Switching fuel for MARPOL Compliance. The “Kuala Lumpur Express”, a 8,750-TEU Hapa-Lloyd fleet vessel operating between Northern Europe and the US East Coast, like many vessels sailing on the maritime areas known as ECAs, switches to low sulphur Marine Diesel Oil to achieve MARPOL compliance.
She repeats this process four times per tour, according to an article published in Ship and Bunker explaining the cumbersome, highly precise, and time-consuming procedure.
The process starts around 24 hours before the ship reaches the ECA border with a message from the nautical-officers. “The nautical officers tell us when we will be reaching the border. And from that point in time we calculate backwards,” explains Chief [Engineer Karsten ] Bartlau. Together with the third engineer, he immediately starts making preparations. To begin with, they slowly reduce the temperature in the HFO service tank to 120 degrees Celsius and raise the temperature in the MDO service tank to 45 degrees Celsius. This ensures that the temperature difference between the two fuels is only around 75 degrees. This provides a significant advantage. “The difference in temperature between fuel that has just been used and new fuel is one of the most important determinants,” says Bartlau. The change of temperature gradient in the main engine should never be more than two degrees Celsius per minute at the most, as sudden changes can lead to leakage and in the worst case to a piston seizing.
And there’s more.
Through a fuel changeover calculator engineers gauge the exact duration for this process, with “software specifically customized to each individual ship in the fleet”, the note says.
In the example shown, the switch-over period for the “Kuala Lumpur Express” lasted exactly three hours and 41 minutes. As this is a relatively new vessel, the changeover on this ship is very fast. On other ships that are older, the entire process can take anything up to 72 hours.
The Hapag-Lloyd fleet consists of 175 modern container ships, transporting 7.5 million TEU (Twenty-foot Equivalent Unit) a year.
And there’s even more.
The Chief and the third engineer need around five hours to prepare for the changeover. At that point, they need to shuffle with hot steam supplies, opening of the MDO valve, shutting down of the HFO valve, a process repeated several times.
At this point, the note in Ship and Bunker continues, inspectors can come on board and take fuel samples to ensure that the vessel is compliant with MARPOL regulations.
It’s a numbers game and miscalculations will be costly:
When entering Emission Control Areas, the challenge lies in completing the fuel changeover just a few minutes before crossing the border. If the chief engineer begins the changeover process prematurely, then he is literally burning money. Just one hour too long is tantamount to a four-digit dollar amount. When leaving the zone, the primary goal is to avoid damaging the engine’s components through the changeover from cold MDO to hot HFO. That is why the “two degrees per minute” rule also applies in this case. Chief Bartlau says: “On our first few trips the changeover was quite an exciting process. No one knew how the main engine and the aggregates would respond. But now with our vast know-how, we’ve established a very conscientious routine here on board.”
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