ES2904829T3 - Fully Secondary Air Cooled Industrial Steam Condenser - Google Patents

Abstract

A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles connected to an industrial steam production facility, comprising: two bundles (4), each comprising a plurality of flattened tubes with fins (2) placed adjacent to each other, each of said bundles oriented so that the longitudinal axis of said flattened tubes with fins is positioned at an angle of 55°-65° from the horizontal; a combined steam distribution-condensate collection header (6) attached to a bottom of each of said bundles and extending along a length of said bundles configured both to deliver steam to a bottom of said tubes as for collecting condensate that forms in said tube from said steam while cooling; a non-condensable collection header (8) attached to the top of each of said bundles and extending along a length of said bundles parallel to said vapor distribution header and configured to collect non-condensable gases from said vapor, wherein the condenser does not comprise primary condenser tubes

Description

DESCRIPTION

Fully Secondary Air Cooled Industrial Steam Condenser

Background of the invention

field of invention

The present invention relates to large-scale field-assembled air-cooled industrial steam condensers.

Description of the background

The finned tube currently used in most large-scale field-assembled industrial air-cooled vapor condensers ("ACC") uses a flattened tube that is approximately 11 meters long by 200 mm wide (also known as "air stroke length") with semi-circular inlet and outlet edges, and an internal height of 18.8 mm (perpendicular to the air stroke length). The tube wall thickness is 1.35mm. Fins are welded to both flat sides of each tube. Fins are typically 18.5mm high, spaced at 11 fins per inch. The fin surface has a wave pattern to improve heat transfer and aid fin stiffness. The standard space between the tubes, center to center, is 57.2 mm. The tubes themselves make up about one-third of the cross-sectional face area (perpendicular to the airflow direction); while the fins make up nearly two-thirds of the cross-sectional face area. There is a small gap between the tips of the adjacent fins of 1.5mm. For summer ambient conditions, the maximum velocity of steam through the tubes can typically be as high as 28 mps, and more typically 23 to 25 mps. The combined design of a single A-frame along with these tubes and fins has been optimized based on tube length, fin spacing, fin height and shape, and air path length. Finned tubes are assembled into heat exchanger bundles, typically 39 tubes per heat exchanger bundle, and 10 to 14 bundles are arranged in two heat exchangers arranged together in a single A-frame per fan. The fan is typically below the A-frame and draws air up through the bundles. The overall tube and fin design, and the air pressure drop of the tube and fin combination, has also been optimized to match the air moving capacity of large fans (36 ft. diameter) operating between 200 and 250 hp. This optimized layout has remained relatively unchanged across many different manufacturers since the introduction of the single row elliptical tube concept over 20 years ago.

The typical A-frame ACC described above includes 1' stage or "primary" capacitor bundles and 2' stage or "secondary" bundles. Approximately 80% to 90% of heat exchanger bundles are primary or 1' stage condenser bundles. Steam enters at the top of the primary condenser bundles and condensate and some steam leaves at the bottom. The first stage configuration is thermally efficient; however, it does not provide a means of removing non-condensable gases. To sweep non-condensable gases through the 1' stage bundles, 10% to 20% of the heat exchanger bundles are configured as 2' stage or secondary bundles, usually sandwiched between the primary bundles, which draw steam from the lower condensate collector. In this arrangement, steam and non-condensable gases travel through the 1' stage bundles as they enter the bottom of the secondary bundle. As the gas mixture rises through the secondary bundle, the rest of the vapor condenses and concentrates the non-condensable gases. The tops of the branch bundles are attached to a vacuum manifold that removes non-condensable gases from the system.

