Steam turbine and method for operating same

Abstract

A steam turbine, having a steam turbine outer housing; a high-pressure inner housing having first process steam inlet and outlet sections for conducting process steam therethrough from the inlet to the outlet section in a first process steam expansion direction; a low-pressure inner housing having second process steam inlet and outlet sections for conducting process steam therethrough from the second process steam inlet section to the second process steam outlet section in a second process steam expansion direction; and an intermediate superheater, which is arranged downstream of the high-pressure inner housing and upstream of the low-pressure inner housing, wherein the high-pressure and low-pressure inner housings are arranged within the steam turbine outer housing and the high-pressure and the low-pressure inner housings are arranged in such a way that the first steam inlet section of the high-pressure inner housing faces the second steam inlet section of the low-pressure inner housing.

Claims

1. A steam turbine, comprising: a steam turbine outer housing, a high-pressure inner housing with a first process steam inlet portion and a first process steam outlet portion for conducting process steam through the high-pressure inner housing from the first process steam inlet portion to the first process steam outlet portion in a first process steam expansion direction, a low-pressure inner housing with a second process steam inlet portion and a second process steam outlet portion for conducting process steam through the low-pressure inner housing from the second process steam inlet portion to the second process steam outlet portion in a second process steam expansion direction, and an intermediate superheater which is arranged downstream of the high-pressure inner housing and upstream of the low-pressure inner housing, wherein the high-pressure inner housing and the low-pressure inner housing are arranged within the steam turbine outer housing, wherein the high-pressure inner housing and the low-pressure inner housing are arranged such that the first process steam inlet portion of the high-pressure inner housing faces toward the second process steam inlet portion of the low-pressure inner housing wherein, downstream of the high-pressure inner housing, there is formed a process steam diverting portion for diverting process steam from the first process steam outlet portion in a direction counter to the first process steam expansion direction into a cooling line of the steam turbine, wherein the cooling line is formed in a region adjacent to the high-pressure inner housing.

2. The steam turbine as claimed in claim 1, wherein the cooling line is arranged at least in certain portions between, or directly between, an inner wall of the steam turbine outer housing and an outer wall of the high-pressure inner housing.

3. The steam turbine as claimed in claim 1, wherein the cooling line is arranged at least in certain portions between, or directly between, an inner wall of the steam turbine outer housing and an outer wall of the low-pressure inner housing.

4. The steam turbine as claimed in claim 1, wherein, at an upstream end portion of the high-pressure inner housing, at which the first process steam inlet portion is formed, there is arranged a high-pressure sealing shell for at least partially sealing the upstream end portion of the high-pressure inner housing and, wherein at an upstream end portion of the low-pressure inner housing, at which the second process steam inlet portion is formed, there is arranged a low-pressure sealing shell for at least partially sealing the upstream end portion of the low-pressure inner housing, wherein the high-pressure sealing shell and the low-pressure sealing shell are arranged adjacent to one another.

5. The steam turbine as claimed in claim 1, wherein, at an upstream end portion of the high-pressure inner housing, at which the first process steam inlet portion is formed, and at an upstream end portion of the low-pressure inner housing, at which the second process steam inlet portion is formed, there is arranged a common sealing shell for at least partially sealing the two end portions.

6. The steam turbine as claimed in claim 1, wherein, at a downstream end portion of the low-pressure inner housing, there is formed a sealing web for sealing a steam turbine region between the downstream end portion of the low-pressure inner housing and the steam turbine outer housing.

7. The steam turbine as claimed in claim 1, wherein the intermediate superheater is arranged outside the steam turbine outer housing.

8. The steam turbine as claimed in claim 1, wherein the high-pressure inner housing and the low-pressure inner housing are provided as separate components in a single steam turbine outer housing.

9. A method for operating a steam turbine as claimed in claim 1, the method comprising: conducting process steam from a process steam source through the first process steam inlet portion into the high-pressure inner housing, conducting the process steam from the first process steam inlet portion to the first process steam outlet portion, and conducting the process steam through the first process steam outlet portion from the high-pressure inner housing via the process steam diverting portion and a cooling line to the intermediate superheater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures, in each case schematically:

(2) FIG. 1 shows a block diagram for illustrating a steam turbine according to a first embodiment of the present invention, and

(3) FIG. 2 shows a block diagram for illustrating a steam turbine according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF INVENTION

(4) Elements of identical function and mode of action are denoted in each case by the same reference designations in FIGS. 1 and 2.

