RU2734089C2 - Industrial steam condenser with completely secondary air cooling - Google Patents

Abstract

FIELD: heat exchange.

SUBSTANCE: disclosed is a new design of high-efficiency, on-site industrial steam condensers, in which all of the beams are made as secondary beams, in the form of an A-shaped frame or a V-shape, with pipes oriented at angle of 25–35 degrees to vertical, steam is supplied from below, and condensate is assembled from bundles from below using combined/hybrid collector, which both supplies steam into pipes, and collects condensate from pipes and which is made in such a way that prevents return of condensate down the riser (risers) for steam supply, note here that pipe cross-section dimensions are 125 mm wide with cross-section height of less than 10 mm, ribs 9.25 mm high arranged 9 to 12 ribs per inch (25.4 mm).

EFFECT: disclosed is an industrial steam condenser with completely secondary air cooling.

17 cl, 14 dwg

Description

FIELD OF TECHNOLOGY

[001] The present invention relates to high performance, field-built, air-cooled industrial steam condensers.

TECHNICAL LEVEL DESCRIPTION

[002] The finned flow tube used in most high performance, on-site, air cooled industrial steam condensers (ACC) employs a flattened tube approximately 11 meters long by 200 mm wide (also called “Airway length”) with semicircular leading and trailing edges and an internal height of 18.8 mm (perpendicular to the airway length). The pipe wall thickness is 1.35 mm. Fins are soldered to both flat sides of each pipe. The ribs are usually 18.5 mm high, and spaced 11 ribs one inch (25.4 mm) apart. The rib surface is wavy to improve heat transfer and stiffen the rib. The standard pipe center-to-center is 57.2 mm. The pipes themselves account for approximately one third of the cross-sectional surface area (perpendicular to the direction of the air flow); whereas the ribs account for almost two-thirds of the cross-sectional surface area. There is a small space, 1.5 mm, between the adjacent ends of the ribs. For summer environmental conditions, the maximum steam velocity through the pipes can usually reach 28 m / s and typically 23 to 25 m / s. The combined single A-frame design along with these tubes and fins has been optimized based on pipe length, fin spacing, fin height and shape, and airway length. Finned tubes are assembled into bundles of heat exchangers, usually 39 tubes per bundle of heat exchangers, and 10-14 bundles are arranged in two heat exchangers, installed together in one A-frame for each fan. The fan is usually located under the A-frame, blowing air upward through the bundles. The overall tube and fin design and the air pressure drop across the tube and fin combination have also been optimized to match the air handling capacity of large fans (36 feet (10.97 m) diameter), 200 to 250 hp. ... This optimized arrangement has remained relatively unchanged across many different manufacturers since the introduction of the single row elliptical tube principle over 20 years ago.

[003] The typical A-frame ACC described above includes both 1st stage condenser bundles, or "primary" bundles, and 2nd stage bundles, or "secondary" bundles. Approximately 80% to 90% of the heat exchanger bundles are 1st stage or primary condenser bundles. Steam enters the top of the primary condenser bundles, while condensate and some of the steam exits the bottom. The first stage configuration is thermally efficient; however, does not provide a means for removing non-condensable gases. To remove non-condensable gases through the 1st stage bundles, 10% to 20% of the heat exchanger bundles are designed as 2nd stage bundles or secondary bundles, usually interspersed with primary bundles, which draw in vapors from the lower condensate collector. With this arrangement, vapors and non-condensable gases pass through the 1st stage beams as they are drawn into the bottom of the secondary beam. As the gas mixture passes through the secondary beam, the rest of the vapor condenses, concentrating non-condensable gases. The tops of the secondary beams are attached to a vacuum manifold that removes non-condensable gases from the system.

[004] Changes to the standard ACC of the prior art have been disclosed, such as in US 2015/0204611 and US 2015/0330709. These applications show the same finned tubes, but sharply shortened, and then located in a series of small A-frames, usually five A-frames per fan. Part of the logic is to reduce the vapor pressure drop, which has little effect on overall performance in summer conditions, but more in winter conditions. Another piece of logic is to factory weld the top steam header piping to each of the bundles, and ship them together, thereby saving costly welding work. The net effect of this arrangement, with a factory installed steam header supplied with tube bundles, is to shorten the length of the tube to accommodate the header in a standard high volume shipping container. Because the tubes are shorter and therefore the overall surface area is reduced, the comparative performance relative to a standard single A-frame design of similar dimensions in summer conditions is reduced by about 3%.

