U.S. patent application number 12/581925 was filed with the patent office on 2010-10-21 for turbine exhaust condenser.
This patent application is currently assigned to RESEARCH COTTRELL DRY COOLING, INC.. Invention is credited to Arie M. Nobel.
Application Number | 20100263840 12/581925 |
Document ID | / |
Family ID | 47780522 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100263840 |
Kind Code |
A1 |
Nobel; Arie M. |
October 21, 2010 |
TURBINE EXHAUST CONDENSER
Abstract
An air cooled steam condenser for condensing exhaust steam from
a steam turbine including a steam delivery manifold, first and
second bundles of aligned elongated tubes extending downwardly at
an angle to the axis of the steam delivery manifold, each bundle
containing a plurality of elongated tubes having exterior aluminum
fins, an exterior coating of aluminum and an interior cladding of
stainless steel having a thickness between about 45 and 125
microns, wherein a height measured between the rounded ends of the
tubes is greater than 220 mm or between 220 and 280 mm and the
length of the tubes is greater than 11 m, preferably between 12 and
14 m or greater.
Inventors: |
Nobel; Arie M.; (Lincoln
Park, NJ) |
Correspondence
Address: |
HOWARD & HOWARD ATTORNEYS PLLC
450 West Fourth Street
Royal Oak
MI
48067
US
|
Assignee: |
RESEARCH COTTRELL DRY COOLING,
INC.
Somerville
NJ
|
Family ID: |
47780522 |
Appl. No.: |
12/581925 |
Filed: |
October 20, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61170839 |
Apr 20, 2009 |
|
|
|
Current U.S.
Class: |
165/120 ;
165/152; 60/690 |
Current CPC
Class: |
F28F 2225/04 20130101;
F28F 1/126 20130101; F28F 19/06 20130101; F28B 1/06 20130101; F28F
2245/00 20130101; F28F 21/089 20130101 |
Class at
Publication: |
165/120 ;
165/152; 60/690 |
International
Class: |
F28D 1/047 20060101
F28D001/047 |
Claims
1. An air cooled steam condenser for condensing exhaust steam from
a steam turbine, comprising: a steam delivery manifold delivering
steam from said gas turbine to said condenser; a first bundle of
aligned elongated tubes extending downwardly at an acute angle
relative to an axis of said steam delivery manifold, each elongated
tube having an inlet receiving steam from said steam delivery
manifold; a second bundle of aligned elongated tubes extending
downwardly at an acute angle to said axis of said steam delivery
manifold and at an acute angle to said first bundle of aligned
elongated tubes each having an inlet receiving steam from said
steam delivery manifold, said first and said bundle of aligned
elongated tubes forming a V-shaped assembly; each of said elongated
tubes having opposed generally parallel flat side walls and arcuate
ends, said elongated tubes each having an external coating of
aluminum with serpentine fins bonded to said side walls and an
internal cladding of stainless steel having a thickness of between
50 and 150 microns and a height measured between said arcuate ends
of the tubes of greater than 220 mm; said elongated tubes having an
outlet delivering condensate to a condensate collection manifold:
and a fan located below said first and second bundles of aligned
elongated tubes directing ambient air upwardly onto said first and
second bundles of aligned elongated tubes.
2. The air cooled steam condenser as defined in claim 1, wherein
said elongated tubes have a length greater than 12 meters.
3. The air cooled steam condenser as defined in claim 1, wherein
said elongated tubes have a length between 12 and 14 meters.
4. The air cooled steam condenser as defined in claim 1, wherein
said elongated tubes are formed of carbon steel having an exterior
coating of an aluminum alloy and said fins are formed of aluminum
brazed to said carbon steel core.
5. The air cooled steam condenser as defined in claim 1, wherein
said internal coating of stainless steel of said elongated tubes
has a thickness of 45 to 125 microns.
6. The air cooled steam condenser as defined in claim 1, wherein
said internal coating of stainless steel of said elongated tubes
has a thickness of about 100 microns.
7. The air cooled steam condenser as defined in claim 1, wherein
said elongated tubes are able to withstand a back pressure of 0.1
mm of mercury.
8. The air cooled steam condenser as defined in claim 1, wherein
the height of said elongated tubes is between 220 and 280 mm.
