Wang Anni, Hu Jianhang, Zhang Long, Wang Hua
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, China.
Engineering Research Center of Metallurgical Energy Conservation and Emission Reduction, Ministry of Education, Kunming University of Science and Technology, Kunming, China.
Front Chem. 2025 Jun 11;13:1603584. doi: 10.3389/fchem.2025.1603584. eCollection 2025.
Aiming at the issues of low yield and poor quality of bio-oil obtained from direct pyrolysis of biomass, in this study, waste tobacco stems (TS) were used as raw materials, and the pretreatment methods of torrefaction and acid washing were adopted to study the effects of different torrefaction temperatures and pretreatment sequences on the quality of TS biomass and bio-oil. Results showed that combined pretreatment synergistically integrated deoxygenation from torrefaction and deashing from acid washing. High-temperature torrefaction-based combined pretreatment reduced TS oxygen content from 54.83% to 20.14%. Acid washing pretreatment achieved more than 90% removal of inorganic elements (K, Cl and Mg). The order of combined pretreatment also had an important influence on biomass pyrolysis. Torrefaction-acid washing pretreatment decreased ash content of TS, increased the relative content of sugars and aromatic compounds in bio-oil, reduced alcohols and ketones relative contents, and improved bio-oil higher heating value (HHV) and pH. Acid washing-torrefaction pretreatment enhanced bio-oil productivity, increased nitrogen-containing compounds and phenols relative content, reduced acids and aldehydes contents, and lowered bio-oil water and ash contents. Additionally, with the increase in torrefaction temperature, the O/C molar ratio of TS decreased, the HHV of TS increased, and the thermal cracking of nicotine in bio-oil to generate pyridine compounds was promoted. This study demonstrates a viable pathway to convert TS into high-quality fuels and bio-oil via combined pretreatment, offering new insights for optimizing biomass pyrolysis technology and enhancing resource utilization efficiency.
针对生物质直接热解生物油产率低、品质差的问题，本研究以废弃烟梗（TS）为原料，采用烘焙和酸洗预处理方法，研究不同烘焙温度和预处理顺序对TS生物质及生物油品质的影响。结果表明，联合预处理协同整合了烘焙脱氧和酸洗脱灰的效果。基于高温烘焙的联合预处理使TS的氧含量从54.83%降至20.14%。酸洗预处理实现了无机元素（钾、氯和镁）90%以上的去除。联合预处理的顺序对生物质热解也有重要影响。烘焙-酸洗预处理降低了TS的灰分含量，提高了生物油中糖类和芳香族化合物的相对含量，降低了醇类和酮类的相对含量，并提高了生物油的高位发热量（HHV）和pH值。酸洗-烘焙预处理提高了生物油产率，增加了含氮化合物和酚类的相对含量，降低了酸类和醛类含量，并降低了生物油水含量和灰分含量。此外，随着烘焙温度的升高，TS的O/C摩尔比降低，TS的HHV增加，生物油中尼古丁热裂解生成吡啶类化合物的反应得到促进。本研究证明了通过联合预处理将TS转化为优质燃料和生物油的可行途径，为优化生物质热解技术和提高资源利用效率提供了新的见解。
