Numerical simulation of gasification: Effect of injection velocity on the feedstock conversion and syngas composition

Gasification is a thermochemical pathway that is use to convert feedstock into combustible syngas (CO and H₂). In the following research a computational fluid dynamics study is performed to model the gasification of discrete coal particles stream using air as oxidizer. The main objective of the study is to understand the effect of the oxidizer´s velocity on the conversion of coal particle and syngas composition. Initially the chemical composition of coal particle is measured using the proximate, ultimate and calorimetric analysis. The measured results are used to define the coal properties in the numerical simulation. Afterwards, a parametric study for inlet velocity of oxidizer is performed. The result shows that at lower velocities complete conversion of coal can be attained but at the same time the quality of syngas is degraded due to the formation of CO₂ and H₂O. On the other hand the increase in velocity tend to reduce the conversion of coal particle due to decrease in residence time in the gasifier. Further result of CO and H₂ mole fraction, temperature and velocity contours are also presented.