Bunkering Operation
How to order bunker:
1. Take essential data from master, such as distance to go with average speed, river passage, pilotage, port stay, etc. To check ROB.
2. Estimate HO and DO consumption based on weather, wind and current condition, running hours of AEs auxiliary boiler and ME.
3. Estimate the 3 days reserve, considering unpumpable quantity, bunker allowance or bunker margin.
4. Calculate the capacity to receive, bunker amount, type of bunker, HO, DO or LO.
5. Bunker should be allowed 85% of tank capacity.
6. Arrange not to mix with remaining onboard fuel.
Total required bunker from port to port = {Distance to go with average speed + River
Passage + Pilotage + Port Stay + 3 Days Reserve }
Bunker to be ordered: = { Total required – ROB }
CE’s Responsibility during Bunkering:
CE is overall in charge of bunkering.
Responsibilities are:
1. Fire prevention
2. Oil pollution prevention
3. Calculation
4. Recording and informing.
Discuss at Bunkering Meeting about: Quantity / Bunkering Sequence / Distribution Plan.
Make preparations for both Deck and Engine Department, in accordance with pre-bunkering checklist.
Prepare all necessary papers as per local regulations.
Fire Prevention:
1. Prohibit naked light and smoking around bunker area.
2. Place portable fire extinguisher at bunker point.
3. Bunker oil flash point ≮ 65°C, as a rule.
4. Ensure no oil leakage.
Pollution Prevention:
1. Clear overflow tank and top up settling and service tank.
2. Clean System filters, sight glass, and pressure gauge in good order.
3. Ensure bunker system valves in good order, and the correct valves have been opened.
4. Take all soundings of fuel tanks, and calculate the amount to be put into each tank.
( 85% of tank capacity is maximum. )
5. Explain bunkering sequence to all engineers.
6. Check security of hose coupling, and one responsible engineer to be stand-by at bunker station to watch break or spill at hose connection.
7. Agree the pumping rate or pressure with pump man or barge master, remembering that a burst hose can cause pollution. Discuss slow down operation and emergency stop procedure.
8. Make good communication between bunker point, barge or shore supply, and tank control station.
9. Leakage or overflow of oil to deck strictly prevented. Saw dust, OSD, and rags, ready at bunker point.
10. Duty officer to be informed, the amount to be bunkered and expected time of the work.
11. Plugged all deck scuppers.
12. Maintain the upright position as possible as.
For Calculations:
1. Take all soundings of fuel tanks, before and after bunkering.
2. Take fore and aft draughts, before and after bunkering.
3. Take soundings of barge or to check flow meter reading, before and after bunkering.
4. Record the oil temperature.
5. Calculate corrected sp.gr. at measuring point temperature, SGc.
6. By multiplying SGc with total volume, obtained from sounding table, total amount of bunker in tons will be obtained.
Bunker Barge Arrival:
1. Record exact time of barge arrival and departure.
2. Check local supplier’s paperwork, to ensure that specification and quantity ordered is correct.
3. Check for correct specification, and compatibility tested, by using a test kit.
4. Check water content of bunker is at acceptable level.
5. Ensure that onboard fuel handling equipment is adequate and serviceable at all times.
Bunkering:
1. Start bunkering at slow rate, and then raise the pumping rate.
2. Always check and witness the flow meters, tank gauges and tank dips, before and after delivery, to ensure that the right quantity has in fact been supplied.
3. Random checks to ensure correct specification of oil being supplied during bunkering.
4. Take a continuous drip sample. Compatibility test of bunker carried out.
5. Always insist on being given a sealed sample of bunkers delivered, which should be witnessed and signed by both parties.
