TORREFACTION KINETIC MODEL OF LIGNOCELLULOSIC MATERIALS BASED ON FIBERS THERMAL DECOMPOSITION REACTIONS

摘要

In these last years, in the context of thermochemical conversion processes, the mild thermal process knownrnalso as “torrefaction” has emerged as particularly strategic in view of enhancing the entire biomass chain exploitationrnvalue. In particular the kinetic studies of this process has become important in supporting the design procedurernexpected to widespread the industrial applications linked to torrefaction. The aim of this study consists in proposing arnkinetic model for torrefaction of lignocellulosic materials based on a combination of the three independent reactionsrnset up to describe the thermal degradation of each of the constituent fibres: hemicelluloses, cellulose and lignin. Thisrnapproach is based on the hypothesis proposed by Shafizadeh and McGinnis that assumed that the three fibres, duringrnthermal degradation, present the behaviour they have when they are treated separately. By utilizing thernthermogravimetric data (TGA) of the single fibers, in this work it is demonstrated that it is possible to set up a kineticrnmodel for the thermal degradation of different biomasses that presents an enhanced predictive character. Within therntorrefaction temperature conditions, usually in the range of 475K – 590K, the maximum deviation errors is nearbyrn4% while AAD to 1%.