Improved Catalytic Technology for Waste Plastic Processing: Toward Novel Remediation and Emission Control Measures

Abstract

A mesoporous zeolite USY to process waste plastic, illustrated on low-density polyethylene, is presented. The technology is mobile and can be used as a remediation and control measure to the emissions in the open environment. The core of this approach lays on the catalytic material employed. It is a zeolite USY that possesses both micropores (up to 2 nm) and mesopores (between 2 and 50 nm) that was prepared by desilication using a mixture of mesopore inducing agents, tetra-butyl ammonium hydroxide and sodium hydroxide. This gives rise to a well-defined zeolite USY with double intracrystalline mesoporosity and higher intrinsic acidity. Those improvements had a positive impact on the cracking of low-density polyethylene, with a lowering of the cracking temperature, ascribed to the enhanced mass transfer of the reactant into the acid sites. The lowering of the reaction temperature reduces the energy requirements with operational savings of 0.50 MW with respect to the thermal process and 80 kW with respect to the untreated zeolite for a plant of 50 kt per year, though the scale of operation can be adjusted to the local requirements. The lower operation temperature triggered by the catalyst has also benefits in terms of lower capital investment since low-cost construction materials would be required. The zeolite preparation is industrially scalable. All these features make the deployment of this technology a realistic option.