Steam power installation comprising valve-stem leakage steam line

Abstract

A steam power installation has a steam turbine and a valve-stem leakage steam line. A fitting is arranged in the valve-stem leakage steam line, which fitting is used to conduct the valve-stem leakage steam into a suitable valve-stem leakage steam collector, such as into a condenser.

Claims

1. A steam power plant comprising a steam turbine, a steam line that is fluidically connected to the steam turbine and is designed to convey steam, a valve that is arranged in the steam line and is designed to change a quantity of steam flowing through the steam line, the valve comprising a first outlet to which the steam line connects, and a second outlet configured to convey valve-stem leakage steam that leaks past a valve stem of the valve, a valve-stem leakage steam line connected to the second outlet, and a valve-stem leakage steam collector that is fluidically connected to the valve-stem leakage steam line, and a fitting that is arranged in the valve-stem leakage steam line, wherein the valve-stem leakage steam collector is designed as a condenser, wherein the valve-stem leakage steam is conveyed via the valve-stem leakage steam line directly from the second outlet to the condenser, and wherein the fitting is configured to open whenever a pressure of valve-stem leakage steam in the valve-stem leakage steam line upstream of the fitting is above a pressure in the condenser, thereby passing all of the valve-stem leakage steam into the condenser.

2. The steam power plant as claimed in claim 1, wherein the fitting is designed as a flap.

3. The steam power plant as claimed in claim 2, wherein the flap is designed such that it is controlled.

4. The steam power plant as claimed in claim 2, wherein the flap is designed as a check flap.

5. The steam power plant as claimed in claim 1, wherein the fitting is designed as a valve.

6. The steam power plant as claimed in claim 1, further comprising: a safety valve arranged in the valve-stem leakage steam line.

7. A method for operating a steam power plant, wherein the steam power plant comprises: a steam turbine, a steam line that is fluidically connected to the steam turbine and is designed to convey steam, a valve that is arranged in the steam line and is designed to change a quantity of steam flowing through the steam line, the valve comprising a first outlet to which the steam line connects, and a second outlet configured to convey valve-stem leakage steam that leaks past a valve stem of the valve, a valve-stem leakage steam line connected to the second outlet, and a valve-stem leakage steam collector that is fluidically connected to the valve-stem leakage steam line, and a fitting that is arranged in the valve-stem leakage steam line, wherein the valve-stem leakage steam collector is designed as a condenser, wherein the valve-stem leakage steam is conveyed via the valve-stem leakage steam line directly from the second outlet to the condenser, the method comprising: opening the fitting whenever a pressure of valve-stem leakage steam in the valve-stem leakage steam line upstream of the fitting is above a pressure in the condenser to pass all of the valve-stem leakage steam to the condenser, and closing the fitting whenever the pressure of valve-stem leakage steam in the valve-stem leakage steam line upstream of the fitting is below the pressure in the condenser.

8. The method as claimed in claim 7, wherein a safety valve in the valve-stem leakage steam line opens to release more than a maximum pressure in the valve-stem leakage steam line.

9. A steam power plant, comprising: a first flow circuit in which steam flows into a steam valve, then out the steam valve via a first valve outlet, then through a steam line to a steam turbine; and a second flow circuit in which the steam flows into the steam valve, then leaks past a valve stem and a housing of the steam valve, then flows out the steam valve via a second outlet, then through a fitting configured to open whenever a pressure of the steam at the second outlet is above a pressure in a condenser, and then directly to the condenser.

10. The steam power plant of claim 9, wherein the fitting comprises a check flap.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The single FIGURE shows a steam power plant according to the invention.

DETAILED DESCRIPTION OF INVENTION

(2) With regard to additions to the teaching which is directly apparent in the drawing, reference is made to the relevant prior art.

(3) The FIGURE shows a steam power plant 1 comprising a steam turbine 2 that comprises a first turbine section 2a and a second turbine section 2b. For the sake of clarity, a boiler and a generator are not shown in greater detail. Furthermore, the first turbine section 2a is in the form of a combined high- and intermediate-pressure steam turbine.

