DE102016113007B4 - Return arrangement and method of return - Google Patents

Abstract

Return arrangement (6) for returning at the output of a downstream of a turbine, (4) connected capacitor (5) condensate back to the input of a steam generator (2) in a steam power plant, characterized by a branch line (7) for branching a branch flow between the steam generator (2) and the turbine (4), at least one intermediate storage tank arrangement (9, 10, 11, 20, 41) for receiving a buffer storage volume (18) of condensate with at least one condensate outlet opening (95, 105, 115, 26, 34, 57, 65 ) for discharging condensate, and means (92, 102, 112, 25A, 33, 52, 60) for establishing an operative connection between the branch line (7) and the temporary storage container arrangement (9, 10, 11, 20, 41) to communicate over the Condensate outlet opening (95, 105, 115, 26, 34, 57, 65) Conveying condensate out of the intermediate storage container arrangement (9, 10, 11, 20, 41), wherein the intermediate storage container arrangement (9, 10, 11, 20, 41) 41) via the Kondensatauslassöffnung (95, 105, 115, 26, 34, 57, 65) with the steam generator (2) is arranged connectable.

Description

The present invention relates to a return arrangement for returning condensate arising at the outlet of a condenser connected downstream of a turbine back to the entrance of a steam generator in a steam power plant.

The present invention also relates to a method of recycling condensate accumulating at the outlet of a condenser connected downstream of a turbine back to the entrance of a steam generator in a steam power plant.

A steam power plant has as a core component to a heat source, which is generated in an evaporator water vapor at high pressure. The steam is used to generate electrical energy, usually by supplying it to a turbine and driving it. At the low-pressure outlet of the turbine, the steam is fed to a condenser, where it is cooled by suitable cooling, for example by river water, until condensation. In order to close the steam cycle, the generic forming return arrangement is now used to guide the condensate from the outlet of the condenser back to the evaporator, where by heating steam from the condensate is generated again.

Conventionally, the return arrangement is designed in the form of feedwater pumps. However, a disadvantage of the use of feedwater pumps for returning the condensate is their comparatively high energy requirement, which reduces the efficiency of the steam power plant. Another disadvantage of feedwater pumps as feedback arrangement according to the prior art is to be mentioned that these may be maintenance-intensive as rotating components under certain circumstances.

Accordingly, with respect to the generic method in the prior art, the condensate produced at the outlet of the condenser connected downstream of a turbine is fed by means of a feedwater pump back to the inlet of the steam generator, which has the aforementioned disadvantages.

The DE 10 2013 013 104 B4 makes a heat engine previously known, in which a steam generator via a high pressure vessel and low pressure vessel drives a turbine, wherein residual steam is fed to a condenser and the condensate is fed by means of a vacuum pump via a feedwater line to the steam generator.

From the DE 29 07 068 A1 is a method for bridging load fluctuations of an electrical supply network by means of a main circuit of a thermal power plant associated thermal storage and a device for performing the method previously known. In the previously known method and the prior art device, a condensate pump or a low-pressure feed pump are used to return condensate to a steam generator.

The DE 20 2009 003 297 U1 makes a device for converting thermal energy into mechanical energy previously known, in which in a so-called thermodynamic gravity storage liquid refrigerant is vaporized in an evaporator, is then condensed and realized via a regenerative device, which includes auxiliary pistons driven in cylinders movable piston, a condensate return ,

The EP 1 806 533 A1 makes a steam cycle of a power plant previously known, in which a condensate collection and return line is provided between a superheater and a steam generator to pump using appropriate pumps condensate directly back into the associated evaporator.

From the US 4,164,848 For example, a method and a device for covering peak loads and as a failure reserve in steam power plants are known, wherein a turbine is driven by steam generated in a steam generator and at the low pressure end of the turbine resulting condensate is returned via feedwater pumps to a steam generator.

Against the background outlined, the present invention is based on the object of providing a return arrangement of the type mentioned at the outset, as well as a method for returning the aforementioned type, which work with the lowest possible energy input in order to increase the efficiency of the steam power plant, and which without rotating Work components.

According to the invention, this object is achieved by a return arrangement of the type mentioned, which has a branch line for branching a branch flow between the evaporator and the turbine, at least one intermediate storage tank arrangement for receiving a buffer storage volume condensate with at least one Kondensatauslassöffnung for discharging condensate and means for establishing an operative connection between the Branch line and the intermediate storage tank arrangement to convey out through the opening condensate from the intermediate storage tank arrangement, wherein the intermediate storage tank arrangement is arranged connectable via the Kondensatauslassöffnung with the evaporator. According to the invention it is thus proposed to effect the condensate recirculation without the use of feedwater pumps using the energy of the branched off branch stream.

By means of suitable valves, according to the invention, a buffer storage volume condensate is built up in the intermediate storage tank arrangement and subsequently pressed out of the intermediate storage tank arrangement via the branched off branch stream in order to be supplied to the evaporator. The advantage is that feedwater pumps with rotating components for the return of the condensate to the steam generator can be omitted. In addition, with the return arrangement according to the invention, the return of the condensate to the steam generator can be effected more energy-efficiently than when using conventional feedwater pumps. Accordingly, the overall efficiency of a power plant improves as well as the CO ₂ balance with advantage according to the invention. Depending on which pressure conditions prevail in the field, for example taking into account pressure losses, and depending on the differences in height between the intermediate storage tank arrangement and the evaporator inlet, it will be necessary within the scope of the invention to use a forced pump to remove the condensate from the intermediate storage tank arrangement to the evaporator recirculate. For example, if the evaporator is placed above the height of the condenser, the condensate water must be conveyed by a forced pump to overcome the difference in elevation. The same applies to overcoming unavoidable flow losses and mass accelerations from condensate water in the pipelines. However, the energy required for the pump according to the invention called forced pump is low in comparison to that of a conventional feedwater pump, since there are equal pressure conditions in front of and behind the pump. The forced pumps must therefore apply in the invention advantageously only any height differences, flow losses and mass accelerations or overcome.