Variations to the standard prior art ACC arrangement have been disclosed, for example, in US 2015/0204611 and US 2015/0330709. These applications show the same finned tubes, but drastically shortened and then arranged in a series of small A-frames, typically five A-frames per fan. Part of the logic is to reduce vapor pressure drop, which has little effect on overall capacity in summer conditions, but a larger effect in winter conditions. Another part of the logic is to weld the upper vapor header duct to each of the bundles at the factory and ship them together, thus saving costly field welding. The net effect of this arrangement, with the vapor collector installed at the factory and shipped with the tube bundles, is a reduction in tube length to accommodate the collector in a standard high cube shipping container. Because the tubes are shorter and therefore the total amount of surface area is reduced, the comparative capacity with the standard single A-frame design summer condition of similar overall dimension, is reduced by approximately 3 %. Examples of other known air-cooled condenser systems include EP0346848, US4949543,

US4926931 and US3204693. No part of the prior art discloses an air-cooled condenser without primary condenser tubes.

Summary of the invention

According to the invention, there is provided a large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles as claimed in claim 1. Features presented in the present description include 1) a new tube design for use in heat exchanger systems, including, but not limited to, large-scale field-assembled industrial steam condensers; and 2) a new design for large-scale field-mounted industrial steam condensers for power plants and the like, both of which significantly increase the thermal capacity of the ACC while, in some configurations, reducing material. Various other aspects and/or embodiments of the inventions are set forth below:

According to various embodiments of the tube design invention, the tubes are 2.044 m long, the cross-sectional dimensions of the tubes are 100-200 mm wide, preferably 125 mm wide (run length of air) with a cross-sectional height (perpendicular to the length of the air path) of less than 10 mm, preferably 4-10 mm, more preferably 5.0-9 mm, even more preferably 5.2- 7mm, and most preferably 6.0mm in height (also "external tube width"), with fins being provided from 9 to 12, preferably 9.8, fins per inch, corresponding to 3.54 to 4 .72, preferably 3.86 fins per centimeter. According to another preferred embodiment, the actual fins may be 17-20mm high, preferably 18.5mm high and span the space between two adjacent tubes, effectively making 9.25mm of fin available for each tube. tube on each side

Making tubes of smaller cross-section (same air path length, but significantly less height) is directly contrary to the prevailing current opinion in the art that tubes should be made with as large a cross-section as possible. to accommodate the massive volumes of steam produced by a large-scale power plant, and because larger tubes reduce costs. Although the cost of this arrangement is significantly higher than the prior art tube arrangement, the inventors unexpectedly found that the efficiency gains with the shorter tubes (in the most preferred embodiment exceed 30% more efficiency compared to with prior art tubes) more than offset the increased cost. This new tube design can be used in prior art large-scale field-assembled industrial steam condensers (eg, as described in the background section), or it can be used in conjunction with the new design of ^a C ^c described herein below.

Turning to the new design for large-scale field-assembled industrial steam condensers, the main feature of this invention is that all tube bundles of ACCs according to this invention are constructed as secondary tube bundles, since the steam is upwardly oriented tubes (aligned parallel to the cross axis of the bundle, each tube generally oriented at 25°-35°, and preferably 30° from vertical) are fed from the bottom and condensate is collected from the bundles from the bottom, preferably by using a combination/hybrid collector that supplies steam to the tubes and collects condensate from the tubes. According to one embodiment, the combination/hybrid collector can be constructed so that condensate is prevented from returning via the steam supply risers and instead is delivered to a condensate recovery pipe connected to the combination/hybrid collector. . According to an alternative embodiment, the combination/hybrid collector can be constructed so as to allow condensate to travel down the steam supply risers and withdraw from the steam supply line closer to the ground. The upper parts of the tubes are connected to a separate collector to collect the non-condensable gases. This new "full secondary" ACC arrangement can be configured in an A-frame, with two secondary bundles joined at the top with a single collector collecting non-condensable gases from the tubes, or with two non-condensable collectors, one on top. the top of each beam.

As used herein, the terms "wholly secondary" and "non-primary" shall refer to large-scale, field-assembled, air-cooled industrial steam condensers in which all tube bundles receive steam from the bottom and collect condensate at the bottom, and supply non-condensable gases exiting at the top. By comparison, the primary tube bundles in a large-scale field-assembled air-cooled industrial steam condenser receive steam at the top, deliver condensate at the bottom, and deliver non-condensable gases at the bottom to a separate secondary condenser. .

