DE1776130A1 - Air-cooled condenser - Google Patents

Description

September 24, 1968 2738/12

BORSIG GmbH 1000 Berlin 2?

Air-cooled condenser

The invention "relates one by one inevitably moving air flow cooled condenser, in which at least two rows of approximately parallel and at a distance from one another lying condenser tubes arranged one behind the other in the flow direction of the cooling air, in parallel connection common steam distribution chambers are connected and connected to condensate collecting spaces. Most of them with each other Identical round or profiled condenser tubes are usually provided with ribs »on the outside are the condenser tubes drawn in from the atmosphere by a device that is inevitably moved, e.g. by a ventilator, Cooling air flow applied »

Capacitors are generally operated in such a way that the steam to be condensed flows into or around the pipes from above and the condensate flows downwards in the steam direction into the condensate drain.

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Air-cooled condensation systems of the type described above, especially those for precipitating turbine exhaust steam with tilting tube bundles, which are connected at the top to a common steam distribution line, so that the steam and condensate in each tube flow only in one direction, namely from top to bottom can cause sensitive malfunctions at cooling air temperatures below freezing point, for example in a vacuum system. In the case of turbine exhaust steam, for example, the condensation temperature is generally around 60 ° O, and usually even below that, ie the temperature difference between the water vapor condensate and its freezing point is relatively small. The condensate flows along the inner pipe wall down to the pipe mouth in the condensate chamber. As a result of the very unfavorable heat transfer conditions between condensate and cooling air in the lower part of the pipes, i.e. where steam condensation no longer takes place under certain operating conditions, a low pipe wall temperature also occurs at low outside air temperatures. On the other hand, at low outside air temperatures, the temperature difference between exhaust steam and cooling air is also relatively large, which means that the condensation ends at a greater distance from the lower pipe mouth ^! as

for example in the design point of the system »while the condensate has a formation temperature of, for example, 6D ^ G this relatively long way on the cold .inmeirem E®) jn * saad ii sud »& · & ♦ the Köadeasai has a! map« ferwsil & eii

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the unfavorable cooling effect on the lower half of the pipe it dissipates its heat until it solidifies on the cold pipe wall. It is well known that the risk of icing in the first row of tubes is greatest when viewed in Kühlluftriohtung, since the temperature here is greater than in all two steam and cooling air the rows of pipes behind, i.e. the condensate in the first row of pipes remains in the unfavorable cooling zone for a particularly long time. The same also applies to partial load operation, for example a condensation turbine. The condensation of the exhaust steam can soon after entering the upper muzzle should not be finished, since see the excess Cooling surface in partial load operation so that the larger Part of the lower half of the cooling surface is not touched by the exhaust steam. Also here the condensate has to go through a larger subcooling area. Regulating the amount of cooling air or switching off cooling surfaces can probably not improve the situation much if the outside air temperatures are not as great create, but at ambient temperatures from around -5 ° C this is in no way an effective measure against ice formation in the pipes «- uncontrollable wind influences increase the There is still a significant risk of icing in winter.

Bumps in the lower pipe mouths cause a pressure increase in the condenser and worsen it Vacuum considerably.

Ice plugs that form can burst the pipes and air ingress are the result. The system may even have to be taken out of service.

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Capacitors are known where the.

is arranged so that the steam only yon / uhl'en, .fn jäiß ... ^ ₁ '- ..;, ^; ^ Finned tube mouths can flow in, and / where aas sat near below, the near above flowing] £ ämpf, the condensate collecting chamber flows. This `` AÄeiran '' steam pipe, also known as dephlegmatorisqhe ^ S, prevents the condensate from being subcooled, since the warm steam flowing above keeps the condensate flowing in the opposite direction warm. This soJb should be used under certain operating conditions

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but then a safe measure to avoid pipes

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already indicated, only shown under V | (r | üi | e; | i ^^ | ^ "ari be applied when the flawless t'ä '!