In an embodiment of the return arrangement according to the invention several, preferably two, in particular three, intermediate storage container arrangements are provided. This achieves the advantage that a continuous or quasi-continuous condensate return to the steam generator is possible. Because with a suitable control and corresponding valves, in the case of two intermediate storage container arrangements, the return arrangement according to the invention can be operated such that, while a temporary storage container assembly is filled with condensate to build up the intermediate storage volume, the other intermediate storage container assembly is emptied by means of the branched branch stream in the direction of the steam generator. In this way, it is advantageously ensured that feedwater, ie condensate, is returned to the steam generator continuously and according to the power requirement.

When using a third intermediate storage container arrangement according to the invention, the continuous recycling of condensate in conjunction with a suitable controller and corresponding valves can still be improved. After emptying the buffer storage volume from one of the intermediate storage tank arrangements, the steam used for emptying the intermediate storage volume is at a significantly higher pressure and energy level than at the outlet of the condenser. Therefore, a relaxation of the intermediate storage tank assembly is mandatory before a re-filling with condensate can be done without pumps. Characterized in that according to the preferred embodiment of the invention described here, a third intermediate storage container arrangement is provided, the pressure compensation can be carried out in such a way that the residual energy contained is also converted into electrical energy. If this relaxation process is carried out in a third intermediate storage tank arrangement, in the interests of a continuous condensate return, the two other intermediate storage tank arrangements can be filled with condensate in parallel or emptied.

In an advantageous embodiment of the invention, the at least one intermediate storage container arrangement on two materially separate subvolumes, which are in pressure communication with each other. Whereas the principle of the return arrangement according to the invention is also applicable, if the branched branch stream can be guided directly to the intermediate storage volume accommodated in the intermediate storage tank arrangement in order to drive it out, energy losses can result. Because at the interface between the branch stream and the Intermediate storage volume condensate, for example, a heat transfer. Due to the heat transfer, a lesser proportion of the energy of the branch stream is available for mechanically draining the intermediate storage bin arrangement. In this regard, the proposed in this embodiment of the invention separation into two materially separate subvolumes, one of which is filled with the branched branch stream and the other subvolume is filled with condensate, advantageous. Decisive for the inventive principle of the feedback, however, is the pressure connection between the sub-volumes, so that the pressure in the sub-volume acted upon by the branch flow can contribute to the emptying of the partial volume containing the condensate.

In particular, in a preferred embodiment of the return arrangement according to the invention, the intermediate storage container arrangement can have a piston-like separating element in order to separate the partial volumes from one another. The intermediate storage container arrangement can thus comprise, for example, a container for receiving the intermediate storage volume, which is divided by a piston into two partial volumes. The piston can be provided with heat-insulating material. Similar to a membrane of the piston according to the invention exposed on both sides of the piston to the pressure prevailing in the two sub-volumes pressure conditions.

In a further development of the return arrangement according to the invention, the intermediate storage container arrangement has two partial containers each provided with a piston-like separating element, the dividing elements of each partial container being mechanically coupled to one another. This embodiment allows a further improvement of the continuous condensate return. Because in conjunction with suitable valves and inlet and outlet lines one of the sub-containers can be filled or emptied exclusively with condensate, the other sub-container exclusively receives the diverted via the branch line branch stream or the residual pressure after emptying the condensate-carrying sub-container, optionally below Utilization of the residual energy, to be relaxed. The mechanical coupling of the piston-like separating elements can be realized for example by a rigid rod-like connection, which ensures that displacements of the piston in the steam cylinder forcibly lead to displacements of the piston in Kondensatzylinder. For this purpose, according to the invention, each sub-tank in each sub-volume defined by the separating element can have an inlet or outlet for condensate water or the branch stream. The connection between the separating elements, ie in particular the piston, can be designed as a lifting or push rod.

In an advantageous embodiment of the invention, a pressure application surface of the separating element between the two sub-containers is designed differently. In this way, according to the invention results in a "surplus force", for example, on the side of the steam cylinder. This force can be used for forcibly guided recirculation of the feed water and the overcoming of resulting friction / flow losses, so that the condensate return can be carried out entirely without a forced pump or the like.

In particular, according to the invention, the separating elements can be coupled by means of at least one lifting and / or push rod. The lifting or push rod can be connected perpendicular to the end face of the piston-like separating element with this. If the lifting or push rod within each sub-container has a different diameter, results in the same surface area of the end face of the separating elements a different pressure application surface with the above-mentioned advantageous effects.

In order to further improve the energy efficiency, in a preferred embodiment of the return arrangement according to the invention, a secondary steam circuit for recirculation via the branch line branched medium may be provided in the condenser, which comprises the branch line, at least one of the intermediate storage tank arrangements and a return line connecting the intermediate storage tank arrangements with an inlet of the condenser. Since the partial steam is still at a higher pressure level than at the outlet of the condenser after use of the branched off branch stream for conveying a buffer storage condensate to the steam generator, the secondary steam circuit according to the invention can proceed to transfer the branched branch flow to the condenser inlet. The branched off branch thus passes bypassing the turbine of the steam power plant from the steam generator via one of the intermediate storage tank and the secondary steam cycle to the condenser.

In particular, in this context, it is advantageous according to the present invention for the secondary steam cycle to include means for converting the energy and / or pressure reducing agent contained in the secondary steam cycle to reduce the pressure in the secondary Steam circuit has flowing media. In particular, a turbocharger may be provided in the secondary steam cycle to generate further electrical energy from the remaining overpressure of the branched branch stream before the secondary steam cycle discharges into the condenser. Alternatively or additionally, a suitably designed throttle can be used to reduce the pressure before the secondary steam circuit opens to the inlet of the condenser.

