EP2199724A1 - Method for operating a regenerative heat exchanger and regenerative heat exchanger with improved efficiency - Google Patents

Abstract

The method involves passing a fresh air volume stream (10) to be heated and a flue gas volume stream (11) to be cooled through a rotor. An inflow and outflow fresh air volume streams (10a, 10b) is absorbed at a front side (5a, 5b) of the rotor, respectively. The heated and the cooled fresh air and flue gas volume stream at the rotor are sealed by a rotor seal, and a leakage volume stream occurred at the rotor is guided to the heated air volume stream. The leakage volume stream is interrupted at the front sides of the rotor and guided to the inflow and outflow gas volume streams. An independent claim is also included for a regenerative heat exchanger comprising a rotor.

Description

The invention relates to a method for operating a regenerative heat exchanger, in particular for air preheating in power plants, according to the features of the preamble of claim 1. The invention further relates to a regenerative heat exchanger according to the features of the preamble of the independent claim.

Regenerative heat exchangers of the type in question (hereinafter also referred to as heat exchangers) serve to transfer heat from at least one gas volume flow to at least one other gas volume flow. For this purpose, the heat exchanger may comprise a rotating (or rotating or also circulating) storage mass (referred to below as a rotor) which moves relative to fixed flow connections and in this case is warmed up alternately by the at least one gas volume flow and is cooled again by the at least one other gas volume flow whereby thermal energy of at least one is transferable to at least one other gas volume flow.

The rotor of a regenerative heat exchanger is usually formed as a substantially circular cylindrical drum, with slight deviations from this form are possible. The rotor has a central axis of rotation. The gas flow rates flow through the rotor substantially parallel to the axis of rotation. The flow is usually in opposite directions (so-called countercurrent process). In order to provide sufficient heat storage mass available, but also to increase the mechanical stability of the rotor, this has a sectoring or segmentation in several cells or chambers, which also serve as flow channels for the gas flow rates. In these chambers usually heat-storing materials are arranged, such as. So-called Heizblechpakete.

In operation, the individual chambers of the rotor are flowed through by a hot or hot gas flow, which may be, for example, a flue gas from a combustion process. As a result of the flow with the warm or hot gas flow, the heat-storing masses of the flow-through chambers heat up. In this case, heat is withdrawn from the gas flow volume flowing through, so that it has a lower temperature at the exit from the rotor than at entry. As a result of the rotor rotation, the heated chambers finally reach the section where a cooler or cold gas flow, for example. Fresh air, flows through the rotor and is heated to the heat-storing masses of these chambers, the heat-storing materials are cooled again. In this type of heat transfer, so to speak, a heat storage capacity of the rotor is used to heat a first gas volume flow and to cool a second gas volume flow.

Alternatively, a rotor may, for example, also be designed to be stationary and the flow connections can move relative thereto.

When using fresh air as the gas volume flow to be heated, the heat exchanger can be used for so-called air preheating. By air preheating the efficiency of a power plant can be increased and pollutant emissions can be reduced.

To reduce mass losses or volume losses with respect to the gas flow rates, a complex sealing is required on the rotor, which has long been the subject of numerous further developments. The sealing system for a rotor usually comprises at least one peripheral seal and at least one radial seal. A circumferential seal seals the gas flow rates flowing through the rotor on the outer circumference of the rotor to the outside. A circumferential seal may comprise an axial seal on the outer circumference of the rotor. A radial seal should prevent a so-called flow short circuit or short-circuit volume flow between the individual gas volume flows on a rotor end face. Due to the relative movement of the rotor to the seals and due to varying thermal expansion, gaps between the seals and the rotor are inevitable, through which leakage volume flows occur, especially between the gas flow rates (so-called flow shorts), typically from the higher pressure gas flow to the gas flow at the lower pressure. In addition to volume losses, this also leads to energy losses and thus to an unsatisfactory efficiency.

To improve the efficiency of regenerative heat exchangers are known from the prior art, among other suction and extraction systems.