DISCLOSURE OF THE INVENTION

[005] The inventions presented herein are 1) a novel tube design for use in heat exchanger systems including, but not limited to, high performance, field-built industrial steam condensers; and 2) a new design for high-performance, field-built, industrial steam condensers for power plants, etc., which significantly increase the heat capacity of ACC and, in some configurations, reduce material consumption. Various aspects and / or embodiments of the inventions are set forth below:

[006] According to various embodiments of the pipe design, the pipes are 2.044 m long, the cross-sectional dimensions of the pipes are 100-200 mm wide, preferably 125 mm wide (airway length) with a cross-sectional height (perpendicular to the airway length) less than 10 mm, preferably 4-10 mm, more preferably 5.0-9 mm, even more preferably 5.2-7 mm and most preferably 6.0 mm in height (also "pipe width outside"), with 9-12 spaced ribs, preferably 8.9 ribs per inch (25.4 mm). According to yet another preferred embodiment, the actual ribs can be 17-20 mm high, preferably 18.5 mm high, and span the space between two adjacent tubes, effectively creating a 9.25 mm rib for each tube on each side.

[007] Making pipes with a smaller cross-section (at the same length of the air path, but much less height) directly contradicts the current opinion in the art that pipes should be made with the largest possible cross-section in order to accommodate large volumes steam, which is produced by a powerful power plant, and the fact that large pipes reduce costs. Although the cost of this device is significantly higher than the prior art pipe design, the inventors unexpectedly found that the efficiency gains with lower pipe heights (in the most preferred embodiment, 30% more efficiency than prior art pipes) is greater than compensation increase in value. This new pipe design can be used in high performance, field-built, prior art industrial steam condensers (eg, as described in the prior art section), or can be used in conjunction with the new ACC design described below.

[008] Turning to a novel design for high-performance, field-built industrial steam condensers, the main feature of the present invention is that all ACC tube bundles of the present invention are constructed as secondary tube bundles while steam is supplied to vertically oriented tubes. (aligned parallel to the transverse axis of the bundle, with each tube, usually oriented at an angle of 25-35 ° and preferably 30 ° to the vertical) from the bottom, and condensate is collected from the tube bundles from the bottom, preferably using a combination / hybrid manifold, which as steam into the pipes, and collects condensate from the pipes. In one embodiment, the combination / hybrid header may be designed to prevent condensate from flowing back down the steam riser (s), and instead is fed into a condensate recovery pipe connected to the combined / hybrid header. In an alternative embodiment, a combined / hybrid header can be constructed such that condensate can flow down the steam risers and be removed from the steam conduit closer to the ground. The tops of the pipes are connected to a separate collector for collecting non-condensable gases. This new "fully secondary" ACC device can be made in the form of an A-frame with two secondary bundles connected at the top, with one collector collecting non-condensable gases from pipes, or with two non-condensing collectors, one at the top of each bundle.

[009] As used herein, the terms "completely secondary" and "non-primary" refer to high-capacity, on-site, industrial air-cooled steam condensers in which all tube bundles receive steam from the bottom and collect condensate at the bottom, and non-condensable gases are fed through top. In comparison, in a high-performance, on-site, industrial air-cooled steam condenser, the primary tube bundles receive steam from the top, feed the condensate down and feed the non-condensable gases down into a separate secondary condenser.

[0010] However, preferably, the ACC according to the invention can be made in a V-shape, in which two exclusively secondary condenser banks are connected at the bottom to a single combined header for steam distribution / condensate collection, with a separate non-condensing collecting header at the top of each beam.

[0011] In a preferred V-shape embodiment, since the vapor header is at the bottom of the bundles, the header inlet at more than one location reduces the header size and provides a slightly longer finned tube length. In combination with the smaller pipe cross-section described herein (200 mm less than 10 mm, preferably 4-10 mm, more preferably 5.0-9 mm, even more preferably 5.2-7 mm, and most preferably 6 .0 mm in height), the system exhibits at least 25-30% improved performance over the standard ACC layout and configuration described above, and the installation can be reduced by a similar amount in horizontal area.

