Wrtsil LNG propertiesFuel consumption calculationRudolf WettsteinApplication DevelopmentMay 15, 2012Wrtsil Natural gas is mostly methane (CH4) Methane contains the highest amount of energy per unit of carbon of any fossil fuel Carbon to hydrogen ratio 1 / 4 (gasoline: 1 / 2,25) Lower CO2emissions Natural gas is: A very safe fuel Non-toxic Lighter than air What is natural gas?Methane (CH4)HHHHCEthane (C2H6)WrtsilLNG standard LNG composition: methane 85 - 99 % ethane +propane 1 - 15 % other 0 - 2 % Properties Condensing temperature -162 C(1,013 bar) Condensing heat 0,15 MWh/kg (-162 C) Density as liquid 430 - 480 kg/m3 (-162 C) Density as gas 0,75 - 0,85 kg/m3n (0 C / 1,013 bar) Lower heat value 9,8 - 10,5 kWh / m3n35280 - 37800 kJ/ m3n41500 - 50000 kJ/ kg(not included in standard)WrtsilFuel consumption calculationExampl e for 8L50DF medium-speed dual-fuel engineLNG fuel consumptionMCR- power 7800 kWat 514 rpmSpecific energy consumptionat MCR 7150 kJ /kWhSpecific heat rate of LNG 49000 kJ /kg (depending on gas composition)LNG density 460 kg/m3 (depending on gas composition)Daily consumption 7800 kWx 7150 kJ /kWhx 24 h / 49000 kJ /kg =27316 kg or 59.4 m3LNG fuel costAssumedprice of LNG 15 USD/mmBTU(dependingon country, seller, quanity, etc)1 mmBTU is 1,055,056 kJ 49000 kJ /kg x 15 USD/mmBTUx 1000 / 1055056 kJ=697 USD/ton