温度对澳洲坚果壳生物炭特性影响

Effects of temperature on the characteristics of Macadamia nut shell biochar

以澳洲坚果壳为原料,利用固定床反应器在温度200~700℃制备生物炭,利用元素分析、工业分析、质量产率、能量产率、高位热值、SEM、FTIR分析特性,采用TG分析燃烧特性。结果表明,热解温度升高,生物炭质量产率、能量产率下降,热值增加,700℃时热值达29.16 MJ/kg;生物炭C含量增大,O含量减少,H/O、C/O下降;温度越高,脱水、脱羧、脱甲基越剧烈,生物炭中的-OH、-CH、■等官能团强度降低。SEM可见生物炭表面结构变光滑,有孔隙结构;燃烧特性分析表明,澳洲坚果壳生物炭着火温度、燃尽温度随生物炭制备温度的增加逐渐升高,综合燃烧特性指数逐渐下降,燃烧曲线向高温区转移。

Using Macadamia nut shell(MNS) as raw material, the biochar was prepared in a fixed-bed reactor via pyrolysis temperature(200~700 ℃).The characteristics of biochar were analyzed by elemental analysis, industrial analysis, mass yield, energy yield, and higher heating value(HHV),scanning electron microscopy(SEM) and fourier transform infrared(FTIR).Combustion characteristics were analyzed by thermogravimetric(TG).With the increase of pyrolysis temperature, the mass yield and energy yield of biochar decreased, and the HHV increased, reaching 29.16 MJ/kg at 700 ℃.With the increase of temperature, C content increased, O content decreased, the H/O and C/O ratios decreased.Dehydration, decarboxylation and demethylation occur violently during pyrolysis process at high temperature, and the strength of -OH,-CH,■ decrease.SEM showed that the surface structure of biochar becomes smooth and porous.The analysis of combustion characteristics showed that the ignition temperature and burnout temperature of Macadamia nut shell biochar increased with the increase of the preparation temperature of biochar, the comprehensive combustion characteristic index(SN) decreased gradually, and the combustion curve shifted to the high temperature region.