EP1996886B1 - Condenser which is exposed to air - Google Patents

Description

The invention relates to an air-charged capacitor having the features in the preamble of patent claim 1.

It is known that the pre-moistening of the cooling air, ie the so-called adiabatic cooling, can considerably increase the cooling capacity of air-cooled condensers, especially in summer operation. In particular, in larger plants in the power plant sector so far no practical and reliable solution to this problem could be found, such as HB Goldschagg in "Lessons learned from the world's largest forced draft direct cooled condenser", EPRI Conference, Washington DC, 01. - 03. 03. 1993 describes. On the other hand, the operators of such systems increasingly demand the provision of functional and efficient pre-wetting devices.

The major disadvantage of known adiabatic cooling is the soaking of the cooling elements, supporting structures and other plant components that are located below the cooling elements. The soaking of the cooling elements leads in the long term to an undesirable deposition of insoluble matter, while electrical components such as transformers must be fully protected against the ingress of moisture to avoid short circuits. The exact dosage of water and the distribution of water is very difficult to calculate, since the distribution of Water droplets depend, inter alia, on the wind direction and the temperature distribution An uneven distribution inevitably leads to local wetting and thus also to droplet formation, ie the water drips down on the capacitors and the supporting structure. This can cause unwanted corrosion even when using demineralized water.

From the US 2 655 795 A An air-charged condenser for generating a cooling air flow in the region of condensation elements is known. There is a fan provided. Furthermore, means for adiabatic cooling of the cooling air flow are provided, wherein the means for adiabatic cooling are feedable with water to be evaporated contact body, which are arranged in the region of the cooling air flow. It is proposed to arrange the means for adiabatic cooling in the intake of the cooling air flow in front of the fan.

The WO 03/006908 A describes a heat exchanger assembly for buildings, in which also means for adiabatic cooling are provided, which are upstream of the fans in the region of the cooling air flow. This is also in the DE 44 23 960 A1 and in the FR 1 254 045 A described.

Proceeding from this, the object of the invention is to improve an air-charged condenser in such a way that the condensation elements are not soaked by the means provided for adiabatic cooling of the cooling air and the means for adiabatic cooling can also be retrofitted with little effort.

This object is achieved by an air-charged capacitor having the features of patent claim 1.

The core of the invention is that the means for adiabatic cooling can be charged with water to be evaporated contact body, which are arranged in the region of the cooling air flow, that is on the downstream side of the condensation elements. The contact bodies have a large surface on which water introduced into the contact bodies can evaporate. The water is located At no time free within the cooling air flow, as is the case with a spraying by means of nozzles. Unlike nebulization or spraying, virtually no excess water is required since the water taken up in the contact body is transferred to the cooling air flow exclusively through mass transfer, ie evaporation. This also ensures that corrosion damage caused by unwanted moistening of nearby components, such as the fan, is avoided.

In the case of the air-cooled condensers designed according to the invention, a significant increase in performance is expected with a moderate increase in investment costs. New plants to be built can be smaller even with a given power, if an adiabatic cooling is provided by means of Kontaktkörpem. As a result, the manufacturing costs of new Anla are expected to be reduced. Another advantage is that, for example, can be reduced by hot air recirculation-related performance deficiencies, on the other hand, the performance of a power plant by reducing the turbine steam pressure can be increased by some 10 kPa.

Advantageous embodiments of the inventive concept are the subject of the dependent claims.

The air-charged condenser according to the invention is preferably provided for the condensation of water vapor. In particular, these are condensers for condensing the exhaust steam flow from a turbine of a power plant. In principle, however, it is also conceivable that the air-charged capacitors for the condensation of other substances, such as for the condensation of propane, are provided. The inventive concept is not limited to the condensation of water vapor. Likewise, the air-charged capacitor according to the invention is not limited to a specific type of capacitor. In principle, the contact bodies which can be charged with water to be evaporated can be used in combination with A-shaped, V-shaped, vertically or horizontally arranged condensation elements. The use of such contact bodies in connection with A or roof-shaped condensation elements is considered to be particularly favorable.

The contact bodies are also in the exit region of the cooling air flow from the fan, i. arranged in Kühtluftstromrichtung behind the fan.

A further variant provides that contact bodies are arranged directly in front of the condensation elements and cover at least part of the inflow surface of the condensation elements. The contact body can cover the entire Anströrnfläche the condensation elements or even a wedge surface. It is conceivable that e.g. only some of the condensation elements are provided with Kontaktkörpem, others, however, not. Partial coverage of the condensation elements may be e.g. in the upper, middle or lower third. The respective degree of coverage and the exact positioning of the contact bodies must be made dependent on the local conditions. Here can not be called a rigid rule.