Preferably, however, the ACC of the invention may be arranged in a V configuration where two secondary-only condenser bundles are joined at the bottom with a unique combination steam distribution manifold/condensate collection manifold, with a separate non-condensable collection collector at the top of each bundle.

In accordance with the preferred V-configuration embodiment, since the vapor collector is at the bottom of the bundles, entering the collector at more than one location reduces the size of the collector and allows the finned tubes to be slightly smaller. longer. When combined with smaller cross section tubes described herein (200mm by less than 10mm, preferably 4-10mm, more preferably 5.0-9mm, even more preferably 5.2-7mm, and most preferably 6.0 mm in height), the system shows performance improved by at least 25 % to 30%, relative to the standard ACC layout and configuration described above, and the unit can be made smaller by a similar amount in plan area.

According to a further alternative embodiment, the new ACC design of the present invention can be used with tubes having dimensions of 100mm by preferably 4-10mm, more preferably 5.0-9mm, even more preferably 5.2 -7mm, and most preferably 6.0mm high, with offset fins.

According to another embodiment, the new ACC design of the present invention can be used with 120mm or up to 200mm tubes by 5mm to 7mm having "arrowhead" fins arranged at 9.8 fins per inch. , corresponding to 3.86 fins per centimeter.

According to yet another embodiment, the new ACC design of the present invention can be used with tubes having "louvered" fins, which work approximately as well as offset fins, and are more readily available and easier to manufacture.

In accordance with the preferred and most preferred embodiments of the invention, combining the most preferred ACC configuration and the most preferred tube dimensions, an ACC of the present invention has the following characteristics and dimensions:

• All secondary bundles (all tubes receive steam from the bottom, distribute condensate to the bottom, and distribute non-condensable gases to the top); no primary bundles;

Four, five (most preferred), or six V-shaped bundle pairs per cell/fan;

Tube outside dimension 4-10mm (preferred 5-7mm and more preferred: 6.0mm) by 100-200mm (most preferred 125mm) cross-section;

Tube spacing c-c 20-29 mm (most preferred: 24.5 mm);

Tube wall thickness 0.7-0.9 mm (most preferred: 0.8 mm);

Tubes per bundle = 40-60 (more preferred 50);

Tube length 1700-2400 mm (most preferred 2044 mm);

Arrowhead fins (preferred, not required) extending between adjacent tubes and thermally connected to both tubes;

Fin height 17-19 (most preferred 18.5mm (effective height 9.25mm per tube side);

Air travel length fins 95mm -195mm, most preferred: 120mm.

According to this most preferred embodiment, the total beam face area versus prior art ACC having the same total fan power, steam volume and thermal conditions is 79%; likewise, the total plan area for this most preferred embodiment is 79% of the area of the prior art ACC having the same total fan power, steam volume and thermal conditions.

Furthermore, the ACC design of the present invention can be more easily located, requiring less overall space within the power plant.

Brief description of the drawings

Figure 1A is a perspective view representation of the heat exchange portion of a prior art large scale field assembled industrial steam condenser. Figure 1B is a close-up partial exploded view of the heat exchange portion of a prior art large-scale field-assembled industrial air-cooled steam condenser, showing the orientation of the tubes relative to the header. steam distribution.

Figure 2 is a perspective view representation of the heat exchange portion of a large-scale field-assembled industrial air-cooled vapor condenser ("ACC"), in accordance with a first embodiment of the invention.

Figure 3 is a perspective view representation of the heat exchange portion of a large-scale field-assembled industrial air-cooled vapor condenser ("ACC") in accordance with a second embodiment of the invention.

Figure 4A is a perspective view representation of the heat exchange portion of a large-scale field-assembled industrial air-cooled vapor condenser ("ACC") in accordance with a third embodiment of the invention.

Figure 4B is a perspective view representation of the heat exchange portion of a large-scale field-assembled industrial air-cooled vapor condenser ("ACC") in accordance with a fourth embodiment of the invention.

Figure 5 is a cross-sectional perspective view of a prior art ACC tube and fins.

Figure 6 is a perspective view of a minitube and fins according to one embodiment of the invention.

