Catalytic co-pyrolysis of coffee grounds and polyethylene: A comparison of HZSM-5 and HY

Abstract

The effects of the HZSM-5 and HY catalysts on the co-pyrolysis performance and product distribution of coffee grounds and polyethylene (CP73) were characterized via thermogravimetric analyzer with Fourier transform infrared spectroscopy and pyrolysis–gas chromatography-mass spectrometry. The addition of HZSM-5 and HY facilitated the decomposition of CP73 and reduced its residual content. HY-catalyzed CP73 (CP73/HY) exhibited the lower residual content, with a 9.09 % decrease, than did CP73 (eliminating the influence of the mixing ratio). The addition of the catalysts did not enhance the pyrolysis performance of CP73; however, an increase in the mean decomposition rate promoted its decomposition. The addition of the catalysts significantly reduced the activation energy of CP73 to varying degrees. The maximum reduction in the activation energy occurred with CP73/HY, from 218.58 kJ/mol for CP73 to 191.86 kJ/mol. The addition of HY and HZSM-5 produced up to 35.94 % and 46.43 % aromatics, respectively, relative to that of CP73. In particular, CP73/HZSM-5 generated a higher quantity of monocyclic aromatics, whereas CP73/HY produced a greater amount of alkylbenzenes than did CP73. This study provides actionable insights into the practical implementation of the catalytic co-pyrolysis of biomass and plastics.