几种生物质的TG-DTG分析及其燃烧动力学特性研究

TG-DTG analysis and combustion kinetics characteristic study on several kinds of biomass

采用热重分析技术对木屑、麦秆、玉米秆和玉米芯4种生物质的燃烧特性进行了研究,考察了其着火、燃尽特性和综合燃烧特性,研究了升温速率对生物质燃烧特性的影响,同时在热天平上对其进行了动力学试验研究。研究表明:生物质燃烧过程大致可以分为3个阶段,即水分析出阶段、挥发分析出燃烧阶段、固定碳燃烧与燃尽阶段;生物质具有着火温度低、燃尽温度低、燃尽率高等优点;随着升温速率的提高,着火温度、各试样挥发分最大释放速率、燃尽温度均呈升高趋势,燃烧特性随升温速率的提高而变好。采用一级反应动力学模型和积分法对生物质燃烧动力学参数的研究表明,生物质具有较低的活化能,有利于点燃。

Four samples of biomass, which are wood dust, wheat straw, corn straw and cob, were analyzed on their combustion properties through the TG-DTG technology. The ignition, burn-out characters and the integrated combustion properties of each sample were studied. Further more, the combustion characters of biomass with the rise of heating rate were analyzed and the combustion kinetic parameters of biomass combustion process are measured. Based on simultaneous thermal analysis, the combustion process of biomass can be broadly separated into four stages： evaporation of water, release and combustion of volatile, combustion of fixed carbon and burning out. The experiment results indicate that biomass has some better combustion characteristics. They are revealed that biomass has a low ignition point, low burn-out temperature and high burn-off rate. It is verified that the low ignition temperature, the maximum release of volatile and the burn-out temperature will be increased along with the increasing of the heating rate, and the combustion characters turn better with the rise of heating rate. Kinetics parameters of activation energy E and frequency factor A were deduced by reaction kinetics equations. It indicated that biomass has lower E value. So it＇s easy to be ignited.