When operating the return arrangement, in which the intermediate storage container arrangement has two partial containers each provided with a piston-like separating element, wherein the dividing elements of each partial container are mechanically coupled to one another, a partial volume of the steam cylinder can be acted upon by the branched branch stream. As a result, the separating piston is displaced in the steam cylinder, wherein in the other partial volume of the steam cylinder which is acted upon by a residual pressure partial steam volume is expelled, for example in the direction of the secondary steam cycle. Due to the coupling of the separating piston, the movement of the separating piston in the steam cylinder also causes a movement in the condensing cylinder. This movement of the separating piston in the condensing cylinder can, in turn, simultaneously cause the partial volume already filled with condensate to be emptied in the direction of the steam generator and the other partial volume to be filled with condensate from the condenser. After relaxing the communicating with the branch line sub-volume in the steam cylinder, the reverse admission of the other sub-volume of the steam cylinder with the branched branch stream and with appropriate switching of the valves, the function of the sub-volumes in the steam cylinder or Kondensatzylinder reverses.

• - zwischen dem Verdampfer und der Turbine ein Abzweigstrom abgezweigt wird,
• - ein Zwischenspeichervolumen Kondensat zwischengespeichert wird,
• - das zwischen Speichervolumenkondensats mittels des Abzweigstroms zum Verdampfer entleert wird.

The method task is solved with a generic method with the features of claim 10, in which in particular

• - a branch stream is branched off between the evaporator and the turbine,
• a buffer storage volume condensate is temporarily stored,
• - Which is emptied between storage volume condensate by means of the branch stream to the evaporator.

In this way, according to the invention, the energy of the branched off branch stream is advantageously used to return the condensate. In this case, rotating parts, such as a feedwater pump, eliminated and the operation is particularly energy efficient possible.

Advantageous embodiments of the method according to the invention are listed in the dependent claims 11 to 14.

In an advantageous embodiment of the method according to the invention, a residual energy of the branch stream is used for converting into mechanical and / or electrical energy after supplying the intermediate storage volume condensate by means of the branch stream. The energy efficiency of the method according to the invention can thus be further increased with advantage.

In particular, the method according to the invention is carried out with a return arrangement according to one of claims 1 to 7.

The invention will be described by way of example in a preferred embodiment with reference to a drawing, wherein further advantageous details are shown in the figures of the drawings.

Functionally identical parts are provided with the same reference numerals.

• 1: schematische Darstellung eines Dampfkraftwerks mit einer erfindungsgemäßen Rückführungsanordnung in einer bevorzugten Ausführungsform;
• 2: schematische Darstellung einer Zwischenspeicherbehälteranordnung als alternativer Bestandteil einer Rückführungsanordnung gemäß der Erfindung in bevorzugter Ausgestaltung zur Veranschaulichung der Wirkungsweise in einem Zustand (a) im Takt I, (b) im Takt IA sowie (c) im Takt IB, (d) in einem Takt 2, (e) in einem Takt 2(a) sowie in (f) in einem Takt 2B;
• 3: schematische Darstellung einer alternativen Ausgestaltung einer Zwischenbehälteranordnung als Bestandteil einer bevorzugten Ausgestaltung einer Rückführungsanordnung in verschiedenen Betriebszuständen, wobei in (a) der Betriebszustand in einem Takt I, in (b) der Betriebszustand in einem Takt IA, in (c) ein Takt IB sowie in (d) ein Zustand in einem Zwischentakt IIA gezeigt ist.

The figures of the drawings show in detail:

• 1 : schematic representation of a steam power plant with a return arrangement according to the invention in a preferred embodiment;
• 2 : Schematic representation of a buffer storage arrangement as an alternative component of a return arrangement according to the invention in a preferred embodiment for illustrating the mode of operation in a state (a) in the clock I, (b) in the clock IA and (c) in the clock IB, (d) in one clock 2, (e) in a clock 2 (a) and in (f) in a clock 2B;
• 3 : schematic representation of an alternative embodiment of a tundish assembly as part of a preferred embodiment of a return assembly in different operating conditions, where in (a) the operating state in a cycle I, in (b) the operating state in a cycle IA, in (c) a clock IB and in (d) a state is shown in an intermediate clock IIA.

Referring to 1 is a schematic representation of a steam power plant 1 specified. The steam power plant 1 consists essentially of a steam generator 2 , a heat supply, not shown 3 with which the steam generator 2 for the purpose of generating steam, one from the steam generator 2 powered turbine 4 , one at the low pressure side of the turbine 4 switched capacitor 5 and a return arrangement according to the invention 6 , which clarify the system boundaries in the 1 surrounded by a dashed line.

In principle, the steam power plant 1 in the steam generator 2 by means of the heat supply 3 supplied energy generated steam, which at high pressure to the high pressure side of the turbine 4 is guided and this drives. At the low pressure side of the turbine 4 the steam gets into the condenser 5 introduced and at the output of the capacitor 5 is by means of the return arrangement 6 the condensate as feed water to the steam generator 2 fed and the circuit is closed.

The invention now relates to the return arrangement 6 , which takes the place of conventional feedwater pumps.

Essentially, the return arrangement according to the invention 6 from a branch line 7 which is from the high pressure line 8th , which is steam from the steam generator 2 to the turbine 4 leads, is branched off, and a first buffer tank 9 a second buffer tank 10 and a third buffer tank 11 , The cache containers 9 . 10 . 11 are identical. They each have a high pressure steam inlet 91 . 101 . 111 on, which in each case via a high-pressure inlet valve 92 . 102 respectively. 112 with the branch line 7 communicated. Furthermore, each temporary storage container 9 . 10 . 11 a condensate inlet 93 . 103 . 113 on, which in each case via a condensate inlet valve 94,104,114 with the condensate outlet 12 of the capacitor 5 communicated.

Further, each of the temporary storage tanks 9 . 10 . 11 a Kondensatauslass 95,105,115, which in each case via a Kondensatauslassventil 96,106,116 with a feedwater inlet of the steam generator 2 communicated.

Next is each buffer tank 9 , 10,11 provided with a residual steam outlet 97,107,117, which with a secondary steam cycle 13 communicated. The secondary steam cycle 13 flows into the secondary entrances 14 of the capacitor 5 ,

Finally, each of the intermediate storage containers 9, 10, 11 has a volume compensation opening 98 , 108.118, which in each case via a volume compensation valve 99,109,119 in the condenser 5 via the volume equalization line 12.1 is returned.

