武汉理工大学：《船舶辅机》课程教学资源（PPT课件，英文版）2.2 Fuel storage and pumping Onboard

2.2 Fuel storage and pumping Onboard s Learning Objectives The learning objectives of this section are to make all engineers, engine cadets and other crew members who are involved in the handling of fuels on board, familiar with: How to handle the fuel Take the necessary simple precautions by following test procedures To evaluate and find the correct temperatures of the fuel related to storing and pumping. To undertake the correct operation when performing stripping and trimming

2.2 Fuel storage and pumping Onboard • Learning Objectives The learning objectives of this section are to make all engineers, engine cadets and other crew members who are involved in the handling of fuels onboard, familiar with: – How to handle the fuel. – Take the necessary simple precautions by following test procedures. – To evaluate and find the correct temperatures of the fuel related to storing and pumping. – To undertake the correct operation when performing stripping and trimming

2.2 Fuel storage and pumping Onboard Storage temperatures 1. In general, bunkers should be stored at temperatures that allow reliable pumping while preventing build-up of wax in tank bottoms 2. The use of bunker tanks for water ballast should be avoided 3. The storage tanks should be maintained at a temperature that allows the fuel to be pumped or moved by gravity, without undue difficulty. 4. A temperature of about 45C will normally ensure good flow and pumping conditions

2.2 Fuel storage and pumping Onboard Storage temperatures 1. In general, bunkers should be stored at temperatures that allow reliable pumping while preventing build-up of wax in tank bottoms. 2. The use of bunker tanks for water ballast should be avoided. 3. The storage tanks should be maintained at a temperature that allows the fuel to be pumped or moved by gravity, without undue difficulty. 4. A temperature of about 45℃ will normally ensure good flow and pumping conditions

Table 2. 1 Heating requirements for pumping ⅵ iscosity, cSt at50 700 500 380 180 100 20 Temperature

Table 2.1 Heating requirements for pumping the

2.2 Fuel storage and pumping Onboard · Heating and cooling Storage heating capacity should be capable of raising the fuel temperatures to 45C 2. With high pour point waxy fuels, the temperature should not be allowed to approach the pour point. Otherwise, when the fuel is reheated for pumping, there may be great difficulties in reeling the wax structures that have formed in the tank 3. If the fuel has been allowed to cool however, extended heating time may be needed to dissolve all the wax in order to avoid filter blocking

2.2 Fuel storage and pumping Onboard • Heating and cooling 1. Storage heating capacity should be capable of raising the fuel temperatures to 45℃ 2. With high pour point waxy fuels, the temperature should not be allowed to approach the pour point. Otherwise, when the fuel is reheated for pumping, there may be great difficulties in remeling the wax structures that have formed in the tank. 3. If the fuel has been allowed to cool however, extended heating time may be needed to dissolve all the wax in order to avoid filter blocking

2.2 Fuel storage and pumping Onboard NOTE: fuel oils should never be heated to more than 10C below the actual flash point Heating coils should extend all over the tank bottom area to ensure that wax can be dissolved. If heaters are situated at the outflow only, wax may build up elsewhere in the tank Fuel tank heating coils: The storage tanks are heated by means of steam, and two kinds of leakage problems may occur:

2.2 Fuel storage and pumping Onboard • NOTE: fuel oils should never be heated to more than 10℃ below the actual flash point. Heating coils should extend all over the tank bottom area to ensure that wax can be dissolved. If heaters are situated at the outflow only, wax may build up elsewhere in the tank. • Fuel tank heating coils: The storage tanks are heated by means of steam, and two kinds of leakage problems may occur:

2.2 Fuel storage and pumping onboard Water is disappearing from the feed water system. If water disappears from the feed water system: Check for steam leakage in the visible system. If not found, the leakage may be inside one of the tanks which means that steam is leaking into the fuel oil. The process of locating the leakage will be very time consuming, and when located, that particular part of the heating system must be isolated. The result may be that the fuel in the actual tank will be difficult to handle because of the lack of heating

2.2 Fuel storage and pumping Onboard • Water is disappearing from the feed water system. If water disappears from the feed water system: Check for steam leakage in the visible system. If not found, the leakage may be inside one of the tanks, which means that steam is leaking into the fuel oil. The process of locating the leakage will be very time consuming, and when located, that particular part of the heating system must be isolated. The result may be that the fuel in the actual tank will be difficult to handle because of the lack of heating

2.2 Fuel storage and pumping onboard Oil is spotted in the feed water. If oil is spotted in the feed water: Lack of maintenance of the heating system may cause leakage, which means that fuel oil is leaking into the heating system. It is possible to discover this kind of leakage by performing regular inspections of the cascade tank water, steam traps, etc. at the suction side of the pumps. The process of locating the leakage will be very time consuming, and when located, the actual part of the heating system must be isolated. The result may be that the fuel in the actual tank will be difficult to handle because of lack of heating Maintenance and regular inspection of the fuel tank heating systems must be considered as good economy

2.2 Fuel storage and pumping Onboard • Oil is spotted in the feed water. If oil is spotted in the feed water: Lack of maintenance of the heating system may cause leakage, which means that fuel oil is leaking into the heating system. It is possible to discover this kind of leakage by performing regular inspections of the cascade tank water, steam traps, etc. at the suction side of the pumps. The process of locating the leakage will be very time consuming, and when located, the actual part of the heating system must be isolated. The result may be that the fuel in the actual tank will be difficult to handle because of lack of heating.Maintenance and regular inspection of the fuel tank heating systems must be considered as good economy

2.2 Fuel storage and pumping Onboard Bunker segregation plan All ships should have a plan for segregation of fuel oil in order to: Prevent usage of fuel until test results are received Always keep track of the fuels Prevent accidental mixing of non compatible fuels

2.2 Fuel storage and pumping Onboard • Bunker segregation plan All ships should have a plan for segregation of fuel oil in order to: ❖ Prevent usage of fuel until test results are received ❖ Always keep track of the fuels ❖ Prevent accidental mixing of non￾compatible fuels

2.2 Fuel storage and pumping onboard .. Tank to tank operations Cleaning intervals of tanks All ships should have a plan for cleaning intervals of fuel tanks. The fuel tanks should normally be cleaned during every docking. Nevertheless it must be an established routine to carry out tank inspections, in between dockings

2.2 Fuel storage and pumping Onboard • Tank to tank operations – Cleaning intervals of tanks: All ships should have a plan for cleaning intervals of fuel tanks. The fuel tanks should normally be cleaned during every docking. Nevertheless it must be an established routine to carry out tank inspections, in - between dockings

2.2 Fuel storage and pumping onboard Sediments and rough weather mixing Water and sediments already settled in the tan ks, are likely to be mixed back into the fuel, when sailing with slack tanks in rough weather. If this occurs in the settling tank, the fuel should be given a prolonged settling period, if possible before being transferred to the service tank If an emulsion should occur, it may be possible to dissolve this by adding certain additives to the fuel, but only if advised to do so from head office

– Sediments and rough weather mixing: Water and sediments already settled in the tanks, are likely to be mixed back into the fuel, when sailing with slack tanks in rough weather. If this occurs in the settling tank, the fuel should be given a prolonged settling period, if possible before being transferred to the service tank. If an emulsion should occur, it may be possible to dissolve this by adding certain additives to the fuel, but only if advised to do so from head office. 2.2 Fuel storage and pumping Onboard