(270e) Flow Patterns in High Density Fluidized Beds Used As Solar Energy Carrier Systems

Dense gas-solid suspensions have the potential to be applied as heat transfer fluids (HTF) for energy collection and storage in concentrated solar power plants [1]. In the frame of the European CSP2 project [2], a solar receiver using a Dense Particle Suspension (DPS) upward flow in a bundle of tubes was studied. The interest of using as Heat Transfer Fluid (HTF) solid particles transported by an air flow is that the created two-phase medium, exhibits fluid-like flow properties while being able to withstand high temperatures up to the solid sintering temperature. Moreover, the DPS can be used as direct heat storage medium. In the design investigated here, the particles form a dense upward-flowing suspension. Both the density of the SiC particles suspension and their movement have a strong influence on the heat transfer, as demonstrated by Positron Emission Particle Tracking (PEPT) experiments [3].
The NEPTUNE_CFD computational code was used to simulate the DPS circulation both at ambient and high temperature. The numerical results are compared with those obtained on the cold mock-up and with PEPT experiments. The solid reflux evidenced by PEPT experiments was corroborated by simulations and during on-sun experiments [4].
Finally, the DPS flow is analysed highlighting the impact of the air velocity and the density variation along the tube height and the strong influence of the various operating parameters on the temperature distribution. The results of this study will be useful when planning for solar energy capture systems scale-up.

References:

[1] Gilles Flamant, Daniel Gauthier, Hadrien Benoit, Jean-Louis Sans, Roger Garcia, Benjamin Boissière, Renaud Ansart, Mehrdji Hemati, Dense suspension of solid particles as a new heat transfer fluid for concentrated solar thermal plants: on-sun proof of concept; Chemical Engineering Science 102, 567-576
[2] FP7 EC project CSP2. http://www.csp2-project.eu.
[3] Pablo Garcia-Trinanes, Jonathan Seville, Benjamin Boissiere, Renaud Ansart, Thomas Leadbeater, David Parker. Hydrodynamics and particle motion in upward flowing dense particle suspensions: Application in solar receivers. Chemical Engineering Science, (2016) 146:346-356.
[4] H. Benoit, I. Pérez López, D. Gauthier, J.-L. Sans, G. Flamant. On-sun demonstration of a 750 C heat transfer fluid for concentrating solar systems: Dense particle suspension in tube. Solar Energy, (2015) 118:622â??633

*Updated contact details: P.GarciaTrinanes@greenwich.ac.uk