Step 1 of 5•7 minutes read
Discharging Using FRAMO Pumps
As with all discharging events, care must be taken to set the operation up correctly before opening any valves or starting any pumps. The ship-shore checklist must be completed, agreed and signed before any operations occur. The ship must also have fully working inert gas systems and fire fighting and pollution prevention measures.
Using FRAMO pumps, though, does mean that the pumps do not need to be primed and lines filled before discharge. This means that the ship may be lined up and connected to the manifold earlier than usual, as there is no need to set up the discharge system before unloading.
A tanker is ready to discharge alongside an oil terminal. Photo Jörgen Språng.
Regular Discharge with FRAMO Pumps
When discharging, it is important to monitor the flow and pressures at all times to ensure that the cargo is being discharged correctly and there is no back-flow into the tanks. For single pump discharges, the following sequence should be used:
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Start the hydraulic power pack and increase the hydraulic pressure to 150 bar.
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Start the pump and allow it to run with 50 hydraulic bar pressure for about 1 minute to build system pressure.
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Open the discharge valve and monitor the system pressure.
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Increase the hydraulic pressure to the pump to maintain pressure above the manifold discharge pressure.
Discharging in this manner will ensure an even flow that can be safely monitored. Building up pressure in the lines initially will ensure that the head pressure up to the manifold should be overcome and avoid back-flow into the tank.
Discharge from Multiple Tanks in Parallel
Running pumps in parallel can be easily achieved by the FRAMO pump system. Multiple pumps can operate simultaneously if the cargo lines are of sufficient size and rating. When discharging homogenous cargoes saves time during the discharge as multiple tanks can be worked simultaneously.
However, the operator must be fully aware of the risks involved and the capacities and capabilities of both the ship and the shore reception lines. Hydraulic pressures must ensure no back or crossflow into the cargo tanks. Similarly, the pressures at the manifold and reception facility must be closely monitored to ensure maximum flow rates are not exceeded, leading to seal or valve failure.
When pumping in parallel, the following procedures should be used:
The starting procedure for each pump should follow the regular discharge procedure detailed above.
To avoid back or crossflow, the pump should be at an operating pressure higher than the manifold discharge before opening the discharge valve.
Pressures should be controlled by varying the pump speeds, not throttling the discharge valves or other valves.
It is generally recommended that as many pumps be used in parallel as possible during the discharge of homogenous cargoes. This allows for regulating flow rates by controlling the hydraulic pressure rather than the individual load balancing of each pump. For example;
...one pump running at 100% capacity would have the same discharge rate as two pumps running at 50% capacity.
This maintains a reduced hydraulic pressure, reduced speeds and reduced wear on the system itself.