DE102006004836A1 - Organic rankine cycle-turbo-generator, has generator section with stator housing that includes rotor chamber, which opens in direction of exhaust chamber of turbine section, where generator is provided between generator and turbine sections - Google Patents

Abstract

The turbo-generator has a generator section (A) that exhibits a stator housing (21) with a rotor chamber (22), which opens in a direction of an exhaust chamber (11) of a turbine section. The turbo-generator is provided in an axial arrangement between the generator and turbine sections. A friction bearing (14) is provided for mounting a generator shaft (17), where the friction bearing is lubricated by a precipitate of an organic rankine cycle (ORC)-working fluid. A cooling system of the generator section is designed in a form of a channel arrangement within a rotor and a stator.

Description

The This invention relates to an Organic Rankine Cycle (ORC) Turbogenerator in an axial arrangement between a turbine-steam housing and a Generator section according to the preamble of claim 1.

Of the Organic Rankine cycle (ORC for Engl. organic rankine cycle) is a thermodynamic process to operate steam turbines with a working fluid other than Water or water vapor. As a working medium in this cycle usually organic liquids used with a low evaporation temperature. Such a procedure is used especially when the available temperature gradient between heat source and heat sink too low for is a steam driven turbine. Such a cycle is therefore mainly used to generate electricity using geothermal energy, a cogeneration, used in solar power plants or marine thermal power plants.

at small plants with a capacity of less than 500 kW are the specific cost of a turbine generator unit in a conventional Design too big. In contrast to steam turbines, the corresponding thermodynamic cycles take place at a much lower temperature. This exists the possibility, to combine the turbine and the generator into one unit. This is in a known embodiment to an axial Arrangement of turbine and generator used. That's it Paddle wheel of the turbine mounted directly on the generator shaft. The attachment is preferred as a self-centering Attachment, e.g. executed a shepherd toothing. The turbine shaft will sealed by means of a mechanical seal to the outside and leads directly in the generator connected behind it.

such embodiments However, have the problem that the working medium especially in high speeds of the turbine through the mechanical seal at the Junction between turbine and generator due to material fatigue and resulting leaks of the mechanical seal penetrate to the outside can. Such turbogenerators thus require increased maintenance and associated greater maintenance costs.

It Thus, the task is a turbogenerator for use in a ORC circular process specify a robust, low maintenance and also has leak-proof construction at very high speeds. The required Turbogenerator should also an optimal internal cooling at one possible have compact and space-saving design.

The Task is with an ORC turbo generator with the characteristics of the Claim 1 solved, wherein the dependent claims appropriate or advantageous embodiments contain.

According to the invention ORC turbogenerator characterized in that the generator section a close to the environment dense and pressure-resistant trained stator housing in conjunction with a in the direction of Abdampfraumes the turbine section open runner room having.

in the In contrast to the embodiments known from the prior art, in which the turbine section and the generator section strictly are separated from each other forms in the ORC turbogenerator according to the invention the stator of the generator section together with the outer shell of the generator section Turbine section a continuous and the environment pressure-resistant and absolutely tight shell, while the runners room inside the stator is in communication with the Abdampfraum.

In order to deleted on the one hand, the plain bearing seal completely, with the sealing effort the turbine shaft considerably decreased and higher Speeds of the turbo generator can be achieved. The air friction in the runner interior between runner and stator is through the in the Abdampfraum the turbine section minimized prevailing negative pressure, which increases the mileage of the Turbogenerators in addition elevated.

The Storage of a generator shaft is expediently in the form of at least a lubricated by the condensate of the ORC working fluid plain bearing educated. The plain bearing serves for the storage of both the runner in Generator section, as well as arranged in the turbine section Turbine rotor. Through the use of the condensed and in the vapor phase again even impurity-separating ORC working fluid as a lubricant even after longer Useful periods of highly clean and self-sufficient lubricant circulation created.

The cooling the generator section is in the form of a condensate of the ORC working medium flowed through Channel arrangement within the rotor and / or stator formed. As a result, in addition a highly pure coolant circuit educated.

In an advantageous embodiment, the rotor has a central bore introduced within the generator shaft with a condensate inside the bore Cooling tube on. This advantageous embodiment prevents overheating of the rotor due to heat dissipation by the ORC condensate flowing inside the rotor.

