在大规模海铁联运网络背景下,考虑铁路年运输能力和煤炭港口年吞吐量限制的基础上,引入阶梯式碳税量化碳排放成本,建立考虑碳排放的煤炭海铁联运网络调运方案非线性优化模型.模型以大规模海铁联运网络每条可行路径的年煤炭运输量为决策变量,根据模型特性设计了一种组合式求解算法(Combinatorial Algorithm,CA),外层迭代算法采用增广拉格朗日乘子法,内层迭代算法采用可行方向法,将非线性规划模型转化为标准Hitchcock模型.采用国家能源集团煤炭海铁联运业务相关数据进行实例分析,并运用CA进行求解.在实例分析的基础上进一步对固定碳税和阶梯式碳税进行了敏感性分析,结果表明,阶梯式碳税上下限在合理度范围内时,采用其得到的最优调运方案在企业总效益和减排效果2个方面优于固定碳税,但当其上下限超出合理范围后,会对企业效益及企业减排积极性产生打击.
In the context of a large-scale sea-rail intermodal transportation network,considering the annual transport capacity of railways and the annual throughput of coal ports,this paper introduced a tiered carbon tax to quantify carbon emission costs.A non-linear optimization model for the coal sea-rail intermodal transportation network was built.The model took the annual coal transportation volume along each feasible path in the large-scale sea-rail intermodal transportation network as decision variables.A combinatorial algorithm(CA)was designed based on the characteristics of the model,where the outer iteration algorithm employed the augmented LaGrange multiplier method,and the inner iteration algorithm employed the feasible direction method,transforming the non-linear programming model into a standard Hitchcock model.The instance analysis was conducted by relevant data from the coal sea-rail intermodal transportation business of the China Energy Investment Group Co.,Ltd,and the CA was applied for the solution.Based on the instance analysis,sensitivity analyses were further performed on fixed carbon taxes and tiered carbon taxes.The results indicate that within a reasonable range of upper and lower limits for tiered carbon taxes,the optimal transportation scheme derived from it outperforms fixed carbon taxes in terms of overall enterprise benefits and emission reduction effects.However,when the upper and lower limits exceed a reasonable range,it adversely affects enterprise benefits and the motivation for emission reduction.