BOG Recovery and Conversion into CNG Fuel at the LNG Receiving Terminal

This study addresses sustainable boil-off gas (BOG) management at liquefied natural gas (LNG) terminals, offering a solution to traditional methods like flaring and venting, which pose environmental risks. It proposes using excess BOG as fuel for compressed natural gas (CNG)-powered vehicles. Through simulations, BOG recovery during LNG regasification, ship unloading, and holding modes was quantified. Recovery rates varied by LNG type: 0.39% (lean), 0.338% (medium), and 0.337% (rich) during regasification; 0.27%, 0.2%, and 0.21% of offloaded LNG mass during ship unloading; and 0.028%, 0.026%, and 0.021% of the initial LNG mass in holding mode. Lean, medium, and rich LNG supported 361, 383, and 406 hours of regasification, respectively, at 200,000 kg/hour. Tanks reached 95% capacity in approximately 15.25 hours during unloading. Heat ingress, impacted by solar radiation and pump activity, caused significant heat leaks, mitigated by additional BOG storage tanks. Excess BOG, converted via a multistage compressor, produced CNG meeting conventional standards for lean and medium LNG, though rich LNG required blending. A 200,000 m³ LNG storage tank could fuel 35 to 489 vehicles with 25 kg storage capacity per hour. This innovative approach highlights BOG’s potential as a sustainable energy source, improving LNG terminal efficiency and reducing environmental harm.