EP2414730B1 - Device for phase separating a multi-phase fluid flow, steam turbine plant having such a device, and associated operating method - Google Patents

Description

The invention relates to an apparatus for phase separation of a multiphase fluid flow with a substantially around a central axis rotationally symmetrical designed, enclosing a cavity housing, with at least one supply line for the fluid flow, which is designed for a substantially ta ngential to the housing interior inflow of the fluid stream, and at least one discharge line for the separated gaseous portion of the fluid stream. The invention further relates to a steam turbine plant with a high-pressure turbine and a low-pressure turbine and with such a device. It also relates to a method for operating such a steam turbine plant.

In power plants, in particular nuclear power plants, in which steam is used for power generation or energy conversion, usually different turbines are used, which operate with different vapor pressure. The live steam generated in a power plant is directed, for example, in a high-pressure turbine, doing work there and is thus relaxed. Now, before the steam is introduced into a low pressure turbine designed for lower vapor pressure, its water content is usually reduced. In addition, there is usually an overheating of the steam before it is introduced into the low-pressure turbine. By these measures, on the one hand, the efficiency of the low-pressure turbine is increased, on the other hand, the life of the turbine is increased because damage, which may arise, for example, by drop erosion or corrosion of the components can be reduced or avoided.

In order to treat the expanded steam emerging from the high-pressure turbine in such a manner, water separators connected in series and reheaters are usually used which can be structurally combined in the manner of a secondary or a series installation (combined water separator / Reheater, short WaZü). In this case, the water content of the steam is usually reduced in a first component of the water separator / reheater before the now substantially gaseous portion is passed into a second component in which it is superheated. The thus superheated steam is now introduced into the low-pressure turbine, where it is relaxed and thereby performs work.

US 426 26 302 discloses a device for phase separation according to the prior art.

Various devices can be used to separate the water content. These include, for example, sheets on which the steam flow is passed along. For separation of the water content, it is also possible to use a so-called cyclone separator or cyclone, in the essentially rotationally symmetrical housing of which the vapor stream is introduced tangentially to the inner side of the housing. As a result, the heavier water content is forced outward by the centrifugal force, and the lighter, substantially gaseous portion flows due to the forming in the cyclone flow conditions in the interior of the housing surrounded cavity and collects there. In both cases, the gaseous portion of the vapor is now passed into a downstream and structurally / spatially separated second component of the WaZü, in which it is superheated. This is usually achieved by the heating of the steam pipes, which heat the steam by heat transfer accordingly or overheat.

US6516617 discloses a method of the prior art.

Thus, the deposition of water or the reheating of the steam can be done satisfactorily, the respective components must be dimensioned correspondingly large volumes, resulting in a corresponding material cost and space required immediately. On the other hand, in the construction of power plants as low as possible material requirements and space requirements are desirable.

The invention is therefore based on the object to provide a device for phase separation of a multi-phase fluid flow, which is suitable for heating the gaseous portion of the fluid stream, eg steam, and low demands on material and space requirements. Furthermore, a steam turbine plant with a high-pressure turbine and a low-pressure turbine, in which such a device particularly can be used advantageously indicated. Furthermore, a method for operating such a steam turbine plant is to be specified.

With regard to the device for phase separation of a multiphase fluid flow, this object is achieved according to the invention in that heating elements designed in the cavity for heating the gaseous fraction are arranged in an annular space concentric with the central axis.

Advantageous embodiments of the invention are the subject of the dependent claims.

The invention is based on the consideration that the comparatively large space requirement of conventional water separators / reheaters is based inter alia on the fact that the separation of water from the steam originally leaving the high-pressure turbine and the subsequent overheating of the separated gaseous fraction occur chronologically successively in two spatially separate spaces Spaces or device components takes place, which are arranged one behind the other in the manner of a flow-side series connection. As a result, specific requirements are placed on the structural design of the water separator / reheater, the system requires a relatively large installation space.

However, as has now been recognized, these two space regions do not necessarily have to be arranged structurally in succession in separate housings. Assuming suitable flow conditions, these spatial regions can also be arranged nested in one single housing, wherein the liquid separation and the superheating of the gaseous fluid fraction for a given volume element of the fluid take place substantially simultaneously or shortly one after the other.

