STEAM TURBINE SYSTEM WITH STEAM TURBINE CLUTCH

Abstract

A steam turbine system and method of operating a steam turbine system including a steam generator coupled to a high pressure section and a low pressure section. The steam turbine system may further include to a first portion of a drive shaft coupled to the high pressure section and a clutching device for releasably coupling to a power generator coupled to the first portion of the drive shaft. The steam turbine system may also include a second portion of the drive shaft for coupling to the power generator coupled to the low pressure section. The method may be implemented using a controller of the steam turbine system.

Description

FIELD OF THE INVENTION

The disclosure relates generally to a steam turbine including a clutch for engaging or disengaging one or more high pressure sections from a power generator of the steam turbine, depending on a mode of operation.

BACKGROUND OF THE INVENTION

Many of today's steam turbines can be run in multiple modes of operation. For example, many turbines will run on high pressure steam during peak hours of operation and may switch to a low pressure steam during low energy generation. Typical steam turbines have a high pressure section and a low pressure section. However, when the turbine is run at a low pressure, the high pressure section is still utilized. In many cases, this results in a high pressure section being engineered to also accommodate low pressure steam, and thus low temperature steam. These configurations can alter the performance of the high pressure section, requiring changes in performance features as well as requiring moisture removal provisions within the high pressure section.

Further, the temperature changes associated with switching back and forth between a high pressure and high temperature steam to a low pressure and low temperature steam may cause thermal stress and thermal growth to components of the steam turbine.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments of the invention disclosed herein may include a steam turbine system comprising: a steam generator coupled to a high pressure section and a low pressure section; a first portion of a drive shaft coupled to the high pressure section; a clutching device for releasably coupling to a power generator coupled to the first portion of the drive shaft; and a second portion of the drive shaft for coupling to the power generator coupled to the low pressure section.

Embodiments of the invention may also include a method of operating a steam turbine system, the method comprising: delivering steam from a steam generator to at least one of a high pressure section and a low pressure section; engaging or disengaging, by a controller, a clutching device which is releasably coupled to a power generator via a first portion of a drive shaft from the high pressure section; and supplying power to the power generator via a second portion of the drive shaft which is coupled to the power generator from the low pressure section

BRIEF DESCRIPTION OF THE DRAWING

These and other features of the disclosure will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various aspects of the invention.

FIG. 1 shows an illustrative steam turbine system in a conventional configuration according to the prior art.

FIG. 2 shows an illustrative steam turbine with a steam turbine clutch engaged according to some embodiments of the invention.

FIG. 3 shows an illustrative steam turbine with a steam turbine clutch disengaged according to some embodiments of the invention.

FIG. 4 shows an illustrative concentrated solar power system including the steam turbine system according to some embodiments of the invention.

It is noted that the drawings may not be to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings. The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein is a steam turbine system including a steam turbine clutching device for disengaging a high pressure section from a power generator during low energy supply operation. Turning to FIG. 1, in the prior art, a steam generator 110 would provide steam to a high pressure section 120 of steam turbine system 100. The steam would expand within high pressure section 120 and exhaust from high pressure section 120 and would then pass to low pressure section 130. In low pressure section 130, the steam would again expand, exhausting to the condenser 140. During this operation, a first portion of a drive shaft 150 from high pressure section 120 and a second portion of the drive shaft 155 from low pressure section 130 would always provide shaft power to a power generator 160.

Still referring to FIG. 1, with both the first and second portions of the drive shafts 150 and 155 constantly supplying shaft power to power generator 160, high pressure section 120 and low pressure section 130 are both engineered to work with both high energy steam and low energy steam. However, these sections cannot be optimized for both operating condition.

