Modified sulfation model for simulation of pulverized coal combustion

Abstract

This work deals with the development of mathematical techniques for incorporating existing sulfation models into a CFD code for simulation of the flow and heat and mass transfer in multi-phase reacting flow; i.e. in the combustion of pulverized coal with the dry type sulfur absorption process. By compromising the ability to maintain some features of the sulfation, as suggested in literatures with computation time, the model was successfully embedded into FAFNIR, a CFD code by Lockwood et al. and has been used for prediction of SO2 absorption in pulverized coal combustion to compare with experimental data at various conditions. This paper focuses on mathematical representation of the sulfation process by including the effects of temperature on the reaction rate at zero sulfation and during increased sulfate loading or accumulation of product layers. The model is relatively simple and is applicable over a wide range of temperatures, particle sizes and SO2 concentrations. Validation was performed and it was found that the model satisfactorily represents the amount of accumulated sulfate within the entire domain of calculation.