It is considered to be particularly advantageous if the degree of coverage of the inflow surface is adjustable by displacement of the contact body. In the event that the contact bodies are inactivated, i. that no prehumidification of the cooling air is desired, these could e.g. be pivoted and taken in a certain way out of the cooling air flow, so that a larger flow surface of the condensation elements is released for pure dry cooling. The swinging out also has the advantage that no additional pressure loss caused by the contact body.

The axis about which the contact bodies are pivoted, depends on the spatial conditions. For example, in the case of condensation elements arranged in an A-shape, the pivot axis in the ridge region, that is to say essentially horizontal, but at least parallel to those of the con condensation elements spanned levels. It is also conceivable that the pivot axis is not horizontal, but runs parallel to the planes spanned by the condensation elements, that is to say in the case of condensation elements arranged in an A-shape, in accordance with the inclination of the condensation elements. If the spatial conditions permit, the contact bodies can also be arranged to be translationally displaceable.

It is considered particularly favorable if contact bodies are fastened directly to the condensation elements on their sides facing the fan. The contact bodies may e.g. be attached to the end faces of the transversely ribbed tubes of the condensation elements. The attachment of contact bodies directly to the condensation elements only leads to a negligible increase in the flow resistance, so that no pressure losses occur. Nevertheless, the Köntaktkörper are completely within the cooling air flow. As with the arrangement of Kontaktkörpem in the flow direction in front of the condensation elements attached directly to the condensation elements contact body can be provided only in partial areas. For example, every second tube of the condensation elements could be provided with contact bodies.

The contact bodies are preferably a fleece, a fabric or a porous plastic. The essential characteristics of having suitable contact bodies are high storage capacity for water and a large surface area to allow rapid evaporation of the water. In addition, the material used should have sufficient air permeability, depending on the arrangement within the cooling air flow, in order to limit the pressure losses. Self-supporting materials are considered to be particularly advantageous, and combined multi-layer materials may be used, wherein one position of the contact body fulfills the support function and at least one other layer is designed specifically for water absorption and high evaporation. Common and inexpensive available on the market are geotextiles or Nonwovens that provide the desired absorbency and good evaporation of water. The materials mentioned have a high resistance to aging and are also mechanically sufficiently resistant. The contact bodies can preferably be cleaned after a predetermined period of use and then reused. The contact body should therefore not decompose under the influence of air and water. By a suitable choice of material both a high mechanical strength and at the same time a corresponding desired water absorption capacity can be achieved. Both are prerequisites for use within the cooling air flow in air-cooled condensers. The contact bodies are preferably formed as flat plates. Of course, it is possible that one-piece or multi-layer contact bodies deviate in their geometry from flat plates, ie, for example, are wavy or are adapted in their contouring to the flow conditions of the air-cooled condenser or are intended by their positioning and contouring influence on the flow conditions to take. This means that the contact bodies can also have a certain conductive or deflecting function with respect to the cooling air flow, depending on the positioning and contouring.

It is essential in the condenser according to the invention that the amount of water to be introduced into the contact bodies is selected such that no significant excess is produced, which would lead to a wetting of the installation. Therefore, a metering system controlling the amount of water to be introduced into the contact bodies is provided, which precisely supplies the contact body with precisely the amount of water which has to be supplied under the given climatic conditions and operating conditions of the system in order to ensure maximum evaporation in the area of the contact bodies. This may be a control circuit or a control circuit equipped with corresponding measuring devices. The measuring devices detect whether at certain measuring points outside the contact body water is present, which suggests that the contact bodies too much water has been supplied to the evaporation.

In order to improve the distribution of the water within the contact body, it is provided that adjacent to a contact body, a metering line extends with a plurality of openings through which the water to be evaporated can be introduced into the contact body. This may be a rigid or flexible line that runs in the edge region of the contact body. By way of gravity, such a dosing line can introduce water, for example from above, into a contact body. The water runs down inside the contact body, wets its surface and evaporates within the cooling air flow. The amount of water is metered so that it passes on its way through the contact body straight to the lower end and partially evaporated already on the way there. It is also conceivable that the metering lines are arranged on the cooling air flow facing or facing away from the surface of the contact body. As a result, the distance that the water has to cover within a plate-shaped contact body is shorter and it ensures a more even distribution of the cooling water, which also simplifies the dosage. It is considered to be particularly advantageous if the metering line is embedded in the contact body. This can be realized, for example, by a meandering dosing line which is positioned, for example, between two contact bodies formed as a nonwoven. Through the metering both contact bodies are wetted equally with water. The risk of water escaping uncontrollably from the fleece is thereby minimized.

