We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is a Deaerator?

By Rolando Braza
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A deaerator is a mechanical device used in industrial boilers to remove dissolved oxygen gas from the internal water supply. In most cases the actual device is somewhat small, and often works as something of a filter that can trap oxygen gas bubbles as they pass through the feedwater supply on their way to the main boiler chamber. Gas that is not captured can cause rust and degradation of the boiler machine, which can cause a range of problems both in terms of maintenance and efficiency. There are two primary types, namely tray-type and spray-type; both have similar functions, but work slightly differently. Choosing one over the other is usually a question of how much water there is, as well as the overall size and capacity of the boiler.

Even the best deareators can’t usually capture all loose gas, particularly not in large machines. In these cases, using what’s known as a “scavenger” chemical — sodium sulfite, for instance, or a range of organic and natural compounds — can work alongside the device to finish the process. Owners usually also have to keep an eye on the deaerator and check it regularly for service and cleaning in order to keep it in good working order. This can be time consuming, but is usually better than the alternative should it stop functioning properly.

Basic Concept and Core Importance

Many machines and heavy equipment use boilers as a way of producing energy and powering things like motor rotation. They work by heating water and then harnessing the pressure and heat energy produced. Water, of course, is made of hydrogen and oxygen, but as water boils, particularly as it boils for long periods of time, both of these elements tend to dissolve. There is nothing inherently wrong with dissolved oxygen, but it can and often does pose some pretty serious problems for pressurized machinery.

Most of the time, dissolved oxygen presents itself in gas form, and as a gas, it can stick very easily to the interior walls of the machinery where it can cause corrosion. When the gas particles attach to metal they typically form rust, for instance, which over time can both clog the systems and pollute them. Deaerators usually aim to capture and isolate these gas bubbles before they have a chance to interact with the metal and cause harm.

Tray-Type Examples

In a tray-type deaerator, feedwater enters at the top through a distribution pipe. The water cascades down through layers of perforated trays. At the bottom, low-pressure steam is produced, which moves up through the perforated trays. The steam comes into contact with the feedwater and heats it to its saturating temperature, which causes oxygen and other corrosive gases to separate out. The dissolved gases exit through a vent at the top, while the deaerated feedwater falls to the bottom and into a storage tank where it can be removed later by a technician.

Spray-Type Models

Spray-type models work a little bit differently. Rather than dripping the water through trays, these spray the feedwater in a fine mist. In many cases, the spray is introduced first into a preheated section, which raises the temperature to help release oxygen and other gasses. Steam is produced at the bottom, and it rises to meet the heated feedwater and scrub the gasses from it. These gases are released through a vent at the top. A storage tank is positioned underneath the device to receive the processed feedwater.

Completing the Process

Deaeration is one of the best ways to remove oxygen and other corrosive gases, but it may not remove them completely. In such cases, it may be necessary to apply a chemical that is what is known as a “scavenger” of oxygen. Sodium sulfite is the most popular oxygen scavenger; however it can break down into acidic gases at high temperature, and this can actually increase corrosion in certain settings. Steam systems using high pressure should typically use organic oxygen scavengers instead.

Required Care and Maintenance

A deaerator, just like other equipment in a plant, will experience wear and tear and should therefore be regularly checked and maintained. It is a good practice for operators to conduct regular off-line check-ups to keep the device in good running condition. A checklist is often really useful in the performance of routine checks to avoid missing any steps in the maintenance procedure.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.