Heat exchange – With first fluid holder or collector open to second fluid – Separate external discharge port for each fluid
Reexamination Certificate
2000-04-10
2001-10-02
Flanigan, Allen (Department: 3743)
Heat exchange
With first fluid holder or collector open to second fluid
Separate external discharge port for each fluid
C165S111000
Reexamination Certificate
active
06296049
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a condenser for condensing exhaust steam from a steam turbine used in a thermal power plant or a nuclear power plant.
2. Description of the Related Art
A steam turbine used in a thermal power plant or a nuclear power plant sends the steam worked and expanded therein to a surface condenser. The exhaust steam flowing into this condenser is heat-exchanged with cooling water, such as seawater, river water, etc. in cooling tubes and condensed and collected.
FIG. 7
shows the schematic structure of a conventional condenser. In a condenser shell
1
, two steam cooling tube bundles
2
of the same construction are disposed. Hereinafter, the description is made with respect to only one of steam cooling tube bundles
2
, for the simplicity of the explanation. Steam cooling tube bundle
2
is composed of a number of steam cooling tubes
15
which are disposed in parallel with each other and extend horizontally. Steam cooling tube bundle
2
is divided into an upper tube bundle
2
A and a lower tube bundle
2
B. In a central space
16
formed between upper tube bundle
2
A and lower tube bundle
2
B, an enclosure
3
is disposed, in which an air cooling tube bundle
4
is disposed.
Air cooling tube bundle
4
is composed of a number of air cooling tubes
17
which are disposed in parallel with each other and extend in the extending direction of steam cooling tubes
15
, and cools non-condensable gases, such as Air, Ammonia and the like which are contained in turbine exhaust steam or flow therein from other systems and parts. Further, at the lower part of condenser shell
1
, a hot well
5
is disposed to collect and discharge drain (condensed water) condensed in steam cooling tube bundles
2
and air cooling tube bundles
4
.
The turbine exhaust steam discharged from the steam turbine enters into condenser shell
1
, and flows into steam cooling tube bundle
2
from the outer circumference of steam cooling tube bundle
2
. Then the turbine exhaust steam is condensed on the surfaces of steam cooling tubes
15
, while it flows toward air cooling tube bundle
4
. The drain condensed in steam cooling tube bundle
2
drips into hot well
5
.
The turbine exhaust steam contains Ammonia gas generated through decomposition of a corrosion inhibitor poured in boiler feed water. And therefore, with the condensation of the steam in steam cooling tube bundle
2
, the concentration of Ammonia solved in the drain increases gradually. As partial pressure of steam drops on the surface of air cooling tubes
17
of air cooling tube bundle
4
, steam is further condensed, and as a result, the drain (condensed water) of high Ammonia concentration is generated. The drain of high Ammonia concentration also drips into hot well
5
from air cooling tube bundle
4
.
Further, Copper alloy is generally used for steam cooling tubes
15
of steam cooling tube bundle
2
. This Copper alloy cooling tubes has the nature to be corroded severely with the drain (condensed water) of high Ammonia concentration. This phenomenon is called “Ammonia attack”. Therefore, Titanium which has excellent corrosion resistance is generally used for air cooling tubes
17
of air cool tube bundle
4
.
However, a conventional condenser has such a problem that steam cooling tubes
15
composing lower tube bundle
2
B are corroded by the drain of high Ammonia concentration, because the drain of high Ammonia concentration condensed in air cooling tube bundle
4
drips into hot well
5
while contacting with steam cooling tubes
15
of lower tube bundle
2
B. This kind of problem is also generated in a case where turbine exhaust steam contains corrosive gases other than Ammonia. Further, in many cases, with the progress of the condensation of steam, the corrosion is generated near support plates and tube plates where Ammonia of high concentration tends to be generated.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a condenser that is capable of preventing the corrosion of steam cooling tubes by highly corrosive condensed water.
These and other objects of this invention can be achieved by providing a condenser including, a steam cooling tube bundle having a number of steam cooling tubes disposed in parallel with each other and extending horizontally, an enclosure enclosing a central space formed at a center portion in a vertical direction at an inside of the steam cooling tube bundle, an air cooling tube bundle disposed in the enclosure and having a number of air cooling tubes disposed in parallel with each other and extending along an extending direction of the steam cooling tube bundle, and a tube support plate supporting the steam cooling tube bundle. The steam cooling tube bundle includes an upper tube bundle positioned upward of the central space and a lower tube bundle positioned downward of the central space. The enclosure includes a pair of enclosing bodies disposed separately each other and symmetrically with respect to a vertical surface dividing the steam cooling tube bundle into two parts. Each of the enclosing bodies includes an upper enclosing plate having at least a sloping surface inclined downward to an outside from an inside of the enclosure and a bottom enclosing plate disposed downward of the upper enclosing plate. The bottom enclosing plate includes an outermost end extending outside from an outermost end of the upper enclosing plate, and further includes an outer dam part erected at the outermost end of the bottom enclosing plate. The bottom enclosing plate includes an innermost end extending inside from an innermost end of the upper enclosing plate, and further includes an inner dam part erected at the innermost end of the bottom enclosing plate. A lower end portion of the outermost end of the upper enclosing plate is joined to an upper surface of the bottom enclosing plate, thereby dividing an upper space of the upper enclosing plate into an inner space and an outer space. A flow opening is formed at a joined portion of the upper enclosing plate and the bottom enclosing plate to communicate the inner space and the outer space. And a drain opening is formed at a joined portion of the bottom enclosing plate positioned at the inner space side and the tube support plate.
According to one aspect of this invention, there is provided a condenser including, a steam cooling tube bundle having a number of steam cooling tubes disposed in parallel with each other and extending horizontally, an enclosure enclosing a central space formed at a center portion in a vertical direction at an inside of the steam cooling tube bundle, an air cooling tube bundle disposed in the enclosure and having a number of air cooling tubes disposed in parallel with each other and extending along an extending direction of the steam cooling tube bundle, and a tube support plate supporting the steam cooling tube bundle. The steam cooling tube bundle includes an upper tube bundle positioned upward of the central space and a lower tube bundle positioned downward of the central space. The enclosure includes a pair of enclosing bodies disposed separately each other and symmetrically with respect to a vertical surface dividing the steam cooling tube bundle into two parts. Each of the enclosing bodies includes an upper enclosing plate having at least a sloping surface inclined downward to an outside from an inside of the enclosure and a bottom enclosing plate disposed downward of the upper enclosing plate. The bottom enclosing plate includes an outermost end extending outside from an outermost end of the upper enclosing plate, and further includes an outer dam part erected at the outermost end of the bottom enclosing plate. The bottom enclosing plate includes an innermost end extending inside from an innermost end of the upper enclosing plate, and further includes an inner dam part erected at the innermost end of the bottom enclosing plate. A lower end portion of the outermost end of the upper enclosing plate is joined to an upper surface
Ozeki Toshiaki
Sato Kenji
Shintani Tadafumi
Flanigan Allen
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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