Deaerator Function On Utility Units
Utility units are arguably the most important part of any industry. Utility units are responsible for the supply of water, energy, and other essential services that support plant operations. Daerator is one of the equipment in the distillation unit. This article will discuss the deaerator scientifically, detailing its working principles, types, as well as its importance in generating steam that drives an electric generator.
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| Deaerator |
What is a Daeerator?
A deaerator is a device used in
the power generation industry to remove oxygen and other dissolved gases from boiler-feed
water. Boiler feed water is vital in generating the steam needed to drive
turbines and produce electrical energy. The main problem is that this feed
water often contains oxygen which can cause corrosion of the system components.
Daeerators are the solution to this problem.
Critical Role of Daeerator
1. Oxygen Removal
The primary role of the deaerator is to remove oxygen from the boiler feed water. Oxygen in water is a powerful corrosion agent and can damage pipes, tanks, and other components in the power generation system. By removing oxygen, the deaerator helps protect the system infrastructure and extends the life of the equipment.
2. Dissolved Gas Removal
In addition to oxygen, aerators also help remove other dissolved gases, such as nitrogen and carbon dioxide, from the feedwater. The removal of these gases reduces the risk of sediment formation, damage, or corrosion in the power generation system.
3. Improves Efficiency
Daeerators also improve operational efficiency. Water that is already free of oxygen and dissolved gases allows the boiler to produce steam better, which in turn produces more energy from each unit of fuel used.
4. Reduced Chemical Requirements
The use of a deaerator can reduce
the need for precipitating chemicals in the system, ultimately reducing
operational costs and environmental impact.
Working Principle of Daeerator
1. Feed Water Heating
First of all, the cold feed water is heated. This heating helps to reduce the solubility of oxygen in the water. The feed hot water enters the deaerator.
2. Degassing
When water is exposed to air or
certain gases, these gases can be dissolved in water due to certain pressures
and temperatures. When the pressure or temperature changes, or when there is
contact with a larger surface, these dissolved gases can be released from the
water in the form of bubbles or escaping gas. The air trapped in the feed water
is removed from the atmosphere. This process is known as degassing and helps to
remove oxygen and other dissolved gases.
After the degassing process, the
feed water that has been freed from dissolved gases is stored in a storage
tank. It is this water that will be used in the boiler to produce steam.
Typically, the steam generated in
the aeration process is used to heat the cold feedwater before it enters the
boiler. This heating helps maintain the appropriate temperature and reduces the
risk of re-dissolving oxygen in the water.
Types of Deaerators
There are several types of generators
used in the power generation industry:
This is the most common type of deaerator.
The feed water flows through a series of specially arranged trays inside the
daerator. Vertical domed deaeration is installed above the Horizontal vessel.
Boiler feedwater enters the Vertical domed deaeration section above the
perforated trays and flows downward through the trays. Low-pressure deaeration
steam enters the bottom tray and flows upward through the tray. Dissolved gases
contained in the feedwater will escape through vent holes at the top of the
Vertical deaeration.
Feedwater that is pure or does
not contain O2 and other gases will flow into the Horizontal vessel and be
pumped to the Steam Drum for steam generation.
Low-pressure deaeration steam flows in the sparger pipe below the
Horizontal vessel to keep the boiler feedwater at the right temperature.
External insulation of the Horizontal vessel is usually provided to minimize
heat loss.
In a spray daerator, feed water
is sprayed into the chamber under vacuum conditions. This spray maximizes the
contact of water with air for oxygen removal. As shown in Figure, this deaerator has a heating section (E) and
a deaeration process section (F). These two sections are separated by a baffle
(C). Low-pressure deaeration steam enters the vessel through the steam sparger
below the vessel. Feedwater is sprayed into section (E) where it is heated by
the steam rising from the sparger. The purpose of the feedwater spray nozzle
(A) and preheating section is to heat the feedwater to saturation temperature
to facilitate the dissolved gas removal process in the deaeration section.
The preheated feedwater then
flows into the dearation section (F), where it will be deaerated by steam
rising from the sparger system. Contaminant gases will escape through an
opening at the top of the vessel. The deaerated boiler feedwater will be pumped
from the bottom of the vessel to the boiler steam generation system.
This type creates vacuum
conditions inside the deaerator, which helps reduce the evaporation temperature
of the water. This reduces the
risk of oxygen reoxidation.
Conclusion
Deaerators are important devices
in an industry that work scientifically to remove oxygen and dissolved gases
from boiler feed water. The aerator protects system components from corrosion,
improves operational efficiency, and reduces environmental impact. It is a critical hidden component in
keeping operations reliable and efficient, supporting the electricity supply we
rely on every day.