How to get the right BN cylinder oil? Blend your own

SEA-Mate B1000 on-board cylinder oil blending system

OCTOBER 11, 2016 — With current industry concerns about cold corrosion, and the need to adjust fuel sulfur levels to meet emissions limits, the importance of using cylinder oil of the correct alkalinity level has never been greater. A simple, flexible, reliable and environmentally-friendly method of achieving this is through Blending-on-Board (BOB).

BOB was developed in 2008 by Maersk initially for the A.P Moeller group’s own ships, and over 200 installations in Maersk and other fleets have now logged millions of cylinder operation hours.

The technology has proved reliable, and the third generation is commercially available.

It is being shown at this month’s Danish Maritime Fair (Stand number 0520) in Copenhagen under the SEA-Mate brand name by Maersk Fluid Technology which will present examples of the system and the associated XRF scrapedown oil analyzer.

The product line includes a new blender, the SEA-Mate B500, which is specifically designed for engines with a bore size 26 – 48. With the new unit, along with its larger alternatives, the SEA-Mate B1000, bore size 50 – 72 & B3000, bore size >72, there is now a suitable SEA-Mate blender for all two-stroke engines.

BOB has been used with both Wärtsilä/WinGD and MAN B&W engines, and both companies have issued letters of no objection to the use of the technology.

The system utilizes the in-use system lubricant as base stock, and blends it with a high-alkalinity (which may be as high as 300BN) cylinder oil concentrate to produce a cylinder lubricant with the optimum base number (BN), anything from 40BN up to well above 100BN.

“When switching from traditional lubrication oil to our future-proof blending system, experience with the current 200 installations has proved that it will be possible to achieve lubrication at or close to the lowest allowed consumption of lubricant as specified by the engine manufacturer,” says Sune Lilbaek, Head of Sales at Maersk Fluid Technology. “This results in the cylinder lubricant from the BOB system always matching the sulfur content in the fuel. It is no longer necessary to increase lubricant supply to counter corrosive wear or fouling – instead the concentration of BN and other additives are adjusted on-the-fly, creating a fit-for-purpose cylinder oil at same or better quality than a standard fixed-BN cylinder oil. Being able to match lubricant with the fuel in use translates to proven reductions of up to 40% in cylinder oil consumption. Once the system has been set up, on-board engineers will merely need to enter the sulfur content of the fuel in use and the system will automatically blend a cylinder oil matching the fuel sulfur – the process can be fully automated and does not require interaction from the operator. “

As the oil used for blending down the concentrate is taken from the in-use system oil, system oil is frequently replenished with new stock. This prevents the oil quality deterioration that otherwise takes place for any system oil. As a result, anti-wear and detergency properties are as for a new oil and on top of this, the system oil viscosity is maintained and waste system oil disposal and oil cleaning energy consumption is reduced by up to 80%.

Experience has shown that by maintaining the original viscosity of the system oil, friction losses are reduced and fuel consumption has proven to be cut by up to 1.5%. Cleaner system oil has, in addition, a positive impact on wear of components and maintenance of separators and filters. Taking into account the reduced fuel and lubricating oil consumption and lower waste oil disposal costs, payback times of less than two years can be expected.

The SEA-Mate M4000 XRF analyzer, which will also be on display at the Danish Maritime Fair, is an accurate lubricant analysis tool that can provide accurate and reproducible results within seven minutes, rather than the average two-week delay in obtaining laboratory results. Although it is perfectly possible to utilize BOB without the analyser, including the M4000 as part of the system facilitates fast and precise evaluation of every lubrication adjustment made.

Sea-Mate M4000 XRF oil analyzer

Maersk says the M4000 is the only system intended for onboard use which gives a precise on-board measurement of both corrosive and abrasive iron in scrapedown oil, making it possible to identify if corrosive wear is taking place and take appropriate action without delay.