Furthermore, it is considered advantageous if the water to be evaporated is preheated in the metering, by heat transfer from the condensation elements to the metering. For this purpose, the metering lines can extend between the end faces of the condensation elements and the contact bodies attached to the end faces. The preheated in this way water extracts the condensing elements to a small extent heat and evaporates faster in the contact body. This increases the efficiency of such an air-charged capacitor.

Figur 1

eine schematische Darstellung eines luftbeaufschlagten Kondensators in A-Form bzw. Dachbauweise mit zusätzlichen Kontaktkörpem zur Wasserverdunstung;

Figuren 2bis 4

weitere Ausführungsformen eines Trockenkühlers in Dachbauweise mit anderen Anordnungen der Kontaktkörper,

Figur 5

eine perspektivische Darstellung eines Kondensationselements mit daran befestigten Kontaktkörpem;

Figur 6

ein Ausführungsbeispiel eines Kontaktkörpers mit einer mäanderförmig verlaufenden Dosierleitung in der Draufsicht;

Figur 7

den Kontaktkörper der Figur 1 im Längsschnitt und

Figur 8

eine weitere Ausführungsform eines Kontaktkörpers mit einer Dosier- leitung.

The invention is described below with reference to the embodiments illustrated in the schematic drawings of FIGS. 2 to 8 explained in more detail. The other, described below FIG. 1 is merely illustrative of the claimed invention and is not an embodiment of the invention for which protection is sought. Show it:

FIG. 1

a schematic representation of a luftbeaufschlagten capacitor in A-form or roof construction with additional Kontaktkörpem for water evaporation;

FIGS. 2 to 4

Further embodiments of a dry cooler in roof construction with other arrangements of the contact body,

FIG. 5

a perspective view of a condensation element attached thereto Kontaktkörpem;

FIG. 6

an embodiment of a contact body with a meandering dosing line in plan view;

FIG. 7

the contact body of FIG. 1 in longitudinal section and

FIG. 8

a further embodiment of a contact body with a metering line.

FIG. 1 shows an A-type air-powered condenser 1, as known in its basic form from the prior art. Such an air-cooled condenser 1 is mounted on a steel framework, not shown, so that cold cooling air can be sucked in a cooling air stream 3 by a fan 2 from below and in the limited by the condensation elements 4, 5, triangular interior 6. The cooling air flows through the condensation elements 4, 5 designed as finned tube bundles and is heated in this case. At the same time, the steam flowing through the condensation elements 4, 5 is cooled and condensed. In this first exemplary embodiment, a contact body 7 is in the intake region 8 of the ventilator 2 arranged. The cooling air is pre-moistened by the contact body 7. The cooling air flows through the contact body 7, which is fed in a manner not shown with water. In the contact body 7 acts it is preferably a non-woven or a porous structure made of a plastic. The introduced water is transferred by mass transfer to the cooling air, so that can be significantly increase the cooling capacity of the air-cooled condenser 1, especially in summer operation.

In the embodiment of the FIG. 2 is a contact body 7a in the outlet region 9 of the cooling air flow 3 from the fan 2, that is, it is located in the interior 6 between the condensation elements 4, 5.

A third variant shows FIG. 3 , There, a contact body 7b is provided, which can be pivoted between two positions A, B. In this way, the degree of coverage of the inflow surface 10 of the condensation elements 4, 5 can be changed. As a result, the pressure loss, which inevitably occurs when flowing through the contact body 7b, can be changed. In particular, when the connection of the contact body 7b is not required, it can be displaced from the position A to the position B.

FIG. 4 shows an embodiment with a contact body 7c, which is pivotable about a pivot axis S. As a result, the contact body 7c can be displaced into the position shown in broken line. In contrast to the embodiment of FIG. 3 is at the in FIG. 4 variant may be expected under a circumstance with a smaller influence on the flow behavior. Of course, it is also conceivable that the contact body 7c is arranged on the other condensation element 4, wherein the pivot axis S then of course runs parallel to this condensation element 4.

As a particularly advantageous embodiment of the FIG. 5 considered. FIG. 5 shows a perspective view of the condensation element 4 in the direction from the interior 6 out. The condensation element 4 comprises a series of juxtaposed tubes 11, which are traversed by water vapor. The tubes 11 have an elongate, almost rectangular cross section, wherein between the mutually facing transverse sides 12 of the tubes 11 are ribs 13, which are flowed around by the cooling air flow 3. The special feature of the illustrated condensation element 4 is that 14 contact bodies 7d are attached to the respective unaffected end faces, which are exemplified by the hatching drawn. Such contact bodies 7d are not present laterally in the finned gap, ie they do not reduce the flow cross section between the tubes 11. Nevertheless, there is an intensive exchange with the passing cooling air, which is moistened when flowing past.