In the US 2,665,120 It is described to encapsulate the rotor of a regenerative heat exchanger and to suck the leakage volume flows by means of a draft fan (fan) and to supply or to return the gas volume flow to be heated up. The return occurs either before (upstream) or after (downstream) the rotor. If the return takes place downstream of the rotor, ie in the already heated by the rotor gas flow, a previous heating of the extracted leakage volume flows is provided by means of a complex heat exchanger design to prevent cooling of the gas flow rate to the rotor.

In the DE 34 37 945 A1 is the extraction of the leakage volume flows on the "hot side" (more below) of the rotor and their return to be heated in the gas flow before the rotor described.

The EP 0 588 185 A1 describes a rotor housing which consists of an upper and a lower part chamber, from which together or separately leakage volume flows can be sucked by means of a fan. A return of the extracted leakage volume flows in one of the gas flow rates is not described here.

The known from the prior art extraction and extraction systems do not lead in practice to improvements in the efficiency of the transfer of heat energy. In part, even a deterioration in the efficiency has been observed.

The object of the invention is to improve the efficiency of a regenerative heat exchanger.

This object is achieved by a method having the features of claim 1 and by a regenerative heat exchanger having the features of the independent claim. Advantageous developments are characterized by the features of the respective dependent claims.

In the method according to the invention for operating a regenerative heat exchanger, the rotor, which is preferably rotatably mounted, is flowed through by at least a first gas volume flow to be heated, in particular fresh air, whereby the gas volume flow heats up as the rotor flows through the heat-storing masses. This is used in particular for air preheating of fresh air for a power plant. Furthermore, the rotor is flowed through by at least a second, to be cooled gas volume flow, such as in particular a flue gas or combustion gas or exhaust gas, which emits its heat to the heat-storing masses of the rotor and thereby cooled itself.

The rotor has a first end face or face on which the inflowing first gas volume flow to be heated enters the rotor. Opposite the first end face, the rotor has a second end face or end face on which the outflowing first gas volume flow to be heated emerges from the rotor again. Usually, the first end face is also referred to as "cold side" and the second end side as "hot side".

The first gas volume flow and the second gas volume flow are sealed at the rotor by means of at least one rotor seal in order to limit volume losses and in particular flow short circuits. A rotor seal is, in particular, a circumferential seal which seals a gas volume flow on the outer circumference of the rotor, and / or a radial seal which seals the gas volume flows relative to one another and should prevent flow short circuits or short-circuit volume flows.

Since leakage volume flows occur in the region of a rotor seal, it is provided according to the invention that at least one leakage volume flow is detected or collected at the first end side or in the region of this end side of the rotor and supplied to the inflowing first gas volume flow and / or at least one leakage volume flow at the second end End face, or detected in the region of this end face of the rotor or collected and supplied to the outflowing first gas volume flow.

A leakage volume flow is in particular a short-circuit volume flow from the first gas volume flow into the second gas volume flow, which occurs in the region of a radial seal on the first end side of the rotor or on the second end side of the rotor. In this case, it is thus in fact a return of a trapped leakage volume flow in the first, to be reheated gas flow.

The fact that capturing or collecting a leakage volume flow that occurs in the region of a rotor seal can usually not be complete for technical reasons, so that capturing or collecting a leakage volume flow in the context of this invention refers to a substantial part of the leakage volume flow, which under the respective technical conditions detectable or is trappable. Detecting and collecting are to be interpreted widely in the context of this invention and include all measures that are suitable to get hold of a leakage volume flow.

The inventive method differs from the above-mentioned prior art initially in that a leakage volume flow is collected only in the region of one of the end sides or both end faces of the rotor. This can be distinguished, which temperature level has a leakage volume flow respectively. Furthermore, the method according to the invention differs from the prior art in that, depending on the temperature level of the leakage volume flow, a corresponding supply or return into the inflowing and still cool first gas volume flow or the outflowing and already warmed first gas volume flow takes place (so to speak fluidically always on the same Side of the rotor). This energy advantages are achieved, which increase the efficiency over the prior art, which will be explained in more detail below.

