Method and system for assisting the management of a liquefied gas transport ship of the type consuming evaporated gas for its propulsion

A system for assisting in managing a vessel for transporting liquefied gas, the vessel comprising at least one tank configured to contain the liquefied gas and a vapor phase treatment system, the vapor phase treatment system being capable of sending boil-off gas exiting the tank to a propulsion engine of the vessel and to a gas combustion unit on board the vessel, the system comprising:

• an acquisition unit configured to acquire an initial state of the tank and a forecast path of the vessel, said initial state of the tank comprising an initial pressure of a gas phase contained in the tank and an initial temperature of a liquid phase contained in the tank;
• a first communication unit configured to obtain weather forecasts from a weather forecast provider;
• and
• a computation unit configured to:
• on the basis of the weather forecasts obtained by the first communication unit, determine at least one environmental parameter of the vessel along said forecast path;
• determine a speed curve of the vessel along said forecast path;
• generate a tank management scenario defining an evolution in a pressure of the gas phase contained in the tank along said forecast path, and, on the basis of the tank management scenario thus generated, configured to:
• a) estimate a curve of an indicative quantity, the indicative quantity being indicative of an operation of the propulsion engine along said forecast path, as a function of said speed curve of the vessel and of said at least one environmental parameter;
• b) estimate a curve of an amount of the boil-off gas generated in the tank along said forecast path;
• c) estimate, on the basis of said curve of the indicative quantity and of said curve of the amount of the boil-off gas generated, a curve of an amount of the boil-off gas to be extracted from the vessel and a curve of an amount of the boil-off gas to be burned in the gas combustion unit;
• d) compute a cost function that at least depends on a total amount of the boil-off gas generated in the tank along said forecast path;
• and comprising
• a display unit configured to display to a user the tank management scenario.