Elucidation of interaction among cellulose, lignin and xylan during tar and gas evolution in steam gasification.
Elucidation of interaction among cellulose, lignin and xylan during tar and gas evolution in steam gasification.
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DOI：
10.1016/j.jaap.2009.04.008
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发表时间：
2009-09
影响因子：
6
通讯作者：
C. Fushimi;S. Katayama;A. Tsutsumi
中科院分区：
文献类型：
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作者：
C. Fushimi;S. Katayama;A. Tsutsumi
采用连续错流移动床微分反应器研究了生物质模型样品在水蒸气气化过程中气体和焦油的析出速率随时间的变化规律，以阐明生物质主要组分（纤维素、木聚糖、木质素）在气体和焦油析出过程中的相互作用。两种类型的模型生物质样品（样品A：纤维素（65重量%）和木质素（35重量%）的混合物;样品B：纤维素（50重量%）、木聚糖（23重量%）和木质素（27重量%）的混合物）用于实验。在样品A的水蒸气气化过程中，纤维素和木质素之间的相互作用显著抑制了水溶性焦油和气态产物（CO、H2、CH 4和C2 H4）的析出。木质素的初级（初始）分解受到与纤维素热解产物的相互作用的阻碍。CO2的释放明显增强，水溶性焦油的释放延迟。这些结果可能意味着来自纤维素的水溶性焦油的挥发被木质素抑制，然后来自聚合的焦油和木质素的焦炭发生分解，主要释放CO2。从使用样品B的结果发现，木聚糖的添加极大地增强了气体（CO2、CO、CH 4和H2）的释放，并加速了水溶性焦油和CO2的释放，这意味着增强了水溶性焦油分解成气体和/或木聚糖分解成气体，而没有与纤维素或木质素的显著相互作用。此外，使用HPLC测量主要焦油组分（左旋葡聚糖、糠醛和5-甲基糠醛）的产率。结果表明，纤维素、木聚糖和木质素之间的相互作用抑制了左旋葡聚糖的生成，并显著提高了5-甲基糠醛的生成速率。纤维素、木聚糖和木质素之间的相互作用对糠醛的生成影响不大。
Time profiles of evolution rates of gas and tar in steam gasification of model biomass samples were examined using a continuous cross-flow moving bed type differential reactor to elucidate the interaction of the major biomass components (cellulose, xylan, lignin) during gas and tar evolution. Two types of model biomass samples (sample A: mixture of cellulose (65wt%) and lignin (35wt%); sample B: mixture of cellulose (50wt%), xylan (23wt%), and lignin (27wt%)) were used for the experiment. In steam gasification of sample A, the evolutions of water-soluble tar and gaseous products (CO, H2, CH4and C2H4) are significantly suppressed by the interaction between cellulose and lignin. The primary (initial) decomposition of lignin is hindered by the interaction with pyrolysate of cellulose. Then, the CO2evolution appreciably enhanced and the evolution of water-soluble tar delays. These results may imply that the volatilization of water-soluble tar derived from cellulose is suppressed by lignin and then the decomposition of char derived from polymerized saccharides and lignin takes place, emitting mainly CO2. From the results using sample B, it was found that the addition of xylan greatly enhances the evolutions of gases (CO2, CO, CH4and H2) and accelerates the evolution of water-soluble tar and CO2, implying that the enhancement of decomposition of water-soluble tar into gases and/or xylan decomposes into gases without significant interaction with cellulose or lignin. In addition, yields of the major tar components (levoglucosan, furfural and 5-methylfurfural) were measured using HPLC. It was observed that the interaction among cellulose, xylan and lignin suppresses the evolution of levoglucosan and significantly increases the evolution rate of 5-methylfurfural. There is an insignificant influence of interaction among cellulose, xylan and lignin for furfural evolution.