tion system should be guaranteed. You have to pay attention to it care must be taken that the speed of the fDM |> | Ss at The flow into the lower pipe mouths is not too great. Excessively high steam velocities result in the pipe outlets' to an accumulation of the condensate flowing downwards. Pressure fluctuations in the condenser and intermittent drainage of the liquid and thus irregular operation, for example a vacuum system are the result. Permissible inflow velocities require a relatively small specific Volume of the steam to be condensed or a correspondingly large inlet cross-section of all pipe mouths. Vacuum vapors, especially turbine exhaust steam, but mostly have a

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relatively large specific steam volume, so that the inlet cross section of all pipe mouths is very large must be in order to allow a corresponding entry speed 'of the steam' at full load operation but require short tubes with a constant cooling surface. It is well known that they have devices and such air-cooled condensers with relatively short tubes also have the disadvantage that, for example, extensive chamber material, long pipes and a large number of small fans make the system expensive and uneconomical.

On the other hand, the construction of a capacitor is with Such short tubes are often not possible at all, because these short tubes with the diameter of the fans in no economic relationship can be achieved. For this reason, the dephlegmator operation is often not applicable at all.

Condensation systems are known which are inserted directly into the tube sheet of the steam distribution chamber or into the tubes Nozzles. These nozzles are in the direction of the flow of cooling air with an increasingly smaller cross-section of the passage through the pipe provided for the steam, so that a better distribution of the same on the individual rows of tubes is achieved and the pressure drop in the rear rows of tubes is increased * For only very specific operating conditions, this suggestion achieve that in the first acted upon by the cooling air

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If rows of pipes struck the condensation of the Daepfes shortly before their confluence with the Condensaftiaemf and thus an undercooling of the Koji4enea; t? J ^r ^ den. However, with such an air-cooled condenser, it is not possible to adapt to the respective operating conditions in such a way that the risk of freezing is eliminated, especially at low cooling air temperatures and low steam loads, since the excess cooling surface removes the condensation of the steam very far from the lower pipe mouths , end / t, is. In addition, the nozzles cause a large pressure loss on the steam side and thus create a poor vacuum.

Furthermore, an air-cooled condensation system is known in which the attached to the lower end of the tube bundle Condensate chambers in the direction of flow of the cooling air are divided into individual sub-chambers. These finned tube bundles in which the steam flows from top to bottom and condensed in the process, bundles of dephlegmators are arranged parallel on the air side and one behind the other on the steam side. The sub-chambers are individually and controllably connected to air suction devices. This is to achieve that the negative pressure decreases in the successive sub-chambers in the air direction, whereby the steam distribution to the rows of tubes connected to the individual sub-chambers according to the respective available temperature gradient between steam and cooling air is coordinated. The condensation should there-

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duroh. Ia all rows of pipes at a short distance from the in 41 · the associated subchamber terminating drilling ends ■ • in. The disadvantage here is that the exhaust steam from first condenses from top to bottom and the residual vapors only subsequently • reach the dephlegmator. It follows that at Seiila · tbetrieb, b.1. a condensation turbine and at Low cooling air temperatures, sioh an excess cooling layer in the condenser part located on the steam side, Helene divides the condensation of the exhaust steam not at a short distance from the tube ends opening into the lower chambers but at a very large distance. The adjustable I & ftabeaugvoriohtung helps There is no remedy since this is only possible with the The same condensation as possible in the individual rows of holes hold long sm, Jedooh it is under no circumstances possible with of the Ittftab * amgevorrichtung the coniases, once terminated in a large distance in the lower bore mouths, were laid below • La · «tendemmator with these facilities the desired Effect not achievable. Another disadvantage is that complex and failure-prone control devices are required for the air extraction

To avoid these Haohteile is according to the invention proposed that the steam distribution chambers and drilling lines aa the upper end of the Bippenrohrbündel and the am

