Combustion properties of kraft black liquors

摘要

This report deals with the results obtained in a study of the phenomena involving the combustion characteristics of black liquor droplets, and the numerical model developed for modelling of combustion properties of black liquor droplets. The model required certain black liquor specific combustion information which was not currently available, and additional data was needed for evaluation of the model. The overall objectives of the project reported here was to provide experimental data on key aspects of black liquor combustion, to interpret the data, and to put it into a form which would be useful for computational models for recovery boilers. The specific topics to be investigated were: 1. the volatiles and char carbon yields from pyrolysis of single black liquor droplets, 2. a criterion for the onset of devolatilization and the accompanying rapid swelling, and 3. the surface temperature of black liquor droplets during pyrolysis, combustion and gasification. The results of the experimental investigations of these areas are presented in chapters 3-5 of this report. Additional information on the swelling characteristics of black liquor droplets was also obtained as a part of the experiments conducted. A summary of swelling characteristics of black liquor, containing new data from this study and in the form of computational model, is included