摘要
针对生物油组分复杂,难以直接应用的问题,该研究开展了不同生物油的分子蒸馏馏分分布规律的研究,并考察了不同原料和温度对生物油分子蒸馏分离特性的影响。热解液化试验结果表明,生物油组分以酸、醛、酮、酚、糖为主。随着热解温度的升高,松木生物油中轻质组分产率由21%不断降低至11%,而秸秆生物油中轻质组分产率稳定在20%左右。高温生物油各组分的平均分子自由程两极化程度加强,600℃制备轻质油蒸出比例最高,可以达到92%(松木)和86%(秸秆)。酚类化合物中酚羟基的数量可以影响其分离特性,较高的热解温度促进了酚羟基的产生,从而使酚类物质从蒸出部分(distillation fraction,DF)向残留部分(residual fraction,RF)中转移。分子蒸馏技术能够实现对不同生物油的有效分离,得到的DF中主要包含酸、酮和小分子酚类,RF则以糖和大分子酚为主,除了羟乙醛和苯并呋喃等化合物外,生物油中的大部分化合物的富集程度都可以达到90%以上。该研究可为快速热解生物油的分离及其后续提质研究提供一定的参考。
Bio-oil is one type of liquid product from the pyrolysis liquefaction of biomass.The heat-sensitive liquid with high water content and complex components can be further processed and then refined for the subsequent application.Moreover,the more large molecules of phenolics and sugars in the bio-oil are prone to serious coking on the catalyst during refinement.In this study,a systematic investigation was carried out on the distribution pattern of molecular distillation fractions in the different bio-oils.Two feedstocks(pine and maize stover)and temperatures(500,550,and 600℃)were selected to evaluate the separation of bio-oils using molecular distillation.The pyrolysis liquefaction test was carried out by a bubbling fluidized bed reactor.The experiment showed that the bio-oil components were dominated by acids,aldehydes,ketones,phenols,and sugars.Both feedstock and pyrolysis temperature dominated the yield of bio-oil.Specifically,the yield of light components in pine biooil decreased continuously from 21%to 11%with the increase in pyrolysis temperature.While the yield of light components in maize stover bio-oil was stabilized at about 20%.There was a strong polarization in the mean free path of each component in the bio-oil at high temperatures.Once the pyrolysis temperature increased from 500 to 600℃,the evaporation percentage of pine light oil increased to 92%,while that of maize stover light oil increased to 86%.The molecular distillation was realized to separate more than 90%of water,acids,ketones and small molecules in the bio-oils.But it was difficult to separate the larger molecules of sugars.The separation of phenolics differed greatly from the number of phenolic hydroxyl groups;Monophenolics were easily vaporized,and thus more enriched in the distillation fraction(DF);While diphenolics were more difficult to be vaporized and thus more enriched in the residual fraction(RF).Higher pyrolysis temperatures promoted the conversion of methoxy into the phenolic hydroxyl groups in the bio-oil phenolics.The incr
作者
孙志景
易维明
张德俐
林鹏
张奇
马瑞
朱玲君
SUN Zhijing;YI Weiming;ZHANG Deli;LIN Peng;ZHANG Qi;MA Rui;ZHU Lingjun(College of Agricultural Engineering and Food Science,Shandong University of Technology,Zibo 255000,China;Shandong Research Center of Engineering&Technology for Clean Energy,Zibo 255000,China;State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2024年第7期260-268,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金重点项目(52130610)。
关键词
生物油
热解
分子蒸馏
分离特性
生物质
bio-oil
pyrolysis
molecular distillation
separation characteristics
biomass
