At what temperature should the blowdown valves be opened to drain the boiler?

The blowdown valves in a boiler system are used to remove sediments and impurities that concentrate in the water due to evaporation. Opening the blowdown valves at an appropriate temperature is important to ensure the safety and efficiency of the system.

The correct answer is 90°C (194°F), which is typically suitable for effective blowdown while maintaining safe conditions. At this temperature, the water is still hot enough to ensure that any solid accumulations are effectively suspended and removed while minimizing the risk of thermal shock to the system. This temperature strikes a balance between sufficient heat to keep contaminants in suspension and avoiding potential reveals of dangerous steam.

Thermal considerations are pivotal when deciding on the blowdown temperature, as opening the valves at significantly lower temperatures might not effectively remove sediment, while too high of a temperature might increase the risk of accidents or equipment damage. Understanding these principles helps ensure the boiler operates safely and efficiently while adhering to best practices in power engineering operations.