摘要
利用微波网络分析仪测量S_(11)和ψ_(S11)参数,结合人工神经网络模型的计算方法,获取了2 450 MHz微波频率下,内蒙东胜褐煤与澳大利亚Yallourn褐煤在室温至800℃热解过程中的相对介电系数,并用其来表征2种褐煤热解过程中的微波吸收特性。结合热失重实验数据分析发现:热解开始温度之前,DS与YL褐煤的吸波特性参数ε',ε″及tanδ数值接近,均处于较低水平,且随温度的上升仅有极小幅度增长。热解开始温度至热解结束温度阶段,2种褐煤的吸波特性参数ε',ε″及tanδ数值随温度的升高均迅速上升,并在热解结束温度附近时达到峰值;DS褐煤的相关数值增长速率和幅度均比YL褐煤大。热解结束温度之后,各项吸波特性参数出现小幅度下降。实验表明,2 450 MHz微波频率下东胜褐煤比Yallourn褐煤具有更好的吸波能力,高温热解后,褐煤的微波吸收能力得到有效增强。
Parameters S_11 and ψS_11 were obtained by measurement using a microwave network analyzer. Dongsheng lignite（ DS） from Inner Mongolia and Yallourn lignite（ YL） from Australia were examined by means of ANN computation techniques,and their relative dielectric coefficients from room temperature to 800 ℃ pyrolysis process at2 450 MHz microwave frequency were acquired. The coefficients are used to characterize the microwave absorption properties of the two lignite in the pyrolysis process. The analysis of the weight loss test data suggest that： Before the initial pyrolysis temperature,DS lignite and YL lignite behave very similarly in terms of ε＇,ε″,and tan δ values,all at a low level and showing a very slight growth as the temperature increases. At the stage from the initial pyrolysis temperature to the pyrolysis end temperature,their characteristic parameters ε＇,ε″,and tan δ increase dramatically with the temperature and reach a peak value in the neighborhood of the pyrolysis end temperature; however,the parameters of DS lignite grow both quicker and more appreciably than for YL lignite. All the wave absorption parameters dicline slightly after the pyrolysis end temperature. The experiments show that Dongsheng lignite has a better microwave absorption capability than Yallourn lignite,and that capability can be obviously intensified by high temperature pyrolysis.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2016年第6期1540-1545,共6页
Journal of China Coal Society
基金
国家自然科学基金资助项目(51174149)
关键词
褐煤
热解
微波
介电系数
lignite
pyrolysis
microwave
permittivity
