摘要
为了研究生物质高温热解气化特性,特别是在此过程中碳烟的形成机理,在一维沉降炉内对麦秆和杨树木屑于900~1 300℃进行高温热解,收集热解产生的气、液、固三相及碳烟产物,对热解产物的产率(产物与生物质干基的质量比)、形貌及组分进行分析,对比了两种生物质热解产物特性并重点分析热解碳烟的形成机理。结果表明,麦秆、木屑热解碳烟的产率随着温度的升高而升高,分别为0.28%~2.40%和0.34%~6.30%,热解焦炭的产率随着温度的升高逐渐降低,分别为2.8%~7.3%和0.29%~2.9%。木屑由于具有较高的木质素和纤维素组分,会产生更多的碳烟;麦秆由于具有高灰分和抽提物含量,会生成更多的焦炭。麦秆的不凝性气体产率为47%~69%,木屑的为59%~77%,热解产气率总体随温度的升高而升高。两种生物质热解的焦油产率均低于1.6%,温度升高至1 200℃时焦油完全转化,焦油的组分几乎均为芳烃类物质。生物质的热解过程中,在900~1 100℃时,碳烟的形成为小分子烃类气体裂解和大分子焦油缩聚机理共同作用的结果,在温度超过1 100℃时,增长的碳烟主要是通过小分子烃类气体裂解的途径生成。
To study the pyrolysis/gasification characteristics of biomass under high temperature conditions,in particular the formation mechanism of soot during the process,rapid pyrolysis of wheat straw and poplars sawdust was conducted in a lab scale drop tube furnace(DTF)at9001300℃.Three phase products including gas,liquid and solid were collected and characterized to study the influences of temperature and biomass origin.Special attention was paid to the soot formation during the pyrolysis.The results showed that the yields of soot from wheat straw and poplars sawdust were028%240%and034%630%(dry biomass)respectively,with an increasing trend with the temperature,while the yield of char was28%73%and029%29%respectively,with a decreasing trend.More soot was formed due to the high level of lignin and cellulose components in sawdust,and more char was produced due to the high ash and extracts contents in wheat straw.Raising temperature favored the production of uncondensed gas:for wheat straw the production rate of uncondensed gas ranged from47%69%and for sawdust the data were between59%77%.It was found that temperature has a significant effect on tar destruction.The tar dominated by aromatic compounds is decomposed completely at1200℃.When the pyrolysis temperature is relatively low(9001100℃),the soot is formed through the combined mechanism of light hydrocarbon decomposition and heavy tar polycondensation.However when temperature is higher than1100℃,most of the soot is formed by the decomposition of light hydrocarbon.
作者
李艳
谭厚章
王学斌
白胜杰
阮仁晖
杨富鑫
LI Yan;TAN Houzhang;WANG Xuebin;BAI Shengjie;RUAN Renhui;YANG Fuxin(MOE Key Laboratory of Thermo Fluid Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2018年第1期61-68,共8页
Journal of Xi'an Jiaotong University
基金
国家重点研发计划资助项目(2016YFB0600605)
关键词
生物质
热解
三相产物
碳烟
生成特性
biomass
pyrolysis
three phase products
soot
formation mechanism
