Probability Density Function (PDF) Simulation of Turbulent Reactive Gas‐Solid Flow in a Riser

A hybrid Lagrangian‐Eulerian methodology is developed for the numerical simulation of turbulent reactive gas‐solid flow. The SO 2 ‐NO x Adsorption Process (SNAP) in a riser reactor with dilute gas‐solid flow is taken as a test case. A three‐dimensional time‐dependent simulation is performed. By using the transported composition PDF method [1], modeling of the mean chemical source term and mass transfer terms in the gas‐solid flow model equations is no longer needed. A notional particle‐based Monte‐Carlo algorithm is used to solve the transported composition PDF equations. A Finite‐Volume technique is used to calculate the hydrodynamic fields from the Reynolds Averaged Navier Stokes (RANS) equations combined with the k ‐ϵ turbulence model for the gas phase and the Kinetic Theory of Granular Flow (KTGF) for the solid phase [2]. The newly developed hybrid solution technique is tested with the SNAP chemistry that has a total of 13 scalars (i.e., 5 gas phase components and 8 solid phase species) for which the composition fields of the reactive species are calculated. A good agreement between simulated and experimental gas‐outlet composition of a demonstration unit is obtained.