Industrial gas boilers have a long service life, generally 10-20 years, but to achieve such a long service life and good operating results, maintenance and repair processing is essential. Among them, water treatment is an important step.
The influent of industrial gas boilers must ensure good purity. This is mainly to prevent the boiler from generating scale under long-term high-pressure and high-temperature operation.
The purpose of gas boiler water treatment is to remove the calcium and magnesium ions which are easy to scale in the boiler, reduce the degree of boiler fouling, ensure the heat exchange effect of the boiler, and improve the thermal efficiency.
The process of water treatment is as follows:
1. Pretreatment
When the raw water of the gas boiler is surface water, the purpose of the pretreatment is to remove suspended solids, colloids and organic matter in the water. Usually, a coagulant (such as aluminum sulfate) is added to the raw water to make the above-mentioned impurities aggregate into large particles, sink by their own weight, and then filter into clean water. When groundwater or urban water is used as make-up water, the pretreatment of raw water can be omitted and only filtered. Commonly used clarification equipments include pulsed, hydraulically accelerated and mechanically agitated clarifiers; filtration equipment includes siphon filters, valveless filters, and single-flow or dual-flow mechanical filters. In order to further remove organic matter from the natural gas boiler water, an activated carbon filter may be added.
2. Soften
Gas boilers use natural or artificial ion exchangers to convert calcium and magnesium hard salts into hard-free salts to prevent calcium and magnesium hard scale from forming on the inner wall of boiler tubes.
Water containing calcium and magnesium bicarbonate and having a high alkalinity can also be solved by sodium hydrogen ion exchange or by pretreatment (such as lime addition).
For some industrial boilers, such treatment is usually sufficient, although the salinity of the feed water does not necessarily decrease significantly.
3. Desalting
With the continuous improvement of gas boiler parameters and the emergence of DC boilers, it is even required to remove all salt in the boiler feed water. At this time, it is necessary to use a method of desalting.
