heated cooling water. These circumstances are driving the increasing use of hybrid cooling systems that combine both air- and water-cooled condensers.

[0004] To offer and implement a cost-effective and operationally optimized solution for industrial steam turbines, the installation configuration described below was developed. This configuration combines a water-cooled condenser, which operates from late summer to early summer, with an air-cooled condenser, which operates during the height of summer. This combination presents particular challenges for the design of the steam turbine set and its subsequent installation. The decisive factor is the significant difference in the vacuum generated during operation with these hybrid units: approximately 15 to 80 mbar during exhaust steam condensation with cooling water, compared to approximately 150 to 300 mbar during exhaust steam condensation with air.

[0005] For air condensers, the use of axial exhaust housings has become the global standard. This takes into account the fact that air condensers require a certain installation height (air intake from below), and therefore the use of axial exhausts on a relatively low turbine table or block foundation enables optimal flow and transfer of the exhaust steam to the air condenser, resulting in low flow and pressure losses. When using water-cooled condensers, which are often located below the table, the use of radial exhaust housings is still frequently preferred.

[0006] To operate a hybrid system with a deep vacuum when coupled to the water-cooled condenser, isolating the air-cooled condenser is essential. Otherwise, leaks in the air-cooled condenser will repeatedly break the vacuum, significantly shortening the expansion phase. Operating with the air-cooled condenser is expected to result in power losses of up to 15% of the nominal power.

[0007] To enable the future implementation of hybrid condensate systems consisting of water- and air-cooled condensers with optimized design and installation, axial discharge is preferred. Previously, hybrid cooling systems were used in conjunction with steam extraction, requiring switching between a water-cooled condenser and an air-cooled condenser. Initially, ball valves were used to switch the exhaust steam lines, but these proved unreliable due to rust and dirt deposits. The subsequent conversion to large butterfly valves was very expensive and only partially solved the technical problem.

[0008] One possible solution would be to use a so-called hotbox for connecting the air condenser when water-cooled condensers are mounted side-by-side or horizontally. However, this solution leads to a significant increase in the volume of the nacelle or weatherproof enclosure and is therefore very expensive. Furthermore, the exhaust cross-section must be reinforced to prevent vacuum drafts and implosion, which results in increased losses and thus a considerable reduction in performance.

[0009] A shortage of cooling water leads to inefficient part-load operation or even the shutdown of steam power plants. A continuous supply of process steam is then only possible via highly inefficient bypass steam systems.

[0010] The object of the present invention is to provide an improved deflector housing arrangement for a steam turbine assembly, enabling an efficient and cost-effective solution for operation with hybrid cooling systems. Furthermore, it is an object of the present invention to provide a steam turbine assembly with such a deflector housing arrangement.

[0011] The problem is solved with regard to the deflection housing arrangement by the features of independent claim 1 and with regard to the steam turbine arrangement by the features of independent claim 7.

[0012] Further embodiments of the invention, which can be used individually or in combination with each other, are the subject of the dependent claims.

[0013] The deflection housing arrangement according to the invention for a steam turbine arrangement, wherein the steam turbine arrangement comprises at least one condensing turbine, at least one water-cooled condenser, and at least one air-cooled condenser, is characterized in that the deflection housing arrangement comprises a deflection housing, wherein the deflection housing has at least one passage axial to the turbine axis through which steam can flow from the condensing turbine to the air-cooled condenser, and has at least one passage radial to the turbine axis through which steam can flow from the condensing turbine to the water-cooled condenser, and wherein at least one shut-off device is provided which enables a vacuum-tight seal of the axial passage.

[0014] By using a vacuum-tight seal for the axial passage, coupling with the water-cooled condenser is possible without the vacuum being repeatedly broken by leaks in the air condenser.

[0015] One embodiment of the deflection housing arrangement according to the invention provides that the shut-off device comprises a plug disc and / or a vacuum-tight shut-off valve.

