Choosing cylinder oil lubricants for ships is becoming increasingly complex. Selecting a cylinder oil that is compatible with changing marine fuels, the use of emission reducing technologies and evolving engine designs can be a difficult process to navigate.
Future proofing ships for operating demands and regulatory requirements in the future that drive down the sulphur content in fuels is difficult. When it comes to lubricants, considerations for future operating profiles, fuel selection and requirements for a ship and its engine machinery are vital. The selection of a less than suitable lubricant can be seriously detrimental to the proper functioning of a ship’s engine, not to mention costly if damages are incurred.
The Impact of a Changing Regulatory Landscape
Regulatory demands that govern shipping emissions have namely accelerated the use of low-sulphur bunker fuels and the adoption of larger stroke-to-bore ratio engines. Strategies such as slow steaming have been welcomed by the industry, not just as a reaction to historically high fuel prices encountered but also as a means to reduce emissions for regulatory compliance. Changes in bunker fuel use and engine operating conditions greatly impact the functionality of the cylinder oil lubricant. Recognising and opting for cylinder oils that are designed to be compatible with and possess the ability to operate seamlessly with specific engines types, operating conditions and fuel types is paramount to avoiding machinery damage and long-term operational complexities.
The Impact of Fuel Sulphur Content Reduction
The regulation of sulphur oxides (SOx) emission from ships has resulted in legislation that demands a reduction of fuel sulphur content in marine bunker fuel and also the uptake of SOx reducing technology. Ships sailing in SOx Emission Control Areas (ECAs) or ships that come under the jurisdiction of the global sulphur cap, both of which are governed by the International Maritime Organization (IMO), must use bunker fuel that meets sulphur content requirements or install exhaust gas cleaning technology.
When considering cylinder oil lubrication suitability for ships using low sulphur fuels, matching the lubricant’s base number (BN) (which, by way of a simple description, represents the quantity of alkalinity required to neutralise the acidity of the fuel) to the sulphur content of the fuel to avoid engine wear and cylinder liner corrosion is paramount.
When using a low sulphur fuel, a low BN lubricant should be selected. If a high BN lubricant is used, loss of oil control and the oil lubricant between the piston rings and liner can result causing metal to metal contact and adhesive wear.
Fuel switching is a practice that is becoming increasingly common for ships sailing in and out of ECAs. Managing cylinder oil lubrication during the process of fuel switching requires much consideration as it requires the use of different cylinder oil lubricants that are matched to the different fuels being used.
Also, the use of liquefied natural gas (LNG) as bunker fuel is becoming an increasingly popular option that ensures regulatory compliance but also brings cylinder oil lubrication challenges of its own. This fuel does not contain sulphur and the choice of lubricant is very much dependent on the percentage of gas that is burned in the engine. The impact of regulatory requirements that drive the reduction of sulphur content in fuel may be influencing the optimal selection of cylinder oil lubricants right now, but the complexity of choosing an all-encompassing, future proofing cylinder oil is set to continue.
Future ECA designations, such as the 0.5% global sulphur cap and the Pearl River Delta, the Yangtze River Delta and the Bohai Bay waters and the implementation of the lowered fuel sulphur content restrictions under the global sulphur cap in 2020 or 2025 will demand that more ships change their preferred fuel type or engines forcing them to review their choice of cylinder oil lubricant.
However, ship operators must not fear the regulatory landscape ahead when choosing their cylinder oil lubricants. Lubricant manufacturers are always at hand to advise on the selection of suitable cylinder oils to ensure the process of future proofing ships for prime ship performance under changing conditions or requirements.
Fathom-News
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