The secondary steam cycle 13 is above each of the temporary storage tanks 9 . 10 . 11 associated valves optionally via a turbocharger 15 or directly via the secondary input 14 in the condenser 5 recyclable.

In detail, the first buffer tank 9 associated with a bypass valve 1391, via which in the open state, a direct connection from the residual steam outlet 97 to the secondary entrance 14 can be produced. Next are the first buffer tank 9 a first turbocharger valve 1392 , a second turbocharger valve 1393 and an intermediate pressure reducer 1394 assigned.

Accordingly, the second buffer tank 10 a bypass valve 13101 assigned, via which in the open state, a direct connection from the residual steam outlet 107 to the secondary entrance 14 can be produced. Next are the second buffer tank 10 a first turbocharger valve 13102 , a second turbocharger valve 13103 and an intermediate pressure reducer 13104 assigned.

Analogously, the third buffer tank 11 associated with a bypass valve 13111, via which in the open state, a direct connection from the residual steam outlet 117 to the secondary entrance 14 can be produced. Further, the third buffer tank 11 a first turbocharger valve 13112 , a second turbocharger valve 13113 and an intermediate pressure reducer 13114 assigned.

The high pressure steam inlet valves 92 . 102 . 112 , the condensate inlet valves 94 . 104 . 114 , the condensate outlet valves 96 , 106, 116 and the volume compensation valve 99 . 109 . 119 are about one in 1 not shown control unit switchable.

The functioning of in 1 illustrated embodiment of a return assembly according to the invention 6 is explained below with reference to Table 1 and Table 2. With regard to Table 1, it should be noted that, for reasons of clarity, in addition to the valves 92 . 94 . 96 . 99 , 102, 104, 106, 109, 112, 114, 116, 119 and their positions, which are respectively labeled "OPEN" and "CLOSED", also indicate the states of the residual steam outlet 97 . 107 . 117 are drawn. The indication "CLOSED" means at one of the residual steam outlets 97 . 107 . 117 in that a connection to the secondary steam circuit 13 does not exist. The associated valve positions for the secondary steam circuit 13 are shown in Table 2. These are then all in the "CLOSED" state. Correspondingly, the indication "UP" means at one of the residual steam outlets 97 . 107 . 117 in that a connection to the secondary steam circuit 13 consists. The associated valve positions for the secondary steam circuit 13 are again shown in Table 2, which in each case one of the branches in the secondary steam cycle 13 is open.

1 now shows the return arrangement according to the invention 6 in a state where the first buffer tank 9 with at the condensate outlet 12 of the capacitor 5 accumulating condensate is filled, the second buffer tank 10 in the direction of the steam generator 2 is emptied and the third buffer tank 11 via the secondary steam circuit 13 is relaxed. This corresponds to the clock 1 according to table 1. For this is the condensate inlet valve 94 opened and also is the volume compensation valve 99 open. By contrast, the high pressure inlet valve 92 as well as with the residual steam outlet 97 within the secondary steam cycle 13 closed communicating valves. In 1 it can be seen that in the first buffer tank 9 a cache volume 16 Condensate is included and above a compensation volume 19 is present, which via the volume compensation opening 98 with open volume compensation valve 99 at the pressure level of the condenser 5 at the condensate outlet side 12 stands.

At the same time in the clock I, the second buffer tank 10 switched to emptying. The switching states of the valves of the inlet and outlet of the second intermediate storage container 10 are shown in Table 1 in the column to the clock I. The cache volume 18 which is in the second intermediate storage container 10 is stored, stands in operative contact with the high-pressure steam volume 17 above the buffer volume 18 , This will be the buffer volume 18 via the condensate outlet valve 106 to the steam generator 2 pressed to the manner of a pump, the return of the condensate outlet 12 of the capacitor 5 to obtain incurred condensate.

At the same time in the bar I, which in 1 is illustrated, the third cache container 11 switched to after expelling the previous clock in the third buffer tank 11 cached intermediate storage volume residual pressure remaining switched. The switching state of the third buffer tank 11 belonging valves 112 . 114 . 116 . 119 or the opening state of the residual steam outlet 117 is shown in Table 1 in the column of clock I. This will be the third temporary storage container 11 contained steam, which at a pressure level between that in the branch 7 and at the condensate outlet 12 stands, via the secondary steam cycle 13 to the condenser 5 via its secondary inputs 14 recycled.

For this purpose, further energy is first removed by the third intermediate storage tank 11 associated valve groups within the secondary steam cycle 13 are switched to the third buffer tank 11 with the turbocharger 15 communicate. After reaching a lower pressure value, a further relaxation of the third intermediate storage tank 11 existing residual vapor volume directly into the condenser 5 via its secondary inputs 14 causes by the third buffer tank 11 associated valve groups within the secondary steam cycle 13 be switched to the third buffer tank 11 directly, bypassing the turbocharger 15 , with the capacitor 5 connect to.

Thus, in the clock I at the same time a buffer storage volume 16 Condensate, which at the condensate outlet 12 of the capacitor 5 accumulates, accumulates, while in the second intermediate storage tank 10 accumulated condensate water with the aid of high-pressure steam, which via the branch line 7 is connected to the steam generator 2 is returned, while in the third buffer tank 11 residual energy contained in the secondary steam cycle 13 by means of the turbocharger 15 is further relaxed under energy.

After clock in the second buffer tank I 10 by expelling the buffer volume 18 Condensate is completely emptied, the clock II is initiated. The switching states of all valves, which are relevant in the clock II, are summarized in Table 1. Accordingly, this is now the clock in the first buffer tank 9 constructed buffer storage condensate 16 to the steam generator 2 dumped, the steam in the high-pressure steam volume 17 of the second buffer tank 10 is over the secondary steam cycle 13 relaxed and the third intermediate storage tank 11 will be filled. The emptying, relaxing or filling of the first intermediate storage container 9 , the second temporary storage container 10 or the third intermediate storage container 11 takes place as in the clock I with respect to the second intermediate storage container 10 , the third intermediate storage container 11 and the first intermediate storage container, respectively 9 described.

