Americas News
DNVPS: Kulluk Tug "Slime" Could Have Been Bacteria, Not Fuel Additive
Hauk Larsen Wahl, Regional Manager at DNV Petroleum Services Inc (DNVPS) in charge of North American operations, has speculated that bacteria in biofuel, rather than a fuel additive, could be to blame for the "slime" said to have shut down the engines of the tug Aiviq before the grounding of the Kulluk drilling rig in Alaska in late December.
Ship & Bunker reported last month that ship engineer Carl Broekhuis said samples of the diesel fuel showed a "clear, yellowish gel," which led to the failure of fuel injectors, though it is unclear what the additive was.
"All four engines onboard the vessel have ceased, and the chief engineer made some statements that appeared in the media about the fuel turning into, almost like jelly fish," Wahl told delegates at the GreenTech 2013 conference in Vancouver last week, who clarified that he had not seem the fuel sample himself.
"Eventually they had to fly out a coastguard helicopter to replace all the injectors."
"We think that its more likely that this is a FAME [Fatty acid methyl esters], biodiesel issue causing bacterial growth, and the bacteria causing slime, blocking filters, leading to fuel starvation."
Discussing the merits of FAME, or biofuel, Wahl said: "Bio Diesel is a great fuel, and in many countries it is mixed in with fossil fuels in blends.
"In the U.S. we see up to 5 percent bio-products in distillate fuel. Its a great fuel in terms of combustion. Its a great fuel in terms of lubricity."
However the downsides of bio-products, he said, was storage.
"If you store the bio-products for a long time you will have issues related to oxidation stability, and also potentially bacterial growth.
"Bacterial growth in fuels has actually been a problem that people know, and it is causing operational issues because this bacteria will eat the fuel - it will eat the fuel that you've paid for."
