生物油热解与燃烧特性的实验研究

GIEC OpenIR > 中国科学院广州能源研究所

	生物油热解与燃烧特性的实验研究
其他题名	The Experimental Study on Pyrolysis and Combustion Characteristics of Bio-oil
	李理
导师	吴创之
	2007-06-09
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位名称	硕士
学位专业	热能工程
关键词	生物油热重管式炉热解燃烧 Bio-oil Thermogravimeric Tube Furnace Pyrolysis Combustion
摘要	Bio-oil is the liquid product from fast pyrolysis of biomass. Compared with biomass, bio-oil has a higher energy density and is cheaper to transport and store. Many researches have been done on its applications and further treatments. Using bio-oil as fuel for boilers,furnaces,diseal engines and gas turbines has been proved feasible, gasification of bio-oil for synthesis gas has also attracted considerable attention recently. To deal with the problems occurred during the combustion and pyrolysis process of bio-oil better and supply necessary data required for designing of combustion and pyrolysis equipments, the physicochemical properties analysis of bio-oil produced from wood powder by self-heating biomass fast pyrolysis facility was carried out. Then TG, TG-FTIR and tube furnace were employed to investigate the pyrolysis and combustion characteristics of bio-oil. The thermogravimetric analysis of bio-oil was carried out in high purify O2 and N2 under different heating rates(5℃/min～20℃/min) to a maximum temperature of 1000℃. The results indicated that bio-oil pyrolysis occurs in 2 steps. The first concerns the evaporation of low-boiling point compounds, then followed by the cracking of heavy fractions. Bio-oil combustion starts with evaporation followed by cracking, at last combustion of char formed during the previous steps takes place. In N2, with increases of heating rate, the starting temperature of weight loss, the maximum velocity of weight loss and temperature corresponding to it all rise, and less residue form at high heating rate. The ignition temperature of bio-oil rise with increase of heating rate, final weight loss does not change. The evolving volatile products during the pyrolysis process were analyzed by FTIR. On the basis of TG data, the kinetic fittings of each reaction period during pyrolysis and combustion were carried out. The pyrolysis process of bio-oil can be described by two first-order reactions, the combustion process can be described by three first-order reactions. Pyrolysis of bio-oil in tube furnace was carried out over a temperature range of 700～1100℃ under inert atmosphere. The composition and yield of the derived gases and 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. Its heating value is in the range of 16.9～19.1MJ/Nm3. The product distribution ratio of gas, tar and char is about 30:6:64 at 900℃. The char yield of bio-oil pyrolysis is lower than that of wood powder under the same condition, but the tar yield is higher.
其他摘要	生物质快速热解制油技术能以连续的工艺和工厂化的生产方式将木屑等生物质转化为易储存、易运输、能量密度高的生物油，是目前受到较多关注的一种转换技术。生物油既可以在锅炉中直接燃烧使用，也可用于热解气化制备合成气，再进一步合成为高品质的液体燃料。为更好地处理生物油燃烧与热解过程中出现的问题，并为燃烧与热解反应装置的设计及优化提供必要数据，本文首先对由木屑在自热式生物质热解液化装置中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、管式炉等对生物油的热解与燃烧特性进行了实验研究。生物油在氮气与氧气气氛下、不同升温速率的热重分析试验表明：生物油的热解分为两个阶段，第一阶段为生物油中低沸点有机物的挥发以及各组分间反应生成各类产物的过程，第二阶段为各种重组分的裂解过程。而生物油的燃烧则分为三个阶段，即前期的挥发与裂解和最后焦炭的燃烧过程。升温速率的升高使得氮气气氛中生物油样品的初始失重温度、失重峰值温度及对应的最大失重速率均有所增大，且在较高升温速率(20℃/min)下，较少含炭残余物形成。随升温速率升高，生物油着火温度提高，最终失重率无显著变化。采用热重-红外联用技术，对生物油热解过程中所释放气体进行了实时监测，在线分析结果表明，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，随后主要释放物为水、CO2等，主要来自重组分的裂解。最后根据热重数据对热解与燃烧各段反应进行了动力学拟合。动力学分析结果表明：氮气气氛中生物油的热解过程可用两个一级反应来描述，对应其热解过程中的两个不同阶段，而生物油的燃烧过程可用三个一级反应来表示。生物油的管式炉热解实验表明：随热解温度的升高，生物油产气率不断提高，在1100℃时达到最大值398ml/g。生物油热解气体产物中主要包含H2、CO、CO2及烃类如CH4、C2H4、C2H6等,产气热值在16.9～19.1MJ/Nm3间。在900℃下，生物油各种产物气体、残炭、焦油的比例约为30:6:64,残炭含量低于同温度下木粉热解结果，而焦油含量较高。
学科领域	热能工程
页数	共53页
文献类型	学位论文
条目标识符	http://ir.giec.ac.cn/handle/344007/1511
专题	中国科学院广州能源研究所
推荐引用方式 GB/T 7714	李理. 生物油热解与燃烧特性的实验研究[D]. 北京. 中国科学院研究生院,2007.