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tint he connected to the Umführungeleitungen as en end combined Dampfverteiler- and Kondensatsammeikammern that the vapor in opposite direction the finned tubes major height tr ömt, welohe in a · "starry distance from the upper and lower Rohrmtindung away" transversely to Rohraohee in Röhrtei labeehnitt · Mind subdivided by condensate drains, which are connected to central pipes , which are in the Münden condensate chamber, eo deJ the condensation of the Bampfee in two separate sections with clear flow behavior in the pipes in opposite streams direction. The tube until the condensate in the upper section of the Rippenrohrbtindel iet vergleiohe weiee briefly so that the ore β Unterkühlungeetreoke at deep cooling air temperature is reduced to a minimum. Bas condensate from the upper half of the tube before it eioh supercooled and may freeze under certain circumstances, by the Kondensetobleiter the inner tube wall τοη detached and flows through the Zentralröhrohen the naoh upflow warm vapor in Bephlegmatbrteil meet and here the Bampf τοη still kept warm, which is particularly advantageous.

Another part of the gate by dividing the finned tubes across the pipe axis in two separate sections and due to the double-sided steam application is that compared to the known condenser designs, the steam has a large inflow crossover - for example

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double pipe cross-section - is available, whereby the pressure loss of the steam as it flows into the pipe mouths is reduced, making it economical Vacuum is achieved. Especially in summer operation, the previously known capacitors have a worse vacuum because they do not have the advantage just described.

It is also advantageous that when there is a small amount of steam, only the Dephlegmator part is in operation, which is precisely what it is for is suitable that it avoids freezing of the condensate. Even if in this case, i.e. with a small amount of steam, Should some steam still flow in from above, the path is through the condenser-operated finned tube bundle part shorter than "in the previously known designs, which take up the entire length of the pipe.

Another major advantage of the present embodiment over the previously known types is that not only the steam side is separated from each other, but also the condensate side. Because part of the condensate separated from the condensate by the central tubes flows out of the Dephlegmator part, the condensate build-up in the lower pipe mouths, i.e. at the steam inlet of the Dephlegmator, largely avoided.

In the present embodiment, there is no need for regulating devices and shut-off devices that can be used at temperatures would have to start below freezing in the known designs to prevent freezing.

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Another embodiment according to the invention is found is that the pipe sections, geaeseen sound the Condensate drains up to the respective pipe ends, eöwohl in the lower as well as in the upper pipe sections in the direction of flow of the steam before it enters the pipe mouths flows in, are gradually formed larger. This step-by-step larger design achieves that where the steam enters the finned tube bundle, the shortest tube length and thus the smallest cooling surface is available to the incoming steam. The finned tube bundle, which are furthest away from the steam inlet, seen in the direction of flow of the steam, have the larger ones Cooling surface. At full load and a relatively high inflow speed of the steam, the pressure on the steam side is

impact in the individual finned tube bundles so better distributed that between the incoming steam and the finned tube bundles lying away from it »with the increasing cooling surfaces an increasing pressure gradient builds up, which leads to the uneven flow conditions of the steam in the manifolds or pipelines and the different pressure losses in the pipe mouths are compensated for with one another.

With small amounts of steam, on the other hand, the steam is only condensed in the lower part of the dephlegmator, thus avoiding that a residual amount of steam through the connecting pipes breaks through into the condenser-operated tube bundle part, which in turn increases operational reliability.

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Let the single flow speed of the steam counter to the In the case just shown, relatively small, a gradation of the cooling surface can of course also be reversed Direction take place in a further embodiment according to the invention, so that the rib edges lying in the steam direction are subjected to this measure by the same dimensions as those behind them.

Another feature of the invention is ctasaf Drilled holes are placed in the central pipe below the condensate trap, so that the condensate below The inert air from both the upper part of the tubes through the tube mouths of the central tubes ir condensate drain, as auoh the lower section the pipes are sucked through the bores and flows together through the central agitator. Duroh this arrangement only ^ the The dephlegmator space or the cooling surface is used for drilling better used so that the condensate drain on this 8teUe is kept warm.

