Kinetic Investigations of Kraft Lignin Pyrolysis

This work explores the suitability of the lumping methodology to describe the kinetics of the pyrolysis of Kraft lignin. The formation of gas, tar, and solid products, resulting from the pyrolysis of Kraft lignin, is investigated at different temperatures. Two mathematical models based on the discrete lumping procedure are presented, that consider the product as three lumps (gas, liquid, and solid), while the lignin is assumed to be an additional lump. Predictions of the products’ distribution after pyrolysis are obtained. In addition, a continuum lumping model is developed for the cracking of the liquid product (tar or bio-oil) to obtain lighter components. Results from the models are validated against experimental data obtained in two different fluidized bed reactors.