TG-FTIR-MS and Py-GC/MS study on the pyrolysis characteristics and gas evolution behavior of forest duff

Abstract

Temperate and boreal duff layers are well-distributed in forests and swamps across North America, Europe, and Asia. Despite its abundance, forest duff remains predominantly a fire load or forest redundancy rather than being developed as a biofuel. This study analyzed the pyrolysis characteristics and gas evolution behavior of forest duff at different heating rates and pyrolysis temperatures by coupling technique TG-FTIR-MS and Py-GC/MS. The pyrolysis behavior of forest duff was modeled by a parallel reaction scheme encompassing water evaporation and hemicellulose, cellulose, and lignin degradation. The calculated decomposition temperature ranges of hemicellulose, cellulose, and lignin were 180–400 °C, 220–540 °C, and 200–800 °C, respectively. The temperature zones for the primary mass conversion were 200–500 °C, from which the main functional groups and volatile products were C-O-C, CO, -CnH2n+1, -OH, and non-condensable gases (CO2, CO, and CH4). The carbohydrate and ketone yields peaked at 288 °C, whereas the maximum acid and ester yields were at 320 °C. The yields of furans, phenols, and aromatics increased with pyrolysis temperature, peaking at 622 °C. This study elucidates the influence of the heating rate and pyrolysis temperature on the selectivity of bioenergy and value-added chemicals from forest duff pyrolysis.