A Study on the Improvement of LNGC Re-liquefaction System

Oh, Cheol.; Song, Young-Uk.

Journal of Navigation and Port Research 2009;33(10):659-664.
Published online December 30, 2009.

LNG선 재액화 시스템의 성능 개선에 관한 연구

오철, 송영욱

A Study on the Improvement of LNGC Re-liquefaction System

Cheol. Oh, Young-Uk. Song

Abstract

LNG carriers have, up to 2006, mainly been driven by steam turbines. The Boil-Off Gas from the LNG cargo tanks has so far been used as fuel. This is a costly solution that requires special skills during construction and operation. Alternative propulsion systems offer far better fuel economical efficiency than steam turbines. Instead of previous practice using Boil-Off Gas as a fuel, the Re-liquefaction system establishes a solution to liquefy the Boil-Off Gas and return the LNG to the cargo tanks. This Re-liquefaction of Boil-Off Gases on LNG carriers results in increased cargo deliveries and allows owners and operators to choose the most optimum propulsion system. In this study, thermodynamic cycle analysis has been performed on two type of LNG Re-liquefaction system which was designed and adopted for the Q-Flex(216,000㎥) and Q-Max(266,000㎥) LNG carrier under construction at Korea ship yards and variable key factor was simulated to compare efficiency, power and nitrogen consumption of each Re-liquefaction system.

Key Words: LNG;Boil Off Gas(BOG);Boil Off Rate(BOR);Re-Liquefaction system;COMPANDER;Q-Flex;Q-Max