木质素炭与ZSM-5联合催化热解木质素制备芳烃实验研究

Experimental study on catalytic pyrolysis of lignin under char and ZSM-5 for preparation of aromatics

  • 摘要: 为了提高木质素催化热解所得芳烃的产率,本研究以碱木质素为原料,在碱木质素炭和ZSM-5的二元催化体系下进行快速热解实验,选取催化剂比例、热解温度、热解时间等为实验变量,探究碱木质素热解产物中芳烃的变化规律以及碱木质素炭和ZSM-5协同催化作用机理。结果表明,碱木质素催化热解所得芳烃的产量从17 mg/g(未加炭)提高到33 mg/g(炭添加量为1 g),产率增加了近一倍。通过不同工况研究发现,碱木质素快速热解制备芳烃的最佳条件是:碱木质素∶碱木质素炭∶ZSM-5 = 1∶1∶1, 热解温度为500 ℃,热解时间为10 min。机理分析表明,热解过程中碱木质素炭主要起断键作用,而ZSM-5起择形芳构化作用,两者协同作用得到更高的芳烃产率。

     

    Abstract: In order to improve yield of aromatics from catalytic pyrolysis of lignin, alkali lignin was used for rapid pyrolysis experiments under a binary catalysis system of alkali lignin char and ZSM-5. Influence of catalyst ratio and pyrolysis temperature as well as pyrolysis time on aromatics quantity and mechanism of synergistic catalysis of alkali lignin char and ZSM-5 were investigated. The results show that quantity of aromatics has increased from 17 mg/g (without char) to 33 mg/g (with char addition of 1 g), which is about doubled. The optimal conditions for preparation of aromatics are under alkali lignin∶alkali lignin char∶ZSM-5=1∶1∶1 at 500℃ for 10 min. Meanwhile, the mechanism analysis shows that alkali lignin char mainly plays a role in bond breaking during pyrolysis, while ZSM-5 can act as selective aromatization to obtain higher aromatics yield, whose synergistic effects result in higher aromatic yield.

     

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