Prediction of Tar and Light Gas During Pyrolysis of Black Liquor and Biomass, 2004 International Chemical Recovery Conference

A generalized model for describing the pyrolysis behavior of low-grade fuels is being developed for incorporation into larger combustion simulation models. Using the Chemical Percolation Devolatilization (CPD) model originally developed for coal, light gas and tar yields from black liquor or biomass pyrolysis can be predicted. The initial approach is to measure the average chemical structures in a black liquor sample using 13C NMR spectroscopy. These chemical structures are then used in pyrolysis model predictions. With few changes from the coal-derived kinetic parameters, the model describes the organic pyrolysis behavior of black liquor samples obtained in nitrogen-purged furnace. It is hoped that future black liquor models can be divided into five major components (hemi-cellulose, cellulose, lignin, Kraft lignin and carboxylic acids) which would permit engineering predictions of many forms of biomass. This paper discusses chemical structure and kinetic parameters used to model pyrolysis behavior of black liquor, lignin, and cellulose.