Such suitable flow conditions are provided by a cyclone-type water separator. Due to the tangential influx of the inside of the housing of the cyclone takes place by acting on the current centrifugal force, the deposition of the heavy component, such as water, in the outer region of the housing surrounded by the cavity on the inside of the housing. The lighter, gaseous Proportion of the original fluid stream, for example water vapor, flows into the interior of the cavity. If, in an inner or middle region of the cavity, in particular in an annular space, heating elements for heating or overheating the gaseous portion are arranged in such a way that the passage of the lighter phase into the inner area is still possible, the gaseous portions become directly during their passage heated or overheated in the interior. As a result, an inner space area, which essentially contains the superheated steam, arises in the interior of the outer space area designed for water separation. The superheated, gaseous portion can then be led out of the inner space area and used as needed. By this nesting of two functionally different space areas, a combined water separator / reheater can be realized in a very compact design. In addition, material costs can be saved since only one housing is required for the two processes.

Such a construction is not limited to the treatment of water vapor. It can always be used when one or more phases of heavy particles or constituents are to be separated off from a multicomponent fluid flow, and the light fraction or portions of the original fluid stream are to be heated.

In a preferred embodiment, the annular space is designed with the heating elements for a flow through the gaseous portion of the fluid stream. In doing so, it separates the cavity into an inlet space lying between the inside of the housing and the annular space and a discharge space located inside the annular space. A clear separation of the two spatial areas allows optimized separation of the two successive processes. It is particularly advantageous if the portion of the fluid flow flowing into the inflow space has the smallest possible proportion of the heavy component in order to save energy for its heating. When used in a steam turbine plant thereby efficiency and lifetime or maintenance intervals of the turbine can be increased.

Depending on the composition of the multicomponent fluid flow, different embodiments of the rotationally symmetrical housing are advantageous. For example, the housing can taper toward one direction, in particular in the direction of the discharge line (flow outlet), in its cross section. A separation of water from a steam / water stream is preferably carried out in a substantially hollow cylindrical housing.

To optimally utilize gravity to separate the heavy component of the multiphase fluid stream, the central axis of the housing preferably has a substantially vertical orientation. The heavy component of the fluid flow then moves (flows) down the inside of the housing and can be collected or removed there. In general, a vertical installation of the cyclone separator is advantageous since in this case the force of gravity does not cause any imbalance in the turbulent flow.

For use of the apparatus in a steam turbine plant having a high-pressure turbine and a low-pressure turbine, the steam taken from the high-pressure turbine should be supplied to the low-pressure turbine in the overheated state. For this purpose, the heating elements should be designed with regard to their heating power to overheat the gaseous portion of the fluid stream, in particular water vapor.

The most effective use of the device is achieved when the multiphase fluid flow is supplied through multiple supply lines. If the supply lines-at least in the region of their housing connection-lie in a plane substantially perpendicular to the central axis of the housing, they are advantageously designed such that the velocity vector of the fluid flow flowing into the cavity has a component facing out of this plane. Here, an averaged velocity vector is meant, which is averaged over the individual components of the fluid flow. Thereby, it can be prevented that the fluid streams flowing in through the various supply lines collide with each other, and the fluid flows receive a preferential direction in the direction of the central axis. Advantageously, the fluid flow flows at an angle between 10 ° and 30 °, in particular of about 15 °, to a plane perpendicular to the central axis. That is, the result of the Wandgeometrie adjusting vortex flow is preferably superimposed on a velocity component in the direction of the central axis, so that overall forms a helical flow. In a vertical installation of the separation device, the velocity component directed in the direction of the center axis advantageously points downwards.

Preferably, four supply lines are used for the inflow of the fluid flow, which are arranged distributed uniformly and symmetrically over the circumference of the housing. With suitable dimensioning of the housing, the inflowing fluid flow can advantageously be divided in this way into four equal areas of the inside of the housing, without the individual streams meeting and interfering with each other.

The flow conditions forming in the housing of the device ensure that the gaseous portion of the fluid flow flows into the interior of the cavity surrounded by the housing. There it flows to the heating elements and is heated or overheated. The direction in which the heating elements are flown can be optimized by guide vanes or guide vanes arranged in the inflow space. For example, can be achieved in this way that the heating pipes are flowed substantially frontal, or the tangential component can be reduced. On the other hand, as these vanes reduce the inflow space, it should be decided, depending on the application, whether and with what dimensions they are used.