After completion of the clock II is in the first buffer tank 9 a high pressure steam volume having a residual pressure, as in the 1 shown state of the third temporary storage container 11 according to clock I. The second buffer tank 10 is at the completion of the clock II in a state to receive condensate from the condenser 5 , according to the in 1 State of the first temporary storage tank shown in clock I 9 , Finally, after completion of the clock II, the third buffer tank is located 11 in a state analogous to the state of the first buffer tank 9 according to the in 1 shown bar I.

Next, in clock III, the function of the buffer storage 9 , 10, 11 again shifted to the effect that the first buffer tank 9 is switched to relax, the second buffer tank 10 is switched to fill and the third buffer tank 11 is switched to empty. The corresponding switching states of the valves are shown in Table 1 in the rows to clock III. The processes for relaxing, filling or emptying the buffer tank 9 . 10 . 11 are analogous to those described above in connection with bars I and II.

In this way, the use of three buffer tanks 9 . 10 . 11 a quasi-continuous return from the condensate outlet 12 of the capacitor 5 accumulating condensate to the steam generator 2 causes. At best, an electric forced pump is required and comparatively little electrical energy must be added to the system. Rather, much of the energy required for recirculation is via the branch line 7 ultimately the steam generator 2 taken, with a recovery of energy through the secondary steam cycle 13 and the turbocharger contained therein 15 is provided. For this reason, forced pumps must advantageously apply or overcome only any height differences, flow losses and mass accelerations in the invention.

Table 2 illustrates in more detail how the cache bins 9 . 10 . 11 associated valves in the secondary steam circuit 13 be switched in detail to effect relaxation. Accordingly, the relaxation takes place in two stages. Each in buffer "relax" switched intermediate storage tank 9 . 10 . 11 is first by switching its associated bypass valve 1391 . 13101 . 13111 in the state "CLOSE" and switching the first turbocharger valve 1392 . 13102 . 13112 and second turbocharger valve 1393 . 13103 . 13113 in the "OPEN" state via the respectively assigned pressure reducer 1394 . 13104 . 13114 relaxed over the turbocharger. Then, after falling below a given pressure value, the first turbocharger valve 1392 . 13102 , 13112 and the second turbocharger valve 1393 . 13103 . 13113 switched to the "CLOSED" state and the associated bypass valve 1391 . 13101 , 13111 is switched to the "OPEN" state for a residual release directly to the secondary input 14 to effect.

At the in 1 described embodiment of a return assembly according to the invention 6 is in the cache containers 9 . 10 . 11 when emptying a direct contact between the high pressure steam volume 17 and the buffer volume 18 which is about the high pressure steam volume 17 is expelled from the respective intermediate storage container provided. This may be undesirable under certain circumstances, for example because a heat transfer takes place at the boundary layer, which results in less energy for expelling the intermediate storage volume 18 is available.

An improvement of the invention therefore arises when at least one of the intermediate storage container as in the 2 (a) to 2 (f) illustrated is designed. The 2 (a) to 2 (f) show an alternative embodiment of a buffer tank 20 as part of an embodiment of a return arrangement according to the invention 6 ,

It shows 2 (a) a state of the alternative surge tank 20 in which it is emptied, as in 1 the second buffer tank 10 , In each of the part 2 (a) to 2 (f) are made For reasons of clarity of presentation only the unlocked inlets, outlets and associated valves or valve groups shown. Constructively, the expansion tank 20 according to the second embodiment, however cumulatively all in the 2 (a) to 2 (f) shown inlets, outlets and valves or valve groups on.

As in 2 (a) to recognize, has the buffer tank 20 a freely displaceable in the axial direction of the container piston 21 on which the buffer tank 20 in two sub-volumes 22 . 23 divides which over the piston 21 in a pressure connection with each other. This is a high pressure steam inlet 24 via a high pressure steam inlet valve 25A unlocked to the branch line 7 to communicate. The second partial volume 23 of the temporary storage tank 20 is doing with a high pressure steam volume 17 filled, which is the piston 21 pushes to the left and in this way that in the first subvolume 22 contained caching volume 18 Condensate through a condensate outlet and an open condensate outlet valve 26A to the steam generator 2 casts.

In the in 2 B) shown state, which substantially the state of the third temporary storage container 11 in the 1 illustrated state according to clock I, is the second partial volume 23 due to the displacement of the piston 21 and the associated expulsion of the first sub-volume 22 so that it covers the entire volume of the temporary storage tank 20 fills. It is filled with high pressure steam, like the second buffer tank 10 according to 1 , In this state, the in the second subvolume 23 contained steam via a first residual steam outlet 27 the secondary steam cycle 13 fed. In principle, the high pressure steam volume 17 to the compensation volume 19 , after over the valves 1392 and 1393 over the turbocharger 15 the high pressure is reduced. Subsequently, via the bypass valve 1391 the pressure in the compensation volume 19 via the secondary input 14 to the capacitor 5 issued.

In 2 (c) is illustrated as the cache container 20 with at the condensate outlet 12 of the capacitor 5 accumulating condensate is filled. This is done via a first condensate inlet 28 , which via a first condensate inlet valve 29 with the capacitor 5 communicates condensate in the second part volume 23 filled. At the same time, there is a volume compensation opening 30 and an associated volume balance valve 31 via the volume equalization line 12.1 a pressure equalization with the condenser 5 created.

After the cache container 20 according to the in 2 (c) is completely filled, so that the buffer volume 18 the complete space of the temporary storage tank 20 assumes takes place in the next clock according to 2 (d) the emptying of the intermediate storage volume from the intermediate storage container 20 to the steam generator 2 , This is superheated steam from the branch line 7 over a the first partial volume 22 of the temporary storage tank 20 supplied high pressure steam inlet 32 with associated high pressure steam inlet valve 33 , Introduced by the overpressure in the partial volume 22 due to the high pressure steam introduced, the piston becomes 21 in 2 (d) moved to the right, reducing the second sub-volume 23 that in the second subvolume 23 cached buffer volume 18 condensate over a the second partial volume 23 associated condensate outlet 34 and an associated condensate outlet valve 35 to the steam generator 2 to empty.

