论文总字数:21491字
摘 要
人类社会对能源的需求量日益增加,而紧随其后的能源紧缺和环境污染问题,严重制约了人类社会的发展,开发和利用可再生能源成为了人类亟待解决的问题。新能源指的是传统能源之外的其它能源利用方式。其中,生物质能具备污染小、原料供应充足、可再生等优点,其开发和利用受到各国广泛关注。
生物质主要的组成成分是纤维素、半纤维和木质素,生物质本身的热解行为可以被认为是这三种主要组分热解行为的综合表现。本次课题的目的就是探究木质素、半纤维素和纤维素素三种主要成分的含量对生物质快速热解的影响规律。
本次研究的主体是实验部分,利用流化床快速热解装置对松木屑、杨木屑、竹屑、稻秆、麦秆和玉米棒等六种生物质进行了快速热解,温度变化工况选择450、500、550、600℃,粒径变化工况选择0.6-0.8、1.0-1.2、2.0-2.2mm,共进行了36组实验。实验中得到的数据包括产油率、产炭率和产气率。
实验结果表明,生物质的产油率随温度升高先上升后下降,产炭率随温度升高呈下降趋势;产气率随温度升高呈上升趋势。生物质产油率随颗粒粒径增大而减小,这一结果与文献保持一致,确保了实验结果的可靠性。
最后,通过建立一个关联生物质本身特性与热解产物产率的模型,发现生物质中纤维素的含量对产油率的影响很大,木质素和半纤维素对产油率的影响相当;生物质中木质素含量对产炭率的影响很大,较多的木质素含量会导致较多的炭生成;不凝结气体的产率与半纤维素含量相关性较强。同时,较多的灰分会抑制油的生成,从而增大了焦炭的产率。
关键词:流化床;生物质;快速热解;影响规律
Abstract
The demand for energy is increasing in human society, as a result of which the following energy shortage and environmental pollution have seriously restricted the development of human society. The development and utilization of renewable energy has become an urgent problem for human beings to solve. New energy refers to other energy utilization methods besides traditional energy sources, among which biomass energy has the advantages of low pollution, sufficient supply of raw materials and renewable energy. Its development and utilization are widely concerned by many countries.
The main components of biomass are cellulose, hemicellulose and lignin, and the pyrolysis behavior of biomass can be considered as a comprehensive performance of the three main components. The purpose of this project is to explore the effects of three components of cellulose, hemicelluloses and lignin on biomass rapid pyrolysis.
The experiments play the main role in this project, in which six kinds of biomass, including pinewood chips, cottonwood chips, bamboo chips, rice straw, wheat straw and cornstalk were rapidly pyrolyzed. 450, 500, 550 and 600℃ were selected as the temperature variation conditions. 0.6-0.8, 1.0-1.2 and 2.0-2.2mm were selected for the change of grain size, and 36 experiments were carried out. The data obtained in the experiment includes oil production rate and carbon production rate, from which the gas production rate can be calculated with a mass balance.
The experimental results show that the yield of biomass rises first and then decreases with the increase of temperature. The carbon yield decreases with the increase of temperature, and the rate of gas production increases with the increase of temperature, the result of which is consistent with the literature and ensures the reliability of the experimental results.
Finally, by establishing a model related to the characteristics of biomass and the yield of pyrolysis products, it is found that the content of cellulose in biomass has a great influence on the oil production rate. Lignin and hemicellulose have the equivalent effect on the oil production rate; the lignin content in biomass has a great influence on the carbon yield, and the more lignin content will lead to the content of lignin. The yield of non-condensable gas is highly correlated with hemicellulose content. At the same time, more ash will inhibit the formation of oil, thereby increasing the yield of coke.
Keywords: fluidized bed; biomass; fast pyrolysis; influence law
目录
摘要 I
Abstract II
目录 III
第一章 绪论 1
1.1 引言 1
1.2课题的背景与意义 1
1.3生物质快速热解 1
1.4国内外研究现状 2
1.4.1快速热解技术的发展及研究现状 2
1.4.2快速热解反应器的发展及研究现状 3
第二章 实验装置与实验方法 4
2.1引言 4
2.2 流化床实验装置 4
2.2.1流化床实验台 4
2.2.2 流化床快速热解辅助实验装置介绍及实物图 5
2.3 实验方案与步骤 10
2.4 工况设置 11
第三章 实验综合分析及数据处理 15
3.1 引言 15
3.2 不同生物质原料分析 15
3.3 松木屑热解实验 16
3.4 杨木屑热解实验 17
3.5 竹屑热解实验 18
3.6 稻秆热解实验 19
3.7 麦秆热解实验 20
3.8 玉米棒热解实验 21
3.9 不同生物质热解结果分析 22
第四章 全文总结与展望 25
4.1 引言 25
4.2 全文总结与实验结论 25
4.3 工作展望 25
致谢 27
参考文献 28
第一章 绪论
1.1 引言
本章内容涵盖了本次课题的研究背景和意义,生物质快速热解制油技术的简介以及国内外对于这一领域的研究情况。
1.2课题的背景与意义
伴随着人类经济的快速发展,人们对能源的需求量也越来越大。据统计,按照2003年的开采速度计算,地球上蕴藏的煤炭将在200年内消耗殆尽,同时,石油与天然气也将在100年内消耗完全,当然这里没有考虑逐步被发现的新矿源。化石能源的大量使用还会对环境造成巨大的负面影响,可以引起温室效应和污染等环境问题。正因如此,开发和利用能够取代化石能源(或能在一定程度削减化石能源用量)的环境友好型可再生能源已成为全世界研究的焦点。
新能源指的是传统能源之外的其它能源利用方式,包括风能、太阳能、地热能、潮汐能、核能、生物质能等。其中,生物质能具有诸多优点:(1)污染小,燃烧产生的SOx和NOx很少,排放的CO2相当于其生长过程中吸收的,碳排放量等于零;(2)原料丰富,我国每年可以利用的生物质能相当于12亿吨标准煤,占能源总消耗量的1/3以上;(3)可再生,生物质能来源于含碳废弃物,其中,我国仅农业废弃物每年产量高达7亿吨,随着农林业的发展,生物质的来源可谓是源源不断[2-3]。
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