Additionally is in an advantageous embodiment, at least one, the centric Bore in the runner with the sliding surface connecting the plain bearing and the condensate from the central bore in the plain bearing feeding Sliding bearing hole provided. The lubrication of the plain bearing is through this training with the coolant circuit within the runner coupled, the runner chilled and the plain bearing is lubricated targeted.

Additionally is a thermal decoupling at least between the stator and the steam housing the turbine section in the form of at least one radially of a coolant perfused, in the stator housing provided cavity expedient. These Design serves for cooling the stator, in particular the near the steam space of the turbine section located stator sections and prevention of thermal overload of the stator and thus of the generator section.

The flowing through the cavity coolant may also be the condensate of the ORC working fluid. In this Case becomes the working fluid in the working fluid circuit for driving the turbine and in the cooling and lubricating circuit are driven.

Of the ORC turbo-generator according to the invention will be described below using an embodiment in conjunction closer with a figure be explained. It will be for the same or equivalent parts use the same reference numerals.

For a more understandable Representation will be the turbo-generator in the following explanation divided into a generator section A and a turbine section B. However, the entire turbogenerator has a compact and integrated Structure on, wherein the sections A and B together a self-contained Form device.

The turbine section consists of a turbine housing 1 with a rotatably mounted within the housing impeller. The impeller has an impeller base 2 , a series of impeller blades 3 and an impeller cover 4 on. The impeller is exposed to the vaporous working medium via a nozzle. The nozzle consists of a nozzle body 5 , an optimally conductive the flow of the working medium nozzle opening 6 and a nozzle spacer 7 for locking the nozzle in an appropriate aerodynamic position to the impeller in the turbine section. A fastening bolt 8th ensures a secure fit of the impeller on a shaft 17 , whose structure is shown in detail below.

In the example shown here, the turbine impeller is driven tangentially, while the working fluid leaves the turbine section in the axial direction. The supply of the working medium via a Zudampföffnung 9 which are in a Zudampfkanal 10 empties. The Zudampfkanal 10 directs the hot, vaporous working medium in the mentioned nozzle opening 6 further. After leaving the turbine wheel, the working fluid enters an exhaust steam diffuser 11 that has an exhaust opening 30 derives the working medium to the outside.

The generator section A closes over a bearing plate 12 to the turbine section B on. Via a pressure equalization hole 13 is the interior of the generator section A, in particular its runner space 22 , with the interior of the turbine section B, in particular the space of the impeller connected. Both the impeller in the turbine section, as well as the rotor of the generator section are in a common sliding bearing 14 stored and sitting on the generator shaft 17 on. The generator shaft 17 is guided into the turbine section B. The impeller of the turbine section is there over the already mentioned fastening bolts 8th with the wave 17 connected.

The generator shaft 17 has one or more slide bearing bores 15 on top, with a centric bore 16 inside the generator shaft. About the centric bore 16 the condensate of ORC working medium is guided, the generator shaft 17 cooled and at the same time the running surface of the plain bearing 14 through that via the sliding bearing bore 15 out pressed condensate is lubricated. The centric bore 16 is via a standing inside the bore cooling tube 27 fed. The condensate contained therein passes under pressure both on the plain bearing 14 on the drive side of the generator section, as well as on a comparable second bearing 14b on the generator side.

The condensate is after passing through the plain bearing 14 over the exhaust steam diffuser 11 derived to the outside with the flow of the working medium.

In the embodiment shown here, the generator section is designed as a permanently excited synchronous generator. The rotor of the generator consists of a series of on the shaft 17 attached permanent magnet 18 , The permanent magnets can, for example, glued or secured with carbon fiber bands be. The stator winding consists in the illustrated embodiment of a stator winding 19 that with a casting 20 is provided. The stator and thus the entire generator section is in a stator housing 21 accommodated, directly to the turbine section B and its housing 1 connects and is tightly connected to this. As mentioned, the runner room 22 through the pressure equalization hole 13 continuously vented in the direction of the turbine section, in particular of the turbine interior. As a result of the prevailing fluid mechanics there is formed a partial negative pressure, which leads to a reduction of air friction in the runner space.

