What is the purpose of maintaining a minimum steam flow through a superheater?

Maintaining a minimum steam flow through a superheater is crucial, particularly to prevent overheating. When steam flows through the superheater, it absorbs heat to increase its temperature. If the steam flow is too low, there is a risk that the superheater could become excessively hot, leading to thermal damage or failure of the tubes and other components. This overheating can occur because the heat being supplied to the superheater is not being adequately dissipated through the steam flow.

Moreover, sufficient steam flow also helps in distributing heat evenly across the superheater surfaces, thereby reducing the likelihood of localized overheating. By ensuring a steady minimum flow, the temperature can be kept within a safe operating range, which protects the integrity and longevity of the superheater system.

While the other choices touch on relevant concepts in steam system operations, they do not directly address the primary concern of preventing equipment damage due to overheating in the context of superheater operation.