Use of numerical modeling in the design and scale-up of entrained flow coal gasifiers

A comprehensive model for entrained flow coal gasifiers was developed. In addition to the numerical methods and sub-models conventionally used in the modeling of pulverized coal combustion, a Multi Solid Progress Variables (MSPV) method was used to simulate the gasification reaction and reactant mixing process. The gas flow fields, gas temperature distributions, extent of burnout, and particle trajectories as well as particle concentrations within a two-stage air blown gasifier and its four variations were predicted by using the simulation model. The simulation results provided reasonable explanation on the experimental observations and demonstrated the ability of the model to sensitively account for subtle changes in design parameters such as the throat diameter ratio and swirl ratios of burner injections. It was concluded that the throat diameter was critical for the gas flow field in the entrained flow gasifier, which might control the behavior of molten ash slag deposition on the gasifier wall. The importance of selecting a proper swirl ratio for different burner sets was demonstrated.