DNV GL Advises Caution on Hybrid ECA Fuel Switch

by Ship & Bunker News Team
Tuesday March 24, 2015

DNV GL has released a new technical update for its guide on Emission Control Area (ECA) compliance, advising shipowners to be careful when switching from heavy fuel oil (HFO) to ultra-low-sulfur "hybrid fuels."

The classification society said that hybrid fuels do not "necessarily fit into the traditional specifications for MGO, MDO or residual fuel oil (RFO)," since the fuel is a blended product with some specifications similar to HFO.

Though the fuels are ECA-compliant with a sulfur content of less than 0.10 percent, its viscosity, flash point, and aliphatic nature more closely resemble HFO.

"Based on previous experience, fuels with very different chemical compositions have a tendency to be incompatible when mixed in certain blending ratios," the company said. 

"All rules of thumb would indicate incompatibility between these types of fuel with the likely precipitation of sludge and clogging of the fuel/engine system as a result.'

DNV GL also pointed out that the fuels may also have a "cleaning effect" on storage tanks, which could cause loosened deposits to also clog filters. 

Overall, companies should carefully monitor fuel performance during the changeover process, in addition to starting the process well in advance of entering ECAs. 

Late last year, DNV GL released its initial sulfur compliance guide along with a Fuel Change-Over Calculator to help shipowners calculate the parameters for a ship's changeover process. 

Ship & Bunker News Team
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