A new coal devolatilization model employing a tabulated-devolatilization-process model (TDP model) is developed, and its validity is investigated by performing a numerical simulation of a pulverized coal combustion field formed by an industrial low-NOx burner in a 100 kg-coal/h test furnace.
Three reference coals are used to characterize the devolatilization process.
The velocity of the moving bed, blending ratio of ash to coal, coal particle size, preheating temperature of coal and initial temperature of ash have obvious influence on the devolatilization process.
The motion of the particle may have an important effect on the shape and position of the flame of volatiles, but it has only a mild effect on the devolatilization process for the particle sizes typical of pulverized coal combustion.
The negative effect of pressure on coal devolatilization is due to the external pressure exerted on volatile species escaping in this process (Lee et al. 1991).
This work presents a procedure for scale-bridging modeling of coal devolatilization, in the presence of experimental error, that puts emphasis on the thermodynamic aspect of devolatilization, namely the final volatile yield of coal, rather than kinetics.
In this comprehensive model, a one dimensional steady state coal bed model already verified through experimental measurements was employed to describe the combustion process on the bed and an oat hulls devolatilization sub model derived from experiments was added to predict the devolatilization process of oat hulls.
This especially includes three kinetic rates for the description of coal combustion, namely coal devolatilization, volatile combustion and char combustion.
Two coal devolatilization models, namely a simple two-step Arrhenius and Chemical Percolation Devolatilization (CPD), are compared.
The apparent volatile yield after the coal devolatilization under CO2 in the EFR was greater than under N2 for all the coals studied.
