DEAERATOR

122, Cheoyongsaneop 3-gil, Cheongnyang-myeon, Ulju-gun, Ulsan, 689-892, Korea

TEL : +82-52-237-2213 FAX : + 82-52-237-2235

E-mail : main@powerhx.com Website : http://www.powerhx.com

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www.powerhx.com

DEAERATOR

General Principle of deaerating[ Typical Deaerator Connections and Accessories ]

Classification by Shape

The removal of dissolved gases from boiler feedwater

is an essential process in a steam system. The presence

of dissolved oxygen in feedwater causes rapid localized

corrosion in boiler tubes. Carbon dioxide will dissolve in

water, resulting in low pH levels and the production of

corrosive carbonic acid. Low pH levels in feedwater cause

severe acid attack throughout the boiler system. While

dissolved gases and low pH levels in the feedwater can be

controlled or removed by the addition of chemicals, it is

more economical and thermally efficient to remove these

gases mechanically. This mechanical process is known

as deaeration and will increase the life of a steam system

dramatically.

Deaeration is based on two scientific principles. The first

principle can be described by Henry’s Law. Henry’s Law

asserts that gas solubility in a solution decreases as the

gas partial pressure above the solution decreases. The

second scientific principle that governs deaeration is the

relationship between gas solubility and temperature.

Briefly explained, gas solubility in a solution decreases

as the temperature of the solution rises and approaches

saturation temperature. A deaerator utilizes both of these

natural processes to remove dissolved oxygen, carbon

dioxide and other non-condensible gases from boiler

feedwater.

The feedwater is sprayed in thin films into a steam

atmosphere allowing it to become quickly heated to

saturation. Spraying feedwater in thin films increases

the surface area of the liquid in contact with the steam,

which results in more rapid oxygen removal and lower gas

concentrations. This process reduces the solubility of all

dissolved gases and removes them from the feedwater.

The liberated gases are then vented from the deaerator.

This system reduces dissolved oxygen concentration to less

than 0.005 cc/liter (7 ppb) and completely eliminates the

carbon dioxide concentration.

Ⓐ Water(Condensate) inlet

Ⓑ Spray Valve

Ⓒ Vent Orifice

Ⓓ Vent Nozzle

Ⓔ Relief Valve

Ⓕ Tray Box

Ⓖ Pressure Gauge

Ⓗ Level Gauge

Ⓘ Man Hole

Ⓙ Drain Nozzle

Ⓚ Tank Saddle

Ⓛ Water Outlet

Ⓜ Sparger Pipe

Ⓝ Deaerator Saddle

Ⓞ Downcomer

Ⓟ Equalizer

Ⓠ OverFlow Nozzle

Ⓡ Steam Inlet

Dissolved oxygen and carbon dioxide in the Boiler Feed

Water of industrial steam generators that are used in

electricity plants and incineration plants, causes the

corrosion of the Boiler Feed Water Container, which

significantly affects the durability of pipes and all the

equipment. To eliminate the dissolved oxygen and carbon

dioxide, installing a deaerator is essential. This deaerator

can also preheat the Boiler Feed Water up to the necessary

temperature as a Feed Water Heater, which helps increase

the efficiency of the equipment.

Generally, the Deaerator is divided into two parts; the top,

deaerating Heater (for degassing) and the bottom, Storage

Section. Due to their different shapes, the deaerating

Heater is classified into Vertical deaerator type, and

Horizontal deaerator type.

Storage Tank

Storage Tank

Storage Tank

Storage Tank

>> Vertical deaerator with horizontal storage tank - Applicable to small and medium capacity(up to 220 ton/hr)

Undeaerated Water Non-Condensibles(Vented)

SteamDeaerated Water

[ O2 concentration in saturated demi-water ]

Dis

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m)

Water Temperature (in Deg C)

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A thermal power station is a power plant in which

heat energy is converted to electric power. The turbine

is steam-driven. Water is heated, turns into steam

and spins a steam turbine which drives an electrical

generator. After it passes through the turbine, the steam

is condensed in a condenser and recycled to where it was

heated; The greatest variation in the design of thermal

power stations is due to the different heat sources, fossil

fuel dominates here, although nuclear heat energy and

solar heat energy are also used. Some prefer to use the

term energy center because such facilities convert forms

of heat energy into electrical energy. Certain thermal

power plants also are designed to produce heat energy

for industrial purposes of district heating, or desalination

of water, in addition to generating electrical power.

[ Large Spray Valve Performance Curve ]

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△P Pressure difference

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Valve N/Z flow Velocity

Ex) flow rate 50t/h flow velocity 8.4m/s valve lift 5.9mm △P 3.7mAg

Va

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Valve lift

Inlet FlowRate(t/h)

>> Horizontal deaerator with horizontal storage tank - Applicable to large capacity (over 220 ton/hr)

Enclosure wall

[ Structure of spray nozzle, collecting (water) and distributing tub and tray ]

[ Power plant process diagram ]