Application of CFD modelling to investigate fluidized limestone reactors for the remediation of acidic drainage waters

To improve the efficiency of limestone utilization within a conical reactor, fluidization behaviour of solid–liquid flow is investigated using Computational Fluid Dynamic (CFD) modelling tools. Three-dimensional, unsteady state simulations using the Granular Eulerian multiphase approach are performed to determine dynamic characteristics of limestone particles within the reactor. The effect of inflow rate of water and limestone loading on flow properties are studied in several conical fluidized limestone reactor (FLR) configurations including a proposed up-scaled model. The results are validated using available lab- and pilot-scale measurements.To understand the influence of drag models on CFD modelling of FLRs, several widely used drag models (such as Gidaspow and Syamlal) available in literature are reviewed. Resulting hydrodynamics from such reviews are incorporated into the simulations, to extract the best suitable sub models. Results from such simulations are compared with lab-scale measurements to confirm the most suitable model parameters for testing the proposed (up-scaled) design of FLR. Experimentally validated Eulerian multiphase models formulated in the present work are of practical significance and highly useful for testing the scaling-up of limestone reactors.