If necessary, if the degree of separation achieved by the cyclone effect is too poor and the gaseous portion of the fluid stream which crosses into the interior carries with it a quantity of the heavier liquid component which is too large for the intended use or for further heating, then in the inflow space further separation fine separator can be arranged. The condensate forming in the fine separator can be removed from the cavity by condensate drainage.

The device is suitable for both single-stage and multi-stage (intermediate) overheating. For two- or multi-stage overheating, for example, two or more groups of heating elements can be arranged one behind the other in the annular space in the direction of the central axis. The heating elements belonging to the individual groups can be designed for different heating outputs or heating temperatures.

In a preferred embodiment of the device, the heating elements are designed tubular. For heating or overheating of the gaseous fraction, the heating elements can be flowed through by a fluid heating medium, in particular water vapor. For a multi-stage heating can be used, for example, in different groups of heating elements steam with different pressure and / or different temperature.

For most effective heating of the gaseous portion rectilinear pipes are used as heating elements, which are aligned parallel to the central axis of the building. For this purpose, a plurality of tubes can be arranged in the annular space, which can be designed differently depending on the application. For example, smooth tubes or finned tubes, or favorable combinations of these tube types can be used. Conveniently, the individual tubes are spaced apart from each other such that the unhindered passage of the gaseous phase separated from the fluid flow from the outer inflow space into the inner outflow space can take place through the remaining interspaces. On the other hand, of course, a certain "density" of pipes is required to achieve the desired heating effect.

The heating tubes are advantageously combined into tube bundles. In this case, so-called ring bundles can be used, in which the tubes are arranged more or less evenly distributed in the annular space. Alternatively or in combination, so-called single bundles can be used. In each case a plurality of mutually adjacent heating elements are combined to form a bundle. The individual bundles can be pre-assembled and can be handled as a whole. If necessary, they are easier to assemble, dismantle or exchange than single tubes.

In a preferred embodiment, an annular, oriented perpendicular to the central axis partition plate is inserted into the housing, which divides the cavity into two subspaces, and whose inner circle substantially coincides with the inner circle of the annular space, and whose outer circle radius is slightly less than the radius of the housing inner side , As a result, the two subspaces are fluidly connected to each other only by a lying in the inner circle of the partition plate and thus in the interior of the annulus passage. Advantageously, the supply lines and the discharge lines are each in different subspaces. The gaseous portion of the fluid flow can be performed in this way particularly favorable through the housing, being ensured that it flows through the annulus twice, namely once from outside to inside, and once from the inside to the outside. Since the partition plate in the radial direction does not extend to the inside of the housing, the condensate can flow away unhindered there.

With respect to the steam turbine plant, the above-mentioned object is achieved according to the invention by connecting the supply line or all supply lines of the above-described separation device to the steam outlet of the high-pressure turbine, and the discharge line or all discharge lines are connected to the steam inlet of the low-pressure turbine. Thus, the steam from the high-pressure turbine is introduced into the separation device, in which on the one hand, the water content is separated from the steam and on the other hand, the gaseous portion is overheated. The superheated steam is then introduced into the low-pressure turbine, where it is used for further energy production.

With regard to the method, the above-mentioned object is achieved according to the invention by passing the vapor emerging from the steam outlet of the high-pressure turbine into a cavity which is surrounded by a housing substantially rotationally symmetrical about a central axis, whereby the steam is set in rotation and its gaseous portion of liquid portion is separated and collected in an inner region of the cavity surrounded by the housing, and wherein the gaseous portion is heated by its passage in the inner region by heating elements and then supplied to the steam inlet of the low-pressure turbine.

In a preferred version of the method, at least some of the heating elements are tubular, thus forming heating pipes. The live steam generated by a steam generator is directed into at least some of the heating tubes, whereby the gaseous portion of the fluid flow introduced into the separator is heated or overheated. Alternatively or in combination, the high-pressure turbine bleed steam can be removed, which is then passed into at least some of the heating elements. In this way, in particular a two- or multi-stage overheating of the gaseous portion of the fluid stream can be achieved.

