Question 159Steam Plants - 1st Asst/Chief

The correct answer is A) Fouled screen tubes. A high superheater outlet temperature is typically caused by a restriction in the flow of the superheated steam. Fouled or plugged screen tubes can restrict the flow of the hot exhaust gases through the superheater, causing the superheater outlet temperature to rise. This is because the restricted gas flow reduces the heat transfer from the exhaust gases to the superheater tubes. The other options are incorrect because high feed water temperature and dirty or plugged superheater tubes would not directly cause a high superheater outlet temperature. They may contribute to other boiler issues, but a high superheater outlet temperature is most likely due to a restriction in the gas flow, such as fouled screen tubes.