Catalytic pyrolysis of wind turbine blades waste for plasticizers recovery and its life cycle assessment

Abstract

This research aims to recover the plasticizers compounds and glass fibers (GFs) from wind turbine blade waste (WTB: GFs reinforced unsaturated polyester resin) breakdown its styrene toxic compound into light hydrocarbons using catalytic pyrolysis. The catalytic conversion process was conducted on WTB using a single small fixed-bed pyrolysis reactor over Y-type zeolite catalyst and different pyrolysis temperatures. The solid residue was subjected to sieving, washing, and oxidation as post-treatments to liberate GFs. The catalytic pyrolysis products were examined using GC/MS, GC/TCD, SEM-EDX, and FTIR. The life cycle assessment (LCA) of this approach was also studied based on ISO 14040/44 standards and compared with the typical pyrolysis of WTB. The results showed the success of the catalytic pyrolysis in converting WTB into oil (13–14.2 wt%), gaseous (10.4–12.8 wt%), and solid residue (74.2–75.4 wt%). The GC/MS results showed the absence of styrene in the oily product and terephthalic acid, di(2- ethylhexyl) ester (up to 93.35 %) and benzene, 1,1'-(1,3-,propanediyl)bis-compounds, which represent the main components associated with plasticizer production, were strongly present up to 93.35 % (650 °C). While hydrogen was the predominant flammable gas in the gaseous product, especially at 650 °C. The LCA results showed that catalytic pyrolysis may add additional environmental burdens to WTB management due to the inclusion of spent catalyst regeneration in the modelling process, as well as the implementation of conversion and upgrading operations in a single stage using a single reactor. Accordingly, it is highly recommended to implement the WTB conversion and upgrading process using two-stage reactors in future works to avoid the use of too much catalyst and its pollution, thus reducing the environmental burden of this approach.