[0016] Unlike other shut-off devices, such as ball valves, which are prone to rust and dirt deposits that regularly lead to malfunctions, disc and / or vacuum-tight butterfly valves are robust due to their simple design and are also cost-effective. When using a vacuum-tight butterfly valve, the disc does not need to be removed and reinstalled, thus avoiding downtime and ensuring continuous plant operation.

[0017] A further embodiment of the invention provides that the plug-in disc includes a radial deflecting diffuser. The deflecting diffuser can be optimized in terms of flow characteristics to reduce / minimize flow losses caused by the deflection of the exhaust steam.

[0018] Further embodiments of the invention provide that the deflector housing has an additional opening for introducing bypass steam and that the shut-off device includes an automatic switching device that operates depending on predefined parameters. Predefined parameters could include, for example, the inlet temperature of the water-cooled condenser and / or the available quantity of cooling water.

[0019] The steam turbine arrangement according to the invention, comprising a deflection housing arrangement according to one of the preceding claims, is characterized in that the condensing turbine, the deflection housing and the shut-off device are arranged inside a machine house or under a weather protection hood on a table top / a foundation / a frame and the water-cooled condenser is arranged below or laterally next to the table top / the foundation / the frame inside the machine house or under a weather protection hood.

[0020] The described tandem installation arrangement enables optimized exhaust steam flow and time-saving assembly and disassembly of the plug-in disc. Furthermore, the use of a vacuum-tight shut-off valve allows for easy separation of the air condenser. The economical hybrid operation of the cold end inherent in the invention makes a significant contribution to decarbonization in times of increasing river water scarcity, as it enables performance-optimized and continuous operation, particularly for process steam or heating steam power plants, potentially in conjunction with waste incineration. Water-cooled operation considerably increases power output by achieving a significantly deeper vacuum.

[0021] Further advantages and embodiments of the invention are explained below using exemplary embodiments. These will show: Fig. 1 : The basic structure of a steam turbine arrangement according to the invention with a deflection housing arrangement according to the invention Fig. 2 : A deflection housing arrangement according to the invention with a plug-in disc with flow-optimized deflection geometry.

[0022] The illustrations are merely schematic and not necessarily to scale. Essentially, only the components necessary for understanding the invention are shown. Identical or functionally equivalent components are identified by the same reference numerals across all figures.

[0023] Fig. 1 Figure 1 shows the basic structure of a steam turbine arrangement 2 according to the invention, including a deflector housing arrangement 1 according to the invention. In addition to the deflector housing arrangement 1, the steam turbine arrangement 2 comprises a condensing turbine 3, a water-cooled condenser 4, and an air-cooled condenser 5. In the exemplary embodiment, the steam turbine arrangement 2 has a further (extraction) back-pressure turbine 14 with a rigidly coupled generator 16 (gearbox use possible). An SSS coupling is arranged between the back-pressure turbine 14 and the condensing turbine 3, enabling automatic decoupling and disconnection of the condensing section.

[0024] The condensing turbine 3, the deflector housing 6, and the shut-off device 10 are arranged inside a machine house or under a weather protection hood (not shown in the figure) on a tabletop 13 (foundation / frame). The water-cooled condenser 4 is arranged below or to the side of the tabletop 13 inside the machine house or under the weather protection hood, whereas the air-cooled condenser 5 is arranged outside the machine house or weather protection hood, and the steam is guided to the air-cooled condenser 5 via an axial outflow through the machine house wall or weather protection hood.

[0025] The deflection housing assembly 1 comprises a deflection housing 6 and a shut-off device 10. The shut-off device 10 can be integrated into the deflection housing 6 or be a separate component. The deflection housing 6 has an axial passage 8 relative to the turbine axis 7, through which steam can flow from the condensing turbine 3 to the air-cooled condenser 5. Furthermore, the deflection housing 6 has a radial passage 9 relative to the turbine axis 7, through which steam can flow from the condensing turbine 3 to the water-cooled condenser 4. A radial opening 12 is also provided for introducing bypass steam into the deflection housing 6.