9. The air cooled steam condenser as defined in claim 1, wherein
the height of said elongated tubes is about 270 mm.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 61/170,839, filed Apr. 20, 2009.
FIELD OF THE INVENTION
[0002] This invention relates to an air-cooled steam condenser for
turbines having improved efficiency. More specifically, this
invention relates to turbine exhaust condensers having banks of
aligned elongated tubes receiving steam from the turbine exhaust
and an axial fan or fans directing ambient air over the tube
banks.
BACKGROUND OF THE INVENTION
[0003] Steam turbines, as invented in 1884, extract thermal energy
from pressurized steam and convert the thermal energy into rotary
motion of the turbine shaft. Steam condensing systems are commonly
used in electric power generating plants, solar collectors, fossil
fuel and nuclear reactors generating steam and other steam
generating processes where steam turbines are used.
[0004] The general configuration of an air-cooled steam condenser
for a steam turbine as disclosed, for example, in U.S. Pat. No.
5,305,945 has not changed much in 30 years. The steam condenser
includes a horizontal steam delivery manifold delivering steam from
the exhaust of the steam turbine, a first set of bundles of aligned
elongated tubes having their inlets communicating with the delivery
manifold along its length, a second set of bundles of aligned
elongated tubes also having their inlets communicating with the
delivery manifold along its length, wherein the first and second
sets of bundles of aligned tubes extend downwardly and define a
V-shaped structure with each bundle of tubes having a condensate
collection manifold, and an axial fan located below the V-shaped
structure formed by the bundles of tubes, directing ambient air
upwardly over the first and second sets of bundles of aligned
tubes. Each of the elongated tubes has opposed flat sidewalls and
arcuate or rounded ends, wherein the external surface of the tubes
is coated with aluminum or an aluminum alloy while the
serpentine-shaped aluminum fins are bonded or brazed to the
external surface of the tubes as disclosed in the above-referenced
U.S. Pat. No. 5,305,945.
[0005] As will be understood by a person skilled in this art, the
efficiency of this embodiment of turbine exhaust condensers will
depend primarily upon the "volume" of the condenser tubes,
including the cross-sectional area and the length of the tubes,
which is limited by the strength of the tubes. In a typical
application where the tubes are formed from mild steel claded with
aluminum or an aluminum alloy, the height of the tubes measured
between the peaks of the rounded ends is typically 219 mm and the
maximum length of the tube is between 10 and 11 meters (m).
Further, the prior art turbine exhaust condensers often encounter
imposing limits on the overall efficiency due to increased pressure
drops experienced at low turbine back pressures. Air-cooled steam
condensers tend to accumulate in the tubes some corrosive
non-condensable gases, such as carbon dioxide and air. Such trapped
gases can seriously corrode the inside of the conventional carbon
steel elongated finned tubes. Thus, there has been a long felt need
to improve the efficiency of turbine exhaust condensers,
particularly air-cooled steam condensers comprising sets or bundles
of finned tubes having a lower pressure drop inside the tubes, and
thereby improve the overall efficiency of steam turbines and the
turbine exhaust condenser of this invention.
SUMMARY OF THE INVENTION
[0006] The air cooled steam condenser for condensing exhaust steam
from a steam turbine of this invention may be similar in design to
the prior art air cooled steam condensers described above. That is,
the condenser includes a steam delivery manifold delivering steam
from the steam turbine to the condenser, a first set of bundles of
aligned elongated tubes extending downwardly at an acute angle
relative to the axis of the steam delivery manifold, wherein each
elongated tube has an inlet receiving steam from the steam delivery
manifold, and a second set of bundles of aligned elongated tubes
extending downwardly at an acute angle to the axis of the steam
delivery manifold and at an angle to the first set of bundles of
aligned elongated tubes, each tube having an inlet receiving steam
from the steam delivery manifold, and wherein the first and second
set of bundles of aligned elongated tubes form a downwardly opening
V-shaped structure. Further, each of the elongated tubes has
opposed generally parallel flat sidewalls and arcuate or rounded
ends; wherein each of the elongated tubes has an external cladding
of aluminum or an aluminum alloy with serpentine-shaped fins bonded
to its sidewalls.
