Effect of locating the atomizer at the inlet in fountain confined conical spouted beds for drying kaolin suspensions

Abstract

The drying of suspensions in a spouted bed is usually performed by atomizing the solution onto the surface of the bed. However, drying of concentrated suspensions, such as those of kaolin, leads to particle agglomeration. Placing the atomizer at the air inlet pipe might be an alternative, since suspension droplets are fed into the spout, where high particle velocities are attained. Moreover, the presence of the fountain confiner above the bed surface allows increasing the air-solid contact. However, the atomizer may lead to bed instabilities due to changes in the air trajectory. Therefore, the spouted bed performance for drying kaolin suspensions with this new atomizer location has been addressed. Spouted bed hydrodynamics with and without atomizer were evaluated and drying experiments were conducted in this new setup. Although the atomizer increases the total pressure drop of the system, it hardly changes spouted bed hydrodynamics. Furthermore, the new setup allows operating at the maximum dryer’s capacity.

Keywords:

• Conical spouted bed
• kaolin suspensions
• hydrodynamics
• atomizer
• drying
• fountain confiner

Additional information

Funding

This work has received funding from Spain’s Ministry of Science and Innovation (PID2019-107357RB-I00 (AEI/FEDER, UE) and PLE2021-008062 (European Union NextGenerationEU/PRTR)), the European Commission (HORIZON H2020-MSCA RISE-2018, Contract No.: 823745), and the Basque Government (IT1645-22). Xabier Sukunza thanks the Ministry of Economy and Competitiveness for his Ph.D. grant (FPU18/04935). Maider Bolaños is grateful for her Ph.D. grant (PIF21/69) from the University of the Basque Country UPV/EHU. Euskal Herriko Unibertsitatea; Eusko Jaurlaritza; Spain’s Ministry of Economy and Competitiveness.