生物质与油页岩混合热解特性研究
Pyrolysis characteristics of biomass and oil shale mixture
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摘要: 为了充分利用油页岩和生物质,以生物质和油页岩按照不同质量比的混合试样作为研究对象,采用TG-DSC联用技术进行了热重实验,分析了热解过程特性曲线并计算热解特性参数,采用差减微分法计算了热解动力学参数。结果表明:混合试样DTG曲线分别在低温段及高温段出现2个峰,前者主要是生物质的纤维素及半纤维素挥发分的热解析出,后者主要为油页岩热解析出挥发分;随混合试样中油页岩含量逐渐增多,热解后期逐渐出现因油页岩无机盐热分解吸热过多而出现DSC曲线吸热峰;混合试样低温段挥发分析出量及挥发分综合释放特性指数均大于高温段的值;生物质含量最高的混合试样(生物质与油页岩的质量比为4∶1)的挥发分初始析出温度最低,其挥发分最大释放速度的峰值及挥发分综合释放特性指数均最大;生物质含量较多的混合试样低温段活化能大于高温段活化能的值,油页岩含量较多的混合试样低温段活化能低于高温段的值。Abstract: In order to make full use of oil shale and biomass,the thermogravimetry experiment of biomass and oil shale mixture was performed using the TG- DSC( Thermogravimetric- Differential Scanning Calorimetry) thermal analysis technology. The pyrolysis process characteristics curves was investigated,the pyrolysis characteristics parameters were figured out and the pyrolysis kinetic parameters were calculated using subtractive differential method. The results showed that the DTG curves of mixed sample appeared two peaks at low temperature section and high temperature section respectively,and the former was biomass cellulose and hemicellulose thermal desorption of volatiles and the latter was oil shale thermal desorption of volatile. With the oil shale content gradually increased in the mixture,it gradually appeared the upward DSC curve endothermic peak in the pyrolysis late,because of the absorption excessive calorie of thermal decomposition of oil shale mineral. The value of devolatilisation of volatile and comprehensive release characteristics index of volatile of mixed sample in the low- temperature phase were all greater than the value at high- temperature phase. Initial precipitation temperature of high volatile content of biomass mixed sample in which the mass ratio of biomass and oil shale was 4 to 1 had the lowest temperature,and its maximum of release rate peak values of volatile and the comprehensive release characteristics index of volatile of mixed sample were all the maximum. With the more biomass content of mixed sample,the activation energy value of mixed samples in the low- temperature phase was greater than the value at the high- temperature phase. With the more oil shale content of mixed sample,the activation energy values of mixed samples at the low- temperature phase was lower than value at the high- temperature phase. The research results provided a theoretical reference for the mixture of oil shale and biomass to pyrolysis gas or liquid fuel.
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