Investigation of Moving Beds for Heat Recovery from Solid Granular

Abstract

Moving beds have been regarded as a promising alternative for the heat recovery from the gravity-driven granular flow, which includes counter-current moving bed (CCMB) and gravity-driven moving bed (GDMB). However, the heat transfer characteristics still deserve investigating to optimise the direct heat transfer (CCMB) and the indirect transfer (GDMB), particularly for the appropriate particle size in different moving beds. In this paper, the simple analytical models were established to compare CCMB and GDMB in different particle sizes, which was interwoven with the effects of solid granular density, thermal conductivity, the inlet temperature. It was found that, as the technology significantly affected by the solid-to-gas ratio of mass flow rate, CCMB enables the efficient heat recovery for the particles larger than 3 – 4 mm. For the other fine solid granular, GDMB becomes a good candidate once there is enough heat transfer area, fins in the airside and particles mixing in the granular side. It has more advantages in the quick flow with the compact design. The study can provide useful suggestions for improvement and optimisation in the future.