Optimal Facility Location and Sizing for Waste Upcycling Systems

Abstract

For reducing the carbon footprint of products containing polymers, recycling and upcycling of waste can make important contributions. While for certain polymers, especially for thermoplastics, melting and re-forming is attractive, although it leads to a degradation of the material properties, for others, and also after a certain degree of degradation in general, chemical processing is the most attractive option for recycling (also called upcycling). This means that from the end-of-life or production waste, valuable molecules are produced that can be fed again into the production of high-value polymers, leading to circular value chains. Such value chains can replace or reduce the use of fossil-based raw materials in polymer production, but actually realizing such value chains is a complex task. It requires setting up systemic solutions, from the collection of end-of-life or production waste over dismantling, sorting, pre-conditioning to chemical processing and downstream separation. The resulting systemic solution must be viable from an economic and from an ecologic point of view. Therefore, such systems must be analyzed and optimized from a system-wide perspective. In this work, we present a framework to model, simulate, analyze and optimize circular supply chains, and we demonstrate the potential of our framework with a case study of a value chain for the upcycling of rigid polyurethane foam waste in Germany.