Exergoeconomic and exergoenvironmental analyses of a potential marine engine powered by eco-friendly fuel blends with hydrogen

Abstract

Maritime vessels have increased in size to facilitate the transportation of more goods and fuels between continents, but these huge ships rely on diesel engines and consume more fossil fuels that negatively affect the environment. A potential strategy is to replace traditional fuels with clean and green choices and upgrade engine performance. This research paper introduces a newly developed hybrid integrated marine engine involving a gas turbine, a solid oxide fuel cell, and two organic Rankine cycles. This potential engine is then analyzed using exergy, exergoeconomic, and exergoenvironmental analyses and assessments. It is found that the engine combination can produce 15.8 MW, which is increased by 50% compared to a traditional marine engine, and the engine performance reaches 38% energetic efficiency and 47% exergetic efficiency. Also, the exergetic efficiency based on the fuel and product principle is 54 %. This engine has a 243 $/h levelized cost rate and a 132 mPt/h environmental rate. Finally, the average overall specific product exergetic cost and specifc product-based environmental impact are obtained to be 60 $/GJ and 20 mPt/MJ, respectively. By comparing five potential fuel blends (namely MF1 with 25% hydrogen and 75% methane, MF2: 25% hydrogen and 75% methanol, MF3: 40% hydrogen and 60 % ethanol, MF4: 40% hydrogen and 60% DME, and MF5: 40% hydrogen, 15% methanol, 15% methane, 15% DME and 15% ethanol), the blend of methane and hydrogen with marine fuel (MF1) is found to be the most economical with the lowest environmental impact while the second option is the ethanol and hydrogen blend (e.g., MF3).