(4) Live steam flows from a boiler (not shown in greater detail) via a quick-closing valve 3 and a control valve 4, fluidically connected to the quick-closing valve 3, into a steam line 5. Thus, the live steam flows first through the quick-closing valve 3, then through the control valve 4 and thence via the steam line 5 into the high-pressure section 2c of the first turbine section 2a. After flowing through the high-pressure section 2c of the first turbine section 2a, the steam flows out of the high-pressure section 2c (not shown), is reheated in an intermediate superheater and then flows, via an intermediate-pressure quick-closing valve 6 and intermediate-pressure control valve 7, into the intermediate-pressure section 2d of the first turbine section 2a.

(5) After flowing through the intermediate-pressure section 2d of the first turbine section 2a, the steam finally reaches the second turbine section 2b, which is designed as a low-pressure turbine. The steam line that fluidically connects the first turbine section 2a to the second turbine section 2b is not shown and is termed an overflow line.

(6) After flowing through the second turbine section 2b, the steam then flows into a condenser 8, where it condenses to water.

(7) For the sake of clarity, part of a seal steam system 9 is shown with the steam turbine 2. The steam flowing into the quick-closing valve 3 and the control valve 4 is characterized by a relatively high temperature and a high pressure. The steam flowing into the intermediate-pressure quick-closing valve 6 and the intermediate-pressure control valve 7 is characterized by a high temperature with a pressure that is lower than in the previous case.

(8) The valves 3, 4, 6 and 7 comprise a valve housing and a valve stem that moves a valve cone. A movement of the valve stem with the valve cone regulates the flow of steam through the valve and thus the quantity of steam flowing through the steam line 5. Each of the valves 3, 4, 6, 7 comprises a control unit 10 that is designed to control the valve stem.

(9) The valve-stem leakage steam flows out of the quick-closing valve 3 via a first valve-stem leakage steam line 11. Equally, valve-stem leakage steam flows out of the intermediate-pressure quick-closing valve 6, via a second valve-stem leakage steam line 12, into a common, third valve-stem leakage steam line 13. A fitting 14a is arranged in the third valve-stem leakage steam line 13. After the steam has flowed through the fitting 14a, the valve-stem leakage steam passes, via a fourth valve-stem leakage steam line 15, into a valve-stem leakage steam collector 16.

(10) The valve-stem leakage steam from the control valve 4 and the intermediate-pressure control valve 7 is formed in a similar manner to this. The valve-stem leakage steam from the control valve 4 is guided via a fifth valve-stem leakage steam line 17. The valve-stem leakage steam issuing from the intermediate-pressure control valve 7 enters a sixth valve-stem leakage steam line 18. The fifth valve-stem leakage steam line 17 and the sixth valve-stem leakage steam line 18 discharge into a common, seventh valve-stem leakage steam line 19 in which there is arranged a fitting 14b. After flowing through the fitting 14b, the leakage steam enters an eighth valve-stem leakage steam line 20 and thence, finally, the valve-stem leakage steam collector 16.

(11) In the third valve-stem leakage steam line 13, there is arranged, in addition to the fitting 14a, a first safety valve 21, and in the seventh valve-stem leakage steam line 19, there is arranged, in addition to the fitting 14b, a second safety valve 22.

(12) The fittings 14a and 14b are opened as soon as there is a flow of valve-stem leakage steam. The fittings 14a and 14b close again when there is no flow of valve-stem leakage steam.

(13) The fittings 14a and 14b can be designed as flaps. These flaps can be controlled, respectively, by a first control unit 23a and a second control unit 23b. In that context, the first control unit 23a actuates the first fitting 14a and the second control unit 23b actuates the second fitting 14b.

(14) In an alternative embodiment, the flap 14a, 14b can be designed as a check flap.

(15) Furthermore, the fittings 14a and 14b can be designed as a valve.

(16) The steam power plant 1 illustrated in the FIGURE is characterized in that the valve-stem leakage steam collector 16 is designed as a condenser 8. This may be a separator-condenser or the condenser that is fluidically connected downstream of the second turbine section 2b.

(17) Although the invention has been described and illustrated in more detail by way of the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variations can be derived herefrom by a person skilled in the art without departing from the scope of protection of the invention.