Evaluation of the combustion behaviour of different coals

The goal of this project was to develop a methodology based on the properties of coal to predict the combustion characteristics of some coals imported to Finland. The main approach was to apply different advanced methods to analyse coal reactivity and to model the initial stages of pyrolysis and combustion. A review of developments on coal combustion behaviour prediction was also carried out. Three different coals were tested. Infrared spectroscopy and traditional fuel analysis were used to compare the structure of the coals studied. Thermogravimetry, flash pyrolysis and an entrained flow reactor were used to evaluate the reactivity of the coals. A mathematical model was developed to calculate the heating, drying, pyrolysis and combustion of a coal particle. The results of the project were promising and a methodology was proposed to evaluate the combustion characteristics of coals imported to Finland. In the first phase of the method laboratory scale tests with FT-JR, traditional and isothermal TG, DSC, and entrained flow reactor are carried out to study the reactivity, emissions and burn-out of the coal. The effects of particle size distribution are calculated with the coal pyrolysis and combustion model. Pilot plant and fullscale tests are carried out if necessary. In the second phase detailed mathematical modelling is used to compute flow and heat transfer phenomena and burn-out in the flame paths of the furnace.