After completing the in 2 (d) illustrated work cycle is the caching volume 18 completely out of the buffer tank 20 deflated and the first partial volume 22 takes the full volume of the cache bin 20 and is filled with high pressure steam, as in 2 (e) shown. In this state, the next cycle of relaxation follows. This will be the first partial volume 22 via a residual steam outlet 36 the secondary steam cycle 13 supplied and via this the capacitor 5 via the secondary inputs 14 supplied, first by opening the turbocharger valves 1392 and 1393 over the turbocharger 15 , then by opening the bypass valve 1391 directly.

After completing the in 2 (e) illustrated relaxation clock is the temporary storage tank 20 ready to resume a cache volume 16 Condensate. This is done via a volume compensation opening 37 with associated volume compensation valve 38, a pressure or volume compensation via the volume compensation line 12.1 to the condenser 5 manufactured and also via a condensate inlet 39 with assigned condensate inlet valve 40 with the condensate outlet 12 of the capacitor 5 connected. After completely filling the temporary storage tank 20 and after finishing the in 2 (f) the cycle is shown emptying the buffer memory volume 18 as in 2 (a) shown and the cycle is closed.

By referring to the 2 (a) to 2 (f) illustrated embodiment of a temporary storage container 20 for use as a component of a recirculation arrangement according to the invention 6 Advantageously, a direct contact between the high-pressure steam and the cached condensate is avoided in order to avoid energy losses through heat transfer. In the embodiment of the temporary storage container 20 For example, some of the described inlets and outlets may under certain circumstances be designed identically to reduce complexity.

Incidentally, as mentioned, both the first buffer tank 9 as well as the second buffer tank 10 as well as the third cache container 11 through a buffer tank 20 be replaced according to the second embodiment or it may be in 1 shown embodiments of temporary storage containers with the temporary storage container 20 be combined according to the second embodiment.

With reference to the 3 (a) to 3 (d) is a further advantageous embodiment of the embodiment of a buffer storage arrangement 41 described which instead of one or more of the temporary storage container 9 . 10 . 11 according to 1 the return arrangement according to the invention 6 can be used.

The in the 3 (a) to 3 (d) illustrated temporary storage container assembly 41 has a condensing cylinder 42 and a steam cylinder 43 on. Both the condensing cylinder 42 as well as the steam cylinder 43 have a piston 44 . 45 on. Both pistons 44, 45 are in the condensing cylinder 42 or in the steam cylinder 43 freely displaceable in the axial direction. The piston 44 in the condensate cylinder 42 is over a rigid connection, such as a pole 46 , with the piston 45 in the steam cylinder 43 mechanically connected, allowing movements of the piston 44 in the condensate cylinder 42 positively coupled with corresponding movements of the piston 45 in the steam cylinder 43 and vice versa.

As with the description of the 2 (a) to 2 (f) were for the sake of clarity of representation in the 3 Inlet and outlet openings of the condensing cylinder 42 as well as the steam cylinder 43 each shown only if they are in the open state according to the power stroke shown in the sub-figure. Consequently, the condensing cylinder 42 and the steam cylinder 43 cumulatively all in the 3 (a) to 3 (d) to recognizing inlets or outlets and associated valves.

As in 3 (a) to recognize the piston divides 44 the condensing cylinder 42 the condensing cylinder 42 in a left partial volume 47 and a right subvolume 48 , On the other side, the piston divides 45 of the steam cylinder 43 the steam cylinder 43 also in a left partial volume 49 and a right subvolume 50 ,

In the in 3 (a) illustrated bar is the right partial volume 50 of the steam cylinder 43 via a high pressure steam inlet 51 which is in the right partial volume 50 of the steam cylinder 43 is guided, via an associated high-pressure steam inlet valve 52 with the branch line 7 connected. On the other hand, the left subvolume 49 of the steam cylinder 43 via the volume compensation opening 53 and the volume balance valve 54 via the volume equalization line 12.1 with the capacitor 5 connected for volume compensation.

The condensing cylinder 42 is in the in 3 (a) shown state with the right part volume 48 via the condensate inlet 55 and the condensate inlet valve 56 with the condensate outlet 12 of the capacitor 5 connected so that the right subvolume 48 can be filled with condensate. On the other hand, the left subvolume 47 of the condensing cylinder 42 over the condensate outlet 57 and the associated condensate outlet valve 58 with the steam generator 2 connected.

In the in 3 (a) shown state is due to the pressure in the right subvolume 50 of the steam cylinder 43 The piston 45 moved to the left. Due to the coupling through the lifting / push rod 46 leads the movement of the piston 45 of the steam cylinder 43 equally to movements of the piston 44 in the condensate cylinder 42 to the left. The lifting / pushing rod 46 has within each sub-container a different diameter, that is, the diameter of the lifting / pushing rod 46 in the steam cylinder 43 is smaller than that of the lifting / pushing rod 46 in the condensate cylinder 42 ,

By the movement of the piston 44 in the condensate cylinder 42 two things are done. On the one hand, the filling of the right sub-volume 48 of the condensate cylinder 42 via the condensate inlet 55 and the condensate inlet valve 56 with condensate from condensate outlet 12 of the capacitor 5 in the right Partial volume 48 allows. On the other hand, from the left subvolume 47 of the condensate cylinder 42 over the condensate outlet 57 the buffer volume 18 from the left partial volume 47 of the condensing cylinder 42 via the condensate outlet valve 58 to the steam generator 2 promoted.