Turning to FIG. 2, according to one embodiment, disclosed is a steam turbine system 200 for power generation with a steam turbine clutching mechanism. In one embodiment, steam turbine system 200 includes, similar to the prior art, a steam generator 210. Steam generator 210 is still coupled to a high pressure section 220, however steam generator 210 is also coupled to a low pressure section 230 via a system of pipes which may include valves, which will be described with more detail below. While a steam turbine system 200 is demonstrated in FIG. 2 with only two sections, embodiments of the disclosure can be utilized with any multiple numbers of coupled sections. According to some embodiments, a condenser 240 is coupled to low pressure section 230. Any known condenser for a steam turbine may be utilized. Unlike the prior art, high pressure section 220 is coupled to a first portion of a drive shaft 250, which is also coupled to a steam turbine clutch, or a clutching device 270, which is releasably coupled to a power generator 260. Clutching device 270 may include any known clutch. However, by example, clutching device 270 may include a single or multiple plate dry clutch, a wet clutch, or any planetary clutch.

Further regarding FIG. 2, low pressure section 230 is coupled to a second portion of the drive shaft 255 which is coupled to power generator 260 also. Releasably coupled indicates that clutching device 270 may be engaged in one position, or disengaged in a second position, from power generator 260, both while still being coupled to power generator 260, the function of which is further described below. While embodiments of the invention are described including a single drive shaft with two portions 250 and 255, with clutching device 270 releasably coupled between first portion of the drive shaft 250 and power generator 260, thus second portion of drive shaft 255 between clutching device 270 and coupled to low pressure section 230 and power generator 260, this is only illustrative. It should be understood that instead of portions of the drive shaft 250 and 255, two separate drive shafts may be utilized, or more if more than high pressure section 220 and low pressure section 230 are utilized.

Still referring to FIG. 2, clutching device 270 allows for steam turbine system 200 to be efficiently utilized for different modes of operations. For instance, when clutching device 220 is engaged, first portion of the drive shaft 250 supplies shaft power from high pressure section 220 to power generator 260. However, when clutching device 270 is disengaged, first portion of the drive shaft 250 does not supply power from high pressure section 220 to power generator 260. However, in both instances, second portion of the drive shaft 255 can provide shaft power to power generator 260 from low pressure section 230.

Clutching device 270 can be useful in a number of embodiments. For instance, clutching device 270 may be engaged during a period of higher energy output from steam turbine system 200, referred to as a high energy operating condition. A high energy operating condition can consist of a period of high pressure steam, high temperature steam, or a combination thereof. High energy operating conditions may include temperature ranges of approximately 370° C. to approximately 600° C. and a pressure range of approximately 6,895 kPa (1000 PSI) to approximately 20,684 kPa (3000 PSI), or approximately 6,895 kPa (1000 PSI) to approximately 13,790 kPa (2000 PSI). Further, clutching device 270 may be disengaged during a period of lower energy output from steam turbine system 200, referred to as a low energy operating condition. It should be understood that a low energy operating condition may include a period of low pressure steam, low temperature steam, or some combination thereof. Low energy operating conditions may include temperature ranges of approximately 100° C. to approximately 300° C. and a pressure range of approximately 414 kPa (60 PSI) to approximately 5,516 kPa (800 PSI), or approximately 689 kPa (100 PSI) to approximately 2,413 kPa (350 PSI).

By integrating clutching device 270 into steam turbine system 200, both high pressure section 220 and low pressure section 230 can be optimized for the proper operating conditions of each instance. For instance, since high pressure section 220, in some embodiments, may not be exposed to any low energy steam, advanced performance features may be integrated into this section and moisture removal systems may not need to be installed. This can provide a boost in the energy conversion efficiency of high pressure section 220. Further, low pressure section 230 can be further optimized for the handling of low energy steam. Another feature of the current disclosure is that rapid temperature changes that may occur during changes between high energy and low energy conditions can be obviated in high pressure section 220 by moving low energy steam directly to low pressure section 230, which will usually already exist at comparable temperatures to the low energy steam.

Still referring to FIG. 2, steam turbine system 200 may further include a system of valves to assist in the operation of clutching device 270. For instance, steam turbine system 200 may include a high pressure throttle valve 280 located between steam generator 210 and high pressure section 220, a high pressure bypass valve 285 located between steam generator 210 and low pressure section 230, and a low pressure throttle valve 290 between high pressure section 220 and low pressure section 230. When used in conjunction with clutching device 270, the system of valves can further aid in the redirection of steam during different operating conditions.