The advantages achieved by the invention are in particular that by a clever arrangement of heating elements within a cyclone separator, a separation of a heavy component or a liquid phase of a multi-phase fluid flow with simultaneous heating or overheating of the gaseous portion of the fluid flow in extremely space-saving and material and construction costs can be realized gentle way. As a result, the device is particularly suitable for use in systems that must be built in a small space. For the primary separation of the heavy component or phase of the fluid flow while the cyclone principle is used. The installation of additional fine separators allows a further reduction of the heavy component. The flow of the heating elements, which are designed for heating or overheating of the light phase of the fluid flow can be further improved by the use of baffles, vanes or pinhole.

A steam turbine plant in which such a separation device is connected between a high-pressure turbine and low-pressure turbine can be realized in a particularly compact and material-saving design. In this case, the device can be mounted substantially in a vertically positioned housing directly under the high-pressure turbine, so that the gas from the steam outlet of the high-pressure turbine at the upper end of the housing can flow into the device. Through discharge lines at the bottom of the housing then the superheated steam of the low-pressure turbine can be supplied.

Fig. 1

vier verschiedene, aneinandergesetzte viertelkreisförmige Teilquerschnitte von vier verschiedenen möglichen Ausgestaltungen einer Vorrichtung zur Phasenseparation eines Mehrphasen-Fuidstroms mit einem im Wesentlichen um eine Mittelachse rotationssymmetrisch ausgestalteten Gehäuse, wobei die jeweilige Querschnittsebene senkrecht zur Mittelachse gewählt ist,

Fig. 2

einen Längsschnitt durch die linksseitige Hälfte einer Ausführungsform der Vorrichtung gemäß Fig.1,

Fig. 3

eine weitere Ausführungsform der Vorrichtung gemäß Fig. 1 im rechtsseitigen Längsschnitt,

Fig. 4

eine Mehrzahl von Heizelementen der Vorrichtung gemäß Fig. 1 bis Fig. 3 und von den Heizelementen zugeordneten Leitschaufeln, hier im Querschnitt mit Blickrichtung in Richtung der Mittelachse dargestellt,

Fig. 5

einen Längsschnitt durch die linksseitige Hälfte einer weiteren bevorzugten Ausführungsform der Vorrichtung gemäß Fig. 1, und

Fig. 6

ein schematisiertes Blockschaltbild einer Dampfturbinenanlage mit einer Hochdruckturbine, einer Niederdruckturbine, einem Frischdampferzeuger sowie mit einer Vorrichtung zur Phasenseparation eines Mehrphasen-Fluidstroms gemäß einer Ausführungsform nach Fig. 1 bis Fig. 5.

Various embodiments of the invention are explained below with reference to a drawing. In it show in a highly schematic representation:

Fig. 1

four different contiguous quarter-circular partial cross-sections of four different possible embodiments of a device for phase separation of a multi-phase fluid flow with a substantially rotationally symmetrical about a central axis designed housing, the respective cross-sectional plane is selected perpendicular to the central axis,

Fig. 2

a longitudinal section through the left-side half of an embodiment of the device according to Fig.1 .

Fig. 3

a further embodiment of the device according to Fig. 1 in the right-hand longitudinal section,

Fig. 4

a plurality of heating elements of the device according to Fig. 1 to Fig. 3 and guide vanes associated with the heating elements, here shown in cross-section as viewed in the direction of the central axis,

Fig. 5

a longitudinal section through the left half of another preferred embodiment of the device according to Fig. 1 , and

Fig. 6

a schematic block diagram of a steam turbine plant with a high-pressure turbine, a low-pressure turbine, a fresh steam generator and with a device for phase separation of a multi-phase fluid flow according to an embodiment of Fig. 1 to Fig. 5 ,

Identical parts are provided with the same reference numerals in all figures.

In the Fig. 1 A device 1 for phase separation of a multiphase fluid flow shown comprises a housing 2, which is configured substantially symmetrically about a central axis M and has a hollow cylindrical shape and encloses a cavity 3 and into which four supply lines 6 are embedded. Each quadrant corresponds to the Fig. 1 a possible embodiment of the device, wherein in reality in each case all four quadrants are realized in one of the four ways shown here. The housing 2 has a diameter of about 6 meters in a preferred embodiment.

