Computational Fluid Dynamics (cfd) Modeling of a Laboratory Scale Coal Gasifier

Furthering gasification technology is an essential part of advancing clean coal technologies. In order to seek insight into the appropriate operations for the formation of synthetic gas (syngas) a numerical simulation was performed to predict the phenomena of coal gasification in a laboratory scale entrained-flow coal gasifier. The mesh for the model was developed with ICEM CFD software and the chemical and physical phenomena were modeled using the fluid flow solver ANSYS FLUENT. Mesh independence was verified. The model was validated with experimental data from several studies performed on a laboratory scale gasifier. Systematic examination of the model was performed by varying primary and secondary inlet concentrations of steam and oxygen in regular intervals. Studies were also performed to investigate the effects of coal particle size and steam preheat temperatures. The effect of the turbulence model was also investigated by employing two turbulence models. Of the two turbulence models used the standard k-ε model showed the best agreement with experimental data. Model predictions found that increasing the steam concentration or preheat temperatures in the secondary inlet generally decreases production, while increasing and concentrations. Increasing the steam content in the secondary inlet showed no signifigants effects on predicted temperatures in the gasifier. Increasing the oxygen concentration in the primary inlet generally increases exit temperatures, , and production, while decreasing concentrations.It was found that decreasing the particle size increases the , , and concentration, while decreasing the concentrations