Boiler is used to produce steam for power generation. The feed water to the boiler has to be treated to protect against scaling and produce high quality steam. Scale is precipitated impurities out of the water and then forms on heat transfer surfaces. This is a problem because scale does not transfer heat very well and causes the boiler tubes to fail by getting too hot. This will reduce the boiler efficiency and damage the boiler.

The water feed to the boiler must not contain any dissolved solids. This type of water is known as demineralized water. Dissolved solids such as hardness and other mineral salts will result in the scaling and deposits in the boiler.

The demineralized water treatment system available to remove the total dissolved solids from water includes :

1. Ion exchange which utilize Cation exchanger, Anion Exchanger, Degasifier, Mixed Bed  Exchanger
2. Reverse Osmosis followed by Mixed Bed Exchanger
3. Reverse Osmosis followed by Electro-deionization

Demineralized water quality for feed to boiler has to be in the range of <0.1 to 0.5 uS/cm depending on the type of boilers.

Source of feed water to produce demineralized water includes, seawater, river water, lake water, well water, service water, industrial water and etc. However, these various feed water sources are not suitable for direct feed to the demineralized water treatment system. Pre-treatment will be required to condition the water before feeding to the demineralized water treatment system.

Different type of pre-treatment shall be applied to different type of feed water. Types of pre-treatment includes :

1. Clarification and sedimentation such as clarifier and chemical precipitation
2. Filtration such as Sand Filtration, Multi-media Filtration, Ultrafiltration

Hitachi Aqua-Tech has the expertise to design, fabricate and commission a complete treatment system to produce demineralized water.

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