The inventory-routing problem of returnable transport items with time windows and simultaneous pickup and delivery in closed-loop supply chains

摘要

Reducing environmental impact, related regulations and potential for operational benefits arethe main reasons why companies share their returnable transport items (RTIs) among thedifferent partners of a closed-loop supply chain. In this paper, we consider a producer, locatedat a depot, who has to distribute his products packed in RTIs to a set of customers. Customersdefine a time window wherein the service can begin. The producer is also in charge of thecollection of empty RTIs for reuse in the next production cycle. Each partner has a storage areacomposed of both empty and loaded RTI stock, as characterized by initial levels and maximumstorage capacity. As deliveries and returns are performed by a homogeneous fleet of vehiclesthat can carry simultaneously empty and loaded RTIs, this research addresses a pickup anddelivery inventory-routing problem within time windows (PDIRPTW) over a planning horizon.A mixed-integer linear program is developed and tested on small-scale instances. To handlemore realistic large-scale problems, a cluster first-route second matheuristic is proposed.