Elutriation, attrition and segregation in a conical spouted bed with a fountain confiner--颗粒学报PARTICUOLOGY

Pablos, A., Aguado, R., Vicente, J., Tellabide, M., Bilbao, J., & Olazar, M. (2020). Elutriation, attrition and segregation in a conical spouted bed with a fountain confiner. Particuology, 51, 35-44. https://doi.org/10.1016/j.partic.2019.08.006

Elutriation, attrition and segregation in a conical spouted bed with a fountain confiner

Aitor Pablos ^a, Roberto Aguado ^a *, Jorge Vicente ^b, Mikel Tellabide ^a, Javier Bilbao ^a, Martin Olazar ^a

a Department of Chemical Engineering, University of the Basque Country UPV/EHU, P.O. Box 644, E48080 Bilbao, Spain
b Novattia Desarrollos, Ltd., Scientific and Technologic Park of Bizkaia, Astondo Bidea, Building 612, E48160 Derio, Spain

10.1016/j.partic.2019.08.006

Volume 51, August 2020, Pages 35-44

Received 29 March 2019, Revised 16 July 2019, Accepted 9 August 2019, Available online 15 December 2019, Version of Record 11 April 2020.

E-mail: roberto.aguado@ehu.eus

Highlights

• Particle elutriation, attrition and segregation were studied.

• A new methodology based on colouring and local monitoring of fractions is proposed.

• Breakage is responsible for the majority of particle attrition.

• Elutriation is dramatically reduced by adding a fountain confiner.

• A fountain confiner minimizes both elutriation and segregation.

Abstract

This study examined elutriation, attrition, and segregation in a conical spouted bed with a fountain confiner and incorporating an open sided draft tube. Fine silica sand with a wide particle size distribution was employed as a model material, operating in both the batch and continuous modes. The use of a fountain confiner is crucial when operating with fine particles, because otherwise the bed rapidly exhibits significant entrainment. The extent of attrition was quantified using a tracing technique based on differently-coloured sand fractions as well as monitoring size distributions by sieving. Particle breakage was found to be the primary attrition mechanism, and the fountain confiner was determined to limit the elutriation of fine particles resulting from breakage. Consequently, only a small fraction of the finest particles were entrained from the bed. The incorporation of a confiner increased operational stability while reducing segregation, especially in the upper half of the bed where the majority of segregation typically occurs. Thus, the bed was perfectly mixed apart from very minimal segregation close to the wall and at the bottom of the contactor. These results provide a basis for the design and operation of larger scale equipment for the continuous drying of materials.

Graphical abstract

Keywords

Spouted bed; Fine sand; Elutriation; Attrition; Segregation; Fountain confinement device

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