What protects super heaters in a boiler?

Super heaters in a boiler are designed to heat the steam generated by the boiler to a higher temperature before it is sent to the turbine. This process increases the efficiency of the power cycle and protects the boiler system from potential damage caused by high temperature and pressure.

Water screen tubes serve a critical role in this context. They are positioned around the super heater and circulate water, which absorbs heat and converts it to steam. This water not only contributes to heating the steam but also acts as a protective barrier that helps to prevent overheating of the super heater elements. By maintaining the temperature of the super heater within safe operational limits, water screen tubes minimize the risk of structural failure or damage due to temperature fluctuations.

While insulation materials, steel plates, and refractory materials may also contribute to various protective functions within a boiler system, they do not specifically address the unique challenges presented by super heaters. Insulation reduces heat loss, steel plates may serve structural purposes, and refractory materials can withstand high temperatures. However, none of these options provide the direct cooling and protection against excessive heat that water screen tubes offer, making them the key protective feature for super heaters in boilers.