The multiphase fluid flow (not shown) flows in the inflow direction 10 substantially tangentially to the housing inner side 11 in the cavity 3 surrounded by the housing 2. By way of example, the fluid stream may be steam which is conducted from the steam outlet of a high-pressure turbine installed in a steam turbine plant through the supply lines 6 into the housing 2 of the device 1. The housing 2 is preferably made of steel or stainless steel, and depending on the field of application, other materials may be advantageous.

The fluid flow is thereby set in rotation, wherein the force acting on the fluid flow centrifugal force pulls the heavy component of the fluid flow, in this case water, to the outside of the housing inner side 11. The gaseous portion of the fluid flow moves due to the forming in the cavity 3 flow conditions of the inflow 12 into the annular space 14. The annular annular space 14 encloses the lying inside the housing 2 cylindrical outflow chamber 16 a spatially. In the annular space 14 are heating elements which are designed in terms of their heating power for overheating of the gaseous portion of the fluid stream arranged. In this case, individual heating pipes 18 can be used, which in a sense form ring bundles in their entirety. With a length of the tubes used in the ring bundle of about 13 m and a housing diameter of 6 m are at an outer diameter of the bundle of about 3.5 m and a tube diameter of about 2.3 cm with a total number of about 5000 Pipes approximately 16,000 m ² heating surface available. Alternatively or in combination with the heating tubes 18, individual bundles 20 can be used. The heating tubes 18 or individual bundles 20 are flown in the flow direction 22 of the gaseous portion of the fluid stream. The gaseous fraction is overheated in the annular space 14, whereupon it continues to flow into the outflow space 16. From there he will through discharge lines 24 (in Fig. 1 not shown) in the low-pressure turbine forwarded.

With a direct flow of the heating elements through the fluid flow, a separation efficiency of the water of up to about 80% can be achieved on the basis of previous experience. This means that the steam flowing in the heating tubes 18 or individual bundles 20 still has about 2.6% water content. In order to further reduce the water content if necessary, 12 fine separator 28 may be mounted in the inflow space. As a fine separator 28, for example, differently configured sheets can be used. It is also possible to use so-called fin separators. Another alternative consists of packets of corrugated sheets. Usually these separation elements are fastened or anchored in a frame. With the aid of the fine separator 28, the water content can be reduced to about 0.5% to 1%. However, with the introduction of the fine separator 28 in the inflow 12 is accompanied by a pressure drop and the inflow 12 is reduced. In the exemplary embodiment, the fine separator 28 are arranged on a lying around the central axis M outer circle with about 4m diameter and provide a flow area of about 70 m ² ready.

Taking into account the overall energy balance of the device 1, the additional used heat caused by the increased water content of about 2.6% (without fine separator 28) compared to 0.5 to 1% (with fine separators 28) at the entrance of the tube bundle would probably be negligible by eliminating the pressure drop caused by the fine separators 28. The energy balance results as follows: In order to come at a water content of 2.6% on the same outlet pressure and the same outlet temperature of the steam at the discharge line 24 as with a water content of 0.5 to 1%, about 20% more live steam be tapped from the main steam line or from the high-pressure turbine and introduced into the heating tubes. However, if the tube-side mass flow through the heating tubes remains the same, the outlet temperature drops by approx. 20 K due to the approx. 2% higher water content. Per Kelvin temperature loss, the generator output in a typical power plant turbine drops by approx. 0.2 MW _e (megawatt electric) , On the other hand, one obtains 10 MW _e of generator power per bar less pressure loss. An outlet temperature loss The superheated steam of about 20 K can thus be compensated by reducing the outlet pressure loss of about 400 mbar.

In order to improve the flow of the heating elements or to reduce or completely exclude the tangential component of the flow velocity, baffles 32, perforated plates 34 and vanes 36 may be arranged in the inflow 12. By this deflection, however, the inflow space 12 is reduced in size. Baffles 32, perforated plates 34 and vanes 36 may be used in the device 1 each alone or in different combinations with each other.

As heating elements tube bundles can be used as they u.a. used in heat exchangers. In order to provide the largest possible heating surface, it is possible to use finned tubes or slotted finned tubes. It can also be used - optionally in combination with these - smooth tubes. The tubes are flowed through, for example, by live steam at about 70 bar and / or - in multi-stage heating - from tapping steam of the high-pressure turbine at about 30 bar. The heating tubes 18 preferably have on the outside of a round cross-sectional profile in order to oppose the flow of fluid to be heated as little as possible flow resistance.

