Marine Inventory-Routing Problem for Liquefied Natural Gas under Travel Time Uncertainty

In this paper modelling maritimeinventory-routing problem for liquefied natural gas (LNG) under uncertainty of travel time is presented. We consider one hypothetical LNG manufacturer in Iran that sells its products in the form of long-term contracts and spots. The purpose of the study is to examine and compare the shipping costs of split and non-split delivery.The objective function is minimizing the operational costs, contract penalties, and spot fees, and the main constraints are liquefaction port constraints, ship flows, customer and contractual constraints. Considering uncertainty in the problem is one of this paper's contributions which is modeled by assuming vessels speed as a fuzzy parameter. The parameter and related constraints are defuzifided by Jimenez approach and for solving this problem a metaheuristic method is applied and effectiveness of results are compared with a commercial solver. According to the computational results split delivery policy in deterministic problem is cost effective but in the uncertain situation it is more costly comparing to non-split delivery policy, so split delivery is not recommended in maritime transportation with uncertain nature.