Issues arose from Low Sulphur Fuel Oil adaptation
Issues arose from Low Sulphur Fuel Oil adaptation The introduction of the 0.50% IMO global sulphur cap on 1 January was always going to make 2020 challenging. As we entered this new era of environmental legislation, one of the big unknowns was the characteristics and market adaptation to the new compliant fuels. New blend proportions and feedstocks are formulated in order to create fuel mixtures that comply with the IMO’s new 0.5 % sulphur limit. And early experiences from shipowners suggest that the shipping industry has adapted well to the switch to the new very-low-sulphur fuel oil (VLSFO) products. But today we take a look at some of the issues such as Accelerated Engine Liner Wear, Flash alert, Poor stability, Short life span & varying viscosities that have arisen with the handling and use of VLSFO. Accelerated Engine Liner Wear The reduce sulphur content in fuels mean less acid being form during combustion. This has led to a change to cylinder lubricating oils with a lower base number (BN), which is a measure of the oil’s ability to neutralize acids from this combustion process. If the BN is too high, it can result in calcium compounds being deposited on the top of the piston crown. These hard deposits are abrasive and can cause liner wear, scuffing or piston ring breakage. Flash alert Surveyors have recently issued several bunker alerts where flashpoints have been below 60°C, which is below ISO8217:2017 standard. Some industry experts have questioned whether reduced car and aviation fuel usage during the COVID-19 pandemic has led to refineries pushing out more volatile blends made up from this lower-than-normal priced fuel. Varying viscosities VLSFO’s present in the market is of very different quality. All VLSFO complied with ISO 8217 and 0,5% sulphur limit but other specs such as residual quality scattered between RMA to RMK specifications. Poor stability & Short life span Many VLSFO products are blends of different components. If there is a mixture of aromatic and paraffinic blend components, it increases the risk of instability. Unstable fuel can cause sludge to form and the sludge in turn will block pipes, choke fuel filters and solidify in tanks. In extreme cases it will damage piston rings and fuel pumps. Dealing with the consequences of an unstable fuel often requires the crew to work long hours over several days to keep the vessel moving, carrying out labour-intensive and dirty tasks such as cleaning centrifugal separators and removing blockages. This is likely to lead to delays in the vessel’s schedule. In extreme cases, there have been losses in propulsion which is of course a big danger. The usual test for stability is Total Sediment Potential (TSP). This is carried out by fuel testing laboratories as part of the suite of tests for checking fuel quality against the parameters of ISO 8217. If the TSP is greater than 0.10% (by mass), then it is at higher risk of becoming unstable. Since VLSFO products hit the market, fuels are failing on high sediment levels more frequently. There are reported cases where the VLSFO product met ISO 8217 specification limits for TSP at time of bunkering and subsequently became unstable within a matter of weeks. The shelf life of some fuels has decreased significantly, which couldn’t come at a worse time when some operators are placing their vessels into lay-up because of the economic impact of the COVID-19 pandemic.