炭化条件对黑沙蒿生物炭产率的影响

Effects of carbonization conditions on biochar yield from Artemisia ordosica

【目的】研究炭化温度、炭化时间和升温速率对沙蒿制备生物炭产率的影响,为沙蒿生物炭的应用提供依据。【方法】通过无氧炭化法,研究不同炭化温度(300,400,500,600,700,800和900℃)、炭化时间(5,15,30,60,90和150min)和升温速率(50,100,150,200和250℃/h)对沙蒿生物炭产率的影响,用傅里叶变换红外光谱仪获得红外光谱图,并据此分析生物炭产率变化的原因。【结果】沙蒿生物炭的产率随着炭化温度升高、炭化时间延长和升温速率的增加而降低。温度从300℃升高至900℃时,生物炭产率降低了75.47%,其中由300℃升高至400℃时降幅最大,为31.90%。由红外光谱图可知,沙蒿生物炭中官能团较炭化前发生变化,主要是由于物料中纤维素或半纤维素、脂肪组分和木质素等组分发生分解和转化;600℃下,炭化时间从5min延长到150min时,生物炭产率降低了6.68%;升温速率从50℃/h增至250℃/h时,生物炭产率降低了5.34%,炭化时间延长和升温速率的升高使木质素在整个生物炭分子中的比例下降,从而使生物炭产率下降。【结论】生物炭产率与炭化温度、炭化时间和升温速率均呈负相关,且炭化温度能够最大程度地影响生物炭产率;造成生物炭产率降低的原因是物料中各组分在不同炭化条件下相继分解和转化。

【Objective】The paper studied the effects of carbonization temperature,time and heating rate on biochar yield fromArtemisia ordosicato improve the application of Artemisia ordosica biochar.【Method】The effects of different carbonization temperatures(300,400,500,600,700,800 and 900 ℃),times(5,15,30,60,90 and 150min)and heating rates(50,100,150,200,and 250 ℃/h)on Artemisia ordosica biochar yield were studied through anaerobic carbonization.Fourier transform infrared spectrometer was used to obtain infrared spectra and the reasons for the changes of biochar yield were analyzed.【Result】Artemisia ordosica biochar yield decreased with the increase of carbonization temperature,time and heating rate.Biochar yield decreased by 75.47% when the temperature increased from 300 ℃to 900 ℃ and the largest decreasing rate of 31.90% happened when temperature increased from 300 ℃ to 400 ℃.Infrared spectra showed that functional groups changed after carbonization,which was mainly due to the decomposition and transformation of cellulose,hemicellulose,lignin components,and fats in materials.At the carbonizationtemperature of 600 ℃,biochar yield reduced by 6.68% when carbonization time increased from 5 min to150 min and it decreased by 5.34% when heating rate increased from 50 ℃/h to 250 ℃/h.Infrared spectrum showed that prolonging carbonization time and increasing heating rate decreased the proportion of lignin in biochar,therefore Artemisia ordosica biochar yield decreased.【Conclusion】Artemisia ordosica biochar yield negatively correlated with carbonization temperature,carbonization time and heating rate.Artemisia ordosica biochar yield was affected by carbonization temperature at the maximum extent due to the decomposition and transformation of components in materials under different carbonization conditions.