6. When 80% of total capacity reaches, pumping rate slow down and final topping up done.
After Bunkering:
1. Record the time and read flow meter on bunker boat or on shore.
2. All filling valves kept open, until final air blowing is completed.
3. Remain hose connections until correct quantity of oil has been received after calculation.
4. Then close bunker main valve, system valves and individual tank valves.
5. Take final soundings and bunker temperature from both ship and barge to calculate actual amount.
6. When calculating the bunker received, the ship’s trim and temperature of the oil must be taken into account.
7. Both party signed on sample bottles and sent to laboratory. The statutory sample to be kept in sample store and retain it for 12month.
8. Inform duty officer, starting and stopping time, amount of bunker received and tank soundings, for stability calculation and custom claiming purposes.
9. Make entries into ORB, Sulphur record book and Logbook.
10. BDN to be collected from supplier and file it properly to retain it for 3 years.
10. Prepare Bunker Report and sent to HO.
FO Overflow while Bunkering: [Action taken by CE.]
1. Stop pumping of fuel immediately.
2. Report to Master and contact Port Authority or persons concerned, about oil pollution incident.
3. Detail description of actions taken immediately by crew, using equipment from Oil Spill Locker to reduce and control the oil flow.
4. Arrange point of contact onboard, for co-ordinating shipboard action with local authorities, in combating pollution.
5. Make entry into ORB, date, time, place and amount of overflow.
Bad fuel:
1. Bunker should be received in empty tank and made segregated.
2. During bunkering, compatibility test should be done.
3. Sealed sample sent to laboratory for analysis.
4. Maintain storage temperature well above pour point. (About 40’/50’C under coldest climate condition.)
5. Settling tank temperature maintained about 14’C below flash point to improve gravitational separation. Regular drain out of water and impurities.
6. Fuel transfer lines steam traced, and transfer pump suction filter cleaned.
7. If necessary, dose chemicals, e.g. Gamma Break- Unitor, into storage tanks ( DB tanks) by using dosage pump for chemical.
8. Regular cleaning of coarse filters.
9. Two purifiers run in parallel, to get enough fuel for engine, with optimum throughput and correct heating temperature (98’C). Gravity disc, carefully chosen. If necessary, double stage centrifuging will be done with purification and clarification in series.
10. Maintain correct service tank temperature. Dose some chemicals, to improve combustion efficiency. (Duel Purpose Plus, Unitor)
11. Maintain correct oil temperature, to get suitable viscosity at injectors,
( 10 ~ 18 Cst.). Fuel outlet from heater, controlled by Viscotherm Unit.
12. Steam tracer lines correctly heated, up to injector.
13. Maintain correct working temperature of engine, to prevent hot and cold corrosion due to Vanadium and Sulphur attacks.
14. Check engine performance by taking indicator diagram.
15. If damage occurred due to bad fuel, prepare for insurance claim.
Compatibility:
1. Ability of two fuel to be blended together without precipitation of sediments, such as asphaltine and sludge, etc.
2. Due to asphaltine and sludge, it can cause choking of filters, overloading of purifier and immobilization of vessel in severe case.
Remedies: For Incompatibility:
1. Keep fuels in empty tank and segregated.
2. Always carry out compatibility test when bunkering.
3. Incorporate homogenisation system to completely mix incompatible fuel components prior to injectors.
Compatibility Test:
1. Pour 40 ml of sample into test tube. (20 ml for each fuel)
2. Add reagent of white spirit up to 80 ml. (ē 40 ml white sprit)
3. Then the mixture is mixed well.
4. One drop of mixture is deposited on chromatographic paper and allowed to dry at room temperature.
5. Then test drop is compared with five standard spots.
Spot 1 ~ 2 indicate compatible fuel.
Spot 3 ~ 5 indicate incompatible fuel.
Requirements for the use of high viscosity fuel:
1. Bunker tank-heating systems capable of maintaining fuel temperature about
40-50’C higher than Pour Point under the coldest climate condition.