In all the preceding figures, the representation of one or more metering lines for feeding the contact body with water was dispensed with. The FIGS. 6 to 8 show flat contact body in different representations, which essentially depends on the arrangement of the metering 15. In the FIG. 6 dosing line 15 shown extends on the surface of the illustrated contact body 7e. The metering line 15 has a plurality of openings, not shown, through which the water to be evaporated is introduced into the contact body 7e. The meandering course ensures a uniform introduction of water into the contact body 7e.

FIG. 7 shows the contact body 7e of FIG. 5 in longitudinal section. It can be seen that the metering line 15 in this exemplary embodiment directly adjoins the schematically indicated condensation element 4, so that the heat prevailing in the condensation element 4 is transferred to the metering line 15 and thus to the water to be evaporated.

In contrast, in the embodiment of the FIG. 8 the dosing line 15 approximately in the middle of the illustrated contact body. This variant in turn has the advantage that the water to be evaporated must first pass through the illustrated contact body 7e before it reaches the surface of the contact body 7e. On the way to the outer surface of the contact body 7e this is wetted.

It is also conceivable that the metering line is embedded between two Kontäktkörpern, wherein the water to be evaporated is discharged on both sides of the metering.

Reference numerals:

1 -

capacitor

2 -

fan

3 -

cooling air

4 -

condensation element

5 -

condensation element

6 -

inner space

7 -

Contact body

7a -

Contact body

7b -

Contact body

7c -

Contact body

7d -

Contact body

7e -

Contact body

8th -

suction

9 -

exit area

10 -

inflow area

11 -

pipe

12 -

transverse side

13 -

rib

14 -

Front side v. 11

15 -

dosing

A -

Position v. 7b

B -

Position v. 7b

Claims (15)

1. Aerated condenser, with which at least one fan (2) is associated for generating a flow of cooling air in the region of condensation elements (4, 5), and wherein means for the adiabatic cooling of said flow of cooling air (3) arc provided, wherein said means for adiabatic cooling are contact bodies (7, 7a, 7b, 7c, 7d, 7e) which can be charged with water which is to be evaporated and which are arranged in the region of the flow of cooling air (3),
   characterised in that
   contact bodies (7a) are arranged in the region in which the flow of cooling air (3) passes out of the at least one fan (2).
2. Aerated condenser according to claim 1,
   characterised in that
   the condensation elements (4, 5) are designed for condensing water vapour.
3. Aerated condenser according to claim 1 or 2,
   characterised in that
   contact bodies (7b, 7c) are arranged directly in front of the condensation elements (4, 5) and cover at least part of that face (10) of the condensation elements (4, 5) against which the flow impinges.
4. Aerated condenser according to claim 3,
   characterised in that
   the degree to which the face (10) against which the flow impinges is covered can be adjusted by moving the contact bodies (7b, 7c).
5. Aerated condenser according to claim 1,
   characterised in that
   the contact bodies (7b, 7c) arc pivotable.
6. Aerated condenser according to one of claims 1 to 5,
   characterised in that
   contact bodies (7d) are fastened directly to the condensation elements (4, 5) on the sides of the latter that face towards the incoming flow of cooling air (3).
7. Aerated condenser according to claim 6,
   characterised in that
   the contact bodies (7d) are fastened to the end faces (14) of tubes (11) of the condensation elements (4, 5), which tubes are provided with fins (13) on the transverse sides (12).
8. Aerated condenser according to one of claims 1 to 7,
   characterised in that
   the contact body is a non-woven fabric.
9. Aerated condenser according to one of claims 1 to 8,
   characterised in that
   the contact body is a porous plastic.
10. Aerated condenser according to one of claims 1 to 9,
    characterised in that
    a metering system which controls the quantity of water to be introduced into the contact bodies is provided.
11. Aerated condenser according to claim 10,
    characterised in that
    the quantity of water introduced into the contact bodies by the metering system is not greater than the quantity of water to be evaporated.
12. Aerated condenser according to either of claims 10 or 11,
    characterised in that
    a metering line (15) having a number of apertures through which the water to be evaporated can be conducted into the contact body (7e) extends adjacently to said contact body (7e).
13. Aerated condenser according to one of claims 10 to 12,
    characterised in that
    a metering line (15), which has a number of apertures through which the water to be evaporated can be conducted into the contact body (7e), is embedded in the contact bodies (7e).
14. Aerated condenser according to either of claims 12 or 13,
    characterised in that
    the water to be evaporated is preheated in the metering lines (15) by the transfer of heat from the condensation element (4) to said metering lines (15).
15. Aerated condenser according to claim 14,
    characterised in that
    the metering lines (15) extend between the end faces (14) of the condensation elements and the contact bodies (7e) fastened to said end faces (14).

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