This research investigated the oxidative torrefaction behavior of Leucaena over a temperature range of 220 to 260 °C and varying O₂ concentrations from 0 to 22 vol%. Mass yield decreased with increased temperatures and O₂ concentration, and H₂O was the main gaseous product during oxidative torrefaction. The yields of H₂O, CO₂, and CO increased continuously with the increase in O₂ concentration. The carbon content in Leucaena increased with the increase in temperatures. At 220 °C and 240 °C, the carbon content increased with O₂ concentration and had a peak at O₂ concentration of 10%. On the other hand, the carbon content at 260 °C had a peak at an O₂ concentration of 5%. At 240 °C, the HHV of torrefied biomass increased to 20.5 MJ/kg at an O₂ concentration of 10%, while at 260 °C, the HHV of torrefied biomass increased to 21.4 MJ/kg at an O₂ concentration of 5%. The combustion characteristics of oxidative torrefied Leucaena clearly demonstrated a decrease in the combustion rate of the volatile components and an increase in the combustion rate of the char as the concentration of oxygen increased. From the analysis of gas formation rates and chemical properties of the torrefied Leucaena, it was suggested that O₂ played an important role in two ways: At low temperatures, the O₂ accelerated the dehydration and decarboxylation reactions resulted in low O/C ratios, while at high temperature, the O₂ participated in partial combustion of biomass and resulted in higher O/C ratios.

Graphical abstract

中文翻译：

---

氧气浓度对银合欢烘焙的影响：气体形成速率和化学性质分析

本研究调查了银合欢在 220 至 260 °C 温度范围内以及 O ₂浓度从 0 至 22 vol% 变化的氧化烘焙行为。质量收率随着温度和O ₂浓度的增加而降低，并且H ₂ O是氧化烘焙过程中的主要气态产物。随着O ₂浓度的增加， H ₂ O、CO ₂和CO的产率不断增加。银合欢中的碳含量随着温度的升高而增加。在220℃和240℃时，碳含量随着O _{2浓度的增加而增加，并在O 2}浓度为10%时出现峰值。另一方面，260℃下的碳含量在O ₂浓度为5％时具有峰值。在240℃时，O ₂浓度为10%时，烘焙生物质的HHV增加至20.5MJ/kg；而在260℃时，O ₂浓度为5%时，烘焙生物质的HHV增加至21.4MJ/kg。 。氧化烘焙银合欢的燃烧特性清楚地表明，随着氧浓度的增加，挥发性成分的燃烧速率降低，而木炭的燃烧速率增加。通过对烘焙银合欢的气体形成速率和化学性质的分析，表明O ₂在两个方面发挥了重要作用：在低温下，O ₂加速脱水和脱羧反应，导致O/C比低，而在高温下，O ₂参与生物质的部分燃烧，导致较高的O/C比。

图形概要