In a regenerative heat exchanger used in a power plant, for example, for heat transfer from a hot flue gas volume flow (from a combustion process) to a fresh air volume flow, a leakage volume flow (short-circuit volume flow) from the fresh air flow into the flue gas volume flow is usually given in the region of a radial seal. When determining the operating parameters and the configuration of the regenerative heat exchanger, such leakage volume flows are taken into account, since the leakage volume flow from the fresh air volume flow into the flue gas volume flow leads to additional cooling of the flue gas volume flow by about 3 to 7 K (so-called "corrected" flue gas or exhaust gas temperature). There is thus the danger that the acid dew point temperature of a constituent of the flue gas to be cooled is undershot and damage (in particular corrosion) of subsequent system components (for example dedusting plants and filter systems) in the flue gas line occurs. It must therefore be ensured that the temperature of the flue gas volume flow at the outlet of the rotor or the outlet from the regenerative heat exchanger, despite the additional cooling by the leakage volume flow from the fresh air volume flow, is higher than a critical acid dew point. The additional cooling of the flue gas volume flow through the leakage volume flow from the fresh air volume flow must therefore be taken into account in the design of the regenerative heat exchanger and its operating parameters. On the other hand, this additional cooling of the flue gas volume flow for the heat transfer from the flue gas volume flow to the fresh air volume flow is not energetically available. Desirable is therefore a lower "uncorrected" flue gas temperature.

By the separate detection of a warm or hot leakage volume flow and its supply or return to the outflowing and already warmed fresh air flow, and / or a cool or cold leakage volume flow and its supply, or return to the inflowing and (still) cool fresh air flow the negative additional cooling effect can be largely avoided. In other words, the now essentially "uncorrected" flue gas temperature can be lowered to a similar level to the previously "corrected" flue gas temperature. With unchanged inlet temperature of the gas flow rates into the rotor and unchanged gas flow rates can be increased as a result, the heat transfer from the flue gas volume flow to the fresh air volume flow without a critical acid dew point is exceeded in the flue gas volume flow. The increase in the heat transfer is, for example, possible by constructive design of the heat-storing masses.

As a result of the defined feedback at the same time an unwanted cooling of the flue gas volume flow in front of the rotor and also an unwanted cooling of the flue gas volume flow to the rotor is largely avoided, which additionally increases the efficiency of the regenerative heat exchanger.

As a result, the downstream temperature (ie, the temperature after the rotor or after the regenerative heat exchanger) of the fresh air volume flow and thus the amount of heat in the combustion air for the power plant combustion process increases. This additional amount of heat reduces the fuel requirement. Based on a boiler output of 700 to 800 MW, savings in operating costs of 150,000 to 400,000 euros per year can be calculated without reducing output, with savings likely to increase over the next few years due to rising fuel prices. As a further and significant advantage, there is also a reduction in the emission of noxious gases, in particular CO ₂ .

According to the invention, it is preferably provided that at least one leakage volume flow is collected at the first end side of the rotor and fed to the inflowing first gas volume flow, where it is actually introduced or fed into it, and that at least one leakage volume flow is collected at the second end side of the rotor and is supplied from flowing first gas volume flow, and there is actually introduced or fed into this. Through this two-sided detection (relative to the end faces of the rotor) and separate supply or return of leakage volume flows, the efficiency of the regenerative heat exchanger improved to a considerable extent. Nevertheless, it goes without saying a detection and supply or return to only one end side of the rotor possible and advantageous.

According to an advantageous development of the method, it is provided that the supply or return of the leakage volume flow collected by the first end face of the rotor into the first gas volume flow does not take place directly, but rather upstream of the rotor. By "upstream" is meant that the supply is in the flow direction in front of the rotor. Alternatively or additionally, it is provided that the return of the collected from the second end face of the rotor leakage volume flow in the first gas volume flow is not directly, but downstream of the rotor. By "downstream" is meant that the supply is in the direction of flow after the rotor. Thus, the detection or collection of a leakage volume flow and its supply or return to the first gas flow is structurally and structurally separated.

In this case, provision is made in particular for the supply or return of a collected leakage volume flow to take place in the first gas volume flow in each case in spatial proximity, preferably in the immediate vicinity of the rotor. Thus, the flow paths can be kept structurally short. A supplied or recycled leakage volume flow is subject to only a slight temperature influence.

