Figure 2.1 Pre-treatment of marine fuels Preheating HEATING 怪 →|→
Figure 2.1 Preheating
2. 3 Pre-treatment of marine fuels Service systems: Service systems provide the final supply to the engine and should be designed to give a flow rate proportionate to the maximum fuel consumption Pumps for purification and engine fuel oil service systems must be capable of operating with the highest temperature of the fuel to be handled. Pressurized fuel systems are preferable when operating diesel engines on high viscosity fuels. When using high viscosity fuels requiring a preheat temperature far above 100C there is a risk of boiling or foaming if an open return pipe is used, and especially if there is water present in the fuel
2.3 Pre-treatment of marine fuels – Service systems: Service systems provide the final supply to the engine and should be designed to give a flow rate proportionate to the maximum fuel consumption. Pumps for purification and engine fuel oil service systems must be capable of operating with the highest temperature of the fuel to be handled. Pressurized fuel systems are preferable when operating diesel engines on high viscosity fuels. When using high viscosity fuels requiring a preheat temperature far above 100℃, there is a risk of boiling or foaming if an open return pipe is used , and especially if there is water present in the fuel
e.3 Pre-treatment of marine fuels Pressurized fuel system: In a pressurized fuel system, the fuel oil is gravity fed or drawn by a feed pump from the daily service tank, through a course strainer and a flowmeter to a mixing or return tank or pipe. From this tank a booster pump is delivering the fuel through preheater, viscosity controller and a fine filter to the engine fuel racks. about 30% of the fuel supplied by the booster pumps are consumed by the engine. while the rest is circulated back to the return tank or pipe through a return line. Normally there are two of each pump types and duplex strainers
2.3 Pre-treatment of marine fuels – Pressurized fuel system: In a pressurized fuel system, the fuel oil is gravity fed, or drawn by a feed pump, from the daily service tank, through a course strainer and a flowmeter to a mixing or return tank or pipe. From this tank a booster pump is delivering the fuel through preheater, viscosity controller and a fine filter to the engine fuel racks. About 30% of the fuel supplied by the booster pumps are consumed by the engine, while the rest is circulated back to the return tank or pipe, through a return line. Normally there are two of each pump types and duplex strainers
2.3 Pre-treatment of marine fuels Return tank/pipe: o Has a dual purpose: First, to ventilate vapors from the oil. second to serve as a reservoir when or if, switching from operation on heavy fuel oil to operate on diesel oil. Should have a capacity of 10 to 15 minutes of normal fuel consumption. ☆ Normal temperature range would be110to140℃ Pressure in order of 3 to 4 bars
2.3 Pre-treatment of marine fuels – Return tank/pipe: ❖Has a dual purpose: First, to ventilate vapors from the oil. Second, to serve as a reservoir when or if, switching from operation on heavy fuel oil to operate on diesel oil. ❖Should have a capacity of 10 to 15 minutes of normal fuel consumption. ❖Normal temperature range would be 110 to 140℃ ❖Pressure in order of 3 to 4 bars