Experts at Riviera Maritime Media’s Four-stroke lubrication options post-IMO 2020 webinar explained how lube oil chemistry and properties had changed to accommodate the industry’s trend towards low-emissions fuels
This event, supported by premier partner Gazpromneft Ocean and sponsor Lubmarine, was held on 8 June during Riviera’s Marine Lubricants Webinar Week.
On the panel were Caterpillar filters and fluids lifecycle manager Tim Styfhoorn, Lubmarine technical director Nikolaos Kotakis and The Viswa Group chief executive and founder Ram Vis.
After the introduction of IMO’s 2020 sulphur cap regulations, most of the world’s ships with two-stroke engines transferred from using heavy fuel oil (HFO) to very low sulphur fuel oil (VLSFO), changing the requirements for lubricant properties in engines. Ships with four-stroke engines run on distillates, but an increasing number of vessels are using gas fuels. This leads to the need for lubricants with different additive, chemistry and oil properties.
Dr Vis said around 61% of ships worldwide use VLSFO, 31% use distillates and just 8% have HFO plus emissions abatement technology. This has led to lubricant suppliers developing additive packages for different fuel and base oil groups, and a greater need for testing the compatibility of the same lube oils from two different manufacturers.
Viswa developed a proprietary index (TLW) to assess the performance properties between lube oils of the same type and compute the difference in monetary terms.
“We performed a benchmarking study for a major vessel operator who was using lube oils from two main brands,” Dr Vis explained, although he did not name the brands or suppliers.
“The performance of the oils was measured and validated in monetary terms using the TLW Index,” he said. “The study compared main engine crankcase oil, auxiliary engine crankcase oil and cylinder lube oil.”
These oils were evaluated based on energy efficiency, volatility, oxidation stability, ability to release water and entrained air.
“Using facts and real-time data from vessel operators, our index independently assesses these performance properties of the new lube oils and validates them,” said Dr Vis.
For example, a main engine crankcase oil of brand A achieved a TLW index score of 60.61, while brand B achieved a score of 56.75. The difference between these two scores comes to 3.86. The TLW index then converts this to an equivalent dollar value.
Mr Kotakis said the three main reasons for selecting marine lubricants are the original equipment manufacturer (OEM) products they will be lubricating, the type of fuels used, and the trade ships are expected to complete.
Lubricants need to be “matched to the most severe conditions” and “the emissions requirements where ships will be operating,” said Mr Kotakis.
Fuels could include HFO, VLSFO, distillates or pure gas. Lubmarine’s product for HFO and scrubbers is Aurelia TI with base oil numbers (BN) 30, 40 and 55. For VLSFO it recommends Aurelia BN 20-30, distillates using Disola M (BN 12-15) and for gas engines Lubmarine supplies Aurelia LNG lubricant oil.
More products are coming as shipping companies are driven to reduce the carbon intensity of their operations.
“We will have to deal with reducing CO2 emissions,” Mr Kotakis said. “Lubricants can help by offering fuel economy.” This includes changes to detergents, dispersant and antiwear additives and, in Aurelia Fuel ECO, a friction modifier.
Mr Kotakis said this was not yet approved by OEMs, but was being tested on ships including on a ropax ferry, which has demonstrated 4.7% fuel economy during trials.
To ensure appropriate lubricant condition and performance in the long term, Lubmarine uses monitoring services including onboard test kits, full laboratory analysis schemes, comprehensive analysis and technical expertise.
Mr Styfhoorn explained the importance of designing filters and fluids to maximise performance, extend maintenance intervals and reduce the total cost of ownership (TCO) for engine systems and auxiliaries. “Filters and fluids are designed to work together as a system to optimise engines and reduce equipment downtime,” he said.
Caterpillar designed its lubricants for enhanced sheer stability, superior oxidation stability, improved oil oxidation and better viscosity control at higher temperatures through development and testing.
Mr Styfhoorn said Cat filters have polyurethane end caps, acrylic beads for keeping the high-grade media spaced and a nylon-reinforced central tube, which is stronger than metal and has no metal shavings in the filter that could cause component damage. It also has spiral roving holding the entire filter in place, which reduces particles getting through to machinery by 45%.
Caterpillar has developed its lubricants through 50 years of fluid analysis. This has “helped prevent unexpected failures and unplanned downtime while reducing owning and operating costs,” said Mr Styfhoorn.
Its SOS analysis service assesses whether the product is at risk of potential failure, provides advice on actions needed and replacement parts. “We offer fluid analysis for all types of products, whether they are made by Caterpillar or another OEM,” said Mr Styfhoorn.
Attendees of the webinar provided a rich seam of data for analysis through a series of poll questions. They agreed the importance of TCO, especially the period between oil changes in their selection of lube oils. When asked how important is extending or optimising oil drain intervals for ship engines or systems, 25% said it was their highest priority and 61% thought it was important, while 11% said it was of routine importance but no more, and just 3% voted for ‘not even on the radar’.
In another poll, delegates were asked how often they employ lubricant analysis or related technical services to monitor the performance of a four-stroke marine engine lubricant.
39% said they perform lubricant analyses in line with the minimum requirements from the OEM or class, 36% said they have proactively set a denser analysis interval, of more frequently than the minimum. 14% of the respondents said they perform lubricant analyses only when issues arise and/or at irregular intervals and 11% said they do not monitor the lubricant at all.
When questioned whether they select lube oil based on performance properties such as lubricity and volatility or just based on price, 59% voted it was based on performance and 41% on price alone.
Attendees were also asked what group of base oil they currently use for their generator crankcase, with 59% voting for G2, another 30% for G1, none for G3, but 11% for synthetics.
In another poll question, delegates were asked for their view on why the range of oil with TBN 20-40 was used in auxiliary engines using VLSFO while it is about 20 BN for engines using HFO.
64% of respondents said it was because VLSFO fuels have a wide range of properties and come from aromatic and paraffinic sources, 25% thought it was because of new formulations of lube oil for VLSFO fuel and 11% said it was because engine makers were asking for it.