Question 453Steam Plants - Assistant Engineer

The correct answer is D) fuel oil settling tank. The relief valve on the discharge side of the fuel oil service pump is designed to discharge to the fuel oil settling tank, in case of excessive pressure buildup in the fuel oil system. This helps prevent damage to the system and ensures a safe discharge location for the excess fuel. The other options are incorrect because: A) discharging to the suction side of the pump would create a recirculation loop, B) discharging to the fuel oil heater inlet could potentially damage the heater, and C) discharging to the double bottom fuel tank could lead to overfilling and safety concerns.