1. Wasting fuel

Scale thermal conductivity is poor, the thermal conductivity of metal than a few dozen times or even nearly a hundred times. After fouling heat transfer surface will make the deterioration of the situation, increase exhaust temperature, reduce boiler thermal efficiency, waste of fuel. According to the determination, the relationship between the scale thickness and the waste of fuel is shown in the table.

2. Affect safe operation

Normal operation of the boiler, the metal heat soon after the heat transfer to the furnace water, the temperature difference between the two is about 30 ~ 100 ℃. When there is scale, the heat of the metal is hard to be transferred to the boiler water because of the scale blockage, so the temperature rises sharply and the strength drops significantly. For example, when a 3 millimeter thick scale is formed in the boiler, the temperature of the steel rises from 280 ° C to 580 ° C and the tensile strength drops from 40 kgf / mm 2 to 10 kgf / mm, causing the hand-pressed part Overheating, blistering, and even rupture.

3. Destroy the water cycle

Boiler after the birth of scale, due to heat transfer is not good, so that evaporation decreased, reducing boiler output. If the water pipe fouling, cross-sectional flow to reduce the increase of water circulation flow resistance, the pipe will be completely blocked, destroying the normal water cycle, resulting in burst pipe accident.

4. Shorten boiler life

Scale attached to the boiler heating surface, especially in the pipe, it is difficult to remove. In order to descaling, it is necessary to shut down the furnace frequently for cleaning. Therefore, the overhauling cost is not only labor-intensive but also material-intensive. Due to the frequent mechanical and chemical descaling, the heat is damaged and the service life of the boiler is shortened.

5. Corrosion boiler metal

Dissolved oxygen and carbon dioxide gas in the water can cause boiler metal corrosion. Corrosion is usually divided into two types of uniform corrosion and local corrosion, mainly localized corrosion. Even corrosion is the role of metal in the corrosive medium, the entire metal surface are subject to corrosion, the degree of reduction of the thickness of the metal is roughly equal. Local corrosion is the corrosion of individual parts of the metal surface, the formation of local pits, the corrosion rate is much faster than the uniform corrosion. Boiler steel is corroded, the thickness of the thinning, stress increases, and even reached the ultimate strength, can not withstand the pressure of the work and the destruction occurred.

6. Pollution steam quality

Steam is contaminated and usually refers to the steam with impurities and moisture to lower its quality. When the boiler water contains more dissolved salts and suspended solids, with the continuous concentration of water, salinity and alkalinity increased again and again, there will be a large number of colloidal particles rose to the evaporation surface, so that when the boiler water evaporation The formation of tiny bubbles are not easy to break, it is difficult to merge with the larger, on the evaporation surface accumulation, the formation of a layer of foam, resulting in furnace foam, froth and cofferdam together, the steam entrained more water, salt And other impurities. These impurities deposit in superheaters, steam pipes, and steam equipment, affecting not only heat transfer, thermal efficiency, but also equipment damage and accidents