温度对木聚糖快速热解产物的影响

Influence of Pyrolysis Temperature on the Xylan Fast Pyrolysis Products

以半纤维素的主要成分木聚糖为原料,利用Py-GC/MS(快速热解-气相色谱/质谱)联用仪进行了快速热解及产物在线检测分析实验,考察了温度对木聚糖热解产物的影响。实验结果表明,木聚糖快速热解生成的可挥发性热解产物随温度的升高逐渐增加,并在700℃下达到最大,此后随温度升高开始降低。乙酸、羟基丁酮主要在低温热解时形成;而丙酮、环戊酮类产物在高温下收率较高;羟基乙醛、羟基丙酮和糠醛等产物则不随温度发生明显的变化。在此基础上,根据主要产物的形成规律,探讨了木聚糖主要热解产物可能的形成机理。

The analytical pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS） was employed to achieve fast pyrolysis of xylan, which was the main component of hemicellulose, and the on-line analysis of the pyrolysis products was carried out. The effects of reaction temperature on the pyrolysis products were investigated. The results indicated that along with the increasing of temperature, the yield of volatile compounds of xylan was firstly increased and then decreased, and the maximal yield was obtained at 700℃. The acetic acid and hydroxybutanone were mainly produced at low pyrolysis temperatures, while acetone and cyclopentanones were obtained with high yields at high temperatures. Hydroxyacetaldehyde, hydroxyacetone and furfural did not show significant changes along with pyrolysis temperature. Based on the above results, the possible formation mechanism of xylan pyrolysis products was discussed according to the formation characteristics of major products.