Advantageously, it is provided that at least one of the first end face of the rotor and at least one detected on the second end face of the rotor leakage flow is recycled on separate paths each upstream in the inflowing first gas volume flow and downstream in the outflowing first gas volume flow. A path or return path is any device which is suitable for transporting or passing through a gas volume flow. A path or return path is in particular a line system of pipes and pipe sections or the like.

It is preferably provided here that at least one blower device is used per path. By means of the blower device, a negative pressure can be generated with which a leakage volume flow can be detected or collected at one end face of the rotor by suction. At the same time, an excess pressure can be generated with the blower device, with which the extracted leakage volume flow can be fed or returned along the path or return path to the first gas volume flow, where it can be introduced or fed into it. A Blower device is in particular a fan which is preferably arranged in a line system.

It is further preferred that at least one leakage volume flow is detected or collected at the first end side and / or the second end side of the rotor in the region of a radial seal, preferably by means of suction. This measure thus relates to a particularly disadvantageous short-circuit volume flow, in particular from the first gas volume flow into the second gas volume flow.

Likewise, it is additionally or alternatively preferred for at least one leakage volume flow to be detected or collected at the first end side and / or the second end side of the rotor in the area of a peripheral seal, preferably by suction. This also leads to an improvement in the efficiency.

According to a particularly preferred development of the method according to the invention, it is provided that at least one first gas volume flow to be heated and at least one second gas volume flow to be cooled are directed in opposite directions, i. in countercurrent process, flow through the rotor. In this case, both gas volume flows at the first end side ("cold side") have a lower temperature level than at the second end side ("hot side"). It is thus easy to distinguish which temperature level has a detected or trapped leakage volume flow. A detected at the hot end side of the rotor leakage flow is supplied to the outflowing first gas volume flow or recycled into this and a detected on the cold end side of the rotor leakage flow is supplied to the inflowing first gas flow volume or recycled into this. Alternatively, the rotor, at least of at least second gas flow rates, also be flowed through in the same direction.

In a preferred development of the method, at least two first gas volume flows are provided, wherein the feeding of at least one collected leakage volume flow, preferably of all collected leakage volume flows, into only one of these two first gas volume flows. This will be discussed in more detail in connection with the figures. Alternatively, a separate return to two or more first gas flow rates is possible.

The regenerative heat exchanger according to the invention comprises a rotor through which flows at least two gas volume flows, the rotor having a first end face on which an inflowing first gas volume flow to be heated enters the rotor and wherein the rotor Furthermore, one of the first end face opposite second end face has at which the outflowing first, to be reheated gas flow again exits the rotor. Furthermore, at least one rotor seal, in particular a radial seal and / or a peripheral seal, on the rotor, for sealing the first and the second gas volume flow. The regenerative heat exchanger according to the invention also comprises a detection device or collecting device for a leakage volume flow which occurs in the region of a rotor seal, and at least one feed or feed device or return device for the detected or trapped leakage volume flow into the first gas volume flow.

According to the invention, at least one collecting device is provided on the first end side of the rotor with at least one associated supply or supply device for the leakage volume flow collected at the first end side into the oncoming first gas volume flow, and / or at least one collecting device on the second end side with at least one associated supply or supply Feed device for the collected at the second end face leakage volume flow in the outflowing first gas volume flow.

The regenerative heat exchanger according to the invention is preferably suitable for use of the method according to the invention described above. The method features described above and their advantages are therefore correspondingly transferable to the regenerative heat exchanger according to the invention.

A collecting device is any device that is suitable for detecting or collecting a leakage volume flow. A catcher may be a system of individual components. A collecting device is preferably a suction device.

A feed or feed device serves to supply or return a leakage volume flow detected or collected by a collecting device into the first gas volume flow. A feed or a feed device is preferably realized by a line system, by means of which the leakage volume flow detected or collected at a rotor seal is fed to the first gas volume flow in a defined manner. If the leakage volume flow starts from the first gas volume flow, the supply or feed device is actually a return or return device.

The line system of at least one feed or feed device preferably comprises at least one blower device with which a defined flow can be generated in this line system.

