SFO (Seal Flush oil) Unit: SFO unit is used to heat the cargo pump seals to the required temperature. The function of the seal flush pumps is to circulate seal flush oil (SFO) through the cargo pumps thereby heating up the cargo pump seal space and heat the remaining product in it. The SFO oil is heated by a heater which have direct thermal oil line from engine room via heater. SFO pumps should be kept running when cargo pumps are running even in both heated and unheated cargo mode and the temperature to be regulated as required by the cargo.
SHU (Secondary/ Separate Heating Unit): SHU is used to heat the cargo pump casing and cargo pump strainer (mud box). SHU pumps circulate the heated oil around the cargo pump casing and the strainer thereby increasing the casing temperature. This will cause the remaining product within the pump & strainer to liquify which can then be easily pumped without causing any damage to the pumps.
Secondary Heating System: Comprises of SFO unit and SHU unit.
It is very important to differentiate between heated and unheated cargos for various reasons. The secondary heating system must be kept running to keep the cargo pump and strainer heated at all time until vessel is trading in un-heated cargo mode.
Always start seal flush oil pump before turning on the thermal oil supply from Engine room to SFO heater. If carrying a low flashpoint cargo and cargo pump have already low flash point cargo inside the pump, the seal flush pump should still be started but the thermal oil supply for the seal flush oil heater should not be opened. In this case, the “Unheated cargo” mode must be activated in the EPS control panel. This will suppress an interlock present in the system, which will block start of the cargo pumps if the seal flush oil temperature is below 150-190 degrees Celsius (depending on the setting).
For Discharging Heated Cargo:
Prior Arrival Port:
- Confirm cargo pumproom fans are running for the interlock to permit operation of COP.
- Check and confirm the heat tracing lines to heat the cargo lines are open and all cargo line, valves are heated. Prior to testing the hydraulic valves on the line, it is necessary to initially test all manual valves to prevent potential valve damage. If a manual valve malfunctions, the corresponding hydraulic valve must not be operated until the manual valve issue is resolved.
- Confirm SFO and SHU is running, and required temperature is achieved to remove the interlock with the cargo pumps in heated mode, heater is ON.
- Cooling FW pump shall be started well before arrival.
- Check and confirm the oil level in the header tanks of SFO and SHU are sufficient to complete the cargo operation.
- Where provided, check and confirm the nitrogen pressure inside the header tank of SHU pump above 1.0 bar. (Nitrogen bottles are provided in 15K vessels for keeping the SHU pump head to required pressure.)
- Check and operate the cargo valve and confirm all cargo vales are freely operating.
- Check and confirm the cargo pumps are heated. SFO return temperature should be above the default interlock temperature.
- Check the cargo pump strainer is heated.
- Turn the cargo pump by hand and confirm free movement.
- The cargo pump temperature can be monitored from the HMI panel and should be same as the cargo temperature to be discharged.
- Check visually all cargo manifolds for any blockage.
Pre-Transfer Meeting:
- Confirm grades and corresponding tanks to be discharged with the terminal.
- Check for any terminal requirement and restriction for the port.
- Agree on the sequence of discharging, maximum manifold pressure and the rate of discharge.
- Any changes to Cargo Plan should be clearly discussed with the duty officers to avoid any misunderstandings or miscommunications.
- All OOW’s should familiarise with the contents of the pre-transfer meeting prior taking over watch.
- OOW should know the maximum running RPM and trip pressure of the cargo pump.
- OOW should know the maximum allowed suction pressure of the cargo pump.
- OOW should know the maximum bearing temperature of the cargo pump.
Manifold Connection:
- Check the shore hose/ loading arm for any visible blockage.
- Check the manifold presentation flange for smoothness and use new gasket when connecting.
- The gasket used must be rated for use at high temperatures. The discharge temperatures average around 150 Deg. C and may go up-to 210 Deg. C in case of cargoes like Coal Tar Pitch. Metal wound, graphite gaskets are the most suitable type.
- After Manifold is connected, carry out a Leak Test.
- Once confirmed there is no leak, install the splash guard on manifold and release the air as agreed with terminal.
- Adequate PPE must be worn when doing the manifold connection and disconnection.
- Cordo n off the manifold area just prior commencement of the discharging operation with effective means or warning rope (e.g., tiger rope).
- All cargo valves including manifold cross overs, line cross overs, main drop and discharge isolation valves, bottom cross overs, suction and drop valves shall be checked with compressed air to ascertain that there are no blockages or plugs in the line or valves. Same shall be done by pressurising the manifold line and releasing the pressure into the individual tanks and monitoring the rise in pressure which shall ensure that the lines are clear from manifold to bell mouth.
- Ensure that the cargo pump strainers are clear. Higher negative suction pressures and less discharge pressure during discharging is a clear indication of chock in strainers.
- Line/ hose Blowing of open-ended connections is STRICTLY PROHIBITED.
Before Discharging:
- The cargo valve line up to be checked visually by two different officers, one should be chief officer.
- After Ship Shore line up is completed & permission is received from the terminal, open the Manifold Valve.
- One person to be standby in pumproom and manifold during starting, changeover and stripping of cargo tank.
Discharging Operation:
- After confirming line up is done as per cargo plan, start the cargo pump with the bypass/ re-circulation valve open as these are positive displacement pumps.
