生物质组分的^(13)C-NMR特征及CPD热解模拟探究

^(13)C-NMR Characteristics of Biomass Components and CPD Pyrolysis Simulation

采用核磁共振碳谱(nuclear magnetic resonance spectra,13C-NMR)对生物质的三种最主要组分纤维素、半纤维素及木质素的化学结构特性进行研究,结果表明纤维素中的脂碳与芳碳比明显高于半纤维素和木质素,分别为5.2∶1、1.9∶1和1∶1.2,这直接导致了三种组分热解产物的差异。该文在前人研究的基础上建立适用于生物质组分化学结构的化学渗透脱挥发分(chemical percolation for devolatilization,CPD)模型,通过13C-NMR对生物质各组分的化学结构进行研究,得到CPD模型的4个输入参数;并预测了纤维素、半纤维素及木质素这三种组分的热解产物产量。根据各组分在生物质原样中所占比例,计算出松木屑热解的产物产量。

The characteristics of the chemical structure of the cellulose, hemicellulose and lignin ,three components of biomass, were studied by nuclear magnetic resonance spectroscopy （^13C- NMR）. The results reveal that aromatic and aliphatic carbon-carbon ratio in cellulose was significantly higher than those in hemicellulose and lignin,5.2 ： 1,1.9 ： 1 and 1 ： 1,2, respectively, which led directly to the difference of the pyrolysis products of the three components. Based on the previous studies, a chemical percolation （CPD） model for biomass devolatilization was established. The chemical structure of each component of biomass was studied by ^13C- NMR, and four input parameters of CPD model were obtained. The pyrolysis yield of the three components were predicted. According to the content of each component in pine sawdust, the product yield of pine sawdust pyrolysis was calculated.