The distribution pipe that injects feedwater inside a boiler is arranged to reduce what?

The correct choice highlights the importance of managing thermal dynamics within a boiler system. The distribution pipe's design minimizes the likelihood of thermal shock, which can occur when cold feedwater is injected into a hot boiler drum. Such a drastic temperature difference can lead to structural stress and damage to the boiler materials, potentially causing cracks or other failures.

By strategically routing the feedwater, the system can ensure that the water enters the boiler more evenly, allowing the temperature to stabilize and preventing sudden changes that could compromise the integrity of the unit. This careful approach helps maintain the longevity and safe operation of the boiler, ultimately leading to improved efficiency and reliability.

In contrast, other factors such as pressure drops, corrosion, or water quality issues, while significant in their own right, are not directly addressed by the arrangement of the distribution pipe with respect to thermal shock. The focus on thermal shock emphasizes the critical balance needed in boiler operation to protect against temperature-related stresses.