Catalytic effects of NaOH and Na2CO3 additives on alkali lignin pyrolysis and gasification
Catalytic effects of NaOH and Na2CO3 additives on alkali lignin pyrolysis and gasification
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NaOH和Na2CO3添加剂对碱木质素热解气化的催化作用
DOI：
10.1016/j.apenergy.2012.01.042
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发表时间：
2012-07-01
期刊：
影响因子：
11.2
通讯作者：
Yang, Qing
中科院分区：
文献类型：
--
作者：
Guo, Da-liang;Wu, Shu-bin;Yang, Qing
由于希望生产生物燃料和生物化工产品，通过热解和气化利用黑液中的碱木素的兴趣越来越大。除了碱木质素，钠盐也是黑液的基本成分；它们主要以两种形式存在：作为碱木质素一部分的酚钠(-ConA)和羧酸钠(-Coona)或以溶解盐(NaOH和Na2CO3)的形式存在。本文讨论了这些溶解盐类对碱木素热解和气化特性的影响。选取了纯酸沉木素、10%和60%NaOH负载木素、10%和60%Na2CO3负载木质素和黑液固体等5个木素样品作为测试样本。在热重分析仪和傅里叶变换红外光谱仪上对挥发分的演化规律进行了实验研究。实验数据表明，NaOH和Na2CO3均能催化碱木素的热解和气化反应。在热解阶段，随着NaOH和Na2CO3添加量的增加，最大失重速率减小，而在气化阶段，最大失重速率增大。在气化阶段，随着NaOH和Na2CO3添加量的增加，最大失重速率的温度向较低的值移动，而在热解阶段没有明显变化。FTIR分析表明，NaOH和Na2CO3添加剂对热解和气化产物的影响主要是数量上的差异，而不是种类上的差异。FTIR结果还表明，NaOH和Na2CO3添加剂用量的增加会影响挥发分的释放时间。此外，NaOH和Na2CO3显著促进了气化阶段CO的析出。(C)2012爱思唯尔有限公司。保留所有权利。
The interest in utilization of alkali lignin in black liquor by pyrolysis and gasification is increasing due to the wish to produce bio-fuel and bio-chemical. Besides alkali lignin, the sodium salts are also the basic component of black liquor; they exist in two main forms: as phenolic sodium (-CONa) and carboxylate sodium (-COONa) groups forming a part of alkali lignin or as dissolved salts (NaOH and Na2CO3). In this paper, the influences of these dissolved salts on the pyrolysis and gasification characteristics of alkali lignin were discussed. Five lignin samples, including pure acid precipitated lignin, 10% and 60% NaOH-loaded lignin, 10% and 60% Na2CO3-loaded lignin, and black liquor solids were selected as the testing samples. Following experimental research on the evolution patterns of volatile products were carried Out on a thermogravimetric analyzer coupled with Fourier transform infrared spectrometry. The experimental data indicated that the pyrolysis and gasification reaction of alkali lignin could be catalyzed by NaOH and Na2CO3. In the pyrolysis stage, the maximum mass loss rate decreased with increasing amount of NaOH and Na2CO3 additives, while in the gasification stage it increased. In the gasification stage, the temperature of the maximum mass loss rate shifted to lower value with increasing amount of NaOH and Na2CO3 additives, but did not significantly change in the pyrolysis stage. FTIR analysis showed that the influences of NaOH and Na2CO3 additives on the pyrolysis and gasification products mainly varied in amounts but not in species. FTIR results also suggested that the release time of the volatile was affected by increasing NaOH and Na2CO3 additives amount. Moreover, NaOH and Na2CO3 markedly improved the evolution of CO in the gasification stage. (C) 2012 Elsevier Ltd. All rights reserved.