The blower device is designed such that in a connecting line which is arranged between this blower device and a rotor seal, a negative pressure can be generated, with which the leakage volume flow can be sucked at the relevant rotor seal. In particular, the rotor seal is at least one radial seal and / or at least one circumferential seal which is fluidically connected to the blower device via the connecting line. At least one radial seal and / or at least one peripheral seal is preferably designed to be split and / or has a plurality of openings, so that a leakage volume flow occurring at this rotor seal can be extracted in a simplified manner by means of negative pressure.

The same blower device furthermore generates in a connecting line, which is arranged between this blower device and the first gas volume flow, an overpressure, with which the sucked at the rotor seal leakage volume flow can be fed to the first gas volume flow or fed back into these, actually introduced into this or fed ,

It is particularly preferably provided that at least one suction or suction device is provided for a leakage volume flow at the first end face of the rotor, in particular in the region of a radial seal and / or a circumferential seal, with an associated supply or feed device for the sucked leakage volume flow in the inflowing first gas volume flow. It is also provided that at least one suction device for a leakage volume flow is provided on the second end face of the rotor, in particular in the region of a radial seal and / or a circumferential seal, with an associated supply or feed device for the extracted leakage volume flow into the outflowing first gas volume flow. The feeders or feeders are formed separately from each other and each comprise at least one blower device. This corresponds to a preferred and particularly advantageous embodiment of the invention.

The invention can be realized in a manner analogous to a heat exchanger with stationary heat-storing masses.

Fig. 1

ein bevorzugtes Ausführungsbeispiel der Erfindung in einer schematischen Darstellung, und

Fig. 2

ein alternatives Ausführungsbeispiel der Erfindung in einer schematischen Darstellung.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to FIGS. Show it:

Fig. 1

a preferred embodiment of the invention in a schematic representation, and

Fig. 2

an alternative embodiment of the invention in a schematic representation.

The FIG. 1 shows a generally designated 1 regenerative heat exchanger which is used in a power plant. This comprises a circular cylindrical rotor 2 which is aligned horizontally and rotatably supported about a vertical axis 3. Inside the rotor 2 are heat storage 4 (eg. Heizblechpakete as described above). The rotor has a first, lower end side 5a, a second, upper end side 5b and a jacket wall (peripheral wall) 7. At the end faces 5a and 5b are unspecified radial seals 8a and 8b and unspecified perimeter seals 9a and 9b.

As shown, the rotor 2 on the left side flows through a first gas volume flow 10 from bottom to top, this being a fresh air volume flow. The fresh air volume flow 10 is sucked in by a blower device 14 and fed to the rotor 2. The fresh air volume flow 10 enters at the lower end face 5a of the rotor 2 in this and at the upper end face 5b again and is heated during the passage of the rotor 2 to the heat accumulators 4, which in this case to the same extent cool (as described above). With reference to the rotor 2, the inflowing fresh air volume flow is denoted 10a and the outflowing fresh air volume flow is 10b.

On the right side, the rotor 2 is traversed by a second gas volume flow 11 from top to bottom, this being a flue gas volume flow from a combustion process. The flue gas volume flow 11 occurs at the upper end face 5b in the rotor 2 and at the lower end 5a again from the rotor 2 and is cooled during the passage of the rotor 2 to the cool heat accumulators 4, which in this case heat up to the same extent and then the heating of the fresh air volume flow 10 are available (as described above). After leaving the rotor 2, the already cooled flue gas volume flow is supplied to flue gas purification systems and / or filter devices 20.

As a result of the opposite flow, the temperatures of both gas flow rates 10 and 11 at the upper, second end face 5b of the rotor 2 are higher than at the lower, first Front side 5a. Therefore, the upper end face 5b may also be referred to as the "hot side" and the lower end face 5a may also be referred to as the "cold side".