The device 1 is in Fig. 2 shown in a left-side longitudinal section in a possible embodiment. In this embodiment, the housing 2 of the device 1 is set up substantially vertically. The housing 2 is designed substantially hollow cylindrical and rotationally symmetrical about the central axis M. In the annular space 14 heating tubes 18 are mounted in the form of a ring bundle. To overheat the gaseous fraction of the heating tubes 18 live steam is supplied through the live steam supply line 38. At about half the height of the housing 2, the cavity 3 is divided by a horizontally oriented annular partition plate 37 into an upper and a lower subspace. The partition plate 37 extends in the radial direction from the inner diameter of the annular space 14 or ring bundle almost to the housing inner side 11. The upper and the lower subspace are in this way fluidly only via the lying within the partition plate 37 connecting portion the outflow space 16 is connected. This version can (at least in the upper subspace) with all four in Fig. 1 variants are combined.

The heating tubes 18 may be performed by the partition plate 37 and extend over both subspaces. Alternatively, in particular in two-stage heating, two groups of heating tubes 18, namely a group in the upper compartment and a group in the lower compartment, can be used. The heating tubes 18 of the two groups can be designed for different heating outputs.

The steam emerging from the high-pressure turbine is conducted through the supply lines 6 into the housing 2 in the upper subspace and flows in the housing inner side 11 in the tangential direction. Here, the water content of the vapor is deposited on the inside of the housing 11. Due to the forming in the cyclone flow conditions and optionally with the help of baffles 32, vanes 36 and perforated plates 34, the gaseous portion of the vapor flows into the discharge chamber 16 and passes through the located in the interior of the partition plate 37 transition to the lower subspace. The gaseous portion changes its direction after passing through the transition and is again directed outward through the annular space 14 in the direction of the inside of the housing 11, whereby a renewed heating takes place through the heating pipes 18 arranged in the annular space 14. Subsequently, the heated, gaseous fraction flows into the discharge lines 24, which are attached laterally to the housing 2, and further into the low-pressure turbine.

Since the partition plate 37 does not reach all the way to the inside of the housing 11, but instead there remains an annular gap, the condensate flowing down the inside of the housing 11, here water, can enter the condensate outlet 42 in the lower partial space. In addition, a second condensate drain 43 is provided in the recessed bottom region of the housing 2, via which the condensate collecting in the lower subspace can drain through a condensate drain 46.

A further embodiment of the device 1, which can be combined with the embodiments shown so far, is in Fig. 3 to see. Again, the central axis M of the housing 2 is oriented substantially vertically. The supply lines 6 open in the housing 2 such that the fluid flow flows with a gradient of about 15 °, the inside of the housing 2. As a result, the turbulent flow in the interior of the cavity is superimposed on a downwardly directed velocity component, which goes beyond the force of gravity, whereby the desired, essentially spiral or helical, flow guidance is supported.

In addition, at the in Fig. 3 variant shown in the inflow 12 for the enhanced separation of water fine separator 28 attached. The condensate collecting in the fine separators 28 is passed through a fine separator condensate discharge line 50 into the condensate outlet 42. The condensate, in this case water, is directed out of the housing by the condensate drains 46.

One possible embodiment of the optionally provided guide vanes 36 is shown in FIG Fig. 4 shown in a cross section. The selected cross-sectional plane is perpendicular to the central axis M of the device 1. The guide vanes 36 are mounted between an imaginary inner border 54 and an outer border 58. The borders 54 and 58 are in reality circular, but in the quite schematic and not true to scale Fig. 4 is not recognizable. The guide vanes 36 have a curved profile tapering in the direction of the heating tubes 18 (only the outer heating tubes 18 of the ring bundle surrounded by the guide vanes 36 are shown). The vanes 36 affect the flow direction 22 of the fluid flow. By suitable shape and positioning of the guide vanes 36 can be achieved that the heating tubes 18 are flowed substantially frontally. A tangential or oblique flow of the heating tubes 18 can be greatly reduced or avoided.

