Removal of tar from waste textiles by molten carbonates pyrolysis in bubbling reactor

Abstract

Nowadays, the amount of waste textiles (WT) was increasing due to the increase in population, thermochemical processes owe the potential to process WT on large-scale. However, tar removal is the key to industrial thermochemical treatment. Molten carbonates pyrolysis technology is proposed to remove WT tar in this study. The result showed that molten carbonates favor catalytic reaction medium for turning tar into char and small molecular pyrolysis gases (including H2, CO, and CO2), meanwhile, excellent heat and mass transfer performance of molten carbonates can also reinforce the reaction. 94.95 wt% of tar was removed at 550 °C with flow rate of 0.15 L/min. Molten carbonates not only promoted decarboxylation of acid in tar, but also enhanced the reaction between coke and carbon dioxide, which in return benefits lifetime of molten carbonates, so after recycling eight times, tar removal rate was still above 90 %. The kinetic study suggested that lower flow rate laid positive influence on tar elimination by contributing to mass and heat transfer inside the bubbles.