(5) FIG. 1 illustrates a steam turbine 1a according to a first embodiment. The steam turbine 1a has a steam turbine outer housing 20, in which there are situated a high-pressure inner housing 30, a low-pressure inner housing 40 in the form of a medium-pressure inner housing, and a further low-pressure inner housing 90. Arranged upstream of the high-pressure inner housing 30 is a fresh steam or process steam source 10 for the supply of process steam to the high-pressure inner housing 30. The high-pressure inner housing 30 has a first process steam inlet portion 31 and a first process steam outlet portion 32 for conducting process steam through the high-pressure inner housing 30 from the first process steam inlet portion 31 to the first process steam outlet portion 32 in a first process steam expansion direction 33. The low-pressure inner housing 40 has a second process steam inlet portion 41 and a second process steam outlet portion 42 for conducting process steam through the low-pressure inner housing 40 from the second process steam inlet portion 41 to the second process steam outlet portion 42 in a second process steam expansion direction 43. The steam turbine 1a furthermore has an intermediate superheater 50, which is arranged downstream of the high-pressure inner housing 30 and upstream of the low-pressure inner housing 40.

(6) As illustrated in FIG. 1, the high-pressure inner housing 30 and the low-pressure inner housing 40 are arranged such that the first process steam inlet portion 31 of the high-pressure inner housing 30 faces toward the second process steam inlet portion 41 of the low-pressure inner housing 40.

(7) Downstream of the high-pressure inner housing 30, the steam turbine 1a has a process steam diverting portion 60 for diverting process steam from the first process steam outlet portion 32 in a direction counter to the first process steam expansion direction 33 into a cooling line 70 of the steam turbine 1a. The cooling line 70 is formed within the steam turbine outer housing 20 in a region adjacent to the high-pressure inner housing 30. The cooling line 70 is furthermore arranged in certain portions between an inner wall of the steam turbine outer housing 20 and an outer wall of the high-pressure inner housing 30. Furthermore, the cooling line 70 is arranged in certain portions between an inner wall of the steam turbine outer housing 20 and an outer wall of the low-pressure inner housing 40.

(8) In the first embodiment, at an upstream end portion of the high-pressure inner housing 30, at which the first process steam inlet portion 31 is formed, there is arranged a high-pressure sealing shell 34 for at least partially sealing the upstream end portion of the high-pressure inner housing 30. Furthermore, at an upstream end portion of the low-pressure inner housing 40, at which the second process steam inlet portion 41 is formed, there is arranged a low-pressure sealing shell 44 for at least partially sealing the upstream end portion of the low-pressure inner housing 40. The high-pressure sealing shell 34 and the low-pressure sealing shell 44 are arranged adjacent to one another. At a downstream end portion of the high-pressure inner housing 30, at which the first process steam outlet portion 32 is formed, there is arranged a further high-pressure sealing shell 35 for at least partially sealing the downstream end portion of the high-pressure inner housing 30.

(9) At a downstream end portion of the low-pressure inner housing 40, there is formed a sealing web 80 for sealing a steam turbine region between the downstream end portion of the low-pressure inner housing 40 and the steam turbine outer housing 20. The intermediate superheater is arranged outside the steam turbine outer housing 20. The high-pressure inner housing 30 and the low-pressure inner housing 40 are provided as separate components in a common steam turbine outer housing 20.

(10) A steam turbine 1b according to a second embodiment will be described with reference to FIG. 2. The steam turbine 1b according to the second embodiment corresponds substantially to the steam turbine 1a according to the first embodiment. Instead of the two separate sealing shells or the high-pressure sealing shell 34 and the low-pressure sealing shell 44, only a single sealing shell 100 is arranged between the high-pressure inner housing 30 and the low-pressure inner housing 40.

(11) A method according to an embodiment will be described below with reference to FIG. 1. In the context of the method, it is firstly the case that process steam from the process steam source 10 is conducted through the first process steam inlet portion 31 into the high-pressure inner housing 30. Subsequently, the process steam is conducted from the first process steam inlet portion 31 to the first process steam outlet portion 32 and subsequently through the first process steam outlet portion 32 from the high-pressure inner housing 30 via the process steam diverting portion 60 and the cooling line 70 to the intermediate superheater 50. Here, the process steam is conducted through the cooling line 70, for the purposes of cooling the steam turbine outer housing 20 or the steam turbine 1a, along the high-pressure inner housing 30 and along the low-pressure inner housing 40. After the process steam has been heated to a predefined temperature at constant pressure in the intermediate superheater 50, the heated or superheated process steam is conducted from the intermediate superheater 50 through the second process steam inlet portion 41 into the low-pressure or medium-pressure inner housing. From there, the process steam is conducted, maintaining the same expansion direction, into the further low-pressure inner housing. There, the process steam can expand further and condense.

LIST OF REFERENCE DESIGNATIONS

(12) 1 Steam turbine 10 Process steam source 20 Turbine outer housing 30 High-pressure inner housing 31 First process steam inlet portion 32 First process steam outlet portion 33 First process steam expansion direction 34 High-pressure sealing shell 35 High-pressure sealing shell 40 Low-pressure inner housing 41 Second process steam inlet portion 42 Second process steam outlet portion 43 Second process steam expansion direction 44 Low-pressure sealing shell 50 Intermediate superheater 60 Process steam diverting portion 70 Cooling line 80 Sealing web 90 Low-pressure inner housing 100 Sealing shell