原油远洋拼船运输方案优化研究

Optimization of ocean shipping schemes of LCL crude oil

分析当前运作模式下中国原油远洋运输优化的目标函数,总结供需平衡约束等7类运输优化限制条件,建立原油远洋拼船运输方案的优化模型,并应用改进差分进化算法求解。在模型求解过程中,对多种维度变量与约束因素数据进行有效整合,利用双染色体配对编码的方法实现供需平衡限制,通过配对染色体间的小概率交叉降低算法的早熟收敛概率,利用整体进化与个别进化相结合的方法回收潜在的优秀个体,最终加速算法的寻优速率。通过算法搜索方案与人工方案的比对结果发现,应用提出的改进差分进化算法能够降低原油远洋拼船运输方案费用,并有效提高优化方案的制定时效。

As an extension and development of oil and gas storage and transportation, the optimization of crude carrier co-loading scheme plays an important role in improving the profit and reducing loss in terms of crude oil logistics, which is of great importance in upgrading the overall competitive strength for the oil and petrochemical companies in China. The objec-tion function on the optimization of long-distance crude oil transportation was analyzed, and seven constraints, such as the balance of supply and demand were concluded, which set limits on the extent to which the system will work. An optimization model of crude carrier co-loading scheme was established by using an improved differential evolution algorithm. The equation constrained was satisfied by the method of paired chromosomes. Some constraints were simplified by the form of additional distance. The crossover of small probability between paired chromosomes was used to prevent premature convergence. Final-ly, to recycle some potential excellent genes and to speed up the algorithm optimization, some chromosomes of high 'semi-fitness' were selected for individual evolutions during the execution of differential evolution algorithm. Compared with manual searching plans, this improved differential evolution algorithm can not only significantly reduce the cost in long-distance crude oil co-loading and transportation, but also save the time in optimizing the crude carrier co-loading schemes.