Decentralized pyrolysis of hospital plastic waste for diesel-range fuel recovery: a technological and economic feasibility study

The escalating accumulation of hospital plastic waste, primarily composed of polypropylene and polyethylene, poses a pressing environmental challenge due to the widespread use of disposable medical items and inadequate waste management practices. This study explores the thermochemical valorization of selectively decontaminated hospital plastic waste via batch pyrolysis conducted at 400°C–500°C under an inert nitrogen atmosphere. Optimal pyrolysis conditions 475°C, 20°C/min heating rate, and 45-minute retention time yielded a maximum of 62 wt% pyrolytic oil. Gas chromatography–mass spectrometry revealed that the oil’s composition predominantly comprises C₁₂-C₂₂ linear aliphatic hydrocarbons, indicating its suitability as a diesel-range blendstock. The oil had a calorific value of 41.2 MJ/kg, a viscosity of 3.6 cSt, and a density of 845 kg/m³. By-products included syngas (18 wt%) with a lower heating value of 16 MJ/m³ and char (20 wt%) with 52% fixed carbon, ensuring comprehensive energy recovery. Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy detected no chlorine-containing compounds above ~0.1 wt%, suggesting effective exclusion of polyvinyl chloride. A techno-economic analysis of a 10 kg/h modular pyrolysis unit indicated an energy offset of ~50 kWh/day and a payback period of 1.5–2 years. These findings highlight the technical, economic, and environmental feasibility of deploying decentralized pyrolysis units within hospital infrastructure, thereby advancing circular-economy principles and sustainable plastic-waste management, aligned with global sustainability goals.