Prepare fuel tanks now to meet IMO 2020, says Intertek’s technical manager

Prepare fuel tanks now to meet IMO 2020, says Intertek’s technical manager

While countdown to IMO 2020 is well under way, there are still concerns around the quality and stability of compliant 0.5 per cent sulphur fuel blends. Uncertainty is exacerbated by the current lack of compliant fuel blends. Global technical manager at Intertek, Michael Green, says that it is unlikely that a clear direction will be found until such fuel blends have been operating in the market for several months. He urges shipowners and operators to prepare their fuel management systems now to reduce contamination, incompatibility, and operational issues.  

To prepare for bunkering new fuels, shipowners and operators must ensure that their ships’ tanks are fully cleaned and free from any traces of non-compliant fuel. If a new 0.5 per cent fuel blend is contaminated with remnants of HFO, a shipowner could find itself inadvertently not complying with IMO 2020. Furthermore, the contamination could lead to fuel instability and a clogging of the filters and separators with sludge.

Exacerbating this issue is the fact that each 0.5 per cent fuel blend will come from multiple refinery streams, meaning that a 0.5 per cent sulphur fuel bunkered at one port will be of a different chemical composition to a 0.5 per cent sulphur fuel bunkered at another port. There is some concern that bunkering various blends will result in incompatible and unstable fuels being used onboard.

During a webinar held by Intertek this week, global technical manager at Intertek Michael Green said that while some fuel suppliers are offering reassurance regarding compatibility for their products to reduce uncertainty, the current lack of available 0.5 per cent fuel blends means that the industry cannot be certain as to what will happen in 2020. Referring to the IMO’s 0.1 per cent sulphur cap that was enforced in 2015 in designated Emission Control Areas (ECAs), Mr Green said that many issues that weren’t predicted only came to light several months later. He expects the same thing to happen with the 2020 sulphur limit. “What we have seen so far suggests that compatibility will throw up a few curve balls,” he said. However, there are some lessons learned from 2015 that can help shipping to prepare for these curve balls.

One of the lessons learned from 2015 is that the risks associated with incompatible fuels can be reduced by ensuring proper storage and fuel segregation systems are in place. “Right now, owners and operators should be preparing their vessels to make sure they don’t contaminate the new fuel,” said Mr Green. This involves thoroughly cleaning the vessel’s tank to prepare for new fuels, which typically is part of the planned maintenance schedule.

There are several aspects to consider when planning for tank cleaning. Some of these highlighted by Mr Green include:

The size, geometry, and structure of the tank. “It is not as simple as saying we are going to clean the tank and flush it with X,Y,Z and we get a clean tank as there are intrusions, heating coils, and a variety of things that have to be considered and taken into the preparation process to ensure the tank is cleaned as thoroughly as it can be.”

The current state of the tank. This includes its cleanliness and condition at this moment in time. “This also depends on the type of fuel used previously in the tank. If you had a tank used with high sulphur fuel, there may be residual and metal content sitting in the sludge so you think about how to remove it as efficiently as possible.”

The quality of fuel used previously in the tank. “This plays a key part. There are lots key factors to think about rather than just saying you can flush the tank and that’s it.”

In addition, different fuel types should be well segregated due to the current uncertainty and lack of clarity around fuel availability.

Options for tank cleaning

There are several options for tank cleaning, but whichever option is chosen should be carried out now to ensure a gradual process of cleaning. This is likely to produce the best results. “When you’re in position at the end of this year to bunker new 0.5 per cent fuels you need to be in a position to do so,” Mr Green warned.

Options for cleaning include manual cleaning during dry-dock or in-service, which “is a time-consuming and expensive process but if pre-planned could offer a good route to prepare for new fuel,” said Mr Green. Additive treatments can also be applied but these are typically done over several bunker cycles to reduce the risk of sludge formation. “This tends to be part of a planned maintenance agreement and therefore companies should probably be doing it now.”

Another method is tank flushing. This can be done with either very low sulphur fuel oil (VLSFO) or marine gas oil (MGO). With MGO, the sulphur properties of sulphur can be strong, warned Mr Green, so companies may need to do this in a controlled manner to ensure low impact to the fuel injection system.

Flushing with VSLFO is something Intertek has seen a lot of over the last few months, Mr Green confirmed. “It’s a relatively simple process and it adds to the experience of using VLSFO.”

However, recent case studies carried out by Intertek further highlight the importance of allowing enough time to clean the tank fully. In one scenario, Intertek used VSLFO to flush a tank, starting with a 0.8 per cent sulphur fuel that was loaded into the clean tank. The consumption of fuel and sulphur content was monitored with samples taken at regular intervals to monitor the drop-in sulphur content in the tank. As indicated in figure 1, there was a steady drop in sulphur content from 0.8 per cent to 0.5 per cent but even after 38 hours of flushing, the level of sulphur in the tank remained at 0.51 per cent, above levels permitted by the IMO. “The key takeaway here is that there is a drop, but a single flush at this point has not been sufficient to ensure compliance to 0.5 per cent.”

Case study 1. After 38 hours of flushing, the level of sulphur in the tank remains at 0.51 per cent, above levels permitted by the IMO. Figure courtesy of Intertek

In a second case study, the tank flushing was done with a fuel containing 1.82 per cent sulphur. As seen in figure 2, there is an immediate and rapid drop in the sulphur level in the tank, but it takes over 90 hours for the level to drop anywhere near to IMO compliance levels. After 96 hours, the sulphur level is still at 0.51 per cent, once again higher than IMO will allow from January 1, 2020.

Case study 2. After 96 hours of flushing, the sulphur content in the fuel reads 0.51 per cent. Figure courtesy of Intertek

“This really reinforces need to potentially have multiple tank flushing treatments if using a VLSFO,” Mr Green emphasised.

Prioritising 2020 questions

Despite the short time frame until IMO 2020 is enforced, Mr Green said he still hears questions about which fuels are available, where they can be bought from and whether shipping companies should invest in scrubbers at this point in time.  He believes that while there are still many unanswered questions, the industry must think about what questions are relevant at this time, and what are not.

Mr Green says that it is “frightening that some people are still asking if 2020 will be deferred.” He admitted that he still has companies asking Intertek about action plans and when they should start implementing procedures for 2020. “It could be really tricky if they are only asking now.”