[0026] The shut-off device 10 enables a vacuum-tight seal of the axial passage 8. The vacuum-tight seal is achieved via a baffle plate or a vacuum-tight butterfly valve. When using a vacuum-tight butterfly valve, the baffle plate does not need to be removed and reinstalled, thus avoiding downtime and ensuring continuous plant operation. The butterfly valve can be controlled automatically based on predefined parameters. These parameters can include, for example, the inlet temperature of the water-cooled condenser 4 and / or the available cooling water volume. Appropriate measuring and control technology must be provided for measuring the parameters and controlling the butterfly valve. When using a baffle plate for a vacuum-tight seal, its flow characteristics can be optimized to minimize flow losses due to steam deflection.To ensure a secure seal, several shut-off devices can also be arranged in series.

[0027] Fig. 2 shows a deflection housing arrangement 1 according to the invention with a deflection housing 6 and a plug-in disc 10 as a shut-off element.

[0028] The deflection housing 6 comprises four openings (9, 12, 14, 15), allowing for an axial or a radial passage. The steam can be directed to the air-cooled condenser via the axial passage and to the water-cooled condenser via the radial opening 9 (see also Fig. 1 ). Bypass steam can be introduced into the deflection housing 6 via the additional opening 12.

[0029] The axial passage can be closed by means of the plug-in disc 10. A slide-in housing can be provided for inserting the plug-in disc, which is designed separately or as an integral part of the deflection housing 6.

[0030] The plug-in disc 10 features a flow-optimized deflection geometry 11. The deflection geometry 11 is designed as an integrated deflection diffuser and is three-dimensional at its end. The deflection geometry 11 enables a flow-optimized redirection of the steam from a largely axial inflow into the deflection housing 6 to a largely radial outflow from the deflection housing 6 to the water-cooled condenser. The deflection diffuser may need to be stiffened to prevent vibrations.

Claims

1. Deflection housing arrangement (1) for a steam turbine arrangement (2), wherein the steam turbine arrangement (2) comprises at least one condensing turbine (3) as well as at least one water-cooled condenser (4) and at least one air-cooled condenser (5), characterized by the fact that the deflection housing arrangement (1) comprises a deflection housing (6), wherein the deflection housing (6) has at least one axial passage (8) to the turbine axis (7) through which steam can flow from the condensing turbine (3) to the air-cooled condenser (5) and has at least one radial passage (9) to the turbine axis (7) through which steam can flow from the condensing turbine (3) to the water-cooled condenser (4), and wherein at least one shut-off device (10) is provided which enables a vacuum-tight seal of the axial passage (8).

2. Deflection housing arrangement (1) according to claim 1, characterized by the fact thatthe shut-off device (10) comprises a plug disc and / or a vacuum-tight butterfly valve.

3. Deflection housing arrangement (1) according to claim 2, characterized by the fact that the plug-in disc includes a radial deflecting diffuser (11).

4. Deflection housing arrangement (1) according to one of the preceding claims, characterized by the fact that In the deflection housing (6) a further opening (12) is provided for introducing bypass steam.

5. Deflection housing arrangement (1) according to one of the preceding claims, characterized by the fact that the shut-off device (10) includes an automatic switching device depending on predefinable parameters.

6. Deflection housing arrangement (1) according to claim 5, characterized by the fact that A predefinable parameter is the flow temperature of the water-cooled condenser and / or the available amount of cooling water.

7. Steam turbine arrangement (2) comprising a deflection housing arrangement (1) according to any one of the preceding claims, characterized by the fact thatthe condensation turbine (3), the deflection housing (6) and the shut-off device (10) are arranged inside a machine house or under a weather protection hood on a table top / a foundation / a frame (13) and the water-cooled condenser (4) is arranged below or to the side of the table top / the foundation / the frame (13) inside the machine house or weather protection hood.

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