For instance, as illustrated in FIG. 2, high pressure throttle valve 280 and low pressure throttle valve 290 are both open, as indicated by the darkened valves, while clutching device 270 is engaged. High pressure bypass valve 285 is accordingly closed, as indicated by the white valve, so as not to bypass high pressure section 220. In this embodiment, steam will be allowed to flow from steam generator 210 to high pressure section 220 and then to low pressure section 230. This, as described above, can be useful during a high energy operating condition. Turning to FIG. 3, high pressure throttle valve 280 and low pressure throttle valve 290 are both closed while clutching device 270 is disengaged. High pressure bypass valve 285, on the other hand is open so as to bypass high pressure section 220. In this embodiment, steam can bypass high pressure section 230 from steam generator 210 and proceed directly to low pressure section 230. This, as described above, can be useful during a low energy operating condition to reduce strain on or damage to high pressure section 220.

As described above, in embodiments utilizing a system of valves, when clutching device 270 is engaged, first portion of the drive shaft 250 supplies power from high pressure section 220 to power generator 260. When clutching device 270 is disengaged, instead first portion of the drive shaft 250 does not supply power from high pressure section 220 to power generator 260. However, in both instances, second portion of the drive shaft 255 can provide shaft power to power generator 260 from low pressure section 230. Although described as a system of three valves, it should be understood that there may be more valves, especially in embodiments including more than the two disclosed sections, high pressure section 220 and low pressure section 230.

In a further embodiment, a method of operating steam turbine system 200 is disclosed. For instance, as shown in FIGS. 2 and 3, steam turbine system 200 may include a controller 295 coupled to steam turbine system 200. Controller 295 may be connected directly to steam generator 210, as illustrated. However, it should also be understood that controller 295 may be connected to any portion of steam turbine system 200, including being hardwired directly into the system logic, which is not illustrated. In any case, the method can be implemented using controller 295. Controller 295 may be automated, wherein it is capable of detecting an operating condition of steam turbine system 200 and adjusting accordingly. Controller 295 may also be programmable, such that it is programmed to run steam turbine system 200 at certain conditions based on many factors, such as time of day, current season, month, or year, average temperatures, or any other variables that may affect operating conditions of steam turbine system 200.

In any case, the method may include delivering steam from steam generator 210. Any known type of steam turbine system 200 with a steam generator 210 may be used. The steam is then sent to at least one of high pressure section 220 and low pressure section 230. The steam can be sent to sections 220 and 230 via any known mechanism, including but not limited to pipes typically fitted within steam turbine system 200. The steam expands through low pressure section 230 alone, or also through high pressure section 220. The method may also include engaging or disengaging, by controller 295, clutching device 270, which is releasably coupled to power generator 260 via first portion of the drive shaft 250 from high pressure section 220, as described above. Power is supplied to power generator 260 via second portion of the drive shaft 255, which is coupled to power generator 260 from low pressure section 230. The method may also include exhausting the steam to condenser 240, which may be coupled to low pressure section 230.

In the disclosed method, when clutching device 270 is engaged, as illustrated in FIG. 2, the method can include supplying shaft power from high pressure section 220 to power generator 260 via first portion of the drive shaft 250, as the steam can pass through both high pressure section 220 and low pressure section 230. Further, when clutching device 270 is disengaged, as illustrated in FIG. 3, first portion of the drive shaft 250 does not supply power from high pressure section 220 to power generator 260.

The method may further include utilizing high pressure throttle valve 280 between steam generator 210 and high pressure section 220, utilizing high pressure bypass valve 285 between steam generator 210 and low pressure section 230, and utilizing low pressure throttle valve 290 between high pressure section 220 and low pressure section 230. In such an embodiment, when clutching device 270 is engaged by controller 295, first portion of the drive shaft 250 supplies power from high pressure section 220 to power generator 260, and when clutching device 270 is disengaged by controller 295, first portion of the drive shaft 250 does not supply power from high pressure section 220 to power generator 260. However, whether clutching device 270 is engaged or disengaged, second portion of the drive shaft 255 supplies power from low pressure section 230 to power generator 260.

