Advice could help marine operators and shipowners to avoid potential maintenance issues
By
Rebecca Gibson |
International oil and gas company ExxonMobile has shared five tips to help ship operators avoid maintenance and operational issues when switching fuels upon entering and exiting Emission Control Areas (ECAs).
According to ExxonMobil, inadequate management of the fuel switchover process can increase the risk of thermal shock to engine components, leading to fuel pump seizures and engine shutdowns. To mitigate these risks, the company advises that ship operators consider the five following tips:
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Have a clear switchover procedure – crew should be familiar with the processes, which should all have been tested prior to the vessel entering crowded and restricted channels where there is a higher risk of grounding or collision.
- Outline the best time to switchover – the optimal switchover period is different for each vessel and operators must allow sufficient time for the fuel system to be flushed of all non-compliant fuel before arriving at an ECA limit.
- Know the correct temperature and viscosity – the viscosity of heavy fuel oil (HFO), ECA fuels and marine gas oil (MGO) are different and it is important to ensure that the fuel reaches the optimum viscosity at the injectors. HFO is injected at ~130°C and MGO needs to be cooled to ~30°C in order to reach the correct viscosity. Major engine manufacturers typically recommend a maximum temperature change of 2°C per minute to help avoid thermal shock.
- Understand compatibility – there is a potential risk of fuel incompatibility during the switching process where fuels may mix, which could clog filters and possibly engine shutdown. To identify whether fuels are compatible, shipowners can carry out an onboard industry-standard spot test, or request a more thorough compatibility test from a reputable testing laboratory.
- Choose the correct lubricant – cylinder oils need to be sufficiently alkaline to neutralise any corrosive acidic sulphur in the fuel. However, too much alkalinity in the cylinder oil can lead to liner wear, while too little increases the risk of acid corrosion. When burning low-sulphur fuels in slow-speed engines, shipowners should use a lower base number lubricant.