不同炭化参数棉秆炭的燃烧特性及其综合评价

Combustion characteristics and its comprehensive evaluation of cotton stalk char at different carbonized parameter

为了制备燃烧性能优良的棉秆炭,文章利用热重法测试了不同炭化参数棉秆炭的燃烧特性,并对其进行了综合评价。分析棉秆炭的燃烧失重过程后发现:棉秆炭的失重峰是由挥发分燃烧峰、固定碳燃烧峰和挥发灰挥发峰叠加而成;随着炭化温度和时间的增加,棉秆炭所含的挥发分含量减少,灰分含量增多,着火温度增加;随着炭化温度和时间的增加,棉秆炭的固定碳含量、挥发灰含量、燃尽温度、挥发分析出指数D、着火特性指数Z、燃尽特性指数H、综合燃烧特性指数S未见明显规律。利用灰色综合评价法对棉秆炭的多个燃烧指标进行综合评价,结果发现,300℃炭化2 h所制得的棉秆炭的燃烧指标关联度值为1.834 5,燃烧性能最佳。

In order to prepare the high-performance of cotton stalk char, the thermal decomposition behavior of the complex was studied by thermogravimetry（TG） at the different heating parameters,and combustion characteristic of cotton stalk char was assessed by comprehensive assessment method.Based on the thermal analysis experimental results, the zero-g periods of cotton stalk char during adiabatic oxidation process under the different conditions is separated into four stages which are respectively the stacking of volatile peak, fixed carbon peak and evaporation ash peak, overlapped peaks with each other. The results showed that volatile content of cotton-charcoal decreases, residual ash content increases, ignition temperature increased with the increase of carbonization temperature and time. Volatile content of cotton-charcoal decreases, residual ash content increases, ignition temperature increases with the increase of carbonization temperature and time. The content of fixed carbon, the content of evaporation ash, burning completely temperature, volatile releasing index（D）,ignition characteristic index（Z）, burn-out combustion characteristic index（H） and synthetic ignition characteristic index（S） change unregularly with the increase of carbonization temperature and time.The grey comprehensive evaluation approach was used to evaluate the combustion index. It is found that correlation degree value of combustion index which the time of carbonizing is two hours under the300 ℃, is 1.834 5 for the optimal condition.