In order to seal the two gas volume flows 10 and 11 on the rotor 2, the radial seals 8a and 8b, and the circumferential seals 9a and 9b are provided. The circumferential seals 9a and 9b are intended to seal off the gas volume flows 10 and 11 at the outer edge or outer circumference of the rotor 2, while the radial seals 8a and 8b are intended to prevent thorough mixing of the gas volume flows 10 and 11 by flow short circuits or short-circuit volume flows. As a result of changing thermal and mechanical stress, there are always gaps or residual gaps between the seals 8a, 8b, 9a and 9b and the rotor 2 through which leakage volume flows occur. In particular in the area of the radial seals 8a and 8b, leakage volume flows are also favored by pressure differences in the gas volume flows 10 and 11, wherein the fresh air volume flow 10 usually has a higher pressure than the flue gas volume flow 11 because of the blower device 14. This leads to fresh air leakage volume flows 12a and 12b, so that fresh air with a lower temperature level into the flue gas volume flow 11 passes over, resulting in an undesirable and adverse cooling effect in the flue gas volume flow 11 (as described in detail above).

It is therefore intended to trap the leakage volume flows 12a and 12b in the region of the radial seals 8a and 8b and to supply the leakage volume flows from the "hot" end face 5b of the rotor 2 to the outflowing fresh air volume flow 10b or into the latter and from the "cold" end face 5a of FIG Rotor 2 to be supplied to the oncoming gas flow 10a or to initiate in this. Due to this separate recycling of the leakage volume flows from the "hot" end face into the already warmed, outflowing fresh air volume flow 10b and from the "cold" side into the still cool, incoming fresh air volume flow 10a, the above-described undesired and disadvantageous cooling effect in the flue gas volume flow 11 can be avoided As a result, the efficiency of the heat exchanger and thus also of the power plant can be increased (as explained in detail above). Also, in the flue gas to be cooled, the condensation of critical flue gas constituents in cold temperature strands can be prevented or at least reduced.

The collection of the leakage volume flows or fresh air leakage volume flows 12a and 12b takes place by suction at the radial seals 8a and 8b. To facilitate suction, the radial seals 8a and 8b may be split and / or with a plurality of openings be formed (not shown) through which a negative pressure effectively applied in the gap or residual gap between the radial seal 8a and 8b and the rotor 2 and thereby the leakage volume flows can be collected. The negative pressure is generated in each case by a fan device 16a and 16b which, for example, can be a fan or the like. Between the blower devices 16a and 16b and the radial seals 8a and 8b, a connecting line 17a and 17b is respectively arranged, via which the collected or sucked leakage volume flows 12a and 12b are led away. Of the blower devices 16a and 16b, in each case one connecting line 18a or 18b extends into the inflowing fresh air volume flow 10a or into the outflowing fresh air volume flow 10b. These connecting lines 18a and 18b are used to feed or return the collected and removed leakage volume flows 12a and 12b in the fresh air volume flow 10. The blower devices 16a and 16b are designed such that in the connecting lines 17a and 17b, a negative pressure and in the connecting lines 18a and 18b generate an overpressure.

The connecting lines 17a and 18a form, here together with the blower device 16a, a line system for the supply or return of a at the first end face ("cold side") 5a of the rotor 2 caught or sucked leakage volume flow 12a in the incoming fresh air flow 10a. Independently of this, the connecting lines 17b and 18b, here together with the blower device 16b, form a second separate line system for the supply or return of a leakage volume flow 12b caught or drawn off on the second end face ("hot side") 5b of the rotor 2 into the outflowing section Fresh air volume flow 10b. The cable cross-sections and the fan power are dimensioned accordingly. It is also possible to segment the connecting lines or to arrange several connecting lines in parallel. It is also possible to provide several blower devices in parallel or in series.

As an alternative to the embodiment described above, it is also possible to provide an extraction and supply or return to only one of the end faces 5a and 5b of the rotor 2 (not shown), resulting in a lower structural complexity already a significant improvement in efficiency. As an alternative or in addition, the leakage volume flows at the peripheral seals 9a and 9b can also be collected and respectively supplied to the incoming fresh air volume flow 10a or the outflowing fresh air volume flow 10b and fed or introduced into it. This is in the FIG. 1 shown on the left side of the rotor 2 by way of example with a dashed line for the circumferential seal 9a. For the suction and feed or return (in this case in the incoming fresh air flow 10a) can Another blower device may be used or the blower device 16a may be used for the extraction of the leakage volume flow 12a on the lower end side 5a. In order to simplify the suction also at the peripheral seals 9a and 9b, the radial seals 8a and 8b may be divided and / or formed with a plurality of openings. By extracting a leakage volume flow to at least one of the peripheral seals 9a and 9b, the efficiency of the regenerative heat exchanger 1 can be further improved. According to the invention, the supply or recirculation of a leakage volume flow detected at a peripheral seal 9a on the lower end side ("cold side") 5a takes place into the still cool fresh air volume flow 10a and the supply or return of one to a peripheral seal 9b at the upper end side (FIG. hot side ") 5b detected leakage volume flow in the outflowing, heated fresh air flow 10b.

