Thread Content
1. Boiler steel plates and pipelines are damaged due to overheating. If scale forms inside the boiler, and a certain output (operating pressure and evaporation rate) must be maintained, then the only solution is to increase the temperature on the fire side. Therefore, the thicker the scale, the worse the thermal conductivity, and the higher the temperature on the fire side of the boiler must be. Based on the data obtained from the tests, for a boiler with an operating pressure of 1.4 MPa, the temperature on the fire side ranges from 900 to 1200°C, while the temperature on the water side is 197°C. The temperature of the steel plate in the absence of scale formation is only 215 to 250°C. For boilers of the same type, when there is 0.8–1.0 mm of mixed scale on the boiler plate, the temperature of the steel plate is about 134–160°C higher than when there is no scale present. When 20# steel plate reaches 315°C, its mechanical properties begin to decline, and at 450°C it will creep due to overheating. Therefore, poor water treatment that leads to scale formation in the boiler can easily cause damage to the boiler’s metal. 2. Excessive fuel waste When the boiler is covered with scale, in order to maintain a certain output from the boiler, it is necessary to increase the temperature on the fire side, which in turn increases two types of heat losses: one is the heat loss through radiation to the outside environment ； The first is the heat loss from smoke exhaust. Due to the different operating pressures of the boilers, as well as variations in the thermal conductivity and thickness of the scale, the amount of fuel wasted also varies. In other words, the higher the operating pressure of the boiler, the lower the thermal conductivity of the scale; the greater the thickness of the scale, the more fuel is wasted. Tests have shown that for boilers operating at a pressure of 1.4 MPa, fuel waste can reach 8% due to the formation of 1 mm thick mixed scale. According to statistics, in just the three provinces in the Northeast, coal is wasted in amounts of over 2 million tons per year due to boiler scaling. After chemical descaling, boilers in a certain city achieved coal savings of 5% to 25% on average. 3. Reduced output When scale forms on the boiler’s evaporation surface, heat from the fire side cannot be transferred to the water side quickly, which results in a reduction in the boiler’s output. For example, in a fertilizer plant, poor water treatment led to scaling in the boilers, reducing their evaporation capacity to two-thirds of normal. This resulted in insufficient gas supply, preventing the automated production lines from operating and causing the entire plant to shut down. 4. Increased boiler maintenance requirements When scale forms on boiler plates or pipes, it is very difficult to remove. In particular, the scale can cause problems such as leaks, cracks, damage, deformation, and corrosion in the boiler, which not only damages the boiler itself but also requires a significant amount of labor and resources for maintenance. In this way, not only is the operation cycle shortened, but maintenance costs also increase. In a restaurant in a certain city, due to the lack of water treatment, one boiler had to be replaced every two years, and operations had to be halted for over two months each year. Since the water has been treated using an ion exchange water softening system, the boiler has been operating safely for five years, requiring only routine maintenance checks each year. 5. Threat to safety: Accidents caused by scale account for a significant proportion of boiler accidents, with the figure exceeding 20% in most provinces and cities. This not only causes equipment damage but also poses a threat to personal safety. 6. Increasing the frequency of chemical cleaning damages the boiler, reduces its service life, and creates additional safety hazards. In summary, water treatment for boilers is highly beneficial overall; the costs associated with the infrastructure and operation for water treatment account for only one-fourth of the total savings resulting from such treatment.