It should be remembered that the main engine and the generator engines normally operate on HFO at all times and use the same fuel system. A change over to MDO may be made for the reasons given below and either the entire fuel system or the generator engine fuel system may be changed to MDO operation for normal use. It is possible to change just one generator engine to MDO operation and this would be done prior to shutting down for major maintenance. Two generator engine MDO service pumps are provided to flush MDO through a generator engine’s fuel system; there are separate HFO and MDO supply and return lines for each generator engine. In addition to the two electrically driven generator engine MDO service pumps there is an emergency pneumatically powered MDO service pump; this pneumatically powered pump provides for an MDO supply to the generator engines in the event of an electrical blackout.
The following procedure illustrates starting from cold, with the entire fuel system charged with MDO and in a shut down condition. This will only occur during dry docking when shore power is used; the generator engines would then be flushed through with MDO and would need to be changed over to HFO operation when the main fuel system is changed to HFO. The main engine is to be started on MDO and be changed over to HFO operation when
a) Start one of the HFO separators and fill the HFO service tank from the HFO settling tank, see section 2.7.2 of this machinery operating manual. Ensure that the MDO service tank has sufficient fuel for operating the main engine, replenish this tank if required.
b) Ensure that the fuel filters are clean.
c) Ensure that the HFO service tank is heated to the desired temperature and that trace heating steam is available at the HFO lines. A steam supply must be available for tank and trace heating.
d) Ensure control air is available.
e) Ensure that all instrumentation and control valves are open and that all instruments and gauges are reading correctly.
f) Set up the fuel system valves as in the following table:
note: It is assumed that the HFO service tank is to be used and circulating oil will return to this tank when the changeover to HFO operation is made.
position description Valve
Open HFO service tank quick-closing outlet valve F-101V Closed LSHFO service tank quick-closing outlet valve F-102V Closed HFO settling tank quick-closing outlet valve F-104V Open HFO settling tank outlet valve (to auxiliary boiler
FO pump)
F-241V
Closed LSHFO settling tank outlet valve F-110V
Open HFO settling tank to auxiliary boiler FO pump F-249V Closed MDO settling tank to auxiliary boiler FO pump F-241V Open MDO service tank quick-closing outlet valve F-103V Set 3-way valve (from either the LSHFO service tank
outlet or HFO service tank outlet) set to HFO service tank outlet
F-140V
Open Supply valve from MDO service tank located after MDO outlet valve
F-142V
Maersk Seletar Machinery Operating Manual
To Oily Bilge Tank (Dirty Side) To Overflow
Tank
Illustration 2.6.1a Main Engine Fuel Oil Service System
Key
Heavy Fuel Oil Marine Diesel Oil Compressed Air Steam Condensate Waste Oil Electric Signal
PIAL MC PX
Main Engine (HHI-Sulzer 11RT-Flex96C)
To Fuel Oil
Overflow Tank To Oily Bilge DrainTank
To Generator Engines
Heavy Fuel Oil Service Tank (188.3m3)
Heavy Fuel Oil Settling Tank (157.6m3)
Low Sulphur Heavy Fuel Oil Service Tank (157.6m3)
Low Sulphur Heavy Fuel Oil Settling Tank (157.1m3)
F-102V F-110V F101V
To Generator Engine Marine Diesel Oil Service Pumps
To Generator Engine Emergency Marine Diesel Oil Pump
F-104V
AuxiliaryTo Boiler Marine Diesel