Is is known to have condensation in the first Row of pipes, seen in KUhlluftriohtung, in a larger distance tone of the lower pipe mouth terminates ale with the rows of pipes behind. In a further development of the invention, the pipe sections are measured ▼ from the condensate drain to the pipe openings in the upper one Steam dividing chamber, seen in cooling air direction, in each Row of tubes designed longer. By shortening the front rows of tubes of the condenser-operated part, is the condensate drain is brought closer to the end of the condensation and the path of the condensate on the cold inner wall of the pipe

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shortened and rather in the central tube in warn dephlegmator part introduced.

In the last row of tubes, seen in the air direction, let the Cooling surface in the condenser-operated part so large that the steam does not enter the central tubes of the dephlegmator part breaks through, but has already condensed. This ensures that the system is optimally designed.

In order to compensate for different thermal expansions of the individual tubes, according to the invention the central tube formed from two parts, the lower part with a larger diameter in the combined steam distribution and condensate collection chamber and covers the upper part of the central air tube.

In the drawing, the invention is explained using an example of execution *
Show it:

1 shows a condenser in a diagrammatic, schematic form Depiction,

Pig. 2 shows a section along line II - II in Pig. 1, Pig «3 the cross section of a condensate element in larger scale.

The one in the Pig. 1 and 2 shown capacitor consists of several roof-shaped capacitor elements, which at least one or, as shown here, three rows of approximately parallel and at a distance from one another arranged finned tube bundles 1, offset or

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one behind the other in the flow direction ^M d ″ of the cooling air. The finned tube bundle 1 is supplied with steam from below through the lower combined steam distribution and condensate collecting chamber 5. Steam is then also supplied to the finned tube bundles 1 from above via the transfer lines 3 and steam lines 2 Tube bundles are thus traversed by steam in the opposite direction. Of course, it is also possible, as not shown here, to connect the exhaust lines to the finned tube bundles in such a way that part of the steam is first condensed in the upper tube sections and the rest of the steam is condensed in the lower tube sections The steam can also be supplied in a manner not shown from a gable end of FIG. 1 through only one bypass line 3 so that the steam acts on the upper and lower pipe sections parallel or one behind the other and flows through them according to the invention in the opposite direction omt. The tubes are divided on the inside transversely to the tube axis into an upper 12a and lower 12b section by a condensate drain 14. The steam fed in from above through the steam distribution chambers 4 condenses in the upper partial pipe section 12 a and the condensate flows via the condensate drain 14 and central tubes 15 into the condensate collecting chambers 8.

The one from the combined steam distribution and condensate collection chambers 5 upwardly flowing steam condenses in the lower pipe section 12b and the condensate flows back into the aforementioned condensate collection chambers 5. The condensate

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is discharged from the condensate collection chambers 5 and 8 via the pipe socket 9 and the condensate lines 10 in the direction of the arrow "b". The inert air from the lower pipe sections 12b is via the bores -13, which are located just below the condensate drain 14 in the central tubes 15, together with the inert air from the upper pipe sections 12a through the central tubes 15, the condensate collecting chambers 8 and pipe sockets into the air lines 7 in the direction of the arrow "e", sucked off. Fig. 1 further shows the bulkheads 11 of the air condenser, which is supported by four supports 17, which are shown broken away at the lower end.

In Fig. 1 it is further shown that the pipe sections, measured from the condensate drain 14 to the respective pipe mouths, in both the upper and lower pipe sections 12a and 12b in the flow direction "a" of the steam, stepwise or as not shown here , are made continuously larger. The pipe sections, measured from the condensate drain 14 to the respective pipe mouths, both in the upper and in the lower pipe sections 12a and 12b viewed in the direction of flow "a" of the steam, can also be made smaller in steps, as not shown here.

