生物油及其重质组分的热解实验研究

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	生物油及其重质组分的热解实验研究
其他题名	The Study on Pyrolysis Characteristics of Bio-oil and its Heavy Fractions
	武景丽
导师	吴创之
	2008-06-03
学位授予单位	中国科学院广州能源研究所
学位授予地点	广州能源研究所
学位名称	硕士
关键词	生物油重质组模型化合物热重红外联用热解
摘要	生物质热解制油技术作为生物质热化学转化领域中的前沿技术受到了较多关注。生物油作为初级的液体燃料，既可以将其改质提升成高品位液体燃料，也可以将其气化制备合成气，再合成新的液体燃料。生物油改质主要集中在催化加氢和催化裂解两个方面，其中，生物油重质组分不易在加氢、裂解与重整过程中直接分解，通过研究发现生物油重质组分中多酚的慢速聚合和缩合反应是导致生物油“老化”的重要原因；醛类和糖类等大分子物质在一定条件下聚合反应生成的低聚物导致生物油裂解不完全，因此，对生物油改质的研究尚处在初级阶段。为了提高生物油的利用效率，特别是提高生物油中的不易分解的重质组分的利用效率，更好地处理生物油热解与气化过程中出现的问题，寻找生物油新的利用方法备受关注，而生物油气化制备合成气的技术路线引起了国内外学者的广泛兴趣。本文首先对由木屑热解得到的生物油进行了各种理化特性的分析，之后利用热重、热重-红外联用、管式炉等对生物油重质组分模型化合物的热解特性进行了实验研究，并与生物油热解特性作对比。生物油重质组分模型化合物在氮气气氛、不同升温速率下的热重分析实验表明：升温速率的升高使得生物油重质组分模型化合物的初始失重温度、失重峰值温度及对应的最大失重速率均有所增大，升温速率对最终失重量影响较小。采用热重-红外（TG-FTIR）联用技术，对生物油及其重质组分模型化合物热解过程中所释放的气体进行了实时监测，在线分析结果表明：生物油热解反应初始阶段主要析出物为自由水、低沸点的酸类、醇类、醛类、酮类等，随后以H2O、CO2等为主（主要来自重组分的裂解）。重质组分模型化合物中酚类物质最易热解，其次是醛类物质，糖类物质的热解分为两段。提高生物油的热解效率，关键在提高生物油中糖类等大分子的热解效率。生物油重质组分模型化合物的管式炉热解实验表明：随热解温度的升高，生物油重质组分模型化合物产气量不断提高，热解气体产物中主要包含H2、CO、CO2及烃类如CH4、C2H4、C2H6等,丁香酚的产气低位热值在22.7～24.4MJ/Nm3之间。
其他摘要	Bio-oil，the only liquid product in fast pyrolysis process of biomass has been expected to be very promising in the future, and the technique of pyrolysis of bio-oil has also been attracted considerable attention in the field of thermal chemical conversion recently. Bio-oil is the complex mixture in the process of depolymerization of lignin, cellulose and hemicellulose under non-thermodynamic equilibrium conditions, and it can only be treated as primary liquid fuel not only because of its high oxygen content, viscosity, but also the corrosivity and low calorific value. Many researches have focused on bio-oil’s applications and further treatments. Hydrogenation and catalytic cracking has been attracted much attention in upgrading bio-oil, It’s been found out that heavy component of bio-oil is difficult to crack in the above two cases and in reforming. For the purpose of improving efficiency of bio-oil exploitation and achieving better solutions to problems occurred during bio-oil pyrolysis and gasification ,as well as providing necessary data for the design of pyrolysis and gasification equipments, the physicochemical properties analysis of bio-oil produced from wood powder by self-heating biomass fast pyrolysis facility was carried out initially. Then TG, TG-FTIR and tube furnace were employed to investigate pyrolysis characteristics of bio-oil and model compounds of its heavy fractions. Finally, the design of a domestic entrained-flow reactor is introduced for improving efficiency of bio-oil utilization. The thermogravimetric analysis of bio-oil and model compounds of its heavy fractions were carried out under high purify N2 atmosphere from room temperature to a maximum temperature of 930℃ with different heating rates(10℃/min～30℃/min). The results indicated that bio-oil pyrolysis occured in 2 steps. The evaporation of low-boiling point compounds occurred in the first stage,, followed by the cracking of heavy fractions. With increasing heating rate, the starting temperature of weight loss, the maximum velocity of weight loss and its corresponding temperature increased simultaneity; but no difference among the ultimate weight losses was observed. The evolving volatile products during the pyrolysis process were analyzed by FTIR, and the results indicated that: free water, released during the primary stage of bio-oil pyrolysis, flowed by acids, alcohols, aldehydes and ketones due to their low boiling point. The final products were mainly consisted of H2O and CO2 due to cracking of bio-oil heavy fractions. For the model compounds of heavy fractions of bio-oil, the online analysis showed that hydroxybenzenes had the greatest tendency to decompose, followed by aldehydes and carbohydrate. Levoglucosan pyrolysis occurred in two steps: First, it was dehydrated into small molecules such as aldehydes; and then followed by the cracking of aldehydes. Enhancing heavy fractions cracking such as carbohydrates pyrolysis plays an important role in improving efficiency of bio-oil usage. Pyrolysis of bio-oil and its model compounds of heavy fractions in tube furnace was carried out over a temperature range of 700～1000℃ under inert atmosphere. The composition and yield of the derived gases as well as distribution of the pyrolyzed product were determined. It is found that with increasing temperature the gas yield goes up. The gaseous product mainly consists of H2, CO, CO2 and hydrocarbons such as CH4、C2H4、C2H6. The heating value of eugenol is in the range of 22.7～24.4MJ/Nm3, and that of bio-oil is in the range of 22.7～24.4MJ/Nm3.
页数	52
语种	中文
文献类型	学位论文
条目标识符	http://ir.giec.ac.cn/handle/344007/5790
专题	中国科学院广州能源研究所
推荐引用方式 GB/T 7714	武景丽. 生物油及其重质组分的热解实验研究[D]. 广州能源研究所. 中国科学院广州能源研究所,2008.

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