[0012] According to yet another alternative embodiment, the novel ACC structure of the present invention can be used with pipes having dimensions of 100 mm by preferably 4-10 mm, more preferably 5.0-9 mm, even more preferably 5.2-7 mm , and most preferably 6.0 mm in height, with offset ribs.

[0013] In accordance with another embodiment, the novel ACC design of the present invention can be used with pipes with a cross section of 120 mm or up to 200 mm by 5-7 mm with "arrow" ribs, with a spacing of 9.8 fins per inch (25, 4 mm).

[0014] In accordance with yet another embodiment, the novel ACC structure of the present invention can be used with pipes having "louver type" fins that are approximately offset fins and are more easily accessible and easier to manufacture.

[0015] According to the preferred and most preferred embodiments of the present invention, in combination with the most preferred ACC configuration and most preferred pipe sizes, the ACC of the present invention has the following characteristics and dimensions:

• Completely secondary bundles (all pipes receive steam from the bottom, feed condensate through the bottom, and feed non-condensable gases through the top); there are no primary beams;

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

• The outer dimension of the pipe is 4-10 mm (preferably 5-7 mm and most preferably: 6.0 mm) per 100-200 mm (most preferably 125 mm) in cross-section;

• Center-to-center distance between pipes is 20-29 mm (most preferably: 24.5 mm);

• The pipe wall thickness is 0.7-0.9 mm (most preferably 0.8 mm);

• The number of tubes in a bundle is 40-60 (most preferably 50);

• The length of the pipe is 1700-2400 mm (most preferably 2044 mm);

• Lancet fins (preferably, not required) are routed between adjacent pipes and thermally connected to both pipes;

• The rib height is 17-19 mm (most preferably 18.5 mm [effective height 9.25 mm per pipe]);

• The length of the airway fin is 95-195 mm, most preferably 120 mm.

[0016] According to this most preferred embodiment, the total beam surface area compared to the prior art ACC having the same total fan power, steam volume and thermal conditions is 79%. Likewise, the total horizontal 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.

[0017] In addition, the ACC structure of the present invention can be more easily installed in place since it requires less overall space within the power plant.

BRIEF DESCRIPTION OF THE GRAPHIC MATERIALS

[0018] FIG. 1A is a perspective view of a portion of a heat exchanger of a high performance, field-built, industrial air-cooled steam condenser of the prior art.

[0019] FIG. 1B is a partially exploded and enlarged top view of a portion of a heat exchanger of a prior art high performance, field-built industrial air-cooled steam condenser showing the orientation of the tubes relative to the steam distribution header.

[0020] FIG. 2 is a perspective view of a portion of a heat exchanger of a high performance, on-site industrial air cooled steam condenser (“ACC”) in accordance with a first embodiment of the present invention.

[0021] FIG. 3 is a perspective view of a portion of a heat exchanger of a high performance, on-site industrial air cooled steam condenser (“ACC”) in accordance with a second embodiment of the present invention.

[0022] FIG. 4A is a perspective view of a portion of a heat exchanger of a high performance, on-site industrial air-cooled steam condenser (“ACC”) in accordance with a third embodiment of the present invention.

[0023] FIG. 4B is a perspective view of a portion of a heat exchanger of a high performance, on-site industrial air-cooled steam condenser (“ACC”) in accordance with a fourth embodiment of the present invention.

[0024] FIG. 5 is a perspective cross-sectional view of a prior art ACC pipe and fins.

[0025] FIG. 6 is a perspective view of mini-pipes and fins according to one embodiment of the present invention.

[0026] FIG. 7 is a perspective view of mini pipes and fins according to another embodiment of the present invention.

[0027] FIG. 8 is a side view of one line of a high-performance, on-site, industrial air-cooled steam condenser in accordance with an embodiment of the present invention, with a V-arrangement of exclusively secondary pairs of heat exchanger bundles shown in FIG. 4A.

[0028] FIG. 9 is an end view of the high performance, field-built, air-cooled industrial steam condenser shown in FIG. 8.

[0029] FIG. 10 is a top plan view of the high performance, field-built, air-cooled industrial steam condenser shown in FIG. 8, which shows one turbine outlet divided into 6 longitudinal steam columns (6 lines) with 6 cells each.

[0030] FIG. 11 is a perspective view of a secondary finned tubular condenser bundle according to one embodiment of the present invention.

