Ahead of the IMO global sulphur cap, entering into force in 2020 and expected to dramatically change the fuel landscape in the maritime industry, American oil major ExxonMobil has published best practice tips to help operators switch to low sulphur fuels, while maintaining a vessel’s safe and reliable operation.
The 2020 sulphur cap, set by IMO, mandates ships to operate with fuel not exceeding the 0.5% limit in sulphur content, from 1 January 2020.
First, establish best practice
Prevention is always better than cure, so it is advisable to:
- Buy fuel that meets the latest ISO 8217:2017 specification
- Only bunker from reputable fuel suppliers
- Clean out bunker tank residues when necessary
Test for cat fines
Some new 0.5 per cent sulphur fuels could contain elevated levels of cat fines which, if not properly treated, could trigger catastrophic engine damage. If laboratory testing shows a high concentration, then:
- Maintain storage tank temperatures at least 10°C above fuel pour point
- Keep settling tanks at 85°C
- Operate purifiers at optimum efficiency and minimum throughput
- Drain water from fuel tanks to aid settling
Check for compatibility
There is a risk that two compliant fuels will not be compatible, which can trigger sludge formation. It is therefore essential to:
- Test the fuels for compatibility, ideally in a laboratory. If the fuel is already loaded, then test onboard to get immediate results
- Store fuels separately until testing has been carried out
- Even when two fuels are compatible, avoid mixing in excess of 80:20
Monitor for sludge
If sludge does start to form, it is essential to ensure against further fuel blending before any remedial action is taken, as this may exacerbate the problem. Then:
- Operate two or more separators in parallel at their lowest throughput
- Increase the frequency of purifier discharge
- Monitor and clean filters frequently
John LaRese, Marine Fuels Technical Advisor, ExxonMobil, said:
With so many different types of fuel potentially set to enter the bunker market, vessel operators are rightly concerned about stability, compatibility and quality issues, such as elevated levels of cat fines. It will therefore be more important than ever for operators to follow best practice when bunkering compliant fuels, including using laboratories to test fuel samples for potential issues.
