(704e) A Greener Future for PPE Waste: Sustainable Upcycling in the Petrochemical Industry By Catalytic Pyrolysis

The disposal of used Personal Protective Equipment (PPE), particularly disposable surgical masks (FM) and nitrile gloves (NG), contributes significantly to global waste, often ending up in oceans, landfills, or through incineration. Recycling of PPE waste remains economically unfeasible and lacks tailored strategies, particularly for these materials [1]. Pyrolysis, a thermal process that converts solid wastes into energy and value-added products, offers a promising solution for PPE recycling. This study investigates the impact of various catalysts on the pyrolysis of a 50:50 mass mixture of FMs and NGs, focusing on product yield, composition, kinetics, and economic feasibility. The pyrolysis was conducted in a fixed-bed reactor, and the effects of temperature (500-800°C) and catalyst type, including natural olivine and metal oxide (Gd/CeO₂), were analyzed. The non-catalytic pyrolysis was then validated at 0.3 kg/h scale using an auger reactor. Thermal pyrolysis yielded a high proportion of condensable products, with oil and wax peaking at 77 wt.% at 600°C, producing aliphatic compounds such as alcohols, cycloalkanes, and alkenes. Catalytic pyrolysis using olivine improved product quality by homogenizing the carbon distribution, increasing the heating value, and reducing contaminants such as metals and halogens, making the condensable product more suitable for refinery entry. Aspen Plus simulations predicted the economic viability of the pyrolysis process, with olivine catalysis demonstrating a shorter payback time and higher net present value (NPV) after 20 years, provided the plant processes over 50,000 tonnes per year. The addition of Gd-CeO₂ increased gas yield and enhanced cracking, producing a gas composition rich in hydrocarbons and CO. Overall, catalytic pyrolysis of mixed PPE waste presents a sustainable and economically promising recycling method, with further refining options, such as hydrotreatment, offering potential for improved product quality and market integration.

References:

[1] OECD, Global Plastics Outlook: Policy Scenarios to 2060, OECD Publishing, Paris, 2022.