Fuelling the future: Unleashing energy and exergy efficiency from municipal green waste pyrolysis

Abstract

This study aims to determine how different operating conditions for a fast pyrolysis process employing municipal green waste (MGW) in an auger reactor affect product yields, overall energy efficiency, and total exergy efficiency. In this study, a range of pyrolysis conditions, including temperatures from 400 to 600 °C (in 50 °C increments), holding times from 1 to 5 min (in 1-minute increments), and feedstock particle sizes from 2 to 10 mm (in 2-mm increments) were used. MGW and pyrolysis products were characterised using separate pieces of equipment and in accordance with applicable ASTM standards. The results demonstrate that a yield of 52.8% for bio-oil and a yield of 23.7% for syngas can be achieved at temperatures of 500 and 600 °C, respectively. At 400 °C, the biochar production was highest as 21.5%. Bio-oil and syngas yields improved with holding times, whereas biochar yields declined. At a feedstock particle size of 2 mm, the overall energy efficiency was at its maximum (72.9%), while the total exergy efficiency was also at its highest (68.4%). As feedstock particle size increased, overall energy efficiency and total exergy efficiency dropped. In conclusion, this study provides valuable insights into the effects of different operating parameters on the pyrolysis process using MGW, which can be used to optimize the process and increase its efficiency.