How to Choose A Right Water Treatment That Affects the Safety of Steam Boilers?

November 11, 2020

Using the right water treatment method of the steam boiler can make the boiler water supply hardness qualified. Water supply with unqualified hardness will cause boiler fouling and steam- water together and other boiler malfunctions. In serious situations, it will cause great hidden dangers to boiler safety.

Therefore, it is especially important to choose the right steam boiler water treatment.

There are two common water treatment methods for steam boilers.

1. Ion exchange method.

2. Reverse osmosis purification method.


Next, let us look at the advantages and disadvantages of these two water treatment methods, as well as the supporting situation.


1. Ion exchange method:

Using the principle of ion exchange resin, the water hardness is reduced by combining the anions in the resin with the cations that are easy to scale in the water supply, and the cations are combined with the anions that are easy to generate insoluble substances to generate water.


The chemical reaction formula of ion exchange is as follows:

2NaR   +   Ca2+ (Mg2+) →  CaR2 (MgR2)     +    2Na+

Effective resin     Hard water          Ineffective resin           Soft water


The regeneration process is as follows:

2Na+      CaR2 (MgR2)     →     2NaR               Ca2+ (Mg2+)

Saltwater      Ineffective resin           effective resin      waste liquid discharge



1. The equipment purchase cost is cheap.

2. Low resin price.

3. If the boiler water supply is deep groundwater or tap water, it can be treated effectively.

4. The water quality can reach pH 9 and hardness less than 5.

5. The resin can be replaced at any time and is easy to use.

6. The equipment is light and easy to install.

7. Suitable for most small and medium industrial boilers.


1. Not applicable to large boilers such as power station boilers, CFB boilers, and boilers with special requirements.

2. If the water quality is too bad, it is not recommended to use ion exchange water treatment.


If your water hardness is less than 13mg/L, you can use single-stage softening water treatment equipment, if your water hardness is above this. Two-stage softened water treatment can be used.


2. Reverse osmosis purification method.

Reverse osmosis is a membrane separation technology that uses pressure as the driving force using the function of selective permeable (semi-permeable) membranes. According to the different osmotic pressures of various materials, to achieve the purpose of water treatment.


1. It can remove all the substances in the water except water molecules, completely remove the scale in the water, and the removal rate is 99.99%.

2. Reverse osmosis technology is also one of the main technologies in the use of steam boiler water treatment methods.

3. Widely used in some industrial boilers with extremely strict water quality requirements, such as power station boilers.


1. The price is extremely expensive.

2. High maintenance cost.


If your boiler has an extremely poor water supply. Or the boiler water supply requirement is extremely high, and the reverse osmosis water treatment method can be used.


At present, the most commonly used water treatment method for steam boilers is ion exchange. However, EPCB still recommends to conduct a water quality inspection before choosing a water treatment method, and submit the water quality inspection report to the boiler system supplier, it will help you choose the most suitable boiler water treatment method.


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