Figure 7 is a perspective view of minitubes and fins according to another embodiment of the invention.

Figure 8 is a side lane view of a large-scale field-assembled industrial air-cooled steam condenser in accordance with one embodiment of the invention with a V-shaped secondary-only heat exchange bundle pair arrangement shown in Figure 4A. Figure 9 is an end view of the large-scale field-assembled industrial air-cooled steam condenser shown in Figure 8.

Figure 10 is a top view of the large-scale field-assembled industrial air-cooled steam condenser shown in Figure 8, showing a turbine exhaust duct divided into 6 longitudinal steam headers (6 lanes) of 6 cells each. one.

Figure 11 is a perspective view drawing of a secondary condenser finned tube bundle according to one embodiment of the invention.

Figure 12 is a perspective view photograph of the secondary condenser finned tube bundle depicted in the drawing of Figure 11.

Detailed description of the invention

A-frame ACC with all sub beams

With reference to Figure 2, the tubes 2 are arranged in the secondary bundles 4. The longitudinal axes of the tubes 2 are aligned parallel to the transverse axis of the tube bundle, each tube generally oriented at 25°-35°, and preferably at 30°, from the vertical). Combination steam distribution/condensate collection manifolds 6 are attached at the bottom of each of two branch bundles 4 which are attached at their top in an A-frame configuration. Steam is distributed to the tubes 2 through the combined steam distribution/condensate collection manifolds 6, with condensate forming in tubes 2 as the steam condenses and travels down tubes 2 to the combined steam distribution/condensate collection manifold. 6. A single non-condensable collection manifold 8 is attached to the top of both bundles 6 to collect non-condensable gases traveling to the top of tubes 2. Steam is supplied to the combined steam distribution manifold /condensate collection 6 from the steam line 10 through risers 12. The condensate that accumulates in the combined steam distribution / condensate collection manifold 6 is drawn from the ACC in condensate recovery tube 14. Figure 3 shows an embodiment very similar to the embodiment of Figure 2, except that each bundle 4 is attached at its top to a dedicated non-condensable collection manifold.

V-shaped ACC with all secondary beams

With reference to Figures 4A and 4B, the tubes 2 are arranged in the secondary bundles 4. The longitudinal axes of the tubes 2 are aligned parallel to the transverse axis of the tube bundle, each tube generally oriented at 25°-35° , and preferably at 30°, from the vertical). A combination steam distribution/condensate collection manifold 6 is attached at the bottom of two branch bundles 4 which are attached in a V-shape at an angle of 55°-65°, preferably 60°. Steam is distributed to tubes 2 through the combined steam distribution/condensate collection header 6, and condensate forms in tubes 2 as the steam condenses and travels down tubes 2 to the combined steam header. steam distribution/condensate collection 6. A non-condensable collection header 8 is attached to the top of both bundles 6 to collect non-condensable gases traveling to the top of tubes 2. Steam is supplied to the header combined steam distribution/condensate collection manifold 6 from the steam line 10 through risers 12. The condensate that accumulates in the combined steam distribution/condensate collection manifold 6 is drawn from the ACC in the recovery tube condensate 14. The new ACC design described above can be used with any prior art tube, including the tubes shown in Figure 5 having a length of ap approximately 11 meters long and a width (or "airpath length") of 200mm with semi-circular leading and trailing edges, and having an internal height (perpendicular to the airpath length) of 18.8mm and 1.35mm tube wall thickness, with fins welded to both flat sides of each tube, typically 18.5mm high, spaced at 11 fins per inch. However, according to a more preferred embodiment, the new ACC design of the present invention has the following characteristics and dimensions:

• All secondary bundles (all tubes receive steam from the bottom, distribute condensate to the bottom, and distribute non-condensable gases to the top); no primary bundles;

• Four, five (most preferred) or six V-shaped bundle pairs per cell/fan;

• Tube outside dimension 4-10mm (preferred 5-7mm and more preferred: 6.0mm) by 100-200mm (most preferred 125mm) cross-section;

• Space between tubes c-c 20-29 mm (most preferred: 24.5 mm);

• Tube wall thickness 0.7-0.9 mm (most preferred: 0.8 mm);

• Tubes per bundle = 40-60 (most preferred 50);

• Tube length 1700-2400 mm (most preferred 2044 mm);

• Arrowhead fins (preferred, not required) that extend between adjacent tubes and are thermally connected to both tubes;

• Fin height 18.5 mm (effective height 9.25 mm per tube side);

• Air travel length fins 95mm-195mm, most preferred: 120mm.