[0031] FIG. 12 is a photographic perspective view of a secondary finned tubular condenser bundle reproducing the drawing of FIG. eleven.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Full A-frame ACC with secondary beams

[0033] As shown in FIG. 2, the tubes 2 are located in the secondary bundles 4. The longitudinal axes of the tubes 2 are aligned parallel to the transverse axis of the tube bundle, with each tube generally oriented at an angle of 25-35 °, and preferably 30 ° to the vertical. Combined headers 6 for distributing steam / condensate are bonded at the bottom of each of the two secondary bundles 4, which are connected at the top in an A-frame. The steam is distributed through the pipes 2 through the combined steam distribution / condensate collection headers 6, and condensate is formed in the pipes 2 when the steam condenses and flows down the pipes 2 to the combined steam distribution / condensate collection header 6. A single non-condensing collecting header 8 is attached to the top of both bundles 6 for collecting non-condensable gases that enter the top of the pipes 2. Steam is fed to a combined collector 6 for distributing steam / collecting condensate from steam line 10 through risers 12. Condensed water that is collected in the combined collector 6 for distribution of steam / collection of condensate, is output from the ACC to the pipe 14 for extracting condensate.

[0034] FIG. 3 shows an embodiment close to that of FIG. 2, except that each bundle 4 is attached at the top to a special non-condensing collecting manifold.

[0035] Full V-Frame ACC with Secondary Beams

[0036] As shown in FIG. 4A and 4B, tubes 2 are located in secondary bundles 4. The longitudinal axes of tubes 2 are aligned parallel to the transverse axis of the tube bundle, with each tube generally oriented at an angle of 25-35 °, and preferably 30 ° to the vertical. A combined steam distribution / condensate collector 6 is attached at the bottom of two secondary bundles 4, which are connected in a V-shape at an angle of 55-65 °, preferably 60 °. Steam is distributed through pipes 2 through a combined steam distribution / condensate collection header 6, and condensate is formed in pipes 2 when the steam condenses and flows down through pipes 2 to a combined steam distribution / condensate collection header 6. Non-condensing collecting header 8 is attached to the top of both bundles 6 to collect non-condensable gases that enter the top of the pipes 2. Steam is fed to the combined collector 6 for distributing steam / collecting condensate from the steam line 10 through the risers 12. The condensed water that is collected in a combined collector 6 for steam distribution / condensate collection, is carried away from the ACC to the condensate extraction pipe 14.

[0037] The new ACC design described above can be used with any known pipe, including the pipes shown in FIG. 5 having a length of about 11 m and a width (or "air flow length") of 200 mm with semicircular leading and trailing edges, and having an internal height (perpendicular to the length of the air path) of 18.8 mm, and a pipe wall thickness of 1.35 mm, with ribs soldered to both flat sides of each pipe, typically 18.5 mm high, with a spacing of 11 ribs per inch (25.4 mm). However, according to a more preferred embodiment, the new ACC structure according to the present invention has the following characteristics and dimensions:

• Completely secondary bundles (all pipes receive steam from the bottom, feed condensate through the bottom, and feed non-condensable gases through the top); there are no primary beams;

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

• The outer dimension of the pipe is 4-10 mm (preferably 5-7 mm and most preferably: 6.0 mm) per 100-200 mm (most preferably 125 mm) in cross-section;

• Center-to-center distance between pipes is 20-29 mm (most preferably: 24.5 mm);

• Pipe wall thickness 0.7-0.9 mm (most preferably 0.8 mm);

• The number of tubes in a bundle is 40-60 (most preferably 50);

• The length of the pipe is 1700-2400 mm (most preferably 2044 mm);

• Lancet fins (preferably, not required) are routed between adjacent pipes and thermally connected to both pipes;

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

• The length of the airway fin is 95-195 mm, most preferably 120 mm. According to this preferred embodiment, a performance increase of 25-30% is achieved over the prior art A-frame design with standard tubes, for one cell at a constant fan power.

[0038] FIG. 8-10 illustrate a typical high-performance, field-built, industrial air-cooled steam condenser in accordance with an embodiment of the present invention, with a V-arrangement of exclusively secondary pairs of heat exchanger bundles shown in FIG. 4A. The device shown in FIG. 8-10 is a 36-cell ACC (6 trunks of 6 cells), with five beam pairs per cell being the most preferred embodiment, but the invention can be used with any ACC size and any number of beam pairs per cell.

