SUEZ Water - Water Technologies & Water

Feedwater Treatment Chemicals

Reduce corrosion, oxygen-related failures and maintenance costs with SUEZ’s suite of oxygen scavengers

Even when properly treated by a deaerator, boiler feedwater typically contains traces of oxygen that present a risk of corrosion to the feedwater and boiler metallurgy. Oxygen pitting attacks can result in rapid failures in feedwater lines, especially economizers, as well as boilers and condensate lines. An efficient oxygen scavenger treatment program is essential to meet industrial standards and minimize unplanned downtime, production losses and maintenance costs.

Product Highlight

Oxygen scavengers for boiler feedwater treatment

SUEZ’s oxygen scavengers for boiler feedwater include several inorganic and organic oxygen scavengers that can cover all your boiler feedwater requirements.

CorTrol IS Series

The CorTrol IS Series of products are inorganic oxygen scavengers with a common sulfite-based chemistry. Sulfite (SO3) is the fastest oxygen scavenger, especially when combined with a catalyst. It is suitable for steam generation applications operating below 900 psig (62 barg). CorTrol IS products are available in powder and liquid forms to best suit your application’s needs.

CorTrol OS Series

The CorTrol OS Series of products are organic oxygen scavengers that regroup multiple chemistries such as DEHA, Carbohydrazide and others. Organic oxygen scavengers are suited for high pressure (above 900 psig/62 barg) and high purity steam generation applications that are required to limit their intake of total dissolved solids (TDS).

Features & Benefits

Benefits of treating boiler feedwater with oxygen scavengers

Treating your boiler feedwater with SUEZ’s suite of oxygen scavengers goes a long way in preventing rapid failures of the feedwater system and costly downtime of steam generation equipment. The benefits of treating your boiler feedwater include:

  • Controls dissolved oxygen pitting in boiler feedwater, boiler and steam condensate systems
  • Extends equipment life and reliability
  • Reduces maintenance costs associated with dissolved oxygen and equipment failures
  • Minimizes feedwater and condensate iron and copper levels, reducing loading of scale-forming corrosion products to the boiler
  • Reduces boiler system chemical treatment costs

Case Studies

FAQs

What is a boiler feedwater treatment system?

A boiler feedwater treatment system is comprised of a mechanical deaeration step and a chemical deaeration step. Depending on its design, the mechanical deaeration can produce water with dissolved oxygen anywhere from 7 to 3000 ppb as O2. The chemical deaeration step is designed to neutralize the risk of this oxygen residual, reducing as close to zero as possible.

How does a boiler feedwater system (mechanical deaerator) work?

Mechanical deaeration relies on the tendency for gases to have reduced solubility in water at a higher temperature and for individual gases to seek equilibrium and distribute evenly in a given space. Thermal deaerators increase temperatures of the water to drive oxygen out of the water. Pressure deaerators inject steam to create a hot and oxygen-free environment, where the dissolved oxygen will want to transfer more readily. Vacuum deaerators rely only on the second principle of an oxygen-free space, without the help of higher temperatures. Each design has pros and cons and presents different levels of performance.

What are oxygen scavengers for boiler feedwater?

Oxygen scavengers are added to the boiler feedwater to remove trace oxygen, usually following a mechanical deaeration process. Various chemistries can be used as oxygen scavengers, and they will present different benefits. For low-pressure boilers (<900 psig or 62 barg), sulfite-based treatments are standard as they are fast-acting, convenient and economical. For high-pressure boilers (>900 psig or 62 barg), organic oxygen scavengers must be used to prevent sulfur contamination of the steam. In all cases, operating factors must be considered to ensure proper deoxygenation and system protection, such as pH, temperature and contact time.

What is the purpose of feeding oxygen scavengers to boiler systems?

Even following a high-performing mechanical deaeration process, trace oxygen can remain that will present a risk to the feedwater, boiler and condensate systems. Oxygen attack will most often be observed in the economizer section of the feedwater system, as oxygen corrosivity increases proportionally with temperature. An economizer leak can occur within hours of an oxygen contamination and lead to a complete shutdown of the boiler. Adequate treatment using an oxygen scavenger can prevent these costly incidents and offer peace of mind in the event of a deaerator upset.