Which of these is not an internal component of a steam drum?

The intermittent blow off line is not considered an internal component of a steam drum. Instead, it serves as an external connection to the steam drum, designed primarily for the purpose of removing accumulated sludge and impurities from the drum. This helps maintain the quality of water within the drum and prevents operational issues that could arise from sediment buildup.

In contrast, components such as the chemical feed pipe, chevron dryer, and baffle are integral to the internal functioning of a steam drum. The chemical feed pipe allows for the introduction of water treatment chemicals directly into the drum, ensuring that the water remains suitable for efficient steam generation. The chevron dryer plays a crucial role in reducing moisture content in the steam before it exits the drum, ensuring that high-quality steam is delivered to the system. Baffles are designed to promote proper water and steam separation within the drum, enhancing the overall efficiency of the steam generation process.

These internal components are vital for the drum’s operation, while the intermittent blow off line facilitates maintenance and operational hygiene, distinguishing it from the other choices that are embedded within the drum's structure and functionality.