Fuel Oil Systems Fuel Oil Systems consist of: Storage Tanks Pumps Heaters Strainers Measuring and control devices Piping

Fuel Oil Tanks Fuel Oil Tanks are special compartments built into the structure of the ship for the express purpose of storing the ship’s fuel oil. Double Bottom Tanks Wing Tanks (outboard sections of the hull) Deep Tanks (large tanks above the inner bottom of the ship) Settling Tanks (tanks adjacent to the fire room)

Fuel Oil Tanks All fuel oil tanks must have vents and overflow connections. The vent shall not be less than the area of the filling line. All fuel oil tanks must be constructed in order to facilitate the free passage of air and gases from all parts of the tank to vent pipes.

Fuel Oil Tanks The vent pipe itself should run vertical, if possible, but if not run vertical, it must be inclined not less than 30° from the horizontal.

Fuel Oil Tanks Vents from fuel oil and other tanks extending above the freeboard or superstructure deck must be of substantial construction and the height from the deck to the opening at the inside of the return bend shall be at least 36 inches in well on freeboard decks, 30 inches on raised quarterdecks and 18 inches on other superstructure decks.

Fuel Oil Tanks Vent outlets must be fitted with a single screen of corrosion resistant wire, of at least 30 x 30 mesh or two screens of at least 20 x 20 mesh spaced not less than ½ of an inch nor more than 1 ½ inches apart.

Fuel Oil Tanks The vents shall have suitable ball check valve or other suitable approved device to prevent water from entering the vent during bad weather. Fuel oil tanks must provided with sounding devices for determining liquid level, In lieu of sounding pipes a reliable remote level indicator may be used.

Fuel Oil Tanks Provisions (striking plate) must be made to prevent damage to the vessels plating by the striking of the sounding rod. Heating coils are provided to heat the fuel and lower its viscosity to facilitate pumping operations

Settling Tanks Settling Tanks or Service Tanks are installed to provide a gravity head on the suction side of the fuel oil service pump. To maintain a reasonably large supply of oil for immediate use To provide a place where water and impurities may settle out of the oil. The settling tank are fitted with heating coils to preheat the oil and lower its viscosity, and thereby accelerate the settling out process.

Settling Tanks They generally have an overflow line connecting one settling tank to another or they can be arranged so that they can overflow to a separated overflow tank. Settlers are usually fitted with two suction valves a high and low suction valve. The low suction is usually used for normal operation. In the event of water in the fuel. Fuel oil service is switched to the high suctions.

Settling Tanks Valves for the high and low suctions shall be arranged for local control at the valve and remote control at a readily accessible and safe location.

Filling System Filling lines are provided to permit the transfer of oil to the storage tanks from a port facilities. The filling system generally has a deck connection on each side of the vessel piped to the filling and transfer manifold. From this manifold oil delivery to individual storage tanks is controlled.

Transfer System The fuel oil transfer system is the means by which oil is moved from one storage tank to another and from the storage tanks to the settling tanks. The transfer system consists of a pipe from each tank that connects to the suction and discharge (filling) manifolds of the transfer pump.

Transfer System Suction piping in the engine room runs from the suction manifold to the transfer pump and discharge piping connects the pump to the discharge manifold. The transfer pump is fitted with a suction strainer and a relief valve for protection of the piping and pump.

Fuel Oil Pumps Fuel oil service pumps take suction from the settling tanks and supply oil at high pressure to the boiler fronts. They are positive displacement rotary type which are designed to handle small volumes at high pressures. The pumps are fitted with a relief valve on the discharge side of the pump which is piped back to the suction side of the pump or to the settlers.

Fuel Oil Pumps Each vessel must have at least two fuel oil service pumps, each of sufficient capacity to supply all the boilers at full power. They shall be arranged so that one may be overhauled while the other is in service. Service pumps must be equipped with a means to secure the pump from a readily accessible position outside of the boiler room.

Fuel Oil Heaters At least two fuel oil heaters of approximately equal capacities are provided to heat the fuel oil to the proper temperature for most efficient combustion at the burners. They are arranged so that one may be overhauled while other is in operation.

Relief valves are fitted on the heaters to relieve excessive oil pressure to the settling tanks or the suction side of the pump.

Fuel Oil Strainers Fuel oil strainers are installed in the system to protect the pumps. valves, and atomizers from becoming damaged or clogged by mechanical impurities in the fuel oil. The strainers must be of the duplex type and are designed so that the oil flow is not disturbed when shifting from one strainer to the other for cleaning purposes.

Fuel Oil Strainers A coarse strainer is installed before the fuel oil pumps and a fine mesh strainer is installed after the fuel oil heaters since the oil is less viscous after heating.

Fuel Oil Piping All fuel oil discharge piping shall be schedule 80 seamless steel and must be readily observable Discharge piping from the fuel oil pump to the boiler installation shall be hydrostatically tested to a test pressure of 1 ½ times the maximum allowable working pressure or 500 psi which is ever greater.