Graphical approach for estimating and minimizing boil-off gas and compression energy consumption in LNG regasification terminals

Abstract

Liquefied natural gas regasification terminal operations are energy-intensive where compression of boil-off-gas consumes most of the energy. Improving such a terminal's economic performance demands effective boil-off-gas management that depends on its accurate and early prediction. Boil-off-gas processing and management systems are available, but they tend to incorporate boil-off-gas estimations that are either in the context of computationally expensive models or involve full-scale dynamic simulation models that require process data and expertise. To simplify boil-off-gas estimation, this study proposes a generalized graph that provides a correct estimation of boil-off-gas and the minimum compression power required to handle that estimated quantity of boil-off-gas generated. The method can be applied to a wide range of the liquefied natural gas regasification terminals currently in operation. This graphical approach renders the estimates of boil-off-gas generated and associated compression energy requirements without recourse to simulation. It can also provide early estimates of a terminal's energy requirements before any detailed analysis.