Recent restrictions on Sulfur Oxides emissions in ships are to be enforced by 2020. The IMO – International Marine Organization – has decided on limiting the maximum amount allowed to 0,5%, a cap that has already been established in Europe and the Americas but still needs to be applied worldwide. Tens of thousands of ships are affected and the time to comply is short.
The choices available to comply with the new IMO regulations are to either adapt the ship in order to limit the emission (installing scrubbers – exhaust cleaning systems or retrofitting vessels to use alternative fuel types such as LNG) or change the used fuel (using either MGO – marine gas oil or distillates or switching to a new low-sulfur and compliant fuel blends). The first possibility involves a costly investment of millions of dollars with the requirement of ship adaptability to integrate complicated systems.
Using new types of blends is easy to implement as the fuel can be used with most engine configurations. The question remains to either use distillate fuel of higher cost with possible usage issues due to low viscosity or change to a previously untracked fuel type that may be a source of incompatibilities.
A new type of fuel is regarded to be available by the end of 2018 with an expected 15% lower cost compared to distillate fuel. However, “it is very likely that the new fuel blends will face compatibility problems, which will make fuel handling very important for safe operation. Other concerns regarding these fuels include long-term stability, the potential for catalyst fines, and their flashpoint.” 
New blends developed to reach low sulfur requirements may be issued either from desulfurization or simply new formulas. The interest in the new type of blend leans toward higher-grade fuels instead of using desulfurization plants since the capacity to provide low sulfur fuels is overwhelmed by the demand. But in both cases, the changes in additive concentration or nature may impact the overall chemistry of the blend and thus its stability. A fuel blend vulnerable to ship storage conditions is a risk to the engine as it may lead to combustion problems and eventually block the engine immobilizing the ship. This requires further investigation regarding the optimization of additives such as antifouling agents, asphaltenes inhibitors, etc. The need arises to develop new methods and standards for the new fuel blends and the ISO group is already looking for technologies capable to perform long-term stability testing of new maritime fuel blends. But the solution may not be available before 2022 – 2 years after the Sulfur Cap becomes effective.
Turbiscan Oil Series has already been recognized and used to monitor the asphaltene stability of heavy fuel oils and prevent plugging while handling the oil and fouling while cruising on open seas. Turbiscan Oil Series along with the ASTM D7061-12 provide methodology and metrics to quickly rank the stability of blends, select the correct dispersant/chemical, and fine-tune the concentration to ensure the best performance without taking any risk regarding asphaltene stability. The measurement only takes 15 minutes and automatically generates the Separability Number (SN) related to the asphaltene stability. A low SN will mean a good stability reserve of the oil while a high number (>10) will mean a poor stability reserve.
This makes Turbiscan the perfect tool for the characterization of new marine fuel blends in terms of stability. More than 2000 laboratories use Turbiscan instruments to measure and quantify the stability of different types of emulsions and suspensions.
DNV-GL; Global Sulphur Cap 2020; 08/2018