Oil Service Tank (162.4m3)
F103V
To Fuel Oil Overflow Tank F-105V
F-107V
F-112V F-113V
F-249V F-241V
F-114V Fuel Oil Feed Pumps
(18.5m3/h x 5.0kg/cm2) PI F-106V
F-109V
F-108V
Control Air
Fuel Oil Booster Pumps (33.9m3/h x 12kg/cm2)
Fuel Oil Auto Backflushing Filter
Bypass Filter
PI From Generator Engines
F-185V F-139V F-130V
F-184V
F-226V Set at 6.5kg/cm2
Set at 5.5kg/cm2
Set at 12.0kg/cm2
F-148V
F-147V
MixingFuel Unit
TI
PI F-186V
F-228V
No.1 Fuel Oil Heater
No.2 Fuel Oil Heater
F-120V
Control Air
Condensate Flow Meter
Maersk Seletar Machinery Operating Manual
position description Valve
Closed Supply valve from HFO service tank located after the 3-way valve
F-141V Set 3-way control valve (enabling return to HFO
service tank or LSHFO service tank) set to return to the HFO service tank
F-139V
Closed Overflow valve to LSHFO service tank from the mixing unit
F-186V Closed Overflow valve to HFO service tank from the
mixing unit
F-185V Operational Fuel mixing unit overflow valve F-184V
Open No.1 FO feed pump suction valve F-105V
Open No.1 FO feed pump discharge valve F-107V
Open No.2 FO feed pump suction valve F-106V
Open No.2 FO feed pump discharge valve F-108V
Operational FO feed pump pressure relief valve back to suction (set to 5.0kg/cm2)
F-109V
Open Flow meter inlet valve F-112V
Open Flow meter outlet valve F-113V
Closed Flow meter bypass valve F-114V
Open FO mixing unit pressure indicator valve (6-PI-3) F-196V
Closed FO mixing unit drain valve F-228V
Operational FO mixing unit relief valve (set to 6.5kg/cm2) F-226V
Open No.1 FO booster pump suction valve F-116V
Open No.1 FO booster pump discharge valve F-118V
Open No.2 FO booster pump suction valve F-117V
Open No.2 FO booster pump discharge valve F-119V
Open Isolating valve to the pressure switch (4-PS-26) located on FO booster pump discharge
F-193V
Open No.1 FO heater inlet valve F-120V
Open No.1 FO heater outlet valve F-123V
Open No.2 FO heater inlet valve F-121V
Open No.2 FO heater outlet valve F-124V
Open Viscotherm inlet valve F-125V
Open Viscotherm outlet valve F-127V
Closed Viscotherm bypass valve F-126V
Set Automatic backflush filter valve
Open Backflush filter drain valve (locked open) F-129V Closed Isolating valve for sample valve (F-90V) after
automatic backflush filter (locked closed)
F-89V Open Main engine inlet quick-closing valve F-234V
Open Main engine fuel outlet valve F-146V
Open Main engine fuel bypass valve F-147V
position description Valve
Operational Main engine fuel bypass pressure controlled valve (set to 12kg/cm2)
F-148V Set Engine fuel backpressure valve (set to 5.5kg/cm2 ) F-130V
Open Return valve to FO mixing unit F-128V
The main engine is supplied with MDO from the MDO service tank via tank the generator engines should be supplied with MDO by the duty generator engine MDO service pump until the main engine is operating satisfactorily on HFO. Individual generator engines may then be changed to HFO operation off- load as described in section 2.6.2 of this machinery operating manual.
g) Check that there is sufficient HFO in the HFO service tank and that the fuel in the tank has been heated to the correct temperature.
h) Select the FO feed pumps and the FO booster pumps for Remote operation at their starter panels. At the Pump Control System mimic in the GOS select one FO feed pump and one FO booster pump as the master pumps. These pumps will start when selected as the lead pump. Select the second pump in each case as the standby pump. The standby pump will start if the lead pump fails to maintain the desired pressure and is activated by a pressure switch at the pump outlet.
