Effect of operating conditions on the drying of fine and ultrafine sand in a fountain confined conical spouted bed

Abstract

A study has been carried out on the influence process conditions and design parameters have on the drying in a conical spouted bed. Optimum parameters have been determined for the draft tube and the fountain confiner. Drying time is reduced when the spout region is enlarged. A distance between the bed surface and the lower end of the confiner in the 0.10–0.15 m range and a confiner of 0.5–0.9 m length minimize the drying time. Longer distances do not avoid entrainment, and shorter distances lead to higher pressure drop and minimum spouting velocity. Longer fountain confiners do not reduce significantly the drying time. Draft tubes with a reduced aperture ratio lead to longer drying times due to their adverse effect on the gas–solid contact. Aperture ratios above 60% cause a decrease in the efficiency of the process due to the higher gas flow rates required to achieve spouting regime.

Keywords:

• Spouted bed
• fine sand
• drying
• fountain confinement
• fluidization

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been carried out with the financial support from the Ministry of Economy and Competitiveness of the Spanish Government, co-funded with European Regional Development Funds (EDRF) [Project CTQ2016-75535-R], the University of the Basque Country UPV/EHU (US16/21) and the collaboration of Novattia Desarrollos Ltd. Aitor Pablos is grateful for a Ph.D. grant from the University of the Basque Country UPV/EHU.