Question 176Steam Plants - Assistant Engineer

The correct answer is C) low superheater outlet temperature because of the insulating effect of soot. The explanation is as follows: A heavy accumulation of soot on the fireside of the superheater acts as an insulating layer, reducing the heat transfer from the hot flue gases to the steam flowing through the superheater. This insulating effect caused by the soot buildup results in a lower superheater outlet temperature, as less heat is being transferred to the steam. The other options are incorrect because: A) high superheater outlet temperature due to gas laning is not the result of soot buildup, B) high superheater outlet temperature due to reduced steam flow is not the direct effect of soot buildup, and D) high superheater inlet temperature due to decreased heat transfer is the opposite of the correct effect.