玉米芯稀酸水解残渣热解特性

Pyrolysis Characteristics of Corncob Dilute-acid Hydrolysis Residue

在热天平分析仪上对比分析了玉米芯水解残渣、玉米芯及残渣木质素的热失重特性,借助TGA-FTIR解析了残渣木质素热解过程中主要产物的析出特性,在自制小型快速热解装置上对比考察了水解残渣和玉米芯的热解产物分布,并进一步对比分析了热解气的组分组成及热解焦的气化反应性。TGA结果表明,玉米芯热解主要集中在250～450℃,而水解残渣和残渣木质素的热解温度范围为180～800℃。TGA-FTIR分析显示,甲醇和酚类的主要析出温度区间为200～420℃,而CO和CH4主要在400℃以后析出。在热解温度550～850℃内,水解残渣的固体热解焦产率为30.35%～42.64%,远高于玉米芯热解的固体产率19.18%～26.40%,且残渣热解焦的气化反应性低于玉米芯热解焦;气体组分中CO和CO2产率较高,H2产率在温度高于650℃时明显提高。

The mass loss characteristic of corncob acid hydrolysis residue （CAHR）, corncob and lignin isolated from CAHR （CAHL） were analyzed by using a thermal-gravimetric analyzer （TGA）. The evolution of main volatile products pyrolyzed from CAHL was characterized by TGA coupled to Fourier transform infrared spectrometry （TGA - FTIR）. Pyrolysis behavior of CAHR and corncob was then investigated on a self-designed pyrolysis apparatus, furthermore, component of pyrolysis gas and char reactivity were also examined. Results of TGA showed that an abrupt mass loss stage tor corncob was observed within narrow temperature zone from 250℃ to 450℃ , while the CAHR and CAHL decomposed gradually from 180℃ to 800℃. It was indicated by TGA -FTIR that methanol and phenols were released at low temperature of 200 - 420℃ , and that CO and CO2 mainly released after 400℃. The char yield （30. 35% ～42. 64% ） from CAHR at 550 - 850℃ was much higher than that （19.18% ~ 26.40% ） from corncob, and CO2 gasification reactivity of CAHR char was lower than that of corncob char. The yield of CO, CO2 was higher compared with that of H2 and CH4 , and H2 yield was notably enhanced at pyrolysis temperature over 650℃.