【作者】 张力；

【导师】 王树荣；

【作者基本信息】 浙江大学 ， 生物质热裂解（专业学位）， 2016， 硕士

【摘要】 生物质热裂解技术能够制取高品位液体燃料从而实现生物质资源的高效利用,因此对于该技术的研究备受国内外学者关注。然而热裂解制得的生物油成分复杂且性质不稳定导致其不能直接作为动力燃料使用,这同样也一定程度限制了热裂解技术的大规模工业化应用。其中一个重要的原因是缺乏对生物质热裂解机理的深入研究。本文依托相关科研项目,对于生物质三大组分热裂解固体产物的演变以及真实提取生物质三大组分热裂解行为进行了系统的研究。对于生物质热裂解的研究多从挥发分入手,而对固体产物的关注则不多。利用氙灯光照加热试验台研究了纤维素、半纤维素、木质素热裂解的固体产物的变化过程。采用元素分析、SEM、FTIR、XRD等分析方法观察三大组分热裂解各阶段固体产物。纤维素热裂解过程中,纤维素先部分解聚形成低聚纤维素,之后发生糖环开环与糖苷键断裂这一竞争反应。半纤维素热裂解过程中,半纤维素侧链首先发生分解,之后糖苷键被破坏,主链开始解聚,木糖单元较晚才发生反应。木质素热裂解主要发生侧链分解与主链解聚,木质素基本单元的破坏主要发生在最终焦炭形成过程中。不同生物质中各组分的组成和结构都不尽相同。使用白松提取真实纤维素进行热裂解行为的研究,采用元素分析、FTIR、XRD等分析方法探究其详细化学结构。纤维素是由葡萄糖通过β-1,4-糖苷键连接而成。真实提取的纤维素由于其分子量较大且含有丰富的晶状结构,其热稳定性好。纤维素热裂解主要生成左旋葡聚糖、5-HMF、1-羟基-2-丙酮、糠醛等。半纤维素的提取较为困难,因此关于真实提取半纤维素热裂解的研究较少。使用碱法提取白松半纤维素进行热裂解行为的研究。采用元素分析、FTIR、NMR等分析方法探究其详细化学结构并进行分析。软木半纤维素主要由β-1,4-葡甘露聚糖和β-1,4-木聚糖组成。从热裂解动力学以及热裂解产物分布两方面开展对提取半纤维素的热裂解行为的研究。其热裂解主要生成乙酸、5-HMF、糠醛、左旋葡聚糖、丙酮、1-羟基-2-丙酮等。针对生物质的另一重要组分——木质素,采用Bjorkman法提取白松磨木木质素(MWL)进行热裂解行为的研究。利用元素分析、FTIR、NMR等分析方法探究其详细化学结构。白松MWL的基本组成单元为愈创木基型单元,其侧链结构保存较好,具有较高的反应活性。MWL热裂解主要生成愈创木酚类和苯酚类产物。更多还原

【Abstract】 Biomass pyrolysis technology can produce high quality liquid fuels to realize the efficient utilization of biomass, therefore great attention has been paid to this technology in recent years. However, the large scale industrial application of pyrolysis technology has been restricted by the complexity and instability of bio-oil, which may be attributed to the lack of indepth study of biomass pyrolysis mechanism, especially for the pyrolysis of real biomass composition. Supported by relevant research programs, a systematic research of changing process of solid products during biomass compositions pyrolysis and real isolated biomass compositions pyrolysis mechanism is presented in this thesis.For most of the studies of biomass pyrolysis are from the perspective of the volatile, while solid products attract few attentions. The xenon lamp irradiation heating experimental apparatus was used to study the evolution of solid products in biomass compositions pyrolysis. The solid products were studied by elemental analysis, SEM, FTIR, XRD. At the beginning of pyrolysis, oligomer was formed by depolymerization of cellulose. And the ring opening of monosaccharide units and the rupturing of glycosidic bond were competing reactions in the following process. The crystalline structure was destroyed during pyrolysis. The formed coke was smooth and porous. The branches of hemicellulose were dissociated at the first stage. The backbone depolymerized via cleavage of glycosidic bonds followed by the rupture of xylose unit. The formed honeycomb coke was smooth and porous. The dissociation of branches and the depolymerization of aryl ethers were the main reactions during the devolatilization of lignin. The further damage of lignin basic units mainly occurred in the final process of coke formation.The compositions and structures of each component in different kinds of biomass vary greatly. The isolated cellulose from white pine was used in pyrolysis behavior research. Its chemical structure was studied by elemental analysis, FTIR and XRD. Cellulose was mainly composed of glucose connected with β-1,4-glycosidic bond. Due to the large molecular weight and crystal structure of isolated cellulose, it showed strong thermal stability. The typical products from cellulose pyrolysis were levoglucosan,5-HMF, 1-hydroxy-2-propanone and furfural, etc.There were few researches focused on the pyrolysis of isolated hemicellulose because of its difficulty of isolation. The hemicellulose samples isolated from white pine with alkali method was used as model compound in pyrolysis behavior research. Its chemical structure was studied by elemental analysis, FTIR and NMR. The isolated softwood hemicellulose was mainly composed of (3-1,4-glucomannan and β-1,4-xylan. The pyrolysis behavior was studied by analyzing the pyrolysis kinetics and the pyrolytic product distributions. And the typical products included acetic acid,5-HMF, furfural, levoglucosan acetone and 1-hydroxy-2-propanone, etc.For the study of another major component of biomass——lignin, the milled wood lignin (MWL) isolated from white pine through the Bjorkman procedure was used in pyrolysis behavior research. The chemical structure of MWL was characterized by elemental analysis, FTIR, NMR. The basic unit of white pine MWL was guaiacyl type. The abundant branches were well preserved and showed higher reactivity. The typical products from pyrolysis of white pine MWL were guaiacols and phenols.更多还原