Experimental investigation of intraparticle secondary reactions of tar during wood pyrolysis
Experimental investigation of intraparticle secondary reactions of tar during wood pyrolysis
复制标题
DOI：
10.1016/j.fuel.2012.08.047
复制
发表时间：
2013-02
期刊：
影响因子：
7.4
通讯作者：
Teeranai Pattanotai;Hirotatsu Watanabe;K. Okazaki
中科院分区：
文献类型：
--
作者：
Teeranai Pattanotai;Hirotatsu Watanabe;K. Okazaki
实验研究了木质生物质热解过程中焦油的颗粒内二次反应。为此，比较了粒径<1mm的日本柏木木屑和直径8mm、长9mm的日本柏木木瓶的热解产物（气体、焦炭和焦油）。样品在氩气气氛下在热天平中进行热解。最终反应器温度为600℃，升温速率为0.5K/s。在这些条件下，木屑和木瓶的区别在于颗粒内焦油的二次反应。与木屑相比，木屑的焦油产率降低，而总气产率和炭产率增加。这些结果表明，在木瓶热解过程中，焦油发生了颗粒内二次反应，包括颗粒内焦油分解生成气体和聚合生成炭。研究发现，颗粒内焦油的分解在400 ~ 500℃之间进行，低于焦油的均匀裂解温度。这一观察结果表明，颗粒内的焦油分解可以在作为催化剂的微孔炭表面非均质发生。研究表明，焦油的颗粒内二次反应在大颗粒木材的热解过程中起着重要作用。此外，这些反应有可能在生物质气化中实现焦油的减少，而无需任何额外的焦油去除过程。
This study experimentally investigated intraparticle secondary reactions of tar during the pyrolysis of woody biomass. For this, pyrolysis products (gas, char, and tar) derived from Japanese cypress sawdust (particle size<1mm) and Japanese cypress wood cylinders (8mm in diameter and 9mm long) were compared. The samples were pyrolyzed in a thermobalance under argon atmosphere. The final reactor temperature was 600°C, and the heating rate was 0.5K/s. Under these conditions, the difference between the sawdust and wood cylinder is the intraparticle secondary reactions of tar. The tar yield of the wood cylinder decreases, whereas its total gas and char yields increase when compared with those of the sawdust. These results indicate that intraparticle secondary reactions of tar, which include intraparticle tar decomposition to form gases and polymerization to form char, occur during the pyrolysis of the wood cylinder. It is found that the intraparticle tar decomposition progresses between 400 and 500°C, which is lower than the homogeneous cracking temperature of tar. This observation suggests that the intraparticle tar decomposition can occur heterogeneously on the surface of the microporous char which acts as a catalyst. This study shows that the intraparticle secondary reactions of tar play an important role in the pyrolysis of large wood particles. Moreover, these reactions have the potential to achieve tar reduction in biomass gasification without any additional tar removal process.