Development of a kinetic model for the NOx reduction process by potassium-containing coal pellets

A four step kinetic model was developed to describe the NOx reduction process by potassium containing coal-pellets. The relevance and significance of the different steps considered in the model as well as the considerations assumed to introduce the equations associated to this model were properly discussed. The simulation both of the NOx reduction and carbon conversion evolution shows good agreement with the experimental data obtained throughout lifetime tests at 350 degrees C for samples with different potassium contents. The set of parameters predicted by the kinetic model have physical significance and are helpful in explaining the different behavior exhibited by the samples. Some of these parameters can be correlated with different features of the samples. The potassium loading influences mainly on the kinetic rate constant governing the NOx chemisorption step, thus explaining the increase in selectivity with the catalyst content exhibited by this type of samples.