How Can I Prevent Hard Scale Buildup in My Industrial Boiler

How Can I Prevent Hard Scale Buildup in My Industrial Boiler


In a steam boiler, hard scale can have a significant impact. There is a direct connection between it and overheating and tube failure in boilers. What causes it? Hard water contains minerals like calcium and magnesium that build up on boiler components.

To maintain a boiler's effectiveness, it is crucial to prevent the accumulation of hard water deposits. Hard scale build-up, even of 1/8 of an inch, can reduce efficiency by up to 25 percent due to heat loss. As a result, boiler room operation costs will increase. Why does hard scale form? What can you do to prevent it?


1) Maintaining regular system monitoring

A boiler's acidity should be monitored to prevent rust and build-up. Occasionally, contaminants are present in the boiler itself, and adjusting the feedwater repeatedly remains the same. Over time, these contaminants are left behind by boiling water and concentrate. Rust and scale are the results.

Monitoring the system regularly allows you to determine when to blow down the system to remove contaminants.

Water in a boiler should have an alkaline pH between 7 and 9. Sodium hydroxide and sodium sulfate salts can be used to maintain this alkaline pH.

You can measure pH from the lower-pressure, cooler side stream of the boiler, which is not possible in the heat of the boiler. Keeping an eye on mineral levels regularly will also prevent rust formation because you will be aware of them and will be in control.

Calcium build-up over time can damage metals and tubes if ignored. It may be impossible to repair these cracks if they become deeper. To avoid the need for replacing tubes and metal, it is essential to be proactive.


2) Water should be treated properly

When water is not appropriately treated, it can oxidize, causing rust on the boiler's tubes. Eventually, these tubes will lose their ability to hold water and will need to be replaced.

It is important to adjust the feedwater so that the dissolved oxygen does not corrode the metal surfaces of the boiler. To eliminate oxygen from the water, you can also use scavenging agents. For scavenging oxygen in your boiler, you can add one of these three chemicals:

  • Hydrazine: Recommended for high-pressure boiler systems
  • Low- and medium-pressure boilers use sodium sulfite
  • In food processing plants, sodium erythorbate is an excellent scavenger that is non-toxic

The pressure of the boiler system significantly influences these oxygen-scavenging agents. For example, a system with a pressure greater than 1000 psi makes sodium sulfite harmful. As a result of the high pressure, the agent transforms into sulfur dioxide or hydrogen sulfide, which are responsible for corrosion. It should only be used in low and medium-pressure boilers, so that's why it's important.

3) Regular boiler maintenance

Routine maintenance is essential to prevent severe damage caused by rust and scale build-up. Maintaining a routine can include preventive measures.

You can begin the chemical treatment program by blowing down the boiler daily. A regular blowdown prevents scale build-up and the accumulation of excess chemicals.


Please find out more about Boiler Solutions' maintenance programs and how our team can help keep your boiler room running smoothly by contacting us today.

Call us at 678-402-5985
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