With further reference to these embodiments of the disclosed method, when clutching device 270 is engaged by controller 295, as shown in FIG. 2, high pressure throttle valve 280 and low pressure throttle valve 290 are opened by controller 295 to allow steam to pass through, and high pressure bypass valve 285 is closed by controller 295. However, when clutching device 270 is disengaged by controller 295, as shown in FIG. 3, high pressure throttle valve 280 and low pressure throttle valve 290 are closed by controller 295 so as to block steam from passing through high pressure section 220, and high pressure bypass valve 285 is opened by controller 295 to allow steam to pass through only low pressure section 230.

As further detailed above, in embodiments of the method, clutching device 270 may be engaged during a high energy operating condition, while clutching device 270 may be disengaged during a low energy operating condition.

Embodiments of this method may be beneficial to many steam turbine systems. As one example, this method may be beneficial in a concentrated solar power system, where clutching device 270 may be engaged during a daytime operating condition or clutching device 270 may be disengaged during a nighttime operating condition.

For example, in one embodiment, steam turbine system 200 is used in a concentrated solar power (CSP) system 300, as illustrated in FIG. 4. The CSP system 300 may include any type of concentrated solar power system (CSPS), such as a CSP steam turbine (CSPST) or CSP evaporator (CSPE) 300 which can include a plurality of solar receptors 310 of any known configuration. The solar receptors 310 can include, for example, reflecting and or absorbing solar surfaces such as mirrors, prisms, photovoltaic panels, or semi-transparent surfaces for either absorbing or redirecting solar energy from a solar energy source, such as the sun, in order to generate steam for powering steam turbine system 200, shown included in CSP system 300. In the case that the CSP system 300 includes a CSPST, it is understood that the CSPST can take the form of any conventional concentrated solar power steam turbine, in that it may include one or more parabolic troughs, focused boilers, or other components found in such CSPST systems. The depiction of the CSP system 300 herein is merely illustrative of one form of concentrated solar power steam turbine capable of interacting with the control systems and/or computer systems described according to the various embodiments of the invention.

Still referring to FIG. 4, CSP system 300, which is illustrative of a typical CSP system but may include any other CSP systems now known or later developed, can experience high energy operating conditions and low energy operating conditions. For instance, typically a daytime operating condition will consist of a higher energy operating condition due to the prevalence of sunlight. Such high energy operating conditions may include, for example, approximately 900° C. and approximately 6,205 kPa (1500 PSI). During this time, clutching device 270 will be engaged (FIG. 2) to allow for processing of a higher energy steam through both high pressure section 220 and low pressure section 230. However, a nighttime operating condition can often result in a lower energy operating condition due to the lack of sunlight, at which point clutching device 270 may be disengaged (FIG. 3) to more efficiently process the lower energy steam directly through low pressure section 230, bypassing high pressure section 220. Nighttime operating conditions may include approximately 400° C. and approximately 1724 kPa (250 PSI). It should be understood that not all daytime operating conditions may be high energy operating conditions. For instance, on cloudy or overcast days, it may be optimal to run at low energy nighttime operating conditions.

It should be understood that while the invention has been described as utilizing only one high pressure section 220, one low pressure section 230, one condenser 240, one clutching device 270, and three valves, more of each of these elements may be utilized in steam turbine system 200. For instance, multiple low pressure sections 230 may be utilized, or a plurality of high pressure sections 220, each of which may be releasably coupled individually. Further, any steam turbine system 200 with multiple sections now known or later developed may benefit from features of the invention, especially in the case of multiple operating conditions, be they based on energy, pressure, temperature, or any combination thereof. Each section may be optimized to run at particular conditions based on the turbine configuration and steam output.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims

1. A steam turbine system comprising:

a steam generator coupled to a high pressure section and a low pressure section;

a first portion of a drive shaft coupled to the high pressure section;

a clutching device for releasably coupling to a power generator coupled to the first portion of the drive shaft; and

a second portion of the drive shaft for coupling to the power generator coupled to the low pressure section.

