The retrofit of a closed-loop distribution network: the case of lead batteries

摘要

Recent advances in global competition with the exhaustion of natural resources, and thernincreased society awareness towards environment created a new way of thinking whenrnmanaging supply chains. Companies are now facing the need of seriously consideringrnwithin their supply chain the presence of their end-of-life products. The concept ofrnclosed-loop supply chains has emerged where optimized structures are required. In thisrnpaper the design and planning of a real closed-loop supply chain is studied consideringrnthe production of lead batteries its distribution to the final clients and its collection atrnthe end-of-life period. The company with a wide distribution network, at Portugal level,rnand a fleet of owned vehicles reached effectiveness in the delivery service to the finalrncostumer. It is now vital to reach efficiency at costs level. To help reaching this goal thernpresent work looks into the retrofit of the existing structure so as to achieve thernoptimized design of the closed-loop supply chain. A Mixed Integer LinearrnProgramming (MILP) model is developed which simultaneously designs the forwardrnand reverse chains. Various scenarios are built from which decisions regarding thernretrofit of the existing network (namely, elimination, addition and replacement ofrnwarehouses) are obtained with a significant reduction of costs. The contemplated costsrnare: the cost of opening warehouses, the cost of the raw materials acquire to suppliersrnand of used products acquire to customers, as well as the cost of the differentrntransportation resources. Besides strategic design, plans of supply, production, storagernand transportation are also given by the model. The results obtained are compared withrnthe existing network and important conclusions are drawn.