MAN Lube Blending Unit in Service Tests
A new cylinder oil blending unit, Man Diesel & Turbo is service testing, intended to simplify the lubrication aspect of fuel switching, with containership owner Costamare. The automatic cylinder oil mixing (ACOM) structure comprises of three small tanks holding low base number (BN), high BN and blended oils. Produced on the optimal cylinder oil feed rate factor along with sulphur of fuel currently in use, ACOM blends cylinder oil to the suitable BN and analyses the lowest possible optimum feed rate.
The ACOM unit substitutes the heating tank presently positioned before the engine and eradicates the necessity for a day tank for cylinder oil, with the base oils being taken directly from cylinder oil storage tanks. After prototype step, controls for the ACOM unit will be incorporated into the electronic control system of MAN’s ME engines and are controlled from the main operating panel.
The first ACOM unit set to go through service testing has been mounted on a 26,000 dtw oil tanker with a MAN B&W 6S50ME-B8 main engine for more than six months without mechanical issues. A second ACOM system has also commenced its service test in a vessel with a MAN B&W 5S60ME-C8.2 main engine.
At CIMAC Congress in June, a paper presented, by MAN Diesel & Turbo used an operational case from containership owner Costamare, which is trialling the unit, to emphasise the need for ACOM.
“Most of the Costamare vessels trade regularly in sulphur emission control areas and switch to either gas-oil or hybrid fuel with less than 0.1% sulphur. At the same time the vessels switch from BN100 to BN25 cylinder oil. Some vessels trade in South America and bunker low sulphur HFO with sulphur percentages typically ranging from 1-1.5%. Ideally, such fuels require third cylinder oil with a BN of around 40. That would require three grades of cylinder oils, which logistically is difficult.”
With potentially saving significant cylinder oil consumption and optimising cylinder condition, the ACOM unit will also confirm a quick changeover process from high to low BN or vice versa, as it operates continuously with only a lesser mixing volume.
So far MAN has been testing the unit with oils up to BN100. But the company observed that BN140 oils – beyond the usual BN range of cylinder lubricants – could allow minimum feed rate to be sustained at higher sulphur levels.
“Calculations show that this will be a good business case for high sulphur fuels as lube oil dosage can be lowered, and at the same time the ACOM system may protect the engine from possible bore-polish as the BN will be reduced at lower sulphur contents.” the company added.
As a result, MAN reported that it has been testing several brands of BN140 cylinder oils.
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Source: Motor Ship
