Investigation on biomass nitrogen-enriched pyrolysis: Influence of temperature

Biomass (bamboo waste) nitrogen-enriched pyrolysis was carried out in a fixed bed with NH₃ atmosphere at 400-800 °C, and formation mechanism of N-containing species was explored in depth. Results showed that N-enriched pyrolysis greatly increased bio-oil and gas yields. H₂ yield increased sharply to 130 mL/g (32.93 vol%) and became the main composition at higher temperature, while CH₄ and CO yields deceased, and the lower heating value of gas reached ∼14 MJ/Nm³. For bio-oil, the content of phenols (main compositions) and N-containing species increased significantly, and the maximums reached 61.33% and 11.47%, respectively. While that of acetic acid (disappeared), O-containing species (aldehydes/ketones/furans/esters) and aromatics decreased largely accordingly. For biochar, Nitrogen content increased, and it contained abundant pyridininc-N, pyrrolic-N, quaternary-N, and pyridone-N-oxide. Possible reaction pathways of biomass N-enriched pyrolysis was proposed based on products evolution. In conclusion, biomass N-enriched pyrolysis could obtain high-valued N-containing chemical species and functional biochar.