Ecology & Safety, Volume 8, 2014

Abstract: CFD modeling and simulation are made on the key flow elements, vertical, horizontal pipes and elbow pipes, used in the pneumatic coal-transport system of fluidized-bed gasification test facility. The coal-gas flow inside the flow elements are modeled by combining Reynolds-stress Averaged Navier-Stokes equations Solver (RANS), k-εturbulence model and Discrete Phase Model (DPM) in the ANSYS Fluent code. Using the developed coal-gas flow analysis model, computations are carried out to investigate the gas flow path, the coal particle behavior and the pressure loss characteristics in flow element at various coal/gas loading ratio and coal mass flux. The present prediction results show the coal-gas flow behavior of each flow element is changed from dilute-flow to dense-flow pattern at a specific coal/gas loading ratio where pressure loss is abruptly increased. From the numerical results, the present study also provides the limiting coal/gas loading conditions to secure stable coal feeding and the correlations for pressure losses in horizontal, vertical and elbow pipes, which can be suitable for the design guidelines of actual fluidized-bed coal gasification.