基于TG-FTIR的生物油重质组分热解特性研究

STUDY ON PYROLYSIS OF HEAVY FRACTIONS OF BIO-OIL BY USING TG-FTIR ANALYSIS

利用热重红外技术在线分析了3种生物油重质组分模型化合物(丁香酚、3,4-二甲氧基苯甲醛、左旋葡聚糖)在10,20,30℃/min升温速率下的热解特性,热重试验结果表明:酚类物质最易热解,其次是醛类物质,再次是糖类物质;提高升温速率有利于热解反应的进行,但对最终失重量无影响。红外检测数据表明:左旋葡聚糖的热解分为两段,前段主要为脱水反应,生成醛等小分子物质,后段遵循醛类物质热解的机理,主要产物为小分子的不饱和烃类和CO_2,并伴随有少量的醚和H_2O生成。

The pyrolysis behaviors-of model compounds of bio-oil heavy fractions （Eugenol, Levoglucosan and 3,4-Dime-thoxybenzaldehyde）were studied at different heating rates （10℃/min , 20℃/min, 30℃/min） by thermogravimetfic （TG） analysis coupled with Fourier,Transform Infrared Spectroscopy （FTIR）. The curves of TG and corresponding DTG were analyzed. The results showed that the hydroxybenzenes had the greatest tendency to decompose, followed by the al-dehydes and carbohydrate. The pyrolysis reactions were accelerated by increasing heating rate. However, there were no differences among the ultimate Weight losses. The qualitative analysis of various phases in levoglucosan pyrolysis was based on online FTIR. It indicated that levoglucosan pyrolysis occurs in two steps： First, it was dehydrated into small molecules such as aldehydes; and then followed by the cracking of aldehydes. The products mainly consisted of unsatur-ated hydrocarbon, carbon dioxide, minor ethers and free water.