烘焙预处理对玉米秸秆结构和组分的影响

Effect of Torrefaction Pretreatment on the Structure and Composition of Corn Straw

以玉米秸秆为研究对象,采用低温烘焙技术,在烘焙温度220、240、250、260、280℃和烘焙停留时间20、40、60 min下,利用箱式电阻炉构成的半封闭系统进行烘焙预处理实验,结合扫描电镜、工业分析、元素分析、组分分析和热值分析,探究烘焙温度和停留时间对秸秆元素成分、热值、挥发分、固定碳含量和组分含量等的影响.结果表明:随着烘焙温度和停留时间的增加,秸秆中三组分发生不同程度的降解,使细胞壁产生皱缩,C含量、固定碳和木质素含量及热值增加,O含量、挥发分和半纤维素含量下降,质量产率和能量产率逐渐降低.烘焙温度对秸秆理化性质的影响大于烘焙停留时间.当烘焙温度为240℃,停留时间为60 min时,秸秆品质得到显著提升,为后期制备成型燃料提供了一定的实验依据.

Corn straw are investigated using low-temperature torrefaction technology in a semi-closed system composed of box-type resistance furnace under the temperature of 220,240,250,260,280℃and the residence time of 20,40,60 min.The effects of torrefaction temperature and residence time on the element composition,calorific value,volatile matter,fixed carbon content and component content of straw are explored based on the results of scanning electron microscopy,industrial analysis,elemental analysis,component analysis and calorific value analysis.The results indicate that with the increase of torrefaction temperature and residence time,the three components in the straw are degraded to different degrees,which causes the cell wall to shrink,the C content,fixed carbon content,lignin content and calorific value to increase,the O content,volatile matter and hemicellulose content to decrease,and the mass yield and energy yield to decrease.The influence of torrefaction temperature on the physicochemical property of corn straw is greater than that of torrefaction residence time.The quality of the straw is significantly improved under the temperature of 240℃and the residence time of 60 min.It provides a certain experimental basis for the later production of briquette fuel.