Information about boiler feed water

In order to serve the work as well as the operating process of the plant, the use of standard boiler feed water will help improve work efficiency and ensure better production quality. We need to pay attention to 2 main factors when working with boilers of feed water:

pH: When the pH is low, there is a lot of dissolved oxygen, which increases the possibility of electrochemical corrosion and is prone to fire and explosion at dangerous levels.

Water hardness: Water supplied to the boiler reduces the ability to exchange heat and causes a loss of fuel, in case of prolonged use of this water source, it can cause fire and explosion in the furnace.

Therefore, the treatment of boiler feed water is always put on top as well as boiler water supply standards are always paid attention to by operators.

The meaning of water treatment for boilers

Boiler feed water treatment has important purposes such as:

A certain amount of scale is controlled to prevent dirt from accumulating and sticking to the surface of the boiler ductwork.

Highly effective boiler line corrosion control is available.

Control the amount of dissolved oxygen in the water to avoid oxidation conditions that cause serious damage to metal tools.

Boiler water supply standard

Currently, there are many regulations on the use of boiler feed water issued by competent authorities. To achieve the purpose of preventing dirt, scale and pipes from corroding during use, the supply water needs to meet the following standards:

TCVN 7704 - 2007 Vietnam boiler feed water standard.

ASME American boiler feed water standard.

JIS B8223-2006 or standard EN 12 952-12 water supply standard for boilers, steam pipes.

EN 12 953 -13 European community boiler water supply.

Boiler feed water is usually taken from many different sources, mostly in locations near industrial parks such as rivers, streams, wells... Therefore, there is always a high or low concentration of Ca2+ and Mg2+ in the water source. depends on the water availability of that area.

When the content exceeds the allowable standards, it is called hard water and needs to undergo a new treatment stage to be supplied to the boiler.

Boiler water treatment is a task that needs to be done regularly to avoid hard water entering the boiler, which is highly concentrated and precipitates into an insoluble substance that adheres to the boiler's pipe wall, reducing heat transfer efficiency for the boiler. .

Purpose of using boiler feed water to ensure standards:

Help the boiler save fuel more optimally: Less encountering obstacles due to scale, scale, and deposits in the boiler pipeline causing a more favorable heat exchange state, limiting fuel loss.

Better protection of boiler life: The treatment of water in the boiler ensures that the boiler's service life is maintained in accordance with the regulations on average from 15 to 20 years according to the standard TCVN 7704-2007.

In fact, many works operate after a while due to poor water quality, so there is a lot of scale and sludge in the pipeline, leading to clogged or cracked pipes that must be completely replaced.

Boiler feed water treatment process according to Vietnamese standards
Stage 1: Preliminary treatment of input water source
The input water used in the boiler is river water, groundwater or pumped water in the storage tank. In the first treatment station, the water tank is responsible for storing water for the rear water treatment systems. Garbage, pollutants will be chemically treated, precipitated to be completely removed before putting the water source into the transport chain to the next storage tank.

2nd stage of feed water treatment: Treatment of boiler feed water

At this stage, the boiler feed water treatment needs to apply the following treatment stages:

• Treatment by sedimentation method

Water from the intermediate storage tank is pumped directly into the composite filter column to completely remove suspended sediment in the water. At the same time, it is possible to remove dirt thanks to the next layer of activated carbon filter. This step helps to thoroughly remove all organic matter dissolved in water.

• Method of treating boiler feed water by cation exchange

After the water is put into the primary cation exchange column, it will be acidic by positive ions including Mg2+, Ca2+. Na+ is exchanged with R-H with positive ions that will occupy the important position of H in the resin and release H+ ions.

The concentration of positive ions after passing through the primary cation layers is still high, so it will continue to be passed through the secondary cation column to act like the 1st cation column to completely remove impurities.

• Anion exchange water treatment method

After the treatment of cationic water, the process of water exchange by anion based on R-OH resin is continued. Negative ion sources including SO42-, Cl-, HSiO3- will take the place of OHs and generate OH-. Next is the process of OH- combined with H+ separated from primary and secondary cation exchange columns to create water molecules.

The water after leaving the anion exchange column 1 will be brought to the secondary anion exchange column. Then continue to be put into the mixed exchange column, in which the mixed exchange column has a mixture of RH and ROH resins. are mixed together in a fixed ratio to create a reaction to create clean water.

In the tank, the water is passed through a 0.5 µm fine filtration system and through the RO filtration system to completely remove metals and substances that provide clean water for the boiler system.

Thus, we have helped you better understand the safe boiler water supply standards being applied today. At the same time, we also offer a boiler water treatment process that brings high efficiency to users. In case you need more advice on boiler accessories, you can contact Phuc Minh's technical team for support.