[0007] However, the elongated tubes of the air cooled steam
condenser of this invention further includes an internal coating or
cladding of stainless steel material having a thickness of between
50 and 150 microns and the tubes have a length of greater than 11 m
and able to withstand an internal pressure of 0.1 mm of mercury.
Further, as set forth above, the air cooled steam condenser of this
invention includes an axial fan located below the first and second
set of bundles of aligned elongated tubes, directing ambient air
upwardly onto the first and second set of bundles of aligned tubes,
thereby condensing the steam in the tubes.
[0008] The increase in the strength of the condenser tube resulting
from the thin internal cladding of stainless steel permits the use
of tubes of greater height and length resulting in a significant
increase in capacity and cost savings. For example, the height
measured between the rounded or arcuate ends of the tubes may be
increased about 23% from 219 mm to 270 mm and the length of the
tubes may be increased by about 25% from typically 10 to 11 m with
the prior art to greater than 12 m with the present invention.
Thus, the number of tubes may be reduced by as much as 20% for the
same capacity. Further, as will be understood by those skilled in
this art, the lower the back pressure, the greater the efficiency
of the steam turbine. The increased internal cross sectional area
of the tubes allows a lower back pressure of the steam turbine. In
one preferred embodiment, the length of the condenser tubes is
between 12 and 14 m or up to 16 m or greater. The thickness of the
internal cladding of stainless steel in one preferred embodiment is
between 45 and 125 microns or about 100 microns. Further, in one
preferred embodiment, the height of the elongated tubes measured
between the arcuate ends is greater than 220 mm. In another
preferred embodiment, the height of the elongated tubes is between
220 and 280 mm or about 270 mm.
[0009] As will be understood by those skilled in this art, various
modifications may be made to the disclosed embodiment of the air
cooled condenser for condensing exhaust steam from a steam turbine
of this invention within the purview of the appended claims and the
disclosed embodiment is for illustrative purposes only and does not
limit the claims in any way.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a side elevation partially broken away of one
embodiment of an air cooled condenser for condensing exhaust steam
from a steam turbine of this invention;
[0011] FIG. 2 is a perspective view of a bundle of aligned
elongated condenser tubes as may be used with a condenser of this
invention; and
[0012] FIG. 3 is a cross-sectional view of the elongated tubes
shown in FIG. 2.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0013] As set forth above, the air cooled steam condenser of this
invention is particularly, but not exclusively adapted to condense
steam from the exhaust of a steam turbine. A steam turbine is a
mechanical device that extracts thermal energy from pressurized
steam and converts it to rotary shaft motion. Steam turbines have
been used commercially for over 100 years and are particularly
suited to be used to drive an electric power generator. About 80%
of all electricity generated in the world is by use of steam
turbines. Air cooled steam condenser systems are commonly used in
various industries as set forth above. However, there are limits in
the overall efficiency of current turbine exhaust steam condensers
due to the higher pressure drops experienced at low turbine back
pressure. Further, air-cooled steam condensers for condensing steam
from a steam turbine also accumulate corrosive non-condensable
gases, such as carbon dioxide and air. Such trapped gases can
corrode the inside surface of conventional carbon steel finned
tubes as disclosed in the above-referenced patent.
[0014] The embodiment of the condenser 20 as shown in FIG. 1 for
condensing steam from a steam turbine includes a steam delivery
manifold 22, a first set of bundles of aligned elongated condenser
tubes 24 extending downwardly at an acute angle relative to the
axis "a" of the steam inlet manifold 22 and a second set of bundles
of aligned elongated condenser tubes 26 extending at an acute angle
to the axis "a" of the steam inlet manifold 22 and, in this
embodiment, at an acute angle relative to the first set of bundles
of aligned elongated tubes 24. The first and second sets of bundles
of condenser tubes are supported on a tent-shaped or V-shaped frame
structure 28 as shown in FIG. 1. The condenser assembly 20 further
includes a axial fan 30 directing ambient air upwardly onto or
through the first and second sets of bundles of elongated condenser
tubes 24 and 26 as shown by arrows 56. The fan is driven by an
electric motor 34 connected to a motor speed reducer 36, rotating
the blades of the fan 30. The fan blades are partially enclosed
within a fan deck or housing 32 directing ambient air upwardly into
the first and second sets of bundles of elongated condenser tubes
24 and 26 as shown in FIG. 1. The condenser assembly further
includes condensate collection manifolds 38 which receive the
condensed water from the steam received through the delivery
manifold 22. As will be understood by those skilled in this art,
the inlet steam delivery manifold 22 has a plurality of openings
which receive the elongated condenser tubes, ambient air is blown
upwardly onto or through the tubes, condensing the steam in the
tubes and the condensate then flows down the tubes into the
condensate collection manifolds 38 and the condensate is then
recycled through the condensate return manifolds 38 to a boiler
(not shown).
