Kinetics and Mechanism of Alkali Lignin Catalytic Pyrolysis Based on Thermogravimetric Analysis

Catalytic pyrolysis is a promising method for lignin degradation under anaerobic conditions. In this article, the effect of synthesized Co-based catalysts supported on acid-modified attapulgite catalysts on lignin pyrolysis was analyzed by thermogravimetric analysis, and its reaction mechanism function about lignin pyrolysis was investigated. It was shown that the pyrolysis processes of lignin alone and lignin catalytic pyrolysis were divided into three stages (early pyrolysis-midway pyrolysis-end pyrolysis), and the maximum weight loss peaks all showed a tendency to shift toward the high temperature as the heating rate increased due to the heat transfer limitation. The lowest activation energy of lignin catalytic pyrolysis was 44.7 kJ/mol, which was significantly lower than the conventional activation energy of lignin pyrolysis, indicating specific catalytic interactions between the catalyst active sites and the key functional groups in lignin. The results indicated that the addition of a catalyst could effectively improve the reaction rate of lignin pyrolysis.