NUMERICAL EVALUATION OF A ONE-DIMENSIONAL TWO-FLUID MODEL APPLIED TO GAS-SOLID COLD-FLOWS IN FLUIDISED BEDS

Computational demanding two- and three-dimensional two-fluid models are frequently adopted simulating gas-solid flows in fluidised beds. Reduced computational cost is favourable for efficient numerical studies of technologies such as the novel chemical looping combustion (CLC), chemical looping reforming (CLR), and sorption-enhanced steam methane reforming (SE-SMR) processes. In this study, we elucidate the potential of a one-dimensional two-fluid model to describe gas-solid cold-flows in fluidised beds. The validity of the numerical simulation results of the bubbling beds and risers have been compared to experimental data in the literature. Moreover, sensitivity analyses on drag closure laws and operation condition have been performed and a number of model solution techniques and algorithms are studied. In addition, simulation results of the one-dimensional model are compared to results of a two-dimensional model. For particular sets of operating conditions and flow characteristics, the one-dimensional model compares fairly well to the simulation results of the two-dimensional model and to experimental data. Under other operating conditions, large quantitative deviations can be observed. However, the one-dimensional model is assumed to be sufficently accurate for particular reactor process optimisation and design evaluations.