In the in 3 (b) This is shown in the sub-volume 50 after completion of the lifting work with the high pressure from the branch line 7 minus vapor and vapor losses through the secondary steam cycle 13 in two stages, first over the turbocharger 15 and then directly into the condenser 5 recycled, taking advantage of the residual energy in the vapor volume. In this intermediate cycle, the piston coupled via the lifting / push rod move 44 . 45 Not.

After completing the in 3 (b) intermediate clocks illustrated is the vapor volume in the right sub-volume 50 of the steam cylinder 43 at the same pressure as the condenser 5 , Starting from this state, the in 3 (c) illustrated clock processed. At this clock is in the left subvolume 49 of the steam cylinder 43 over the left partial volume 49 associated high-pressure steam inlet 59 and the associated high pressure steam inlet valve 60 superheated steam from the branch line 7 in the left partial volume 49 of the steam cylinder 43 directed. Under the influence of the pressure in the partial volume 49, the piston 45 in the steam cylinder 43 moved to the right. This is the right subvolume 50 of the steam cylinder 43 over the right subvolume 50 assigned volume compensation opening 61 and the associated volume balance valve 62 via the volume equalization line 12.1 with the capacitor 5 connected for volume compensation.

By the movement of the piston 45 inside the steam cylinder 43 to the right is under mediation of the lifting / pushing rod 46 the piston 44 in the condensing cylinder 42 also moved to the right. It is about a left subvolume 47 of the condensing cylinder 42 associated condensate inlet 63 and an associated condensate inlet valve 64 the entry of condensate water from the condensate outlet 12 of the capacitor 5 in the left partial volume 47 of the condensing cylinder 42 allows. At the same time, in the right subvolume 48 of the condensing cylinder 42 of the cache volume 18 in the right subvolume 48 of the condensing cylinder 42 over a right partial volume 48 associated condensate outlet 65 and the associated condensate outlet valve 66 the steam generator 2 fed.

After completing the in 3 (c) illustrated clock lies in the 3 (d) shown state in which the piston 44 of the condensing cylinder 42 is on the right stop, so that the left part volume 47 of the condensing cylinder 42 essentially the entire volume of the condensate cylinder 47 occupies. The left partial volume 47 is thus with the buffer volume 16 Condensate filled. On the other hand, in the in 3 (d) shown state of the piston 45 of the steam cylinder 43 also on the right stop, so that the left partial volume 49 essentially the entire volume of the steam cylinder 43 occupies and with superheated steam from the branch line 7 is filled. The in 3 (d) shown state is analogous to that in 3 (b) shown state, however, the pistons 44 or 45 at the right stop, as in 3 (b) , are at the left stop. In the in 3 (d) shown intermediate clock is now the part volume 49 after completion of the lifting work with the high pressure from the branch line 7 minus vapor and vapor losses through the secondary steam cycle 13 in two stages, first over the turbocharger 15 and then directly into the condenser 5 recycled, taking advantage of the residual energy in the vapor volume. In this intermediate cycle, the piston coupled via the lifting / push rod move 44 . 45 Not.

With the in the 3 (a) to 3 (d) illustrated embodiment variant of a buffer storage arrangement 41 as part of a recycling arrangement according to the invention 6 also an optimized condensate return in steam power plants is possible, in which a direct contact of the used for expelling superheated steam from the branch line 7 with the buffer storage volume to be expelled 18 is avoided.

By parallel arrangement of a plurality of buffer storage arrangements 41 and with staggered duty cycles can also be a quasi-continuous condensate return flow to the steam generator 2 generate, in particular during the in 3 (b) and 3 (d) shown intermediate cycles a return of condensate is ensured.