In the Fig. 5 illustrated embodiment of the device 1 with a substantially vertical orientation of the central axis M is designed for a two-stage heating or overheating of the fluid flow. For this purpose, a group of heating tubes 18 located in the outer region of the annular space 14 is supplied with a bleed steam taken from a bleed steam, for example a high-pressure turbine, at about 30 bar via a bleed steam feed line 40. An internal group of heating tubes 18 is fed via the live steam supply 38 live steam at about 70 bar. The forming in the annular space 14 condensate can be derived from the device 1 via the condensate drains 46. Between the inlet headers for the supplied with different steam groups of heating tubes 18 separating plates 82 may be provided for the separation of the respective vapors. This also applies to the exit collector.

Of the fluid flow flowing through the supply line 6 into the housing 2, the proportion of water is deposited on the inside of the housing 11 and possibly additionally on fine separators 28 arranged in the inflow space 12, while the gaseous portion flows into the annular space 14. The gaseous fraction flows around the outer group of heating tubes 18 supplied with bleed steam and then, on its way into the interior of the outflow space 16, around the inner group of heating tubes 18. The gaseous fraction is thus heated successively on its way into the interior of the discharge space 16. This type of two-stage heating can be generalized to multi-stage heating with the aid of additional steam feeds and tube groups in an obvious manner. Furthermore, this form of two-stage or multi-stage heating with the variant in which viewed in the direction of the central axis M of the housing 2 a plurality, designed for different heating power groups of heating tubes 18 behind or are arranged one above the other, combined.

In the in Fig. 5 shown variant of the device 1 leads the discharge line 24 in the vertical direction down from the discharge chamber 16 out. This embodiment of the discharge line 24 and the associated, vertically downward discharge of the heated steam can also be combined with a single-stage heating.

An advantageous embodiment of a steam turbine plant 62 is in Fig. 6 shown. It comprises a main steam generator 66, a high-pressure turbine 70, and a low-pressure turbine 74. The device 1 is connected on the flow side between the high-pressure turbine 70 and the low-pressure turbine 74. The live steam generated in the main steam generator 66 is directed to perform work in the high pressure turbine 70. By doing work, the steam in the high pressure turbine 70 relaxes, increasing its water content. So that the steam in the low-pressure turbine 74 can be used as efficiently as possible for energy production, it must be prepared in a suitable manner. For this purpose, its water content must be reduced, before it is subsequently transferred to a superheated state. For this reason, the steam exiting the steam outlet of the high-pressure turbine 70 is conducted via a distributor through supply lines 6 into the housing 2 of the device 1. There, the steam flows tangentially to the housing inner side 11 and is thereby set in rotation. The gaseous portion of the steam flows into the housing interior, where it is put into a superheated state by heating elements, in particular heating pipes. From there, the superheated steam is passed through discharge lines 24 into the steam inlet of the low pressure turbine 74. There, the processed in this way steam can be further used for energy. The heating tubes (not shown here) of the device 1 are supplied in this embodiment by the heating supply line 78 with live steam from the steam generator 66. Alternatively or additionally, the high pressure turbine 70 could be removed for this purpose bleed steam.

The device 1 is of course not limited to use in steam turbine plants. It can essentially always be used where the heavier component or phase is to be separated from a multiphase fluid stream and the gaseous fraction is to be heated or superheated. The heavy component of the fluid stream can be water as explained above. However, applications are also conceivable in which the heavy component consists of solid particles. This could be, for example, soot or dirt particles.

LIST OF REFERENCE NUMBERS

1 contraption M central axis 2 casing 3 cavity 6 supply line 10 inflow 11 Housing inside 12 inflow 14 annulus 16 outflow 18 heating pipe 20 Single bundle 22 flow direction 24 discharge line 28 fine separator 32 baffle 34 perforated sheet 36 vane 37 separating plate 38 Live steam supply line 40 Anzapfdampfzuleitung 42, 43 condensate drain 46 condensate drainage 50 Feinabscheiderkondensatableitung 54 inner border 58 outer border 62 steam turbine plant 66 Live steam generator 70 High-pressure turbine 74 Low-pressure turbine 78 Heizzuleitung 82 Divider

Claims (19)

