Computational Fluid Dynamics Simulation of Coal Gasification in a Circulating Fluidized Bed Reactor

Abstract

One of the applications of coal as a fuel is the production of gas through circulating fluidized bed technology. The modeling of these systems allows verifying and optimizing the design and operation parameters of gasifiers for analysis and improvement of gasification technologies. The present study applies the fundamentals of modeling a circulating fluidized bed reactor for the gasification of lignite coal at atmospheric pressure, using air and steam as a gasifying agent. The equations governing multiphase flow are described including mass, momentum and energy transport. The Eulerian-Eulerian approach is applied in two dimensions to describe and solve the constitutive equations. The kinetic model considers eight gaseous species, including CO, CO2, CH4, H2, H2O, N2, O2, Tar and four pseudo solid species, including fixed carbon, volatile matter, moisture and ash. The hydrodynamic behavior of the model is analyzed and the resulting species fractions from the gasification process are compared with experimental data.