[0015] FIGS. 2 and 3 illustrate one embodiment of the condenser
tubes of the air cooled steam condenser of this invention. FIG. 2
illustrates a portion of a bundle of aligned elongated finned tubes
27. As shown, the bundle of tubes include elongated tubes 40 each
having generally parallel and generally flat sidewalls 42 and
arcuate or rounded end walls 44. In the disclosed embodiment, the
flat sidewalls 42 include "serpentine" shaped fins 46 as shown in
FIG. 2. However, as will be understood by those skilled in the art,
the fins 46 may take other shapes.
[0016] FIG. 3 illustrates one preferred embodiment of a partial
cross-section of the elongated tubes 40, wherein the tubes 40 may
be formed of mild steel, for example, as shown at 48 having a thin
exterior coating of aluminum or an aluminum alloy 50, particularly
where the serpentine-shaped fins 46 are formed of aluminum when
brazed or bonded to the base carbon steel core 48 as described in
the above-referenced patent.
[0017] In the preferred embodiment of the condenser 20 for
condensing steam from the exhaust of a steam turbine of this
invention, the interior surface of the elongated tubes is clad with
a layer of stainless steel as shown at 52 which has several
important and unexpected advantages, including providing increased
strength, permitting a greater cross-sectional area and length of
the tubes, significantly improving the efficiency of the steam
condenser and the steam turbine.
[0018] First, as set forth above, the stainless steel interior
cladding or coating 52 of the tubes 40 significantly increases the
strength of the condenser tubes 40, permitting the use of tubes
having a greater height and internal cross-sectional area, thereby
improving the efficiency of the condenser 20. For example, in a
conventional air cooled steam condenser of this type, the typical
height of the tubes measured between the rounded ends is about 220
mm. However, where the tubes have an interior cladding of stainless
steel, the tubes may have a height of 270 mm or greater. Further,
for an equivalent pressure drop, the length of the tubes may be
increased from typically 10 to 11 m to 12 to 14 meters and up to 14
to 17 m or greater where a larger capacity fan is utilized. The
interior cladding of stainless steel may be relatively thin,
ranging from about 45 to 125 microns or more preferably about 100
microns. As will be understood by those skilled in this art, an
internal cladding of about 100 microns of stainless steel does not
significantly increase the cost of the elongated tubes 40, but as
discovered by the applicant, this internal cladding of stainless
steel results in a significant improvement in the overall strength
of the elongated tubes, resulting in an increase in the internal
cross-section and length of the tubes and thus an increase in
efficiency of the condenser and reduced cost. Further, as set forth
above, the improved air cooled steam condenser for condensing steam
from the exhaust of a steam turbine of this invention also results
in improved efficiency of the steam turbine. As will be understood
by those skilled in this art, the lower the back pressure of the
steam turbine, the greater the efficiency. Thus, because the
condenser tubes have a greater internal cross-section and length,
the turbine exhaust condenser of this invention can condense steam
at a lower back pressure, resulting in an improved efficiency of
the steam turbine.
[0019] As will be understood by those skilled in this art, various
modifications may be made to the air cooled condenser for
condensing steam from a steam turbine of this invention within the
purview of appended claims. The stainless steel internal cladding
52 of the elongated tubes 40 may be any conventional stainless
steel, which also has the advantage of reducing corrosion.
Stainless steel differs from carbon steel by the amount of chromium
present in the alloy. Carbon steel rusts when exposed to air and
moisture. The internal cladding of stainless steel also provides
improved corrosion resistance against the presence of non
condensable corrosive gasses, such as carbon dioxide and air in
water vapor. The exterior aluminum alloy coating 50 may be about 50
microns thick. The width of the tubes measured between the
sidewalls may be about 16 to 20 mm.
[0020] Having described the invention, it is now claimed as
follows.
* * * * *