DNV GL Warns on Potential for LNG Bunker Quality Issues Leading to "Engine Damage and Failure"

by Ship & Bunker News Team
Wednesday November 16, 2016

If the quality of liquefied natural gas (LNG) bunkers is not correctly matched with an engine's requirements, it can result in engine damage and even failure, DNV GL warned Tuesday.

"As LNG is produced at different locations around the world, using an assortment of production technologies, its composition can vary considerably. Determining its fitness-for-purpose can be difficult and the consequences of mismatching fuel quality to a specific ship engine can cause potentially dangerous effects such as significant loss of performance, engine shutdown and even damage," said Liv Hovem, DNV GL's Senior Vice President, Oil & Gas.

"Knowledge of the knock characteristics of LNG fuels is therefore crucial for suppliers and traders to provide reliable and efficient products and to break down the perceived barriers of adopting LNG."

The comments came alongside news that the company has developed a new tool, the PKI Methane Number Calculator, to help users of LNG bunkers mitigate such risks.

"Engine knock is characterized by auto-ignition of the unburned fuel mixture, known as the end gas, ahead of the propagating flame in the engine cylinder," DNV GL explained.

"DNV GL has developed a verified algorithm to quantify the effect of LNG quality on engine knock, and thus to help LNG users ensure safe and efficient engine operations."

The knock resistance of LNG is characterized by a methane number, which DNV GL says can be considered to be similar to the octane number used in gasoline engines.

"Users of the tool simply enter LNG composition information such as nitrogen, methane, ethane, propane, and n-butane, and the tool calculates a PKI methane number, which can be matched with the engine specification," the company said.

Johan Knijp, Head of Gas Quality and Energy Transition, DNV GL – Oil & Gas, added: "DNV GL's PKI Methane Number Calculator applies a generic method to quantify the knock resistance of LNG. The methodology behind the knock characterization calculator has been developed with an eye towards serving as the basis for a robust standard."

Further details of the tool can be found here: https://www.dnvgl.com/oilgas/natural-gas/fitness-for-purpose-of-lng-pki-methane-number-calculator.html