- Once the cargo pump is stable and running at low RPM, slowly throttle and shut the bypass/ re-circulation valve to allow the cargo to pass through manifold and start discharging at agreed minimum rate/pressure.
- One man must be standby at the manual re-circulation valve until the terminal confirms receiving of product in the shore tank. Many a times, the shoreline is not adequately heated / have small stretches were heating arrangement is not fully covering and may cause blockage and result in pressure surge within the line.
- Vessel can increase to maximum discharging pressure after consulting with shore as agreed.
- Any changeover of cargo tanks to be done after reducing the RPM of the pump and informing the shore personal.
- Special attention to be given when shore using “booster pump”, always inform well in advance regarding changeover of tanks to shore and discuss same during pre-cargo meeting. Keep changeover to minimum when shore is using booster pumps.
- Continuously monitor the manifold pressure.
- When changing over tanks, valves of other tank to be opened first & once it is ascertained cargo is being discharged from the tank, then only the previous tank valves to be shut. Manifold pressures and pump suction pressures to be monitored continuously during tank change over. Special attention to be given for any vibration of cargo pump during changeover. A person to be standby in pumproom during changeover of cargo tanks.
- Never run the cargo pump with any valve shut in discharge side.
- Chief Officer to notify duty officers promptly of any changes to the cargo plan.
- No discharging operation to be carried out if the associated cargo tank gauge is faulty until the office has been informed and Risk Assessment has been made and approved by office.
- Use the alarm feature on Kongsberg Display for the Manifold Pressure and Ullages/volumes & set values accordingly for the discharging operation.
Completion of Discharging:
- Cargo tank stripping to be done at reduced/optimal RPM avoiding vibration. Stripping RPM can be obtained from cargo pump manual.
- Cargo pump suction pressure to be monitored. Most of the cargo pumps have suction pressure trip at -1.0 bar. Always check the manual and ascertain the value.
- Cargo pump may start vibrating when the suction pressure start reducing below -0.6 bar. Reduce the RPM of pump and avoid vibration. NEVER RUN COP UNDER VIBRATION.
- After completion of discharging, cargo line blowing to be done after getting permission from shore. All personal involved in line blowing should have adequate PPE.
- Line blowing from shore to ship to be carried out with manifold valve as a control point and all intermediate valves till cargo tank to be kept open under supervision of a responsible officer.
- Internal line blowing shall be carried out with manifold valves closed and air hose connected inboard of the manifold valves on both sides with intermediate valve till cargo tank opened. Either of the manual line crossover valve may be used as control point.
- If draining the loading arm by gravity, open the drop and intermediate valves to the tank, ensuring the manifold remains the highest point on ships end.
- Do not disconnect the manifold if there is any indication of product or pressure in the manifold line.
- SFO & SHU pumps shall be kept running at all times unless permission is sought from office, however the TOH temperature may be reduced to minimum as required for day-to-day operations.
- After departure from port, prior loading vessel shall ensure the strainer is cleaned.
For Discharging Unheated Cargo:
During the voyage, the vessel should recirculate cargo tank to tank to eliminate any possibility of previous cargo in the line or inside cargo pump and strainer. When handling unheated cargo SFO unit should be running always and temperature to be maintained as same as the cargo discharge temperature. Running of SHU system is not mandatory provided vessel to confirm the strainer and cargo pump are well flushed with flushing medium or the cargo itself.
Prior Arrival Port:
- Confirm cargo pumproom fans are running.
- Unheated mode is activated on the HMI panel which will bypass all the interlocks associated with the cargo pumps.
- Confirm SFO is running, and temperature is maintained as per the cargo discharge temperature.
- Check and confirm the oil level in the header tanks of SFO is sufficient to complete the cargo operation.
- Check and operate the cargo valve and confirm all cargo vales are freely operating.
- Check and confirm the cargo pumps are rotating freely by hand.
- Check the cargo pump temperature and maintained as per cargo discharge temperature and same can be monitored from the HMI panel.
Pre-Transfer Meeting:
- Confirm grades and corresponding tanks to be discharged with the terminal.
- Check for any terminal requirement and restriction for that port.
- Agree on the sequence of discharging, maximum manifold pressure and the rate of discharge.
- Any changes to Cargo Plan should be clearly discussed with the duty officers to avoid any misunderstandings or miscommunications.
- All OOW’s should familiarise with the contents of the pre-transfer meeting prior taking over watch.
- OOW should know the maximum running RPM and trip pressure of the cargo pump.
- OOW should know the maximum allowed suction pressure of the cargo pump.
- OOW should know the maximum bearing temperature of the cargo pump.
- Chances of leakage from flanges are high as cargo handled will be less viscous than the normal bitumen/pitch cargoes. Same to be discussed with all personal involved in the operation and frequency of rounds to be increased while discharging.
Manifold Connection:
- Check vessel presentation flange and shore hose/arm surface are smooth and new appropriate gasket in use.
- After Manifold is connected, carry out a Leak Test.
- Once confirmed there is no leak, install the splash guard on manifold and release the air as agreed with terminal.
- Adequate PPE must be worn when doing the manifold connection and disconnection.
- Cordon off the manifold area just prior commencement of the discharging operation with effective means or warning rope (e.g., tiger rope)
For larger Bitumen Carriers
General Lineup for Smaller Bitumen Carriers
Discharging MIMIC