2. Exposed bunker transfer pipes insulated and trace heated.
3. Treatment plant capable of purifying/clarifying high density fuels.
4. Engine preheaters designed to achieve recommended injection viscosity.
5. Trace heated and pressurised engine fuel system, allowing manoeuvring on residual fuel.
6. Main and auxiliary engine designed to burn high viscosity fuel oil.
Effects of Bad Fuel Oil:
1. Too much sludge formation in DB tank.
2. Frequent fuel line filter blockage.
3. Upsetting purifier.
4. Premature wears of fuel pump.
5. Carbon trumpet formation and leaky FV.
6. Excessive wears and cold corrosion of cylinder liner.
7. Excessive carbon deposits in piston rings.
8. Hot corrosion attack on Exhaust valve.
9. Choked turbine nozzle rings and broken blades.
10. Excessive carbon deposits on EGE.
Bunker Specifications:
Includes: Name of vessel, Port of bunker, Date of delivery, Product name, Temperature of product, Sulphur Content,
Quality:
1. SG at 15°C
2. Viscosity at 50°C
3. Sulphur content % by weight
4. CCR % by weight
5. Flash Point [closed] °C
6. Pour Point °C
7. Water content % by volume
8. Sludge / Sediment % by weight
9. Cetane No.
10. Vanadium in ppm.
Bunkering:
1. Slow rate and record.
2. Take soundings.
3. Random check
4. Continuous drip sample.
5. Compatibility test
6. Slow down when 80% is reached.
7. Remain v/vs opened until after air blow.
8. Remain hose connection until after calculation.
9. Take sealed sample
10. Close all valves.
Viscotherm Unit:
A device to adjust the viscosity of oil to get desired value, which is essential for correct atomisation and combustion of engine.
Operation:
1. Constant quantity of oil is taken from the flow and fed into capillary tube by means of motor operated gear pump through reduction gear.
2. Oil flows through capillary tube under laminar condition and pressure drop across the tube is measured by DP cell and its signal is directly proportional to oil viscosity. A transducer is incorporated with DP cell.
3. Signal given by DP cell is compared with a set value and any deviation can cause
drive signal to adjust pneumatic control steam inlet valve to oil heater.
4. Normally the required injection viscosity is 10 ~ 18 Centistrokes and required value is set at transducer.
VIT:
1. Load-dependent start of fuel injection control system.
2. VIT mechanism automatically change the fuel injection timing, according to load,
to get maximum combustion pressure (Pmax) at engine load between 85% ~ 100%.
3. Reduction in SFOC is about 2.0 gm / bhp / hr at 85% engine load.
4. VIT fuel pump incorporates variable injection timing with optimised fuel economy,
at part load.
5. Expansion Ratio is increased.
Maximum Pressure
Expansion Ratio =
Pressure at the start of Exhaust Blow-down
6. Required fuel viscosity at engine inlet is 10 ~ 20 Cst.
In other words:
1. If an engine running at prolong period at reduced load, lower air temperature after compression, will cause increase in ignition delay of injected fuel, subsequently causing knocks and poor combustion.
2. This problem can be reduced by adoption of VIT system, to advance the start of injection, then allowing the same Pmax, at part load.
Operation of VIT: [ Valve control type: Sulzer RTA ]
1. Fuel Quality Setting [FQS] lever is used for manual adjustment of VIT mechanism to alter valves timing, according to ignition quality of fuel used. [If poorer quality fuel is used at same valve timing, Pmax will drop, and with better ignition quality fuel, Pmax will rise.]
2. VIT mechanism is linked to Governor Load Setting Shaft and built-in cam system, which is positioned by FQS lever.
3. This mechanism controls the timings of Suction Valve closure (beginning of delivery) and Spill Valve opening (end of delivery) through linkages simultaneously.
4. Hence, fuel injection timing, Pmax, and fuel delivery to injectors, are controlled load-dependently.
Thermal Cracking:
1. Atoms within hydrocarbon molecule are excited by heating, thus lighter fraction of molecule breaks-off and condensed.
2. Remaining portions of original molecule then unite to form more heavier molecule.
3. Thermal cracking produces Asphaltene, which has heavy hydrocarbon molecules,
causing slow burning in fuel combustion.
