Development of Dynamic Process Simulator on LNG Vessel Gas Management System

In the Asia Pacific region, LNG is transported by ocean on vessels with cryogenic tanks. A significant fraction of the cargo LNG volume evaporates during voyage as Boil-off gas (BOG). To minimize loss, the control system attempts to match the BOG with the vapor demand for operating the vessel.

The authors have combined a dynamic simulation in a commercial process simulator with empirical models of the process and advanced process control (APC) within a DCS system. The dynamic process model consists of Gas Management System (GMS) to handle BOG, with a detailed boil-off gas model from LNG tank. The simulator will be utilized for not only control design, but also the system test for DCS function validation through OPC.