The FIG. 2 shows an alternative embodiment of the invention. Hereinafter, only the differences from the embodiment of the FIG. 1 (see above). Therefore, the above statements apply to the embodiment of FIG. 1 analogous.

The main difference to the embodiment of FIG. 1 is given in that the rotor 2 is flowed through on its left side by two separate gas flow streams 100 and 101 in the same direction, which are respectively heated during their flow through the rotor. The gas volume flow 100 may, for example, be a secondary air volume flow and the gas volume flow 101 may be, for example, a primary air volume flow. These gas flow rates 100 and 101 serve different uses in a power plant. Notwithstanding the representation in which the two gas volume flows 100 and 101 flow through the rotor 2 side by side, they can flow through the rotor at different locations, relative to the rotor cross-section. The separate supply or return of the collected and sucked at the radial seals 8a and 8b leakage volume flows takes place here, both sides of the rotor 2 according to the above, each in the same gas flow 100 (secondary air volume flow). Alternatively, it is also possible to supply the collected leakage volume flows to the other gas volume flow 101 (primary air volume flow).

In the embodiment of the FIG. 2 It is also conceivable to provide the suction of a leakage volume flow to only one end face 5a or 5b of the rotor 2. Likewise, the suction of a leakage volume flow can also take place on a circumferential seal 9a and / or 9b, as described above.

LIST OF REFERENCE NUMBERS

1

Regenerative heat exchanger

2

rotor

3

axis of rotation

4

heat storage

5a

first face (bottom)

5b

second face (top)

7

shell wall

8a

Radial seal (s) on the first end face

8b

Radial seal (s) on the second end face

9a

Peripheral seal (s) on the first end face

9b

Peripheral seal (s) on the second end face

10

Fresh air volume flow (first gas volume flow)

10a

incoming fresh air volume flow

10b

outflowing fresh air volume flow

11

Flue gas volume flow (second gas volume flow)

12a

Leakage volume flow at the first end

12b

Leakage volume flow at the second end face

14

Blower device for the fresh air volume flow

16a

Blower device on the first end face

16b

Blower device on the second end face

17a

Connecting line to the radial seal at the first end

17b

Connecting line to the radial seal at the second end face

18a

Connecting line in the fresh air volume flow

18b

Connecting line in the fresh air volume flow

20

Filtration devices

100

Gas volume flow (secondary air)

101

Gas volume flow (primary air)

140, 141

Blower device for gas flow rates 100 and 101

Claims (15)

