Corrosion is one of the most common problems in steam systems. It causes premature degradation of equipments and can be responsible for production downtime. In a badly-designed steam system, it spares no kind of equipment: heat exchangers, steam traps, pumps, pump traps, condensate return piping, deaerator, etc. The most prevalent forms of corrosion are caused by O₂ (oxygen) and CO₂ (carbon dioxide) :

1. Oxygen corrosion, also known as ‘pitting’, creates small holes that can eat through a steel pipe in less than two years.


2. Carbon dioxide in steam causes corrosion when it dissolves in the condensate. Condensate pH drops rapidly with increasing concentrations of CO₂. Acidic condensate eats through pipes, causing a characteristic trough at the bottom of pipes. Byproducts of corrosion are then returned to the boiler where they can create iron deposits.

O₂ and CO₂ are called noncondensable gases because, as opposed to water (H₂O), they can’t condense and get eliminated from the steam system with the condensate. On top of accelerating corrosion, noncondensable gases degrade heat transfers by acting as a thermal insulator in heat exchangers.

Mechanical noncondensables eliminator

In a conventional steam system, corrosion is usually controlled by injecting chemicals in the system, such as sulfite for O₂ and a neutralizing amine for CO₂. In a Lalonde Systhermique SCCS^®, noncondensable gases are eliminated mechanically with an exclusive device, throughout the whole steam system. Mechanical elimination of oxygen and carbon dioxide drastically reduces consumption of corrosion-control chemicals. In most of our projects, this decrease exceeds 50%. In many cases, it reaches 95%!