Pyrolysis Gas Analysis of Ethylene-vinyl Acetate (EVA) and Poly-vinylidene Fluoride (PVDF) Polymers Encapsulated in c-Si Photovoltaic Solar Module to Facilitate Recycling

A detailed analysis of the gases evolved during pyrolysis of the End-of-Life (EOL) crystalline silicon photovoltaic (c-Si PV) solar module, focusing on recycling strategies has been reported herein. PV modules encapsulated with Ethylene-vinyl acetate (EVA) – with and without Poly-vinylidene fluoride (PVDF) polymer backsheet were pyrolyzed at 500 °C and evolve gases was collected in the gas cell. Further another sets; pyrolysis gases at 500 °C passes through a water bubbler, and 700 °C pre-heated burner and end gases were collected in gas cell. This study utilizes Fourier Transform Infrared (FTIR) spectroscopy to analyse the collected gases. This would help determine the appropriate processing conditions to minimize the environmental impact of EOL recycling of PV modules by pyrolysis. Surface morphology, glass transmittance, and peel adhesion of PV module glass and EVA were characterized to facilitate re-lamination of new modules using recycled glass. Experimental findings include specific toxic gas emission observed with PVDF pyrolysis, the impact of burner and water bubbler treatments on gas emissions, minimal reduction in glass transmittance, and peel adhesion retention in recycled glass. This suggesting a potential recycling approach involving pyrolysis at 500 °C, followed by gas passes through water bubbler, to minimize environmental impact, while reusing recycled glass for new module fabrication. The best recycling steps also proposed for future research work on complete recycling of c-Si PV modules.