Fuzzy risk analysis of molten carbonate fuel cell propulsion system using boil-off gas in liquefied hydrogen tanker

Abstract

This dissertation proposed an MCFC (molten carbonate fuel cell) based system for a liquefied hydrogen tanker as prospective one including fuzzy-based risk analysis. The liquefied hydrogen tanker that is the new concept of a gas carrier transports cargo of liquefied hydrogen in bulk. This tanker uses hydrogen BOG (boil-off gas) as fuel according to the propulsion type. The MCFC based propulsion system that consumes the hydrogen BOG and natural gas generates electric power for ship propulsion. The exhaust at high temperature from the MCFC is recovered by a gas turbine cycle as indirect heating. A risk-based ship design should be considered for the MCFC and gas turbine hybrid system as non-conventional propulsion type. An FMEA (failure mode and effect analysis) technique is utilized for the hybrid system. Because the FMEA procedure has inherent uncertainty, the fuzzy logic is introduced to deal with the uncertainty. A fuzzy-based FMEA provides a flexible access to understand the risk picture of the hybrid system.