Method for operating a regenerative heat exchanger (1) comprising a rotor (2) through which flows at least a first gas volume flow (10) to be heated and at least one second gas volume flow (11) to be cooled; wherein the inflowing first gas volume flow (10a) on a first end face (5a) of the rotor (2) enters the rotor (2) and on a second end face (5b) of the rotor (2) as outflowing first gas volume flow (10b) again out of the Rotor (2) emerges;
wherein the first (10) and / or the second (11) gas volume flow on the rotor (2) is / are sealed by means of at least one rotor seal, and
wherein at least one leakage volume flow occurring at a rotor seal is collected and supplied to the first gas volume flow (10),
characterized,
that the leakage volume flow at the first end face (5a) of the rotor (2) collected and the inflowing first gas flow (10a) is supplied and / or that the leakage volume flow on the second end side of the rotor (2) collected and the outflowing first gas flow (10b) is supplied. Method according to claim 1,
characterized,
in that at least one leakage volume flow trapped on the first end side (5a) of the rotor (2) is introduced upstream of the rotor (2) into the first gas volume flow (10a) and / or at least one on the second end side (5b) of the rotor (2 ) trapped leakage volume flow downstream of the rotor (2) in the outflowing first gas volume flow (10b) is initiated. Method according to claim 2,
characterized,
that the introduction of at least one captured leakage volume flow in the first gas flow (10) near the rotor (2), and preferably in the immediate vicinity of the rotor (2). Method according to one of the preceding claims,
characterized,
that in each case at least one leakage volume flow on the first end face (5a) of the rotor (2) and on the second end face (5b) of the rotor (2) is collected, which then on separate paths in each case the inflowing first gas volume flow (10a) and the outflowing first Gas volume flow (10b) are supplied. Method according to claim 4,
characterized,
in that at least one blower device (16a, 16b) is used per path to generate a flow. Method according to one of the preceding claims,
characterized,
in that at least one leakage volume flow (12a, 12b) is collected at the first end face (5a) and / or at the second end face (5b) of the rotor (2) in the region of a radial seal (8a, 8b), the catching being preferably by suction he follows. Method according to one of the preceding claims,
characterized,
in that at least one leakage volume flow is collected at the first end face (5a) and / or at the second end face (5b) of the rotor (2) in the region of a peripheral seal (9a, 9b), the catch preferably taking place by suction. Method according to one of the preceding claims,
characterized,
in that at least a first gas volume flow (10) and at least a second gas volume flow (11) flow through the rotor (2) in opposite directions. Method according to one of the preceding claims,
characterized,
that two first volume of gas streams are provided at least and the feeding of all the collected leakage volume flow in only one of these two first gas volume flow takes place. Regenerative heat exchanger (1) comprising: - One of at least two gas flow rates (10, 11) through-flowed rotor (2), wherein the rotor (2) has a first end face (5a) at which an inflowing first, to be reheated gas volume flow (10) enters the rotor (2), and wherein the rotor (2) has a second end face (5b) at which the outflowing first gas volume flow (10) again emerges from the rotor (2); and - At least one rotor seal, in particular radial seal (8a, 8b) and / or peripheral seal (9a, 9b), for sealing the first (10) and / or the second (11) gas flow on the rotor (2); and at least one collecting device for at least one leakage volume flow at a rotor seal and at least one feed device for the collected leakage volume flow into the first gas volume flow (10), characterized by
at least one collecting device on the first end face (5a) with at least one associated feed device for the leakage volume flow collected at the first end side (5a) into the oncoming first gas volume flow (10a) and / or at least one catch device on the second end side (5b) with at least one associated feeding device for the at the second end face (5b) trapped leakage volume flow in the outflowing first gas volume flow (10b). Regenerative heat exchanger (1) according to claim 10,
characterized,
in that a supply is formed from a line system (17a, 18a; 17b, 18b) through which the collected leakage volume flow defined is fed to the first gas volume flow. Regenerative heat exchanger (1) according to claim 11,
characterized,
in that at least one blower device (16a, 16b) is arranged in the line system (17a, 18a; 17b, 18b). A regenerative heat exchanger (1) according to claim 12,
characterized,
in that at least one connecting line (17a, 17b) is encompassed by a blower device (16a, 16b) with respect to at least one rotor seal, in particular to a radial seal (8a, 8b) and / or a circumferential seal (9a, 9b). Regenerative heat exchanger (1) according to one of claims 10 to 13,
characterized,
in that at least one radial seal (8a, 8b) and / or at least one peripheral seal (9a, 9b) is designed to be divided and / or provided with a plurality of openings. A regenerative heat exchanger (1) according to any one of claims 10 to 14,
characterized,
in that at least one suction device for a leakage volume flow (12a) is provided on the first end face (5a) of the rotor (2), in particular in the region of a radial seal (8a) and / or a circumferential seal (9a), with an associated feed device for the suctioned-off Leakage volume flow in the inflowing first gas volume flow (10a), and that on the second end face (5b) of the rotor (2), in particular in the region of a radial seal (8b) and / or a peripheral seal (9b), at least one suction device for a leakage volume flow (12b ) is provided, with an associated feed device for the sucked leakage volume flow in the outflowing first gas volume flow (10b), wherein the feeders are formed separately from each other and each comprise at least one blower device (16a, 16b).

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