Marine fuel quality trends and new low sulphur requirements

In the second in our two part series exploring the impact of ECAs fuel tester Veritas Petroluem Services (VPS) explains some of the issues and operational factors shipowners and managers will face come 1 January 2015.

When it comes to fuel quality trends, the end of 2014 is greatly influenced by the change in sulphur requirements for ships, without abatement technologies, such as scrubbers, onboard, operating in Emission Controlled Areas (ECAs).

From 1 January 2015, the MARPOL Annex VI requires that ships do not emit more SOx than if they burned fuel with a sulphur content of maximum 0.10 m/m%. Since only a small number of ships have installed scrubbers to date, allowing them to consume fuels with higher sulphur levels and scrub the exhaust of the SOx, the majority of the fleet needs to consume fuels with a significantly lower sulphur level compared to those currently used.

For a period, marine gas oil (MGO) and marine diesel fuels were seen as the only alternatives to residual heavy fuel oil fuels (HFO) when operating in ECAs post 1 January 2015, however, during the last half of 2014, new fuel products have entered the market. These new fuels all come from petroleum refining, a couple, however, are different from the traditional distillate and residual fuels. Whilst the way these new fuels will be priced is not clear yet, it is likely that they will be offered at prices below the MGO price which may make them attractive to operators, although their geographical availability is likely to be limited.

ISO8217, the most frequently used specification for fuel bunkers, was never made for these new products and comparing the information stated in the marketing material to the ISO8217 specification limits shows that the new fuels often fall in-between grades. Although some do, in general, they do not contain residue components but they do not meet the distillate grades either. vps

In addition to the commercial challenges of where to source the new products as well as which specification and grade to purchase these products to, there are the operational considerations. The ignition and combustion properties are generally good and the viscosity is higher than for distillates (eliminating the low viscosity challenges), but the cold flow properties need careful attention.

Typically, the pour point (PP) is high for these new products and more comparable to residual fuels (PP max 30°C according to ISO8217, Table 2) than to distillates (PP max -6°C for winter grades according to ISO8217, Table 1). Pour point is relevant for the storage temperatures. If stored at too low temperatures, the fuel may solidify completely due to the high wax content. Operators and purchasers should note that the heating capacity on a ship is inadequate to melt the wax once solidified.

Pour point represents the temperature at which the fuel stops flowing, i.e. turn solid. However, wax particles start to form in the fuel at temperatures above the pour point. The cloud point (CP) is the temperature where the formation of wax particles can be seen as a cloudy appearance. The cold filter plugging point (CFPP) is a filtration test carried out under laboratory conditions indicating the temperature where a reference filter blocks. The CP and the CFPP are useful for evaluating the risk of encountering filter clogging on-board due to the filters capturing the formed waxcrystals.

The PP and/or the CFPP can be suppressed by cold flow improvers whereas the CP cannot be changed by use of additives. Suppliers only focus on the PP in order to meet specifications because neither CP nor CFPP are included in the ISO8217 specification.

Hence, fuel purchasers are strongly advised to carefully consider seasons and operational pattern as well as specify the required cold flow properties (through CP and CFPP) when ordering new fuels and distillates. From an operational point of view, the crew should know the CP and CFPP of the products on-board in order to be able to take precautions to avoid filter blockages. The best and perhaps simplest way is to trace heat the filters, allowing the wax molecules to pass through the filters in their liquid form.

Another operational issue to carefully consider is compatibility between fuels during change over. Both distillates and the new fuels can be very paraffinic compared to the more aromatic composition of the HFOs. It is unavoidable that some mixing will take place in the fuel system during change over. In case of incompatibility between the fuels, asphaltenes will precipitate, causing sludge, and potentially blocking filters and pipes.

It is strongly recommended that the changeover point is as close to the engine as possible, preferably after the settling and service tanks, in order to reduce the amount of sludge in the system. If the changeover point is located before, e.g. the service tank, it should be run down as much as possible (class regulations regarding volumes required for consumption should also be considered) before the changeover takes place.

Although the industry will need to adjust to the challenges related to distillates and new fuels in the near future, the traditional HFOs will still be there for years to come. As the cheapest option for most marine engines, ships will continue to use HFO as long as the environmental legislations allow.

The abrasive cat fines are still present in HFOs and the overall global concentration has increased steadily over the years. In the period January to November 2014, Veritas Petroleum Services (VPS) issued 13 bunker alerts on high levels of cat fines for various ports. This is the highest number of cat fines related bunker alerts since 2008.

Another observation is that 10 bunker alerts (an all-time high) have been issued on sediments from January to November 2014. Sediments are an indication of the stability or amount of dirt in a fuel. The higher the sediments, the poorer the stability may be or the dirtier the fuel is. The high number of bunker alerts in this category may be an indication of new blend stocks being used in the fuel blends.

The full impact of the new sulphur limits is still unclear. It is uncertain to what extent the industry will embrace the new fuels or use the more traditional distillate products. It is also uncertain how prepared the industry is to cope with the challenges related to operation on max 0.10% sulphur fuels. Only one thing is certain – 2015 is likely to be a challenging year for the marine industry.
Source: Seatrade Global