MFT

Adjusting the concentration of cylinder oil BN and additives

The main purposes of cylinder lubrication is to build an optimal oil film for piston running, neutralising sulphuric acid from fuel combustion, and cleaning. A technically and commercially favourable alternative to the traditional measures is to maintain the cylinder oil feed rate at the most optimal level, under almost all operational conditions, while, simultaneously, adjusting the cylinder oil’s properties to the actual conditions. This is exactly what is achieved with the BOB concept. The concept is to keep the cylinder oil feed rate constantly low, while adjusting the concentration of the additives in the oil. This results in a wide base number range, from 40BN to 120BN.

“The Blending-on-Board solution was attractive, as the system addresses the need to adjust the lubrication oil, according to the changing situation, including the engine load, fuel and environmental conditions”, says Ralf Veigel.

Scope of Supply

The unit was ordered through Wärtsilä in Germany, and the scope of supply included the delivery and installation of the BOB system SEA-Mate^® Blender, consisting of a blender with a blender control panel. Installation of the system was relatively simple and was be done without interrupting the vessel’s commercial operations. The pre-inspection of the engine system took place in Singapore and the installation of the system was performed in South Korea in December 2013.

The solution has been designed in a modular way, in order to allow easy installation, and is compact enough to be placed in the engine room.

“The time between pre-inspection and the installation was less than six weeks. The installation, including piping and necessary tank adaptations, could be carried out during a port stay of the vessel, which is quite an achievement. Thanks to the close cooperation between Wallem and Wärtsilä, the challenges, such as the short time, the organisation and transportation of the goods, did not affect the installation work”, states Ralf Veigel.

Reduced cost for lubrication and engine maintenance

With a BOB installation, the in-use system oil is transferred from the main engine, and, optionally, also the auxiliary engines, and is then blended with a specially formulated cylinder oil additive. The result is cylinder oil for the specific operating conditions of each vessel, thus reducing a vessel’s lube oil consumption by 10%-50%, depending on the currently used feed rate.

To reduce corrosion, Wärtsilä and other engine designers recommend increasing the cylinder lubrication oil feed rate or the use of different lubrication oils. However, with the BOB equipment in use on a vessel, the reduction in corrosion can be achieved by adjusting the BN of the lubricant, and not by increasing the cylinder oil feed rate. Wallem’s experience with the BOB solution has been very positive, so far.

“We have been able to optimise the lubrication, reduce the feed rate and stabilise the piston running, says Ralf Veigel and continues to highlight the benefits that Wallem has gained through this installation: – We have optimised the piston running, achieved flexibility and, most importantly, reduced the costs concerning lubrication”.

Valuable technical support

Mr. Veigel says that Wärtsilä has been supporting his team throughout the installation and also when using the system. He points out that there has been a mutual exchange of open and trustworthy information already before the installation, which supports Wallem’s aim to reduce the lubrication costs.

“Part of this successful product is a close cooperation with Wärtsilä and having a fast and direct contact to their technical know-how. This is, especially, relevant for newly introduced products. If a ship operator requires flexibility and runs the engine at low loads with different fuel qualities, I would, without doubt, recommend installation of the Blending-on-Board system”, concludes Ralf Veigel.​