Fig. 2 shows that the roof-shaped to each other arranged finned tube bundle 1 in cross section the sides of a roughly equilateral triangle form the base of one

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Axial fan 18 is formed. The finned tube bundle can also be arranged so that they are aenkreoht in the direction of the pipe axis old horizontally-arranged Yentilatoraohae, which is not shown here. Above of the axial fan 18, a gear 19 and a motor 20 are attached. The cooling air is, as indicated by the arrows "d", from at least one axial fan 18 conveyed from bottom to top or in the reverse direction, not shown, and flows past the outside of the smooth or finned tube bundle 1.

Fig. 3 shows the subdivision of the upper Rohrteilabsohnitte 12a, seen in the cooling air direction "d", are formed longer in each row of tubes. The steam trap 14 is thus brought closer to the end of the condensation in the upper tube part section 12a because it is displaced as is known, seen downwards in the cooling air direction. Thus, the path of the condensate on the cold inner wall of the Rohrteilabsohnittee 12a in the direction of the cooling air Rows of tubes in front shortened. Daa central tubes is formed from two parts, the lower part 16 being fastened with a larger durometer in the combined steam distribution and condensate collecting chamber 5 and the upper part of the central tube 15, which has a smaller Durohmesser, so covers that a labyrinth-like Diohtungsffekt occurs between them. This subdivision of the central tube compensates for the temperature expansion of the individual tubes.

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Claims (1)

September 24, 1968 2738/12 patent claims 1. Cooled by a forced air flow Condenser, in which at least two rows of approximately parallel and generally spaced condenser tubes one behind the other in the flow direction of the cooling air arranged, connected in parallel to a common steam distribution line and connected to a condensate air raid, characterized in that the steam distribution chambers (4) and pipes (2) at the upper end of the finned tube bundle (1) and the at the lower end combined steam distribution and condensate collection chambers (5) are connected to the bypass line (3) eo that the Daapf in opposite directions Direction the finned tubes (1) flows through, which at a certain distance from the upper and lower tube mouth removed, transversely to the pipe axis in pipe part sections (12a and 12b) are divided by a condensate drain part H, which is connected to a central tube (15), which opens into the condensate collection chamber (5), so that the condensation of the steam in two separate sections in mutually opposite flow - 17 -009840/0442 - 17 direction takes place. 2. Capacitor according to claim 1, characterized in that the Rohrteilabsohnitte, sat from the condensate drains (14) to the respective drilling outlets, both in the lower ones in the upper finned tube sections (12a, 12b) in the flow direction of the steam before it flows into the tubes, are made larger in steps (Pig. 1). 3. Capacitor according to claim 1, characterized in that the Rohrteilabsohnitte, measured from the condensate drain (H) to the respective pipe openings, both in the lower and in the upper finned tube bosses (12a, 12b) in the flow direction of the steam, before it flows into the tubes, are made smaller in steps. 4 · capacitor according to claim 1, characterized characterized in that bores (13) just below the condensate drain (14) in the central tubes (15) are attached so that the inert air from the lower condensate collection chamber (8) both from the upper sections (12a) of the pipes (1) through the pipe mouths the central tube (15) in the condensate drain (14), as is also sucked out of the lower sections (12b) of the tubes (1) through the bores (13) and through together the central tube (15) flows. - 18 - 009840/0442 5. Condenser according to claim 1 _f dad tt r ο h characterized in that the Rohrteilabsohnitte (12a, 12h), measured tob condensate drain (H) feie su the Rohrmtindungen in the upper DampfYteilerkajpmr (4), seen in Kühlluftriohtung, longer in each row of tubes are (Pig. 3). 6. The capacitor of claim 1 _V characterized in that the ZentralrQhrohen are formed (15) consists of two parts, the lower file are fixed (16) with a larger Durehmesser in Her combined Dampfverteiler- and KondensatsammeiTrη mmer (5) and the top the central tubes (15), which have a smaller diameter, are covered so that the different temperature expansion lengths of the single tubes (1) are compensated for (Fig. 3). 009840/0442