عنوان مقاله [English]
In this research, distribution network of petroleum products in operational level is investigated. This network consists of transportation roads as well as pipelines. Based on the assumptions and limitations of the network, there are time windows for distribution time of products, demands, and transportation routes. The aim of this research is to propose a time plan for transportation of petroleum products which consists of a transportation schedule for each product including the volume of product, type of vehicle, and transportation route. The objective is to maximize demand coverage as well as to minimize total transportation costs. The components of the network under investigation are refineries, major storages, power plants, gas stations, minor storages, and customers. Petroleum products can be transported through all roads by different types of trucks (if the road is available for that type of truck during transportation time). Moreover, petroleum products can be transported to minor storages, power plants, and gas stations directly from refineries or through major storages. According to the fact that different trucks with different capacities are used for transportation, some roads are not available for specific types of trucks. Additionally, some roads may be unavailable for some or all types of trucks in specific time periods. In order to provide a mathematical framework for this problem, the problem is formulated as a mixed integer linear programming model. In the proposed model, a variety of real-world assumptions have been considered. According to the high complexity of the problem, a multi-objective metaheuristic algorithm, namely NSGAII, is then applied to provide solutions in a reasonable amount of time. In the proposed algorithm, special mechanisms have been used to enhance its efficiency. These mechanisms include a procedure for initial solution generation and another for maintaining feasibility of solutions when they undergo different operators. Finally, the proposed algorithm has been applied to solve the problem of transportation planning in petroleum products distribution network of Kurdistan province. Results reveal that the proposed algorithm is efficient.