Intertek: ULSFO Hybrid Fuels Burn Faster, Cleaner, and Have Good Net Calorific Values

by Ship & Bunker News Team
Wednesday April 8, 2015

Initial test investigations of the new generation of so-called "hybrid" fuels show they appear to burn faster and cleaner than their traditional fuel oil counterparts, while also having good net calorific values, test data from fuel testing agency Intertek ShipCare has shown.

However the test data also indicates that operators need to understand how to correctly store and use the products to avoid compatibility issues.

A number of companies are now selling such new generation fuels, which are also referred to by some suppliers as ultra low sulfur fuel oil (ULSFO) product, or Emissions Control Area (ECA) compliant heavy distillate.

Steve Bee, Global Business Director, Intertek (Lintec) ShipCare Services, who was speaking at last month's Connecticut Maritime Association (CMA) Shipping 2015 conference, presented the results of testing across four such fuels.

"We subjected the four hybrid samples to fuel ignition analysis (FIA) to see how the fuels would burn and compare these with the standard residual FIA," he said.

"Overall I think the speed of the hybrid fuel burn has been faster and cleaner and certainly with a sharp and clean after-burn period."

Vacuum Gas Oil

Bee explained that the hybrids tested showed varying degrees of similarity to low viscosity residual products, with densities ranging from 860 to 920 kg/m cubed, and viscosities ranging from about 8 to 50 cSt.

"The fuels tend to have a low metals content and are low in cat fines especially. But they do seem to exhibit higher pour points which would mean care in relation to the storage temperatures of the hybrids," he said.

It was also noted that while the majority of the hybrids Intertek ShipCare had tested so far met the requirements of an RMB30 or RMD80 grade of ISO 8217, the fuels were not actually residual products.

"Our advice to clients has been that they must be aware that there are no specific references within ISO 8217 to cover hybrids. The only information they receive regarding hybrid fuel quality will be form the suppliers themselves," he said.

"This may prove problematic if operational issues are noted and until ISO give guidance on hybrids, then shipowners and operators may be looking at fit-for-purpose as the only course of recourse available."

There was also a cautionary note on the storage and mixing of hybrid fuels.

"As we've stated a number of the hybrids have high pour points, and issues will be seen if the storage temperature is allowed to drop below that pour point. Given that the products really appear to be based on vacuum gas oils, the chances are that they're parafinic, and as such compatibility issues will probably be noted," said Bee.

"Certain manufacturers have stated that if compatibility issues are noted do not mix with more than 2% of residual product. But again, because of this hybrid, parafinic nature, there may also be problems when mixed with other distillate products."

In July last year ExxonMobil Marine Fuels & Lubricants launched its heavy distillate product, ExxonMobil Premium Heavy Distillate Marine ECA 50 (HDME 50), and last month introduced its second specialist fuel for use within ECAs, ExxonMobil Premium Advanced Fuel Marine ECA 200 (AFME 200).