2. The steam turbine system of claim 1, wherein in response to the clutching device being engaged, the first portion of the drive shaft supplies power from the high pressure section to the power generator and in response to the clutching device being disengaged the first portion of the drive shaft does not supply power from the high pressure section to the power generator.

3. The steam turbine system of claim 1, further comprising:

a high pressure throttle valve between the steam generator and the high pressure section;

a high pressure bypass valve between the steam generator and the low pressure section; and

a low pressure throttle valve between the high pressure section and the low pressure section.

4. The steam turbine system of claim 3, wherein in response to the clutching device being engaged, the first portion of the drive shaft supplies power from the high pressure section to the power generator and in response to the clutching device being disengaged the first portion of the drive shaft does not supply power from the high pressure section to the power generator.

5. The steam turbine system of claim 4, wherein in response to the clutching device being engaged, the high pressure throttle valve and the low pressure throttle valve are opened and the high pressure bypass valve is closed.

6. The steam turbine system of claim 4, wherein in response to the clutching device being disengaged, the high pressure throttle valve and the low pressure throttle valve are closed and the high pressure bypass valve is opened.

7. The steam turbine system of claim 1, wherein the clutching device is engaged during a high energy supply operating condition and the clutching device is disengaged during a low energy supply operating condition.

8. The steam turbine system of claim 7, wherein the high energy supply operating condition consists of a period of time wherein steam comprises at least one of: a high pressure steam and a high temperature steam; and wherein the low energy supply operating condition consists a period of time wherein steam comprises of at least one of: a low pressure steam and a low temperature steam.

9. The steam turbine system of claim 1, further comprising a concentrated solar power system operably coupled to the steam turbine system.

10. The steam turbine of claim 9, wherein the clutching device is engaged during a daytime operating condition and the clutching device is disengaged during a nighttime operating condition.

11. A method of operating a steam turbine system, the method comprising:

delivering steam from a steam generator to at least one of a high pressure section and a low pressure section;

engaging or disengaging, by a controller, a clutching device which is releasably coupled to a power generator via a first portion of a drive shaft from the high pressure section; and

supplying power to the power generator via a second portion of the drive shaft which is coupled to the power generator from the low pressure section.

12. The method of claim 11, wherein in response to the clutching device being engaged by the controller, the first portion of the drive shaft supplies power from the high pressure section to the power generator and in response to the clutching device being disengaged by the controller, the first portion of the drive shaft does not supply power from the high pressure section to the power generator.

13. The method of claim 11, further comprising:

utilizing a high pressure throttle valve between the steam generator and the high pressure section;

utilizing a high pressure bypass valve between the steam generator and the low pressure section; and

utilizing a low pressure throttle valve between the high pressure section and the low pressure section.

14. The method of claim 13, wherein in response to the clutching device being engaged by the controller, the first portion of the drive shaft supplies power from the high pressure section to the power generator and in response to the clutching device being disengaged by the controller the first portion of the drive shaft does not supply power from the high pressure section to the power generator.

15. The method of claim 14, wherein in response to the clutching device being engaged, the high pressure throttle valve and the low pressure throttle valve are opened by the controller and the high pressure bypass valve is closed by the controller.

16. The method of claim 14, wherein in response to the clutching device being disengaged, the high pressure throttle valve and the low pressure throttle valve are closed by the controller and the high pressure bypass valve is opened by the controller.

17. The method of claim 11, wherein the clutching device is engaged by the controller during a high energy supply operating condition and the clutching device is disengaged by the controller during a low energy supply operating condition.

18. The method of claim 17, wherein the high energy supply operating condition includes at least one of: a high pressure steam and a high temperature steam; and wherein the low energy operating condition includes at least one of: a low pressure steam and a low temperature steam.

19. The method of claim 11, further comprising a concentrated solar power system operably connected to the steam turbine system.

20. The method of claim 19, wherein the clutching device is engaged during a daytime operating condition and the clutching device is disengaged during a nighttime operating condition.