Tick, tick, tick…scale and corrosion in a boiler signals bad news. Think equipment damage and repair costs at best and exploding parts and workplace injuries at worst. Ignoring the risks of boiler maintenance is a ticking time bomb for your customers.
Every organisation wants to save time, money and protect the welfare of their employees. Preventing and controlling scale and corrosion in boilers is essential to avoiding unexpected expenditure and nasty accidents. This blog identifies the causes of scale and corrosion and how to cost effectively control the problem.
What causes scale and corrosion in boilers
Scale and corrosion are two different things.
Scale formation is the build-up of hardness salts, such as carbonates and sulphates, as well as a high concentration of silica. Scale accumulates as impurities are precipitated out of the water and settle on the metal, becoming hard and cemented to the boiler.
Corrosion is most commonly the active destruction of the boiler metal, caused by the deep eroding action of dissolved oxygen and carbon dioxide in the boiler water. Dissolved oxygen in untreated feedwater is highly corrosive and can cause pitting very deep in the metal. At this depth, the chemical reaction remains protected and continues until such a time when a failure occurs.
Several types of boiler corrosion can arise including:
- Oxygen attack
- Galvanic corrosion
- Caustic corrosion
- Acidic corrosion
Scale and corrosion can result in:
- Higher maintenance costs
- Higher repair costs
- Down time which affects the production line
- Poor quality of steam which can lessen the quality of the final product
- Increased cost of steam due to low down losses
- Increased running costs
Controlling scale and corrosion in boilers
- Understand what is in the feed water. There will typically be a combination of two types of water that feed into a boiler. There is the fresh water that will come from the plant, and condensed water which is returned from the boiler steam process. Both types of water have their individual which will impact the efficiency of the boiler.
- Understand each boiler’s unique chemistry. General guidelines for the boiler’s individual needs, based on the pressure at which it runs, will be provided by the boiler manufacturer. It is recommended to obtain and refer to these documents when designing a personalised water treatment plan.
- Identify if the boiler is at a higher risk. High-pressure boilers require a higher quality of water with fewer contaminants present. Therefore, the need for a specialised water treatment program to avoid the formation of scale and corrosion is greater than that of low-pressure boilers.
- Best practice water treatment program. Having a strategy that addresses the proper pre-treatment for the feed water, controls the internal chemistry of the boiler and tackles return line corrosion is vital to the prevention and control of scale and corrosion disasters.
Scale and corrosion in boilers is expensive and dangerous
What this blog boils down to is that scale and corrosion is a real concern with the potential to cost your customers unnecessary money and create harmful situations.
Over the last 10 years Chemology has developed an extensive range of products, experience and knowledge to help you navigate boiler scale and corrosion problems.
Chemology’s range of specialist water treatment chemicals for scale and corrosion include:
- Corrosion inhibitors
- Oxygen scavengers
- Steam/ condensate corrosion inhibitors
- Alkalinity builders
View our specialised range of Boiler Water treatments HERE
Image: “corrosão” by Gustavo Veríssimo accessed via Flickr 8/6/18