Claims (20)

1. High performance, on-site industrial air-cooled steam condenser with fully secondary bundles connected to an industrial plant producing steam containing: two bundles, each of which contains a plurality of ribbed flattened tubes installed next to each other, and these bundles are oriented in such a way that the longitudinal axis of said ribbed flattened tubes is located at an angle of 55-65 ° to the horizontal; a combined collector for distributing steam and collecting condensate, attached to the bottom of each of said bundles and passing along the length of said bundles, configured to both supply steam to the lower part of said pipes and collect condensate generated in said pipe from said steam as cooling; non-condensing collecting header attached to the top of each of said beams and extending along the length of said beams parallel to said header for distributing steam and configured to collect non-condensable gases from said steam. 2. A high-performance, on-site industrial air-cooled steam condenser entirely with secondary bundles according to claim 1, characterized in that all condensate collected from said pipes is collected in said combined steam distribution and condensate collection header. 3. The high performance, on-site industrial air-cooled steam condenser entirely with secondary bundles according to claim 1, characterized in that all the steam supplied to said pipes is supplied from said combined steam distribution and condensate collection header. 4. The high-performance, on-site industrial air-cooled steam condenser completely with secondary bundles according to claim 1, characterized in that the longitudinal axis of said ribbed flattened tubes is located at an angle of 60 ° to the horizontal. 5. The high performance, on-site industrial air-cooled steam condenser with fully secondary bundles according to claim 1, characterized in that it does not contain primary condenser tubes. 6. A high-performance, field-built, industrial air-cooled steam condenser entirely with secondary bundles according to claim 1, characterized in that said two bundles are arranged in the form of an A-frame with a single non-condensing prefabricated header attached to the tops of both said bundles, and with a separate combined manifold for steam distribution and condensate collection connected to the bottoms of both of said two bundles. 7. A high-performance, field-built industrial air-cooled steam condenser entirely with secondary bundles according to claim 1, characterized in that said two bundles are arranged in the form of an A-frame, with two non-condensing collecting headers, each of which is attached to the top one of said two beams, and with two combined collectors for steam distribution and condensate collection, each of which is attached to the bottom of one of the two beams. 8. A high-performance, on-site industrial air-cooled steam condenser entirely with secondary bundles according to claim 1, characterized in that said two bundles are arranged in a V-shape, with a single combined manifold for steam distribution and condensate collection connected to the lower parts of both of said two bundles, and with two separate non-condensing collecting headers, one attached to the top of each of said two bundles. 9. The high-performance, on-site industrial air-cooled steam condenser completely with secondary bundles according to claim 1, characterized in that said pipes have a cross-section width of 100-200 mm and a cross-section height of 4-10 mm. 10. The high-performance, on-site industrial air-cooled steam condenser completely with secondary bundles according to claim 1, characterized in that said pipes have a cross-sectional width of 125 mm and a cross-section height of 5.2-7 mm. 11. The high performance, on-site industrial air-cooled steam condenser with fully secondary bundles according to claim 1, characterized in that said pipes have a cross-sectional width of 125 mm and a cross-section height of 6.0 mm. 12. A high-performance, on-site industrial air-cooled steam condenser with fully secondary bundles according to claim 1, characterized in that said pipes have ribs attached to the flat sides of said pipes, said ribs having a height of 10 mm with an array of 9 to 12 ribs per inch (25.4 mm). 13. The high-performance, on-site industrial air-cooled steam condenser completely with secondary bundles according to claim 1, characterized in that said pipes have a cross-section width of 200 mm and a cross-section height of 17-20 mm. 14. The high performance, on-site industrial air-cooled steam condenser completely with secondary bundles according to claim 1, characterized in that said pipes have a cross-section width of 200 mm and a cross-section height of 18.8 mm. 15. The high performance, on-site industrial air-cooled steam condenser completely with secondary bundles according to claim 1, characterized in that said pipes have a cross-sectional width of 125 mm and a cross-section height of 4-10 mm. 16. The high performance, on-site industrial air-cooled steam condenser with fully secondary bundles according to claim 1, characterized in that said pipes are from about 1700 mm to about 2400 mm in length. 17. The high performance, on-site industrial air-cooled steam condenser with fully secondary bundles of claim 1, comprising from about 40 to about 60 said tubes.

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