Synergistic effects of biomass building blocks on pyrolysis gas and bio-oil formation
Synergistic effects of biomass building blocks on pyrolysis gas and bio-oil formation
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DOI：
10.1016/j.jaap.2021.105100
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发表时间：
2021-03
影响因子：
6
通讯作者：
Andrew H. Hubble;Jillian L. Goldfarb
中科院分区：
文献类型：
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作者：
Andrew H. Hubble;Jillian L. Goldfarb
在生物基燃料取代化石燃料之前，必须解决几个关键问题。通过热解木质纤维素材料得到的生物油具有高酸度和粘度，以及差的能量密度和稳定性。为了解决这些问题，本文研究了木质纤维原料组分的单独和组合行为，以揭示通过生物质混合产生优先生物燃料特性的潜力。干木质纤维素生物质主要由细胞壁多糖（纤维素、半纤维素、木质素）组成，其在生物质中的类型和浓度变化很大。这种异质性导致热解期间生物基燃料形成的不可预测性增加。利用微分热重（DTG）分析，气相色谱-质谱，和残余气体分析，这项工作探讨了协同作用的木质纤维素生物质组分在热解过程中操纵生物油和气体产品组合物的基础上所需的化合物类。将纤维素、木糖、木聚糖和木质素以不同比例混合以确定热解过程中协同效应的程度。对于每种混合物，通过将各个行为（例如，质量损失速率、H2气体释放等）相加来开发"预期"结果。基于存在的质量分数的单个组分的含量。含有木质素和/或木聚糖的混合物在比预测的更低的温度下产生DTG质量损失率峰值，生物炭产率相应降低，这表明促进脱挥发分的协同相互作用。木质素本身产生大量氢气，当与其他生物质混合时，促进脱氢。木质素增加CO2的形成，导致生物油和生物炭中的氧浓度较低。在抑制生物油生成的同时，木质素的存在（即使在低浓度下）增加了所产生的酚化合物的数量，同时降低了呋喃的产率。不同多糖之间的协同相互作用可以根据所需的生物炼制产品来利用-允许有针对性地选择木质纤维素生物质混合物以微调所得燃料。
Before biobased fuels can replace fossil fuels, several key issues must be addressed. Bio-oils derived through pyrolysis of lignocellulosic material have high acidity and viscosity, and poor energy density and stability. To address these issues, this paper examines the individual and combined behavior of lignocellulosic feedstock components to shed light on the potential to generate preferential biofuel properties through biomass mixing. Dry lignocellulosic biomass is mostly composed of cell wall polysaccharides (cellulose, hemicellulose, lignin), which vary widely in type and concentration across biomasses. This heterogeneity leads to increased unpredictability in biobased fuel formation during pyrolysis. Using derivative thermogravimetric (DTG) analysis, gas chromatography-mass spectroscopy, and residual gas analysis, this work explores the synergistic interactions of lignocellulosic biomass components during pyrolysis to manipulate bio-oil and gas product composition based on desired compound classes. Cellulose, xylose, xylan, and lignin were blended at different ratios to determine the extent of synergistic effects during pyrolysis. For each mixture, an ‘expected’ outcome was developed by summing the individual behavior (e.g. mass loss rate, H2gas evolution, etc.) of the individual components based on mass fraction present. Mixtures containing lignin and/or xylan yield peak DTG mass loss rates at lower temperatures than predicted with corresponding reductions in biochar yield suggesting synergistic interactions that promote devolatilization. By itself, lignin produces large amounts of hydrogen gas, and when mixed with other biomasses promotes dehydrogenation. Lignin increases CO2formation, resulting in lower oxygen concentrations in the bio-oil and biochar. While suppressing bio-oil generation, the presence of lignin – even at low concentrations – increases the number of phenol compounds produced, while decreasing the yield of furans. The synergistic interactions between different polysaccharides could be exploited depending on the desired biorefinery products – allowing for targeted selection of lignocellulosic biomass mixes to fine-tune resulting fuels.