Study On Base-Distribution Structure Model For Domestic Coastal Coal Shipment

This paper addresses the study of the Base-Distribution Structure Model for Domestic Coastal Coal Shipment.Due to the unbalance between the coal provenance and consumption in geography, a large quantity of coal needs to be transported within China. The coal transportation structure of west to east and north to south has been made, and which shipping structure model should be adopted is the basic decision to reduce the cost and increase the stability of coal shipment. Today, the Direct Shipping Model is usually employed in the coastal coal shipment in China:a ship is fully loaded in a north loading port, then sails to a south discharging port and is discharged empty. A Base-Distribution Model is proposed in this paper from the general interview of the whole coastal coal shipping system:the coal is shipped by big ships from north ports to a transshipping base in the south and discharged empty (Hub-Ship), then the coal is reshipped by smaller ships from the transshipping base to the final destination ports (Spoke-Ship).The problem discussed in this paper is an optimization of transportation system. The key issue is to choose the optimal size of ships to be used. The problem is formulated as a three-stage problem. First, a mathematic analysis method is employed to illustrate the Hub-Shipping cost, and the most economical size of ships to be used in the Hub-Shipping process can be got. Second, a mathematic programming method is developed to get the lowest Spoke-Shipping cost. Third, the range of ship size can be used in the Hub-Shipping process will be got from the results of the former two stages.Through empirical experiments and comparisons, results show that the proposed Base-Distribution Model can provide a more economical, reliable and stable solution to the program than the Direct Shipping Model. Besides, The Base-Distribution Model also can provide a more effective approach to the optimization of coastal coal shipping network structures and operations than the Direct Shipping Model does. The model proposed in this paper should be the trend of the domestic coastal coal shipment in the future. And it can also be used in other bulk cargos shipment.