LIST OF REFERENCE NUMBERS

1

Steam power plant

2

steam generator

3

heat

4

turbine

5

capacitor

6

Return arrangement

7

branch line

8th

High-pressure line

9

first temporary storage tank

91

High pressure steam inlet

92

High pressure inlet valve

93

condensate inlet

94

Condensate inlet valve

95

condensate

96

Kondensatauslassventil

97

Restdampfauslass

98

Volume compensation opening

99

Volume control valve

10

second buffer tank

101

High pressure steam inlet

102

High pressure steam inlet valve

103

condensate inlet

104

Condensate inlet valve

105

condensate

106

Kondensatauslassventil

107

Restdampfauslass

108

Volume compensation opening

109

Volume control valve

11

third intermediate storage tank

111

High pressure steam inlet

112

High pressure steam inlet valve

113

condensate inlet

114

Condensate inlet valve

115

condensate

116

Kondensatauslassventil

117

Restdampfauslass

118

Volume compensation opening

119

Volume control valve

12

condensate

12.1

Volume compensation line

13

Secondary steam circuit

1391

bypass valve

1392

first turbocharger valve

1393

second turbocharger valve

1394

pressure reducer

13101

bypass valve

13102

first turbocharger valve

13103

second turbocharger valve

13104

pressure reducer

13111

bypass valve

13112

first turbocharger valve

13113

second turbocharger valve

13114

pressure reducer

14

secondary input

15

turbocharger

16

Catch volume of condensate

17

High pressure steam volume

18

Interim storage volume

19

compensating volume

20

Intermediate storage container, second embodiment

21

piston

22

first partial volume

23

second partial volume

24

High pressure steam inlet

25A

High pressure steam inlet valve

26

condensate

26A

Kondensatauslassventil

27

Restdampfauslass

28

first condensate inlet

29

first condensate inlet valve

30

Volume compensation opening

31

Volume control valve

32

High pressure steam inlet

33

High pressure steam inlet valve

34

condensate

35

Kondensatauslassventil

36

Restdampfauslass

37

Volume compensation opening

38

Volume control valve

39

condensate inlet

40

Condensate inlet valve

41

Interim storage canister assembly

42

condensate cylinder

43

steam cylinder

44

piston

45

piston

46

Lift / push rod

47

left partial volume

48

right partial volume

49

left partial volume

50

right partial volume

51

High pressure steam inlet

52

High pressure steam inlet valve

53

Volume compensation opening

54

Volume control valve

55

condensate inlet

56

Condensate inlet valve

57

condensate

58

Kondensatauslassventil

59

High pressure steam inlet

60

High pressure steam inlet valve

61

Volume compensation opening

62

Volume control valve

63

condensate inlet

64

Condensate inlet valve

65

condensate

66

Kondensatauslassventil

Table 1: CLOCK ↓ CONTAINER → first buffer tank 9 second buffer tank 10 third buffer tank 11 I fill empty Relax Valve 92 94 96 97 99 102 104 106 107 109 112 114 116 117 119 switching status TO ON TO TO ON ON TO ON TO TO TO TO TO ON TO II empty Relax fill Valve 92 94 96 97 99 102 104 106 107 109 112 114 116 117 119 switching status ON TO ON TO TO TO TO TO ON TO TO ON TO TO ON III Relax fill empty Valve 92 94 96 97 99 102 104 106 107 109 112 114 116 117 119 switching status TO TO TO ON TO TO ON TO TO ON ON TO ON TO TO Table 2: CLOCK ↓ Connections first buffer tank 9 to secondary steam circuit thirteenth Connections of second intermediate storage tank 10 to secondary steam circuit 13 Connections third buffer tank 11 to secondary steam circuit thirteenth I fill empty Relax Valve 1391 1392 1393 13101 13102 13103 13111 13112 13113 switching status TO TO TO TO TO TO TO ON ON Ia 13111 13112 13113 ON TO TO II empty Relax fill Valve 1391 1392 1393 13101 13102 13103 13111 13112 13113 switching status TO TO TO TO ON ON TO TO TO IIa 13101 13102 13103 ON TO TO III Relax fill empty Valve 1391 1392 1393 13101 13102 13103 13111 13112 13113 switching status TO ON ON TO TO TO TO TO TO IIIa 1391 1392 1393 ON TO TO

Claims (14)

Return arrangement (6) for returning at the output of a downstream of a turbine, (4) connected capacitor (5) condensate back to the input of a steam generator (2) in a steam power plant, characterized by a branch line (7) for branching a branch flow between the steam generator (2) and the turbine (4), at least one intermediate storage tank arrangement (9, 10, 11, 20, 41) for receiving a buffer storage volume (18) of condensate with at least one condensate outlet opening (95, 105, 115, 26, 34, 57, 65 ) for discharging condensate, and means (92, 102, 112, 25A, 33, 52, 60) for establishing an operative connection between the branch line (7) and the temporary storage container arrangement (9, 10, 11, 20, 41) to communicate over the Condensate outlet opening (95, 105, 115, 26, 34, 57, 65) Conveying condensate out of the intermediate storage container arrangement (9, 10, 11, 20, 41), wherein the intermediate storage container arrangement (9, 10, 11, 20, 41) 41) via the Kondensatauslassöffnung (95, 105, 115, 26, 34, 57, 65) with the steam generator (2) is arranged connectable. Return arrangement (6) after Claim 1 , characterized in that a plurality, preferably two, in particular three, intermediate storage container arrangements (9, 10, 11, 20, 41) are provided. Return arrangement (6) after Claim 1 or 2 , characterized in that the at least one intermediate storage container arrangement (9, 10, 11, 20, 41) has two materially separate partial volumes (22, 23, 47, 48, 49, 50) which are in pressure communication with one another. The return arrangement (6) according to one of the preceding claims, characterized in that the intermediate storage container arrangement (9, 10, 11, 20, 41) has a piston-like separating element (21, 44, 45) for separating the partial volumes (22, 23, 47, 48 , 49, 50). Return arrangement (6) according to one of the preceding claims, characterized in that the intermediate storage container arrangement (9, 10, 11, 20, 41) has two partial containers (42, 43) each provided with a piston-like separating element (21, 44, 45), wherein the separating elements (21, 44, 45) of each partial container (42, 43) are mechanically coupled to one another. Return arrangement (6) after Claim 5 , characterized in that a pressure application surface of the separating element (44, 45) between the two sub-containers (42, 43) is designed differently. Return arrangement (6) after Claim 5 or 6 , characterized in that the separating elements (44, 45) by means of at least one lifting and / or push rod (46) are coupled. Return arrangement (6) according to one of the preceding claims, characterized in that a secondary steam circuit (13) is provided for recirculation via the branch line (7) branched medium into the condenser (5), wherein the secondary steam circuit (13) the branch line (7 ), at least one of the intermediate storage container assemblies (9, 10, 11, 20, 41), and a return conduit connecting the intermediate storage container assemblies (9, 10, 11, 20, 41) to an inlet of the condenser (5). Return arrangement (6) after Claim 8 characterized in that the secondary steam circuit (13) comprises means (15) for converting the energy and / or pressure reducing means contained in the secondary steam circuit (13) to reduce the pressure of the media flowing in the secondary steam circuit (13) , Method for recirculating condensate arising at the outlet (12) of a condenser (5) connected downstream of a turbine (4) back to the inlet of a steam generator (2) in a steam power plant, characterized in that - between the steam generator (2) and the turbine ( 4) branching off a branching stream, - a buffer storage volume (16, 18) of condensate is buffered, - an operative connection between the branching stream and the buffering volume (18) is established to reduce the buffering volume (18) of condensate by means of the energy of the branching stream to the steam generator (2 ) to empty. Method according to Claim 10 , characterized in that after emptying the intermediate storage volume (18) condensate to the steam generator (2) a residual energy of the branch current is used for converting into mechanical and / or electrical energy. Method according to Claim 10 or 11 characterized in that two intermediate storage volumes (16, 18) of condensate are buffered sequentially, wherein to achieve a quasi-continuous condensate return one of the intermediate storage volume (16) is filled, while at the same time the other intermediate storage volume (18) to the steam generator (2) is emptied , Method according to one of Claims 10 to 12 , characterized in that a third intermediate storage volume (19) is used, which is brought to the pressure at the outlet of the condenser (5) during the filling or emptying of the first or second intermediate storage volumes. Method according to one of Claims 10 to 13 , characterized in that it is provided with a return arrangement (6) according to one of Claims 1 to 9 is carried out.

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