(138a) CFD Study on Natural Gas Fluidized Bed Combustors

The increasing availability of high performance and parallel computer environments has stimulated depth studies of complex reactor systems in chemical engineering. Using computational fluid dynamics approach, better description and comprehension of the most important phenomena taking place in the system can be accomplished, resulting in more efficient reactor and process design. Fluidized bed is a relevant system in many applications in process industries. Fluidized bed combustors are important alternatives to conventional ones, due to the fact that they promote large contact area between gas and solids and intense gas mixing throughout the bed, leading to cleaner burning and less pollutants emission, because the relatively low operating temperatures and isothermal profiles. In this work, computational fluid dynamics simulation of a natural gas fed fluidized bed was carried out. The simulated reactor bed was composed by inert particles (sand) with 350 ìm. A two-stage kinetics model for methane combustion was used. Natural gas, the cleanest fossil fuel, was used in the simulated fluidized bed combustor, minimizing pollutant emissions even more. Dynamic simulations were developed with disturbances imposed into process input variables. The behavior of the simulated combustor was analyzed, and then compared to experimental data from literature.