1. A device (1) for phase separation of a multi-phase fluid flow, having a housing (2) substantially configured rotationally symmetrically around a central axis (M) and enclosing a hollow space (3), having at least one inlet line (6) for the fluid flow, which is designed for an inflow of the fluid flow oriented substantially tangential to the inner surface (11) of the housing, and having at least one outlet line (24) for the separated gaseous part of the fluid flow, characterized in that heating elements designed for heating the gaseous part are arranged inside the hollow space (3) in an annular space (14) situated concentrically around the central axis (M).
2. The device (1) of claim 1, wherein the annular space (14) with the heating elements is configured for a through-flow of the gaseous part of the fluid flow and divides the hollow space (3) into an inflow space (12) situated between the inner surface (11) of the housing and the annular space (14) and an outflow space (16) situated inside the annular space (14).
3. The device (1) of claim 1 ou 2, wherein the housing (2) is substantially designed as a hollow cylinder.
4. The device (1) of any of claims 1 to 3, with a substantially vertical orientation of the central axis (M).
5. The device (1) of any of claims 1 to 4, wherein the heating power of the heating elements is designed for overheating the gaseous part of the fluid flow, in particular water vapor.
6. The device (1) of any of claims 1 to 5, wherein the or each inlet line (6) is configured such that the velocity vector of the fluid flow flowing into the hollow space (3) includes a component in the direction of the central axis (M) of the housing (2).
7. The device (1) of claim 6, wherein the respective inlet line (6) is configured such that the velocity vector of the fluid flow flowing into the hollow space (3) is inclined by 10 to 30 degrees, in particular 15 degrees, relative to a plane perpendicular to the central axis (M).
8. The device (1) of any of claims 1 to 7, with four inlet lines (6) distributed uniformly over the circumference of the housing (2).
9. The device (1) of any of claims 2 to 8, wherein directional baffles (32) and/or guide blades (36) are arranged in the inflow space (12), which direct the gaseous part of the fluid flow into the annular space (14).
10. The device (1) of any of claims 2 to 9, wherein fine separators (28) are arranged in the inflow space (12), and wherein a fine-separator condensate discharge line (50) is placed in the inflow space (12), through which the condensate accumulating in the fine separator (28) during operation is discharged from the hollow space (3).
11. The device (1) of any of claims 1 to 10, wherein two or more groups of heating elements are arranged one behind the other in the annular space (14), viewed in the direction of the central axis (M), whose heating elements are each designed for different heating powers.
12. The device (1) of any of claims 1 to 11, wherein the heating elements are configured in the shape of tubes and are designed for being flown through by a fluid heating medium, in particular water vapor.
13. The device (1) of claim 12, wherein each of the heating elements is configured as a straight tube oriented parallel to the central axis (M).
14. The device (1) of claim 12 or 13, wherein in each case several heating elements which are adjacent to each other are combined in one bundle.
15. The device (1) of any of claims 1 to 14, wherein a ring-shaped separating plate (37), oriented vertical to the central axis (M), is placed in the housing (2) and divides the hollow space (3) into two partial spaces and whose inner circle substantially coincides with the inner circle of the annular space (14) and whose outer-circle radius is smaller than the radius of the inner side (11) of the housing.
16. A steam-turbine installation (62) with a high-pressure turbine (70) and a low-pressure turbine (74) and a device (1) according to any of claims 1 to 15, wherein the at least one inlet line (6) is connected with the steam outlet of the high-pressure turbine (70) and wherein the at least one outlet line (24) is connected with the steam inlet of the low-pressure turbine (74).
17. A method for operating a steam-turbine installation (62) with a high-pressure turbine (70) and a low-pressure turbine (74), wherein the steam flowing out of the steam outlet of the high-pressure turbine (70) is directed into a hollow space (3) enclosed by a housing (2) which is substantially rotationally symmetrical around a central axis (M), whereby the steam is rotated and its gaseous part is separated from the liquid part and is collected in an inner area of the housing (2), characterized in that the gaseous part is heated by means of heating elements upon its entry into the inner area and is then fed to the steam inlet of the low-pressure turbine (74).
18. The method of claim 17, wherein at least some of the heating elements are configured in the shape of tubes and are flown through by live steam generated in a steam generator (66).
19. The method of claim 17 or 18, wherein at least some of the heating elements are configured in the shape of tubes and wherein extraction steam is taken from the high-pressure turbine (70) and is directed into these heating elements.

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