Question 158Steam Plants - 1st Asst/Chief70% to pass
Dirty generating tube surfaces may cause higher than normal superheater outlet temperatures because _______________.
AI Explanation
The correct answer is A) the boiler must be over-fired to maintain the required rate of steam generation.
Explanation:
Dirty generating tube surfaces reduce the heat transfer efficiency of the boiler, so more heat input is required to maintain the same steam generation rate. To achieve this, the boiler must be over-fired, leading to higher than normal superheater outlet temperatures. The other options are incorrect because they do not accurately describe the effect of dirty generating tubes on superheater temperatures.
Related Questions
#156 Insufficient combustion air supply to the furnace would cause _______________.#157 Under normal operating conditions, a drop in the steam temperature leaving an uncontrolled interdeck superheater could be caused by a _______________.#159 While steaming underway the second engineer reports a high superheater outlet temperature. Which of the following could be a possible cause? #160 When operating under constant load, the superheated steam temperature may rise above normal if the _______________.#161 While steaming underway the second engineer reports a low superheater outlet temperature. Which of the following could be a possible cause?