According to this preferred embodiment, a 25-30% increase in capacity over the prior art A-frame design with standard tubes is provided for a single cell with constant fan power.

Figures 8-10 show a representative large-scale field-assembled industrial air-cooled steam condenser in accordance with one embodiment of the invention with V-shaped secondary-only heat exchange bundle pairs shown in Figure 4A. The device shown in Figures 8-10 is a 36-cell ACC (6 lanes x 6 cells), with the most preferred embodiment being five beam pairs per cell, but the invention can be used with any ACC size and number. of beam pairs per cell.

Claims (16)

1. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles connected to an industrial steam production facility, comprising: two bundles (4), each comprising a plurality of flattened finned tubes (2) positioned adjacent to each other, each of said bundles oriented such that the longitudinal axis of said flattened finned tubes is positioned at an angle of 55 °-65° from horizontal; a combined steam distribution-condensate collection header (6) attached to a bottom of each of said bundles and extending along a length of said bundles configured both to deliver steam to a bottom of said tubes as for collecting condensate that forms in said tube from said steam while cooling; a non-condensable collection header (8) attached to the top of each of said bundles and extending along a length of said bundles parallel to said vapor distribution header and configured to collect non-condensable gases from said steam, wherein the condenser does not comprise primary condenser tubes 2. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles according to claim 1, wherein all condensate collected from said tubes (2) is collected in said combined condenser steam distribution-condensate collection (6). 3. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein all steam supplied to said tubes (2) is supplied from said combined header steam distribution-condensate collection (6). 4. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles according to claim 1, wherein the longitudinal axis of said flattened finned tubes (2) is positioned at an angle 60° from the horizontal. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles according to claim 1, wherein said two bundles (4) are arranged in an A-frame configuration with a single non-condensable collection collector (8) attached to the upper parts of both of said bundles and with a separate combined condensate collection-steam distribution collector (6) connected to the lower parts of both of said two bundles. 6. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles according to claim 1, wherein said two bundles (4) are arranged in an A-frame configuration with two non-condensable collection collectors (8), each one attached to the upper part of one of said two bundles, and with two combined condensate collection steam distribution collectors (6), each one attached to the lower part of one of said two bundles. said two do. 7. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles according to claim 1, wherein said two bundles (4) are arranged in a V-shape with a single combined manifold steam distribution-condensate collection manifold (6) connected to the lower parts of both of said two bundles and with two separate non-condensable collection manifolds (8), one attached to the upper part of each of said two bundles. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have a cross-sectional width of 100mm - 200mm and a cross-sectional height of 4-10 mm. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have a cross-sectional width of 125 mm and a height of cross section 5.2-7 mm. 10. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have a cross-sectional width of 125 mm and a height cross section 6.0 mm. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have fins attached to the flat sides of said tubes, said fins that are 10 mm high and spaced 9 to 12 fins by 2.54 cm (inch). A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have a cross-sectional width of 200 mm and a height of cross section 17-20 mm. 13. A large-scale field-assembled air-cooled industrial steam condenser with all secondary bundles according to claim 1, wherein said tubes (2) have a cross-sectional width of 200 mm and a height cross section of 18.8 mm. 14. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have a cross-sectional width of 125 mm and a height cross section 4-10 mm. A large-scale field-assembled air-cooled industrial steam condenser with all sub-bundles according to claim 1, wherein said tubes (2) have a length of from about 1700 mm to about 2400 mm. A large-scale field-assembled air-cooled industrial steam condenser with all subbundles according to claim 1, comprising from about 40 to about 60 of said tubes (2).