Experimental performance of gas-solid countercurrent fluidized bed particle solar receiver with high-density suspension

The particle-based concentrated solar power plant has attracted more attention since its higher working tem-perature. A particle solar receiver based on the gas-solid countercurrent fluidized bed was proposed to realize the high-density suspension and high outlet temperature of particles. To demonstrate the feasibility of this concept, a lab-scale single tube prototype was established and an electromagnetic heating furnace with an electric power of 10-40 kWel was selected to provide heating power. Based on a series of experimental testing, the results revealed that the countercurrent fluidized bed receiver could operate stably in the fluidized state as gas-solid counter-current flow with bubbling and the average solids holdup of-40% was achieved, resulting in a particle tem-perature increase ranging between 101 and 312 C. The global wall-to-bed heat transfer coefficient with a range of 311 to 1481 W/(m(2).K) was obtained by the experimental data. The effects of the input heat flux fluctuation on the countercurrent fluidized bed particle solar receiver were studied to reveal its operating characteristics. These results demonstrated that the receiver may combine the merits of the up bubbling fluidized bed and the Downer, which are long residence time, high solids holdup, lower solids back mixing, avoid slugs and excellent heat transfer. The suspension operating in the fluidized state of countercurrent flow with bubbling has the potential to open a new domain of gas-solids two-phase flow. The novel concept appears to provide a potential technique to applicate in concentrated solar power generation.