Dynamic Study of LNG Fuel Gas Supply Systems

Abstract

Liquefied natural gas (LNG) is an alternative fuel which is gaining popularity in the marine sector due to tougher emission regulations coming into effect in the year 2020. Due to the increased demand of marine LNG fuel, new larger scale gas supply systems are being developed. In this report, dynamic simulations of two new marine LNG fuel gas supply systems have been developed in HYSYS to study the control, buffer capacity and characteristics of the new systems. The evaluation has mainly been made by simulating various critical scenarios, such as emergency loadup, emergency shutdown, compressor start and low operating pressure. A control strategy has been made for the pumps and the compressor but not for the minimum flow line. Findings from the simulations show that the control strategy is able to handle most system changes without disruptions to the engines. It was also observed that the use of a buffer vessel alleviated disturbances but it was not deemed to be a necessity in a well tuned system.