Question 37

The Correct Answer is B. Option B is correct because marine and power plant systems, especially those dealing with critical fluids like fuel oil, are designed with redundancy for reliability and safety. Fuel oil must be heated to the correct viscosity for proper atomization and combustion in the boiler burners. If the single operational fuel oil heater fails (due to leakage, scaling, or control failure), the standby heater allows operations to continue without interruption. Providing two heaters ensures that the required heating duty can always be maintained, fulfilling the critical function of providing a backup in case one of the heaters becomes inoperable. **Why the other options are incorrect:** * **A) To allow fuel of different temperatures to be provided to each boiler.** This is incorrect. Both boilers are typically supplied with the same type of fuel oil and require it to be heated to the same temperature (the temperature needed for optimal viscosity and combustion) before it reaches the burners. * **C) Two heaters are necessary when both boilers steam at full load.** This is incorrect. A single, properly sized fuel oil heater is designed to handle the maximum flow rate and heating requirement needed when both boilers are steaming at full load. The second unit is a standby unit, not a capacity booster required for normal operations. * **D) Each heater supplies fuel to a different boiler.** This is incorrect. Typically, the heaters operate in parallel, drawing from the same suction line and feeding into the common discharge header, which then supplies both boilers. They are arranged as duty/standby, not dedicated supply units.