MEPC 280(70) decided, after the assessment of fuel oil availability that the fuel oil standard (0.50% m/m) shall become effective on 1 January 2020. This means that outside the special areas, ships should use low sulphur fuels (max. 0.5%S) or alternative fuels such as LNG, LPG, methanol etc., or use exhaust gas cleaning systems in combination with high sulphur fuels (as long that the systems meets the 0.5%S requirements.
At this moment the installation of exhaust gas cleaning systems, or retrofit of ships in order to use clean fuels is limited. This is of course due to the fact that shipowners don’t have an idea about the price gap between high and low sulphur fuels. That means that certainly in the beginning, the majority of the vessels will switch to low sulphur fuels.
As a result, the waste oil volumes will drop drastically in most ports. The reason for this phenomenon is clear: Deep-draught vessels generally burn low quality heavy fuel oil in their engines. This fuel contains contaminates. To prevent damage to engine components, retard wear, and improve combustion, the fuel is purified by centrifuges before entering the engines. At preset intervals, a shoot cycle occurs, which ejects contaminates (sludge), which drain to a sludge tank.
Compared with bilge water, fuel oil sludge is generally less varied and the quantities are more predictable, provided the quality of the fuel oil remains constant. As a general rule of thumb, approximately 1-2% of the heavy fuel oil burned in a vessel’s main engine and generators ends up as sludge. The quantity could vary depending on the fuel’s quality, its compatibility with previous shipboard fuels and the condition of the equipment used to store, transfer and heat it.
By replacing the heavy fuel oil by a low sulphur fuel, which has undergone a further refining process, only ca 0.5% of that fuel oil will end up in the sludge tank. As a result we can predict that waste oil volumes will drop with 50-60% after 01.01.2020.