Heat and mass transfer in gas-solid packed beds

The present thesis probes the heat and mass transfer phenomena in packed bed of particles. The gap in literature for realistically packed dense particle packings is explored, following which a new methodology to study external heat transfer is presented and evaluated with deep sensitivity analysis. The newly developed method is applied to obtain new closure models for external heat and mass transfer in packed beds of mono-disperse spherical particles and cylindrical particles of different aspect ratios. In addition, the obtained data helps refit the new Ergun constant for pressure drop in these dense packings. A step by step examination for internal mass transfer and reactions depending upon several levels of complexities in literature i.e. different reaction order, multiple reacting species, and gas volume generation/consumption and in practical application of steam methane reforming reveals the need for improvement in industrially viable 1D models. The developed closure models for external heat and mass transfer along with the data from computationally expensive particle-resolved direct numerical simulations (PR-DNS) in dense packings of monodisperse spherical particles with catalytic reactions inside the porous particles are used to verify and improve the internal mass transfer closures for 1D models through multiscale modelling. The enhanced 1D model is then used to simulate an industrial scale packed bed chemical looping reforming (PBCLR) reactor. As an application of the work done in this PhD, an alternative to resolved 3D simulation is also presented in this thesis in form of non-resolved Euler Lagrange 3D simulations. The results obtained are documented and discussed in appropriate chapters of this thesis