Why is feed water treated chemically before entering the boiler drum?

Feed water is treated chemically before entering the boiler drum primarily to change scale-forming salts into a non-adhering sludge. This treatment is crucial because the presence of scale-forming substances, such as calcium and magnesium salts, can lead to the formation of scale on the internal surfaces of the boiler. Scaling can significantly reduce the efficiency of heat transfer within the boiler and, in severe cases, cause overheating and damage to the boiler materials. By converting these salts into non-adhering sludge, the potential for scale buildup is minimized, allowing for smoother operations and enhanced boiler longevity.

The other options address aspects of water treatment but do not align with the primary reason for chemical treatment. Improving clarity is more related to the visual aspect of water rather than its impact on boiler operation. Increasing the water temperature and reducing pressure are operational parameters rather than objectives of feed water treatment. Thus, the focus on chemical treatment being aimed at managing scale formation is what makes it essential for efficient boiler operation.