Question 7Steam Plants - Assistant Engineer

The correct answer is D) produces a higher oil temperature at any given steam temperature. In a counter-flow fuel oil heater, the hot steam and the cold fuel oil flow in opposite directions, allowing for more efficient heat transfer. This results in the fuel oil reaching a higher temperature at any given steam temperature compared to a parallel-flow heater, where the steam and fuel oil flow in the same direction. The other options are incorrect because: A) While a larger heat transfer area can improve efficiency, it is not the primary advantage of a counter-flow heater. B) Both counter-flow and parallel-flow heaters can be susceptible to coking if overheated. C) Tube wall thickness is not the main factor that determines the heat transfer efficiency of the heater.