木质素催化快速热解的解聚增值研究进展

Advances in value-added depolymerization by catalytic fast pyrolysis of lignin

木质素是一种复杂的三维非晶态天然芳香聚合物,将其转化为生物燃料替代传统化石能源方面展现出巨大潜力。热解技术已被证实是将木质素转化为高值化学品的有效途径,然而,直接热解过程中普遍存在产物选择性低、产物稳定性差等难题,这些问题限制了木质素的高效转化及工艺经济性。目前,催化快速热解技术在克服上述挑战方面已经取得了显著进展。本文详细阐述了木质素的基本结构单元与其多样的连接模式,介绍了木质素的主要来源和不同种类。基于木质素的热解特性,对其热解过程的关键阶段(初始阶段、主要阶段和碳化阶段的演变)进行了深入阐述。本文还对催化快速热解的必要性进行了探讨,并对常用催化剂进行了全面介绍和综述。最后,对木质素催化快速热解在解聚和增值方面的未来发展方向进行了展望。

Lignin is a complex three-dimensional amorphous natural aromatic polymer with great potential to be converted into biofuels as an alternative to traditional fossil fuels.Pyrolysis technology has been proven to be as an effective pathway for converting lignin into high-value chemicals.However,there are challenges such as low product selectivity and poor product stability in the direct pyrolysis process,which limit the efficient conversion and economic viability of lignin-based conversion.Currently,catalytic fast pyrolysis technology is regarded as a useful technology in overcoming these challenges.This paper extensively elaborates on the intricate structure of lignin by introducing its basic structural units and the multitude of linkage patterns it encompasses.Furthermore,it reviews the primary sources and diverse classifications of lignin.Subsequently,based on the pyrolysis characteristics of lignin,the key stages of its pyrolysis process,including the initial,primary,and carbonization stages,are extensively discussed.Due to the unsatisfactory quality of the direct pyrolysis products,this paper also explores the necessity of catalytic fast pyrolysis and provides a comprehensive introduction and overview of commonly used catalysts.Finally,the paper proposes the future development directions of lignin catalytic fast pyrolysis in terms of depolymerization and value addition.