Pinch-Guided Heat Integration for Hydrogen Production from Mixed Plastic Waste

The conversion of plastic waste into hydrogen offers a promising waste-to-value pathway, but its industrial viability is constrained by high external energy demand associated with thermochemical processing. This study evaluates the energy performance of hydrogen production from mixed plastic waste via pyrolysis and in-line steam reforming, with a focus on reducing utility consumption through systematic heat integration. A steady-state process model was developed in Aspen Plus for a representative mixture of polyethylene, polypropylene, and polystyrene, followed by detailed energy analysis and pinch-based heat integration using Aspen Energy Analyser. Baseline utility requirements were quantified and compared against optimised configurations incorporating targeted heat exchanger network modifications. The base-case analysis identified significant recoverable heat, enabling a reduction in total external utilities from 7.14 to 2.88 GJ h−1, corresponding to a 59.6% decrease in utility demand. Sequential heat integration scenarios further reduced heating and cooling duties while maintaining process operability, demonstrating the effectiveness of iterative, pinch-guided design. The results show that high-temperature waste-plastic-to-hydrogen systems need not be utility-dominated when energy integration is embedded at the design stage. These findings highlight heat integration as a critical enabler for improving the energy efficiency and sustainability of pyrolysis–reforming routes and provide a robust framework for developing scalable, low-carbon hydrogen production from plastic waste.