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.
Machinery

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.

What is a Recovery Boiler?

By Kirsten C. Tynan
Updated: May 17, 2024
Views: 8,443
Share

A recovery boiler is a power plant subsystem used to capture energy that would otherwise be lost in waste products that were not completely combusted. This energy is recycled to the primary energy generating system to produce more power. For this reason, this equipment may alternatively be referred to as a heat recovery boiler or as a waste heat recovery boiler. The main requirement for its use is that the system’s waste products have sufficient recoverable energy to drive the primary power generating equipment. Recovery boilers may be used in the power systems for a variety of industrial equipment.

Waste recovered for further combustion in a recovery boiler is usually a gas, a liquid, or a combination of the two. Processes generating these types of wastes include metal refineries, petrochemical processing plants, and other industrial plants operating at high temperatures. Solid material may also be used, though this is less common. The most notable example of solids used in recovery boilers is in papermaking.

Recovery boilers in pulp or paper mills most commonly extract additional energy from a recycled byproduct of the papermaking process known as black liquor. When breaking down wood to make pulp, a chemical compound called cellulose is separated out from other compounds for use in paper. Black liquor is the term for a combination of water and residue left behind from the pulping process. This residue includes not only wood byproducts, but also chemicals used in the extraction process. The mixture is typically concentrated in an evaporator and is then passed on to the recovery boiler for combustion.

Whether black liquor, exhaust gas, or some other waste product is recycled, the waste product is burned in the combustion chamber of a recovery boiler. Heat produced by this combustion is typically used to heat water to create steam. The steam drives equipment, such as a turbine, thereby transforming waste heat into mechanical energy. In turn, the turbine converts mechanical energy into electrical power, which can then be used to operate the facility.

By using a recovery boiler to recapture energy that would otherwise be wasted, an industrial facility can increase its energy efficiency. Fuel cost savings can be dramatic, particularly for systems with high-temperature exhaust. In such systems, as much as half the energy put into the system could be venting up the stack if not recycled. Another benefit of recovery boilers is that the reduction in fuel burned results in reduced greenhouse gas emissions and less impact on the environment.

Share
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
Share
https://www.aboutmechanics.com/what-is-a-recovery-boiler.htm
Copy this link
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.