MDO will be circulated through the fuel preparation module by the FO feed and booster pumps. This MDO will be circulated through the fuel lines to the main engine and will return to the fuel preparation module.
i) Start and run the main engine on MDO and ensure that it operates correctly. When the time has come to change over to HFO operation and the engine is operating steadily at below 75% MCR, proceed as follows.
j) Open the engine HFO line trace heating steam and drain valves together with the steam supply and drain valves for the fuel heaters.
k) Check that the trace heating lines are warm and that the HFO in the HFO service tank is at the correct temperature.
l) Open the HFO service tank line supply valve F-141V so that suction is taken from the HFO service tank. Close the cross-connection non-return valve from the MDO service tank F-142V, heated HFO will be drawn from the HFO service tank and will flow through the system. It will be mixed with returning MDO flowing back to the fuel mixing unit and the viscosity controller will monitor the mixture and adjust the steam supply to the heater in order to obtain the correct viscosity.
m) Monitor the engine operation for any abnormal conditions. The engine conditions will fluctuate slightly during the transition phase from MDO to HFO operation and exhaust temperatures and speed will vary slightly.
n) Gradually all MDO in the return line and the fuel mixing unit will be consumed and the engine will be operating on HFO with the viscosity controller maintaining the correct fuel viscosity.
o) When the engine is running under stable conditions on HFO, the load may be increased above 75% MCR to the desired value.
p) The outlet quick-closing valve F-103V from the MDO service tank must be left open as MDO is supplied to the generator engines in the event of a blackout.
q) The main engine is now operating on HFO.
note: The vent valve F-184V at the top of the fuel mixing unit must be open at all times together with the return valve to the operating HFO service tank, F-185V for the HFO service tank or F-186V for the LSHFO service tank.
CAUTION
trace heating should not be applied to sections of pipeline isolated by any closed valves on the fuel oil side as damage may occur due to the restricted expansion of the contents.
As both the main engine and the generator engines take fuel from the same fuel preparation module, changing from HFO to MDO or vice versa will cause both engine systems to operate on the same fuel. The main engine and generator engines are designed to run on HFO at all times. However, changeover to MDO may become necessary if, for instance, the engine in question is expected to have a prolonged inactive period due to major repairs of the fuel oil system etc., or a dry docking resulting in a prolonged stoppage of the main engine.
Additionally, environmental legislation may require the use of low sulphur fuels. If there is a need to change the main and generator engines to MDO for environmental or other reasons, the entire fuel system may be charged with LSHFO or MDO as explained below.
Maersk Seletar Machinery Operating Manual
To Oily Bilge Tank (Dirty Side) To Overflow
Tank
Illustration 2.6.1a Main Engine Fuel Oil Service System
Key
Heavy Fuel Oil Marine Diesel Oil Compressed Air Steam Condensate Waste Oil Electric Signal
PIAL MC PX
Main Engine (HHI-Sulzer 11RT-Flex96C)
To Fuel Oil
Overflow Tank To Oily Bilge DrainTank
To Generator Engines
Heavy Fuel Oil Service Tank (188.3m3)
Heavy Fuel Oil Settling Tank (157.6m3)
Low Sulphur Heavy Fuel Oil Service Tank (157.6m3)
Low Sulphur Heavy Fuel Oil Settling Tank (157.1m3)
F-102V F-110V F101V
To Generator Engine Marine Diesel Oil Service Pumps
To Generator Engine Emergency Marine Diesel Oil Pump
F-104V
AuxiliaryTo Boiler Marine Diesel
Oil Service Tank (162.4m3)
F103V
To Fuel Oil Overflow Tank F-105V
F-107V
F-112V F-113V
F-249V F-241V
F-114V Fuel Oil Feed Pumps
(18.5m3/h x 5.0kg/cm2) PI F-106V
F-109V
F-108V
Control Air
Fuel Oil Booster Pumps (33.9m3/h x 12kg/cm2)
Fuel Oil Auto Backflushing Filter
Bypass Filter
PI From Generator Engines
F-185V F-139V F-130V
F-184V
F-226V Set at 6.5kg/cm2
Set at 5.5kg/cm2
Set at 12.0kg/cm2
F-148V
F-147V
MixingFuel Unit
TI
PI F-186V
F-228V
No.1 Fuel Oil Heater
No.2 Fuel Oil Heater
F-120V
Control Air
Condensate Flow Meter