The stator housing 21 is cooled for thermal decoupling of the generator section A from the turbine section B. As a result, the heads of the stator winding in the generator section are protected against overheating. For this purpose, the stator housing at least in the connection region to the turbine section, ie on the drive side of the generator, an annular, radially through-flow of a coolant cavity 23 on. The cavity 23 closes in this embodiment, the actual stator cooling 24 on, which extends at least in sections over the lateral surface of the stator housing and is flowed through by the coolant in the axial direction. The components 23 and 24 be from a coolant flow 25 and a coolant return 26 charged or emptied.

The centric bore 16 is as described by the cooling tube 27 fed. The coolant flowing therein is forced into the central bore and passes over the slide bearing bores 15 and 15b in the plain bearings 14 and 14b out. The coolant, for which the condensate of the working medium is used as described, emerges from the sliding bearing 14 in the runner room 22 and is partially sucked from there into the turbine section B or via a coolant outlet 29 removed from the runner room. The inside of the plain bearing 14b Existing condensate leaves the area of the generator shaft 17 over a return 28 , The connections 27 . 28 and 28 form sections of an external, the turbo-generator associated coolant circuit to which also the inlets and outlets 25 and 26 can be connected. When using the condensate of the working medium as a coolant and lubricant of the turbogenerator, it makes sense to connect the connections for the supply and return of the coolant to the reservoir of the condensed working fluid. The necessary for the thermodynamic cycle process feed pump generates in this case the pressure required for the coolant and lubricant circuit. The condensate itself is largely free of impurities, since it undergoes a vapor phase in the thermodynamic cycle, in which the working medium separates from the impurities introduced by distillation processes.

The generator also has the usual electrical cable connections. In the example shown, these are from the stator winding via a cable partition 31 in a terminal box 32 with a conventional electrical circuit mounted therein, such as a rectifier circuit or the like out.

It It is clear that in the context of expert action in the embodiment shown a Set of changes can be done without the inventive idea to leave. Further embodiments emerge from the dependent claims.

A

generator section

B

turbine section

1

turbine housing

2

Wheel base

3

impeller blades

4

Impeller shroud

5

Nozzle body

6

nozzle opening

7

Die spacer

8th

mounting bolts

9

Zudampföffnung

10

Zudampfkanal

11

Abdampfdiffusor

12

end shield

13

Pressure compensating bore

14

bearings

14b

second bearings

15

plain bearing bore

15b

second plain bearing bore

16

centric drilling

17

generator shaft

18

permanent magnet

19

stator winding

20

grouting

21

The stator frame

22

runners room

23

cavity

24

Stator

25

Coolant supply

26

Coolant return

27

cooling pipe

28

returns

29

Coolant flow

30

Turbineabdampföffnung

31

cable insulation

32

terminal box

Claims (7)

Organic Rankine cycle (ORC) turbogenerator in an axial arrangement between a generator section (A) and turbine section (B), characterized in that the generator section is a close to the environment dense and pressure-resistant formed stator housing ( 21 ) with a in the direction of Abdampfraumes ( 11 ) of the turbine section open runner space ( 22 ) having. Turbogenerator according to claim 1, characterized in that at least one lubricated by the condensate of the ORC working fluid bearing ( 14 ) for supporting a generator shaft ( 17 ) is provided. Turbogenerator according to claim 1 or 2, characterized that cooling the generator section in the form of a through the condensate of the ORC working medium perfused Channel arrangement within the rotor and / or stator is formed. Turbogenerator according to claim 3, characterized in that the rotor one within the generator shaft ( 17 ) introduced centric bore ( 16 ) with a standing within the bore, the condensate introductory cooling tube ( 27 ) having. Turbogenerator according to claim 3 and 4, characterized by at least one the central bore ( 16 ) with the sliding surface of the sliding bearing ( 14 ) connecting and the condensate from the central bore in the sliding bearing supplying plain bearing bore ( 15 ). Turbogenerator according to one of the preceding claims, characterized by a thermal decoupling at least between the stator and the steam housing of the turbine section in the form of at least one radially flowed through by a coolant, in the stator housing ( 21 ) provided cavity ( 23 ). Turbogenerator according to claim 6, characterized in that the cavity ( 23 ) flowing coolant is the condensate of the ORC working medium.