System Analyses of High-Value Chemicals and Fuels from a Waste High-Density Polyethylene Refinery. Part 1: Conceptual Design and Techno-Economic Assessment

The increasing amount of plastic waste generation has become an important concern for the chemical industry and government agencies due to high disposal and environmental leakage rates. Chemical recycling is a promising technology due to the potential reduction of pollutant emissions and the establishment of a circular economy through the production of monomers and fuels. However, there is scarce information on industrial scale processes of this technology and their energetic, economic, and environmental performance. Therefore, the present process modeling study presents a novel multiproduct pyrolysis-based refinery for the conversion of 500 tonnes/day of waste high-density polyethylene (HDPE). The products obtained from the modeled refinery were chemical grade ethylene and propylene, an aromatics mixture, and low- and high-molecular weight hydrocarbon mixtures (MWHCs). Part 1 of this study focuses on the energetic and economic evaluation of the refinery and the potential effects of heat integration. The energy efficiency was 68% and 73% for the base case and the heat integrated refinery, respectively. The net present values (NPVs) were 367 and 383 million U.S. dollars (MM USD), for the base case and the heat integrated process, respectively. These results suggest energetic and economic sustainability of the design and its promising application on an industrial scale.