Upgrade of bio-oil produced from the sisal residue composting

The present work studies the composting effects on the chemical characteristics of bio-oil produced by pyrolysis of sisal residue. Three systems were composted with sisal residue proportions to sisal fiber powder of 100:0, 90:10, and 75:25, respectively. The systems showed reductions of 33–48% (extractive), 70–80% (hemicellulose), and 80–90% (cellulose) after composting. An increase in lignin content was observed in all systems. The pyrolysis of the composted systems was performed at 450 and 550 °C. At both temperatures, this process was selective in producing a large concentration of hydrocarbons (>160% increase), mainly alkanes and alkenes, reducing the concentrations of ketones, aldehydes, and phenolics (>50%) and eliminating esters, furans, and acetic acid to composted biomasses. The higher temperature favored aromatics and cyclic hydrocarbon production from the pyrolysis of composted samples. In addition to these results, composting helped reduce the oxygenated bio-oil species by approximately 44 - 75% at the lowest and ~ 69% at the highest temperatures. These results indicate that composted sisal residue can produce bio-oils that are more suitable for biorefineries since they are rich in aliphatic hydrocarbons and non-oxygenated species.本研究探讨了堆肥处理对剑麻残渣热解制备生物油化学特性的影响。实验设置了三个堆肥体系，其剑麻残渣与剑麻纤维粉的质量比分别为100:0、90:10和75:25。堆肥完成后，各体系的萃取物、半纤维素与纤维素分别降低了33%~48%、70%~80%及80%~90%，而所有体系的木质素含量均出现上升。随后对堆肥后的样品分别在450℃与550℃下开展热解实验：在两个温度下，该热解过程均表现出优异的产物选择性，可高浓度生成烃类物质（增幅超160%），主要成分为烷烃与烯烃；同时大幅降低酮类、醛类及酚类物质的浓度（降幅超50%），并可完全去除堆肥生物质中的酯类、呋喃类物质与乙酸。较高的热解温度更有利于促进堆肥样品热解生成芳烃与环烃类产物。此外，堆肥处理还可使含氧生物油组分在最低热解温度下减少约44%~75%，在最高热解温度下减少约69%。上述结果表明，经堆肥改性的剑麻残渣可用于制备更适配生物炼制厂的生物油，这类生物油富含脂肪烃与非含氧组分。