A novel designation of LNG solid oxide fuel cells combined system for marine application

Abstract

This paper presents a pioneering multigeneration system for marine vessel applications, involving the integration of solid oxide fuel cells (SOFCs) fueled by liquefied natural gas (LNG), coupled with LNG cold energy utilization cycles and exhaust gas heat recovery systems. The system comprises a tandem arrangement of organic Rankine cycle (ORC) and trans-critical carbon dioxide cycle (TCO2), specifically engineered to harness the cold energy released during LNG regasification process. The elevated temperature exhaust gases emanating from the SOFC are efficiently recuperated through a series of components including a gas turbine (GT), regenerative, steam Rankine cycle (SRC), and waste heat boiler (WHB). The proton exchange membrane fuel cells (PEMFC) is designed to enhance the overall operational flexibility and responsiveness of the multigeneration system. The Aspen Hysys V12.1 is used to simulate the propose system and numerical method is employed to parameter optimize of system. The first and second laws of thermodynamics are applied to establish the thermodynamics equations and calculated the system performances. The described system is estimated to obtain energy efficiency of 69.32 % and exergy efficiency of 33.85 %. The high-temperature exhaust gas harvesting integrated systems are sufficiently generated 2091.24 kW which accounted 35.49 % of entire power generate. Furthermore, the parametric researches are implemented to examine the influence of current density, β values to the performance indicators of systems. The WHB is designed to generate 1081 kg/h of superheated vapor at 170 °C and 405 kPa for various purposes of seafarers and equipment's onboard ship. The economic feasibility is performed to view the possibility of investment, maintenance cost and payback period for the described system.

Keywords

• LNG
• SOFC
• PEMFC
• Rankine cycles
• Waste heat recovery
• LNG cold energy