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FIELD OF INVENTION
The present invention relates to a deaerating condenser adaptable in thermal
power plants.
BACKGROUND OF INVENTION
In normal Thermal Power Plant, condensate from the condenser flows through a
Gland Steam Condenser (GSC), Low Pressure Heaters (LPH) and a Deaerator.
Inside the deaerator, the condensate comes in contact with steam and ensure a
thorough mixing of steam and condensate. Deaerators are used to
i) Reduce the dissolved oxygen levels to 0.005 c/liter.
ii) Provide suction head to Boiler Feed Pump
The condensate coming out of the condenser is normally having dissolved
oxygen in the levels of 0.03 c/liter, and passed through the deaereators to
reduce the oxygen level to 0.005 cc/ltr. Spray valves and trays are provided
inside the deaerator to have sufficient contact time between both the fluids. The
condensate leaving out of the deaerator will have 0.005c/litre of oxygen.
Surface condensers are used for condensing steam coming out of steam turbine
and the condensate is recirculated for better efficiency of thermal cycle. These
condensers are also required to control the Dissolved Oxygen (DO) level at
condenser outlet. Normally expected Dissolved Oxygen (DO) level at the outlet of
condensate is 0.03 cc/liter. It is imperative that lower levels of Dissolved Oxygen

(DO) at the condensate outlet should be maintained for protection of boiler
tubes. The problem becomes multi-dimensional when make-up water with rich
Dissolved Oxygen (DO) content is dumped into the condenser.
Conventional condensers use various techniques like venting, higher steam flow
areas, optimum hotwell sizing capacity etc. to control Dissolved Oxygen (DO)
level at outlet of condensate. There is limitation for adopting above conventional
procedures and hence Dissolved Oxygen (DO) levels below 0.03 c/liter are not
normally achieved. Hence, deaerators are used in addition to the condenser to
reduce the DO-level to 0.005 cc/ltr.
OBJECTS OF INVENTION
It is therefore an object of the present invention to propose a deaerating
condenser adaptable in thermal power plants.
Another object of the present invention to propose a deaerating condenser
adaptable in thermal power plants which eliminates the existing deaerator in the
system.
A still another object of the present invention to propose a deaerating condenser
adaptable in thermal power plants which ensure a dissolved oxygen level of
0.005cc/ltre of oxygen in the condensate coming from the condenser.
BRIEF DESCRIPTION OF THE INVENTION
According to the invention, a deaerating condenser is provided which is capable
to reduce the dissolved oxygen (DO) level at the condensate exiting from the
condenser. Thus, the condenser is modified to act as a deaerating condenser and
simultaneously eliminate the existing deaerator.

In order to form a deaerating condenser, out of the existing condenser or to
produce a deaerating condenser per se, the tube layout including the disposition
of the tubes has been modified enabling uniform distribution of steam over the
entire shell area which interalia results in better venting. Further, a two-bank
tray system has been designed and configured. The tray system is disposed
below the tube layout inside the hotwell portion of the condenser. This
arrangement ensures thorough mixing of the falling condensate with the steam
and reduction of partial pressure of the dissolved gasses. Hence the dissolved
gasses in particular the dissolved oxygen is vented through the venting means.
The level of dissolved oxygen in the condensate coming-out of the deaerating
condenser is found to be about 0.005 cc/ltr.

An improved deaerating condenser for a steam turbine capable of deaerating large quantity of makeup water and reducing the dissolved oxygen level (DO- level) at the outlet of the condensate, the improvement tube layout (3) inside the hotwell portion (1) of the condenser is modified to ensure a thorough mixing of the falling condensate (4) with the steam (5) leading to reduction of partial pressure of the dissolved gases; and a two-bank tray arrangement (2) is provided which is removably disposed below the modified tube layout (3) inside the hotwell portion (1) of the condenser which allows restriction of the DO-level at the outlet of the condensate to the range of 0.005 cc/litre, wherein the dissolve gases in particular dissolved oxygen are vented out through the venting means.