A novel solar expanding-vortex particle reactor: influence of vortex structure on particle residence times and trajectories

Abstract

A novel configuration of Solar Vortex Reactor (SVR), termed the Solar Expanding-Vortex Particle Reactor, is proposed for heating particles for applications such as steam-gasification. This configuration differs from the previous configurations by features including utilising a conical entry at the opposite end of the cavity to the aperture and a radial exit. The new configuration offers potential to achieve a residence time distribution of feedstock particles that increases with the particle size, in a way that is augmented by a vertical orientation of the device. In addition, it also offers potential to mitigate particle deposition onto the reactor window. The effect of changing the reactor geometric features, particle size and total inlet flow rate on the vortex structure, particle trajectories and particle residence time within the reactor flow field is analysed with a three-dimensional computational fluid dynamics (CFD) model employing Lagrangian particle dispersion for the discrete phase. This is used to develop hypotheses of potential mechanisms with which to 1) mitigate particle deposition onto the reactor window, and 2) to preferentially recirculate the larger particles within the chamber. The validity of the CFD model was assessed by comparison with the available published experimental data from related configurations and found to yield good agreement. The model is then used to identify configurations that are predicted to achieve the above two target outcomes. It also finds that the cone angle is a critical geometrical parameter in influencing both of these effects through its influence on the vortex structure and particle trajectories.