Guide: The scale types of gas-fired steam boilers can be divided into the following categories according to the chemical composition of Xueyan Thermal Energy, and the scale removal methods chosen by Xueyan Thermal Energy. Interested friends, let us take a look. 1) Carbonate salt scale Carbonate salt scale is more common. This kind of scale mainly appears in the place where the water is not boiling. The color is white and the main component is carbonic acid.

The scale types of gas-fired steam boilers can be divided into the following categories according to the chemical composition of Xueyan Thermal Energy, and the scale removal methods chosen by Xueyan Thermal Energy. Interested friends, let us take a look.

　　1) Carbonate scale

　　 Carbonate scale is more common. This kind of scale mainly appears in the non-boiling water. The color is white. Its main component is calcium carbonate, and it also contains a small amount of magnesium carbonate and magnesium hydroxide.

　　 2) Sulfate scale

　　Sulfuric acid salt scale mainly appears on the heating surface of the boiler with high heat load. The color is yellow-white. Its main components are calcium sulfate, calcium sulfate dihydrate and calcium sulfate dihydrate monohydrate. This scale is hard and dense.

　　 3) Silicate scale

　　 Silicate scale mainly appears in the heated parts of the boiler, such as the water wall. The color is off-white, and its main components are wollastonite, zeolite and a small amount of forsterite. Silicate scale is very hard and has very poor thermal conductivity.

　　Gakken Thermal’s method of removing boiler scale is chemical descaling. There are two types, as shown below:

　　1) Alkaline washing method

　　Scope of application: Better effect on silicate scale.

　　Features: The operation is relatively simple, the cost is low, and the side effects are small. However, it consumes a long time and has a relatively poor descaling effect, and is usually used as a pretreatment method for pickling.

　　 2) Pickling method

　　Scope of application: Better effect on carbonates.

　　Features: Simple operation, can dissolve, loosen and peel off scale, with good descaling effect. But it will cause slight corrosion to the boiler body. Corrosion inhibitors are usually added in the pickling process to prevent or slow down the corrosion of metals.